AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 251 PM MDT THU OCT 19 2006 .SHORT TERM... (TONIGHT AND FRIDAY) CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING MODERATE NORTHWEST FLOW ALOFT ACROSS THE REGION WITH A BROAD UPPER TROUGH PERSISTING ACROSS THE INTERMOUNTAIN WEST. WATER VAPOR IMAGERY IMAGERY ALSO INDICATING AN EMBEDDED SHORT WAVE MOVING ACROSS THE NORTHERN HIGH PLAINS WITH ANOTHER EMBEDDED WAVE MOVING ONSHORE ACROSS THE PAC NW COAST ATTM. AT THE SFC...1-2MB 3HRLY PRESSURE FALLS BEING NOTED ACROSS THE I-25 CORRIDOR IN RESPONSE TO THE NORTHWEST FLOW ALOFT. FOR TONIGHT...MODERATE NORTHWEST FLOW CONTINUES ACROSS THE REGION TONIGHT AND SLOWLY INCREASES OVERNIGHT AS PAC NW SHORT WAVE CONTINUES TO MOVE INTO THE NORTHERN GREAT BASIN. WITH THE INCREASING FLOW ALOFT...WINDY CONDITIONS EXPECTED ACROSS THE HIGHER TERRAIN OVERNIGHT...AND WITH LEE TROUGHING PERSISTING ACROSS THE I-25 CORRIDOR...A DECENT GRADIENT SETS UP FOR GAP FLOWS ACROSS THE LOWER EASTERN SLOPES. WITH THAT IN MIND...HAVE WARMED UP LOWS ACROSS THE EASTERN SLOPES AND IMMEDIATE EASTERN PLAINS...THOUGH HAVE GONE AOB COLDEST GUIDANCE ACROSS THE EASTERN PLAINS TONIGHT...THINKING THAT WINDS WILL DECOUPLE ENOUGH THIS EVENING TO ALLOW TEMPS TO TANK THROUGH THE LATE NIGHT HOURS...ESPECIALLY ACROSS THE LOWER ARKANSAS RIVER VALLEY. MODEL CROSS SECTIONS CONTINUE TO INDICATE THIN LAYER OF MOISTURE PERSISTING OVER THE CENTRAL MTS WITH THE NORTHWEST FLOW...THOUGH WITH POOR LAPSE RATES...NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS OVERNIGHT. FRIDAY...WESTERLY FLOW INCREASES ALOFT AS EMBEDDED SHORT WAVE CONTINUES TO MOVE ACROSS THE GREAT BASIN AND INTO NORTHWESTERN COLORADO BY THE LATE AFTERNOON. CROSS SECTIONS INDICATING MOISTURE AND LAPSE RATES INCREASING AHEAD OF THE SYSTEM...WITH SNOW MODEL YIELDING 1 TO 3 INCHES ACROSS THE CENTRAL MTS...THOUGH WITH SOME QG IMPLIED ASCENT HAVE GONE WITH UP TO 4 INCHES ACROSS ZONES 58 AND 60 WITH LATER SHIFTS MAY BE NEEDING TO HOIST AN ADVISORY FOR LATE FRIDAY AFTERNOON AND NIGHT. PREFRONTAL TROUGH SETS UP ACROSS THE FAR EASTERN PLAINS THROUGH THE AFTERNOON...ALLOWING FOR BREEZY WESTERLY WINDS TO MIX DOWN ACROSS SOUTHEAST COLORADO...WITH DOWNSLOPE HELPING TEMPS TO CLIMB INTO THE 60S ACROSS THE PLAINS. -MW .LONG TERM... (FRIDAY NIGHT THROUGH THURSDAY) ...FCST CONCERNS THIS PD CONTINUE TO BE SAT WX SYSTEM AND A NEW SYSTEM FOR LATER IN THE WEEK... MAIN CONCERN CONTINUES TO BE WX SYSTEM FOR FRI NITE INTO SATURDAY. CURRENT WAT VAP IMGY CURRENTLY SHOWING THIS SYSTEM UP ACROSS S ALASKA AND INTO NW CANADA. SYSTEM LOOKS QUITE IMPRESSIVE IN THE IMGY. RAW MODEL DATA DOES NOT APPEARS ALL THAT IMPRESSIVE AS SYSTEM CROSSES OUR AREA BUT BELIEVE MODEL MAY BE A BIT UNDERDONE GIVEN CURRENT SAT PIX REPRESENTATION AND MODEL OUTPUT STATISTICS DATA. LATEST FCST BRINGS FRONT INTO AREA LATE THU AFTERNOON OR EARLY FRIDAY EVENING. GUSTY N WINDS SHOULD COME ALONG WITH THE FROPA. RAW GRIDDED DATA SHOWS SYSTEM RATHER DRY BUT BELIEVE THIS IS UNDERDONE AND HAVE CONTINUED CURRENT TREND IN BRING CLOUDS INTO REGION FRI EVENING. AS FOR POPS...GIVEN LAPSE RATES AND FORCING...BELIEVE THERE WILL BE SOME POTENTIAL FOR SOME STEADY WIND DRIVEN SNOW ACROSS THE C MTNS FRI EVE INTO SAT. AS MENTIONED ABOVE IS SHORT TERM DISCUSSION...HILITES WILL LIKELY BE NECESSARY FOR THIS REGION. ON PLAINS...BEST CHANCE OF PRECIP WILL BE ALONG S FACING SLOPES OF S MTNS AND ALONG THE I-25 CORRIDOR FRI EVE...AND THEN DOWN TOWARDS THE S SANGRES/RATON MESA REGION ON SATURDAY. I AM QUITE CONFIDENT THAT WE WILL ONCE AGAIN SEE COLDER TEMPS COME IN FRIDAY NITE AND INTO SAT. TEMPS SAT WILL LIKELY BE 20F COOLER THAN FRIDAY. BY SUNDAY...SHOULD SEE A BIT MORE SUN ON THIS DAY...BUT TEMPS WILL STILL BE ON THE COOL SIDE. FOR NEXT WEEK...NICE WX WITH TEMPS WARMING INTO THE 60S TO LOWER 70S WITH DRY WX. BY LATE IN THE WEEK...COUPLE RUNS OF THE GFS AND EURO MODELS ARE NOW SHOWING A RATHER IMPRESSIVE TROUGH DEVELOPING OVER THE INTERMOUNTAIN WEST. IF THE MODELS ARE A PERFECT PROG...THEN THIS WILL BE A PRETTY GOOD STORM...HOWEVER...FOR NOW...THE ONLY CHANGES I MADE TO THE LONG RANGE PERIOD WAS TO INTRODUCE A SLIGHT CHANCE OF PRECIP ACROSS THE REGION WED NITE INTO THU. \/HODANISH && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/34 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 848 AM MDT THU OCT 19 2006 .UPDATE...AN UPDATE WILL BE ISSUED SHORTLY TO REMOVE THE FREEZE WARNING HEADLINE AS WELL AS INCREASE CLOUD COVER BASED ON LATEST SATELLITE TRENDS AS THE EXIT REGION OF H3 90KT JET DIVES SOUTHEAST ACROSS THE AREA. THE CLOUDS MAY LIMIT HEATING EVEN WITH LOW LEVEL DOWNSLOPE FLOW. INCREASING SUBSIDENCE LATE IN THE PERIOD SUPPORTS SOME BREAKS IN THE CLOUDS SO ONLY ADJUSTED MAXIMUM TEMPERATURES DOWN SLIGHTLY WHERE HIGHEST CONFIDENCE WAS. EXPECT HIGHS TO RANGE FROM THE MID 50S WEST/NORTHWEST TO AROUND 60/LOWER 60S SOUTHEAST. MCGUIRE && .PREV DISCUSSION... (ISSUED 245 AM MDT THU OCT 19 2006) DISCUSSION...A FREEZE WARNING CONTINUES THROUGH THIS MORNING. FORECAST CONCERNS INCLUDE THE AMOUNT OF WARMUP TODAY AND FRIDAY ALONG WITH TEMPERATURES AND THE RESULTING PRECIPITATION PHASE WITH THE NEXT SYSTEM DUE THROUGH THE AREA FRIDAY NIGHT AND EARLY SATURDAY. SKIES REMAIN CLEAR WITH DEWPOINTS IN THE MID TO UPPER 20S EARLY THIS MORNING WITH LIGHT SOUTHWEST WINDS RAISING TEMPERATURES SLIGHTLY ACROSS PORTIONS OF THE TRI-STATE REGION. HOWEVER...TEMPERATURES ACROSS THE FORECAST AREA HAVE ALREADY...OR ARE EXPECTED TO RETURN TO THE UPPER 20S AS WINDS SLACKEN AROUND SUNRISE. MODELS HAVE BEEN REASONABLY AGREEABLE AND CONSISTENT OVER THE PAST COUPLE OF RUNS. NORTHWEST FLOW PERSISTS THROUGH THE WEEKEND WITH SHORT WAVE RIDGING MOVING FROM THE ROCKIES TO THE HIGH PLAINS DURING THE FIRST HALF OF NEXT WEEK. HAVE USED MORE OF A GFS SOLUTION WITH A BLEND OF THE RUC WIND FIELDS AND DEWPOINTS IN THE SHORT TERM. THE GOING FORECAST WAS IN PRETTY GOOD SHAPE AND ONLY MADE MINOR CHANGES OVERALL. THE BIGGEST CHANGE WAS TO MODIFY TIMING AND COVERAGE AREAS OF THE DIFFERENT PRECIPITATION TYPES FRIDAY NIGHT AND EARLY SATURDAY AS NEAR SURFACE TEMPERATURES APPROACH AND JUST MANAGE TO REACH FREEZING IN THE NORTHWEST SECTIONS. UP TO A TENTH OF AN INCH OF MOISTURE IS EXPECTED ACROSS THE ENTIRE FORECAST AREA WITH ONLY A COUPLE TENTHS OF AN INCH OR LESS OF SNOWFALL EXPECTED OVER THE WESTERN PORTIONS OF THE COLORADO COUNTIES. HAVE KEPT THE REMAINDER OF THE FORECAST DRY WITH A GRADUAL WARMING TREND FROM THE LATTER PART OF THE WEEKEND THROUGH THE MIDDLE OF NEXT WEEK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LOUISVILLE KY 931 PM EDT THU OCT 19 2006 .UPDATE... SECONDARY AREA OF RAIN PRECEDED BY SCT SHRA MOVING INTO THE LMK CWA AS OF 1Z. EXPECTING THIS ACTIVITY TO MOVE THROUGH CWA BETWEEN NOW AND ABOUT 1AM EDT...THEN CUTOFF QUICKLY GIVEN DISTINCT BACK EDGE TO PRECIP SEEN ON PAH RADAR AS UPPER LEVELS DRY OUT. WILL CONTINUE 100% POPS ASSOC WITH THIS ACTIVITY...THEN TAPER OFF QUICKLY FROM WEST TO EAST. UPSTREAM OBS INDICATING RAINFALL RATES BETWEEN ONE TENTH AND ONE QUARTER INCH PER HOUR. ITS LIKELY WE COULD SEE SOME BRIGHT BANDING ON RADAR (AND OVERESTIMATES OF PRECIP) WITH SIGNIFICANTLY LOWER FRZ LEVELS SPREADING INTO THE DISTRICT ASSOC WITH UPPER TROF AXIS. IN FACT...RUC IS ANALYZING A TIGHT FRZ LEVEL GRADIENT FROM NEAR IND TO SRN IL AS OF 2Z. BUT EVEN WITH ONLY MODEST RAIN AMOUNTS GIVEN THE VERY WET SOILS...WE COULD SEE SOME RENEWED PONDING WATER AND PERHAPS SOME MINOR FLOODING IN LOW SPOTS...WHICH WE'LL LIKELY HANDLE WITH AN SPS IF THE NEED ARISES. CIGS INCREASE INTO THE MVFR RANGE NEAR AND AFTER THIS RAIN BAND...AND EXPECT THIS TO BE THE CASE AS IT MOVES THROUGH THE CWA. TEMPS ARE ALREADY INTO THE LOWER 40S AT HNB...WITH EVEN SOME UPPER 30S IN SE IL. MAY LOWER FCST MINS A DEGREE OR SO IN OUR SRN IND COUNTIES TO REFLECT THIS...LEAVING LOW 40S IN THE KY COUNTIES. UPDATED FCST OUT BY 10 PM EDT. CS && .PREV DISCUSSION... (ISSUED 727 PM EDT THU OCT 19 2006) UPDATE... SFC COLD FRONT NOW EAST OF THE LMK CWA...WITH LOW PRES ORGANIZING ALONG FRONT OVER ALABAMA AS OF 23Z. FIRST AREA OF RAIN NOW OVER THE BLUEGRASS IS EXPECTED TO DEPART THE CWA WITHIN THE NEXT HOUR. EVEN THROUGH RAINFALL AMOUNTS HAVE NOT BEEN EXCESSIVELY HIGH (1-1.5 INCHES)...THE VERY WET GROUND MEANS ALL THIS HAS BEEN QUICKLY CONVERTED TO RUNOFF...SO WE HAVE A FLOOD ADVISORY OUT UNTIL 9 PM FOR PARTS OF THE BLUEGRASS WHERE HEAVIEST RAINS HAVE FALLEN. ONLY EXPECTING MINOR FLOODING OF NORMALLY FLOOD PRONE SPOTS. SECOND AREA OF RAIN...IMMEDIATELY AHEAD OF 500MB SHORTWAVE... TRANSLATING EASTWARD ACROSS SRN IL/WRN KY/SW IN...AND IS EXPECTED TO AFFECT THE CWA DURING THE MID/LATE EVENING HOURS. ONGOING FORECAST IS IN GOOD SHAPE...THOUGH WILL UPDATE TO REMOVE THUNDER IN ERN ZONES. TAF WISE...LOW CIGS ARE CONTINUING OVER THE REGION...THOUGH CURIOUSLY ENOUGH CIGS ARE HIGHER OUT WEST WHERE 2ND RAIN AREA IS. HOWEVER MODEL RH FIELDS AND MOS ARE INDICATING IFR/LIFR CIGS CONTINUING THROUGH THE PRE-DAWN HOURS. WILL KEEP LOW CIGS IN TAFS THROUGH BALANCE OF THE EVENING...BUT AS 2ND AREA OF SHOWERS PASSES WILL ALLOW FOR GRADUALLY INCREASING CIGS. HIGH UNCERTAINTY HERE...SO FREQ UPDATES TO TAFS ARE LIKELY AS CONDITIONS EVOLVE. CS PREV DISCUSSION... (ISSUED 230 PM EDT THU OCT 19 2006) IN THE SHORT TERM (TONIGHT AND FRIDAY)... WATER VAPOR IMAGERY SHOWS A BROAD