AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 845 PM MST FRI NOV 30 2007 .SYNOPSIS...AN AREA OF LOW PRESSURE OFF THE BAJA COAST WILL MOVE NORTHEAST ACROSS ARIZONA TONIGHT AND SATURDAY CAUSING RAIN...HEAVY AT TIMES INTO SATURDAY. COLDER TEMPERATURES ALOFT WILL BEGIN TO MOVE INTO THE REGION TONIGHT AND SATURDAY...RESULTING IN A SLIGHT CHANCE OF THUNDERSTORMS...AS WELL AS HIGH ELEVATION SNOW. RAIN IS EXPECTED TO CHANGE OVER TO SNOW ABOVE 8000 FEET TONIGHT...LOWERING TO AROUND 7000 FEET IN THE WHITE MOUNTAINS ON SATURDAY. DRY AND WARMER CONDITIONS ARE THEN EXPECTED DURING THE EARLY TO MIDDLE PORTIONS OF NEXT WEEK AS HIGH PRESSURE RETURNS. ANOTHER SYSTEM MAY IMPACT THE REGION LATE NEXT WEEK. && .DISCUSSION...SATELLITE IMAGERY WAS INDICATING THAT THE UPPER LOW WAS NOW CENTERED NEAR THE SOUTHERN CALIFORNIA AND NORTHERN BAJA COASTS AT 8 PM MST. RADAR CONTINUED TO INDICATE WIDESPREAD LIGHT RAIN ACROSS SOUTHEAST ARIZONA...WITH A BAND OF MODERATED RAINFALL INTENSITY EXTENDING SOUTHWEST FROM PINAL COUNTY THROUGH EASTERN AND CENTRAL PIMA COUNTIES. THIS INCREASE IN RAINFALL RATES OVER A LARGE AREA HAS PROMPTED THE ISSUANCE OF AN URBAN AND SMALL STREAM FLOOD ADVISORY THROUGH MIDNIGHT TONIGHT. THE LATEST RUC MODEL SHOWED A BROAD AREA OF NEGATIVE LIFTED INDEX VALUES DEVELOPING OVER SOUTHEAST ARIZONA BY 09Z SATURDAY AS THE COLD POOL ALOFT ASSOCIATED WITH THE UPPER LOW PASSES THROUGH. THEREFORE...STILL EXPECT THE AIRMASS TO BECOME MORE DESTABILIZED LATER THIS EVENING AND PAST MIDNIGHT FOR A FEW EMBEDDED THUNDERSTORMS OR HEAVIER SHOWERS. THE SNOW LEVEL APPEARED TO BE HOVERING ABOVE 10000 FEET AT 8 PM MST AS AUTOMATED OBSERVATION SITES AT 8000 FEET AND 9000 FEET WERE STILL REPORTING TEMPERATURES IN THE LOWER 40S. THE SNOW LEVEL WAS EXPECTED TO REMAIN RATHER HIGH TONIGHT...BUT WILL LOWER BY SOME SATURDAY MORNING AS COLDER AIR ALOFT MOVES OVER IN ASSOCIATION WITH THE UPPER LOW. IF THE AIRMASS DESTABILIZES ENOUGH...SNOW LEVELS COULD BE CONVECTIVELY LOWERED WITH A BRIEF SHOT OF HEAVY SNOWFALL AT GENERALLY MOUNTAINTOP LEVELS TONIGHT. THE SNOW LEVEL WILL LOWER MORE SATURDAY AS A SHORTWAVE TROUGH APPROACHING FROM THE NORTHWEST ENTERS THE STATE. THEREFORE...A SNOW ADVISORY WILL BE IN EFFECT FROM 10 PM THIS EVENING UNTIL 5 PM MST SATURDAY FOR ELEVATIONS ABOVE 8000 FEET IN EASTERN PIMA COUNTY TO 7000 FEET IN THE WHITE MOUNTAINS. FOR MORE INFORMATION ON THE FORECAST...PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW. && .PREV DISCUSSION...GIVEN THE SUBTROPICAL NATURE OF THIS SYSTEM... SNOW LEVELS ARE EXPECTED TO START OUT RATHER HIGH...ABOVE 9000 FEET. SNOW LEVELS WILL THEN LOWER TO NEAR 8000 FEET SATURDAY MORNING. SNOW LEVELS WILL CONTINUE TO FALL IN THE WHITE MOUNTAINS DURING THE DAY SATURDAY... LOWERING TO NEAR 7000 FEET BY SATURDAY AFTERNOON. SNOWFALL AMOUNTS OF 2-4 INCHES ARE EXPECTED IN THE WHITES TONIGHT ABOVE 8000 FEET...WITH AN ADDITIONAL 3-5 INCHES ABOVE 7000 FEET SATURDAY. THERE MAY ALSO BE AN ADDITIONAL 1-3 INCHES SATURDAY NIGHT IN THE WHITE`S ON THE TAIL END OF THE SYSTEM WHEN THE COLDEST AIR SPILLS INTO THE REGION (LATTER SHIFTS WILL HAVE TO MONITOR THIS AND MAY EVEN HAVE TO EXTEND THE SNOW ADVISORY DEPENDING UPON THE STORMS SPEED AND EVENTUAL EVOLUTION). IN THE MOUNTAINS SURROUNDING TUCSON...WERE LOOKING AT A TOTAL OF 3-5 INCHES ABOVE 8000 FEET...STARTING LATE TONIGHT AND THEN CONTINUING ON SATURDAY. ISOLATED HEAVIER AMOUNTS WILL BE POSSIBLE WHEREVER CONVECTION COMES INTO PLAY. AS THIS SYSTEM LIFTS EASTWARD OUT OF THE REGION LATE SATURDAY INTO SUNDAY AND RIDGING ALOFT STRENGTHENS OVER THE EASTERN PACIFIC... EXPECT CLEARING SKIES FROM THE WEST. BY EARLY NEXT WEEK...THE HIGH PRESSURE RIDGE WILL BUILD ACROSS THE SOUTHWESTERN UNITED STATES... RESULTING IN DRY CONDITIONS AND A RETURN TO ABOVE NORMAL TEMPERATURES. READINGS WILL THEN COOL OFF LATE IN THE WEEK AS A TROUGH DEVELOPS ACROSS THE INTERMOUNTAIN WEST AND ANOTHER SYSTEM MOVES INTO THE ROCKIES. && .AVIATION...PERIODS OF RAIN WITH VISIBILITIES UNDER 3SM MOST AREAS FROM LATE AFTERNOON THROUGH EARLY SATURDAY MORNING...VISIBILITIES WILL OCCASIONALLY FALL TO NEAR 1SM IN HEAVIER SHOWERS AND MIST. CEILINGS WILL FALL TO 2000-3000 FEET...OCCASIONALLY DOWN TO 1000 FEET. CONDITIONS WILL IMPROVE ON SATURDAY...WITH VSBYS GENERALLY GREATER THAN 6 SM AND CEILINGS 4000 FEET OR HIGHER. THE AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .CLIMATE...SIGNIFICANT RAIN EVENT IS ON TAP AS A STORM SYSTEM OFF BAJA CALIFORNIA SENDS COPIOUS AMOUNT OF MOISTURE ACROSS SOUTHEAST ARIZONA. FORECAST RAINFALL TOTALS COULD EXCEED DAILY RECORDS FOR NOVEMBER 30TH. BELOW IS A LISTING OF STATION RAINFALL RECORDS FOR TODAY. STATION NOV. 30 RECORD TUCSON 0.74" / 1982 AJO 0.34" / 1922 ORGAN PIPE 0.56" / 1962 KITT PEAK 1.12" / 2002 ORACLE 0.70" / 1991 PICACHO PEAK 1.20" / 2002 NOGALES 0.26" / 1985 DOUGLAS 0.55" / 1962 SIERRA VISTA 1.05" / 1902 WILLCOX 0.60" / 1921 TOMBSTONE 0.49" / 1962 BOWIE 0.35" / 1952 SAFFORD AG STN 0.29" / 1996 FORT THOMAS 0.49" / 1985 CLIFTON 0.70" / 1962 && .TWC WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY LATE THIS EVENING THROUGH SATURDAY AFTERNOON ABOVE 7000 FEET FOR GRAHAM AND GREENLEE COUNTIES /AZZ019-030/ AND ABOVE 8000 FEET FOR EASTERN PIMA COUNTY /AZZ033/. $$ WEATHER.GOV/TUCSON az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 827 PM MST FRI NOV 30 2007 .UPDATE... LATEST SATELLITE/RADAR/SURFACE OBS SUGGEST MODERATE TO HEAVY PRECIPITATION WAS SPREADING INTO MOST MOUNTAIN AND WESTERN VALLEY ZONES AS OF 03Z...WITH VERY HIGH FREEZING LEVELS (AROUND 10K FEET) KEEPING SNOW LIMITED TO MAINLY HIGHER ELEVATION ZONES. QUICK LOOK AT NEW 00Z NAM SUGGESTS FORECAST FOR MOUNTAIN ZONES/WRN VALLEYS IS MOSTLY ON TRACK...THOUGH SNOW AMOUNTS FOR LOWER ELEVATION ZONES MAY BE OVERDONE AS A GOOD DEAL OF RAIN WILL FALL OVERNIGHT BEFORE MID LEVEL TEMPS COOL SATURDAY AFTERNOON AND CHANGE PRECIP BACK TO SNOW. WILL KEEP CURRENT GROUP OF MOUNTAIN HIGHLIGHTS INTACT...BUT WILL SCALE BACK SNOW ACCUMS IN AREAS BELOW 10K FEET MSL. EASTERN PLAINS FORECAST MUCH LESS CLEAR-CUT...AS NEW NAM HAS LITTLE TO NO PRECIP ALONG AND EAST OF I-25 THROUGH THE NIGHT. ALREADY UPDATED ONCE TO TRIM BACK POPS BEFORE MIDNIGHT...MAY NEED TO CUT BACK AGAIN IF NAM IS ANYWHERE CLOSE TO CORRECT. WILL LET CURRENT ZR ADVISORY RUN FOR NOW... BUT AM SERIOUSLY CONTEMPLATING DROPPING IT FOR ALL ZONES LATER THIS EVENING IF PRECIP IS SLOW TO DEVELOP. PETERSEN && .PREV DISCUSSION... /ISSUED 221 PM MST FRI NOV 30 2007/ SHORT TERM... (TONIGHT AND SATURDAY) ..COMPLEX WEATHER PATTERN OVER THE NEXT 24-36 HOURS... ..FEET OF SNOW FOR THE SOUTHWEST/CENTRAL MOUNTAINS... ..WINTRY MIX STILL POSSIBLE PARTS OF SOUTHEAST CO TONIGHT... ..STRONG/DAMAGE HIGH WIND THREAT SOUTHEAST CO SATURDAY... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED THE OPENING SUB-TROPICAL WEATHER SYSTEM JUST OFF THE CA BAJA MOVING EAST THANKS TO AN UPPER LEVEL JET STREAM AND ASSOCIATED DIGGING TROUGH MOVING JUST OFF THE CA COAST. IN RETURN...VERY DEEP SOUTHWEST FLOW AND HIGH MOISTURE CONTENT AIR WAS STREAMING ACROSS OLD MEXICO...THE DESERT SOUTHWEST INTO UT/CO. 12Z/30 OBS SOUNDINGS ACROSS SOUTHERN CA...AZ...NM...AND SOUTHWEST TX HAD PRECIPITABLE WATER INDICES OF 150-315 PERCENT ABOVE NORMAL VALUES THIS TIME OF THE YEAR...1.19 INCHES AT TUCSON...AZ. 700MB-500MB SPECIFIC HUMIDITY VALUES ARE AROUND 5G/KG...WHICH IS A FAIRLY TROPICAL AIR MASS AND SOMETHING WE SEE AROUND HERE DURING THE SUMMER "MONSOON." GIVEN THE RELATIVELY STRONG MOISTURE TRANSPORT...BANDS OF SHOWERS HAVE BEEN FORMING ACROSS UT...WESTERN CO...AND NM. THERE HAS BEEN SOME PERIODIC SNOWFALL ACROSS THE HIGH TERRAIN PER SPOTTERS...OBS...AND LIVE WEBCAMS. WARM AIR ALOFT ALREADY BUILDING AS LA VETA PASS SENSOR STARTED IN THE 20S THIS MORNING AND MANAGED TO WARM INTO THE MIDDLE 30S DURING SOME PRECIPITATION. THE BOSQUE RAWS IN THE EAST SIDE THE SOUTHERN SANGRE DE CRISTO MOUNTAINS AROUND 8K FT MSL WAS IN THE LOWER 50S...GOTTA LOVE CO COMPLEX TERRAIN. WE RECEIVED A SPOTTER REPORT OF 1.5 INCHES OF SNOW 5 ESE FORT GARLAND(8500 FEET MSL) AND THAT WAS IN ABOUT 6 HOURS. EARLY THIS AFTERNOON...MOST LIVE WEBCAMS(WOLF CREEK PASS...MONARCH PASS...SAN LUIS VALLEY) LOOK RELATIVELY SNOWFALL-FREE. MEANWHILE...S51OW CP AIR MASS WAS ACROSS EASTERN CO INTO THE CENTRAL/SOUTHERN PLAINS. TEMPERATURES ARE STRUGGLING TO WARM IN THE LOWER AR RIVER VALLEY AND MAY NOT MAKE IT INTO THE 30S AROUND LAMAR. SURFACE WINDS WERE ALREADY VEERING TO THE SOUTH-SOUTHEAST ALONG I-25 CORRIDOR AND EASTWARD WITH DEW POINTS IN THE TEENS. FOR THE MOUNTAINS/HIGH VALLEYS LATE THIS AFTERNOON THROUGH SATURDAY...QUITE THE ARRAY OF WEATHER ACROSS MUCH OF CO GIVEN THE VERY COMPLEX AND C51ENGING WEATHER PATTERN. GIVEN THE DEEP MOISTURE FLUX COMBINED WITH ISENTROPIC ASCENT TONIGHT AND OROGRAPHIC ASCENT FOR SOME FAVORED AREAS...SNOW SHOWERS SHOULD BECOME MORE STEADY SNOW...HEAVY AT TIMES...ACROSS THE MOUNTAINS AND HIGH VALLEYS ESPECIALLY FOR THE SAN JUAN...LA GARITA...COLLEGIATE... AND SANGRE DE CRISTO MOUNTAIN RANGES. STILL LOOKS LIKE THE HEAVIEST SNOW WILL BE GENERALLY ABOVE 8K FT MSL...ESPECIALLY AROUND THE MOUNTAIN PEAKS/HIGH MOUNTAIN PASSES. 1-4 FEET STILL LOOKS DOABLE AROUND THE CENTRAL AND SOUTHERN PORTION OF THE CONTINENTAL DIVIDE. LESSER AMOUNTS AS YOU HEAD TO THE LOWER ELEVATIONS. WENT AHEAD AND ADDED ADVISORIES FOR THE LOWER ELEVATIONS OF THE WEST SIDE OF THE CONTINENTAL DIVIDE IN SAGUACHE COUNTY/LA GARITA MOUNTAINS TOWARD THE GUNNISON VALLEY AND THE REST OF LAKE COUNTY INCLUDING LEADVILLE. OTHER LOWER MOUNTAIN VALLEY/HIGH VALLEYS LIKE SAN LUIS AND UPPER AR SHOULD SEE SOME ACCUMULATING LIGHT SNOW...BUT BELOW ADVISORY VALUES. THE SNOW LIKELY ENDS FOR THE SANGRE DE CRISTO/WET/PIKE PIKE MOUNTAINS GIVEN RELATIVELY STRONG ISENTROPIC DOWNGLIDE AS MODERATE-STRONG MIDLEVEL TO SURFACE WINDS DEVELOP. HOWEVER...OROGRAPHIC ASCENT DRIVEN SNOW SHOULD CONTINUE ACROSS THE CONTINENTAL DIVIDE. FOR THE I-25 CORRIDOR AND SOUTHEAST CO PLAINS LATE THIS AFTERNOON THROUGH SATURDAY...VERY TOUGH CALL IN WHAT WILL ACTUALLY OCCUR. STAYED CLOSE TO CURRENT FORECAST GIVEN A NUMBER OF UNCERTAINTIES. IN RESPONSE TO THE CP AIR MASS POSSIBLY RECEDING EASTERN CO AND WARM AIR ADVECTION ALOFT...SURFACE PRESSURE FALLS INCREASE THROUGH THE NIGHT. 295K/300K ISENTROPIC ASCENT DEVELOPS ACROSS MUCH OF NM...EASTERN CO...AND ESPECIALLY KS/OK/TX. TOUGH TO TRULY SAY WHERE THE WARM FRONT WILL BE LOCATED AS ANY PRECIPITATION EVAPORATIVE OR DIABATIC COOLING COULD KEEP THE S51OW COLD AIR LOCKED INTO THE LOWER AR RIVER VALLEY WHILE THE WARM AIR BUILDS OVER EASTERN CO. IF THAT IS THE CASE...THEN THERE STILL COULD BE A WINTRY MIX THIS EVENING AND OVERNIGHT GENERALLY EAST OF I-25 CORRIDOR AND NOT FOR THE RATON MESA OR PALMER DIVIDE GIVEN THE HIGHER TERRAIN. NAM-WRF 12KM SOUNDING FOR EADS HAS A FREEZING RAIN VERTICAL THERMAL PROFILE. HOWEVER...IF THE PRECIPITATION HAS TROUBLES MATERIALIZING...OR INCREASING IN INTENSITY...THEN THE WARM SOUTHERLY WIND COULD TAKE OVER. BOTH THE GFS AND NAM-WRF MOS GUIDANCE HAVE CONSISTENTLY WARM TEMPERATURES IN THE 30S AND 40S THROUGH THE NIGHT TONIGHT. GIVEN THE UNCERTAINTIES...THIS IS WHY I STUCK WITH THE CURRENT FORECAST. IF THERE IS A WINTRY MIX ACROSS PARTS OF EL PASO COUNTY TO KIOWA/PROWERS COUNTIES...THEN IT WILL BE SHORT-LIVED AS VIGOROUS SOUTH-SOUTHWEST LOWER TROP WINDS DEVELOP EARLY SATURDAY MORNING. 45-70KTS AROUND 800MB-700MB DEVELOPS ACROSS SOUTHEAST CO SATURDAY. POTENTIAL WIND GUSTS UP TO 60 MPH WILL BE LIKELY IF THE SURFACE PRESSURE GRADIENT CAN TIGHTEN LIKE THE GFS...BUT THE NAM-WRF IS A LITTLE WEAKER. SINCE IT WILL BE CLOSE...PLAN TO GO AHEAD WITH A HIGH WIND WARNING ACROSS SOUTHEAST CO PLAINS AND GOES WELL WITH ABQ/AMA WARNING. STILL A LITTLE CONCERNED ABOUT MAX TEMPERATURES ACROSS SOUTHEAST CO SATURDAY. WE ARE STILL ROUGHLY 10-15 DEGREES BELOW MOS GUIDANCE WITH DEEP VIGOROUS SOUTHWEST-WEST DOWNSLOPE FLOW. STAYED THE COURSE GIVEN SURROUNDING OFFICES. ONE FINAL POTENTIAL IMPACT ISSUE IS FIRE WEATHER CONCERNS GIVEN THE WINDY TO STRONG WIND CONDITIONS ACROSS THE SOUTHEAST CO PLAINS. FUELS ARE AT CRITICAL LEVELS ACROSS THIS AREA...TEMPERATURES WILL BE ABOVE AVERAGE READINGS...BUT HUMIDITY VALUES ARE NOT FORECAST TO BE BELOW 20 PERCENT. GIVEN THE COMPLEX WEATHER PATTERN ALREADY OCCURRING...WILL FORGO THE FIRE WEATHER HEADLINES. 17 LONG TERM... (SATURDAY NIGHT THROUGH FRIDAY) LATEST LONGER TERM MODELS INDICATE THAT UPPER SYSTEM CONTINUES TO IMPACT REGION FROM SATURDAY NIGHT INTO SUNDAY MORNING WITH IMPROVING METEOROLOGICAL CONDITIONS RETURNING TO THE CWFA FROM LATER SUNDAY INTO EARLY WEDNESDAY. ANOTHER UPPER SYSTEM IS PROJECTED TO BRING UNSETTLED WEATHER CONDITIONS TO THE AREA FROM WEDNESDAY INTO NEXT FRIDAY. FOR SENSIBLE WEATHER...HAVE PAINTED SNOW...HEAVY AT TIMES...TO CONTINUE OVER PORTIONS OF ZONES 58/59/60/61/68 AND 75 ON SATURDAY NIGHT WITH PRECIPITATION DECREASING SUNDAY. IN ADDITION...HAVE CONTINUED TO PAINT RELATIVELY STRONG WINDS OVER THE CWFA FROM SATURDAY NIGHT INTO AT LEAST SUNDAY MORNING. GENERALLY DRY AND WARMER CONDITIONS EXPECTED TO DEVELOP OVER THE REGION MONDAY AND TUESDAY WITH COOLER AND UNSETTLED CONDITIONS THEN RETURNING AGAIN TO SOUTHERN COLORADO FROM LATER WEDNESDAY INTO NEXT FRIDAY. AVIATION...BASED ON THE SHORT TERM DISCUSSION...THE PREVIOUS DISCUSSION LOOKS ON TARGET. MVFR CONDITIONS SHOULD DEVELOP AT THE THREE SITES FROM 00Z TO 02Z. KALS WILL SEE SOME LIGHT SNOW...AND KCOS SOME LIGHT SNOW...SLEET...THEN FREEZING RAIN AFTER 07Z. KPUB WILL LIKELY SEE PERIODS FOR RAIN...SLEET...SNOW...WITH A CHANCE OF A BRIEFLY PERIOD OF FREEZING RAIN FOR A FEW HOURS IN THE MIDDLE OF THE NIGHT. WINDY CONDITIONS WILL AFFECT ALL TAF LOCATIONS SATURDAY. TLM/17 PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ093>099. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MST SATURDAY FOR COZ084-085-095-096-098. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ067. && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MST SATURDAY FOR COZ058-059. HIGH WIND WARNING FROM 6 AM TO 6 PM MST SATURDAY FOR COZ093>099. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MST SATURDAY FOR COZ084-085-095-096-098. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST SATURDAY FOR COZ064. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ067. && $$ 10/28 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 221 PM MST FRI NOV 30 2007 .SHORT TERM... (TONIGHT AND SATURDAY) ...COMPLEX WEATHER PATTERN OVER THE NEXT 24-36 HOURS... ...FEET OF SNOW FOR THE SOUTHWEST/CENTRAL MOUNTAINS... ...WINTRY MIX STILL POSSIBLE PARTS OF SOUTHEAST CO TONIGHT... ...STRONG/DAMAGE HIGH WIND THREAT SOUTHEAST CO SATURDAY... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED THE OPENING SUB-TROPICAL WEATHER SYSTEM JUST OFF THE CA BAJA MOVING EAST THANKS TO AN UPPER LEVEL JET STREAM AND ASSOCIATED DIGGING TROUGH MOVING JUST OFF THE CA COAST. IN RETURN...VERY DEEP SOUTHWEST FLOW AND HIGH MOISTURE CONTENT AIR WAS STREAMING ACROSS OLD MEXICO...THE DESERT SOUTHWEST INTO UT/CO. 12Z/30 OBS SOUNDINGS ACROSS SOUTHERN CA...AZ...NM...AND SOUTHWEST TX HAD PRECIPITABLE WATER INDICES OF 150-315 PERCENT ABOVE NORMAL VALUES THIS TIME OF THE YEAR...1.19 INCHES AT TUCSON...AZ. 700MB-500MB SPECIFIC HUMIDITY VALUES ARE AROUND 5G/KG...WHICH IS A FAIRLY TROPICAL AIR MASS AND SOMETHING WE SEE AROUND HERE DURING THE SUMMER "MONSOON." GIVEN THE RELATIVELY STRONG MOISTURE TRANSPORT...BANDS OF SHOWERS HAVE BEEN FORMING ACROSS UT...WESTERN CO...AND NM. THERE HAS BEEN SOME PERIODIC SNOWFALL ACROSS THE HIGH TERRAIN PER SPOTTERS...OBS...AND LIVE WEBCAMS. WARM AIR ALOFT ALREADY BUILDING AS LA VETA PASS SENSOR STARTED IN THE 20S THIS MORNING AND MANAGED TO WARM INTO THE MIDDLE 30S DURING SOME PRECIPITATION. THE BOSQUE RAWS IN THE EAST SIDE THE SOUTHERN SANGRE DE CRISTO MOUNTAINS AROUND 8K FT MSL WAS IN THE LOWER 50S...GOTTA LOVE CO COMPLEX TERRAIN. WE RECEIVED A SPOTTER REPORT OF 1.5 INCHES OF SNOW 5 ESE FORT GARLAND(8500 FEET MSL) AND THAT WAS IN ABOUT 6 HOURS. EARLY THIS AFTERNOON...MOST LIVE WEBCAMS(WOLF CREEK PASS...MONARCH PASS...SAN LUIS VALLEY) LOOK RELATIVELY SNOWFALL-FREE. MEANWHILE...SHALLOW CP AIR MASS WAS ACROSS EASTERN CO INTO THE CENTRAL/SOUTHERN PLAINS. TEMPERATURES ARE STRUGGLING TO WARM IN THE LOWER AR RIVER VALLEY AND MAY NOT MAKE IT INTO THE 30S AROUND LAMAR. SURFACE WINDS WERE ALREADY VEERING TO THE SOUTH-SOUTHEAST ALONG I-25 CORRIDOR AND EASTWARD WITH DEW POINTS IN THE TEENS. FOR THE MOUNTAINS/HIGH VALLEYS LATE THIS AFTERNOON THROUGH SATURDAY...QUITE THE ARRAY OF WEATHER ACROSS MUCH OF CO GIVEN THE VERY COMPLEX AND CHALLENGING WEATHER PATTERN. GIVEN THE DEEP MOISTURE FLUX COMBINED WITH ISENTROPIC ASCENT TONIGHT AND OROGRAPHIC ASCENT FOR SOME FAVORED AREAS...SNOW SHOWERS SHOULD BECOME MORE STEADY SNOW...HEAVY AT TIMES...ACROSS THE MOUNTAINS AND HIGH VALLEYS ESPECIALLY FOR THE SAN JUAN...LA GARITA...COLLEGIATE... AND SANGRE DE CRISTO MOUNTAIN RANGES. STILL LOOKS LIKE THE HEAVIEST SNOW WILL BE GENERALLY ABOVE 8K FT MSL...ESPECIALLY AROUND THE MOUNTAIN PEAKS/HIGH MOUNTAIN PASSES. 1-4 FEET STILL LOOKS DOABLE AROUND THE CENTRAL AND SOUTHERN PORTION OF THE CONTINENTAL DIVIDE. LESSER AMOUNTS AS YOU HEAD TO THE LOWER ELEVATIONS. WENT AHEAD AND ADDED ADVISORIES FOR THE LOWER ELEVATIONS OF THE WEST SIDE OF THE CONTINENTAL DIVIDE IN SAGUACHE COUNTY/LA GARITA MOUNTAINS TOWARD THE GUNNISON VALLEY AND THE REST OF LAKE COUNTY INCLUDING LEADVILLE. OTHER LOWER MOUNTAIN VALLEY/HIGH VALLEYS LIKE SAN LUIS AND UPPER AR SHOULD SEE SOME ACCUMULATING LIGHT SNOW...BUT BELOW ADVISORY VALUES. THE SNOW LIKELY ENDS FOR THE SANGRE DE CRISTO/WET/PIKE PIKE MOUNTAINS GIVEN RELATIVELY STRONG ISENTROPIC DOWNGLIDE AS MODERATE-STRONG MIDLEVEL TO SURFACE WINDS DEVELOP. HOWEVER...OROGRAPHIC ASCENT DRIVEN SNOW SHOULD CONTINUE ACROSS THE CONTINENTAL DIVIDE. FOR THE I-25 CORRIDOR AND SOUTHEAST CO PLAINS LATE THIS AFTERNOON THROUGH SATURDAY...VERY TOUGH CALL IN WHAT WILL ACTUALLY OCCUR. STAYED CLOSE TO CURRENT FORECAST GIVEN A NUMBER OF UNCERTAINTIES. IN RESPONSE TO THE CP AIR MASS POSSIBLY RECEDING EASTERN CO AND WARM AIR ADVECTION ALOFT...SURFACE PRESSURE FALLS INCREASE THROUGH THE NIGHT. 295K/300K ISENTROPIC ASCENT DEVELOPS ACROSS MUCH OF NM...EASTERN CO...AND ESPECIALLY KS/OK/TX. TOUGH TO TRULY SAY WHERE THE WARM FRONT WILL BE LOCATED AS ANY PRECIPITATION EVAPORATIVE OR DIABATIC COOLING COULD KEEP THE SHALLOW COLD AIR LOCKED INTO THE LOWER AR RIVER VALLEY WHILE THE WARM AIR BUILDS OVER EASTERN CO. IF THAT IS THE CASE...THEN THERE STILL COULD BE A WINTRY MIX THIS EVENING AND OVERNIGHT GENERALLY EAST OF I-25 CORRIDOR AND NOT FOR THE RATON MESA OR PALMER DIVIDE GIVEN THE HIGHER TERRAIN. NAM-WRF 12KM SOUNDING FOR EADS HAS A FREEZING RAIN VERTICAL THERMAL PROFILE. HOWEVER...IF THE PRECIPITATION HAS TROUBLES MATERIALIZING...OR INCREASING IN INTENSITY...THEN THE WARM SOUTHERLY WIND COULD TAKE OVER. BOTH THE GFS AND NAM-WRF MOS GUIDANCE HAVE CONSISTENTLY WARM TEMPERATURES IN THE 30S AND 40S THROUGH THE NIGHT TONIGHT. GIVEN THE UNCERTAINTIES...THIS IS WHY I STUCK WITH THE CURRENT FORECAST. IF THERE IS A WINTRY MIX ACROSS PARTS OF EL PASO COUNTY TO KIOWA/PROWERS COUNTIES...THEN IT WILL BE SHORT-LIVED AS VIGOROUS SOUTH-SOUTHWEST LOWER TROP WINDS DEVELOP EARLY SATURDAY MORNING. 45-70KTS AROUND 800MB-700MB DEVELOPS ACROSS SOUTHEAST CO SATURDAY. POTENTIAL WIND GUSTS UP TO 60 MPH WILL BE LIKELY IF THE SURFACE PRESSURE GRADIENT CAN TIGHTEN LIKE THE GFS...BUT THE NAM-WRF IS A LITTLE WEAKER. SINCE IT WILL BE CLOSE...PLAN TO GO AHEAD WITH A HIGH WIND WARNING ACROSS SOUTHEAST CO PLAINS AND GOES WELL WITH ABQ/AMA WARNING. STILL A LITTLE CONCERNED ABOUT MAX TEMPERATURES ACROSS SOUTHEAST CO SATURDAY. WE ARE STILL ROUGHLY 10-15 DEGREES BELOW MOS GUIDANCE WITH DEEP VIGOROUS SOUTHWEST-WEST DOWNSLOPE FLOW. STAYED THE COURSE GIVEN SURROUNDING OFFICES. ONE FINAL POTENTIAL IMPACT ISSUE IS FIRE WEATHER CONCERNS GIVEN THE WINDY TO STRONG WIND CONDITIONS ACROSS THE SOUTHEAST CO PLAINS. FUELS ARE AT CRITICAL LEVELS ACROSS THIS AREA...TEMPERATURES WILL BE ABOVE AVERAGE READINGS...BUT HUMIDITY VALUES ARE NOT FORECAST TO BE BELOW 20 PERCENT. GIVEN THE COMPLEX WEATHER PATTERN ALREADY OCCURRING...WILL FORGO THE FIRE WEATHER HEADLINES. METZE .LONG TERM... (SATURDAY NIGHT THROUGH FRIDAY) LATEST LONGER TERM MODELS INDICATE THAT UPPER SYSTEM CONTINUES TO IMPACT REGION FROM SATURDAY NIGHT INTO SUNDAY MORNING WITH IMPROVING METEOROLOGICAL CONDITIONS RETURNING TO THE CWFA FROM LATER SUNDAY INTO EARLY WEDNESDAY. ANOTHER UPPER SYSTEM IS PROJECTED TO BRING UNSETTLED WEATHER CONDITIONS TO THE AREA FROM WEDNESDAY INTO NEXT FRIDAY. FOR SENSIBLE WEATHER...HAVE PAINTED SNOW...HEAVY AT TIMES...TO CONTINUE OVER PORTIONS OF ZONES 58/59/60/61/68 AND 75 ON SATURDAY NIGHT WITH PRECIPITATION DECREASING SUNDAY. IN ADDITION...HAVE CONTINUED TO PAINT RELATIVELY STRONG WINDS OVER THE CWFA FROM SATURDAY NIGHT INTO AT LEAST SUNDAY MORNING. GENERALLY DRY AND WARMER CONDITIONS EXPECTED TO DEVELOP OVER THE REGION MONDAY AND TUESDAY WITH COOLER AND UNSETTLED CONDITIONS THEN RETURNING AGAIN TO SOUTHERN COLORADO FROM LATER WEDNESDAY INTO NEXT FRIDAY. && .AVIATION...BASED ON THE SHORT TERM DISCUSSION...THE PREVIOUS DISCUSSION LOOKS ON TARGET. MVFR CONDITIONS SHOULD DEVELOP AT THE THREE SITES FROM 00Z TO 02Z. KALS WILL SEE SOME LIGHT SNOW...AND KCOS SOME LIGHT SNOW...SLEET...THEN FREEZING RAIN AFTER 07Z. KPUB WILL LIKELY SEE PERIODS FOR RAIN...SLEET...SNOW...WITH A CHANCE OF A BRIEFLY PERIOD OF FREEZING RAIN FOR A FEW HOURS IN THE MIDDLE OF THE NIGHT. WINDY CONDITIONS WILL AFFECT ALL TAF LOCATIONS SATURDAY. TLM/METZE && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ093>099. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MST SATURDAY FOR COZ084-085-095-096-098. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ067. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 640 PM EST FRI NOV 30 2007 .SYNOPSIS... AN ARCTIC COLD FRONTAL BOUNDARY WILL PASS THROUGH THE REGION TONIGHT...ALLOWING FOR A VERY COLD AIR MASS TO SETTLE INTO THE REGION FOR SATURDAY. MEANWHILE...LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY TONIGHT IN THE COLD AIR BEHIND THE FRONT. DRY WEATHER WILL DOMINATE THE REGION ON SATURDAY...BEFORE ANOTHER STORM SYSTEM APPROACHES THE GREAT LAKES ON SUNDAY. THIS STORM WILL SPREAD A VARIETY OF WINTER WEATHER ACROSS THE ENTIRE REGION AS IT REFORMS OFF THE NEW JERSEY SHORE BY MONDAY. && .NEAR TERM /THROUGH TONIGHT/... ARCTIC FRONT (NUMBER 1) IS PROGRESSING NICELY ACROSS WESTERN/CENTRAL NEW YORK WITH A NARROW BAND OF SNOW. WIND GUSTS UP TO 45KTS HAVE BEEN OBSERVED AT ROC WITH THE CONVECTION AND THIS IS A SIGN OF OUR FORECAST TONIGHT. LATEST 18Z RUN OF THE WRF AND RUC SHOW FROPA BETWEEN 00-03Z WITH THE NARROW BAND OF SNOW. BASED ON MESOSCALE FEATURES...THINK MID HUDSON VALLEY...NW CONNECTICUT AND PORTIONS OF THE BURKS AND SOUTHERN VT MAY NOT SEE MUCH IN THE WAY OF SNOW WITH SOME DOWNSLOPING AND BEST SUPPORT TRACKING NORTH. LAKE EFFECT SNOW WILL QUICKLY SET UP OFF LAKE ONTARIO WITH MODERATE-EXTREME INSTABILITY DEVELOPING. BUFKIT PROFILES FROM UCA AND SYR SHOW AN IMPRESSIVE STEEP LAPSE RATES AND A BAND OF SNOW DEVELOPING WITH TOP OF THE INVERSION NEAR 700MB! WITH TEMPERATURES AT THIS LEVEL FORECAST TO BE AT OR BELOW -20C...WOULD NOT BE SURPRISED TO SEE SOME THUNDER. WHILE ALWAYS PROBLEMATIC WITH QPF AMOUNTS...MODEL BLEND OF THE 12Z/18Z NAM12 AND RUC POINTS TOWARD ADVISORY CRITERIA FOR HERKIMER/FULTON AND SOUTHERN HAMILTON COUNTY (UPSLOPE CONDITIONS). THOUGHTS AT THIS TIME WILL BE 3-5 INCHES BUT COULD BE LOCALLY HIGHER IF BAND REMAINS NEARLY STATIONARY AND A GOOD CONVECTIVE BURST. FURTHERMORE...WIND FIELD WILL BE RATHER IMPRESSIVE WITH MIXING LAYER HEIGHTS TAPING INTO 40KT WINDS. THIS WOULD RESULT IN BLOWING AND DRIFTING OF THE SNOW...SO A COMBO OF LAKE EFFECT SNOW/BLOWING SNOW ADVISORY WILL BE HOISTED. TEMPERATURES WILL DROP RATHER QUICKLY THIS EVENING WITH OVERNIGHT LOWS AROUND 20F OR COLDER AS SECONDARY ARCTIC FRONT SLIDES SOUTH BY SUNRISE SATURDAY. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... METEOROLOGICAL WINTER BEGINS ON DECEMBER 1 (AS OPPOSED TO ASTRONOMICAL WINTER WHICH IS NOT FOR THREE WEEKS). EITHER WAY...DECEMBER WILL BE USHERED IN WITH THE COLDEST AIR MASS OF THE SEASON. THE ONLY PLACE WHERE TEMPS MIGHT GET ABOVE FREEZING WOULD BE THE MID HUDSON VALLEY...AND EVEN THERE IT MIGHT NOT HAPPEN. MOST OTHER AREAS WILL TOP OUT IN THE 20S...EXCEPT TEENS TO THE NORTHWEST OF ALBANY. WITH HIGH PRESSURE CRESTING JUST NORTH OF THE REGION SATURDAY NIGHT...TEMPERATURES WILL TUMBLE TO THE LOWEST READINGS SINCE EARLY LAST MARCH. EXPECT OVERNIGHT LOW READINGS TO APPROACH ZERO IN THE ADIRONDACKS...AND CLOSE TO 10 EVEN AS FAR SOUTH AS POUGHKEEPSIE. CLOUDS LOOK TO ARRIVE JUST IN TIME FOR SUNRISE SUNDAY. WITH A VERY COLD NIGHT FOLLOWED BY THE CLOUDS...WE ARE ASSURED THE COLD AIR INITIALLY WILL BE LOCKED IN PLACE...AS A STORM...FORECAST TO BUILD TO OUR SOUTHWEST...APPROACHES OUR REGION. DESPITE THE COLD AIR MASS...THE GFS/NAM AND EUROPEAN MODELS THUS FAR TAKE THE PRIMARY AREA OF LOW PRESSURE TO THE WEST OF OUR REGION...THROUGH THE SAINT LAWRENCE VALLEY. ALL OF THESE MODELS DO SHOW A SECONDARY LOW DEVELOPING ACROSS THE EASTERN MID ATLANTIC MOVING NORTHEAST OFF OF LONG ISLAND CAPE COD AND THE GULF OF MAINE BY LATE MONDAY. THE GFS (SUPPORTED BY THE EUROPEAN) HAS CONSISTENTLY INDICATED ABOUT AN INCH OR MORE QPF FOR OUR ENTIRE REGION AND WAS THE PREFERRED MODEL TO USE. THE 12Z GFS DID TREND A LITTLE COLDER THAN THE LAST RUN...WHICH HAS BEEN THE TREND FOR THE PAST COUPLE OF DAYS. THE STORM IS STILL SEVERAL THOUSAND MILES AWAY...AND WILL CONSIST OF THREE DISTINCT SHORT WAVES....ONE DIVING SOUTH OFF THE NORTHWEST COAST...ANOTHER OVER SOUTHERN CALIFORNIA...AND THE THIRD COMING OUT OF OLD MEXICO. IN THE NEXT DAY...THESE WAVES ARE FORECAST TO MERGE INTO ONE LARGE STORM TRACKING ACROSS THE NATIONS HEARTLAND...NORTHWARD TO MICHIGAN. AT THAT POINT...THE STORM HITS A LOT OF COLD AIR...AND IS FORCED TO MAKE A MORE EASTERLY TRACK INTO THE SAINT LAWRENCE VALLEY...AS LOTS OF VORTICITY SPUN OFF FROM THE SYSTEM...FORM A NEW LOW PRESSURE OFF THE MID ATLANTIC. WHILE IT IS TOO PREMATURE TO REALLY ATTEMPT TO PINPOINT PTYPES AND AMOUNTS AND EVEN TIMING OF PRECIPITATION...WE FEEL THAT THERE IS ENOUGH POTENTIAL FOR A SIGNIFICANT WINTER STORM TO IMPACT MUCH...IF NOT ALL OF OUR CWA...AND THEREFORE LAUNCHED A WINTER STORM WATCH FOR THE ENTIRE AREA. DRY AIR...STILL ADVECTING INTO THE REGION EARLY SUNDAY...MIGHT DRY OUT THE INITIAL WARM AIR ADVECTION THRUST OF SNOW. HOWEVER...WITH TIME...THE COLUMN SHOULD SATURATE SOMETIME BY LATE IN THE DAY. AT THIS POINT...IT STILL LOOKS COLD ENOUGH FOR MOSTLY SNOW TO FALL. THEN...THE BRUNT OF ISENTROPIC LIFT WILL OVERSPREAD THE REGION SUNDAY NIGHT AND THIS IS WHEN THE BIGGEST CHALLENGE FOR PTYPES TAKES PLACE. FOR NOW...WENT WITH MOSTLY SNOW NORTH OF ALBANY (WHERE OVER A FOOT COULD FALL)...AND MOSTLY MIXED PRECIPITATION SOUTH OF ALBANY. WE KEPT TEMPS AT OR BELOW FREEZING THROUGH THE NIGHT. WE ARE CONCERNED THAT FOLKS TO OUR SOUTH COULD HAVE A SIGNIFICANT ICING EVENT. AS THE SECONDARY STORM GETS GOING ON MONDAY...COLD AIR WILL RETURN AT ALL LEVELS OF THE COLUMN...CHANGING ANY LEFTOVER PRECIPITATION TO SNOW. THE GFS/NAM PRODUCE A TROAL OVER INTERIOR NEW ENGLAND...WHERE MODERATE OR EVEN HEAVY SNOW COULD PERSIST. THE 18Z NAM HAD THIS FEATURE CLOSE TO OUR REGION. THE BOTTOM LINE...SNOW WILL PERSIST INTO AT LEAST THE FIRST HALF OF MONDAY...PERHAPS EVEN LONGER. AS THE FLOW TURNS NW AND QUITE BRISKLY...LAKE EFFECT SNOW OFF LAKE ONTARIO WILL LIKELY KICK AND IT COULD BE ROBUST INTO TUESDAY. && .LONG TERM /TUESDAY THROUGH FRIDAY/... IN THE WAKE OF THE FIRST REAL WINTER STORM...ANOTHER SURGE OF ARCTIC AIR WILL COME PLUNGING ALONG WITH CONTINUED WIND. THE LAKE GUNS WILL BE GOING STRONG...AT LEAST EARLY IN THE DAY. AS THE FLOW BECOMES MORE ANTICYCLONIC...THEY WILL ABATE BY LATE. FROM THIS VANTAGE POINT...IT APPEARS THAT MOST LAKE EFFECT SNOW ON TUESDAY SHOULD BE CONFINED TO WESTERN PORTIONS OF OUR MOHAWK VALLEY...ADIRONDACKS AND CATSKILLS. A LITTLE BREAK IN THE ACTION FOLLOWS WEDNESDAY WITH A MAINLY DRY BUT CONTINUED COLD DAY. THEN...IT LOOKS AS IF ANOTHER POTENT CLIPPER TYPE STORM WILL DIVE TO OUR SOUTH...AND POSSIBLY TAP INTO ATLANTIC OCEAN MOISTURE. THIS IS WHAT THE 12Z GFS FORECAST THIS SYSTEM TO DO. THE SECONDARY STORM WILL TRACK NORTH FROM THE MID ATLANTIC REGION...NORTHWARD TO OFF CAPE COD BY LATER THURSDAY. THIS COULD BRING A MODEST SNOWFALL (AT THE VERY LEAST) TO OUR PARTS LATE WED INTO THUR. AFTER THAT...MORE COLD AIR IS FORECAST TO COME ON THE HEELS OF THIS STORM VIA NW WINDS. THIS COULD YIELD ANOTHER ROUND OF LAKE EFFECT SNOW AND CERTAINLY A CONTINUATION OF BELOW SEASONABLE TEMPERATURES THROUGH NEXT FRIDAY. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR FLIGHT CONDITIONS WILL PREVAIL OVER MOST OF THE FORECAST AREA TONIGHT...WITH MVFR/IFR CEILINGS AND VISIBILITY OVER THE MOHAWK VALLEY AND WESTERN ADIRONDACKS DUE TO LAKE EFFECT SNOW SHOWERS AND SQUALLS. SOUTHERLY WINDS AHEAD OF A COLD FRONT WILL SHIFT TO WEST AND NORTHWEST BETWEEN 00Z AND 06Z. DURING THE NIGHT WEST TO NORTHWEST WINDS WILL INCREASE TO AROUND 15 KNOTS AND GUST TO AS HIGH AS 30 KNOTS...ESPECIALLY DOWN THE MOHAWK VALLEY FROM ROME EAST TO ALBANY WHERE THE TERRAIN WILL HAVE A FUNNELING EFFECT. CONDITIONS ARE LIKELY TO WORSEN AS ONE GOES WEST FROM ALBANY TOWARD LAKE ONTARIO. IFR AND LIFR CONDITIONS MAY BE ENCOUNTERED FROM TIME TO TIME IN SNOW SQUALLS WITH NEAR ZERO VISIBILITY. THE ALBANY AREA MAY EXPERIENCE A FEW BRIEF SNOW SHOWERS OR FLURRIES...BUT THE PROBABILITY OF LOWERING FLIGHT CONDITIONS TO MVFR IS LOW ENOUGH THAT WE HAVE SIMPLY INDICATED VCSH IN THE ALBANY AND GLENS FALLS TAFS. SNOW SHOWERS ARE NOT EXPECTED IN THE HUDSON VALLEY SOUTH OF KINGSTON DUE TO THE DOWNSLOPING EFFECT OF THE CATSKILLS. AHEAD OF THE FRONT...LOW LEVEL WIND SHEAR MAY BE EXPERIENCED WITH A QUICK SHIFT FROM SOUTHERLY WINDS NEAR THE SURFACE TO SOUTH WEST TO WEST 35 TO 40 KNOTS AROUND 3000 TO 4000 FEET ABOVE SEA LEVEL. GUSTY WINDS WILL PERSIST INTO SATURDAY MORNING...THEN GRADUALLY SUBSIDE LATE IN THE AFTERNOON. NO FURTHER AVIATION WEATHER RELATED PROBLEMS ARE EXPECTED THROUGH SATURDAY NIGHT. AS WE HEAD INTO SUNDAY...THE SEASON`S FIRST WINTER STORM IS LIKELY TO IMPACT THE AREA WITH A WINTERY MIX OF SNOW...SLEET... AND RAIN. OUTLOOK... SAT...VFR...LOCAL MVFR IN SCT SNOW SHOWERS. SUN...VFR DETERIORATING TO IFR BY LATE IN THE DAY DUE TO SNOW OR A WINTRY MIX. MON...IFR IMPROVING TO VFR. LINGERING AM SNOW/WINTRY MIX. TUE...VFR...POSSIBLE MVFR IN ISLD SHSN. WED...VFR...SLIGHT CHC OF SHSN. && .HYDROLOGY... NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH SUNDAY. LAKE EFFECT SNOWFALL WILL IMPACT THE WRN ADIRONDACKS AND MOHAWK VALLEY TONIGHT INTO SATURDAY. A COMPLEX STORM SYSTEM WILL BRING POTENTIALLY A VARIETY OF PTYPES TO THE FCST AREA SUNDAY THROUGH MONDAY. THE GREATEST IMPACT LOOKS TO BE SUNDAY NIGHT INTO MONDAY MORNING. TOTAL QPF FROM THE EVENT LOOKS TO BE A HALF AN INCH TO AN INCH AND A QUARTER. SHOULD THE PRECIPITATION FALL AS MAINLY LIQUID...AREAS THAT COULD BE SUSCEPTIBLE TO FLOODING CONCERNS WOULD INCLUDE PORTIONS OF THE UPPER MOHAWK BASIN ABOVE LITTLE FALLS...INCLUDING THE WEST AND EAST CANADA CREEKS...AS WELL AS THE SCHOHARIE BASIN. HOWEVER...THIS THREAT WOULD BE GREATLY REDUCED SHOULD MORE FROZEN PRECIPITATION OCCUR. AFTER MONDAY...NO HYDRO CONCERNS ANTICIPATED AT THIS TIME. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR CTZ001-013. NY...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR NYZ032-033-038>043-047>054-058>061-063>066- 082>084. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST SATURDAY FOR NYZ032-033-038-039-082. MA...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR MAZ001-025. VT...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR VTZ013>015. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...HWJIV LONG TERM...HWJIV AVIATION...RCK HYDROLOGY...BGM ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 845 PM EST FRI NOV 30 2007 .UPDATE...WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORTWAVE TROUGH MOVING THROUGH THE FORECAST AREA WITH CIRRUS SHIELD NOW IN THE SE PORTION OF AREA. MODELS SHOW THE TROUGH WILL CONTINUE PUSHING SEWD WITH AN UPPER LEVEL HIGH PRESSURE RIDGE MOVING INTO THE GOMEX THROUGH SATURDAY. AT SFC...LARGE HIGH PRESSURE RIDGE IS CENTERED FROM MID MS VALLEY TO TN THEN OVER TO NC AND ERN VA. N TO NE FLOW REGIME SEEN IN THE OBSERVATIONS AND LIGHTER WINDS AND MOIST ATMOSPHERE UP TO 900 MB PER 00Z SOUNDING IS ALREADY RESULTING IN FOG DEVELOPMENT. A FEW REPORTS OF MVFR VIS RECEIVED MAINLY S OF JAX AND E OF GNV WHERE BOUNDARY LAYER MOISTURE IS HIGHEST. FOG PRODUCT ALSO SHOWS STRATO-CU OVER EXTREME S ZONES AND THINK BY IN LARGE PART THAT THIS WILL BE SHORT-LIVED AS MID LEVEL TROUGHING OVER THIS AREA SHIFTS SWD OVERNIGHT. HOWEVER...SOME LOW STRATUS WILL BE POSSIBLE IN THESE AREAS (MAINLY S OF GAINESVILLE) WHERE MOISTURE DEPTH WILL BE MAINTAINED UP THROUGH ABOUT 500-1000 FT. HAVE TWEAKED TEMPS DOWN A DEGREE OR SO WITH SOME OF THE THICKER HIGH CLOUDS MOVING OUT...BUT STILL APPEARS SOME THIN HIGH CLOUDS WILL MOVING INTO NRN ZONES AS THEY SPILL OVER THE UPPER LEVEL RIDGE BY EARLY SATURDAY MORNING. && .AVIATION...EXPECT VSBYS 3-5 SM BR WITH A LOT OF LOW LEVEL MOISTURE ACROSS THE AREA. SURFACE WINDS OF 3-7 KTS SHOULD KEEP LOW LEVELS MIXED ENOUGH...SO MAIN CONCERN WILL BE AREAS OF LOW STRATUS DEVELOPING. MOST FAVORED LOCATION FOR LOW STRATUS WILL BE INLAND FL. HAVE INDICATED TEMPO IFR DUE TO CIGS AND BR AT GNV AND JAX AFTER 09Z. && .MARINE...HURRAY! BUOY 41012 WAVES ARE BEING REPORTED ONCE AGAIN. NLY WINDS 15-20 KTS WITH GUSTS UP TO 23 KTS HAVE BEEN REPORTED OVER OFFSHORE LEGS THIS EVENING WITH COMBINED SEAS 3-4 FT. BASED ON 00Z INITIALIZATION...NAM12 DOING BETTER AS IS RUC WITH SHORT-TERM WIND SURGE SO HAVE BLENDED IT MORE INTO THE FORECAST. SCA STILL EXPECTED OFFSHORE LATER TONIGHT AS HIGH PRESSURE WEDGES INTO THE AREA AND TROUGHING LINGERS OFFSHORE. NEARSHORE WINDS ARE NEAR 15 KTS AT SAUF1 AND EXPECT NLY SURGE WILL RAISE SCEC FOR THESE LEGS LATER TONIGHT SO WILL INCLUDE HEADLINE IN NEXT CWF PACKAGE. && .PRELIMINARY POINT TEMPS/POPS... AMG 45 70 48 76 / 0 0 0 0 SSI 52 66 60 74 / 10 10 10 10 JAX 52 71 56 79 / 0 10 10 0 SGJ 58 72 62 77 / 10 10 10 10 GNV 53 76 55 81 / 0 0 0 0 OCF 56 78 56 81 / 10 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...SMALL CRAFT ADVISORY FROM 5 AM SATURDAY TO 7 AM EST SUNDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. && $$ SHASHY/ENYEDI/WALKER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 305 AM EST FRI NOV 30 2007 .SYNOPSIS... 08Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING A RATHER UNAMPLIFIED UPPER PATTERN ACROSS THE CONUS FOR THE END OF NOVEMBER. FLOW IS CHARACTERIZED BY A STRONG ZONAL BELT RUNNING FROM NORTHERN CALIFORNIA EASTWARD ACROSS THE MID-SECTION OF THE COUNTY AND INTO THE SOUTHERN GREAT LAKES AND MID-ATLANTIC. THIS STRONG BELT OF WESTERLIES IS RUNNING UNDERNEATH A WELL DEFINED POLAR VORTEX STILL SPINNING JUST TO THE WEST OF JAMES BAY CANADA. A SERIES OF SHORTWAVE TROUGHS ARE ROTATING AROUND THIS POLAR VORTEX. THE LATEST OF THESE SHORTWAVES TO EFFECT THE CONUS IS NOW MOVING AROUND THE SOUTHWEST PERIPHERY OF THE VORTEX INTO THE NORTHERN PLAINS AND NORTHERN GREAT LAKES. CLOSER TO HOME WE SEE WEAKER ZONAL FLOW ALONG THE GULF COAST OVER-TOP OF A BUILDING RIDGE ACROSS THE CENTRAL GOMEX. AT THE SURFACE...THE WEAK "COLD FRONT" CONTINUES TO PASS SOUTHEAST THROUGH OUR FORECAST AREA...ALTHOUGH IT HAS BECOME VERY DIFFICULT TO DETERMINE THE FRONTS EXACT LOCATION AS IT BEGINS TO WASH OUT. THE SMALL AMOUNT OF MIXING ASSOCIATED WITH THE FRONT HELPED TO SCOUR OUR THE LOWER CLOUDS FOR THE PAST EVENING WITH SKIES ACTUALLY GOING MOSTLY CLEAR IN MANY LOCATIONS. HOWEVER...THE LACK OF DRY AIR ADVECTION BEHIND THE FRONT IS KEEPING LOW LEVELS RATHER MOIST. 00Z KTLH SOUNDING SHOWED THIS LOWER LEVEL MOISTURE STILL TRAPPED UNDER A MUCH DRIER COLUMN ABOVE 900MB. COMBINED WITH THE WEAK FLOW...THIS IS A RECIPE FOR FOG AND LOW STRATUS DEVELOPMENT (GENERALLY EAST OF THE APALACHICOLA RIVER)...AND SURFACE OBS / 11U-3.9U SATELLITE IMAGERY ARE SHOWING EXPANDING AREAS OF LOW STRATUS AND FOG THIS EARLY MORNING. DESPITE THE COLD FRONTAL PASSAGE TEMPS SHOULD STAY GENERALLY ABOVE AVERAGE THE REST OF THE NIGHT WITH MIDDLE 40S TO 50S COMMON. THESE TEMPS SHOULD NOT FEEL THAT BAD WHEN COMPARED TO WHAT OTHER PARTS OF THE CONUS ARE SEEING THIS MORNING. FOR EXAMPLE...THE NORTHERN PLAINS AND NORTHERN MISSISSIPPI VALLEY WHICH ARE CLOSER TO THE POLAR VORTEX DISCUSSED ABOVE ARE SEEING TEMPS PLUMMETING BELOW ZERO...BRRR. && .SHORT TERM (TODAY-SUNDAY NIGHT)... PLEASANT DAY ON TAP FOR THE LAST DAY OF NOVEMBER AS HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY HOLDS CONTROL OF OUR WEATHER WHILE SLOWLY SLIDING EASTWARD. SOME PATCHES OF LOW STRATUS/AND OR FOG WILL BE AROUND FOR THE EASTERN HALF OF THE AREA DURING THE FIRST PART OF THE MORNING. THIS STRATUS MAY TAKE SOME TIME TO BURN OFF WITH THE SUN STRENGTH GETTING CLOSE TO ITS ANNUAL MINIMUM. HOWEVER...THINK MOST LOCATIONS WILL BE PARTLY TO MOSTLY SUNNY BY THE LATER MORNING HOUR AND ALL FOR THE AFTERNOON. AIRMASS IS STILL RATHER WARM AND EXPECTING HIGH TEMPS TO REACH A FEW DEGREES ABOVE CLIMO WITH GENERALLY LOWER 70S NORTH AND LOWER TO MIDDLE 70S SOUTH. MID/UPPER LEVEL RIDGING BEGINS TO BUILD NORTH FROM THE GULF OF MEXICO TONIGHT. SKIES SHOULD BE MOSTLY CLEAR AND WINDS LIGHT... HOWEVER WITH THE AIRMASS STILL FAIRLY WARM...RADIATIONAL COOLING WILL ONLY BE ABLE TO ACCOMPLISH SO MUCH. DID GO A COUPLE OF DEGREES BELOW GUIDANCE IN THE NORMALLY COOLER SPOTS BUT THIS ONLY BRINGS TEMPS DOWN TO RIGHT ABOUT CLIMO WITH MIDDLE 40S INLAND AND UPPER 40S TO NEAR 50 AT THE COAST. ANOTHER VERY PLEASANT DAY EXPECTED ON SATURDAY WITH SURFACE AND UPPER LEVEL RIDGING IN PLACE AND THE COLUMN CONTINUING TO WARM. ANOTHER AFTERNOON WITH TEMPERATURES SEVERAL DEGREES ABOVE CLIMO IS LIKELY. MOST LOCATIONS ARE ANTICIPATED TO REACH THE LOWER AND MIDDLE 70S WITH A FEW WARMER PLACES OVER THE EASTERN BIG BEND FLIRTING WITH THE UPPER 70S. WINDS BEGINNING THE DAY FROM THE NORTHEAST WILL SWING AROUND TO THE EAST AND SOUTHEAST FOR THE AFTERNOON. FOR THIS REASON...LOCATIONS ALONG THE COAST FROM WAKULLA COUNTY WESTWARD THROUGH THE EASTERN PANHANDLE ARE FORECAST TO STAY A BIT COOLER. THESE AREAS WILL LIKELY SEE HIGH TEMPS IN THE LOWER 70S TOWARD THE MIDDAY HOUR...BUT THEN FALL BACK INTO THE UPPER 60S AS WINDS PASS OVER THE COOLER SHELF WATERS THAT ARE CURRENTLY IN THE MIDDLE TO UPPER 60S. HIGH PRESSURE PUSHES TO THE ATLANTIC COAST SATURDAY NIGHT AS UPPER TROUGHING AND ASSOCIATED SURFACE FRONT MOVES INTO THE MISSISSIPPI VALLEY. THIS WILL CONTINUE TO VEER WIND MORE TO THE SOUTHEAST THROUGH THE NIGHT. THE RESULT WILL BE A CONTINUED INCREASE IN LOW LEVEL MOISTURE FROM THE GOMEX AND ABOVE NORMAL TEMPERATURES IN THE LOWER TO MIDDLE 50S FOR MOST LOCATIONS. AREAS ALONG THE COAST FROM FRANKLIN COUNTY WESTWARD MAY HAVE A HARD TIME EVEN FALLING BELOW 60F. COOLEST TEMPS IN THE UPPER 40S TO LOWER 50S WILL BE FOUND ACROSS INLAND SECTION OF THE EASTERN BIG BEND AND SOUTH-CENTRAL GA WHERE THE LEAST INFLUENCE FROM THE GOMEX WILL BE FELT. COLD FRONT APPROACHES FROM THE NORTHWEST SUNDAY AND CROSSES THE AREA SUNDAY NIGHT INTO EARLY MONDAY. WILL NOT FEEL LIKE EARLY DECEMBER ON SUNDAY WITH TEMPERATURES IN THE 70S AND DEWPOINTS RISING INTO THE 60S MOST PLACES. A FEW WARMER SPOTS ACROSS THE EASTERN BIG BEND MAY EVEN TOUCH 80F. RECORD HIGHS ON SUNDAY ARE IN THE LOWER 80S AND AT THIS TIME THESE SEEM SAFE. CLOUDS WILL BE ON THE INCREASE THOUGH... ESPECIALLY ACROSS THE WEST. SREF ENSEMBLES CONTINUE TO INSIST ON A SLIGHT CHANCE OF SHOWERS OVER SOUTHEAST ALABAMA DURING THE DAY...BUT WILL KEEP POPS BELOW 20 PERCENT FOR NOW. BEST CHANCE FOR QPF FOR ALL AREA WILL BE SUNDAY NIGHT WITH THE FRONTAL PASSAGE. MAIN SHORTWAVE ENERGY AND DYNAMICS LOOK TO PASS TO OUR NORTH DURING THE NIGHT SO WILL BE FORECASTING A WEAKENING LINE OF SHOWERS/STORMS FOR OUR AREA. && .LONG TERM (MONDAY-FRIDAY)... THE 00 UTC GFS AND ECMWF CONTINUE TO FORECAST A BREAKDOWN OF THE 500 MB RIDGE OVER THE EASTERN U.S. ON SUNDAY AS A LONG WAVE TROUGH BECOMES ESTABLISHED OVER THE EAST EARLY NEXT WEEK. THEY BOTH HAVE A COLD FRONT PASSING THROUGH OUR AREA LATE SUNDAY NIGHT OR EARLY MONDAY MORNING...WITH THE ECMWF BEING THE FASTEST SOLUTION. THE RAIN BAND ASSOCIATED WITH THIS FRONT WILL BE LOSING A LOT OF ITS DEEP LAYER MOISTURE AND Q-G FORCING AS IT MOVES SOUTHEAST ACROSS OUR AREA...AND THE POPS REMAIN IN THE 30 TO 50 PERCENT RANGE...WITH THE HIGHER POP AROUND DOTHAN AND THE LOWER POP AROUND CROSS CITY. THE GFS MOS IS BEGINNING TO LOCK ON TO A COLDER SCENARIO FOR OUR AREA TUESDAY MORNING...AS HAS BEEN INDICATED BY THE BIAS CORRECTED GFS FOR A FEW DAYS NOW. THIS MAKES SENSE GIVEN THE VERY DRY TROPOSPHERE THAT WILL BE IN PLACE...AS WELL AS THE SURFACE WINDS GOING NEAR CALM TOWARD DAYBREAK TUESDAY AS A RIDGE NOSES INTO THE AREA ALONG THE GULF COAST. TEMPERATURES COULD APPROACH THE FREEZING MARK IN A FEW OF THE NORMALLY COLDER INLAND LOCATIONS. LATER NEXT WEEK THE MODELS BEGIN TO DIVERGE IN THEIR HANDLING OF THE LARGE SCALE PATTERN. THE ECMWF BRINGS A SHORT WAVE TROUGH (AND AN AREA OF MOISTURE/QPF) THROUGH OUR AREA WHILE THE GFS MAINTAINS DEEP LAYER RIDGING. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS...BUT THE UNCERTAINTY THIS FAR OUT IS QUITE HIGH. && .AVIATION... AN AREA OF STRATOCU HAS DEVELOPED BETWEEN 2.5K AND 3.5K FT...JUST EAST OF A QUASI-STATIONARY FRONT ALONG THE APALACHICOLA/CHATAHOOCHEE RIVER. THIS FAIRLY NARROW CLOUD BAND HAS BEEN MOVING TOWARD THE EAST AND HAS BEEN INHIBITING DENSE FOG FORMATION IN WHAT WOULD OTHERWISE BE A FAVORABLE ENVIRONMENT. WE THINK THE VIS WILL DROP QUICKLY TO IFR OR EVEN VLIFR LEVELS WHEN (IF) THE BACK EDGE OF THIS CLOUD DECK CLEARS THE REGION. PREVAILING VFR CONDITIONS ARE FORECAST FOR KPFN...KDHN...AND KABY SINCE THESE SITES ARE BEHIND THE FRONT AND WILL EXPERIENCE WEAK DRY AIR ADVECTION. VIS/CIGS WILL IMPROVE BY MID TO LATE MORNING AT KVLD AND KTLH...FOLLOWED BY VFR CONDITIONS. WINDS WILL GENERALLY BE 6 KT OR LESS OUT OF THE NNE. && .MARINE... HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY THIS MORNING WILL SLIDE EAST THROUGH THE UPCOMING WEEKEND BUT REMAIN IN CONTROL OF THE FORECAST WATERS. NORTHEAST FLOW WILL REMAIN BELOW CAUTION LEVELS THROUGH THE DAYLIGHT HOURS TODAY. AS WINDS VEER MORE EASTERLY TONIGHT...DO EXPECT SPEEDS TO PICK UP TO NEAR CAUTION LEVELS AND LINGER INTO SATURDAY MORNING. ANOTHER PERIOD OF NEAR CAUTIONARY WINDS FROM THE SOUTHEAST IS POSSIBLE SATURDAY NIGHT. FLOW WILL THEN VEER TO THE SOUTH AND SOUTHWEST SUNDAY AND SUNDAY NIGHT AHEAD OF AN APPROCHING FRONT. THE FRONT IS SCHEDULED TO CROSS THE WATERS MONDAY MORNING AND AT THIS TIME LOOKS TO HAVE A RATHER STRONG SURGE OF NORTHERLY WINDS BEHIND IT FOR THE FIRST PART OF NEXT WEEK. && .FIRE WEATHER... SURFACE HIGH CENTERED WELL TO OUR NORTH WILL SLIDE EAST TOWARD THE EASTERN SEABOARD THROUGH SATURDAY WHILE CONTINUING TO CONTROL OUR WEATHER. NORTHERLY FLOW TODAY WILL SLOWLY COME AROUND TO THE NORTHEAST AND EVENTUALLY EAST ON SATURDAY AS THE RIDGE AXIS MOVES EAST. DESPITE ABOVE AVERAGE TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE 70S FRIDAY AND SATURDAY...LOW LEVEL MOISTURE IS EXPECTED TO REMAIN HIGH ENOUGH TO KEEP RH VALUES GENERALLY ABOVE CRITICAL LEVELS. MAY SEE RH VALUES TOUCH 35 PERCENT FOR AN HOUR THIS AFTERNOON ACROSS INLAND PORTIONS OF THE EASTERN FL PANHANDLE... HOWEVER CRITICAL DURATIONS ARE CERTAINLY NOT ANTICIPATED. A SIGNIFICANT INCREASE IN LOW LEVEL MOISTURE IS EXPECTED ON SUNDAY AHEAD OF COLD FRONT THAT SHOULD PASS THROUGH THE REGION SUNDAY NIGHT OR EARLY MONDAY. A SHOWER OR THUNDERSTORM IS ALSO POSSIBLE AT THIS TIME. FIRE WX CONCERNS MAY COME BACK INTO THE FORECAST MONDAY OR TUESDAY AFTERNOON AS MUCH DRIER AIR MOVES SOUTH BEHIND THIS NEXT FRONT. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 74 46 74 53 77 / 0 0 0 10 05 PANAMA CITY 72 49 72 59 75 / 0 0 0 10 10 DOTHAN 71 46 72 53 75 / 0 0 0 10 20 ALBANY 72 44 73 51 76 / 0 0 0 10 10 VALDOSTA 73 46 74 50 78 / 0 0 0 10 0 CROSS CITY 76 52 77 51 79 / 0 0 0 10 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ AVIATION/LONG TERM...FOURNIER PUBLIC/MARINE/FIRE WX...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 240 AM EST THU NOV 29 2007 .SYNOPSIS... 07Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING THE CONUS DOMINATED BY NORTHERN STREAM FLOW. STARTING IN THE EAST WE SEE WEAK RIDGING FROM THE MID-ATLANTIC STATES INTO SOUTHEAST CANADA. THIS RIDGING IS EXITING RAPIDLY EASTWARD AS UPSTREAM TROUGHING EXITS THE CENTRAL PLAINS TOWARD THE MIDDLE/NORTHERN MISSISSIPPI VALLEY. THIS TROUGHING IS ANCHORED BY A FAIRLY STRONG POLAR VORTEX SPINNING JUST TO THE WEST OF JAMES BAY CANADA. FINALLY FOR THE CONUS WE SEE ANOTHER IN A SERIES OF SHORTWAVE TROUGHS MOVING RAPIDLY ASHORE ALONG THE PACIFIC NORTHWEST COAST. THE LARGE CUTOFF LOW SEEN 24 HOURS AGO OFF THE BAJA COAST HAS CHANGED LITTLE IN POSITION AND CONTINUES TO PROPEL PLENTY OF MID/UPPER LEVEL MOISTURE NORTHWARD ALONG THE WEST COAST OF MEXICO INTO THE SOUTHWESTERN STATES. AT THE SURFACE...HIGH PRESSURE TO OUR NORTHEAST IS WEAKENING AND PUSHING EAST IN RESPONSE TO THE UPPER TROUGHING OVER THE MIDDLE SECTION OF THE COUNTY. A WEAK COLD FRONT IS NOW LOCATED FROM THE WESTERN TENNESSEE VALLEY SOUTHWARD INTO THE LOWER MISSISSIPPI VALLEY. MOVEMENT OF THE FRONT HAS BEEN A LITTLE BIT SLOWER THAN PREVIOUSLY THOUGHT AND IS NOW ANTICIPATED TO PUSH THROUGH THE FORECAST AREA DURING THE LATE MORNING AND AFTERNOON HOURS. ABUNDANT LOW LEVEL MOISTURE HAS ADVECTED INTO THE AREA ON EASTERLY FLOW DURING THE PAST 12-18 HOURS. THIS LOW LEVEL (950MB-850MB) MOISTURE UNDERNEATH VERY DRY MID-LEVELS (>800MB) PER 00Z KTLH SOUNDING IS A GOOD SETUP FOR CONTINUED LOW STRATUS ACROSS THE AREA AND WILL HOLD THESE LOWER CLOUDS (GENERALLY MVFR) FOR ALL AVIATION TERMINALS INTO AT LEAST THE FIRST PART OF THE MORNING. REGIONAL RADARS ARE SHOWING A FEW SHOWERS MOVING ASHORE FROM APALACHEE BAY INTO PORTIONS OF THE BIG BEND AND SOUTH-CENTRAL GA. THESE SHOWERS ARE THE RESULT OF SOME WEAK ISENTROPIC LIFT COMBINING WITH VERY LOW CONDENSATION PRESSURE DEFICITS (15-30MB) AROUND THE 300K SURFACE. BOTH NAM AND GFS SHOW THE BEST ISENTROPIC LIFT EXITING TO THE EAST THIS MORNING AND WILL END POPS/SHOWERS FROM WEST TO EAST OVER THE BIG BEND THROUGH THE MORNING AS WELL. && .SHORT TERM (TODAY-FRIDAY NIGHT)... WILL BE WAITING FOR A WEAK COLD FRONT TO CROSS THE FORECAST AREA FROM NORTHWEST TO SOUTHEAST LATER THIS MORNING INTO THE AFTERNOON HOURS. THIS FRONT WILL PASS THROUGH WITH LITTLE FAN FARE OTHER THAN A WIND SHIFT TO THE NORTHWEST AS THE COLUMN ABOVE AROUND 800MB IS EXTREMELY DRY AND WILL HOLD BACK THE POTENTIAL FOR ANY QPF. THE FRONT WILL SLOWLY BEGIN TO SCOUR OUT THE LOW LEVEL MOISTURE THAT IS RESULTING IN THE STRATUS DECK EARLY THIS MORNING. HOWEVER...AS MENTIONED ABOVE THE FRONT IS A BIT DELAYED FROM EARLY THINKING AND CLOUDS WILL BE HOLDING AROUND LONGER TODAY...ESPECIALLY FOR THE SOUTHEASTERN HALF OF THE AREA WHERE SIGNIFICANT CLEARING MAY HOLD OFF UNTIL THIS EVENING OR TONIGHT. EXPECTING ANY LINGERING SHOWERS/SPRINKLES OVER THE EASTERN BIG BEND (DISCUSSED IN THE SYNOPSIS) TO END DURING THE MORNING HOURS AS BEST ISENTROPIC LIFT DYNAMICS PUSH EAST AND WEAKEN. TEMPERATURES ARE GOING TO BE RATHER TRICKY TODAY WITH THE SLOWLY DEPARTING LOWER CLOUDS. CERTAINLY SHOULD SEE THE SUN BREAKING OUT ACROSS THE WEST...BUT DO THINK WE SHOULD SEE AT LEAST SOME BREAKS FOR THE EAST AS WELL. WITH ANY SUN THE POTENTIAL IS CERTAINLY THERE FOR TEMPS TO RISE INTO THE LOWER 70S FOR A LARGE PORTION OF THE AREA. HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY TONIGHT WILL BUILD ACROSS THE FORECAST AREA BEHIND THE FRONT. UPPER LEVELS WILL BECOME ZONAL IN NATURE IN THE WAKE OF THE DEPARTING SHORTWAVE. DESPITE THE NORTHERLY FLOW THE AIRMASS IS REALLY NOT THAT COLD AND WILL RESULT IN LOW TEMPS GENERALLY NOT THAT FAR FROM CLIMATOLOGY FOR LATE NOVEMBER (IF NOT A FEW DEGREES ABOVE) WITH LOWER AND MIDDLE 40S ACROSS ARE FAR NORTHERN ZONES TO THE UPPER 40S AND LOWER 50S OVER THE SOUTH. SURFACE RIDGE MOVES EAST ON FRIDAY BUT IS REPLACES RAPIDLY BY YET ANOTHER HIGH BUILDING INTO THE SOUTHEAST. MID/UPPER LEVEL RIDGING WILL ALSO BEGIN TO BUILD NORTH OVER THE AREA FROM THE GOMEX BY LATE IN THE DAY. THIS PATTERN WILL HOLD THROUGH SATURDAY WITH THE UPPER RIDGING BECOMING EVEN STRONGER. THE RESULT WILL THE FAIR WEATHER AND GENERALLY ABOVE NORMAL TEMPS FOR THE END OF NOVEMBER AND BEGINNING OF DECEMBER. ON FRIDAY...WILL BE EXPECTING LOWER 70S FOR THE NORTHERN ZONES AND LOWER TO MIDDLE 70S ACROSS THE SOUTH. ADDED ANOTHER COUPLE OF DEGREES TO FRIDAY`S TEMPS FOR SATURDAY...HOWEVER WITH THE STRONG UPPER RIDGE AND 850MB TEMPS IN THE 12-15C RANGE...THE POTENTIAL IS THERE FOR THESE FORECAST NUMBERS TO BE A FEW DEGREES TOO COOL. THERE ARE TWO CONCERNS FOR SATURDAY WHEN IT COMES TO TEMPS...FIRST WILL BE JUST HOW MUCH MIXING WE WILL SEE WITH THE SURFACE RIDGE IN FIRM CONTROL. WITH THIS PACKAGE WILL GO WITH LESS MIXING RESULTING IN THE COOLER FORECAST TEMPS OF LOWER AND MIDDLE 70S. AS MENTIONED ABOVE IF THE DAYTIME MIXING IS UNDER-ESTIMATED THEN MIDDLE TO UPPER 70S ARE NOT OUT OF THE QUESTION. THE OTHER CONCERN IS FOR LOCATIONS ALONG THE COAST. THE THE SURFACE RIDGE SLIDES TO OUR NORTHEAST DURING SATURDAY...LOW LEVEL FLOW WILL COME AROUND TO THE EAST AND THEN SOUTHEAST FOR THE AFTERNOON. IF THIS VEERING OF THE WINDS HAPPENS FAST ENOUGH...THE FLOW WILL BE COMING OVER THE NOW COOLER SHELF WATERS WHICH ARE IN THE MIDDLE AND UPPER 60S. IF THIS WERE TO HAPPEN THEN COASTAL LOCATIONS FROM WAKULLA COUNTY WESTWARD WOULD LIKELY HIT THEIR HIGH TEMPS AROUND NOON AND THEN SETTLE BACK DOWN INTO THE UPPER 60S FOR THE AFTERNOON. && .LONG TERM (SUNDAY-THURSDAY)... THE 00 UTC GFS AND 12 UTC ECMWF REMAIN IN GOOD AGREEMENT ON THE LARGE SCALE SYNOPTIC PATTERN THROUGH WEDNESDAY...AS BOTH MODELS REPLACE THE EASTERN CONUS 500 MB RIDGE (SUNDAY) WITH A LONG WAVE TROUGH THROUGH MID WEEK NEXT WEEK. TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE AVERAGE SUNDAY WITH A 591 DM HIGH CENTERED OVER NORTH FL. THE NEXT COLD FRONT IS STILL SCHEDULED TO PASS THROUGH OUR AREA MONDAY MORNING...AND THERE IS LITTLE DIFFERENCE IN THE FRONTAL POSITIONS OF THE GFS AND ECMWF AT 12 UTC MONDAY. THEY ALSO SHOW A WEAKENING BAND OF MOISTURE ASSOCIATED WITH THE FRONT...WHICH IS TYPICAL WITH SUCH A SYSTEM. GFS MOS POPS ARE STILL ONLY IN THE 20-40 PERCENT RANGE FOR SUNDAY NIGHT AND MONDAY MORNING...WHICH WE WILL LEAVE ALONE FOR NOW SINCE THE EXACT TIMING OF THE FRONTAL PASSAGE WILL IMPACT THE RAIN FORECAST (AS TO WHETHER IT OCCURS BEFORE OR AFTER 12 UTC MONDAY). COLD AIR ADVECTION WILL OCCUR MONDAY AND MONDAY NIGHT...BUT IT STILL APPEARS THAT THE BULK OF THE COLD AIR WILL REMAIN WELL TO OUR NORTH OVER THE MID ATLANTIC AND NEW ENGLAND REGIONS. EVEN THOUGH 850 MB TEMPERATURES WILL NOT BE ALL THAT COLD...THE ENTIRE TROPOSPHERE WILL BE EXTREMELY DRY BY TUESDAY MORNING. THIS...COUPLED WITH LIGHT WINDS AS THE RIDGE NOSES INTO THE AREA BY TUESDAY MORNING...WILL RESULT IN STRONG RADIATIONAL COOLING. WE PLAN TO LEAN MORE TOWARD THE COOLER GFS BIAS CORRECTED GRIDS THAN THE WARMER GFS MOS...WHICH IS STILL HEAVILY INFLUENCED BY CLIMATOLOGY THIS FAR OUT. TEMPERATURES WILL BE SLIGHTLY BELOW AVERAGE TUESDAY AFTERNOON THROUGH THURSDAY MORNING. MODEL DIFFERENCES ARISE THURSDAY AS THE GFS QUICKLY DEVELOPS A FAIRLY POTENT SOUTHERN STREAM LOW PRESSURE SYSTEM OVER TX...WHILE THE ECMWF COMPLETELY MISSES THIS FEATURE AND JUST HAS ZONAL FLOW OVER THE CONUS. && .AVIATION... WIDESPREAD CIGS (2.5K TO 4K FT) WILL CONTINUE THROUGH THE OVERNIGHT HOURS. THE LATEST GFS MOS HAS BACKED OFF ON A WIDESPREAD DENSE FOG EVENT...WHICH MAKES SENSE GIVEN THE WARMING EFFECTS OF THE STRATOCU FIELD AND THE FACT THAT EASTERLY BOUNDARY LAYER WINDS ARE RARELY ASSOCIATED WITH DENSE FOG IN THIS AREA. MOS IS STILL GOING FOR A PERIOD OF LIFR CIGS AT MOST OF THE TERMINALS...BUT WE THINK THIS TOO IS UNLIKELY BASED ON RECENT TRENDS AND THE LATEST SREF GUIDANCE. IF ANY LIFR CIGS DEVELOP...THEY WOULD PROBABLY OCCUR AT KVLD. MVFR CIGS WILL DIMINISH FROM WEST TO EAST BY LATE MORNING AT KPFN AND KDHN...BY EARLY AFTERNOON AT KTLH AND KABY...AND BY MID TO LATE AFTERNOON AT KVLD. WINDS WILL BE N-NE AROUND 5 KT THROUGH THE DAY. && .MARINE... HIGH PRESSURE WEAKENS OVER THE FORECAST WATERS TODAY AS A WEAK COLD FRONT APPROACHES FROM THE NORTHWEST. THIS FRONT WILL CROSS THE WATERS DURING THE LATE MORNING AND AFTERNOON HOURS WITH LITTLE MORE THAN A WIND SHIFT FORM NORTHEAST TO NORTHWEST. A BRIEF PERIOD OF CAUTIONARY LEVEL WINDS ARE POSSIBLE BEHIND THE FRONT...HOWEVER WILL STAY WITH WINDS JUST BELOW THIS LEVEL AND LEAVE OUT HEADLINE MENTION. HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY WILL BUILD BACK OVER THE WATER TONIGHT. THIS HIGH WILL MOVE RAPIDLY EASTWARD AND BE REPLACED BY YET ANOTHER SURFACE RIDGE THAT WILL HOLD CONTROL OF THE FORECAST WATERS THROUGH THE UPCOMING WEEKEND. && .FIRE WEATHER... WEAK AND DRY COLD FRONT WILL CROSS THROUGH THE FORECAST AREA TODAY. THIS FRONT WILL NOT HAVE MUCH PUNCH TO IT WITH LIMITED DRY AIR AND COLD AIR ADVECTION IN ITS WAKE. IN FACT HIGH TEMPS ARE FORECAST TO BE SEVERAL DEGREES ABOVE AVERAGE FRIDAY THROUGH THE WEEKEND. EVEN WITH THE WARMER AFTERNOON TEMPS...THE LACK OF DRY LOW LEVEL AIR IS EXPECTED TO KEEP RELATIVE HUMIDITY VALUES GENERALLY ABOVE CRITICAL LEVELS INTO THE UPCOMING WEEKEND. WE MAY SEE RH VALUES APPROACH 35 PERCENT IN A FEW LOCATIONS ACROSS THE EASTERN FL PANHANDLE ON FRIDAY AFTERNOON...HOWEVER IT WILL BE VERY BRIEF AND MOST LOCATIONS WILL LIKELY BOTTOM OUT IN THE LOWER 40S. THE NEXT CHANCE FOR A FEW SHOWERS OR THUNDERSTORMS WILL BE ALONG A COLD FRONT EXPECTED TO CROSS THE FORECAST AREA ON MONDAY. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 72 49 73 48 74 / 15 0 0 0 0 PANAMA CITY 72 50 71 50 71 / 0 0 0 0 0 DOTHAN 70 45 70 44 72 / 0 0 0 0 0 ALBANY 70 45 70 44 71 / 0 0 0 0 0 VALDOSTA 72 49 73 48 73 / 20 0 0 0 0 CROSS CITY 76 52 76 51 75 / 30 05 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ AVIATION/LONG TERM...FOURNIER PUBLIC/MARINE/FIRE WX...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 100 AM EST FRI NOV 30 2007 .SYNOPSIS... HIGH PRESSURE WILL BUILD EAST ACROSS THE AREA THROUGH SATURDAY NIGHT. A COLD FRONT WILL APPROACH FROM THE WEST SUNDAY. && .NEAR TERM /THROUGH TODAY/... SURFACE HIGH PRESSURE WAS EXTENDING FROM THE OHIO VALLEY INTO THE LOWER MS RIVER VALLEY TONIGHT. A WEAK FRONTAL BOUNDARY WAS CROSSING THE UPSTATE INTO THE MIDLANDS THIS EVENING. WEAK LOW PRESSURE WAS LOCATED OFF THE SOUTHEAST COAST. ISENTROPIC LIFT ALLOWING CLOUDS TO DEVELOP ACROSS THE EXTREME EASTERN MIDLANDS TO THE COAST. MODELS INDICATING MOST OF THE CLOUDINESS SHOULD BE CONFINED TO THE EASTERN THIRD OF THE SC. ONLY EXPECT PASSING CLOUDS ACROSS THE WESTERN MIDLANDS AS THE WEAK FRONTAL BOUNDARY MOVES THROUGH. H850 FLOW BECOMING NORTHWEST FRIDAY MORNING...SO CLOUDS WILL BEGIN TO CLEAR IN THE EAST. LIGHT FOG ACROSS THE EAST SHOULD DIMINISH ONCE THE FRONTAL FRONTAL BOUNDARY MOVES THROUGH. 00Z NAM AND RUC DEVELOPING A LOW LEVEL JET LATE TONIGHT FOR MIXING OF THE BOUNDARY LAYER. DEWPOINTS RANGING FROM THE MID 30S NORTHWEST TO THE UPPER 40S SOUTHEAST. AS A RESULT COOLEST TEMPS IN THE MID/UPPER 30S WILL BE WEST WITH LOWS IN THE LOW/MID 40S EAST. HAVE ADJUST CLOUD COVER AND HOURLY TEMPERATURE/DEWPOINTS FOR THE OVERNIGHT. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... HIGH PRESSURE CENTERED OVER THE NORTHEASTERN STATES EXTENDING SOUTHWEST ACROSS THE CAROLINAS. BOUNDARY LAYER TEMPS A LITTLE COOLER FRIDAY WITH NEUTRAL TEMPERATURE ADVECTION...SO SLIGHTLY COOLER TEMPS EXPECTED. 500MB HEIGHTS RISING DURING THE DAY SATURDAY IN RESPONSE TO A LOW PRESSURE SYSTEM DEVELOPS IN THE PLAINS...SO LOW LEVEL WARM ADVECTION DEVELOPING DURING THE AFTERNOON. MODEL T-SECTIONS SUGGEST INCREASING MID TO HIGH LEVEL CLOUDS THROUGH THE PERIOD. && .LONG TERM /SUNDAY THROUGH THURSDAY/... LOW PRESSURE SYSTEM MOVING NORTHEAST TOWARD THE GREAT LAKES REGION SUNDAY. GFS APPEARS SIMILAR TO ECMWF AND ENSEMBLE MEAN WITH REGARDS TO TIMING OF FRONTAL PASSAGE EARLY MONDAY. BEST LIFT AND MOISTURE FLUX INTO THE REGION WILL BE SUNDAY NIGHT...WILL CONTINUE CHANCE THEN DECREASING THREAT MONDAY MORNING. COLD AIR ADVECTION BEHIND FRONT SHOULD RESULT IN TEMPERATURES BELOW NORMAL THROUGH MID TO LATE WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD...EXCEPT FOR POSSIBLE IFR VISIBILITIES IN FOG AT OGB/AGS. LOW CLOUDS ALONG THE COAST HAVE EXPANDED WESTWARD AND INTO OGB...WHICH SHOULD WARM TEMPERATURES A DEGREE OR TWO. WITH THE SLIGHT WARMING WILL EXPECT THE FOG VSBYS TO INCREASE FROM IFR TO MVFR OVER THE NEXT HOUR OR TWO. THE OTHER CONCERN OVERNIGHT IS AGS...WHERE FOR HAS ALSO DEVELOPED. WITH LOW CLOUDS NOT ADVANCING AS FAR AS AGS OVERNIGHT BELIEVE THE FOG WILL REDUCE VSBYS TO IFR FROM 06Z THROUGH 10Z. REMAINING FOG AT AGS/OGB WILL BURN OFF BY 14Z WITH REMAINDER OF TAF PERIOD VFR. WINDS THROUGH THE PERIOD WILL BE LESS THAN 10 KNOTS FROM THE NORTHEAST. MVFR CONDITIONS POSSIBLE SUNDAY NIGHT AND MONDAY...OTHERWISE...NO SIGNIFICANT IMPACTS TO AVIATION THROUGH TUESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 428 PM EST FRI NOV 30 2007 .SHORT TERM... TONIGHT THROUGH SATURDAY AFTERNOON FAST MOVING LOW PRESSURE IS IN THE PROCESS OF EXITING THE REGION. COLD FRONT ASSOCIATED WITH THIS SYSTEM HAS CLEARED THE FA AND VIGOROUS COLD AIR ADVECTION ALONG WITH STAGGERING NEGATIVE THETA-E ADVECTION IS ONGOING PER ADVANCING SFC HIGH PRESSURE. LAKE EFFECT CLOUDS ARE TRYING TO HANG ON OVER THE NORTHERN ZONES. HOWEVER...EXTREMELY DRY AIR FROM THE ADVECTING CP AIRMASS IS LIMITING THIS PROCESS. TEMPERATURES ARE IN THE PROCESS OF FALLING INTO THE 20S NORTHWEST WITH LOWER 40S STILL PRESENT OVER THE SE. FARTHER UPSTREAM....DIGGING UPPER TROUGH OVER THE EASTERN PACIFIC IS BEGINNING TO MAKE LANDFALL OVER NORTHERN CA. PHASING BETWEEN THIS SYSTEM AND THE WEST BAJA UPPER TROUGH WILL PRODUCE VAST LARGE SCALE ASCENT AS THESE SYSTEMS EJECT OUT INTO THE PLAINS BY TOMORROW...SUPPORTING THE DEVELOPMENT OF DEEP LOW PRESSURE OVER THE CENTRAL US. TONIGHT...STRONG SFC HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION OVERNIGHT. WINDS WILL DROP OFF AFTER MIDNIGHT. WITH EXTREMELY DRY AIR IN PLACE/LIGHT WINDS/AND MOSTLY CLEAR SKIES SAVE INCREASING CIRRUS SHIELD PER HEIGHT RISES...EXPECTING A COLD NIGHT TONIGHT WITH LOWS IN THE TEENS ANTICIPATED. WOULD NOT BE SURPRISED IF A FEW ARES IN THE NORTHEAST DROP INTO THE SINGLE DIGITS. TRAJECTORY ANALYSIS INDICATES ADVECTING AIR MASS HAS ALREADY PRODUCED LOWS BELOW ZERO UPSTREAM OVER THE DAKOTAS EVEN WHERE SNOW WAS ABSENT. SATURDAY...MID AND HIGH CLOUDS WILL BE ON THE INCREASE AS LOW PRESSURE DEEPENS OVER THE PLAINS...FORCING THETA-E ADVECTION. VERY DRY AIR WILL BE IN PLACE IN THE LOWER LEVELS. FORECAST MODELS INDICATE A DEWPOINT OF -40C AT H85 12Z SATURDAY. STRONG SUBSIDENCE PER ADVANCING HIGH PRESSURE WILL ACT TO FURTHER DRY THIS LAYER INTO THE EARLY AFTERNOON. GFS/ECWMF/AND GEM ALL INDICATE LIGHT PRECIP MOVING INTO REGION PER ISENTROPIC UPGLIDE/THETA-E ADVECTION. NAM/WRF CONFINES ALL PRECIP WEST OF THE FA. IN EXAMINING NMM AND RUC 13 SIM REFLECTIVITY...IT IS OBVIOUS THAT PRECIP INTENSITY IS WEAK AND HIGHEST RETURNS ARE NW OF THE FA. GIVEN STAGGERING AMOUNT OF DRY AIR IN PLACE AND ESE LOW LEVEL FLOW REINFORCING DRY SUBCLOUD AIR...HAVE CONTINUED TO FAVOR THE NAM/WRF SOLUTION AS IT IS THE SLOWEST TO ERODE THE DRY SUB CLOUD LAYER IN PLACE. THIS MAKES THE MOST SENSE GIVEN MAIN UPPER IMPULSE AND ASSOCIATE LARGE SCALE ASCENT WILL BE WELL WEST OF THE REGION OVER THE PLAIN STATES UNTIL THE EVENING. HENCE...FORCING AND ANY SYMMETRIC INSTABILITY WILL BE WEAK THROUGH THE PERIOD. HAVE DROPPED POPS TO LIKELY NW...WITH CHANCE EVERY ELSE. BEST PRECIP CHANCES STILL RESIDE IN THE NORTHWEST LATE IN THE AFTERNOON. GIVEN EXPECTED WEAK FORCING...THINKING ANY PRECIP WILL BE ON THE LIGHT SIDE WITH THIS FIRST WAVE OF ASCENT. RETAINED SNOW SLEET MENTION NORTH...WITH RAIN/ZR/SLEET IN THE SOUTH PER TOP DOWN ANALYSIS. WITH ANTICIPATED LOW IMPACT AFTERNOON PRECIP...HAVE MOVED WATCH TO 00Z PER COORDINATION WITH SURROUNDING WFOS. && .LONG TERM... SHRTWV DIGGING SOUTH ALONG WEST COAST THIS AFTN. IN RESPONSE, CUT-OFF UPPER LOW OFF BAJA WAS OPENING UP AND LIFTING NE. SUB-TROPICAL MOISTURE SEEN ON WATER VAPOR LOOPS STREAMING NORTHWARD ACROSS MEXICO INTO SWRN U.S. IN ADVANCE OF THIS SYSTEM. GULF MOISTURE SHOULD ALSO BE TAPPED AS SFC SYSTEM MOVES INTO PLAINS ON SAT. MODELS IN DECENT AGREEMENT THAT SFC LOW WILL TRACK NE FROM KS/NEB SAT EVE TO NRN LWR MI SUN EVE. STRONG WARM FRONT SE OF TRACK OF SFC LOW EXPECTED TO MOVE THROUGH THE CWA SAT NGT AND SUN MORNING. WARM/MOIST AIR BEING LIFTED OVER THE FRONT SHOULD RESULT IN WIDESPREAD PCPN SAT NGT. AS FOR PRECIP TYPE... APPEARS WILL BE COLD ENOUGH ALOFT AND DRY ENOUGH IN LOW LEVELS FOR ONSET TO BE MAINLY SNOW/SLEET ACROSS THE ENTIRE CWA. STRONG WAA BETWEEN 5K-10K FT SHOULD QUICKLY CHANGE THE SNOW/SLEET MIX TO A FREEZING RAIN/SLEET MIX. GENERALLY FOLLOWED NAM QPF FIELDS WHICH SUGGESTS POTENTIAL FOR A QUARTER TO HALF INCH OF PRECIP SAT NGT. ALSO SLOPED FGEN FORCING FCST CONSISTENTLY BY MODELS COULD LEAD TO SOME HEAVIER BANDS AS STRONG WAA ALOFT MOVES INTO THE AREA. POTENTIAL FOR QUARTER INCH OF GLAZE STILL APPEARS SUFFICIENT TO LEAVE WATCH UP FOR SAT NGT ACROSS NRN CWA AND EARLY SUNDAY NE. AS LOW PASSES TO OUR NORTH ON SUNDAY WAA WILL RAISE TEMPS IN THIS AREA WELL ABOVE FREEZING ON SUNDAY. LEANED TOWARD COOLER MAV NORTH WHERE MELTING ICE SHOULD HOLD TEMPS DOWN...WHILE GENERALLY SPLIT MAV/MET DIFFERENCE ACROSS SOUTH. COLD FRONT ASSOCIATED WITH THE SFC LOW IS EXPECTED TO SWEEP EAST ACROSS THE AREA SUNDAY EVE. LAST COUPLE RUNS OF THE NAM HAVE BEEN INDICATING WK INSTABILITY DEVELOPING OVER SRN PORTIONS OF CWA AHEAD OF THE COLD FRONT. FOR NOW CONTD WITH SHOWERS BUT MAY NEED TO CONSIDER ADDING TSTMS TO THIS AREA IF MODELS PERSIST WITH THIS SOLUTION. WRAP AROUND AND LAKE EFFECT SNOW SHOWERS SHOULD LINGER INTO MON NGT. CLIPPER SYSTEM EXPECTED TO MOVE THROUGH TUE AFTN/NIGHT WITH SOME LINGERING LAKE EFFECT IN THE WAKE OF THIS SYSTEM WED NGT. RIDGING EXPECTED TO END THIS ACTIVITY THU, BUT ANOTHER SHRTWV AND WAA ON BACKSIDE OF THE RIDGE MAY SPREAD SOME RN/SN INTO THE AREA ON FRI. && .AVIATION (18Z TAFS)... DEPARTING LOW PRESSURE WILL CONTINUE TO SUPPORT STRONG GUSTY WINDS ACROSS THE FA. LOOK FOR A FEW MVFR CIGS OVER NORTHERN PORTIONS OF THE FORECAST AREA DUE TO LAKE PROCESSES. CLOUDS AND WINDS WILL DIMINISH THIS EVENING AS HIGH PRESSURE BUILDS INTO THE AREA. LOOK FOR WINDS TO GRADUALLY VEER EASTERLY LATE TONIGHT INTO TOMORROW MORNING IN RESPONSE TO DEVELOPING LOW PRESSURE IN THE PLAIN STATES. VFR CONDITIONS CAN BE EXPECTED FROM THIS EVENING THROUGH TOMORROW MORNING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR INZ006-007. WINTER STORM WATCH FROM SATURDAY EVENING THROUGH LATE SATURDAY NIGHT FOR INZ003>005-008-009. MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR MIZ079>081. WINTER STORM WATCH FROM SATURDAY EVENING THROUGH LATE SATURDAY NIGHT FOR MIZ077-078. OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR OHZ001-002. LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SATURDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...TAYLOR AVIATION...CHAMBERLAIN in AREA FORECAST DISCUSSION...UPDATED FOR 00Z AVIATION FORECAST NATIONAL WEATHER SERVICE DES MOINES IA 545 PM CST FRI NOV 30 2007 UPDATED FOR 00Z AVIATION... .SHORT TERM...TONIGHT THROUGH SUNDAY 19Z SFC ANLYS INDICATED 1035 MB HIGH OVER NW IOWA WITH BROADER EXTENT OF SURFACE HIGH INTO KANSAS AND MO. COLD AIR AT 850 HAS PUSHED SOUTH OF IOWA INTO MO AND KS AS WELL...WITH MUCH COLDER AIR IN THE BOUNDARY LAYER. AS HIGH RETREATS EAST OF THE AREA OVERNIGHT...A SLIGHT GRADIENT WILL DEVELOP OVER WESTERN IOWA WITH WEAK WARM AIR ADVECTION BEGINNING AFTER 06Z. WITH THIS IN MIND HAVE PLACED LOW TEMPS RIGHT AROUND MIDNIGHT WITH NEAR STEADY TEMPS OVER THE FAR NORTH WHERE A LIGHT SNOWFIELD NOW EXITS ALONG THE HIGHWAY 9 CORRIDOR. AS TEMPS WARM IN THE WEST TOWARD MORNING...SO WILL AN INCREASE IN CLOUDS FROM ADVANCING SYSTEM AND A SWITCH TO A SOUTHERLY WIND COMPONENT. WEAK THETA-E ADVECTION HAS ALREADY BEGUN TO THE NW OF THE AREA...HOWEVER QUITE RELATIVE AND STILL THINK SOME RADIATIONAL COOLING WILL WIN OUT IN THE EVENING HOURS ACROSS THE NORTH. HAVE BASICALLY USED AND ADJUSTED RUC FORECAST FOR TONIGHT. WAA ADVECTION IN THE MID AND LOWER LAYERS WILL BE RAPIDLY INTENSIFYING BY THE END OF TONIGHT SO HAVE 20 PERCENT CHCS OF PCPN THROUGH ABOUT A DNS-LWD LINE THROUGH 9 AM WITH 50 POPS ACROSS THE EXTREME SOUTHWEST COUNTIES BY 12Z (6AM) SATURDAY. INITIAL PCPN BURST WILL BE SNOW AND SLEET. SITUATION LOOKS TO DETERIORATE QUICKLY SAT MORNING. MODELS IN GOOD AGREEMENT WITH FORCING AND QPF...BUT LOW LEVEL TEMPERATURE DETAILS ARE MOST PROBLEMATIC AND UNFORTUNATELY THE KEY TO THE FORECAST. ALTHOUGH 18Z RUN HAS WARMED SOMEWHAT...12Z NAM WAS ON COOL END OF THERMAL ENVELOPE AND SEEMS TO BE AN OUTLIER. CONSIDERING THE STRENGTH OF WARM ADVECTION AND POTENTIAL LATENT HEAT RELEASE WITH FREEZING RAIN...FEEL THE NAM IS TOO COOL AND NOT AGGRESSIVE ENOUGH WITH PRESSURE FALLS INTO MO VALLEY. ALTHOUGH IT IS NOT DEPICTED IN THE FORECAST TO KEEP THINGS SIMPLER...WOULD NOT BE SURPRISED TO SEE CONVECTION EITHER WHOSE LATENT HEAT WOULD CAUSE SIMILAR WARMER RESULTS. WITH THIS IN MIND...THE FORECAST GENERALLY FOLLOWED 09Z SREF SFC TEMPS/DEWPOINTS AND GFS FORCING WHICH SEEMED TO BE A NICE COMPROMISE BETWEEN THE COOL NAM AND CONTINUALLY WARM END ECMWF. MODELS TYPICALLY UNDERESTIMATE STRONG COOLING WHICH WE HAVE IN PLACE NOW...AND ALSO STRONG WAA SO WARMER END OF FORECAST SOLUTIONS WILL HAVE TO BE WATCHED DURING TRANSITION. IN MORE DETAIL...FORCING REALLY INCREASES SAT MORNING AS SWRN TROUGH EJECTS INTO THE CENTRAL PLAINS. EARLY ON UVM IS MAINLY DRIVEN BY THERMODYNAMICS WITH ABOUT 12 HOURS OF THETA-E ADVECTION AND FRONTOGENETICAL FORCING ON BACK EDGE. THIS SHOWS UP QUITE WELL IN 290-300K ISENT LAYER WITH PROLONGED AND IMPRESSIVE MOISTURE TRANSPORT AND UVM. KINEMATIC FORCING ALSO INCREASES AROUND 00Z WHEN PARENT SHRT WV LIFTS THROUGH. THIS COULD VERY WELL TURN INTO AN EXTREME ICE STORM EVENT IN THE NRN HALF OF THE STATE WITH QPF AMOUNTS HOVERING AROUND AN INCH...AND THIS MAKES SENSE WITH PWS PUSHING RECORD VALUES. THE PCPN WILL SWITCH TO RAIN SOUTH AND HOPEFULLY ALLEVIATE A PROLONGED EVENT THERE. HAVE SWITCHED WATCH TO WINTER STORM WARNING NORTH WHERE SNOW WILL FALL INITIALLY...CAPPED WITH SIGNIFICANT SLEET AND FREEZING RAIN ACCUMS. WITH SURGE OF WARM LAYER AND RELATIVELY LOW SNOW RATIOS...SNOW POTENTIAL WILL NOT LAST TOO LONG BUT MAY DROP 1-5 INCH SNOWS WITH MAX ALONG MN BORDER. CENTRAL AND SOUTH CLIPPED LENGTH OF HEADLINE SWITCHING TO ICE STORM WARNING WHERE PCPN SHOULD MAINLY BE LIQUID BEFORE TEMPS APPROACH OR EXCEED FREEZING. ALTHOUGH APPRECIABLE PCPN MAY NOT FALL IN NRN PORTIONS AFTER 03Z...EVEN LIGHT RAIN OR FREEZING DRIZZLE MAY CONTINUE TO CAUSE PROBLEMS AND ACCUMULATE SO HAVE KEEP WARNING TIL 12Z. AFTER THE STORM DEPARTS...WENT AT OR BELOW THE COOLEST END OF GUIDANCE. MODELS HAVE NOT BEEN ACCURATELY DEPICTING THE AMOUNT OF COLD AIR BEHIND THESE SYSTEMS AND THAT DOES NOT EVEN TAKE INTO ACCOUNT THE SNOW AND ICE THAT WILL LIKELY BE ON THE GROUND. .LONG TERM...SUN NIGHT THROUGH FRIDAY A CLIPPER SYSTEM WILL DROP SOUTHEAST ACROSS THE REGION TUESDAY AND TUESDAY NIGHT AND MAY BRUSH NORTHEAST SECTIONS WITH SOME LIGHT SNOW. SOME FLURRIES SHOULD LINGER INTO WEDNESDAY NORTHEAST WITH COLD AIR AND CYCLONIC FLOW. THE GFS IS MORE AGGRESSIVE WITH THE ECMWF WITH THE PUSH OF COLD AIR BEHIND THE SYSTEM TUESDAY NIGHT INTO WEDNESDAY. WILL STAY CLOSE TO HPC GUIDANCE FOR TEMPS FOR NOW. THE GFS BRINGS ANOTHER S/W TROUGH ACROSS IOWA LATE THURSDAY WHILE THE ECMWF DIGS THE SYSTEM FARTHER SOUTH. CONFIDENCE NOT HIGH ENOUGH TO INTRODUCE ANY ADDITIONAL POPS AT THIS TIME. && .AVIATION...1/00Z VFR EARLY IN FORECAST PERIOD WITH SURFACE HIGH PRESSURE OVER IOWA AT 00Z. SURFACE HIGH WILL MOVE OFF TO THE SOUTHEAST AND EXPECT RAPID WAA AND MOISTURE ADVECTION ACROSS IA AFTER 09Z AND CONTINUE THROUGH THE PERIOD. SNOW...IP AND FREEZING RAIN IN FORECAST AFTER 14Z. SURFACE TEMPS MAY WARM ENOUGH TO CHANGE PCPN OVER THE RA BY 18Z IN THE SOUTH. AS AMS SATURATES...EXPECT CIGS TO DECREASE THROUGH THE DAY. && .DMX WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING ALONG AND NORTH OF HIGHWAY 30 PLUS TAMA COUNTY 12Z SAT-12Z SUN. ICE STORM WARNING 12Z-21Z SAT REMAINDER OF FORECAST AREA. && $$ MDR/BSS/RPK/JJ ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 353 PM CST FRI NOV 30 2007 .SHORT TERM...TONIGHT THROUGH SUNDAY 19Z SFC ANLYS INDICATED 1035 MB HIGH OVER NW IOWA WITH BROADER EXTENT OF SURFACE HIGH INTO KANSAS AND MO. COLD AIR AT 850 HAS PUSHED SOUTH OF IOWA INTO MO AND KS AS WELL...WITH MUCH COLDER AIR IN THE BOUNDARY LAYER. AS HIGH RETREATS EAST OF THE AREA OVERNIGHT...A SLIGHT GRADIENT WILL DEVELOP OVER WESTERN IOWA WITH WEAK WARM AIR ADVECTION BEGINNING AFTER 06Z. WITH THIS IN MIND HAVE PLACED LOW TEMPS RIGHT AROUND MIDNIGHT WITH NEAR STEADY TEMPS OVER THE FAR NORTH WHERE A LIGHT SNOWFIELD NOW EXITS ALONG THE HIGHWAY 9 CORRIDOR. AS TEMPS WARM IN THE WEST TOWARD MORNING...SO WILL AN INCREASE IN CLOUDS FROM ADVANCING SYSTEM AND A SWITCH TO A SOUTHERLY WIND COMPONENT. WEAK THETA-E ADVECTION HAS ALREADY BEGUN TO THE NW OF THE AREA...HOWEVER QUITE RELATIVE AND STILL THINK SOME RADIATIONAL COOLING WILL WIN OUT IN THE EVENING HOURS ACROSS THE NORTH. HAVE BASICALLY USED AND ADJUSTED RUC FORECAST FOR TONIGHT. WAA ADVECTION IN THE MID AND LOWER LAYERS WILL BE RAPIDLY INTENSIFYING BY THE END OF TONIGHT SO HAVE 20 PERCENT CHCS OF PCPN THROUGH ABOUT A DNS-LWD LINE THROUGH 9 AM WITH 50 POPS ACROSS THE EXTREME SOUTHWEST COUNTIES BY 12Z (6AM) SATURDAY. INITIAL PCPN BURST WILL BE SNOW AND SLEET. SITUATION LOOKS TO DETERIORATE QUICKLY SAT MORNING. MODELS IN GOOD AGREEMENT WITH FORCING AND QPF...BUT LOW LEVEL TEMPERATURE DETAILS ARE MOST PROBLEMATIC AND UNFORTUNATELY THE KEY TO THE FORECAST. ALTHOUGH 18Z RUN HAS WARMED SOMEWHAT...12Z NAM WAS ON COOL END OF THERMAL ENVELOPE AND SEEMS TO BE AN OUTLIER. CONSIDERING THE STRENGTH OF WARM ADVECTION AND POTENTIAL LATENT HEAT RELEASE WITH FREEZING RAIN...FEEL THE NAM IS TOO COOL AND NOT AGGRESSIVE ENOUGH WITH PRESSURE FALLS INTO MO VALLEY. ALTHOUGH IT IS NOT DEPICTED IN THE FORECAST TO KEEP THINGS SIMPLER...WOULD NOT BE SURPRISED TO SEE CONVECTION EITHER WHOSE LATENT HEAT WOULD CAUSE SIMILAR WARMER RESULTS. WITH THIS IN MIND...THE FORECAST GENERALLY FOLLOWED 09Z SREF SFC TEMPS/DEWPOINTS AND GFS FORCING WHICH SEEMED TO BE A NICE COMPROMISE BETWEEN THE COOL NAM AND CONTINUALLY WARM END ECMWF. MODELS TYPICALLY UNDERESTIMATE STRONG COOLING WHICH WE HAVE IN PLACE NOW...AND ALSO STRONG WAA SO WARMER END OF FORECAST SOLUTIONS WILL HAVE TO BE WATCHED DURING TRANSITION. IN MORE DETAIL...FORCING REALLY INCREASES SAT MORNING AS SWRN TROUGH EJECTS INTO THE CENTRAL PLAINS. EARLY ON UVM IS MAINLY DRIVEN BY THERMODYNAMICS WITH ABOUT 12 HOURS OF THETA-E ADVECTION AND FRONTOGENETICAL FORCING ON BACK EDGE. THIS SHOWS UP QUITE WELL IN 290-300K ISENT LAYER WITH PROLONGED AND IMPRESSIVE MOISTURE TRANSPORT AND UVM. KINEMATIC FORCING ALSO INCREASES AROUND 00Z WHEN PARENT SHRT WV LIFTS THROUGH. THIS COULD VERY WELL TURN INTO AN EXTREME ICE STORM EVENT IN THE NRN HALF OF THE STATE WITH QPF AMOUNTS HOVERING AROUND AN INCH...AND THIS MAKES SENSE WITH PWS PUSHING RECORD VALUES. THE PCPN WILL SWITCH TO RAIN SOUTH AND HOPEFULLY ALLEVIATE A PROLONGED EVENT THERE. HAVE SWITCHED WATCH TO WINTER STORM WARNING NORTH WHERE SNOW WILL FALL INITIALLY...CAPPED WITH SIGNIFICANT SLEET AND FREEZING RAIN ACCUMS. WITH SURGE OF WARM LAYER AND RELATIVELY LOW SNOW RATIOS...SNOW POTENTIAL WILL NOT LAST TOO LONG BUT MAY DROP 1-5 INCH SNOWS WITH MAX ALONG MN BORDER. CENTRAL AND SOUTH CLIPPED LENGTH OF HEADLINE SWITCHING TO ICE STORM WARNING WHERE PCPN SHOULD MAINLY BE LIQUID BEFORE TEMPS APPROACH OR EXCEED FREEZING. ALTHOUGH APPRECIABLE PCPN MAY NOT FALL IN NRN PORTIONS AFTER 03Z...EVEN LIGHT RAIN OR FREEZING DRIZZLE MAY CONTINUE TO CAUSE PROBLEMS AND ACCUMULATE SO HAVE KEEP WARNING TIL 12Z. AFTER THE STORM DEPARTS...WENT AT OR BELOW THE COOLEST END OF GUIDANCE. MODELS HAVE NOT BEEN ACCURATELY DEPICTING THE AMOUNT OF COLD AIR BEHIND THESE SYSTEMS AND THAT DOES NOT EVEN TAKE INTO ACCOUNT THE SNOW AND ICE THAT WILL LIKELY BE ON THE GROUND. .LONG TERM...SUN NIGHT THROUGH FRIDAY A CLIPPER SYSTEM WILL DROP SOUTHEAST ACROSS THE REGION TUESDAY AND TUESDAY NIGHT AND MAY BRUSH NORTHEAST SECTIONS WITH SOME LIGHT SNOW. SOME FLURRIES SHOULD LINGER INTO WEDNESDAY NORTHEAST WITH COLD AIR AND CYCLONIC FLOW. THE GFS IS MORE AGGRESSIVE WITH THE ECMWF WITH THE PUSH OF COLD AIR BEHIND THE SYSTEM TUESDAY NIGHT INTO WEDNESDAY. WILL STAY CLOSE TO HPC GUIDANCE FOR TEMPS FOR NOW. THE GFS BRINGS ANOTHER S/W TROUGH ACROSS IOWA LATE THURSDAY WHILE THE ECMWF DIGS THE SYSTEM FARTHER SOUTH. CONFIDENCE NOT HIGH ENOUGH TO INTRODUCE ANY ADDITIONAL POPS AT THIS TIME. && .AVIATION...30/18Z LITTLE CHANGE IN EARLY PERIODS OF TERMINAL FORECASTS WITH IFR CONDITIONS EXPECTED THROUGH AT LEAST 09Z. HOWEVER...WITH WINTER STORM BECOMING INCREASING LIKELY HAVE MVFR CEILINGS AND IFR VSBYS AT MOST SITES BY THE 15-18Z SATURDAY TIMEFRAME AS SURGE OF MOISTURE WILL BE QUITE INTENSE SATURDAY AM. DIAGNOSTICS POINT TOWARD GOOD CONFIDENCE IN FREEZING RAIN AS WELL AT LEAST FOR A PERIOD...AFTER A ROUND OF SNOW/SLEET. && .DMX WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING ALONG AND NORTH OF HIGHWAY 30 PLUS TAMA COUNTY 12Z SAT-12Z SUN. ICE STORM WARNING 12Z-21Z SAT REMAINDER OF FORECAST AREA. && $$ MDR/BSS/RPK ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 855 PM CST FRI NOV 30 2007 .DISCUSSION... CONCERN WITH POTENTIAL ICE STORM CONTINUES TO BE SFC TEMPS. EXCEPT FOR FAR SOUTHERN PORTIONS OF THE FORECAST AREA...TEMPS HAVE FALLEN BELOW FREEZING WITH DRY AIR /DEWPOINTS IN THE SINGLE DIGITS/ CONTINUING TO ADVECT IN FROM THE EAST. WITH AN AC DECK MOVING IN NOW...DO NOT ANTICIPATE TEMPS WILL DROP OFF AS THEY HAVE PREVIOUS NIGHTS...AND SHOULD STAY RELATIVELY STEADY OR FALL ONLY A COUPLE DEGREES THROUGH THE REST OF THE NIGHT. WITH THE DRY AIR ADVECTION...HAVE PUSHED BACK THE ONSET OF PRECIP ACROSS THE FORECAST AREA UNTIL AFTER MIDNIGHT. THINK THE PRECIP WILL ACTUALLY BEGIN FALLING AROUND 09Z AS MOISTURE ADVECTION AND LIFT GET STRONG ENOUGH TO OVERCOME THE DRY AIR AT THE SFC. 00Z SOUNDINGS FROM THE NAM AND RUC SHOW THE MOST LIKELY AREA FOR SIGNIFICANT ICE ACCUMULATIONS TO BE ACROSS THE NORTH WERE SFC TEMPS WILL BE BELOW FREEZING LONGER. STRONG MOISTURE ADVECTION FROM THE SOUTH AROUND 12Z WILL FORCE TEMPS TO SLOWLY CLIMB THROUGH THE MID MORNING HOURS. WITH LESS TIME FOR FZRA ALONG AND SOUTH OF I-70...ANTICIPATE ACCUMULATIONS TO BE BELOW A QUARTER OF AN INCH WITH TEMPS WARMING ABOVE FREEZING ALONG THE I-70 CORRIDOR BETWEEN 13 AND 15Z. WITH THIS IN MIND...CURRENT HAZARDS SEEM TO BE IN PRETTY GOOD SHAPE AND WILL NOT MAKE ANY ADJUSTMENTS TO THE ADVISORY OR WARNING. THE ONE THING TO LOOK OUT FOR WOULD BE IF PRECIP STARTED MUCH BEFORE 09Z. THEN THE WINDOW FOR FZRA WOULD BE A LITTLE LARGER AND ACCUMULATIONS COULD BE HIGHER FURTHER SOUTH. && WOLTERS .PREV DISCUSSION /336 PM CST/... MAIN CONCERN FOR THIS FORECAST CENTERS ON THE IMPENDING STORM SYSTEM TONIGHT THROUGH SATURDAY. WATER VAPOR SATELLITE SHOWS UPPER LOW OFF THE CA COAST BEING ABSORBED BY THE DIGGING TROUGH IN THE EASTERN PACIFIC. SUB TROPICAL MOISTURE WAS STREAMING NORTHEAST AHEAD OF THIS SYSTEM ACROSS THE FOUR CORNERS AND SOUTHWEST TEXAS. A COLD FRONT MOVED THROUGH THIS MORNING AND WAS LOCATED OVER OKLAHOMA THIS AFTERNOON. TEMPERATURES WERE RUNNING COOLER THAN GUIDANCE THIS AFTERNOON AROUND 4 DEGREES OR SO. DEW POINTS IN THE SINGLE DIGITS WERE ACROSS MUCH OF KANSAS...MISSOURI AND NEBRASKA. MAIN CONCERN FOR THIS EVENING WITH PATCHES OF CIRRUS THROUGH MID EVENING COULD SEE TEMPERATURES DROP INTO THE MIDDLE 20S NORTH OF INTERSTATE 70 AND BELOW FREEZING SOUTHEAST OF INTERSTATE 35. MODELS HAVE BEEN RUNNING TOO WARM AND ARE VIGOROUS IN SCOURING OUT THE LOW LEVEL COLD AIR. 18Z NAM HAS COME IN A BIT COOLER THAN THE 12Z RUN...THE GFS CONTINUES TO BE TOO WARM IN THE LOW LEVELS. GOOD ISENTROPIC LIFT/WARM AIR ADVECTION PATTERN SETS UP THIS EVENING AS THE LOW LEVEL JET INCREASES TO NEAR 50 KTS BY 06Z AND CONTINUES THROUGH THE NIGHT WITH 50 TO 60 KTS AT 850 MB. WITH THE SUBTROPICAL MOISTURE PLUME TO THE SOUTH CONDENSATION PRESSURE DEFICITS SHRINK RELATIVELY QUICKLY THIS EVENING REACHING SATURATION NEAR OR SHORTLY AFTER MIDNIGHT. SURFACE WINDS WILL INCREASE TO AROUND 20 KTS WITH HIGHER GUSTS CREATING A HAZARDOUS SITUATION. THIS PATTERN WILL CONTINUE THROUGH THE MID TO LATE MORNING HOURS ESPECIALLY NEAR THE NEBRASKA BORDER SO HAVE EXTENDED THE ICE STORM WARNING TO END AT NOON. TEMPERATURES WILL BE SLOW TO RECOVER NEAR THE BORDER. INCREASED THE AMOUNT OF ICING NEAR THE BORDER TO BE BETWEEN A QUARTER AND A HALF INCH. FURTHER SOUTH IN THE ADVISORY AREA LOOKING AT AMOUNTS AROUND TWO TENTHS OF AN INCH OR LESS. THE RETURN OF WARM AIR AT THE SURFACE BEHIND THE WARM FRONT WILL BE KEY TO THE ICE AMOUNTS SOUTH OF HIGHWAY 56. CURRENTLY THINKING AMOUNTS THERE WILL BE AROUND A TENTH OF AN INCH OR SO. TEMPERATURES STILL LOOK LIKE THEY WILL RISE BEHIND THE WARM FRONT TO WELL ABOVE FREEZING AND MELT THE ICE ALONG WITH A GOOD SOAKING RAIN. INCREASED QPF SATURDAY MORNING ALONG THE LINES OF HPC WITH SOME TWEAKS. THE MOISTURE EXITS THE AREA DURING THE AFTERNOON HOURS WITH THE BEST LIFT ACROSS THE FAR NORTHEAST COUNTIES INTO CENTRAL IOWA. SOME LIGHT RAIN IS STILL POSSIBLE SATURDAY NIGHT INTO EARLY SUNDAY AHEAD OF AN APPROACHING MID LEVEL TROUGH AND SURFACE COLD FRONT. THE UPPER TROUGH MOVES EAST OF THE CWA AROUND MID DAY SUNDAY ENDING PRECIPITATION. LOW LEVEL THICKNESS WOULD SUGGEST THAT SOME SNOW MAY MIX WITH THE RAIN LATE SATURDAY NIGHT AND SUNDAY MORNING BEFORE ENDING. HIGHS ON SUNDAY WILL BE ONLY IN THE 30S TO LOWER 40S. NORTHWEST FLOW SHOULD RULE MUCH OF NEXT WEEK WHICH MAKES TEMPERATURE FORECASTS TRICKY. APPEARS WARM AIR ADVECTION WILL BRING TEMPS UP ABOVE NORMAL FOR TUESDAY AND LIKELY WEDNESDAY WITH COOLER AIR ENTERING PERHAPS LATE WEDNESDAY FOR A COOLER END OF THE FORECAST. HAVE INCREASED TEMPS EARLY AND DECREASED THEM LATE WITH THIS IN MIND...BUT CAN ENVISION ACTUAL TEMPS MORE EXTREME THAN CURRENTLY FORECAST. PRECIPITATION CHANCES APPEAR RATHER LOW IN THIS REGIME WITH SOME LIGHT ACCUMULATIONS POSSIBLE WITH A SHORTWAVE AROUND WEDNESDAY NIGHT BUT WILL KEEP THINGS DRY FOR THE TIME BEING. THERE ARE INDICATIONS OF A CHANGE IN THE UPPER FLOW PATTERN AROUND FRIDAY WHICH MAY BRING MORE SIGNIFICANT PRECIPITATION CHANCES THEN...BUT AGAIN CONFIDENCE IS TOO LOW TO JUMP ON ANYTHING. && .AVIATION... CONDITIONS TO RAPIDLY WORSEN OVERNIGHT. APPEARS PRECIP WILL BEGIN IN THE 6Z-9Z TIME FRAME WITH CEILINGS DROPPING TO AT LEAST IFR DURING PEAK INTENSITY TIME...LIKELY FROM 9Z TO 15Z. TEMPS EXPECTED TO BE BELOW FREEZING NEAR THE GROUND BUT NOT FAR ABOVE SO FZRA IS EXPECTED. SOME IMPROVEMENT IS LIKELY BY LATE IN THE 18Z CYCLE. && .TOP WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING IN EFFECT FROM 06Z SATURDAY THROUGH 18Z SATURDAY PORTIONS OF NORTH CENTRAL AND NORTHEAST KANSAS...KSZ008>012-020>024. FREEZING RAIN ADVISORY IN EFFECT FROM ALONG THE INTERSTATE 70 CORRIDOR TO NEAR INTERSTATE 35 FROM 06Z SATURDAY THROUGH 15Z SATURDAY...KSZ034>040-054>056. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 317 AM CST FRI NOV 30 2007 .DISCUSSION... DAYS 1-2... WATER VAPOR LOOP SHOWS IMPRESSIVE SUB TROPICAL CYCLONE WEST OF BAJA CALIFORNIA EARLY THIS MORNING. A SIGNIFICANT PLUME OF PACIFIC MOISTURE WAS STREAMING FROM QUITE LOW LATITUDES NORTHWARD THROUGH BAJA INTO ARIZONA AND SOUTHER NEW MEXICO. THIS WILL BE THE LOW THAT GETS KICKED OUT INTO THE DESERT SOUTHWEST REGION LATER ON TODAY AND TONIGHT...WITH A SIGNIFICANT POLEWARD ADVANCEMENT OF DEEP TROPOSPHERIC MOISTURE AND LIFT. OF COURSE...PRETTY MUCH ALL OF THE PACIFIC MOISTURE WILL BE "RUNG OUT" OVER THE SOUTHERN AND CENTRAL ROCKIES...AND WILL HAVE TO RELY ON LOW LEVEL MOISTURE FROM THE GULF OF MEXICO FOR PRECIPITATION FORMATION OVER THE WESTERN AND CENTRAL GREAT PLAINS. LOW LEVEL WINDS WILL BEGIN TO INCREASE SUBSTANTIALLY...WITH SUBSEQUENT INCREASE IN VERTICAL MOTION FOR FAIRLY WIDESPREAD PRECIPITATION AFTER 00Z THIS EVENING. PRECIPITATION WILL BLOSSOM SIGNIFICANTLY AROUND 06Z AS 50 KNOT LOW LEVEL JET CRANKS UP FROM CENTRAL TEXAS INTO OKLAHOMA. DEEP BAROCLINICITY WILL EXIST MAINLY NORTHEAST OF THE DDC CWA...WHICH IS WHY IT IS NO SURPRISE OMEGA FIELDS FROM ALL MODELS ARE THROUGH THE ROOF IN THIS AREA. THE LACK OF APPRECIABLE DEEP TROPOSPHERIC BAROCLINICITY OVER SOUTHWEST KANSAS WILL LIMIT SUBSTANTIAL PRECIPITATION AMOUNTS. THE BEST WINDOW FOR MEASURABLE PRECIPITATION WILL BE 03-09Z IT WOULD APPEAR. THIS "WAVE" OF PRECIPITATION WILL BE THE ONLY GOOD SHOT AT MEASURABLE PRECIP. AFTER 09Z...THE PRIMARY FOCUS FOR WIDESPREAD PRECIPITATION WILL HAVE MOVED RAPIDLY NORTHEAST INTO NEBRASKA AND IOWA AT THE NOSE OF THE EXTREMELY STRONG 65 KNOT LOW LEVEL JET. THIS IS THE PRECIPITATION AMOUNT/TIMING/DURATION PART OF THE FORECAST. NOW ON TO THE SURFACE TEMPERATURE AND PRECIPITATION TYPE PROBLEM... HAVE BEEN MONITORING HOURLY MSAS 3-HR PRESSURE TENDENCY AND OBSERVATIONS LIKE A HAWK THIS MORNING...AND COMPARING OBSERVED TEMPERATURES WITH MODEL TEMPERATURES. GFS AND NAM MODELS ARE INDEED STRUGGLING TO CAPTURE THE MAGNITUDE OF THE COLD AIR. 06Z SURFACE TEMPERATURES WERE OVER-FORECAST BY THE 6-HOUR NAM AND GFS BY 10 TO 12 DEGREES ACROSS CENTRAL NEBRASKA. THIS DOES NOT LEND HIGH CONFIDENCE IN EITHER OF THESE MODELS FOR SURFACE TEMPERATURE FORECASTING OVER THE NEXT 36 HOURS. THAT SAID...THE RUC13 IN AWIPS AND THE VARIOUS VERSIONS OF THE RUC ON THE FSL WEBSITE SHOW A MORE REALISTIC SURFACE TEMPERATURE FORECAST...SEVERAL DEGREES COLDER ACROSS WESTERN KANSAS...AND THE OFFICIAL FORECAST WILL MIRROR THE RUC13 SFC TEMP PREDICTION. HAVE LOWERED HIGHS TODAY BY A FEW DEGREES...AS ONCE THE COLD AIR GETS DOWN INTO SOUTHWEST KANSAS IN A FEW HOURS...NORTHEAST WINDS WILL LOCK THE MODIFIED ARCTIC AIR IN PLACE THROUGH THE DAY. HIGH LEVEL CLOUD COVER WILL MITIGATE DIRECT INSOLATION TO COUNTERACT SURFACE COLD ADVECTION...THUS AM EXPECTING LITTLE IF ANY DIURNAL RISE. BY EVENING...SURFACE TEMPERATURES WILL LIKELY BE IN THE 29-33 DEGREE RANGE FOR MOST OF THE DDC CWA AT PRECIPITATION ONSET...THUS THE PRIMARY PRECIP TYPE WILL BE FREEZING RAIN. THERE MAY ACTUALLY BE A LITTLE BIT OF SLEET AT THE ONSET OF PRECIPITATION BEFORE THE REALLY STRONG WARM ADVECTION KICKS IN AND THE WARM LAYER ALOFT REALLY INCREASES. UPSTREAM DEWPOINTS IN THE LOWER TEENS ALSO LEND THE LIKELIHOOD OF PRETTY DECENT WET-BULB EFFECT ON SURFACE TEMPERATURES AS WELL WHEN PRECIPITATION STARTS. THUS...AM EXPECTING A FAIRLY LARGE PART OF THE DDC CWA TO SEE AT LEAST SOME FREEZING RAIN THIS EVENING AND TONIGHT. THE MOST SUBSTANTIAL FREEZING RAIN WILL BE NORTH OF A JETMORE TO LARNED LINE UP TOWARDS THE INTERSTATE 70 CORRIDOR. AT THIS TIME...AM THINKING AROUND A TENTH TO TWO TENTHS OF AN INCH OF ICE ACCUMULATION...WITH PERHAPS A BIT MORE UP AROUND HAYS. WILL HOIST A FREEZING RAIN ADVISORY TO REPLACE THE WINTER STORM WATCH...FOR THE SAME COUNTIES. TREGO AND ELLIS COUNTY WILL HAVE TO BE WATCHED FOR POSSIBLE WARNING CRITERIA ICE ACCUMULATION, BUT AS IT APPEARS NOW...THE MOST SUBSTANTIAL ICE ACCUMULATIONS SHOULD REMAIN NORTHEAST OF DDC FORECAST AREA. LAST BUT NOT LEAST THE WIND. AS THE SUBTROPICAL SYSTEM EJECTS INTO COLORADO SATURDAY...VERY ROBUST LOW LEVEL RESPONSE WILL OCCUR WITH VERY DEEP CYCLOGENESIS. A BLEND OF THE GFS AND NAM BUFR PROFILE FOR A LOCATION SOUTH OF GRANADA COLORADO SUGGESTS A MEAN WIND IN THE MIXED LAYER OF 35 TO 40 KNOTS (SUSTAINED POTENTIAL) WITH WINDS AT THE TOP OF THE MIXED LAYER BETWEEN 50 AND 60 KNOTS (GUST POTENTIAL). THE GFS SHOWS THE MOST IMPRESSIVE DEEP MIXING UP TO 650MB AT THAT PARTICULAR BUFR SOUNDING LOCATION. THE HIGH WIND WATCH STILL LOOKS GOOD AND WILL KEEP IT IN PLACE...ALTHOUGH MY GUT FEELING IS THAT THE EASTERN PORTION OF THE CURRENT WATCH WILL PROBABLY FALL SHORT OF HIGH WIND WARNING CONDITIONS DUE TO LIKELY LACK OF DEEPER MIXING. IT STILL APPEARS THAT SUBSTANTIAL SURFACE WARMING WILL OCCUR FROM 15Z SATURDAY ON THROUGH THE REST OF THE DAY AS THE WARM FRONT RETREATS NORTHWARD. HIGHS IN THE LOWER 60S AS A RULE LOOK PRETTY GOOD FOR NOW ESPECIALLY SOUTHWEST ZONES. -UMSCHEID DAYS 3-7... MAIN FORECAST CHALLENGES FOR THIS EXTENDED PERIOD CONTINUE TO BE MAINLY TEMPERATURES. A STRONG COLD FRONT WILL BE MOVING THROUGH SOUTHWEST KANSAS ON SUNDAY MORNING WITH BREEZY TO WINDY CONDITIONS EARLY THEN AS THE HIGH PRESSURE RIDGE BUILDS IN THE WINDS SHOULD GO LIGHT BY AFTERNOON. SKIES SHOULD BE ONLY PARTLY CLOUDY WITH THE FRONTAL PASSAGE WITH LITTLE IN THE WAY OF LAYER MOISTURE WITH THIS SHORTWAVE TROUGH. THEN AS THE SHORTWAVE MOVES EAST LOOK FOR RISING MID LEVEL HEIGHTS AND A WARMING TREND. NORTHWEST FLOW ALOFT CAN BE EXPECTED INTO TUESDAY, THEN A SHORTWAVE TROUGH BRINGS A COLD FRONT INTO SOUTHWEST KANSAS ON WEDNESDAY INTO THURSDAY. THE NEW EC IS A BIT MORE AGGRESSIVE WITH THIS SHORTWAVE THAN THE GFS. HIGHS WILL BE MILD AND IN THE LOW 60S ON MONDAY, CLIMBING TO AROUND 70 BY TUESDAY, THEN WITH THE COLD FRONT HIGHS SHOULD BE IN THE 50S ON WEDNESDAY AND POSSIBLY ONLY 40S ON THURSDAY. HAVE LOWERED THURSDAY HIGHS WITH EXPECTED COOL RIDGE AND CLOUDY SKIES. MODELS HINT AT A BIT OF LIGHT PRECIP BUT WILL HOLD OFF FOR NOW AND MENTION A 10 POP. LOWS LOOK MILD ALSO IN THE MID 20S ON MONDAY MORNING THEN IN THE LOW TO MID 30S INTO THURSDAY MORNING AS DEWPOINTS INCREASE. && .AVIATION... EXPECT VFR CONDITIONS WITH A SURGE OF ARCTIC AIR MOVING INTO SOUTHWEST KANSAS EARLY THIS MORNING. WINDS WITH THIS SURGE WILL BE FROM THE NORTH AT 15 TO 22KTS EARLY, THEN BECOME EAST NORTHEASTERLY AND DECREASE. EXPECT INCREASING HIGH CLOUDS TODAY. CLOUDS WILL LOWER AND THICKEN TONIGHT WITH MVFR CIGS BY MIDNIGHT AND POSSIBLY IFR CIGS BY 12Z SATURDAY. LIGHT RAIN MAY BEGIN IN THE DDC AND GCK TERMINAL BY AROUND 00Z SATURDAY AND WITH SURFACE TEMPERATURES AROUND FREEZING SOME FREEZING RAIN OR RAIN IS ALSO EXPECTED AFTER MIDNIGHT INTO 12Z SATURDAY. FREEZING RAIN WILL BE THE MAIN TYPE AS YOU GO NORTH INTO THE HAYS REGION. && .PRELIMINARY POINT TEMPS/POPS... DDC 35 30 64 31 / 30 90 80 0 GCK 31 29 65 29 / 30 90 70 0 EHA 36 29 65 33 / 30 100 50 0 LBL 36 30 65 33 / 30 90 50 0 HYS 32 29 60 30 / 20 90 80 10 P28 40 35 62 39 / 30 90 80 0 && .DDC WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY FROM 6 PM CST /5 PM MST/ THIS EVENING TO 9 AM CST /8 AM MST/ SATURDAY FOR KSZ030-031-043>046-061>066- 074>079. HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR KSZ030-031-043>046-061>066-074>081-084>090. && $$ FN25/06/06 ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1013 PM EST FRI NOV 30 2007 .UPDATE... LES IS DIMINISHING OVER NW UPPER MI AS EXPECTED. OBS INDICATE PRONOUNCED CONVERGENCE OVER THE WRN PART OF THE LAKE WITH SSW WINDS AT SAXON HARBOR/ONTONAGON AND NW WINDS AT ISLE ROYALE AND THE KEWEENAW. ONTONAGON BRIEFLY SHIFTED NW AT 02Z BUT IS BACK TO SW NOW. EVEN SO...THERE AREN`T ANY DOMINANT BANDS SHOWING UP ON SATELLITE IMAGERY AS LOWERING INVERSION/DRY AIR ARE APPARENTLY NEGATIVELY IMPACTING LES. TO THE E...DOMINANT BAND...AIDED BY ENHANCED LAND BREEZE CONVERGENCE...HAS HAMMERED ERN PARTS OF ALGER COUNTY LATE AFTN/EARLY EVENING. SNOWFALL RATES WERE PROBABLY 2-3IN/HR. BAND HAS BEEN SLOWLY SHIFTING SW (NOW OVER MUNISING) WITH SLIGHT VEERING OF LOW-LEVEL WINDS THIS EVENING...BUT IT IS ALSO BEGINNING TO WEAKEN A BIT NOW. WIDE SEPARATION IS ALSO NOTED BTWN THE LES BANDS. GOING FCST APPEARS TO HAVE A GOOD HANDLE ON THE SITUATION OVERNIGHT...SO NO SIGNIFICANT CHANGES WILL BE MADE TO FCST. DOMINANT BAND IMPACTING ALGER COUNTY MAY SLIP A BIT FARTHER W INTO THE WRN PART OF THE COUNTY...BUT IT SHOULD CONTINUE TO WEAKEN GIVEN LOWERING INVERSION. THEN AS SFC HIGH PRES MOVES ACROSS THE AREA...ALLOWING LAND BREEZES TO BECOME EVEN MORE INFLUENTIAL...LES SHOULD BEGIN TO RETREAT CLOSER TO THE SHORELINES AND THEN ALMOST COMPLETELY OFFSHORE BY DAYBREAK. THIS INCLUDES NW UPPER MI AS WELL. EXPECT ADDITIONAL ACCUMULATIONS OVER THE ERN HEADLINE AREAS TO GENERALLY RANGE FROM 1 TO 4 INCHES...PROVIDED PRESENT WEAKENING TREND CONTINUES AS IT SHOULD. TO THE NW...ACCUMULATIONS SHOULD RANGE FROM 1 TO 2 INCHES. ELSEWHERE...WILL DROP MIN TEMPS OVER THE INTERIOR W AS OBS SHOW TEMPS FALLING TO NEAR OR BLO FCST MINS ALREADY (KLNL ALREADY FELL TO -8F AND KIMT -2F). STRATOCU FIELD HAS SPREAD WELL INLAND FROM LAKE SUPERIOR RECENTLY AND CAUSED TEMPS TO SPIKE BACK UP...BUT THERE MAY STILL BE A WINDOW FOR TEMPS TO PLUMMET AGAIN AFTER STRATOCU DEPARTS AND HIGH CLOUDS ARRIVE. MAY SEE -10F OR SO IN THE TYPICAL COLD SPOTS. && .PREV DISCUSSION (ISSUED 440 PM EST)... SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH UPR GRT LKS DOMINATED BY ARCTIC BRANCH TROFFING CENTERED OVER NW ONTARIO. VERY COLD AIRMASS UNDER THIS TROF...WITH 12Z H5/H85 TEMPS OF -40C/-31C AT YPL. PASSAGE OF THIS AIRMASS OVER THE RELATIVELY WARM WATERS OF LK SUP (ARND 4C) IN WNW FLOW BTWN HI PRES NR OMA AND LO PRES MOVING THRU SE ONTARIO HAS RESULTED IN NMRS WIND PARALLEL LES BANDS THAT ARE IMPACTING THOSE PORTIONS OF THE FA FVRD BY WNW LLVL FLOW. ALTHOUGH UPSTREAM AIRMASS IS DRY IN AN ABSOLUTE SENSE (12Z PWAT ONLY 0.06 INCH AT INL WITH SFC DWPTS ARND -10F)...AN INSPECTION OF THE INL AND YPL RAOBS AS WELL AS THE 13Z TAMDAR SDNG FM HIB INDICATES THE LLVLS ARE RELATIVELY MOIST. IN FACT...BACK EDGE OF LK SC IS NOT SEPARATING FM THE MN NORTH SHORE...SUGING DRYING IS NOT OVERWHELMING THE LES INTENSITY YET. SPOTTER REPORTS FM THE E ARND GRAND MARAIS INDICATE UP TO 3 INCHES OF SN FELL IN JUST 3 HOURS OR SO THERE THIS MRNG WHEN LES BAND CAME ASHORE. OVER THE SCNTRL...SKIES ARE GENERALLY CLR TO PCLDY WITH TEMPS WELL BLO NORMAL FOR THE SEASON (17Z WIND CHILL AS LO AS -18F AT IWD). AIRMASS FARTHER TO THE W CLOSER TO SFC HI PRES RDG IN THE PLAINS IS EVEN DRIER/MORE STABLE PER 12Z BIS/ABR SDNGS. A POTENT SHRTWV IN THE POLAR BRANCH FLOW IS DIGGING THRU CA (12HR H3 HGT FALLS CLOSE TO 200M) WITH ANOTHER SUBTROPICAL JET DISTURBANCE MOVING NEWD TOWARD THE DESERT SW. HI CLDS AHEAD OF THESE FEATURES ARE ALREADY STREAMING INTO THE CNTRL PLAINS...WITH A DECENT TAP OF TROPICAL MSTR FLOWING N AS SHOWN ON WV IMAGERY. SHORT TERM (TNGT/SAT)... MAIN FCST CONCERNS DURING THIS TIME ARE LES TRENDS/AMTS THRU TNGT. FOCUS ON SAT SHIFTS TO GATHERING STORM IN THE PLAINS ASSOCIATED WITH POLAR/SUBTROPICAL BRANCH DISTURBANCES UPSTREAM AND TIMING OF ANY ACCOMPANYING PCPN INTO THE FA. FOR TNGT...MODELS FCSTG 00Z-12Z H5 HGT RISES UP TO 100M OVER THE UPR GRT LKS BTWN DEPARTING ARCTIC BRANCH TROF AND DEEPENING TROF IN THE W ASSOCIATED WITH DISTURBANCES MENTIONED IN THE SYNOPSIS. ARRIVAL OF SFC HI PRES RDG UNDER THESE HGT RISES AS WELL AS DRIER/ MORE STABLE AIRMASS NOW OVER THE NCNTRL PLAINS SHOULD RESULT IN A GRADUAL DIMINISHING TREND TO THE LES/WINDS/BLSN TNGT. HOWEVER... LES WL LINGER THRU MOST OF THE NGT E OF P53 IN MORE PERSISTENT WNW FLOW. SINCE GFS/NAM/LOCAL HI RES MODEL RUNS SHOW FAIRLY SHARP LLVL CNVGC PERSISTING OVER THE E BTWN LARGER SCALE WNW FLOW AND DVLPG WSW LAND BREEZE FLOW OFF LAND TO THE N OF HI CENTER TRACKING THRU WI...WL CONTINUE GOING WINTER STORM WRNG FOR THE E. EARLIER RUNS HAD SHOWN PERSISTENT LAND BREEZE CNVGC WITH LARGER SCALE WNW FLOW IMPACTING ONTONAGON COUNTY THRU THIS EVNG...BUT LATEST OB FM ONTONAGON SHOWS THE WIND THERE HAS ALREADY SHIFTED TO THE SSW. SO ALLOWED GOING WRNG FOR THAT AREA TO EXPIRE AT 00Z AS SCHEDULED. SINCE THE EARLIER GUIDANCE SUGGESTED THE LAND BREEZE CNVGC AXIS WOULD SHIFT STEADILY N THRU TNGT AFTER STALLING OVER ONTONAGON COUNTY...LIMITING THE RESIDENCE TIME OVER THE KEWEENAW... ALLOWED GOING WRNG TO EXPIRE AT 00Z FOR KEWEENAW/NRN HOUGHTON AS WELL. BUT IF THE CNVGC AXIS PERSISTS FARTHER N...THE WRNG FOR THESE ZNS MAY HAVE TO BE EXTENDED. OTRW...WL TEND TOWARD THE LO END OF MOS GUIDANCE FOR TEMPS OVER THE INTERIOR AWAY FM LK MODERATION PER DRY AIRMASS UPSTREAM EVEN THOUGH SOME HI CLD MAY DRIFT IN LATE. MANY INTERIOR PLACES WL SEE SOME SUB ZERO MINS. ON SAT...LINGERING LES OVER THE KEWEENAW/ERN ZNS WL END SAT MRNG AS THE LARGER SCALE FLOW BACKS TO S BTWN DEPARTING HI PRES TO THE E AND DVLPG LO PRES IN THE PLAINS. THERE WL ALREADY BE QUITE A BIT OF MID/ HI CLD STREAMING INTO THE FA AT 12Z...AND THESE CLDS WL THEN LOWER AND THICKEN DURING THE DAY AS UPR DVGC IN RRQ OF RETREATING H3 JET MAX AND DVLPG DEEP LYR ISENTROPIC LIFT AS SHOWN ON THE GFS FCST 280K-310K SFCS. NAM IS SLOWER THAN THE GFS WITH THE DVLPMNT OF THESE FEATURES...BUT NCEP PREFERS THE FASTER GFS. WENT LIKELY POPS NEAR THE WI BORDER AFT 18Z CLOSER TO THE DEEPER MSTR/SHARPER DYNAMICS AND/OR WHERE SE UPSLOPE FLOW OFF LK MI MIGHT ENHANCE MOISTENING. BUT TENDED TO GO SLOWER INTRODUCING THE HIER POPS FARTHER NE AS GFS SHOWS SHARPER H8-6 FGEN/UPR DVGC TENDING TO REMAIN TO THE S THRU SAT AFTN. UP TO 2-3 INCHES OF SN MAY ACCUMULATE ALONG THE WI BORDER BY 00Z SUN. LONG TERM (SAT NIGHT THRU FRI)... THE MAIN FORECAST DILEMMA CONTINUES TO BE THE POTENTIAL FOR HEAVY SNOW AND POSSIBLY MIXED PRECIPITATION SATURDAY NIGHT AND SUNDAY. 