PROGRESSIVE TROUGH CENTERED OVER THE SOUTHERN PLAINS...WITH AN UPPER AIR DISTURBANCE ROTATING THROUGH THE BASE OF THE TROUGH CURRENTLY LOCATED ACROSS OKLAHOMA. AMPLE MID AND HIGH LEVEL MOISTURE IS STREAMING ACROSS THE LOWER OHIO VALLEY ASSOCIATED WITH BROAD SOUTHWEST FLOW. THIS DISTURBANCE WILL RAPIDLY TRANSLATE EASTWARD ALONG THE OHIO RIVER...MOVING INTO OHIO BY MIDDAY FRIDAY. AT THE SURFACE...A SHARP COLD FRONT WILL SLIDE SOUTHEAST...EXITING CENTRAL KENTUCKY LATER THIS AFTERNOON. WEAK LOW PRESSURE WILL MOVE ALONG THIS FRONT THIS EVENING ACROSS THE TENNESSEE VALLEY AND STRENGTHEN TOMORROW AS IT MOVES INTO NEW ENGLAND. SHOWERS AND EVEN SOME ELEVATED THUNDERSTORMS WILL INCREASE THROUGH THE EARLY EVENING HOURS AS JET STREAM MOVES OVERHEAD AND UPPER DISTURBANCE MOVES THROUGH. COVERAGE WILL BE WIDESPREAD WITH MOST AREAS RECEIVING RAINFALL AMOUNTS OF A HALF INCH OR MORE. BOTH THE GFS AND THE NAM BRING THE BEST DYNAMICS THROUGH CENTRAL KENTUCKY AROUND MID EVENING. BOTH HINT AT PERHAPS TWO AREAS OF ENHANCE RAINFALL. THE FIRST WILL BE ASSOCIATED WITH GREATER INSTABILITY AND PROXIMITY TO SURFACE COLD FRONT ACROSS THE TENNESSEE VALLEY. THE SECOND IS ASSOCIATED WITH DYNAMICS ASSOCIATED WITH FAVORABLE JET STREAM POSITION AND WILL MOVE MAINLY ACROSS CENTRAL AND SOUTHERN KENTUCKY DURING THE EVENING HOURS. SHOWERS WILL QUICKLY END FROM WEST TO EAST OVERNIGHT AS SYSTEM RAPIDLY MOVES AWAY. BASE OF THE UPPER TROUGH WILL CROSS AREA EARLY TOMORROW AND WITH IT...DEEP LAYER MOISTURE. CLEARING MAY BE SLOW TO ARRIVE TOMORROW. FORECAST SOUNDINGS SHOW A SATURATED MOIST LAYER BELOW 925MB TRAPPED BELOW A STRENGTHENING INVERSION...WITH DIMINISHING BOUNDARY LAYER WINDS BY THE EVENING. FEEL THAT BEST CHANCE OF AFTERNOON CLEARING TOMORROW WILL BE WEST OF INTERSTATE 65. NORTH WINDS WILL CONTINUE TO ADVECT IN COLDER AIR OVERNIGHT AND EXPECT CHILLY TEMPS IN THE LOWER 40S BY MORNING. AS HIGH PRESSURE BUILDS IN TOWARDS TOMORROW EVENING...WINDS WILL BECOME LIGHT. JSD LONG TERM (FRIDAY NIGHT THROUGH THURSDAY) FRIDAY NIGHT THROUGH MONDAY... UPPER LEVEL VORTEX WILL SPIN NORTH OF THE GREAT LAKES FOR A FEW DAYS .PRODUCING GENERALLY BELOW AVERAGE TEMPERATURES INTO THE BEGINNING OF NEXT WEEK. AFTER SHORT WAVE DEPARTS EAST LATE FRIDAY...RIDGE IS DEPICTED ALONG PACIFIC COAST WITH MORE OR LESS ZONAL FLOW FROM THE ROCKIES TO THE ATLANTIC COAST. A SHORT WAVE ROTATING AROUND THE UPPER VORTEX FROM THE NORTHERN ROCKIES WILL DROP SOUTHEAST INTO THE CENTRAL PLAINS SATURDAY...THEN EAST INTO THE OHIO VALLEY. THIS WILL RESULT IN A DRY DAY WITH SEASONABLE TEMPERATURES...WITH SHOWERS MOVING IN FOR SATURDAY INTO SUNDAY. INTENSIFYING LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL MOVE NORTHEAST...BUT WILL LEAVE A MOSTLY CLOUDY BUT DRY DAY MONDAY...THOUGH WITH A COOL NORTHWEST BREEZE. .MONDAY NIGHT THROUGH THURSDAY... UPPER VORTEX CHANNELING CANADIAN AIR INTO THE EASTERN TWO THIRDS OF THE COUNTRY WILL MOVE EAST DURING THIS PERIOD. THIS WILL PROVIDE A BREAK FROM THE UNSETTLED WEATHER PATTERN OF THE PAST 10 DAYS. SURFACE HIGH PRESSURE WILL PREVAIL...RESULTING IN COOL BUT MAINLY DRY CONDITIONS THROUGH THURSDAY. THE GFS LATEST RUN WAS LESS AMPLIFIED THAN THE PRIOR RUN...WHERE ANOTHER FRONT AND CHANCE OF SHOWERS WAS SUGGESTED ABOUT NEXT THURSDAY. LATER RUNS WILL GIVE GUIDANCE ON WHETHER SHOWERS NEED MENTIONING FOR THURSDAY OR NOT. -REITMEYER && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 945 PM EDT THU OCT 19 2006 .UPDATE... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG MOVING INTO THE UPR GRT LKS. LOCAL 00Z RAOBS/TAMDAR SDNGS SHOW SHARP INVRN BTWN H85-H875...WITH VERY DRY AIR NOTED ABV THE INVRN. SUB INVRN LYR IS RATHER DRY AS WELL BLO SHALLOW MOIST LYR NR INVRN BASE. SC OVC UNDER INVRN BASE IS GENERALLY HI MVFR/LO VFR HGT. LOWEST TEMP WITHIN MIXED LYR AT INVRN BASE ABOUT -7C TO -8C. DIURNAL --SHRASN HAVE DSPTD WITH DNVA/H85-5 QVECTOR DVGC/H7 SUBSIDENCE AND ARRIVAL OF MORE ACYC FLOW ASSOCIATED WITH WEAK SFC AXIS OF HI PRES UNDER SHRTWV RDG. SOME HIER CLD STREAMING INTO THE UPR LKS AHEAD OF SHRTWV NOW MOVING INTO SW MN. ALTHOUGH SOME ISENTROPIC LIFT ON THE 280-300K SFCS/H85-5 QVECTOR CNVGC IN ADVANCE OF THIS SYS FCST TO SPREAD INTO THE WRN CWA OVERNGT...MID LVLS FCST TO REMAIN PROHIBITIVELY DRY. SINCE SN GROWTH MICROPHYSICS POOR (MIXED LYR SVRL DEGREES WARMER THAN -10C) HAVE REMOVED MENTION OF PCPN EXCEPT FOR SOME LINGERING ISOLD -SHRA OVER ERN LK SUP CLOSER TO LINGERING THERMAL TROF/BIT HIER INVRN BASE THAT MIGHT HAVE A CHC TO TAPE COLDER AIR. THESE -SHRA WL TEND TO DIMINISH LATE WITH ARRIVAL OF MORE ACYC FLOW AND BACKING LLVL FLOW. EVEN THOUGH SOME UVV PSBL LATE WITH THE ARRIVAL OF QVECTOR CNVGC... ACCOMPANYING WAD WL MAINTAIN SHARP INVRN AND SC OVC IN PLACE NOW. GOING FCST LO TEMPS APPEAR IN GOOD SHAPE WITH RELATIVELY SMALL DIURNAL TEMP DCRS EXPECTED UNDER OVC. KC .PREVIOUS DISCUSSION (ISSUED AT 423 PM EDT)... UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE ALONG THE WEST COAST AND ACROSS FLORIDA WITH BROAD TROUGHING ACROSS THE REST OF THE COUNTRY AND A CLOSED 500 MB LOW OVER NORTHERN ONTARIO. THERE IS A STRONG SHORTWAVE DIGGING SE ACROSS B.C. WITH STRONG DARKENING NOTED ON WATER VAPOR AND ALSO A BAROCLINIC LEAF ON WATER VAPOR ACROSS THE WRN CANADIAN PROVINCES AND ACROSS WA/ID. SEVERAL SHORTWAVES ARE NOTED IN THE BROAD TROUGH WITH ONE OVER THE WRN DAKOTAS AND ONE ACROSS CENTRAL IA INTO THE LOWER PENINSULA OF MICHIGAN. THE B.C. SHORTWAVE WILL CONTINUE TO DIG SE AND WILL PASS TO THE SOUTH OF THE AREA SAT AND SUN WITH THE CLOSED 500 MB LOW OVER ONTARIO SLOWLY ROTATING TO THE SOUTH THROUGH THE PERIOD WITH WEAK SHORTWAVES EVERY SO OFTEN ROTATING AROUND IT. NAM IS BRINGING THE STORM SYSTEM FURTHER WEST FOR THIS WEEKEND THAN IN PREVIOUS RUNS AND THIS IS A DEPARTURE FROM PREVIOUS MODEL RUNS WHICH HAD THE SYSTEM OVER THE LOWER GREAT LAKES. GFS CONTINUES TO SHOW THINGS FURTHER EAST AND HAS SOLUTION CONTINUITY ON ITS SIDE AND WILL GO WITH ITS SOLUTION FOR FRI AND BEYOND. NAM SHOWING THE DAKOTAS SHORTWAVE BRINGING IN SOME 850-500 MB Q-VECTOR CONVERGENCE TONIGHT WITH THIS REMAINING OVER THE CWA ON FRI. NAM ALSO SHOWING SOME ISENTROPIC LIFT AND MOISTURE COMING BELOW 850 MB TONIGHT ACROSS THE CWA ON I280K SURFACE. NAM DOES BRING SOME ISENTROPIC LIFT AND MOISTURE ON I285K-I290K SURFACES ACROSS THE CWA ON FRI WITH A NARROW RIBBON OF MOISTURE BELOW 700 MB. GFS SHOWS ABOUT THE SAME THING WITH LIFT AND MOISTURE BELOW 850 MB ON THE ISENTROPIC SURFACE OF I280K TONIGHT AND LIFT AND MOISTURE BELOW 700 MB ON I290K SURFACE ON FRI. ENOUGH OF A SIGNAL IS THERE TO PUT IN SOME SPRINKLES/FLURRIES FOR MOST OF THE NIGHT WITH LAKE EFFECT SHOWERS GOING ON INTO THE EVENING BEFORE WINDS BECOME LIGHT ENOUGH TO GO WITH SPRINKLES/FLURRIES THEN EAST OF MARQUETTE AND FLURRIES ELSEWHERE. FOR FRI...WENT WITH LOW CHANCE POPS WITH THE DAKOTAS SHORTWAVE PASSING ACROSS THE AREA AND SOME MID LEVEL MOISTURE AND ISENTROPIC LIFT COMES ACROSS THE AREA. LAKE EFFECT THEN KICKS IN FOR FRI NIGHT THROUGH SUN. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. WENT WITH THE WARMEST GUIDANCE FOR LOW TEMPERATURES AND CLOSE TO THE COLDEST GUIDANCE FOR HIGHS WITH THE SMALLEST DIURNAL TEMPERATURE RANGE BECAUSE CLOUD COVER WILL REMAIN FOR MOST OF THE PERIOD. WENT MOSTLY WITH THE ADJMEN FOR TEMPERATURES. IN THE EXTENDED...500 MB PATTERN CONSISTS OF A TROUGH ACROSS THE CENTRAL AND EASTERN U.S. WITH RIDGING ACROSS THE WESTERN U.S. 00Z MON. TROUGH REMAINS INTO MON WITH A CLOSED LOW TO THE EAST OF THE AREA. BY TUE...TROUGH AXIS IS EAST AND UPPER LEVEL RIDGING IS ACROSS THE NORTHERN PLAINS 00Z WED WITH RIDGING PUSHING INTO THE UPPER GREAT LAKES 00Z THU. 06Z GFS AND ECWMF SHOW THIS SOLUTION WHILE THE 00Z GFS AND CANADIAN SHOW TROUGHING REMAINING IN THE AREA THROUGH THE PERIOD. MODEL CONTINUITY WOULD ARGUE WITH TROUGHING REMAINING IN THE REGION WITH RIDGING BEING A NEW SOLUTION TODAY COMPARED TO YESTERDAY. WILL STICK WITH 00Z GFS SOLUTION AND KEEP TROUGHING IN THE AREA WHICH MEANS LAKE EFFECT PCPN WILL CONTINUE INTO WED NIGHT AND THEN WITH UPPER LEVEL AND LOW LEVEL RIDGING IN THE AREA...LAKE EFFECT ENDS FOR THU AND WILL GO DRY FOR NOW ON THAT DAY. WITH TROUGHING IN THE AREA...TEMPERATURES LOOK TO STAY BELOW NORMAL. WENT CLOSE TO ADJMXR FOR LOWS AND HIGHS WHICH SEEMED REASONABLE BASED ON BELOW NORMAL TEMPERATURES. ALSO WENT WITH RAIN/SNOW MIX DURING THE DAY AND SNOW AT NIGHT BASED ON TEMPERATURES. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING EXTENDED FORECAST. MICHELS && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1020 AM EDT THU OCT 19 2006 .UPDATE... OVERALL...GOING FCST IN GOOD SHAPE. ADDED SCT SNOW SHOWERS INTO GRIDS IN FAR W CWA VCNTY OF KIWD. VSBY ON AWOS SINCE 1235Z SHOWING AROUND 3SM WITH REPORT OF SNOW ATTM FM THAT AREA. WIND AT KIWD IS MORE SW WHILE WINDS OVR W LK SUPERIOR SHOW MORE NW DIRECTION. CONVERGENCE MAY BE ENHANCING THE SNOW SOMEWHAT. OTHERWISE... SHORTWAVE TROF IS IN PROCESS OF CROSSING UPR MI. BEST CHANCE FOR MEASURABLE PCPN WILL CONTINUE OVR E SECTIONS AS NW WINDS FLOW OVER LK SUPERIOR. MORNING KSAW TAMDAR AND RAOB FM GRB SHOWED MOIST LAYER TO AROUND 800MB WITH H85 TEMPS NEAR -5C. PCPN SHOULD PERSIST AS H85 TEMPS SLIGHTLY FALL THIS AFTN AND MOISTURE IS SLOW TO DEPART. DID KEEP IDEA OF ENDING PCPN OVR W HALF THIS AFTN ONCE SHORTWAVE TROF PASSES BY AND THERE IS HINT OF SOME SHORTWAVE RIDGING UPSTREAM OVR MN. PUBLISHED GRIDS OUT AND TEXT ZFPMQT UPDATE WILL BE OUT SHORTLY. && .DISCUSSION... MAIN FCST ISSUE FOR THE NEXT FEW DAYS IS PCPN POTENTIAL WHICH WILL FREQUENTLY REVOLVE AROUND LAKE EFFECT PCPN. WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A TROF DOMINATING CNTRL CANADA INTO THE CNTRL/WRN CONUS WITH INDICATIONS OF A VORTEX REDEVELOPING OVER NRN MANITOBA/NW ONTARIO. SHORTWAVE LIFTING NE WITHIN THE POSITIVELY TILTED TROF OVER THE CNTRL CONUS INTO THE GREAT LAKES BROUGHT SOME -RA TO MAINLY THE SE 2/3RDS OF THE FCST AREA LAST EVENING. TO THE W...A SHORTWAVE IS DIVING SE ACROSS ALBERTA/SASKATCHEWAN/MT. THIS WILL BE A FEATURE OF INTEREST FRI. FARTHER TO THE NW...AN IMPRESSIVE LOOKING SHORTWAVE OVER THE NE GULF OF ALASKA WAS APPROACHING NRN BRITISH COLUMBIA. EVOLUTION OF THIS SYSTEM WILL BE A FCST ISSUE LATE IN THE WEEKEND AS IT MOVES THRU THE LONGWAVE TROF POSITION FROM HUDSON BAY S ACROSS THE CNTRL CONUS. LAKE EFFECT PCPN HAS BEEN TAKING SHAPE OVERNIGHT...MAINLY OVER ERN LAKE SUPERIOR...AS AIRMASS CONTINUES TO COOL WITH CAA FROM THE NW. 00Z KINL/CWPL SOUNDINGS SHOWED 850MB TEMPS OF -7C...SUFFICIENT FOR LAKE EFFECT PCPN WITH LAKE SUPERIOR SFC WATER TEMPS GENERALLY 8-9C. KINL SOUNDING INDICATED INVERSION BASE AT 5.4KFT WHILE IT WAS BASED AT 4.6KFT AT CWPL. AIRMASS BLO INVERSION WAS MOIST...FURTHER SUPPORTING LAKE EFFECT PCPN DEVELOPMENT. EXPECT LAKE EFFECT -SHRA/-SHSN/SPRINKLES/FLURRIES TO CONTINUE THIS MORNING FOR NW FLOW AFFECTED AREAS DUE TO FAVORABLE INSTABILITY. PCPN WILL BE FURTHER SUPPORTED BY MOIST SUB INVERSION PROFILE ALREADY PRESENT IN THE AIRMASS BEFORE PASSING OVER THE LAKE. HOWEVER...PCPN WILL REMAIN QUITE LIGHT DUE TO POOR SNOW GROWTH MICROPHYSICS AS TEMPS WITHIN MOIST LAYER ARE GENERALLY ABOVE -10C. DID NOT MENTION ANY SNOW OVER THE ERN PART OF THE FCST AREA AS FCST SOUNDINGS SHOW SFC-BASED ABOVE FREEZING LAYER WELL OVER 1KFT DEEP. THIS AFTN...FLOW BECOMES INCREASINGLY ANTICYCLONIC WITH SFC RIDGE BUILDING INTO THE UPPER GREAT LAKES REGION. INCREASINGLY ANTICYCLONIC FLOW COMBINED WITH DAYTIME HEATING DISRUPTING HEAT/MOISTURE FLUXES OFF THE LAKE AND ADVECTION OF DRIER AIR FROM THE W PER FCST SOUNDINGS WILL SPELL THE DEMISE OF LAKE EFFECT PCPN FROM W TO E LATE MORNING THRU MID AFTN. AWAY FROM LAKE EFFECT PCPN...MIGHT BE A FEW SPRINKLES/FLURRIES EARLY THIS MORNING...BUT OTHERWISE ANTICIPATE SOLID CLOUD DECK WILL BREAK UP THROUGH THE DAY WITH ANTICYCLONIC FLOW AND ADVECTION OF DRIER AIR. ANY LINGERING STRATOCU SHOULD DEPART EARLY THIS EVENING IN CONJUNCTION WITH LOW-LEVEL RIDGE AXIS...BUT AT THE SAME TIME THERE WILL PROBABLY BE SOME INCREASE IN HIGH CLOUDS ASSOCIATED WITH SHORTWAVE NOW OVER THE NRN ROCKIES WHICH WILL BE HEADING TO THE MID MISSISSIPPI VALLEY. STILL...THERE WILL BE A WINDOW OF OPPORTUNITY FOR GOOD RADIATIONAL COOLING TONIGHT WITH LIGHT/CALM WINDS. WILL THUS FAVOR LOW END OF MOS GUIDANCE TONIGHT. ALTHOUGH FORCING WITH SHORTWAVE REACHING THE MISSISSIPPI VALLEY TONIGHT WILL PASS WELL S AND SE OF HERE FRI...MODELS STILL INDICATE A WEAKER SHORTWAVE TRACKING INTO THE UPPER LAKES WITH A WEAK SFC LOW REFLECTION. IN THIS REGARD...THE GFS HAS COME AROUND TOWARD THE NAM SOLUTION. LOW-LEVEL CONVERGENCE NEAR LOW AND WEAK MOIST ISENTROPIC ASCENT VIEWED ON 290K SFC (AROUND 700MB) SHOULD BE SUFFICIENT TO WARRANT LOW END CHC POPS FOR -SHRA SPREADING W TO E FRI AFTN/EVENING. AS SFC LOW TRACKS E FRI NIGHT...CAA GETS UNDERWAY WITH 850MB TEMPS DROPPING TO AROUND -8C PER PREFERRED COOLER GFS SOLUTION. SO...EXPECT LIGHT LAKE EFFECT -SHRA/-SHSN TO DEVELOP OVER THE W DURING THE NIGHT. LAKE EFFECT PCPN SHOULD THEN DEVELOP INTO THE ERN FCST AREA SAT AS CAA CONTINUES AROUND SOUTHERN SIDE OF VORTEX WHICH WILL BE WELL ESTABLISHED AGAIN OVER ONTARIO BY THAT TIME (850MB TEMPS SHOULD BE AROUND -8C ACROSS MOST OF LAKE SUPERIOR BY SAT AFTN). AWAY FROM LAKE EFFECT PCPN...HAVE KEPT GOING CHC POPS AS DEEPER MOISTURE ROTATES INTO THE UPPER LAKES. SHORTWAVE CURRENTLY APPROACHING NRN BRITISH COLUMBIA WILL REACH THE SRN PLAINS SAT AND WILL MOVE NE INTO THE GREAT LAKES SUN. MODEL CONSENSUS CONTINUES TO INDICATE THIS SYSTEM WILL PASS SE OF THE FCST AREA AND HAVE LITTLE IMPACT ON SENSIBLE WEATHER HERE. EVEN SO...IT WILL REMAIN UNSETTLED ACROSS THE UPPER LAKES WITH MID/UPPER TROF/DEEP CYCLONIC FLOW DOMINATING THE AREA. LAKE EFFECT PCPN SHOULD BECOME FAIRLY WIDESPREAD NEAR LAKE SUPERIOR EVEN THOUGH INSTABILITY WILL NOT BE SIGNIFICANT (850MB TEMPS -7/-8C). && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA DISCUSSION...ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 721 PM EDT THU OCT 19 2006 .AVIATION... LINE OF THUNDERSTORMS PROGRESSING ACROSS THE REGION THIS EVENING WILL AFFECT TERMINALS BETWEEN 00Z AND 03Z. TEMPO VIS OF 1SM TO 3SM IS EXPECTED IN DOWNPOURS. RAIN WILL CONTINUE OFF AND ON THROUGH THE OVERNIGHT HOURS WITH WIDESPREAD MVFR CONDITIONS. UPPER ELEVATION LOCATIONS (BGM) AND LAKE SHORE TERMINALS (ITH) WILL EXPERIENCE IFR CONDITIONS TOWARD EARLY MORNING. DJP && .PREV DISCUSSION... /ISSUED 624 PM EDT THU OCT 19 2006/ SHORT TERM /REST OF TONIGHT/... UPDATED ZONES/GRIDS TO REMOVE AFTERNOON WORDING AND INCLUDE CHC OF EVENING TSRA ACROSS MUCH OF CWA THIS EVENING. RUC MODEL SOUNDINGS INDICATE STEEP MID LEVEL LAPSE RATES WILL CONTINUE UNTIL LATE EVENING. RRM PREV DISCUSSION... /ISSUED 413 PM EDT THU OCT 19 2006/ SHORT TERM /TONIGHT - SUNDAY/... ACTIVE WEATHER CONTINUES IN THE SHORT TERM. A STRONG COLD FRONT IN FAR WRN NY AND PA WILL SLOWLY MOVE EAST TONIGHT. AHEAD OF THE FRONT IS A LINE OF SHOWERS AND THUNDERSTORMS IN THE UNSTABLE AIR. SKIES PARTIALLY CLEARED WITH TEMPS RISING TO NEAR 70. LIS HAVE GONE NEGATIVE. LARGER AREA OF RAIN IN OHIO VALLEY WILL MOVE NE AHEAD OF A DEVELOPING AND INTENSIFYING LOW IN THE SE US. RAIN TO GET HERE THIS EVENING AND CONTIUE INTO FRIDAY MORNING. THIS LONG PERIOD OF RAIN WILL DROP OVER AN INCH EVERYWHERE WITH A STRIP CLOSE TO 2 INCHES FROM SW TO NE ELM TO UCA. THIS STRIP COULD SHIFT SOME DEPENDING ON WHERE THE SFC LOW TRACKS. FOR NOW THE TRACK OF THE LOW WILL BE OUR SE CWA FRI MORNING. MOST MODELS HAVE SIMILAR TRACKS. FOR ENDING TIME GFS FASTEST MIDDAY WITH NAM IN THE AFTN. THIS AMOUNT OF RAIN ONLY EXPECTED TO RAISE THE MOHAWK AT UTICA TO OVER FLOOD STAGE. THE RIVER ALREADY RUNNING HIGH WITH DELATA DAM FULL. OTHER STREAMS AND RIVERS WILL EXPERIENCE RISES BUT ARE NOT EXPECTED TO FLOOD. WITH THE LOW DEEPENING OVER NEW ENGLAND FRI PM...WINDS WILL PICK UP ESPECIALLY IN THE E. STILL BELOW ADVISORY CRITERIA BUT THIS WILL BRING IN THE COLD AIR FASTER. FRI NGT SOME SHOWERS POSSIBLE WHICH COULD CHANGE TO SNOW. POPS ARE AT 20 PERCENT WITH MARGINAL LAKE INSTABILITY. THIS WILL BE SHORT SHOT OF COLD AIR WITH WAA ON SATURDAY AHEAD OF THE NEXT SYSTEM. SFC HIGH BUILDS WITH WEAK UL RIDGING. FOR SUNDAY DIFFERENCES BETWEEN THE MODELS ON TIMING OF PRECIP. FOR NOW WENT WITH CHC POPS EVERYWHERE. THE NEXT STRONG COLD FRONT WILL CROSS THE CWA SUNDAY NIGHT. GFS BRINGS IN RAIN EARLY SUNDAY WITH THE NAM HOLDING OFF UNTIL AFTN. TAC AVIATION /191800Z - 201800Z/... CIGS ARE VARYING FROM 030-035 OVER THE VALLEYS TO 015-020 OVER THE MOUNTAINS. AREA OF MVFR CIGS AND SHOWERS WITH ISOLD TSTMS WILL MOVE ACROSS THE AREA BETWEEN 18Z AND 00Z. THIS IS ASSOCIATED WITH A COLD FRONT OVER LAKE ONTARIO AND LAKE ERIE AT 18Z MOVING INTO CENTRAL NY. FRONT WILL STALL AND RAIN WILL BECOME STEADIER AND MORE WIDESPREAD OVER THE REGION AND CIGS WILL LOWER TO IFR. AN AREA OF LOW PRESSURE WILL MOVE UP THE FRONT BRINGING WIDESPREAD LIGHT TO MODERATE RAIN AND LOW IFR CIGS. CONDITIONS WILL BEGIN TO IMPROVE FROM THE S AND W TOWARD 18Z AS THE LOW CENTER MOVES OFF TO THE NE. -BMW LONG TERM /SUNDAY NIGHT - THURSDAY/... FOLLOWED HPC GUIDENCE. PERIOD LOOKS UNSETTLED. SUNDAY NIGHT COLD FRONT MOVES OFF THE E COAST WITH COLD ADVECTION CROSSING THE LAKES DEVELOPING LAKE ENHANCED CLOUDS AND SHOWERS MONDAY AND TUESDAY AS UPPER LOW MOVES ACROSS AREA. TEMPERATURES WILL COOL ENOUGH BY TUE FOR SNOW TO MIX INTO SHOWERS DURING THE DAY TUESDAY AND WEDNESDAY WITH JUST CHANCE SNOW SHOWERS OVERNIGHT. UPPER LOW MOVES OFF COAST WED WITH LAKE ENHANCED CLOUDS AND SHOWERS CONTINUING AND DIMINISHING INTO THURSDAY. TEMPERATURES WARMING BY THURSDAY BUT STILL BELOW SEASONAL NORMALS. -BMW && .BGM WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH FOR NYZ009-037 FROM 6 AM FRIDAY TO 6 AM SATURDAY. PA...NONE. && $$ AVIATION...DJP ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 624 PM EDT THU OCT 19 2006 .SHORT TERM /REST OF TONIGHT/... UPDATED ZONES/GRIDS TO REMOVE AFTERNOON WORDING AND INCLUDE CHC OF EVENING TSRA ACROSS MUCH OF CWA THIS EVENING. RUC MODEL SOUNDINGS INDICATE STEEP MID LEVEL LAPSE RATES WILL CONTINUE UNTIL LATE EVENING. RRM && .PREV DISCUSSION... /ISSUED 413 PM EDT THU OCT 19 2006/ SHORT TERM /TONIGHT - SUNDAY/... ACTIVE WEATHER CONTINUES IN THE SHORT TERM. A STRONG COLD FRONT IN FAR WRN NY AND PA WILL SLOWLY MOVE EAST TONIGHT. AHEAD OF THE FRONT IS A LINE OF SHOWERS AND THUNDERSTORMS IN THE UNSTABLE AIR. SKIES PARTIALLY CLEARED WITH TEMPS RISING TO NEAR 70. LIS HAVE GONE NEGATIVE. LARGER AREA OF RAIN IN OHIO VALLEY WILL MOVE NE AHEAD OF A DEVELOPING AND INTENSIFYING LOW IN THE SE US. RAIN TO GET HERE THIS EVENING AND CONTIUE INTO FRIDAY MORNING. THIS LONG PERIOD OF RAIN WILL DROP OVER AN INCH EVERYWHERE WITH A STRIP CLOSE TO 2 INCHES FROM SW TO NE ELM TO UCA. THIS STRIP COULD SHIFT SOME DEPENDING ON WHERE THE SFC LOW TRACKS. FOR NOW THE TRACK OF THE LOW WILL BE OUR SE CWA FRI MORNING. MOST MODELS HAVE SIMILAR TRACKS. FOR ENDING TIME GFS FASTEST MIDDAY WITH NAM IN THE AFTN. THIS AMOUNT OF RAIN ONLY EXPECTED TO RAISE THE MOHAWK AT UTICA TO OVER FLOOD STAGE. THE RIVER ALREADY RUNNING HIGH WITH DELATA DAM FULL. OTHER STREAMS AND RIVERS WILL EXPERIENCE RISES BUT ARE NOT EXPECTED TO FLOOD. WITH THE LOW DEEPENING OVER NEW ENGLAND FRI PM...WINDS WILL PICK UP ESPECIALLY IN THE E. STILL BELOW ADVISORY CRITERIA BUT THIS WILL BRING IN THE COLD AIR FASTER. FRI NGT SOME SHOWERS POSSIBLE WHICH COULD CHANGE TO SNOW. POPS ARE AT 20 PERCENT WITH MARGINAL LAKE INSTABILITY. THIS WILL BE SHORT SHOT OF COLD AIR WITH WAA ON SATURDAY AHEAD OF THE NEXT SYSTEM. SFC HIGH BUILDS WITH WEAK UL RIDGING. FOR SUNDAY DIFFERENCES BETWEEN THE MODELS ON TIMING OF PRECIP. FOR NOW WENT WITH CHC POPS EVERYWHERE. THE NEXT STRONG COLD FRONT WILL CROSS THE CWA SUNDAY NIGHT. GFS BRINGS IN RAIN EARLY SUNDAY WITH THE NAM HOLDING OFF UNTIL AFTN. TAC AVIATION /191800Z - 201800Z/... CIGS ARE VARYING FROM 030-035 OVER THE VALLEYS TO 015-020 OVER THE MOUNTAINS. AREA OF MVFR CIGS AND SHOWERS WITH ISOLD TSTMS WILL MOVE ACROSS THE AREA BETWEEN 18Z AND 00Z. THIS IS ASSOCIATED WITH A COLD FRONT OVER LAKE ONTARIO AND LAKE ERIE AT 18Z MOVING INTO CENTRAL NY. FRONT WILL STALL AND RAIN WILL BECOME STEADIER AND MORE WIDESPREAD OVER THE REGION AND CIGS WILL LOWER TO IFR. AN AREA OF LOW PRESSURE WILL MOVE UP THE FRONT BRINGING WIDESPREAD LIGHT TO MODERATE RAIN AND LOW IFR CIGS. CONDITIONS WILL BEGIN TO IMPROVE FROM THE S AND W TOWARD 18Z AS THE LOW CENTER MOVES OFF TO THE NE. -BMW LONG TERM /SUNDAY NIGHT - THURSDAY/... FOLLOWED HPC GUIDENCE. PERIOD LOOKS UNSETTLED. SUNDAY NIGHT COLD FRONT MOVES OFF THE E COAST WITH COLD ADVECTION CROSSING THE LAKES DEVELOPING LAKE ENHANCED CLOUDS AND SHOWERS MONDAY AND TUESDAY AS UPPER LOW MOVES ACROSS AREA. TEMPERATURES WILL COOL ENOUGH BY TUE FOR SNOW TO MIX INTO SHOWERS DURING THE DAY TUESDAY AND WEDNESDAY WITH JUST CHANCE SNOW SHOWERS OVERNIGHT. UPPER LOW MOVES OFF COAST WED WITH LAKE ENHANCED CLOUDS AND SHOWERS CONTINUING AND DIMINISHING INTO THURSDAY. TEMPERATURES WARMING BY THURSDAY BUT STILL BELOW SEASONAL NORMALS. -BMW && .BGM WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH FOR NYZ009-037 FROM 6 AM FRIDAY TO 6 AM SATURDAY. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 1134 AM EDT THU OCT 19 2006 .SHORT TERM /REST OF TODAY/... WILL ISSUE UPDATE...MAINLY TO ACCOUNT FOR ISSUANCE OF FLOOD WATCH ACROSS NORTHERN COUNTIES...AND TO ADD HEAVY RAIN MENTION IN DATABASE/DATABASE PRODUCTS FOR TONIGHT/FRI. BASED ON ANTECEDENT CONDITIONS...WHICH INCLUDE HIGH RIVER LEVELS FROM TUESDAY NIGHT/S 1 TO 3 INCHES OF RAIN...IN ADDITION TO THE PROSPECTS OF AN ADDITIONAL 2 TO 3 INCHES OF RAINFALL ACROSS NORTHERN AREAS...WE HAVE ISSUED THE FLOOD WATCH FOR NORTHERN COUNTIES EFFECTIVE FROM 6 AM EDT/FRI TO 6 AM EDT/SAT. OTHERWISE...IN THE NEAR-TERM...HAVE BACKED OFF A BIT ON PRECIP ONSET FROM THE CAPITAL DISTRICT SOUTHWARD...WHICH MAY NOT OCCUR UNTIL LATER THIS EVE. ACROSS THE SOUTHERN ADIRONDACKS...SOME SHOWERS ARE ALREADY GRAZING EXTREME NORTHERN HERKIMER COUNTY...WITH ADDITIONAL SHOWERS DEVELOPING UPSTREAM. THUS...DO EXPECT AT LEAST SOME SHOWERS ACROSS THE ADIRONDACKS BY MID-LATE AFTERNOON...AS SHALLOW FRONTAL BOUNDARY GRADUALLY SAGS SE. AS FOR SKY CONDITIONS...SOME BREAKS IN THE LOW LEVEL CLOUDS WERE DEVELOPING JUST S OF THE CAPITAL DISTRICT...WITH LATEST RUC INDICATING POTENTIAL FOR ADDITIONAL BREAKS TO DEVELOP ACROSS THE LOWER MID HUDSON VALLEY. THUS...KEPT EXPECTED MAX TEMPS SIMILAR TO PREVIOUS FORECAST ISSUANCE...WHICH GENERALLY RANGE FROM THE LOWER/MID 60S ACROSS THE CAPITAL DISTRICT...TO UPPER 60S TO THE S. && .PREV DISCUSSION... /ISSUED 315 AM EDT THU OCT 19 2006/ SYNOPSIS...A COLD FRONT, OVER EXTREME WESTERN NEW YORK, WILL SLOWLY HEAD EAST, AND STALL OVER THE LISTENING AREA BY LATE TODAY. AN AREA OF LOW PRESSURE WILL FORM ALONG THIS BOUNDARY TO OUR SOUTH, THEN TRACK UP ALONG THE FRONT, JUST TO OUR EAST, ON FRIDAY. THIS SCENARIO WILL BRING ANOTHER ROUND OF RAIN TONIGHT, LASTING INTO FRIDAY EVENING. ENOUGH COLD AIR AT THE END MIGHT ALLOW THE RAIN TO SWITCH BRIEFLY TO SNOW WELL TO THE NORTH AND WEST OF ALBANY BEFORE ENDING. SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...CLOUDS HAVE HUNG IN TOUGH ACROSS OUR REGION OVERNIGHT...KEEPING TEMPERATURES FROM FALLING OUT OF THE 50S. THESE CLOUDS LOOK TO LINGER INTO TODAY...AND BY THE TIME THEY WERE TO BURN OFF, MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE FRONT, WILL LIKELY BE OVERHEAD. WITH PERSISTENT CLOUDS, WILL CONTINUE THE IDEA OF GOING LOWER THAN MAV NOS, BUT NOT BY MUCH, AS IT HAS APPARENTLY CAUGHT ON TO THE TREND. WILL KEEP A LOT OF CONTINUITY FROM THE PREVIOUS PACKAGE. THE FRONT STILL LOOKS TO BECOME ANA AS IT COMES INTO OUR AREA (AS WINDS ALOFT ALIGN WITH IT). WE DO NOT EXPECT MUCH SHOWER ACTIVITY UNTIL LATER IN THE DAY, AND PROBABLY NOT UNTIL NEAR DARK FROM THE HUDSON VALLEY AND POINTS EASTWARD. TONIGHT, THE SHORT WAVE, NOW FOUND JUST NORTH OF TEXAS, WILL INITIATE CYCLOGENESIS AS IT INTERACTS WITH THE INCREASINGLY BAROCLINIC ZONE. A PRETTY POTENT LOW PRESSURE WILL TRACK ALONG THE FRONT, NEAR THE I-95 CORRIDOR. THE BEST FRONTOGENTIC FORCING LOOKS TO BE ACROSS OUR NORTHEASTERN AREAS. NEVERTHELESS PW VALUES OF 1.5 INCHES OR MORE, WILL ISENTROPICALLY LIFT ACROSS THE ENTIRE REGION BRINGING THE POTENTIAL FOR AN INCH OR BETTER OF RAINFALL. THE AIR MIGHT BE STILL BE COLD ENOUGH FOR A BRIEF SWITCH OVER TO SNOW ACROSS MAINLY OUR ADIRONDACKS LATER FRIDAY, BUT ANY ACCUMULATIONS FROM THIS VANTAGE POINT LOOK FAIRLY LIGHT. MORE ABOUT THE RAINFALL CAN BE FOUND IN OUR HYDROLOGY SECTION. BOTH MODELS WIND THE STORM UP QUITE A BIT AS IT REACHES THE GULF OF MAINE LATE FRIDAY (THE NAM IS A BIT DEEPER). EXPECT GUSTY NW WINDS TO PERK UP AND BUFFET THE REGION BY FRIDAY NIGHT, WHICH WILL HELP PLUCK THE INCREASINGLY COLORFUL LEAFS RIGHT OFF THE TREES. AT THIS POINT, THE WIND LOOKS TO REMAIN BELOW ADVISORY/WARNING CRITERIA, BUT THE DAY CREW NEEDS TO REEXAMINE THE WINDS. ONE CHANGE WAS TO ADD A CHANCE OF THUNDER TO ALL OUR ZONES FRIDAY MORNING. WHILE SBCAPES ARE MARGINAL AT BEST...STRONG DYNAMICS AND LOW LEVEL SHEAR COULD PRODUCE LOW TOP STORMS, ESPECIALLY S AND E OF ALBANY. THERE IS EVEN AN OUTSIDE CHANCE THAT ONE OR TWO OF THESE STORMS COULD BECOME BRIEFLY SEVERE, BUT NOT ENOUGH OF A THREAT TO HIGHLIGHT AT THIS TIME. HOWEVER, WILL MENTION IN OUR HAZARDOUS WEATHER OUTLOOK (HWO). BY AFTERNOON, THE WARM AIR SECTOR SHOULD HAVE PUSH FURTHER EAST WITH ANY THREAT OF THUNDER ENDING AS COLDER AIR BEGINS WORKING IN. TEMPERATURES MIGHT ACTUALLY FALL IN SOME PLACES DURING THE DAY ON FRIDAY. ATTEMPTED TO BLEND THIS TREND WITH BRIEFLY HOLDING TEMPS S AND E OF ALBANY, BEFORE THEY TOO LIKELY FALL LATER ON. LOWER POPS A BIT FRIDAY NIGHT, GOING ONLY SLIGHT CHANCE IN VALLEY LOCATIONS AND CHANCES ACROSS THE HIGHER TERRAIN DUE TO POSSIBLE WRAP AROUND. HAVE ENDED ALL PCPN BY 06Z. NICE WEATHER LOOKS TO FOLLOW SATURDAY AS HIGH PRESSURE BRIEFLY BUILD IN. WITH H8 TEMPS PROGGED TO BE AROUND 0C (SLIGHT COLDER ON THE GFS AND SLIGHTLY WARMER ON THE NAM) HAVE LOWERED TEMPS A CATEGORY PER BOTH MAV/MET OUTPUT. STILL...IT WILL BE THE NICER OF THE TWO WEEKEND DAYS. LONG TERM /SUNDAY THROUGH WEDNESDAY/...BY SUNDAY, THE NEXT WEATHER MAKER, LOOKING MORE LIKE CLIPPER, ARRIVES FROM THE GREAT LAKES. EARLIER RUNS HAD THIS FEATURE SLOWING DOWN, WHILE ENERGY FROM THE SOUTHERN BRANCH BECOME INJECTED INTO IT. BOTH THE EUROPEAN AND LATEST GFS NOW INDICATE THE TWAIN SHALL NEVER MEET, UNTIL WELL OFFSHORE. THIS WOULD MEAN ONLY A CLIPPER TYPE STORM WOULD AFFECT US LATE SUNDAY INTO EARLY MONDAY AS ANY SECONDARY COASTAL DEVELOPMENT WOULD SLIDE WELL TO OUR SOUTH AND EAST. CONSEQUENTLY THE ANTICIPATED RAINFALL WOULD LIGHTER. ON THE OTHER HAND, THE POLAR VORTEX, INITIALLY FORECAST TO EAST OF HUDSON BAY, IS NOW FORECAST TO MOVE OVER OUR HEAD! THIS CHANGE LOOKS A TAD UNREALISTIC AND THEREFORE WE WILL NOT TINKER WITH THE EXTENDED, BUT WAIT TO SEE IF THE NEXT SET OF RUNS CONTINUES TO INDICATE THESE CHANGES. AVIATION...CLOUD DECK PERSISTS OVER THE AREA UNDER STRONG INVERSION. LOOKING AT VFR CONDITIONS WITH CIGS OF 3500 FEET. MAY GET SOME MVFR FOG AROUND SUNRISE THIS MORNING. SHOULD HAVE SOME IMPROVEMENT TODAY WITH OVC DECK GOING TO BKN BUT HIGH CLOUDS WILL BE STREAMING IN AHEAD OF NEXT SYSTEM. EXPECT CONDITIONS TO LOWER TO MVFR LATE THIS AFTERNOON/EARLY THIS EVENING AS RAIN MOVES AND EVENTUALLY LOWERING TO IFR OVERNIGHT. FIRE WEATHER...FUELS REMAIN EXCESSIVELY MOIST ACROSS THE REGION WITH LITTLE OPPORTUNITY FOR THEM TO DRY FURTHER. RH VALUES WILL ONLY DROP TO AROUND 50 PERCENT THIS AFTERNOON...HIGHER ACROSS THE MOUNTAINS...THEN RISE BACK TO BETWEEN 90-100 PERCENT TONIGHT. TOMORROW...WITH MORE RAIN EXPECTED...RH VALUES WILL BE HIGHER THAN TODAY. A S WIND AROUND 10 KTS BY THIS AFTERNOON...WILL GRADUALLY BACK TO THE NW AND INCREASE TO AROUND 15 KNOTS WITH GUSTS TO 25 KNOTS BY LATE FRIDAY. DRY WEATHER IS EXPECTED SATURDAY WITH A GRADUAL SUBSIDING OF A GUSTY NW WIND. HYDROLOGY...THE SOUTHERN ADIRONDACKS AND CENTRAL MOHAWK VALLEY ARE THE AREAS OF CONCERN AFTER RECEIVING THE HEAVIEST RAINS TUESDAY AND TUESDAY NIGHT WITH 1 TO 3 INCHES. LOOKING AT ANOTHER WIDESPREAD SOAKING RAINFALL TONIGHT THROUGH MUCH OF FRIDAY AS A COLD FRONT GRADUALLY MOVES ACROSS THE REGION AS A WAVE OF LOW PRESSURE MOVES NORTHWARD ALONG THE BOUNDARY. BY FRIDAY EVENING...THE GFS HAS THE HEAVIEST AMOUNTS ACROSS THE ADIRONDACKS 1 1/2 TO 2 INCHES...WITH AROUND AN INCH ACROSS THE REST OF THE FORECAST. THE WRF HAS 1 1/2 TO 2 1/2 INCHES ACROSS MUCH OF THE FORECAST...GENERALLY THE CATSKILLS AND CAPITAL REGION NORTH AND WESTWARD. FLASH FLOOD GUIDANCE FOR SOUTHERN HERKIMER AND FULTON COUNTIES ARE THE LOWEST FOR 24-HOUR PERIOD WITH ONLY 2 1/2 INCHES...SO EXPECTED QPF APPROACHING THAT VALUE. LOOKING AT MORE RUNOFF WITH THIS SYSTEM AS GROUND WET FROM LAST ONE. WILL CONTINUE WITH FLOOD POTENTIAL OUTLOOK STATEMENT (ESF) AT THIS TIME. ANOTHER SYSTEM IS EXPECTED TO BRING MORE RAINFALL LATE IN THE WEEKEND INTO EARLY NEXT WEEK. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NY...FLOOD WATCH FOR NYZ032-033-038>043-048>050-082>084 FROM 6 AM FRIDAY TO 6 AM SATURDAY. VT...NONE. && $$ SHORT TERM...KL ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LUBBOCK TX 1031 AM CDT THU OCT 19 2006 .UPDATE... UPDATE TO GRIDS/TEXT TO REMOVE MORNING PRECIP WORDING. ALSO HAD TO ADJUST SKY COVER FOR PERSISTENT AREA OF STRATUS ACROSS THE WRN AND CNTL ZONES. RUC AND WRF SUGGEST THIS AREA COULD HANG AROUND AS LATE AS 18Z/19Z. DECREASING CLOUDS OR CLEARING WORDING DROPPED INTO THE ZONE TEXT FOR THOSE AREAS. STRATUS MAY END UP HAVING A SMALL EFFECT ON TEMPS FOR TODAY...BUT FOR NOW TRENDS SEEMED GOOD ENOUGH TO LEAVE ALONE. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 445 AM EDT FRI OCT 20 2006 .DISCUSSION... MAIN FCST CONCERNS ARE PCPN CHANCES/TYPE TODAY THROUGH THE WEEKEND. WV IMAGERY AND RUC ANALYSIS INDICATED A CLOSED MID/UPPER LEVEL LOW WEST OF JAMES BAY AND A BROAD TROUGH ACROSS THE CNTRL CONUS WITH NUMEROUS EMBEDDED SHRTWVS. A BAND OF MID CLOUDS WAS MOVING THROUGH WI AND UPPER MI AHEAD OF A WEAK SHRTWV FROM SRN MN INTO IA. AN AREA OF LIGHT SNOW FROM SE MANITOBA INTO FAR NRN MN WAS SUPPORTED BY WEAK TO MODERATE 700-300 MB QVECTOR CONV WITH ANOTHER SHRTWV ALONG WITH UPPER LEVEL DIV VCNTY LEFT EXIT OF 65-70 KT 300 MB JET AND 290K-295K ISENTROPIC LIFT. THE MOST PROMINENT UPSTREAM SHRTWV ASSOCIATED WITH A 120 KT 300 MB JET WAS PLUNGING SE FROM BC THROUGH THE NRN ROCKIES. AT THE SFC...A WEAK RDG EXTENDED FROM IL TO W UPPER MI AHEAD OF LOW PRES LOCATED OVER NW MN. RADAR SHOWED LIGHT LAKE EFFECT PCPN FROM THE TIP OF THE KEWEENAW TOWARD GRAND MARAIS WAS SLOWLY SHIFTING NE AS CBL WINDS BACK AND SHOULD REMAIN OFFSHORE. OTHERWISE...SATELLITE/OBS INDICATED PERSISTENT LOW CLOUDS BENEATH STRONG 850 MB INVERSION. TODAY...THE 00Z NAM AND GFS SHOW WEAK/MODERATE 700-300 MB QVECTOR CONV AHEAD OF A MID LEVEL TROUGH AXIS MOVING ACROSS UPPER MI. HOWEVER...MDLS ALSO SUGGEST THAT SINCE THE SFC-850 MB TROUGH AND ASSOCIATED LOWER LVL ISENTROPIC LIFT WEAKENS...THE PROMINENT 850-700 DRY LAYER WILL PERSIST...REDUCING POTENTIAL FOR ANY PCPN. BY LATER IN THE AFTERNOON THERE MAY BE ENOUGH 285K-290K LIFT/MOISTENING TO SUPPORT SOME LIGHT PCPN ACROSS MAINLY W AND S UPPER MI. SO...TIMING AND POPS WERE SCALED BACK. EVEN THOUGH 1000-850 THICKNESS VALUES AND FREEZING HEIGHTS POINT TO MAINLY RAIN...WET-BULB TEMPS WILL REMAIN LOW ENOUGH SO THAT MIX WITH SNOW WILL BE POSSIBLE...ESPECIALLY OVER HIGHER TERRAIN. TONIGHT...MDLS BRING THE TROUGH INTO CNTRL UPPER MI BY 12Z. BY LATE TONIGHT...CAA DROPPING 850 MB TEMPS TO AROUND -6C WITH DEVELOPING NNW FLOW ALONG WITH 900-800 FGEN WILL CONTINUE TO SUPPORT PCPN CHANCES WITH THE HIGHEST POPS LATE OVER THE WEST THIRD. OVER THE REST OF THE CWA...ANOTHER VORT LOBE AND ASSOCIATED WEAK QG FORCING ALONG WITH LOW LEVEL CONV ALONG AND AHEAD OF THE TROF ALSO WARRANT AT LEAST 20-30 POPS. SAT INTO SAT NIGHT...MDL DIFFERENCES BECOME MORE SIGNIFICANT AS THE UKMET AND ESPECIALLY THE NAM SUGGEST THE SHRTWV(ORIGINATING OVER THE NRN ROCKIES)AND RESULTING SFC LOW DEVELOPMENT WILL BE STRONGER AND FARTHER NW. THE MORE CONSISTENT GFS...SUPPORTED BY THE ECMWF AND LARGE MAJORITY OF SREF(PER HPC)...WAS PREFERRED. SO...EXPECT THE SYSTEM WOULD REMAIN S OF UPPER MI OR ONLY BRUSH THE ERN PORTION OF THE CWA. OTHERWISE...BAND OF WEAK QVECTOR CONV AND FGEN WILL KEEP CHANCES OF LGT PCPN GOING SAT. ALTHOUGH 850 MB TEMPS DROP TO NEAR -8C (LEADING TO LK-850 MB DELTA/T AROUND 17C) AND INVERSION HGT PROGGED NEAR 800 MB(6K-7K FT)...MAINLY ACYC FLOW AND SUBSIDENCE/ WEAK QVECTOR DIV/ BY SAT NIGHT WILL NOT BE TOO FAVORABLE FOR LAKE EFFECT PCPN. SO...GOING CHANCE POPS STILL SEEM ON TRACK. SUN...THE GLOBAL MDLS BRING THE MID LVL CLOSED LOW SLOWLY TOWARD THE UPPER GREAT LAKES. INCREASING SFC-700 MB MOISTURE AND CLIMBING INVERSION HEIGHTS DURING THE DAY WILL BE MORE FAVORABLE FOR LES POTENTIAL EVEN THOUGH 850 MB TEMPS REMAIN NEAR -7C. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 347 AM CDT FRI OCT 20 2006 .DISCUSSION... WEAK WAVE WITH BACK EDGE OVER WESTERN MINNESOTA MOVING ACROSS AREA THIS MORNING WITH SCATTERED LIGHT SHOWERS. BAND OF SHOWERS CORRELATING FAIRLY WELL WITH 06Z RUC FORECAST OF 290 ISEN SURFACE. BEST SATURATION WITH THIS MOVING ACROSS EAST CENTRAL MN INTO WESTERN WI THIS MORNING. MAY BE SOME TEMPORARY CLEARING BEHIND THIS BUT WOULD EXPECT CLOUDS TO INCREASE OVER MUCH OF THE AREA WITH STRONG WAVE HEADING TOWARD WY. SOME ISENT LIFT STARTS AHEAD OF THIS OVER FAR S MN LATE THIS AFTERNOON. LOOKS LIKE A SIG WAVE AND THERE WAS SOME LIGHTNING AS IT PASSED ACROSS ID LAST NIGHT. STILL LOOKS LIKE A CLOSE CALL WITH THIS..BUT WILL NEED TO KEEP A MID RANGE POP ACROSS SOUTHERN TIER TONIGHT INTO EARLY SATURDAY. QUICK LOOK AT 06Z NAM SHOWING GOOD LIFT ACROSS NORTH CENTRAL IA. LOW LEVEL THICKNESS ON THE HIGH SIDE INITIALLY BUT WILL KEEP WITH THE TREND OF A RAIN AND SNOW MIX LATE TONIGHT INTO SATURDAY. GFS GUID TEMPS LOOK A LITTLE HIGH TODAY IN A FEW SPOTS..BUT IF THERE IS A FAR AMOUNT OF SUN FOR A WHILE..THEN THERE MAY BE MORE TEMPS CLOSE TO 50. FAIRLY STRONG QG DIV BEHIND SYSTEM OVER W HALF OF CWA ON SATURDAY AFTERNOON...SO HAVE CUT BACK ON CLOUDS SOME..BUT COULD END UP BEING LESS CLOUDS. LATER FORECASTS CAN ASSESS THIS. COLD AIR FILLS IN ON SUNDAY WITH COLD CYCLONIC FLOW. A FEW SNOW SHOWERS AS WELL. TEMPS MAY BE MORE TOWARD UPPER 30S FOR AFTERNOON. LONGER TERM...TUESDAY THROUGH FRIDAY 00Z GFS AND ECMWF IN GOOD AGREEMENT ON OVERALL UPPER AIR PATTERN... AT LEAST EARLY ON. UPPER LOW OVER THE GREAT LAKES SHIFTS EAST TUE/WED PERIOD...ALLOWING SOMEWHAT WARMER TEMPERATURES/MODERATION TO MOVE INTO THE AREA. SURFACE RIDGING OVER THE AREA WILL PROVIDE COLD AND DRY START TO THE PERIOD/MON/ WITH FORECAST HIGHS MODERATING THROUGH THE 40S TO AROUND 50 AGAIN BY LATE IN THE WEEK. NEXT SIGNIFICANT TROUGH MOVES INLAND OVER THE FAR NORTHWEST LATER TUESDAY AND DIGS RAPIDLY SOUTH OVER THE WESTERN CONUS THROUGH THE END OF NEXT WEEK. THIS WOULD FAVOR A FAIRLY LARGE STORM SYSTEM MOVING OUT INTO THE MIDDLE PLAINS LATER IN THE WEEK. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/DWE mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1051 AM EDT FRI OCT 20 2006 .SHORT TERM /REST OF TODAY/... KLWX 88D SHOWING LINE OF SHRA MOVING ACRSS NE PORT OF CWA ATTM. SFC OBS ARE GUSTNG UP TO 25-35 KTS BEHIND FRNT...WHICH MOVED THRU IAD DURING THE PAST 30 MINUTES. I WILL BE DECREASING SKY COVER TDY AS FRONT HAS MOVED THRU MUCH OF THE CWA AND XPCTNG SCT-BKN STRATO CU BEHIND IT. FROM LATEST RUC AND NAM PROFILES...ATTM AM NOT XPCTNG WIND ADSRY CRIT FOR GUSTS (40KTS) ALTHOUGH IT WILL BE CLOSE TO THIS THRESHOLD THIS AFT IN THE DCA-BWI-APG CORRIDOR AND N CHES BAY. AM NOT EXPECTING ANY CSTL FLOODING WITH THIS EVENT AS LEVELS ARE BLO CRIT AND JUST MAY REACH MINOR THRESHOLD AT TIME OF HIGH TIDE TONIGHT. && .PREV DISCUSSION... /ISSUED 347 AM EDT FRI OCT 20 2006/ SHORT TERM /TODAY THROUGH TONIGHT/... SURFACE ANALYSIS FROM 03Z SHOWS A COLD FRONT EXTENDING FROM NEW YORK SOUTH ACROSS WEST VIRGINIA AND INTO THE DEEP SOUTH. A SECONDARY DEVELOPING WAVE WAS OVER WEST VIRGINIA. TEMPERATURES AND DEW POINTS AT 06Z WERE IN THE LOWER 60S. REGIONAL RADAR SHOWS PRECIPITATION ACROSS NEARLY THE ENTIRE FORECAST AREA. WATER VAPOR SATELLITE IMAGERY SHOWS A SPLIT DRY SLOT MOVING NORTHEAST FROM KENTUCKY AND TENNESSEE. THE COLD FRONT TO THE WEST WILL SWING THROUGH THE REGION LATER THIS MORNING. THE DEEPENING WAVE IN WEST VIRGINIA...INCREASING LOW AND MID LEVEL JET...AND AN APPROACHING SHORT WAVE OVER THE OHIO RIVER VALLEY WILL COMBINE FOR A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN FORECAST AREA. THE THREAT SHOULD REMAIN CONFINED TO POINTS ALONG AND EAST OF INTERSTATE 95. WITH LIMITED SURFACE INSTABILITY AND LAPSE RATES...ESPECIALLY CONSIDERING THE TIME OF DAY...NOT EXPECTING A WIDESPREAD SEVERE THREAT. STORMS SHOULD BE ISOLATED AND RATHER SHALLOW. HOWEVER...WITH INCREASING LOW LEVEL WINDS...STORMS WILL NOT NEED TO BE THAT DEEP TO USHER STRONGER WINDS. CLOUDS WILL DECREASE AND WINDS WILL INCREASE ONCE THE FRONT PUSHES EAST OF THE AREA LATE THIS MORNING. TEMPERATURES WILL ALSO BEGIN TO FALL BY NOON. MOST HIGH TEMPERATURES WILL BE OBSERVED LATE THIS MORNING. BY THIS EVENING...CLOUDS WILL FOR THE MOST PART WILL HAVE MADE THEIR WAY EAST. THIS WILL SET