06Z GFS HAD THE SURFACE LOW OVER S-SW WISCONSIN AT 12Z SUNDAY. THE 12Z NAM WAS SLIGHTLY SLOWER...WITH THE LOW STILL OVER S-CENTRAL IOWA. IN FACT...IT IS ABOUT 4 TO 6 HOURS SLOWER THAN THE GFS. THIS COULD MAKE A SIGNIFICANT DIFFERENCE IN TIMING OF HEAVY SNOW OR MIXED PRECIPITATION OVER THE REGION. TAKING THIS TIMING DIFFERENCE INTO ACCOUNT...THE 540 LINE IS LOCATED IN SIMILAR LOCATIONS...ENCOMPASSING ALL OF THE U.P. EXCLUDING KEWEENAW COUNTY AND POSSIBLY THE NORTHERN TIP OF LUCE COUNTY. WILL NEED TO KEEP THIS IN MIND AS WE FIGURE OUT THE TYPE OF PRECIPITATION POSSIBLE SATURDAY NIGHT AND SUNDAY. EITHER WAY...AFTER 03Z MONDAY...SNOW WILL DOMINATE UPPER MICHIGAN AS WINDS BECOMING NORTHWESTERLY WITH THE SURFACE LOW SLIDES EASTWARD INTO LAKE HURON AND EXTREME SOUTHEASTERN ONTARIO. WHEN COMPARING THE TRACK OF THIS SURFACE LOW WITH THE CAN/ECMWF/UKMET/GFS/NAM...THE NAM WAS INDEED MUCH SLOWER. AS A RESULT OF THIS AND THE FACT THAT IT WAS NOTED IN THE PREVIOUS DISCUSSION THAT IT WAS ONE OF THE FARTHER SE MODELS....WITH LIMITED RUN TO RUN CONSISTENCY...IT WAS DISCREDITED AND NOT USED IN THIS FORECAST PACKAGE BEYOND 00Z SUNDAY. AT 00Z MONDAY...THERE WERE GENERALLY 3 TRAINS OF THOUGHT...THE AFOREMENTIONED SLOW NAM...THE MORE NORTHERN AND CONSISTENTLY DEEPER UKMET/CANADIAN...AND THE QUICKER GFS/ECMWF. WILL HEDGE THE FORECAST TO THE GFS/ECMWF WITH SOME THOUGHT GIVEN TO THE BLEND OF THE CANADIAN/UKMET. SO...FORECAST WISE...WILL INCREASE TEMPERATURES SLIGHTLY FOR SUNDAY MORNING ON OUR STRENGTHENING SOUTHEASTERLY AND PLENTY OF CLOUD COVER. ELEVATED WARM LAYER ACROSS THE SOUTHERN HALF OF THE CWA MAY POSE A PROBLEM FOR MIXED PRECIPITATION...AS POCKET 0 TO -2C BETWEEN 700 AND 800MB SHOWS UP FROM 09Z-17Z SUNDAY AFTERNOON AT IMT WITH SFC TEMPS NEAR OR JUST ABOVE FREEZING. SO HAVE UTILIZED THE 750MB GFS TEMPS HEAVILY WHEN FIGURING OUT WEATHER FOR...SINCE THE SNOW GROWTH REGION IS BETWEEN 500 AND 600MB. EXPECT TEMPERATURES TO MAX OUT RIGHT AROUND 18Z...SO JUST SLIGHTLY BEFORE CLIMATOLOGICAL NORM. STILL...BY THIS TIME...MUCH OF THE ACCUMULATED SNOW WILL HAVE FALLEN. AS A RESULT...WARNINGS SEEM LIKELY. LOOKING AT MONDAY NIGHT/00Z TUESDAY THE 06Z GFS IS SLOWER THAN THE 00Z ECMWF TO PUSH THE 500MB CLOSED LOW EASTWARD TO THE NEW ENGLAND STATES...COMING MORE IN LINE WITH EACH OTHER BY 00Z WEDNESDAY FOR AT LEAST THE LOCATION OF THE 500MB LOW. HOWEVER...CLOSER TO HOME THE NEXT EMBEDDED TROUGH IN THIS LARGE SCALE FEATURE CAN BE EXPECTED TO SLIDE SOUTHWARD FROM NORTHERN ONTARIO TO NORTHERN LAKE SUPERIOR BY 00Z WEDNESDAY. THE 06Z GFS IS STRONGER/DEEPER WITH THIS NEXT SYSTEM. THE 06Z GFS...WITH ITS STRONGER TROUGH...KEEPS THE GENERAL TROUGHINESS OVER THE REGION THROUGH THURSDAY NIGHT INTO EARLY NEXT FRIDAY. ON THE OTHER HAND...WITH AN OVERALL WEAKER RENDITION...THE 00Z ECMWF WOULD ALLOW FOR SMALL SCALE RIDGING FOR A MAJORITY OF THE TIME FROM TUESDAY AFTERNOON ON. SO...THERE ARE SIGNIFICANT DIFFERENCES IN MODEL GUIDANCE OVER UPPER MICHIGAN. HPC GUIDANCE WAS HEAVILY UTILIZED...FOR DAYS 4/TUESDAY THROUGH 7/FRIDAY. THIS DID NOT INCLUDE THE 00Z CANADIAN...BUT WAS INSTEAD THE 00Z ECMWF EARLY IN THE PERIOD BEFORE A 50/50 BLEND OF THE 00Z ECMWF/NCEP ENSEMBLE MEAN FROM WEDNESDAY MORNING ONWARD...WITH PLENTY OF UNCERTAINTY IN THE LATER PART OF THE FORECAST PERIOD. WHAT IS MORE CERTAIN IS BELOW TO WELL BELOW AVG TEMPS WILL EXTEND FROM OUR REGION THROUGH THE SOUTHEASTERN UNITED STATES MIDWEEK. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KSAW...VFR CONDITIONS WILL PREVAIL UNTIL NEARLY THE END OF THIS FCST PERIOD. APPROACHING WINTER STORM SAT SHOULD RESULT IN A QUICK LOWERING OF CIGS/VIS TO MVFR/IFR LATE IN THE AFTN AS SNOW OVERSPREADS THE AREA. AT KCMX...FINALLY...IMPROVEMENT WILL BEGIN THIS EVENING AS LAKE EFFECT SHSN DIMINISH DUE TO HIGH PRES DRIFTING OVER THE AREA. EXPECT A RAPID DECREASE IN WINDS OVER THE NEXT FEW HRS...ENDING BLSN. CIGS HAVE ALREADY LIFTED TO VFR...BUT THAT PROBABLY WON`T BE THE PREDOMINANT CONDITION AS INVERSION LOWERS UNDER APPROACHING HIGH PRES. WILL OPT FOR MVFR CIGS FOR MOST OF THE NIGHT. HAVE TO BELIEVE THE VLIFR VIS CONDITIONS WILL END SHORTLY AS WINDS/SNOW DIMINISH. BY THE END OF THE EVENING...EXPECT MVFR VIS AND OCCASIONAL IFR. SHSN SHOULD END LATE IN THE NIGHT AS WINDS GO VRBL THEN SSE. VFR CONDITIONS WILL THEN BE THE RULE UNTIL LEADING EDGE OF APPROACHING WINTER STORM ARRIVES AT THE END OF THE AFTN. MDT/HVY SNOW AND LIFR POSSIBLE VLIFR CONDITIONS WILL DEVELOP SAT EVENING AT KSAW/KCMX...JUST BEYOND THIS FCST PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER EASTERN ONTARIO TO MOVE TO MAINE TONIGHT AS HIGH PRESSURE OVER THE CENTRAL PLAINS MOVES TO THE OHIO VALLEY AND GREAT LAKES. LINGERING WNW GALES THIS EVNG WILL DIMINISH BY MIDNGT AS THE WEAKER PRES GRADIENT ASSOCIATED WITH THE HIGH PUSHES EWD. THE HIGH WILL REACH WESTERN QUEBEC BY SATURDAY EVENING AS A LOW PRESSURE OF 29.2 INCHES OVER THE CENTRAL PLAINS SATURDAY EVENING REACHES LAKE MICHIGAN SUNDAY AFTERNOON. THERE WILL LIKELY BE ANOTHER ESE GALE SAT NGT INTO SUN AS THIS LOW GRINDS INTO HI PRES TO THE NE AND SHARPENS THE PRES GRADIENT OVER THE UPR LKS. THE LOW WILL THEN REACH THE EASTERN GREAT LAKES BY MONDAY MORNING AS ANOTHER HIGH PRESSURE RIDGE MOVES INTO THE PLAINS. ANOTHER N GALE EVENT IS LIKELY SUN NIGHT INTO MONDAY IN THE TIGHT PRES GRADIENT BETWEEN THESE FEATURES. THE RIDGE WILL THEN MOVE TO THE EASTERN GREAT LAKES WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM MAKES ITS WAY FROM ALBERTA TO SOUTHERN LAKE MICHIGAN. ATTM...EXPECT N WINDS TO 30 KTS AS THE PRES GRADIENT TIGHTENS OVER THE UPR LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING FROM 7 PM SATURDAY TO 1 PM EST SUN MIZ001-003>007-014-085. WINTER STORM WARNING FROM 1 PM EST /12 PM CST/ SAT TO 1 PM EST /12 PM CST/ SUN MIZ002-009>013-084. LAKE EFFECT SNOW ADVY UNTIL 3 AM EST SAT MIZ085. WINTER STORM WARNING UNTIL 5 AM EST SAT MIZ006-007. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 635 PM EST FRI NOV 30 2007 UPDATED AVIATION DISCUSSION FOR 00Z TAFS .SYNOPSIS (ISSUED AT 440 PM EST)... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH UPR GRT LKS DOMINATED BY ARCTIC BRANCH TROFFING CENTERED OVER NW ONTARIO. VERY COLD AIRMASS UNDER THIS TROF...WITH 12Z H5/H85 TEMPS OF -40C/-31C AT YPL. PASSAGE OF THIS AIRMASS OVER THE RELATIVELY WARM WATERS OF LK SUP (ARND 4C) IN WNW FLOW BTWN HI PRES NR OMA AND LO PRES MOVING THRU SE ONTARIO HAS RESULTED IN NMRS WIND PARALLEL LES BANDS THAT ARE IMPACTING THOSE PORTIONS OF THE FA FVRD BY WNW LLVL FLOW. ALTHOUGH UPSTREAM AIRMASS IS DRY IN AN ABSOLUTE SENSE (12Z PWAT ONLY 0.06 INCH AT INL WITH SFC DWPTS ARND -10F)...AN INSPECTION OF THE INL AND YPL RAOBS AS WELL AS THE 13Z TAMDAR SDNG FM HIB INDICATES THE LLVLS ARE RELATIVELY MOIST. IN FACT...BACK EDGE OF LK SC IS NOT SEPARATING FM THE MN NORTH SHORE...SUGING DRYING IS NOT OVERWHELMING THE LES INTENSITY YET. SPOTTER REPORTS FM THE E ARND GRAND MARAIS INDICATE UP TO 3 INCHES OF SN FELL IN JUST 3 HOURS OR SO THERE THIS MRNG WHEN LES BAND CAME ASHORE. OVER THE SCNTRL...SKIES ARE GENERALLY CLR TO PCLDY WITH TEMPS WELL BLO NORMAL FOR THE SEASON (17Z WIND CHILL AS LO AS -18F AT IWD). AIRMASS FARTHER TO THE W CLOSER TO SFC HI PRES RDG IN THE PLAINS IS EVEN DRIER/MORE STABLE PER 12Z BIS/ABR SDNGS. A POTENT SHRTWV IN THE POLAR BRANCH FLOW IS DIGGING THRU CA (12HR H3 HGT FALLS CLOSE TO 200M) WITH ANOTHER SUBTROPICAL JET DISTURBANCE MOVING NEWD TOWARD THE DESERT SW. HI CLDS AHEAD OF THESE FEATURES ARE ALREADY STREAMING INTO THE CNTRL PLAINS...WITH A DECENT TAP OF TROPICAL MSTR FLOWING N AS SHOWN ON WV IMAGERY. && .SHORT TERM (TNGT/SAT ISSUED AT 440 PM EST)... MAIN FCST CONCERNS DURING THIS TIME ARE LES TRENDS/AMTS THRU TNGT. FOCUS ON SAT SHIFTS TO GATHERING STORM IN THE PLAINS ASSOCIATED WITH POLAR/SUBTROPICAL BRANCH DISTURBANCES UPSTREAM AND TIMING OF ANY ACCOMPANYING PCPN INTO THE FA. FOR TNGT...MODELS FCSTG 00Z-12Z H5 HGT RISES UP TO 100M OVER THE UPR GRT LKS BTWN DEPARTING ARCTIC BRANCH TROF AND DEEPENING TROF IN THE W ASSOCIATED WITH DISTURBANCES MENTIONED IN THE SYNOPSIS. ARRIVAL OF SFC HI PRES RDG UNDER THESE HGT RISES AS WELL AS DRIER/ MORE STABLE AIRMASS NOW OVER THE NCNTRL PLAINS SHOULD RESULT IN A GRADUAL DIMINISHING TREND TO THE LES/WINDS/BLSN TNGT. HOWEVER... LES WL LINGER THRU MOST OF THE NGT E OF P53 IN MORE PERSISTENT WNW FLOW. SINCE GFS/NAM/LOCAL HI RES MODEL RUNS SHOW FAIRLY SHARP LLVL CNVGC PERSISTING OVER THE E BTWN LARGER SCALE WNW FLOW AND DVLPG WSW LAND BREEZE FLOW OFF LAND TO THE N OF HI CENTER TRACKING THRU WI...WL CONTINUE GOING WINTER STORM WRNG FOR THE E. EARLIER RUNS HAD SHOWN PERSISTENT LAND BREEZE CNVGC WITH LARGER SCALE WNW FLOW IMPACTING ONTONAGON COUNTY THRU THIS EVNG...BUT LATEST OB FM ONTONAGON SHOWS THE WIND THERE HAS ALREADY SHIFTED TO THE SSW. SO ALLOWED GOING WRNG FOR THAT AREA TO EXPIRE AT 00Z AS SCHEDULED. SINCE THE EARLIER GUIDANCE SUGGESTED THE LAND BREEZE CNVGC AXIS WOULD SHIFT STEADILY N THRU TNGT AFTER STALLING OVER ONTONAGON COUNTY...LIMITING THE RESIDENCE TIME OVER THE KEWEENAW... ALLOWED GOING WRNG TO EXPIRE AT 00Z FOR KEWEENAW/NRN HOUGHTON AS WELL. BUT IF THE CNVGC AXIS PERSISTS FARTHER N...THE WRNG FOR THESE ZNS MAY HAVE TO BE EXTENDED. OTRW...WL TEND TOWARD THE LO END OF MOS GUIDANCE FOR TEMPS OVER THE INTERIOR AWAY FM LK MODERATION PER DRY AIRMASS UPSTREAM EVEN THOUGH SOME HI CLD MAY DRIFT IN LATE. MANY INTERIOR PLACES WL SEE SOME SUB ZERO MINS. ON SAT...LINGERING LES OVER THE KEWEENAW/ERN ZNS WL END SAT MRNG AS THE LARGER SCALE FLOW BACKS TO S BTWN DEPARTING HI PRES TO THE E AND DVLPG LO PRES IN THE PLAINS. THERE WL ALREADY BE QUITE A BIT OF MID/ HI CLD STREAMING INTO THE FA AT 12Z...AND THESE CLDS WL THEN LOWER AND THICKEN DURING THE DAY AS UPR DVGC IN RRQ OF RETREATING H3 JET MAX AND DVLPG DEEP LYR ISENTROPIC LIFT AS SHOWN ON THE GFS FCST 280K-310K SFCS. NAM IS SLOWER THAN THE GFS WITH THE DVLPMNT OF THESE FEATURES...BUT NCEP PREFERS THE FASTER GFS. WENT LIKELY POPS NEAR THE WI BORDER AFT 18Z CLOSER TO THE DEEPER MSTR/SHARPER DYNAMICS AND/OR WHERE SE UPSLOPE FLOW OFF LK MI MIGHT ENHANCE MOISTENING. BUT TENDED TO GO SLOWER INTRODUCING THE HIER POPS FARTHER NE AS GFS SHOWS SHARPER H8-6 FGEN/UPR DVGC TENDING TO REMAIN TO THE S THRU SAT AFTN. UP TO 2-3 INCHES OF SN MAY ACCUMULATE ALONG THE WI BORDER BY 00Z SUN. .LONG TERM (SAT NIGHT THRU FRI ISSUED AT 440 PM EST)... THE MAIN FORECAST DILEMMA CONTINUES TO BE THE POTENTIAL FOR HEAVY SNOW AND POSSIBLY MIXED PRECIPITATION SATURDAY NIGHT AND SUNDAY. 06Z GFS HAD THE SURFACE LOW OVER S-SW WISCONSIN AT 12Z SUNDAY. THE 12Z NAM WAS SLIGHTLY SLOWER...WITH THE LOW STILL OVER S-CENTRAL IOWA. IN FACT...IT IS ABOUT 4 TO 6 HOURS SLOWER THAN THE GFS. THIS COULD MAKE A SIGNIFICANT DIFFERENCE IN TIMING OF HEAVY SNOW OR MIXED PRECIPITATION OVER THE REGION. TAKING THIS TIMING DIFFERENCE INTO ACCOUNT...THE 540 LINE IS LOCATED IN SIMILAR LOCATIONS...ENCOMPASSING ALL OF THE U.P. EXCLUDING KEWEENAW COUNTY AND POSSIBLY THE NORTHERN TIP OF LUCE COUNTY. WILL NEED TO KEEP THIS IN MIND AS WE FIGURE OUT THE TYPE OF PRECIPITATION POSSIBLE SATURDAY NIGHT AND SUNDAY. EITHER WAY...AFTER 03Z MONDAY...SNOW WILL DOMINATE UPPER MICHIGAN AS WINDS BECOMING NORTHWESTERLY WITH THE SURFACE LOW SLIDES EASTWARD INTO LAKE HURON AND EXTREME SOUTHEASTERN ONTARIO. WHEN COMPARING THE TRACK OF THIS SURFACE LOW WITH THE CAN/ECMWF/UKMET/GFS/NAM...THE NAM WAS INDEED MUCH SLOWER. AS A RESULT OF THIS AND THE FACT THAT IT WAS NOTED IN THE PREVIOUS DISCUSSION THAT IT WAS ONE OF THE FARTHER SE MODELS....WITH LIMITED RUN TO RUN CONSISTENCY...IT WAS DISCREDITED AND NOT USED IN THIS FORECAST PACKAGE BEYOND 00Z SUNDAY. AT 00Z MONDAY...THERE WERE GENERALLY 3 TRAINS OF THOUGHT...THE AFOREMENTIONED SLOW NAM...THE MORE NORTHERN AND CONSISTENTLY DEEPER UKMET/CANADIAN...AND THE QUICKER GFS/ECMWF. WILL HEDGE THE FORECAST TO THE GFS/ECMWF WITH SOME THOUGHT GIVEN TO THE BLEND OF THE CANADIAN/UKMET. SO...FORECAST WISE...WILL INCREASE TEMPERATURES SLIGHTLY FOR SUNDAY MORNING ON OUR STRENGTHENING SOUTHEASTERLY AND PLENTY OF CLOUD COVER. ELEVATED WARM LAYER ACROSS THE SOUTHERN HALF OF THE CWA MAY POSE A PROBLEM FOR MIXED PRECIPITATION...AS POCKET 0 TO -2C BETWEEN 700 AND 800MB SHOWS UP FROM 09Z-17Z SUNDAY AFTERNOON AT IMT WITH SFC TEMPS NEAR OR JUST ABOVE FREEZING. SO HAVE UTILIZED THE 750MB GFS TEMPS HEAVILY WHEN FIGURING OUT WEATHER FOR...SINCE THE SNOW GROWTH REGION IS BETWEEN 500 AND 600MB. EXPECT TEMPERATURES TO MAX OUT RIGHT AROUND 18Z...SO JUST SLIGHTLY BEFORE CLIMATOLOGICAL NORM. STILL...BY THIS TIME...MUCH OF THE ACCUMULATED SNOW WILL HAVE FALLEN. AS A RESULT...WARNINGS SEEM LIKELY. LOOKING AT MONDAY NIGHT/00Z TUESDAY THE 06Z GFS IS SLOWER THAN THE 00Z ECMWF TO PUSH THE 500MB CLOSED LOW EASTWARD TO THE NEW ENGLAND STATES...COMING MORE IN LINE WITH EACH OTHER BY 00Z WEDNESDAY FOR AT LEAST THE LOCATION OF THE 500MB LOW. HOWEVER...CLOSER TO HOME THE NEXT EMBEDDED TROUGH IN THIS LARGE SCALE FEATURE CAN BE EXPECTED TO SLIDE SOUTHWARD FROM NORTHERN ONTARIO TO NORTHERN LAKE SUPERIOR BY 00Z WEDNESDAY. THE 06Z GFS IS STRONGER/DEEPER WITH THIS NEXT SYSTEM. THE 06Z GFS...WITH ITS STRONGER TROUGH...KEEPS THE GENERAL TROUGHINESS OVER THE REGION THROUGH THURSDAY NIGHT INTO EARLY NEXT FRIDAY. ON THE OTHER HAND...WITH AN OVERALL WEAKER RENDITION...THE 00Z ECMWF WOULD ALLOW FOR SMALL SCALE RIDGING FOR A MAJORITY OF THE TIME FROM TUESDAY AFTERNOON ON. SO...THERE ARE SIGNIFICANT DIFFERENCES IN MODEL GUIDANCE OVER UPPER MICHIGAN. HPC GUIDANCE WAS HEAVILY UTILIZED...FOR DAYS 4/TUESDAY THROUGH 7/FRIDAY. THIS DID NOT INCLUDE THE 00Z CANADIAN...BUT WAS INSTEAD THE 00Z ECMWF EARLY IN THE PERIOD BEFORE A 50/50 BLEND OF THE 00Z ECMWF/NCEP ENSEMBLE MEAN FROM WEDNESDAY MORNING ONWARD...WITH PLENTY OF UNCERTAINTY IN THE LATER PART OF THE FORECAST PERIOD. WHAT IS MORE CERTAIN IS BELOW TO WELL BELOW AVG TEMPS WILL EXTEND FROM OUR REGION THROUGH THE SOUTHEASTERN UNITED STATES MIDWEEK. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KSAW...VFR CONDITIONS WILL PREVAIL UNTIL NEARLY THE END OF THIS FCST PERIOD. APPROACHING WINTER STORM SAT SHOULD RESULT IN A QUICK LOWERING OF CIGS/VIS TO MVFR/IFR LATE IN THE AFTN AS SNOW OVERSPREADS THE AREA. AT KCMX...FINALLY...IMPROVEMENT WILL BEGIN THIS EVENING AS LAKE EFFECT SHSN DIMINISH DUE TO HIGH PRES DRIFTING OVER THE AREA. EXPECT A RAPID DECREASE IN WINDS OVER THE NEXT FEW HRS...ENDING BLSN. CIGS HAVE ALREADY LIFTED TO VFR...BUT THAT PROBABLY WON`T BE THE PREDOMINANT CONDITION AS INVERSION LOWERS UNDER APPROACHING HIGH PRES. WILL OPT FOR MVFR CIGS FOR MOST OF THE NIGHT. HAVE TO BELIEVE THE VLIFR VIS CONDITIONS WILL END SHORTLY AS WINDS/SNOW DIMINISH. BY THE END OF THE EVENING...EXPECT MVFR VIS AND OCCASIONAL IFR. SHSN SHOULD END LATE IN THE NIGHT AS WINDS GO VRBL THEN SSE. VFR CONDITIONS WILL THEN BE THE RULE UNTIL LEADING EDGE OF APPROACHING WINTER STORM ARRIVES AT THE END OF THE AFTN. MDT/HVY SNOW AND LIFR POSSIBLE VLIFR CONDITIONS WILL DEVELOP SAT EVENING AT KSAW/KCMX...JUST BEYOND THIS FCST PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER EASTERN ONTARIO TO MOVE TO MAINE TONIGHT AS HIGH PRESSURE OVER THE CENTRAL PLAINS MOVES TO THE OHIO VALLEY AND GREAT LAKES. LINGERING WNW GALES THIS EVNG WILL DIMINISH BY MIDNGT AS THE WEAKER PRES GRADIENT ASSOCIATED WITH THE HIGH PUSHES EWD. THE HIGH WILL REACH WESTERN QUEBEC BY SATURDAY EVENING AS A LOW PRESSURE OF 29.2 INCHES OVER THE CENTRAL PLAINS SATURDAY EVENING REACHES LAKE MICHIGAN SUNDAY AFTERNOON. THERE WILL LIKELY BE ANOTHER ESE GALE SAT NGT INTO SUN AS THIS LOW GRINDS INTO HI PRES TO THE NE AND SHARPENS THE PRES GRADIENT OVER THE UPR LKS. THE LOW WILL THEN REACH THE EASTERN GREAT LAKES BY MONDAY MORNING AS ANOTHER HIGH PRESSURE RIDGE MOVES INTO THE PLAINS. ANOTHER N GALE EVENT IS LIKELY SUN NIGHT INTO MONDAY IN THE TIGHT PRES GRADIENT BETWEEN THESE FEATURES. THE RIDGE WILL THEN MOVE TO THE EASTERN GREAT LAKES WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM MAKES ITS WAY FROM ALBERTA TO SOUTHERN LAKE MICHIGAN. ATTM...EXPECT N WINDS TO 30 KTS AS THE PRES GRADIENT TIGHTENS OVER THE UPR LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING FROM 7 PM SATURDAY TO 1 PM EST SUN MIZ001-003>007-014-085. WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING MIZ001>003. WINTER STORM WARNING FROM 1 PM EST /12 PM CST/ SAT TO 1 PM EST /12 PM CST/ SUN MIZ002-009>013-084. LAKE EFFECT SNOW ADVY UNTIL 3 AM EST SAT MIZ085. WINTER STORM WARNING UNTIL 5 AM EST SAT MIZ006-007. LAKE SUPERIOR...GALE WARNING UNTIL 9 PM EST THIS EVENING LSZ249>251-265>267. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 440 PM EST FRI NOV 30 2007 .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH UPR GRT LKS DOMINATED BY ARCTIC BRANCH TROFFING CENTERED OVER NW ONTARIO. VERY COLD AIRMASS UNDER THIS TROF...WITH 12Z H5/H85 TEMPS OF -40C/-31C AT YPL. PASSAGE OF THIS AIRMASS OVER THE RELATIVELY WARM WATERS OF LK SUP (ARND 4C) IN WNW FLOW BTWN HI PRES NR OMA AND LO PRES MOVING THRU SE ONTARIO HAS RESULTED IN NMRS WIND PARALLEL LES BANDS THAT ARE IMPACTING THOSE PORTIONS OF THE FA FVRD BY WNW LLVL FLOW. ALTHOUGH UPSTREAM AIRMASS IS DRY IN AN ABSOLUTE SENSE (12Z PWAT ONLY 0.06 INCH AT INL WITH SFC DWPTS ARND -10F)...AN INSPECTION OF THE INL AND YPL RAOBS AS WELL AS THE 13Z TAMDAR SDNG FM HIB INDICATES THE LLVLS ARE RELATIVELY MOIST. IN FACT...BACK EDGE OF LK SC IS NOT SEPARATING FM THE MN NORTH SHORE...SUGING DRYING IS NOT OVERWHELMING THE LES INTENSITY YET. SPOTTER REPORTS FM THE E ARND GRAND MARAIS INDICATE UP TO 3 INCHES OF SN FELL IN JUST 3 HOURS OR SO THERE THIS MRNG WHEN LES BAND CAME ASHORE. OVER THE SCNTRL...SKIES ARE GENERALLY CLR TO PCLDY WITH TEMPS WELL BLO NORMAL FOR THE SEASON (17Z WIND CHILL AS LO AS -18F AT IWD). AIRMASS FARTHER TO THE W CLOSER TO SFC HI PRES RDG IN THE PLAINS IS EVEN DRIER/MORE STABLE PER 12Z BIS/ABR SDNGS. A POTENT SHRTWV IN THE POLAR BRANCH FLOW IS DIGGING THRU CA (12HR H3 HGT FALLS CLOSE TO 200M) WITH ANOTHER SUBTROPICAL JET DISTURBANCE MOVING NEWD TOWARD THE DESERT SW. HI CLDS AHEAD OF THESE FEATURES ARE ALREADY STREAMING INTO THE CNTRL PLAINS...WITH A DECENT TAP OF TROPICAL MSTR FLOWING N AS SHOWN ON WV IMAGERY. && .SHORT TERM DISCUSSION (TNGT/SAT)... MAIN FCST CONCERNS DURING THIS TIME ARE LES TRENDS/AMTS THRU TNGT. FOCUS ON SAT SHIFTS TO GATHERING STORM IN THE PLAINS ASSOCIATED WITH POLAR/SUBTROPICAL BRANCH DISTURBANCES UPSTREAM AND TIMING OF ANY ACCOMPANYING PCPN INTO THE FA. FOR TNGT...MODELS FCSTG 00Z-12Z H5 HGT RISES UP TO 100M OVER THE UPR GRT LKS BTWN DEPARTING ARCTIC BRANCH TROF AND DEEPENING TROF IN THE W ASSOCIATED WITH DISTURBANCES MENTIONED IN THE SYNOPSIS. ARRIVAL OF SFC HI PRES RDG UNDER THESE HGT RISES AS WELL AS DRIER/ MORE STABLE AIRMASS NOW OVER THE NCNTRL PLAINS SHOULD RESULT IN A GRADUAL DIMINISHING TREND TO THE LES/WINDS/BLSN TNGT. HOWEVER... LES WL LINGER THRU MOST OF THE NGT E OF P53 IN MORE PERSISTENT WNW FLOW. SINCE GFS/NAM/LOCAL HI RES MODEL RUNS SHOW FAIRLY SHARP LLVL CNVGC PERSISTING OVER THE E BTWN LARGER SCALE WNW FLOW AND DVLPG WSW LAND BREEZE FLOW OFF LAND TO THE N OF HI CENTER TRACKING THRU WI...WL CONTINUE GOING WINTER STORM WRNG FOR THE E. EARLIER RUNS HAD SHOWN PERSISTENT LAND BREEZE CNVGC WITH LARGER SCALE WNW FLOW IMPACTING ONTONAGON COUNTY THRU THIS EVNG...BUT LATEST OB FM ONTONAGON SHOWS THE WIND THERE HAS ALREADY SHIFTED TO THE SSW. SO ALLOWED GOING WRNG FOR THAT AREA TO EXPIRE AT 00Z AS SCHEDULED. SINCE THE EARLIER GUIDANCE SUGGESTED THE LAND BREEZE CNVGC AXIS WOULD SHIFT STEADILY N THRU TNGT AFTER STALLING OVER ONTONAGON COUNTY...LIMITING THE RESIDENCE TIME OVER THE KEWEENAW... ALLOWED GOING WRNG TO EXPIRE AT 00Z FOR KEWEENAW/NRN HOUGHTON AS WELL. BUT IF THE CNVGC AXIS PERSISTS FARTHER N...THE WRNG FOR THESE ZNS MAY HAVE TO BE EXTENDED. OTRW...WL TEND TOWARD THE LO END OF MOS GUIDANCE FOR TEMPS OVER THE INTERIOR AWAY FM LK MODERATION PER DRY AIRMASS UPSTREAM EVEN THOUGH SOME HI CLD MAY DRIFT IN LATE. MANY INTERIOR PLACES WL SEE SOME SUB ZERO MINS. ON SAT...LINGERING LES OVER THE KEWEENAW/ERN ZNS WL END SAT MRNG AS THE LARGER SCALE FLOW BACKS TO S BTWN DEPARTING HI PRES TO THE E AND DVLPG LO PRES IN THE PLAINS. THERE WL ALREADY BE QUITE A BIT OF MID/ HI CLD STREAMING INTO THE FA AT 12Z...AND THESE CLDS WL THEN LOWER AND THICKEN DURING THE DAY AS UPR DVGC IN RRQ OF RETREATING H3 JET MAX AND DVLPG DEEP LYR ISENTROPIC LIFT AS SHOWN ON THE GFS FCST 280K-310K SFCS. NAM IS SLOWER THAN THE GFS WITH THE DVLPMNT OF THESE FEATURES...BUT NCEP PREFERS THE FASTER GFS. WENT LIKELY POPS NEAR THE WI BORDER AFT 18Z CLOSER TO THE DEEPER MSTR/SHARPER DYNAMICS AND/OR WHERE SE UPSLOPE FLOW OFF LK MI MIGHT ENHANCE MOISTENING. BUT TENDED TO GO SLOWER INTRODUCING THE HIER POPS FARTHER NE AS GFS SHOWS SHARPER H8-6 FGEN/UPR DVGC TENDING TO REMAIN TO THE S THRU SAT AFTN. UP TO 2-3 INCHES OF SN MAY ACCUMULATE ALONG THE WI BORDER BY 00Z SUN. && .LONG TERM (TOMORROW NIGHT THROUGH FRIDAY)... THE MAIN FORECAST DILEMMA CONTINUES TO BE THE POTENTIAL FOR HEAVY SNOW AND POSSIBLY MIXED PRECIPITATION SATURDAY NIGHT AND SUNDAY. 06Z GFS HAD THE SURFACE LOW OVER S-SW WISCONSIN AT 12Z SUNDAY. THE 12Z NAM WAS SLIGHTLY SLOWER...WITH THE LOW STILL OVER S-CENTRAL IOWA. IN FACT...IT IS ABOUT 4 TO 6 HOURS SLOWER THAN THE GFS. THIS COULD MAKE A SIGNIFICANT DIFFERENCE IN TIMING OF HEAVY SNOW OR MIXED PRECIPITATION OVER THE REGION. TAKING THIS TIMING DIFFERENCE INTO ACCOUNT...THE 540 LINE IS LOCATED IN SIMILAR LOCATIONS...ENCOMPASSING ALL OF THE U.P. EXCLUDING KEWEENAW COUNTY AND POSSIBLY THE NORTHERN TIP OF LUCE COUNTY. WILL NEED TO KEEP THIS IN MIND AS WE FIGURE OUT THE TYPE OF PRECIPITATION POSSIBLE SATURDAY NIGHT AND SUNDAY. EITHER WAY...AFTER 03Z MONDAY...SNOW WILL DOMINATE UPPER MICHIGAN AS WINDS BECOMING NORTHWESTERLY WITH THE SURFACE LOW SLIDES EASTWARD INTO LAKE HURON AND EXTREME SOUTHEASTERN ONTARIO. WHEN COMPARING THE TRACK OF THIS SURFACE LOW WITH THE CAN/ECMWF/UKMET/GFS/NAM...THE NAM WAS INDEED MUCH SLOWER. AS A RESULT OF THIS AND THE FACT THAT IT WAS NOTED IN THE PREVIOUS DISCUSSION THAT IT WAS ONE OF THE FARTHER SE MODELS....WITH LIMITED RUN TO RUN CONSISTENCY...IT WAS DISCREDITED AND NOT USED IN THIS FORECAST PACKAGE BEYOND 00Z SUNDAY. AT 00Z MONDAY...THERE WERE GENERALLY 3 TRAINS OF THOUGHT...THE AFOREMENTIONED SLOW NAM...THE MORE NORTHERN AND CONSISTENTLY DEEPER UKMET/CANADIAN...AND THE QUICKER GFS/ECMWF. WILL HEDGE THE FORECAST TO THE GFS/ECMWF WITH SOME THOUGHT GIVEN TO THE BLEND OF THE CANADIAN/UKMET. SO...FORECAST WISE...WILL INCREASE TEMPERATURES SLIGHTLY FOR SUNDAY MORNING ON OUR STRENGTHENING SOUTHEASTERLY AND PLENTY OF CLOUD COVER. ELEVATED WARM LAYER ACROSS THE SOUTHERN HALF OF THE CWA MAY POSE A PROBLEM FOR MIXED PRECIPITATION...AS POCKET 0 TO -2C BETWEEN 700 AND 800MB SHOWS UP FROM 09Z-17Z SUNDAY AFTERNOON AT IMT WITH SFC TEMPS NEAR OR JUST ABOVE FREEZING. SO HAVE UTILIZED THE 750MB GFS TEMPS HEAVILY WHEN FIGURING OUT WEATHER FOR...SINCE THE SNOW GROWTH REGION IS BETWEEN 500 AND 600MB. EXPECT TEMPERATURES TO MAX OUT RIGHT AROUND 18Z...SO JUST SLIGHTLY BEFORE CLIMATOLOGICAL NORM. STILL...BY THIS TIME...MUCH OF THE ACCUMULATED SNOW WILL HAVE FALLEN. AS A RESULT...WARNINGS SEEM LIKELY. LOOKING AT MONDAY NIGHT/00Z TUESDAY THE 06Z GFS IS SLOWER THAN THE 00Z ECMWF TO PUSH THE 500MB CLOSED LOW EASTWARD TO THE NEW ENGLAND STATES...COMING MORE IN LINE WITH EACH OTHER BY 00Z WEDNESDAY FOR AT LEAST THE LOCATION OF THE 500MB LOW. HOWEVER...CLOSER TO HOME THE NEXT EMBEDDED TROUGH IN THIS LARGE SCALE FEATURE CAN BE EXPECTED TO SLIDE SOUTHWARD FROM NORTHERN ONTARIO TO NORTHERN LAKE SUPERIOR BY 00Z WEDNESDAY. THE 06Z GFS IS STRONGER/DEEPER WITH THIS NEXT SYSTEM. THE 06Z GFS...WITH ITS STRONGER TROUGH...KEEPS THE GENERAL TROUGHINESS OVER THE REGION THROUGH THURSDAY NIGHT INTO EARLY NEXT FRIDAY. ON THE OTHER HAND...WITH AN OVERALL WEAKER RENDITION...THE 00Z ECMWF WOULD ALLOW FOR SMALL SCALE RIDGING FOR A MAJORITY OF THE TIME FROM TUESDAY AFTERNOON ON. SO...THERE ARE SIGNIFICANT DIFFERENCES IN MODEL GUIDANCE OVER UPPER MICHIGAN. HPC GUIDANCE WAS HEAVILY UTILIZED...FOR DAYS 4/TUESDAY THROUGH 7/FRIDAY. THIS DID NOT INCLUDE THE 00Z CANADIAN...BUT WAS INSTEAD THE 00Z ECMWF EARLY IN THE PERIOD BEFORE A 50/50 BLEND OF THE 00Z ECMWF/NCEP ENSEMBLE MEAN FROM WEDNESDAY MORNING ONWARD...WITH PLENTY OF UNCERTAINTY IN THE LATER PART OF THE FORECAST PERIOD. WHAT IS MORE CERTAIN IS BELOW TO WELL BELOW AVG TEMPS WILL EXTEND FROM OUR REGION THROUGH THE SOUTHEASTERN UNITED STATES MIDWEEK. && .AVIATION (FOR THE 18Z TAF ISSUANCE)...AT CMX CONDITIONS WILL BEGIN TO IMPROVE BY LATE THIS EVENING...EXPECT MAINLY LIFR CONDITION UNTIL THEN. THIS IMPROVEMENT WILL BE THE RESULT OF A WEAKENING WIND FIELD AND A DIRECTION CHANGE TO OFFSHORE...AT THE SAME TIME CLOUD BASES WILL RISE AS LAKE EFFECT MECHANISMS WEAKEN ALONG WITH THE WIND. EXPECT VFR CONDITIONS BY EARLY SATURDAY MORNING THROUGH THE END OF THE TAF PERIOD. AT SAW...SOME LIGHT SNOW MAY OCCUR EARLY ON...MAINLY BEFORE 22Z. CLOUD DECKS WILL BE MVFR AT WORST...THOUGH THESE CONDITIONS SHOULD BE TEMPORARY IF THEY MANIFEST. AS THE WINDS BECOME MORE WESTERLY THIS EVENING...ANY LAKE EFFECT CLOUDS WILL AWAY FROM KSAW...LEAVING A SCATTERED DECK BEHIND. AT THE SAME TIME...A DECK OF HIGH CLOUDS WILL MOVE IN FROM THE SOUTHWEST...THOUGH THESE CLOUDS WILL BE VFR THROUGH THE TAF PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER EASTERN ONTARIO TO MOVE TO MAINE TONIGHT AS HIGH PRESSURE OVER THE CENTRAL PLAINS MOVES TO THE OHIO VALLEY AND GREAT LAKES. LINGERING WNW GALES THIS EVNG WILL DIMINISH BY MIDNGT AS THE WEAKER PRES GRADIENT ASSOCIATED WITH THE HIGH PUSHES EWD. THE HIGH WILL REACH WESTERN QUEBEC BY SATURDAY EVENING AS A LOW PRESSURE OF 29.2 INCHES OVER THE CENTRAL PLAINS SATURDAY EVENING REACHES LAKE MICHIGAN SUNDAY AFTERNOON. THERE WILL LIKELY BE ANOTHER ESE GALE SAT NGT INTO SUN AS THIS LOW GRINDS INTO HI PRES TO THE NE AND SHARPENS THE PRES GRADIENT OVER THE UPR LKS. THE LOW WILL THEN REACH THE EASTERN GREAT LAKES BY MONDAY MORNING AS ANOTHER HIGH PRESSURE RIDGE MOVES INTO THE PLAINS. ANOTHER N GALE EVENT IS LIKELY SUN NIGHT INTO MONDAY IN THE TIGHT PRES GRADIENT BETWEEN THESE FEATURES. THE RIDGE WILL THEN MOVE TO THE EASTERN GREAT LAKES WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM MAKES ITS WAY FROM ALBERTA TO SOUTHERN LAKE MICHIGAN. ATTM...EXPECT N WINDS TO 30 KTS AS THE PRES GRADIENT TIGHTENS OVER THE UPR LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING FROM 7 PM SATURDAY TO 1 PM EST SUNDAY FOR MIZ001-003>007-014-085. WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ001>003. WINTER STORM WARNING FROM 1 PM EST /12 PM CST/ SATURDAY TO 1 PM EST /12 PM CST/ SUNDAY FOR MIZ002-009>013-084. LAKE EFFECT SNOW ADVISORY UNTIL 3 AM EST SATURDAY FOR MIZ085. WINTER STORM WARNING UNTIL 5 AM EST SATURDAY FOR MIZ006-007. LAKE SUPERIOR...GALE WARNING UNTIL 9 PM EST THIS EVENING FOR LSZ249>251-265>267. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...DJP MARINE...KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1232 AM EST FRI NOV 30 2007 UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE .UPDATE (ISSUED AT 1029 PM EST)... SHIFTING LES IS THE MAIN FCST ISSUE OVERNIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DOMINATING CANADA AND THE NRN CONUS WITH A CLOSED LOW LOCATED JUST SW OF HUDSON BAY. ARCTIC AIR CONTINUES TO SPREAD SE INTO THE UPPER GREAT LAKES THIS EVENING. 00Z KINL SOUNDING SHOWED 850MB TEMP OF -25C...5C LWR THAN AT 12Z. FARTHER UPSTREAM...850MB TEMP AT CYQD N OF LAKE WINNIPEG WAS A FRIGID -29C. THIS WILL SET THE STAGE FOR A VERY COLD DAY FRI. IN THE MEANTIME...SHORTWAVE CURRENTLY ROTATING SE TOWARD THE UPPER MISSISSIPPI VALLEY IS CAUSING LOW-LEVEL WINDS TO BACK ACROSS UPPER MI WITH LAND BREEZES FURTHER BACKING WINDS TO A SW DIRECTION ALONG THE LAKE SUPERIOR SHORE. THIS SHIFTED LES BANDS QUICKLY OFFSHORE OF ALGER/LUCE COUNTIES THIS EVENING. TO THE NW...BANDS ARE ALSO SHIFTING N...AND IT APPEARS THERE MAY NOT BE MUCH SNOW FALLING S OF HOUGHTON NOW. ENHANCED LAND BREEZE CONVERGENCE FROM KDLH TOWARD THE APOSTLES IS LEADING TO A DOMINANT LES BAND STREAMING ENE TO THE KEWEENAW PER SATELLITE IMAGERY. THAT BAND APPEARS TO BE CROSSING KEWEENAW COUNTY ATTM. IN FACT...OBSERVER AT MOHAWK REPORTED 2.5 INCHES OF SNOW BTWN 01-02Z WITH 4 INCHES TOTAL FROM 01Z-0315Z. AS SHORTWAVE PASSES...LOW-LEVEL WINDS WILL VEER TO A MORE NWRLY DIRECTION ACROSS MOST OF LAKE SUPERIOR OVERNIGHT WHICH WILL IN TURN SHIFT LES BACK TO THE S. 00Z RUC AND LOCALLY RUN HIGH RES WRF-ARW INDICATE CONVERGENCE BAND WILL ALREADY BEGIN SHIFTING BACK S ACROSS THE KEWEENAW SOMETIME BTWN 04-06Z AND WILL REACH NRN ONTONAGON COUNTY BTWN 09-12Z. IT MAY NOT BE UNTIL AROUND 12Z THAT THE CONVERGENCE BAND WILL REACH THE ERN FCST AREA FROM GRAND MARAIS EWD. HAVE ALREADY MADE ADJUSTMENTS EARLIER IN THE EVENING TO REMOVE SHSN S OF THE CONVERGENCE ZONE DUE TO NO OVERWATER FETCH WITH A SW WIND. HAVE MADE FURTHER ADJUSTMENTS FOR THE OVERNIGHT TO DELAY REINTRODUCTION OF SHSN AS CONVERGENCE ZONE SLOWLY SHIFTS S. AS FOR THE WINTER STORM WARNING OVER THE NW COUNTIES...SNOW ACCUMULATIONS WILL BE WEIGHED HEAVILY ON MOVEMENT OF THE DOMINANT HVY SNOW BAND NOW OVER KEWEENAW COUNTY. SNOW ACCUMULATIONS OF 2-3IN/HR WILL OCCUR AS THIS BAND SLOWLY SHIFTS S. ONCE BAND STARTS MOVING S...WOULD EXPECT SUFFICIENT MOVEMENT FOR IT NOT TO LINGER MORE THAN A COUPLE OF HRS AT ANY LOCATION. SO...BTWN NOW AND 12Z...A GENERAL 4-6 INCHES OF NEW SNOW SHOULD FALL FROM AROUND MOHAWK S TO NEAR ROCKLAND. MIGHT SEE SOME LOCALLY HIGHER AMOUNTS. && .SHORT TERM (TONIGHT AND FRIDAY)... WIND DIRECTION WILL REMAIN FAVORABLE FOR LAKE EFFECT SNOW ACROSS THE EXTREME EASTERN PORTIONS OF THE CWA OVER THE NEXT FEW HOURS BEFORE BECOMING MORE WESTERLY ONCE AGAIN...TURNING OFF MUCH OF THE SNOW SHOWERS. AS A RESULT...WILL KEEP THE LAKE EFFECT SNOW ADVISORY POSTED FOR THIS AREA UNTIL ITS GIVEN EXPIRATION TIME. OTHERWISE...FARTHER TO THE WEST...NORTHWESTERLY WINDS TO WESTERLY WINDS STILL REMAIN FAVORABLE FOR ADDITIONAL SNOW FOR THE KEWEENAW PENINSULA. WILL KEEP THE LAKE EFFECT SNOW WARNING THERE WITH NO CHANGES IN TIME. AS THE SURFACE LOW JUST SOUTHEAST OF HUDSON BAY CONTINUES TO SLIDE NORTHEASTWARD AWAY FROM THE AREA...WINDS WILL WEAKEN. A SECONDARY TROUGH OVER NORTHERN AND WESTERN MINNESOTA WILL SLIDE OVER THE WESTERN UPPER MICHIGAN EARLY THIS EVENING...AND RESIDE OVER THE FAR EASTERN U.P. BY 12Z FRIDAY. THIS WILL HELP TO BRING ABOUT NORTHWESTERLY WINDS ONCE AGAIN OVER THE REGION BY 16Z FRIDAY...WITH A LIKELY LAKE EFFECT SNOW SHOWERS CONTINUING INTO THE AFTERNOON HOURS OVER THE FAR EAST AND NORTHWESTERN SECTIONS OF THE CWA. THE 500MB CLOSED LOW WILL SKIM NORTHERN LAKE SUPERIOR LATE FRIDAY MORNING. HIGH PRESSURE WILL THEN BUILD IN AT THE SURFACE AND ALOFT...AHEAD OF THE NEXT LOW GAINING STEAM OVER THE BAJA PENINSULA FRIDAY EVENING. THE MAIN CHANGES TO THIS FORECAST PACKAGE INCLUDED LOWERING POPS AND SKY COVER ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA...AS WELL AS LOWERING OVERNIGHT TEMPERATURES SLIGHTLY. .LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... MAIN FCST CONCERNS SHIFT FROM LES TO IMPACTS OF THE STORM SYSTEM MOVING INTO THE REGION THIS WEEKEND. FRI NIGHT...A SFC RIDGE WILL MOVE THROUGH THE WESTERN GREAT LAKES BRINGING A TEMPORARY END TO THE LAKE EFFECT SNOW BY SATURDAY MORNING. WNW CBL WINDS WITH 850 MB TEMPS STILL NEAR -20C WILL KEEP LES GOING OVER THE WEST AND FOR LOCATIONS FROM MUNISING EASTWARD. THE 12Z LCL HIGH RES WRF/ARW AND THE NAM SUGGEST POTENTIAL FOR ENHANCED LOW LEVEL CONV AGAIN NEAR ONTONAGON AND M-38 OVERNIGHT AS THE WINDS BEGIN TO BACK AND WEAKEN. SIMILARLY...IN THE EAST A WEAKER WIND FIELD WILL ALLOW LAKE INDUCED TROFFING TO DEVELOP WITH POTENTIAL FOR BRIEF HEAVIER SNOWFALL RATES IF A MESO-LOW LIKE FEATURE BRUSHES THE SHORELINE. FCST INCLUDES LES ACCUMULATION RANGE OF 1 TO 4 INCHES GIVEN UNCERTAINTY WITH SHIFTING LES BAND(S) POSITION IN WEAKER WIND REGIME. SAT INTO SUN...THE 12Z GLOBAL MODELS WERE IN REASONABLE AGREEMENT WITH THE EVOLUTION OF THE MID LEVEL TROUGH AND PATH OF THE SURFACE LOW MOVING OUT OF THE PLAINS. THE PREFERRED 12Z GFS/ECMWF/UKMET CONSENSUS BRINGS THE LOW TO NEAR CENTRAL WI BY 12Z/SUN AND TO THE N END OF LK HURON BY 00Z/MON. THE CANADIAN GLBL GEM CONTINUED TO DEPICT A MORE WESTWARD PATH TOWARD WEST UPPER MI BY 12Z/SUN. STRONG MID/UPPER LEVEL SUPPORT WILL FEATURE COUPLED 300 MB JET STRUCTURE WITH STRONG 700-500 QVECTOR CONV AND ISENTROPIC ASCENT OVER THE REGION. GFS FCST SOUNDINGS (WARM LAYER TO NEAR 2C BTWN 800-750 MB) AND GFS/ECMWF/UKMET 850-700 THICKNESS PROGS(INTO THE 1545-1560M RANGE) SUGGEST POTENTIAL FOR SOME SLEET INTO SRN UPPER MI. SINCE THE GFS OFTEN UNDERPLAYS ELEVATED WARM LAYER...A MENTION OF FZRA WAS ALSO INCLUDED SOUTH. AN INFLUX OF WARMER AIR ESPECIALLY NEAR LAKE MI WHERE ESE WINDS ARE EXPECTED COULD ALSO BRING A CHANGEOVER TO RAIN. DRYING ABOVE 750 MB COULD ALSO BRING A PERIOD OF FZDZ SUN MORNING. AMPLE GULF MOISTURE WILL BE AVAILABLE WITH NEARLY 4-5 G/KG JUST UPSTREAM ON 295K SFC. MODELS QPF AMOUNTS OF ABOUT 0.75 TO 1.00 INCH FROM LATE SAT INTO MIDDAY SUN WITH SNOWFALL/RATIO NEAR 10/1 WOULD BRING SNOW TOTALS OF 6-10 INCHES. THE PATTERN DOES NOT FAVOR AN EXTENDED PERIOD OF LAKE ENHANCED SNOW OFF OF LAKE SUPERIOR WITH MAINLY WAA PCPN WITH A TRANSITION TO MAINLY PURE LAKE EFFECT SNOW AS WINDS SHIFT TO THE NNW LATE SUN AND STRONGER CAA MOVES IN. WITH REMAINING UNCERTAINTY ON STORM PATH AND IMPACT ON PCPN TYPE AND TIMING OF PCPN INTO LATE DAY 2...HELD OFF ON WATCH FOR NOW BUT WILL ISSUE AN SPS TO HIGHLIGHT THE POTENTIAL HAZARDS. SUN NIGHT INTO MON...STRONG CAA PUSHING 850 MB TEMPS DOWN TO -18C WILL BRING ANOTHER ROUND OF MODERATE TO HEAVY LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY NNW TO NW FLOW. TUE-THU...THE ECMWF TRENDED NORTHWARD AND HAS COME INTO BETTER AGREEMENT WITH THE POSSIBILITY OF CLIPPER MOVING THROUGH LATE TUE INTO TUE NIGHT. CONFIDENCE IN THE DETAILS IS STILL LOW...BUT WITH COLDER REMAINING ENTRENCHED OVER THE REGION...THE SHORTWAVE COULD ALSO BRING PERIOD OF LAKE ENHANCED SNOW FOLLOWED BY ADDITIONAL LES IN ITS WAKE. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... AT KSAW...UNDER CURRENT LAKE EFFECT REGIME...GENERAL WRLY FLOW SHOULD MAINTAIN VFR CONDITIONS FOR THIS FCST PERIOD. WINDS WILL VEER SLIGHTLY FRI MORNING WHICH SHOULD RESULT IN MORE CLOUDS AND POSSIBLY SOME FLURRIES. THERE MIGHT BE A BRIEF PERIOD OF HIGH END MVFR CIGS A FEW HRS EITHER SIDE OF SUNRISE...BUT CONFIDENCE IS TOO LOW TO INCLUDE ATTM. KCMX WILL CONTINUE TO BE HAMMERED BY LAKE EFFECT SHSN AND BLSN...ESPECIALLY OVERNIGHT/FRI MORNING. CONVERGENT WINDS OVER WRN LAKE SUPERIOR HAVE PRODUCED A SINGLE INTENSE LAKE EFFECT SNOW BAND WHICH IS CURRENTLY IMPACTING THE KEWEENAW N OF KCMX. AS WINDS VEER OVER THE NEXT FEW HRS...THIS INTENSE SNOW BAND WILL SHIFT S TO KCMX...RESULTING IN VLIFR VIS OF 1/4SM IN +SHSN. AFTER THE SNOW BAND SINKS S OF KCMX...STRONG W WINDS WILL AGAIN TAKE OVER WITH CONSIDERABLE BLSN IN ADDITION TO PERSISTENT SHSN/-SHSN. VLIFR VIS IN -SHSN/BLSN WILL LIKELY PERSIST UNTIL MID TO LATE MORNING. APPROACHING HIGH PRES FRI AFTN SHOULD SUPPORT GRADUAL IMPROVING CONDITIONS. HOWEVER...PERSISTENT -SHSN MAY KEEP VIS IN THE IFR RANGE THRU THE END OF THIS FCST PERIOD. WINDS WILL DROP SIGNIFICANTLY IN THE EVENING...BRINGING AN END TO BLSN. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... GALES OF 40 TO 45 KNOTS HAVE BEEN REALIZED ACROSS PORTIONS OF THE EASTERN HALF OF LAKE SUPERIOR. THESE WINDS WILL CONTINUE TO SLOWLY DIMINISH AS THE SURFACE LOW SLIDES NORTHEASTWARD OUT OF THE REGION. ANOTHER TROUGH WILL SLIDE ACROSS LAKE SUPERIOR LATE TONIGHT THROUGH MID MORNING FRIDAY. STILL...WINDS WILL REMAIN IN THE 20 TO 25 KNOT RANGE THROUGH FRIDAY...WITH SOME GUSTS TO 35 KNOTS POSSIBLE. BRIEF HIGH PRESSURE WILL ALLOW WINDS TO DROP BELOW 30 KNOTS. FOLLOWING THAT WILL BE THE APPROACHING SURFACE LOW FROM THE COLORADO ROCKIES OVER THE WEEKEND...WITH GALES EXPECTED ONCE AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN... WINTER STORM WARNING UNTIL 7 PM EST FRI MIZ001>003. LAKE SUPERIOR... GALE WARNING UNTIL 5 AM EST FRI LSZ266-267. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SHORT TERM...KF LONG TERM...JLB AVIATION...ROLFSON MARINE...KF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1029 PM EST THU NOV 29 2007 .UPDATE... SHIFTING LES IS THE MAIN FCST ISSUE OVERNIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DOMINATING CANADA AND THE NRN CONUS WITH A CLOSED LOW LOCATED JUST SW OF HUDSON BAY. ARCTIC AIR CONTINUES TO SPREAD SE INTO THE UPPER GREAT LAKES THIS EVENING. 00Z KINL SOUNDING SHOWED 850MB TEMP OF -25C...5C LWR THAN AT 12Z. FARTHER UPSTREAM...850MB TEMP AT CYQD N OF LAKE WINNIPEG WAS A FRIGID -29C. THIS WILL SET THE STAGE FOR A VERY COLD DAY FRI. IN THE MEANTIME...SHORTWAVE CURRENTLY ROTATING SE TOWARD THE UPPER MISSISSIPPI VALLEY IS CAUSING LOW-LEVEL WINDS TO BACK ACROSS UPPER MI WITH LAND BREEZES FURTHER BACKING WINDS TO A SW DIRECTION ALONG THE LAKE SUPERIOR SHORE. THIS SHIFTED LES BANDS QUICKLY OFFSHORE OF ALGER/LUCE COUNTIES THIS EVENING. TO THE NW...BANDS ARE ALSO SHIFTING N...AND IT APPEARS THERE MAY NOT BE MUCH SNOW FALLING S OF HOUGHTON NOW. ENHANCED LAND BREEZE CONVERGENCE FROM KDLH TOWARD THE APOSTLES IS LEADING TO A DOMINANT LES BAND STREAMING ENE TO THE KEWEENAW PER SATELLITE IMAGERY. THAT BAND APPEARS TO BE CROSSING KEWEENAW COUNTY ATTM. IN FACT...OBSERVER AT MOHAWK REPORTED 2.5 INCHES OF SNOW BTWN 01-02Z WITH 4 INCHES TOTAL FROM 01Z-0315Z. AS SHORTWAVE PASSES...LOW-LEVEL WINDS WILL VEER TO A MORE NWRLY DIRECTION ACROSS MOST OF LAKE SUPERIOR OVERNIGHT WHICH WILL IN TURN SHIFT LES BACK TO THE S. 00Z RUC AND LOCALLY RUN HIGH RES WRF-ARW INDICATE CONVERGENCE BAND WILL ALREADY BEGIN SHIFTING BACK S ACROSS THE KEWEENAW SOMETIME BTWN 04-06Z AND WILL REACH NRN ONTONAGON COUNTY BTWN 09-12Z. IT MAY NOT BE UNTIL AROUND 12Z THAT THE CONVERGENCE BAND WILL REACH THE ERN FCST AREA FROM GRAND MARAIS EWD. HAVE ALREADY MADE ADJUSTMENTS EARLIER IN THE EVENING TO REMOVE SHSN S OF THE CONVERGENCE ZONE DUE TO NO OVERWATER FETCH WITH A SW WIND. HAVE MADE FURTHER ADJUSTMENTS FOR THE OVERNIGHT TO DELAY REINTRODUCTION OF SHSN AS CONVERGENCE ZONE SLOWLY SHIFTS S. AS FOR THE WINTER STORM WARNING OVER THE NW COUNTIES...SNOW ACCUMULATIONS WILL BE WEIGHED HEAVILY ON MOVEMENT OF THE DOMINANT HVY SNOW BAND NOW OVER KEWEENAW COUNTY. SNOW ACCUMULATIONS OF 2-3IN/HR WILL OCCUR AS THIS BAND SLOWLY SHIFTS S. ONCE BAND STARTS MOVING S...WOULD EXPECT SUFFICIENT MOVEMENT FOR IT NOT TO LINGER MORE THAN A COUPLE OF HRS AT ANY LOCATION. SO...BTWN NOW AND 12Z...A GENERAL 4-6 INCHES OF NEW SNOW SHOULD FALL FROM AROUND MOHAWK S TO NEAR ROCKLAND. MIGHT SEE SOME LOCALLY HIGHER AMOUNTS. && .PREV DISCUSSION (ISSUED AT 425 PM EST)... SHORT TERM (TONIGHT AND FRIDAY... WIND DIRECTION WILL REMAIN FAVORABLE FOR LAKE EFFECT SNOW ACROSS THE EXTREME EASTERN PORTIONS OF THE CWA OVER THE NEXT FEW HOURS BEFORE BECOMING MORE WESTERLY ONCE AGAIN...TURNING OFF MUCH OF THE SNOW SHOWERS. AS A RESULT...WILL KEEP THE LAKE EFFECT SNOW ADVISORY POSTED FOR THIS AREA UNTIL ITS GIVEN EXPIRATION TIME. OTHERWISE...FARTHER TO THE WEST...NORTHWESTERLY WINDS TO WESTERLY WINDS STILL REMAIN FAVORABLE FOR ADDITIONAL SNOW FOR THE KEWEENAW PENINSULA. WILL KEEP THE LAKE EFFECT SNOW WARNING THERE WITH NO CHANGES IN TIME. AS THE SURFACE LOW JUST SOUTHEAST OF HUDSON BAY CONTINUES TO SLIDE NORTHEASTWARD AWAY FROM THE AREA...WINDS WILL WEAKEN. A SECONDARY TROUGH OVER NORTHERN AND WESTERN MINNESOTA WILL SLIDE OVER THE WESTERN UPPER MICHIGAN EARLY THIS EVENING...AND RESIDE OVER THE FAR EASTERN U.P. BY 12Z FRIDAY. THIS WILL HELP TO BRING ABOUT NORTHWESTERLY WINDS ONCE AGAIN OVER THE REGION BY 16Z FRIDAY...WITH A LIKELY LAKE EFFECT SNOW SHOWERS CONTINUING INTO THE AFTERNOON HOURS OVER THE FAR EAST AND NORTHWESTERN SECTIONS OF THE CWA. THE 500MB CLOSED LOW WILL SKIM NORTHERN LAKE SUPERIOR LATE FRIDAY MORNING. HIGH PRESSURE WILL THEN BUILD IN AT THE SURFACE AND ALOFT...AHEAD OF THE NEXT LOW GAINING STEAM OVER THE BAJA PENINSULA FRIDAY EVENING. THE MAIN CHANGES TO THIS FORECAST PACKAGE INCLUDED LOWERING POPS AND SKY COVER ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA...AS WELL AS LOWERING OVERNIGHT TEMPERATURES SLIGHTLY. LONG TERM (FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 425 PM EST)... MAIN FCST CONCERNS SHIFT FROM LES TO IMPACTS OF THE STORM SYSTEM MOVING INTO THE REGION THIS WEEKEND. FRI NIGHT...A SFC RIDGE WILL MOVE THROUGH THE WESTERN GREAT LAKES BRINGING A TEMPORARY END TO THE LAKE EFFECT SNOW BY SATURDAY MORNING. WNW CBL WINDS WITH 850 MB TEMPS STILL NEAR -20C WILL KEEP LES GOING OVER THE WEST AND FOR LOCATIONS FROM MUNISING EASTWARD. THE 12Z LCL HIGH RES WRF/ARW AND THE NAM SUGGEST POTENTIAL FOR ENHANCED LOW LEVEL CONV AGAIN NEAR ONTONAGON AND M-38 OVERNIGHT AS THE WINDS BEGIN TO BACK AND WEAKEN. SIMILARLY...IN THE EAST A WEAKER WIND FIELD WILL ALLOW LAKE INDUCED TROFFING TO DEVELOP WITH POTENTIAL FOR BRIEF HEAVIER SNOWFALL RATES IF A MESO-LOW LIKE FEATURE BRUSHES THE SHORELINE. FCST INCLUDES LES ACCUMULATION RANGE OF 1 TO 4 INCHES GIVEN UNCERTAINTY WITH SHIFTING LES BAND(S) POSITION IN WEAKER WIND REGIME. SAT INTO SUN...THE 12Z GLOBAL MODELS WERE IN REASONABLE AGREEMENT WITH THE EVOLUTION OF THE MID LEVEL TROUGH AND PATH OF THE SURFACE LOW MOVING OUT OF THE PLAINS. THE PREFERRED 12Z GFS/ECMWF/UKMET CONSENSUS BRINGS THE LOW TO NEAR CENTRAL WI BY 12Z/SUN AND TO THE N END OF LK HURON BY 00Z/MON. THE CANADIAN GLBL GEM CONTINUED TO DEPICT A MORE WESTWARD PATH TOWARD WEST UPPER MI BY 12Z/SUN. STRONG MID/UPPER LEVEL SUPPORT WILL FEATURE COUPLED 300 MB JET STRUCTURE WITH STRONG 700-500 QVECTOR CONV AND ISENTROPIC ASCENT OVER THE REGION. GFS FCST SOUNDINGS (WARM LAYER TO NEAR 2C BTWN 800-750 MB) AND GFS/ECMWF/UKMET 850-700 THICKNESS PROGS(INTO THE 1545-1560M RANGE) SUGGEST POTENTIAL FOR SOME SLEET INTO SRN UPPER MI. SINCE THE GFS OFTEN UNDERPLAYS ELEVATED WARM LAYER...A MENTION OF FZRA WAS ALSO INCLUDED SOUTH. AN INFLUX OF WARMER AIR ESPECIALLY NEAR LAKE MI WHERE ESE WINDS ARE EXPECTED COULD ALSO BRING A CHANGEOVER TO RAIN. DRYING ABOVE 750 MB COULD ALSO BRING A PERIOD OF FZDZ SUN MORNING. AMPLE GULF MOISTURE WILL BE AVAILABLE WITH NEARLY 4-5 G/KG JUST UPSTREAM ON 295K SFC. MODELS QPF AMOUNTS OF ABOUT 0.75 TO 1.00 INCH FROM LATE SAT INTO MIDDAY SUN WITH SNOWFALL/RATIO NEAR 10/1 WOULD BRING SNOW TOTALS OF 6-10 INCHES. THE PATTERN DOES NOT FAVOR AN EXTENDED PERIOD OF LAKE ENHANCED SNOW OFF OF LAKE SUPERIOR WITH MAINLY WAA PCPN WITH A TRANSITION TO MAINLY PURE LAKE EFFECT SNOW AS WINDS SHIFT TO THE NNW LATE SUN AND STRONGER CAA MOVES IN. WITH REMAINING UNCERTAINTY ON STORM PATH AND IMPACT ON PCPN TYPE AND TIMING OF PCPN INTO LATE DAY 2...HELD OFF ON WATCH FOR NOW BUT WILL ISSUE AN SPS TO HIGHLIGHT THE POTENTIAL HAZARDS. SUN NIGHT INTO MON...STRONG CAA PUSHING 850 MB TEMPS DOWN TO -18C WILL BRING ANOTHER ROUND OF MODERATE TO HEAVY LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY NNW TO NW FLOW. TUE-THU...THE ECMWF TRENDED NORTHWARD AND HAS COME INTO BETTER AGREEMENT WITH THE POSSIBILITY OF CLIPPER MOVING THROUGH LATE TUE INTO TUE NIGHT. CONFIDENCE IN THE DETAILS IS STILL LOW...BUT WITH COLDER REMAINING ENTRENCHED OVER THE REGION...THE SHORTWAVE COULD ALSO BRING PERIOD OF LAKE ENHANCED SNOW FOLLOWED BY ADDITIONAL LES IN ITS WAKE. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KSAW...UNDER CURRENT LAKE EFFECT REGIME...GENERAL WRLY FLOW WILL MAINTAIN VFR CONDITIONS FOR THIS FCST PERIOD. WINDS WILL VEER SLIGHTLY FRI MORNING WHICH SHOULD RESULT IN MORE CLOUDS AND POSSIBLY SOME FLURRIES. KCMX WILL CONTINUE TO BE HAMMERED BY LAKE EFFECT SHSN AND BLSN...ESPECIALLY TONIGHT/FRI MORNING...AS EVEN COLDER AIR SPREADS OVER THE UPPER GREAT LAKES. DON`T SEE MUCH REASON TO BE OPTIMISTIC FOR VIS TO IMPROVE OUT OF THE VLIFR/LIFR RANGE THRU FRI MORNING DUE TO THE COMBINATION OF SHSN/BLSN. THERE MAY BE SOME IMPROVEMENT FRI AFTN AS HIGH PRES BEGINS TO BUILD INTO THE WRN GREAT LAKES. EVEN SO...MAY NOT SEE IMPROVEMENT ABOVE IFR CONDITIONS. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... GALES OF 40 TO 45 KNOTS HAVE BEEN REALIZED ACROSS PORTIONS OF THE EASTERN HALF OF LAKE SUPERIOR. THESE WINDS WILL CONTINUE TO SLOWLY DIMINISH AS THE SURFACE LOW SLIDES NORTHEASTWARD OUT OF THE REGION. ANOTHER TROUGH WILL SLIDE ACROSS LAKE SUPERIOR LATE TONIGHT THROUGH MID MORNING FRIDAY. STILL...WINDS WILL REMAIN IN THE 20 TO 25 KNOT RANGE THROUGH FRIDAY...WITH SOME GUSTS TO 35 KNOTS POSSIBLE. BRIEF HIGH PRESSURE WILL ALLOW WINDS TO DROP BELOW 30 KNOTS. FOLLOWING THAT WILL BE THE APPROACHING SURFACE LOW FROM THE COLORADO ROCKIES OVER THE WEEKEND...WITH GALES EXPECTED ONCE AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN... WINTER STORM WARNING UNTIL 7 PM EST FRI MIZ001>003. LAKE SUPERIOR... GALE WARNING UNTIL 5 AM EST FRI LSZ266-267. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SHORT TERM...KF LONG TERM...JLB AVIATION...ROLFSON MARINE...KF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1220 PM EST THU NOV 29 2007 UPDATED AVIATION SECTION FOR 18Z TAF ISSUANCE .DISCUSSION... MAIN FORECAST CONCERNS ARE PERSISTENT LES ALONG LAKE SUPERIOR SHORELINE AND NECESSARY HEADLINES. IR IMAGERY AND RUC ANALYSIS SHOW A LARGE UPPER LEVEL RIDGE ACROSS THE EASTERN UNITED STATES...AND TWO SHORTWAVES EMBEDDED IN A LARGE SCALE TROUGH PASSING ACROSS LAKE SUPERIOR. TWO UPPER LEVEL LOWS ARE NEARLY STATIONARY NEAR THE ALEUTIAN ISLANDS AND OFF BAJA CALIFORNIA. AT THE SURFACE...THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THE SNOW ACROSS THE CWA ON WEDNESDAY CONTINUES TO MOVE EAST THROUGH ONTARIO...WHILE HIGH PRESSURE SITS OVER THE ROCKIES. LAKE EFFECT SNOW REMAINS THE MAIN PLAYER IN THE FORECAST...WITH THE MAIN DIFFICULTIES INCLUDING THE MOVEMENT OF BANDS DUE TO MINOR WIND DIRECTION CHANGES AND WHETHER ACCUMULATIONS WILL WARRANT ADDITIONAL HEADLINES. ALL MODELS AGREE ON WESTERLY COMPONENT TO LOW LEVEL FLOW AND MOIST LOW LEVELS...WITH STRONG CONVERGENCE ALONG LAKE SUPERIOR SHORELINE. 850MB TEMPS WILL NOT BE AN ISSUE AS THEY RANGE FROM -13 TO -20C WITH LAKE TEMPERATURES AROUND 4C...GENERATING LOW LEVEL CAPE. A SPOTTER FROM ROCKLAND REPORTED 3.7 INCHES OF SNOW FROM 11 PM TO 230 AM...WITH THE HOUGHTON POLICE REPORTING 3 TO 4 INCHES OF SNOW FROM 7 PM THROUGH 245 AM AND LOTS OF BLOWING SNOW. KMQT RADAR IS RECEIVING RADAR RETURNS FROM A SNOW BAND ACROSS THE TWIN LAKES AREA AND A SECOND BAND OVER HOUGHTON. CONSIDERING THE TYPICAL BEAM BLOCKAGE THAT OCCURS WITH LAKE EFFECT SNOW IN THESE AREAS...THIS IS A STRONG SIGNAL THAT BANDS ARE QUITE DEVELOPED IF RETURNS ARE NOTED AT 9000 FEET. IN ADDITION...WITH SLIGHTLY HIGHER QPF FORECASTED...DECIDED TO ISSUE A WARNING FOR MUCH OF THE NORTHWEST. THE COMBINATION OF HEAVY SNOW AND WIND GUSTS TO 30 MPH PROMPTED A WINTER STORM WARNING INSTEAD OF A LAKE EFFECT SNOW WARNING DUE TO THE ADDITIONAL HAZARD OF BLOWING SNOW AND OCCASIONAL WHITEOUT CONDITIONS. WILL CONTINUE THE LAKE EFFECT SNOW ADVISORY FOR SOUTHERN HOUGHTON COUNTY...AS CONVERGENCE IS NOT AS STRONG THERE AND SNOWFALL TOTALS SHOULD NOT BE AS HIGH. CONVERGENCE SHOULD NOT BE QUITE AS HIGH DURING THE AFTERNOON HOURS IN THE WARNED COUNTIES AS DURING THE MORNING...AND THEREFORE SNOW ACCUMULATIONS SHOULD BE SLIGHTLY LESS DURING THAT TIME PERIOD. THE EASTERN LAKESHORE WILL HAVE ITS OWN SHARE OF SNOWFALL. CONVERGENCE ALSO LOOKS RATHER FAVORABLE ALONG THE PICTURED ROCKS SHORELINE. A LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY WAS ISSUED FOR ALGER AND LUCE COUNTIES DUE TO THE SNOW THAT WILL FALL ALONG THE IMMEDIATE COAST. WHILE MODELS INDICATE THAT STRONG BANDING SNOW SHOULD OCCUR...THE ONE CONCERN IS THAT IF WINDS PICK UP ANY SOUTHERLY COMPONENT...THESE BANDS MAY OCCUR OVER WATER INSTEAD OF OVER LAND. THEN AGAIN...IF WINDS BECOME MORE NORTHWESTERLY...THERE IS THE POSSIBILITY OF A BAND PARKING ITSELF ALONG THE SHORELINE AND CAUSING WARNING-CRITERIA SNOWFALL. TONIGHT...WINDS BECOME SOUTHWESTERLY...SHUTTING OFF LAKE EFFECT OUT EAST. ALONG THE WESTERN SHORELINE...LES WILL ONLY BE ENHANCED AS A SHORTWAVE MOVES IN FROM THE WEST AND ADDS A SYNOPTIC LIFTING MECHANISM. INVERSION HEIGHTS WILL RISE BACK ABOVE 5000 FT AND SNOWFALL RATES SHOULD RAMP UP. SIMILAR TO THE ISSUES OUT EAST TODAY...THE WIND DIRECTION WILL BE A MAJOR FACTOR IN EXACTLY WHERE BANDS DEVELOP AND DROP THE GREATEST AMOUNT OF SNOW. IF WINDS PICK ONE DIRECTION AND STAY AT THAT DIRECTION...SNOWFALL TOTALS SHOULD BE RATHER HIGH IN THAT LOCATION. FRIDAY NIGHT...LES SHOULD RETURN OUT EAST AS WINDS BECOME NORTHWESTERLY AGAIN AND MOIST AIR RETURNS TO THE AREA. SNOW WILL CONTINUE ACROSS THE WESTERN LAKESHORE...ALTHOUGH RATES SHOULD BE DROPPING BY THIS TIME. BY LATE SATURDAY THE NEXT SYNOPTIC SYSTEM BEGINS TO AFFECT THE AREA. MODEL RUNS CONTINUE TO BRING THE STORM SLIGHTLY FARTHER NORTH...AND THEREFORE INCREASED POPS THROUGH THE PERIOD. INTRODUCED A SLIGHT CHANCE OF SNOW ALONG THE WISCONSIN BORDER SATURDAY MORNING...WITH THE ENTIRE AREA HAVING CHANCE POPS SATURDAY NIGHT INTO MONDAY. RECENT MODEL RUNS ARE ALSO SHOWING THAT LOW LEVEL THICKNESSES MAY ALLOW FOR A MIX OF RAIN AND SNOW ALONG THE LAKE MICHIGAN SHORELINE ON SUNDAY AFTERNOON BEFORE CHANGING BACK OVER TO ALL SNOW. ONCE THE SYSTEM MOVES OFF TO THE EAST...STRONG N-NW FLOW SHOULD REMAIN OVER THE LAKE...BRINGING THE CHANCE FOR LAKE ENHANCED/EFFECT SNOW INTO MONDAY. NO CHANGES MADE TO THE FORECAST AFTER 00Z MONDAY. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT MUCH DIFFERENT CONDITIONS AT CMX WHEN COMPARED TO SAW. CMX...UNDER LAKE EFFECT SNOW THANKS TO WESTERLY WINDS...WILL REMAIN LIFR OR IFR THROUGH THE PERIOD. THE SHIFTS IN WINDS WILL MANDATE VIS AND CIGS AS WELL AS SNOW. SOME IMPROVEMENT IS FIGURED MAINLY AFTER 15Z FRIDAY...AS INVERSION HEIGHTS BEGIN TO LOWER BEHIND THE NEXT SHORTWAVE. AS FOR SAW...EVEN THOUGH WINDS WILL REMAIN SIMILAR OR JUST SLIGHTLY WEAKER THAN CMX...CEIGS AND VIS SHOULD REMAIN VFR. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WESTERLY GALES OF 35-40 KT WITH SLIGHTLY HIGHER GUSTS CONTINUE THIS MORNING ON LAKE SUPERIOR IN THE WAKE OF LOW PRESSURE LIFTING NORTHEAST FROM NEAR WAWA ONTARIO. THESE WINDS WILL GRADUALLY DIMINISH TODAY AS THE LOW MOVES FARTHER AWAY. HOWEVER...A TROUGH OF LOW PRESSURE CURRENTLY IN CENTRAL MANITOBA IS EXPECTED TO DROP SOUTH ACROSS LAKE SUPERIOR TONIGHT. WESTERLY WINDS WILL INCREASE AHEAD OF THIS LOW...PERHAPS REACHING GALES OVER THE SOUTHERN PORTION OF EASTERN LAKE SUPERIOR. IN THE WAKE OF THE TROUGH FRI MORNING...NW GALES ARE LIKELY...ESPECIALLY ON EASTERN LAKE SUPERIOR. HIGH PRESSURE WILL MOVE INTO THE AREA ON FRI NIGHT...ALLOWING WINDS TO FALL BELOW 20 KNOTS. HOWEVER...THIS HIGH IS EXPECTED TO QUICKLY MOVE EAST AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS. AS THIS FAIRLY DEEP LOW LIFTS TOWARDS THE AREA ON SAT NIGHT...SE WINDS WILL INCREASE TO GALES OVER THE EAST HALF OF LAKE SUPERIOR. THEN ON SUNDAY...THE LOW IS PROGGED TO MOVE ACROSS NORTHERN LAKE MICHIGAN...WHICH SHOULD LOWER THE WINDS BACK BELOW GALES...BRIEFLY. EXPECT NORTH TO NORTHWEST WINDS IN THE WAKE OF THE LOW SUNDAY NIGHT TO INCREASE BACK UP TO GALES...THEN DIMINISH ON MONDAY AS THE LOW MOVES TO NEW ENGLAND. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ001>003. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-007. LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ084. LAKE SUPERIOR...GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING FROM 2 AM TO 12 PM EST FRIDAY FOR LSZ266-267. GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ265. GALE WARNING FROM 3 AM TO 11 AM EST FRIDAY FOR LSZ265. GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ249>251-264. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ162-263. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ240>244. LAKE MICHIGAN...NONE. && $$ DISCUSSION...TAG AVIATION...AJ MARINE...KF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 706 AM EST THU NOV 29 2007 UPDATED AVIATION SECTION FOR 12Z TAF ISSUANCE .DISCUSSION... MAIN FORECAST CONCERNS ARE PERSISTENT LES ALONG LAKE SUPERIOR SHORELINE AND NECESSARY HEADLINES. IR IMAGERY AND RUC ANALYSIS SHOW A LARGE UPPER LEVEL RIDGE ACROSS THE EASTERN UNITED STATES...AND TWO SHORTWAVES EMBEDDED IN A LARGE SCALE TROUGH PASSING ACROSS LAKE SUPERIOR. TWO UPPER LEVEL LOWS ARE NEARLY STATIONARY NEAR THE ALEUTIAN ISLANDS AND OFF BAJA CALIFORNIA. AT THE SURFACE...THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THE SNOW ACROSS THE CWA ON WEDNESDAY CONTINUES TO MOVE EAST THROUGH ONTARIO...WHILE HIGH PRESSURE SITS OVER THE ROCKIES. LAKE EFFECT SNOW REMAINS THE MAIN PLAYER IN THE FORECAST...WITH THE MAIN DIFFICULTIES INCLUDING THE MOVEMENT OF BANDS DUE TO MINOR WIND DIRECTION CHANGES AND WHETHER ACCUMULATIONS WILL WARRANT ADDITIONAL HEADLINES. ALL MODELS AGREE ON WESTERLY COMPONENT TO LOW LEVEL FLOW AND MOIST LOW LEVELS...WITH STRONG CONVERGENCE ALONG LAKE SUPERIOR SHORELINE. 850MB TEMPS WILL NOT BE AN ISSUE AS THEY RANGE FROM -13 TO -20C WITH LAKE TEMPERATURES AROUND 4C...GENERATING LOW LEVEL CAPE. A SPOTTER FROM ROCKLAND REPORTED 3.7 INCHES OF SNOW FROM 11 PM TO 230 AM...WITH THE HOUGHTON POLICE REPORTING 3 TO 4 INCHES OF SNOW FROM 7 PM THROUGH 245 AM AND LOTS OF BLOWING SNOW. KMQT RADAR IS RECEIVING RADAR RETURNS FROM A SNOW BAND ACROSS THE TWIN LAKES AREA AND A SECOND BAND OVER HOUGHTON. CONSIDERING THE TYPICAL BEAM BLOCKAGE THAT OCCURS WITH LAKE EFFECT SNOW IN THESE AREAS...THIS IS A STRONG SIGNAL THAT BANDS ARE QUITE DEVELOPED IF RETURNS ARE NOTED AT 9000 FEET. IN ADDITION...WITH SLIGHTLY HIGHER QPF FORECASTED...DECIDED TO ISSUE A WARNING FOR MUCH OF THE NORTHWEST. THE COMBINATION OF HEAVY SNOW AND WIND GUSTS TO 30 MPH PROMPTED A WINTER STORM WARNING INSTEAD OF A LAKE EFFECT SNOW WARNING DUE TO THE ADDITIONAL HAZARD OF BLOWING SNOW AND OCCASIONAL WHITEOUT CONDITIONS. WILL CONTINUE THE LAKE EFFECT SNOW ADVISORY FOR SOUTHERN HOUGHTON COUNTY...AS CONVERGENCE IS NOT AS STRONG THERE AND SNOWFALL TOTALS SHOULD NOT BE AS HIGH. CONVERGENCE SHOULD NOT BE QUITE AS HIGH DURING THE AFTERNOON HOURS IN THE WARNED COUNTIES AS DURING THE MORNING...AND THEREFORE SNOW ACCUMULATIONS SHOULD BE SLIGHTLY LESS DURING THAT TIME PERIOD. THE EASTERN LAKESHORE WILL HAVE ITS OWN SHARE OF SNOWFALL. CONVERGENCE ALSO LOOKS RATHER FAVORABLE ALONG THE PICTURED ROCKS SHORELINE. A LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY WAS ISSUED FOR ALGER AND LUCE COUNTIES DUE TO THE SNOW THAT WILL FALL ALONG THE IMMEDIATE COAST. WHILE MODELS INDICATE THAT STRONG BANDING SNOW SHOULD OCCUR...THE ONE CONCERN IS THAT IF WINDS PICK UP ANY SOUTHERLY COMPONENT...THESE BANDS MAY OCCUR OVER WATER INSTEAD OF OVER LAND. THEN AGAIN...IF WINDS BECOME MORE NORTHWESTERLY...THERE IS THE POSSIBILITY OF A BAND PARKING ITSELF ALONG THE SHORELINE AND CAUSING WARNING-CRITERIA SNOWFALL. TONIGHT...WINDS BECOME SOUTHWESTERLY...SHUTTING OFF LAKE EFFECT OUT EAST. ALONG THE WESTERN SHORELINE...LES WILL ONLY BE ENHANCED AS A SHORTWAVE MOVES IN FROM THE WEST AND ADDS A SYNOPTIC LIFTING MECHANISM. INVERSION HEIGHTS WILL RISE BACK ABOVE 5000 FT AND SNOWFALL RATES SHOULD RAMP UP. SIMILAR TO THE ISSUES OUT EAST TODAY...THE WIND DIRECTION WILL BE A MAJOR FACTOR IN EXACTLY WHERE BANDS DEVELOP AND DROP THE GREATEST AMOUNT OF SNOW. IF WINDS PICK ONE DIRECTION AND STAY AT THAT DIRECTION...SNOWFALL TOTALS SHOULD BE RATHER HIGH IN THAT LOCATION. FRIDAY NIGHT...LES SHOULD RETURN OUT EAST AS WINDS BECOME NORTHWESTERLY AGAIN AND MOIST AIR RETURNS TO THE AREA. SNOW WILL CONTINUE ACROSS THE WESTERN LAKESHORE...ALTHOUGH RATES SHOULD BE DROPPING BY THIS TIME. BY LATE SATURDAY THE NEXT SYNOPTIC SYSTEM BEGINS TO AFFECT THE AREA. MODEL RUNS CONTINUE TO BRING THE STORM SLIGHTLY FARTHER NORTH...AND THEREFORE INCREASED POPS THROUGH THE PERIOD. INTRODUCED A SLIGHT CHANCE OF SNOW ALONG THE WISCONSIN BORDER SATURDAY MORNING...WITH THE ENTIRE AREA HAVING CHANCE POPS SATURDAY NIGHT INTO MONDAY. RECENT MODEL RUNS ARE ALSO SHOWING THAT LOW LEVEL THICKNESSES MAY ALLOW FOR A MIX OF RAIN AND SNOW ALONG THE LAKE MICHIGAN SHORELINE ON SUNDAY AFTERNOON BEFORE CHANGING BACK OVER TO ALL SNOW. ONCE THE SYSTEM MOVES OFF TO THE EAST...STRONG N-NW FLOW SHOULD REMAIN OVER THE LAKE...BRINGING THE CHANCE FOR LAKE ENHANCED/EFFECT SNOW INTO MONDAY. NO CHANGES MADE TO THE FORECAST AFTER 00Z MONDAY. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... THE FORECAST...IN PARTICULAR FOR CMX...DEPENDS ON HIGHLY ON WIND DIRECTION FOR THIS TAF PACKAGE. SAW WILL REMAIN VFR THROUGH TONIGHT...SINCE WEST AND SOUTHWEST WINDS THAT ARE EXPECTED WILL HELP DRAG DRY AIR IN FROM THE PLAINS AND KEEP LAKE EFFECT BANDS WELL AWAY FROM THE SITE. AT CMX...WIND DIRECTIONS WILL TURN A LITTLE MORE THE NORTHWEST TODAY...WHICH SHOULD PUSH THE HEAVIER LAKE EFFECT BANDS CURRENTLY OVER CMX SOUTHWARD. THUS THE FORECAST WILL RETAIN AN IDEA OF IMPROVING CONDITIONS...THOUGH NOT GETTING OUT OF MVFR SINCE SOME WEAKER LAKE EFFECT SNOW SHOWERS SHOULD CONTINUE. WINDS THEN BACK MORE WEST TO EVEN WSW THIS EVENING...WHICH WILL HELP BRING THE HEAVIER LAKE EFFECT BANDS BACK ACROSS CMX...AND HAVE INCLUDED MENTION OF LIFR TO VLIFR VSBYS AS THE BANDS MOVE THROUGH THE SITE. ANOTHER SURFACE TROUGH DROPPING SOUTH ACROSS LAKE SUPERIOR AFTER 06Z SHOULD PICK UP THE HEAVIER BANDS AND BRING THEM BACK INTO CMX AFTER 08Z. CEILING HEIGHTS FOR CMX THROUGH THE FORECAST SHOULD GENERALLY BE LOW MVFR...BUT WHENEVER THE HEAVIER BANDS ARE MOVING THROUGH THE SITE...EXPECT THE CEILINGS TO DROP AT LEAST TO LIFR. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WESTERLY GALES OF 35-40 KT WITH SLIGHTLY HIGHER GUSTS CONTINUE THIS MORNING ON LAKE SUPERIOR IN THE WAKE OF LOW PRESSURE LIFTING NORTHEAST FROM NEAR WAWA ONTARIO. THESE WINDS WILL GRADUALLY DIMINISH TODAY AS THE LOW MOVES FARTHER AWAY. HOWEVER...A TROUGH OF LOW PRESSURE CURRENTLY IN CENTRAL MANITOBA IS EXPECTED TO DROP SOUTH ACROSS LAKE SUPERIOR TONIGHT. WESTERLY WINDS WILL INCREASE AHEAD OF THIS LOW...PERHAPS REACHING GALES OVER THE SOUTHERN PORTION OF EASTERN LAKE SUPERIOR. IN THE WAKE OF THE TROUGH FRI MORNING...NW GALES ARE LIKELY...ESPECIALLY ON EASTERN LAKE SUPERIOR. HIGH PRESSURE WILL MOVE INTO THE AREA ON FRI NIGHT...ALLOWING WINDS TO FALL BELOW 20 KNOTS. HOWEVER...THIS HIGH IS EXPECTED TO QUICKLY MOVE EAST AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS. AS THIS FAIRLY DEEP LOW LIFTS TOWARDS THE AREA ON SAT NIGHT...SE WINDS WILL INCREASE TO GALES OVER THE EAST HALF OF LAKE SUPERIOR. THEN ON SUNDAY...THE LOW IS PROGGED TO MOVE ACROSS NORTHERN LAKE MICHIGAN...WHICH SHOULD LOWER THE WINDS BACK BELOW GALES...BRIEFLY. EXPECT NORTH TO NORTHWEST WINDS IN THE WAKE OF THE LOW SUNDAY NIGHT TO INCREASE BACK UP TO GALES...THEN DIMINISH ON MONDAY AS THE LOW MOVES TO NEW ENGLAND. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ001>003. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-007. LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ084. LAKE SUPERIOR...GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING FROM 2 AM TO 12 PM EST FRIDAY FOR LSZ266-267. GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ265. GALE WARNING FROM 3 AM TO 11 AM EST FRIDAY FOR LSZ265. GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ249>251-264. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ162-263. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ240>244. LAKE MICHIGAN...NONE. && $$ DISCUSSION...TAG MARINE/AVIATION...AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 443 AM EST THU NOV 29 2007 .DISCUSSION... MAIN FORECAST CONCERNS ARE PERSISTENT LES ALONG LAKE SUPERIOR SHORELINE AND NECESSARY HEADLINES. IR IMAGERY AND RUC ANALYSIS SHOW A LARGE UPPER LEVEL RIDGE ACROSS THE EASTERN UNITED STATES...AND TWO SHORTWAVES EMBEDDED IN A LARGE SCALE TROUGH PASSING ACROSS LAKE SUPERIOR. TWO UPPER LEVEL LOWS ARE NEARLY STATIONARY NEAR THE ALEUTIAN ISLANDS AND OFF BAJA CALIFORNIA. AT THE SURFACE...THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THE SNOW ACROSS THE CWA ON WEDNESDAY CONTINUES TO MOVE EAST THROUGH ONTARIO...WHILE HIGH PRESSURE SITS OVER THE ROCKIES. LAKE EFFECT SNOW REMAINS THE MAIN PLAYER IN THE FORECAST...WITH THE MAIN DIFFICULTIES INCLUDING THE MOVEMENT OF BANDS DUE TO MINOR WIND DIRECTION CHANGES AND WHETHER ACCUMULATIONS WILL WARRANT ADDITIONAL HEADLINES. ALL MODELS AGREE ON WESTERLY COMPONENT TO LOW LEVEL FLOW AND MOIST LOW LEVELS...WITH STRONG CONVERGENCE ALONG LAKE SUPERIOR SHORELINE. 850MB TEMPS WILL NOT BE AN ISSUE AS THEY RANGE FROM -13 TO -20C WITH LAKE TEMPERATURES AROUND 4C...GENERATING LOW LEVEL CAPE. A SPOTTER FROM ROCKLAND REPORTED 3.7 INCHES OF SNOW FROM 11 PM TO 230 AM...WITH THE HOUGHTON POLICE REPORTING 3 TO 4 INCHES OF SNOW FROM 7 PM THROUGH 245 AM AND LOTS OF BLOWING SNOW. KMQT RADAR IS RECEIVING RADAR RETURNS FROM A SNOW BAND ACROSS THE TWIN LAKES AREA AND A SECOND BAND OVER HOUGHTON. CONSIDERING THE TYPICAL BEAM BLOCKAGE THAT OCCURS WITH LAKE EFFECT SNOW IN THESE AREAS...THIS IS A STRONG SIGNAL THAT BANDS ARE QUITE DEVELOPED IF RETURNS ARE NOTED AT 9000 FEET. IN ADDITION...WITH SLIGHTLY HIGHER QPF FORECASTED...DECIDED TO ISSUE A WARNING FOR MUCH OF THE NORTHWEST. THE COMBINATION OF HEAVY SNOW AND WIND GUSTS TO 30 MPH PROMPTED A WINTER STORM WARNING INSTEAD OF A LAKE EFFECT SNOW WARNING DUE TO THE ADDITIONAL HAZARD OF BLOWING SNOW AND OCCASIONAL WHITEOUT CONDITIONS. WILL CONTINUE THE LAKE EFFECT SNOW ADVISORY FOR SOUTHERN HOUGHTON COUNTY...AS CONVERGENCE IS NOT AS STRONG THERE AND SNOWFALL TOTALS SHOULD NOT BE AS HIGH. CONVERGENCE SHOULD NOT BE QUITE AS HIGH DURING THE AFTERNOON HOURS IN THE WARNED COUNTIES AS DURING THE MORNING...AND THEREFORE SNOW ACCUMULATIONS SHOULD BE SLIGHTLY LESS DURING THAT TIME PERIOD. THE EASTERN LAKESHORE WILL HAVE ITS OWN SHARE OF SNOWFALL. CONVERGENCE ALSO LOOKS RATHER FAVORABLE ALONG THE PICTURED ROCKS SHORELINE. A LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY WAS ISSUED FOR ALGER AND LUCE COUNTIES DUE TO THE SNOW THAT WILL FALL ALONG THE IMMEDIATE COAST. WHILE MODELS INDICATE THAT STRONG BANDING SNOW SHOULD OCCUR...THE ONE CONCERN IS THAT IF WINDS PICK UP ANY SOUTHERLY COMPONENT...THESE BANDS MAY OCCUR OVER WATER INSTEAD OF OVER LAND. THEN AGAIN...IF WINDS BECOME MORE NORTHWESTERLY...THERE IS THE POSSIBILITY OF A BAND PARKING ITSELF ALONG THE SHORELINE AND CAUSING WARNING-CRITERIA SNOWFALL. TONIGHT...WINDS BECOME SOUTHWESTERLY...SHUTTING OFF LAKE EFFECT OUT EAST. ALONG THE WESTERN SHORELINE...LES WILL ONLY BE ENHANCED AS A SHORTWAVE MOVES IN FROM THE WEST AND ADDS A SYNOPTIC LIFTING MECHANISM. INVERSION HEIGHTS WILL RISE BACK ABOVE 5000 FT AND SNOWFALL RATES SHOULD RAMP UP. SIMILAR TO THE ISSUES OUT EAST TODAY...THE WIND DIRECTION WILL BE A MAJOR FACTOR IN EXACTLY WHERE BANDS DEVELOP AND DROP THE GREATEST AMOUNT OF SNOW. IF WINDS PICK ONE DIRECTION AND STAY AT THAT DIRECTION...SNOWFALL TOTALS SHOULD BE RATHER HIGH IN THAT LOCATION. FRIDAY NIGHT...LES SHOULD RETURN OUT EAST AS WINDS BECOME NORTHWESTERLY AGAIN AND MOIST AIR RETURNS TO THE AREA. SNOW WILL CONTINUE ACROSS THE WESTERN LAKESHORE...ALTHOUGH RATES SHOULD BE DROPPING BY THIS TIME. BY LATE SATURDAY THE NEXT SYNOPTIC SYSTEM BEGINS TO AFFECT THE AREA. MODEL RUNS CONTINUE TO BRING THE STORM SLIGHTLY FARTHER NORTH...AND THEREFORE INCREASED POPS THROUGH THE PERIOD. INTRODUCED A SLIGHT CHANCE OF SNOW ALONG THE WISCONSIN BORDER SATURDAY MORNING...WITH THE ENTIRE AREA HAVING CHANCE POPS SATURDAY NIGHT INTO MONDAY. RECENT MODEL RUNS ARE ALSO SHOWING THAT LOW LEVEL THICKNESSES MAY ALLOW FOR A MIX OF RAIN AND SNOW ALONG THE LAKE MICHIGAN SHORELINE ON SUNDAY AFTERNOON BEFORE CHANGING BACK OVER TO ALL SNOW. ONCE THE SYSTEM MOVES OFF TO THE EAST...STRONG N-NW FLOW SHOULD REMAIN OVER THE LAKE...BRINGING THE CHANCE FOR LAKE ENHANCED/EFFECT SNOW INTO MONDAY. NO CHANGES MADE TO THE FORECAST AFTER 00Z MONDAY. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... TRANSITION TO LAKE EFFECT REGIME HAS OCCURRED AS COLD FRONT HAS NOW CLEARED UPPER MI. FOR KSAW...THIS MEANS VFR CONDITIONS SHOULD PREVAIL UNDER WRLY FLOW FOR THIS FCST PERIOD. A FEW -SHSN/FLURRIES DURING THE NIGHT SHOULD NOT RESTRICT VIS BLO VFR. WHILE CIGS MAY BRIEFLY FALL TO HIGH MVFR CATEGORY AT TIMES...IT WILL NOT BE INCLUDED GIVEN HIGHER CONFIDENCE IN VFR CONDITIONS DOMINATING. AT KCMX...IT`S A DIFFERENT STORY AS WNW WINDS AND INCREASINGLY COLDER AIR LEAD TO INCREASING INTENSITY OF LES OFF LAKE SUPERIOR. A DISTURBANCE HEADING FOR THE UPPER GREAT LAKES REGION SHOULD RESULT IN THE HEAVIEST SNOW OCCURRING LATE IN THE NIGHT AND THU MORNING. LOOK FOR VIS GENERALLY IN THE IFR RANGE TO DECREASE TO LIFR OVER THE NEXT FEW HRS AS HEAVIER SNOW DEVELOPS. WINDS GUSTING TO AROUND 30KT WILL ALSO CREATE BLSN WHICH WILL BECOME MORE AND MORE OF FACTOR WITH VIS RESTRICTION AS NEW SNOW ACCUMULATES. WHILE THERE MAY BE SOME IMPROVEMENT THU AFTN...HEAVIER SNOW MAY DEVELOP AGAIN LATE AFTN/EVENING AS FOCUSED CONVERGENCE DEVELOPING OVER WRN LAKE SUPERIOR LEADS TO THE FORMATION OF MORE INTENSE SNOW BANDS. CONVERGENCE ZONE MAY LIFT JUST N OF KCMX LATE IN THE EVENING... ALLOWING FOR IMPROVING CONDITIONS. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WESTERLY GALES OF 35-40 KT WITH SLIGHTLY HIGHER GUSTS CONTINUE THIS MORNING ON LAKE SUPERIOR IN THE WAKE OF LOW PRESSURE LIFTING NORTHEAST FROM NEAR WAWA ONTARIO. THESE WINDS WILL GRADUALLY DIMINISH TODAY AS THE LOW MOVES FARTHER AWAY. HOWEVER...A TROUGH OF LOW PRESSURE CURRENTLY IN CENTRAL MANITOBA IS EXPECTED TO DROP SOUTH ACROSS LAKE SUPERIOR TONIGHT. WESTERLY WINDS WILL INCREASE AHEAD OF THIS LOW...PERHAPS REACHING GALES OVER THE SOUTHERN PORTION OF EASTERN LAKE SUPERIOR. IN THE WAKE OF THE TROUGH FRI MORNING...NW GALES ARE LIKELY...ESPECIALLY ON EASTERN LAKE SUPERIOR. HIGH PRESSURE WILL MOVE INTO THE AREA ON FRI NIGHT...ALLOWING WINDS TO FALL BELOW 20 KNOTS. HOWEVER...THIS HIGH IS EXPECTED TO QUICKLY MOVE EAST AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS. AS THIS FAIRLY DEEP LOW LIFTS TOWARDS THE AREA ON SAT NIGHT...SE WINDS WILL INCREASE TO GALES OVER THE EAST HALF OF LAKE SUPERIOR. THEN ON SUNDAY...THE LOW IS PROGGED TO MOVE ACROSS NORTHERN LAKE MICHIGAN...WHICH SHOULD LOWER THE WINDS BACK BELOW GALES...BRIEFLY. EXPECT NORTH TO NORTHWEST WINDS IN THE WAKE OF THE LOW SUNDAY NIGHT TO INCREASE BACK UP TO GALES...THEN DIMINISH ON MONDAY AS THE LOW MOVES TO NEW ENGLAND. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ001>003. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-007. LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ084. LAKE SUPERIOR...GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LSZ266-267. GALE WARNING FROM 2 AM TO 12 PM EST FRIDAY FOR LSZ266-267. GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ265. GALE WARNING FROM 3 AM TO 11 AM EST FRIDAY FOR LSZ265. GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR LSZ249>251-264. GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ263. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ240>244. LAKE MICHIGAN...NONE. && $$ DISCUSSION...TAG MARINE...AJ AVIATION...ROLFSON mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1234 AM EST THU NOV 29 2007 UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE .UPDATE (ISSUED AT 1030 PM EST)... MAIN FCST CONCERN IS EXPECTED INCREASE IN LES OVERNIGHT/THU. OF MOST IMPORTANCE TO LES FCST IS THE SHORTWAVE CURRENTLY DROPPING ESE THRU NE ND INTO MN PER WATER VAPOR IMAGERY AND RUC ANALYSIS. AS THIS SHORTWAVE CONTINUES ESE...00Z RUC/NAM SHOW A PERIOD OF DEEP LAYER FORCING SPREADING OVER WRN LAKE SUPERIOR BTWN 06-09Z AND REACHING ERN LAKE SUPERIOR 09-12Z. UPSTREAM 00Z KINL SOUNDING SHOWED 850MB TEMP OF -19C...INVERSION AROUND 825MB (5KFT MSL) AND A MOIST PROFILE THRU 500MB. WOULD EXPECT A RAISING OF THE INVERSION AS SHORTWAVE APPROACHES...AND THAT IS WHAT RUC/NAM FCST SOUNDINGS INDICATE. SO...CONDITIONS WILL BECOME FAVORABLE FOR A PERIOD OF HVY LES FROM ROUGHLY THE PORCUPINE MOUNTAINS N THRU THE KEWEENAW... ESPECIALLY CONSIDERING THE FAVORABLE DENDRITIC SNOW GROWTH TEMPS IN THE CONVECTIVE LAYER. IN THE GRID FCST UPDATE THAT HAS ALREADY BEEN ISSUED...BUMPED UP SNOW ACCUMULATIONS TO THE EDGE OF WARNING CRITERIA (8 INCHES/12HRS) FOR THE 06-12Z AND 12Z-18Z TIME FRAME COMBINED. RUC/NAM SUGGEST LAKE INDUCED TROFFING MAY FOCUS CONVERGENCE INTO THE AREA BTWN ROCKLAND AND PAINESDALE WHICH IS QUITE REASONABLE. HAVE THUS INDICATED THE HIGHEST SNOW ACCUMULATIONS THERE (NEAR 8 INCHES FROM 06-18Z). ALSO...INCLUDED BLSN WITH W WINDS GUSTING TO AROUND 30 MPH. TO THE E...WINDS WILL HAVE ENOUGH OF A W COMPONENT THAT ONLY THE SHORELINE AREAS FROM AROUND GRAND MARAIS EWD SHOULD BE AFFECTED BY DEVELOPING LES. INCREASED SNOW ACCUMULATIONS THERE FOR LATE IN THE NIGHT AND THU MORNING. THERE IS SOME CONCERN THAT LAND BREEZE COMPONENT TO WIND WILL BECOME STRONG ENOUGH TO PUSH MAIN LES JUST OFFSHORE. HAVE THUS HELD OFF ON A HEADLINE THERE FOR NOW. && .SHORT TERM (TONIGHT AND THU)... TAKING A LOOK AT THE LATEST WEATHER MAPS...THE SURFACE LOW WAS CENTERED NEAR CMX. LOOKING AT THE WATER VAPOR IMG...PLENTY OF DRY AIR WAS BEHIND THE COLD FRONT...WHILE MUCH OF THE MOIST AIR WAS POSITIONED ACROSS THE NORTHEASTERN UPPER PENINSULA. THE 500MB TROUGH WAS SCOOTING INTO WESTERN MINNESOTA. AFTER SOME BRIEF ZONAL FLOW BEFORE MIDNIGHT...A SECONDARY WEAK TROUGH IS FIGURED TO SLIDE IN DURING THE EARLY MORNING HOURS. DRIER AIR HAMPERED MUCH HIGHER SNOW AMOUNTS ACROSS THE UPPER PENINSULA TODAY AS WELL AS SLIGHTLY WARMER THAN EXPECTED TEMPERATURES. BOTH MNM AND ESC GOT THE MID 30S F. EVEN AS FAR NORTH AS SAW THIS AFTERNOON WE WERE ABLE GET TO 30F...BRINGING ABOUT -FZDZ IN THE METAR. LAKE EFFECT SNOW OVER KEWEENAW...N/S HOUGHTON AND ONTONAGON ARE STILL A GOOD BET FOR THROUGH AT LEAST THURSDAY AS WINDS BECOME MORE WESTERLY BEHIND THE LOW. AT CMX SPECIFICALLY...WHERE WINDS HAVE TURNED MORE SOUTHERLY AT 19Z...SHUTTING OFF MUCH OF THE SNOW BEFORE BECOMING WESTERLY BRINGING BACK MORE SNOW SHOWERS. A LAKE EFFECT SNOW ADVISORY HAS BEEN POSTED THROUGH THURSDAY AFTERNOON. .LONG TERM (THURSDAY NIGHT THROUGH WEDNESDAY)... MAIN FCST CONCERNS SHIFT FROM LES OVER NW UPPER MI TO SNOW POTENTIAL ACROSS THE AREA LATE SAT INTO SUN WITH ADDITIONAL LES NEXT WEEK. THURSDAY NIGHT AND FRIDAY...THE MODELS WERE CONSISTENT IN BRINGING ANOTHER SHORTWAVE LOBE THROUGH THE UPPER GREAT LAKES. THE GLOBAL MODELS AND REGIONAL CANADIAN GEM WERE PREFERRED WITH THIS FEATURE COMPARED TO THE SLOWER NAM. WRLY FLOW LES WILL CONTINUE INTO NW UPPER MI. AS THE SHORTWAVE TROUGH MOVES THROUGH DEEPER MOISTURE WITH HIGHER INVERSION HEIGHTS WILL BOOST LES SNOWFALL RATES...ESPECIALLY BTWN 06Z-18Z/FRI. THE DEEP COLD AIR (850 MB TEMPS NEAR -20C AND 700 MB TEMPS AROUND -26C) WILL PROVIDE PLENTY OF INSTABILITY WITH LAKE INDUCED CAPE VALUES INTO THE 500-800 J/KG RANGE. THE HEIGHT AND DEPTH OF THE -12C TO -17C LAYER IS A BIT LOW/SHALLOW BUT SHOULD STILL ALLOW FOR DECENT SNOWFLAKE GROWTH. THE LOCAL HIGH RES WRF/ARW...CONSISTENT WITH THE GFS...SUGGESTS THAT THE MORE PERSISTENT AREA OF 950 MB CONVERGENCE WOULD ALIGN FROM THE APOSTLE ISLANDS TOWARD NRN ONTONAGON COUNTY AND NEAR M-38 WHILE THE NAM...AS WOULD BE EXPECTED WITH THE SLOWER SHORTWAVE KEEPS THE LOW LEVEL CONV FARTHER NORTH(FROM KCMX TO KP59). EITHER SCENARIO WOULD EVENTUALLY BRING VEERING WINDS WITH THE CONV AXIS SAGGING SOUTH. SO...UNCERTAINTY REMAINS IN HOW THE LOW LEVEL WIND FIELDS WILL RESPOND AND WHERE/WHEN ANY DOMINANT BANDS WILL SET UP AND HOW LONG THEY WOULD PERSIST AT ANY LOCATION. SO...THE FCST KEEPS MORE CONSERVATIVE SNOWFALL AMOUNTS IN THE ADVISORY RANGE WITH 12 HOUR AMOUNTS OF 2-5 INCHES. IF CONFIDENCE INCREASES WITH BAND(S) PLACEMENT THE LES ADVISORY COULD BE EXTENDED AND/OR UPGRADED. FRIDAY NIGHT...WITH VERY COLD AIR REMAINING OVER THE REGION...THE LES WILL PERSIST BUT SHOULD DIMINISH AS DRIER MOVE IN...INVERSION HEIGHTS LOWER...ACYC FLOW DEVELOPS AND WINDS SHIFT OFFSHORE AS WINDS BACK WITH THE SFC RIDGE MOVING THROUGH. SATURDAY INTO MON...THE FCST LEANS MORE TOWARD HPC PREFERRED 00Z ECMWF WHICH IS CLOSELY SUPPORTED BY THE CANADIAN GLOBAL. THE 12Z UKMET DEEPENS THE LOW A BIT SOONER AND WAS FASTER MOVING IT NE OF THE GREAT LAKES INTO MON. POTENTIAL FOR SNOW WILL SPREAD ACROSS THE REGION LATE SAT INTO SAT NIGHT AS A BROAD WAA/ISENTROPIC LIFT PATTERN DEVELOPS AHEAD OF THE DEVELOPING LOW OVER THE PLAINS. THE LOW SHOULD INTENSIFY AND MOVE TOWARD LAKE HURON BY MON MORNING AS THE MID LEVEL TROUGH AND SHORTWAVE ENERGY MOVES FROM THE SW AND SRN PLAINS LIFTS QUICKLY NE. POPS WERE INCREASED WITH EXPECTATION THAT EVENTUALLY LIKELY OR CATEGORICAL POPS WILL BE NEEDED AS UNCERTAINTY WITH TIMING AND STRENGTH OF THESE FEATURES ARE RESOLVED. MODERATE TO HEAVY LAKE EFFECT OR LAKE ENHANCED SNOW IS ALSO POSSIBLE OVER NORTH UPPER MI FOR LOCATIONS FAVORED BY N OR NW FLOW. TUE-WED...ECMWF 850 MB TEMPS AOB -15C ALONG WITH NW FLOW SHOULD KEEP LES GOING OVER NORTH UPPER MICHIGAN. THERE ALSO MAY BE THE POTENTIAL FOR WEAK CLIPPER SHORTWAVES TO MOVE THROUGH THE AREA IN NW FLOW PATTERN. THIS WOULD BOOST AND/OR SHIFT LAKE EFFECT BANDS AND COULD BRING SOME LIGHT SNOW TO SOUTH UPPER MI. HOWEVER...HIGH UNCERTAINTY REMAINS WITH TIMING/STRENGTH OF THESE FEATURES AT DAYS 6/7. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... TRANSITION TO LAKE EFFECT REGIME HAS OCCURRED AS COLD FRONT HAS NOW CLEARED UPPER MI. FOR KSAW...THIS MEANS VFR CONDITIONS SHOULD PREVAIL UNDER WRLY FLOW FOR THIS FCST PERIOD. A FEW -SHSN/FLURRIES DURING THE NIGHT SHOULD NOT RESTRICT VIS BLO VFR. WHILE CIGS MAY BRIEFLY FALL TO HIGH MVFR CATEGORY AT TIMES...IT WILL NOT BE INCLUDED GIVEN HIGHER CONFIDENCE IN VFR CONDITIONS DOMINATING. AT KCMX...IT`S A DIFFERENT STORY AS WNW WINDS AND INCREASINGLY COLDER AIR LEAD TO INCREASING INTENSITY OF LES OFF LAKE SUPERIOR. A DISTURBANCE HEADING FOR THE UPPER GREAT LAKES REGION SHOULD RESULT IN THE HEAVIEST SNOW OCCURRING LATE IN THE NIGHT AND THU MORNING. LOOK FOR VIS GENERALLY IN THE IFR RANGE TO DECREASE TO LIFR OVER THE NEXT FEW HRS AS HEAVIER SNOW DEVELOPS. WINDS GUSTING TO AROUND 30KT WILL ALSO CREATE BLSN WHICH WILL BECOME MORE AND MORE OF FACTOR WITH VIS RESTRICTION AS NEW SNOW ACCUMULATES. WHILE THERE MAY BE SOME IMPROVEMENT THU AFTN...HEAVIER SNOW MAY DEVELOP AGAIN LATE AFTN/EVENING AS FOCUSED CONVERGENCE DEVELOPING OVER WRN LAKE SUPERIOR LEADS TO THE FORMATION OF MORE INTENSE SNOW BANDS. CONVERGENCE ZONE MAY LIFT JUST N OF KCMX LATE IN THE EVENING... ALLOWING FOR IMPROVING CONDITIONS. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE ACROSS THE AREA WILL CONTINUE TO LIFT UP INTO EASTERN ONTARIO THIS EVENING. AFTER A BRIEF PERIOD OF LIGHTER WINDS AS THE LOW CROSSES...EXPECT WEST TO NORTHWEST WINDS TO DEVELOP WITH GALES TO 35 KT ON WESTERN LAKE SUPERIOR BY LATE EVENING...THEN OVER EASTERN LAKE SUPERIOR LATE NEAR 45 KTS EARLY AND AGAIN LATE TONIGHT. OTHERWISE...A BREAK FROM THE GALES IS FIGURED THURSDAY EVENING THROUGH SATURDAY. HOWEVER...FRIDAY AFTERNOON COULD SEE A BRIEF REAMERGENCE OVER EASTERN LAKE SUPERIOR. THEN...A DEEPENING LOW WILL NEAR FROM THE CENTRAL PLAINS OVER THE WEEKEND...BRINGING BACK THE POTENTIAL FOR GALES THROUGH MONDAY NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...LAKE EFFECT SNOW ADVY UNTIL 4 PM EST THU MIZ001>003-084. LAKE SUPERIOR...GALE WARNING UNTIL 3 PM EST THU LSZ266-267. GALE WARNING UNTIL 1 PM EST THU LSZ265. GALE WARNING UNTIL 12 PM EST THU LSZ264. GALE WARNING UNTIL 9 AM THU LSZ162-263. GALE WARNING FROM 1 AM TO 2 PM EST THU LSZ248>251. GALE WARNING FROM 1 AM TO 2 PM EST THU LSZ243-244. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THU LSZ240>242. && $$ UPDATE...ROLFSON SHORT TERM...KF LONG TERM...JLB AVIATON...ROLFSON MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 306 AM CST FRI NOV 30 2007 .DISCUSSION... FORECAST FOCUS CONTINUES TO BE ON THE IMPENDING WINTER STORM FOR SATURDAY AND SATURDAY NIGHT. IN THE NEAR TERM...SKIES CLEARING QUITE NICELY IN THE WAKE OF THE QUICK MOVING SHORT WAVE THAT BROUGHT A LITTLE SNOW TO SOUTHERN MINNESOTA TONIGHT. TEMPERATURES ARE A LITTLE CHILLY...BUT THE WINDS...WHICH HAVE REMAINED UP OVERNIGHT...HAVE SOMEWHAT PREVENTED A TOTAL BOTTOM OUT IN TEMPERATURES. DEW POINTS SHOULD CRASH LATER TODAY...AS THE SURFACE HIGH OVER THE DAKOTAS MAKES A CLOSER APPROACH. SKIES TODAY SHOULD REMAIN MOSTLY SUNNY...BUT TEMPERATURES SHOULD ONLY BE A FEW DEGREES WARMER THAN YESTERDAYS. THE BIG CHANGE BEGINS TO HAPPEN EARLY SATURDAY MORNING...AS RETURN FLOW PICKS UP RATHER QUICKLY ON THE BACKSIDE OF THE DEPARTING HIGH...RESULTING IN A FAIRLY RAPID INCREASE IN MOISTURE AND WARM ADVECTION...AS THE SURFACE LOW BEGINS TO MOVE OUT OF THE ROCKIES. THE STRONG WARM ADVECTION IS REFLECTED IN THE VERY STRONG ISENTROPICS IN ADVANCE OF THE SYSTEM...WHICH WILL FUEL THE STORM. THE MODELS CONTINUE TO HAVE SUBTLE DIFFERENCES... ESPECIALLY REGARDING THE PLACEMENT OF THE WARM NOSE. A MIX SEEMS INEVITABLE ACROSS A GOOD PORTION OF THE FORECAST AREA...WITH MOSTLY FREEZING RAIN ACROSS FAR SOUTHERN MINNESOTA /INTERSTATE 90 CORRIDOR/...AND SLEET SOUTH OF THE TWIN CITIES. LOCATIONS NORTH OF THE TWIN CITIES...AND ACROSS WESTERN MINNESOTA...SHOULD SEE ALL SNOW FROM THIS EVENT. UNFORTUNATELY...THE TWIN CITIES IS IN THAT QUESTION MARK ZONE...WHERE...DEPENDING ON HOW FAR NORTH THE LOW TRACKS...THERE MIGHT BE MORE SLEET THAN SNOW. AS A RESULT...WE HAVE ADDED A MENTION OF SLEET ON SATURDAY EVENING TO THE AREA INCLUDING THE TWIN CITIES. SIGNIFICANT SNOW TOTALS STILL LOOK LIKELY...ESPECIALLY ACROSS NORTHERN SECTIONS OF THE FORECAST AREA...WHERE CLOSE TO A FOOT AMOUNTS LOOK POSSIBLE. WITH SO MANY QUESTION MARKS REMAINING...FEW CHANGES HAVE BEEN MADE TO THE GOING WEATHER TYPE...QPF...OR SNOW AMOUNT FORECASTS...WHICH WERE LARGELY SUFFICIENT TO ILLUSTRATE WHAT THE CURRENT MODEL DATA ARE SAYING. THE MAIN TWEAKS WERE TO BRING THE MENTION OF MIXED PRECIP TYPES A LITTLE FARTHER NORTH THAN WERE PREVIOUSLY THERE. WRAPAROUND SNOW SHOULD LARGELY BE DONE BY MONDAY...LEAVING A BRIEF DRY SPELL...BEFORE A CLIPPER DROPS SOUTHEASTWARD...BRINGING ANOTHER CHANCE OF LIGHTER SNOW TO THE AREA. THE BIG QUESTIONS IN THE EARLY PART OF THE EXTENDED REVOLVE AROUND TEMPERATURES. THE LATEST GFS AND ECMWF ILLUSTRATE A NICE WARM UP INTO TUESDAY. HAVE NOT COMPLETELY BIT INTO THIS AS OF YET...BUT DID WARM UP TEMPERATURES A SHADE FOR MONDAY NIGHT AND TUESDAY. && .AVIATION.../06Z TAF ISSUANCE/ LATEST RUC MODEL RUN FROM 00Z CARRIES SHORT WAVE ENERGY EASTWARD FROM SOUTHEAST MINNESOTA INTO SOUTHERN WISCONSIN BY 09Z WITH STRONG DRYING INDICATED INTO CENTRAL WISCONSIN. THIS IS IN LINE WITH A LOOP OF MOISTURE CHANNEL IMAGERY AS WELL AS IR IMAGERY THAT SHOWS COLDER TOPS MOVING OUT OF EAST CENTRAL MN INTO WESTERN WISCONSIN. THERE IS A RISK OF LGT SNOW WITH LOCAL VISBYS FROM 5 TO 6 MILES AT KEAU...KMSP AND KRNH THROUGH ABOUT 07Z WITH CLEAR SKIES EXPECTED FOR ALL TAF SITES SHORTLY AFTER SUNRISE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA- CHISAGO-DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN- ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN- MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY- REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE- STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK- RUSK-ST. CROIX. && $$ KAT/WET mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1051 PM CST THU NOV 29 2007 .UPDATE... SHORT WAVE CURRENTLY MOVING QUICKLY EAST ACROSS IOWA WITH A STATIONARY FRONT AT THE SURFACE. SOME UPGLIDE OVER THIS SURFACE FEATURE AND ACCOMPANYING WEAK FULL WIND FRONTOGENETIC FORCING HAS LED TO SNOW ACCUMULATIONS OF POSSIBLY AN INCH. SECONDARY COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA OVERNIGHT AND WITH GRADUAL CLEARING STILL LOOKS TO YIELD NEAR ZERO TEMPERATURES BY ALEXANDRIA AND LITTLE FALLS NEAR DAYBREAK. MAIN NCEP OPERATIONAL MODELS /NAM AND GFS/ AT 00Z HAVE COME IN MARKEDLY SIMILAR TO THEIR 18Z RUNS. THE 21Z SHORT RANGE ENSEMBLE FORECAST IS ALSO SIMILAR TO ITS PRIOR RUNS. PATH AND EVOLUTION OF 850MB AND 700MB LOWS AND ROUGH ESTIMATES ON MEAN QPF GIVEN MODEL PARAMETERS ARE ALL SIMILAR AT LEAST TO THE NAKED EYE. MID-SHIFT WILL BE TAKING A MORE IN DEPTH LOOK AT IT. && .PREV DISCUSSION... /ISSUED 904 PM CST THU NOV 29 2007/ WAVE OF LOW PRESSURE TO MOVE EASTWARD ACROSS SOUTHERN MN AND WI THIS EVENING ALONG BAROCLINIC ZONE ACROSS THE REGION. 285K THETA SURFACE SHOWS SATURATION DEVELOPING ACROSS SOUTH CENTRAL AND SOUTHEAST MN BY THIS EVENING AND SPREADING EASTWARD. SREF/RUC CONTINUE TO SHOW A SMALL AREA OF SNOW DEVELOPING. INCREASED POPS TO LIKELY FOR THIS EVENING TO THE SOUTH OF A LINE FROM THE TWIN CITIES TO EAU CLAIRE. OBSERVATIONS TO OUR WEST SHOW THE CEILINGS CONTINUING TO FALL WITH KATV NOW SHOWING A LITTLE LIGHT SNOW. EXPECT SNOW FALL AMOUNTS TO BE LESS THAN 1 INCH. HIGH PRESSURE TO FOLLOW IN FOR FRIDAY AND FRIDAY NIGHT WITH CLEAR SKIES AND ANOTHER ROUND OF COLD TEMPERATURES NOT ONLY TONIGHT BUT AGAIN FRIDAY NIGHT. UPCOMING WEEKEND LOOKING BETTER FOR SIGNIFICANT SNOW. 12Z GFS AND ECMWF ALMOST ON TOP OF ONE ANOTHER FOR THE ENTIRE EVENT WHILE THE SREF AND GEFS ARE ALIGNED. STRONG WAA FOR SATURDAY WITH SNOW DEVELOPING SW IN THE MORNING AND QUICKLY SPREADING NORTHEAST. SINGLE RUNS OF THE GFS AND ECMWF SHOW FREEZING RAIN AND SLEET BECOMING LIKELY LATE IN THE DAY SATURDAY AND FOR A TIME SATURDAY NIGHT. IN ADDITION BEST LI`S ARE BETWEEN 0 AND -2 ACROSS FAR SOUTHERN MN ALONG WITH ELEVATED CAPE ABOVE 750 MB. FOR NOW HAVE INTRODUCED SOME SLEET AND FREEZING RAIN FOR FAR SOUTHERN MN. SREF/GEFS NOT AS AGGRESSIVE ON THE WARM AIR PUSH. FWF AND PREFERRED ICE GROWTH FROM THE SREF TEMPERATURES WOULD INDICATE THE BEST SNOW ATTM FROM SOUTHWEST MN THROUGH THE TWIN CITIES AND INTO NORTHERN WI. THE GFS AND ECMWF HAVE A CLOSE LOW AT 700 MB PASSING ACROSS WEST CENTRAL THROUGH NE MN. THIS WOULD GIVE YOU MORE POTENTIAL FOR HEAVY SNOW BEING FURTHER WEST AND NORTH. FOR NOW COLLABORATION WAS TO ISSUE A WINTER STORM WATCH...WITH EVERYONE ON BOARD...FOR SATURDAY INTO SUNDAY. PLENTY OF TIME TO WORK OUT THE DETAILS AS THE HEAVIEST SNOW WILL NOT OCCUR UNTIL SATURDAY AFTERNOON AND SATURDAY NIGHT. IN THE WAKE OF THIS SYSTEM... NORTHWEST FLOW RETURNS. A CLIPPER IS PROGGED TO PASS US TUESDAY INTO WEDNESDAY WITH A CHANCE OF LIGHT SNOW. DRY WEATHER FOR THURSDAY. && .AVIATION.../06Z TAF ISSUANCE/ LATEST RUC MODEL RUN FROM 00Z CARRIES SHORT WAVE ENERGY EASTWARD FROM SOUTHEAST MINNESOTA INTO SOUTHERN WISCONSIN BY 09Z WITH STRONG DRYING INDICATED INTO CENTRAL WISCONSIN. THIS IS IN LINE WITH A LOOP OF MOISTURE CHANNEL IMAGERY AS WELL AS IR IMAGERY THAT SHOWS COLDER TOPS MOVING OUT OF EAST CENTRAL MN INTO WESTERN WISCONSIN. THERE IS A RISK OF LGT SNOW WITH LOCAL VISBYS FROM 5 TO 6 MILES AT KEAU...KMSP AND KRNH THROUGH ABOUT 07Z WITH CLEAR SKIES EXPECTED FOR ALL TAF SITES SHORTLY AFTER SUNRISE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA- CHISAGO-DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN- ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN- MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY- REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE- STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK- RUSK-ST. CROIX. && $$ mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 904 PM CST THU NOV 29 2007 .DISCUSSION... WAVE OF LOW PRESSURE TO MOVE EASTWARD ACROSS SOUTHERN MN AND WI THIS EVENING ALONG BAROCLINIC ZONE ACROSS THE REGION. 285K THETA SURFACE SHOWS SATURATION DEVELOPING ACROSS SOUTH CENTRAL AND SOUTHEAST MN BY THIS EVENING AND SPREADING EASTWARD. SREF/RUC CONTINUE TO SHOW A SMALL AREA OF SNOW DEVELOPING. INCREASED POPS TO LIKELY FOR THIS EVENING TO THE SOUTH OF A LINE FROM THE TWIN CITIES TO EAU CLAIRE. OBSERVATIONS TO OUR WEST SHOW THE CEILINGS CONTINUING TO FALL WITH KATV NOW SHOWING A LITTLE LIGHT SNOW. EXPECT SNOW FALL AMOUNTS TO BE LESS THAN 1 INCH. HIGH PRESSURE TO FOLLOW IN FOR FRIDAY AND FRIDAY NIGHT WITH CLEAR SKIES AND ANOTHER ROUND OF COLD TEMPERATURES NOT ONLY TONIGHT BUT AGAIN FRIDAY NIGHT. UPCOMING WEEKEND LOOKING BETTER FOR SIGNIFICANT SNOW. 12Z GFS AND ECMWF ALMOST ON TOP OF ONE ANOTHER FOR THE ENTIRE EVENT WHILE THE SREF AND GEFS ARE ALIGNED. STRONG WAA FOR SATURDAY WITH SNOW DEVELOPING SW IN THE MORNING AND QUICKLY SPREADING NORTHEAST. SINGLE RUNS OF THE GFS AND ECMWF SHOW FREEZING RAIN AND SLEET BECOMING LIKELY LATE IN THE DAY SATURDAY AND FOR A TIME SATURDAY NIGHT. IN ADDITION BEST LI`S ARE BETWEEN 0 AND -2 ACROSS FAR SOUTHERN MN ALONG WITH ELEVATED CAPE ABOVE 750 MB. FOR NOW HAVE INTRODUCED SOME SLEET AND FREEZING RAIN FOR FAR SOUTHERN MN. SREF/GEFS NOT AS AGGRESSIVE ON THE WARM AIR PUSH. FWF AND PREFERRED ICE GROWTH FROM THE SREF TEMPERATURES WOULD INDICATE THE BEST SNOW ATTM FROM SOUTHWEST MN THROUGH THE TWIN CITIES AND INTO NORTHERN WI. THE GFS AND ECMWF HAVE A CLOSE LOW AT 700 MB PASSING ACROSS WEST CENTRAL THROUGH NE MN. THIS WOULD GIVE YOU MORE POTENTIAL FOR HEAVY SNOW BEING FURTHER WEST AND NORTH. FOR NOW COLLABORATION WAS TO ISSUE A WINTER STORM WATCH...WITH EVERYONE ON BOARD...FOR SATURDAY INTO SUNDAY. PLENTY OF TIME TO WORK OUT THE DETAILS AS THE HEAVIEST SNOW WILL NOT OCCUR UNTIL SATURDAY AFTERNOON AND SATURDAY NIGHT. IN THE WAKE OF THIS SYSTEM... NORTHWEST FLOW RETURNS. A CLIPPER IS PROGGED TO PASS US TUESDAY INTO WEDNESDAY WITH A CHANCE OF LIGHT SNOW. DRY WEATHER FOR THURSDAY. && .AVIATION.../00Z TAF ISSUANCE/ POWERFUL JET CORE OF 170 KNOTS EXTENDS ACROSS NORTHERN NEBRASKA AND IOWA INTO SOUTHERN WISCONSIN THIS EVENING. FRONTOGENETIC FORCING IS OCCURRING ON THE CYCLONIC SIDE OF THIS JET MAX AND IS SETTING OFF MVFR CIGS AND VSBYS TO THE WEST AND SOUTH OF MSP WITH LOCAL IFR CONDITIONS QUITE WIDESPREAD FROM NEAR KMKT WEST TO THE SOUTH DAKOTA BORDER. VERTICAL MOTION DROPS OFF QUICKLY AFTER 06Z THIS EVENING SO IMPROVEMENT IS EXPECTED. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA- CHISAGO-DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN- ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN- MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY- REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE- STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK- RUSK-ST. CROIX. && $$ 99/99/99 mn AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 100 PM PM CST FRI NOV 30 2007 .UPDATE... NEW GRIDS HAVE BEEN SENT FOR TODAY. && .DISCUSSION... MAIN FORECAST CONCERN IS BEYOND THE 1ST PERIOD WITH POTENTIAL ICE STORM AFFECTING THE AREA BEGINNING LATER TONIGHT AND LINGERING THROUGH MUCH OF SATURDAY. POTENT UPPER TROUGH NOW MOVING INTO THE WESTERN CONUS WITH WIDESPREAD 60 TO 120M HEIGHT FALLS...ALONG WITH A SIGNIFICANT FETCH OF PACIFIC MOISTURE MOVING THROUGH THE 4 CORNERS REGION. MODELS REMAIN IN GOOD AGREEMENT TODAY AND IT`S NOT SO MUCH OF A QUESTION OF IF IT WILL OCCUR...BUT WHEN AND WHAT PRECIP TYPE. GIVEN THE STRENGTH OF THE COLD AIR AT THE SURFACE...FREEZING RAIN APPEARS TO BE THE MAIN THREAT ALONG AND SOUTH OF THE I80 CORRIDOR AS WARM AIR ALOFT MOVES IN FROM THE SOUTHWEST. SOUNDING PROFILES INDICATE THAT PRECIP WILL LIKELY BEGIN AS SLEET...BUT QUICKLY CHANGE OVER TO FREEZING RAIN AS TOP DOWN APPROACH INDICATES WARM WEDGE ALOFT WILL DEFINITELY EXCEED 3 DEGREES C WHICH SHOULD ALLOW FOR COMPLETE MELTING. PRECIP AMOUNTS COULD EASILY REACH ONE QUARTER TO THREE QUARTERS OF AN INCH. THE GOOD NEWS...THE SURFACE TEMPERATURES SHOULD QUICKLY RISE ACROSS SERN HALF THE CWFA FROM SOUTHWEST TO NORTHEAST FROM LATE MORNING THROUGH EARLY AFTERNOON WHICH SHOULD HELP TO MELT SOME OF THE ICE ACCUMULATIONS. ACROSS NORTHEAST NEBRASKA...PRECIP SHOULD REMAIN A MIXTURE OF SLEET AND FREEZING RAIN A BIT LONGER. NOT EXPECTING MUCH SNOWFALL UP THERE...AND TEMPS COULD BRIEFLY GO ABOVE FREEZING IN THE AFTERNOON...BUT THEN GO BACK BELOW AND CHANGE BACK OVER TO SNOW AS THE COLDER AIR SATURATES THE COLUMN. THUS WOULD EXPECT THE WINTER EVENT TO LAST A BIT LONGER UP THERE. WE`RE IN THE PROCESS OF MAKING FINAL DECISIONS REGARDING UPGRADING THE WINTER STORM WATCH THAT WE CURRENTLY HAVE IN EFFECT. WILL LIKELY BE UPGRADING TO A COMBINATION OF ICE STORM WARNINGS ACROSS THE AREA. TIMING OF BEGINNING AND ENDING WILL ALSO BE INCORPORATED INTO NEW WSW HEADLINES WHICH WILL BE ISSUED LATER THIS AFTERNOON. && .AVIATION... AM EXPECTING DETERIORATING CONDITIONS AT ALL 3 TAF SITES WITH A MIXTURE OF SLEET AND FREEZING RAIN MOVING IN...INITIALLY AT KLNK BY 8Z AND KOMA AND KOFK BY 10Z. MAYBE ABOUT TWO HOURS OF SLEET... THEN CHANGING OVER TO ALL FREEZING RAIN. CIGS FALL RAPIDLY ONCE THE PRECIP MOVES IN...GOING FROM OVC250 CURRENTLY TO AOB OVC010 AFT 10-12Z. WINDS WILL BE SWITCHING FROM NORTHERLY TO SOUTHEASTERLY... AND SUBSTANTIALLY INCREASING TO AOA 20KT BY 12Z. && .PREV DISCUSSION... /ISSUED 350 AM CST FRI NOV 30 2007/ DISCUSSION... OBVIOUSLY PRECIPITATION TYPE/AMOUNTS WITH SYSTEM LATE TONIGHT AND SATURDAY IS THE MAIN FORECAST CONCERN AND FOCUS...AND LITTLE/NO CHANGES WERE MADE IN THE EXTENDED. SINCE MAIN EVENT WILL PROBABLY BE IN 09Z-00Z PERIOD ON SATURDAY...NO UPGRADE YET TO WATCH WILL BE MADE. OVERALL QPF AMOUNTS FOR THE EVENT COULD EASILY SURPASS 0.5 INCHES...AND POSSIBLY REACH 1 INCH IN SPOTS AS PRECIPITABLE WATER VALUES ARE FORECAST TO CROSS 1 INCH. IT WAS NOTED ON LAST NIGHTS UA ANLYS THAT THE 850 MB DWPT AT TUCSON WAS 11 DEG C SO NOT ONLY WILL THIS SYSTEM TAP GULF MOISTURE...IT LOOKS LIKE IT WILL BE BRINGING AMPLE PACIFIC MOISTURE WITH IT AS WELL. THUS...IN THE SHORTER TERM TODAY AND TONIGHT. MODIFIED ARCTIC AIRMASS HAS BROUGHT SHALLOW COLD/DRY AIR ACROSS THE CWA WHICH WAS NOT HANDLED WELL BY THE 00Z GFS AND EVEN 06Z NAM...BOTH OF WHICH WERE TOO WARM. LATEST RUC HANDLED IT BETTER AND IT WAS ABOUT 5 DEGREES COOLER BY 18Z. HRLY TEMPS/MAX TEMPS WILL BE ADJUSTED THAT WAY...WHICH WILL GENERALLY BE A DOWNWARD ADJUSTMENT. FOR TONIGHT...VERY STRONG WARM ADVCTN DEVELOPS WITH NAM/ECMWF FORECASTING AN 850 MB JET OF 40-45 KTS ACROSS THE CWA BY 12Z SAT. IN FACT...BOTH OF THOSE MODELS INCREASED THIS JET INTO THE 70-75 KT RANGE DURING THE DAY SAT...WHICH IS QUITE IMPRESSIVE. BASED ON FORECAST SOUNDINGS FREEZING RAIN OR A FREEZING RAIN/SLEET MIX IS THE MOST LIKELY OUTCOME FOR MUCH OF THE PCPN UNTIL TEMPS CAN WARM ABOVE FREEZING...WHICH LOOKS LIKE IT WON/T BE UNTIL SOMETIME SATURDAY AFT 12Z. NEEDLESS TO SAY WITH SUCH A COLD/DRY AIRMASS TO BEGIN THIS EVENT...SIGNIFICANT ICING IS POSSIBLE WITH MAIN FLY IN THE PCPN OINTMENT SO TO SPEAK BEING HOW MUCH SLEET WILL FALL OR MIX IN. ALTHOUGH 1000-500 MB THICKNESSES FORECAST FOR TONIGHT WERE A BIT TOO WARM FOR SNOW...FORECAST SOUNDINGS DO SUPPORT A CHC OF IT TO BEGIN THE EVENT...ALTHOUGH QUITE BRIEF SRN HALF OF THE CWA. WL MENTION SOME 1/2-1 INCH SNOW ACCUMULATIONS NORTH TNGT TAPERING OFF TO ONE/TWO TENTHS ALONG PLATTE RIVER AND NOTHING S OF THERE INCLUDING 4 SW IA COUNTIES. /DID ALSO LINGER SOME 1-2 INCH ADDITIONAL AMOUNTS IN 12Z-18Z PD FAR N/. FOR SATURDAY/SATURDAY NIGHT...QUESTION TURNS TO HOW QUICKLY WILL TEMPS CLIMB ABOVE FREEZING. 03Z SREF...ENSEMBLES...KEPT SFC TEMPERATURES BELOW 32 OVER ALL ZONES THROUGH 12Z BUT BY 18Z LIFTED FREEZING LINE TO AROUND A OFK-NRN POTTAWATTAMIE COUNTY IA LINE AND TO THE SD BORDER BY 21 AND 00Z. GENERALLY FOLLOWING THAT THINKING LED TO A SPLIT OF MORNING GRIDS TO MENTION RAIN AS PREVAILING PCPN TYPE S OF PLATTE RIVER AFT 15Z AND FROM OLU-HNR IN 18Z-21Z PD WITH RAIN ALONG AND S OF THOSE AREAS. ALSO ADJUSTED HIGHS UP INTO THE MID/UPPER 40 RANGE FAR SRN NEBR ZONES AND LOW/MID 40S OVR FAR SRN IA ZONES AS EVEN ECMWF/CANADIAN GEM BRING WEDGE OF VERY WARM 850 MB AIR INTO SERN CWA BY 00Z SUN. AGAIN WILL BE ADJUSTING HRLY GRIDS TO REFLECT THIS OCCURRING CLOSER TO 00Z INSTEAD OF NORMAL DIURNAL TRENDS. WITH THE STRONG AFOREMENTIONED 850 MB JET...WOULD NOT BE SURPRISED IF TEMPS ARE EVEN WARMER THAN THAT FAR S. BOTH NAM AND GFS FORECAST STRONG MID LVL DRY AIR AT AND ABOVE 700 MB PUNCHING INTO THE SYSTEM AS FAR NE AS THE OMAHA AREA BY 18Z...SHOWN NICELY ON CROSS SECTIONS. THIS COULD SHUT MUCH OF THE PCPN DOWN TO EITHER LGT R- OR DRIZZLE...PSBLY STILL FREEZING FAR N...LATER IN THE AFTN INTO THE EVENING. THIS WILL NEED MONITORING IN LATER FORECASTS IF TRENDS PERSIST...BUT KEPT MEASURABLE POPS QUITE HIGH YET IN 18Z-06Z PD...ALTHOUGH DID START TO MENTION FREEZING DRIZZLE SOME SECTIONS AFT 06Z. BOOSTED POPS SLIGHTLY THOUGH SAT NGT INTO SUN AM AS STILL SOME DECENT FORCING POSSIBLE AS MAIN TROUGH SWINGS ACROSS. PROBABLE STRATO CU BEHIND SYSTEM ON SUNDAY COULD LIMIT HEATING...SPCLY NRN ZONES AND TRIMMED BACK HIGHS SOME. AS STATED EARLIER...LTL/NO CHANGES MADE TO EXTENDED...MAINLY TO THE PD BEYOND TUE. ECMWF/GFS BOTH LEANED TOWARD MILDER TEMPS MONDAY AND BOOSTED MOST AREAS. SOME QUESTION TUE AS ECMWF PUSHES BACKDOOR COOL FRONT INTO THE CWA WHILE 00Z GFS CONTD QUITE WARM. COMPROMISED A BIT AND BUMPED UP SWRN/CNTRL ZONES A FEW DEGREES. ALSO BOTH 00Z GFS/ECMWF SUGGESTED POPS MAY NEED INTRODUCING BY NEXT THURSDAY AS A DECENT TROUGH CROSSES AREA. AVIATION... NIL AVN CONCERNS FOR ALL TAF SITE WITH VFR CONDS EXPECTED TO PREVAIL THRU AT LEAST 01/00Z. AT THAT TIME...SFC WINDS SHIFT FM NORTH TO E/SE WITH WARM FRONT PASSAGE...POSSIBLY CAUSING MOD-SVR TURB/LLWS TWD 01/06Z. LOW CONFIDENCE REGARDING LLWS AT THIS POINT THUS NO MENTION IN TAFS FOR NOW. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR NEZ011-012-015>018-030>034-042>045-050>053-065>068-078- 088>093. IA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR IAZ043-055-056-069-079-080-090-091. && $$ DEWALD ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 1137 AM CST FRI NOV 30 2007 .AVIATION...18Z TAF. MAIN CONCERN WILL BE CHANCES FOR FREEZING PRECIPITATION LATE TONIGHT AND SATURDAY MORNING. FREEZING RAIN AND SLEET ARE EXPECTED TO MOVE INTO THE AREA LATE TONIGHT. BY MORNING THE SLEET WILL COME TO AN END BUT FREEZING RAIN WILL CONTINUE THROUGH THE MORNING. WINDS ARE ALSO EXPECTED TO INCREASE LATE TONIGHT AND TOMORROW AND CEILINGS WILL BE IFR OR LIFR IN THE MORNING. && .PREV DISCUSSION... /ISSUED 339 AM CST FRI NOV 30 2007/ DISCUSSION...RIGHT UP FRONT...THE WINTER STORM WATCH WILL CONTINUE AS IS. THERE IS THE POTENTIAL FOR SIGNIFICANT ICING... IN EXCESS OF ONE QUARTER FOR SOME PARTS OF THE NORTHEAST CWFA. THE SOUTHERN/WESTERN PARTS OF THE CWFA WILL EXPERIENCE ICE...BUT LIKELY ADVISORY LEVEL AMOUNTS. AT THIS POINT...THE WIDESPREAD COVERAGE OF THE WINTER STORM WATCH GETS THE WORD OUT AND EVEN AN UPGRADE ON THE DAYSHIFT WILL GIVE 8 TO 12+ HOURS OF LEAD TIME...AND HOPEFULLY GIVE THE BEST DEPICTION OF THE POTENTIAL SIGNIFICANT ICE EVENT. RIGHT NOW...ARCTIC LIKE AIRMASS HAS SETTLED INTO NEBRASKA BEHIND SURGING COLD FRONT. TEMPERATURES ARE NOW SOLIDLY IN THE TEENS OVER MUCH OF SOUTH CENTRAL NEBRASKA...AND DROPPING THROUGH THE 20S IN KANSAS. BELIEVE THE 00Z MODEL RUNS DID NOT HAVE A GOOD HANDLE ON THE STRENGTH OF THIS COLD AIR...WITH 1032MB SURFACE PRESSURES INTO NORTHERN NEBRASKA. CLOUDS ALSO NOW SLIDING OVER THE CWFA. WINDS PROGGED TO TURN NORTHEAST/EAST TODAY AS WELL. THOSE TWO FACTORS DON/T SUPPORT MUCH WARMING...AND HAVE LOWERED TODAY/S HIGH TEMPS. THAT ALSO MEANS THE COLD AIR WILL BE SLOWER TO DISLODGE TONIGHT. THE MAIN SHOW IS TONIGHT. OBVIOUSLY TEMPERATURES AND SUBSEQUENT PRECIPITATION PHASE IS PARAMOUNT...BUT THE MOISTURE TRANSPORT ASSOCIATED WITH MASSIVE WARM ADVECTION IS ANOTHER BIG POINT. PRECIPITABLE WATER VALUES ARE UP TO 4+ STANDARD DEVIATION ABOVE NORMAL FOR EARLY DECEMBER...AND ABOVE 1 INCH. SUCH ANOMALOUS INGREDIENTS CAN RESULT IN ANOMALOUS RESULTS (SEE ICE STORM 2006). FORECAST SOUNDINGS SUGGEST THE FOLLOWING...ROUGHLY THE SOUTHERN 1/4 OF THE CWFA WILL START AS FREEZING RAIN AND THEN TURN TO RAIN SHORTLY AFTER 12Z SATURDAY. THE NEXT QUARTER OF THE CWFA WILL HOLD ONTO THE FREEZING RAIN A LITTLE LONGER BEFORE TURNING TO RAIN. THE NORTHERN HALF OF THE CWFA WILL LIKELY CATCH SOME SLEET AS WARM LAYER DOESN/T REALLY GET DEEP ENOUGH TIL MID TO LATE SATURDAY MORNING. THE FAR NORTHERN CWFA COULD VERY WELL START AS SLEET...THEN MIX WITH FREEZING RAIN...AND THEN GO TO FREEZING RAIN IN THE AFTERNOON. THIS FAVORS A COOLER RUC AND NAME SOLUTION. GFS IS TOO FAR NORTH. THE PROBLEM IS ALL THE MODELS SHOW QPF IN EXCESS OF 0.25 INCHES...CLOSER TO 0.50 INCHES... MUCH OF WHICH WILL FALL AS SLEET OR FREEZING RAIN. THIS WOULD BE MOST LIKELY IN THE NORTHEAST CWFA. SUCH AMOUNTS OF ICE OF WOULD NOT ONLY HALT TRAVEL NORTH AND EAST OF GRAND ISLAND...BUT COULD RESULT IN DAMAGE TO TREES AND POWER LINES/POLES. ABOUT THE ONLY PROMISING NEWS WITH THIS EVENT IS IT SHOULD BE QUICK HITTING...ROUGHLY FROM AROUND MIDNIGHT FRIDAY NIGHT...TO MID AFTERNOON SATURDAY. THE HEAVIEST PRECIPITATION LOOK LIKELY FROM ABOUT 4 AM SATURDAY THROUGH NOONISH...WITH THE PRECIPITATION ENDING FROM SOUTHWEST TO NORTHEAST. ANOTHER INTERESTING POINT...IS WE ARE FORECASTING HUGE WARMING...INTO THE 50S...IN THE SOUTHEAST CWFA. THAT WILL RAPIDLY MELT ANY ICE ACCUMULATION...AND THAT TOO COULD LIMIT ICE IMPACTS IN THE SOUTHERN CWFA. AGAIN...STILL THE POTENTIAL FOR A MAJOR ICE EVENT OVER THE CWFA LATE FRIDAY NIGHT AND DURING THE DAY SATURDAY. THE HEAVIEST ICE AMOUNTS LIKELY NORTH AND EAST OF A LINE FROM LOUP CITY...TO HASTINGS...TO GENEVA. ICE ACCUMULATION IN THIS AREA COULD EXCEED ONE QUARTER INCH. LESSER AMOUNTS OF ICE...THROUGH STILL SIGNIFICANT...WILL OCCUR OVER THE SOUTHERN AND WESTERN CWFA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WATCH FROM 9 PM CST THIS EVENING THROUGH SATURDAY EVENING FOR NEZ039>041-046>049-060>064-072>077-082>087. KS...WINTER STORM WATCH FROM 9 PM CST THIS EVENING THROUGH SATURDAY MORNING FOR KSZ005>007-017>019. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 609 AM CST FRI NOV 30 2007 .AVIATION...12Z TAF. NORTH TO NORTHEAST WINDS TO START THE PERIOD WILL GRADUALLY VEER THROUGH THE DAY...BECOMING SOUTHEASTERLY BY AFTERNOON. HIGH CLOUDS WILL GRADUALLY THICKEN AND LOWER THROUGH THE DAY...BUT CEILINGS WILL STAY AT 15K FEET OR ABOVE THROUGH SUNSET. CEILINGS WILL THEN LOWER THIS EVENING AS A WINTER STORM DRAWS NEARER. A MIX OF FREEZING RAIN AND SLEET WILL START TO FALL AFTER MIDNIGHT...WITH CEILINGS AND VISIBILITIES DROPPING INTO THE IFR RANGE OR LOWER. && .PREV DISCUSSION... /ISSUED 339 AM CST FRI NOV 30 2007/ DISCUSSION...RIGHT UP FRONT...THE WINTER STORM WATCH WILL CONTINUE AS IS. THERE IS THE POTENTIAL FOR SIGNIFICANT ICING... IN EXCESS OF ONE QUARTER FOR SOME PARTS OF THE NORTHEAST CWFA. THE SOUTHERN/WESTERN PARTS OF THE CWFA WILL EXPERIENCE ICE...BUT LIKELY ADVISORY LEVEL AMOUNTS. AT THIS POINT...THE WIDESPREAD COVERAGE OF THE WINTER STORM WATCH GETS THE WORD OUT AND EVEN AN UPGRADE ON THE DAYSHIFT WILL GIVE 8 TO 12+ HOURS OF LEAD TIME...AND HOPEFULLY GIVE THE BEST DEPICTION OF THE POTENTIAL SIGNIFICANT ICE EVENT. RIGHT NOW...ARCTIC LIKE AIRMASS HAS SETTLED INTO NEBRASKA BEHIND SURGING COLD FRONT. TEMPERATURES ARE NOW SOLIDLY IN THE TEENS OVER MUCH OF SOUTH CENTRAL NEBRASKA...AND DROPPING THROUGH THE 20S IN KANSAS. BELIEVE THE 00Z MODEL RUNS DID NOT HAVE A GOOD HANDLE ON THE STRENGTH OF THIS COLD AIR...WITH 1032MB SURFACE PRESSURES INTO NORTHERN NEBRASKA. CLOUDS ALSO NOW SLIDING OVER THE CWFA. WINDS PROGGED TO TURN NORTHEAST/EAST TODAY AS WELL. THOSE TWO FACTORS DON/T SUPPORT MUCH WARMING...AND HAVE LOWERED TODAY/S HIGH TEMPS. THAT ALSO MEANS THE COLD AIR WILL BE SLOWER TO DISLODGE TONIGHT. THE MAIN SHOW IS TONIGHT. OBVIOUSLY TEMPERATURES AND SUBSEQUENT PRECIPITATION PHASE IS PARAMOUNT...BUT THE MOISTURE TRANSPORT ASSOCIATED WITH MASSIVE WARM ADVECTION IS ANOTHER BIG POINT. PRECIPITABLE WATER VALUES ARE UP TO 4+ STANDARD DEVIATION ABOVE NORMAL FOR EARLY DECEMBER...AND ABOVE 1 INCH. SUCH ANOMALOUS INGREDIENTS CAN RESULT IN ANOMALOUS RESULTS (SEE ICE STORM 2006). FORECAST SOUNDINGS SUGGEST THE FOLLOWING...ROUGHLY THE SOUTHERN 1/4 OF THE CWFA WILL START AS FREEZING RAIN AND THEN TURN TO RAIN SHORTLY AFTER 12Z SATURDAY. THE NEXT QUARTER OF THE CWFA WILL HOLD ONTO THE FREEZING RAIN A LITTLE LONGER BEFORE TURNING TO RAIN. THE NORTHERN HALF OF THE CWFA WILL LIKELY CATCH SOME SLEET AS WARM LAYER DOESN/T REALLY GET DEEP ENOUGH TIL MID TO LATE SATURDAY MORNING. THE FAR NORTHERN CWFA COULD VERY WELL START AS SLEET...THEN MIX WITH FREEZING RAIN...AND THEN GO TO FREEZING RAIN IN THE AFTERNOON. THIS FAVORS A COOLER RUC AND NAME SOLUTION. GFS IS TOO FAR NORTH. THE PROBLEM IS ALL THE MODELS SHOW QPF IN EXCESS OF 0.25 INCHES...CLOSER TO 0.50 INCHES... MUCH OF WHICH WILL FALL AS SLEET OR FREEZING RAIN. THIS WOULD BE MOST LIKELY IN THE NORTHEAST CWFA. SUCH AMOUNTS OF ICE OF WOULD NOT ONLY HALT TRAVEL NORTH AND EAST OF GRAND ISLAND...BUT COULD RESULT IN DAMAGE TO TREES AND POWER LINES/POLES. ABOUT THE ONLY PROMISING NEWS WITH THIS EVENT IS IT SHOULD BE QUICK HITTING...ROUGHLY FROM AROUND MIDNIGHT FRIDAY NIGHT...TO MID AFTERNOON SATURDAY. THE HEAVIEST PRECIPITATION LOOK LIKELY FROM ABOUT 4 AM SATURDAY THROUGH NOONISH...WITH THE PRECIPITATION ENDING FROM SOUTHWEST TO NORTHEAST. ANOTHER INTERESTING POINT...IS WE ARE FORECASTING HUGE WARMING...INTO THE 50S...IN THE SOUTHEAST CWFA. THAT WILL RAPIDLY MELT ANY ICE ACCUMULATION...AND THAT TOO COULD LIMIT ICE IMPACTS IN THE SOUTHERN CWFA. AGAIN...STILL THE POTENTIAL FOR A MAJOR ICE EVENT OVER THE CWFA LATE FRIDAY NIGHT AND DURING THE DAY SATURDAY. THE HEAVIEST ICE AMOUNTS LIKELY NORTH AND EAST OF A LINE FROM LOUP CITY...TO HASTINGS...TO GENEVA. ICE ACCUMULATION IN THIS AREA COULD EXCEED ONE QUARTER INCH. LESSER AMOUNTS OF ICE...THROUGH STILL SIGNIFICANT...WILL OCCUR OVER THE SOUTHERN AND WESTERN CWFA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY EVENING FOR NEZ039>041-046>049-060>064-072>077-082>087. KS...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR KSZ005>007-017>019. && $$ AVIATION...KB PREV DISCUSSION...MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 350 AM CST FRI NOV 30 2007 .DISCUSSION... OBVIOUSLY PRECIPITATION TYPE/AMOUNTS WITH SYSTEM LATE TONIGHT AND SATURDAY IS THE MAIN FORECAST CONCERN AND FOCUS...AND LITTLE/NO CHANGES WERE MADE IN THE EXTENDED. SINCE MAIN EVENT WILL PROBABLY BE IN 09Z-00Z PERIOD ON SATURDAY...NO UPGRADE YET TO WATCH WILL BE MADE. OVERALL QPF AMOUNTS FOR THE EVENT COULD EASILY SURPASS 0.5 INCHES...AND POSSIBLY REACH 1 INCH IN SPOTS AS PRECIPITABLE WATER VALUES ARE FORECAST TO CROSS 1 INCH. IT WAS NOTED ON LAST NIGHTS UA ANLYS THAT THE 850 MB DWPT AT TUCSON WAS 11 DEG C SO NOT ONLY WILL THIS SYSTEM TAP GULF MOISTURE...IT LOOKS LIKE IT WILL BE BRINGING AMPLE PACIFIC MOISTURE WITH IT AS WELL. THUS...IN THE SHORTER TERM TODAY AND TONIGHT. MODIFIED ARCTIC AIRMASS HAS BROUGHT SHALLOW COLD/DRY AIR ACROSS THE CWA WHICH WAS NOT HANDLED WELL BY THE 00Z GFS AND EVEN 06Z NAM...BOTH OF WHICH WERE TOO WARM. LATEST RUC HANDLED IT BETTER AND IT WAS ABOUT 5 DEGREES COOLER BY 18Z. HRLY TEMPS/MAX TEMPS WILL BE ADJUSTED THAT WAY...WHICH WILL GENERALLY BE A DOWNWARD ADJUSTMENT. FOR TONIGHT...VERY STRONG WARM ADVCTN DEVELOPS WITH NAM/ECMWF FORECASTING AN 850 MB JET OF 40-45 KTS ACROSS THE CWA BY 12Z SAT. IN FACT...BOTH OF THOSE MODELS INCREASED THIS JET INTO THE 70-75 KT RANGE DURING THE DAY SAT...WHICH IS QUITE IMPRESSIVE. BASED ON FORECAST SOUNDINGS FREEZING RAIN OR A FREEZING RAIN/SLEET MIX IS THE MOST LIKELY OUTCOME FOR MUCH OF THE PCPN UNTIL TEMPS CAN WARM ABOVE FREEZING...WHICH LOOKS LIKE IT WON/T BE UNTIL SOMETIME SATURDAY AFT 12Z. NEEDLESS TO SAY WITH SUCH A COLD/DRY AIRMASS TO BEGIN THIS EVENT...SIGNIFICANT ICING IS POSSIBLE WITH MAIN FLY IN THE PCPN OINTMENT SO TO SPEAK BEING HOW MUCH SLEET WILL FALL OR MIX IN. ALTHOUGH 1000-500 MB THICKNESSES FORECAST FOR TONIGHT WERE A BIT TOO WARM FOR SNOW...FORECAST SOUNDINGS DO SUPPORT A CHC OF IT TO BEGIN THE EVENT...ALTHOUGH QUITE BRIEF SRN HALF OF THE CWA. WL MENTION SOME 1/2-1 INCH SNOW ACCUMULATIONS NORTH TNGT TAPERING OFF TO ONE/TWO TENTHS ALONG PLATTE RIVER AND NOTHING S OF THERE INCLUDING 4 SW IA COUNTIES. /DID ALSO LINGER SOME 1-2 INCH ADDITIONAL AMOUNTS IN 12Z-18Z PD FAR N/. FOR SATURDAY/SATURDAY NIGHT...QUESTION TURNS TO HOW QUICKLY WILL TEMPS CLIMB ABOVE FREEZING. 03Z SREF...ENSEMBLES...KEPT SFC TEMPERATURES BELOW 32 OVER ALL ZONES THROUGH 12Z BUT BY 18Z LIFTED FREEZING LINE TO AROUND A OFK-NRN POTTAWATTAMIE COUNTY IA LINE AND TO THE SD BORDER BY 21 AND 00Z. GENERALLY FOLLOWING THAT THINKING LED TO A SPLIT OF MORNING GRIDS TO MENTION RAIN AS PREVAILING PCPN TYPE S OF PLATTE RIVER AFT 15Z AND FROM OLU-HNR IN 18Z-21Z PD WITH RAIN ALONG AND S OF THOSE AREAS. ALSO ADJUSTED HIGHS UP INTO THE MID/UPPER 40 RANGE FAR SRN NEBR ZONES AND LOW/MID 40S OVR FAR SRN IA ZONES AS EVEN ECMWF/CANADIAN GEM BRING WEDGE OF VERY WARM 850 MB AIR INTO SERN CWA BY 00Z SUN. AGAIN WILL BE ADJUSTING HRLY GRIDS TO REFLECT THIS OCCURRING CLOSER TO 00Z INSTEAD OF NORMAL DIURNAL TRENDS. WITH THE STRONG AFOREMENTIONED 850 MB JET...WOULD NOT BE SURPRISED IF TEMPS ARE EVEN WARMER THAN THAT FAR S. BOTH NAM AND GFS FORECAST STRONG MID LVL DRY AIR AT AND ABOVE 700 MB PUNCHING INTO THE SYSTEM AS FAR NE AS THE OMAHA AREA BY 18Z...SHOWN NICELY ON CROSS SECTIONS. THIS COULD SHUT MUCH OF THE PCPN DOWN TO EITHER LGT R- OR DRIZZLE...PSBLY STILL FREEZING FAR N...LATER IN THE AFTN INTO THE EVENING. THIS WILL NEED MONITORING IN LATER FORECASTS IF TRENDS PERSIST...BUT KEPT MEASURABLE POPS QUITE HIGH YET IN 18Z-06Z PD...ALTHOUGH DID START TO MENTION FREEZING DRIZZLE SOME SECTIONS AFT 06Z. BOOSTED POPS SLIGHTLY THOUGH SAT NGT INTO SUN AM AS STILL SOME DECENT FORCING POSSIBLE AS MAIN TROUGH SWINGS ACROSS. PROBABLE STRATO CU BEHIND SYSTEM ON SUNDAY COULD LIMIT HEATING...SPCLY NRN ZONES AND TRIMMED BACK HIGHS SOME. AS STATED EARLIER...LTL/NO CHANGES MADE TO EXTENDED...MAINLY TO THE PD BEYOND TUE. ECMWF/GFS BOTH LEANED TOWARD MILDER TEMPS MONDAY AND BOOSTED MOST AREAS. SOME QUESTION TUE AS ECMWF PUSHES BACKDOOR COOL FRONT INTO THE CWA WHILE 00Z GFS CONTD QUITE WARM. COMPROMISED A BIT AND BUMPED UP SWRN/CNTRL ZONES A FEW DEGREES. ALSO BOTH 00Z GFS/ECMWF SUGGESTED POPS MAY NEED INTRODUCING BY NEXT THURSDAY AS A DECENT TROUGH CROSSES AREA. && .AVIATION... NIL AVN CONCERNS FOR ALL TAF SITE WITH VFR CONDS EXPECTED TO PREVAIL THRU AT LEAST 01/00Z. AT THAT TIME...SFC WINDS SHIFT FM NORTH TO E/SE WITH WARM FRONT PASSAGE...POSSIBLY CAUSING MOD-SVR TURB/LLWS TWD 01/06Z. LOW CONFIDENCE REGARDING LLWS AT THIS POINT THUS NO MENTION IN TAFS FOR NOW. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR NEZ011-012-015>018-030>034-042>045-050>053-065>068-078- 088>093. IA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR IAZ043-055-056-069-079-080-090-091. && $$ CHERMOK/DEE ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 339 AM CST FRI NOV 30 2007 .DISCUSSION...RIGHT UP FRONT...THE WINTER STORM WATCH WILL CONTINUE AS IS. THERE IS THE POTENTIAL FOR SIGNIFICANT ICING... IN EXCESS OF ONE QUARTER FOR SOME PARTS OF THE NORTHEAST CWFA. THE SOUTHERN/WESTERN PARTS OF THE CWFA WILL EXPERIENCE ICE...BUT LIKELY ADVISORY LEVEL AMOUNTS. AT THIS POINT...THE WIDESPREAD COVERAGE OF THE WINTER STORM WATCH GETS THE WORD OUT AND EVEN AN UPGRADE ON THE DAYSHIFT WILL GIVE 8 TO 12+ HOURS OF LEAD TIME...AND HOPEFULLY GIVE THE BEST DEPICTION OF THE POTENTIAL SIGNIFICANT ICE EVENT. RIGHT NOW...ARCTIC LIKE AIRMASS HAS SETTLED INTO NEBRASKA BEHIND SURGING COLD FRONT. TEMPERATURES ARE NOW SOLIDLY IN THE TEENS OVER MUCH OF SOUTH CENTRAL NEBRASKA...AND DROPPING THROUGH THE 20S IN KANSAS. BELIEVE THE 00Z MODEL RUNS DID NOT HAVE A GOOD HANDLE ON THE STRENGTH OF THIS COLD AIR...WITH 1032MB SURFACE PRESSURES INTO NORTHERN NEBRASKA. CLOUDS ALSO NOW SLIDING OVER THE CWFA. WINDS PROGGED TO TURN NORTHEAST/EAST TODAY AS WELL. THOSE TWO FACTORS DON/T SUPPORT MUCH WARMING...AND HAVE LOWERED TODAY/S HIGH TEMPS. THAT ALSO MEANS THE COLD AIR WILL BE SLOWER TO DISLODGE TONIGHT. THE MAIN SHOW IS TONIGHT. OBVIOUSLY TEMPERATURES AND SUBSEQUENT PRECIPITATION PHASE IS PARAMOUNT...BUT THE MOISTURE TRANSPORT ASSOCIATED WITH MASSIVE WARM ADVECTION IS ANOTHER BIG POINT. PRECIPITABLE WATER VALUES ARE UP TO 4+ STANDARD DEVIATION ABOVE NORMAL FOR EARLY DECEMBER...AND ABOVE 1 INCH. SUCH ANOMALOUS INGREDIENTS CAN RESULT IN ANOMALOUS RESULTS (SEE ICT STORM 2006). FORECAST SOUNDINGS SUGGEST THE FOLLOWING...ROUGHLY THE SOUTHERN 1/4 OF THE CWFA WILL START AS FREEZING RAIN AND THEN TURN TO RAIN SHORTLY AFTER 12Z SATURDAY. THE NEXT QUARTER OF THE CWFA WILL HOLD ONTO THE FREEZING RAIN A LITTLE LONGER BEFORE TURNING TO RAIN. THE NORTHERN HALF OF THE CWFA WILL LIKELY CATCH SOME SLEET AS WARM LAYER DOESN/T REALLY GET DEEP ENOUGH TIL MID TO LATE SATURDAY MORNING. THE FAR NORTHERN CWFA COULD VERY WELL START AS SLEET...THEN MIX WITH FREEZING RAIN...AND THEN GO TO FREEZING RAIN IN THE AFTERNOON. THIS FAVORS A COOLER RUC AND NAME SOLUTION. GFS IS TOO FAR NORTH. THE PROBLEM IS ALL THE MODELS SHOW QPF IN EXCESS OF 0.25 INCHES...CLOSER TO 0.50 INCHES... MUCH OF WHICH WILL FALL AS SLEET OR FREEZING RAIN. THIS WOULD BE MOST LIKELY IN THE NORTHEAST CWFA. SUCH AMOUNTS OF ICE OF WOULD NOT ONLY HALT TRAVEL NORTH AND EAST OF GRAND ISLAND...BUT COULD RESULT IN DAMAGE TO TREES AND POWER LINES/POLES. ABOUT THE ONLY PROMISING NEWS WITH THIS EVENT IS IT SHOULD BE QUICK HITTING...ROUGHLY FROM AROUND MIDNIGHT FRIDAY NIGHT...TO MID AFTERNOON SATURDAY. THE HEAVIEST PRECIPITATION LOOK LIKELY FROM ABOUT 4 AM SATURDAY THROUGH NOONISH...WITH THE PRECIPITATION ENDING FROM SOUTHWEST TO NORTHEAST. ANOTHER INTERESTING POINT...IS WE ARE FORECASTING HUGE WARMING...INTO THE 50S...IN THE SOUTHEAST CWFA. THAT WILL RAPIDLY MELT ANY ICE ACCUMULATION...AND THAT TOO COULD LIMIT ICE IMPACTS IN THE SOUTHERN CWFA. AGAIN...STILL THE POTENTIAL FOR A MAJOR ICE EVENT OVER THE CWFA LATE FRIDAY NIGHT AND DURING THE DAY SATURDAY. THE HEAVIEST ICE AMOUNTS LIKELY NORTH AND EAST OF A LINE FROM LOUP CITY...TO HASTINGS...TO GENEVA. ICE ACCUMULATION IN THIS AREA COULD EXCEED ONE QUARTER INCH. LESSER AMOUNTS OF ICE...THROUGH STILL SIGNIFICANT...WILL OCCUR OVER THE SOUTHERN AND WESTERN CWFA. && .PREV DISCUSSION... /ISSUED 1159 PM CST THU NOV 29 2007/ AVIATION...06Z TAF. COLD FRONT HAS PASSED THROUGH THE TERMINAL LOCATION OVER THE PAST COUPLE HOURS...AND WILL CONTINUE ITS PUSH SOUTH. NORTHERLY WINDS IN THE 15 TO 20 KT RANGE WILL CONTINUE FOR THE NEXT SEVERAL HOURS IN THE TIGHTENED GRADIENT BEHIND THE FRONT. SATELLITE IMAGERY SHOWS A NARROW BROKEN BAND OF LOW CLOUDS IN NORTHERN NEBRASKA AND MODELS SUGGEST THIS MAY MAKE IT SOUTH. HAVE INCLUDED A TEMPO GROUP TO ACCOUNT FOR THIS BUT THINK ANY LOWER CLOUDS WILL BE FEW OR SCT AT BEST...AND HAVE KEPT A CIG OUT OF THE FORECAST. WINDS WILL GRADUALLY VEER THROUGH THE DAY AS THE SURFACE HIGH PROGRESSES SOUTHEAST INTO THE UPPER MIDWEST BY EVENING. HIGH CLOUDS WILL THICKEN THROUGH THE DAY AHEAD OF AN APPROACHING WINTER STORM. WILL SEE A DECK OF MID CLOUDS MOVING INTO THE AREA BY SUNSET WITH CIGS THEN DROPPING TO 4-5K FEET NEAR THE END OF THE PERIOD. PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL AFTER 06Z SATURDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY EVENING FOR NEZ039>041-046>049-060>064-072>077-082>087. KS...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR KSZ005>007-017>019. && $$ MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1002 PM EST FRI NOV 30 2007 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA THIS EVENING, BRINGING ANOTHER SHOT OF COLD AIR INTO THE REGION. THIS IN TURN, WILL SET OFF ANOTHER ROUND OF LAKE EFFECT SNOW SHOWERS, PRIMARILY SOUTHEAST OF LAKE ONTARIO OVERNIGHT AND EARLY SATURDAY. SATURDAY NIGHT, A POWERFUL WINTER STORM WILL MOVE EAST THROUGH THE OHIO VALLEY. THIS STORM WILL BRING SNOW TO THE REGION ON SUNDAY, THEN A MIXED BAG OF PRECIPITATION SUNDAY AFTERNOON THROUGH SUNDAY NIGHT, BEFORE CHANGING BACK TO SNOW LATE SUNDAY NIGHT AND MONDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... FORECAST ON TRACK WITH THE COLD FRONT FROM ELMIRA TO ONEONTA. SOME SNOW SHOWERS WITH IT BUT MOST OF INTENSITY HAS DIMINISHED FROM EARLIER. BEHIND IT A BAND OF LAKE EFFECT HAS ALREADY SET UP IN ONEIDA COUNTY. THIS WILL BECOME MORE INTENSE THEN DIMINISH LATE TONIGHT AS THE BAND SHIFTS SOUTH AND WEAKENS. WILL CONTINUE WITH ADVISORY FOR ONEIDA WITH 3 TO 6 INCHES. 18Z NAM AND 00Z RUC AS WELL AS LOCAL MODELS SUPPORT SCENARIO. AS ACTIVITY DROPS SOUTH NRN SUSQU REGION AND NRN FINGER LAKES COULD GET 1 TO 2 INCHES POSSIBLY 3. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... SATURDAY...AFTER LINGERING SNOW SHOWERS/FLURRIES DISSIPATE BY MID MORNING SFC HIGH PRES OVER SOUTHERN ONTARIO WILL BUILD DOWN OVER AREA. EXPECT PARTLY TO MOSTLY SUNNY SKIES WITH MAX TEMPS BTW 5 TO 10 DEGREES BELOW NORMAL. SATURDAY NIGHT...SFC HIGH PRES OVER SRN ONTARIO PUSHES DUE NORTH AS SFC LOW MOVES INTO SRN WISC BY 12Z SUNDAY. FOR HALF THE NIGHT CONDITIONS WILL BE IDEAL FOR RADITIONAL COOLING THEN MID/HIGH CLOUDS WILL SPREAD ACROSS FA. INITIAL SURGE OF ISENTROPIC LIFT WEAKENS SIGNIFICANTLY DUE TO HIGH PRES INTERACTION. WENT LIKELY POPS LATE FOE FAR WESTERN ZONES INTO THE WYOMING VALLEY. P-TYPE WILL BE SNOW. SUNDAY...AFTER INITIAL SHOT OF WAA FORCING MOVES ACROSS REGION IN A WEAKENED STATE LIFT NOT VERY EXCITING UNTIL SUNDAY EVENING. MODELS IN FAIR AGREEMENT WITH STORM EVOLUTION BUT DO VARY SIGNIFICANTLY WITH MID LEVEL WARM WEDGE. NAM IS THE COLDEST MODEL WITH ECMWF THE WARMEST AND GFS IN BETWEEN. EXPECT PRECIP TO MIX WITH OR CHANGE TO SLEET BY SUNDAY AFTERNOON FROM I81 WEST. ANY SNOW ACCUM THROUGH SUNDAY AFTERNOON WILL BE 3 INCHES OR LESS. PRECIP MAY NOT REACH FAR EASTERN ZONES UNTIL MID AFTERNOON SUNDAY DUE WEAK LIFT AND SFC HIGH PRES STILL NOSING DOWN INTO EASTERN NY. SUNDAY NIGHT...A VERY DIFFICULT FORECAST WITH PRECIP TYPE AND AMOUNT OF QPF DUE TO COASTAL TRANSFER. WITH WARM MID LEVELS EXPECT MIXED PRECIP ALL AREAS WITH THE POTENTIAL OF SIGNIFICANT SNOWFALL OR ICING POSSIBLE ACROSS THE WESTERN CATSKILLS/WESTERN MOHAWK VALLEY. THIS IS THE LOCATION WHERE A WINTER STORM WATCH MAY BE NEEDED AS REST OF CWA WILL NOT REACH EITHER THE SNOW OR ICING ACCUM TO JUSTIFY A WARNING. HERE AN ADVISORY WILL LIKELY BE POSTED. SINCE PRECIP MAY NOT START UNTIL SUNDAY AFTERNOON ACROSS ERN CWA THERE IS ENOUGH TIME TO ISSUE WATCH WITH ALL THIS UNCERTAINTY. MONDAY...COASTAL LOW BECOMES PRIMARY FEATURE WITH STRONG MID LEVEL COOLING CHANGING ALL PRECIP BACK TO SNOW SHOWERS BY MID MORNING. ADDI TONAL SNOW ACCUM POSSIBLY ESP WESTERN CATSKILLS THROUGH MOHAWK VALLEY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS THE SYNOPTIC-SCALE STORM WINDS UP ALONG THE NEW ENGLAND COAST WRAP-AROUND / LAKE ENHANCED SNOW SHOWERS WILL PERSIST THROUGH TUESDAY. ANOTHER STORM SYSTEM WILL MAKE A RUN AT THE EASTERN STATES WEDNESDAY INTO THURSDAY...WITH A CHANCE OF SNOW INDICATED IN THE FORECAST. BEHIND THIS SYSTEM...MORE LAKE-EFFECT SNOW SHOWERS FOR THE LATTER PART OF THE WEEK...AS A REINFORCING SHOT OF COLD AIR COMES IN FROM THE NORTHWEST. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... COLD FNT CUTTING THRU THE FCST AREA THIS EVE. BRIEF IFR CONDS IN SNOW SHWRS ARE PSBL DURING THE PASSAGE OF THE FNT...WITH GUSTY WINDS. BHD THE FNT MVFR OR EVEN IFR CONDS WILL DVLP AGAIN AS LAKE EFFECT SNOWS DVLP AFT 03ZAND BRNGS SNOW SHWRS TO RME/SYR/ITH AND BGM. ELM AND AVP SHD REMAIN VFR THRU THE NGT...EVEN WITH SCT SNOW SHWRS. OUTLOOK...SATURDAY NIGHT TO WEDNESDAY... LIGHT SNOW MAY DEVELOP LATE SATURDAY NIGHT INTO EARLY SUNDAY...BRINGING RESTRICTIONS. MIXED RAIN...FREEZING RAIN...AND SLEET ON SUNDAY NIGHT...GOING BACK TO SNOW SHOWERS BY MONDAY...WILL BRING ADDITIONAL RESTRICTIONS. SCATTERED LAKE- ENHANCED SNOW SHOWERS FROM TUESDAY INTO WEDNESDAY WILL PERHAPS KEEP RESTRICTIONS GOING OVER UPSTATE NY...WITH POSSIBLE IMPROVEMENT TO VFR ACROSS NORTHEAST PA. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SATURDAY FOR NYZ009- 037. && $$ SYNOPSIS...RRM NEAR TERM...RRM/TAC SHORT TERM...RRM LONG TERM...MLJ AVIATION...DGM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 106 PM EST THU NOV 29 2007 .SYNOPSIS... A COLD FRONT WILL MOVE EAST OF THE REGION BY EARLY AFTERNOON...BRINGING AN END TO MIXED RAIN AND SNOW SHOWERS FOR THE REST OF TODAY. AN INTENSE BAND OF LAKE EFFECT SNOW WILL DROP INTO THE TUG HILL PLATEAU REGION TONIGHT WITH SIGNIFICANT SNOW ACCUMULATION EXPECTED THROUGH EARLY FRIDAY. ANOTHER WEAK FRONTAL SYSTEM WILL CROSS THE AREA FRIDAY AFTERNOON WITH MORE RAIN OR SNOW SHOWERS. HIGH PRESSURE WILL BUILD OVER THE AREA ON SATURDAY WITH FAIR WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT PASSING THROUGH THE AREA WITH PRECIPITATION MOVING EAST AND DWINDLING. LLVL FLOW FOR THE REST OF THE DAY LOOKS TO ORIENT ON A SW-NE DIRECTION WITH ANY DEVELOPING LAKE EFFECT BAND ACTIVITY TO BE NORTH AND WEST OF CNY. THE LATEST RUC AND 12Z NAM MODELS ARE INDICATING THE AFTERNOON TO BE MAINLY DRY...WITH THE POSSIBLE EXCEPTION OF SOME RENEGADE SHRA/SHSN DRIFTING THROUGH THE NRN FINGER LAKES TO SRN TUG HILL. AS A RESULT...HAVE MODIFIED THE FORECAST TO ONLY MENTION LOW MEASURABLE CHANCES IN THE NORTHERN ZONES WITH DRY CONDITIONS ELSEWHERE. TEMPERATURES APPEAR TO BE ON TRACK...AND WINDS WILL BE GUSTY FROM THE SW. LAKE EFFECT BANDING WILL DEVELOP IN OUR AREA THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... GOOD LOOKING SET UP FOR LES BAND THIS EVENING THROUGH FRIDAY MORNING. EL HEIGHTS NEAR 700 MB, PLENTY OF MOISTURE, AND A STRONG FETCH OFF OF LAKE ONTARIO WILL GENERATE AN INTENSE BAND OF SNOW OVER THE TUG HILL PLATEAU. THE SNOW BAND IS FORECAST TO DIP INTO NORTHERN ONEIDA COUNTY BETWEEN 0Z AND 3Z, AND REMAIN NEARLY STEADY STATE THROUGH SUNRISE. BASED ON INSTABILITY PARAMETERS, AND ALSO -10 OMEGA EXTENDING INTO DENDRITE REGION, WE THINK THIS COULD BE A SIGNIFICANT EVENT. AT THIS POINT WILL FORECAST 6 TO 12 INCHES OF SNOW, THOUGH A FEW EVENTS IN THE LES SIMILAR SOUNDINGS DATABASE PRODUCED HIGHER AMOUNTS. I AM A LITTLE CONCERNED ABOUT THE AMT OF FORECAST SHEAR, WHICH IS HIGHER THAN PVS 24H FORECAST. ALSO NAM12 PLAN VIEW IS SLOWER TO DROP BAND INTO ONEIDA UTILIZING LOW LEVEL OMEGA FIELDS. OTHERWISE EVERYTHING LOOKS LIKE "GO" AND WE HAVE ISSUED AN LES WARNING. AN ADDITIONAL LES BAND IS PROBABLE FRIDAY NIGHT INTO EARLY SATURDAY, AS A STRONG SHORTWAVE PUNCHES THROUGH LOWER ONTARIO. THE FLOW IS A BIT MORE NORTHWESTERLY THIS TIME AROUND, PLACING THE BAND FROM ONEIDA COUNTY DOWN THROUGH ONONDAGA AND POSSIBLY THE FINGER LAKES. THE FLOW IS MORE SHEARED, AND IT SHIFTS TO A 310-320 FLOW MIDWAY THROUGH THE EVENT. SO THE ACCUMULATION POTENTIAL IS MUTED SOMEWHAT. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE SUNDAY-MONDAY FORECAST IS SLOWLY COMING INTO BETTER FOCUS...AS THE GFS AND ECMWF CONVERGE /ALMOST TO AN UNCANNY DEGREE WITH THEIR 00Z RUNS/ TO A COMMON SOLUTION ON THE IMPENDING STORMY WEATHER. ENERGY SITTING OFF OF BAJA CALIFORNIA WILL TEAM UP WITH ENERGY DIVING SOUTH ALONG THE US WEST COAST TOMORROW...AND EJECT INTO THE ROCKIES BY SATURDAY MORNING. THE GFS/ECMWF AGREE THAT LOW PRESSURE WILL DEVELOP EAST OF THE ROCKIES ON SATURDAY AND TAKE A TRACK FROM NEAR DENVER AT 12Z SATURDAY...TO SOUTHERN WISCONSIN BY 12Z SUNDAY. STRONG ISENTROPIC LIFT AHEAD OF A SURFACE WARM FRONT SHOULD GET SNOW GOING ACROSS THE CWA BY EARLY SUNDAY MORNING. THE OPERATIONAL GFS IS STILL A BIT QUICKER WITH PRECIP ONSET...BUT NOT BY MUCH...AND NOT ENOUGH TO CHANGE THE SUNDAY FORECAST. ON SUNDAY...THE SURFACE LOW WILL TURN EAST AND TRAVEL ACROSS CENTRAL MICHIGAN. THE 00Z RUNS ARE SIGNIFICANTLY WEAKER WITH THIS LOW...AND..IN CONTRAST TO YESTERDAY...HAVE A COASTAL LOW DEVELOPING NEAR NJ THAT MOVES NORTHEAST AND QUICKLY BECOMES THE DOMINANT CIRCULATION CENTER. THERE REMAINS A PUSH OF WARM AIR ALOFT INTO THE REGION DURING THE AFTERNOON SUNDAY AS THE 850 LOW MOVES NORTH OF THE AREA. THEREFORE...HAVE INTRODUCED SLEET SUNDAY AFTERNOON...AND EVEN SOME RAIN IN THE FAR WEST. THE RELATIVE STRENGTHS OF THE PRIMARY LOW AND ITS SUBSEQUENT REDEVELOPMENT WILL CERTAINLY DETERMINE HOW FAR NORTHEAST THE WARM AIR MAKES IT BEFORE THE NEW LOW TAKES OVER AND DRAWS IN MUCH COOLER AIR FROM THE NORTHWEST. HAVE PLAYED A RA/SN/IP MIX IN THE GRIDS SUNDAY NIGHT...WITH ZR NOT OUT OF THE QUESTION EITHER... ALTHOUGH IT LOOKS LIKE ANY ZR WOULD BE SHORT LIVED. THERE REMAINS THE POTENTIAL FOR OUR NORTHERNMOST ZONES TO NEVER CHANGEOVER TO PLAIN RAIN. HOWEVER...FURTHER SOUTH...AT LEAST SOME RAIN LOOKS LIKELY. QPF AMOUNTS ARE NOT OVERLY IMPRESSIVE AT THIS POINT...WITH GULF MOISTURE ONLY REALLY GETTING INVOLVED IN THE MIX FOR THE LAST 6 HOURS BEFORE FROPA. THE GFS PAINTS AROUND 0.75 INCHES FOR THE CWA. GIVEN THAT THIS WON`T BE ALL RAIN...DON`T EXPECT MANY HYDRO PROBLEMS GIVEN THIS SCENARIO. ALSO...GIVEN THAT IT WON`T BE ALL SNOW EITHER /ALMOST HALF OF THIS COMES BETWEEN 00Z-06Z MONDAY AS THE GULF MOISTURE GETS INVOLVED/...IT LOOKS LIKE A POTENTIAL ADVISORY LEVEL SNOW EVENT...WITH SOME ICING BEFORE PRECIP CHANGES TO RAIN. OF COURSE...WE`RE STILL A FEW DAYS AWAY...SO STAY TUNED. POST FRONTAL WINDS WILL BE STRONG ON MONDAY WITH 50KTS UP AT 850MB AND GOOD COLD ADVECTION KEEPING US WELL MIXED BELOW. COULD SEE SOME 30-35KT GUSTS WITH PLENTY OF SHSN OFF THE LAKES MAKING IT A PRETTY WINTERY DAY. FOR TUESDAY AND WEDNESDAY...EASTERN US VORTEX IS PRETTY QUICK TO PULL OUT GIVEN LACK OF DOWNSTREAM BLOCKING. HOWEVER...THE PNA WILL CONTINUE TO BE POSITIVE...WHICH WILL KEEP THE SUPPLY OF COOL NORTHWEST FLOW GOING INTO MID WEEK. THIS WILL SPELL MCLOUDY SKIES AND NUMEROUS SNOW SHOWERS OFF THE LAKES...WITH TEMPS 7-10F COLDER THEN WHERE THEY SHOULD BE FOR THIS TIME OF YEAR. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... SURFACE FRONT MOVING THROUGH FA ATTM WITH UNRESTRICTED SHOWERS OVER NRN CWA. LATE THIS AFTERNOON THROUGH MUCH OF THE OVERNIGHT PERIOD MVFR CIGS ARE EXPECTED AT ITH/BGM WITH VFR CONTINUING AT KELM/KAVP. FURTHER NORTH, A LAKE EFFECT SNOW BAND WILL DEVELOP LATER THIS EVENING OVER NRN ONEIDA COUNTY AND CONTINUE UNTIL DAYBREAK. AT KRME, IFR CONDITIONS ARE EXPECTED AFTER 04Z DUE TO BOTH VSBY RESTRICTIONS IN SNOW AND CIGS. AFTER 14Z, THE BAND WILL MOVE NORTH OF TERMINAL WITH VFR CONDITIONS. AT KSYR, FLURRIES AND MVFR CIGS ARE EXPECTED BTW 06Z-12Z. AFTER 14Z, VFR CONDITIONS EXPECTD EVERYWHERE WITH JUST SCATTERED CU. W/SW WINDS AT 10 TO 15 KNOTS WITH GUST TO 25 KNOTS THROUGH LATE EVENING THEN WESTERLY AROUND 10 KNOTS WITH GUSTS TO 15 KNOTS. ON FRIDAY, SOUTHWEST WINDS AROUND 10 KNOTS. FOR THE 18Z FRIDAY THROUGH TUESDAY TIMEFRAME... FRIDAY NIGHT...ANOTHER ROUND OF SHSN COULD BRING SOME MVFR RESTRICTIONS...WITH RESTRICTIONS POSSIBLE INTO SATURDAY AT ALL SITES EXCEPT KAVP IN LAKE EFFECT SHSN. SATURDAY NIGHT SHOULD FEATURE IMPROVEMENT BACK TO VFR AS THE LAKE EFFECT SHSN DIMINISH. THE NEXT WEATHER SYSTEM WILL SPREAD SN INTO THE AREA DURING SUNDAY MORNING WITH IFR CONDITIONS LIKELY AT ALL TERMINALS IN SN DURING THE DAY SUNDAY. BY SUNDAY NIGHT...IFR SHOULD CONTINUE WITH A MIX WITH SN/IP POSSIBLY CHANGEOVER TO RAIN. FRONT PASSES MONDAY MORNING WITH MVFR/IFR RESTRICTIONS IN LAKE EFFECT SHSN CONTINUING THROUGH TUESDAY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 11 AM EST FRIDAY FOR NYZ009. && $$ SYNOPSIS...DJP NEAR TERM...JAB SHORT TERM...DJP LONG TERM...JMA AVIATION...RRM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1119 AM EST FRI NOV 30 2007 .SYNOPSIS... SURFACE HIGH PRESSURE WEAKEN OVER THE REGION THIS AFTERNOON. A STRONGER HIGH PRESSURE OVER THE UPPER MIDWEST TODAY... WILL BUILD SOUTHEAST INTO NORTH CAROLINA TONIGHT AND SATURDAY. THIS WILL RESULT IN A CONTINUATION OF THE SEASONABLY COOL AND DRY WEATHER INTO THE WEEKEND. A COLD FRONT WILL MOVE ACROSS THE STATE SUNDAY NIGHT. THIS WILL BRING A CHANCE OF LIGHT RAIN SUNDAY NIGHT... FOLLOWED BY COLDER AND DRY WEATHER NEXT WEEK. && .NEAR TERM /UNTIL 4 PM THIS AFTERNOON/... A 1030 MB SURFACE HIGH PRESSURE EXTENDED FROM TN ACROSS WESTERN VA AND NC LATE FRIDAY MORNING. THIS HIGH IS EXPECTED TO WEAKEN AND MOVE EAST THROUGH THE DAY ALLOWING SURFACE WINDS WILL BE LIGHT AND VARIABLE THIS AFTERNOON. THE VISIBLE SATELLITE AND UPPER AIR DATA THIS MORNING INDICTED A FEW PATCHES OF HIGH BASED STRATOCUMULUS AT 5-6KT FEET EXTENDING FROM WINSTON-SALEM AND GREENSBORO EAST TO RDU AND LOUISBURG... MOVING EASTWARD AT 20-25KT. THE LATEST RUC/GFS/NAM ALL SUGGEST THAT THESE PATCHES OF CLOUDS WILL GRADUALLY DECREASE THROUGH THE AFTERNOON AS THEY MOVE EASTWARD AND SHOULD HAVE LITTLE AFFECT ON THE MAXIMUM TEMPERATURES. LOW LEVEL THICKNESSES SUPPORT THE CURRENT FORECAST OF 55-60 N TO S. && .SHORT TERM /4 PM THIS AFTERNOON THROUGH MONDAY NIGHT/... THROUGH SUNDAY...S/W OVER THE EASTERN U.S.MOVES QUICKLY EAST. THIS FEATURE INDUCES A S/W RIDGE OVER THE DEEP SOUTH SATURDAY WHICH MIGRATES EAST SATURDAY NIGHT AND SUNDAY. SURFACE RIDGE OVERHEAD SATURDAY AND BUILDING HEIGHTS ALOFT SUPPORT ANOTHER DRY DAY WITH MAX TEMPS COMPARABLE TO HIGHS EXPECTED TODAY. FOR SATURDAY NIGHT THROUGH MONDAY...MODELS HAVE SPED UP ARRIVAL/DEPARTURE OF SURFACE FRONT AND ATTENDANT MOISTURE/LIFT COMPARED TO PREVIOUS RUNS. SURFACE RIDGE AXIS SCOOTS EWD SATURDAY NIGHT RESULTING IN A LOW LEVEL WAA PATTERN. 925-850MB FLOW BECOMES FAIRLY STOUT WITH 850MB WINDS INCREASING FROM 10 KTS TO 25-30KTS OVERNIGHT. STRENGTH OF ISENTROPIC LIFT IN THE 285-295K LAYER SUGGEST THAT POTENTIAL FOR PATCHY LIGHT RAIN EVEN THOUGH MOISTURE LAYER NOT ALL THAT DEEP (~5K FT). WILL INTRODUCE A SLIGHT CHANCE POP FOR SUN MORNING IN THE SOUTHERN PIEDMONT. 850MB FLOW OFF THE GULF WILL INCREASE MOISTURE THROUGH THE COLUMN SUN. HOWEVER FLOW VEERS TO A WLY DIRECTION PRIOR TO THE ARRIVAL THE BETTER MID/UPPER LEVEL DYNAMICS SUN NIGHT. INCREASING ISENTROPIC LIFT IN THE 285-290K LAYER SUN AFTERNOON WILL SUPPORT A CHANCE TO SLIGHT CHANCE POP ACROSS THE FORECAST AREA. STILL APPEARS THAT THE BEST CHANCE FOR RAIN WILL BE SUN NIGHT WITH THE PASSAGE OF THE SURFACE FRONT. WHILE PATCHY LIGHT RAIN A GOOD BET....PRECIP AMOUNTS WILL BE LIGHT AS BEST UPPER LEVEL SUPPORT WILL REMAIN NORTH OF THE REGION. PRESENTLY...ONLY EXPECTING PRECIP AMOUNTS FROM THIS EVENT OF LESS THAN A QUARTER OF AN INCH. LATER FORECAST MAY NEED TO BOOST HIGH CHANCE POP FOR LATE SUN/SUN NIGHT INTO THE LIKELY CATEGORY. MAX TEMPS SUN TRICKY AS INCREASING CLOUD COVERAGE/POTENTIAL FOR LIGHT RAIN MAY LIMIT TEMP RISE. IF LIGHT RAIN MORE EXTENSIVE THAN CURRENT THINKING...MAX TEMPS MAY ACTUALLY BE 5 DEGREES COOLER. NOW APPEARS THAT SURFACE FRONT WILL BE EAST OF REGION PRIOR TO 12Z MONDAY WITH SKIES RAPIDLY CLEARING NW-SE MON MORNING WITH STOUT NW FLOW IN WAKE OF SYSTEM. POTENTIAL FOR VERY DRY AIR AND BREEZY CONDITIONS MON. ALSO DECENT LOW LEVEL CAA EXPECTED. WENT WITH A LESS THAN NORMAL DIURNAL TEMP RECOVERY MON. && .LONG TERM /TUESDAY THROUGH THURSDAY/... L/W TROUGH AMPLIFIES ALONG EASTERN SEABOARD TUE-WED. THIS TRANSLATES TO A COOL AND CONTINUED DRY PERIOD FOR CENTRAL NC. MAX TEMPS TUE/WED WILL STRUGGLE TO REACH 50 EACH AFTERNOON WHILE MINS IN THE 25-30 DEGREE RANGE WILL BE COMMON. A DISTURBANCE DROPPING SEWD IN TROUGH MAY AFFECT REGION TUE NIGHT/WED. WILL BEEF UP CLOUDINESS BUT NOT EXPECTING MUCH IF ANY PRECIP AT THIS TIME. THIS SYSTEM WILL NEED TO BE MONITORED HOWEVER. TROUGH BEGINS TO LIFT N-NE THU SIGNALING THE BEGINNING OF A WARMING TREND WITH TEMPS BACK TO NORMAL BY THE END OF THE WEEK. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS WILL PERSIST THROUGH SATURDAY AS ANOTHER AREA OF HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. THE 925-850 MB HIGH WILL SHIFT OFFSHORE BY SUNDAY MORNING WITH LOW LEVEL FLOW TURNING SOUTHERLY...RESULTING IN WARM AIR ADVECTION. MVFR CEILINGS WILL BE POSSIBLE SUNDAY MORNING. A STRONG COLD FRONTAL PASSAGE IS EXPECTED SUNDAY NIGHT WITH EXTENSIVE CLOUDINESS AND THE POSSIBILITY OF LIGHT SHOWERS AND MVFR CEILINGS. VFR CONDITIONS IN DRY SUBSIDENT AIR BEHIND THE FRONT MONDAY AFTERNOON INTO TUESDAY. BREEZY TO WINDY CONDITIONS ARE LIKELY TO DEVELOP BEHIND THE FRONT ON MONDAY AFTERNOON. && .FIRE WEATHER... MAX TEMPERATURES 55 TO 60 COMBINED WITH SURFACE DEW POINTS IN THE 5-10 RANGE NW... AND TEENS SE... WILL YIELD MINIMUM RELATIVE HUMIDITY VALUES BETWEEN 13-18 PERCENT NW... AND 15-20 PERCENT SE COASTAL PLAIN. THIS SHOULD NOT BE A MAJOR CONCERN GIVEN THE EXPECTED LIGHT WINDS AND RECENT LIGHT WETTING RAIN. NO STATEMENTS ANTICIPATED THIS AFTERNOON. && .CLIMATE... NOVEMBER 2007 WILL GO DOWN AS THE DRIEST ON RECORD AT THE RALEIGH-DURHAM INTERNATIONAL AIRPORT (RDU). NOVEMBER 2007 RAINFALL OBSERVED AT RDU...0.48 OF AN INCH. THE PREVIOUS TOP 5 DRIEST NOVEMBERS AT RDU (SINCE 1944) 0.50 2001 0.61 1973 0.73 1991 0.88 1960 0.95 1981 THIS WILL ALSO BE THE 4TH DRIEST NOVEMBER ON RECORD FOR THE ENTIRE RALEIGH AREA (GOING BACK TO 1887). THE DRIEST NOVEMBER ON RECORD FOR THE RALEIGH AREA OCCURRED TWICE... (1890 AND 1931)... WHEN ONLY 0.06 INCHES WAS OBSERVED. AT THE PIEDMONT TRIAD INTERNATIONAL AIRPORT (GSO)... A BIT MORE FREQUENT RAINFALL IN NOVEMBER TOTALED OUT TO 0.84 INCHES OF RAIN... PUSHING IT OUT OF THE TOP 5 DRIEST FOR GSO. RAINFALL RECORDS FOR THE YEAR MAY BE SET... YEARLY RAINFALL AT BOTH RDU AND GSO WILL LIKELY FALL IN THE TOP 5 DRIEST BY THE END OF DECEMBER. OBSERVED RAINFALL AT RDU...31.36 INCHES (8.47 INCHES BELOW NORMAL) DRIEST ON RECORD FOR THE RALEIGH AREA (SINCE 1887)... 1. 29.93 INCHES IN 1933 2. 32.09 INCHES IN 1921 3. 33.71 INCHES IN 1976 4. 33.92 INCHES IN 1930 5. 34.43 INCHES IN 1965 OBSERVED RAINFALL AT GSO...28.28 INCHES (11.61 INCHES BELOW NORMAL) DRIEST ON RECORD FOR GSO (SINCE 1928). 1. 27.74 INCHES IN 1941 2. 29.67 INCHES IN 1986 3. 29.83 INCHES IN 2001 4. 32.44 INCHES IN 1930 5. 32.86 INCHES IN 1968 IN ADDITION BOTH RDU AND GSO NEW RECORDS COULD BE SET FOR THE FEWEST NUMBER OF DAYS WITH MEASURABLE RAINFALL IN A CALENDAR YEAR. AT RDU THERE HAS BEEN ONLY 81 DAYS OF MEASURABLE RAINFALL (0.01 OR MORE) IN 2007. THIS IS 11 DAYS LESS THAN THE RECORD LOW OF 92 DAYS SET IN 1969. AT GSO... THERE HAS BEEN 76 DAYS OF MEASURABLE RAINFALL IN 2007. THIS IS 9 DAYS LESS THAN THE RECORD OF 85 DAYS SET IN 1986. THE NORMAL NUMBER OF DAYS WITH MEASURABLE RAINFALL AT BOTH GSO AND RDU IN A CALENDAR YEAR IS 113... MEANING BOTH LOCATIONS HAVE SEEN MORE THAN A MONTHS WORTH OF FEWER RAIN DAYS THAN NORMAL. THE NORMAL NUMBER OF DAYS WITH MEASURABLE RAINFALL FOR DECEMBER AT BOTH STATIONS IS 9 DAYS. GIVEN THE CURRENT DRY PATTERN AND LACK OF FREQUENT RAIN EVENTS BOTH RDU AND GSO STAND TO SET ALL TIME RECORDS FOR THE FEWEST NUMBER OF DAYS WITH OBSERVED RAIN IN A YEAR. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT SHORT TERM...WSS LONG TERM...WSS AVIATION...RLH FIRE WEATHER...BADGETT CLIMATE...JO/PWB/BSD/CBL nc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1111 AM CST THU NOV 29 2007 .DISCUSSION... TEMPS AGAIN STRUGGLING TO RECOVER TODAY...AND INCREASING HIGH CLOUD COVER AND LIGHT WINDS WITHIN SURFACE RIDGE NOT HELPING MATTERS ANY. SIMILAR TO PAST TWO DAYS...RUC SEEMS TO HAVE BEST HANDLE ON COOLER AIR SO WILL TREND IN THAT DIRECTION COOLING HIGHS FOR TODAY...ESP IN THE NORTHERN CWA. STILL LOOK ON TRACK FOR A QUICK DUSTING OF SNOW MOVING THROUGH THE AREA TONIGHT...THOUGH STILL HAVE A LOT OF DRY AIR TO OVERCOME BEFORE PRECIP WILL BEGIN REACHING THE GROUND. WILL LIKELY BE DOING SOME ADDITIONAL FINE TUNING TO PLACEMENT OF BETTER LIGHT SNOW CHANCES TONIGHT AFTER LOOKING AT MODELS MORE CLOSELY EARLY THIS AFTERNOON. UPDATED GRIDS/PFM HAVE BEEN SENT...AND WILL GET A NEW ZFP OUT SHORTLY. && .AVIATION... HIGH CLOUDS WILL SPILL IN FROM THE WEST THROUGH THE MORNING HOURS WITH STEADILY FALLING CEILINGS INTO THE AFTERNOON. VFR EXPECTED THROUGH EARLY AFTERNOON BUT BY LATE IN THE DAY...COULD SEE CIGS DROP INTO HIGH MVFR RANGE AS NEXT COLD FRONT APPROACHES. ALSO...COULD SEE SOME SCATTERED LIGHT SNOW SHOWERS OR FLURRIES THURSDAY EVENING...BUT IS NOT LIKELY TO RESTRICT VISIBILITIES. $$ .PREV DISCUSSION... CHALLENGING FCST THIS GO AROUND...WITH MODEL DISCREPANCY LARGE WHICH DOES NOT HELP MATTERS ANY. FORGOED HEADLINES FOR NOW...BUT WE THOUGHT SERIOUSLY ABOUT THEM. MORE ON THAT LATER. IN THE NEAR TERM TODAY...NARROW BAND OF LOWER CLOUDS HANGING TOUGH JUST N OF A SUBTLE WIND SHIFT LINE IN OUR NRN FA ATTM. MORE IMPORTANTLY...THICKER HIGH CLOUDS ARE MOVG RAPIDLY EWD. THESE CLOUDS WL LIKELY TEMPER HIGH TEMPERATURES ON THE COOL SIDE TODAY. BASICALLY I TOOK THE H925 TEMPS AND RAISED THEM ABOUT 4 TO 5 DEGS...AS THERE SHOULD NOT BE A LOT OF MIXING TODAY DUE TO THE LIGHT LOW LEVEL WINDS. BUT ALL IN ALL...DUE TO LIGHT WINDS...NOT A BAD DAY IN STORE WX WISE. FOR TONIGHT...SUBTLE UPPER AIR DISTURBANCE MOVES THRU THIS AREA WITH A SFC CDFNT PASSAGE. STILL A BAND OF MID LVL FRONTOGENESIS EXISTS WITH THIS DISTURBANCE...SO KEPT SOME CHCS FOR -SN GOING RIGHT THRU THE HEART OF THE FSD FA FM W TO E. DYNAMICS RAPIDLY EXITS OUR ERN FA BETWEEN 06Z TO 09Z...SO ANY PCPN SHOULD COME TO AN END BY THEN. RH TIME SECTIONS ARE SHOWING SOME RAPIDLY DEPARTING CLOUD COVER AFT 09Z...SO LOW TEMPS COULD FALL PRETTY GOOD WITH THE MODERATELY STRONG CAA. NW FLOW MIXING POTENTIAL SHOULD HELP KEEP THE LOW TEMPS FM TOTALLY PLUMMETING HOWEVER. FRIDAY WL BE A BREEZY DAY OVR MUCH OF OUR FA WITH THE W TO NW SFC FLOW LINGERING. DEPENDING ON THE DEGREE OF MIXING...IF WE MIX ABOVE H9...MY HIGH TEMPS WL BE TOO COOL. FRIDAY NIGHT...STRONG UPPER AIR DISTURBANCE BEGINS TO DIG IN THE INTERMOUNTAIN WEST TURNING THE SFC FLOW AROUND TO THE SE. MID TO HIGH CLOUDS WL BEGIN TO RAPIDLY INCREASE FM THE SW. WITH THE INCREASING SFC WINDS AND CLOUD COVER... DECIDED TO GO WELL ABOVE GUIDANCE READINGS MOST LOCATIONS. ONE WONDERS IF EVEN THESE LOW TEMP READINGS WL BE TOO COOL IN TIME. AS FAR AS PCPN...GFS IS EXTREMELY BULLISH IN BRINGING LIGHT QPF INTO MUCH OF THE FSD FA. THE NAM HAS NONE. DECIDED TO KEEP QPF IN OUR FAR SRN FA WHERE SOME SEMBLANCE OF MSTR EXISTS BLO H7. EVEN THE RH TIME SECTIONS ON THE GFS ARE FAIRLY DRY BLO ABOUT H75 BETWEEN 06Z-12Z SAT MORNING IN OUR FAR SRN FA. THEREFORE BELIEVE THAT THE GFS IS UP TO ITS TRICKS OF OVEREXPANDING QPF AND NOT ALLOWING FOR INITIAL EVAPORATION. BUT ON SATURDAY...BOTH THE NAM AND GFS SHOW A LOT OF SATURATION BEGINNING OVR THE FA BY 12Z. THE NAM KEEPS THE SFC LOW DOWN IN THE SWRN PLAINS AND WAS DISCOUNTED. THE GEM BRINGS THE SFC LOW UP TO SIOUX CITY...WHILE THE GFS IS A BIT FURTHER SOUTH. FOR SFC WINDS... DECIDED TO GO MOSTLY WITH THE GFS BUT IN REALITY...I LIKE THE ECMWF SFC PATTERN THE BEST WITH THE SFC LOW ELONGATED FM NRN KS TO W CENTRAL IA BY 00Z SUNDAY. THIS MATCHES UP WELL WITH THE VARIOUS MODELS UPPER AIR PATTERN. VERY STRONG PV IS NOTED IN THE MID LVLS WITH THIS SYSTEM LIFTING NWD IN AN W TO E BAND ACROSS THE FA...LINGERING IN OUR ERN FA SAT NIGHT. SO THE TROP FOLD WL HAVE TO BE WATCHED IN TIME FOR SFC LOW INTENSIFICATION. AT ANY RATE... BECAUSE OF THE SRN SOLN OFFERED BY THE NAM...THE NAM H85-H7 THERMAL PROFILE IS LIKELY TOO COLD. THEREFORE FOLLOWED THE ECMWF AND GFS THERMAL PROFILE ABOVE THE SFC WHICH IS MUCH WARMER. WAA AND BROAD ASCENT IS EXTREMELY STRONG ON SATURDAY...AND AM DEFINITELY WORRIED ABOUT MIXED PCPN WORKING ITS WAY INTO NW IA AND IMMDEDIATELY ADJACENT AREAS AT LEAST BY MIDDAY SATURDAY. INITIALLY...THE THERMAL PROFILES START OFF COLD AT 12Z SATURDAY. AND WITH PLENTY OF DEEP SATURATION...ICE SHOULD BE NO PROBLEM AT THE TOP OF THE CLOUD LYR EARLY SATURDAY. BUT AS THE WARMER AIR INTRUDES IN FM H85-H7 IN OUR SERN FA BY LATE MORNING SATURDAY...WX TYPE COULD GET INTERESTING. THEREFORE OPTED TO PUT IN A WINTERY MIX THROUGH OUR SE QUARTER INTO SAT EVENING. DECIDED TO FORGO HEADLINES ATTM...BECAUSE IF THE SFC LOW PLACEMENT OFF OF THE GEM HAPPENS TO PAN OUT...IT IS NOT OUT OF THE REALM OF POSSIBILITIES THAT NW IA COULD CHANGE TO PURE RAIN BY MIDDAY SATURDAY. THIS HAS HAPPENED BEFORE. EVEN THE GFS SFC LOW PLACEMENT COULD BE CLOSE TO PURE RAIN. BUT THE ECMWF SFC LOW PLACEMENT WOULD BRING IN A LOT OF LOW LEVEL COLD AIR UNDER THE WARM AIR ALOFT...AND THIS SOLN WAS BOUGHT ATTM. DECIDED TO KEEP DIURNAL TEMP SPREADS TO A MINIMUM ON SATURDAY FOR THE OBVIOUS REASONS. SYSTEM SHOULD THEN BEGIN TO PULL OUT RATHER RAPIDLY AFTER MIDNIGHT SATURDAY NIGHT. ENDED PCPN ACCORDINGLY FM W TO E ON SUNDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ JH sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 843 PM CST FRI NOV 30 2007 .DISCUSSION... LATEST MODEL RUNS INDICATE DECENT ISENTROPIC LIFTING (295 K SURFACE) ACROSS WESTERN ZONES TONIGHT. CONDENSATION PRESSURE DEFICIT OVER THOSE AREAS SHOULD BE CLOSE TO 2 MB LATER TONIGHT. 00Z 850 MB ANALYSIS DO INDICATE SATURATION JUST SW OF CWFA. EXTREME WESTERN ZONES MAY GET SOME SPRINKLES OVERNIGHT. RUC AND NAM12 DO INDICATE LOW CLOUD COVER INCREASING AND COVERING MUCH OF CWFA TOWARD MORNING. DEWPOINTS INCHING UP FASTER THAN PREVIOUSLY ANTICIPATED ESPECIALLY OVER WESTERN HALF OF REGION. WE ADJUSTED 1ST PERIOD OF ZFPHGX ACCORDINGLY. 37 && .PREV DISCUSSION... /ISSUED 325 PM CST FRI NOV 30 2007/ DISCUSSION... SKIES HAVE BECOME PARTLY SUNNY ACROSS THE REGION WITH HIGH PRESSURE RIDGING INTO EAST TEXAS. THE PRESSURE GRADIENT IS A LITTLE TIGHTER THAN LAST NIGHT AND DON`T THINK THE SFC WINDS WILL FULLY DECOUPLE. CURRENTLY EXPECTING MORE LOW CLOUDS INSTEAD OF FOG OVERNIGHT WITH MAYBE SOME SPOTTY VERY LIGHT RAIN OR DRIZZLE OVER THE EXTREME WESTERN ZONES. SFC DEW POINTS ARE HIGHER AND WITH HIGHER WIND SPEEDS AND CLOUD COVER...THINK OVERNIGHT LOWS WILL REMAIN RATHER MILD. MOISTURE AT AND TRAPPED BENEATH A BUILDING TEMP INVERSION WILL LEAD TO MOSTLY CLOUDY SKIES SAT/SUN. COULD BE A FEW SHOWERS BENEATH THE CAP SAT/SAT NITE. A COLD FRONT COUPLED WITH SLIGHTLY HIGHER PW VALUES AND A DEPARTING RRQ WILL YIELD SLIGHTLY HIGHER RAIN CHANCES SUN AFTERNOON. SOME CONCERN THAT THE STRENGTHENING CAP WILL NOT WEAKEN SUFFICIENTLY TO ALLOW SHRA/TSRA TO DEVELOP. WILL MAINTAIN LOW END CHANCE POPS. CLEARING AND COOLER ON MONDAY WITH A GRADUAL WARM UP TUE-THU. RAIN RETURNS NEXT FRIDAY WITH INCREASED MOISTURE. HIGHER MOISTURE LEVELS WILL LINGER THROUGH NEXT WEEKEND. 43/31 CLIMATE... AVERAGE TEMPS IN NOVEMBER WERE ABOUT 2 DEGREES ABOVE NORMAL AND RAINFALL VALUES (DEPENDING ON LOCATION) WERE ABOUT 1.50 TO 2.00 INCHES ABOVE NORMAL. TODAY IS ALSO THE LAST DAY OF THE OFFICIAL HURRICANE SEASON NOT THAT WEATHER NEEDS AN OFFICIAL DAY TO START OR STOP. 43 MARINE... EASTERLY FLOW BECOMING MORE SOUTHEASTERLY AND INCREASING IN MAGNITUDE AS THE NEXT TROUGH APPROACHES THE GULF. TIGHTENING EAST-WEST PRESSURE GRADIENT WILL LIKELY PROMPT AN SCEC AS SE WINDS REACH THE 15 TO 20 KNOT RANGE. FRONT TIMED TO REACH THE COAST AROUND MONDAY AT MIDNIGHT. STRONG NORTHERLY FLOW OF AROUND 20 KNOTS...GUSTS TO NEAR 30 KNOTS...BEHIND THE BOUNDARY THROUGH MONDAY AFTERNOON. 31 AVIATION... PER SATELLITE TRENDS...HIGHER CLOUD COVER WILL MAKE ITS WAY OVER THE REGION FROM THE WEST. THE BROAD BAJA COAST LOW WILL AID IN THE TRANSPORT OF HIGH-MID LEVEL CLOUD DECK THROUGH THE PERIOD. LOWER CLOUD DECK WILL FORM AS ATMOSPHERE MOISTENS BACK UP PER INCREASING GULF FLOW. AFOREMENTIONED LOW`S TREK INTO THE ROCKIES WILL ONLY INCREASE OVERNIGHT E-SE WINDS. THUS...HAVE BACKED OFF ON THE MENTION OF DENSE FOG...ONLY INTRODUCING SHORT-LIVED MVFR FOG. CONFIDENCE IS STRONGER WITH POST-06Z DEVELOPMENT OF A MVFR (TO NEAR IFR) DECK...STRONGER SOUTH WINDS...THAN WITH ANY SIG BR/FG FORMATION. 31 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1145 AM CST FRI NOV 30 2007 .AVIATION... /18Z UPDATE/ FLYING CONDITIONS WILL DETERIORATE THROUGH THE DAY TODAY AS MOISTURE CONTINUES TO INCREASE AHEAD OF DEVELOPING SYSTEM IN THE PLAINS. CURRENTLY BKN/OVC035 CONDS PREVAIL THROUGHOUT MUCH OF NORTH TEXAS BUT MVFR CIGS ARE WIDESPREAD THROUGHOUT THE HILL COUNTRY AND WILL SPREAD NORTH LATER TODAY. EXPECT MVFR CIGS FOR BKN/OVC025 LATER THIS AFTERNOON...TO GRADUALLY LOWER THIS EVENING TO AROUND 1000FT. SOUTHEAST FLOW WILL CONTINUE AND WILL INCREASE OVERNIGHT AS SFC LOW RAPIDLY DEEPENS IN THE LEE OF THE ROCKIES. IFR CONDS FOR OVC008 CIGS AND DRIZZLE/LIGHT SHOWERS SHOULD PREVAIL ACROSS THE REGION DURING THE OVERNIGHT HOURS. LITTLE IMPROVEMENT IS EXPECTED THROUGH SATURDAY MORNING. WINDS WILL BECOME GUSTY BY MID AFTERNOON AT 16020G30KT WITH LOW LEVEL WINDS INCREASING TO 55KTS AT 3KFT BY MID AFTN. 91/DUNN && .PREV DISCUSSION... /ISSUED 1003 AM CST FRI NOV 30 2007/ UPDATE...CURRENT FORECAST IS IN GOOD SHAPE AND WILL ONLY MAKE SOME MINOR ADJUSTMENTS TO HOURLY GRIDS. WILL ALSO MENTION ISOLATED SPRINKLES ALL AREAS THROUGH THE DAY BASED ON WEAK RADAR RETURNS. LOW LEVEL WARM ADVECTION TO CONTINUE INCREASING THROUGH THE DAY WITH MORNING PWS ALREADY IN EXCESS OF 1 INCH...WOULD EXPECT AREAS OF DRIZZLE/LIGHT SHOWERS TO BE ONGOING BY THIS EVENING... ESPECIALLY OUT WEST. TEMPS WILL WARM INTO THE MID 60S BY AFTN... WITH A MUCH WARMER NIGHT EXPECTED. 