UP NICELY FOR A GOOD RADIATIONAL COOLING NIGHT. TEMPERATURES WILL REACH DOWN TO THE LOWER TO MID 40S BY MORNING. ANOTHER ELEMENT TO WATCH IS WIND GUSTS AT HIGHER ELEVATIONS. EXPECT THAT GUSTS SHOULD REMAIN BELOW ADVISORY CRITERIA...HOWEVER WILL INCLUDE A MENTION IN THE HWO FOR GUSTS TO 30 KNOTS. AVIATION... CEILINGS AND VISIBILITIES WILL IMPROVE LATE THIS MORNING AS THE COLD FRONT PUSHES EAST OF THE REGION. SOUTHERLY WINDS WILL INCREASE THROUGH LATE MORNING BEFORE SHIFTING WEST AND THEN NORTHWEST BY AFTERNOON. RAIN WILL BEGIN TO TAPER OFF LATE THIS MORNING AND SHOULD BE EAST OF BALTIMORE TERMINALS BY NOON. AN INCREASING LOW LEVEL JET AND DOWNSLOPING WILL GIVE WAY TO NORTHWEST WINDS GUSTING BETWEEN 30 AND 35 KNOTS THIS AFTERNOON. NORTHWEST WINDS WILL GRADUALLY DIMINISH WITH SUNSET. COASTAL FLOODING... TIDES ALONG THE TIDAL POTOMAC RIVER AND MARYLAND CHESAPEAKE BAY WILL CONTINUE TO RUN BETWEEN A HALF FOOT AND A FOOT ABOVE ASTRONOMICAL VALUES THROUGH MID DAY. SOUTHERLY WINDS WILL SHIFT FROM THE WEST AND LATER NORTHWEST THIS AFTERNOON...ALLOWING TIDES TO RETURN TO NORMAL VALUES BY AFTERNOON. LONG TERM /SATURDAY THROUGH THURSDAY/... HIGH PRES WILL BE CENTERED OVER BECKLEY WEST VIRGINIA SATURDAY MORNING WITH OUR NEXT COLD FRONT MOVING FROM THE PLAINS INTO THE MIDWEST AT THAT TIME. MAYBE SOME HIGH CLOUD BLOWOFF FROM THAT SYSTEM SAT AND SAT NIGHT HERE... BUT NOT MUCH ELSE. SHOULD BE A PLEASANT SLIGHTLY COOL OCTOBER DAY ON SATURDAY. CHANGES COME ON SUNDAY AS FIRST A PREFRONTAL TROF MOVES THRU SUN MORN...FOLLOWED BY THE COLD FRONT SUN EVE. THAT WILL BRING SOME SHOWERS...AND THEN SOME DECENT COLD ADVECTION AS 850MB TEMPS DROP FROM 6C ABOVE SUNDAY MIDDAY TO AROUND 4C BELOW MONDAY MIDDAY. COULD EVEN BE SOME MOUNTAIN SNOW SHOWERS WEST OF THE ALLEGHENY FRONT ON MONDAY AND TUESDAY WITH THE UPSLOPE FLOW. A WEAK REINFORCING TROF MOVES THROUGH EARLY TUESDAY. SHOULD BE DRY THROUGH THE REST OF THE WEEK WITH HIGH PRES OVER THE REGION THROUGH FRIDAY. MARINE... A GALE WARNING IS IN EFFECT FOR THE TIDAL POTOMAC RIVER AND MARYLAND CHESAPEAKE BAY LATER THIS MORNING THROUGH THIS EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT FOLLOWING THE GALE WARNING THROUGH LATE TONIGHT. SOUTHERLY WINDS WILL INCREASE THROUGH THE MORNING HOURS AHEAD OF THE APPROACHING COLD FRONT. SOUTHERLY WINDS MAY OCCASIONALLY GUST TO BETWEEN 15 AND 20 KNOTS THIS MORNING BEFORE SHIFTING TO THE WEST AND NORTHWEST BY AFTERNOON. VISIBILITIES ACROSS THE WATERS WILL IMPROVE ONCE THE FRONT MOVES THROUGH. A COLD FRONT WILL CROSS THE WATERS SUNDAY NIGHT. FOLLOWING THAT... SMALL CRAFT CONDITIONS ARE POSSIBLE BOTH ON MON AND TUE WITH THE INITIAL SHOT AND THE REINFORCING SHOT OF COLD AIR DURING THE EARLY WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...GALE WARNING FOR ANZ530>537 UNTIL 8 PM FRIDAY. ...SMALL CRAFT ADVISORY FOR ANZ530>537 FROM 8 PM FRIDAY TO 2 AM SATURDAY. && $$ SHORT TERM...LEE md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1115 AM EDT FRI OCT 20 2006 .UPDATE... AREA OF LGT RAIN/SNOW NOW INTO FAR W LK SUPERIOR BUT OVERALL IS MAKING SLOW PROGRESS TO EAST. COUPLE OF SHORTWAVES ARE NW OF CWA WITHIN BROAD TROFFING CENTERED OVR HUDSON BAY. LEADING WAVE IS OVR NE MN AND IS GENERATING AREA OF RAIN/SNOW. OTHER SHORTWAVE IS DROPPING S INTO NW ONTARIO. THIS WAVE WILL HELP KICK THE MN WAVE TO THE SE AND PUSH LGT PCPN INTO W CWA BY LATE TODAY. GOING FCST IS FINE CONCERNING THAT SCENARIO. LGT W WINDS AND H85 TEMPS AROUND -5C WITH SOME MOISTURE AROUND H85 PER TAMDAR SOUNDINGS IS YIELDING SOME LGT LK EFFECT RAIN/SNOW SHOWERS FM KEWEEENAW INTO E LK SUPERIOR PER WEAK RADAR ECHOES AND SPOTTER REPORT FM MOHAWK IN KEWEENAW COUNTY. ADDED SOME POPS OVER THESE AREAS TO START AFTN. ALSO INCREASED POPS OVR KEWEENAW BY MID AFTN AS FAVORABLE LK EFFECT SETUP REMAINS IN PLACE BENEATH INCREASINGLY FAVORABLE UPR LEVEL FORCING AS SHORTWAVE TO NW BEGINS TO MOVE INTO THE LK SUPERIOR REGION. TEMPS/WINDS/SKY NEEDED ONLY A FEW TWEAKS. && .DISCUSSION... MAIN FCST CONCERNS ARE PCPN CHANCES/TYPE TODAY THROUGH THE WEEKEND. WV IMAGERY AND RUC ANALYSIS INDICATED A CLOSED MID/UPPER LEVEL LOW WEST OF JAMES BAY AND A BROAD TROUGH ACROSS THE CNTRL CONUS WITH NUMEROUS EMBEDDED SHRTWVS. A BAND OF MID CLOUDS WAS MOVING THROUGH WI AND UPPER MI AHEAD OF A WEAK SHRTWV FROM SRN MN INTO IA. AN AREA OF LIGHT SNOW FROM SE MANITOBA INTO FAR NRN MN WAS SUPPORTED BY WEAK TO MODERATE 700-300 MB QVECTOR CONV WITH ANOTHER SHRTWV ALONG WITH UPPER LEVEL DIV VCNTY LEFT EXIT OF 65-70 KT 300 MB JET AND 290K-295K ISENTROPIC LIFT. THE MOST PROMINENT UPSTREAM SHRTWV ASSOCIATED WITH A 120 KT 300 MB JET WAS PLUNGING SE FROM BC THROUGH THE NRN ROCKIES. AT THE SFC...A WEAK RDG EXTENDED FROM IL TO W UPPER MI AHEAD OF LOW PRES LOCATED OVER NW MN. RADAR SHOWED LIGHT LAKE EFFECT PCPN FROM THE TIP OF THE KEWEENAW TOWARD GRAND MARAIS WAS SLOWLY SHIFTING NE AS CBL WINDS BACK AND SHOULD REMAIN OFFSHORE. OTHERWISE...SATELLITE/OBS INDICATED PERSISTENT LOW CLOUDS BENEATH STRONG 850 MB INVERSION. TODAY...THE 00Z NAM AND GFS SHOW WEAK/MODERATE 700-300 MB QVECTOR CONV AHEAD OF A MID LEVEL TROUGH AXIS MOVING ACROSS UPPER MI. HOWEVER...MDLS ALSO SUGGEST THAT SINCE THE SFC-850 MB TROUGH AND ASSOCIATED LOWER LVL ISENTROPIC LIFT WEAKENS...THE PROMINENT 850-700 DRY LAYER WILL PERSIST...REDUCING POTENTIAL FOR ANY PCPN. BY LATER IN THE AFTERNOON THERE MAY BE ENOUGH 285K-290K LIFT/MOISTENING TO SUPPORT SOME LIGHT PCPN ACROSS MAINLY W AND S UPPER MI. SO...TIMING AND POPS WERE SCALED BACK. EVEN THOUGH 1000-850 THICKNESS VALUES AND FREEZING HEIGHTS POINT TO MAINLY RAIN...WET-BULB TEMPS WILL REMAIN LOW ENOUGH SO THAT MIX WITH SNOW WILL BE POSSIBLE...ESPECIALLY OVER HIGHER TERRAIN. TONIGHT...MDLS BRING THE TROUGH INTO CNTRL UPPER MI BY 12Z. BY LATE TONIGHT...CAA DROPPING 850 MB TEMPS TO AROUND -6C WITH DEVELOPING NNW FLOW ALONG WITH 900-800 FGEN WILL CONTINUE TO SUPPORT PCPN CHANCES WITH THE HIGHEST POPS LATE OVER THE WEST THIRD. OVER THE REST OF THE CWA...ANOTHER VORT LOBE AND ASSOCIATED WEAK QG FORCING ALONG WITH LOW LEVEL CONV ALONG AND AHEAD OF THE TROF ALSO WARRANT AT LEAST 20-30 POPS. SAT INTO SAT NIGHT...MDL DIFFERENCES BECOME MORE SIGNIFICANT AS THE UKMET AND ESPECIALLY THE NAM SUGGEST THE SHRTWV(ORIGINATING OVER THE NRN ROCKIES)AND RESULTING SFC LOW DEVELOPMENT WILL BE STRONGER AND FARTHER NW. THE MORE CONSISTENT GFS...SUPPORTED BY THE ECMWF AND LARGE MAJORITY OF SREF(PER HPC)...WAS PREFERRED. SO...EXPECT THE SYSTEM WOULD REMAIN S OF UPPER MI OR ONLY BRUSH THE ERN PORTION OF THE CWA. OTHERWISE...BAND OF WEAK QVECTOR CONV AND FGEN WILL KEEP CHANCES OF LGT PCPN GOING SAT. ALTHOUGH 850 MB TEMPS DROP TO NEAR -8C (LEADING TO LK-850 MB DELTA/T AROUND 17C) AND INVERSION HGT PROGGED NEAR 800 MB(6K-7K FT)...MAINLY ACYC FLOW AND SUBSIDENCE/ WEAK QVECTOR DIV/ BY SAT NIGHT WILL NOT BE TOO FAVORABLE FOR LAKE EFFECT PCPN. SO...GOING CHANCE POPS STILL SEEM ON TRACK. SUN...THE GLOBAL MDLS BRING THE MID LVL CLOSED LOW SLOWLY TOWARD THE UPPER GREAT LAKES. INCREASING SFC-700 MB MOISTURE AND CLIMBING INVERSION HEIGHTS DURING THE DAY WILL BE MORE FAVORABLE FOR LES POTENTIAL EVEN THOUGH 850 MB TEMPS REMAIN NEAR -7C. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA DISCUSSION...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1024 AM EDT FRI OCT 20 2006 .UPDATED... BASED ON THE LATEST RUC DATA AND TAMDAR... LOW LEVEL COLD ADVECTION CONTINUES. TAMDAR SOUNDINGS SHOW THE INVERSION HEIGHT NEAR 6000 WITH 850 MB TEMPERATURE NEAR -5C AT 12Z. THIS IS COLD ENOUGH FOR LAKE EFFECT LIGHT RAIN SHOWERS...WHICH FOR THE MOST PART ARE MORE DRIZZLE THAN ANYTHING. SINCE THE COLD ADVECTION REMAINS TILL 16Z AND THE INVERSION HEIGHT SHOULD STAY NEAR 6000 FT THROUGH EARLY AFTERNOON I EXPECT CLOUDS AND PATCH DRIZZLE OR VERY LIGHT RAIN SHOWERS NEAR AND WEST OF US-131 TILL THE COLD ADVECTION ENDS... NEAR 16Z ...NOON. AFTER THAT THERE ARE ENOUGH HIGH AND MID CLOUDS UPSTREAM TO KEEP THE FORECAST CLOUDY THROUGH TONIGHT. I LOWERED THE HIGHS A TOUCH AS A RESULT OF THAT. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1052 AM CDT FRI OCT 20 2006 .DISCUSSION... CLOUDS HAVE BEEN GRADUALLY DISSIPATING...BUT THE EASTERN HALF OF THE CWA IS STILL OVERCAST AND NORTHERLY WINDS ARE BRINGING COOL AIR INTO THE AREA. ADJUST THE CLOUD COVER TO SHOW A SLOWER TREND. WILL LIKELY LOWER TEMPERATURES EVERYWHERE FROM 3-5 DEGREES. LEFT TEMPS SLIGHTLY HIGHER FOR THE SOUTHEAST...LOOKING AT RUC 850 ANALYSIS THE FLOW WAS FROM THE SOUTHWEST...WHICH MAY BE ENOUGH TO BOOST TEMPS A FEW EXTRA DEGREES INTO THE LOWER 60S. WENT WITH UPPER 50S NORTHEAST... NEAR 60 CENTRAL AND WEST AND LOWER 60S SOUTHEAST. WILL REMOVE ANY MORNING WORDING. WILL SEND UPDATE SHORTLY. && .AVIATION... CLOUDS WERE SLOWLY BREAKING UP ACROSS THE AREA. EXPECT CLOUDS TO LINGER THROUGH EARLY AFTERNOON FOR MEI/GTR/HBG AROUND 1500-2000FT. BEYOND 21Z VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. MORE SHOWERS MAY DEVELOP ACROSS THE AREA AFTER 18Z SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 66 42 75 52 / 0 0 6 78 MERIDIAN 67 38 76 52 / 0 0 2 70 VICKSBURG 66 42 75 53 / 0 0 10 78 HATTIESBURG 70 44 77 58 / 0 0 6 82 NATCHEZ 67 43 77 56 / 0 0 20 85 GREENVILLE 65 41 72 49 / 0 0 4 47 GREENWOOD 65 39 73 48 / 0 0 3 50 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 07/99/99 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 922 AM PDT FRI OCT 20 2006 .SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL EXIT THE REGION EARLY THIS MORNING ALLOWING AN UPPER LEVEL RIDGE TO BUILD OVER THE PACIFIC NORTHWEST. THE BENIGN RIDGE PATTERN WILL PERSIST UNTIL EARLY NEXT WEEK AS A COOL TROUGH DROPS IN FROM THE NORTHWEST. && .DISCUSSION... UPDATED ZONES TO ACCOUNT FOR MARKED CLEARING AND DISTINCTLY DRIER AIR THAT HAS INFILTRATED EASTERN WASHINGTON OUTSIDE OF THE AREA OF THE BLUE MOUNTAINS. MAINTAINED POPS MAINLY OVER SHOSHONE COUNTY AND THE CAMAS PRAIRIE FOR EARLY AFTERNOON AS SHORT WAVE SLIDES DOWN THE CONTINENTAL DIVIDE WITH DECENT DIFFLUENCE NOTED AHEAD OF IT AND MODEST OMEGAS PER THE RUC. SOME GOOD ISENTROPIC ASCENT NOTED THIS AFTERNOON ON THE RUC OVER NORTHEASTERN WASHINGTON AND THE NORTHERN IDAHO PANHANDLE...HOWEVER WITH RH VALUES ABOVE 850 MB MEAGER AT BEST...DID LITTLE BUT ADD THE CHANCE FOR SOME CLOUD DEVELOPMENT. RAISED TEMPERATURES MOST EVERYWHERE AS GOOD INSOLATION SHOULD GET US UP TO AT LEAST MOS AS COLD ADVECTION BEGINS TO WANE THIS AFTERNOON. ZONES WILL BE OUT SHORTLY. /FRIES && .AVIATION...PRIMARILY VFR CONDITIONS ARE EXPECTED TO PERSIST THRU 06Z SAT...ALTHOUGH THERE COULD BE LCL IFR CONDITIONS FROM FOG IN THE VALLEYS NORTH OF SPOKANE THRU 17Z THIS MORNING. RIDGING BUILDS OVER THE REGION TONIGHT...WITH PATCHY FOG AND IFR CONDITIONS POSSIBLE IN THE VALLEYS N AND E OF A LINE FROM KOMK-KGEG-KLWS. FX && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 58 34 51 31 54 33 / 0 0 0 0 0 10 COEUR D'ALENE 57 33 51 30 56 32 / 0 0 0 0 0 10 PULLMAN 58 34 52 31 58 34 / 0 0 0 0 0 10 LEWISTON 60 38 56 36 58 38 / 10 0 0 0 0 10 COLVILLE 55 31 53 31 56 27 / 0 0 0 0 0 10 SANDPOINT 55 31 48 29 52 29 / 0 0 0 0 0 10 KELLOGG 54 31 51 29 55 33 / 10 0 0 0 0 10 MOSES LAKE 66 33 60 34 60 34 / 0 0 0 0 0 10 WENATCHEE 67 41 61 37 61 40 / 0 0 0 0 0 10 OMAK 68 35 59 37 60 33 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 302 PM EDT FRI OCT 20 2006 .SHORT TERM (TONIGHT-SATURDAY)... CURRENTLY...WATER VAPOR IMAGERY SHOWING UPPER TROUGH TO THE NORTHEAST OF THE CWA. THE VIS SHOWS STRATUS DECK ACROSS THE EASTERN HALF OF THE CWA. CLEARING HAS MOVED INTO THE WESTERN HALF OF THE CWA...COINCIDENT WITH SURFACE HIGH PRESSURE AND WINDS BACKING TO THE SOUTHWEST. THE 925MB DEWPOINT RUC ANALYSIS MATCHES UP VERY WELL WITH THE CLOUD COVER...SO USED THIS FOR TIMING THE EXIT OF THE CLOUDS TO THE EAST. TEMPERATURES ACROSS THE EAST HAVE SUFFERED FROM THE CLOUDS AS WELL...SO THESE LOCATIONS ALREADY HAVE A HEAD START ON THE OVERNIGHT LOWS. AS HIGH PRESSURE TO OUR WEST-SOUTHWEST MOVES ACROSS THE CWA TO THE MID-ATLANTIC COAST...WINDS WILL BE LIGHT AND SWLY...SKIES WILL BE CLEAR...AND GOOD RADIATIONAL COOLING WILL TAKE PLACE. NAM AND GFS ALSO INDICATING WARM-AIR ADVECTION OVERNIGHT...SO MOISTURE MAY INCREASE SLIGHTLY...ESPECIALLY ACROSS THE WRN/SWRN CWA...TOWARD TOMORROW MORNING. NAM BUFKIT SOUNDINGS INDICATING A WIDESPREAD DENSE FOG EVENT...BUT THINK IT IS OVERDOING THE MOISTURE. MAV GUIDANCE ONLY SHOWING A MARGINAL HAZE/MIST EVENT WITH MVFR VISIBILITIES. WILL GO IN BETWEEN WITH AREAS OF FOG AFTER MIDNIGHT TOWARD MORNING CWA-WIDE. OVERNIGHT LOWS SHOULD RANGE IN THE MID 30S WITH URBAN AREAS HAVING WARMER OVERNIGHT LOWS IN THE UPPER 30S. SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES REBOUNDING NICELY UNDER A SOUTHERLY WIND. WITH GOOD WARM-AIR ADVECTION TAKING PLACE...SHOULD REACH THE LOW 60S NE TO THE UPPER 60S SW...CLOSER TO MAV NUMBERS. CLOUDS WILL INCREASE FROM THE NORTHWEST TOWARD SATURDAY NIGHT AS THE NEXT SYSTEM APPROACHES. AL .LONG TERM (SATURDAY NIGHT-FRIDAY)... SATURDAY NIGHT THROUGH MONDAY... UPPER LEVEL JET MAX DROPPING FROM SOUTHWEST CANADA INTO IDAHO WILL DEVELOP A PROGRESSIVE TROUGH OVER THE NORTHERN PLAINS AND WILL MOVE EAST TOWARD THE GREAT LAKES. ANOTHER COLD FRONT WILL SWEEP ACROSS THE LOWER OHIO VALLEY SUNDAY MORNING HOWEVER MOISTURE WILL BE LIMITED. THE LOW LEVEL FLOW WILL REMAIN OUT OF THE SOUTHWEST. THE BEST MOISTURE WILL BE SOUTH OF THE AREA AND AROUND THE SURFACE CLOD FRONT WHICH WILL MOVE ACROSS CENTRAL ILLINOIS AND NORTHERN INDIANA. FOR THIS REASON WILL ONLY MENTION CHANCE POPS WITH THE FRONTAL PASSAGE SUNDAY MORNING AND EARLY AFTERNOON. SKIES WILL CLEAR OUT BEHIND THIS...WITH TEMPERATURES DROPPING INTO THE LOWER 30S BY MONDAY MORNING. TUESDAY THROUGH FRIDAY.... EASTERN U.S. UPPER LEVEL TROUGH WILL MOVE FROM THE GREAT LAKES TO THE EAST COAST DURING THE TUESDAY THROUGH THURSDAY TIME FRAME. THIS WILL PUT THE LOWER OHIO VALLEY BACK IN A SOUTHWEST FLOW AS ANOTHER DEEP TROUGH BEGINS TO DEVELOP OVER THE NORTHERN PLAINS. IN THE LOWER ATMOSPHERE WE WILL SEE A TIGHTENING GRADIENT AS AN AREA OF LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. THE H8 FLOW WILL REMAIN OUT OF THE SOUTHWEST SO THE GULF DOES NOT COMPLETELY OPEN UP AND THE HEAVIER RAIN SHOULD STAY TO OUR SOUTH. BUT THERE WILL BE SOME OVERRIDING INTO THE REGION AND WE WILL MENTION LOW CHANCE POPS FOR THE FRIDAY TIME FRAME...PERHAPS SOONER. TEMPERATURES AT THE BEGINNING OF THIS FORECAST PERIOD WILL BE SOME 10 DEGREES BELOW NORMAL FOR THE MIDDLE OF OCTOBER BUT WILL GRADUALLY MODERATE AS THE WEEKEND APPROACHES. JA && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE GAYLORD MI 350 PM EDT FRI OCT 20 2006 .SHORT TERM FORECAST...19Z WATER VAPOR/SURFACE/RUC ANALYSIS SHOWS MID LEVEL POLAR VORTEX SPINNING JUST SOUTH OF HUDSON BAY WITH LARGE TROUGH AXIS EXTENDING ACROSS THE CENTRAL AND NORTHERN CONUS. SEVERAL LOW AMPLITUDE SHORTWAVES ROTATING AROUND PARENT CIRCULATION...ONE OF WHICH IS CROSSING THE U.P. THIS AFTERNOON WITH ANOTHER DROPPING INTO NORTHERN MINNESOTA. WEAK SURFACE RIDGE AXIS EXTENDS NORTH INTO NORTHERN MICHIGAN WITH ILL DEFINED LOW OVER CENTRAL MINNESOTA ASSOCIATED WITH NORTHERN MINNESOTA SHORTWAVE. FARTHER WEST...SHORTWAVE AND ASSOCIATED 110KT 250MB JET STREAK DIVING SOUTHEAST ACROSS THE INTERMOUNTAIN WEST (REMNANTS FROM WHICH WAS ONCE EASTERN PACIFIC TYPHOON SOULIK). LEE SIDE CYCLOGENESIS STARTING TO TAKE PLACE OVER THE HIGH PLAINS IN FAVORABLE UPPER LEVEL DIFLUENCE REGION OF AFOREMENTIONED FEATURES. CLOSER TO HOME...LAKE EFFECT RAIN SHOWERS...AT TIMES MIXED WITH SNOW IN THE HIGHER ELEVATIONS...CONTINUE TO ROTATE NORTHEAST THROUGH NORTHWEST LOWER THIS AFTERNOON AS 1000-850MB WINDS BACK TO WEST/WEST SOUTHWEST. FORECAST CONCERNS THROUGH SATURDAY CENTER ON LINGERING LAKE EFFECT POTENTIAL TONIGHT THEN ADDITIONAL PRECIPITATION CHANCES SATURDAY AS INTERMOUNTAIN/HIGH PLAINS SYSTEM EJECTS EAST TOWARDS REGION. TONIGHT...WILL CONTINUE ISOLATED MENTION OF LIGHT LAKE EFFECT RAIN SHOWERS ALONG THE IMMEDIATE LAKE MICHIGAN COASTLINE OF THE NORTHWEST LOWER AND FOR SOUTHERN SECTIONS OF EASTERN UPPER MICHIGAN THIS EVENING. INITIAL 1000-850MB WEST/WEST SOUTHWEST WINDS CONTINUE TO BACK OVERNIGHT...EVENTUALLY BECOMING SOUTHERLY AFTER 06Z. MARGINAL OVER-LAKE INSTABILITY REMAINS THIS EVENING AS 850MB TEMPERATURES GRADUALLY WARM TO -1C TO -3C BY LATE TONIGHT. LIMITING FACTORS REMAIN SUBSIDENCE INVERSION AT APPROX 850MB AND GENERAL SYNOPTIC SUBSIDENCE BEHIND DEPARTING NORTHERN LAKES SHORTWAVE. FOR LATER TONIGHT...SOUTHERLY WINDS SHOULD CONFINE ANY LINGERING LAKE EFFECT TO THE OPEN WATER. HOWEVER...WEAK 295K ISENTROPIC UPGLIDE BEGINS AHEAD OF APPROACHING MINNESOTA LOW. WILL MENTION 30 POPS FOR ALL BUT NORTHEAST LOWER AND EASTERN UPPER WHICH ARE TOO FAR REMOVED FROM ASCENT REGION. WENT SLIGHTLY WARMER THAN WARMEST MET GUIDANCE GIVEN EXPECTED MOSTLY CLOUDY SKY CONDITIONS...WITH READINGS FALLING INTO THE LOW TO MID 30S. EXPECT PRECIPITATION TO REMAIN ALL RAIN TONIGHT WITH >1.5KFT SURFACE MELTING LAYER AND +2C WARM TONGUE AT 950MB. SATURDAY...MINNESOTA LOW PRESSURE WEAKENS AS IT CROSSES THE NORTHERN LAKES...LAYING OUT A TRAILING WIND SHIFT LINE/COLD FRONT FROM NORTHERN MICHIGAN INTO THE CENTRAL PLAINS. INTERMOUNTAIN SHORTWAVE AND JET STREAK ROUND BASE OF TROUGH...INITIATING SECONDARY CYCLOGENESIS ALONG QUASI-STATIONARY FRONT OVER MISSOURI. SYSTEM FORECASTED TO GRADUALLY STRENGTHEN AND MOVE NORTHEAST UP FRONT...INCREASING WAA/295K ISENTROPIC UPGLIDE OVER THE UPPER MIDWEST AND GREAT LAKES REGION. BY 00Z SUNDAY...GFS SLIGHTLY FASTER AND HAS LOW POSITIONED OVER SOUTHERN LAKE MICHIGAN WHILE NAM-WRF HAS LOW OVER NORTHERN ILLINOIS. CORRESPONDING QPF FIELDS ALSO INDICATIVE OF INDIVIDUAL SOLUTIONS...WITH GFS OVERSPREADING MEASURABLE RAINFALL OVER ALL AREAS SOUTH OF M-32 BY LATE EVENING WHILE NAM-WRF HAS BEST CHANCE CONFINED TO SOUTHWEST ZONES OF FORECAST AREA. TENDED TO TAKE A BLENDED SOLUTION...INTRODUCING CHANCE POPS ALL AREAS DURING THE MORNING WITH HIGH CHANCE POPS SOUTH ZONES DURING THE AFTERNOON. OVERALL MOISTURE TRANSPORTATION FROM THE GULF RATHER LIMITED AS SPEED OF SYSTEM PREVENTS APPRECIABLE RETURN FLOW. HOWEVER...PERSISTENT ISENTROPIC ASCENT AND DYNAMICS OF SYSTEM SHOULD PROMOTE SHOWER DEVELOPMENT. HIGH TEMPERATURES WILL REMAIN BELOW SEASONAL NORMALS WITH READINGS IN THE MID 40S TO LOW 50S. MSB .LATER PERIODS...MODELS CONTINUE TO HAVE THEIR DIFFICULTY WITH THE DEVELOPING STORM SYSTEM OVER THE GREAT PLAINS THAT WILL TRACK ACROSS THE GREAT LAKES SATURDAY NIGHT INTO SUNDAY. ALTHOUGH SLOWER TRENDS CONTINUE WITH THE GFS/NAM...TIMING DIFFERENCES REMAIN WITH THE NAM/UKMET ON THE SLOWER SIDE...AND THE SREF/GFS IN THE FASTER CAMP (PER HPC DIAGNOSTIC DISCUSSION). HAVE TAKEN