91/DUNN && .PREV DISCUSSION... /ISSUED 329 AM CST FRI NOV 30 2007/ SIGNS OF CHANGING WEATHER CONDITIONS ARE ALREADY EVIDENT THIS MORNING VIA SURFACE/UPPER LEVEL ANALYSES AND THE REGIONAL RADAR MOSAIC. SURFACE AND LOW LEVEL WINDS HAVE SHIFTED TO THE SOUTH...AND SFC DEWPOINTS IN THE MID TO UPPER 50S ARE PRESENT ACROSS SOUTHEAST AND DEEP SOUTH TEXAS. ISENTROPIC LIFT IN THE MID LEVELS /PER 00 HR RUC ANALYSIS/ ASSOCIATED WITH LOW CONDENSATION PRESSURE DEFICITS IN THE 675-625MB LAYER ARE LIKELY CONTRIBUTING TO THE DEVELOPMENT OF RADAR ECHOES PRESENTLY STRETCHING FROM NEAR CHILDRESS...ACROSS SOUTHERN OKLAHOMA...AND INTO WEST CENTRAL ARKANSAS. INTERMITTENT SURFACE OBSERVATIONS UNDER THE ECHOES ARE REPORTING LIGHT RAIN/DRIZZLE...BUT THE MAJORITY OF THIS ACTIVITY WILL EVAPORATE BEFORE REACHING THE GROUND...UNTIL LOWER LEVELS CAN SUFFICIENTLY SATURATE. NEVERTHELESS...ISOLATED SPRINKLES WILL BE POSSIBLE ALONG THE RED RIVER THROUGH THE LATE MORNING HOURS AND HAVE ADDED THIS TO THE GRIDS ACCORDINGLY. UPPER LEVEL LOW CONTINUES TO SPIN WEST OF BAJA...BUT THE LAST FEW IMAGES DEPICT SOME DIFFLUENCE JUST NORTH OF THE CENTER OF CIRCULATION...INDICATING THE LOW MAY BE PREPARING TO LIFT OUT. THIS IS ALSO SUPPORTED BY THE CURRENT RUC UPPER LEVEL HEIGHT ANALYSIS... WHICH INDICATES THE LOW IS BEGINNING TO TRANSITION INTO AN OPEN WAVE. NORTH TEXAS WILL EXPERIENCE AN INCREASE IN CLOUDINESS TODAY...HOWEVER SOUTHWEST LOW LEVEL WINDS WILL CONTRIBUTE TO WARM AIR ADVECTION OVER MUCH OF WEST AND CENTRAL TEXAS...USHERING H85 TEMPS BETWEEN 12 AND 14C INTO OUR WESTERN AND SOUTHWESTERN ZONES TODAY. AS A RESULT...THIS AREA WILL ALSO WITNESS THE WARMEST HIGHS TODAY /UPPER 60S TO NEAR 70/. DEEPER LOW LEVEL MOISTURE AND LOW CLOUDS WILL BE MOVING FROM SOUTH TO NORTH LATE THIS AFTERNOON ACROSS CENTRAL TEXAS...AND OVERSPREAD PORTIONS OF NORTH TEXAS TONIGHT. LOW LEVEL ISENTROPIC LIFT /295K AND 300K SURFACES/ REALLY KICKS INTO GEAR ALONG AND WEST OF THE INTERSTATE 35 CORRIDOR BETWEEN 18Z AND 00Z TODAY...ALONG WITH A SURGING 1000-850MB THETA-E RIDGE. SPRINKLES/SHOWERS WILL LIKELY MOVE NORTHWARD OUT OF THE HILL COUNTRY LATE THIS AFTERNOON /21-00Z/ AND MAY AFFECT SOUTHWEST PORTIONS OF THE CWA AND HAVE ADDED THIS MENTION TO THE GRIDS. LITTLE CHANGE FROM THE LAST COUPLE OF FORECAST CYCLES IN REGARDS TO POSITION OF STRONGEST LOW LEVEL MOIST TRAJECTORIES LATE TONIGHT AND INTO TOMORROW...WHICH WILL GENERALLY BE ALONG AND WEST I-35. WILL CONTINUE TO MAINTAIN THE HIGHEST POPS IN OUR WEST. AREAL COVERAGE IS QUESTIONABLE THROUGH MIDDAY TOMORROW ACROSS OUR FAR EASTERN ZONES...AND WILL ONLY CARRY ISOLATED SHOWERS ALONG AND EAST OF A PARIS TO CAMERON LINE THRU 18Z SATURDAY. SATURDAY WILL BE WINDY ACROSS NORTH TEXAS AS A SFC LOW DEEPENS OVER EASTERN COLORADO. EXPECT WINDS SUSTAINED NEAR 20 MPH WITH GUSTS UP TO 30 MPH POSSIBLE AREA WIDE. WITH STRONG SOUTHERLY LOW LEVEL FLOW /LLJ 40-50KTS/...HIGHS WILL BE QUITE A BIT ABOVE NORMAL. AM RELUCTANT TO GO AS HIGH AS MAV ON SAT AS CLOUD COVER AND SHOWERS WILL PREVENT MAXIMUM INSOLATION. COOL FRONT WILL PUSH THROUGH NORTH TEXAS ON SUNDAY...BUT WITH PACIFIC ORIGINS...DO NOT EXPECT A MAJOR COOL DOWN OR SIGNIFICANTLY DRIER DEWPOINTS. BREEZY DOWNSLOPE WINDS ON SUNDAY WILL ALLOW THE AREA TO REALLY WARM UP...PARTICULARLY OVER CENTRAL TEXAS /WHERE HIGHS MAY CLIMB INTO THE UPPER 70S TO NEAR 80 DEGREES/. COOLER AIR WILL WORK INTO NORTH TEXAS BY MONDAY...KNOCKING HIGHS BACK TO MORE SEASONABLE READINGS FOR EARLY DECEMBER /LOWER 60S/. ALTHOUGH SOME ISENTROPIC LIFT WILL BE PRESENT OVER THE CWA LATE SAT NIGHT AND INTO SUN MORNING...MODELS SUGGEST THE GREATEST SATURATION WILL PUSH OFF TO OUR EAST AND NORTHEAST /AS INDICATED BY CONDENSATION PRESSURE DEFICITS/. THEREFORE...THIS EVENT MAY BE WRAPPING UP AFTER MIDNIGHT SUN MORNING FOR MUCH OF NORTH TEXAS...BUT A FEW LINGERING SHOWERS/DRIZZLE MAY BE POSSIBLE. BELIEVE THAT SLIGHT CHANCE POPS TAPERING FROM WEST TO EAST WILL ADDRESS THE UNCERTAINTY FOR NOW. SURFACE HIGH PRESSURE WILL BUILD ACROSS NORTH TEXAS ON TUESDAY...WHILE RISING MID LEVEL HEIGHTS COMMENCE /DUE TO RIDGING ACROSS THE SOUTHWESTERN CONUS/. HIGH TEMPS WILL HOVER IN THE UPPER 60S AND LOWER 70S ON TUES AND WED. MEDIUM RANGE GUIDANCE SUGGESTS THE MID/UPPER LEVEL RIDGE WILL BREAK DOWN MID WEEK...ALLOWING FOR A SHORTWAVE TROF TO DROP INTO THE REGION LATE IN THE WEEK...AND BRING A CHANCE FOR SHOWERS BY NEXT FRIDAY. AT THIS TIME...NO FREEZES ARE EXPECTED FOR NORTH TEXAS OVER THE NEXT SEVERAL DAYS...AS LOW TEMPERATURES WILL GENERALLY STAY IN THE UPPER 30S OR HIGHER THROUGH THE UPCOMING WEEK. HOWEVER...NORTHWEST PORTIONS OF THE CWA MAY HAVE A SHOT AT FROST MONDAY MORNING...AS TEMPERATURES AND DEWPOINTS DROP INTO THE LOWER 30S. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 58 71 64 75 / 10 20 30 20 10 WACO, TX 69 61 72 66 78 / 10 30 30 20 10 PARIS, TX 58 50 69 62 74 / 10 10 30 20 20 DENTON, TX 63 58 71 61 74 / 10 30 30 20 10 MCKINNEY, TX 61 56 69 62 75 / 10 20 30 20 10 DALLAS, TX 65 59 71 64 75 / 10 20 30 20 10 TERRELL, TX 64 57 71 65 76 / 10 10 30 20 20 CORSICANA, TX 67 58 72 65 79 / 10 10 20 20 20 TEMPLE, TX 69 62 72 64 80 / 10 30 30 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1003 AM CST FRI NOV 30 2007 .UPDATE...CURRENT FORECAST IS IN GOOD SHAPE AND WILL ONLY MAKE SOME MINOR ADJUSTMENTS TO HOURLY GRIDS. WILL ALSO MENTION ISOLATED SPRINKLES ALL AREAS THROUGH THE DAY BASED ON WEAK RADAR RETURNS. LOW LEVEL WARM ADVECTION TO CONTINUE INCREASING THROUGH THE DAY WITH MORNING PWS ALREADY IN EXCESS OF 1 INCH...WOULD EXPECT AREAS OF DRIZZLE/LIGHT SHOWERS TO BE ONGOING BY THIS EVENING... ESPECIALLY OUT WEST. TEMPS WILL WARM INTO THE MID 60S BY AFTN... WITH A MUCH WARMER NIGHT EXPECTED. 91/DUNN && .PREV DISCUSSION... /ISSUED 525 AM CST FRI NOV 30 2007/ VFR CIGS FOR THE TIME BEING AT ALL TAF SITES. HOWEVER...MVFR CEILINGS...CURRENTLY OVER THE BIG COUNTRY AND HILL COUNTRY WILL CONTINUE TO WORK NORTHWARD AND SHOULD REACH WACO AROUND 15Z AND THE METROPLEX TAF SITES AROUND 17Z. EXPECT MVFR CEILINGS TO PREVAIL THROUGH THE AFTERNOON AND OVERNIGHT WITH STRONG LOW LEVEL WARM AIR ADVECTION PATTERN IN PLACE. VISIBILITIES WILL ALSO OCCASIONALLY FALL TO MVFR THIS MORNING...ESPECIALLY IN WACO. DO NOT EXPECT IFR VISIBILITIES...CURRENTLY OVER THE HILL COUNTRY...TO AFFECT ANY OF THE TAF SITES THIS MORNING. PATCHY FOG SHOULD FORM AGAIN OVERNIGHT. HOWEVER...VISIBILITIES SHOULD REMAIN AT 3 MILES OR BETTER DUE TO A STRONGER SURFACE WIND. THERE MAY BE A FEW SHOWERS THIS EVENING AND OVERNIGHT...BUT BEST COVERAGE OF SHOWERS WILL BE WEST OF THE INTERSTATE 35 CORRIDOR. 79... && .PREV DISCUSSION... /ISSUED 329 AM CST FRI NOV 30 2007/ SIGNS OF CHANGING WEATHER CONDITIONS ARE ALREADY EVIDENT THIS MORNING VIA SURFACE/UPPER LEVEL ANALYSES AND THE REGIONAL RADAR MOSAIC. SURFACE AND LOW LEVEL WINDS HAVE SHIFTED TO THE SOUTH...AND SFC DEWPOINTS IN THE MID TO UPPER 50S ARE PRESENT ACROSS SOUTHEAST AND DEEP SOUTH TEXAS. ISENTROPIC LIFT IN THE MID LEVELS /PER 00 HR RUC ANALYSIS/ ASSOCIATED WITH LOW CONDENSATION PRESSURE DEFICITS IN THE 675-625MB LAYER ARE LIKELY CONTRIBUTING TO THE DEVELOPMENT OF RADAR ECHOES PRESENTLY STRETCHING FROM NEAR CHILDRESS...ACROSS SOUTHERN OKLAHOMA...AND INTO WEST CENTRAL ARKANSAS. INTERMITTENT SURFACE OBSERVATIONS UNDER THE ECHOES ARE REPORTING LIGHT RAIN/DRIZZLE...BUT THE MAJORITY OF THIS ACTIVITY WILL EVAPORATE BEFORE REACHING THE GROUND...UNTIL LOWER LEVELS CAN SUFFICIENTLY SATURATE. NEVERTHELESS...ISOLATED SPRINKLES WILL BE POSSIBLE ALONG THE RED RIVER THROUGH THE LATE MORNING HOURS AND HAVE ADDED THIS TO THE GRIDS ACCORDINGLY. UPPER LEVEL LOW CONTINUES TO SPIN WEST OF BAJA...BUT THE LAST FEW IMAGES DEPICT SOME DIFFLUENCE JUST NORTH OF THE CENTER OF CIRCULATION...INDICATING THE LOW MAY BE PREPARING TO LIFT OUT. THIS IS ALSO SUPPORTED BY THE CURRENT RUC UPPER LEVEL HEIGHT ANALYSIS... WHICH INDICATES THE LOW IS BEGINNING TO TRANSITION INTO AN OPEN WAVE. NORTH TEXAS WILL EXPERIENCE AN INCREASE IN CLOUDINESS TODAY...HOWEVER SOUTHWEST LOW LEVEL WINDS WILL CONTRIBUTE TO WARM AIR ADVECTION OVER MUCH OF WEST AND CENTRAL TEXAS...USHERING H85 TEMPS BETWEEN 12 AND 14C INTO OUR WESTERN AND SOUTHWESTERN ZONES TODAY. AS A RESULT...THIS AREA WILL ALSO WITNESS THE WARMEST HIGHS TODAY /UPPER 60S TO NEAR 70/. DEEPER LOW LEVEL MOISTURE AND LOW CLOUDS WILL BE MOVING FROM SOUTH TO NORTH LATE THIS AFTERNOON ACROSS CENTRAL TEXAS...AND OVERSPREAD PORTIONS OF NORTH TEXAS TONIGHT. LOW LEVEL ISENTROPIC LIFT /295K AND 300K SURFACES/ REALLY KICKS INTO GEAR ALONG AND WEST OF THE INTERSTATE 35 CORRIDOR BETWEEN 18Z AND 00Z TODAY...ALONG WITH A SURGING 1000-850MB THETA-E RIDGE. SPRINKLES/SHOWERS WILL LIKELY MOVE NORTHWARD OUT OF THE HILL COUNTRY LATE THIS AFTERNOON /21-00Z/ AND MAY AFFECT SOUTHWEST PORTIONS OF THE CWA AND HAVE ADDED THIS MENTION TO THE GRIDS. LITTLE CHANGE FROM THE LAST COUPLE OF FORECAST CYCLES IN REGARDS TO POSITION OF STRONGEST LOW LEVEL MOIST TRAJECTORIES LATE TONIGHT AND INTO TOMORROW...WHICH WILL GENERALLY BE ALONG AND WEST I-35. WILL CONTINUE TO MAINTAIN THE HIGHEST POPS IN OUR WEST. AREAL COVERAGE IS QUESTIONABLE THROUGH MIDDAY TOMORROW ACROSS OUR FAR EASTERN ZONES...AND WILL ONLY CARRY ISOLATED SHOWERS ALONG AND EAST OF A PARIS TO CAMERON LINE THRU 18Z SATURDAY. SATURDAY WILL BE WINDY ACROSS NORTH TEXAS AS A SFC LOW DEEPENS OVER EASTERN COLORADO. EXPECT WINDS SUSTAINED NEAR 20 MPH WITH GUSTS UP TO 30 MPH POSSIBLE AREA WIDE. WITH STRONG SOUTHERLY LOW LEVEL FLOW /LLJ 40-50KTS/...HIGHS WILL BE QUITE A BIT ABOVE NORMAL. AM RELUCTANT TO GO AS HIGH AS MAV ON SAT AS CLOUD COVER AND SHOWERS WILL PREVENT MAXIMUM INSOLATION. COOL FRONT WILL PUSH THROUGH NORTH TEXAS ON SUNDAY...BUT WITH PACIFIC ORIGINS...DO NOT EXPECT A MAJOR COOL DOWN OR SIGNIFICANTLY DRIER DEWPOINTS. BREEZY DOWNSLOPE WINDS ON SUNDAY WILL ALLOW THE AREA TO REALLY WARM UP...PARTICULARLY OVER CENTRAL TEXAS /WHERE HIGHS MAY CLIMB INTO THE UPPER 70S TO NEAR 80 DEGREES/. COOLER AIR WILL WORK INTO NORTH TEXAS BY MONDAY...KNOCKING HIGHS BACK TO MORE SEASONABLE READINGS FOR EARLY DECEMBER /LOWER 60S/. ALTHOUGH SOME ISENTROPIC LIFT WILL BE PRESENT OVER THE CWA LATE SAT NIGHT AND INTO SUN MORNING...MODELS SUGGEST THE GREATEST SATURATION WILL PUSH OFF TO OUR EAST AND NORTHEAST /AS INDICATED BY CONDENSATION PRESSURE DEFICITS/. THEREFORE...THIS EVENT MAY BE WRAPPING UP AFTER MIDNIGHT SUN MORNING FOR MUCH OF NORTH TEXAS...BUT A FEW LINGERING SHOWERS/DRIZZLE MAY BE POSSIBLE. BELIEVE THAT SLIGHT CHANCE POPS TAPERING FROM WEST TO EAST WILL ADDRESS THE UNCERTAINTY FOR NOW. SURFACE HIGH PRESSURE WILL BUILD ACROSS NORTH TEXAS ON TUESDAY...WHILE RISING MID LEVEL HEIGHTS COMMENCE /DUE TO RIDGING ACROSS THE SOUTHWESTERN CONUS/. HIGH TEMPS WILL HOVER IN THE UPPER 60S AND LOWER 70S ON TUES AND WED. MEDIUM RANGE GUIDANCE SUGGESTS THE MID/UPPER LEVEL RIDGE WILL BREAK DOWN MID WEEK...ALLOWING FOR A SHORTWAVE TROF TO DROP INTO THE REGION LATE IN THE WEEK...AND BRING A CHANCE FOR SHOWERS BY NEXT FRIDAY. AT THIS TIME...NO FREEZES ARE EXPECTED FOR NORTH TEXAS OVER THE NEXT SEVERAL DAYS...AS LOW TEMPERATURES WILL GENERALLY STAY IN THE UPPER 30S OR HIGHER THROUGH THE UPCOMING WEEK. HOWEVER...NORTHWEST PORTIONS OF THE CWA MAY HAVE A SHOT AT FROST MONDAY MORNING...AS TEMPERATURES AND DEWPOINTS DROP INTO THE LOWER 30S. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 58 71 64 75 / 10 20 30 20 10 WACO, TX 69 61 72 66 78 / 10 30 30 20 10 PARIS, TX 58 50 69 62 74 / 10 10 30 20 20 DENTON, TX 63 58 71 61 74 / 10 30 30 20 10 MCKINNEY, TX 61 56 69 62 75 / 10 20 30 20 10 DALLAS, TX 65 59 71 64 75 / 10 20 30 20 10 TERRELL, TX 64 57 71 65 76 / 10 10 30 20 20 CORSICANA, TX 67 58 72 65 79 / 10 10 20 20 20 TEMPLE, TX 69 62 72 64 80 / 10 30 30 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 525 AM CST FRI NOV 30 2007 .AVIATION... VFR CIGS FOR THE TIME BEING AT ALL TAF SITES. HOWEVER...MVFR CEILINGS...CURRENTLY OVER THE BIG COUNTRY AND HILL COUNTRY WILL CONTINUE TO WORK NORTHWARD AND SHOULD REACH WACO AROUND 15Z AND THE METROPLEX TAF SITES AROUND 17Z. EXPECT MVFR CEILINGS TO PREVAIL THROUGH THE AFTERNOON AND OVERNIGHT WITH STRONG LOW LEVEL WARM AIR ADVECTION PATTERN IN PLACE. VISIBILITIES WILL ALSO OCCASIONALLY FALL TO MVFR THIS MORNING...ESPECIALLY IN WACO. DO NOT EXPECT IFR VISIBILITIES...CURRENTLY OVER THE HILL COUNTRY...TO AFFECT ANY OF THE TAF SITES THIS MORNING. PATCHY FOG SHOULD FORM AGAIN OVERNIGHT. HOWEVER...VISIBILITIES SHOULD REMAIN AT 3 MILES OR BETTER DUE TO A STRONGER SURFACE WIND. THERE MAY BE A FEW SHOWERS THIS EVENING AND OVERNIGHT...BUT BEST COVERAGE OF SHOWERS WILL BE WEST OF THE INTERSTATE 35 CORRIDOR. .79... && .DISCUSSION... 329 AM CST SIGNS OF CHANGING WEATHER CONDITIONS ARE ALREADY EVIDENT THIS MORNING VIA SURFACE/UPPER LEVEL ANALYSES AND THE REGIONAL RADAR MOSAIC. SURFACE AND LOW LEVEL WINDS HAVE SHIFTED TO THE SOUTH...AND SFC DEWPOINTS IN THE MID TO UPPER 50S ARE PRESENT ACROSS SOUTHEAST AND DEEP SOUTH TEXAS. ISENTROPIC LIFT IN THE MID LEVELS /PER 00 HR RUC ANALYSIS/ ASSOCIATED WITH LOW CONDENSATION PRESSURE DEFICITS IN THE 675-625MB LAYER ARE LIKELY CONTRIBUTING TO THE DEVELOPMENT OF RADAR ECHOES PRESENTLY STRETCHING FROM NEAR CHILDRESS...ACROSS SOUTHERN OKLAHOMA...AND INTO WEST CENTRAL ARKANSAS. INTERMITTENT SURFACE OBSERVATIONS UNDER THE ECHOES ARE REPORTING LIGHT RAIN/DRIZZLE...BUT THE MAJORITY OF THIS ACTIVITY WILL EVAPORATE BEFORE REACHING THE GROUND...UNTIL LOWER LEVELS CAN SUFFICIENTLY SATURATE. NEVERTHELESS...ISOLATED SPRINKLES WILL BE POSSIBLE ALONG THE RED RIVER THROUGH THE LATE MORNING HOURS AND HAVE ADDED THIS TO THE GRIDS ACCORDINGLY. UPPER LEVEL LOW CONTINUES TO SPIN WEST OF BAJA...BUT THE LAST FEW IMAGES DEPICT SOME DIFFLUENCE JUST NORTH OF THE CENTER OF CIRCULATION...INDICATING THE LOW MAY BE PREPARING TO LIFT OUT. THIS IS ALSO SUPPORTED BY THE CURRENT RUC UPPER LEVEL HEIGHT ANALYSIS... WHICH INDICATES THE LOW IS BEGINNING TO TRANSITION INTO AN OPEN WAVE. NORTH TEXAS WILL EXPERIENCE AN INCREASE IN CLOUDINESS TODAY...HOWEVER SOUTHWEST LOW LEVEL WINDS WILL CONTRIBUTE TO WARM AIR ADVECTION OVER MUCH OF WEST AND CENTRAL TEXAS...USHERING H85 TEMPS BETWEEN 12 AND 14C INTO OUR WESTERN AND SOUTHWESTERN ZONES TODAY. AS A RESULT...THIS AREA WILL ALSO WITNESS THE WARMEST HIGHS TODAY /UPPER 60S TO NEAR 70/. DEEPER LOW LEVEL MOISTURE AND LOW CLOUDS WILL BE MOVING FROM SOUTH TO NORTH LATE THIS AFTERNOON ACROSS CENTRAL TEXAS...AND OVERSPREAD PORTIONS OF NORTH TEXAS TONIGHT. LOW LEVEL ISENTROPIC LIFT /295K AND 300K SURFACES/ REALLY KICKS INTO GEAR ALONG AND WEST OF THE INTERSTATE 35 CORRIDOR BETWEEN 18Z AND 00Z TODAY...ALONG WITH A SURGING 1000-850MB THETA-E RIDGE. SPRINKLES/SHOWERS WILL LIKELY MOVE NORTHWARD OUT OF THE HILL COUNTRY LATE THIS AFTERNOON /21-00Z/ AND MAY AFFECT SOUTHWEST PORTIONS OF THE CWA AND HAVE ADDED THIS MENTION TO THE GRIDS. LITTLE CHANGE FROM THE LAST COUPLE OF FORECAST CYCLES IN REGARDS TO POSITION OF STRONGEST LOW LEVEL MOIST TRAJECTORIES LATE TONIGHT AND INTO TOMORROW...WHICH WILL GENERALLY BE ALONG AND WEST I-35. WILL CONTINUE TO MAINTAIN THE HIGHEST POPS IN OUR WEST. AREAL COVERAGE IS QUESTIONABLE THROUGH MIDDAY TOMORROW ACROSS OUR FAR EASTERN ZONES...AND WILL ONLY CARRY ISOLATED SHOWERS ALONG AND EAST OF A PARIS TO CAMERON LINE THRU 18Z SATURDAY. SATURDAY WILL BE WINDY ACROSS NORTH TEXAS AS A SFC LOW DEEPENS OVER EASTERN COLORADO. EXPECT WINDS SUSTAINED NEAR 20 MPH WITH GUSTS UP TO 30 MPH POSSIBLE AREA WIDE. WITH STRONG SOUTHERLY LOW LEVEL FLOW /LLJ 40-50KTS/...HIGHS WILL BE QUITE A BIT ABOVE NORMAL. AM RELUCTANT TO GO AS HIGH AS MAV ON SAT AS CLOUD COVER AND SHOWERS WILL PREVENT MAXIMUM INSOLATION. COOL FRONT WILL PUSH THROUGH NORTH TEXAS ON SUNDAY...BUT WITH PACIFIC ORIGINS...DO NOT EXPECT A MAJOR COOL DOWN OR SIGNIFICANTLY DRIER DEWPOINTS. BREEZY DOWNSLOPE WINDS ON SUNDAY WILL ALLOW THE AREA TO REALLY WARM UP...PARTICULARLY OVER CENTRAL TEXAS /WHERE HIGHS MAY CLIMB INTO THE UPPER 70S TO NEAR 80 DEGREES/. COOLER AIR WILL WORK INTO NORTH TEXAS BY MONDAY...KNOCKING HIGHS BACK TO MORE SEASONABLE READINGS FOR EARLY DECEMBER /LOWER 60S/. ALTHOUGH SOME ISENTROPIC LIFT WILL BE PRESENT OVER THE CWA LATE SAT NIGHT AND INTO SUN MORNING...MODELS SUGGEST THE GREATEST SATURATION WILL PUSH OFF TO OUR EAST AND NORTHEAST /AS INDICATED BY CONDENSATION PRESSURE DEFICITS/. THEREFORE...THIS EVENT MAY BE WRAPPING UP AFTER MIDNIGHT SUN MORNING FOR MUCH OF NORTH TEXAS...BUT A FEW LINGERING SHOWERS/DRIZZLE MAY BE POSSIBLE. BELIEVE THAT SLIGHT CHANCE POPS TAPERING FROM WEST TO EAST WILL ADDRESS THE UNCERTAINTY FOR NOW. SURFACE HIGH PRESSURE WILL BUILD ACROSS NORTH TEXAS ON TUESDAY...WHILE RISING MID LEVEL HEIGHTS COMMENCE /DUE TO RIDGING ACROSS THE SOUTHWESTERN CONUS/. HIGH TEMPS WILL HOVER IN THE UPPER 60S AND LOWER 70S ON TUES AND WED. MEDIUM RANGE GUIDANCE SUGGESTS THE MID/UPPER LEVEL RIDGE WILL BREAK DOWN MID WEEK...ALLOWING FOR A SHORTWAVE TROF TO DROP INTO THE REGION LATE IN THE WEEK...AND BRING A CHANCE FOR SHOWERS BY NEXT FRIDAY. AT THIS TIME...NO FREEZES ARE EXPECTED FOR NORTH TEXAS OVER THE NEXT SEVERAL DAYS...AS LOW TEMPERATURES WILL GENERALLY STAY IN THE UPPER 30S OR HIGHER THROUGH THE UPCOMING WEEK. HOWEVER...NORTHWEST PORTIONS OF THE CWA MAY HAVE A SHOT AT FROST MONDAY MORNING...AS TEMPERATURES AND DEWPOINTS DROP INTO THE LOWER 30S. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 58 71 64 75 / 10 20 30 20 10 WACO, TX 69 61 72 66 78 / 10 30 30 20 10 PARIS, TX 58 50 69 62 74 / 10 10 30 20 20 DENTON, TX 63 58 71 61 74 / 10 30 30 20 10 MCKINNEY, TX 61 56 69 62 75 / 10 20 30 20 10 DALLAS, TX 65 59 71 64 75 / 10 20 30 20 10 TERRELL, TX 64 57 71 65 76 / 10 10 30 20 20 CORSICANA, TX 67 58 72 65 79 / 10 10 20 20 20 TEMPLE, TX 69 62 72 64 80 / 10 30 30 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 329 AM CST FRI NOV 30 2007 .DISCUSSION... SIGNS OF CHANGING WEATHER CONDITIONS ARE ALREADY EVIDENT THIS MORNING VIA SURFACE/UPPER LEVEL ANALYSES AND THE REGIONAL RADAR MOSAIC. SURFACE AND LOW LEVEL WINDS HAVE SHIFTED TO THE SOUTH...AND SFC DEWPOINTS IN THE MID TO UPPER 50S ARE PRESENT ACROSS SOUTHEAST AND DEEP SOUTH TEXAS. ISENTROPIC LIFT IN THE MID LEVELS /PER 00 HR RUC ANALYSIS/ ASSOCIATED WITH LOW CONDENSATION PRESSURE DEFICITS IN THE 675-625MB LAYER ARE LIKELY CONTRIBUTING TO THE DEVELOPMENT OF RADAR ECHOES PRESENTLY STRETCHING FROM NEAR CHILDRESS...ACROSS SOUTHERN OKLAHOMA...AND INTO WEST CENTRAL ARKANSAS. INTERMITTENT SURFACE OBSERVATIONS UNDER THE ECHOES ARE REPORTING LIGHT RAIN/DRIZZLE...BUT THE MAJORITY OF THIS ACTIVITY WILL EVAPORATE BEFORE REACHING THE GROUND...UNTIL LOWER LEVELS CAN SUFFICIENTLY SATURATE. NEVERTHELESS...ISOLATED SPRINKLES WILL BE POSSIBLE ALONG THE RED RIVER THROUGH THE LATE MORNING HOURS AND HAVE ADDED THIS TO THE GRIDS ACCORDINGLY. UPPER LEVEL LOW CONTINUES TO SPIN WEST OF BAJA...BUT THE LAST FEW IMAGES DEPICT SOME DIFFLUENCE JUST NORTH OF THE CENTER OF CIRCULATION...INDICATING THE LOW MAY BE PREPARING TO LIFT OUT. THIS IS ALSO SUPPORTED BY THE CURRENT RUC UPPER LEVEL HEIGHT ANALYSIS... WHICH INDICATES THE LOW IS BEGINNING TO TRANSITION INTO AN OPEN WAVE. NORTH TEXAS WILL EXPERIENCE AN INCREASE IN CLOUDINESS TODAY...HOWEVER SOUTHWEST LOW LEVEL WINDS WILL CONTRIBUTE TO WARM AIR ADVECTION OVER MUCH OF WEST AND CENTRAL TEXAS...USHERING H85 TEMPS BETWEEN 12 AND 14C INTO OUR WESTERN AND SOUTHWESTERN ZONES TODAY. AS A RESULT...THIS AREA WILL ALSO WITNESS THE WARMEST HIGHS TODAY /UPPER 60S TO NEAR 70/. DEEPER LOW LEVEL MOISTURE AND LOW CLOUDS WILL BE MOVING FROM SOUTH TO NORTH LATE THIS AFTERNOON ACROSS CENTRAL TEXAS...AND OVERSPREAD PORTIONS OF NORTH TEXAS TONIGHT. LOW LEVEL ISENTROPIC LIFT /295K AND 300K SURFACES/ REALLY KICKS INTO GEAR ALONG AND WEST OF THE INTERSTATE 35 CORRIDOR BETWEEN 18Z AND 00Z TODAY...ALONG WITH A SURGING 1000-850MB THETA-E RIDGE. SPRINKLES/SHOWERS WILL LIKELY MOVE NORTHWARD OUT OF THE HILL COUNTRY LATE THIS AFTERNOON /21-00Z/ AND MAY AFFECT SOUTHWEST PORTIONS OF THE CWA AND HAVE ADDED THIS MENTION TO THE GRIDS. LITTLE CHANGE FROM THE LAST COUPLE OF FORECAST CYCLES IN REGARDS TO POSITION OF STRONGEST LOW LEVEL MOIST TRAJECTORIES LATE TONIGHT AND INTO TOMORROW...WHICH WILL GENERALLY BE ALONG AND WEST I-35. WILL CONTINUE TO MAINTAIN THE HIGHEST POPS IN OUR WEST. AREAL COVERAGE IS QUESTIONABLE THROUGH MIDDAY TOMORROW ACROSS OUR FAR EASTERN ZONES...AND WILL ONLY CARRY ISOLATED SHOWERS ALONG AND EAST OF A PARIS TO CAMERON LINE THRU 18Z SATURDAY. SATURDAY WILL BE WINDY ACROSS NORTH TEXAS AS A SFC LOW DEEPENS OVER EASTERN COLORADO. EXPECT WINDS SUSTAINED NEAR 20 MPH WITH GUSTS UP TO 30 MPH POSSIBLE AREA WIDE. WITH STRONG SOUTHERLY LOW LEVEL FLOW /LLJ 40-50KTS/...HIGHS WILL BE QUITE A BIT ABOVE NORMAL. AM RELUCTANT TO GO AS HIGH AS MAV ON SAT AS CLOUD COVER AND SHOWERS WILL PREVENT MAXIMUM INSOLATION. COOL FRONT WILL PUSH THROUGH NORTH TEXAS ON SUNDAY...BUT WITH PACIFIC ORIGINS...DO NOT EXPECT A MAJOR COOL DOWN OR SIGNIFICANTLY DRIER DEWPOINTS. BREEZY DOWNSLOPE WINDS ON SUNDAY WILL ALLOW THE AREA TO REALLY WARM UP...PARTICULARLY OVER CENTRAL TEXAS /WHERE HIGHS MAY CLIMB INTO THE UPPER 70S TO NEAR 80 DEGREES/. COOLER AIR WILL WORK INTO NORTH TEXAS BY MONDAY...KNOCKING HIGHS BACK TO MORE SEASONABLE READINGS FOR EARLY DECEMBER /LOWER 60S/. ALTHOUGH SOME ISENTROPIC LIFT WILL BE PRESENT OVER THE CWA LATE SAT NIGHT AND INTO SUN MORNING...MODELS SUGGEST THE GREATEST SATURATION WILL PUSH OFF TO OUR EAST AND NORTHEAST /AS INDICATED BY CONDENSATION PRESSURE DEFICITS/. THEREFORE...THIS EVENT MAY BE WRAPPING UP AFTER MIDNIGHT SUN MORNING FOR MUCH OF NORTH TEXAS...BUT A FEW LINGERING SHOWERS/DRIZZLE MAY BE POSSIBLE. BELIEVE THAT SLIGHT CHANCE POPS TAPERING FROM WEST TO EAST WILL ADDRESS THE UNCERTAINTY FOR NOW. SURFACE HIGH PRESSURE WILL BUILD ACROSS NORTH TEXAS ON TUESDAY...WHILE RISING MID LEVEL HEIGHTS COMMENCE /DUE TO RIDGING ACROSS THE SOUTHWESTERN CONUS/. HIGH TEMPS WILL HOVER IN THE UPPER 60S AND LOWER 70S ON TUES AND WED. MEDIUM RANGE GUIDANCE SUGGESTS THE MID/UPPER LEVEL RIDGE WILL BREAK DOWN MID WEEK...ALLOWING FOR A SHORTWAVE TROF TO DROP INTO THE REGION LATE IN THE WEEK...AND BRING A CHANCE FOR SHOWERS BY NEXT FRIDAY. AT THIS TIME...NO FREEZES ARE EXPECTED FOR NORTH TEXAS OVER THE NEXT SEVERAL DAYS...AS LOW TEMPERATURES WILL GENERALLY STAY IN THE UPPER 30S OR HIGHER THROUGH THE UPCOMING WEEK. HOWEVER...NORTHWEST PORTIONS OF THE CWA MAY HAVE A SHOT AT FROST MONDAY MORNING...AS TEMPERATURES AND DEWPOINTS DROP INTO THE LOWER 30S. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 58 71 64 75 / 10 20 30 20 10 WACO, TX 69 61 72 66 78 / 10 30 30 20 10 PARIS, TX 58 50 69 62 74 / 10 10 30 20 20 DENTON, TX 63 58 71 61 74 / 10 30 30 20 10 MCKINNEY, TX 61 56 69 62 75 / 10 20 30 20 10 DALLAS, TX 65 59 71 64 75 / 10 20 30 20 10 TERRELL, TX 64 57 71 65 76 / 10 10 30 20 20 CORSICANA, TX 67 58 72 65 79 / 10 10 20 20 20 TEMPLE, TX 69 62 72 64 80 / 10 30 30 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 1123 AM CST THU NOV 29 2007 .AVIATION... WIND SPEEDS HAVE ALREADY PICKED UP OUT OF THE SOUTHWEST AS SURFACE TROUGH OVER COLORADO STRENGTHENS. HAVE INCREASED WIND GUST FORECAST SLIGHTLY AS SPEEDS HAVE ALREADY TOPPED 30KTS AT ALL TAF SITES. EXPECT WINDS TO SUBSIDE AFTER SUNSET AND BEGIN SHIFTING MORE OUT OF THE WEST AHEAD OF A COLD FRONT. NUMERICAL MODELS HAVE BEGUN BRINGING THIS FRONT IN MUCH QUICKER THAN PREVIOUSLY THOUGHT. WINDS SHIFT AROUND TO TO THE NORTH AROUND OR SHORTLY AFTER MIDNIGHT FOR KGUY AND KDHT AND THEN BY ABOUT 11Z FOR KAMA. DO NOT EXPECT STRONG WINDS BEHIND THIS FRONT AND HAVE KEPT WINDS FAIRLY LIGHT OUT OF THE NORTHEAST DURING THE MORNING TOMORROW. KIMBLE && .PREV DISCUSSION... /ISSUED 555 AM CST THU NOV 29 2007/ AVIATION... FIRST CONCERN WILL BE THE STRONG SOUTHWEST WINDS THAT SHOULD START LATE THIS MORNING WHEN MIXING STARTS AND PRESSURE GRADIENT TIGHTENS. WINDS SHOULD REACH SPEEDS OF 20 TO 25 KTS WITH HIGHER GUSTS. AFTER SUNSET...SPEEDS SHOULD DIMINISH BEFORE THE NEXT COLD FRONT ENTERS THE SCENE FRIDAY DAYBREAK. NUNEZ PREV DISCUSSION... /ISSUED 522 AM CST THU NOV 29 2007/ DISCUSSION... MAIN FORECAST CONCERN CENTERS ON WINDS TODAY AND PRECIP CHANCES FRI NIGHT AND INTO SAT. RUC UPPER AIR ANALYSIS INDICATES ZONAL FLOW ESTABLISHED OVER THE SOUTHERN PLAINS. THIS WILL PROMOTE A SFC LEE TROUGH TO DEEPEN TODAY WHILE SFC HIGH PRESSURE SCOOTS OFF TO THE EAST. SOUTHERLY WINDS WILL INCREASE TODAY IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. APPEARS THE STRONGEST WINDS WILL LIE OVER THE NORTHWEST PORTION OF THE CWA CLOSEST TO THE BASE OF THE TROUGH AND WHERE THE TIGHTEST PRESSURE GRADIENT LIES. EXPECT WINDS TO COME CLOSE TO ADVISORY LEVELS... HOWEVER HELD OFF ON ISSUING ANY HEADLINES AS NOT EXPECTING SUSTAINED WINDS TO REACH ADVISORY LEVELS. CLOUDS LOOK TO GRADUALLY INCREASE DURING THE DAY WITH HIGHS REACHING GENERALLY IN THE 50S. THIS TROUGH WILL GRADUALLY SLIDE OFF TO THE EAST FRI WITH ITS TRAILING COLD FRONT PUSHING ACROSS THE AREA. WINDS WILL SHIFT TO THE NORTH INITIALLY DELIVERING A QUICK SHOT OF COOLER AIR. MEANWHILE A LOW OFF THE CALIFORNIA BAJA REGION IS FORECAST TO WEAKEN AS IT HEADS TO THE NORTHEAST AND GETS ABSORBED BY THE NORTHERN STREAM FRI NIGHT. COLUMN STARTS TO MOISTEN UP AS WINDS GRADUALLY VEER AROUND TO THE EAST THEN SOUTHEAST BY FRI EVENING. LEFT CHANCE POPS AS IS WITH STRONG WAA PATTERN SETTING IN AND INCREASING LLVL MOISTURE ADVECTION. AGREE WITH INHERITED FCST IN LEAVING THE PRECIP TYPE AS RAIN AS THE 00Z MET GUIDANCE CAME IN WARMER THAN EARLIER RUNS. IN ADDITION SREF GUIDANCE SHOWS SFC TEMPS REMAINING ABOVE FREEZING. SFC LOW THEN CONTINUES TO TRACK TO THE NORTHEAST...INTO THE CENTRAL PLAINS SAT AS A DRY SLOT WORKS IN LATE MORNING SAT. THIS WILL GRADUALLY END ANY PRECIP BY AFTERNOON. SOUTHERLY SFC FLOW WILL INCREASE DURING THE DAY WHICH WILL HELP BOOST TEMPS UP INTO THE 60S. ANOTHER WEAK FRONT IS EXPECTED TO SLIDE ACROSS THE AREA SUN WHILE MAIN SFC LOW PUSHES FURTHER TO THE EAST. TEMPS WILL COOL OFF SLIGHTLY AS ANOTHER QUICK SHOT OF COOLER AIR MOVES ACROSS THE PANHANDLES. UPPER AIR PATTERN LOOKS TO TRANSITION TO THE NORTHWEST WITH RIDGING TAKING PLACE OVER THE SOUTHWEST U.S. FOR MUCH OF THE WEEK. TEMPS WILL GRADUALLY WARM EARLY NEXT WEEK BEFORE ANOTHER FROPA CROSSES THE AREA WED KNOCKING TEMPS BACK TOWARD SEASONAL NORMALS BY THU. CLK FIRE WEATHER... SFC LEE TROUGHING WILL DEVELOP TODAY WITH SOUTHERLY SFC FLOW INCREASING TO 20 TO 30 MPH ESPECIALLY ACROSS THE NORTHWESTERN PORTIONS OF THE TEXAS AND OKLAHOMA PANHANDLES. ALTHOUGH THE FIRE DANGER RATING IS IN THE MODERATE CATEGORY...NOT ANTICIPATING RED FLAG CRITERIA TO BE MET AS RH VALUES ARE EXPECTED TO REMAIN NEAR 20 PERCENT. HOWEVER THE COMBINATION OF THE STRONG WINDS...DRY AIR...AND MINIMUM RH VALUES LESS THAN 30 PERCENT WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS AGAIN ACROSS THE PANHANDLES TODAY. CLK AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. $$ 13/15 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 555 AM CST THU NOV 29 2007 .AVIATION... FIRST CONCERN WILL BE THE STRONG SOUTHWEST WINDS THAT SHOULD START LATE THIS MORNING WHEN MIXING STARTS AND PRESSURE GRADIENT TIGHTENS. WINDS SHOULD REACH SPEEDS OF 20 TO 25 KTS WITH HIGHER GUSTS. AFTER SUNSET...SPEEDS SHOULD DIMINISH BEFORE THE NEXT COLD FRONT ENTERS THE SCENE FRIDAY DAYBREAK. NUNEZ && .PREV DISCUSSION... /ISSUED 522 AM CST THU NOV 29 2007/ DISCUSSION... MAIN FORECAST CONCERN CENTERS ON WINDS TODAY AND PRECIP CHANCES FRI NIGHT AND INTO SAT. RUC UPPER AIR ANALYSIS INDICATES ZONAL FLOW ESTABLISHED OVER THE SOUTHERN PLAINS. THIS WILL PROMOTE A SFC LEE TROUGH TO DEEPEN TODAY WHILE SFC HIGH PRESSURE SCOOTS OFF TO THE EAST. SOUTHERLY WINDS WILL INCREASE TODAY IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. APPEARS THE STRONGEST WINDS WILL LIE OVER THE NORTHWEST PORTION OF THE CWA CLOSEST TO THE BASE OF THE TROUGH AND WHERE THE TIGHTEST PRESSURE GRADIENT LIES. EXPECT WINDS TO COME CLOSE TO ADVISORY LEVELS... HOWEVER HELD OFF ON ISSUING ANY HEADLINES AS NOT EXPECTING SUSTAINED WINDS TO REACH ADVISORY LEVELS. CLOUDS LOOK TO GRADUALLY INCREASE DURING THE DAY WITH HIGHS REACHING GENERALLY IN THE 50S. THIS TROUGH WILL GRADUALLY SLIDE OFF TO THE EAST FRI WITH ITS TRAILING COLD FRONT PUSHING ACROSS THE AREA. WINDS WILL SHIFT TO THE NORTH INITIALLY DELIVERING A QUICK SHOT OF COOLER AIR. MEANWHILE A LOW OFF THE CALIFORNIA BAJA REGION IS FORECAST TO WEAKEN AS IT HEADS TO THE NORTHEAST AND GETS ABSORBED BY THE NORTHERN STREAM FRI NIGHT. COLUMN STARTS TO MOISTEN UP AS WINDS GRADUALLY VEER AROUND TO THE EAST THEN SOUTHEAST BY FRI EVENING. LEFT CHANCE POPS AS IS WITH STRONG WAA PATTERN SETTING IN AND INCREASING LLVL MOISTURE ADVECTION. AGREE WITH INHERITED FCST IN LEAVING THE PRECIP TYPE AS RAIN AS THE 00Z MET GUIDANCE CAME IN WARMER THAN EARLIER RUNS. IN ADDITION SREF GUIDANCE SHOWS SFC TEMPS REMAINING ABOVE FREEZING. SFC LOW THEN CONTINUES TO TRACK TO THE NORTHEAST...INTO THE CENTRAL PLAINS SAT AS A DRY SLOT WORKS IN LATE MORNING SAT. THIS WILL GRADUALLY END ANY PRECIP BY AFTERNOON. SOUTHERLY SFC FLOW WILL INCREASE DURING THE DAY WHICH WILL HELP BOOST TEMPS UP INTO THE 60S. ANOTHER WEAK FRONT IS EXPECTED TO SLIDE ACROSS THE AREA SUN WHILE MAIN SFC LOW PUSHES FURTHER TO THE EAST. TEMPS WILL COOL OFF SLIGHTLY AS ANOTHER QUICK SHOT OF COOLER AIR MOVES ACROSS THE PANHANDLES. UPPER AIR PATTERN LOOKS TO TRANSITION TO THE NORTHWEST WITH RIDGING TAKING PLACE OVER THE SOUTHWEST U.S. FOR MUCH OF THE WEEK. TEMPS WILL GRADUALLY WARM EARLY NEXT WEEK BEFORE ANOTHER FROPA CROSSES THE AREA WED KNOCKING TEMPS BACK TOWARD SEASONAL NORMALS BY THU. CLK FIRE WEATHER... SFC LEE TROUGHING WILL DEVELOP TODAY WITH SOUTHERLY SFC FLOW INCREASING TO 20 TO 30 MPH ESPECIALLY ACROSS THE NORTHWESTERN PORTIONS OF THE TEXAS AND OKLAHOMA PANHANDLES. ALTHOUGH THE FIRE DANGER RATING IS IN THE MODERATE CATEGORY...NOT ANTICIPATING RED FLAG CRITERIA TO BE MET AS RH VALUES ARE EXPECTED TO REMAIN NEAR 20 PERCENT. HOWEVER THE COMBINATION OF THE STRONG WINDS...DRY AIR...AND MINIMUM RH VALUES LESS THAN 30 PERCENT WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS AGAIN ACROSS THE PANHANDLES TODAY. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 08/05 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 522 AM CST THU NOV 29 2007 .DISCUSSION... MAIN FORECAST CONCERN CENTERS ON WINDS TODAY AND PRECIP CHANCES FRI NIGHT AND INTO SAT. RUC UPPER AIR ANALYSIS INDICATES ZONAL FLOW ESTABLISHED OVER THE SOUTHERN PLAINS. THIS WILL PROMOTE A SFC LEE TROUGH TO DEEPEN TODAY WHILE SFC HIGH PRESSURE SCOOTS OFF TO THE EAST. SOUTHERLY WINDS WILL INCREASE TODAY IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. APPEARS THE STRONGEST WINDS WILL LIE OVER THE NORTHWEST PORTION OF THE CWA CLOSEST TO THE BASE OF THE TROUGH AND WHERE THE TIGHTEST PRESSURE GRADIENT LIES. EXPECT WINDS TO COME CLOSE TO ADVISORY LEVELS... HOWEVER HELD OFF ON ISSUING ANY HEADLINES AS NOT EXPECTING SUSTAINED WINDS TO REACH ADVISORY LEVELS. CLOUDS LOOK TO GRADUALLY INCREASE DURING THE DAY WITH HIGHS REACHING GENERALLY IN THE 50S. THIS TROUGH WILL GRADUALLY SLIDE OFF TO THE EAST FRI WITH ITS TRAILING COLD FRONT PUSHING ACROSS THE AREA. WINDS WILL SHIFT TO THE NORTH INITIALLY DELIVERING A QUICK SHOT OF COOLER AIR. MEANWHILE A LOW OFF THE CALIFORNIA BAJA REGION IS FORECAST TO WEAKEN AS IT HEADS TO THE NORTHEAST AND GETS ABSORBED BY THE NORTHERN STREAM FRI NIGHT. COLUMN STARTS TO MOISTEN UP AS WINDS GRADUALLY VEER AROUND TO THE EAST THEN SOUTHEAST BY FRI EVENING. LEFT CHANCE POPS AS IS WITH STRONG WAA PATTERN SETTING IN AND INCREASING LLVL MOISTURE ADVECTION. AGREE WITH INHERITED FCST IN LEAVING THE PRECIP TYPE AS RAIN AS THE 00Z MET GUIDANCE CAME IN WARMER THAN EARLIER RUNS. IN ADDITION SREF GUIDANCE SHOWS SFC TEMPS REMAINING ABOVE FREEZING. SFC LOW THEN CONTINUES TO TRACK TO THE NORTHEAST...INTO THE CENTRAL PLAINS SAT AS A DRY SLOT WORKS IN LATE MORNING SAT. THIS WILL GRADUALLY END ANY PRECIP BY AFTERNOON. SOUTHERLY SFC FLOW WILL INCREASE DURING THE DAY WHICH WILL HELP BOOST TEMPS UP INTO THE 60S. ANOTHER WEAK FRONT IS EXPECTED TO SLIDE ACROSS THE AREA SUN WHILE MAIN SFC LOW PUSHES FURTHER TO THE EAST. TEMPS WILL COOL OFF SLIGHTLY AS ANOTHER QUICK SHOT OF COOLER AIR MOVES ACROSS THE PANHANDLES. UPPER AIR PATTERN LOOKS TO TRANSITION TO THE NORTHWEST WITH RIDGING TAKING PLACE OVER THE SOUTHWEST U.S. FOR MUCH OF THE WEEK. TEMPS WILL GRADUALLY WARM EARLY NEXT WEEK BEFORE ANOTHER FROPA CROSSES THE AREA WED KNOCKING TEMPS BACK TOWARD SEASONAL NORMALS BY THU. CLK && .FIRE WEATHER... SFC LEE TROUGHING WILL DEVELOP TODAY WITH SOUTHERLY SFC FLOW INCREASING TO 20 TO 30 MPH ESPECIALLY ACROSS THE NORTHWESTERN PORTIONS OF THE TEXAS AND OKLAHOMA PANHANDLES. ALTHOUGH THE FIRE DANGER RATING IS IN THE MODERATE CATEGORY...NOT ANTICIPATING RED FLAG CRITERIA TO BE MET AS RH VALUES ARE EXPECTED TO REMAIN NEAR 20 PERCENT. HOWEVER THE COMBINATION OF THE STRONG WINDS...DRY AIR...AND MINIMUM RH VALUES LESS THAN 30 PERCENT WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS AGAIN ACROSS THE PANHANDLES TODAY. CLK && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 60 34 52 42 67 / 0 0 10 50 30 BEAVER OK 58 27 47 35 62 / 0 0 5 50 30 BOISE CITY OK 57 29 46 37 62 / 0 0 10 50 30 BORGER TX 59 36 54 44 65 / 0 0 5 50 30 BOYS RANCH TX 60 33 50 42 66 / 0 0 10 50 30 CANYON TX 59 34 52 43 67 / 0 0 10 50 30 CLARENDON TX 59 35 53 42 66 / 0 0 5 50 30 DALHART TX 60 30 48 39 63 / 0 0 10 50 30 GUYMON OK 58 29 49 39 64 / 0 0 5 50 30 HEREFORD TX 59 34 52 43 66 / 0 0 10 50 30 LIPSCOMB TX 58 29 49 37 62 / 0 0 5 50 30 PAMPA TX 58 35 53 42 64 / 0 0 5 50 30 SHAMROCK TX 58 36 54 41 65 / 0 0 5 50 30 WELLINGTON TX 59 37 54 44 67 / 0 0 5 50 30 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 08/05 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 958 PM MST FRI NOV 30 2007 .UPDATE... WILL DROP FZRA ADVISORY FOR EL PASO COUNTY...AS ONLY VERY LIGHT PRECIP IS EXPECTED. WILL LOWER SNOW AMOUNTS FOR MUCH OF THE EASTERN MOUNTAINS AS ABOVE FREEZING AIR IS FAIRLY EXTENSIVE WEST OF I-25. PETERSEN && .PREV DISCUSSION... /ISSUED 827 PM MST FRI NOV 30 2007/ UPDATE... LATEST SATELLITE/RADAR/SURFACE OBS SUGGEST MODERATE TO HEAVY PRECIPITATION WAS SPREADING INTO MOST MOUNTAIN AND WESTERN VALLEY ZONES AS OF 03Z...WITH VERY HIGH FREEZING LEVELS (AROUND 10K FEET) KEEPING SNOW LIMITED TO MAINLY HIGHER ELEVATION ZONES. QUICK LOOK AT NEW 00Z NAM SUGGESTS FORECAST FOR MOUNTAIN ZONES/WRN VALLEYS IS MOSTLY ON TRACK...THOUGH SNOW AMOUNTS FOR LOWER ELEVATION ZONES MAY BE OVERDONE AS A GOOD DEAL OF RAIN WILL FALL OVERNIGHT BEFORE MID LEVEL TEMPS COOL SATURDAY AFTERNOON AND CHANGE PRECIP BACK TO SNOW. WILL KEEP CURRENT GROUP OF MOUNTAIN HIGHLIGHTS INTACT...BUT WILL SCALE BACK SNOW ACCUMS IN AREAS BELOW 10K FEET MSL. EASTERN PLAINS FORECAST MUCH LESS CLEAR-CUT...AS NEW NAM HAS LITTLE TO NO PRECIP ALONG AND EAST OF I-25 THROUGH THE NIGHT. ALREADY UPDATED ONCE TO TRIM BACK POPS BEFORE MIDNIGHT...MAY NEED TO CUT BACK AGAIN IF NAM IS ANYWHERE CLOSE TO CORRECT. WILL LET CURRENT ZR ADVISORY RUN FOR NOW... BUT AM SERIOUSLY CONTEMPLATING DROPPING IT FOR ALL ZONES LATER THIS EVENING IF PRECIP IS SLOW TO DEVELOP. 10 PREV DISCUSSION... /ISSUED 221 PM MST FRI NOV 30 2007/ SHORT TERM... (TONIGHT AND SATURDAY) .COMPLEX WEATHER PATTERN OVER THE NEXT 24-36 HOURS... .FEET OF SNOW FOR THE SOUTHWEST/CENTRAL MOUNTAINS... .WINTRY MIX STILL POSSIBLE PARTS OF SOUTHEAST CO TONIGHT... .STRONG/DAMAGE HIGH WIND THREAT SOUTHEAST CO SATURDAY... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED THE OPENING SUB-TROPICAL WEATHER SYSTEM JUST OFF THE CA BAJA MOVING EAST THANKS TO AN UPPER LEVEL JET STREAM AND ASSOCIATED DIGGING TROUGH MOVING JUST OFF THE CA COAST. IN RETURN...VERY DEEP SOUTHWEST FLOW AND HIGH MOISTURE CONTENT AIR WAS STREAMING ACROSS OLD MEXICO...THE DESERT SOUTHWEST INTO UT/CO. 12Z/30 OBS SOUNDINGS ACROSS SOUTHERN CA...AZ...NM...AND SOUTHWEST TX HAD PRECIPITABLE WATER INDICES OF 150-315 PERCENT ABOVE NORMAL VALUES THIS TIME OF THE YEAR...1.19 INCHES AT TUCSON...AZ. 700MB-500MB SPECIFIC HUMIDITY VALUES ARE AROUND 5G/KG...WHICH IS A FAIRLY TROPICAL AIR MASS AND SOMETHING WE SEE AROUND HERE DURING THE SUMMER "MONSOON." GIVEN THE RELATIVELY STRONG MOISTURE TRANSPORT...BANDS OF SHOWERS HAVE BEEN FORMING ACROSS UT...WESTERN CO...AND NM. THERE HAS BEEN SOME PERIODIC SNOWFALL ACROSS THE HIGH TERRAIN PER SPOTTERS...OBS...AND LIVE WEBCAMS. WARM AIR ALOFT ALREADY BUILDING AS LA VETA PASS SENSOR STARTED IN THE 20S THIS MORNING AND MANAGED TO WARM INTO THE MIDDLE 30S DURING SOME PRECIPITATION. THE BOSQUE RAWS IN THE EAST SIDE THE SOUTHERN SANGRE DE CRISTO MOUNTAINS AROUND 8K FT MSL WAS IN THE LOWER 50S...GOTTA LOVE CO COMPLEX TERRAIN. WE RECEIVED A SPOTTER REPORT OF 1.5 INCHES OF SNOW 5 ESE FORT GARLAND(8500 FEET MSL) AND THAT WAS IN ABOUT 6 HOURS. EARLY THIS AFTERNOON...MOST LIVE WEBCAMS(WOLF CREEK PASS...MONARCH PASS...SAN LUIS VALLEY) LOOK RELATIVELY SNOWFALL-FREE. MEANWHILE...S51OW CP AIR MASS WAS ACROSS EASTERN CO INTO THE CENTRAL/SOUTHERN PLAINS. TEMPERATURES ARE STRUGGLING TO WARM IN THE LOWER AR RIVER VALLEY AND MAY NOT MAKE IT INTO THE 30S AROUND LAMAR. SURFACE WINDS WERE ALREADY VEERING TO THE SOUTH-SOUTHEAST ALONG I-25 CORRIDOR AND EASTWARD WITH DEW POINTS IN THE TEENS. FOR THE MOUNTAINS/HIGH VALLEYS LATE THIS AFTERNOON THROUGH SATURDAY...QUITE THE ARRAY OF WEATHER ACROSS MUCH OF CO GIVEN THE VERY COMPLEX AND C51ENGING WEATHER PATTERN. GIVEN THE DEEP MOISTURE FLUX COMBINED WITH ISENTROPIC ASCENT TONIGHT AND OROGRAPHIC ASCENT FOR SOME FAVORED AREAS...SNOW SHOWERS SHOULD BECOME MORE STEADY SNOW...HEAVY AT TIMES...ACROSS THE MOUNTAINS AND HIGH VALLEYS ESPECIALLY FOR THE SAN JUAN...LA GARITA...COLLEGIATE... AND SANGRE DE CRISTO MOUNTAIN RANGES. STILL LOOKS LIKE THE HEAVIEST SNOW WILL BE GENERALLY ABOVE 8K FT MSL...ESPECIALLY AROUND THE MOUNTAIN PEAKS/HIGH MOUNTAIN PASSES. 1-4 FEET STILL LOOKS DOABLE AROUND THE CENTRAL AND SOUTHERN PORTION OF THE CONTINENTAL DIVIDE. LESSER AMOUNTS AS YOU HEAD TO THE LOWER ELEVATIONS. WENT AHEAD AND ADDED ADVISORIES FOR THE LOWER ELEVATIONS OF THE WEST SIDE OF THE CONTINENTAL DIVIDE IN SAGUACHE COUNTY/LA GARITA MOUNTAINS TOWARD THE GUNNISON VALLEY AND THE REST OF LAKE COUNTY INCLUDING LEADVILLE. OTHER LOWER MOUNTAIN VALLEY/HIGH VALLEYS LIKE SAN LUIS AND UPPER AR SHOULD SEE SOME ACCUMULATING LIGHT SNOW...BUT BELOW ADVISORY VALUES. THE SNOW LIKELY ENDS FOR THE SANGRE DE CRISTO/WET/PIKE PIKE MOUNTAINS GIVEN RELATIVELY STRONG ISENTROPIC DOWNGLIDE AS MODERATE-STRONG MIDLEVEL TO SURFACE WINDS DEVELOP. HOWEVER...OROGRAPHIC ASCENT DRIVEN SNOW SHOULD CONTINUE ACROSS THE CONTINENTAL DIVIDE. FOR THE I-25 CORRIDOR AND SOUTHEAST CO PLAINS LATE THIS AFTERNOON THROUGH SATURDAY...VERY TOUGH CALL IN WHAT WILL ACTUALLY OCCUR. STAYED CLOSE TO CURRENT FORECAST GIVEN A NUMBER OF UNCERTAINTIES. IN RESPONSE TO THE CP AIR MASS POSSIBLY RECEDING EASTERN CO AND WARM AIR ADVECTION ALOFT...SURFACE PRESSURE FALLS INCREASE THROUGH THE NIGHT. 295K/300K ISENTROPIC ASCENT DEVELOPS ACROSS MUCH OF NM...EASTERN CO...AND ESPECIALLY KS/OK/TX. TOUGH TO TRULY SAY WHERE THE WARM FRONT WILL BE LOCATED AS ANY PRECIPITATION EVAPORATIVE OR DIABATIC COOLING COULD KEEP THE S51OW COLD AIR LOCKED INTO THE LOWER AR RIVER VALLEY WHILE THE WARM AIR BUILDS OVER EASTERN CO. IF THAT IS THE CASE...THEN THERE STILL COULD BE A WINTRY MIX THIS EVENING AND OVERNIGHT GENERALLY EAST OF I-25 CORRIDOR AND NOT FOR THE RATON MESA OR PALMER DIVIDE GIVEN THE HIGHER TERRAIN. NAM-WRF 12KM SOUNDING FOR EADS HAS A FREEZING RAIN VERTICAL THERMAL PROFILE. HOWEVER...IF THE PRECIPITATION HAS TROUBLES MATERIALIZING...OR INCREASING IN INTENSITY...THEN THE WARM SOUTHERLY WIND COULD TAKE OVER. BOTH THE GFS AND NAM-WRF MOS GUIDANCE HAVE CONSISTENTLY WARM TEMPERATURES IN THE 30S AND 40S THROUGH THE NIGHT TONIGHT. GIVEN THE UNCERTAINTIES...THIS IS WHY I STUCK WITH THE CURRENT FORECAST. IF THERE IS A WINTRY MIX ACROSS PARTS OF EL PASO COUNTY TO KIOWA/PROWERS COUNTIES...THEN IT WILL BE SHORT-LIVED AS VIGOROUS SOUTH-SOUTHWEST LOWER TROP WINDS DEVELOP EARLY SATURDAY MORNING. 45-70KTS AROUND 800MB-700MB DEVELOPS ACROSS SOUTHEAST CO SATURDAY. POTENTIAL WIND GUSTS UP TO 60 MPH WILL BE LIKELY IF THE SURFACE PRESSURE GRADIENT CAN TIGHTEN LIKE THE GFS...BUT THE NAM-WRF IS A LITTLE WEAKER. SINCE IT WILL BE CLOSE...PLAN TO GO AHEAD WITH A HIGH WIND WARNING ACROSS SOUTHEAST CO PLAINS AND GOES WELL WITH ABQ/AMA WARNING. STILL A LITTLE CONCERNED ABOUT MAX TEMPERATURES ACROSS SOUTHEAST CO SATURDAY. WE ARE STILL ROUGHLY 10-15 DEGREES BELOW MOS GUIDANCE WITH DEEP VIGOROUS SOUTHWEST-WEST DOWNSLOPE FLOW. STAYED THE COURSE GIVEN SURROUNDING OFFICES. ONE FINAL POTENTIAL IMPACT ISSUE IS FIRE WEATHER CONCERNS GIVEN THE WINDY TO STRONG WIND CONDITIONS ACROSS THE SOUTHEAST CO PLAINS. FUELS ARE AT CRITICAL LEVELS ACROSS THIS AREA...TEMPERATURES WILL BE ABOVE AVERAGE READINGS...BUT HUMIDITY VALUES ARE NOT FORECAST TO BE BELOW 20 PERCENT. GIVEN THE COMPLEX WEATHER PATTERN ALREADY OCCURRING...WILL FORGO THE FIRE WEATHER HEADLINES. 17 LONG TERM... (SATURDAY NIGHT THROUGH FRIDAY) LATEST LONGER TERM MODELS INDICATE THAT UPPER SYSTEM CONTINUES TO IMPACT REGION FROM SATURDAY NIGHT INTO SUNDAY MORNING WITH IMPROVING METEOROLOGICAL CONDITIONS RETURNING TO THE CWFA FROM LATER SUNDAY INTO EARLY WEDNESDAY. ANOTHER UPPER SYSTEM IS PROJECTED TO BRING UNSETTLED WEATHER CONDITIONS TO THE AREA FROM WEDNESDAY INTO NEXT FRIDAY. FOR SENSIBLE WEATHER...HAVE PAINTED SNOW...HEAVY AT TIMES...TO CONTINUE OVER PORTIONS OF ZONES 58/59/60/61/68 AND 75 ON SATURDAY NIGHT WITH PRECIPITATION DECREASING SUNDAY. IN ADDITION...HAVE CONTINUED TO PAINT RELATIVELY STRONG WINDS OVER THE CWFA FROM SATURDAY NIGHT INTO AT LEAST SUNDAY MORNING. GENERALLY DRY AND WARMER CONDITIONS EXPECTED TO DEVELOP OVER THE REGION MONDAY AND TUESDAY WITH COOLER AND UNSETTLED CONDITIONS THEN RETURNING AGAIN TO SOUTHERN COLORADO FROM LATER WEDNESDAY INTO NEXT FRIDAY. AVIATION...BASED ON THE SHORT TERM DISCUSSION...THE PREVIOUS DISCUSSION LOOKS ON TARGET. MVFR CONDITIONS SHOULD DEVELOP AT THE THREE SITES FROM 00Z TO 02Z. KALS WILL SEE SOME LIGHT SNOW...AND KCOS SOME LIGHT SNOW...SLEET...THEN FREEZING RAIN AFTER 07Z. KPUB WILL LIKELY SEE PERIODS FOR RAIN...SLEET...SNOW...WITH A CHANCE OF A BRIEFLY PERIOD OF FREEZING RAIN FOR A FEW HOURS IN THE MIDDLE OF THE NIGHT. WINDY CONDITIONS WILL AFFECT ALL TAF LOCATIONS SATURDAY. TLM/17 PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ093>099. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MST SATURDAY FOR COZ0095-096-098. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ067. PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MST SATURDAY FOR COZ058-059. HIGH WIND WARNING FROM 6 AM TO 6 PM MST SATURDAY FOR COZ093>099. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM MST SATURDAY FOR COZ084-085-095-096-098. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST SATURDAY FOR COZ064. SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM MST SATURDAY FOR COZ067. $$ && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MST SATURDAY FOR COZ058-059. HIGH WIND WARNING FROM 6 AM TO 6 PM MST SATURDAY FOR COZ093>099. FREEZING RAIN ADVISORY UNTIL 6 AM MST SATURDAY FOR COZ095-096- 098. WINTER STORM WARNING UNTIL 12 PM MST SATURDAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MST SATURDAY FOR COZ064. SNOW AND BLOWING SNOW ADVISORY UNTIL 12 PM MST SATURDAY FOR COZ067. && $$ 10/28 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 102 AM EST SAT DEC 1 2007 .AVIATION... THIS ISSUANCE OF THE TAFS ARE FAIRLY QUIET UNTIL TOWARDS THE END OF THE TAF PERIOD. THE BEGINNING OF TODAY WILL SEE HIGH PRESSURE MOVING ON TO THE EAST. AS THIS OCCURS...AN APPROACHING SYSTEM FROM THE WEST WILL BEGIN TO BUNCH OF THE PRESSURE GRADIENT...CAUSING THE WIND TO BEGIN TO INCREASE IN SPEED FROM THE SOUTHEAST ROUGHLY MID MORNING. THEN THROUGH MIDDAY AND THE AFTERNOON THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN...CONTINUING TO INCREASE THE WIND SPEED AND BECOME GUSTY OVER BY SBN. ALSO IN THE AFTERNOON HOURS THE CEILING WILL BE LOWERING BUT STILL VFR. THEN WITH A WARM FRONT APPROACHING AND MOVING IN DURING THE LATE AFTERNOON HOURS INTO THE EVENING...WILL BRING A WINTER MIX OF PRECIP TO THE AIRPORTS. SOONER AT SBN THEN AT FWA. THIS WINTER MIX OF PRECIP IS TOWARDS THE END OF THE TAFS...BUT AT THIS POINT SBN IS LOOKING TO AT LEAST DROP INTO MVFR CONDITIONS WITH A LITTLE BIT SMALLER CHANCE THAT FWA WILL BY 06Z SUNDAY. LATER TAF ISSUANCES WILL GET A BETTER LOOK AT THIS COMING EVENING/NIGHTTIME FRAME IF CONDITIONS WILL INDEED DROP MORE THAN MVFR OR NOT. && .PREV DISCUSSION... /ISSUED 428 PM EST FRI NOV 30 2007/ SHORT TERM...TONIGHT AND SATURDAY. FAST MOVING LOW PRESSURE IS IN THE PROCESS OF EXITING THE REGION. COLD FRONT ASSOCIATED WITH THIS SYSTEM HAS CLEARED THE FA AND VIGOROUS COLD AIR ADVECTION ALONG WITH STAGGERING NEGATIVE THETA-E ADVECTION IS ONGOING PER ADVANCING SFC HIGH PRESSURE. LAKE EFFECT CLOUDS ARE TRYING TO HANG ON OVER THE NORTHERN ZONES. HOWEVER...EXTREMELY DRY AIR FROM THE ADVECTING CP AIRMASS IS LIMITING THIS PROCESS. TEMPERATURES ARE IN THE PROCESS OF FALLING INTO THE 20S NORTHWEST WITH LOWER 40S STILL PRESENT OVER THE SE. FARTHER UPSTREAM....DIGGING UPPER TROUGH OVER THE EASTERN PACIFIC IS BEGINNING TO MAKE LANDFALL OVER NORTHERN CA. PHASING BETWEEN THIS SYSTEM AND THE WEST BAJA UPPER TROUGH WILL PRODUCE VAST LARGE SCALE ASCENT AS THESE SYSTEMS EJECT OUT INTO THE PLAINS BY TOMORROW...SUPPORTING THE DEVELOPMENT OF DEEP LOW PRESSURE OVER THE CENTRAL US. TONIGHT...STRONG SFC HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION OVERNIGHT. WINDS WILL DROP OFF AFTER MIDNIGHT. WITH EXTREMELY DRY AIR IN PLACE/LIGHT WINDS/AND MOSTLY CLEAR SKIES SAVE INCREASING CIRRUS SHIELD PER HEIGHT RISES...EXPECTING A COLD NIGHT TONIGHT WITH LOWS IN THE TEENS ANTICIPATED. WOULD NOT BE SURPRISED IF A FEW ARES IN THE NORTHEAST DROP INTO THE SINGLE DIGITS. TRAJECTORY ANALYSIS INDICATES ADVECTING AIR MASS HAS ALREADY PRODUCED LOWS BELOW ZERO UPSTREAM OVER THE DAKOTAS EVEN WHERE SNOW WAS ABSENT. SATURDAY...MID AND HIGH CLOUDS WILL BE ON THE INCREASE AS LOW PRESSURE DEEPENS OVER THE PLAINS...FORCING THETA-E ADVECTION. VERY DRY AIR WILL BE IN PLACE IN THE LOWER LEVELS. FORECAST MODELS INDICATE A DEWPOINT OF -40C AT H85 12Z SATURDAY. STRONG SUBSIDENCE PER ADVANCING HIGH PRESSURE WILL ACT TO FURTHER DRY THIS LAYER INTO THE EARLY AFTERNOON. GFS/ECWMF/AND GEM ALL INDICATE LIGHT PRECIP MOVING INTO REGION PER ISENTROPIC UPGLIDE/THETA-E ADVECTION. NAM/WRF CONFINES ALL PRECIP WEST OF THE FA. IN EXAMINING NMM AND RUC 13 SIM REFLECTIVITY...IT IS OBVIOUS THAT PRECIP INTENSITY IS WEAK AND HIGHEST RETURNS ARE NW OF THE FA. GIVEN STAGGERING AMOUNT OF DRY AIR IN PLACE AND ESE LOW LEVEL FLOW REINFORCING DRY SUBCLOUD AIR...HAVE CONTINUED TO FAVOR THE NAM/WRF SOLUTION AS IT IS THE SLOWEST TO ERODE THE DRY SUB CLOUD LAYER IN PLACE. THIS MAKES THE MOST SENSE GIVEN MAIN UPPER IMPULSE AND ASSOCIATE LARGE SCALE ASCENT WILL BE WELL WEST OF THE REGION OVER THE PLAIN STATES UNTIL THE EVENING. HENCE...FORCING AND ANY SYMMETRIC INSTABILITY WILL BE WEAK THROUGH THE PERIOD. HAVE DROPPED POPS TO LIKELY NW...WITH CHANCE EVERY ELSE. BEST PRECIP CHANCES STILL RESIDE IN THE NORTHWEST LATE IN THE AFTERNOON. GIVEN EXPECTED WEAK FORCING...THINKING ANY PRECIP WILL BE ON THE LIGHT SIDE WITH THIS FIRST WAVE OF ASCENT. RETAINED SNOW SLEET MENTION NORTH...WITH RAIN/ZR/SLEET IN THE SOUTH PER TOP DOWN ANALYSIS. WITH ANTICIPATED LOW IMPACT AFTERNOON PRECIP...HAVE MOVED WATCH TO 00Z PER COORDINATION WITH SURROUNDING WFOS. LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. SHRTWV DIGGING SOUTH ALONG WEST COAST THIS AFTN. IN RESPONSE, CUT-OFF UPPER LOW OFF BAJA WAS OPENING UP AND LIFTING NE. SUB-TROPICAL MOISTURE SEEN ON WATER VAPOR LOOPS STREAMING NORTHWARD ACROSS MEXICO INTO SWRN U.S. IN ADVANCE OF THIS SYSTEM. GULF MOISTURE SHOULD ALSO BE TAPPED AS SFC SYSTEM MOVES INTO PLAINS ON SAT. MODELS IN DECENT AGREEMENT THAT SFC LOW WILL TRACK NE FROM KS/NEB SAT EVE TO NRN LWR MI SUN EVE. STRONG WARM FRONT SE OF TRACK OF SFC LOW EXPECTED TO MOVE THROUGH THE CWA SAT NGT AND SUN MORNING. WARM/MOIST AIR BEING LIFTED OVER THE FRONT SHOULD RESULT IN WIDESPREAD PCPN SAT NGT. AS FOR PRECIP TYPE... APPEARS WILL BE COLD ENOUGH ALOFT AND DRY ENOUGH IN LOW LEVELS FOR ONSET TO BE MAINLY SNOW/SLEET ACROSS THE ENTIRE CWA. STRONG WAA BETWEEN 5K-10K FT SHOULD QUICKLY CHANGE THE SNOW/SLEET MIX TO A FREEZING RAIN/SLEET MIX. GENERALLY FOLLOWED NAM QPF FIELDS WHICH SUGGESTS POTENTIAL FOR A QUARTER TO HALF INCH OF PRECIP SAT NGT. ALSO SLOPED FGEN FORCING FCST CONSISTENTLY BY MODELS COULD LEAD TO SOME HEAVIER BANDS AS STRONG WAA ALOFT MOVES INTO THE AREA. POTENTIAL FOR QUARTER INCH OF GLAZE STILL APPEARS SUFFICIENT TO LEAVE WATCH UP FOR SAT NGT ACROSS NRN CWA AND EARLY SUNDAY NE. AS LOW PASSES TO OUR NORTH ON SUNDAY WAA WILL RAISE TEMPS IN THIS AREA WELL ABOVE FREEZING ON SUNDAY. LEANED TOWARD COOLER MAV NORTH WHERE MELTING ICE SHOULD HOLD TEMPS DOWN...WHILE GENERALLY SPLIT MAV/MET DIFFERENCE ACROSS SOUTH. COLD FRONT ASSOCIATED WITH THE SFC LOW IS EXPECTED TO SWEEP EAST ACROSS THE AREA SUNDAY EVE. LAST COUPLE RUNS OF THE NAM HAVE BEEN INDICATING WK INSTABILITY DEVELOPING OVER SRN PORTIONS OF CWA AHEAD OF THE COLD FRONT. FOR NOW CONTD WITH SHOWERS BUT MAY NEED TO CONSIDER ADDING TSTMS TO THIS AREA IF MODELS PERSIST WITH THIS SOLUTION. WRAP AROUND AND LAKE EFFECT SNOW SHOWERS SHOULD LINGER INTO MON NGT. CLIPPER SYSTEM EXPECTED TO MOVE THROUGH TUE AFTN/NIGHT WITH SOME LINGERING LAKE EFFECT IN THE WAKE OF THIS SYSTEM WED NGT. RIDGING EXPECTED TO END THIS ACTIVITY THU, BUT ANOTHER SHRTWV AND WAA ON BACKSIDE OF THE RIDGE MAY SPREAD SOME RN/SN INTO THE AREA ON FRI. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR INZ006-007. WINTER STORM WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR INZ003>005-008-009. MI...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR MIZ079>081. WINTER STORM WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR MIZ077-078. OH...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR OHZ001-002. LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...TAYLOR AVIATION...LOTHAMER in AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1208 AM CST SAT DEC 1 2007 .UPDATED FOR 06Z AVIATION... .SHORT TERM...TONIGHT THROUGH SUNDAY 19Z SFC ANLYS INDICATED 1035 MB HIGH OVER NW IOWA WITH BROADER EXTENT OF SURFACE HIGH INTO KANSAS AND MO. COLD AIR AT 850 HAS PUSHED SOUTH OF IOWA INTO MO AND KS AS WELL...WITH MUCH COLDER AIR IN THE BOUNDARY LAYER. AS HIGH RETREATS EAST OF THE AREA OVERNIGHT...A SLIGHT GRADIENT WILL DEVELOP OVER WESTERN IOWA WITH WEAK WARM AIR ADVECTION BEGINNING AFTER 06Z. WITH THIS IN MIND HAVE PLACED LOW TEMPS RIGHT AROUND MIDNIGHT WITH NEAR STEADY TEMPS OVER THE FAR NORTH WHERE A LIGHT SNOWFIELD NOW EXITS ALONG THE HIGHWAY 9 CORRIDOR. AS TEMPS WARM IN THE WEST TOWARD MORNING...SO WILL AN INCREASE IN CLOUDS FROM ADVANCING SYSTEM AND A SWITCH TO A SOUTHERLY WIND COMPONENT. WEAK THETA-E ADVECTION HAS ALREADY BEGUN TO THE NW OF THE AREA...HOWEVER QUITE RELATIVE AND STILL THINK SOME RADIATIONAL COOLING WILL WIN OUT IN THE EVENING HOURS ACROSS THE NORTH. HAVE BASICALLY USED AND ADJUSTED RUC FORECAST FOR TONIGHT. WAA ADVECTION IN THE MID AND LOWER LAYERS WILL BE RAPIDLY INTENSIFYING BY THE END OF TONIGHT SO HAVE 20 PERCENT CHCS OF PCPN THROUGH ABOUT A DNS-LWD LINE THROUGH 9 AM WITH 50 POPS ACROSS THE EXTREME SOUTHWEST COUNTIES BY 12Z (6AM) SATURDAY. INITIAL PCPN BURST WILL BE SNOW AND SLEET. SITUATION LOOKS TO DETERIORATE QUICKLY SAT MORNING. MODELS IN GOOD AGREEMENT WITH FORCING AND QPF...BUT LOW LEVEL TEMPERATURE DETAILS ARE MOST PROBLEMATIC AND UNFORTUNATELY THE KEY TO THE FORECAST. ALTHOUGH 18Z RUN HAS WARMED SOMEWHAT...12Z NAM WAS ON COOL END OF THERMAL ENVELOPE AND SEEMS TO BE AN OUTLIER. CONSIDERING THE STRENGTH OF WARM ADVECTION AND POTENTIAL LATENT HEAT RELEASE WITH FREEZING RAIN...FEEL THE NAM IS TOO COOL AND NOT AGGRESSIVE ENOUGH WITH PRESSURE FALLS INTO MO VALLEY. ALTHOUGH IT IS NOT DEPICTED IN THE FORECAST TO KEEP THINGS SIMPLER...WOULD NOT BE SURPRISED TO SEE CONVECTION EITHER WHOSE LATENT HEAT WOULD CAUSE SIMILAR WARMER RESULTS. WITH THIS IN MIND...THE FORECAST GENERALLY FOLLOWED 09Z SREF SFC TEMPS/DEWPOINTS AND GFS FORCING WHICH SEEMED TO BE A NICE COMPROMISE BETWEEN THE COOL NAM AND CONTINUALLY WARM END ECMWF. MODELS TYPICALLY UNDERESTIMATE STRONG COOLING WHICH WE HAVE IN PLACE NOW...AND ALSO STRONG WAA SO WARMER END OF FORECAST SOLUTIONS WILL HAVE TO BE WATCHED DURING TRANSITION. IN MORE DETAIL...FORCING REALLY INCREASES SAT MORNING AS SWRN TROUGH EJECTS INTO THE CENTRAL PLAINS. EARLY ON UVM IS MAINLY DRIVEN BY THERMODYNAMICS WITH ABOUT 12 HOURS OF THETA-E ADVECTION AND FRONTOGENETICAL FORCING ON BACK EDGE. THIS SHOWS UP QUITE WELL IN 290-300K ISENT LAYER WITH PROLONGED AND IMPRESSIVE MOISTURE TRANSPORT AND UVM. KINEMATIC FORCING ALSO INCREASES AROUND 00Z WHEN PARENT SHRT WV LIFTS THROUGH. THIS COULD VERY WELL TURN INTO AN EXTREME ICE STORM EVENT IN THE NRN HALF OF THE STATE WITH QPF AMOUNTS HOVERING AROUND AN INCH...AND THIS MAKES SENSE WITH PWS PUSHING RECORD VALUES. THE PCPN WILL SWITCH TO RAIN SOUTH AND HOPEFULLY ALLEVIATE A PROLONGED EVENT THERE. HAVE SWITCHED WATCH TO WINTER STORM WARNING NORTH WHERE SNOW WILL FALL INITIALLY...CAPPED WITH SIGNIFICANT SLEET AND FREEZING RAIN ACCUMS. WITH SURGE OF WARM LAYER AND RELATIVELY LOW SNOW RATIOS...SNOW POTENTIAL WILL NOT LAST TOO LONG BUT MAY DROP 1-5 INCH SNOWS WITH MAX ALONG MN BORDER. CENTRAL AND SOUTH CLIPPED LENGTH OF HEADLINE SWITCHING TO ICE STORM WARNING WHERE PCPN SHOULD MAINLY BE LIQUID BEFORE TEMPS APPROACH OR EXCEED FREEZING. ALTHOUGH APPRECIABLE PCPN MAY NOT FALL IN NRN PORTIONS AFTER 03Z...EVEN LIGHT RAIN OR FREEZING DRIZZLE MAY CONTINUE TO CAUSE PROBLEMS AND ACCUMULATE SO HAVE KEEP WARNING TIL 12Z. AFTER THE STORM DEPARTS...WENT AT OR BELOW THE COOLEST END OF GUIDANCE. MODELS HAVE NOT BEEN ACCURATELY DEPICTING THE AMOUNT OF COLD AIR BEHIND THESE SYSTEMS AND THAT DOES NOT EVEN TAKE INTO ACCOUNT THE SNOW AND ICE THAT WILL LIKELY BE ON THE GROUND. .LONG TERM...SUN NIGHT THROUGH FRIDAY A CLIPPER SYSTEM WILL DROP SOUTHEAST ACROSS THE REGION TUESDAY AND TUESDAY NIGHT AND MAY BRUSH NORTHEAST SECTIONS WITH SOME LIGHT SNOW. SOME FLURRIES SHOULD LINGER INTO WEDNESDAY NORTHEAST WITH COLD AIR AND CYCLONIC FLOW. THE GFS IS MORE AGGRESSIVE WITH THE ECMWF WITH THE PUSH OF COLD AIR BEHIND THE SYSTEM TUESDAY NIGHT INTO WEDNESDAY. WILL STAY CLOSE TO HPC GUIDANCE FOR TEMPS FOR NOW. THE GFS BRINGS ANOTHER S/W TROUGH ACROSS IOWA LATE THURSDAY WHILE THE ECMWF DIGS THE SYSTEM FARTHER SOUTH. CONFIDENCE NOT HIGH ENOUGH TO INTRODUCE ANY ADDITIONAL POPS AT THIS TIME. && .AVIATION...1/06Z NO MAJOR CHANGES TO THE ONGOING TAFS IN REGARDS TO THE FROZEN PRECIP AND IFR CONDITIONS. HOWEVER...NORTHERN TAF SITES ARE MOST PROBLEMATIC WITH FROZEN PRECIP...WHILE THE CHANGEOVER TO RAIN ACROSS THE SOUTH SEEMS TO BE EARLIER IN THE AFTERNOON WITH WAA. FOR MCW AND FOD HAVE FZRA FOR A LONGER TIME FRAME AS MODEL SOUNDINGS HAVE FZRA FOR A GOOD 6-8 HOURS. MCW AND FOD WILL LIKELY GET SOME MIX OF SN AND PL AT THE ONSET...BUT HAVE CHANGOVER TO FZRA BY 17-18Z. ALL TAFS THROUGH AT LEAST 18Z...HAVE IFR CONDITIONS BEGINNING AT 14-15Z WITH ONLY MCW DROPPING TO LIFR CONDITIONS B/T 19-23Z FOR VIS. DSM LOOKS TO CHANGE OVER TO RAIN DURING THE AFTERNOON...WITH GFS THE WARMER AND QUICKER MODEL IN THE CHANGEOVER THAN NAM. CIGS SHOULD CONTINUE TO REMAIN IFR THROUGH MUCH OF THE TAF PERIOD PAST 15Z SAT. && .DMX WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING ALONG AND NORTH OF HIGHWAY 30 PLUS TAMA COUNTY 12Z SAT-12Z SUN. ICE STORM WARNING 12Z-21Z SAT REMAINDER OF FORECAST AREA. && $$ MDR/BSS/RPK...SHORT/LONG TERM KLP...06Z AVIATION ia AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1224 AM EST SAT DEC 1 2007 UPDATED FOR 06Z AVIATION DISCUSSION .UPDATE (ISSUED AT 1013 PM EST)... LES IS DIMINISHING OVER NW UPPER MI AS EXPECTED. OBS INDICATE PRONOUNCED CONVERGENCE OVER THE WRN PART OF THE LAKE WITH SSW WINDS AT SAXON HARBOR/ONTONAGON AND NW WINDS AT ISLE ROYALE AND THE KEWEENAW. ONTONAGON BRIEFLY SHIFTED NW AT 02Z BUT IS BACK TO SW NOW. EVEN SO...THERE AREN`T ANY DOMINANT BANDS SHOWING UP ON SATELLITE IMAGERY AS LOWERING INVERSION/DRY AIR ARE APPARENTLY NEGATIVELY IMPACTING LES. TO THE E...DOMINANT BAND...AIDED BY ENHANCED LAND BREEZE CONVERGENCE...HAS HAMMERED ERN PARTS OF ALGER COUNTY LATE AFTN/EARLY EVENING. SNOWFALL RATES WERE PROBABLY 2-3IN/HR. BAND HAS BEEN SLOWLY SHIFTING SW (NOW OVER MUNISING) WITH SLIGHT VEERING OF LOW-LEVEL WINDS THIS EVENING...BUT IT IS ALSO BEGINNING TO WEAKEN A BIT NOW. WIDE SEPARATION IS ALSO NOTED BTWN THE LES BANDS. GOING FCST APPEARS TO HAVE A GOOD HANDLE ON THE SITUATION OVERNIGHT...SO NO SIGNIFICANT CHANGES WILL BE MADE TO FCST. DOMINANT BAND IMPACTING ALGER COUNTY MAY SLIP A BIT FARTHER W INTO THE WRN PART OF THE COUNTY...BUT IT SHOULD CONTINUE TO WEAKEN GIVEN LOWERING INVERSION. THEN AS SFC HIGH PRES MOVES ACROSS THE AREA...ALLOWING LAND BREEZES TO BECOME EVEN MORE INFLUENTIAL...LES SHOULD BEGIN TO RETREAT CLOSER TO THE SHORELINES AND THEN ALMOST COMPLETELY OFFSHORE BY DAYBREAK. THIS INCLUDES NW UPPER MI AS WELL. EXPECT ADDITIONAL ACCUMULATIONS OVER THE ERN HEADLINE AREAS TO GENERALLY RANGE FROM 1 TO 4 INCHES...PROVIDED PRESENT WEAKENING TREND CONTINUES AS IT SHOULD. TO THE NW...ACCUMULATIONS SHOULD RANGE FROM 1 TO 2 INCHES. ELSEWHERE...WILL DROP MIN TEMPS OVER THE INTERIOR W AS OBS SHOW TEMPS FALLING TO NEAR OR BLO FCST MINS ALREADY (KLNL ALREADY FELL TO -8F AND KIMT -2F). STRATOCU FIELD HAS SPREAD WELL INLAND FROM LAKE SUPERIOR RECENTLY AND CAUSED TEMPS TO SPIKE BACK UP...BUT THERE MAY STILL BE A WINDOW FOR TEMPS TO PLUMMET AGAIN AFTER STRATOCU DEPARTS AND HIGH CLOUDS ARRIVE. MAY SEE -10F OR SO IN THE TYPICAL COLD SPOTS. && .PREV DISCUSSION (ISSUED 440 PM EST)... SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH UPR GRT LKS DOMINATED BY ARCTIC BRANCH TROFFING CENTERED OVER NW ONTARIO. VERY COLD AIRMASS UNDER THIS TROF...WITH 12Z H5/H85 TEMPS OF -40C/-31C AT YPL. PASSAGE OF THIS AIRMASS OVER THE RELATIVELY WARM WATERS OF LK SUP (ARND 4C) IN WNW FLOW BTWN HI PRES NR OMA AND LO PRES MOVING THRU SE ONTARIO HAS RESULTED IN NMRS WIND PARALLEL LES BANDS THAT ARE IMPACTING THOSE PORTIONS OF THE FA FVRD BY WNW LLVL FLOW. ALTHOUGH UPSTREAM AIRMASS IS DRY IN AN ABSOLUTE SENSE (12Z PWAT ONLY 0.06 INCH AT INL WITH SFC DWPTS ARND -10F)...AN INSPECTION OF THE INL AND YPL RAOBS AS WELL AS THE 13Z TAMDAR SDNG FM HIB INDICATES THE LLVLS ARE RELATIVELY MOIST. IN FACT...BACK EDGE OF LK SC IS NOT SEPARATING FM THE MN NORTH SHORE...SUGING DRYING IS NOT OVERWHELMING THE LES INTENSITY YET. SPOTTER REPORTS FM THE E ARND GRAND MARAIS INDICATE UP TO 3 INCHES OF SN FELL IN JUST 3 HOURS OR SO THERE THIS MRNG WHEN LES BAND CAME ASHORE. OVER THE SCNTRL...SKIES ARE GENERALLY CLR TO PCLDY WITH TEMPS WELL BLO NORMAL FOR THE SEASON (17Z WIND CHILL AS LO AS -18F AT IWD). AIRMASS FARTHER TO THE W CLOSER TO SFC HI PRES RDG IN THE PLAINS IS EVEN DRIER/MORE STABLE PER 12Z BIS/ABR SDNGS. A POTENT SHRTWV IN THE POLAR BRANCH FLOW IS DIGGING THRU CA (12HR H3 HGT FALLS CLOSE TO 200M) WITH ANOTHER SUBTROPICAL JET DISTURBANCE MOVING NEWD TOWARD THE DESERT SW. HI CLDS AHEAD OF THESE FEATURES ARE ALREADY STREAMING INTO THE CNTRL PLAINS...WITH A DECENT TAP OF TROPICAL MSTR FLOWING N AS SHOWN ON WV IMAGERY. SHORT TERM (TNGT/SAT)... MAIN FCST CONCERNS DURING THIS TIME ARE LES TRENDS/AMTS THRU TNGT. FOCUS ON SAT SHIFTS TO GATHERING STORM IN THE PLAINS ASSOCIATED WITH POLAR/SUBTROPICAL BRANCH DISTURBANCES UPSTREAM AND TIMING OF ANY ACCOMPANYING PCPN INTO THE FA. FOR TNGT...MODELS FCSTG 00Z-12Z H5 HGT RISES UP TO 100M OVER THE UPR GRT LKS BTWN DEPARTING ARCTIC BRANCH TROF AND DEEPENING TROF IN THE W ASSOCIATED WITH DISTURBANCES MENTIONED IN THE SYNOPSIS. ARRIVAL OF SFC HI PRES RDG UNDER THESE HGT RISES AS WELL AS DRIER/ MORE STABLE AIRMASS NOW OVER THE NCNTRL PLAINS SHOULD RESULT IN A GRADUAL DIMINISHING TREND TO THE LES/WINDS/BLSN TNGT. HOWEVER... LES WL LINGER THRU MOST OF THE NGT E OF P53 IN MORE PERSISTENT WNW FLOW. SINCE GFS/NAM/LOCAL HI RES MODEL RUNS SHOW FAIRLY SHARP LLVL CNVGC PERSISTING OVER THE E BTWN LARGER SCALE WNW FLOW AND DVLPG WSW LAND BREEZE FLOW OFF LAND TO THE N OF HI CENTER TRACKING THRU WI...WL CONTINUE GOING WINTER STORM WRNG FOR THE E. EARLIER RUNS HAD SHOWN PERSISTENT LAND BREEZE CNVGC WITH LARGER SCALE WNW FLOW IMPACTING ONTONAGON COUNTY THRU THIS EVNG...BUT LATEST OB FM ONTONAGON SHOWS THE WIND THERE HAS ALREADY SHIFTED TO THE SSW. SO ALLOWED GOING WRNG FOR THAT AREA TO EXPIRE AT 00Z AS SCHEDULED. SINCE THE EARLIER GUIDANCE SUGGESTED THE LAND BREEZE CNVGC AXIS WOULD SHIFT STEADILY N THRU TNGT AFTER STALLING OVER ONTONAGON COUNTY...LIMITING THE RESIDENCE TIME OVER THE KEWEENAW... ALLOWED GOING WRNG TO EXPIRE AT 00Z FOR KEWEENAW/NRN HOUGHTON AS WELL. BUT IF THE CNVGC AXIS PERSISTS FARTHER N...THE WRNG FOR THESE ZNS MAY HAVE TO BE EXTENDED. OTRW...WL TEND TOWARD THE LO END OF MOS GUIDANCE FOR TEMPS OVER THE INTERIOR AWAY FM LK MODERATION PER DRY AIRMASS UPSTREAM EVEN THOUGH SOME HI CLD MAY DRIFT IN LATE. MANY INTERIOR PLACES WL SEE SOME SUB ZERO MINS. ON SAT...LINGERING LES OVER THE KEWEENAW/ERN ZNS WL END SAT MRNG AS THE LARGER SCALE FLOW BACKS TO S BTWN DEPARTING HI PRES TO THE E AND DVLPG LO PRES IN THE PLAINS. THERE WL ALREADY BE QUITE A BIT OF MID/ HI CLD STREAMING INTO THE FA AT 12Z...AND THESE CLDS WL THEN LOWER AND THICKEN DURING THE DAY AS UPR DVGC IN RRQ OF RETREATING H3 JET MAX AND DVLPG DEEP LYR ISENTROPIC LIFT AS SHOWN ON THE GFS FCST 280K-310K SFCS. NAM IS SLOWER THAN THE GFS WITH THE DVLPMNT OF THESE FEATURES...BUT NCEP PREFERS THE FASTER GFS. WENT LIKELY POPS NEAR THE WI BORDER AFT 18Z CLOSER TO THE DEEPER MSTR/SHARPER DYNAMICS AND/OR WHERE SE UPSLOPE FLOW OFF LK MI MIGHT ENHANCE MOISTENING. BUT TENDED TO GO SLOWER INTRODUCING THE HIER POPS FARTHER NE AS GFS SHOWS SHARPER H8-6 FGEN/UPR DVGC TENDING TO REMAIN TO THE S THRU SAT AFTN. UP TO 2-3 INCHES OF SN MAY ACCUMULATE ALONG THE WI BORDER BY 00Z SUN. LONG TERM (SAT NIGHT THRU FRI)... THE MAIN FORECAST DILEMMA CONTINUES TO BE THE POTENTIAL FOR HEAVY SNOW AND POSSIBLY MIXED PRECIPITATION SATURDAY NIGHT AND SUNDAY. 06Z GFS HAD THE SURFACE LOW OVER S-SW WISCONSIN AT 12Z SUNDAY. THE 12Z NAM WAS SLIGHTLY SLOWER...WITH THE LOW STILL OVER S-CENTRAL IOWA. IN FACT...IT IS ABOUT 4 TO 6 HOURS SLOWER THAN THE GFS. THIS COULD MAKE A SIGNIFICANT DIFFERENCE IN TIMING OF HEAVY SNOW OR MIXED PRECIPITATION OVER THE REGION. TAKING THIS TIMING DIFFERENCE INTO ACCOUNT...THE 540 LINE IS LOCATED IN SIMILAR LOCATIONS...ENCOMPASSING ALL OF THE U.P. EXCLUDING KEWEENAW COUNTY AND POSSIBLY THE NORTHERN TIP OF LUCE COUNTY. WILL NEED TO KEEP THIS IN MIND AS WE FIGURE OUT THE TYPE OF PRECIPITATION POSSIBLE SATURDAY NIGHT AND SUNDAY. EITHER WAY...AFTER 03Z MONDAY...SNOW WILL DOMINATE UPPER MICHIGAN AS WINDS BECOMING NORTHWESTERLY WITH THE SURFACE LOW SLIDES EASTWARD INTO LAKE HURON AND EXTREME SOUTHEASTERN ONTARIO. WHEN COMPARING THE TRACK OF THIS SURFACE LOW WITH THE CAN/ECMWF/UKMET/GFS/NAM...THE NAM WAS INDEED MUCH SLOWER. AS A RESULT OF THIS AND THE FACT THAT IT WAS NOTED IN THE PREVIOUS DISCUSSION THAT IT WAS ONE OF THE FARTHER SE MODELS....WITH LIMITED RUN TO RUN CONSISTENCY...IT WAS DISCREDITED AND NOT USED IN THIS FORECAST PACKAGE BEYOND 00Z SUNDAY. AT 00Z MONDAY...THERE WERE GENERALLY 3 TRAINS OF THOUGHT...THE AFOREMENTIONED SLOW NAM...THE MORE NORTHERN AND CONSISTENTLY DEEPER UKMET/CANADIAN...AND THE QUICKER GFS/ECMWF. WILL HEDGE THE FORECAST TO THE GFS/ECMWF WITH SOME THOUGHT GIVEN TO THE BLEND OF THE CANADIAN/UKMET. SO...FORECAST WISE...WILL INCREASE TEMPERATURES SLIGHTLY FOR SUNDAY MORNING ON OUR STRENGTHENING SOUTHEASTERLY AND PLENTY OF CLOUD COVER. ELEVATED WARM LAYER ACROSS THE SOUTHERN HALF OF THE CWA MAY POSE A PROBLEM FOR MIXED PRECIPITATION...AS POCKET 0 TO -2C BETWEEN 700 AND 800MB SHOWS UP FROM 09Z-17Z SUNDAY AFTERNOON AT IMT WITH SFC TEMPS NEAR OR JUST ABOVE FREEZING. SO HAVE UTILIZED THE 750MB GFS TEMPS HEAVILY WHEN FIGURING OUT WEATHER FOR...SINCE THE SNOW GROWTH REGION IS BETWEEN 500 AND 600MB. EXPECT TEMPERATURES TO MAX OUT RIGHT AROUND 18Z...SO JUST SLIGHTLY BEFORE CLIMATOLOGICAL NORM. STILL...BY THIS TIME...MUCH OF THE ACCUMULATED SNOW WILL HAVE FALLEN. AS A RESULT...WARNINGS SEEM LIKELY. LOOKING AT MONDAY NIGHT/00Z TUESDAY THE 06Z GFS IS SLOWER THAN THE 00Z ECMWF TO PUSH THE 500MB CLOSED LOW EASTWARD TO THE NEW ENGLAND STATES...COMING MORE IN LINE WITH EACH OTHER BY 00Z WEDNESDAY FOR AT LEAST THE LOCATION OF THE 500MB LOW. HOWEVER...CLOSER TO HOME THE NEXT EMBEDDED TROUGH IN THIS LARGE SCALE FEATURE CAN BE EXPECTED TO SLIDE SOUTHWARD FROM NORTHERN ONTARIO TO NORTHERN LAKE SUPERIOR BY 00Z WEDNESDAY. THE 06Z GFS IS STRONGER/DEEPER WITH THIS NEXT SYSTEM. THE 06Z GFS...WITH ITS STRONGER TROUGH...KEEPS THE GENERAL TROUGHINESS OVER THE REGION THROUGH THURSDAY NIGHT INTO EARLY NEXT FRIDAY. ON THE OTHER HAND...WITH AN OVERALL WEAKER RENDITION...THE 00Z ECMWF WOULD ALLOW FOR SMALL SCALE RIDGING FOR A MAJORITY OF THE TIME FROM TUESDAY AFTERNOON ON. SO...THERE ARE SIGNIFICANT DIFFERENCES IN MODEL GUIDANCE OVER UPPER MICHIGAN. HPC GUIDANCE WAS HEAVILY UTILIZED...FOR DAYS 4/TUESDAY THROUGH 7/FRIDAY. THIS DID NOT INCLUDE THE 00Z CANADIAN...BUT WAS INSTEAD THE 00Z ECMWF EARLY IN THE PERIOD BEFORE A 50/50 BLEND OF THE 00Z ECMWF/NCEP ENSEMBLE MEAN FROM WEDNESDAY MORNING ONWARD...WITH PLENTY OF UNCERTAINTY IN THE LATER PART OF THE FORECAST PERIOD. WHAT IS MORE CERTAIN IS BELOW TO WELL BELOW AVG TEMPS WILL EXTEND FROM OUR REGION THROUGH THE SOUTHEASTERN UNITED STATES MIDWEEK. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KSAW...VFR CONDITIONS WILL PREVAIL THRU MID AFTN. AFTER THAT... APPROACHING WINTER STORM WILL RESULT IN A RAPID LOWERING OF CIGS/VIS TO MVFR/IFR AS SNOW OVERSPREADS THE AREA. CONDITIONS WILL FURTHER DETERIORATE TO VLIFR IN MDT/HVY SN THIS EVENING. AT KCMX...LINGERING -SHSN SHOULD MAINTAIN MVFR VIS/CIGS FOR MUCH OF THIS MORNING. MIGHT SEE SOME BRIEF IFR VIS FOR THE NEXT COUPLE OF HRS. CONDITIONS WILL GO TO VFR AROUND SUNRISE AS LAKE EFFECT CLOUDS/FLURRIES EXIT. THEN...JUST LIKE KSAW...THERE WILL BE A RAPID LOWERING OF CIGS/VIS TO MVFR/IFR LATE IN THE AFTN AS SNOW OVERSPREADS THE AREA. VLIFR CONDITIONS IN MDT/HVY SN AND BLSN EXPECTED TO DOMINATE THIS EVENING. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER EASTERN ONTARIO TO MOVE TO MAINE TONIGHT AS HIGH PRESSURE OVER THE CENTRAL PLAINS MOVES TO THE OHIO VALLEY AND GREAT LAKES. LINGERING WNW GALES THIS EVNG WILL DIMINISH BY MIDNGT AS THE WEAKER PRES GRADIENT ASSOCIATED WITH THE HIGH PUSHES EWD. THE HIGH WILL REACH WESTERN QUEBEC BY SATURDAY EVENING AS A LOW PRESSURE OF 29.2 INCHES OVER THE CENTRAL PLAINS SATURDAY EVENING REACHES LAKE MICHIGAN SUNDAY AFTERNOON. THERE WILL LIKELY BE ANOTHER ESE GALE SAT NGT INTO SUN AS THIS LOW GRINDS INTO HI PRES TO THE NE AND SHARPENS THE PRES GRADIENT OVER THE UPR LKS. THE LOW WILL THEN REACH THE EASTERN GREAT LAKES BY MONDAY MORNING AS ANOTHER HIGH PRESSURE RIDGE MOVES INTO THE PLAINS. ANOTHER N GALE EVENT IS LIKELY SUN NIGHT INTO MONDAY IN THE TIGHT PRES GRADIENT BETWEEN THESE FEATURES. THE RIDGE WILL THEN MOVE TO THE EASTERN GREAT LAKES WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM MAKES ITS WAY FROM ALBERTA TO SOUTHERN LAKE MICHIGAN. ATTM...EXPECT N WINDS TO 30 KTS AS THE PRES GRADIENT TIGHTENS OVER THE UPR LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING FROM 7 PM SATURDAY TO 1 PM EST SUN MIZ001-003>007-014-085. WINTER STORM WARNING FROM 1 PM EST /12 PM CST/ SAT TO 1 PM EST /12 PM CST/ SUN MIZ002-009>013-084. LAKE EFFECT SNOW ADVY UNTIL 3 AM EST SAT MIZ085. WINTER STORM WARNING UNTIL 5 AM EST SAT MIZ006-007. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 300 AM MST SAT DEC 1 2007 .DISCUSSION... DRY AIR ALREADY PUNCHING INTO SOUTHWEST ARIZONA...SO TAP OF SUBTROPICAL MOISTURE SHOULD BE SHIFTING EASTWARD DURING THE DAY TODAY. RUC INDICATES A FASTER TRANSITION TO COLDER TEMPS ALOFT THIS MORNING...CLOSER TO THE GFS...WHILE THE NAM HOLDS OFF WITH THE COLDER AIR UNTIL AFTER SUNSET TONIGHT. AS A NOTE...EARLIER RAIN HAD TRANSITIONED TO SNOW AT KGCN AS OF 09Z. ROUGHLY NORTHWEST THIRD TO HALF OF THE FORECAST AREA...NORTHWEST PLATEAU...WESTERN AND NORTHERN MOUNTAINS MAY EXPERIENCE ISOLATED THUNDER DURING THE DAY TODAY AS A MORE UNSTABLE PROFILE COULD RESULT. A 12 TO 16 MB SURFACE GRADIENT IS FORECAST TO DEVELOP ACROSS EASTERN NEW MEXICO THIS MORNING. WITH 50 KT WINDS SHOWING UP ON KTCC AND WSMR WIND PROFILERS TONIGHT...ENOUGH EVIDENCE FOR TODAY/S WIND HIGHLIGHTS TO REMAIN IN PLACE. CONCERNED LINCOLN COUNTY MAY TO BE UPGRADED...AS THEY MAY EXPERIENCE THE BETTER CLEARING TODAY. AREAS OUR WEST MAY ALSO BLOW CLOSE TO WIND ADVISORY TODAY. ENOUGH LINGERING MOISTURE MAY EXIST TO TURN ANY REMAINING RAIN TO SNOW OVER MUCH OF THE W...AS WELL AS THE CENTRAL AND SOUTH CENTRAL MOUNTAINS...CENTRAL HIGH PLAINS AND NE HIGHLANDS TONIGHT ONCE THE COLDER AIR ARRIVES. AN EXTENSION OR EXPANSION OF SOME SORT OF WINTER WEATHER HIGHLIGHTS MAY NEED TO BE ISSUED FOR SOME OF THESE AREAS ON LATER SHIFTS. THE WINDS AND PRECIPITATION WILL DIMINISH SUNDAY WITH ANY LINGERING PRECIPITATION CONFINED TO THE CENTRAL AND WEST. THE REST OF THE WEEK IS NOW LOOKING AS IF IT WILL BE DRY...WITH NO STORMS ON THE HORIZON UNTIL NEXT WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 48 30 46 20 / 80 40 10 0 GALLUP.......................... 47 25 45 10 / 70 50 10 0 GRANTS.......................... 50 27 47 13 / 60 40 10 0 GLENWOOD........................ 60 32 61 21 / 70 20 10 0 CHAMA........................... 36 23 38 10 / 90 60 20 0 LOS ALAMOS...................... 45 29 46 20 / 80 50 10 0 RED RIVER....................... 35 18 37 4 / 80 50 10 0 TAOS............................ 42 24 44 8 / 80 40 10 0 SANTA FE........................ 49 28 46 19 / 70 40 10 0 SANTA FE AIRPORT................ 51 30 48 23 / 70 40 10 0 ESPANOLA........................ 50 32 52 17 / 70 40 10 0 ALBUQUERQUE HEIGHTS............. 53 34 51 29 / 50 30 10 0 ALBUQUERQUE VALLEY.............. 54 33 52 22 / 50 30 10 0 ALBUQUERQUE FOOTHILLS........... 52 31 47 25 / 50 30 10 0 ALBUQUERQUE WEST MESA........... 53 33 52 26 / 50 30 10 0 SOCORRO......................... 59 34 57 24 / 40 10 10 0 SANDIA PARK/CEDAR CREST......... 47 27 45 23 / 50 30 10 0 MORIARTY/ESTANCIA............... 55 29 51 21 / 40 30 10 0 CARRIZOZO....................... 58 37 57 24 / 40 10 10 0 RUIDOSO......................... 57 32 50 25 / 60 10 10 0 RATON........................... 54 27 49 14 / 50 20 10 0 LAS VEGAS....................... 51 30 48 23 / 50 30 10 0 ROY............................. 57 32 53 25 / 40 20 5 0 CLAYTON......................... 63 35 54 28 / 40 10 5 0 SANTA ROSA...................... 63 34 59 26 / 40 10 5 0 TUCUMCARI....................... 65 40 60 29 / 40 10 5 0 FORT SUMNER..................... 64 39 59 27 / 40 10 5 0 CLOVIS.......................... 66 41 60 30 / 40 10 0 0 PORTALES........................ 66 40 63 29 / 40 10 0 0 ROSWELL......................... 64 44 64 32 / 40 10 5 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES ABOVE 7500 FEET...NMZ002-004. HIGH WIND WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ005>007-011>013. WIND ADVISORY UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ010-016>021-026. && $$ nm AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 320 AM CST SAT DEC 1 2007 .SHORT TERM...TODAY THROUGH MONDAY NIGHT THE MAIN FORECAST CONCERN CONTINUES TO BE THE HIGH IMPACT WINTER STORM THAT WILL BE AFFECTING THE AREA TODAY AND TONIGHT. DATA ANALYSIS AT 07Z SHOWS AN AREA OF HIGH PRESSURE STRETCHING FROM THE OHIO VALLEY BACK INTO WISCONSIN...WHILE AN AREA OF LOW PRESSURE WAS FORMING IN THE LEE OF THE ROCKIES. PRESSURE GRADIENT ALREADY TIGHTENING UP BETWEEN THESE TWO SYSTEMS ACROSS THE PLAINS. PROFILER DATA SHOWING 40 KNOT 850MB WINDS FROM OKLAHOMA...INTO SOUTHERN NEBRASKA. LOOKING AT THE 00Z PRECIPITABLE WATER PLOT FROM NCEP IS SHOWING QUITE IMPRESSIVE VALUES ACROSS THE SOUTHERN PLAINS WITH OVER 200 PERCENT OF NORMAL AT KOKC. MEANWHILE INFRARED SATELLITE IMAGERY SHOWING CLOUDS HAVE OVERSPREAD THE FORECAST AREA. 00Z MODELS OFFER SIMILAR SOLUTIONS AND REMAIN CONSISTENT FROM PREVIOUS RUNS. ONLY DIFFERENCES IS SLIGHT TIMING DIFFERENCES IN THE ONSET OF PRECIPITATION TODAY. ALSO SOME DIFFERENCES WITH THE AMOUNT OF WARM AIR THAT GETS PULLED NORTHWARD...WITH THE GFS BEING THE WARMER SOLUTION. HAVE GENERALLY USED A BLEND FOR THE WARM AIR ALOFT BETWEEN THE NAM AND GFS. IN THE SHORT TERM...BOTH THE 00Z ARXMESOWRF AND RUC SHOWING PRECIPITATION SPREADING INTO THE FORECAST AREA BETWEEN 15Z AND 18Z THIS MORNING. MODEL SOUNDINGS INDICATE ALL SNOW AT THE ONSET. AS WE HEAD THROUGH THE DAY...STRONG WARM ADVECTION/ISENTROPIC LIFT SPREAD ACROSS THE AREA. COPIOUS AMOUNTS OF MOISTURE WILL BE ADVECTED NORTHWARD ON ANOMALOUS 60 TO 70 KNOT LOW LEVEL JET. GOOD DIVERGENCE ALOFT IN RIGHT ENTRANCE REGION OF THE 150-180KT 300MB JET NORTH OF THE GREAT LAKES WILL AID IN LIFT ACROSS THE FORECAST AREA. WITH THE MOISTURE AND LIFT IN PLACE...THE QUESTION BECOMES PRECIPITATION TYPE AS WARM AIR GETS WRAPPED NORTHWARD. MODELS HAVE BEEN VERY CONSISTENT WITH SURGE OF WARMER AIR ALOFT BETWEEN 800MB-650MB THIS AFTERNOON INTO TONIGHT. TOP DOWN APPROACH FROM AREA MODEL SOUNDINGS INDICATE SNOW TO CHANGE TO SLEET AND FREEZING RAIN ACROSS THE SOUTHERN ZONES EARLY THIS AFTERNOON THEN ACROSS THE CENTRAL SECTIONS OF THE FORECAST AREA BY MID TO LATE AFTERNOON AND FINALLY INTO PORTIONS OF THE NORTHERN SECTIONS BY TONIGHT. WITH MODEL QPF OUTPUT OF OVER AN INCH...EXPECT SIGNIFICANT ACCUMULATIONS OF SNOW/SLEET AND FREEZING RAIN. THE HEAVIEST SNOW WILL BE FOUND ACROSS NORTHERN TAYLOR COUNTY...WITH LESSER AMOUNTS DUE TO THE MIXED PRECIPITATION TYPES FARTHER SOUTH. HIGHEST ICE AMOUNTS WILL BE ACROSS THE SOUTHERN ONE HALF OF THE FORECAST AREA WHERE MORE THAN ONE QUARTER OF AN INCH OF ICE IS EXPECTED. IN ADDITION...A TIGHT PRESSURE GRADIENT WILL RESULT IN RATHER STRONG WINDS THIS AFTERNOON INTO THIS EVENING. BUFKIT SHOWING THE POTENTIAL FOR 35 TO 40 MPH GUSTS AROUND THE AREA...WHICH COULD RESULT IN BRANCHES BREAKING AND POWER OUTAGES DUE TO ICING. PRECIPITATION WILL TAPER OFF LATE TONIGHT TO MORE DRIZZLE/FREEZING DRIZZLE AS HIGH ICE PRODUCING CLOUDS EXIT THE AREA. ALL IN ALL THE CURRENT GRIDDED DATA BASE HAS THIS WELL IN HAND AND MADE NO CHANGES TO THE POP/WEATHER GRIDS THROUGH TONIGHT. WRAP AROUND MOISTURE ON SUNDAY TO RESULT IN CHANCE POPS...ESPECIALLY DURING THE MORNING HOURS WITH THE CHANCES WANING IN THE AFTERNOON. TIGHT PRESSURE GRADIENT WILL KEEP WINDS QUITE BLUSTERY IN ITS WAKE. HIGH PRESSURE THEN BUILDS IN LATE SUNDAY NIGHT INTO MONDAY FOR QUIET BUT COLD WEATHER. INCREASING CLOUDS EXPECTED MONDAY NIGHT AS ANOTHER WAVE DROPS SOUTHWARD TOWARD THE AREA. TEMPERATURES RATHER TRICKY...AS WE WILL BE WARMING THROUGHOUT THE DAY TODAY AND HOLD STEADY OR SLOWLY RISE THROUGH THE FIRST HALF OF TONIGHT WITH THE STRONG WARM ADVECTION. COOLER AIR THEN ARRIVES ON SUNDAY...WITH HIGHS MOST LIKELY SEEN DURING THE MORNING HOURS. HAVE USED A NON DIURNAL TEMPERATURE TREND FROM TODAY THROUGH SUNDAY NIGHT TO TAKE THIS INTO ACCOUNT. .LONG TERM...TUESDAY THROUGH FRIDAY 00Z GFS AND ECMWF SHOW NORTHWEST FLOW ACROSS THE AREA THROUGH THURSDAY BEFORE FLOW BECOMES MORE ZONAL ON FRIDAY. SHORTWAVE TO DROP ACROSS THE AREA IN THE TUESDAY/WEDNESDAY TIME FRAME THAT COULD BRING A SWATH OF LIGHT SNOW TO THE AREA. THIS COVERED IN THE GRIDS WILL CHANCE/SLIGHT CHANCE POPS. OTHERWISE...TEMPERATURES LOOK TO REMAIN BELOW NORMAL THROUGH THE PERIOD. NO CHANGES MADE TO THE GRIDDED DATABASE IN THIS TIME FRAME. && .AVIATION...TODAY AND TONIGHT A VERY POTENT/HIGH IMPACT WINTER STORM IS EXPECTED TO AFFECT THE AREA TODAY THROUGH TONIGHT. LOW PRESSURE WILL CONTINUE TO ORGANIZE AND DEEPEN OVER THE COLORADO ROCKIES THIS MORNING. A VERY STRONG SOUTHERLY AIRFLOW BETWEEN 2-5KFT AHEAD OF THE LOW WILL ADVECT ABUNDANT MOISTURE FROM THE PLAINS INTO THE UPPER MIDWEST. THIS WILL CAUSE SNOW TO RAPIDLY OVERSPREAD THE AREA DURING THE MID-LATE MORNING HOURS AND WILL CAUSE RAPID REDUCTIONS IN CLOUD CEILINGS HEIGHTS AND VISIBILITIES. FORECAST CONFIDENCE REMAINS HIGH THAT THE HEAVIEST PRECIPITATION SHOULD OCCUR BETWEEN ABOUT 18Z SATURDAY UNTIL AROUND 06Z SATURDAY NIGHT AS THE AREA OF LOW PRESSURE MOVES ACROSS THE CENTRAL PLAINS INTO THE UPPER MIDWEST. AGAIN...THE PRECIPITATION AT BOTH KLSE AND KRST TAF SITES SHOULD BEGIN AS SNOW THIS MORNING... BUT THEN CHANGE OVER TO FREEZING RAIN AND SLEET LATER THIS AFTERNOON INTO THIS EVENING AS WARMER AIR ALOFT IS PULLED ACROSS THE AREA. PLEASE SEE LATEST TAFS...HAZARDOUS WEATHER OUTLOOK AND WINTER WEATHER STATEMENTS FOR FURTHER DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER STORM WARNING FROM 6 AM TODAY TO 6 AM CST SUNDAY FOR WIZ017-WIZ029-WIZ032-WIZ033-WIZ034-WIZ041-WIZ042-WIZ043- WIZ044-WIZ053-WIZ054-WIZ055-WIZ061. MN...WINTER STORM WARNING FROM 6 AM TODAY TO 6 AM CST SUNDAY FOR MNZ079-MNZ086-MNZ087-MNZ088-MNZ094-MNZ095-MNZ096. IA...WINTER STORM WARNING FROM 6 AM TODAY TO 6 AM CST SUNDAY FOR IAZ008-IAZ009-IAZ010-IAZ011-IAZ018-IAZ019-IAZ029-IAZ030. && $$ SHORT/LONG TERM...RABERDING AVIATION..........DAS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 920 AM MST SAT DEC 01 2007 .UPDATE...MADE SOME CHANGES TO THE HIGHLIGHTS BASED ON RADAR TRENDS. DECENT SHOWER BAND ROTATING THROUGH OUR MOUNTAINS NOW APPEARS STRONGER THAN EARLIER ANTICIPATED...SO I WILL NEED TO RAISE POPS FOR THE PLAINS IN AN UPCOMING ZONE UPDATE. SCOURING OF LOW LEVEL AIR IS ALSO NOT HAPPENING YET...AND I AM SKEPTICAL OF IT COMING RAPIDLY TO THE PLATTE RIVER VALLEY GIVEN THE DEPTH OF THE COLD AIR IN PLACE AND LIKELY DENVER CYCLONE/SHEAR ZONE DEVELOPMENT. THIS MEANS A LITTLE FREEZING RAIN IS LIKELY ON THE PLAINS...AND IN FACT ALREADY HAD A LITTLE SHOWER BAND COME THROUGH WHICH WAS ENOUGH TO CLOSE INTERSTATE 25 NORTH OF WELLINGTON. SO...ISSUING A FREEZING RAIN ADVISORY FOR THE AREA OF HIGHEST THREAT TIMED TO THE MAIN SHOWER BAND MOVING THROUGH. PROBABLY SOME FREEZING RAIN FURTHER SOUTH...BUT THE SOUTH END OF THE BAND APPEARS WEAKENING...LOWER THREAT ACROSS DENVER. EARLIER ISSUED A WINTER STORM WARNING FOR FREEZING RAIN/SNOW COMBO IN ZONE 32...KREMMLING HAD HALF AN INCH OF FREEZING RAIN DURING THE EARLY MORNING HOURS...REPORTEDLY SNOW IN THE GRANBY/FRASER AREAS. && .PREVIOUS DISCUSSION FROM 400 AM...DEEP UPR LVL VORTEX OVR SRN CA AT THE BOTTOM OF A HIGH AMPLITUDE TROUGH NOW CROSSING THE GREAT BASIN. NEWRD PROGRESS OF THE UPR LOW APPEARS TO HAVE PICKED UP SPEED. BACK EDGE OF CLOUD SHIELD IN THE VICINITY OF THE MAIN CORT MAXIMA TIMED TO REACH NWRN AND CNTRL COLORADO BY AROUND MIDDAY. THAT MATCHES UP PRETTY CLOSELY WITH TIMING OF THE RUC...BUT MUCH QUICKER THAN THAT OFFERED BY THE NAM AND GFS. HOWEVER CAN`T IGNORE THE JET LEVEL ENERGY AND CAA STILL COMING DOWN THE BACK SIDE OF THE TROUGH. SUSPECT WE`LL SEE A RESURGENCE OF CLOUDS AND SNOWFALL LATER THIS MORNING ALONG AND WEST OF THE CONTINENTAL DIVIDE WITH PASSAGE OF THE 700-500 MB TROUGH AXIS. QG OMEGA FIELDS SHOWS AN AREA OF MODERATE UPWARD QG VERTICAL MOTION MOVING OVER THE AREA BY THIS AFTERNOON. FURTHERMORE A SHIFT TO W-NWLY FLOW AND RESPECTABLE CAA SHOULD KEEP SNOW FLYING IN THE N-CNTRL MTNS AT LEAST THRU THIS EVENING. THEREFORE WILL EXTEND THE SNOW/BLOWING SNOW ADVSY FOR MTN ZONES 31..33 AND 34 UNTIL 06Z/ TONIGHT. CAME UP WITH ANOTHER 4-8 INCHES DURING THE NEXT 18 HOURS USING OUR LOCAL OROGRAPHIC SNOW MODEL. BY THE WAY...COLD AIR TRAPPED IN THE MTN VALLEYS AND OVERLAID BY WARMER VERY MOIST AIR ALOFT HAS BEEN PRODUCING SOME FREEZING RAIN AROUND KREMMLING. MAY SEE THIS TYPE OF PCPN FOR A WHILE LONGER BEFORE CHANGING OVER TO SNOW WITH GREATER MIXING LATER THIS MORNING. AS FOR AREAS EAST OF THE MTNS...SWLY FLOW JUST OFF THE SFC HAS CONTINUED TO SQUELCH PCPN FORMATION. DID SEE SOME VERY LIGHT SNOW AT DENVER`S INTERNATIONAL AIRPORT AND A MIX OF LIGHT PCPN IN THE FAR NERN CORNER SEVERAL HOURS AGO...BUT NOT MUCH ELSE. EVEN WITH QG OMEGA FIELDS INDICATING AN INCREASE IN VERTICAL MOTION OVER THE AREA WITH LOW LEVEL CYCLOGENESIS LATER THIS MORNING...BELIEVE PCPN CHANCE WILL REMAIN LOW ON THE PLAINS. AS FOR THE FREEZING RAIN ADVSY...HAVE SWAPPED IT OUT FOR A WINTER WEATHER ADVSY WHICH WILL NOW COVER A FEW LESS COUNTIES IN THE FAR NERN CORNER OF THE STATE. FREEZING DRIZZLE...LGT SNOW AND FOG NOW APPEARS WILL BE MORE OF A HAZARD TO TRAVELERS OUT THERE THROUGH MID-MORNING. BY THIS AFTERNOON WITH THE SFC AND UPPER LOWS MOVING OUT AND LOW-LVL WINDS SWINGING AROUND TO A N-NWLY COMPONENT...SHOULD SEE FAIRLY RAPID CLEARING FROM THE FRONT RANGE EWRD. TEMPERATURES TODAY EXPECTED TO BE SEVERAL DEGS ABOVE THOSE OBSERVED YESTERDAY...BUT THE FAR NERN CORNER MAY NOT ENJOY MUCH OF THIS WARM-UP WITH LINGERING LOW CLOUDS AND CAA. .LONG TERM...THE FLOW ALOFT WILL BE WLY ON SUN WITH SOME LINGERING MOISTURE IN THE MTNS SO SHOULD SEE SOME LINGERING OROGRAPHIC -SHSN. OVER THE PLAINS IT SHOULD BE DRY WITH DOWNSLOPE NWLY LOW LEVEL FLOW IN PLACE. TEMPS ON SUN WILL BE COOLER THAN SAT AS SOME CAA OCCURS IN THE LOWER LEVELS. FOR SUN NIGHT INTO MON CROSS-SECTIONS SHOW A RATHER DRY AIRMASS OVER THE AREA AS AN UPPER LEVEL RIDGE BEGINS TO BUILD ACROSS THE RGN. TEMPS ON MON SHOULD RISE WELL INTO THE 50S TO POSSIBLY NEAR 60 ACROSS NERN CO AS LOW LEVEL FLOW COMES MORE WLY AND 850-700 MB TEMPS WARM FROM 5 TO 6 DEGREES C. BY TUE A FLAT UPPER LEVEL RIDGE WILL BE OVER THE AREA WHICH SHOULD LEAD TO A DRY AND MILD DAY. WITH DOWNSLOPE LOW LEVEL FLOW IN PLACE TEMPS SHOULD WARM INTO THE 60S ACROSS NERN CO. ON WED A WEAK UPPER LEVEL TROUGH WILL MOVE ACROSS IN DEVELOPING NW FLOW ALOFT WHICH MAY ALLOW FOR A SLIGHT CHC OF SOME -SHSN IN THE MTNS. MEANWHILE A WEAK CDFNT WILL AFFECT NERN CO ON WED WHICH MAY DROP TEMPS BY AROUND 10 DEGREES OR SO. CURRENT CROSS-SECTIONS SHOW LACK OF MOISTURE WITH THIS FNT SO WILL KEEP FCST DRY ON WED OVER THE PLAINS. FOR THU AND FRI THE LATEST GFS SHOWS WNW FLOW ALOFT ACROSS COLORADO WITH A FEW WEAK DISTURBANCES MOVING ACROSS WHICH MAY PRODUCE A CHC OF SNOW IN THE MTNS WITH DRY AND MILD CONDITIONS OVER NERN CO. && .AVIATION...A LITTLE FREEZING RAIN IS EXPECTED THROUGH 18Z BUT THE AMOUNT IS EXPECTED TO BE VERY LIGHT...MAYBE .01 OR .02 INCH. COLD AIR IS SHALLOW SO ICING THREAT IS MAINLY AT THE GROUND AND ABOVE 9000 FEET MSL AND MAINLY NORTH OF DIA. THE THREAT OF ANY SNOW IS LOW. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING THROUGH NOON FOR ZONE 32. SNOW AND BLOWING SNOW ADVISORY TODAY AND THIS EVENING UNTIL 06Z FOR THE NORTH-CENTRAL MOUNTAINS...ZONES 31..33 AND 34. FREEZING RAIN ADVISORY THROUGH NOON FOR ZONES 35..38 AND 43. FREEZING RAIN ADVISORY THROUGH 3 PM FOR ZONES 42..44..48>51. && $$ GIMMESTAD/BAKER/KLEYLA co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 400 AM MST SAT DEC 01 2007 .SHORT TERM...DEEP UPR LVL VORTEX OVR SRN CA AT THE BOTTOM OF A HIGH AMPLITUDE TROUGH NOW CROSSING THE GREAT BASIN. NEWRD PROGRESS OF THE UPR LOW APPEARS TO HAVE PICKED UP SPEED. BACK EDGE OF CLOUD SHIELD IN THE VICINITY OF THE MAIN CORT MAXIMA TIMED TO REACH NWRN AND CNTRL COLORADO BY AROUND MIDDAY. THAT MATCHES UP PRETTY CLOSELY WITH TIMING OF THE RUC...BUT MUCH QUICKER THAN THAT OFFERED BY THE NAM AND GFS. HOWEVER CAN`T IGNORE THE JET LEVEL ENERGY AND CAA STILL COMING DOWN THE BACK SIDE OF THE TROUGH. SUSPECT WE`LL SEE A RESURGENCE OF CLOUDS AND SNOWFALL LATER THIS MORNING ALONG AND WEST OF THE CONTINENTAL DIVIDE WITH PASSAGE OF THE 700-500 MB TROUGH AXIS. QG OMEGA FIELDS SHOWS AN AREA OF MODERATE UPWARD QG VERTICAL MOTION MOVING OVER THE AREA BY THIS AFTERNOON. FURTHERMORE A SHIFT TO W-NWLY FLOW AND RESPECTABLE CAA SHOULD KEEP SNOW FLYING IN THE N-CNTRL MTNS AT LEAST THRU THIS EVENING. THEREFORE WILL EXTEND THE SNOW/BLOWING SNOW ADVSY FOR MTN ZONES 31..33 AND 34 UNTIL 06Z/ TONIGHT. CAME UP WITH ANOTHER 4-8 INCHES DURING THE NEXT 18 HOURS USING OUR LOCAL OROGRAPHIC SNOW MODEL. BY THE WAY...COLD AIR TRAPPED IN THE MTN VALLEYS AND OVERLAID BY WARMER VERY MOIST AIR ALOFT HAS BEEN PRODUCING SOME FREEZING RAIN AROUND KREMMLING. MAY SEE THIS TYPE OF PCPN FOR A WHILE LONGER BEFORE CHANGING OVER TO SNOW WITH GREATER MIXING LATER THIS MORNING. AS FOR AREAS EAST OF THE MTNS...SWLY FLOW JUST OFF THE SFC HAS CONTINUED TO SQUELCH PCPN FORMATION. DID SEE SOME VERY LIGHT SNOW AT DENVER`S INTERNATIONAL AIRPORT AND A MIX OF LIGHT PCPN IN THE FAR NERN CORNER SEVERAL HOURS AGO...BUT NOT MUCH ELSE. EVEN WITH QG OMEGA FIELDS INDICATING AN INCREASE IN VERTICAL MOTION OVER THE AREA WITH LOW LEVEL CYCLOGENESIS LATER THIS MORNING...BELIEVE PCPN CHANCE WILL REMAIN LOW ON THE PLAINS. AS FOR THE FREEZING RAIN ADVSY...HAVE SWAPPED IT OUT FOR A WINTER WEATHER ADVSY WHICH WILL NOW COVER A FEW LESS COUNTIES IN THE FAR NERN CORNER OF THE STATE. FREEZING DRIZZLE...LGT SNOW AND FOG NOW APPEARS WILL BE MORE OF A HAZARD TO TRAVELERS OUT THERE THROUGH MID-MORNING. BY THIS AFTERNOON WITH THE SFC AND UPPER LOWS MOVING OUT AND LOW-LVL WINDS SWINGING AROUND TO A N-NWLY COMPONENT...SHOULD SEE FAIRLY RAPID CLEARING FROM THE FRONT RANGE EWRD. TEMPERATURES TODAY EXPECTED TO BE SEVERAL DEGS ABOVE THOSE OBSERVED YESTERDAY...BUT THE FAR NERN CORNER MAY NOT ENJOY MUCH OF THIS WARM-UP WITH LINGERING LOW CLOUDS AND CAA. .LONG TERM...THE FLOW ALOFT WILL BE WLY ON SUN WITH SOME LINGERING MOISTURE IN THE MTNS SO SHOULD SEE SOME LINGERING OROGRAPHIC -SHSN. OVER THE PLAINS IT SHOULD BE DRY WITH DOWNSLOPE NWLY LOW LEVEL FLOW IN PLACE. TEMPS ON SUN WILL BE COOLER THAN SAT AS SOME CAA OCCURS IN THE LOWER LEVELS. FOR SUN NIGHT INTO MON CROSS-SECTIONS SHOW A RATHER DRY AIRMASS OVER THE AREA AS AN UPPER LEVEL RIDGE BEGINS TO BUILD ACROSS THE RGN. TEMPS ON MON SHOULD RISE WELL INTO THE 50S TO POSSIBLY NEAR 60 ACROSS NERN CO AS LOW LEVEL FLOW COMES MORE WLY AND 850-700 MB TEMPS WARM FROM 5 TO 6 DEGREES C. BY TUE A FLAT UPPER LEVEL RIDGE WILL BE OVER THE AREA WHICH SHOULD LEAD TO A DRY AND MILD DAY. WITH DOWNSLOPE LOW LEVEL FLOW IN PLACE TEMPS SHOULD WARM INTO THE 60S ACROSS NERN CO. ON WED A WEAK UPPER LEVEL TROUGH WILL MOVE ACROSS IN DEVELOPING NW FLOW ALOFT WHICH MAY ALLOW FOR A SLIGHT CHC OF SOME -SHSN IN THE MTNS. MEANWHILE A WEAK CDFNT WILL AFFECT NERN CO ON WED WHICH MAY DROP TEMPS BY AROUND 10 DEGREES OR SO. CURRENT CROSS-SECTIONS SHOW LACK OF MOISTURE WITH THIS FNT SO WILL KEEP FCST DRY ON WED OVER THE PLAINS. FOR THU AND FRI THE LATEST GFS SHOWS WNW FLOW ALOFT ACROSS COLORADO WITH A FEW WEAK DISTURBANCES MOVING ACROSS WHICH MAY PRODUCE A CHC OF SNOW IN THE MTNS WITH DRY AND MILD CONDITIONS OVER NERN CO. && .AVIATION...VFR CNDTNS AT DENVER AREA AIRPORTS NEXT 24 HOURS. SCATTERED -SHSN THIS MORNING AND ISOLD -SHRA LATE MORNING AND AFTERNOON NOT EXPECTED TO PRODUCE MVFR CIGS OR VSBYS. && .BOU WATCHES/WARNINGS/ADVISORIES... .SNOW AND BLOWING SNOW ADVISORY TODAY AND THIS EVENING UNTIL 06Z FOR THE NORTH-CENTRAL MOUNTAINS...ZONES 31..33 AND 34. .WINTER WEATHER ADVISORY UNTIL 16Z THIS MORNING FOR PORTIONS OF NORTHEAST PLAINS...ZONES 42..48>51. && $$ BAKER/KLEYLA co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BILLINGS MT 401 AM MST SAT DEC 1 2007 .SHORT TERM...VALID FOR TDY AND SUN... EXPANDED THE HIGH WIND WARNING FOR SUNDAY AFTERNOON THROUGH MONDAY EVENING TO INCLUDE NORTHERN SWEET GRASS AND WHEATLAND COUNTIES. TRICKY FORECAST TODAY. MAIN PROBLEMS ARE WHERE AND HOW MUCH SNOW WILL FALL AND THEN BEGINNING SUNDAY AFTERNOON HOW STRONG WILL WINDS ACROSS THE AREA GET. MODELS CONTINUE TO STRUGGLE IN A BIG WAY WITH THE COLD AIR AND PRECIPITATION ACROSS THE AREA. BEST RESULTS CONTINUE TO BE LOOKING AT SHORT RANGE RUC AND WATCHING TRENDS. LATEST RUNS REALLY DIDN`T SHOW ANY PRECIPITATION OVER CENTRAL ZONES THIS MORNING...YET PICKING UP CLOSE TO HALF AN INCH ALREADY IN BILLINGS. THIS AREA APPEARS TO BE IN AN AREA OF MODERATE UPPER LEVEL DEFORMATION COMBINED WITH WEAK SURFACE CONVERGENCE. THIS IS ALL ON THE NORTHWEST SIDE OF AN ALREADY STRONG STORM SYSTEM PULLING OUT OF THE FOUR CORNERS AREA HEADED FOR THE CENTRAL PLAINS. MODEL INITIALIZATIONS SHOWED BOTH MODELS TOO FAR SOUTH AND EAST WITH 150KT JET STREAM. THUS MODEL RESULTS ARE SKEWED THAT DIRECTION. THIS MAY ACCOUNT FOR WHY THE EARLIER MODEL RUNS FAILED TO PICK UP ON THE PRECIPITATION CURRENTLY OCCURRING. 06Z WRF AND RUC ARE NOW INDICATING SOME LIGHT PRECIPITATION WHICH IS AN IMPROVEMENT. CURRENT THINKING HERE IS THAT THERE WILL BE TWO AREAS OF PRECIPITATION TO DEAL WITH THIS MORNING...MERGING INTO A SINGLE AREA LATER IN THE DAY. THE FIRST WILL BE OVER CENTRAL AND WESTERN ZONES. THE WESTERN EDGE OF THIS PRECIP WILL BE FROM NEAR LEWISTOWN TO HARLOWTON TO NORTHERN PARK COUNTY...WITH THE EASTERN EXTENT FROM NE ROSEBUD COUNTY TO SHERIDAN. THIS IS THE AREA OF UPPER DEFORMATION AND IT DOESN`T LOOK LIKE IT WILL MOVE VERY MUCH UNTIL LATE MORNING OR EARLY AFTERNOON WHEN UPPER STORM SYSTEM ACCELERATES OUT OF THE ROCKIES PULLING IT EAST. CURRENTLY HAVE ADDITIONAL SNOW ACCUMULATIONS IN THE VICINITY OF AN INCH BUT LOCALLY COULD SEE MORE THAN 2 INCHES IN SPOTS IF CURRENT LEVEL OF PRECIPITATION CONTINUES. AIRMASS IS PERFECTLY SET UP FOR STRONG DENDRITIC CRYSTAL GROWTH SO WILL HAVE TO WATCH ANY PERSISTENT BANDS CLOSELY FOR HIGHER ACCUMULATIONS. THE SECOND PRECIPITATION AREA WILL BE ISENTROPICALLY INDUCED OVER SOUTHEAST PORTIONS OF THE FORECAST AREA ALONG AND SOUTH OF A SHERIDAN TO BAKER LINE. LATEST WRF INCREASED QPF FOR THE AFTERNOON PERIOD TO NEAR A QUARTER OF AN INCH. LATE IN THE DAY THE UPPER LEVEL DEFORMATION AREA WILL SHIFT EAST INTO THIS AREA TO ENHANCE SNOWFALL RATES SO THESE NEW MODEL TOTALS MAY BE CLOSE. BUMPED UP ACCUMULATIONS TO AROUND 2 INCHES IN THE AFOREMENTIONED AREA AND WILL AGAIN HAVE TO WATCH CLOSELY FOR POSSIBLE ADVISORY CRITERIA SNOW AMOUNTS LATER TODAY. AGAIN WITH THE MODELS DOING VERY POORLY RIGHT NOW OVER OUR AREA CONFIDENCE IS PRETTY LOW TODAY. PRECIPITATION SHOULD END OVERNIGHT TONIGHT ACROSS SOUTHEAST ZONES AS MAIN SYSTEM PULLS WELL AWAY FROM THE AREA. THE DEEPENING SURFACE LOW TO THE SOUTH AND SOUTHEAST OF THE AREA WILL CONTINUE TO PULL COLDER CANADIAN AIR INTO THE AREA TODAY. THIS WILL LIKELY PRODUCE TEMPERATURES HOLDING PRETTY CLOSE TO MORNING LOWS TODAY...AND POSSIBLY DROPPING LATER IN THE DAY AS THE LOW SPINS UP OVER SOUTHERN WYOMING. TOMORROW WILL SEE A STRONG PACIFIC JET STREAM PUSH INTO THE AREA FROM THE WEST. THIS WILL BEGIN THE WARMING TREND AS DOWNSLOPE WINDS SCOUR OUT THE COLDER AIR ACROSS THE AREA. THIS STRONG JET STREAM WILL ALSO BE THE IMPETUS FOR STRONG SURFACE WINDS ALONG THE FRONT RANGE OF THE BEARTOOTH AND CRAZY MOUNTAINS. LATEST MODEL GUIDANCE FAVORABLE FOR WARNING TYPE WINDS BEGINNING SUNDAY AFTERNOON AND CONTINUING THROUGH EARLY TUESDAY MORNING. INCLUDED THE NORTHERN SWEET GRASS AND WHEATLAND COUNTY AREAS IN THE WATCH AS LATEST WRF INDICATING POTENTIAL FOR AN STRONG WINDS TO DESCEND CLOSE TO THE SURFACE IN THESE AREAS SUNDAY NIGHT. OTHER AREAS GETTING CLOSE TO NEEDING WATCH BASED ON WINDS WORKING TO THE SURFACE ARE THE RED LODGE FOOTHILLS AND THE EAST SIDE OF THE BIG HORN MOUNTAINS. INCREASED WINDS IN THESE AREAS TO JUST BELOW HIGHLIGHT CRITERIA. KEPT WATCH TIMING IN TACT BUT MAY NEED TO CONSIDER EXTENDING THE TIMING INTO THE DAY TUESDAY WITH ANY UPGRADES. CHAMBERS .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... FLAT RIDGE PROGGED OVER THE AREA MONDAY AND TUESDAY. STRONG WINDS WILL CONTINUE OVER THE WEST MONDAY AND MONDAY NIGHT WITH DEEP LEE TROUGH IN PLACE. RAISED WINDS A BIT MORE FOR MONDAY AND MONDAY NIGHT. THE TROUGH MOVES EAST TUESDAY AS THE ZONAL FLOW TRANSITION TO NORTHWEST WITH THE PASSAGE OF SHORTWAVE ENERGY. RAISED POPS A BIT AND PUSHED THEM EAST FOR MONDAY AS STRONG ENERGY CRESTS THE RIDGE WITH DECENT FRONTOGENESIS IN WARM AIR ADVECTION. THE GFS IS USUALLY PRETTY GOOD AT PICKING UP THESE PRECIPITATION PATTERNS AND ARE OFTEN INCORRECTLY DISCOUNTED DUE TO STRONG DOWNSLOPE INFLUENCES. RAISED POPS TO GUIDANCE VALUES. TEMPERATURES SHOULD MODERATE MONDAY AND TUESDAY WITH DOWNSLOPE FLOW. A SURFACE HIGH BUILDS INTO WESTERN NORTH DAKOTA WEDNESDAY AND BACK DOORS A COLD FRONT INTO THE FORECAST AREA. KEPT THE IDEA OF SCATTERED POPS OVER THE AREA WITH A SHORTWAVE MOVING DOWN IN NORTHWEST FLOW AND A BOUNDARY TO FOCUS ON. THE GFS WANTS TO BRING A RIDGE IN QUICKLY WEDNESDAY NIGHT...FOLLOWED BY SPLITTING PIECE OF ENERGY THURSDAY AND THURSDAY NIGHT. THE ECMWF WAS CONSISTENT WITH THE GFS IN THIS SOLUTION WITH THE SPEED BEING A LITTLE QUICKER. DID NOT CHANGE POPS MUCH AS MAIN FOCUS SHOULD BE WEDNESDAY AND WEDNESDAY NIGHT. PATTERN BECOMES QUITE PROGRESSIVE FOR THE END OF THE WEEK INTO NEXT WEEKEND. BLANKETED POPS THROUGH THE PERIOD WITH THE BEST SHOT LOOKING TO BE ON FRIDAY. TEMPERATURES SHOULD BE SEASONAL. HUMPHREY && .AVIATION... A BAND OF LIGHT SNOW OVER SOUTH CENTRAL MONTANA WILL PERSIST THROUGH THE MORNING HOURS. MVFR WITH OCCASIONAL IFR CONDITIONS CAN BE EXPECTED. MOUNTAINS WILL BE OBSCURED. THE SNOW WILL TAPER OFF THIS AFTERNOON AND CONDITIONS SHOULD RAISE TO VFR THEN. A DECK OF MID LEVEL CLOUDS SHOULD PERSIST THROUGH THE NIGHT TONIGHT. HUMPHREY && .PRELIMINARY POINT TEMP/POPS... TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 018 008/029 028/042 025/049 026/038 022/036 022/038 8/S 00/N 03/O 20/B 03/S 30/B 22/S LVM 018 011/035 035/046 035/048 026/038 022/036 022/038 8/S 20/N 23/O 20/N 03/S 30/B 32/S HDN 017 008/030 022/043 021/051 022/039 019/037 019/039 8/S 00/B 03/O 20/B 02/S 20/B 22/S MLS 018 004/025 021/038 022/046 023/033 019/031 019/033 6/S 00/B 00/B 00/B 02/S 20/B 02/S 4BQ 019 005/030 021/043 021/049 022/037 018/028 018/037 8/S 30/B 00/B 00/B 02/S 20/B 02/S BHK 019 002/025 017/037 021/043 022/031 018/028 012/030 6/S 20/B 00/B 00/B 02/S 20/E 02/S SHR 019 006/030 018/045 028/049 021/038 018/036 018/038 6/S 20/B 00/B 00/B 02/S 20/B 22/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...HIGH WIND WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY EVENING FOR ZONES 28-41-63-65-66. WY...NONE. && $$ WEATHER.GOV/BILLINGS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 608 AM PST SAT DEC 1 2007 .SYNOPSIS... A SERIES OF STORM SYSTEMS WILL BRING SIGNIFICANT AMOUNTS OF WINTRY PRECIPITATION TO THE PACIFIC NORTHWEST THIS WEEKEND INTO EARLY NEXT WEEK. THE HEAVIEST SNOW IS EXPECTED TO FALL OVER THE CASCADES AND INTO THE MOUNTAINS OF NORTHERN WASHINGTON AND NORTHERN IDAHO. PRECIPITATION IN THE VALLEYS IS EXPECTED TO TRANSITION TO RAIN LATE ON SUNDAY...WITH SOME POCKETS OF FREEZING RAIN. && .DISCUSSION... THE FORECAST HAS BEEN UPDATED FOR TODAY TO INCREASE SNOW CHANCES OVER THE EASTERN THIRD OF WASHINGTON INCLUDING SPOKANE AND PULLMAN. THE 06Z RUNS OF THE NAM AND GFS HAVE COME INTO GOOD AGREEMENT BRINGING A WEAK MIDLEVEL VORTICITY AXIS THROUGH EASTERN WASHINGTON THIS AFTERNOON. BOTH MODELS...AS WELL AS THE LATEST RUC...PRODUCE SOME LIGHT SNOW FROM COLVILLE TO RITZVILLE AND POINTS EAST. RELATIVELY WEAK FORCING SHOULD KEEP ACCUMULATIONS TO LESS THAN AN INCH. STRONGER FORCING WILL ARRIVE LATE IN THE EVENING THROUGH THE OVERNIGHT AS A MORE POTENT WAVE ROUNDS THE BASE OF THE DEEPENING UPPER TROUGH OFF THE BRITISH COLUMBIA COAST. /GKOCH && .AVIATION... AREAS OF LIGHT SNOW ARE EXPECTED THROUGH 03Z OVER THE EASTERN THIRD OF WASHINGTON. CEILINGS WILL TEMPORARILY DROP TO BETWEEN 2000 AND 3000 FEET IN THE SPOKANE...COEUR D`ALENE...AND PULLMAN AREA BETWEEN 18Z AND 00Z. A MORE SIGNIFICANT BAND OF SNOW IS EXPECTED TO DEVELOP BETWEEN 03Z AND 06Z ALONG AND NORTH OF INTERSTATE 90. VISIBILITIES AND CEILINGS WILL LIKELY DROP TO IFR THROUGH 12Z SUNDAY WITH MODERATE TO OCCASIONALLY HEAVY SNOW IN KEAT...KOMK...KGEG...KSFF... AND KCOE. ACCUMULATIONS ON RUNWAYS ARE ALSO EXPECTED IN THE AFOREMENTIONED AIRPORTS. /GKOCH && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 24 21 30 29 38 32 / 40 70 90 100 90 60 COEUR D`ALENE 23 20 30 28 36 31 / 40 80 90 100 100 60 PULLMAN 29 25 34 32 40 37 / 30 30 70 80 80 60 LEWISTON 33 29 39 34 45 39 / 30 20 60 80 70 50 COLVILLE 27 21 29 27 35 30 / 40 90 100 100 100 70 SANDPOINT 24 19 29 27 31 30 / 40 90 100 100 100 70 KELLOGG 28 23 33 28 36 33 / 40 80 100 100 100 80 MOSES LAKE 27 22 33 31 42 32 / 20 60 80 90 80 40 WENATCHEE 29 23 30 28 35 32 / 20 80 100 100 80 40 OMAK 25 17 29 26 32 28 / 20 90 100 100 90 50 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...WINTER STORM WARNING FROM 10 PM THIS EVENING TO 4 PM PST MONDAY FOR NORTHERN PANHANDLE. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR COEUR D`ALENE AREA. WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR CENTRAL PANHANDLE MOUNTAINS. WA...WINTER STORM WARNING FROM 10 PM THIS EVENING TO 4 PM PST MONDAY FOR NORTHEAST MOUNTAINS...OKANOGAN HIGHLANDS. WINTER STORM WARNING FROM 10 PM THIS EVENING TO 4 AM PST MONDAY FOR WATERVILLE PLATEAU...WENATCHEE AREA. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR SPOKANE AREA...UPPER COLUMBIA BASIN. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 4 PM PST MONDAY FOR EAST SLOPES NORTHERN CASCADES. WINTER STORM WARNING FROM 10 PM THIS EVENING TO 10 AM PST MONDAY FOR OKANOGAN VALLEY. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 227 PM MST SAT DEC 1 2007 .SHORT TERM... (TONIGHT AND SUNDAY) ...MAJOR WINTER STORM STILL TO AFFECT CO FOR NEXT 12-18 HOURS... ...WELL NEEDED SNOWPACK FORMING ACROSS THE CONTINENTAL DIVIDE... CURRENTLY...WELL ADVERTISED HIGH IMPACT WEATHER EVENT OCCURRING ACROSS MUCH OF THE AREA. TREMENDOUS MOISTURE CONTENT WITH SNOW AND RAINFALL ACROSS THE MOUNTAINS/HIGH VALLEYS FROM LAST NIGHT THROUGH THIS MORNING. AN NWS SPOTTER REPORTED 1.96 INCHES OF RAIN...ALL RAIN...6 WEST OF WESTCLIFFE ALONG THE EASTERN SLOPE OF THE SANGRE DE CRISTO MOUNTAINS AROUND 8700 FEET MSL. ALL RAIN WITH TEMPERATURES IN THE MID 30S LAST NIGHT AND THIS MORNING. A FEW LOWER ELEVATIONS ACROSS WESTERN CO RECEIVED UP TO A LITTLE OVER 3 INCHES OF RAINFALL. SANGRE DE CRISTO MOUNTAIN SNOTEL DATA...GENERALLY ABOVE 10K FT MSL...HAD SNOW WATER EQUIVALENT VALUES AROUND 1.00 INCH. LIKELY APPROACHING 3 FEET OF SNOW ACROSS THE EASTERN SAN JUAN MOUNTAINS HIGHER TERRAIN THIS AFTERNOON. EARLY AFTERNOON REPORT WAS 29 INCHES OF SNOW(5.40 INCH WATER) FOR WOLF CREEK...AND STILL SNOWING 1 INCH PER HOUR. LATEST WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED LONGWAVE TROUGH APPROACHING THE ROCKIES. SIGNIFICANT MIDDLE-UPPER LEVEL /DRY/SLOT HAS MOVED INTO THE EASTERN 1/2 OF CO WITH SOME HIGHER LEVEL MOISTURE STILL NOTED BACK IN THE RELATIVELY COLDER AIR ALONG AND WEST OF THE CONTINENTAL DIVIDE. REGIONAL RADAR HAS NOT SHOWING MUCH...EXCEPT SOME ISOLD-SCATTERED RAIN/SNOW SHOWERS ACROSS THE OUR EASTERN CO MOUNTAINS...BUT VERY SHALLOW CONVECTION. TEMPERATURE IN THE MOUNTAINS AND HIGH VALLEYS ARE STILL IN THE 30S/40S...SO ANY INTENSE CONVECTIVE PRECIPITATION WOULD LIKELY BE A MIXTURE OF RAIN/SNOW WITH POSSIBLY A QUICK 1 INCH OF SNOW IN HEAVIER SNOW BURSTS. LIVE WEBCAMS HAVE SHOWN SOME MINOR WEATHER IMPROVEMENT ACROSS WOLF CREEK AND MONARCH PASSES...BUT SNOW APPEARS TO BE CONTINUING AT THE HIGHER TERRAIN ABOVE THE HIGHWAYS. MEANWHILE... ALONG I-25 CORRIDOR AND EASTWARD...WINDY TO VERY WINDY CONDITIONS WERE OCCURRING. WIND GUSTS HAVE MAINLY 35-55 MPH...EXCEPT SOME 60-70 MPH WIND GUSTS AROUND LA VETA/WALSENBURG IN THE GAP FLOW. WE HAVE NOT REACHED HIGH WIND WARNING GUST CRITERION YET AND WILL BE CLOSE FOR THE CURRENT HIGH WIND WARNING. LA JUNTA JUST HAD A PEAK WIND OF 53KTS(60 MPH) AROUND 123 PM. ONCE THE WIND KICKED-IN...TEMPERATURES ACROSS THE SOUTHEAST CO PLAINS SHOT INTO THE 60S-LOWER 70S. GREATEST SURFACE PRESSURE FALLS ARE AROUND NORTHWEST KS PER MSAS DATA...SO SURFACE LOW TO LIKELY /JUMP/ TO THAT AREA THIS AFTERNOON/EARLY EVENING. LATE THIS AFTERNOON AND TONIGHT...NOT DONE WITH THE SYSTEM JUST YET. UPPER LEVEL LONGWAVE TROUGH IS PROJECTED TO MOVE THROUGH THE CENTRAL ROCKIES TONIGHT. THIS MIGHT KEEP THE WIND BLOWING...ESPECIALLY WINDY-VERY WINDY CONDITIONS ACROSS THE HIGH TERRAIN AND JUST WEST OF THE I-25 CORRIDOR TOWARDS THE MOUNTAINS. MIDDLE-UPPER LEVEL WINDS VEERING FROM SOUTHWEST TO WEST-NORTHWEST TONIGHT. THIS WOULD SHIFT THE MORE OROGRAPHIC ENHANCED QPF/SNOWFALL TO THE CENTRAL MOUNTAINS AND THE NORTH-SOUTH ORIENTED PART OF THE EASTERN SAN JUAN MOUNTAINS AROUND CUMBRES. PLAN TO CONTINUE WINTER STORM WARNING FOR EASTERN SAN JUAN...LA GARITA...AND COLLEGIATE MOUNTAINS HIGHER TERRAIN. WILL PROBABLY SEE ANOTHER FOOT OF SNOW OR SO FOR THE WOLF CREEK AREA...AND ANOTHER 6-12 INCHES FOR THE COLLEGIATE PEAKS. BLOWING SNOW WILL CREATE FOR HAZARDOUS WEATHER. EXTENDED THE SNOW AND BLOWING SNOW ADVISORY FOR LEADVILLE AND CLIMAX ZONES AS STEADY SNOW WILL LIKELY CONTINUE FOR THESE AREAS AS PRECIPITATION MOVES OFF THE COLLEGIATE PEAKS INTO THESE AREAS. ISOLATED-SCATTERED RAIN/SNOW SHOWERS WILL PROBABLY CONTINUE FOR OUR EASTERN CO MOUNTAINS WITH LOCAL ACCUMULATIONS OF 1-2 INCHES. SOUTHEAST CO WILL BE PRECIPITATION-FREE. WIND SPEEDS SHOULD DECREASE SOME ACROSS THE SOUTHEAST CO PLAINS. SUNDAY...STILL ANTICIPATING THE WEATHER TO QUIET-DOWN. RELATIVELY WEAKER WEST-NORTHWEST FLOW DEVELOPS OVER THE CENTRAL ROCKIES. MIDDLE LEVEL TEMPERATURES WILL BE MUCH COOLER THAN TODAY...SO SLIGHTLY COOLER TEMPERATURES ARE EXPECTED FOR SUNDAY. METZE .LONG TERM... (SUNDAY NIGHT THROUGH SATURDAY) TEMPERATURES...WINDS AND POTENTIAL FOR LATE WEEK/EARLY WEEKEND MAINLY WESTERN MOUNTAIN PRECIPITATION ARE THE PRIMARY METEOROLOGICAL CHALLENGES FOR THE LONG TERM. LONGER TERM COMPUTER MODELS INDICATE THAT ZONAL TO NORTHWEST FLOW ALOFT WILL BE IN PLACE OVER CWFA FROM SUNDAY NIGHT INTO THURSDAY...WHILE SOME WEAK UPSLOPE CONDITIONS DEVELOP OVER EASTERN SECTIONS WEDNESDAY. FROM FRIDAY INTO NEXT SATURDAY...FLOW ALOFT BECOMES MORE SOUTHWESTERLY AS CLOSED UPPER LOW DEVELOPS NEAR BAJA...WITH NEXT NORTHERLY SURGE ATTEMPTING TO PUSH INTO REGION BY LATER SATURDAY. FOR SENSIBLE WEATHER...EXPECT THAT HIGHEST POTENTIAL OF PRECIPITATION FOR THE CENTRAL AND WESTERN MOUNTAINS SHOULD OCCUR FROM LATER THURSDAY INTO SATURDAY WITH EASTERN SECTIONS OF THE CWFA REMAINING GENERALLY DRY...ALTHOUGH PRECIPITATION THREAT MAY BE INCREASING AGAIN BY LATE SATURDAY. WARMEST TEMPERATURES OF THE LONG TERM SHOULD BE NOTED MONDAY AND TUESDAY WITH COOLEST TEMPERATURES RETURNING BY NEXT SATURDAY...OVERALL MINIMUM AND MAXIMUM TEMPERATURES EXPECTED TO RUN ABOVE CLIMATOLOGICAL AVERAGES DURING THE LONG TERM. RELATIVELY LOW GRADE GRADIENT WINDS EXPECTED DURING THE LONG TERM WITH THE POSSIBLE EXCEPTIONS OF WEDNESDAY NIGHT AND FRIDAY NIGHT. && .AVIATION... PER SHORT TERM DISCUSSION...BREEZY-WINDY CONDITIONS WILL CONTINUE FOR ALL TAF LOCATIONS. THE WIND SHOULD DIMINISH BY TOMORROW. A FEW RAIN/SNOW SHOWERS MAY BE IN THE VICINITY OF KALS TONIGHT. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 6 PM MST THIS AFTERNOON FOR COZ093>099. SNOW AND BLOWING SNOW ADVISORY UNTIL 5 AM MST SUNDAY FOR COZ058-059-064. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 1105 AM MST SAT DEC 01 2007 .UPDATE...SHOWER BAND MOVED ACROSS THE AREA FASTER THAN EXPECTED SO I WILL CANCEL ALL OF THE ADVISORIES EXCEPT THE ONE FOR THE HIGHER MOUNTAINS. WEST WINDS OFF THE GROUND APPEAR TO BE DRYING SUFFICIENTLY TO KILL SHOWERS COMING OFF THE MOUNTAINS. I WILL STILL LEAVE LOW POPS EAST OF THE MOUNTAINS. A LITTLE LEERY OF THE DEVELOPING NORTHEAST WINDS...HOPING THEY WILL NOT GET TOO DEEP. SHIFTED TEMPERATURE GRADIENT SOUTHWARD...DENVER WILL BE ON THE EDGE OF THE COLD AIR THIS AFTERNOON. SO STILL LOW POPS FOR SOME MORE FREEZING PRECIP IN THE SOUTH PLATTE VALLEY. && .PREVIOUS DISCUSSION FROM 400 AM...DEEP UPR LVL VORTEX OVR SRN CA AT THE BOTTOM OF A HIGH AMPLITUDE TROUGH NOW CROSSING THE GREAT BASIN. NEWRD PROGRESS OF THE UPR LOW APPEARS TO HAVE PICKED UP SPEED. BACK EDGE OF CLOUD SHIELD IN THE VICINITY OF THE MAIN CORT MAXIMA TIMED TO REACH NWRN AND CNTRL COLORADO BY AROUND MIDDAY. THAT MATCHES UP PRETTY CLOSELY WITH TIMING OF THE RUC...BUT MUCH QUICKER THAN THAT OFFERED BY THE NAM AND GFS. HOWEVER CAN`T IGNORE THE JET LEVEL ENERGY AND CAA STILL COMING DOWN THE BACK SIDE OF THE TROUGH. SUSPECT WE`LL SEE A RESURGENCE OF CLOUDS AND SNOWFALL LATER THIS MORNING ALONG AND WEST OF THE CONTINENTAL DIVIDE WITH PASSAGE OF THE 700-500 MB TROUGH AXIS. QG OMEGA FIELDS SHOWS AN AREA OF MODERATE UPWARD QG VERTICAL MOTION MOVING OVER THE AREA BY THIS AFTERNOON. FURTHERMORE A SHIFT TO W-NWLY FLOW AND RESPECTABLE CAA SHOULD KEEP SNOW FLYING IN THE N-CNTRL MTNS AT LEAST THRU THIS EVENING. THEREFORE WILL EXTEND THE SNOW/BLOWING SNOW ADVSY FOR MTN ZONES 31..33 AND 34 UNTIL 06Z/ TONIGHT. CAME UP WITH ANOTHER 4-8 INCHES DURING THE NEXT 18 HOURS USING OUR LOCAL OROGRAPHIC SNOW MODEL. BY THE WAY...COLD AIR TRAPPED IN THE MTN VALLEYS AND OVERLAID BY WARMER VERY MOIST AIR ALOFT HAS BEEN PRODUCING SOME FREEZING RAIN AROUND KREMMLING. MAY SEE THIS TYPE OF PCPN FOR A WHILE LONGER BEFORE CHANGING OVER TO SNOW WITH GREATER MIXING LATER THIS MORNING. AS FOR AREAS EAST OF THE MTNS...SWLY FLOW JUST OFF THE SFC HAS CONTINUED TO SQUELCH PCPN FORMATION. DID SEE SOME VERY LIGHT SNOW AT DENVER`S INTERNATIONAL AIRPORT AND A MIX OF LIGHT PCPN IN THE FAR NERN CORNER SEVERAL HOURS AGO...BUT NOT MUCH ELSE. EVEN WITH QG OMEGA FIELDS INDICATING AN INCREASE IN VERTICAL MOTION OVER THE AREA WITH LOW LEVEL CYCLOGENESIS LATER THIS MORNING...BELIEVE PCPN CHANCE WILL REMAIN LOW ON THE PLAINS. AS FOR THE FREEZING RAIN ADVSY...HAVE SWAPPED IT OUT FOR A WINTER WEATHER ADVSY WHICH WILL NOW COVER A FEW LESS COUNTIES IN THE FAR NERN CORNER OF THE STATE. FREEZING DRIZZLE...LGT SNOW AND FOG NOW APPEARS WILL BE MORE OF A HAZARD TO TRAVELERS OUT THERE THROUGH MID-MORNING. BY THIS AFTERNOON WITH THE SFC AND UPPER LOWS MOVING OUT AND LOW-LVL WINDS SWINGING AROUND TO A N-NWLY COMPONENT...SHOULD SEE FAIRLY RAPID CLEARING FROM THE FRONT RANGE EWRD. TEMPERATURES TODAY EXPECTED TO BE SEVERAL DEGS ABOVE THOSE OBSERVED YESTERDAY...BUT THE FAR NERN CORNER MAY NOT ENJOY MUCH OF THIS WARM-UP WITH LINGERING LOW CLOUDS AND CAA. .LONG TERM...THE FLOW ALOFT WILL BE WLY ON SUN WITH SOME LINGERING MOISTURE IN THE MTNS SO SHOULD SEE SOME LINGERING OROGRAPHIC -SHSN. OVER THE PLAINS IT SHOULD BE DRY WITH DOWNSLOPE NWLY LOW LEVEL FLOW IN PLACE. TEMPS ON SUN WILL BE COOLER THAN SAT AS SOME CAA OCCURS IN THE LOWER LEVELS. FOR SUN NIGHT INTO MON CROSS-SECTIONS SHOW A RATHER DRY AIRMASS OVER THE AREA AS AN UPPER LEVEL RIDGE BEGINS TO BUILD ACROSS THE RGN. TEMPS ON MON SHOULD RISE WELL INTO THE 50S TO POSSIBLY NEAR 60 ACROSS NERN CO AS LOW LEVEL FLOW COMES MORE WLY AND 850-700 MB TEMPS WARM FROM 5 TO 6 DEGREES C. BY TUE A FLAT UPPER LEVEL RIDGE WILL BE OVER THE AREA WHICH SHOULD LEAD TO A DRY AND MILD DAY. WITH DOWNSLOPE LOW LEVEL FLOW IN PLACE TEMPS SHOULD WARM INTO THE 60S ACROSS NERN CO. ON WED A WEAK UPPER LEVEL TROUGH WILL MOVE ACROSS IN DEVELOPING NW FLOW ALOFT WHICH MAY ALLOW FOR A SLIGHT CHC OF SOME -SHSN IN THE MTNS. MEANWHILE A WEAK CDFNT WILL AFFECT NERN CO ON WED WHICH MAY DROP TEMPS BY AROUND 10 DEGREES OR SO. CURRENT CROSS-SECTIONS SHOW LACK OF MOISTURE WITH THIS FNT SO WILL KEEP FCST DRY ON WED OVER THE PLAINS. FOR THU AND FRI THE LATEST GFS SHOWS WNW FLOW ALOFT ACROSS COLORADO WITH A FEW WEAK DISTURBANCES MOVING ACROSS WHICH MAY PRODUCE A CHC OF SNOW IN THE MTNS WITH DRY AND MILD CONDITIONS OVER NERN CO. && .AVIATION...THREAT OF SHOWERS IS NOW LOW AND THE TEMPERATURE WILL LIKELY STAY AT OR ABOVE FREEZING THE REST OF THE DAY. WE MAY FLIRT WITH CEILINGS IN THE 4000-6000 FOOT RANGE AT TIMES THIS AFTERNOON... AT THIS POINT IT LOOKS LIKE HIGHER CEILINGS SHOULD PREVAIL. && .BOU WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY TODAY AND THIS EVENING UNTIL 06Z FOR THE NORTH-CENTRAL MOUNTAINS...ZONES 31..33 AND 34. && $$ GIMMESTAD co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PUEBLO CO 940 AM MST SAT DEC 1 2007 .UPDATE... ...MAJOR WINTER STORM CONTINUES TO AFFECT CO... QUICK UPDATE TO STAY AHEAD OF THE STORM AND SENSIBLE WEATHER CONDITIONS. CURRENTLY...AS ANTICIPATED THE LAST FEW DAYS QUITE A VARIETY OF WEATHER ACROSS SOUTHERN CO. ALREADY 1-2 FEET OF HEAVY WET SNOW ACROSS THE EASTERN SAN JUAN MOUNTAINS AND PARTS OF THE COLLEGIATE/MOSQUITO MOUNTAIN RANGES AND STILL SNOWING. SNOTEL DATA INDICATED AROUND 1.00 INCH OF SNOW WATER EQUIVALENT ACROSS THE SANGRE DE CRISTO MOUNTAINS HIGHER TERRAIN...GENERALLY ABOVE 10K FT MSL. MEANWHILE...HERE IS THE FASCINATING AND UNIQUE EVENT THAT OCCURRED IN DEC. AN NWS SPOTTER REPORTED 1.96 INCHES OF RAIN 6 WEST OF WESTCLIFFE ALONG THE EASTERN SLOPE OF THE SANGRE DE CRISTO MOUNTAINS AROUND 8700 FEET MSL. ALL RAIN WITH TEMPERATURES IN THE MID 30S LAST NIGHT AND THIS MORNING. TEMPERATURES ARE STILL RELATIVELY WARM AND MOIST ACROSS THE MOUNTAINS WITH AIR TEMPERATURES IN THE 30S AND 40S AND DEW POINTS IN THE 30S. ALSO...HAD SOME BRIEF FREEZING RAIN ACROSS PUEBLO COUNTY WITH THE RAIN AND SNOW SHOWERS COMING OFF THE MOUNTAINS AND RAIN MAKING IT THROUGH THE SHALLOW TRAPPED COLD AIR IN THE 20S ACROSS PUEBLO COUNTY. THE FREEZING RAIN NEVER MATERIALIZED ACROSS EL PASO COUNTY AND THE FAR SOUTHEAST CO PLAINS. TEMPERATURES DID CLIMB INTO THE 30S AND 40S ACROSS THE FAR SOUTHEAST CO PLAINS DURING LAST NIGHT. THE NEXT STORY IS WIND GUSTING TO 40-70 MPH AROUND LA VETA PASS AND INTO THE SOUTHERN FOOTHILLS THIS MORNING. LATEST WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED LONGWAVE TROUGH DIGGING ACROSS THE GREAT BASIN WITH DEEP SOUTHWEST FLOW OVER THE CENTRAL AND SOUTHERN ROCKIES. MIDDLE AND UPPER LEVEL /DRY/ SLOT IS BEGINNING TO WORK INTO NM AND SOUTHERN CO. THUS...REGIONAL RADAR DATA SHOWED ECHO RETURNS SIGNIFICANTLY DROPPING OFF. ANY SNOWFALL IS NOW LIKELY AROUND THE CONTINENTAL DIVIDE HIGHER TERRAIN. REST OF TODAY AND TONIGHT...WE STILL HAVE A WAYS TO GO IN DEALING WITH THIS STORM. NOW KIND OF PHASE 2....BELIEVE THE PRECIPITATION CHANCES HAS DIMINISHED SIGNIFICANT AROUND THE I-25 CORRIDOR AND EASTWARD GIVEN THE UPPER LEVEL /DRY/ SLOT WILL BE TAKING OVER. THERE STILL COULD BE ONE OR TWO SHOWERS ACROSS SOUTHEAST CO...BUT PRECIPITATION CHANCES ARE NOW VERY LOW OR NIL. CANCELLED THE FREEZING RAIN ADVISORY AROUND CANON CITY CONSIDERING IT IS APPROACHING 50F THERE. SINCE CANON CITY IS NEAR THE MOUNTAINS...THEY STILL COULD SEE A FEW RAIN AND SNOW SHOWERS. IT STILL LOOKS LIKE A VERY WINDY TO DAMAGING WIND GUSTS DAY FROM THE SOUTHERN FOOTHILLS TO THE SOUTHEAST CO PLAINS WITH WIND GUSTS OF 45-65 MPH. LA VETA IS LIKELY GETTING SOME ENHANCED GAP FLOW WITH WIND GUSTS OF 70 MPH...BUT THAT IS STILL BELOW THE WARNING CRITERIA. THE MAIN FOCUS FOR SNOWFALL...HEAVY AT TIMES AND BLOWING...WILL BE AROUND THE CONTINENTAL DIVIDE. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MST THIS AFTERNOON FOR COZ058-059-064. HIGH WIND WARNING UNTIL 6 PM MST THIS AFTERNOON FOR COZ093>099. WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ073-075. WINTER STORM WARNING UNTIL 5 AM MST SUNDAY FOR COZ060-061-066- 068. SNOW AND BLOWING SNOW ADVISORY UNTIL NOON MST TODAY FOR COZ067. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 330 PM EST SAT DEC 01 2007 .SYNOPSIS... ARCTIC HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT ALLOWING FOR TEMPERATURES TO DROP BACK INTO THE SINGLE DIGITS AND LOWER TEENS. HOWEVER...A COMPLEX YET POTENT STORM SYSTEM ADVANCING NORTHEAST FROM THE PLAINS WILL IMPACT THE REGION SUNDAY THROUGH MONDAY. WHILE THE EXACT TRACK REMAINS IN QUESTION...A WINTERY MIXTURE OF SNOW...SLEET...FREEZING RAIN IS EXPECTED. ONCE THIS SYSTEM TRACKS AWAY FROM THE REGION...STRONG WINDS ARE EXPECTED THROUGH MOST OF MONDAY WITH FALLING TEMPERATURES AND ADDITIONAL SNOW SHOWERS. && .NEAR TERM /TONIGHT/... INTERESTING MESOSCALE FEATURES AS COLD/DRY AIR DRAINAGE IS UNDERWAY WITH LATEST SURFACE OBSERVATIONS AND LAPS DATA SHOWING DUE NORTH WINDS FUNNELING DOWN INTO THE HUDSON VALLEY. DEWPOINTS HAVE RESPONDED WITH CURRENT READINGS BELOW 0F. HOWEVER...UPSTREAM CI/CS FROM PENDING STORM SYSTEM IS FAST APPROACHING. SO THIS SHOULD RESULT IN AN INITIAL DROP IN THE TEMPERATURE DEPARTMENT WITH TEMPERATURES REMAINING STEADY AND/OR SLOWLY RISING OVERNIGHT. CURRENT PROJECTIONS FROM THE RUC AND UPSTREAM TIMING FROM THE EXPANDING AREA OF PRECIP...PLACES THE WESTERN SECTIONS OF THE CWA (CATSKILLS...WESTERN MOHAWK VALLEY AND WESTERN ADIRONDACKS) WITH A CHANCE FOR LIGHT SNOW TOWARD DAYBREAK. MOST OF THIS IS EXPECTED TO FALL AS VIRGA WITH THE AFOREMENTIONED DRY LOW LEVELS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE WINTER STORM...CURRENTLY LOCATED NEAR THE FOUR CORNERS OF THE SOUTHWEST UNITED STATES...WILL MAKE A BEELINE NORTHEAST TO LAKE MICHIGAN BY SUNDAY MORNING. STRONG ISENTROPIC LIFT...WELL AHEAD THE SURFACE WARM FRONT...WILL ATTEMPT TO MOVE IN AS EARLY AS SUNDAY MORNING. WITH A VERY DRY AIR MASS IN PLACE...AND SOME SUGGESTION OF ADDITIONAL LOW LEVEL DRY AIR ADVECTION...THE SNOW WILL INITIALLY DRY UPON FALLING (VIRGA) AND THIS WOULD LIKELY CONTINUE INTO THE MIDDAY HOURS. PRECIPITATION ASSOCIATED WITH THIS STORM...WAS ALREADY WORKING INTO IN THE WESTERN GREAT LAKES REGION THIS AFTERNOON. AFTER THAT...THE COLUMN SHOULD SATURATE ENOUGH TO ALLOW SNOW TO REACH THE GROUND. WE STILL THINK PRECIPITATION SHOULD START AS MOSTLY SNOW (WITH PERHAPS A TOUCH OF SLEET) WELL SOUTH OF ALBANY SOMETIME DURING THE AFTERNOON. THE BRUNT OF THE PRECIPITATION WITH THE STORM LOOKS TO ARRIVE AFTER DARK ON SUNDAY. THIS TIME...THE LOW CENTER WILL BE DRIFTING MORE TO THE EAST...AS IT ENCOUNTERS TOO MUCH COLD AIR AND HIGH PRESSURE FURTHER NORTH...WORKING INTO WESTERN NEW YORK STATE AROUND MIDNIGHT...THEN STALLING SOMEWHERE IN THE SAINT LAWRENCE VALLEY. THE LEFT FRONT QUAD OF THE UPPER AIR JET...NOT SHABBY AT AROUND 100 KTS...WILL MOVE OVER OUR REGION AHEAD THE SURFACE CYCLONE OVERNIGHT SUNDAY. DIVERGENCE FROM THIS JETSTREAK...WILL INTERACT WITH VORTICITY SPIRALING TO THE THE TRIPLE POINT OCCLUSION...TO REAP A SECONDARY COASTAL STORM INITIALLY OFF THE JERSEY COAST. THIS SECONDARY STORM WILL QUICKLY SPIN UP...AS THE ORIGINAL SURFACE STORM GETS "CHOKED" OFF FROM THE WARM CONVEYOR BELT. BY MONDAY AFTERNOON...THIS STORM LOOKS TO HAVE DEEPEN AT LEAST 10MB FROM THE MORNING HOURS AS IT PASSES EAST OF CAPE COD. THE STORM WILL FURTHER DEEPEN AS IT MOVES INTO THE GULF OF MAINE BY LATE MONDAY. AS THIS POINT...WE DO BELIEVE FRONTOGENTIC FORCING WILL NOT BE EXCESSIVE OVER OUR REGION AS THE H7 LEVEL REMAINS PROGRESSIVE...AS OPPOSED TO CUTTING OFF...AT LEAST ACROSS OUR REGION. THAT IS NOT TO SAY THERE WILL BE NO ENHANCED UPWARD MOTION AND SOME FRONTOGENTIC FORCING...JUST NOT EXCESSIVE. THE MOST CHALLENGING PORTION OF THE FORECAST WILL BE THE ULTIMATE PTYPES THAT WILL TAKE PLACE SUNDAY NIGHT. ALL THE OPERATIONAL MODELS WE LOOKED AT THUS FAR...NAM/GFS/UKMET AND CANADIAN MODELS...INDICATE MOST IF NOT ALL SNOW WILL FALL UP WELL NORTH AND WEST OF ALBANY. SOUTH OF A BENNINGTON...GLENS FALLS...JOHNSTOWN LINE...THE CHALLENGE OF PTYPES INCREASES GREATLY. THE NAM REMAINS A BIT COLDER THAN THE GFS...BUT BOTH MODELS CONTINUE TO TREND SLIGHTLY WARMER IN THE COLUMN. HOWEVER...ALL MOS MACHINE GENERATED TEMPERATURES REMAIN AT BELOW FREEZING DURING THE EVENT FROM ALBANY NORTH. THE MET DOES THE SAME FOR POUGHKEEPSIE...WHILE THE MAV NUMBERS DO NOW POP UP BRIEFLY ABOVE THE FREEZING MARK TOMORROW. THE NAM MODEL SOUNDINGS SUGGEST A SNOW/SLEET MIX FROM THE MOHAWK RIVER SOUTH TO THE UPPER MID HUDSON VALLEY...WITH FREEZING RAIN AND EVEN BRIEFLY GOING TO LIQUID RAIN DOWN NEAR POUGHKEEPSIE. THE GFS MODEL SOUNDINGS WERE A BIT WARMER ALOFT...SUGGESTING FREEZING RAIN COULD EASILY MAKE INTO THE CAPITAL DISTRICT AND AFTER AN EXTENSIVE PERIOD OF FREEZING RAIN...WOULD GO TO LIQUID RAIN IN THE MID HUDSON VALLEY. THE CHANGE OF COUPLE OF DEGREES IN THE COLUMN WILL CREATE A DIFFERENCE IMPACT ON WHAT TYPE OF PRECIPITATION WOULD FALL. ERGO...THERE COULD BE HUGE VARIATIONS ON SNOW/SLEET ACCUMULATIONS AND OR ICING ACCRETIONS ACROSS MOST OF OUR REGION. ONCE THE SECONDARY STORM MOVES TO OUR EAST...THE COLUMN WILL QUICKLY COOL DOWN AND MOST PRECIPITATION THAT CONTINUES TO FALL WELL AFTER 12Z MONDAY WOULD BE IN THE FORM OF SNOW. MOST IF NOT ALL PRECIPITATION SHOULD SHUT DOWN TO OUR SOUTH BY MIDDAY...LINGERING SNOW COULD PERSIST FROM THE CAPITAL DISTRICT NORTH A LITTLE LONGER. IN FACT...AS THE SECONDARY WINDS UP...THE COLD CONVEYOR BELT/TROAL COULD ENHANCE SNOW ACROSS THE NORTHERN SECTION. BY THIS TIME...THIS REGION WILL LIKELY COME UNDER THE FAVORABLE SNOW GROWTH REGION. BEFORE THIS TIME NO ONE IN OUR AREA IS THE FAVORABLE SNOW GROWTH REGION...AS IT REMAINS ELEVATED ABOVE THE AREA OF MAXIMUM UPWARD MOTION. THE MODELS DO APPEAR TO BE CONVERGING ON LIQUID EQUIVALENT PRECIPITATION AMOUNTS WHICH APPEAR TO RANGE FROM AROUND AN INCH OR SO ACROSS THE CWA THROUGH THE END OF MONDAY. SINCE WE FEEL THE MOST CONFIDENT OF SIGNIFICANT SNOWFALL TO OUR NORTHWEST...WE WILL ISSUE WARNINGS THERE. ELSEWHERE...SINCE THERE ARE STILL TOO MANY METEOROLOGICAL UNCERTAINTIES...WE WILL LEAVE THE WINTER STORM WATCH IN PLACE. && .LONG TERM /TUESDAY THROUGH SATURDAY/... IN THE WAKE OF THE FIRST REAL WINTER STORM...ANOTHER SURGE OF ARCTIC AIR WILL BLAST INTO THE REGION. LOW LEVEL WINDS...EG 850 AND 925 HPA...WILL BE FAVORABLE FOR LAKE EFFECT SNOW...WITH WINDS LETTING UP IN THE EVENING. SNOW WILL BE HEAVIEST IN THE WESTERN MOHAWK VALLEY AND WESTERN ADIRONDACKS...DIMINISHING AS ONE GOES EAST. WINDS ARE LIKELY TO FUNNEL SOME OF THE CLOUDS AND SNOW SHOWERS DOWN THE MOHAWK VALLEY TO THE CAPITAL REGION AND SOME TERRAIN ENHANCED SNOW MAY OCCUR OVER THE TACONICS AND BERKSHIRES EAST OF ALBANY. A BRIEF PAUSE IN THE ACTION ON WEDNESDAY AS THE STORM FROM THE WEEKEND CONTINUES TO MOVE EAST INTO THE OCEAN WITH A SECOND LOW CENTER RACING ACROSS THE OHIO VALLEY TO THE MID ATLANTIC COAST. THE GOOD NEWS IS THAT THE GFS MODEL AND NCEP BOTH AGREE THAT THE LOW OFF THE MID ATLANTIC COAST WILL TAKE A BIT MORE SOUTHERLY PATH AND SHOULD HEAD OUT TO SEA BEFORE IT TURNS FAR ENOUGH NORTH TO AFFECT OUR WEATHER. MEANWHILE HIGH PRESSURE SLIDES EAST INTO THE OHIO VALLEY BY MIDDAY THURSDAY...AND TO THE VICINITY OF CAPE HATTERAS BY FRIDAY MORNING. HOWEVER SOME LAKE EFFECT SNOW MAY START UP THURSDAY AND PERSIST THURSDAY NIGHT...BUT WINDS WILL SHIFT TO A MORE SOUTHERLY DIRECTION BY FRIDAY MORNING WHICH WILL SHUT OFF THE LAKE EFFECT MACHINE. ON FRIDAY OVERRUNNING WARMER AIR MAY BRING ABOUT SOME LIGHT SNOW OVER THE REGION. TEMPERATURES WILL CONTINUE FIVE TO TEN DEGREES BELOW NORMAL. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... GUSTY SOUTHERLY WINDS TO 30 MPH WILL DIMINISH AFTER DARK. MVFR STRATUS WILL EVENTUALLY ENCROACH ALL OF OUR TERMINALS SHORTLY AFTER DARK AS WELL. ISOLATED SHOWERS...ASSOCIATED WITH A COLD FRONT...WILL PROBABLY NOT PRODUCE ANY PROBLEMS AT THE TAFS THROUGH THE EVENING. THEN...A STEADY RAIN IS POISED TO OVERSPREAD THE REGION OVERNIGHT AS LOW PRESSURE DEVELOPS ALONG A SLOWING COLD FRONT. THE RAIN COULD FALL MODERATELY AT TIMES...ESPECIALLY DURING THE MORNING COMMUTE PERIOD. AT THAT TIME...WE EXPECTED CEILINGS TO DIP TO BELOW THE IFR THRESHOLD AND THEY MIGHT JUST STAY THERE A GOOD PORTION OF THE DAY. OUTLOOK... THU NIGHT AND FRI...VFR-MVFR WITH SCT -SHRA/-SHSN. FRI NIGHT THRU SUN...VFR WITH WDLY SCT -SHSN. && .HYDROLOGY... COMPLICATED FORECASTING SITUATION COMING UP WITH THE WINTER STORM BRINGING SNOW MIXING AND/OR CHANGING TO RAIN/FREEZING RAIN. THE AREA MOST LIKELY TO SEE SIGNIFICANT RUNOFF INTO THE RIVERS WOULD BE TRIBUTARIES TO THE HUDSON RIVER IN ULSTER AND DUTCHESS COUNTIES ALONG WITH THE LOWER HOUSATONIC RIVER AND ITS TRIBUTARIES IN CONNECTICUT. COMPLICATING THIS SITUATION WILL BE HOW MUCH SNOW WILL FALL BEFORE WARMING ALOFT TURNS THE PRECIPITATION TO RAIN...AND HOW WARM IT WILL GET OVER THE HIGHER TERRAIN. CURRENT INDICATIONS ARE THAT SNOW ON THE GROUND WILL SOAK UP MUCH OF THE RAIN...PERHAPS RELEASING SOME OF IT GRADUALLY STARTING MONDAY MORNING UNTIL THE COLD AIR POURS INTO THE REGION MONDAY EVENING AND PUTS THE MELTING PROCESS TO AN END. IF THERE IS A PROLONGED PERIOD OF FREEZING OR SLEET...MOST OF THE MOISTURE WILL BE HELD ON THE GROUND AS ICE. IN THIS TYPE OF A STORM THERE ARE A LOT OF UNCERTAINTIES AND WE CANNOT RULE OUT THE POSSIBILITY OF FLOODING SHOULD MORE WARM AIR GET DRAWN INTO THE STORM... RAINFALL IS HEAVIER THAN EXPECTED...AND TEMPERATURES RISE INTO THE MID OR UPPER 40S. THE LAST SEVERAL MODEL RUNS SUGGEST THAT IT WILL ONLY GET A FEW DEGREES ABOVE FREEZING FOR SEVERAL HOURS MIDDAY MONDAY...AND THUS RIVER RESPONSE WILL BE LIMITED. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR CTZ001-013. NY...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR NYZ039-040-047>054-058>061-063>066. WINTER STORM WARNING FROM 12 PM SUNDAY TO 7 PM EST MONDAY FOR NYZ032-033-038-041>043-082>084. MA...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR MAZ001-025. VT...WINTER STORM WARNING FROM 12 PM SUNDAY TO 7 PM EST MONDAY FOR VTZ013>015. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...HWJIV LONG TERM...RCK AVIATION...EH HYDROLOGY...RCK WWW.WEATHER.GOV/ALBANY ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1045 AM CST SAT DEC 1 2007 .UPDATE... MADE MINOR CHANGES TO GOING FORECAST IN POP/WEATHER GRIDS TO FINE TUNE WITH CURRENT CONDITIONS. BASIC THEME OF THE FORECAST REMAINS UNCHANGED HOWEVER. FREEZING RAIN STRETCHES ALL THE WAY DOWNSTREAM TO THE NORTHWEST ONE-QUARTER TO ONE-THIRD OF MO BASED ON RADAR AND SURFACE OBS. THE LATEST RUC RUN SUGGESTS WE MAY BE AN HOUR OR TWO TOO FAST ON THE CHANGEOVER TO RAIN. ICE ACCUM REPORTS ARE STARTING TO NEAR THE 1/4 INCH MARK.N IF WINDS PICK UP AS EXPECTED...WE COULD START TO SEE SOME POWER LOSSES. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BENTON- BUCHANAN-CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-LINN. ICE STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR DES MOINES- HENRY IA-JEFFERSON-LEE-VAN BUREN. ICE STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CEDAR-IOWA- JOHNSON-KEOKUK-LOUISA-MUSCATINE-SCOTT-WASHINGTON. IL...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CARROLL-JO DAVIESS-STEPHENSON-WHITESIDE. ICE STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR HANCOCK- HENDERSON-MCDONOUGH-WARREN. ICE STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BUREAU-HENRY IL- MERCER-PUTNAM-ROCK ISLAND. MO...ICE STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR CLARK- SCOTLAND. && $$ WOLF ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 345 PM EST SAT DEC 1 2007 .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS A DEEPENING UPR TROF OVER THE W...WITH A PROGRESSIVE UPR RDG MOVING INTO THE UPR GRT LKS IN THE WAKE OF TROFFING EXITING SE CAN. SFC LO PRES IS TAKING SHAPE OVER THE WCNTRL PLAINS DOWNSTREAM OF THE WRN TROF. ALTHOUGH 12Z GRB/ MPX RAOBS SHOW VERY DRY LLVL AIR WAS PRESENT OVER THE UPR MIDWEST/ GRT LKS...SURGE OF WARM/MOIST AIR SHOWN BEST BY THE 12Z H85 RAOBS IN STRONG WAD REGIME BTWN DVLPG LO AND DEPARTING SFC HI OVER THE SE GRT LKS HAS CAUSED SN TO SPREAD QUICKLY TO THE NE THIS MRNG AND AS FAR NE AS AIT IN NCNTRL MN TO LSE BY 16Z. H85 DWPT CLOSE TO 10C NEAR MKC WITH SW WINDS AT H85 TO 50 KTS. PCPN MARCH TO THE NE HAS ALSO BEEN AIDED BY UPR DVGC IN RRQ OF UPR JET ACRS SE CAN. && .SHORT TERM DISCUSSION (TNGT AND SUNDAY)... MAIN FCST CONCERNS IN THIS PD ARE SN AMTS/POTENTIAL FOR MIXED PCPN/ GOING HEADLINES ASSOCIATED WITH DVLPG STORM IN THE CNTRL PLAINS. NAM/GFS HAVE COME INTO GOOD AGREEMENT ON THE EVOLUTION OF THE SFC MSLP FIELD TO UNFOLD THE NEXT 24 HRS. THIS GUIDANCE FCSTS THE PRIMARY LO CENTER TO TRACK FM NEAR OMA AT 00Z TO NRN LWR MI BY 00Z MON...WITH INVERTED TROF EXTENDING NWWD FM THE MAIN LO INTO THE CWA IN RESPONSE TO APRCH OF ANOTHER SHRTWV THRU THE NRN PLAINS. THE MAIN IMPACT OF THIS MORE SRN TRACK...WHICH MAKES SENSE GIVEN THE VERY COLD LLVL AIR IN PLACE ACRS THE UPR LKS...WL BE LESS MIXED PCPN AND MORE SN THAN PREVIOUSLY FCST...WITH BULK OF MIXED PCPN PROBABLY RESTRICTED TO THE FAR S FM SRN MNM COUNTY TO THE GARDEN PENINSULA. CURRENT TRENDS SUG SN WL RPDLY OVERSPREAD THE FA SW-NE THIS AFTN/ EARLY EVNG AS NAM/GFS SHOW VIGOROUS DEEP ISENTROPIC LIFT ON THE 280-300K SFCS AND DVLPG UPR DVGC IN WHAT APPEARS TO BE COUPLED UPR JET BTWN RRQ OF FEATURE IN SE CAN AND EXIT REGION OF JET LIFTING OUT OF WRN TROF INTO THE CNTRL PLAINS THIS EVNG. GIVEN THE IMPRESSIVE MSTR RETURN NOTED IN THE PLAINS...PREFER THE SOMEWHAT HIER GFS FCST MSTR RETURN. GFS SHOWS 4 G/KG SPECIFIC HUMIDITY ON THE 295K SFC (ARND H725) ARRIVING OVER THE SRN TIER BY 06Z...SUPPORTING GENERAL SN FALL RATES OF 4"/6 HRS. FCST SSE FLOW SUGS SOME LK ENHANCEMENT PSBL OFF LK MI...SO WL BOOST RATES UP TO 6 INCHES/6 HRS IN AREAS FAVORED BY THIS FLOW IN THE 00Z-06Z PD ONCE LLVL DRY IS COMPLETELY ERODED. HOWEVER...BOTH GFS/NAM HINT DRY SLOTTING ALF WL OVERSPREAD THE CWA W-E AFT 06Z...CUTTING OFF THE BETTER DYNAMICS/MSTR FM THE BEST SN GROWTH LYR. THE RESULT WL BE A REDUCTION IN THE SN INTENSITY W-E AFT MIDNGT WITH POTENTIAL FOR SOME -FZDZ. AS MENTIONED ABV...WL RESTRICT MENTION OF OTHER MIXED PCPN TO JUST THE FAR S...WITH A CHGOVER TO SLEET OVER THE FAR SCNTRL PER WRMG OF THE COLUMN ABV FRZG ARND H7. BUT THE BULK OF THE PCPN SHOULD FALL AS SN EVEN THERE WITH WRMG OF THE COLUMN OCCURRING AFT BULK OF UVV HAS ENDED AND DRIER AIR MOVED IN ALF. AS FOR TEMPS...EXPECT READINGS TO BE STEADY OR SLOWLY RISE. ON SUN...TRACK OF UPR JET TO THE S FCST TO MAINTAIN MORE UPR DVGC/ DEEP LYR H85-5 QVECTOR CNVGC OVER THE E THAN FARTHER W. SO EXPECT STEADIER SN TO LINGER THERE THE LONGEST. INVERTED TROF EXTENDING WNW FM THE LO CENTER MOVING INTO NRN LOWER MI WL ALSO LIKELY SERVE AS A FOCAL POINT FOR STEADIER SN WITH THE NE FLOW OFF LK SUP ON THE NRN FLANK OF THIS FEATURE ACTING TO ENHANCE THE SN A BIT OVER THE NW. HOWEVER...TRACK OF SHRTWV TO THE N THAT IS HELPING TO STRENGTHEN THE INVERTED TROF WL LIMIT THE INTENSITY OF ANY WRAP ARND PCPN BY TENDING TO MAINTAIN THE DRIER AIR ALF. ALTHOUGH MODEL GUIDANCE SHOWS SFC TEMPS RISING INTO THE 30S AND ABV FRZG OVER THE SCNTRL ZNS...SUSPECT TEMPS ABV FRZG WL BE LIMITED TO VERY CLOSE TO LK MI/THE BAY OF GREEN BAY GIVEN CHILL OF ANTECEDENT AIRMASS THAT WL BE MAINTAINED ON THIS SIDE OF THE MAIN SFC LO TRACK. SINCE NO WRNGS HAVE VERIFIED YET...WL LEAVE GOING WSW HEADLINES AS IS FOR NOW TO AVOID ANY VERIFICATION PENALTY. IF ANY CHG NEEDS TO BE MADE...IT MIGHT BE TO END THE WRNG EARLIER OVER THE W AND PSBLY EXTEND THE WARNING OVER THE E ON SUN AFTN DEPENDING ON HOW QUICKLY LINGERING DYNAMICS DEPART. && .LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)... MUCH OF THIS PERIOD WILL BE DOMINATED BY LAKE SUPERIOR LAKE EFFECT SNOW SHOWERS...THANKS TO NORTH TO NORTHWESTERLY WINDS...PARTICULARLY SUNDAY NIGHT THROUGH THURSDAY MORNING ACROSS THE EASTERN UPPER PENINSULA. AT 00Z MONDAY THE STORMS SURFACE LOW WILL LIKELY BE POSITIONED ACROSS NORTHWEST TO WEST CENTRAL LAKE HURON. THE 00Z CANADIAN CONTINUES TO BE THE WESTERN MOST OF THE MODELS AND WILL NOT BE UTILIZED FOR THIS FORECAST. EVEN THE 00Z UKMET HAS FALLEN MORE INTO LINE WITH THE CONSENSUS...TRACKING TO EASTERN LAKE ONTARIO BY 12Z MONDAY. EITHER WAY...HIGH PRESSURE WILL BE SLOW TO MOVE IN BEHIND THIS LOW...AS IT STAYS ACROSS THE CENTRAL PLAINS AND IS ONLY ABLE TO PROTRUDE IN SLIGHTLY UNTIL TUESDAY AFTERNOON. EVEN THEN IT LOOKS LIKE A CLIPPER SYSTEM MAY SCOOT OVER THE DAKOTAS MONDAY NIGHT OR TUESDAY. MODELS ARE HAVING A HARD TIME WITH THIS FEATURE...WITH THE 06Z GFS MUCH QUICKER...AND DEEPENING THE LOW OVER THE INDIANA AND OHIO WEDNESDAY AFTERNOON. THIS IS NOT BACKED UP BY OTHER MODELS AND WILL BE DISCREDITED AFTER THIS POINT. FARTHER OUT INTO THE EXTENDED...FOR DAYS 4/WEDNESDAY THROUGH 7/SATURDAY...MUCH OF THE LARGE SCALE SIGNIFICANT WEATHER WILL BE LOCATED ACROSS THE WEST COAST AND THE PACIFIC. OTHER THAN SOME SMALL SCALE FEATURES...SURFACE HIGH PRESSURE WILL GENERALLY DOMINATE THE CENTRAL AND EASTERN UNITED STATES THROUGH FRIDAY. HPC GUIDANCE WAS ONCE AGAIN HEAVILY UTILIZED...FOR DAYS 3/4 TUE/WED THIS WAS THE ECMWF...AND FOR DAYS 5 TO 7 THU TO SAT A BLEND OF THE ECMWF AND THE 00Z GFS ENS MEAN. FORECAST CONFIDENCE IS MODERATE TO LOW BEYOND DAY 4/WEDNESDAY. AT 12Z SATURDAY FOR EXAMPLE...THE 06Z GFS SHOWS A 1032MB SURFACE HIGH OVER WESTERN WISCONSIN. AT THE SAME TIME...THE 00Z ECMWF HAS A 998MB LOW OVER CENTRAL WISCONSIN. THIS IS A SIGNIFICANT DIFFERENCE. SO...CHANGES TO THIS PERIOD MAINLY INCLUDED... ORIGINALLY THOUGHT THAT WE MAY NEED TO ALLOW FOR FALLING TEMPERATURES DURING THE DAY MONDAY. HOWEVER...LOOKING AT 850MB TEMPERATURES ACROSS THE REGION...THEY WILL BE SLOWLY BE INCREASING OVER SOUTHERN AND WESTERN UPPER MICHIGAN. FARTHER TO THE EAST...-15C SEEMS PRETTY ENTRENCHED OVER THAT AREA. IT LOOKS LIKE THE COLDEST AIR ALOFT -18C AT 850MB WEDNESDAY INTO EARLY WEDNESDAY EVENING. SEVERAL TWEAKS WERE MADE TO THE WINDS...WHICH RESULTED IN SMALL CHANGES TO LAKE EFFECT SNOW SHOWERS THROUGH MUCH OF THE TIME PERIOD. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... CONDITIONS AT BOTH TAF SITES SHOULD GO DOWNHILL FAST WITHIN THE NEXT FEW HOURS AS A LARGE AREA OF PRECIPITATION...IN THE FORM OF SNOW...WORKS INTO THE AREA. ONCE THE SNOW DOES DEVELOP EXPECT IT TO CONTINUE THROUGH THE TAF PERIOD AND BE HEAVY AT TIMES. SEE NO REASON WHY BOTH CMX AND SAW WONT REMAIN IN LIFR CONDITIONS FROM THIS EVENING THROUGH THE EARLY MORNING HOURS...WITH SLIGHT IMPROVEMENT BY SUNRISE. SOME CONCERN THAT BY LATER IN THE TAF PERIOD...8 TO 12Z...FREEZING DRIZZLE MAY DEVELOP AS DRY UPPER LEVEL DRY AIR WORKS INTO THE FORECAST AREA. THIS FREEZING DRIZZLE COULD CONTINUE THROUGH 18Z AS DRY AIR REMAINS ABOVE TAF SITES THROUGH THIS TIME. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... A LOW PRESSURE SYSTEM OF 29.2 INCHES OVER THE CENTRAL PLAINS TODAY WILL RACE NORTHEAST REACHING NORTHERN LAKE MICHIGAN SUNDAY AFTERNOON WHILE WEAKENING TO 29.6 INCHES. THE LOW WILL THEN RELOCATE OVER SOUTHEAST ONTARIO BY MONDAY MORNING AS A HIGH PRESSURE RIDGE OF 30.5 INCHES WORKS INTO THE UPPER MISSISSIPPI RIVER VALLEY. WITH THE LOW NEARBY...GALES WILL CONTINUE OFF AND ON...AND STILL REMAINING AROUND 30KT EAST HALF THROUGH MONDAY NIGHT. THE RIDGE WILL THEN MOVE TO THE LOWER GREAT LAKES WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM OF 29.9 INCHES MAKES ITS WAY FROM ALBERTA TO THE WEST END OF THE OHIO RIVER VALLEY. THE HIGH PRESSURE RIDGE WILL REMAIN OVER THE UPPER GREAT LAKES THROUGH THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WARNING UNTIL 1 PM EST /12 PM CST/ SUNDAY FOR MIZ002-009>013-084. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST SUNDAY FOR MIZ001-003>007-014-085. LAKE SUPERIOR...GALE WARNING UNTIL 5 PM EST SUNDAY FOR LSZ266-267. GALE WARNING FROM 9 PM THIS EVENING TO 6 AM EST SUNDAY FOR LSZ265. GALE WARNING FROM 9 PM THIS EVENING TO 5 PM EST SUNDAY FOR LSZ263-264. LAKE MICHIGAN...GALE WARNING UNTIL 7 AM EST SUNDAY FOR LMZ221-248-250. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...DJP MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 354 PM CST SAT DEC 1 2007 .DISCUSSION... STRONG WAA CONTINUES OVER THE EASTERN TWO-THIRDS OF THE CWA ATTM PER RUC/SREF PROGS. BEST SNOWFALL RUNS FROM WEST CENTRAL MN THROUGH CENTRAL MN TO WEST CENTRAL WI IN DEFORMATION ZONE. AXIS WILL BE SHIFTING NORTHEAST THIS EVENING AS DRY AIR BEGINS TO PLOW IN FROM THE SOUTHWEST. STILL CONCERNED ABOUT WEST CENTRAL MN THROUGH THE EVENING AS THE SHORT WAVE OVER SD/NE MOVES NORTHEAST ACROSS THE AREA. STRONG LAYER FWF IS DEPICTED ALONG WITH INSTABILITY ABOVE. SO A FEW MORE INCHES OF SNOW PROGGED. SLEET HAS DOMINATED OVER FAR SOUTHERN MN THROUGH MUCH OF THE DAY WITH SOME REPORT OF DEPTHS REACHING 4 INCHES. FREEZING RAIN IS NOW STARTED TO BE REPORTED HERE AND THERE ACROSS THE FAR SOUTH AS THE NOSE OF THE WARM LAYER ABOVE 0 DEG C IS LOWERING PER LAPS/RUC PROFILES. DECISION WAS TO LEAVE THE WARNING IN PLACE WITH VARIOUS PRECIP TYPES OCCURRING ALONG WITH 20 TO 25 MPH SUSTAINED WINDS. CHANGES WILL LIKELY BE MADE DURING THE EVENING. SMALL AREA OF DRYING ALOFT EVIDENT FROM THE TWIN CITIES ON SOUTHWEST TO FAIRMONT WHICH WILL DIMINISH PRECIPITATION INTENSITY. MORE SUBSTANTIAL DRYING ALOFT STILL EXPECTED LATER TONIGHT WITH SATURATED LOW LEVEL PROFILES AND TEMPERATURES RUNNING IN THE SINGLE DIGITS BELOW ZERO. FREEZING DRIZZLE STILL LOOKING GOOD. SOME SNOW SHOWERS ON SUNDAY AS ANOTHER SHORT WAVE MOVES ACROSS THE REGION. THE WEEK AHEAD FEATURES A STRONG CLIPPER MOVING SOUTHEAST ACROSS THE REGION TUESDAY AND TUESDAY NIGHT. GOOD CONTINUITY FROM DAY TO DAY ON THIS SYSTEM. RAISED POPS SOME MORE. WITH THE STORM TODAY TAKING A LOT OF OUR TIME...LATER SHIFTS MAY WANT TO BOOST POPS INTO THE LIKELY CATEGORY. YET ANOTHER SNOW EVENT SHAPING UP FOR NEXT WEEKEND PER THE ECMWF WHICH AGREED MORE WITH HPC THINKING OVER THAT OF THE GFS. THE EVENT NEXT WEEKEND IS ONE FROM THE SOUTHWESTERN U.S. SOME COLD NIGHTS IN BETWEEN THE VARIOUS SNOW EVENTS DURING THE NEXT SEVEN DAYS WITH SNOW NOW COVERING THE GROUND. NIGHTS WHERE SKIES ARE CLEAR TO PARTLY CLOUDY WILL LIKELY FEATURE LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. && .AVIATION... /18Z TAF ISSUANCE/ LIFR/VLIFR CEILINGS AND VISIBILITIES WILL PERSIST THROUGH THIS AFTERNOON. SNOW WILL BE THE DOMINANT WEATHER TYPE AT THE TAF SITES THIS AFTERNOON...ALTHOUGH THE SLEET/SNOW MIX ALONG THE MN/IA BORDER WILL GRADUALLY CREEP NORTHWARD. A PERIOD OF SLEET OR A SLEET/SNOW MIX WILL BE POSSIBLE AT KRWF/KMSP/KEAU...MAINLY BETWEEN 00Z AND 06Z. BRISK WINDS AT 15 TO 25 MPH WILL ALSO RESULT IN BLOWING AND DRIFTING SNOW THIS AFTERNOON AND TONIGHT. FREEZING DRIZZLE WILL ALSO BE POSSIBLE TONIGHT...MAINLY AT KEAU/KMSP/KSTC AFTER 06Z. CEILINGS WILL GRADUALLY IMPROVE TO THE MVFR CATEGORY BETWEEN 06Z AND 12Z. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS- FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WI...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR BARRON-CHIPPEWA- DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. && $$ RAH/LS mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 245 PM CST FRI NOV 30 2007 .SHORT TERM... MAIN PRECIP AREA HAS SHIFTED EAST OF THE CWA THIS AFTERNOON IN ASSOCIATION WITH UPPER MOTION FIELD. SOME LIGHT PRECIP CONTINUES ACROSS NORTHEAST NEBRASKA WHERE TEMPERATURES ARE HANGING AROUND FREEZING. WARM FRONT HAS PUSHED INTO SOUTHEAST NEBRASKA WHERE TEMPERATURES HAVE CLIMBED INTO THE 50S ALONG THE KANSAS BORDER. EXPECT WEDGE OF WARM AIR TO PUSH INTO EAST CENTRAL NEBRASKA AND SOUTHWEST IOWA BY 00Z BASED ON 15Z RUC13. RUC13 ALSO SUGGESTING BAND OF PRECIP IN ADVANCE OF COLD FRONT AS IT MOVES ACROSS SOUTHEAST PART OF THE CWA THIS EVENING. WILL CONTINUE TO CARRY SOME CHANCE POPS ACROSS ALL OF THE AREA THROUGH MIDNIGHT AS MID LEVEL WAVE APPROACHES AND SURFACE FRONT TRACKS SOUTHEAST. SOME CHANCE OF ISOLATED THUNDER YET IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA EARLY IN THE EVENING AS MID LEVEL INSTABILITY MOVES IN WITH SOME 850-700MB MOISTURE AROUND. LIGHT PRECIP EXPECTED TO LINGER ACROSS NORTHEAST NEBRASKA THIS EVENING SO PLAN ON CONTINUING HEADLINES FOR NOW AND CANCEL EARLY IF THINGS IMPROVE SOONER. COLDER AIR FOLLOWS BEHIND THE FRONT ON SUNDAY WITH FLURRIES POSSIBLE IN THE MORNING AS UPPER WAVE MOVES THROUGH...THEN CLEARING AS HIGH MOVES INTO THE REGION FOR SUNDAY NIGHT. TEMPERATURES LOOK TO WARM QUICKLY MONDAY AND TUESDAY AS WARM FRONT DEVELOPS IN ADVANCE OF CANADIAN CLIPPER THAT TRACKS INTO THE NORTHERN PLAINS. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY OVERALL LOW CONFIDENCE IN THE EXTENDED FORECAST WITH VARYING MODEL SOLUTIONS. THERE DOES APPEAR TO BE A BACKDOOR COLD FRONT THAT WILL MOVE THROUGH THE REGION ON WEDNESDAY WHICH SHOULD USHER IN COOLER TEMPS. DECIDED TO GO WITH A DRY FROPA FOR NOW AS MOISTURE AVAILABILITY MAY BE A CONCERN. BEYOND THAT...RELIED HEAVILY ON HPC GUIDANCE WHICH USED A BLEND OF 00Z ENSEMBLE MEAN AND ECWMF. THIS SCENARIO SUGGESTS THAT A NEW WEAK WAVE AND ASSOCIATED FRONTAL BOUNDARY WILL AFFECT THE AREA THURSDAY NIGHT THROUGH FRIDAY. WHILE THERE IS SOME SUPPORT FOR THIS IDEA FROM THE 12Z GFS...IT`S STILL NOT TOTALLY SUPPORTIVE OF THIS IDEA. THUS...HAVE ADDED SLIGHT CHANCE POPS MID WEEK FOR A MIXTURE OF RAIN AND SNOW...BUT THEN HAVE TRENDED DRY FOR SATURDAY. && .AVIATION... FOR KOFK...ZR IS EXPECTED TO CONTINUE INTO THE EVENING. ICING CONDITIONS WITH VISIBILITIES 2-4 MILES SHOULD CONTINUE THRU 06Z. MAIN ICING AREA IS EXPECTED PRIMARILY NORTH OF KBVN TO KSUX. SOUTH OF THIS AREA AT KOMA AND KLNK OCCASIONAL RAIN AND LOW CLOUDS WITH CEILINGS BELOW 1000 FEET ARE POSSIBLE. SOME VISIBILITIES MAY GO DOWN TO 1/4 MILE IN FG WITH STRONG SOUTH WINDS. WINDS WILL SWITCH TO NORTHWEST TONIGHT OVER MUCH OF THE AREA. CLOUD CEILINGS MAY IMPROVE DURING MORNING HOURS ON SUNDAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...ICE STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR NEZ011- 012-015>018-030>033. IA...NONE. && $$ FOBERT/DEWALD/SMITH ne AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE ALBUQUERQUE NM 1103 AM MST SAT DEC 1 2007 CORRECTED TIME OF UPDATE .UPDATE... UPGRADED TO A HIGH WIND WARNING IN THE CENTRAL AND SOUTH CENTRAL MOUNTAINS...AS WELL AS THE ADJACENT HIGH PLAINS OF LINCOLN AND SOUTHWEST CHAVES COUNTIES. ALSO ADDED A WIND ADVISORY TO THE NORTHWEST PLATEAU...WESTERN MOUNTAINS...SOUTHWEST MOUNTAINS...MIDDLE RIO GRANDE VALLEY AND LOWER RIO GRANDE VALLEY. SATELLITE IMAGERY SHOWS CLEARING BEHIND THE LINE OF STRONG SHOWERS THAT CROSSED CENTRAL AND WESTERN AREAS LAST NIGHT AND EARLY THIS MORNING. FURTHER...LATEST MODEL RUNS DEPICT 10K FT WIND SPEEDS IN THE 45 TO 55 KNOT RANGE...AND BOTH TEMPERATURES AND MIXING HEIGHTS WILL BE HIGHER THAN PREVIOUSLY EXPECTED TODAY. THUS...STRONGER SURFACE WINDS SHOULD RESULT. LEFT THE UPPER RIO GRANDE VALLEY OUT OF THE WIND ADVISORY BECAUSE GREATER CLOUD COVER IS EXPECTED NORTH OF ALBUQUERQUE. CLOUD COVER SHOULD ALSO PREVENT NORTHERN SAN JUAN COUNTY FROM REACHING WIND ADVISORY CRITERIA...BUT THE EAST SLOPES OF THE CHUSKA MOUNTAINS ACROSS SOUTHERN SAN JUAN COUNTY SHOULD SEE MORE SUN...BETTER MIXING AND STRONGER WINDS. MAIN FORECAST CHALLENGE FOR THE AFTERNOON FORECAST PACKAGE WILL BE WHETHER OR NOT TO EXTEND THE WINTER STORM WARNING FOR THE NORTHERN MOUNTAINS THROUGH TONIGHT. CHECK THE NEXT FORECAST UPDATE AT 4 PM MST TODAY FOR OUR DECISION. 44 && .PREV DISCUSSION... 300 AM MST SAT DEC 1 2007...DRY AIR ALREADY PUNCHING INTO SOUTHWEST ARIZONA...SO TAP OF SUBTROPICAL MOISTURE SHOULD BE SHIFTING EASTWARD DURING THE DAY TODAY. RUC INDICATES A FASTER TRANSITION TO COLDER TEMPS ALOFT THIS MORNING...CLOSER TO THE GFS...WHILE THE NAM HOLDS OFF WITH THE COLDER AIR UNTIL AFTER SUNSET TONIGHT. AS A NOTE...EARLIER RAIN HAD TRANSITIONED TO SNOW AT KGCN AS OF 09Z. ROUGHLY NORTHWEST THIRD TO HALF OF THE FORECAST AREA...NORTHWEST PLATEAU...WESTERN AND NORTHERN MOUNTAINS MAY EXPERIENCE ISOLATED THUNDER DURING THE DAY TODAY AS A MORE UNSTABLE PROFILE COULD RESULT. A 12 TO 16 MB SURFACE GRADIENT IS FORECAST TO DEVELOP ACROSS EASTERN NEW MEXICO THIS MORNING. WITH 50 KT WINDS SHOWING UP ON KTCC AND WSMR WIND PROFILERS TONIGHT...ENOUGH EVIDENCE FOR TODAY/S WIND HIGHLIGHTS TO REMAIN IN PLACE. CONCERNED LINCOLN COUNTY MAY TO BE UPGRADED...AS THEY MAY EXPERIENCE THE BETTER CLEARING TODAY. AREAS OUR WEST MAY ALSO BLOW CLOSE TO WIND ADVISORY TODAY. ENOUGH LINGERING MOISTURE MAY EXIST TO TURN ANY REMAINING RAIN TO SNOW OVER MUCH OF THE W...AS WELL AS THE CENTRAL AND SOUTH CENTRAL MOUNTAINS...CENTRAL HIGH PLAINS AND NE HIGHLANDS TONIGHT ONCE THE COLDER AIR ARRIVES. AN EXTENSION OR EXPANSION OF SOME SORT OF WINTER WEATHER HIGHLIGHTS MAY NEED TO BE ISSUED FOR SOME OF THESE AREAS ON LATER SHIFTS. THE WINDS AND PRECIPITATION WILL DIMINISH SUNDAY WITH ANY LINGERING PRECIPITATION CONFINED TO THE CENTRAL AND WEST. THE REST OF THE WEEK IS NOW LOOKING AS IF IT WILL BE DRY...WITH NO STORMS ON THE HORIZON UNTIL NEXT WEEKEND. && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES ABOVE 7500 FEET...NMZ002-004. HIGH WIND WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ005>007-010>013-016>017-026. WIND ADVISORY UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ001-008>009-014>015-018>021. && $$ 44 nm AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ALBUQUERQUE NM 300 AM MST SAT DEC 1 2007 .UPDATE... UPGRADED TO A HIGH WIND WARNING IN THE CENTRAL AND SOUTH CENTRAL MOUNTAINS...AS WELL AS THE ADJACENT HIGH PLAINS OF LINCOLN AND SOUTHWEST CHAVES COUNTIES. ALSO ADDED A WIND ADVISORY TO THE NORTHWEST PLATEAU...WESTERN MOUNTAINS...SOUTHWEST MOUNTAINS...MIDDLE RIO GRANDE VALLEY AND LOWER RIO GRANDE VALLEY. SATELLITE IMAGERY SHOWS CLEARING BEHIND THE LINE OF STRONG SHOWERS THAT CROSSED CENTRAL AND WESTERN AREAS LAST NIGHT AND EARLY THIS MORNING. FURTHER...LATEST MODEL RUNS DEPICT 10K FT WIND SPEEDS IN THE 45 TO 55 KNOT RANGE...AND BOTH TEMPERATURES AND MIXING HEIGHTS WILL BE HIGHER THAN PREVIOUSLY EXPECTED TODAY. THUS...STRONGER SURFACE WINDS SHOULD RESULT. LEFT THE UPPER RIO GRANDE VALLEY OUT OF THE WIND ADVISORY BECAUSE GREATER CLOUD COVER IS EXPECTED NORTH OF ALBUQUERQUE. CLOUD COVER SHOULD ALSO PREVENT NORTHERN SAN JUAN COUNTY FROM REACHING WIND ADVISORY CRITERIA...BUT THE EAST SLOPES OF THE CHUSKA MOUNTAINS ACROSS SOUTHERN SAN JUAN COUNTY SHOULD SEE MORE SUN...BETTER MIXING AND STRONGER WINDS. MAIN FORECAST CHALLENGE FOR THE AFTERNOON FORECAST PACKAGE WILL BE WHETHER OR NOT TO EXTEND THE WINTER STORM WARNING FOR THE NORTHERN MOUNTAINS THROUGH TONIGHT. CHECK THE NEXT FORECAST UPDATE AT 4 PM MST TODAY FOR OUR DECISION. 44 && .PREV DISCUSSION... 300 AM MST SAT DEC 1 2007...DRY AIR ALREADY PUNCHING INTO SOUTHWEST ARIZONA...SO TAP OF SUBTROPICAL MOISTURE SHOULD BE SHIFTING EASTWARD DURING THE DAY TODAY. RUC INDICATES A FASTER TRANSITION TO COLDER TEMPS ALOFT THIS MORNING...CLOSER TO THE GFS...WHILE THE NAM HOLDS OFF WITH THE COLDER AIR UNTIL AFTER SUNSET TONIGHT. AS A NOTE...EARLIER RAIN HAD TRANSITIONED TO SNOW AT KGCN AS OF 09Z. ROUGHLY NORTHWEST THIRD TO HALF OF THE FORECAST AREA...NORTHWEST PLATEAU...WESTERN AND NORTHERN MOUNTAINS MAY EXPERIENCE ISOLATED THUNDER DURING THE DAY TODAY AS A MORE UNSTABLE PROFILE COULD RESULT. A 12 TO 16 MB SURFACE GRADIENT IS FORECAST TO DEVELOP ACROSS EASTERN NEW MEXICO THIS MORNING. WITH 50 KT WINDS SHOWING UP ON KTCC AND WSMR WIND PROFILERS TONIGHT...ENOUGH EVIDENCE FOR TODAY/S WIND HIGHLIGHTS TO REMAIN IN PLACE. CONCERNED LINCOLN COUNTY MAY TO BE UPGRADED...AS THEY MAY EXPERIENCE THE BETTER CLEARING TODAY. AREAS OUR WEST MAY ALSO BLOW CLOSE TO WIND ADVISORY TODAY. ENOUGH LINGERING MOISTURE MAY EXIST TO TURN ANY REMAINING RAIN TO SNOW OVER MUCH OF THE W...AS WELL AS THE CENTRAL AND SOUTH CENTRAL MOUNTAINS...CENTRAL HIGH PLAINS AND NE HIGHLANDS TONIGHT ONCE THE COLDER AIR ARRIVES. AN EXTENSION OR EXPANSION OF SOME SORT OF WINTER WEATHER HIGHLIGHTS MAY NEED TO BE ISSUED FOR SOME OF THESE AREAS ON LATER SHIFTS. THE WINDS AND PRECIPITATION WILL DIMINISH SUNDAY WITH ANY LINGERING PRECIPITATION CONFINED TO THE CENTRAL AND WEST. THE REST OF THE WEEK IS NOW LOOKING AS IF IT WILL BE DRY...WITH NO STORMS ON THE HORIZON UNTIL NEXT WEEKEND. && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES ABOVE 7500 FEET...NMZ002-004. HIGH WIND WARNING UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ005>007-010>013-016>017-026. WIND ADVISORY UNTIL 6 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ001-008>009-014>015-018>021. && $$ 44 nm