A COMPROMISE WITH THIS SYSTEM...BUT NOT SOLD AS MUCH WITH THE NAM SOLUTION...BECAUSE OF THE DIFFERENCES IN LOCATIONS BETWEEN THE LOW PRESSURE CENTER...AND THE UPPER LEVEL DIVERGENCE FIELDS. THIS DIFFERENCE WILL HAVE AN IMPACT ON TIMING THE CHANGE OVER FROM RAIN TO SNOW...WHICH IS QUITE PROBLEMATIC AT THIS POINT. THE COLDER AIR FILTERING IN BEHIND THE LOW WILL BE COLD ENOUGH TO SNOW ON MONDAY AND TUESDAY...BEFORE THE UPPER LEVEL LOW FINALLY KICKS OUT OF THE AREA ON WEDNESDAY. SATURDAY NIGHT INTO SUNDAY...THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONTAL BOUNDARY AND PASS ACROSS SOUTHERN AND CENTRAL LOWER MICHIGAN THROUGH THIS PERIOD. WITH THE ONGOING TIMING ISSUES STILL NEEDING TO BE RESOLVED...WHICH WILL GREATLY AFFECT THE DETAILS OF THIS SYSTEM (EG. PRECIP TYPE)...HAVE MORE OR LESS BROAD BRUSHED THINGS. ALTHOUGH MODELS HAVE TRENDED SLOWER OVER THE LAST FEW RUNS AS A WHOLE...NAM IS SLOWER THAN THE GFS. BOTH MODELS SHOW 290K ISENTROPIC LIFT WITH CONDENSATION PRESSURE DEFICITS WELL LESS THAN 10MB OVERSPREADING THE REGION AHEAD OF THE SYSTEM SATURDAY NIGHT. HOW FAR NORTH DEPENDS ON THE MODEL (WITH THE SLOWER SOLUTION ALLOWING THE ISENTROPIC LIFT TO MOVE FARTHER NORTH). THEN THE LOW WILL PASS ACROSS SOUTHERN LOWER AND APPROACH THE THUMB BY THE 12Z TO 15Z RANGE. TO THE NORTH OF THE LOW TRACK...Q-VECTOR CONVERGENCE AND PLENTY OF 850-700MB FGEN FORCING WILL ALLOW WIDESPREAD PRECIP TO FALL. SO BY TAKING A COMPROMISE...HAVE GONE LIKELY SOUTH OF A TVC TO APN LINE AND CHANCE TO THE NORTH. PRECIP TYPE IS ANOTHER CONCERN SINCE THE SLOWER SOLUTION WILL ALLOW WARMER AIR TO ADVANCE FARTHER NORTH. MODEL SOUNDINGS SHOW PRECIPITATION WILL START OUT AS ALL RAIN SOUTH OF THE STRAITS WITH AN ABOVE 0C WARM LAYER OF 3K-4KFT ABOVE THE SURFACE (KEPT A CHANCE OF SNOW ACROSS EASTERN UPPER). THEN AS COLD ADVECTION SETS IN BEHIND THE LOW...850MB TEMPS COOL IN THE -2C TO -4C (DELTA T'S 13-15C) OVER LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN AS WINDS TURN TO THE NORTH. WITH COOLING TEMPS...HAVE MENTIONED A CHANCE OF SNOW ACROSS PORTIONS OF NW LOWER FROM 06-12Z. COLD ADVECTION CONTINUES TO TAKE PLACE ON SUNDAY ACROSS THE ENTIRE CWA...AND HAVE KEPT A CHANCE FOR RAIN AND SNOW PRESENT AS THE LOW CROSSES LAKE HURON. PLENTY OF CLOUD COVER AND MOISTURE WILL REMAIN BEHIND THE LOW SO SHOWERS/DRIZZLE MIXED WITH SNOW APPEARS GOOD. SUNDAY NIGHT INTO MONDAY...THE CORE OF THE UPPER LEVEL LOW OVER ONTARIO WILL GRADUALLY DROP SOUTHWARD AND ALLOW SHORTWAVES TO SWEEP ACROSS THE WESTERN GREAT LAKES. 850MB TEMPERATURES WILL CONTINUE TO FALL TO -6C TO -7C RANGE WHILE 850-700MB RH VALUES REMAIN GREATER THAN 70 PCT. WITH WINDS WNW-NW AND INVERSION HEIGHTS INCREASING FROM ABOUT 4KFT BY 00Z MON TO 7KFT BY 00Z TUE...SNOW SHOWERS ARE THE WAY TO GO RIGHT NOW SUNDAY NIGHT. WILL NOT GO LIKELY AT THIS TIME...BUT MONDAY LOOKS SNOWY AT THE MOMENT ACROSS HIGHER ELEVATIONS (MIXED WITH RAIN ALONG THE COASTS ON MONDAY). TUESDAY THROUGH THURSDAY...OVERALL PATTERN UNDERGOES MAJOR CHANGES OVER THIS PERIOD FROM COLDER AND UNSETTLED TO A MORE WARMER AND TRANQUIL REGIME. MODEL CONSENSUS SHOWS RIDGING BREAKING DOWN OVER THE NORTHERN ATLANTIC AS THE STAGNANT UPPER LEVEL LOW OVER THE GREAT LAKES FINALLY LIFTS TO THE NE OVER THE CANADIAN MARITIMES TO THE SOUTHERN TIP OF GREENLAND BY 00Z FRIDAY. SO FAR THE START OF THE PERIOD...LINGERING UPPER AND LOWER LEVEL CYCLONIC FLOW WILL REMAIN IN PLACE WITH 1000-500MB THICKNESSES AROUND 530 DAM AND 850MB TEMPS IN THE -5C TO -7C RANGE ON TUESDAY AND TUESDAY NIGHT. WILL THEREFORE KEEP THE THREAT OF SNOW SHOWERS IN PLACE ACROSS THE INTERIOR OF THE CWA...AND A MIX ALONG THE GREAT LAKES COASTLINES. HIGH PRESSURE RIDGE AXIS SETTLES OVER THE AREA ON WEDNESDAY AND 850MB TEMPERATURES MODERATE AS THE DAY WEARS ON. WILL REMOVE POPS WEDNESDAY ONWARD WITH THE UPPER LEVEL FLOW BECOMING MORE ZONAL AND HIGH PRESSURE AT THE SURFACE...ACCORDING TO THE NCEP ENSEMBLE AND GFS. FLATTEN RIDGING HANGS ON FOR THE REMAINDER OF THE WEEK. MODELS SHOW A LARGE TROUGH DIGGING OVER THE WESTERN CONUS...WHOSE AMPLITUDE IS QUITE UNCERTAIN AT THIS TIME. THE AMPLITUDE OF THIS TROUGH WILL LARGELY DETERMINE HOW MUCH RIDGING WE SEE OVER THE GREAT LAKES...AND HOW MUCH WE WARM UP. MPC && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 215 PM PDT FRI OCT 20 2006 .SYNOPSIS...AN UPPER LEVEL RIDGE WILL BUILD INTO THE PACIFIC NORTHWEST STARTING TONIGHT. THE BENIGN RIDGE PATTERN WILL PERSIST UNTIL EARLY NEXT WEEK AS A COOL TROUGH DROPS IN FROM THE NORTHWEST. && .DISCUSSION... TONIGHT THROUGH SATURDAY NIGHT...WITH THE POLAR JET AXIS CENTERED RIGHT ALONG THE EASTERN FLANK OF THE CWA...SOME UPPER DIVERGENCE HAS HELPED MODEST MUCAPES AND MID-LEVEL INSTABILITY MANIFESTED AS NEGATIVE THETA-E LAPSE RATES IN THE 700-500 MB LAYER ON THE GFS AND RUC TO ALLOW FOR SOME CONTINUED CUMULUS DEVELOPMENT GENERALLY OVER THE IDAHO PANHANDLE...AND SHOSHONE COUNTY IN PARTICULAR. OUTSIDE OF THAT...A FEW TERRAIN BASED CUMULUS HAVE DEVELOPED NEAR THE CASCADE CREST AND OKANOGAN HIGHLANDS...NEITHER OF WHICH WERE UNANTICIPATED. SHOWER ACTIVITY DIED OFF EARLY THIS MORNING...AND CUMULUS DEVELOPMENT SHOULD BE ON THE WANE SHORTLY WITH THE LOSS OF DAYTIME HEATING...WEAKENING OF MID-LEVEL THETA-E LAPSE RATES...AND THE LOSS OF WEAK ISENTROPIC ASCENT IN THE SOUTHEASTERN PORTION OF THE CWA IN THE 290-300K LAYER. A CLEAR NIGHT SEEMS TO BE IN STORE FOR THE VAST MAJORITY OF THE CWA WITH SIGNIFICANTLY LIGHTER WINDS THAN LAST NIGHT DUE TO A SLACKENING IN THE PRESSURE GRADIENT ACROSS THE CWA. ADDITIONALLY...WITH CLEARING SKIES AND INVERSIONS SETTING UP OVERNIGHT...ALONG WITH SIGNIFICANTLY LESS AVAILABLE MOMENTUM ALOFT...BELIEVE DOWNWARD MIXING OF STRONGER FLOW ALOFT WILL BE GREATLY REDUCED TONIGHT. THAT BEING SAID...WITH STILL WEAK COLD ADVECTION OCCURRING THROUGH THE BASIN AND DOWN THE OKANOGAN VALLEY...BELIEVE WINDS WILL STAY UP JUST ENOUGH TO REDUCE FOG CHANCES. ELSEWHERE...SOME PATCHY FOG IS POSSIBLE BY MORNING UNDERNEATH A WEAK INVERSION THAT WILL SET UP OVERNIGHT...FUELED BY THE RECENT RAINS AND GOOD SOIL MOISTURE CONTENT. GOING FORWARD...RIDGE BUILDS INTO THE AREA IN EARNEST TOMORROW AND GOOD INSOLATION WILL LIKELY WIPEOUT THE MORNING FOG THAT DOES DEVELOP RATHER QUICKLY. TEMPERATURES AT 850 MB WILL BE SLOW TO RESPOND WITH NORTHEASTERLY FLOW...SO TEMPERATURES WILL STICK NEAR TO TODAY'S HIGHS. SATURDAY NIGHT LOOKS TO BE ANOTHER VERY GOOD RADIATIONAL COOLING NIGHT...WITH TEMPERATURES DROPPING BELOW FREEZING FOR A LARGE PORTION OF THE CWA. GFS AND NAM SOUNDINGS INDICATE A STRONG INVERSION SETS UP OVERNIGHT...WITH DEWPOINT DEPRESSIONS OF ONLY A COUPLE DEGREES...HOLDING LOW LEVEL RH VALUES UP OVERNIGHT BELOW THE INVERSION. BELIEVE THAT FOG WILL LIKELY FORM AGAIN IN LOWER ELEVATIONS NEARLY CWA-WIDE GIVEN LOWER FORECAST WINDS...STRONG INVERSIONS...STILL HIGH SOIL MOISTURE...AND LITTLE IF ANY CHANCE OF ANY HIGHER MOMENTUM AIR MIXING DOWN. /FRIES SUNDAY THROUGH MONDAY...MODELS ARE IN BETTER AGREEMENT TODAY THROUGH THIS FORECAST PERIOD. HIGH PRESSURE OVER THE REGION ON SUNDAY WILL BRING ONE MORE DAY OF MOSTLY SUNNY SKIES AND SEASONAL TEMPERATURES. THE MORNING WILL START OUT ON THE COOL SIDE WITH AREAS OF RADIATIONAL FOG. BY SUNDAY NIGHT INTO MONDAY THE NEXT WEAK SHORT WAVE DISTURBANCE WILL TRACK THROUGH THE NORTHERN ZONES AND CRASH INTO THE RIDGE. NOT A LOT OF MOISTURE OR DYNAMICS WITH THIS SHORT WAVE BUT SOME LOW END POPS WERE KEPT IN THE NORTHERN HIGHLANDS TO COVER. THIS DISTURBANCE WILL ACT TO BREAK DOWN THE RIDGE AND OPEN THE DOOR FOR A MORE SIGNIFICANT STORM SYSTEM LATER IN THE FORECAST PERIOD. /TOBIN MONDAY NIGHT THROUGH FRIDAY...GFS/ECMWF/CANADIAN MODELS HAVE COME INTO GOOD AGREEMENT FOR THE EXTENDED PERIOD. AN UNSETTLED PERIOD IS EXPECTED TUESDAY AND WEDNESDAY AS AN UPPER LEVEL TROUGH SWINGS THROUGH THE REGION. DOWNSLOPE FLOW OFF THE CASCADES SHOULD LIMIT PRECIPITATION AMOUNTS OVER THE LOWER ELEVATIONS...WHILE THE CASCADE CREST...BLUE MOUNTAINS...CAMAS PRAIRIE...AND IDAHO PANHANDLE WILL SEE UPSLOPE FLOW WITH HIGHER PRECIPITATION CHANCES. WITH 850MB TEMPERATURES DROPPING TO NEAR ZERO...SNOW LEVELS WILL ALSO DROP DOWN TO NEAR 4500-5000 FEET DURING THE DAY AND 3000- 4000 FEET AT NIGHT. ON THURSDAY AND FRIDAY UPPER LEVEL HIGH PRESSURE WILL NOSE TOWARDS THE AREA. GFS/ECMWF SHOW PRESSURE GRADIENTS LESSENING DURING THIS PERIOD IMPLYING LITTLE IN THE WAY OF LOW LEVEL MIXING AS TEMPERATURE INVERSIONS STRENGTHEN DURING THE NIGHT TIME HOURS. THUS...WARM UP ASSOCIATED WITH THE RIDGE SHOULD BE SLOW IN THE LOWEST ELEVATIONS...WITH A STRONGER WARMING TREND MORE LIKELY IN THE MOUNTAINS. JW && .AVIATION...PRIMARILY VFR CONDITIONS ARE EXPECTED TO PERSIST THRU 18Z SAT...ALTHOUGH THERE COULD BE LOCAL IFR CONDITIONS FROM FOG OVERNIGHT INTO SATURDAY MORNING GENERALLY NORTH OF KGEG. /FRIES && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 33 56 31 59 32 60 / 0 0 0 0 10 10 COEUR D'ALENE 32 56 30 58 31 59 / 0 0 0 0 10 10 PULLMAN 34 56 31 58 32 59 / 0 0 0 0 10 10 LEWISTON 38 59 36 63 37 64 / 0 0 0 0 10 10 COLVILLE 31 55 31 56 29 57 / 0 0 0 0 10 10 SANDPOINT 31 53 29 54 28 55 / 0 0 0 0 10 10 KELLOGG 31 55 29 57 30 58 / 0 0 0 0 10 10 MOSES LAKE 33 64 33 65 34 66 / 0 0 0 0 10 10 WENATCHEE 41 64 37 65 38 66 / 0 0 0 0 10 10 OMAK 35 62 35 63 31 64 / 0 0 0 0 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa