AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PUEBLO CO 717 AM MDT SUN MAR 9 2008 .UPDATED... CANCELLED THE FINAL PORTION OF THE SNOW ADVISORY ACROSS THE WET MOUNTAINS...SANGRE DE CRISTO MOUNTAINS...AND SOUTHERN FOOTHILLS BASED ON DECREASING COVERAGE AND INTENSITY OF SNOWFALL PER PUB RADAR DATA. && .PREV DISCUSSION... /ISSUED 601 AM MDT SUN MAR 9 2008/ UPDATE... (THIS MORNING) SNOW HAS BEEN QUICKLY WANING ACROSS CHAFFEE AND FREMONT COUNTY EARLY THIS MORNING. THUS AS ANTICIPATED IN DISCUSSION BELOW...HAVE BEGUN THE PROCESS OF PARING OUT NORTHERN SECTIONS OF THE ADVISORY AREA. SHORT TERM... (TODAY AND TONIGHT) UPPER LOW BACK OVER NRN AZ/NW NM WILL CONTINUE TO DROP SOUTHEASTWARD INTO EXTREME SOUTHERN NM BY 00Z MON. CURRENT RADAR INDICATES SOME FAIRLY WIDESPREAD PRECIPITATION ECHOES ALONG THE EASTERN SLOPES OF THE SE MTS...MAINLY WETS...SANGRES...AND THE ARKANSAS RIVER VALLEY OF FREMONT COUNTY. MYP HAS BEEN REPORTING +SN OFF AND ON...AND WEB CAMS FROM UP THAT WAY SUGGEST A COUPLE INCHES OR SO MAY HAVE ACCUMULATED SINCE AROUND MIDNIGHT. OVERALL...SYSTEM NOT THAT IMPRESSIVE IN SATELLITE LOOPS. BEST DYNAMICS/ISENTROPIC LIFT IS OCCURRING NOW THROUGH AROUND 15Z...THEN IT WANES QUICKLY THROUGH THE LATE MORNING AS THE SYSTEM CONTINUES TO DROP SOUTHWARD. DEFORMATION BAND APPEARS PRETTY FRAGMENTED AND ILL DEFINED. WILL MAINTAIN THE SNOW ADVISORY FOR MOST AREAS...THOUGH WILL BEGIN TO SHAVE OFF SOME OF THE NORTHERN SECTIONS OF LAKE AND EASTERN CHAFFEE COUNTIES. H7 WINDS DON`T APPEAR ALL THAT STRONG IN EITHER MODEL NOW...NAM OR GFS...SO DON`T THINK WESTERN SECTIONS OF THE SAN LUIS VALLEY WILL RECEIVE MUCH IN THE WAY OF HEAVY SNOW...SO WILL ALSO REMOVE THE ADVISORY FOR ZONE 65. FOR THE REMAINDER OF THE ADVISORY AREA...TOTAL ACCUMULATIONS OF 3 TO 8 INCHES CAN BE EXPECTED...WITH THE HEAVIEST ACCUMS ALONG THE EAST SLOPES OF THE WETS AND SANGRES. SNOW WILL GRADUALLY END BY THIS AFTERNOON FOR MOST AREAS AS WEAK EASTERLY UPSLOPE FLOW BECOMES MORE SOUTHWESTERLY. LEE TROF REDEVELOPS TOWARDS DAWN...AND H7 TEMPS BEHIND THIS SYSTEM ARE NOT ALL THAT COLD. MIN TEMPS MAY BE HIT AROUND/BEFORE MIDNIGHT...WITH WESTERLY DRAINAGE FLOW KICKING IN ACROSS THE LOWER EASTERN SLOPES AFTER 06Z CAUSING TEMPS TO STAY STEADY...OR EVEN WARM SLIGHTLY. -KT LONG TERM... (MONDAY THROUGH SATURDAY) ..ACTIVE WEATHER PATTERN TO CONTINUE THIS WEEK... MONDAY...INTERESTING LITTLE WEATHER FEATURE TO DROP SOUTHWARD ON THE BACKSIDE OF THE WEATHER SYSTEM CURRENTLY MOVING THROUGH THE GREAT BASIN. THE WEATHER FEATURE...UPPER LEVEL JET STREAK AND ASSOCIATED LOW/SHORTWAVE TROUGH...IS CURRENTLY OVER WESTERN MT PER WATER VAPOR AND RUC MODEL UPPER AIR ANALYSES. GFS/ECMWF HAS THIS FEATURE DROPPING THROUGH WESTERN CO DURING MONDAY AFTERNOON. NAM- WRF KIND OF HAS THIS FEATURE...BUT NOT PRINTING OUT MUCH IN THE WAY OF QPF. WEATHER FEATURE SHOULD BE MOVING THROUGH THE CENTRAL ROCKIES DURING PEAK HEATING AND INSTABILITY...MIDLEVEL LAPSE RATE OF 7-8 C/KM WOULD SUPPORT AT LEAST A SMALL CHANCE FOR CONVECTIVE PRECIPITATION OVER THE MOUNTAINS/HIGH VALLEYS. THE CURRENT FORECAST HAS SOMETHING TO THIS EXTENT...BUT POPS MIGHT NEED TO BE BUMPED UP A LITTLE OVER THE MOUNTAINS/HIGH VALLEYS IF FUTURE MODELS CONTINUE THIS TREND. TUESDAY THROUGH SATURDAY...OVERALL A PROGRESSIVE WESTERLY FLOW PATTERN APPEARS TO BE TAKING SHAPE WITH WEATHER FEATURES MOVING RAPIDLY THROUGH THE CENTRAL ROCKIES. IN GENERAL...TEMPERATURES ARE FORECAST TO BE AT OR SLIGHTLY ABOVE MARCH AVERAGE READINGS. THE BETTER CHANCE FOR PRECIPITATION SHOULD BE ACROSS THE MOUNTAINS... ESPECIALLY THE CONTINENTAL DIVIDE WEDNESDAY AND AGAIN FRIDAY AND SATURDAY. POTENTIAL EXISTS FOR MORE SNOWFALL ACROSS THE CONTINENTAL DIVIDE FRIDAY AND SATURDAY. BREEZY/WINDY CONDITIONS WILL BE LIKELY TUESDAY THROUGH SATURDAY. 17 AVIATION... MVFR/VFR CIGS EXPECTED ACROSS KCOS/KPUB TAF SITES THROUGH THE MORNING...WITH CLEARING SKIES BY LATE AFTERNOON AND EVENING. FOR THE SOUTHERN MTS/FOOTHILLS/HIGH VALLEYS...WIDESPREAD SNOW SHOWERS WILL CONTINUE THROUGH THE MORNING WITH IFR TO LIFR CIGS ALONG THE EASTERN SLOPES AND HIGHER TERRAIN WHERE EASTERLY UPSLOPE FLOW WILL CONTINUE. KALS MAY SEE SOME MVFR TO BRIEF IFR UNDER SNOW SHOWERS THROUGH THE MORNING. IMPROVING CONDITIONS EXPECTED FOR ALL OF THE AREA DURING THE AFTERNOON AND EVENING WITH SOME PERSISTENT ISOLATED TO SCATTERED SNOW SHOWERS CONTINUING ALONG THE CONTDVD THROUGH THE EVENING. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 17/17 co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PUEBLO CO 601 AM MDT SUN MAR 9 2008 .UPDATE... (THIS MORNING) SNOW HAS BEEN QUICKLY WANING ACROSS CHAFFEE AND FREMONT COUNTY EARLY THIS MORNING. THUS AS ANTICIPATED IN DISCUSSION BELOW...HAVE BEGUN THE PROCESS OF PARING OUT NORTHERN SECTIONS OF THE ADVISORY AREA. && .SHORT TERM... (TODAY AND TONIGHT) UPPER LOW BACK OVER NRN AZ/NW NM WILL CONTINUE TO DROP SOUTHEASTWARD INTO EXTREME SOUTHERN NM BY 00Z MON. CURRENT RADAR INDICATES SOME FAIRLY WIDESPREAD PRECIPITATION ECHOES ALONG THE EASTERN SLOPES OF THE SE MTS...MAINLY WETS...SANGRES...AND THE ARKANSAS RIVER VALLEY OF FREMONT COUNTY. MYP HAS BEEN REPORTING +SN OFF AND ON...AND WEB CAMS FROM UP THAT WAY SUGGEST A COUPLE INCHES OR SO MAY HAVE ACCUMULATED SINCE AROUND MIDNIGHT. OVERALL...SYSTEM NOT THAT IMPRESSIVE IN SATELLITE LOOPS. BEST DYNAMICS/ISENTROPIC LIFT IS OCCURRING NOW THROUGH AROUND 15Z...THEN IT WANES QUICKLY THROUGH THE LATE MORNING AS THE SYSTEM CONTINUES TO DROP SOUTHWARD. DEFORMATION BAND APPEARS PRETTY FRAGMENTED AND ILL DEFINED. WILL MAINTAIN THE SNOW ADVISORY FOR MOST AREAS...THOUGH WILL BEGIN TO SHAVE OFF SOME OF THE NORTHERN SECTIONS OF LAKE AND EASTERN CHAFFEE COUNTIES. H7 WINDS DON`T APPEAR ALL THAT STRONG IN EITHER MODEL NOW...NAM OR GFS...SO DON`T THINK WESTERN SECTIONS OF THE SAN LUIS VALLEY WILL RECEIVE MUCH IN THE WAY OF HEAVY SNOW...SO WILL ALSO REMOVE THE ADVISORY FOR ZONE 65. FOR THE REMAINDER OF THE ADVISORY AREA...TOTAL ACCUMULATIONS OF 3 TO 8 INCHES CAN BE EXPECTED...WITH THE HEAVIEST ACCUMS ALONG THE EAST SLOPES OF THE WETS AND SANGRES. SNOW WILL GRADUALLY END BY THIS AFTERNOON FOR MOST AREAS AS WEAK EASTERLY UPSLOPE FLOW BECOMES MORE SOUTHWESTERLY. LEE TROF REDEVELOPS TOWARDS DAWN...AND H7 TEMPS BEHIND THIS SYSTEM ARE NOT ALL THAT COLD. MIN TEMPS MAY BE HIT AROUND/BEFORE MIDNIGHT...WITH WESTERLY DRAINAGE FLOW KICKING IN ACROSS THE LOWER EASTERN SLOPES AFTER 06Z CAUSING TEMPS TO STAY STEADY...OR EVEN WARM SLIGHTLY. -KT .LONG TERM... (MONDAY THROUGH SATURDAY) ...ACTIVE WEATHER PATTERN TO CONTINUE THIS WEEK... MONDAY...INTERESTING LITTLE WEATHER FEATURE TO DROP SOUTHWARD ON THE BACKSIDE OF THE WEATHER SYSTEM CURRENTLY MOVING THROUGH THE GREAT BASIN. THE WEATHER FEATURE...UPPER LEVEL JET STREAK AND ASSOCIATED LOW/SHORTWAVE TROUGH...IS CURRENTLY OVER WESTERN MT PER WATER VAPOR AND RUC MODEL UPPER AIR ANALYSES. GFS/ECMWF HAS THIS FEATURE DROPPING THROUGH WESTERN CO DURING MONDAY AFTERNOON. NAM- WRF KIND OF HAS THIS FEATURE...BUT NOT PRINTING OUT MUCH IN THE WAY OF QPF. WEATHER FEATURE SHOULD BE MOVING THROUGH THE CENTRAL ROCKIES DURING PEAK HEATING AND INSTABILITY...MIDLEVEL LAPSE RATE OF 7-8 C/KM WOULD SUPPORT AT LEAST A SMALL CHANCE FOR CONVECTIVE PRECIPITATION OVER THE MOUNTAINS/HIGH VALLEYS. THE CURRENT FORECAST HAS SOMETHING TO THIS EXTENT...BUT POPS MIGHT NEED TO BE BUMPED UP A LITTLE OVER THE MOUNTAINS/HIGH VALLEYS IF FUTURE MODELS CONTINUE THIS TREND. TUESDAY THROUGH SATURDAY...OVERALL A PROGRESSIVE WESTERLY FLOW PATTERN APPEARS TO BE TAKING SHAPE WITH WEATHER FEATURES MOVING RAPIDLY THROUGH THE CENTRAL ROCKIES. IN GENERAL...TEMPERATURES ARE FORECAST TO BE AT OR SLIGHTLY ABOVE MARCH AVERAGE READINGS. THE BETTER CHANCE FOR PRECIPITATION SHOULD BE ACROSS THE MOUNTAINS... ESPECIALLY THE CONTINENTAL DIVIDE WEDNESDAY AND AGAIN FRIDAY AND SATURDAY. POTENTIAL EXISTS FOR MORE SNOWFALL ACROSS THE CONTINENTAL DIVIDE FRIDAY AND SATURDAY. BREEZY/WINDY CONDITIONS WILL BE LIKELY TUESDAY THROUGH SATURDAY. METZE && .AVIATION... MVFR/VFR CIGS EXPECTED ACROSS KCOS/KPUB TAF SITES THROUGH THE MORNING...WITH CLEARING SKIES BY LATE AFTERNOON AND EVENING. FOR THE SOUTHERN MTS/FOOTHILLS/HIGH VALLEYS...WIDESPREAD SNOW SHOWERS WILL CONTINUE THROUGH THE MORNING WITH IFR TO LIFR CIGS ALONG THE EASTERN SLOPES AND HIGHER TERRAIN WHERE EASTERLY UPSLOPE FLOW WILL CONTINUE. KALS MAY SEE SOME MVFR TO BRIEF IFR UNDER SNOW SHOWERS THROUGH THE MORNING. IMPROVING CONDITIONS EXPECTED FOR ALL OF THE AREA DURING THE AFTERNOON AND EVENING WITH SOME PERSISTENT ISOLATED TO SCATTERED SNOW SHOWERS CONTINUING ALONG THE CONTDVD THROUGH THE EVENING. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL NOON MDT TODAY FOR COZ072>075-078>080-087- 088. && $$ 31/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 349 AM MDT SUN MAR 9 2008 .SHORT TERM... (TODAY AND TONIGHT) UPPER LOW BACK OVER NRN AZ/NW NM WILL CONTINUE TO DROP SOUTHEASTWARD INTO EXTREME SOUTHERN NM BY 00Z MON. CURRENT RADAR INDICATES SOME FAIRLY WIDESPREAD PRECIPITATION ECHOES ALONG THE EASTERN SLOPES OF THE SE MTS...MAINLY WETS...SANGRES...AND THE ARKANSAS RIVER VALLEY OF FREMONT COUNTY. MYP HAS BEEN REPORTING +SN OFF AND ON...AND WEB CAMS FROM UP THAT WAY SUGGEST A COUPLE INCHES OR SO MAY HAVE ACCUMULATED SINCE AROUND MIDNIGHT. OVERALL...SYSTEM NOT THAT IMPRESSIVE IN SATELLITE LOOPS. BEST DYNAMICS/ISENTROPIC LIFT IS OCCURRING NOW THROUGH AROUND 15Z...THEN IT WANES QUICKLY THROUGH THE LATE MORNING AS THE SYSTEM CONTINUES TO DROP SOUTHWARD. DEFORMATION BAND APPEARS PRETTY FRAGMENTED AND ILL DEFINED. WILL MAINTAIN THE SNOW ADVISORY FOR MOST AREAS...THOUGH WILL BEGIN TO SHAVE OFF SOME OF THE NORTHERN SECTIONS OF LAKE AND EASTERN CHAFFEE COUNTIES. H7 WINDS DON`T APPEAR ALL THAT STRONG IN EITHER MODEL NOW...NAM OR GFS...SO DON`T THINK WESTERN SECTIONS OF THE SAN LUIS VALLEY WILL RECEIVE MUCH IN THE WAY OF HEAVY SNOW...SO WILL ALSO REMOVE THE ADVISORY FOR ZONE 65. FOR THE REMAINDER OF THE ADVISORY AREA...TOTAL ACCUMULATIONS OF 3 TO 8 INCHES CAN BE EXPECTED...WITH THE HEAVIEST ACCUMS ALONG THE EAST SLOPES OF THE WETS AND SANGRES. SNOW WILL GRADUALLY END BY THIS AFTERNOON FOR MOST AREAS AS WEAK EASTERLY UPSLOPE FLOW BECOMES MORE SOUTHWESTERLY. LEE TROF REDEVELOPS TOWARDS DAWN...AND H7 TEMPS BEHIND THIS SYSTEM ARE NOT ALL THAT COLD. MIN TEMPS MAY BE HIT AROUND/BEFORE MIDNIGHT...WITH WESTERLY DRAINAGE FLOW KICKING IN ACROSS THE LOWER EASTERN SLOPES AFTER 06Z CAUSING TEMPS TO STAY STEADY...OR EVEN WARM SLIGHTLY. -KT .LONG TERM... (MONDAY THROUGH SATURDAY) ...ACTIVE WEATHER PATTERN TO CONTINUE THIS WEEK... MONDAY...INTERESTING LITTLE WEATHER FEATURE TO DROP SOUTHWARD ON THE BACKSIDE OF THE WEATHER SYSTEM CURRENTLY MOVING THROUGH THE GREAT BASIN. THE WEATHER FEATURE...UPPER LEVEL JET STREAK AND ASSOCIATED LOW/SHORTWAVE TROUGH...IS CURRENTLY OVER WESTERN MT PER WATER VAPOR AND RUC MODEL UPPER AIR ANALYSES. GFS/ECMWF HAS THIS FEATURE DROPPING THROUGH WESTERN CO DURING MONDAY AFTERNOON. NAM- WRF KIND OF HAS THIS FEATURE...BUT NOT PRINTING OUT MUCH IN THE WAY OF QPF. WEATHER FEATURE SHOULD BE MOVING THROUGH THE CENTRAL ROCKIES DURING PEAK HEATING AND INSTABILITY...MIDLEVEL LAPSE RATE OF 7-8 C/KM WOULD SUPPORT AT LEAST A SMALL CHANCE FOR CONVECTIVE PRECIPITATION OVER THE MOUNTAINS/HIGH VALLEYS. THE CURRENT FORECAST HAS SOMETHING TO THIS EXTENT...BUT POPS MIGHT NEED TO BE BUMPED UP A LITTLE OVER THE MOUNTAINS/HIGH VALLEYS IF FUTURE MODELS CONTINUE THIS TREND. TUESDAY THROUGH SATURDAY...OVERALL A PROGRESSIVE WESTERLY FLOW PATTERN APPEARS TO BE TAKING SHAPE WITH WEATHER FEATURES MOVING RAPIDLY THROUGH THE CENTRAL ROCKIES. IN GENERAL...TEMPERATURES ARE FORECAST TO BE AT OR SLIGHTLY ABOVE MARCH AVERAGE READINGS. THE BETTER CHANCE FOR PRECIPITATION SHOULD BE ACROSS THE MOUNTAINS... ESPECIALLY THE CONTINENTAL DIVIDE WEDNESDAY AND AGAIN FRIDAY AND SATURDAY. POTENTIAL EXISTS FOR MORE SNOWFALL ACROSS THE CONTINENTAL DIVIDE FRIDAY AND SATURDAY. BREEZY/WINDY CONDITIONS WILL BE LIKELY TUESDAY THROUGH SATURDAY. METZE && .AVIATION... MVFR/VFR CIGS EXPECTED ACROSS KCOS/KPUB TAF SITES THROUGH THE MORNING...WITH CLEARING SKIES BY LATE AFTERNOON AND EVENING. FOR THE SOUTHERN MTS/FOOTHILLS/HIGH VALLEYS...WIDESPREAD SNOW SHOWERS WILL CONTINUE THROUGH THE MORNING WITH IFR TO LIFR CIGS ALONG THE EASTERN SLOPES AND HIGHER TERRAIN WHERE EASTERLY UPSLOPE FLOW WILL CONTINUE. KALS MAY SEE SOME MVFR TO BRIEF IFR UNDER SNOW SHOWERS THROUGH THE MORNING. IMPROVING CONDITIONS EXPECTED FOR ALL OF THE AREA DURING THE AFTERNOON AND EVENING WITH SOME PERSISTENT ISOLATED TO SCATTERED SNOW SHOWERS CONTINUING ALONG THE CONTDVD THROUGH THE EVENING. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL NOON MDT TODAY FOR COZ060>062-072>080-087- 088. && $$ 31/17 co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PADUCAH KY 1212 PM CDT SUN MAR 9 2008 .UPDATE... SENSIBLE WEATHER UPDATE FOR TODAY AND TONIGHT. && .DISCUSSION... COMPARED TO YESTERDAYS RUNS...THE CLOUD COVER IS MUCH SLOWER AND THINNER THAN EXPECTED. WITH THAT IN MIND...SLOWED THE SEWD PROGRESSION OF OPAQUE CLOUD COVER ACROSS THE WFO PAH FORECAST AREA FOR THE REMAINDER OF THIS AFTERNOON AND INTO THE EARLY EVENING. DUE TO AVERAGING TECHNIQUES...TEXT FORECASTS WILL STILL SHOW PARTLY CLOUDY/SUNNY FOR CLOUD TRENDS THIS AFTERNOON. WITH THE SHARPLY DIMINISHED SNOW COVER...EVEN THE TURBULENT MIXING ASSOCIATED WITH THE INCREASED WARM AIR ADVECTION IS RETARDING TIMELY DEVELOPMENT OF CUMULUS THIS AFTERNOON. DESPITE THE SNOW COVER...WARM AIR ADVECTION AND GOOD INSOLATION SHOULD HELP TEMPERATURES OVER SOUTHWESTERN INDIANA AND THE PENNYRILE REGION OF WEST KENTUCKY RECOVER INTO THE LOWER 40S...WITH 50S EXPECTED IN THE SNOW FREE AREAS OF SOUTHEAST MISSOURI...SOUTHERN ILLINOIS AND THE PURCHASE AREA OF WEST KENTUCKY. UTILIZED A BLEND OF SREF/NAM/RUC GUIDANCE FOR MAX TEMPERATURES TODAY...WITH A BLEND OF THE RUC/NAM FOR DEWPOINTS AND WINDS THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 316 AM CDT SUN MAR 9 2008/ DISCUSSION... MAIN FORECAST ISSUES ARE TEMPERATURES AND WEAK SYSTEM MOVING THROUGH SUNDAY NIGHT/MONDAY. TEMPERATURES TODAY WERE BASED ON SEVERAL PARAMETERS...THE LATEST VISIBLE SATELLITE IMAGE TO SEE WHERE SNOW WAS STILL ON THE GROUND...THE PREVIOUS FORECAST...AND A HEDGE TOWARD THE GFS MODEL. SOME OF THE MODEL GUIDANCE IS OUT TO LUNCH...CLEARLY MISSING THE FACT THERE IS SNOW ON THE GROUND. LATEST IR IMAGES AND TIME-HEIGHT CROSS SECTIONS SUGGEST THAT A MID LEVEL CLOUD DECK MAY ALSO PLAY A ROLE ACROSS THE AREA. A MAJORITY OF THE SNOW SHOULD MELT TODAY...BUT IN THE HEAVIER BANDS...THERE STILL MAY BE A LINGERING EFFECT ON MONDAY...SO WILL KEEP TEMPERATURES A BIT LOWER IN THE EAST. TEMPERATURE ADVECTION NOT VERY IMPRESSIVE AHEAD OR BEHIND THE SYSTEM ON MONDAY. SHORTWAVE OF CONCERN CURRENTLY OVER THE UPPER MIDWEST AND IS FORECAST TO REACH THE AREA JUST BEFORE 06Z MONDAY. THE NAM IS WEAKER AND A BIT SLOWER WITH THE SHORTWAVE. LEANED MORE TOWARD THE GFS FOR THIS PART OF THE FORECAST AS IT HAS BEEN A PERSISTENT SIGNAL. THE LATEST RUN HAS THIS SYSTEM A BIT STRONGER...BUT STILL WEAK. NOW RH INCREASES AS THE SYSTEM MOVES THROUGH. WILL THEREFORE BRING THE SLIGHT CHANCE DOWN TO THE TENNESSEE BORDER. BOTH MODELS HAVE THE SYSTEM OUT OF OUR AREA BY NOON MONDAY. WARM UP FINALLY GETS GOING IN EARNEST BY THE MIDDLE OF THE WEEK AS LOW PRESSURE DEVELOPS OUT OVER THE PLAINS AND SOUTHERLY WINDS INCREASE. WILL LIKELY SEE MEX MOS TEMPS IN THE 60S REALIZED WED AFTERNOON. NEXT COLD FRONT AND H50 TROF MOVE IN THU/THU EVENING AND BRING THE NEXT GOOD CHANCE OF SHOWERS WITH IT. RIGHT NOW...ECMWF AND GFS DIFFER ON HOW THE SFC PRESSURE FIELDS EVOLVE...WITH THE ECMWF HAVING MORE OF A CIRCULATION OVER NRN AL/MS WHILE THE GFS HAS MORE OF AN OPEN ELONGATED SFC TROF COMING THROUGH THU. WILL SPLIT THE DIFFERENCE FOR RIGHT NOW. ENOUGH INSTABILITY ALOFT ARRIVES THU AFTERNOON TO WARRANT SLIGHT CHC THUNDERSTORMS...BUT EVEN THE SHOWALTER INDICES STAY ABOVE 0 EXCEPT IN THE MO BOOTHEEL REGION. ALSO...NO APPRECIABLE CONVERGENCE PROGGED ALONG THE FRONT. THUS...SEVERE ASPECT OF THE SYSTEM LOOKS TO BE QUITE LOW AT THIS TIME. THE FRONT WILL SWEEP THROUGH THU NIGHT AND MAINLY SERVE TO BRING US BACK DOWN TO SEASONAL TEMPS FOR EARLY/MID MARCH. WILL STAY CLOSE TO MEX MOS TEMPS IN THE THU/FRI TIME FRAME. NO CHANGES MADE TO THE FORECAST BEYOND FRI. AVIATION... EXPECT VFR CONDITIONS MOST OF THE TAF PERIOD AS WEAK HIGH PRESSURE CONTINUES ACROSS THE REGION. MAY BE SOME VFR CEILINGS IN THE 5-10K FT RANGE...WITH S-SW WINDS 10 MPH DURING THE DAY. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ SHORTL/LONG TERM....SMITH AVIATION...DH ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1104 PM EDT MON MAR 10 2008 .UPDATE... DRY AIRMASS EXISTS ACROSS THE NORTHERN PLAINS INTO THE UPPER GREAT LAKES...AS NOTED BY 00Z SOUNDINGS FROM INL...BIS...MPX AND GRB. EVEN INTO SOUTHERN MANITOBA...THE AIRMASS IS DRY...WITH THE PAS SOUNDING SHOWING DEWPOINT DEPRESSIONS OF 5C OR MORE THROUGHOUT THE TROPOSPHERE. THIS DRY AIRMASS IS LOCATED ON THE SOUTH SIDE OF A 1009MB LOW CURRENTLY MOVING FROM LAKE WINNIPEG INTO NW ONTARIO. NORTH OF THE SFC LOW IN THE COLDER AIR...11-3.9U IMAGERY DEPICTS PLENTY OF LOW CLOUDS...WITH SOME FLURRIES BEING REPORTED AT A FEW SITES. WARM FRONT ASSOCIATED WITH THE LOW EXTENDS SOUTH TO NEAR FARGO. DESPITE ISENTROPIC LIFT ACROSS THIS FRONT ON WESTERLY WINDS...ALONG WITH A FAIRLY POTENT SHRTW ON WATER VAPOR DROPPING DOWN INTO CENTRAL MANITOBA...THE DRY AIRMASS HAS RESTRICTED ANY CLOUD DEVELOPMENT TO JUST A FEW MID CLOUDS. HIGH CLOUDS ARE PRESENT...BUT THESE ARE MAINLY ASSOCIATED WITH MOISTURE COMING FROM THE PACIFIC THROUGH THE UPPER LEVEL FLOW AS SEEN ON WATER VAPOR. 21Z/00Z RUC AND 18Z/00Z NAM SEEM TO BE HANDLING THE MOISTURE AVAILABILITY WITH THIS SYSTEM DROPPING TOWARDS THE CWA TONIGHT AND TOMORROW BETTER THAN THE 12Z/18Z GFS...AND BOTH SUGGEST MAINLY A MID/HIGH CLOUD SCENARIO. PERHAPS THERE IS AN OPPORTUNITY TOMORROW MORNING OVER THE EASTERN CWA TO GENERATE SOME PCPN WITH A LONGER TIME FRAME FOR ISENTROPIC LIFT AND DYNAMICAL FORCING. HOWEVER...THE REST OF TONIGHT LOOKS DRY ACROSS ALL OF THE CWA. LOWERED POPS OVER THE WESTERN CWA TOMORROW MORNING...BUT STILL MAINTAINED THEM FOR THE AFTERNOON AS THE AREA OF LOW CLOUDS NORTH OF THE LOW DROPS SOUTH. NO OTHER CHANGES MADE TO THE FORECAST. && .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW INTO THE WESTERN GREAT LAKES BTWN A TROF OVER ERN CANADA AND A RIDGE OVER WRN NOAM. THE MAIN UPSTREAM FEATURE WAS...A SHORTWAVE TROUGH MOVING FROM NORTHERN ALBERTA INTO SASKATCHEWAN. AT THE SFC...WRLY FLOW WAS INCREASING BTWN HIGH PRES OVER IA/KS/MO AND A TROUGH/FRONT OVER NRN ONTARIO. WITH THE VERY DRY AIRMASS IN PLACE...THE WAA PATTERN INTO UPPER MI WAS ONLY BRINGING AN INCREASE IN HIGH CLOUDS. && .SHORT TERM (TONIGHT AND TUESDAY)... ALTHOUGH RADIATIONAL COOLING MAY ALLOW TEMPS TO FALL OFF THIS EVENING...INCREASING WINDS AND HIGH CLOUDS OVERNIGHT MAY RESULT IN STEADY OR SLOWLY RISING TEMPS FROM MIN VALUES IN THE UPPER TEENS. DOWNSLOPE WSW WINDS WILL ALSO KEEP TEMPS UP OVER PORTIONS OF WEST AND N CNTRL UPPER MI. TUE...MODERATE TO STRONG 700-500 MB QVECTOR CONV ALONG WITH FAIRLY STEEP 700-500 MB LAPSE RATES(AROUND 7 TO 7.5 C/KM) SHOULD BE ENOUGH TO SUPPORT SOME LIGHT SNOW FROM NRN LAKE SUPERIOR INTO THE NE CWA IN SPITE OF THE ANTECEDENT DRY AIR. SO...THE FCST LEANED A BIT MORE TOWARD THE GFS AND CANADIAN REGIONAL GEM WITH LIKELY POPS NE AND CHANCE N CNTRL COMPARED TO THE NAM WHICH DOES NOT PRODUCE ANY PCPN OVER UPPER MI. ANY PCPN SHOULD TAPER OFF IN THE AFTERNOON. MODEL SOUNDINGS AND LOW LEVEL WET-BULB ZERO VALUES WOULD KEEP PCPN AS SNOW. QPF VALUES SUGGEST ANY SNOWFALL WILL BE LESS THAN INCH. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... NW WINDS ON BACK SIDE OF LOW ALONG WITH H85 TEMPS NEAR -10C GOOD ENOUGH FOR CHANCE POPS EARLY TUE NIGHT OVR FAR EAST CWA. OTHERWISE...EXPECT CLEARING SKIES WITH TEMPORARY RIDGING. PWAT MIN MOVING THROUGH SUGGESTS SOME RADIATIONAL COOLING CAN TAKE PLACE. WENT BLO GUIDANCE FOR MIN TEMPS. INCREASING CLOUDS BY MIDDAY WED THEN MIXED PRECIPITATION STILL ON TRACK FOR LATE WEDNESDAY INTO WEDNESDAY EVENING. GFS/ECMWF/CANADIAN IN VERY GOOD AGREEMENT IN TRACKING A NORTHERN STREAM WAVE (A PIECE OF ENERGY EMERGING FM THE STRONGER SHORTWAVE NOW OFFSHORE OF BRITISH COLUMBIA) AND SFC LOW JUST NORTH OF LK SUPERIOR ON THU. DESPITE FACT THAT GFS SHOWS H3 JET STREAKING INTO GREAT LAKES ON WED NIGHT AND THE ECMWF NOT HAVING ANY SUCH FEATURE...MAJORITY OF PCPN THAT OCCURS WED NIGHT IS TIED TO LIFTING ALONG ADVANCING SFC TROUGH AND ISENTROPIC LIFT ON THE 280-290K SFCS. GFS/ECMWF SHOW MUCH BETTER AGREEMENT ON THESE FEATURES ALONG WITH RESULTING QPF. HAVE INCREASED POPS TO LIKELY. PTYPE ALSO SEEMING TO COME INTO SOME AGREEMENT. DEPENDING ON HOW QUICKLY PCPN ARRIVES ON WED POTENTIAL FOR RAIN/SNOW MIX EXISTS INTO EARLY WED EVENING DUE TO RESIDUAL WARM AIR NEAR SFC. 1000-850MB THICKNESSES AND 2M TEMPS FM ECMWF/GFS SUGGEST ANY MIXED RAIN/SNOW WOULD CHANGE TO SNOW BY 06Z THU. COULD SEE UP TO 2 INCHES OF SNOW WITH THE SYSTEM ON WED NIGHT. IN WAKE OF THE SFC TROUGH...DRY AIR SHOULD LIMIT PCPN CHANCES THU. ECMWF/GFS/CANADIAN ALL SHOW A MINIMUM IN QPF IN THE 12 HR PERIOD ENDING AT 00Z FRI. PACIFIC AIR PUSHING IN BEHIND THE TROUGH ALLOWS TEMPS TO WARM INTO THE 30S. SO...IF ANY PCPN DOES OCCUR IT WOULD LIKELY BE IN FORM OF A RAIN/SNOW MIX OR STRICTLY RAIN. PREFERRED LESS AMPLIFIED/WARMER ECMWF/CANADIAN COMPARED TO GFS INTO THE WEEKEND. 12Z GFS IS COMING AROUND TO LESS TROUGHING OVR THE WESTERN GREAT LAKES. H9-H85 TEMPS LOOK MARGINAL FOR LK EFFECT BUT WITH A NORTH WIND AND WEAK CYCLONIC FLOW LINGERING NEED TO KEEP SOME POPS NEAR LAKE SUPERIOR FRI INTO SAT. LK EFFECT ENDS BY SUNDAY AS WINDS BECOME SE WITH SFC RIDGE MOVING ACROSS THE AREA. GFS/ECMWF CONSISTENT ON DEVELOPING SIGNIFICANT STORM SYSTEM OVR NATIONS MID SECTION BY NEXT MONDAY. ECMWF HAS LATCHED ONTO THIS SOLUTION AND BEEN FAIRLY CONSISTENT WITH IT FOR THE LAST FEW DAYS. DETAILS SHOULD BE TAKEN WITH GRAIN OF SALT AT THIS POINT AS THE SHORTWAVES THAT ARE PROGGED TO MORPH INTO THIS LARGE SYSTEM ARE STILL OUT IN THE PACIFIC...NEAR THE GULF OF ALASKA AND EXITING JAPAN. WILL NEED TO WAIT TIL THE UPCOMING WEEKEND WHEN ENERGY REACHES THE WEST COAST BEFORE IT BECOMES SAMPLED BY RAOB NETWORK. IT IS PRETTY INTERESTING THOUGH HOW CONSISTENT THE MODELS HAVE BEEN WITH A SYSTEM THIS FAR OUT IN TIME. STRONG NEGATIVELY TILTED SYSTEMS EJECTING OUT OF THE SOUTHWEST CONUS CAN END UP SLOWER THAN PROGGED SO DECIDED TO KEEP PCPN OUT OF CWA ON SUN NIGHT. FOR NOW...HAVE CHANCE POPS OVER ALL AREAS BY LATE ON DAY 7. TRACK OF STORM SUGGESTS SNOW FOR PTYPE BUT A FARTHER WEST TRACK WOULD RESULT IN LIQUID PCPN. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT VFR CONDITIONS AT BOTH TAF SITES THROUGH TONIGHT AS HIGH PRES RIDGE DOMINATES THE REGION. LOW LEVEL WIND SHEAR SHOULD DEVELOP AS A WRLY LOW LEVEL JET DEVELOPS BETWEEN THE DEPARTING RIDGE AND LOW PRES MOVING INTO NRN ONTARIO. WAA AHEAD OF THE LOW WILL LEAD TO THE CONTINUED LOWERING OF A MID-LVL CLOUD DECK FROM THIS EVENING INTO THE OVERNIGHT HOURS. MVFR CIGS AREA EXPECTED AS A COLD FRONT MOVES INTO UPPER MI TUE MORNING. WHILE SOME MODEL GUIDANCE INDICATED THAT CIGS MAY DROP INTO THE IFR RANGE...THE MODELS SEEM TO BE OVERDOING THE AMOUNT OF MOISTURE CURRENTLY PRESENT UPSTREAM. AS A RESULT...DID NOT INCLUDE IFR CIGS OR PRECIPITATION IN THE FORECAST AT THIS TIME. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SOUTHWEST WINDS TO 30 KT ARE EXPECTED OVER PORTIONS PORTIONS OF LAKE SUPERIOR TONIGHT AHEAD OF THE NEXT APPROACHING LOW PRES TROUGH FROM CANADA. AS THE TROUGH PASSES ON TUESDAY WINDS WILL SHIFT NORTHWEST TO 25 KT OVER THE ERN HALF OF THE LAKE TUESDAY AFTERNOON AND EVENING. WINDS DIE OFF BRIEFLY LATE TUESDAY NIGHT AND EARLY WEDNESDAY BUT THEN INCREASE AGAIN TO 30 KT FROM THE SOUTH-SOUTHEAST WED EVENING AHEAD OF YET ANOTHER CLIPPER LOW WED NIGHT. WINDS SHIFT WEST-NORTHWEST BY FRIDAY BEHIND THE TROUGH PASSAGE AND MAY APPROACH 30 KT OVER THE FAR ERN PORTION OF THE LAKE. DUE TO EXTENSIVE ICE COVERAGE OVER THE WEST HALF OF THE LAKE AND WARMING TEMPERATURES...FREEZING SPRAY WILL NOT BE MUCH OF A FACTOR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...AJ SHORT TERM...JLB LONG TERM...JLA MARINE...JLB AVIATION...TAG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 720 PM EDT MON MAR 10 2008 UPDATED FOR 00Z AVIATION .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW INTO THE WESTERN GREAT LAKES BTWN A TROF OVER ERN CANADA AND A RIDGE OVER WRN NOAM. THE MAIN UPSTREAM FEATURE WAS...A SHORTWAVE TROUGH MOVING FROM NORTHERN ALBERTA INTO SASKATCHEWAN. AT THE SFC...WRLY FLOW WAS INCREASING BTWN HIGH PRES OVER IA/KS/MO AND A TROUGH/FRONT OVER NRN ONTARIO. WITH THE VERY DRY AIRMASS IN PLACE...THE WAA PATTERN INTO UPPER MI WAS ONLY BRINGING AN INCREASE IN HIGH CLOUDS. .SHORT TERM (TONIGHT AND TUESDAY)... ALTHOUGH RADIATIONAL COOLING MAY ALLOW TEMPS TO FALL OFF THIS EVENING...INCREASING WINDS AND HIGH CLOUDS OVERNIGHT MAY RESULT IN STEADY OR SLOWLY RISING TEMPS FROM MIN VALUES IN THE UPPER TEENS. DOWNSLOPE WSW WINDS WILL ALSO KEEP TEMPS UP OVER PORTIONS OF WEST AND N CNTRL UPPER MI. TUE...MODERATE TO STRONG 700-500 MB QVECTOR CONV ALONG WITH FAIRLY STEEP 700-500 MB LAPSE RATES(AROUND 7 TO 7.5 C/KM) SHOULD BE ENOUGH TO SUPPORT SOME LIGHT SNOW FROM NRN LAKE SUPERIOR INTO THE NE CWA IN SPITE OF THE ANTECEDENT DRY AIR. SO...THE FCST LEANED A BIT MORE TOWARD THE GFS AND CANADIAN REGIONAL GEM WITH LIKELY POPS NE AND CHANCE N CNTRL COMPARED TO THE NAM WHICH DOES NOT PRODUCE ANY PCPN OVER UPPER MI. ANY PCPN SHOULD TAPER OFF IN THE AFTERNOON. MODEL SOUNDINGS AND LOW LEVEL WET-BULB ZERO VALUES WOULD KEEP PCPN AS SNOW. QPF VALUES SUGGEST ANY SNOWFALL WILL BE LESS THAN INCH. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... NW WINDS ON BACK SIDE OF LOW ALONG WITH H85 TEMPS NEAR -10C GOOD ENOUGH FOR CHANCE POPS EARLY TUE NIGHT OVR FAR EAST CWA. OTHERWISE...EXPECT CLEARING SKIES WITH TEMPORARY RIDGING. PWAT MIN MOVING THROUGH SUGGESTS SOME RADIATIONAL COOLING CAN TAKE PLACE. WENT BLO GUIDANCE FOR MIN TEMPS. INCREASING CLOUDS BY MIDDAY WED THEN MIXED PRECIPITATION STILL ON TRACK FOR LATE WEDNESDAY INTO WEDNESDAY EVENING. GFS/ECMWF/CANADIAN IN VERY GOOD AGREEMENT IN TRACKING A NORTHERN STREAM WAVE (A PIECE OF ENERGY EMERGING FM THE STRONGER SHORTWAVE NOW OFFSHORE OF BRITISH COLUMBIA) AND SFC LOW JUST NORTH OF LK SUPERIOR ON THU. DESPITE FACT THAT GFS SHOWS H3 JET STREAKING INTO GREAT LAKES ON WED NIGHT AND THE ECMWF NOT HAVING ANY SUCH FEATURE...MAJORITY OF PCPN THAT OCCURS WED NIGHT IS TIED TO LIFTING ALONG ADVANCING SFC TROUGH AND ISENTROPIC LIFT ON THE 280-290K SFCS. GFS/ECMWF SHOW MUCH BETTER AGREEMENT ON THESE FEATURES ALONG WITH RESULTING QPF. HAVE INCREASED POPS TO LIKELY. PTYPE ALSO SEEMING TO COME INTO SOME AGREEMENT. DEPENDING ON HOW QUICKLY PCPN ARRIVES ON WED POTENTIAL FOR RAIN/SNOW MIX EXISTS INTO EARLY WED EVENING DUE TO RESIDUAL WARM AIR NEAR SFC. 1000-850MB THICKNESSES AND 2M TEMPS FM ECMWF/GFS SUGGEST ANY MIXED RAIN/SNOW WOULD CHANGE TO SNOW BY 06Z THU. COULD SEE UP TO 2 INCHES OF SNOW WITH THE SYSTEM ON WED NIGHT. IN WAKE OF THE SFC TROUGH...DRY AIR SHOULD LIMIT PCPN CHANCES THU. ECMWF/GFS/CANADIAN ALL SHOW A MINIMUM IN QPF IN THE 12 HR PERIOD ENDING AT 00Z FRI. PACIFIC AIR PUSHING IN BEHIND THE TROUGH ALLOWS TEMPS TO WARM INTO THE 30S. SO...IF ANY PCPN DOES OCCUR IT WOULD LIKELY BE IN FORM OF A RAIN/SNOW MIX OR STRICTLY RAIN. PREFERRED LESS AMPLIFIED/WARMER ECMWF/CANADIAN COMPARED TO GFS INTO THE WEEKEND. 12Z GFS IS COMING AROUND TO LESS TROUGHING OVR THE WESTERN GREAT LAKES. H9-H85 TEMPS LOOK MARGINAL FOR LK EFFECT BUT WITH A NORTH WIND AND WEAK CYCLONIC FLOW LINGERING NEED TO KEEP SOME POPS NEAR LAKE SUPERIOR FRI INTO SAT. LK EFFECT ENDS BY SUNDAY AS WINDS BECOME SE WITH SFC RIDGE MOVING ACROSS THE AREA. GFS/ECMWF CONSISTENT ON DEVELOPING SIGNIFICANT STORM SYSTEM OVR NATIONS MID SECTION BY NEXT MONDAY. ECMWF HAS LATCHED ONTO THIS SOLUTION AND BEEN FAIRLY CONSISTENT WITH IT FOR THE LAST FEW DAYS. DETAILS SHOULD BE TAKEN WITH GRAIN OF SALT AT THIS POINT AS THE SHORTWAVES THAT ARE PROGGED TO MORPH INTO THIS LARGE SYSTEM ARE STILL OUT IN THE PACIFIC...NEAR THE GULF OF ALASKA AND EXITING JAPAN. WILL NEED TO WAIT TIL THE UPCOMING WEEKEND WHEN ENERGY REACHES THE WEST COAST BEFORE IT BECOMES SAMPLED BY RAOB NETWORK. IT IS PRETTY INTERESTING THOUGH HOW CONSISTENT THE MODELS HAVE BEEN WITH A SYSTEM THIS FAR OUT IN TIME. STRONG NEGATIVELY TILTED SYSTEMS EJECTING OUT OF THE SOUTHWEST CONUS CAN END UP SLOWER THAN PROGGED SO DECIDED TO KEEP PCPN OUT OF CWA ON SUN NIGHT. FOR NOW...HAVE CHANCE POPS OVER ALL AREAS BY LATE ON DAY 7. TRACK OF STORM SUGGESTS SNOW FOR PTYPE BUT A FARTHER WEST TRACK WOULD RESULT IN LIQUID PCPN. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT VFR CONDITIONS AT BOTH TAF SITES THROUGH TONIGHT AS HIGH PRES RIDGE DOMINATES THE REGION. LOW LEVEL WIND SHEAR SHOULD DEVELOP AS A WRLY LOW LEVEL JET DEVELOPS BETWEEN THE DEPARTING RIDGE AND LOW PRES MOVING INTO NRN ONTARIO. WAA AHEAD OF THE LOW WILL LEAD TO THE CONTINUED LOWERING OF A MID-LVL CLOUD DECK FROM THIS EVENING INTO THE OVERNIGHT HOURS. MVFR CIGS AREA EXPECTED AS A COLD FRONT MOVES INTO UPPER MI TUE MORNING. WHILE SOME MODEL GUIDANCE INDICATED THAT CIGS MAY DROP INTO THE IFR RANGE...THE MODELS SEEM TO BE OVERDOING THE AMOUNT OF MOISTURE CURRENTLY PRESENT UPSTREAM. AS A RESULT...DID NOT INCLUDE IFR CIGS OR PRECIPITATION IN THE FORECAST AT THIS TIME. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SOUTHWEST WINDS TO 30 KT ARE EXPECTED OVER PORTIONS PORTIONS OF LAKE SUPERIOR TONIGHT AHEAD OF THE NEXT APPROACHING LOW PRES TROUGH FROM CANADA. AS THE TROUGH PASSES ON TUESDAY WINDS WILL SHIFT NORTHWEST TO 25 KT OVER THE ERN HALF OF THE LAKE TUESDAY AFTERNOON AND EVENING. WINDS DIE OFF BRIEFLY LATE TUESDAY NIGHT AND EARLY WEDNESDAY BUT THEN INCREASE AGAIN TO 30 KT FROM THE SOUTH-SOUTHEAST WED EVENING AHEAD OF YET ANOTHER CLIPPER LOW WED NIGHT. WINDS SHIFT WEST-NORTHWEST BY FRIDAY BEHIND THE TROUGH PASSAGE AND MAY APPROACH 30 KT OVER THE FAR ERN PORTION OF THE LAKE. DUE TO EXTENSIVE ICE COVERAGE OVER THE WEST HALF OF THE LAKE AND WARMING TEMPERATURES...FREEZING SPRAY WILL NOT BE MUCH OF A FACTOR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JLB LONG TERM...JLA MARINE...JLB AVIATION...TAG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 714 PM EDT MON MAR 10 2008 .AVIATION... QUIET CONDITIONS EXPECTED THROUGH MUCH OF THE FORECAST PERIOD. THERE IS THE POSSIBILITY FOR SOME LIGHT FOG AROUND SUNRISE AS LOW-LEVEL MOISTURE INCREASES IN ADVANCE OF AN APPROACHING COLD FRONT. SOUTHWEST WINDS WILL BECOME WELL ESTABLISHED BY SUNRISE AS WELL...AND WILL INCREASE THROUGH THE DAY AS THE FRONT APPROACHES FROM THE NORTHWEST. && .PREV DISCUSSION...ISSUED 340 PM EDT MON MAR 10 2008 SHORT TERM...THIS AFTERNOON AND TONIGHT THE QUALITY OF MOISTURE HAS REMAINED POOR...KEEPING THE SNOW ACTIVITY TO PREDOMINATELY FLURRIES. LATEST TAMDAR SOUNDINGS DEPICT A SATURATED ENVIRONMENT LIMITED TO THE 900-700MB LAYER. THIS AFTERNOONS WATER VAPOR IMAGERY/RUC GUIDANCE EXITS THE SHORTWAVE RESPONSIBLE FOR THE CLOUDS/FLURRIES MOMENTARILY. WILL CARRY NO HYDROMETEORS THIS EVENING AND OVERNIGHT WITH SUBSIDENCE/ANTICYCLONIC VORTICITY ADVECTION AND LOSS OF ANY DIURNALLY ENHANCED LAPSE RATES. TEMPERATURES SHOULD DIP RATHER QUICKLY THIS EVENING AS WINDS REMAIN SUBDUED AND CLOUDS SCATTER QUICKLY. MAINLY GONE A DEGREE OR TWO BELOW GUIDANCE GIVEN FAVORABLE RADIATING CONDITIONS...AROUND 20 FOR MOST AREAS. SHOULD NOT GET QUITE AS COLD TONIGHT SINCE RETURN FLOW WILL DEVELOP ALLOWING FOR SOME WARM AIR ADVECTION. LONG TERM...TUESDAY THROUGH MONDAY THE 12Z MODEL SUITE ARE IN GOOD AGREEMENT WITH RESPECT TO A NORTHERN STREAM WAVE EXPECTED TO MOVE ACROSS THE STATE FROM CENTRAL CANADA TUESDAY AFTERNOON AND EVENING. THE CURRENT WATER VAPOR LOOP ALREADY INDICATES A STRONG UPPER JET OVER WESTERN CANADA. THIS JET IS FORECAST TO DIVE INTO THE WESTERN GREAT LAKES REGION TUESDAY AFTERNOON...STRENGTHENING TO 110 KTS. UPPER DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF THIS JET WILL BE FOCUSED ACROSS SOUTHERN MICHIGAN BY 00Z WED. THE UPPER JET WILL ALSO ALLOW THE MID LEVEL WAVE TO AMPLIFY AS IT CROSSES THE STATE. THE ASSOCIATED SURFACE LOW IS EXPECTED TO PASS NORTH OF THE STATE...WHILE A SURFACE TROUGH AXIS SWINGS THROUGH SE MI BETWEEN 00Z AND 03Z WED. THIS SYSTEM IS EXPECTED TO HAVE GOOD DYNAMICS...WITH A STRONG YET BRIEF SHOT OF DCVA AND UPPER DIVERGENCE. MODEL SOUNDINGS SHOW LACK OF DEEP MOISTURE TO BE THE MAIN LIMITING FACTOR FOR PRECIP. ALL MODEL SOLUTIONS DO HOWEVER SHOW A NARROW RIBBON HIGHER 850-700MB THETA E AIR ADVECTING AHEAD OF THE SURFACE TROUGH. THIS COMBINED WITH THE DYNAMICS WILL WARRANT A LOW CHANCE OF PRECIP BETWEEN THE 21Z TUE AND 03Z WED TIME FRAME. WITH SURFACE TEMPS FORECAST TO RISE INTO THE UPPER 30S/NEAR 40 TUES AFTERNOON...THE BOUNDARY LAYER LOOKS TO BE WARM ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW. MID LEVEL HEIGHTS WILL QUICKLY REBOUND ACROSS THE STATE ON WEDNESDAY IN THE WAKE OF TUESDAY EVENINGS WAVE. SKIES SHOULD ALSO CLEAR OUT BY WEDNESDAY MORNING AS SURFACE HIGH PRESSURE BUILDS ACROSS THE REGION. A BACK DOOR COLD FRONT...ASSOCIATED WITH THE DEPARTING LOW IS FORECAST TO SINK S-SE ACROSS LAKE HURON LATE TUES NIGHT INTO WEDNESDAY...CAUSING 850MB TEMPS TO DROP TO -8 TO -10C OVER THE THUMB REGION BY WED MORNING. THUS...HAVE BACKED OFF WED HIGHS A BIT...CARRYING MAX TEMPS ONLY IN THE LOWER 30S IN THE THUMB TO NEAR 40 WEST OF THE I-75 CORRIDOR. BY WEDNESDAY EVENING THE NEXT WAVE IS ALREADY FORECAST TO BE ADVANCING INTO THE WESTERN GREAT LAKES REGION IN THE VERY PROGRESSIVE NORTHERN STREAM. WHILE THE MAIN SURFACE LOW IS FORECAST TO PASS NORTH OF THE STATE...MODELS DO SHOW AN OCCLUDED FRONT MOVING ACROSS SOUTHERN MI EARLY THURS MORNING. STRONG LOW TO MID LEVEL THETA E ADVECTION LATE WED NIGHT AND THURSDAY MORNING WILL AGAIN WARRANT A CHANCE OF PRECIP. MODELS ARE NOT OVERLY ROBUST WITH THE QPF. HOWEVER GIVEN THE MAGNITUDE OF ISENTROPIC ASCENT...WILL CONTINUE WITH HIGH CHANCE POPS OVERNIGHT WED THROUGH THURS MORNING. A WARMING BOUNDARY LAYER SHOULD SUPPORT MAINLY RAIN AROUND THE DETROIT AREA. LOWER WET BULB ZERO HEIGHTS FARTHER NORTH SHOULD HOWEVER SUPPORT A RAIN/SNOW MIX...POSSIBLY EVEN SOME SLEET. WITH THE FLOW ALOFT TRANSITIONING TO MORE ZONAL ACROSS THE CONUS BY LATE IN THE WEEK...THE AMOUNT OF COLD AIR ADVECTION IS NOT OVERLY IMPRESSIVE IN THE WAKE OF THURSDAYS SYSTEM. THE CURRENT FORECAST HAS HIGHS IN THE LOW TO MID 40S THURS AND FRI WHICH STILL LOOKS REASONABLE. THE NEXT SYSTEM TO MONITOR IS A WAVE IN THE SOUTHERN STREAM FORECAST TO MOVE ACROSS THE OHIO VALLEY ON SATURDAY. THE GFS HAS BEEN TRENDING MORE AMPLIFIED WITH THIS WAVE...AS WELL AS WITH MID LEVEL FGEN OVER THE SOUTHERN GREAT LAKES. THIS MORE AMPLIFIED SOLUTION SOLUTION WOULD BRING COLDER AIR INTO THE STATE ON SATURDAY ALONG WITH THE POTENTIAL FOR ACCUMULATING SNOWFALL ACROSS THE METRO DETROIT AREA AND POINTS SOUTH. THE 12Z ECMWF ALONG WITH SEVERAL GFS ENSEMBLE MEMBERS KEEP THE BULK OF QPF SOUTH OF THE STATE. SO AT THIS TIME A CHANCE OF SNOW ACROSS THE SOUTHERN 1/3RD OF THE CWA SEEMS REASONABLE. MARINE... SURFACE LOW PRESSURE IS FORECAST TO PASS JUST NORTH OF LAKE HURON LATE TUESDAY AFTERNOON AND EVENING...SENDING A COLD FRONT ACROSS THE LAKE AROUND 00Z. SOUTHWESTERLY WINDS WILL INCREASE ACROSS THE LAKES TUES AFTERNOON. MODEL SOUNDINGS ONLY SHOW LIMITED MIXING HEIGHTS OVER LAKE HURON. THE SHALLOW INSTABILITY HOWEVER SHOULD BE ENOUGH TO PROVIDE FREQUENT GUSTS OF 25 TO 30 KNOTS TUES AFTERNOON. MIXING HEIGHTS WILL INCREASE OVER THE LAKES WED NIGHT IN THE WAKE OF THE SURFACE FRONT. THE GRADIENT WILL HOWEVER BEGIN TO WEAKEN...THUS WIND GUSTS SHOULD REMAIN AROUND 25 KNOTS ACROSS THE OPEN WATERS OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION BY WED AFTERNOON...ALLOWING THE WINDS TO BECOME LIGHT AND VARIABLE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... BRISK WIND ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM TUESDAY TO 8 PM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MANN SHORT TERM...CB LONG TERM....SC MARINE.......SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT MON MAR 10 2008 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW INTO THE WESTERN GREAT LAKES BTWN A TROF OVER ERN CANADA AND A RIDGE OVER WRN NOAM. THE MAIN UPSTREAM FEATURE WAS...A SHORTWAVE TROUGH MOVING FROM NORTHERN ALBERTA INTO SASKATCHEWAN. AT THE SFC...WRLY FLOW WAS INCREASING BTWN HIGH PRES OVER IA/KS/MO AND A TROUGH/FRONT OVER NRN ONTARIO. WITH THE VERY DRY AIRMASS IN PLACE...THE WAA PATTERN INTO UPPER MI WAS ONLY BRINGING AN INCREASE IN HIGH CLOUDS. .SHORT TERM (TONIGHT AND TUESDAY)... ALTHOUGH RADIATIONAL COOLING MAY ALLOW TEMPS TO FALL OFF THIS EVENING...INCREASING WINDS AND HIGH CLOUDS OVERNIGHT MAY RESULT IN STEADY OR SLOWLY RISING TEMPS FROM MIN VALUES IN THE UPPER TEENS. DOWNSLOPE WSW WINDS WILL ALSO KEEP TEMPS UP OVER PORTIONS OF WEST AND N CNTRL UPPER MI. TUE...MODERATE TO STRONG 700-500 MB QVECTOR CONV ALONG WITH FAIRLY STEEP 700-500 MB LAPSE RATES(AROUND 7 TO 7.5 C/KM) SHOULD BE ENOUGH TO SUPPORT SOME LIGHT SNOW FROM NRN LAKE SUPERIOR INTO THE NE CWA IN SPITE OF THE ANTECEDENT DRY AIR. SO...THE FCST LEANED A BIT MORE TOWARD THE GFS AND CANADIAN REGIONAL GEM WITH LIKELY POPS NE AND CHANCE N CNTRL COMPARED TO THE NAM WHICH DOES NOT PRODUCE ANY PCPN OVER UPPER MI. ANY PCPN SHOULD TAPER OFF IN THE AFTERNOON. MODEL SOUNDINGS AND LOW LEVEL WET-BULB ZERO VALUES WOULD KEEP PCPN AS SNOW. QPF VALUES SUGGEST ANY SNOWFALL WILL BE LESS THAN INCH. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... NW WINDS ON BACK SIDE OF LOW ALONG WITH H85 TEMPS NEAR -10C GOOD ENOUGH FOR CHANCE POPS EARLY TUE NIGHT OVR FAR EAST CWA. OTHERWISE...EXPECT CLEARING SKIES WITH TEMPORARY RIDGING. PWAT MIN MOVING THROUGH SUGGESTS SOME RADIATIONAL COOLING CAN TAKE PLACE. WENT BLO GUIDANCE FOR MIN TEMPS. INCREASING CLOUDS BY MIDDAY WED THEN MIXED PRECIPITATION STILL ON TRACK FOR LATE WEDNESDAY INTO WEDNESDAY EVENING. GFS/ECMWF/CANADIAN IN VERY GOOD AGREEMENT IN TRACKING A NORTHERN STREAM WAVE (A PIECE OF ENERGY EMERGING FM THE STRONGER SHORTWAVE NOW OFFSHORE OF BRITISH COLUMBIA) AND SFC LOW JUST NORTH OF LK SUPERIOR ON THU. DESPITE FACT THAT GFS SHOWS H3 JET STREAKING INTO GREAT LAKES ON WED NIGHT AND THE ECMWF NOT HAVING ANY SUCH FEATURE...MAJORITY OF PCPN THAT OCCURS WED NIGHT IS TIED TO LIFTING ALONG ADVANCING SFC TROUGH AND ISENTROPIC LIFT ON THE 280-290K SFCS. GFS/ECMWF SHOW MUCH BETTER AGREEMENT ON THESE FEATURES ALONG WITH RESULTING QPF. HAVE INCREASED POPS TO LIKELY. PTYPE ALSO SEEMING TO COME INTO SOME AGREEMENT. DEPENDING ON HOW QUICKLY PCPN ARRIVES ON WED POTENTIAL FOR RAIN/SNOW MIX EXISTS INTO EARLY WED EVENING DUE TO RESIDUAL WARM AIR NEAR SFC. 1000-850MB THICKNESSES AND 2M TEMPS FM ECMWF/GFS SUGGEST ANY MIXED RAIN/SNOW WOULD CHANGE TO SNOW BY 06Z THU. COULD SEE UP TO 2 INCHES OF SNOW WITH THE SYSTEM ON WED NIGHT. IN WAKE OF THE SFC TROUGH...DRY AIR SHOULD LIMIT PCPN CHANCES THU. ECMWF/GFS/CANADIAN ALL SHOW A MINIMUM IN QPF IN THE 12 HR PERIOD ENDING AT 00Z FRI. PACIFIC AIR PUSHING IN BEHIND THE TROUGH ALLOWS TEMPS TO WARM INTO THE 30S. SO...IF ANY PCPN DOES OCCUR IT WOULD LIKELY BE IN FORM OF A RAIN/SNOW MIX OR STRICTLY RAIN. PREFERRED LESS AMPLIFIED/WARMER ECMWF/CANADIAN COMPARED TO GFS INTO THE WEEKEND. 12Z GFS IS COMING AROUND TO LESS TROUGHING OVR THE WESTERN GREAT LAKES. H9-H85 TEMPS LOOK MARGINAL FOR LK EFFECT BUT WITH A NORTH WIND AND WEAK CYCLONIC FLOW LINGERING NEED TO KEEP SOME POPS NEAR LAKE SUPERIOR FRI INTO SAT. LK EFFECT ENDS BY SUNDAY AS WINDS BECOME SE WITH SFC RIDGE MOVING ACROSS THE AREA. GFS/ECMWF CONSISTENT ON DEVELOPING SIGNIFICANT STORM SYSTEM OVR NATIONS MID SECTION BY NEXT MONDAY. ECMWF HAS LATCHED ONTO THIS SOLUTION AND BEEN FAIRLY CONSISTENT WITH IT FOR THE LAST FEW DAYS. DETAILS SHOULD BE TAKEN WITH GRAIN OF SALT AT THIS POINT AS THE SHORTWAVES THAT ARE PROGGED TO MORPH INTO THIS LARGE SYSTEM ARE STILL OUT IN THE PACIFIC...NEAR THE GULF OF ALASKA AND EXITING JAPAN. WILL NEED TO WAIT TIL THE UPCOMING WEEKEND WHEN ENERGY REACHES THE WEST COAST BEFORE IT BECOMES SAMPLED BY RAOB NETWORK. IT IS PRETTY INTERESTING THOUGH HOW CONSISTENT THE MODELS HAVE BEEN WITH A SYSTEM THIS FAR OUT IN TIME. STRONG NEGATIVELY TILTED SYSTEMS EJECTING OUT OF THE SOUTHWEST CONUS CAN END UP SLOWER THAN PROGGED SO DECIDED TO KEEP PCPN OUT OF CWA ON SUN NIGHT. FOR NOW...HAVE CHANCE POPS OVER ALL AREAS BY LATE ON DAY 7. TRACK OF STORM SUGGESTS SNOW FOR PTYPE BUT A FARTHER WEST TRACK WOULD RESULT IN LIQUID PCPN. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT VFR CONDITIONS AT BOTH TAF SITES THROUGH TONIGHT AS HIGH PRES RIDGE DOMINATES THE REGION. LOW LEVEL WIND SHEAR SHOULD DEVELOP AS A WRLY LOW LEVEL JET DEVELOPS BETWEEN THE DEPARTING RIDGE AND LOW PRES MOVING INTO NRN ONTARIO. WAA AHEAD OF THE LOW ILL LEAD TO THE CONTINUED LOWERING OF A MID-LVL CLOUD DECK FROM THIS EVENING INTO THE OVERNIGHT HOURS. MVFR CIGS AREA EXPECTED AS A COLD FRONT MOVES INTO UPPER MI TUE MORNING. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SOUTHWEST WINDS TO 30 KT ARE EXPECTED OVER PORTIONS PORTIONS OF LAKE SUPERIOR TONIGHT AHEAD OF THE NEXT APPROACHING LOW PRES TROUGH FROM CANADA. AS THE TROUGH PASSES ON TUESDAY WINDS WILL SHIFT NORTHWEST TO 25 KT OVER THE ERN HALF OF THE LAKE TUESDAY AFTERNOON AND EVENING. WINDS DIE OFF BRIEFLY LATE TUESDAY NIGHT AND EARLY WEDNESDAY BUT THEN INCREASE AGAIN TO 30 KT FROM THE SOUTH-SOUTHEAST WED EVENING AHEAD OF YET ANOTHER CLIPPER LOW WED NIGHT. WINDS SHIFT WEST-NORTHWEST BY FRIDAY BEHIND THE TROUGH PASSAGE AND MAY APPROACH 30 KT OVER THE FAR ERN PORTION OF THE LAKE. DUE TO EXTENSIVE ICE COVERAGE OVER THE WEST HALF OF THE LAKE AND WARMING TEMPERATURES...FREEZING SPRAY WILL NOT BE MUCH OF A FACTOR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION/MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 340 PM EDT MON MAR 10 2008 .SHORT TERM...THIS AFTERNOON AND TONIGHT THE QUALITY OF MOISTURE HAS REMAINED POOR...KEEPING THE SNOW ACTIVITY TO PREDOMINATELY FLURRIES. LATEST TAMDAR SOUNDINGS DEPICT A SATURATED ENVIRONMENT LIMITED TO THE 900-700MB LAYER. THIS AFTERNOONS WATER VAPOR IMAGERY/RUC GUIDANCE EXITS THE SHORTWAVE RESPONSIBLE FOR THE CLOUDS/FLURRIES MOMENTARILY. WILL CARRY NO HYDROMETEORS THIS EVENING AND OVERNIGHT WITH SUBSIDENCE/ANTICYCLONIC VORTICITY ADVECTION AND LOSS OF ANY DIURNALLY ENHANCED LAPSE RATES. TEMPERATURES SHOULD DIP RATHER QUICKLY THIS EVENING AS WINDS REMAIN SUBDUED AND CLOUDS SCATTER QUICKLY. MAINLY GONE A DEGREE OR TWO BELOW GUIDANCE GIVEN FAVORABLE RADIATING CONDITIONS...AROUND 20 FOR MOST AREAS. SHOULD NOT GET QUITE AS COLD TONIGHT SINCE RETURN FLOW WILL DEVELOP ALLOWING FOR SOME WARM AIR ADVECTION. && .LONG TERM...TUESDAY THROUGH MONDAY THE 12Z MODEL SUITE ARE IN GOOD AGREEMENT WITH RESPECT TO A NORTHERN STREAM WAVE EXPECTED TO MOVE ACROSS THE STATE FROM CENTRAL CANADA TUESDAY AFTERNOON AND EVENING. THE CURRENT WATER VAPOR LOOP ALREADY INDICATES A STRONG UPPER JET OVER WESTERN CANADA. THIS JET IS FORECAST TO DIVE INTO THE WESTERN GREAT LAKES REGION TUESDAY AFTERNOON...STRENGTHENING TO 110 KTS. UPPER DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF THIS JET WILL BE FOCUSED ACROSS SOUTHERN MICHIGAN BY 00Z WED. THE UPPER JET WILL ALSO ALLOW THE MID LEVEL WAVE TO AMPLIFY AS IT CROSSES THE STATE. THE ASSOCIATED SURFACE LOW IS EXPECTED TO PASS NORTH OF THE STATE...WHILE A SURFACE TROUGH AXIS SWINGS THROUGH SE MI BETWEEN 00Z AND 03Z WED. THIS SYSTEM IS EXPECTED TO HAVE GOOD DYNAMICS...WITH A STRONG YET BRIEF SHOT OF DCVA AND UPPER DIVERGENCE. MODEL SOUNDINGS SHOW LACK OF DEEP MOISTURE TO BE THE MAIN LIMITING FACTOR FOR PRECIP. ALL MODEL SOLUTIONS DO HOWEVER SHOW A NARROW RIBBON HIGHER 850-700MB THETA E AIR ADVECTING AHEAD OF THE SURFACE TROUGH. THIS COMBINED WITH THE DYNAMICS WILL WARRANT A LOW CHANCE OF PRECIP BETWEEN THE 21Z TUE AND 03Z WED TIME FRAME. WITH SURFACE TEMPS FORECAST TO RISE INTO THE UPPER 30S/NEAR 40 TUES AFTERNOON...THE BOUNDARY LAYER LOOKS TO BE WARM ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW. MID LEVEL HEIGHTS WILL QUICKLY REBOUND ACROSS THE STATE ON WEDNESDAY IN THE WAKE OF TUESDAY EVENINGS WAVE. SKIES SHOULD ALSO CLEAR OUT BY WEDNESDAY MORNING AS SURFACE HIGH PRESSURE BUILDS ACROSS THE REGION. A BACK DOOR COLD FRONT...ASSOCIATED WITH THE DEPARTING LOW IS FORECAST TO SINK S-SE ACROSS LAKE HURON LATE TUES NIGHT INTO WEDNESDAY...CAUSING 850MB TEMPS TO DROP TO -8 TO -10C OVER THE THUMB REGION BY WED MORNING. THUS...HAVE BACKED OFF WED HIGHS A BIT...CARRYING MAX TEMPS ONLY IN THE LOWER 30S IN THE THUMB TO NEAR 40 WEST OF THE I-75 CORRIDOR. BY WEDNESDAY EVENING THE NEXT WAVE IS ALREADY FORECAST TO BE ADVANCING INTO THE WESTERN GREAT LAKES REGION IN THE VERY PROGRESSIVE NORTHERN STREAM. WHILE THE MAIN SURFACE LOW IS FORECAST TO PASS NORTH OF THE STATE...MODELS DO SHOW AN OCCLUDED FRONT MOVING ACROSS SOUTHERN MI EARLY THURS MORNING. STRONG LOW TO MID LEVEL THETA E ADVECTION LATE WED NIGHT AND THURSDAY MORNING WILL AGAIN WARRANT A CHANCE OF PRECIP. MODELS ARE NOT OVERLY ROBUST WITH THE QPF. HOWEVER GIVEN THE MAGNITUDE OF ISENTROPIC ASCENT...WILL CONTINUE WITH HIGH CHANCE POPS OVERNIGHT WED THROUGH THURS MORNING. A WARMING BOUNDARY LAYER SHOULD SUPPORT MAINLY RAIN AROUND THE DETROIT AREA. LOWER WET BULB ZERO HEIGHTS FARTHER NORTH SHOULD HOWEVER SUPPORT A RAIN/SNOW MIX...POSSIBLY EVEN SOME SLEET. WITH THE FLOW ALOFT TRANSITIONING TO MORE ZONAL ACROSS THE CONUS BY LATE IN THE WEEK...THE AMOUNT OF COLD AIR ADVECTION IS NOT OVERLY IMPRESSIVE IN THE WAKE OF THURSDAYS SYSTEM. THE CURRENT FORECAST HAS HIGHS IN THE LOW TO MID 40S THURS AND FRI WHICH STILL LOOKS REASONABLE. THE NEXT SYSTEM TO MONITOR IS A WAVE IN THE SOUTHERN STREAM FORECAST TO MOVE ACROSS THE OHIO VALLEY ON SATURDAY. THE GFS HAS BEEN TRENDING MORE AMPLIFIED WITH THIS WAVE...AS WELL AS WITH MID LEVEL FGEN OVER THE SOUTHERN GREAT LAKES. THIS MORE AMPLIFIED SOLUTION SOLUTION WOULD BRING COLDER AIR INTO THE STATE ON SATURDAY ALONG WITH THE POTENTIAL FOR ACCUMULATING SNOWFALL ACROSS THE METRO DETROIT AREA AND POINTS SOUTH. THE 12Z ECMWF ALONG WITH SEVERAL GFS ENSEMBLE MEMBERS KEEP THE BULK OF QPF SOUTH OF THE STATE. SO AT THIS TIME A CHANCE OF SNOW ACROSS THE SOUTHERN 1/3RD OF THE CWA SEEMS REASONABLE. && .MARINE... SURFACE LOW PRESSURE IS FORECAST TO PASS JUST NORTH OF LAKE HURON LATE TUESDAY AFTERNOON AND EVENING...SENDING A COLD FRONT ACROSS THE LAKE AROUND 00Z. SOUTHWESTERLY WINDS WILL INCREASE ACROSS THE LAKES TUES AFTERNOON. MODEL SOUNDINGS ONLY SHOW LIMITED MIXING HEIGHTS OVER LAKE HURON. THE SHALLOW INSTABILITY HOWEVER SHOULD BE ENOUGH TO PROVIDE FREQUENT GUSTS OF 25 TO 30 KNOTS TUES AFTERNOON. MIXING HEIGHTS WILL INCREASE OVER THE LAKES WED NIGHT IN THE WAKE OF THE SURFACE FRONT. THE GRADIENT WILL HOWEVER BEGIN TO WEAKEN...THUS WIND GUSTS SHOULD REMAIN AROUND 25 KNOTS ACROSS THE OPEN WATERS OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION BY WED AFTERNOON...ALLOWING THE WINDS TO BECOME LIGHT AND VARIABLE. && .PREV DISCUSSION...ISSUED 144 PM EDT MON MAR 10 2008 AVIATION... OUTSIDE OF SCATTERED SNOW SHOWERS THIS AFTERNOON AT KDET/KDTW AND A TEMPORARY MVFR DECK AT KFNT...TRANQUIL CONDITIONS ARE EXPECTED AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. LIGHT AND VARIABLE SURFACE WINDS WILL SLOWLY TREND WESTERLY THIS EVENING AS RETURN FLOW ARRIVES. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... BRISK WIND ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM TUESDAY TO 8 PM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......SC AVIATION.....CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 140 PM EDT SUN MAR 9 2008 UPDATED AVIATION SECTION FOR 18Z TAFS .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH STRETCHING FROM NEW ENGLAND INTO THE GREAT LAKES REGION. WEAK ENE FLOW AHEAD OF SFC RIDGE OVER ONTARIO LOOKS LIKE IT MAY STILL BE PRODUCING FLURRIES IN DOWNTOWN MQT BUT OTHERWISE DRY CONDITIONS PREVAIL OVER THE REST OF THE CWA. && .DISCUSSION... TODAY...SOME LIGHT LES IS STILL POSSIBLE OVER NCNTRL AREAS FAVORED BY A ENE FLOW AS 850 MB TEMPS ARE AROUND -15C. SOME INCREASE IN LOW LEVEL MOISTURE COMBINED WITH DIURNAL HEATING AND FAIRLY STEEP SFC-850 MB LAPSE RATES OF 7C/KM OR GREATER COULD LEAD TO SOME ISOLATED DIURNAL SNOW SHOWERS OVER THE INTERIOR WEST HALF THIS AFTERNOON AS A WEAK SFC TROF MOVES ACROSS THE AREA. IF THE WRF-ARW QPF VERIFIES...A FEW LOCATIONS UNDER THE HEAVIER SNOW SHOWERS COULD SEE CLOSE TO AN INCH OF SNOW ACCUMULATION USING A 25/1 SNOW/WATER RATIO. TONIGHT...EXPECT CLEARING SKIES AS THE SFC RIDGE FROM ONTARIO DESCENDS OVER THE AREA. WITH LIGHT WINDS AND PCPN WATER AROUND .1 INCH...LOOK FOR IDEAL RADIATIONAL COOLING CONDITIONS. I FOLLOWED THE COLDER GFS BIAS-CORRECTED MOS GUIDANCE WHICH HIGHLIGHTED MIN TEMPS REACHING AROUND -15F IN SOME INTERIOR LOCATIONS OF THE EAST HALF. THESE FCST TEMPS SEEM TOTALLY REASONABLE GIVEN READINGS OBSERVED UPSTREAM THIS MORNING OVER ONTARIO IN PROXIMITY TO THE RIDGE. LOWS COULD EVEN DROP CLOSE TO -10F FOR FAVORED COLD SPOTS IN THE WESTERN INTERIOR BEFORE BOUNDARY LYR WINDS INCREASE OVERNIGHT ON BACK SIDE OF RIDGE AND AHEAD OF NEXT APPROACHING CLIPPER SYSTEM. AFTER A DRY MONDAY WITH TEMPERATURES WARMING BACK TOWARD THE FREEZING MARK IN WSW RETURN FLOW...CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT. MODELS INDICATE TROUGH WILL NOT DIG ENOUGH TO THE SOUTHWEST TO BRING MUCH PCPN INTO UPR MI. BETTER CHANCES FOR PCPN WILL BE OVR LAKE SUPERIOR AND THE ERN FCST AREA CLOSER TO THE TRACK OF THE SHORTWAVE AND ASSOC SFC LOW. KEPT IN A SLIGHT CHC FOR NRN AND ERN TIER COUNTIES MON NIGHT WITH A SLIGHT CHC FOR ALL OF THE CWA ON TUE EXCEPT FOR LOW CHC POPS IN THE EAST. MODELS 1000-850MB THICKNESSES AND FCST SNDGS SUPPORT MORE SNOW AS PREDOMINANT PCPN TYPE MON NIGHT AND TUE. A VERY SHALLOW WARM LAYER NEAR SFC WITH DOWNSLOPING NW WINDS COULD SUPPORT A RAIN/SNOW MIX IN THE FAR SOUTH CENTRAL CWA. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... SCT-BKN LK SC/CU AT EACH SITE. NE-E WINDS KEEP A VERY SMALL CHANCE OF SOME LIGHT SNOW SHOWERS REDEVELOPING AT KSAW...BUT EXPECT MOST OF THE SNOW SHOWERS WILL OCCUR FARTHER INLAND. SKIES WILL CLEAR THIS EVENING AND SHOULD REMAIN CLEAR THROUGH TOMORROW AS HIGH PRESSURE RIDGE IS OVER THE AREA. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... 30.4 INCH HIGH PRESSURE WILL MOVE OVERHEAD LATE THIS AFTERNOON...BEFORE SLOWLY SHIFTING SOUTH TO WESTERN KENTUCKY BY LATE TUESDAY NIGHT. 29.8 INCH LOW PRESSURE FROM MANITOBA MONDAY AFTERNOON...WILL MOVE TO JUST NORTH OF LAKE SUPERIOR TUESDAY MORNING BEFORE SLIDING ACROSS UPPER MICHIGAN TUESDAY AFTERNOON. THIS LOW WILL BRING ABOUT THE NEXT CHANCE OF WINDS AT OR ABOVE 25 KTS. HIGH PRESSURE OF 30.0 INCHES WILL THEN BRIEFLY TAKE OVER TUESDAY NIGHT INTO EARLY WEDNESDAY. A 29.4 INCH LOW WILL MOVE INTO MANITOBA WEDNESDAY AND THROUGH CENTRAL LAKE SUPERIOR ON THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION...JLA MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1241 PM EDT SUN MAR 9 2008 .AVIATION...SCT (VFR CIGS) LAKE CLOUDS WILL BE FOUND AT TVC EARLY IN THE AFTERNOON. OTHERWISE...DRY AIR ACROSS NRN MICHIGAN AND HIGH PRESSURE BUILDING SOUTH OUT OF ONTARIO...WILL LEAD TO VFR CONDITIONS AT TVC/PLN/APN THROUGH THE NEXT 24 HOURS (AND BEYOND)...WITH SOME SCT MID AND HIGH CLOUD MOVING THROUGH. ADAM && .UPDATE...ISSUED AT 1036 AM. VERY DRY BUT COLD AIRMASS REMAINS THE DOMINANT PLAYER ACROSS NORTHERN MICHIGAN THIS MORNING WITH SOLID BELOW ZERO LOW TEMPERATURES AT MANY INLAND AREAS. VERY WEAK SFC TROUGH BISECTING NRN LOWER MICHIGAN WHILE HIGH PRESSURE REBUILDING SOUTHWARD OUT OF ONTARIO. LIGHT NW FLOW OFF LAKE MICHIGAN HAS MANAGED TO GENERATE NARROW AREA OF LAKE SNOW SHOWERS OVERNIGHT AND THIS MORNING... IMPACTING THE SW COUNTIES WITH VSBYS STILL BRIEFLY DIPPING TO AROUND A MILE OR SO AT FKS/CAD. MINOR OVERNIGHT FLUFFY ACCUMULATIONS OF AN INCH OR LESS REPORTED BY SPOTTERS IN THOSE AREAS. FINALLY...MID LEVEL SHEAR AXIS STRETCHES FROM THE PLAINS INTO THE LOWER LAKES GENERATING SOME LIGHT SNOW NEAR CHICAGO AND THROWING HIGH CLOUD COVER INTO NRN MICHIGAN. REST OF TODAY...SIMILAR STORY TO THE LAST FEW DAYS WITH MINOR LAKE EFFECT CLOUDS/PRECIP STARTING OFF THE DAY. HOWEVER...WEAKENING MEAN LOW LEVEL FLOW/A DRY ANTECEDENT AIRMASS OVER THE REGION/DAYTIME MIXING AND MODERATING LOW LEVEL TEMPS SHOULD AGAIN DISSIPATE LAKE STCU AND SNOW SHOWER ACTIVITY BY EARLY AFTERNOON. MID LEVEL SHEAR AXIS TO THE SOUTH WILL CONTINUE TO TOSS THICKER MID-HIGH CLOUD COVER INTO NRN MICHIGAN...MAINLY THE SRN COUNTIES...BUT MAY HAVE ONLY MINIMAL IMPACT ON PERCEIVED SKY CONDITIONS. OVERALL...PLAN ON HAVING SUNNY/MOSTLY SUNNY SKIES FOR MOST AREAS THIS AFTERNOON...PARTLY SUNNY SKIES OVER THE FAR SRN COUNTIES EXCEPT FOR A FEW MORE HOURS OF CLOUDY SKIES/LIGHT SNOW SHOWERS IN THE SW AREAS. BELOW NORMAL AFTERNOON HIGH TEMPS ONCE AGAIN...ALTHOUGH WITH MODERATING LOW LEVEL TEMPS...READINGS EXPECTED TO BREAK INTO THE 20S JUST ABOUT EVERYWHERE. ADAM && .PREV DISCUSSION... /ISSUED 422 AM EDT SUN MAR 9 2008/ DISCUSSION...03Z SURFACE/RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A PERSISTENT AMPLIFIED PATTERN (POSITIVE PNA) ACROSS NORTH AMERICA...WITH THE EASTERN TROUGH CONSISTING OF DUAL 500MB CLOSED LOWS...ONE OVER MINNESOTA...AND THE OTHER OVER UPSTATE NEW YORK. WHILE THE LATTER IS EXITING TO THE NE...SMALLER SCALE SHORTWAVES ROTATING AROUND THE WESTERN UPPER LOW IS SUPPORTING LIGHT SNOW OVER MN AND IA IN A REGION OF MODEST 850-500MB -DIVQ. AIR ACROSS NORTHERN LOWER MICHIGAN IS MUCH DRIER JUDGING BY THE 00Z SOUNDINGS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION THANKS TO LOW LEVEL RIDGING AND A POLAR CONTINENTAL AIRMASS. BECAUSE OF THIS DRY AIR...5-10KFT CLOUD DECK SPREADING EAST ACROSS WI/IL IS HAVING A DEVIL OF A TIME EXTENDING INTO NORTHERN MICHIGAN...RATHER PREFERRING TAKING A MORE SOUTHERN TRACK ACROSS SOUTHERN LOWER. ONLY A FEW LAKE EFFECT SNOW SHOWERS EXIST FROM MANISTEE TO THE LEELANAU PENINSULA AT THIS HOUR. FORECAST CONCERNS ARE MINIMAL FOR THIS TIME OF THE YEAR...AND CONSISTENT OF NUISANT LAKE EFFECT SNOW SHOWER POTENTIAL FIRST...THEN SKY AND TEMPS SECOND OVER THE NEXT 24 HOURS. TODAY...CLOSED LOW OVER MN WILL SHEAR OUT AS IT MIGRATES TOWARDS THE SOUTHERN GREAT LAKES. MID/UPPER LEVEL MOISTURE WILL ROTATE AROUND THE WEAK IOWA SHORTWAVE...PROGGED TO TRACK ACROSS NORTHERN IL/IN/OH...AND SPREAD MID/HIGH CLOUDS ACROSS NORTHERN MICHIGAN...THICKER AS YOU HEAD SOUTH. HOWEVER...VERY DRY AIR CENTERED AROUND 750MB WITH TRAJECTORIES ORIGINATING OUT OF NE ONTARIO AND QUEBEC WILL KEEP THE AREA PRECIP FREE. LAKE EFFECT WILL CONTINUE TO STRUGGLE TO REV UP ESPECIALLY WITH 850MB TEMPS MODERATING FROM -15C TO -13C AND LOW LEVEL WIND FLOW DIMINISHING TO LESS THAN 10KTS BY THIS AFTERNOON. THINK THAT ANY LIGHT SNOW SHOWER AND FLURRY ACTIVITY WILL BE CONFINED TO THE MORNING HOURS FROM THE MANISTEE TO GRAND TRAVERSE BAY CORRIDOR AND BE MOSTLY CONFINED TO THE LAKE SHORES. AS A RESULT...MOST LOCATIONS AWAY FROM THE AFOREMENTIONED AREA WILL SEE PARTLY IF NOT MOSTLY SUNNY SKIES FOR MUCH OF THE DAY. HIGHS IN THE LOW TO MID 20S LOOK FINE. TONIGHT...SHEARED TROUGH AXIS WILL PASS ACROSS THE STATE AND MID/UPPER LEVEL MOISTURE WILL THIN AS A RESULT. DO NOT BELIEVE THESE CLOUDS WILL HAVE MUCH OF AN IMPACT ON TEMPERATURES AND EXPECT ANOTHER EXCELLENT RADIATIONAL COOLING NIGHT IS IN STORE WITH SURFACE HIGH PRESSURE MAINTAINING ITS DOMINANCE ACROSS THE AREA. ONLY POSSIBLE PITFALL IS THAT LOW LEVEL WINDS INCREASE LATE AND SHALLOW INSTABILITY MAY BE ENOUGH FOR A COUPLE FLURRIES ALONG THE LAKE MICHIGAN SHORELINE. BUT THINK DRY AIR (850-700MB RH AROUND 10-20 PCT) AND LAND BREEZE INTERACTION WILL BE ENOUGH TO THWART ANY FLURRY ACTIVITY. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. MONDAY AND MONDAY NIGHT...SHORTWAVE RIDGING MOVES IN ON MONDAY WHILE THE BROAD SURFACE HIGH PRESSURE SHIFTS SOUTH OF THE GREAT LAKES. WEAK WARM ADVECTION WILL ENSUE...ENOUGH TO BUMP UP TEMPS INTO THE LOW 30S. OUTSIDE OF SOME MORNING LAKE CLOUDS AND RESULTING DIURNAL CU (WHICH SHOULD MIX OUT BY EARLY AFTERNOON) AS WEST FLOW STRENGTHENS...MOST AREAS WILL SEE MOSTLY SUNNY SKIES BY MID TO LATE AFTERNOON. MID/UPPER LEVEL CLOUDS WILL BE ON THE INCREASE TOWARDS EVENING AS MOISTURE SPREADS IN AHEAD OF THE NEXT CLIPPER SHORTWAVE. ISENTROPIC ASCENT INCREASES AS WELL...BUT LIMITED MOISTURE BELOW 700MB WILL PREVENT ANY PRECIP FROM REACHING THE GROUND. WITH STRENGTHENING SW FLOW AND INVASION OF WARMER AIR...LOWS WILL BE 15 TO 20 DEGREES WARMER THAN SUNDAY NIGHT. TUESDAY THROUGH THURSDAY...APPROACHING CLIPPER SHORTWAVE PASSES ACROSS LAKE SUPERIOR AND NORTHERN LAKE HURON ON TUESDAY. BEST QG FORCING WILL LIE AHEAD AND TO THE NORTH OF THE SHORTWAVE. GFS IS AN OUTLIER IN THIS REGARD...AND BRINGS A WEAK ASSOCIATED SURFACE LOW AND WIDE SWATH OF PRECIP ACROSS NORTHERN LOWER...WHILE OTHER LEADING MODELS KEEP PRECIP CHANCES NORTH OF THE STRAITS. REGARDLESS...THERMAL PROFILES SUGGEST PRECIP WILL FALL AS ALL SNOW...EVEN IN THE SOUTHERN GFS SOLUTION AND HAVE REMOVED RAIN MENTION. WILL KEEP LOW CHANCE POP ALL THE WAY TO M-55 HOWEVER...BUT WOULDN/T BE SURPRISED IF PRECIP CHANCES ARE REMOVED ACROSS THE SOUTHERN CWA. SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE RETURN TUESDAY NIGHT INTO WEDNESDAY. A CHANCE OF PRECIP THEN ARRIVES WEDNESDAY NIGHT INTO THURSDAY. HIGH TEMPERATURES IN THE UPPER 30S TO LOW 40S OVER THIS PERIOD. MPC && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1036 AM EDT SUN MAR 9 2008 .UPDATE...VERY DRY BUT COLD AIRMASS REMAINS THE DOMINANT PLAYER ACROSS NORTHERN MICHIGAN THIS MORNING WITH SOLID BELOW ZERO LOW TEMPERATURES AT MANY INLAND AREAS. VERY WEAK SFC TROUGH BISECTING NRN LOWER MICHIGAN WHILE HIGH PRESSURE REBUILDING SOUTHWARD OUT OF ONTARIO. LIGHT NW FLOW OFF LAKE MICHIGAN HAS MANAGED TO GENERATE NARROW AREA OF LAKE SNOW SHOWERS OVERNIGHT AND THIS MORNING... IMPACTING THE SW COUNTIES WITH VSBYS STILL BRIEFLY DIPPING TO AROUND A MILE OR SO AT FKS/CAD. MINOR OVERNIGHT FLUFFY ACCUMULATIONS OF AN INCH OR LESS REPORTED BY SPOTTERS IN THOSE AREAS. FINALLY...MID LEVEL SHEAR AXIS STRETCHES FROM THE PLAINS INTO THE LOWER LAKES GENERATING SOME LIGHT SNOW NEAR CHICAGO AND THROWING HIGH CLOUD COVER INTO NRN MICHIGAN. REST OF TODAY...SIMILAR STORY TO THE LAST FEW DAYS WITH MINOR LAKE EFFECT CLOUDS/PRECIP STARTING OFF THE DAY. HOWEVER...WEAKENING MEAN LOW LEVEL FLOW/A DRY ANTECEDENT AIRMASS OVER THE REGION/DAYTIME MIXING AND MODERATING LOW LEVEL TEMPS SHOULD AGAIN DISSIPATE LAKE STCU AND SNOW SHOWER ACTIVITY BY EARLY AFTERNOON. MID LEVEL SHEAR AXIS TO THE SOUTH WILL CONTINUE TO TOSS THICKER MID-HIGH CLOUD COVER INTO NRN MICHIGAN...MAINLY THE SRN COUNTIES...BUT MAY HAVE ONLY MINIMAL IMPACT ON PERCEIVED SKY CONDITIONS. OVERALL...PLAN ON HAVING SUNNY/MOSTLY SUNNY SKIES FOR MOST AREAS THIS AFTERNOON...PARTLY SUNNY SKIES OVER THE FAR SRN COUNTIES EXCEPT FOR A FEW MORE HOURS OF CLOUDY SKIES/LIGHT SNOW SHOWERS IN THE SW AREAS. BELOW NORMAL AFTERNOON HIGH TEMPS ONCE AGAIN...ALTHOUGH WITH MODERATING LOW LEVEL TEMPS...READINGS EXPECTED TO BREAK INTO THE 20S JUST ABOUT EVERYWHERE. ADAM && .AVIATION...ISSUED AT 705 AM. VERY FEW CONCERNS OVER THE NEXT 24 HOURS. LAKE CLOUDS WILL PRODUCE MVFR CIGS AND FLURRIES AT TVC THIS MORNING. WEAKENING WIND FIELDS COMBINED WITH MIXING SHOULD HELP CIGS RISE AND SCATTER BY MIDDAY OR NOT TOO LONG THEREAFTER. OUTSIDE OF POSSIBLE DIURNAL CU AROUND MIDDAY AT APN...ALL TAF SITES SHOULD SEE VFR CONDITIONS PREVAIL. MPC && .PREV DISCUSSION... /ISSUED 422 AM EDT SUN MAR 9 2008/ DISCUSSION...03Z SURFACE/RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A PERSISTENT AMPLIFIED PATTERN (POSITIVE PNA) ACROSS NORTH AMERICA...WITH THE EASTERN TROUGH CONSISTING OF DUAL 500MB CLOSED LOWS...ONE OVER MINNESOTA...AND THE OTHER OVER UPSTATE NEW YORK. WHILE THE LATTER IS EXITING TO THE NE...SMALLER SCALE SHORTWAVES ROTATING AROUND THE WESTERN UPPER LOW IS SUPPORTING LIGHT SNOW OVER MN AND IA IN A REGION OF MODEST 850-500MB -DIVQ. AIR ACROSS NORTHERN LOWER MICHIGAN IS MUCH DRIER JUDGING BY THE 00Z SOUNDINGS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION THANKS TO LOW LEVEL RIDGING AND A POLAR CONTINENTAL AIRMASS. BECAUSE OF THIS DRY AIR...5-10KFT CLOUD DECK SPREADING EAST ACROSS WI/IL IS HAVING A DEVIL OF A TIME EXTENDING INTO NORTHERN MICHIGAN...RATHER PREFERRING TAKING A MORE SOUTHERN TRACK ACROSS SOUTHERN LOWER. ONLY A FEW LAKE EFFECT SNOW SHOWERS EXIST FROM MANISTEE TO THE LEELANAU PENINSULA AT THIS HOUR. FORECAST CONCERNS ARE MINIMAL FOR THIS TIME OF THE YEAR...AND CONSISTENT OF NUISANT LAKE EFFECT SNOW SHOWER POTENTIAL FIRST...THEN SKY AND TEMPS SECOND OVER THE NEXT 24 HOURS. TODAY...CLOSED LOW OVER MN WILL SHEAR OUT AS IT MIGRATES TOWARDS THE SOUTHERN GREAT LAKES. MID/UPPER LEVEL MOISTURE WILL ROTATE AROUND THE WEAK IOWA SHORTWAVE...PROGGED TO TRACK ACROSS NORTHERN IL/IN/OH...AND SPREAD MID/HIGH CLOUDS ACROSS NORTHERN MICHIGAN...THICKER AS YOU HEAD SOUTH. HOWEVER...VERY DRY AIR CENTERED AROUND 750MB WITH TRAJECTORIES ORIGINATING OUT OF NE ONTARIO AND QUEBEC WILL KEEP THE AREA PRECIP FREE. LAKE EFFECT WILL CONTINUE TO STRUGGLE TO REV UP ESPECIALLY WITH 850MB TEMPS MODERATING FROM -15C TO -13C AND LOW LEVEL WIND FLOW DIMINISHING TO LESS THAN 10KTS BY THIS AFTERNOON. THINK THAT ANY LIGHT SNOW SHOWER AND FLURRY ACTIVITY WILL BE CONFINED TO THE MORNING HOURS FROM THE MANISTEE TO GRAND TRAVERSE BAY CORRIDOR AND BE MOSTLY CONFINED TO THE LAKE SHORES. AS A RESULT...MOST LOCATIONS AWAY FROM THE AFOREMENTIONED AREA WILL SEE PARTLY IF NOT MOSTLY SUNNY SKIES FOR MUCH OF THE DAY. HIGHS IN THE LOW TO MID 20S LOOK FINE. TONIGHT...SHEARED TROUGH AXIS WILL PASS ACROSS THE STATE AND MID/UPPER LEVEL MOISTURE WILL THIN AS A RESULT. DO NOT BELIEVE THESE CLOUDS WILL HAVE MUCH OF AN IMPACT ON TEMPERATURES AND EXPECT ANOTHER EXCELLENT RADIATIONAL COOLING NIGHT IS IN STORE WITH SURFACE HIGH PRESSURE MAINTAINING ITS DOMINANCE ACROSS THE AREA. ONLY POSSIBLE PITFALL IS THAT LOW LEVEL WINDS INCREASE LATE AND SHALLOW INSTABILITY MAY BE ENOUGH FOR A COUPLE FLURRIES ALONG THE LAKE MICHIGAN SHORELINE. BUT THINK DRY AIR (850-700MB RH AROUND 10-20 PCT) AND LAND BREEZE INTERACTION WILL BE ENOUGH TO THWART ANY FLURRY ACTIVITY. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. MONDAY AND MONDAY NIGHT...SHORTWAVE RIDGING MOVES IN ON MONDAY WHILE THE BROAD SURFACE HIGH PRESSURE SHIFTS SOUTH OF THE GREAT LAKES. WEAK WARM ADVECTION WILL ENSUE...ENOUGH TO BUMP UP TEMPS INTO THE LOW 30S. OUTSIDE OF SOME MORNING LAKE CLOUDS AND RESULTING DIURNAL CU (WHICH SHOULD MIX OUT BY EARLY AFTERNOON) AS WEST FLOW STRENGTHENS...MOST AREAS WILL SEE MOSTLY SUNNY SKIES BY MID TO LATE AFTERNOON. MID/UPPER LEVEL CLOUDS WILL BE ON THE INCREASE TOWARDS EVENING AS MOISTURE SPREADS IN AHEAD OF THE NEXT CLIPPER SHORTWAVE. ISENTROPIC ASCENT INCREASES AS WELL...BUT LIMITED MOISTURE BELOW 700MB WILL PREVENT ANY PRECIP FROM REACHING THE GROUND. WITH STRENGTHENING SW FLOW AND INVASION OF WARMER AIR...LOWS WILL BE 15 TO 20 DEGREES WARMER THAN SUNDAY NIGHT. TUESDAY THROUGH THURSDAY...APPROACHING CLIPPER SHORTWAVE PASSES ACROSS LAKE SUPERIOR AND NORTHERN LAKE HURON ON TUESDAY. BEST QG FORCING WILL LIE AHEAD AND TO THE NORTH OF THE SHORTWAVE. GFS IS AN OUTLIER IN THIS REGARD...AND BRINGS A WEAK ASSOCIATED SURFACE LOW AND WIDE SWATH OF PRECIP ACROSS NORTHERN LOWER...WHILE OTHER LEADING MODELS KEEP PRECIP CHANCES NORTH OF THE STRAITS. REGARDLESS...THERMAL PROFILES SUGGEST PRECIP WILL FALL AS ALL SNOW...EVEN IN THE SOUTHERN GFS SOLUTION AND HAVE REMOVED RAIN MENTION. WILL KEEP LOW CHANCE POP ALL THE WAY TO M-55 HOWEVER...BUT WOULDN/T BE SURPRISED IF PRECIP CHANCES ARE REMOVED ACROSS THE SOUTHERN CWA. SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE RETURN TUESDAY NIGHT INTO WEDNESDAY. A CHANCE OF PRECIP THEN ARRIVES WEDNESDAY NIGHT INTO THURSDAY. HIGH TEMPERATURES IN THE UPPER 30S TO LOW 40S OVER THIS PERIOD. MPC && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 741 AM EDT SUN MAR 9 2008 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH STRETCHING FROM NEW ENGLAND INTO THE GREAT LAKES REGION. WEAK ENE FLOW AHEAD OF SFC RIDGE OVER ONTARIO LOOKS LIKE IT MAY STILL BE PRODUCING FLURRIES IN DOWNTOWN MQT BUT OTHERWISE DRY CONDITIONS PREVAIL OVER THE REST OF THE CWA. && .DISCUSSION... TODAY...SOME LIGHT LES IS STILL POSSIBLE OVER NCNTRL AREAS FAVORED BY A ENE FLOW AS 850 MB TEMPS ARE AROUND -15C. SOME INCREASE IN LOW LEVEL MOISTURE COMBINED WITH DIURNAL HEATING AND FAIRLY STEEP SFC-850 MB LAPSE RATES OF 7C/KM OR GREATER COULD LEAD TO SOME ISOLATED DIURNAL SNOW SHOWERS OVER THE INTERIOR WEST HALF THIS AFTERNOON AS A WEAK SFC TROF MOVES ACROSS THE AREA. IF THE WRF-ARW QPF VERIFIES...A FEW LOCATIONS UNDER THE HEAVIER SNOW SHOWERS COULD SEE CLOSE TO AN INCH OF SNOW ACCUMULATION USING A 25/1 SNOW/WATER RATIO. TONIGHT...EXPECT CLEARING SKIES AS THE SFC RIDGE FROM ONTARIO DESCENDS OVER THE AREA. WITH LIGHT WINDS AND PCPN WATER AROUND .1 INCH...LOOK FOR IDEAL RADIATIONAL COOLING CONDITIONS. I FOLLOWED THE COLDER GFS BIAS-CORRECTED MOS GUIDANCE WHICH HIGHLIGHTED MIN TEMPS REACHING AROUND -15F IN SOME INTERIOR LOCATIONS OF THE EAST HALF. THESE FCST TEMPS SEEM TOTALLY REASONABLE GIVEN READINGS OBSERVED UPSTREAM THIS MORNING OVER ONTARIO IN PROXIMITY TO THE RIDGE. LOWS COULD EVEN DROP CLOSE TO -10F FOR FAVORED COLD SPOTS IN THE WESTERN INTERIOR BEFORE BOUNDARY LYR WINDS INCREASE OVERNIGHT ON BACK SIDE OF RIDGE AND AHEAD OF NEXT APPROACHING CLIPPER SYSTEM. AFTER A DRY MONDAY WITH TEMPERATURES WARMING BACK TOWARD THE FREEZING MARK IN WSW RETURN FLOW...CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT. MODELS INDICATE TROUGH WILL NOT DIG ENOUGH TO THE SOUTHWEST TO BRING MUCH PCPN INTO UPR MI. BETTER CHANCES FOR PCPN WILL BE OVR LAKE SUPERIOR AND THE ERN FCST AREA CLOSER TO THE TRACK OF THE SHORTWAVE AND ASSOC SFC LOW. KEPT IN A SLIGHT CHC FOR NRN AND ERN TIER COUNTIES MON NIGHT WITH A SLIGHT CHC FOR ALL OF THE CWA ON TUE EXCEPT FOR LOW CHC POPS IN THE EAST. MODELS 1000-850MB THICKNESSES AND FCST SNDGS SUPPORT MORE SNOW AS PREDOMINANT PCPN TYPE MON NIGHT AND TUE. A VERY SHALLOW WARM LAYER NEAR SFC WITH DOWNSLOPING NW WINDS COULD SUPPORT A RAIN/SNOW MIX IN THE FAR SOUTH CENTRAL CWA. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... A STREAM OF MVFR CEIGS THE DEVELOPED OVER UPPER MICHIGAN PRIOR TO 09Z...BUT HAS SIGNIFICANTLY WEAKENED SINCE THEN. SO MOSTLY VFR CONDITIONS WILL CONTINUE...BUT HAVE TO WORRY ABOUT MVFR CIGS POSSIBLY COMING IN FROM THE LAKE WITH NE FLOW AND POSSIBLE UPSLOPE THROUGH THIS AFTERNOON. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... 30.4 INCH HIGH PRESSURE WILL MOVE OVERHEAD LATE THIS AFTERNOON...BEFORE SLOWLY SHIFTING SOUTH TO WESTERN KENTUCKY BY LATE TUESDAY NIGHT. 29.8 INCH LOW PRESSURE FROM MANITOBA MONDAY AFTERNOON...WILL MOVE TO JUST NORTH OF LAKE SUPERIOR TUESDAY MORNING BEFORE SLIDING ACROSS UPPER MICHIGAN TUESDAY AFTERNOON. THIS LOW WILL BRING ABOUT THE NEXT CHANCE OF WINDS AT OR ABOVE 25 KTS. HIGH PRESSURE OF 30.0 INCHES WILL THEN BRIEFLY TAKE OVER TUESDAY NIGHT INTO EARLY WEDNESDAY. A 29.4 INCH LOW WILL MOVE INTO MANITOBA WEDNESDAY AND THROUGH CENTRAL LAKE SUPERIOR ON THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...HEAVY FREEZING SPRAY WARNING THROUGH 8 AM EDT SUNDAY FOR LSZ267. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION...KF MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 705 AM EDT SUN MAR 9 2008 .AVIATION...VERY FEW CONCERNS OVER THE NEXT 24 HOURS. LAKE CLOUDS WILL PRODUCE MVFR CIGS AND FLURRIES AT TVC THIS MORNING. WEAKENING WIND FIELDS COMBINED WITH MIXING SHOULD HELP CIGS RISE AND SCATTER BY MIDDAY OR NOT TOO LONG THEREAFTER. OUTSIDE OF POSSIBLE DIURNAL CU AROUND MIDDAY AT APN...ALL TAF SITES SHOULD SEE VFR CONDITIONS PREVAIL. MPC && .PREV DISCUSSION... /ISSUED 422 AM EDT SUN MAR 9 2008/ DISCUSSION...03Z SURFACE/RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A PERSISTENT AMPLIFIED PATTERN (POSITIVE PNA) ACROSS NORTH AMERICA...WITH THE EASTERN TROUGH CONSISTING OF DUAL 500MB CLOSED LOWS...ONE OVER MINNESOTA...AND THE OTHER OVER UPSTATE NEW YORK. WHILE THE LATTER IS EXITING TO THE NE...SMALLER SCALE SHORTWAVES ROTATING AROUND THE WESTERN UPPER LOW IS SUPPORTING LIGHT SNOW OVER MN AND IA IN A REGION OF MODEST 850-500MB -DIVQ. AIR ACROSS NORTHERN LOWER MICHIGAN IS MUCH DRIER JUDGING BY THE 00Z SOUNDINGS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION THANKS TO LOW LEVEL RIDGING AND A POLAR CONTINENTAL AIRMASS. BECAUSE OF THIS DRY AIR...5-10KFT CLOUD DECK SPREADING EAST ACROSS WI/IL IS HAVING A DEVIL OF A TIME EXTENDING INTO NORTHERN MICHIGAN...RATHER PREFERRING TAKING A MORE SOUTHERN TRACK ACROSS SOUTHERN LOWER. ONLY A FEW LAKE EFFECT SNOW SHOWERS EXIST FROM MANISTEE TO THE LEELANAU PENINSULA AT THIS HOUR. FORECAST CONCERNS ARE MINIMAL FOR THIS TIME OF THE YEAR...AND CONSISTENT OF NUISANT LAKE EFFECT SNOW SHOWER POTENTIAL FIRST...THEN SKY AND TEMPS SECOND OVER THE NEXT 24 HOURS. TODAY...CLOSED LOW OVER MN WILL SHEAR OUT AS IT MIGRATES TOWARDS THE SOUTHERN GREAT LAKES. MID/UPPER LEVEL MOISTURE WILL ROTATE AROUND THE WEAK IOWA SHORTWAVE...PROGGED TO TRACK ACROSS NORTHERN IL/IN/OH...AND SPREAD MID/HIGH CLOUDS ACROSS NORTHERN MICHIGAN...THICKER AS YOU HEAD SOUTH. HOWEVER...VERY DRY AIR CENTERED AROUND 750MB WITH TRAJECTORIES ORIGINATING OUT OF NE ONTARIO AND QUEBEC WILL KEEP THE AREA PRECIP FREE. LAKE EFFECT WILL CONTINUE TO STRUGGLE TO REV UP ESPECIALLY WITH 850MB TEMPS MODERATING FROM -15C TO -13C AND LOW LEVEL WIND FLOW DIMINISHING TO LESS THAN 10KTS BY THIS AFTERNOON. THINK THAT ANY LIGHT SNOW SHOWER AND FLURRY ACTIVITY WILL BE CONFINED TO THE MORNING HOURS FROM THE MANISTEE TO GRAND TRAVERSE BAY CORRIDOR AND BE MOSTLY CONFINED TO THE LAKE SHORES. AS A RESULT...MOST LOCATIONS AWAY FROM THE AFOREMENTIONED AREA WILL SEE PARTLY IF NOT MOSTLY SUNNY SKIES FOR MUCH OF THE DAY. HIGHS IN THE LOW TO MID 20S LOOK FINE. TONIGHT...SHEARED TROUGH AXIS WILL PASS ACROSS THE STATE AND MID/UPPER LEVEL MOISTURE WILL THIN AS A RESULT. DO NOT BELIEVE THESE CLOUDS WILL HAVE MUCH OF AN IMPACT ON TEMPERATURES AND EXPECT ANOTHER EXCELLENT RADIATIONAL COOLING NIGHT IS IN STORE WITH SURFACE HIGH PRESSURE MAINTAINING ITS DOMINANCE ACROSS THE AREA. ONLY POSSIBLE PITFALL IS THAT LOW LEVEL WINDS INCREASE LATE AND SHALLOW INSTABILITY MAY BE ENOUGH FOR A COUPLE FLURRIES ALONG THE LAKE MICHIGAN SHORELINE. BUT THINK DRY AIR (850-700MB RH AROUND 10-20 PCT) AND LAND BREEZE INTERACTION WILL BE ENOUGH TO THWART ANY FLURRY ACTIVITY. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. MONDAY AND MONDAY NIGHT...SHORTWAVE RIDGING MOVES IN ON MONDAY WHILE THE BROAD SURFACE HIGH PRESSURE SHIFTS SOUTH OF THE GREAT LAKES. WEAK WARM ADVECTION WILL ENSUE...ENOUGH TO BUMP UP TEMPS INTO THE LOW 30S. OUTSIDE OF SOME MORNING LAKE CLOUDS AND RESULTING DIURNAL CU (WHICH SHOULD MIX OUT BY EARLY AFTERNOON) AS WEST FLOW STRENGTHENS...MOST AREAS WILL SEE MOSTLY SUNNY SKIES BY MID TO LATE AFTERNOON. MID/UPPER LEVEL CLOUDS WILL BE ON THE INCREASE TOWARDS EVENING AS MOISTURE SPREADS IN AHEAD OF THE NEXT CLIPPER SHORTWAVE. ISENTROPIC ASCENT INCREASES AS WELL...BUT LIMITED MOISTURE BELOW 700MB WILL PREVENT ANY PRECIP FROM REACHING THE GROUND. WITH STRENGTHENING SW FLOW AND INVASION OF WARMER AIR...LOWS WILL BE 15 TO 20 DEGREES WARMER THAN SUNDAY NIGHT. TUESDAY THROUGH THURSDAY...APPROACHING CLIPPER SHORTWAVE PASSES ACROSS LAKE SUPERIOR AND NORTHERN LAKE HURON ON TUESDAY. BEST QG FORCING WILL LIE AHEAD AND TO THE NORTH OF THE SHORTWAVE. GFS IS AN OUTLIER IN THIS REGARD...AND BRINGS A WEAK ASSOCIATED SURFACE LOW AND WIDE SWATH OF PRECIP ACROSS NORTHERN LOWER...WHILE OTHER LEADING MODELS KEEP PRECIP CHANCES NORTH OF THE STRAITS. REGARDLESS...THERMAL PROFILES SUGGEST PRECIP WILL FALL AS ALL SNOW...EVEN IN THE SOUTHERN GFS SOLUTION AND HAVE REMOVED RAIN MENTION. WILL KEEP LOW CHANCE POP ALL THE WAY TO M-55 HOWEVER...BUT WOULDNT BE SURPRISED IF PRECIP CHANCES ARE REMOVED ACROSS THE SOUTHERN CWA. SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE RETURN TUESDAY NIGHT INTO WEDNESDAY. A CHANCE OF PRECIP THEN ARRIVES WEDNESDAY NIGHT INTO THURSDAY. HIGH TEMPERATURES IN THE UPPER 30S TO LOW 40S OVER THIS PERIOD. MPC AVIATION.../ISSUED 1112 PM EST SAT MAR 8 2008/ A QUIET 24 HOURS COMING UP WITH LIGHT WINDS AND CLEAR SKIES. THE ONLY CLOUDS THAT WILL BE AROUND WILL BE SCT HIGH CLOUDS ABOVE 20000 FT OR SOME SCT LAKE CLOUDS AROUND 3500 FT. NO PRECIPITATION IS EXPECTED AT ANY OF THE TAF SITES DURING THE NEXT 24 HOURS. LUTZ && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 422 AM EDT SUN MAR 9 2008 .DISCUSSION...03Z SURFACE/RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A PERSISTENT AMPLIFIED PATTERN (POSITIVE PNA) ACROSS NORTH AMERICA...WITH THE EASTERN TROUGH CONSISTING OF DUAL 500MB CLOSED LOWS...ONE OVER MINNESOTA...AND THE OTHER OVER UPSTATE NEW YORK. WHILE THE LATTER IS EXITING TO THE NE...SMALLER SCALE SHORTWAVES ROTATING AROUND THE WESTERN UPPER LOW IS SUPPORTING LIGHT SNOW OVER MN AND IA IN A REGION OF MODEST 850-500MB -DIVQ. AIR ACROSS NORTHERN LOWER MICHIGAN IS MUCH DRIER JUDGING BY THE 00Z SOUNDINGS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION THANKS TO LOW LEVEL RIDGING AND A POLAR CONTINENTAL AIRMASS. BECAUSE OF THIS DRY AIR...5-10KFT CLOUD DECK SPREADING EAST ACROSS WI/IL IS HAVING A DEVIL OF A TIME EXTENDING INTO NORTHERN MICHIGAN...RATHER PREFERRING TAKING A MORE SOUTHERN TRACK ACROSS SOUTHERN LOWER. ONLY A FEW LAKE EFFECT SNOW SHOWERS EXIST FROM MANISTEE TO THE LEELANAU PENINSULA AT THIS HOUR. FORECAST CONCERNS ARE MINIMAL FOR THIS TIME OF THE YEAR...AND CONSISTENT OF NUISANT LAKE EFFECT SNOW SHOWER POTENTIAL FIRST...THEN SKY AND TEMPS SECOND OVER THE NEXT 24 HOURS. TODAY...CLOSED LOW OVER MN WILL SHEAR OUT AS IT MIGRATES TOWARDS THE SOUTHERN GREAT LAKES. MID/UPPER LEVEL MOISTURE WILL ROTATE AROUND THE WEAK IOWA SHORTWAVE...PROGGED TO TRACK ACROSS NORTHERN IL/IN/OH...AND SPREAD MID/HIGH CLOUDS ACROSS NORTHERN MICHIGAN...THICKER AS YOU HEAD SOUTH. HOWEVER...VERY DRY AIR CENTERED AROUND 750MB WITH TRAJECTORIES ORIGINATING OUT OF NE ONTARIO AND QUEBEC WILL KEEP THE AREA PRECIP FREE. LAKE EFFECT WILL CONTINUE TO STRUGGLE TO REV UP ESPECIALLY WITH 850MB TEMPS MODERATING FROM -15C TO -13C AND LOW LEVEL WIND FLOW DIMINISHING TO LESS THAN 10KTS BY THIS AFTERNOON. THINK THAT ANY LIGHT SNOW SHOWER AND FLURRY ACTIVITY WILL BE CONFINED TO THE MORNING HOURS FROM THE MANISTEE TO GRAND TRAVERSE BAY CORRIDOR AND BE MOSTLY CONFINED TO THE LAKE SHORES. AS A RESULT...MOST LOCATIONS AWAY FROM THE AFOREMENTIONED AREA WILL SEE PARTLY IF NOT MOSTLY SUNNY SKIES FOR MUCH OF THE DAY. HIGHS IN THE LOW TO MID 20S LOOK FINE. TONIGHT...SHEARED TROUGH AXIS WILL PASS ACROSS THE STATE AND MID/UPPER LEVEL MOISTURE WILL THIN AS A RESULT. DO NOT BELIEVE THESE CLOUDS WILL HAVE MUCH OF AN IMPACT ON TEMPERATURES AND EXPECT ANOTHER EXCELLENT RADIATIONAL COOLING NIGHT IS IN STORE WITH SURFACE HIGH PRESSURE MAINTAINING ITS DOMINANCE ACROSS THE AREA. ONLY POSSIBLE PITFALL IS THAT LOW LEVEL WINDS INCREASE LATE AND SHALLOW INSTABILITY MAY BE ENOUGH FOR A COUPLE FLURRIES ALONG THE LAKE MICHIGAN SHORELINE. BUT THINK DRY AIR (850-700MB RH AROUND 10-20 PCT) AND LAND BREEZE INTERACTION WILL BE ENOUGH TO THWART ANY FLURRY ACTIVITY. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. MONDAY AND MONDAY NIGHT...SHORTWAVE RIDGING MOVES IN ON MONDAY WHILE THE BROAD SURFACE HIGH PRESSURE SHIFTS SOUTH OF THE GREAT LAKES. WEAK WARM ADVECTION WILL ENSUE...ENOUGH TO BUMP UP TEMPS INTO THE LOW 30S. OUTSIDE OF SOME MORNING LAKE CLOUDS AND RESULTING DIURNAL CU (WHICH SHOULD MIX OUT BY EARLY AFTERNOON) AS WEST FLOW STRENGTHENS...MOST AREAS WILL SEE MOSTLY SUNNY SKIES BY MID TO LATE AFTERNOON. MID/UPPER LEVEL CLOUDS WILL BE ON THE INCREASE TOWARDS EVENING AS MOISTURE SPREADS IN AHEAD OF THE NEXT CLIPPER SHORTWAVE. ISENTROPIC ASCENT INCREASES AS WELL...BUT LIMITED MOISTURE BELOW 700MB WILL PREVENT ANY PRECIP FROM REACHING THE GROUND. WITH STRENGTHENING SW FLOW AND INVASION OF WARMER AIR...LOWS WILL BE 15 TO 20 DEGREES WARMER THAN SUNDAY NIGHT. TUESDAY THROUGH THURSDAY...APPROACHING CLIPPER SHORTWAVE PASSES ACROSS LAKE SUPERIOR AND NORTHERN LAKE HURON ON TUESDAY. BEST QG FORCING WILL LIE AHEAD AND TO THE NORTH OF THE SHORTWAVE. GFS IS AN OUTLIER IN THIS REGARD...AND BRINGS A WEAK ASSOCIATED SURFACE LOW AND WIDE SWATH OF PRECIP ACROSS NORTHERN LOWER...WHILE OTHER LEADING MODELS KEEP PRECIP CHANCES NORTH OF THE STRAITS. REGARDLESS...THERMAL PROFILES SUGGEST PRECIP WILL FALL AS ALL SNOW...EVEN IN THE SOUTHERN GFS SOLUTION AND HAVE REMOVED RAIN MENTION. WILL KEEP LOW CHANCE POP ALL THE WAY TO M-55 HOWEVER...BUT WOULDNT BE SURPRISED IF PRECIP CHANCES ARE REMOVED ACROSS THE SOUTHERN CWA. SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE RETURN TUESDAY NIGHT INTO WEDNESDAY. A CHANCE OF PRECIP THEN ARRIVES WEDNESDAY NIGHT INTO THURSDAY. HIGH TEMPERATURES IN THE UPPER 30S TO LOW 40S OVER THIS PERIOD. MPC && AVIATION.../ISSUED 1112 PM EST SAT MAR 8 2008/ A QUIET 24 HOURS COMING UP WITH LIGHT WINDS AND CLEAR SKIES. THE ONLY CLOUDS THAT WILL BE AROUND WILL BE SCT HIGH CLOUDS ABOVE 20000 FT OR SOME SCT LAKE CLOUDS AROUND 3500 FT. NO PRECIPITATION IS EXPECTED AT ANY OF THE TAF SITES DURING THE NEXT 24 HOURS. LUTZ && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1203 AM EST SUN MAR 9 2008 UPDATED FOR 06Z AVIATION .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH OVER THE ERN CONUS WITH A MID LEVEL LOW OVER WV/OH ERN MANITOBA INTO NW MN. THIS LEFT UPPER MI BETWEEN THE TWO SYSTEMS WITH MID LEVEL AND SFC RIDGING. VIS SATELLITE AND RADAR SHOWED THAT THE COMBINATION OF VERY DRY AIR UPSTREAM AND DAYTIME HEATING/MIXING HAD HELPED REDUCE REMAINING ENE FLOW LAKE EFFECT SNOW SHOWERS TO ONLY A FEW FLURRIES VCNTY MARQUETTE. LIGHT SNOW ACROSS NW MN ASSOCIATED WITH THE MID LEVEL LOW AND SFC TROF SLIDING MAINLY TO THE SSE. && .SHORT TERM...(TONIGHT AND SUNDAY) EXPECT SOME INCREASE IN MID/UPPER LEVEL MOISTURE AS THE MID LEVEL LOW MOVES THROUGH MN. HOWEVER...SFC-700 MB MOISTURE WILL REMAIN SCARCE. RADIATIONAL COOLING WILL NOT BE QUITE AS FAVORABLE AS LAST NIGHT BUT STILL SHOULD ALLOW TEMPS TO DROP OFF TO -5 TO -10F INLAND WITH READINGS 0 TO 10F NEAR THE LAKE SUPERIOR N CNTRL. 850 MB TEMPS NEAR -16C...INCREASING ENE 950 WIND INTO THE 10 TO 20 KT RANGE ALONG WITH LAND BREEZE DEVELOPMENT SHOULD ALLOW LES TO REGENERATE WITH SOME SCT -SHSN INTO N CNTRL UPPER MI. HOWEVER...GIVEN THE VERY DRY LOW LEVEL AIR REMAINING AND GENERAL ACYC FLOW ANY ACCUMULATIONS SHOULD BE MINIMAL...UNDER AN INCH. LES MAY AGAIN BE POSSIBLE...MAINLY IN THE MORNING N CNTRL IN AREAS FAVORED BY ENE FLOW. SOME INCREASE IN LOW LEVEL MOISTURE ALONG WITH DIURNAL HEATING COULD LEAD TO A FEW FLURRIES IN ADDITION TO SCT-BKN SC INLAND. WITH NO ACCUMULATION EXPECTED...FCST DOES NOT INCLUDE POPS FOR NOW. .LONG TERM (SUNDAY NIGHT THROUGH NEXT SATURDAY)... RELATIVELY TRANQUIL FOR MUCH OF THE PERIOD. ALONG WITH A PERSISTENT WARM UP...STILL APPEARS THAT TWO MAIN NORTHERN BRANCH ORIGIN TROUGHS WILL AFFECT THE AREA WITH CHANCES FOR MAINLY LIGHT PCPN. AFTER A DRY MONDAY WITH TEMPERATURES WARMING BACK TOWARD NORMAL...CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT. TROUGH APPEARS TO NOT DIG ENOUGH TO THE SOUTHWEST TO BRING MUCH PCPN INTO UPR MI. BETTER CHANCES FOR PCPN RESIDE OVR LK SUPERIOR CLOSER TO THE TRACK OF THE SHORTWAVE. BASED ON TRENDS FM 1000-850MB THICKNESSES FM GFS/ECMWF SCALED BACK THE CHANCE OF ANY RAIN ON TUE. SOUNDINGS SHOW A VERY SHALLOW WARM LAYER NEAR SFC...ESPECIALLY WHERE NW WINDS DOWNSLOPE IN SOUTH CENTRAL CWA. GRADUAL HEIGHT RISES FIRST COUPLE DAYS OF THE WEEK ARE REPLACED BY MUCH MORE SIGNIFICANT HEIGHT RISES/WARM AIR ADVECTION ON WED. GFS NOW JOINS EARLIER RUNS OF ECMWF/UKMET/CANADIAN IN TRENDING MUCH SHARPER WITH TROUGH DEVELOPING OVR NORTHERN PLAINS BY 00Z THU. 1000-500MB THICKNESSES ABOVE 540DAM...H9 TEMPS NEAR ZERO...AND INCREASING SOUTH WINDS AHEAD OF LOW PRESSURE TROUGH SUPPORT TEMPS INTO THE MID-UPR 30S. TRICK TO FORECAST THEN ARRIVES WED NIGHT AS PCPN DRIVEN BY RIGHT ENTRANCE OF JET OVR ONTARIO AND ISENTROPIC LIFT WILL BE POISED TO CROSS THE REGION. GFS WARMER THAN ECMWF BUT ECMWF IS COOLER THAN 00Z RUN YDY. CONFIDENCE INCREASING THAT PCPN WILL OCCUR (LATEST ECMWF SHOWS QPF UP TO A HALF INCH 00Z THU THROUGH 00Z FRI)...BUT STILL UNCERTAINTY FOR EXPECTED PTYPE. EXPECT A MIX OF RAIN/SNOW...PERHAPS FOR THE ENTIRE TIME OR MAYBE AFTER A PERIOD OF SNOW INITIALLY ON WED NIGHT. IF TEMPS WARM AS EXPECTED ON WED...THEN NOT TOO CONCERNED WITH POTENTIAL FOR FREEZING RAIN AS IT WOULD NOT BE A CASE OF AN ELEVATED WARM LAYER JUST A RAIN OR SNOW QUESTION BASED ON THE TEMPERATURE IN THE BLYR. TIMING AND EXACT PTYPE WILL LIKELY CHANGE BEFORE WED NIGHT AS MODELS HAVE NOT HONED IN ON EXACT IDEA QUITE YET. PCPN TAPERS OFF THU NIGHT ONCE TEMPS BECOME SUFFICIENTLY COLDER FOR JUST SNOW. TROUGH WITH MARGINALLY COLD AIR FOR DIURNAL AND/OR LK EFFECT SNOW SHOWERS REMAINS OVER THE GREAT LAKES FRIDAY INTO SATURDAY. SO...AFTER A BRIEF WARMING TREND THE MIDDLE OF THIS WEEK...TEMPS WILL RETURN TO NORMAL OR SLIGHTLY BLO NORMAL VALUES BY NEXT WEEKEND. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... LAKE EFFECT SNOW WILL CONTINUE A WHILE LONGER AT KSAW OVERNIGHT WITH NE FLOW OFF THE LAKE. WITH DRY AIR ON SUN...THINK VFR CONDITIONS WILL CONTINUE...BUT HAVE TO WORRY ABOUT MVFR CIGS POSSIBLY COMING IN FROM THE LAKE WITH NE FLOW AND POSSIBLE UPSLOPE. WILL GO WITH THE DRY AIR WINNING OUT AND KEEPING IT VFR FOR NOW. MVFR CIGS WILL MOVE BACK INTO KCMX WITH EAST WIND LATE TONIGHT...THEN AS THE WIND BECOMES LIGHT AND VAR LATE SUN...SHOULD GO BACK TO VFR. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... HEAVY FREEZING SPRAY WILL CONTINUE TONIGHT OVER EASTERN LAKE SUPERIOR AS NORTHEAST WINDS INCREASE INTO THE 15 TO 25 KNOT RANGE IN A TIGHTENING GRADIENT BTWN HIGH PRESSURE OVER NORTHERN ONTARIO AND A TROUGH INTO LOWER MI. THE HIGH SHOULD SHIFT TO OUR SOUTH ON MONDAY...MAKING WAY FOR A 29.8 INCH LOW OVER CENTRAL MANITOBA MONDAY NIGHT TO MOVE INTO NORTHERN ONTARIO TUESDAY. THE LOW WILL BRING INCREASED WRLY WINDS...UP TO 30 KNOTS. HIGH PRESSURE OF 30.0 INCHES WILL BRIEFLY TAKE OVER TUESDAY NIGHT AND WEDNESDAY...AS A 29.5 INCH LOW DEVELOPS OVER MANITOBA. && UPPER MICHIGAN...NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING THROUGH 8 AM EDT SUNDAY FOR LSZ267. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...JLB LONG TERM...JLA AVIATION...GJM MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 113 PM EDT SUN MAR 9 2008 .SYNOPSIS... THE LOW PRESSURE SYSTEM THAT BROUGHT THE WINTRY PRECIPITATION TO THE REGION WILL MOVE AWAY TO THE NORTHEAST TODAY. GUSTY SOUTHWEST TO WEST WINDS WILL BE QUITE STRONG THROUGH MIDDAY...ESPECIALLY IN THE CENTRAL ADIRONDACKS AND CENTRAL AND SOUTHERN VERMONT. LINGERING SNOW SHOWERS IN THE MOUNTAINS WILL TAPER OFF TONIGHT. TEMPERATURES WILL BE BELOW NORMAL THROUGH MIDWEEK...THEN A WARMING TREND WILL MOVE TEMPERATURES ABOVE NORMAL AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 929 AM EDT SUNDAY...THE NORTH COUNTRY REMAINS IN DEEP-LAYER CYCLONIC FLOW ON UPSTREAM SIDE OF DEPARTING LOW OVER NRN ME AT 1315Z. LATEST RUC ANALYSIS INDICATES BAND OF 45-55KT 850MB WINDS ACROSS OUR SRN ZONES...AND THIS SHOULD HELP CONTRIBUTE TO SOME WLY SFC WIND GUSTS OF 35-40 MPH IN THE ADVISORY AREA THROUGH LATE THIS MORNING. OVERALL GRADIENT WEAKENS THIS AFTERNOON...SO CURRENT PLAN IS TO DROP THE WIND ADVISORY ON TIME AT 15Z. BY 21Z...850MB FLOW BECOMES NWLY AND DECREASES TO 30-35 KTS. OTHERWISE...EXPECT A FEW SUNNY BREAKS TO DEVELOP...ESPECIALLY THIS AFTN. DOWNSLOPE FLOW COMPONENT SHOULD ALSO FAVOR DIMINISHING CLOUDS EAST OF THE ADIRONDACKS IN THE CHAMPLAIN VALLEY AND EAST OF THE GREEN MTNS TOWARD/WITHIN THE CONNECTICUT RIVER VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... AS OF 0412 AM EDT SUNDAY...RIDGE OF HIGH PRESSURE POKING NORTHEAST OUT OF OHIO VALLEY INTO THE NORTHEAST WILL BRING FAIR WEATHER FOR THE FIRST PART OF THE WEEK. HOWEVER LOW HEIGHTS IN THE EASTERN US WILL KEEP TEMPS BELOW NORMAL. LOW RH AIR OVER THE REGION...SO SOME SUN EXPECTED. HOWEVER WITH TROFINESS OVER EASTERN US AND VICINITY OF JET...DON`T THINK IT WILL BE QUITE AS CLOUD FREE AS MOS WOULD LIKE. WENT A DEGREE OR TWO WARMER THAN GUIDANCE MONDAY AND TUESDAY COUNTING ON SOME MORE SUNSHINE TO WARM US UP. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 0412 AM EDT SUNDAY...CLIPPER TYPE SYSTEM TO DIVE DOWN IN NORTHWEST FLOW LATE TUESDAY INTO WEDNESDAY. TEMPS COLD ENOUGH FOR SNOW...BUT WITH LESS MOISTURE TO WORK WITH ONLY CHC POPS. SHORTWAVE RIDGING FOLLOWS...THEN A WARM FRONT THURSDAY FOLLOWED BY COLD FRONT ON FRIDAY. CHC POPS...WITH SOME RAIN MIXED IN ON THURSDAY WITH WARMER TEMPS. && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... THROUGH 18Z MONDAY...MAINLY VFR/MVFR COND EXPECTED AT ALL FORECAST SITES THRU 00Z MON. KSLK MAY SEE SOME IFR -SW FROM 18Z-21Z THAT MAY REDUCE VSBY TO LESS THAN 3SM AT TIMES. OTHERWISE...CEILINGS THRU 00Z MON WILL VARY FROM VFR TO MVFR. AFT 00Z MON...MAINLY VFR COND FOR ALL SITES AS HIGH PRESSURE BUILDS IN FROM THE WEST...AND EVENTUALLY NEAR SCT BY 18Z MONDAY. SOME MVFR CEILINGS AT KSLK FROM 00Z-04Z MON. WINDS CURRENTLY WNW 10-20KTS WITH SOME HIR GUSTS...WILL BECM LIGHTER THRU FORECAST PERIOD TO 10KTS OR LESS BY 00Z MON. HIR TRRN OBSCD AT TIMES. 18Z MONDAY THROUGH THURSDAY...VFR CONDITIONS EXPECTED OVER THE REGION MONDAY AND TUESDAY...AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES. A WEAK AREA OF LOW PRESSURE WILL MOVE SOUTHEAST FROM THE GREAT LAKES TUESDAY NIGHT AND WEDNESDAY...BRINGING A CHANCE FOR SOME LIGHT SNOW SHOWERS ALONG WITH MVFR/IFR CONDITIONS. ANOTHER RIDGE OF HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES WEDNESDAY NIGHT...BRINGING VFR CONDITIONS TO THE REGION WEDNESDAY NIGHT AND THURSDAY. && .HYDROLOGY... AS OF 0412 AM EDT SUNDAY...WILL EXTEND FLOOD WATCH TO UNTIL THIS AFTERNOON. SMALLER TRIBS CRESTING ONLY NOW...AND OTTER CREEK AT CENTER RUTLAND AND OTHER MAINSTEM RIVERS CONTINUE TO RISE. SOUTHERN VERMONT RECEIVED 1.5 TO 2 INCHES ALL LIQUID OVER THE PAST 24 HOURS...AND WATERWAYS RUNNING HIGH. IN ADDITION TO OPEN WATER FLOOD POTENTIAL...THESE RISES HAVE RIVER ICE BREAKING UP AND MOVING ON CENTRAL AND SOUTHERN VT RIVERS. KNOWN ICE JAM ON THE MAD RIVER AT MORETOWN VT...AND VT HIGHWAY DEPT REPORTS A JAM MOVING DOWN THE FIRST BRANCH OF THE WHITE RIVER ALONG ROUTE 110 IN THE CHELSEA/TUNBRIDGE/SOUTH ROYALTON AREA. COLD AIR SPREADING OVER REGION IS A HELP BY FREEZING UP THE RUNOFF...AND WILL ALLOW RIVERS TO BEGIN TO RECEDE. IN EXTENDED...FORECAST LOOKS GOOD FOR END OF WEEK FOR SOME WELL REGULATED SNOWMELT RUNOFF...40S IN THE DAY AND 20S AT NIGHT WILL HELP MELT SOME SNOW AND GET THE WATER INTO THE RIVERS IN AN ORDERLY FASHION. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLOOD WATCH UNTIL 5 PM EDT THIS AFTERNOON FOR VTZ009>012-018- 019. NY...NONE. && $$ SYNOPSIS...HANSON NEAR TERM...BANACOS SHORT TERM...HANSON LONG TERM...HANSON AVIATION...WGH/JN HYDROLOGY...BANACOS ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 950 AM EDT MON MAR 10 2008 .SYNOPSIS... HIGH PRESSURE OVER THE MID ATLANTIC AND SOUTHEAST STATES TODAY WILL DRIFT OFF THE COAST THIS EVENING. A WEAK DRY COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE WILL EXTEND INTO THE AREA FROM THE GULF STATES TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 950 AM MONDAY... THIS AFTERNOON...WV IMAGERY AND RUC ANALYSIS SUGGEST SOME STRENGTHENING OF PJ THAT EXTENDS SW TO NE FROM THE TN VALLEY TO OFF THE MID ATLANTIC COAST...AIDING IN SOME ENHANCEMENT OF CIRRUS ACROSS THE REGION. THIS IN RESPONSE TO THE NORTHERN STREAM IMPULSE...DIVING SE THROUGH THE OHIO VALLEY...WHICH IS PROGGED TO MOVE THROUGH THE AREA OVERNIGHT. OTHERWISE...MOSTLY SKIES ARE EXPECTED THROUGH THE MAJORITY OF THE AFTERNOON...WITH AN INCREASE IN MID AND HIGH CLOUDS LATE IN THE AFTERNOON/EARLY EVENING IN ADVANCE OF THE SHORTWAVE TROUGH. WEAK LOW-LEVEL WAA WILL ENSUE THIS AFTERNOON AS LOW-LEVEL WIND PROFILE VEERS AROUND TO SW. THICKNESSES THIS MORNING VERIFIED AT 1320M THIS MORNING AT KGSO...VERY CLOSE TO THE NORMAL THICKNESS (1324M)FOR THIS DATE...ARE EXPECTED TO INCREASE TO AROUND 1335M. THIS WOULD YIELD A 5 TO 6 DEGREE INCREASE FROM SUNDAY`S HIGH TEMPERATURES...SUPPORTING HIGHS IN THE UPPER 50S TO LOWER 60S. TONIGHT... ALTHOUGH THERE WILL BE UPPER LEVEL LIFT IN THE FORM OF DPVA...AND SFC LIFT ASSOC/W A WEAK COLD FRONTAL PASSAGE (PRIMARILY BETWEEN 00-09Z TONIGHT)...THE LIFT WILL BE RATHER WEAK BECAUSE THE UPPER LEVEL WAVE WILL BE DE-AMPLIFYING AND THE SFC BOUNDARY ASSOC/W THE WEAK LOW MOVING EAST THROUGH THE DELMARVA WILL BRING ONLY WEAK/SHALLOW LOW LEVEL CONVERGENCE. ADDITIONALLY...WITH WESTERLY FLOW GENERALLY THROUGHOUT MOST OF THE COLUMN...THE ATMOSPHERE WILL BE RATHER DRY TONIGHT...WITH FCST PWAT VALUES OF 0.50" OR LESS. BOTH THE GFS/NAM KEEP ANY LIGHT MEASURABLE PRECIP ASSOC/W THIS SYSTEM WELL NORTH OF CENTRAL NC...AND ALONG THE FAVORABLE UPSLOPE AREAS ALONG/WEST OF THE RIDGELINE IN WV/VA. THEREFORE...ALTHOUGH WE WILL LIKELY SEE CLOUDY SKIES AT TIMES...WILL KEEP THE FORECAST DRY DUE TO THE ANEMIC AMOUNT OF MOISTURE/LIFT PROGGED. LOW TEMPS MAY BE A BIT TRICKY DEPENDING ON THE TIMING/EXTENT OF ANY CLOUD COVER...BUT A RANGE OF 35-41F SUGGESTED BY THE LATEST MOS GUIDANCE APPEARS REASONABLE. -VINCENT && .SHORT TERM /TUESDAY THROUGH THURSDAY/... AS OF 245 AM MONDAY... TUESDAY AND TUESDAY NIGHT: WNW/NW FLOW ALOFT WILL GENERALLY BE PRESENT IN THE UPPER LEVELS BEHIND THE DEPARTING UPPER LEVEL WAVE DURING THE DAY TUESDAY. THERE MAY BE SOME VERY WEAK SFC AND UPPER LEVEL TROUGHING PERSISTING OVER THE CAROLINAS DURING THE DAY (LOOKS LIKE A PIECE OF ENERGY FROM THE UPPER LEVEL WAVE PASSING THROUGH THE AREA TONIGHT BREAKS OFF AND LINGERS)...AND THE NAM IS A BIT MORE AGGRESSIVE IN SHOWING THIS THAN THE GFS. THE GFS PROGS PWAT VALUES AROUND 0.20" ON TUESDAY...WHILE THE NAME IS OVER TWICE AS MOIST WITH PWAT VALUES IN THE 0.45" RANGE. THE ONLY REAL DIFFERENCE THIS COULD MAKE IN THE FORECAST IS WITH TEMPS AND WHETHER OR NOT DIURNAL CU WILL DEVELOP DURING THE AFTERNOON HOURS TUE. W/REGARDS TO TEMPS...THE NAM FCST SOUNDINGS ARE SHOWING DEEP MIXING ON TUE...UP TO 750MB...WHILE THE GFS FCST SOUNDINGS ARE QUITE A BIT SHALLOWER...MIXING UP TO ONLY 850-900MB. THICKNESSES ARE PROGGED TO RANGE FROM 1315-1340 METERS 12Z TUE... INCREASING TO 1330-1350 METERS DURING THE AFTERNOON. THE GFS THICKNESSES ARE COLDER THAN THE NAM BY 5-15 METERS. LOCAL TEMP RESEARCH SUGGEST A RANGE FROM THE UPPER 50S TO LOWER 60S ON TUE BASED ON THESE THICKNESSES. THE 850MB TEMPS OFF THE GFS/NAM VARY BY ABOUT 4C TUE AFTERNOON...WITH THE GFS BEING COLDER THAN THE NAM...AND USING THE DRY-ADIABATIC METHOD...THIS RESULTS IN A 5-8F DIFFERENCE IN HIGH TEMPS (UPPER 50S VERSUS LOWER/MID 60S). MOS GUIDANCE IS INDICATING HIGH TEMPS IN THE LOWER/MID 60S ON TUE. BEARING ALL OF THIS IN MIND...WILL TRY TO BLEND THE RESULTS FROM THESE DIFFERENT METHODS AND MOS GUIDANCE...AND FORECAST A RANGE OF 61-64F ACROSS THE AREA. OVERNIGHT...WITH CLEAR SKIES AND A RELATIVELY DRY AIRMASS IN PLACE...RADIATIONAL COOLING SHOULD BE CLOSE TO OPTIMAL...ALTHOUGH THE FCST MSLP GRADIENT SUGGESTS THERE MAY BE VERY LIGHT WINDS IN SOME LOCATIONS. LOW TEMPS IN THE MID 30S TO LOWER 40S LOOK REASONABLE...AND THIS IS WHAT MOS GUIDANCE IS SUGGESTING. WEDNESDAY AND WEDNESDAY NIGHT: A WEAK SOUTHERN STREAM TROUGH IS PROGGED TO TRANSLATE EAST ALONG THE GULF COAST ON WEDNESDAY...WHILE AN UPPER LEVEL TROUGH OVER NEW ENGLAND IS PROGGED TO LIFT ENE TOWARD NOVA SCOTIA. NORTH CAROLINA WILL REMAIN IN-BETWEEN THESE UPPER LEVEL SYSTEMS...AND BENIGN WEATHER IS EXPECTED TO CONTINUE DURING THE DAY WED...WITH MOSTLY SUNNY SKIES. ADDITIONALLY...WEAK SHORTWAVE RIDGING ALOFT IS PROGGED TO APPROACH THE STATE FROM THE WEST BY WED EVENING. THICKNESSES OFF THE GFS/NAM ON WED ARE VERY SIMILAR TO TUE...AND FCST SOUNDINGS OFF THE GFS/NAM ARE MUCH MORE IN-LINE WITH EACH OTHER THAN THEY ARE FOR TUE...BOTH SHOWING MIXING UP TO 850MB WITH 2-3C TEMPS AT THAT LEVEL. BASED ON THE THICKNESSES AND H85 TEMPS...WILL FORECAST MAX TEMPS A FEW DEGREES WARMER THAN TUE...RANGING FROM 63-67F...SLIGHTLY LOWER THAN MOS GUIDANCE IN MOST LOCATIONS. GOOD RADIATIONAL COOLING NIGHT APPEARS ON TAP WED NIGHT...AND WILL FORECAST LOW TEMPS RANGING FROM THE MID 30S TO LOWER 40S (COOLEST TEMPS IN RURAL AREAS). THURSDAY: WEAK SHORTWAVE RIDGING ALOFT IS PROGGED BY THE 00Z GFS/12Z ECMWF (NEWEST ECMWF NOT IN YET) TO CROSS OVER THE STATE ON THU. THE ECMWF SHOWS A NARROW SFC RIDGE AXIS (WEAK/DRY CAD SIGNATURE) IN THE LEE OF THE SOUTHERN APPALACHIANS THU MORNING...ASSOC/W 1025MB HIGH PRESSURE IN QUEBEC. THE GFS IS WEAKER WITH THE SFC HIGH IN CANADA...AND SHOWS NO HINT OF A SFC RIDGE AXIS IN THE LEE OF THE MOUNTAINS THU MORNING. THIS DIFFERENCE COULD HAVE AN IMPACT ON HIGH TEMPS THU...ALTHOUGH EVEN IF THE 12Z 03/09 ECMWF IS ON TO SOMETHING...NO DIABATIC ENHANCEMENT OF THE POTENTIAL WEDGE WOULD OCCUR...AND A VERY WEAK/DRY CAD SIGNAL WOULD NOT MAKE TOO MUCH OF A DIFFERENCE IN MAX TEMPS OVER CENTRAL NC ANYWAYS. BASED ON THE OVERALL SYNOPTIC PATTERN...MOSTLY SUNNY SKIES ARE EXPECTED ON THU (EXCEPT PERHAPS A FEW MID/UPPER LEVEL CLOUDS MOVING INTO THE AREA FROM UPSTREAM). HIGH TEMPS ON THU LOOK TO BE A FEW DEGREES WARMER THAN ON WED GIVEN THICKNESSES IN THE 1340-1360 METER RANGE...AND WILL FORECAST ABOVE NORMAL HIGH TEMPS RANGING FROM 65-69F ACROSS THE AREA. -VINCENT && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AS OF 400 AM MONDAY... A COUPLE OF WAVES IN RAPID SUCCESSION WITHIN FAST WESTERLY FLOW APPROACH LATE IN THE WEEK AND APPEAR TO ORIGINATE IN A STRONG PERTURBATION OVER THE NORTH PAC NOW BETWEEN 160-180W. THOUGH BOTH GFS AND ECMWF SHOW GENERALLY THE SAME TWO-WAVE PATTERN... CONFIDENCE REMAINS LOW FOR DETAILS ON THE TIMING AND IMPACT OF THESE DISTURBANCES ON SENSIBLE WEATHER OVER CENTRAL NC THU NIGHT THROUGH SAT NIGHT. FORECASTS WILL SHOW AN INCREASE IN CLOUDINESS THU NIGHT AND VARIABLY TO MOSTLY CLOUDY SKIES FRI THROUGH SAT THEN DECREASING CLOUDINESS SAT NIGHT INTO SUN. RAIN CHANCES WILL BE MAINLY IN THE 20-30 PERCENT RANGE FRI-SAT. TEMPERATURES SHOULD AVERAGE CLOSE TO NORMAL WITH A SOMEWHAT NARROWED DIURNAL RANGE BECAUSE OF EXPECTED CLOUDINESS. -RFG && .AVIATION /11Z MONDAY THROUGH FRIDAY/... AS OF 950 AM MONDAY... CONFLUENT WESTERLY FLOW ALOFT AND A COUPLE OF DRY COLD FRONTS LEADING DRY CONTINENTAL AIR THROUGH CENTRAL NC SHOULD MAINTAIN VFR CONDITIONS THROUGH THU NIGHT. A STRONGER SOUTHERN STREAM WAVE AND ASSOCIATED TRANSIENT LOW PRESSURE SYSTEM MAY LOWER CIGS AND VSBY TO MVFR OR IFR WITH AREAS OF RAIN FRI. -RFG && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL/VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...RFG AVIATION...RFG nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 938 PM EDT MON MAR 10 2008 .SYNOPSIS... HIGH PRESSURE RETURNS TUESDAY...FOLLOWED BY ANOTHER COLD FRONT TUESDAY NIGHT. THIS FRONT RETURNS AS A WARM FRONT WEDNESDAY NIGHT...FOLLOWED BY A YET ANOTHER COLD FRONT EARLY FRIDAY. ANOTHER LOW PRESSURE SYSTEM ARRIVES FROM THE SOUTHWEST AND MOVES ON THROUGH THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... STRONG H5 WAVE EXITING THE MTNS AS OF 1Z. IT GENERATED A SWATH OF LGT RA E OF THE OH RVR THAT TRACKED INTO THE MTNS. QPF HAS RANGED FM A HUNDREDTH AT HTS TO FIVE HUNDREDTHS IN THE CNTRL MTNS. OVERALL LIKE THE RUC13 IDEA OF PCPN EXITING BY 230Z WITH LEFTOVER RW--/SW-- IN THE NRN MTNS UNTIL MDNGT. TROF AXIS IS NEAR THE OHIO RIVER ATT BRINGING A REINFORCING SHOT OF COLD AIR AND STRATOCU. SKY FCST IS TOUGH OVERNIGHT WITH NUMEROUS BREAKS UPSTREAM IN THE BUCKEYE STATE...NOT TO MENTION CI RACING E/NE FM THE LWR MS RVR VLY. TWEAKED SKY GRIDS TO REFLECT A LONGER PD OF BKN-OVC CKB-EKN VCNTY WHILE LEAVING THE REST UNCHANGED. FOG IS CONCERN AS WELL JUST BY TAKING A LOOK OUT THE FRONT DOOR AND HILLTOP REPORTING STATIONS. VIS SHOULD BE HIGH ENOUGH TO PRECLUDE MENTION IN THE ZNS GIVEN LWR DWPTS ADVECTING FM THE NW COUPLED WITH STRATOCU FLOATING ARND MOST OF THE NGT. BEST SHOT STANDS TO BE THE SRN COAL FLDS AND MTNS WHERE HIGHEST QPF VALUES WERE OBSERVED THIS EVNG. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... WHILE THE MOISTURE ACROSS THE REGION WILL BE LIMITED THROUGH THE PERIOD...THERE ARE SEVERAL WEAK FRONTS THAT WILL BE MOVING ACROSS THE AREA TUESDAY NIGHT AND WEDNESDAY NIGHT...BUT AT THIS POINT NOT EXPECTING ANY MORE THAN LIGHT SPRINKLES OR FLURRIES. ON TUESDAY...HIGH PRESSURE SLIDES INTO THE AREA. HAVE HELD THE CLOUDS IN THE MOUNTAINS THROUGH EARLY AFTERNOON AS THE UPSLOPE FLOW LINGERS. BUT THE TEMPERATURES DO NOT GET COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH SO FOR NOW HAVE JUST GONE DRY...BUT SOME DRIZZLE/FREEZING DRIZZLE COULD LINGER THROUGH THE MORNING IN THE NORTHERN MOUNTAINS. FOR TEMPERATURES...HAVE LEANED A LITTLE COOLER TOWARD THE MET NUMBERS IN THE NORTHERN MOUNTAINS OTHERWISE GENERALLY RAN JUST UNDER THE MAV. FOR TUESDAY NIGHT...SEE A WEAK FRONT SLIDING IN FROM THE NORTHWEST. THE MOISTURE LOOKS VERY LIMITED AND WITH THE TRACK OF THE SHORTWAVE GOING NORTH OF THE AREA AND THE JET ENERGY SLIDING NW TO SE JUST NORTH OF THE REGION...SEEING TOO MANY FACTORS AGAINST PCPN. SO FOR NOW...HAVE LEFT POPS OUT ONLY MENTIONING SOME SPRINKLES OR FLURRIES ACROSS THE NORTH. LIKED THE WARMER TEMPERATURES OF THE MAV. HIGH PRESSURE RETURNS ON WEDNESDAY...AS THE FRONT STALL JUST SOUTH OF THE AREA. IT THEN RETURNS NORTH ON WEDNESDAY NIGHT...BUT AGAIN WITH THE FLOW AT 850 OUT OF THE WEST THE MOISTURE WILL BE LIMITED. AND THE MAIN DYNAMICS ARE ACROSS THE GREAT LAKES AND WILL BE LIFTING NORTH SO EXPECT TO SEE LITTLE MORE THAN CLOUDS WITH THE WARM FRONT. FOR TEMPERATURES ON WEDNESDAY AND WEDNESDAY NIGHT...AGAIN LEANED TOWARD THE MAV NUMBERS. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... COLD FRONT MOVES THROUGH THU NT AND FRI. MODELS ARE RATHER INCONSISTENT WITH THIS FEATURE EXCEPT THAT IT IS DISORGANIZED. WENT CLOSER TO FASTER GFS THAN HPC...WHICH SORT OF BLENDS THIS EVENT WITH THE LOW PRESSURE SYSTEM OVER THE WEEKEND. KEPT WEATHER DRY TO START THU FOLLOWED BY AN INCREASING CHANCE FOR SHOWERS THU AFTERNOON AND NT. AS THE FRONT LIMPS E AND WEAKENS...DECREASE POPS FRI TRYING TO DEPICT SOME SEMBLANCE OF A BREAK BETWEEN IT AND THE NEXT SYSTEM. DID ROLL WITH HPC WITH THIS SYSTEM WHICH MOVES THROUGH SAT AND SAT NT. TRACK IS UNCERTAIN AS GFS TRACKS IT JUST N OF THE AREA. HPC THOUGHT THIS WAS TOO AMPLIFIED A SOLUTION FOR THE FLAT SOUTHERN STREAM FLOW AND WENT CLOSER TO SOUTHERN TRACK OF ECMWF AND ENSEMBLES. EVEN WITH A SOUTHERN TRACK...TEMPERATURES WILL BE MARGINAL AT BEST FOR SNOW AS NORTHERN STREAM IS NOT AS MUCH OF A FACTOR AS HAS BEEN THE CASE. THEREFORE WENT MAINLY WET WITH THIS SYSTEM. TRIMMED HPC NEAR CAT POPS WITH THIS SYSTEM GIVEN LONG LEAD TIME AND UNCERTAINTY ON TRACK AND EVEN THE TIMING. THERE MAY BE SNOW ON THE BACK SIDE OF THE SYSTEM AS IT EXITS SUN. DRY WEATHER THEN ENSURES SUN NT INTO MON...WITH NEXT SYSTEM APPROACHING EARLY NEXT. AREA SHOULD BE IN RATHER MILD...STRONG S TO SW FLOW AHEAD OF THAT SYSTEM WHICH WILL TRACK WELL W OF THE AREA. RAISED HIGHS ANOTHER COUPLE OF DEGREES IN THE WARM SECTOR FLOW ON THU. LOWERED LOWS THU NT JUST A BIT...STILL ABOVE THE MEX. FOR DAYS 4 THROUGH 7 FOLLOWED HPC WITH MINOR ADJUSTMENTS...MAINLY FOR ELEVATION. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... LGT RA ASSOCIATED WITH AN UPR LVL DISTURBANCE MOVES THRU THE MTNS THEN NEXT HR OR SO. AS IT CROSSES...FLIGHT CATEGORIES WILL FALL TO MVFR. POST FRONTAL TROF AXIS SWEEPS THRU IN THE BY 3Z DROPPING CIGS TO MVFR THRU 6Z W AND 9Z MTNS. CAN NOT RULE OUT VIS RESTRICTIONS IN RIVER FG DURING THE PREDAWN...BUT FOR NOW LEFT IT GIVEN AMOUNT OF CLDS PREDICTED. MVFR STRATOCU LINGERS IN THE W/NW FLOW TUES ACR CKB/EKN BEFORE LIFTING TO VFR IN THE AFTN. CAVU IS FCST ELSW. AVIATION OUTLOOK /AFTER 0Z WED/ NO SIGNIFICANT WEATHER EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/29/ESS NEAR TERM...29 SHORT TERM...ESS LONG TERM...TRM AVIATION...29 oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 651 PM CDT MON MAR 10 2008 .UPDATE... MAIN UPDATE TO GOING FCST WAS TO INSERT AREAS OF FOG OVER THE CONCHO VALLEY, HEARTLAND, AND NORTHWEST HILL COUNTRY LATE TONIGHT AND EARLY TUESDAY. SURFACE WINDS ARE VEERING TO THE EAST LATE THIS AFTERNOON AND WILL BECOME LIGHT SOUTHEASTERLY TONIGHT. THIS WILL GRADUALLY BRING BACK THE BETTER LOW LEVEL MOISTURE OVER SOUTHERN AND EASTERN TEXAS. THIS...COMBINED WITH RADIATIONAL COOLING FROM THE MOSTLY CLEAR SKIES EXPECTED TONIGHT WILL RESULT IN FOG AND/OR LOW STRATUS DEVELOPMENT...MAINLY OVER THE SOUTHERN AND EASTERN PORTIONS OF THE FCST AREA. RUC MODEL SOUNDINGS AT KSJT AND KJCT AT 09Z TUE SUGGEST FAVORABLE HYDROLAPSES WITHIN THE LOWEST 10 TO 20 MB OF THE SOUNDING TO SUPPORT DENSE FOG IN SOME SPOTS. WILL HAVE TO MONITOR LATER TONIGHT TO SEE IF AN ADVISORY WILL BE NEEDED. LACY && .PREV DISCUSSION... /ISSUED 631 PM CDT MON MAR 10 2008/ AVIATION... MAIN ISSUES THIS TAF PACKAGE WILL BE POSSIBLE LOW CLOUDS AND SOMEWHAT LOWER VISIBILITIES LATE TONIGHT INTO EARLY MORNING ACROSS SRN HALF OF AREA...IE SOA/SJT/JCT/BBD TAFS. WITH LIGHTER WINDS AND SOME RETURN FLOW COULD SEE SOME INSTANCES. MUCH MORE WIND EXPECTED BY MID TO LATTER PORTION OF THE WEEK WITH BETTER SRLY FLOW. 11/KEISER PREV DISCUSSION... /ISSUED 316 PM CDT MON MAR 10 2008/ SHORT TERM... UPPER LEVEL TROUGH OVER WC TEXAS MOVING EAST THIS AFTERNOON... WITH CLEARING SKIES. ANY CUMULUS THIS AFTERNOON SHOULD QUICKLY DISSIPATE IN THE EARLY EVENING. WINDS WILL ALSO DECOUPLE THIS EVENING...BECOMING LIGHT AS SURFACE HIGH PRESSURE CENTERS OVER WEST CENTRAL TEXAS EARLY TUESDAY MORNING. WENT A FEW DEGREES BELOW GUIDANCE WITH GOOD RADIATIONAL COOLING TONIGHT. LONG TERM... UPPER LOW SEEN IN THE WATER VAPOR LOOP OVER COLORADO WILL MOVE ACROSS WC TEXAS TUESDAY. MAIN EFFECT WILL BE SCATTERED MID/HIGH CLOUDS. MAY SEE SOME VIRGA...BUT DRY LOWER ATMOSPHERE EVAPORATE ANY MID LEVEL SHOWERS. DRY THIS WEEK...WITH ELEVATED FIRE DANGER WEDNESDAY THROUGH FRIDAY. SURFACE LOW DEVELOPS IN THE PANHANDLE WEDNESDAY...WITH DRY PACIFIC FRONT THURSDAY. FRIDAY HAS THE MOST POTENTIAL FOR WILDFIRE DANGER...AS A SURFACE LOW MOVES FROM THE PANHANDLE MOVE SOUTHEAST ALONG THE RED RIVER DURING THE DAY FRIDAY. TOO EARLY TO TELL HOW MUCH WIND. GFS MODEL CENTERS THE SURFACE LOW NEAR HASKELL...WHICH WOULD KEEP WINDS LIGHT ACROSS MUCH OF THE BIG COUNTRY (BUT STRONG IN THE CONCHO VALLEY). IF FARTHER NORTH LIKE ON THE ECMWF MODEL...TOWARD THE RED RIVER/SOUTHERN OKLAHOMA...DRY WEST WINDS MIGHT BE SIGNIFICANTLY STRONGER IN THE 25-35 MPH RANGE ACROSS THE BIG COUNTRY. TEMPERATURES IN THE LOWER 80S WOULD JUST ENHANCE THE FIRE DANGER. WENT MORE TOWARD THE STRONGER WINDS IN THIS ZONE PACKAGE. OTHERWISE LONG WAVE UPPER TROUGH APPROACHES TEXAS EARLY NEXT WEEK. ECMWF SIMILAR TO GFS...BUT JUST A HINT FASTER. BASICALLY JUST LEFT A SLIGHT CHANCE OF THUNDERSTORMS SUNDAY INTO MONDAY...WHICH WAS ALREADY IN THE FORECAST. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 41 68 49 76 / 0 10 0 0 SAN ANGELO 41 67 43 75 / 0 0 0 0 JUNCTION 41 71 43 74 / 0 10 0 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 1014 PM CDT SUN MAR 9 2008 .UPDATE... CONVECTIVE COMPLEX ASSOCIATED WITH LEAD SHRTWV HAS MOVED EAST OF AREA WITH STRONGEST CONVECTION VCNTY STALLED FRONT STRETCHING FROM SOUTH OF MIDLAND TO NEAR WICHITA FALLS INTO SOUTH CENTRAL OK. THIS ACTIVITY SUPPORTED BY SOUTHERLY LLJ AS SEEN ON VWP/PROFILER NETWORK ACROSS WEST CENTRAL AND CENTRAL TX. TRAILING LOBE OF ENERGY WEST OF EL PASO WILL ROTATE ACROSS BIG BEND OVERNIGHT KEEPING FOCUS FOR ASCENT ACROSS THE TRANS PECOS INTO THE CONCHO VALLEY AND HILL COUNTRY. LOCALLY...OUTFLOW FROM CONVECTION HAS PUSHED HIGHER DEWPOINT AIR WESTWARD INTO SOUTHEAST CORNER. MODELS BRING THIS MOISTURE WESTWARD ALONG SOUTHERN EDGE OF CAPROCK BY MORNING DESPITE BEING OPPOSED BY MORE NORTHERLY SURFACE WINDS. AS PRESSURES FALL ALONG THE LEE OF THE ROCKIES IN RESPONSE TO NEXT SHRTWV DIVING QUICKLY SOUTHWARD ON MON...SOME OF THIS MOISTURE COULD BE PULLED NORTHWARD ACROSS THE SOUTH PLAINS. EXPECT LITTLE AFFECT ON LATER PERIODS OF FORECAST SO HAVE UPDATED NIGHTTIME PERIOD TO REDUCE POPS ACROSS SE CORNER AND BRING SLIGHTLY HIGHER DEWPOINTS/WARMER OVERNIGHT LOWS ACROSS SMALL SECTION WHERE MOISTURE HAS INCREASED. && .AVIATION... LIKELHOOD OF MVFR CIGS AT KLBB CONTINUE TO BE POSSIBLE DESIPITE PERSISTENT DRYING IN NORTHERLY SURFACE FLOW ON THE CAPROCK. SOME LOW LEVEL MOISTURE HAS BEEN ENRICHED COURTESY OF OUTFLOW FROM CONVECTIVE COMPLEXT ACROSS BIG COUNTRY. SHORT TERM MODELS NAM/RUC BRING MOISTURE WESTWARD OVERNIGHT AT 850 MB ON CONTINUED E/NE WINDS IN VERY WEAK UPGLIDE. ANY LOW CLOUD FORMATION SHOULD BE SHORT LIVED AND SCATTERED AND WITH THAT CURRENTLY IN TAF WILL LEAVE IT FOR 06Z ISSUANCE. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 24 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SPOKANE WA 1112 AM PDT SUN MAR 9 2008 .SYNOPSIS... HIGH PRESSURE WILL BE OVER THE INLAND NORTHWEST TODAY. A PACIFIC STORM SYSTEM WILL PASS THROUGH THE REGION TONIGHT THROUGH TUESDAY WITH WARMER YET WETTER CONDITIONS. A RIDGE WILL RETURN BY WEDNESDAY ...ALTHOUGH A MOIST WESTERLY FLOW WILL MOVE INTO THE REGION BY THE END OF THE WORK WEEK. && .DISCUSSION... REST OF TODAY...HIGH PRESSURE IS SITUATED AT THE SFC (CENTERED OVER IDAHO/GREAT BASIN AREA). COUPLED WITH A MOIST BL (UP TO ABOUT 900 MB)...A LIGHT SE FLOW AT THE SFC AND WEAK WAA AT 850 HELPING TO MAINTAIN AN INVERSION....THIS SET-UP LED TO THE DEVELOPMENT STRATUS AND FOG (LOCALLY DENSE) A LITTLE PAST MIDNIGHT ACROSS PORTIONS OF THE SPOKANE/C`DA AREA AND SOME NRN VALLEYS...AS WELL AS ACROSS THE L-C AREA. THE MOIST LAYER IS ABOUT 400-500 FEET DEEP. THE NAM AND RUC MODEL SOUNDINGS (WHICH INITIALIZED WELL COMPARED TO THE 12Z SOUNDING) INDICATE THE INVERSION BREAKING TOWARD 18Z AND BETTER MIXING TO BREAK UP THIS FOG/STRATUS. SOME OF THE DEEPER VALLEYS MAY TAKE UNTIL LATE AFTERNOON TO COMPLETELY LIFT OUT THE STRATUS. HOWEVER MID TO HIGH CLOUDS ARE STREAMING IN ALOFT. ON LARGER A SCALE...A LONG-WAVE TROUGH IN THE GULF OF AK HAS THE PACIFIC NW IN A WSW FLOW. A STREAM OF MOISTURE AND A COUPLE SHORT-WAVE SYSTEMS ARE PIVOTING AROUND THAT FEATURE. ONE SHORT-WAVE IS SLIPPING INTO BC. MID AND HIGH MOISTURE AND ASSOCIATED CLOUDS ARE SPREADING IN FROM THE WEST WITH THIS FEATURE. MOST OF THE SYNOPTIC SCALE LIFT ASSOCIATED WITH THE SHORT-WAVE REMAINS NORTH OF THE CANADIAN BORDER. AN ELONGATED/WEAK VORT MAX WAS PASSING EAST OF THE CASCADES AND A SECOND WEAK VORT MAX ONTO THE WA COAST TOWARD 00Z. THIS COMES WITH SOME DEEPENING ON MOISTURE INTO THE CASCADES AND SOME ISENTROPIC ASCENT AS A WARM FRONT STARTS TO LIFT NORTH. THIS WILL MEAN A SLIGHT CHANCE FOR SHOWERS NEAR THE CASCADES LATE. OTHERWISE THE REST OF TODAY WILL BE DRY. TEMPERATURES ARE RUNNING BELOW GUIDANCE AND FORECAST. VALUES WERE CUT BACK 2-3 DEGREES /J && .AVIATION... FOG/STRATUS WILL LIFT TO MAINLY VFR/LCL MVFR CIGS SUNDAY AFTERNOON. THE NEXT SYSTEM MOVING IN TONIGHT AND MONDAY WILL BRING IN MID/HIGH CLOUDS...GRADUALLY LOWERING BY LATE AM TO MIDDAY MONDAY. HOWEVER...PRIMARILY VFR CONDITIONS FCST TO 18Z. RISK FOR LIGHT PRECIP WILL BEGIN TO SPREAD IN FROM THE WEST AFTER 12-15Z...WITH LCL MVFR CIGS WITH PRECIP. /J && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 49 37 53 42 46 29 / 0 0 20 80 40 20 COEUR D`ALENE 46 35 53 42 46 29 / 10 0 20 80 60 30 PULLMAN 52 38 56 44 48 31 / 0 0 10 80 50 20 LEWISTON 57 40 63 47 54 35 / 0 0 10 80 50 10 COLVILLE 50 34 50 39 46 28 / 0 10 40 70 40 20 SANDPOINT 47 33 49 40 46 29 / 10 10 30 80 60 40 KELLOGG 46 34 55 41 47 30 / 10 0 20 90 60 50 MOSES LAKE 56 39 55 41 55 31 / 0 0 30 40 10 10 WENATCHEE 52 39 52 42 55 33 / 0 10 30 40 10 10 OMAK 51 34 50 38 53 26 / 0 20 50 50 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 252 PM CDT SUN MAR 9 2008 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT FORECAST CONCERNS ARE ON SNOW CHANCES TONIGHT AS WELL AS CLOUD TRENDS...THEN TEMPERATURES THROUGH WEDNESDAY. 18Z SURFACE ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE NEAR KDBQ WITH A TRAILING COLD FRONT SOUTH INTO NORTHERN MISSOURI. MEANWHILE A TROUGH OF LOW PRESSURE STRETCHES FROM THE LOW NORTHWEST ACROSS THE FORECAST AREA AND INTO SOUTHERN MINNESOTA. THIS TROUGH HAS BEEN THE FOCUS FOR VERY LIGHT SNOW AND FLURRIES ACROSS THE AREA TODAY. 09.12Z SHORT RANGE MODELS IN GOOD AGREEMENT THROUGH THE PERIOD. GFS CONTINUES TO HAVE MORE MOISTURE AND RESULTANT QPF ON TUESDAY AS A SHORT WAVE TROUGH MOVES ACROSS NORTHERN MINNESOTA/WISCONSIN INTO THE GREAT LAKES. IT IS THE ONLY ONE WITH QPF INTO THE AREA AND THUS DISCOUNTING THIS SOLUTION. IN THE NEAR TERM...BOTH THE GFS/NAM AS WELL AS THE RUC SHOWING VERY WEAK QG CONVERGENCE THIS EVENING ALONG THE TROUGH ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. ALL THE MODELS CONTINUE TO SHOW VERY LIGHT QPF IN THIS REGION. HOWEVER...WITH LATEST RADAR TRENDS HAVE BACKED OFF TO JUST FLURRIES THROUGH THE EVENING HOURS. NEXT QUESTION IS CLOUDS. SATELLITE TRENDS SHOWING QUITE A FEW HOLES IN THE CLOUDS OVERHEAD WITH CLEARING SKIES ALREADY TAKING PLACE ACROSS THE NORTHERN ZONES.. MODEL RELATIVE HUMIDITY TRENDS SHOW A SLOW DECREASE IN THE CLOUDS OVERNIGHT AS THE TROUGH SAGS SOUTHWARD. HIGH PRESSURE THEN DOMINATES THE WEATHER MONDAY AND MONDAY NIGHT WITH QUIET WEATHER EXPECTED. A SHORTWAVE MOVES ACROSS NORTHERN MINNESOTA AND NORTHERN WISCONSIN TUESDAY...BUT MOISTURE VERY LIMITED SO ANY PRECIPITATION WILL REMAIN WELL NORTH OF THE AREA. AS THE HIGH SLIDES SOUTHEAST OF THE AREA WARM ADVECTION WILL BEGIN... DRAWING WARMER AIR BACK INTO THE REGION FOR TUESDAY AND WEDNESDAY. 850MB TEMPERATURES WARM TO THE PLUS SIDE OF ZERO AND WITH A DECENT AMOUNT OF SUN WILL SEE TEMPERATURES REBOUND BACK TO NEAR OR SLIGHTLY ABOVE SEASONAL NORMALS FOR BOTH TUESDAY AND WEDNESDAY. GUIDANCE VALUES SHOWING ALL AREAS TO RISE INTO THE 40S BOTH DAYS. WITH THE CLEAR SKIES OVERNIGHT LOWS WILL DROP BACK BELOW THE FREEZING MARK SO MELTING TEMPERATURES TO BE CONFINED TO DAYTIME HOURS. .LONG TERM...THURSDAY THROUGH SUNDAY MEDIUM RANGE MODELS IN DECENT AGREEMENT WITH THE OVERALL PATTERN THROUGH THIS PERIOD. NORTHWEST FLOW TO DOMINATE THROUGH SATURDAY BEFORE LARGE TROUGH PUSHES INTO THE WESTERN CONUS...BUCKLING THE FLOW ACROSS THE CENTRAL CONUS. ENSEMBLES AND DETERMINISTIC 09.06Z GFS AND 09.00Z ECMWF SHOW SHORTWAVE ADVANCING ALONG THE CANADIAN BORDER ON THURSDAY...DRAGGING A COLD FRONT ACROSS THE GREAT LAKES... WHICH WILL USHER IN ANOTHER SHOT OF COOLER AIR FOR THE WEEKEND. THERMAL PROFILES INDICATE SOME WARMER AIR BEING ADVECTED INTO THE AREA THURSDAY AND THURSDAY NIGHT AND WILL CONTINUE TO MENTION RAIN OR SNOW CHANCES...ALBEIT ANY PRECIPITATION THAT FALLS LOOKS TO BE IN THE LIGHT SIDE. RABERDING && .AVIATION... AN INVERTED TROUGH CONTINUES TO RESIDE ACROSS SOUTHEAST MINNESOTA... NORTHEAST IOWA...AND THE SOUTHERN HALF OF WISCONSIN. THIS TROUGH WAS PRODUCING A SCATTERED TO BROKEN MVFR DECK /1500 TO 2500 FEET/ AND SCATTERED SNOW SHOWERS WHICH REDUCED VISIBILITIES TO 3 MILES IN A FEW PLACES. THE 09.12Z MODELS CONTINUE TO SHOW THAT THIS TROUGH WILL MOVE SLOWLY SOUTHEAST OUT OF THE AREA ON MONDAY MORNING. AS THIS OCCURS...THE FLOW WILL GRADUALLY BECOME ANTICYCLONIC AND THE CLOUDS WILL GRADUALLY BREAK UP. AT THIS TIME...IT LOOKS LIKE THIS SHOULD OCCUR BETWEEN 10Z AND 14Z MONDAY. HOWEVER...I AM A BIT CONCERNED THAT THIS MAY BECOME SOONER...BECAUSE THERE ARE SOME HOLES IN THE CLOUDS. ONCE THESE CLOUDS BREAK UP...WE SHOULD VFR CONDITIONS THROUGH THE REMAINDER OF MONDAY. BOYNE && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ wi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 530 AM EDT TUE MAR 11 2008 .SHORT TERM /TODAY THROUGH THURSDAY/... LATEST SURFACE MAP SHOWS A WEAK SURFACE BOUNDARY ACROSS THE MIDDLE OF THE FORECAST AREA THIS MORNING. BACK TO THE WEST...A SHARP UPPER SHORTWAVE OVER EAST TX IS DRIVING AN AREA OF MID LEVEL CLOUDS AND LIGHT RAIN...CURRENTLY OVER LA/MS...EASTWARD. THE GFS BRINGS AMPLE CLOUDS AND LIGHT MEASURABLE PRECIP OVER THE AREA TODAY...WHILE THE NAM SHOWS A RELATIVELY DRY EVENT WITH MUCH WARMER HIGHS. HAVE LEANED TOWARD THE WETTER AND COOLER GFS SOLUTION...BUT HELD POPS DOWN TO ONLY A SLIGHT CHANCE. THE DISTURBANCE AND ASSOCIATED CLOUDS/RAIN PUSH EAST OF THE AREA BY EARLY EVENING...WITH WEAK RIDGING THEN DOMINATING THE REST OF THE SHORT TERM. AFTER TODAY...MAV AND MET NUMBERS ARE CLOSE AND LOOK REASONABLE SO DID NOT STRAY FAR. .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE GFS...DGEX AND UKMO ARE IN MUCH BETTER AGREEMENT WITH TIMING AND STRENGTH OF NEXT WEATHER SYSTEM PROGD TO TRAVERSE THE AREA ON SATURDAY. THE ECMWF LOOKS WAY TOO FAST. WILL LEAN TOWARD THE GFS SOLUTION WHICH SHOWS A SHARP SHORTWAVE DRIVING A SURFACE LOW AND ASSOCIATED FRONTAL BOUNDARY ACROSS THE TN AND OHIO VALLEYS ON SATURDAY. A WARM/MOIST SOUTHERLY FLOW OUT AHEAD WILL WARRANT A CHANCE OF SHOWERS ON FRIDAY...BUT THE GREATER RAIN CHANCES WILL BE ON SATURDAY WITH THE FRONTAL PASSAGE. MAIN CONCERN IS THE INCREASE IN INSTABILITIES ON SATURDAY...NOW SHOWING 1000-1500 CAPES AND -4 TO -7 LI`S ACROSS THE ENTIRE FORECAST AREA BY 18Z SATURDAY. THIS COUPLED WITH A 50KT LOW LEVEL JET WILL WARRANT MENTION OF SCATTERED THUNDERSTORMS ON SATURDAY...AND A FEW COULD BE STRONG. EXPECT THE STRONGER STORMS TO BE NORTH OF THE AREA...WHERE THE UPPER SHORTWAVE AND SURFACE LOW TRACK. HOWEVER...A FEW STRONG AND POSSIBLY SEVERE STORMS CANNOT BE RULED OUT...ESPECIALLY SATURDAY AFTERNOON JUST AHEAD OF THE FRONT. AT THIS TIME...IT APPEARS THE GREATER STORM THREAT WOULD BE GENERALLY ALONG AND NORTH OF A COLUMBUS TO MILLEDGEVILLE LINE ON SATURDAY. THE COLD FRONT SWEEPS THRU LATE SATURDAY WITH DIMINISHING RAIN CHANCES DURING THE EVENING...EXCEPT SOME PATCHY WRAP AROUND LIGHT RAIN IN THE MOUNTAINS SATURDAY NIGHT-SUNDAY MORNING. APPEARS TEMPS WONT BE COLD ENOUGH TO BRING ANY WINTRY THREAT TO THE MOUNTAINS...BUT WILL WATCH THIS CLOSELY. OTHERWISE...A COOL DOME OF HIGH PRESSURE SETTLES OVER THE AREA FOR SUNDAY AND MONDAY. && .FIRE WEATHER... A DRY AIRMASS SETTLES IN OVER THE REGION ON WEDNESDAY...WITH AFTERNOON RH VALUES DIPPING AT OR BELOW THE CRITICAL 25% OVER MAINLY THE EAST CENTRAL PORTIONS OF THE FORECAST AREA WEDNESDAY AFTERNOON. WITH SOME UNCERTAINTY ABOUT THE 4 HOUR DURATION AND FUEL MOISTURES... WILL LET DAY SHIFT TAKE A LOOK AT THE NEXT MODEL RUN AND POST A WATCH FOR WEDNESDAY AFTERNOON IF CONDITIONS WARRANT. STAY TUNED. && .AVIATION... VFR EXPECTED TO PREVAIL AT THE FFC TAF SITES AGAIN TODAY. TWO WEAK UPPER TROUGHS...ONE IN THE NORTHERN STREAM MOVING ESE FROM THE OHIO VALLEY TOWARD THE MID-ATLANTIC...AND ANOTHER IN THE SOUTHERN STREAM MOVING EASTWARD FROM TX...WILL MINIMALLY IMPACT THE REGION TODAY IN THE FORM OF MID CLOUDS. A WEAK FRONT WILL FOLLOW THE UPPER SHORT WAVE OVERNIGHT. CEILINGS...AREA OF MID CLOUDS ASSOCIATED WITH THE SOUTHERN STREAM SHORT WAVE WILL SPREAD ACROSS THE AREA TODAY. SYSTEM IS FAST MOVING...SO EFFECTS SHOULD CONFINED PRIMARILY TO THE 12Z-00Z PERIOD. EXPECT BKN-OVC CIGS MAINLY IN THE 070-090 RANGE. SOME SCT050 POSSIBLE IN THE AFTERNOON. SKC SHOULD QUICKLY RETURN AFT 00Z TO ALL TAF SITES AS MEAN RH DROPS TO 20 PERCENT OR LESS. VISIBILITY...RADIATIONAL COOLING CONDITIONS NOT AS OPTIMAL AS THE PAST TWO MORNINGS WITH INCREASED MID CLOUD COVER. ALL SITES STILL VFR AT 09Z. STILL...THOUGH...CANNOT RULE OUT BRIEF MVFR BR...ESPECIALLY FOR MCN-AHN...WHERE MID CLOUDS NOT QUITE AS THICK YET AND T/TD SPREAD THREE DEGREES OR LESS. OTHERWISE...VFR...WITH POTENTIAL FOR MVFR BR WED MORNING TOO UNCERTAIN TO PROG THIS FAR IN ADVANCE. WX...CANNOT RULE OUT A FEW SPRINKLES...ESPECIALLY IN THE CSG-MCN AREA...BUT ANY PCPN WILL FALL FROM MID CLOUDS AND NOT EXPECTED TO IMPACT VSBY OR CIGS. WIND...AS WITH THE PAST TWO MORNINGS...VERY WEAK WIND FIELD NOTED ACROSS THE AREA. WEAK SFC TROUGH DRAPED ACROSS THE AREA FROM NE-SW RIGHT OVER THE ATL AREA...RESULTING IN MOSTLY CALM WINDS. VAD PROFILE SHOWS SSE FLOW JUST OFF THE SFC...WHICH GFS AND RUC BOTH HINT AT FOR THE FIRST COUPLE OF HOURS OF TAF VALID PERIOD. AS THE DAY PROGRESSES...SFC TROUGH SHIFTS EAST AND HIGH PRESSURE BEINGS TO BUILD SE FROM THE MIDWEST. EXPECT A WEST FLOW TO RESUME. CALM OR VRB03KT WILL GIVE WAY TO 280-320 5-7KT BY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 64 37 72 40 75 / 20 5 5 5 10 ATLANTA 62 39 67 45 73 / 20 5 5 5 10 BLAIRSVILLE 57 29 65 36 68 / 20 5 5 5 10 CARTERSVILLE 60 33 67 36 72 / 20 5 5 5 10 COLUMBUS 63 38 71 41 75 / 20 5 5 5 10 GAINESVILLE 62 38 69 44 70 / 20 5 5 5 10 MACON 64 36 71 38 76 / 20 5 5 5 10 ROME 61 34 71 40 77 / 20 5 5 5 10 PEACHTREE CITY 63 34 69 36 74 / 20 5 5 5 10 VIDALIA 69 40 71 39 74 / 20 10 5 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 39/19 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 423 AM EDT TUE MAR 11 2008 CORRECTED TO FIX TYPO .SHORT TERM (TODAY AND TONIGHT)... SFC HIGH IN CONTROL OF THE REGION THIS MORNING...CENTERED JUST EAST OF STL AS OF THIS WRITING. NORTHWEST FLOW ALOFT WITH TROUGH AXIS NEAR OR ACROSS THE EASTERN COASTLINE. SKIES BEGAN TO CLEAR OVERNIGHT ALLOWING FOR DECENT RAD COOLING FOR MOST OF THE REGION...AND IN COMBO WITH LIGHT WINDS AND AMPLE LOW LEVEL MOISTURE HAVE CREATED STRONG CONDITIONS FOR FOG DEVELOPMENT EARLY THIS MORNING. WILL CONTINUE TO MONITOR FOR ANY SIGNIFICANT DROPS IN VSBY...ESPECIALLY ACROSS THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA. THE LATEST RUC 13 RUN WOULD SUGGEST THAT VSBYS WOULD NEAR DENSE FOG CRITERIA BY 10Z...WILL WATCH THE CLEARING OF THE CLOUDS...TIMING...AND VSBY DROPS AFTERWARD TO SEE IF A DENSE FOG ADVISORY WILL BE NEEDED LATER THIS MORNING. GFS APPEARS TO HAVE WAY TOO MUCH MOISTURE WITH THE FAST MOVING CLIPPER-LIKE SYSTEM THAT DRIVES THROUGH THE GREAT LAKES THIS EVENING AND OVERNIGHT. THE DRIER NAM MOISTURE FIELDS SEEM A BETTER FIT AS THE SYSTEM HAS NO WAY TO TAP THE GULF. EXPECT NEAR FULL SUN FOR THIS MORNING INTO THE EARLY AFTN...MOST IF NOT ALL OF THE REMAINING SNOWPACK SHOULD BE RELEASED IN THE NEXT 24HRS. THE SNOWPACK HAD LITTLE AFFECT ON TEMPS TODAY WITH HIGHS IN THE LOWER 40S WHERE SNOW LIES...WITH THE INCREASING SUN ANGLE HAVE NOT ACCOUNTED FOR THE OLDER SNOWFIELD COOLING AS MUCH AS NORMALLY WOULD. MOS EQUATIONS MAY STILL BE USING WINTER SCHEME...AND WOULD NOT ACCOUNT FOR THE STRONGER MID MARCH SUN ANGLE AS WELL...ANOTHER REASON TO GO ABV MOS IN THE SOUTHEAST...THE SOUTHWEST WINDS WILL HELP IN THIS MATTER AS WELL WITH MID 40S OR HIGHER ACROSS MUCH OF THE FORECAST AREA. MID AND UPPER LEVEL CLOUDS ASSOCIATED WITH THE SYSTEM MOVING TO THE NORTH AND EAST OF THE REGION IN THE EVENING. WEAK SFC TROUGH PUSHING THROUGH AFTER MIDNIGHT...WITH JUST A WIND SHIFT TO THE NORTH. EVEN WITH THE NORTH WINDS IN THE EARLY MORN...LOWS WILL BE NEAR NORMAL IN THE UPPER 20S. && .LONG TERM (WEDNESDAY THROUGH MONDAY)... TEMPERATURES WILL CONTINUE TO MODERATE INTO THURSDAY AS SOUTH TO SOUTHWEST WINDS INCREASE AHEAD OF AN APPROACHING SURFACE LOW AND FRONT. HIGHS SHOULD BE ABLE TO REACH NEAR 50F WITH LOW LEVEL FLOW 40 TO 50 KNOTS. KEPT A CHANCE FOR RAIN LATE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THE FRONT SHOULD REACH THE AREA EARLY THURSDAY...AND THEN A WAVE SHOULD DEVELOP ALONG THE FRONT OVER MISSOURI AND MOVE EAST THURSDAY NIGHT. OVERALL THE GFS HAS BACKED OFF BRINGING MUCH COLDER AIR BEHIND THE FRONT THURSDAY NIGHT IN LIEU OF THE WAVE ALONG THE FRONT. THEREFORE...ADDED A MIX OF RAIN AND SNOW LATE THURSDAY NIGHT. THERMODYNAMIC PROFILES CLOSE TO A RAIN AND SNOW MIX. PLACED HIGHER RAIN/SNOW CHANCES OVER SOUTHEAST AREAS WHERE BEST FRONTAL LIFT WILL OCCUR...SO BEST CHANCE FOR RAIN BASICALLY MARION TO LIMA. A SECOND LOW SHOULD MOVE EAST NORTHEAST ALONG THE FRONT SATURDAY. THE BIG CHALLENGE HERE IS HOW FAR NORTH THE PRECIPITATION WILL SPREAD. RAISED SNOW CHANCES TO 50 PERCENT IN THE SOUTH...WITH 25 TO 30 PERCENT IN THE NORTH. A LARGE ANTICYCLONE OVER SOUTH CENTRAL CANADA SHOULD HELP WITH DRY AIR ENTRAINMENT AS A COLD AND DRY NORTHEAST FETCH SETS UP OVER THE GREAT LAKES. && .PREV DISCUSSION... /ISSUED 140 AM EDT TUE MAR 11 2008/ AVIATION (06Z TAFS)... MAINLY VFR CONDITIONS ACROSS THE REGION...WITH KAOH AND KBEH THE ONLY SITES WITH MVFR OR IFR CONDITIONS. WITH CLEARING SKIES...AMPLE LOW LEVEL MOISTURE...AND LIGHT WINDS FOG WILL START TO DEVELOP REGION WIDE THROUGH THE OVERNIGHT. MVFR TO IFR CONDITIONS WILL BE POSSIBLE...AND AT BOTH MAIN TERMINAL SITES FWA AND SBN AFTER 08Z THRU DAYBREAK(14Z). WINDS WILL START TO INCREASE FROM THE WSW LATE MORNING...WITH GUSTS ABV 15KTS. WINDS WILL AGAIN LESSEN WITH HIGH LEVEL CLOUDS OVERTAKING THE REGION THIS EVENING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...SCHOTT LONG TERM...SKIPPER AVIATION...SCHOTT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 352 AM CDT TUE MAR 11 2008 .DISCUSSION... ALTHOUGH THERE WILL STILL BE SOME LATITUDINAL VARIATION/A.K.A PLAY/ THE IN THE NUMERICAL MODEL DEPICTION OF THE EVENTUAL BAROCLINIC ZONE ACROSS THE WFO PAH FORECAST AREA ON THURSDAY AND BEYOND...THE 00Z TUESDAY RUNS OF THE 12KM NAM/40KM GFS WERE QUITE SIMILAR IN THE DEVELOPMENT AND LOCATION OF A SURFACE LOW/WARM FRONTAL BOUNDARY IN THE AREA LATER THIS WEEK. HOWEVER...INITIALLY...THE RUC...THEN THE GFS APPEARED TO HAVE THE BEST HANDLE ON HEIGHT FIELDS ASSOCIATED WITH THE SHORTWAVE RIPPLES OVER CO/OK THIS EVENING. THE LIFT AHEAD OF THE LEAD SHORTWAVE OVER OK HELPED TO PRODUCE THE CIRRUS SHIELD OVER THE WFO PAH FORECAST AREA OVERNIGHT AND WAS DEPICTED WELL BY THE RUC...AND TO A MUCH LESSER EXTENT BY THE SREF/NAM/GFS. IN THE SHORT TERM...THE SHORTWAVES SHOULD SHEAR OUT AS THEY MOVE OVER THE WFO PAH FORECAST AREA...BUT HAVE LITTLE IMPACT ON THE SENSIBLE WEATHER EXCEPT TO BRIEFLY ENHANCE THE S/SWLY SURFACE WIND SPEEDS TODAY. A LOW AMPLITUDE RIDGE WILL BRIEFLY MOVE IN TONIGHT...THEN BECOME DAMPENED ON WEDNESDAY...AS THE NEXT SHORTWAVE FROM THE WEST COAST RIDES OVER THE RIDGE. SIGNIFICANT WARM AIR ADVECTION WILL WORK INTO THE AREA BY WEDNESDAY AFTERNOON...PRODUCING ABOVE NORMAL TEMPERATURES IN THE 60S ACROSS THE WFO PAH FORECAST AREA. BOTH THE NAM AND GFS DEVELOP A WEAK AREA OF LOW PRESSURE OVER MO LATE WEDNESDAY/WEDNESDAY NIGHT. A MORE DOMINANT AREA OF LOW PRESSURE DEVELOPS OVER WESTERN OK EARLY THURSDAY...WITH A WEAK SURFACE TROUGH/WARM FRONT DEVELOPING TO THE NORTHEAST TOWARD THE LESSER AREA OF LOW PRESSURE OVER NRN IL/NWRN IN. THE NAM AND GFS DIFFER IN THE STRENGTH AND PERSISTENCE OF THE NORTHERN IL LOW PRESSURE CENTER...BUT THE MAIN FACTOR INFLUENCING THE WEATHER OVER THE WFO PAH FORECAST AREA IS THE WARM FRONTAL ZONE WHICH DEVELOPS OVER SRN MO/W CNTRL IL EARLY THURSDAY. WITH MOISTURE ADVECTION FROM TX/WRN GULFMEX...MOISTURE CONVERGENCE AND DIFFERENTIAL HEATING ALONG THIS BOUNDARY WILL SUPPORT THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE WFO PAH FORECAST AREA ON THURSDAY. THE LATEST RUNS OF THE GFS/NAM HAVE BEEN MORE GENEROUS THAN PREVIOUS MODEL RUNS WITH INSTABILITY IN THE 850-500 MB LAYER ACROSS THE BOUNDARY...SUPPORTING A GREATER MENTION OF THUNDERSTORMS THAN PREVIOUSLY FORECAST. HOWEVER...THE GRADIENT OF INSTABILITY WILL BE FAIRLY TIGHT...RESTRICTED CLOSE TO THE SURFACE-850 MB FRONTAL BOUNDARY. GIVEN THE UNCERTAINTY IN THE POSITION OF THIS BOUNDARY FURTHER INTO THE FORECAST...I ADDED A 25-50NM BUFFER ZONE TO ALLOW FOR A SLIGHTLY LARGER COVERAGE OF THUNDERSTORM ACTIVITY IN TIME AND SPACE THURSDAY AND THURSDAY NIGHT. THE BAROCLINIC ZONE ACROSS THE WFO PAH FORECAST AREA REMAIN QUITE ACTIVE FROM THURSDAY THROUGH SUNDAY...SO A PERIODIC MENTION OF SHOWER AND THUNDERSTORM ACTIVITY REMAINS WARRANTED. NO CHANGES/MODIFICATIONS WERE MADE BEYOND SATURDAY NIGHT WITH THIS PACKAGE. && .AVIATION... SURFACE HIGH PRESSURE SETTLING OVER THE AREA FROM THE NORTH HAS CREATED CALM OR NEAR CALM WINDS EARLY THIS MORNING. WITH ONLY SOME THINNING CIRRUS IN THE SOUTHERN HALF OF THE AREA...SCATTERED MVFR FOG WILL BE LIKELY THROUGH 14Z THIS MORNING...WITH THE GREATEST COVERAGE IN THE NORTHERN HALF OF THE AREA. A SOUTHWEST WIND LESS THAN 10 KTS WILL DEVELOP OVER THE ENTIRE REGION BY MIDDAY...AND PERSIST THROUGH TONIGHT. SKIES WILL REMAIN MOSTLY CLEAR TODAY AND TONIGHT. SOME SCATTERED MID AND HIGH CLOUDS MAY FLIRT WITH THE KEVV AND KOWB AREAS TONIGHT...AS A CLIPPER SYSTEM DIVES SOUTHEAST THROUGH THE GREAT LAKES TOWARD THE MID-ATLANTIC COAST. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ SHORT/LONG TERM...SMITH AVIATION...DRS ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 342 AM EDT TUE MAR 11 2008 .DISCUSSION...LARGE SCALE PATTERN LOOKING PROGRESSIVE THIS WEEK WITH A BROAD 4-5 WAVE HEMISPHERIC PATTERN. REMNANTS OF A COUPLE PACIFIC ORIGIN SHORT WAVE TROUGHS WILL SWING THROUGH THE WESTERN GREAT LAKES OVER THE NEXT SEVERAL DAYS...ONE TODAY COMING OUT OF MANITOBA THIS MORNING...AND A SECOND WAVE COMING ONSHORE THIS MORNING LOOKS TO IMPACT THE AREA IN THE THURSDAY TIME FRAME. BEYOND THAT PATTERN BECOMES BASICALLY SPLIT/ZONAL FOR THE WEEKEND...SOME HINTS AT A -NAO TYPE PATTERN DEVELOPING WITH RISING HEIGHTS ACROSS ICELAND/GREENLAND...BUT PROBABLY IN NAME ONLY AS THE TYPICAL RESPONSE OVER NORTH AMERICA (E.G., COLD FOR US) DOES NOT APPEAR TO BE IN THE CARDS WITH POLAR VORTEX BOTTLED UP ABOVE 60N...AND A POSSIBLE RE-APPEARANCE OF THE SOUTHEAST U.S. RIDGE AS HEIGHTS FALL ACROSS THE SOUTHWESTERN STATES. A PROBABLE SET UP FOR MORE COMPLICATED FORECAST ISSUES NEXT WEEK. IN THE MEANTIME...HIGH PRESSURE SINKING SOUTH OF THE STATE THIS MORNING...WITH HEIGHT FALLS ASSOCIATED WITH MANITOBA SHORT WAVE/JET STREAK DIVING TOWARD THE WESTERN LAKES. SURFACE PRESSURES FALLING IN RESPONSE TO THIS (3-4MB/3H PRESSURE FALLS ACROSS WESTERN ONTARIO/NORTHERN MN)....ALLOWING ASSOCIATED SURFACE LOW OVER EASTERN MANITOBA TO DROP SOUTHEAST TOWARD LAKE SUPERIOR. SURFACE LOW FORECAST TO SLIDE ACROSS LAKE SUPERIOR TODAY...WHILE MAIN SHORT WAVE ENERGY COMES RIGHT ACROSS THE LOWER PENINSULA. SO FIRST FORECAST PROBLEM THIS MORNING WILL DEAL WITH PRECIPITATION POTENTIAL WITH THIS SYSTEM. DEEP LAYER RIDGING BUILDS INTO THE WESTERN LAKES FOR WEDNESDAY...THEN NEXT SERIES OF HEIGHT FALLS ARRIVES WEDNESDAY NIGHT/THURSDAY...WHICH IS FORECAST PROBLEM NUMBER TWO. TODAY/TONIGHT...HIGH CLOUDS INVADING NORTHERN MI EARLY THIS MORNING FROM THE NORTHWEST AHEAD OF APPROACHING SHORT WAVE TROUGH. CLOUD TOPS HAVE BEEN COOLING/EXPANDING ACROSS MN AND WESTERN ONTARIO...AND STARTING TO GET INCREASING MOISTURE IN 900-500MB LAYER PER GOES SOUNDER WATER VAPOR IMAGERY. BUT MUCH OF THAT MOISTURE LIKELY ABOVE 700MB WITH JUST A HANDFUL OF OBSERVATIONS OF CLOUDS BELOW 12K FEET THROUGH 06Z (MOSTLY ACROSS ONTARIO). A FEW HIGH BASED RADAR RETURNS HEADED INTO LAKE SUPERIOR PER ONTARIO RADAR COMPOSITE...BUT NO PRECIPITATION AT THE ONSET OF THE FORECAST PERIOD. FORECAST PROBLEM OF THE DAY IS TIMING OF INCREASED SATURATION AS STRONGER DYNAMICS COME INTO PLAY (GOOD QG FORCING AND LFQ JET DYNAMICS). LIFT IS NOT THE PROBLEM...THE QUESTION WILL IT BE ENOUGH TO MOISTEN WHAT IS ADMITTEDLY A RELATIVELY DRY ANTECEDENT AIR MASS. GUIDANCE IS STILL SPLIT ON THIS ISSUE...WITH THE NAM REMAINING DRY (SHUNTING BEST DEEP LAYER MOISTURE QUICKLY EAST OF THE FORECAST AREA THIS MORNING)...AND THE GFS SHOWING BETTER MOISTENING WITH TIME AS STRONGER FORCING ARRIVES. ECMWF/UKMET/RUC THROWING SUPPORT TOWARD THE GFS...AND AS WATER VAPOR IMAGERY SHOWS UPSTREAM WAVE TAKING ON A BETTER ORGANIZED (LESS SHEARED) APPEARANCE...GETTING COLDER CLOUD TOPS NOW DEVELOPING IN THE VICINITY OF LAKE WINNIPEG. GIVEN THE STRENGTH OF THE FORCING HAVE TO BELIEVE THAT DEEP LAYER RH WILL IMPROVE THROUGH THE DAY TO SUPPORT A THREAT OF PRECIPITATION ACROSS THE ENTIRE FORECAST AREA... THOUGH SEE NO NEED TO CHANGE OUR POP DISTRIBUTION WHICH HAS BEEN CONSISTENTLY HIGHER TO THE NORTH. NOT EXPECTING PRECIP CHANCES ACROSS NORTHERN LOWER UNTIL THE AFTERNOON. LAPSE RATES EXPECTED TO BE FAIRLY STEEP ABOVE 750MB...SUPPORTING THE POSSIBILITY OF SOME ELEVATED CONVECTIVE/SHOWERY ELEMENTS DEVELOPING. PRECIP TYPE WILL DEPEND ON DEPTH OF SURFACE BASED WARM LAYER...NAM TRYING TO SHOVE A PRETTY DECENT THERMAL RIDGE INTO THE FORECAST AREA LATER TODAY (925MB TEMPERATURES 4-6C WARMER THAN GFS)...THIS LOOKS OVERDONE BASED ON INITIALIZATION AND 05Z AIRCRAFT SOUNDING OUT OF MPX WHICH INDICATED A 925MB TEMP OF +2C WHEN THE NAM HAD +5C PROGGED AT 06Z. SURFACE TEMPERATURES SHOULD WARM IN TO THE MID 30S AT LEAST...CURRENT FORECAST IS ALL SNOW EVERYWHERE AND THINK THAT`S THE WAY TO GO AT THIS TIME. WILL CONTINUE WITH THE IDEA OF SNOW SHOWERS TAPERING OFF FROM WEST TO EAST DURING THE EVENING HOURS. WEDNESDAY...RIDGING AT THE SURFACE AND ALOFT BUILD IN WEDNESDAY IN THE WAKE OF TODAY`S SYSTEM. SHOULD BE A NICE DAY WITH TEMPERATURES NEAR OR A BIT COOLER THAN TODAY (THE LATTER BEING ESPECIALLY TRUE THE FARTHER NORTH YOU GO). NEXT SYSTEM TO IMPACT THE REGION ARRIVES WEDNESDAY NIGHT AS A SHORT WAVE TROUGH CROSSES THE NORTHERN PLAINS AND INTO THE WESTERN GREAT LAKES THURSDAY MORNING. THIS WILL INCREASE THE THREAT FOR SNOW FROM WEST TO EAST. SOME QUESTION ABOUT PRECIP TYPE BUT THIS FAR OUT WILL KEEP IT SIMPLE (AND ALL SNOW). MARINE ISSUES...WILL CARRY SMALL CRAFT ADVISORIES TODAY THROUGH THIS EVENING ON THE LAKE MICHIGAN SIDE...AND THIS AFTERNOON AND EVENING ON LAKE HURON. NO HEADLINES ANTICIPATED BEYOND TONIGHT. EARLY EXTENDED PERIODS (THURSDAY THROUGH SATURDAY)...GUIDANCE HAS BEEN PRETTY CONSISTENT IN SHOVING A DRY SLOT ACROSS THE FORECAST AREA THURSDAY...THE IMPLICATION BEING THAT THE THREAT FOR PRECIP SHOULD WIND DOWN DURING THE MORNING WHICH THE CURRENT FORECAST ACCOUNTS FOR. THIS LOOKS LIKE IT CONTINUES INTO THURSDAY NIGHT/ FRIDAY...SO WILL EXTEND THIS DRY PERIOD ACROSS NORTHERN LOWER INTO THOSE PERIODS AS WELL. DRY SATURDAY FORECAST STILL LOOKS FINE AT THIS POINT AS A SOUTHERN BRANCH SHORT WAVE ZIPS ACROSS THE OHIO VALLEY. JPB && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ341-342- 344>346. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LHZ346>349. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 130 AM EDT TUE MAR 11 2008 UPDATED FOR AVIATION DISCUSSION .UPDATE... DRY AIRMASS EXISTS ACROSS THE NORTHERN PLAINS INTO THE UPPER GREAT LAKES...AS NOTED BY 00Z SOUNDINGS FROM INL...BIS...MPX AND GRB. EVEN INTO SOUTHERN MANITOBA...THE AIRMASS IS DRY...WITH THE PAS SOUNDING SHOWING DEWPOINT DEPRESSIONS OF 5C OR MORE THROUGHOUT THE TROPOSPHERE. THIS DRY AIRMASS IS LOCATED ON THE SOUTH SIDE OF A 1009MB LOW CURRENTLY MOVING FROM LAKE WINNIPEG INTO NW ONTARIO. NORTH OF THE SFC LOW IN THE COLDER AIR...11-3.9U IMAGERY DEPICTS PLENTY OF LOW CLOUDS...WITH SOME FLURRIES BEING REPORTED AT A FEW SITES. WARM FRONT ASSOCIATED WITH THE LOW EXTENDS SOUTH TO NEAR FARGO. DESPITE ISENTROPIC LIFT ACROSS THIS FRONT ON WESTERLY WINDS...ALONG WITH A FAIRLY POTENT SHRTW ON WATER VAPOR DROPPING DOWN INTO CENTRAL MANITOBA...THE DRY AIRMASS HAS RESTRICTED ANY CLOUD DEVELOPMENT TO JUST A FEW MID CLOUDS. HIGH CLOUDS ARE PRESENT...BUT THESE ARE MAINLY ASSOCIATED WITH MOISTURE COMING FROM THE PACIFIC THROUGH THE UPPER LEVEL FLOW AS SEEN ON WATER VAPOR. 21Z/00Z RUC AND 18Z/00Z NAM SEEM TO BE HANDLING THE MOISTURE AVAILABILITY WITH THIS SYSTEM DROPPING TOWARDS THE CWA TONIGHT AND TOMORROW BETTER THAN THE 12Z/18Z GFS...AND BOTH SUGGEST MAINLY A MID/HIGH CLOUD SCENARIO. PERHAPS THERE IS AN OPPORTUNITY TOMORROW MORNING OVER THE EASTERN CWA TO GENERATE SOME PCPN WITH A LONGER TIME FRAME FOR ISENTROPIC LIFT AND DYNAMICAL FORCING. HOWEVER...THE REST OF TONIGHT LOOKS DRY ACROSS ALL OF THE CWA. LOWERED POPS OVER THE WESTERN CWA TOMORROW MORNING...BUT STILL MAINTAINED THEM FOR THE AFTERNOON AS THE AREA OF LOW CLOUDS NORTH OF THE LOW DROPS SOUTH. NO OTHER CHANGES MADE TO THE FORECAST. && .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW INTO THE WESTERN GREAT LAKES BTWN A TROF OVER ERN CANADA AND A RIDGE OVER WRN NOAM. THE MAIN UPSTREAM FEATURE WAS...A SHORTWAVE TROUGH MOVING FROM NORTHERN ALBERTA INTO SASKATCHEWAN. AT THE SFC...WRLY FLOW WAS INCREASING BTWN HIGH PRES OVER IA/KS/MO AND A TROUGH/FRONT OVER NRN ONTARIO. WITH THE VERY DRY AIRMASS IN PLACE...THE WAA PATTERN INTO UPPER MI WAS ONLY BRINGING AN INCREASE IN HIGH CLOUDS. && .SHORT TERM (TONIGHT AND TUESDAY)... ALTHOUGH RADIATIONAL COOLING MAY ALLOW TEMPS TO FALL OFF THIS EVENING...INCREASING WINDS AND HIGH CLOUDS OVERNIGHT MAY RESULT IN STEADY OR SLOWLY RISING TEMPS FROM MIN VALUES IN THE UPPER TEENS. DOWNSLOPE WSW WINDS WILL ALSO KEEP TEMPS UP OVER PORTIONS OF WEST AND N CNTRL UPPER MI. TUE...MODERATE TO STRONG 700-500 MB QVECTOR CONV ALONG WITH FAIRLY STEEP 700-500 MB LAPSE RATES(AROUND 7 TO 7.5 C/KM) SHOULD BE ENOUGH TO SUPPORT SOME LIGHT SNOW FROM NRN LAKE SUPERIOR INTO THE NE CWA IN SPITE OF THE ANTECEDENT DRY AIR. SO...THE FCST LEANED A BIT MORE TOWARD THE GFS AND CANADIAN REGIONAL GEM WITH LIKELY POPS NE AND CHANCE N CNTRL COMPARED TO THE NAM WHICH DOES NOT PRODUCE ANY PCPN OVER UPPER MI. ANY PCPN SHOULD TAPER OFF IN THE AFTERNOON. MODEL SOUNDINGS AND LOW LEVEL WET-BULB ZERO VALUES WOULD KEEP PCPN AS SNOW. QPF VALUES SUGGEST ANY SNOWFALL WILL BE LESS THAN INCH. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... NW WINDS ON BACK SIDE OF LOW ALONG WITH H85 TEMPS NEAR -10C GOOD ENOUGH FOR CHANCE POPS EARLY TUE NIGHT OVR FAR EAST CWA. OTHERWISE...EXPECT CLEARING SKIES WITH TEMPORARY RIDGING. PWAT MIN MOVING THROUGH SUGGESTS SOME RADIATIONAL COOLING CAN TAKE PLACE. WENT BLO GUIDANCE FOR MIN TEMPS. INCREASING CLOUDS BY MIDDAY WED THEN MIXED PRECIPITATION STILL ON TRACK FOR LATE WEDNESDAY INTO WEDNESDAY EVENING. GFS/ECMWF/CANADIAN IN VERY GOOD AGREEMENT IN TRACKING A NORTHERN STREAM WAVE (A PIECE OF ENERGY EMERGING FM THE STRONGER SHORTWAVE NOW OFFSHORE OF BRITISH COLUMBIA) AND SFC LOW JUST NORTH OF LK SUPERIOR ON THU. DESPITE FACT THAT GFS SHOWS H3 JET STREAKING INTO GREAT LAKES ON WED NIGHT AND THE ECMWF NOT HAVING ANY SUCH FEATURE...MAJORITY OF PCPN THAT OCCURS WED NIGHT IS TIED TO LIFTING ALONG ADVANCING SFC TROUGH AND ISENTROPIC LIFT ON THE 280-290K SFCS. GFS/ECMWF SHOW MUCH BETTER AGREEMENT ON THESE FEATURES ALONG WITH RESULTING QPF. HAVE INCREASED POPS TO LIKELY. PTYPE ALSO SEEMING TO COME INTO SOME AGREEMENT. DEPENDING ON HOW QUICKLY PCPN ARRIVES ON WED POTENTIAL FOR RAIN/SNOW MIX EXISTS INTO EARLY WED EVENING DUE TO RESIDUAL WARM AIR NEAR SFC. 1000-850MB THICKNESSES AND 2M TEMPS FM ECMWF/GFS SUGGEST ANY MIXED RAIN/SNOW WOULD CHANGE TO SNOW BY 06Z THU. COULD SEE UP TO 2 INCHES OF SNOW WITH THE SYSTEM ON WED NIGHT. IN WAKE OF THE SFC TROUGH...DRY AIR SHOULD LIMIT PCPN CHANCES THU. ECMWF/GFS/CANADIAN ALL SHOW A MINIMUM IN QPF IN THE 12 HR PERIOD ENDING AT 00Z FRI. PACIFIC AIR PUSHING IN BEHIND THE TROUGH ALLOWS TEMPS TO WARM INTO THE 30S. SO...IF ANY PCPN DOES OCCUR IT WOULD LIKELY BE IN FORM OF A RAIN/SNOW MIX OR STRICTLY RAIN. PREFERRED LESS AMPLIFIED/WARMER ECMWF/CANADIAN COMPARED TO GFS INTO THE WEEKEND. 12Z GFS IS COMING AROUND TO LESS TROUGHING OVR THE WESTERN GREAT LAKES. H9-H85 TEMPS LOOK MARGINAL FOR LK EFFECT BUT WITH A NORTH WIND AND WEAK CYCLONIC FLOW LINGERING NEED TO KEEP SOME POPS NEAR LAKE SUPERIOR FRI INTO SAT. LK EFFECT ENDS BY SUNDAY AS WINDS BECOME SE WITH SFC RIDGE MOVING ACROSS THE AREA. GFS/ECMWF CONSISTENT ON DEVELOPING SIGNIFICANT STORM SYSTEM OVR NATIONS MID SECTION BY NEXT MONDAY. ECMWF HAS LATCHED ONTO THIS SOLUTION AND BEEN FAIRLY CONSISTENT WITH IT FOR THE LAST FEW DAYS. DETAILS SHOULD BE TAKEN WITH GRAIN OF SALT AT THIS POINT AS THE SHORTWAVES THAT ARE PROGGED TO MORPH INTO THIS LARGE SYSTEM ARE STILL OUT IN THE PACIFIC...NEAR THE GULF OF ALASKA AND EXITING JAPAN. WILL NEED TO WAIT TIL THE UPCOMING WEEKEND WHEN ENERGY REACHES THE WEST COAST BEFORE IT BECOMES SAMPLED BY RAOB NETWORK. IT IS PRETTY INTERESTING THOUGH HOW CONSISTENT THE MODELS HAVE BEEN WITH A SYSTEM THIS FAR OUT IN TIME. STRONG NEGATIVELY TILTED SYSTEMS EJECTING OUT OF THE SOUTHWEST CONUS CAN END UP SLOWER THAN PROGGED SO DECIDED TO KEEP PCPN OUT OF CWA ON SUN NIGHT. FOR NOW...HAVE CHANCE POPS OVER ALL AREAS BY LATE ON DAY 7. TRACK OF STORM SUGGESTS SNOW FOR PTYPE BUT A FARTHER WEST TRACK WOULD RESULT IN LIQUID PCPN. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... DRY AIRMASS OVER UPPER MI WILL HELP TO MAINTAIN VFR CONDITIONS AT BOTH TAF SITES THROUGH THE MORNING...DESPITE THE APPROACH OF A LOW PRESSURE SYSTEM FROM SOUTH CENTRAL CANADA. HOWEVER...WIND SHEAR WILL BE AN ISSUE WITH THIS SYSTEM AS A LOW LEVEL JET MOVES ACROSS THE TAF SITES. AS THE SURFACE LOW MOVES TOWARDS EASTERN ONTARIO IN THE AFTERNOON...A COLD FRONT IS EXPECTED TO DROP SOUTH ACROSS UPPER MI. BEHIND THE FRONT UPSTREAM...A MVFR STRATUS DECK WITH A FEW FLURRIES EXIST...WHICH SHOULD MOVE INTO THE TAF SITES EARLY IN THE AFTERNOON. HAVE KEPT OUT THE MENTION OF -SN FOR NOW...BUT WOULD NOT BE SURPRISED TO SEE SOME 7SM -SN OCCUR. A RIDGE OF HIGH PRESSURE WILL BUILD INTO WESTERN UPPER MI IN THE EVENING. DRY AIR ASSOCIATED WITH THE RIDGE SHOULD ALLOW CLOUDS TO BREAK UP INTO A SCATTERED DECK AT CMX. A MORE PERSISTENT CLOUD DECK IS PLANNED AT SAW...DUE TO NORTH TO NORTHEAST WINDS BRINGING LAKE EFFECT CLOUDS OFF THE SOMEWHAT ICE FREE EASTERN LAKE SUPERIOR. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SOUTHWEST WINDS TO 30 KT ARE EXPECTED OVER PORTIONS PORTIONS OF LAKE SUPERIOR TONIGHT AHEAD OF THE NEXT APPROACHING LOW PRES TROUGH FROM CANADA. AS THE TROUGH PASSES ON TUESDAY WINDS WILL SHIFT NORTHWEST TO 25 KT OVER THE ERN HALF OF THE LAKE TUESDAY AFTERNOON AND EVENING. WINDS DIE OFF BRIEFLY LATE TUESDAY NIGHT AND EARLY WEDNESDAY BUT THEN INCREASE AGAIN TO 30 KT FROM THE SOUTH-SOUTHEAST WED EVENING AHEAD OF YET ANOTHER CLIPPER LOW WED NIGHT. WINDS SHIFT WEST-NORTHWEST BY FRIDAY BEHIND THE TROUGH PASSAGE AND MAY APPROACH 30 KT OVER THE FAR ERN PORTION OF THE LAKE. DUE TO EXTENSIVE ICE COVERAGE OVER THE WEST HALF OF THE LAKE AND WARMING TEMPERATURES...FREEZING SPRAY WILL NOT BE MUCH OF A FACTOR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...AJ SHORT TERM...JLB LONG TERM...JLA MARINE...JLB AVIATION...AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 126 AM EDT TUE MAR 11 2008 .AVIATION... STILL WATCHING THE FOR THE DEVELOPMENT OF MAINLY LIGHT FOG OVERNIGHT AND THROUGH SUNRISE AS LOW-LEVEL MOISTURE INCREASES IN ADVANCE OF AN APPROACHING COLD FRONT. VISIBILITIES ARE ALREADY SLIGHTLY RESTRICTED AT DETROIT TERMINALS. PATCHY DENSE FOG HAS DEVELOPED NEARBY...AND MAY AFFECT THESE SITES OVERNIGHT...ESPECIALLY KDET...NEARER LAKE ST CLAIR. SOUTHWEST WINDS WILL BECOME WELL ESTABLISHED BY SUNRISE AS WELL...AND WILL INCREASE THROUGH THE DAY AS THE FRONT APPROACHES FROM THE NORTHWEST. WINDS WILL THEN VEER TO NORTHWEST AS THE FRONT TRAVERSES THE FORECAST AREA BETWEEN 00-06Z WEDNESDAY. && .PREV DISCUSSION...ISSUED 340 PM EDT MON MAR 10 2008 SHORT TERM...THIS AFTERNOON AND TONIGHT THE QUALITY OF MOISTURE HAS REMAINED POOR...KEEPING THE SNOW ACTIVITY TO PREDOMINATELY FLURRIES. LATEST TAMDAR SOUNDINGS DEPICT A SATURATED ENVIRONMENT LIMITED TO THE 900-700MB LAYER. THIS AFTERNOONS WATER VAPOR IMAGERY/RUC GUIDANCE EXITS THE SHORTWAVE RESPONSIBLE FOR THE CLOUDS/FLURRIES MOMENTARILY. WILL CARRY NO HYDROMETEORS THIS EVENING AND OVERNIGHT WITH SUBSIDENCE/ANTICYCLONIC VORTICITY ADVECTION AND LOSS OF ANY DIURNALLY ENHANCED LAPSE RATES. TEMPERATURES SHOULD DIP RATHER QUICKLY THIS EVENING AS WINDS REMAIN SUBDUED AND CLOUDS SCATTER QUICKLY. MAINLY GONE A DEGREE OR TWO BELOW GUIDANCE GIVEN FAVORABLE RADIATING CONDITIONS...AROUND 20 FOR MOST AREAS. SHOULD NOT GET QUITE AS COLD TONIGHT SINCE RETURN FLOW WILL DEVELOP ALLOWING FOR SOME WARM AIR ADVECTION. LONG TERM...TUESDAY THROUGH MONDAY THE 12Z MODEL SUITE ARE IN GOOD AGREEMENT WITH RESPECT TO A NORTHERN STREAM WAVE EXPECTED TO MOVE ACROSS THE STATE FROM CENTRAL CANADA TUESDAY AFTERNOON AND EVENING. THE CURRENT WATER VAPOR LOOP ALREADY INDICATES A STRONG UPPER JET OVER WESTERN CANADA. THIS JET IS FORECAST TO DIVE INTO THE WESTERN GREAT LAKES REGION TUESDAY AFTERNOON...STRENGTHENING TO 110 KTS. UPPER DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF THIS JET WILL BE FOCUSED ACROSS SOUTHERN MICHIGAN BY 00Z WED. THE UPPER JET WILL ALSO ALLOW THE MID LEVEL WAVE TO AMPLIFY AS IT CROSSES THE STATE. THE ASSOCIATED SURFACE LOW IS EXPECTED TO PASS NORTH OF THE STATE...WHILE A SURFACE TROUGH AXIS SWINGS THROUGH SE MI BETWEEN 00Z AND 03Z WED. THIS SYSTEM IS EXPECTED TO HAVE GOOD DYNAMICS...WITH A STRONG YET BRIEF SHOT OF DCVA AND UPPER DIVERGENCE. MODEL SOUNDINGS SHOW LACK OF DEEP MOISTURE TO BE THE MAIN LIMITING FACTOR FOR PRECIP. ALL MODEL SOLUTIONS DO HOWEVER SHOW A NARROW RIBBON HIGHER 850-700MB THETA E AIR ADVECTING AHEAD OF THE SURFACE TROUGH. THIS COMBINED WITH THE DYNAMICS WILL WARRANT A LOW CHANCE OF PRECIP BETWEEN THE 21Z TUE AND 03Z WED TIME FRAME. WITH SURFACE TEMPS FORECAST TO RISE INTO THE UPPER 30S/NEAR 40 TUES AFTERNOON...THE BOUNDARY LAYER LOOKS TO BE WARM ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW. MID LEVEL HEIGHTS WILL QUICKLY REBOUND ACROSS THE STATE ON WEDNESDAY IN THE WAKE OF TUESDAY EVENINGS WAVE. SKIES SHOULD ALSO CLEAR OUT BY WEDNESDAY MORNING AS SURFACE HIGH PRESSURE BUILDS ACROSS THE REGION. A BACK DOOR COLD FRONT...ASSOCIATED WITH THE DEPARTING LOW IS FORECAST TO SINK S-SE ACROSS LAKE HURON LATE TUES NIGHT INTO WEDNESDAY...CAUSING 850MB TEMPS TO DROP TO -8 TO -10C OVER THE THUMB REGION BY WED MORNING. THUS...HAVE BACKED OFF WED HIGHS A BIT...CARRYING MAX TEMPS ONLY IN THE LOWER 30S IN THE THUMB TO NEAR 40 WEST OF THE I-75 CORRIDOR. BY WEDNESDAY EVENING THE NEXT WAVE IS ALREADY FORECAST TO BE ADVANCING INTO THE WESTERN GREAT LAKES REGION IN THE VERY PROGRESSIVE NORTHERN STREAM. WHILE THE MAIN SURFACE LOW IS FORECAST TO PASS NORTH OF THE STATE...MODELS DO SHOW AN OCCLUDED FRONT MOVING ACROSS SOUTHERN MI EARLY THURS MORNING. STRONG LOW TO MID LEVEL THETA E ADVECTION LATE WED NIGHT AND THURSDAY MORNING WILL AGAIN WARRANT A CHANCE OF PRECIP. MODELS ARE NOT OVERLY ROBUST WITH THE QPF. HOWEVER GIVEN THE MAGNITUDE OF ISENTROPIC ASCENT...WILL CONTINUE WITH HIGH CHANCE POPS OVERNIGHT WED THROUGH THURS MORNING. A WARMING BOUNDARY LAYER SHOULD SUPPORT MAINLY RAIN AROUND THE DETROIT AREA. LOWER WET BULB ZERO HEIGHTS FARTHER NORTH SHOULD HOWEVER SUPPORT A RAIN/SNOW MIX...POSSIBLY EVEN SOME SLEET. WITH THE FLOW ALOFT TRANSITIONING TO MORE ZONAL ACROSS THE CONUS BY LATE IN THE WEEK...THE AMOUNT OF COLD AIR ADVECTION IS NOT OVERLY IMPRESSIVE IN THE WAKE OF THURSDAYS SYSTEM. THE CURRENT FORECAST HAS HIGHS IN THE LOW TO MID 40S THURS AND FRI WHICH STILL LOOKS REASONABLE. THE NEXT SYSTEM TO MONITOR IS A WAVE IN THE SOUTHERN STREAM FORECAST TO MOVE ACROSS THE OHIO VALLEY ON SATURDAY. THE GFS HAS BEEN TRENDING MORE AMPLIFIED WITH THIS WAVE...AS WELL AS WITH MID LEVEL FGEN OVER THE SOUTHERN GREAT LAKES. THIS MORE AMPLIFIED SOLUTION SOLUTION WOULD BRING COLDER AIR INTO THE STATE ON SATURDAY ALONG WITH THE POTENTIAL FOR ACCUMULATING SNOWFALL ACROSS THE METRO DETROIT AREA AND POINTS SOUTH. THE 12Z ECMWF ALONG WITH SEVERAL GFS ENSEMBLE MEMBERS KEEP THE BULK OF QPF SOUTH OF THE STATE. SO AT THIS TIME A CHANCE OF SNOW ACROSS THE SOUTHERN 1/3RD OF THE CWA SEEMS REASONABLE. MARINE... SURFACE LOW PRESSURE IS FORECAST TO PASS JUST NORTH OF LAKE HURON LATE TUESDAY AFTERNOON AND EVENING...SENDING A COLD FRONT ACROSS THE LAKE AROUND 00Z. SOUTHWESTERLY WINDS WILL INCREASE ACROSS THE LAKES TUES AFTERNOON. MODEL SOUNDINGS ONLY SHOW LIMITED MIXING HEIGHTS OVER LAKE HURON. THE SHALLOW INSTABILITY HOWEVER SHOULD BE ENOUGH TO PROVIDE FREQUENT GUSTS OF 25 TO 30 KNOTS TUES AFTERNOON. MIXING HEIGHTS WILL INCREASE OVER THE LAKES WED NIGHT IN THE WAKE OF THE SURFACE FRONT. THE GRADIENT WILL HOWEVER BEGIN TO WEAKEN...THUS WIND GUSTS SHOULD REMAIN AROUND 25 KNOTS ACROSS THE OPEN WATERS OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION BY WED AFTERNOON...ALLOWING THE WINDS TO BECOME LIGHT AND VARIABLE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... BRISK WIND ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM TUESDAY TO 8 PM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DG SHORT TERM...CB LONG TERM....SC MARINE.......SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 354 AM CDT TUE MAR 11 2008 .DISCUSSION... CLEAR SKIES AND LIGHT WINDS AS THE SURFACE HIGH SETTLED IN HAS RESULTED IN VISIBILITIES STARTING TO LOWER ACROSS PART OF THE AREA. WILL KEEP THE MENTION OF FOG IN THROUGH THE MORNING HOURS. IN THE UPPER LEVELS...ANOTHER COMPACT...BUT RATHER INTENSE CIRCULATION IS CUTTING SOUTHEAST THROUGH NM. THIS LOW WILL MOVE ACROSS THE REGION TODAY. RUC ANALYSIS SHOWS 500MB TEMPS DOWN TO -20C OR COLDER. THIS MAY BE ENOUGH TO SET OFF A FEW ISOLATED SHOWERS AND/OR THUNDERSTORMS IN THE CONCHO VALLEY AND NORTHERN EDWARDS PLATEAU AS LAPSE RATES INCREASE TO 7.5 TO 8 C/KM. TEMPERATURES WILL INCREASE ACROSS THE AREA TODAY WITH SOUTHERLY FLOW...INCREASING THERMAL RIDGING. THE WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK...AS SOUTHERLY FLOW CONTINUES. AS TEMPERATURES INCREASE...RELATIVE HUMIDITY VALUES WILL DECREASE... AND WILL RESULT IN ELEVATED FIRE DANGER WHICH WILL BE DISCUSSED IN FURTHER DETAIL BELOW. TEMPERATURES WILL WARM INTO THE 80S BY THURSDAY AND FRIDAY. ON FRIDAY...SURFACE WINDS MAY INCREASE SIGNIFICANTLY. AN UPPER LEVEL TROUGH IS FORECAST TO MOVE WEST TO EAST ACROSS THE REGION. AS THIS TAKES PLACE...A SURFACE LOW IS FORECAST TO DEEPEN AND TRANSLATE TO THE EAST OVER OK. THIS WILL INCREASE WESTERLY WINDS...AND WITH 700MB WINDS AT 40 OR 50 KNOTS COMBINED WITH GOOD MIXING...WE MAY SEE WINDS OF 25 TO 35 MPH WITH GUSTS AS HIGH AS 40 MPH. THIS WILL ALSO DRIVE THE DRYLINE EAST THROUGH THE AREA...AND WITH DOWNSLOPING WINDS... DRIER AIR...WE MAY SEE TEMPERATURES REACHING INTO THE UPPER 80S OR EVEN LOWER 90S IN SOME LOCATIONS. CHANCES FOR PRECIP ASSOCIATED WITH THIS FRONT ARE NOT HIGH ENOUGH FOR POPS TO BE INSERTED. A COLD FRONT WILL FOLLOW THIS SYSTEM SATURDAY...BRINGING TEMPERATURES CLOSER TO NORMAL FOR THE WEEKEND. ANOTHER UPPER LEVEL LOW IS EXPECTED TO IMPACT THE AREA DURING THE EARLY PART OF NEXT WEEK...GIVING THE AREA A CHANCE FOR SHOWERS AND THUNDERSTORMS...DEPENDING ON THE AMOUNT OF MOISTURE RETURN AND PATH OF THE UPPER LEVEL SYSTEM. HAVE KEPT THE SLIGHT CHANCE OF PRECIP IN FOR NOW...MAINLY OVER THE EASTERN 2/3 OF THE CWA. .FIRE WEATHER... TEMPERATURES WILL WARM DURING THE SECOND HALF OF THE WORK WEEK ACROSS THE AREA AS A THERMAL RIDGE INCREASES OVER THE AREA. FIRE WEATHER DANGERS WILL RISE AS MINIMUM RELATIVE HUMIDITY VALUES FALL. CURRENTLY...THE DAY WITH THE HIGHEST POTENTIAL FOR REACHING CRITICAL FIRE WEATHER VALUES IS FRIDAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA DEEPENING A SURFACE LOW TO THE NORTH OF OUR AREA...AND BRING STRONG MID LEVEL WINDS WITH IT AS WELL. THIS PATTERN IS FAVORABLE FOR PUSHING THE AREA INTO EXTREMELY CRITICAL VALUES CONCERNING FIRE WEATHER. MIXING WILL BE STRONG...AND MAY RESULT IN WIND GUSTS TO 40 MPH OR GREATER OUT OF THE WEST FOR MUCH OF THE AREA. THESE STRONG WEST WINDS WILL ALSO PUSH A DRYLINE THROUGH THE AREA WHICH WILL CAUSE TEMPERATURES TO RISE INTO THE UPPER 80S TO NEAR 90. THIS WILL ALLOW RELATIVE HUMIDITY VALUES TO FALL TO LESS THAN 10 PERCENT ACROSS WESTERN PARTS OF THE CWA. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 67 49 77 53 / 10 0 0 10 SAN ANGELO 67 46 76 53 / 10 0 0 10 JUNCTION 69 46 75 54 / 10 0 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 20 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1227 AM CDT TUE MAR 11 2008 .AVIATION... CLEAR SKIES...DEW POINTS IN THE 40S AND LIGHT WINDS WILL ALLOW FOR SOME AREAS OF BR TO FORM DURING THE OVERNIGHT...AS OF NOW THE THINKING IS THE MOST LIKELY AREAS FOR BR TO DEVELOP WILL BE ACROSS THE HEARTLAND...NORTHWEST HILL COUNTRY AND NORTHERN EDWARD PLATEAU..HAVE INCLUDED BR AS FAR NORTH AS KSJT TERMINAL BUT THE LOWER VISIBILITIES WILL BE FARTHER SOUTH...SO HAVE MVFR TO IFR VISIBILITIES AS OF NOW IN THE TAFS...BUT WILL NEED TO MONITOR FOR LIFR VISIBILITIES TO DEVELOP. SOUTHERLY WINDS AT 10 TO 15 KNOTS WILL PICK UP LATE MORNING AND CONTINUE THROUGH THE AFTERNOON AND EVENING. && .PREV DISCUSSION... /ISSUED 651 PM CDT MON MAR 10 2008/ UPDATE... MAIN UPDATE TO GOING FCST WAS TO INSERT AREAS OF FOG OVER THE CONCHO VALLEY, HEARTLAND, AND NORTHWEST HILL COUNTRY LATE TONIGHT AND EARLY TUESDAY. SURFACE WINDS ARE VEERING TO THE EAST LATE THIS AFTERNOON AND WILL BECOME LIGHT SOUTHEASTERLY TONIGHT. THIS WILL GRADUALLY BRING BACK THE BETTER LOW LEVEL MOISTURE OVER SOUTHERN AND EASTERN TEXAS. THIS...COMBINED WITH RADIATIONAL COOLING FROM THE MOSTLY CLEAR SKIES EXPECTED TONIGHT WILL RESULT IN FOG AND/OR LOW STRATUS DEVELOPMENT...MAINLY OVER THE SOUTHERN AND EASTERN PORTIONS OF THE FCST AREA. RUC MODEL SOUNDINGS AT KSJT AND KJCT AT 09Z TUE SUGGEST FAVORABLE HYDROLAPSES WITHIN THE LOWEST 10 TO 20 MB OF THE SOUNDING TO SUPPORT DENSE FOG IN SOME SPOTS. WILL HAVE TO MONITOR LATER TONIGHT TO SEE IF AN ADVISORY WILL BE NEEDED. LACY PREV DISCUSSION... /ISSUED 631 PM CDT MON MAR 10 2008/ AVIATION... MAIN ISSUES THIS TAF PACKAGE WILL BE POSSIBLE LOW CLOUDS AND SOMEWHAT LOWER VISIBILITIES LATE TONIGHT INTO EARLY MORNING ACROSS SRN HALF OF AREA...IE SOA/SJT/JCT/BBD TAFS. WITH LIGHTER WINDS AND SOME RETURN FLOW COULD SEE SOME INSTANCES. MUCH MORE WIND EXPECTED BY MID TO LATTER PORTION OF THE WEEK WITH BETTER SRLY FLOW. 11/KEISER PREV DISCUSSION... /ISSUED 316 PM CDT MON MAR 10 2008/ SHORT TERM... UPPER LEVEL TROUGH OVER WC TEXAS MOVING EAST THIS AFTERNOON... WITH CLEARING SKIES. ANY CUMULUS THIS AFTERNOON SHOULD QUICKLY DISSIPATE IN THE EARLY EVENING. WINDS WILL ALSO DECOUPLE THIS EVENING...BECOMING LIGHT AS SURFACE HIGH PRESSURE CENTERS OVER WEST CENTRAL TEXAS EARLY TUESDAY MORNING. WENT A FEW DEGREES BELOW GUIDANCE WITH GOOD RADIATIONAL COOLING TONIGHT. LONG TERM... UPPER LOW SEEN IN THE WATER VAPOR LOOP OVER COLORADO WILL MOVE ACROSS WC TEXAS TUESDAY. MAIN EFFECT WILL BE SCATTERED MID/HIGH CLOUDS. MAY SEE SOME VIRGA...BUT DRY LOWER ATMOSPHERE EVAPORATE ANY MID LEVEL SHOWERS. DRY THIS WEEK...WITH ELEVATED FIRE DANGER WEDNESDAY THROUGH FRIDAY. SURFACE LOW DEVELOPS IN THE PANHANDLE WEDNESDAY...WITH DRY PACIFIC FRONT THURSDAY. FRIDAY HAS THE MOST POTENTIAL FOR WILDFIRE DANGER...AS A SURFACE LOW MOVES FROM THE PANHANDLE MOVE SOUTHEAST ALONG THE RED RIVER DURING THE DAY FRIDAY. TOO EARLY TO TELL HOW MUCH WIND. GFS MODEL CENTERS THE SURFACE LOW NEAR HASKELL...WHICH WOULD KEEP WINDS LIGHT ACROSS MUCH OF THE BIG COUNTRY (BUT STRONG IN THE CONCHO VALLEY). IF FARTHER NORTH LIKE ON THE ECMWF MODEL...TOWARD THE RED RIVER/SOUTHERN OKLAHOMA...DRY WEST WINDS MIGHT BE SIGNIFICANTLY STRONGER IN THE 25-35 MPH RANGE ACROSS THE BIG COUNTRY. TEMPERATURES IN THE LOWER 80S WOULD JUST ENHANCE THE FIRE DANGER. WENT MORE TOWARD THE STRONGER WINDS IN THIS ZONE PACKAGE. OTHERWISE LONG WAVE UPPER TROUGH APPROACHES TEXAS EARLY NEXT WEEK. ECMWF SIMILAR TO GFS...BUT JUST A HINT FASTER. BASICALLY JUST LEFT A SLIGHT CHANCE OF THUNDERSTORMS SUNDAY INTO MONDAY...WHICH WAS ALREADY IN THE FORECAST. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 68 49 76 55 / 10 0 0 10 SAN ANGELO 67 43 75 54 / 0 0 0 10 JUNCTION 71 43 74 53 / 10 0 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/28 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 648 AM EDT TUE MAR 11 2008 .AVIATION... MVFR CONDITIONS ACROSS A LARGE PORTION OF THE FORECAST AREA WILL IMPROVE AS WINDS INCREASE AND MIX THE LOWER LEVELS THIS MORNING. VSBYS CURRENTLY NEAR 3-5SM WILL RISE ABV 6SM BY 14-15Z AT THE LATEST AS WINDS INCREASE FROM THE SOUTHWEST AS A SFC HIGH MOVES SOUTH OF THE REGION. WINDS WILL INCREASE WITH GUSTS AROUND 15-20KTS THIS AFTERNOON INTO THE EARLY EVENING WITH MAINLY CLEAR SKIES. HIGH CIGS ABV 15K FT WILL BE POSSIBLE LATE IN THE PERIOD WITH THE WINDS VEERING SLIGHTLY TO THE WEST OR WNW AND LESSENING BELOW 10KTS AS THE GRADIENT BEGINS TO WEAKEN OVERNIGHT. && .SHORT TERM (TODAY AND TONIGHT)... SFC HIGH IN CONTROL OF THE REGION THIS MORNING...CENTERED JUST EAST OF STL AS OF THIS WRITING. NORTHWEST FLOW ALOFT WITH TROUGH AXIS NEAR OR ACROSS THE EASTERN COASTLINE. SKIES BEGAN TO CLEAR OVERNIGHT ALLOWING FOR DECENT RAD COOLING FOR MOST OF THE REGION...AND IN COMBO WITH LIGHT WINDS AND AMPLE LOW LEVEL MOISTURE HAVE CREATED STRONG CONDITIONS FOR FOG DEVELOPMENT EARLY THIS MORNING. WILL CONTINUE TO MONITOR FOR ANY SIGNIFICANT DROPS IN VSBY...ESPECIALLY ACROSS THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA. THE LATEST RUC 13 RUN WOULD SUGGEST THAT VSBYS WOULD NEAR DENSE FOG CRITERIA BY 10Z...WILL WATCH THE CLEARING OF THE CLOUDS...TIMING...AND VSBY DROPS AFTERWARD TO SEE IF A DENSE FOG ADVISORY WILL BE NEEDED LATER THIS MORNING. GFS APPEARS TO HAVE WAY TOO MUCH MOISTURE WITH THE FAST MOVING CLIPPER-LIKE SYSTEM THAT DRIVES THROUGH THE GREAT LAKES THIS EVENING AND OVERNIGHT. THE DRIER NAM MOISTURE FIELDS SEEM A BETTER FIT AS THE SYSTEM HAS NO WAY TO TAP THE GULF. EXPECT NEAR FULL SUN FOR THIS MORNING INTO THE EARLY AFTN...MOST IF NOT ALL OF THE REMAINING SNOWPACK SHOULD BE RELEASED IN THE NEXT 24HRS. THE SNOWPACK HAD LITTLE AFFECT ON TEMPS TODAY WITH HIGHS IN THE LOWER 40S WHERE SNOW LIES...WITH THE INCREASING SUN ANGLE HAVE NOT ACCOUNTED FOR THE OLDER SNOWFIELD COOLING AS MUCH AS NORMALLY WOULD. MOS EQUATIONS MAY STILL BE USING WINTER SCHEME...AND WOULD NOT ACCOUNT FOR THE STRONGER MID MARCH SUN ANGLE AS WELL...ANOTHER REASON TO GO ABV MOS IN THE SOUTHEAST...THE SOUTHWEST WINDS WILL HELP IN THIS MATTER AS WELL WITH MID 40S OR HIGHER ACROSS MUCH OF THE FORECAST AREA. MID AND UPPER LEVEL CLOUDS ASSOCIATED WITH THE SYSTEM MOVING TO THE NORTH AND EAST OF THE REGION IN THE EVENING. WEAK SFC TROUGH PUSHING THROUGH AFTER MIDNIGHT...WITH JUST A WIND SHIFT TO THE NORTH. EVEN WITH THE NORTH WINDS IN THE EARLY MORN...LOWS WILL BE NEAR NORMAL IN THE UPPER 20S. && .LONG TERM (WEDNESDAY THROUGH MONDAY)... TEMPERATURES WILL CONTINUE TO MODERATE INTO THURSDAY AS SOUTH TO SOUTHWEST WINDS INCREASE AHEAD OF AN APPROACHING SURFACE LOW AND FRONT. HIGHS SHOULD BE ABLE TO REACH NEAR 50F WITH LOW LEVEL FLOW 40 TO 50 KNOTS. KEPT A CHANCE FOR RAIN LATE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THE FRONT SHOULD REACH THE AREA EARLY THURSDAY...AND THEN A WAVE SHOULD DEVELOP ALONG THE FRONT OVER MISSOURI AND MOVE EAST THURSDAY NIGHT. OVERALL THE GFS HAS BACKED OFF BRINGING MUCH COLDER AIR BEHIND THE FRONT THURSDAY NIGHT IN LIEU OF THE WAVE ALONG THE FRONT. THEREFORE...ADDED A MIX OF RAIN AND SNOW LATE THURSDAY NIGHT. THERMODYNAMIC PROFILES CLOSE TO A RAIN AND SNOW MIX. PLACED HIGHER RAIN/SNOW CHANCES OVER SOUTHEAST AREAS WHERE BEST FRONTAL LIFT WILL OCCUR...SO BEST CHANCE FOR RAIN BASICALLY MARION TO LIMA. A SECOND LOW SHOULD MOVE EAST NORTHEAST ALONG THE FRONT SATURDAY. THE BIG CHALLENGE HERE IS HOW FAR NORTH THE PRECIPITATION WILL SPREAD. RAISED SNOW CHANCES TO 50 PERCENT IN THE SOUTH...WITH 25 TO 30 PERCENT IN THE NORTH. A LARGE ANTICYCLONE OVER SOUTH CENTRAL CANADA SHOULD HELP WITH DRY AIR ENTRAINMENT AS A COLD AND DRY NORTHEAST FETCH SETS UP OVER THE GREAT LAKES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...SCHOTT LONG TERM...SKIPPER AVIATION...SCHOTT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1042 AM EDT TUE MAR 11 2008 .UPDATE...1004MB SURFACE LOW NORTH OF SUPERIOR THIS MORNING. MID LEVEL RETURNS INCREASING ACROSS UPPER MI. SUSPECT SOME OF THAT IS REACHING THE GROUND...THOUGH SURFACE OBS NOT YET INDICATIVE OF THAT. IR SATELLITE IMAGERY SHOWS A WELL-DEFINED SHORTWAVE MOVING EAST FROM THE KEWEENAW...A SECOND WAVE IS IMPLIED IN AN AREA OF MID CLOUDS ALONG MN/ONTARIO BORDER. PRECIP TRENDS ARE THE MAIN CONCERN FOR TODAY. THE 2ND WAVE WILL ACTUALLY WILL THE DOMINANT ONE DYNAMICALLY... DIGGING TOWARD CENTRAL LOWER MI. BUT MOISTURE AVAILABILITY IS LESS FARTHER SOUTH...WITH MORE SUSTAINED AND STRONGER ISENTROPIC ASCENT TO THE NORTH. IN ADDITION...MODELS SHOW A BETTER COMBINATION OF STEEP MID-LAPSE RATES ABOVE 650MB...AND LOW LEVEL MOISTURE...ACROSS THE NORTH. THIS IS CERTAINLY INDICATIVE IN PRECIP TENDING TO BE SHOWERY. WILL PLAY UP NUMEROUS SNOW SHOWERS IN EASTERN UPPER MI AND FAR NORTHERN LOWER MI THIS AFTERNOON...WITH SCT POPS TO THE SOUTH...AS MID LEVEL INSTABILITY WILL ONLY OVERCOME LOW LEVEL DRY AIR IN SPOTS. ACCUMS AROUND AN INCH IN EASTERN UPPER MI...LESS THAN THAT SOUTH. MAX TEMPS LOOK OK...MAY NEED TO KICK UP A DEGREE OR TWO IN SPOTS. ZOLTOWSKI && .PREV DISCUSSION...ISSUED 342 AM TUE MAR 11... LARGE SCALE PATTERN LOOKING PROGRESSIVE THIS WEEK WITH A BROAD 4-5 WAVE HEMISPHERIC PATTERN. REMNANTS OF A COUPLE PACIFIC ORIGIN SHORT WAVE TROUGHS WILL SWING THROUGH THE WESTERN GREAT LAKES OVER THE NEXT SEVERAL DAYS...ONE TODAY COMING OUT OF MANITOBA THIS MORNING...AND A SECOND WAVE COMING ONSHORE THIS MORNING LOOKS TO IMPACT THE AREA IN THE THURSDAY TIME FRAME. BEYOND THAT PATTERN BECOMES BASICALLY SPLIT/ZONAL FOR THE WEEKEND...SOME HINTS AT A -NAO TYPE PATTERN DEVELOPING WITH RISING HEIGHTS ACROSS ICELAND/GREENLAND...BUT PROBABLY IN NAME ONLY AS THE TYPICAL RESPONSE OVER NORTH AMERICA (E.G., COLD FOR US) DOES NOT APPEAR TO BE IN THE CARDS WITH POLAR VORTEX BOTTLED UP ABOVE 60N...AND A POSSIBLE RE-APPEARANCE OF THE SOUTHEAST U.S. RIDGE AS HEIGHTS FALL ACROSS THE SOUTHWESTERN STATES. A PROBABLE SET UP FOR MORE COMPLICATED FORECAST ISSUES NEXT WEEK. IN THE MEANTIME...HIGH PRESSURE SINKING SOUTH OF THE STATE THIS MORNING...WITH HEIGHT FALLS ASSOCIATED WITH MANITOBA SHORT WAVE/JET STREAK DIVING TOWARD THE WESTERN LAKES. SURFACE PRESSURES FALLING IN RESPONSE TO THIS (3-4MB/3H PRESSURE FALLS ACROSS WESTERN ONTARIO/NORTHERN MN)....ALLOWING ASSOCIATED SURFACE LOW OVER EASTERN MANITOBA TO DROP SOUTHEAST TOWARD LAKE SUPERIOR. SURFACE LOW FORECAST TO SLIDE ACROSS LAKE SUPERIOR TODAY...WHILE MAIN SHORT WAVE ENERGY COMES RIGHT ACROSS THE LOWER PENINSULA. SO FIRST FORECAST PROBLEM THIS MORNING WILL DEAL WITH PRECIPITATION POTENTIAL WITH THIS SYSTEM. DEEP LAYER RIDGING BUILDS INTO THE WESTERN LAKES FOR WEDNESDAY...THEN NEXT SERIES OF HEIGHT FALLS ARRIVES WEDNESDAY NIGHT/THURSDAY...WHICH IS FORECAST PROBLEM NUMBER TWO. TODAY/TONIGHT...HIGH CLOUDS INVADING NORTHERN MI EARLY THIS MORNING FROM THE NORTHWEST AHEAD OF APPROACHING SHORT WAVE TROUGH. CLOUD TOPS HAVE BEEN COOLING/EXPANDING ACROSS MN AND WESTERN ONTARIO...AND STARTING TO GET INCREASING MOISTURE IN 900-500MB LAYER PER GOES SOUNDER WATER VAPOR IMAGERY. BUT MUCH OF THAT MOISTURE LIKELY ABOVE 700MB WITH JUST A HANDFUL OF OBSERVATIONS OF CLOUDS BELOW 12K FEET THROUGH 06Z (MOSTLY ACROSS ONTARIO). A FEW HIGH BASED RADAR RETURNS HEADED INTO LAKE SUPERIOR PER ONTARIO RADAR COMPOSITE...BUT NO PRECIPITATION AT THE ONSET OF THE FORECAST PERIOD. FORECAST PROBLEM OF THE DAY IS TIMING OF INCREASED SATURATION AS STRONGER DYNAMICS COME INTO PLAY (GOOD QG FORCING AND LFQ JET DYNAMICS). LIFT IS NOT THE PROBLEM...THE QUESTION WILL IT BE ENOUGH TO MOISTEN WHAT IS ADMITTEDLY A RELATIVELY DRY ANTECEDENT AIR MASS. GUIDANCE IS STILL SPLIT ON THIS ISSUE...WITH THE NAM REMAINING DRY (SHUNTING BEST DEEP LAYER MOISTURE QUICKLY EAST OF THE FORECAST AREA THIS MORNING)...AND THE GFS SHOWING BETTER MOISTENING WITH TIME AS STRONGER FORCING ARRIVES. ECMWF/UKMET/RUC THROWING SUPPORT TOWARD THE GFS...AND AS WATER VAPOR IMAGERY SHOWS UPSTREAM WAVE TAKING ON A BETTER ORGANIZED (LESS SHEARED) APPEARANCE...GETTING COLDER CLOUD TOPS NOW DEVELOPING IN THE VICINITY OF LAKE WINNIPEG. GIVEN THE STRENGTH OF THE FORCING HAVE TO BELIEVE THAT DEEP LAYER RH WILL IMPROVE THROUGH THE DAY TO SUPPORT A THREAT OF PRECIPITATION ACROSS THE ENTIRE FORECAST AREA... THOUGH SEE NO NEED TO CHANGE OUR POP DISTRIBUTION WHICH HAS BEEN CONSISTENTLY HIGHER TO THE NORTH. NOT EXPECTING PRECIP CHANCES ACROSS NORTHERN LOWER UNTIL THE AFTERNOON. LAPSE RATES EXPECTED TO BE FAIRLY STEEP ABOVE 750MB...SUPPORTING THE POSSIBILITY OF SOME ELEVATED CONVECTIVE/SHOWERY ELEMENTS DEVELOPING. PRECIP TYPE WILL DEPEND ON DEPTH OF SURFACE BASED WARM LAYER...NAM TRYING TO SHOVE A PRETTY DECENT THERMAL RIDGE INTO THE FORECAST AREA LATER TODAY (925MB TEMPERATURES 4-6C WARMER THAN GFS)...THIS LOOKS OVERDONE BASED ON INITIALIZATION AND 05Z AIRCRAFT SOUNDING OUT OF MPX WHICH INDICATED A 925MB TEMP OF +2C WHEN THE NAM HAD +5C PROGGED AT 06Z. SURFACE TEMPERATURES SHOULD WARM IN TO THE MID 30S AT LEAST...CURRENT FORECAST IS ALL SNOW EVERYWHERE AND THINK THAT`S THE WAY TO GO AT THIS TIME. WILL CONTINUE WITH THE IDEA OF SNOW SHOWERS TAPERING OFF FROM WEST TO EAST DURING THE EVENING HOURS. WEDNESDAY...RIDGING AT THE SURFACE AND ALOFT BUILD IN WEDNESDAY IN THE WAKE OF TODAY`S SYSTEM. SHOULD BE A NICE DAY WITH TEMPERATURES NEAR OR A BIT COOLER THAN TODAY (THE LATTER BEING ESPECIALLY TRUE THE FARTHER NORTH YOU GO). NEXT SYSTEM TO IMPACT THE REGION ARRIVES WEDNESDAY NIGHT AS A SHORT WAVE TROUGH CROSSES THE NORTHERN PLAINS AND INTO THE WESTERN GREAT LAKES THURSDAY MORNING. THIS WILL INCREASE THE THREAT FOR SNOW FROM WEST TO EAST. SOME QUESTION ABOUT PRECIP TYPE BUT THIS FAR OUT WILL KEEP IT SIMPLE (AND ALL SNOW). MARINE ISSUES...WILL CARRY SMALL CRAFT ADVISORIES TODAY THROUGH THIS EVENING ON THE LAKE MICHIGAN SIDE...AND THIS AFTERNOON AND EVENING ON LAKE HURON. NO HEADLINES ANTICIPATED BEYOND TONIGHT. EARLY EXTENDED PERIODS (THURSDAY THROUGH SATURDAY)...GUIDANCE HAS BEEN PRETTY CONSISTENT IN SHOVING A DRY SLOT ACROSS THE FORECAST AREA THURSDAY...THE IMPLICATION BEING THAT THE THREAT FOR PRECIP SHOULD WIND DOWN DURING THE MORNING WHICH THE CURRENT FORECAST ACCOUNTS FOR. THIS LOOKS LIKE IT CONTINUES INTO THURSDAY NIGHT/ FRIDAY...SO WILL EXTEND THIS DRY PERIOD ACROSS NORTHERN LOWER INTO THOSE PERIODS AS WELL. DRY SATURDAY FORECAST STILL LOOKS FINE AT THIS POINT AS A SOUTHERN BRANCH SHORT WAVE ZIPS ACROSS THE OHIO VALLEY. JPB && .AVIATION...ISSUED 132 AM TUE MAR 11... SURFACE HIGH WILL MOVE TO THE EAST OVERNIGHT WITH RETURN FLOW DEVELOPING ACROSS NORTHERN MICHIGAN. THIS MAY HELP TO PRODUCE A FEW LOWER CLOUDS ALONG THE LAKE MICHIGAN SHORELINE...BUT OTHERWISE JUST HIGH/MID CLOUDS. NEXT SHORTWAVE TROF OVER SOUTHERN CANADA WILL SWING DOWN INTO THE GREAT LAKES ON TUESDAY. THIS FEATURE WILL TIGHTEN THE GRADIENT /RESULTING IN GUSTY SOUTHWEST WINDS OF 20KTS/ AND INCREASING CLOUDINESS. MID CLOUDS AND VFR CIGS TUESDAY MORNING WILL GIVE WAY TO AREAS OF MVFR CONDITIONS AFT 18Z AS LOWER CLOUDS DEVELOP /ESPECIALLY AT PLN AND APN/. THERE MAY ALSO BE SOME LIGHT PRECIPITATION DURING THE AFTERNOON AT PLN/APN...PROBABLY IN THE FORM OF LIGHT SNOW. VFR CIGS WILL RETURN TO ALL TAF SITES AFTER 01Z AS SURFACE TROF EXITS THE REGION. JK && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ341-342- 344>346. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LHZ346>349. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1015 AM CDT TUE MAR 11 2008 .DISCUSSION...WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS THE SHORTWAVE OVER THE MS/AL STATE LINE. THIS IS HELPING END THE RAIN A LITTLE FASTER THAN EXPECTED. LOCAL RADARS SHOW MOST OF THE SIGNIFICANT RAIN ENDING JUST EAST OF INTERSTATE 59. AS THE SHORTWAVE AND SFC LOW NEAR THE GULF COAST OF MS SHIFT FARTHER EAST THE RAIN WILL END AND THE CLOUDS WILL BEGIN TO BREAK UP. HIGH PRESSURE OVER THE SOUTHERN PLAINS WILL SHIFT SLOWLY SE TOWARD OUR AREA. TEMPERATURES LOOK ON TRACK NOW BUT IF THE CLOUDS CLEAR A LITTLE FASTER THAN EXPECTED THIS AFTERNOON TEMPERATURES MAY TOP OUT A FEW DEGREES ABOVE CURRENT FORECAST. UPDATED FORECAST FOR POPS HAS BEEN POSTED. && .AVIATION...RAIN IS ENDING FASTER THAN EXPECTED AND CEILINGS HAVE RISEN TO VFR CONDITIONS AT MOST SITES. THE EXCEPTION IS IN THE SOUTH WHERE CEILINGS AT 1000-1500FT ARE RESULTING IN MVFR CONDITIONS. CLOUDS IN THE SOUTH SHOULD RISE DURING THE AFTERNOON. ELSE...SKIES WILL BEGIN TO CLEAR FROM WEST TO EAST DURING THE EVENING HOURS... LEAVING MOST OF THE CWFA CLEAR DURING THE OVERNIGHT HOURS. A FEW SITES MAY SEE A BIT OF MVFR PATCHY FOG OVERNIGHT...BUT THIS SHOULD NOT POSE ANY MAJOR PROBLEMS WITH VSBYS PERIODICALLY DROPPING TO BETWEEN 3-5SM. THIS WILL MAINLY BE BETWEEN 09-13Z. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1145 AM EDT TUE MAR 11 2008 .SYNOPSIS... SEVERAL WEAK WEATHER SYSTEMS WILL MOVE ACROSS THE REGION THROUGH THE NEXT WEEK. THE BEST CHANCE OF RAIN WILL OCCUR SATURDAY...ALTHOUGH A SIGNIFICANT RAIN EVENT IS NOT EXPECTED. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 10 AM TUESDAY...WEAK SFC BOUNDARY HAS MOVED OFF SHORE WITH BRIEF SHIFT OF WINDS TO THE W-NW THIS MORNING. MID TO HIGH LEVEL CLOUDS HAVE BEGUN TO STREAM INTO LOCAL AREA ASSOCIATED WITH MID LEVEL SHORTWAVE MOVING ACROSS THE SOUTHEAST THROUGH THIS AFTERNOON. THIS SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH THE LOCAL AREA THIS EVENING. CLOUDS WILL CONTINUE TO INCREASE...BUT SHOULD REMAIN THIN ENOUGH INITIALLY TO NOT IMPACT THE TEMPS TOO MUCH. WINDS WILL SHIFT BACK AROUND TO THE S-SW THROUGH THIS AFTERNOON..REMAINING MORE ON SHORE AND SLIGHTLY HIGHER ALONG THE COAST. THIS WILL ALLOW AN INCREASE IN MOISTURE TRANSPORT INTO LOCAL AREA AS LATEST RUC/NAM PCP WATER VALUES UP TO NEAR 1 INCH REACHING JUST FAR ENOUGH NORTH INTO THE CAPE FEAR AREA BY 00Z. LATEST SREF DATA SHOWING BEST CHC OF MEASURABLE PCP JUST SOUTH OF CWA AND OFF SHORE BETWEEN 00-06Z THIS EVENING...BUT MOST OF AREA HAS LESS THAN 20% CHC. FOR NOW KEPT ONLY MENTION OF SPRINKLES IN FORECAST MAINLY ALONG THE COAST AND ADJACENT WATERS. MAY NEED TO ADJUST POP UP A LITTLE...BUT MOISTURE BELOW H85 STILL LACKING. BY WED MORNING...SHORTWAVE WILL EXIT THE COAST AND DRY AIR WILL BUILD IN BEHIND IT. CLOUD COVER WILL CLEAR OUT BY DAYBREAK. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...WEST TO NORTHWEST FLOW PREVAILS AT THE MID LEVELS THROUGH THE PERIOD AS HIGH PRESSURE WILL BE THE DOMINATE PLAYER AT THE SURFACE. WITH PRECIPITABLE WATERS HOVERING AROUND ONE HALF OF AN INCH...POPS WILL NOT BE AN ISSUE. REGARDING TEMPERATURES...THERMAL PROFILES REMAIN NEUTRAL FROM AN ADVECTION STANDPOINT WEDNESDAY WITH 850MB TEMPERATURES OF AROUND FOUR DEGREES CELSIUS WITH AN ASSIST FROM DOWNSLOPING SUPPORTING MID TO UPPER 60S ACROSS THE AREA. SOUTHWEST FLOW AHEAD OF THE NEXT SYSTEM WARMS PROFILES SOMEWHAT TRANSLATING TO 70-75 ACROSS THE AREA FOR THURSDAY. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 AM TUESDAY...NOT MUCH CHANGE WITH 0000 UTC MODEL CYCLES IN REGARDS TO THE EXTENDED PERIOD. THE GFS IS SHOWING A SLIGHTLY WETTER SCENARIO FOR LATE SATURDAY/EARLY SUNDAY WITH A SLIGHTLY STRONGER AND DEEPER MOISTURE FETCH FROM THE GULF OF MEXICO. ONLY ADJUSTED POPS TO REPRESENT A LATER TIME FRAME...IE SATURDAY NIGHT...WITH THIS PACKAGE AS IF ANYTHING THE FRONT HAS SLOWED A BIT. OTHERWISE...NO OTHER CHANGES. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... MVFR VSBYS LIKELY THIS MORNING BEFORE DAYBREAK AS T/TD SPREAD CONTINUES TO NARROW. VERY WEAK COLD FRONT MARKED MAINLY BY SCATTERED TO BROKEN MID TO UPPER LEVEL CLOUD DECK WILL MOVE ACROSS THE CWA AND OFFSHORE BY DAYBREAK. OTHER THAN A BRIEF SHIFT OF WINDS TO THE WEST AND NW AFTER DAYBREAK AND THE AFOREMENTIONED CLOUD COVER DO NOT EXPECT MUCH FROM THIS FEATURE. HOWEVER FOR THIS AFTERNOON AND TONIGHT AN H5 SHORT WAVE WILL APPROACH AND THEN MOVE ACROSS THE CWA. THIS WILL BRING A MORE SUBSTANTIAL INCREASE IN CLOUD COVER BEGINNING EARLY THIS AFTERNOON AND THE OFF CHANCE OF SOME SPRINKLES ALONG THE COAST TONIGHT. MODEL SOUNDINGS HAVE MOISTURE/CLOUD COVER CONFINED TO THE MID AND UPPER LEVELS SO DO NOT EXPECT ANY CIG ISSUES. CHANCES OF PRECIP TOO REMOTE FOR ANY VSBY CONCERNS OR MENTIONS IN THE TAFS. OTHER THAN MVFR VSBYS THIS MORNING...EXPECT VFR THRU THE REMAINDER OF THE PERIOD. THERE IS A POTENTIAL FOR IFR CONDITIONS IN NOCTURNAL LOW CLOUDS AND/OR FOG LATE WEDNESDAY AND THURSDAY NIGHTS. REDUCED VISIBILITIES AND LOWERED CIGS ALSO POSSIBLE FRIDAY AND SATURDAY AS RAIN CHANCES INCREASE. && .MARINE... NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 3 AM TUESDAY...LIGHT WINDS WITH SEAS GENERALLY AROUND 2 FT TODAY AND EARLY TONIGHT AS GRADIENT REMAINS SLACK. A VERY WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING BUT OTHER THAN A BRIEF SHIFT OF WINDS TO THE WEST AND NW DO NOT EXPECT MUCH FROM THIS FEATURE. SURFACE TROUGH INDUCED BY AN H5 SHORT WAVE WILL MOVE OFFSHORE TONIGHT...INCREASING SHIFTING WINDS TO THE WEST AT AROUND 10 TO 15 KTS BY DAYBREAK WEDNESDAY. SEAS MAY PICK UP AN EXTRA FOOT AS A RESULT...UP TO AROUND 3 FT WELL OFFSHORE AFTER MIDNIGHT. ISOLATED LIGHT SHOWER ACTIVITY MAY ALSO RESULT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...WESTERLY FLOW OF 10-15 KNOTS INITIALLY WILL BACK THROUGH THE PERIOD AS HIGH PRESSURE SKIRTS ACROSS THE SOUTHEAST AND EVENTUALLY MOVES OFF THE COAST. THE STRONGEST WINDS SHOW UP EARLY WEDNESDAY WITH 25 KNOTS AT 850MB ACROSS NORTHERN WATERS BUT WITH WATER TEMPERATURES ON THE MOVE AND WEAK OR NEUTRAL COLD AIR ADVECTION...TOUGH TO TRANSLATE TO THE SURFACE. SOUTHWEST FLOW OF 10 TO 15 KNOTS SHOULD PREVAIL BY THE END OF THE PERIOD. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY...CHANCES ARE IMPROVING FOR AT LEAST SMALL CRAFT CONDITIONS LATER SATURDAY WITH SYSTEM MOVING ACROSS TRENDING MORE DYNAMIC IN NATURE. HAVE INCREASED WINDS SLIGHTLY FOR THIS PERIOD OTHERWISE NO CHANGES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...REK SHORT TERM...SHK LONG TERM...SHK AVIATION...REK nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1047 AM CDT TUE MAR 11 2008 .UPDATE... ADJUSTED DEW POINT TEMPERATURES TO REFLECT CURRENT OBS...THEN INCREASED DAYTIME GRIDS TO REFLECT SLIGHTY HIGHER VALUES. RUC SUPPORTS THESE VALUES INTO THE EARLY EVENING. DID NOT ADJUST DAYTIME TEMPS. && .SHORT TERM... .PREV DISCUSSION... /ISSUED 623 AM CDT TUE MAR 11 2008/ AVIATION... EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT TWENTY FOUR HOURS...EXCEPT AT KSOA AND KBBD WHERE 3-4 SM VISIBILITIES WILL BE POSSIBLE THIS MORNING AS SOME LIGHT FOG DEVELOPS. LIGHT WINDS WILL BECOME MORE SOUTHERLY AT AROUND 10 TO 15 KNOTS THIS AFTERNOON. PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAR 11 2008/ DISCUSSION... CLEAR SKIES AND LIGHT WINDS AS THE SURFACE HIGH SETTLED IN HAS RESULTED IN VISIBILITIES STARTING TO LOWER ACROSS PART OF THE AREA. WILL KEEP THE MENTION OF FOG IN THROUGH THE MORNING HOURS. IN THE UPPER LEVELS...ANOTHER COMPACT...BUT RATHER INTENSE CIRCULATION IS CUTTING SOUTHEAST THROUGH NM. THIS LOW WILL MOVE ACROSS THE REGION TODAY. RUC ANALYSIS SHOWS 500MB TEMPS DOWN TO -20C OR COLDER. THIS MAY BE ENOUGH TO SET OFF A FEW ISOLATED SHOWERS AND/OR THUNDERSTORMS IN THE CONCHO VALLEY AND NORTHERN EDWARDS PLATEAU AS LAPSE RATES INCREASE TO 7.5 TO 8 C/KM. TEMPERATURES WILL INCREASE ACROSS THE AREA TODAY WITH SOUTHERLY FLOW...INCREASING THERMAL RIDGING. THE WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK...AS SOUTHERLY FLOW CONTINUES. AS TEMPERATURES INCREASE...RELATIVE HUMIDITY VALUES WILL DECREASE... AND WILL RESULT IN ELEVATED FIRE DANGER WHICH WILL BE DISCUSSED IN FURTHER DETAIL BELOW. TEMPERATURES WILL WARM INTO THE 80S BY THURSDAY AND FRIDAY. ON FRIDAY...SURFACE WINDS MAY INCREASE SIGNIFICANTLY. AN UPPER LEVEL TROUGH IS FORECAST TO MOVE WEST TO EAST ACROSS THE REGION. AS THIS TAKES PLACE...A SURFACE LOW IS FORECAST TO DEEPEN AND TRANSLATE TO THE EAST OVER OK. THIS WILL INCREASE WESTERLY WINDS...AND WITH 700MB WINDS AT 40 OR 50 KNOTS COMBINED WITH GOOD MIXING...WE MAY SEE WINDS OF 25 TO 35 MPH WITH GUSTS AS HIGH AS 40 MPH. THIS WILL ALSO DRIVE THE DRYLINE EAST THROUGH THE AREA...AND WITH DOWNSLOPING WINDS... DRIER AIR...WE MAY SEE TEMPERATURES REACHING INTO THE UPPER 80S OR EVEN LOWER 90S IN SOME LOCATIONS. CHANCES FOR PRECIP ASSOCIATED WITH THIS FRONT ARE NOT HIGH ENOUGH FOR POPS TO BE INSERTED. A COLD FRONT WILL FOLLOW THIS SYSTEM SATURDAY...BRINGING TEMPERATURES CLOSER TO NORMAL FOR THE WEEKEND. ANOTHER UPPER LEVEL LOW IS EXPECTED TO IMPACT THE AREA DURING THE EARLY PART OF NEXT WEEK...GIVING THE AREA A CHANCE FOR SHOWERS AND THUNDERSTORMS...DEPENDING ON THE AMOUNT OF MOISTURE RETURN AND PATH OF THE UPPER LEVEL SYSTEM. HAVE KEPT THE SLIGHT CHANCE OF PRECIP IN FOR NOW...MAINLY OVER THE EASTERN 2/3 OF THE CWA. FIRE WEATHER... TEMPERATURES WILL WARM DURING THE SECOND HALF OF THE WORK WEEK ACROSS THE AREA AS A THERMAL RIDGE INCREASES OVER THE AREA. FIRE WEATHER DANGERS WILL RISE AS MINIMUM RELATIVE HUMIDITY VALUES FALL. CURRENTLY...THE DAY WITH THE HIGHEST POTENTIAL FOR REACHING CRITICAL FIRE WEATHER VALUES IS FRIDAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA DEEPENING A SURFACE LOW TO THE NORTH OF OUR AREA...AND BRING STRONG MID LEVEL WINDS WITH IT AS WELL. THIS PATTERN IS FAVORABLE FOR PUSHING THE AREA INTO EXTREMELY CRITICAL VALUES CONCERNING FIRE WEATHER. MIXING WILL BE STRONG...AND MAY RESULT IN WIND GUSTS TO 40 MPH OR GREATER OUT OF THE WEST FOR MUCH OF THE AREA. THESE STRONG WEST WINDS WILL ALSO PUSH A DRYLINE THROUGH THE AREA WHICH WILL CAUSE TEMPERATURES TO RISE INTO THE UPPER 80S TO NEAR 90. THIS WILL ALLOW RELATIVE HUMIDITY VALUES TO FALL TO LESS THAN 10 PERCENT ACROSS WESTERN PARTS OF THE CWA. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 67 49 77 53 / 10 0 0 10 SAN ANGELO 67 46 76 53 / 10 0 0 10 JUNCTION 69 46 75 54 / 10 0 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 12/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 623 AM CDT TUE MAR 11 2008 .AVIATION... EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT TWENTY FOUR HOURS...EXCEPT AT KSOA AND KBBD WHERE 3-4 SM VISIBILITIES WILL BE POSSIBLE THIS MORNING AS SOME LIGHT FOG DEVELOPS. LIGHT WINDS WILL BECOME MORE SOUTHERLY AT AROUND 10 TO 15 KNOTS THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAR 11 2008/ DISCUSSION... CLEAR SKIES AND LIGHT WINDS AS THE SURFACE HIGH SETTLED IN HAS RESULTED IN VISIBILITIES STARTING TO LOWER ACROSS PART OF THE AREA. WILL KEEP THE MENTION OF FOG IN THROUGH THE MORNING HOURS. IN THE UPPER LEVELS...ANOTHER COMPACT...BUT RATHER INTENSE CIRCULATION IS CUTTING SOUTHEAST THROUGH NM. THIS LOW WILL MOVE ACROSS THE REGION TODAY. RUC ANALYSIS SHOWS 500MB TEMPS DOWN TO -20C OR COLDER. THIS MAY BE ENOUGH TO SET OFF A FEW ISOLATED SHOWERS AND/OR THUNDERSTORMS IN THE CONCHO VALLEY AND NORTHERN EDWARDS PLATEAU AS LAPSE RATES INCREASE TO 7.5 TO 8 C/KM. TEMPERATURES WILL INCREASE ACROSS THE AREA TODAY WITH SOUTHERLY FLOW...INCREASING THERMAL RIDGING. THE WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK...AS SOUTHERLY FLOW CONTINUES. AS TEMPERATURES INCREASE...RELATIVE HUMIDITY VALUES WILL DECREASE... AND WILL RESULT IN ELEVATED FIRE DANGER WHICH WILL BE DISCUSSED IN FURTHER DETAIL BELOW. TEMPERATURES WILL WARM INTO THE 80S BY THURSDAY AND FRIDAY. ON FRIDAY...SURFACE WINDS MAY INCREASE SIGNIFICANTLY. AN UPPER LEVEL TROUGH IS FORECAST TO MOVE WEST TO EAST ACROSS THE REGION. AS THIS TAKES PLACE...A SURFACE LOW IS FORECAST TO DEEPEN AND TRANSLATE TO THE EAST OVER OK. THIS WILL INCREASE WESTERLY WINDS...AND WITH 700MB WINDS AT 40 OR 50 KNOTS COMBINED WITH GOOD MIXING...WE MAY SEE WINDS OF 25 TO 35 MPH WITH GUSTS AS HIGH AS 40 MPH. THIS WILL ALSO DRIVE THE DRYLINE EAST THROUGH THE AREA...AND WITH DOWNSLOPING WINDS... DRIER AIR...WE MAY SEE TEMPERATURES REACHING INTO THE UPPER 80S OR EVEN LOWER 90S IN SOME LOCATIONS. CHANCES FOR PRECIP ASSOCIATED WITH THIS FRONT ARE NOT HIGH ENOUGH FOR POPS TO BE INSERTED. A COLD FRONT WILL FOLLOW THIS SYSTEM SATURDAY...BRINGING TEMPERATURES CLOSER TO NORMAL FOR THE WEEKEND. ANOTHER UPPER LEVEL LOW IS EXPECTED TO IMPACT THE AREA DURING THE EARLY PART OF NEXT WEEK...GIVING THE AREA A CHANCE FOR SHOWERS AND THUNDERSTORMS...DEPENDING ON THE AMOUNT OF MOISTURE RETURN AND PATH OF THE UPPER LEVEL SYSTEM. HAVE KEPT THE SLIGHT CHANCE OF PRECIP IN FOR NOW...MAINLY OVER THE EASTERN 2/3 OF THE CWA. FIRE WEATHER... TEMPERATURES WILL WARM DURING THE SECOND HALF OF THE WORK WEEK ACROSS THE AREA AS A THERMAL RIDGE INCREASES OVER THE AREA. FIRE WEATHER DANGERS WILL RISE AS MINIMUM RELATIVE HUMIDITY VALUES FALL. CURRENTLY...THE DAY WITH THE HIGHEST POTENTIAL FOR REACHING CRITICAL FIRE WEATHER VALUES IS FRIDAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA DEEPENING A SURFACE LOW TO THE NORTH OF OUR AREA...AND BRING STRONG MID LEVEL WINDS WITH IT AS WELL. THIS PATTERN IS FAVORABLE FOR PUSHING THE AREA INTO EXTREMELY CRITICAL VALUES CONCERNING FIRE WEATHER. MIXING WILL BE STRONG...AND MAY RESULT IN WIND GUSTS TO 40 MPH OR GREATER OUT OF THE WEST FOR MUCH OF THE AREA. THESE STRONG WEST WINDS WILL ALSO PUSH A DRYLINE THROUGH THE AREA WHICH WILL CAUSE TEMPERATURES TO RISE INTO THE UPPER 80S TO NEAR 90. THIS WILL ALLOW RELATIVE HUMIDITY VALUES TO FALL TO LESS THAN 10 PERCENT ACROSS WESTERN PARTS OF THE CWA. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 67 49 77 53 / 10 0 0 10 SAN ANGELO 67 46 76 53 / 10 0 0 10 JUNCTION 69 46 75 54 / 10 0 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/28 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 250 PM EDT TUE MAR 11 2008 .SYNOPSIS...SHORTWAVE PRODUCING SCATTERED LIGHT SHOWERS ACROSS SE AL AND S GA CONTINUES TO PUSH E. ANOTHER SHORTWAVE EVIDENT ON H2O VAPOR SAT LOOP AND 400 MB RUC PRESENTLY LOCATED OVER N TX. LOW AND MID CLOUDINESS CONTINUES OVER MUCH OF THE SE US IN RESPONSE TO UPSTREAM ENERGY AS WELL AS WEAK ISENTROPIC LIFT ACROSS THE AREA. TEMPS RANGE FROM THE MID 60S TO LOWER 70S WITH DEW POINTS IN THE MID 50S. .SHORT TERM...GFS AND NAM FCST HIGHEST POPS THIS EVENING ACROSS SE GA AS SHORTWAVE CONTINUES TO MOVE E WITH ADDITIONAL LOW-LEVEL SUPPORT PROVIDED BY WEAK SEABREEZE. ENUF LOW-LEVEL MOISTURE AND LIGHT ENUF WINDS FOR SOME FOG AGAIN TONIGHT. HOWEVER...DRIER AIR WILL BE FILTERING IN AFTER MIDNIGHT...AND EXTENT OF FOG SHOULD BE LIMITED. NEXT SHORTWAVE WILL MOVE INTO THE AREA WED AFTN...BUT MOSTLY DRY ATMOSPHERIC COLUMN SHOULD PRECLUDE ANY ADDITIONAL PRECIP. DAYTIME HIGHS WILL REMAIN NEAR NORMAL WITH NIGHTTIME LOWS SLIGHTLY BELOW NORMAL. .LONG TERM...NEXT STORM SYSTEM STILL PROGGED TO MOVE ACROSS THE SE US LATE THIS WEEK AND INTO THE 1ST HALF OF THE WEEKEND. BOTH GFS AND NAM INDICATING THAT A SMALL BUT RATHER POTENT SHORTWAVE WILL MOVE ACROSS NE FL WELL AHEAD OF THE ACTUAL SFC FRONT...WITH A GOOD SHOT OF SHOWERS AND SOME TSTMS. LOOKING AT THE ACTUAL STRENGTH OF THIS SHORTWAVE...THE AMOUNT OF VORTICITY AND LIFT APPEARS TO BE OVERDONE...BUT THERE IS FAIR AGREEMENT BETWEEN THE MODELS. WILL CAP POPS AT 40% FOR NOW. ALTHO THERE APPEARS TO BE A GOOD AMOUNT OF INSTABILITY BY SAT ACROSS THE AREA...GFS HAS MOST OF THE FRONTAL PRECIP TIED UP AROUND COMPLEX AREA OF LOW PRESSURE N OF THE AREA. HAVE MADE ONLY MINOR ADJUSTMENTS TO TEMPS WITH VALUES NEAR TO ABOVE NORMAL THRU THE PERIOD. && .AVIATION...EXPECT DEVELOPING MVFR AT ALL SITES THIS EVENING AS LOW CLOUDS MOVE IN FROM THE WSW. HAVE TEMPO LIFR POSSIBLE 08-12Z ALL SITES DUE TO LOW CIGS. VCSH SHOULD SUFFICE UNTIL PRECIP DRAWS CLOSER TO TAF SITES AND THEN MAY INCLUDE TEMPO WHEN TIMING IS MORE PREDICTABLE. && .MARINE...NO HEADLINES EXPECTED UNTIL LATE FRI. STRONG POST FRONTAL NNE SURGE EXPECTED SUN THROUGH MON WITH SCA CONDITIONS LIKELY OFFSHORE. && .FIRE WX...HAVE RAISED A RED FLAG FOR OUR N FL ZONES WED DUE TO EXTENDED DURATIONS OF LOW RHS AND A WATCH THU FOR ALL INLAND NE FL DUE TO LOW RHS. && .PRELIMINARY POINT TEMPS/POPS... AMG 43 71 41 74 / 20 0 0 0 SSI 50 68 48 69 / 50 0 0 0 JAX 48 72 45 74 / 30 0 0 0 SGJ 52 70 49 71 / 30 0 0 0 GNV 49 74 44 75 / 10 0 0 0 OCF 50 75 45 75 / 10 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ CARROLL/ENYEDI/KEEGAN fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 110 PM EDT TUE MAR 11 2008 .AVIATION... AM ST DECK CONTS TO LIFT/MIX INTO SCT SC FIELD AROUND 2.5KFT AT 18 UTC ACRS NRN IN. CONTINUED MIXOUT OF MOISTURE ANTICIPATED THIS AFTERNOON LEAVING ONLY HIGH THIN CI OVERNIGHT. NAM MODEL INDICATES SATURATION/STRATUS POTENTIAL TOWARD DAYBREAK AGAIN WED AM...THOUGH MAGNITUDE OF MOISTURE APPEARS OVERDONE GIVEN LACK OF SUBSTANTIAL MIXING IN BL. FOR NOW WILL FORGO AM ST LYR...WITH ONLY PD OF HIGH END MVFR VSBY IN BR AT WORST WITH TEMPS HOLDING AOA XOVER AND MIDLING SNOWCOVER. && .SHORT TERM (TODAY AND TONIGHT)... SFC HIGH IN CONTROL OF THE REGION THIS MORNING...CENTERED JUST EAST OF STL AS OF THIS WRITING. NORTHWEST FLOW ALOFT WITH TROUGH AXIS NEAR OR ACROSS THE EASTERN COASTLINE. SKIES BEGAN TO CLEAR OVERNIGHT ALLOWING FOR DECENT RAD COOLING FOR MOST OF THE REGION...AND IN COMBO WITH LIGHT WINDS AND AMPLE LOW LEVEL MOISTURE HAVE CREATED STRONG CONDITIONS FOR FOG DEVELOPMENT EARLY THIS MORNING. WILL CONTINUE TO MONITOR FOR ANY SIGNIFICANT DROPS IN VSBY...ESPECIALLY ACROSS THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA. THE LATEST RUC 13 RUN WOULD SUGGEST THAT VSBYS WOULD NEAR DENSE FOG CRITERIA BY 10Z...WILL WATCH THE CLEARING OF THE CLOUDS...TIMING...AND VSBY DROPS AFTERWARD TO SEE IF A DENSE FOG ADVISORY WILL BE NEEDED LATER THIS MORNING. GFS APPEARS TO HAVE WAY TOO MUCH MOISTURE WITH THE FAST MOVING CLIPPER-LIKE SYSTEM THAT DRIVES THROUGH THE GREAT LAKES THIS EVENING AND OVERNIGHT. THE DRIER NAM MOISTURE FIELDS SEEM A BETTER FIT AS THE SYSTEM HAS NO WAY TO TAP THE GULF. EXPECT NEAR FULL SUN FOR THIS MORNING INTO THE EARLY AFTN...MOST IF NOT ALL OF THE REMAINING SNOWPACK SHOULD BE RELEASED IN THE NEXT 24HRS. THE SNOWPACK HAD LITTLE AFFECT ON TEMPS TODAY WITH HIGHS IN THE LOWER 40S WHERE SNOW LIES...WITH THE INCREASING SUN ANGLE HAVE NOT ACCOUNTED FOR THE OLDER SNOWFIELD COOLING AS MUCH AS NORMALLY WOULD. MOS EQUATIONS MAY STILL BE USING WINTER SCHEME...AND WOULD NOT ACCOUNT FOR THE STRONGER MID MARCH SUN ANGLE AS WELL...ANOTHER REASON TO GO ABV MOS IN THE SOUTHEAST...THE SOUTHWEST WINDS WILL HELP IN THIS MATTER AS WELL WITH MID 40S OR HIGHER ACROSS MUCH OF THE FORECAST AREA. MID AND UPPER LEVEL CLOUDS ASSOCIATED WITH THE SYSTEM MOVING TO THE NORTH AND EAST OF THE REGION IN THE EVENING. WEAK SFC TROUGH PUSHING THROUGH AFTER MIDNIGHT...WITH JUST A WIND SHIFT TO THE NORTH. EVEN WITH THE NORTH WINDS IN THE EARLY MORN...LOWS WILL BE NEAR NORMAL IN THE UPPER 20S. && .LONG TERM (WEDNESDAY THROUGH MONDAY)... TEMPERATURES WILL CONTINUE TO MODERATE INTO THURSDAY AS SOUTH TO SOUTHWEST WINDS INCREASE AHEAD OF AN APPROACHING SURFACE LOW AND FRONT. HIGHS SHOULD BE ABLE TO REACH NEAR 50F WITH LOW LEVEL FLOW 40 TO 50 KNOTS. KEPT A CHANCE FOR RAIN LATE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THE FRONT SHOULD REACH THE AREA EARLY THURSDAY...AND THEN A WAVE SHOULD DEVELOP ALONG THE FRONT OVER MISSOURI AND MOVE EAST THURSDAY NIGHT. OVERALL THE GFS HAS BACKED OFF BRINGING MUCH COLDER AIR BEHIND THE FRONT THURSDAY NIGHT IN LIEU OF THE WAVE ALONG THE FRONT. THEREFORE...ADDED A MIX OF RAIN AND SNOW LATE THURSDAY NIGHT. THERMODYNAMIC PROFILES CLOSE TO A RAIN AND SNOW MIX. PLACED HIGHER RAIN/SNOW CHANCES OVER SOUTHEAST AREAS WHERE BEST FRONTAL LIFT WILL OCCUR...SO BEST CHANCE FOR RAIN BASICALLY MARION TO LIMA. A SECOND LOW SHOULD MOVE EAST NORTHEAST ALONG THE FRONT SATURDAY. THE BIG CHALLENGE HERE IS HOW FAR NORTH THE PRECIPITATION WILL SPREAD. RAISED SNOW CHANCES TO 50 PERCENT IN THE SOUTH...WITH 25 TO 30 PERCENT IN THE NORTH. A LARGE ANTICYCLONE OVER SOUTH CENTRAL CANADA SHOULD HELP WITH DRY AIR ENTRAINMENT AS A COLD AND DRY NORTHEAST FETCH SETS UP OVER THE GREAT LAKES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...SCHOTT LONG TERM...SKIPPER AVIATION...MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 438 PM EDT TUE MAR 11 2008 .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN ACROSS THE CONUS/SRN CANADA. IN THE DOMINANT NRN BRANCH...A SHORTWAVE WAS DIVING THRU THE UPPER GREAT LAKES. ANOTHER SHORTWAVE WAS HAS RECENTLY MOVED ONSHORE OVER THE PACIFIC NW. THIS WILL BE THE FEATURE OF INTEREST FOR THE WEATHER HERE WED/WED NIGHT. STRONG ISENTROPIC ASCENT AHEAD OF THE UPPER GREAT LAKES SHORTWAVE DID MANAGE TO OVRECOME THE DRY LOW/MID LEVELS TO RESULT IN A PERIOD OF -SN EARLIER THIS AFTN OVER THE FAR ERN FCST AREA. && .SHORT TERM (TONIGHT THRU WED NIGHT)... SFC COLD FRONT IS CURRENTLY MOVING S ACROSS THE FCST AREA...AND IT WILL CONTINUE TO HEAD S TONIGHT AS HIGH PRES SLIDES ACROSS NRN ONTARIO. POSTFRONTAL STRATOCU DECK IS DROPPING TOWARD NRN LAKE SUPERIOR ATTM. OBS IN ONTARIO HAVE INDICATED A FEW FLURRIES WITH THESE CLOUDS...SO THERE MAY BE A FEW FLURRIES THIS EVENING ACROSS THE NW AND NCNTRL/NE FCST AREA AS BKN CLOUD DECK SETTLES S. BEST CHANCE WILL BE OVER THE E WHERE SHARPER LOW-LEVEL CYCLONIC FLOW WILL EXIST FOR A SHORT TIME THIS EVENING. OTHERWISE...TEMPS AT THE INVERSION BASE DROPPING TO AROUND -12C WILL BE MARGINAL FOR LES LATER TONIGHT. COMBINED WITH FLOW BECOMING ANTICYCLONIC...OPTED TO INCLUDE JUST A MENTION OF FLURRIES OVER THE NCNTRL FOR THE OVERNIGHT. AS FOR TEMPS...WENT BLO GUIDANCE OVER THE W WHERE SFC HIGH PRES RIDGE WILL ARRIVE. LIGHT WINDS AND PROBABLY LITTLE IN THE WAY OF CLOUD COVER SHOULD ALLOW FOR DECENT RADIATIONAL COOLING. WED/WED NIGHT...ATTENTION TURNS TO THE SHORTWAVE CURRENTLY OVER THE PACIFIC NW. MODELS ARE IN GOOD AGREEMENT DELAYING SNOW ARRIVAL OVER WRN UPPER MI UNTIL THE AFTN HRS...BUT IT`S ALWAYS A CHALLENGE TO TIME THE EROSION OF DRY AIR WHEN WAA/ISENTROPIC ASCENT DEVELOP. GIVEN THE AMOUNT OF DRY AIR THAT THE NAM/GFS INDICATE...CERTAINLY DO NOT EXPECT ANY SNOW BEFORE THE AFTN HRS. SINCE THERE IS GOOD MODEL AGREEMENT SHOWING MEASURABLE PCPN REACHING THE W THIRD TO HALF OF UPPER MI BY 00Z...DECIDED TO CARRY SLIGHT CHC POPS TO KMQT/KIMT LATE AFTN WITH A TREND UP TO LIKELY POPS FAR W. DECENT PERIOD OF ISENTROPIC ASCENT (290K SFC) THEN SPREADS ACROSS THE FCST AREA WED NIGHT. WITH MIXING RATIOS AROUND 3G/KG AND 6-9HRS OF ASCENT...EXPECT ACCUMULATIONS GENERALLY AROUND 3 INCHES IN MOST AREAS. NOT OUT OF THE QUESTION TO SEE A BIT MORE SINCE UPWARD MOTION NICELY INTERSECTS LAYER OF FAVORABLE DENDRITIC SNOW GROWTH TEMPS. .LONG TERM (12Z THU THROUGH 00Z WEDNESDAY)... NOT TOO EXCITED ABOUT PRECIPITATION POTENTIAL AFTER 12Z ON THURSDAY AS DRIER AIR WORKS IN ALOFT...THOUGH SOME LINGERING SNOW WILL STILL BE FALLING ACROSS THE EAST...THOUGH CAN/T RULE OUT SNOW ELSEWHERE. PRECIP. TYPE SHOULD REMAIN SNOW BEFORE A MIX OF RAIN/SNOW TAKES OVER IN THE AFTN DUE TO SFC HEATING. OPTED TO PULL POPS FROM THE EAST AS LIFT APPEARS TO BE MORE FOCUSED OVER THE WEST. FOR THU EVENING INTO FRI MORNING MOISTURE PROFILES HAVE THE LOOK OF A FREEZING DRIZZLE SCENARIO...HOWEVER ANTECENDENT ICE CRYSTALS MAY JUST KEEP ANY PRECIP. THAT FALLS SNOW. LEFT THE FCST THE SAME FOR THU EVENING/FRI. AS THE LOW PULLS AWAY THERE IS THE POTENTIAL FOR LAKE EFFECT DEVELOPMENT FRI EVENING AS COLDER AIR...850 TEMPS -12 TO -14C...FILTERS INTO THE WEST AND EVENTUALLY THE WHOLE CWA BY SATURDAY MORNING...THIS ALONG WITH PERSISTENT NORTHERLY FLOW SHOULD ALLOW FOR SOME LES TO DEVELOP. NOT EXCITED ABOUT SNOW AMOUNTS...EXPECT LITTLE ACCUMULATION IF ANY THROUGH SAT AFTN. THEREAFTER HIGH PRESSURE BUILDS INTO THE FA FROM THE NORTH AND REMAINS THROUGH MON MORNING. LOOKING AHEAD THERE IS THE POTENTIAL FOR A STRONG MID WEEK SYSTEM THOUGH THERE ARE SIGNIFICANT MODEL DIFFERENCES BETWEEN THE GFS AND EC SOLUTIONS. PART OF THE DIFFERENCES APPEAR DUE TO THE HIGHER AMPLITUDE RIDGE OVER THE EAST COAST IN THE GFS SOLUTION ALLOWING THE WESTERN TROUGH TO DIG FURTHER SOUTH ALLOWING FOR A PLAINS LOW TO DEVELOP AND MOVE TO LOWER MI BY TUESDAY. THE EC SOLUTION YIELDS A MORE ZONAL FLOW PATTERN WHICH WOULD SUGGEST A WEAKER NORTHERN STREAM SYSTEM FOR MID WEEK. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... IN THE WAKE OF A COLD FRONT DROPPING THRU THE UPPER GREAT LAKES...MVFR STRATOCU DECK SHOULD DEVELOP IN NRLY FLOW THIS AFTN...BUT MORE LIKELY TOWARD EVENING AS MVFR CLOUDS N OF LAKE SUPERIOR ARRIVE. WHILE THERE MIGHT BE A FEW FLURRIES TONIGHT...AIRMASS IS NOT COLD ENOUGH FOR ANY LAKE EFFECT SHSN THAT WOULD BE HEAVY ENOUGH TO REDUCE VIS. ARRIVAL OF HIGH PRESSURE RIDGE SHOULD SHOULD CAUSE CLOUDS TO BREAK UP INTO A SCATTERED DECK AT KCMX TONIGHT. EXPECT A MORE PERSISTENT CLOUD DECK AT KSAW INTO WED MORNING DUE TO N TO NE WINDS BRINGING LAKE EFFECT CLOUDS OFF THE SOMEWHAT ICE FREE EASTERN LAKE SUPERIOR. NEXT LOW PRES TROF ADVANCING TOWARD THE UPPER GREAT LAKES WILL BRING -SN AND MVFR CONDITIONS TO KCMX BEYOND THIS FCST PERIOD (WED AFTN). && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT PERIOD OF NRLY 15-25KT WINDS THIS EVENING AHEAD OF HIGH PRES SLIDING ACROSS NRN ONTARIO. WINDS WILL THEN DIMINISH OVERNIGHT/WED MORNING AS HIGH PRES RIDGE SAILS ACROSS LAKE SUPERIOR. LIGHT WINDS WILL BE SHORT LIVED AS PRES GRADIENT TIGHTENS WED AFTN/NIGHT DUE TO LOW PRES TRACKING E TOWARD NRN ONTARIO. SHOULD SEE SRLY WINDS REACH 20-30KTS WED NIGHT OVER THE E HALF OF LAKE SUPERIOR BEFORE DIMINISHING THU. AFTER THU...WINDS SHOULD REMAIN UNDER 20KT FOR THE REMAINDER OF THE FCST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/SHORT TERM...ROLFSON LONG TERM...DJP AVIATION..ROLFSON MARINE...ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 123 PM EDT TUE MAR 11 2008 .UPDATE...PRECIP HAS ARRIVED IN PLN IN THE FORM OF RAIN...SOMEWHAT UNEXPECTED. SURFACE HEATING HAS BOOSTED TEMPS INTO THE MID OR EVEN UPPER 30S. EVAP COOLING SHOULD EAT THE SURFACE-BASED WARM LAYER QUICKLY...BUT THAT HASN/T HAPPENED AT PLN YET. SO WILL UPDATE TO ADD RAIN TO NORTHERN LOWER. WILL ALSO DIMINISH PRECIP LATE IN THE DAY...ESPECIALLY IN EASTERN UPPER MI...AS LOW/MID CLOUDS MAKING SOUTHWARD PROGRESS ACROSS SUPERIOR HAVE LITTLE PRECIP. REDUCED SNOW ACCUMS TODAY FOR THE ABOVE REASONS...LESS THAN AN INCH EVERYWHERE. JZ && .AVIATION...SPOTTY SNOW OR MIXED RAIN/SNOW SHOWERS EXPECTED NEAR ALL THE TAF SITES OVER THE NEXT FEW HOURS...AND THEN AGAIN LATE THIS AFTERNOON INTO THE EVENING...THANKS TO LOW PRESSURE PASSING BY TO OUR NORTH. THANKS TO SOME INSTABILITY ALOFT...VERY BRIEF IFR CONDITIONS ARE POSSIBLE...BUT WILL NOT PLACE IN THE TAFS FOR NOW. DRIER AIR WILL ARRIVE FROM THE NORTH TONIGHT AS LOW PRESSURE MOVES AWAY FROM LAKE HURON...VFR CONDITIONS EXPECTED WEDNESDAY. JZ && .PREVIOUS DISCUSSION...ISSUED 1042 AM TUE MAR 11... UPDATE...1004MB SURFACE LOW NORTH OF SUPERIOR THIS MORNING. MID LEVEL RETURNS INCREASING ACROSS UPPER MI. SUSPECT SOME OF THAT IS REACHING THE GROUND...THOUGH SURFACE OBS NOT YET INDICATIVE OF THAT. IR SATELLITE IMAGERY SHOWS A WELL-DEFINED SHORTWAVE MOVING EAST FROM THE KEWEENAW...A SECOND WAVE IS IMPLIED IN AN AREA OF MID CLOUDS ALONG MN/ONTARIO BORDER. PRECIP TRENDS ARE THE MAIN CONCERN FOR TODAY. THE 2ND WAVE WILL ACTUALLY WILL THE DOMINANT ONE DYNAMICALLY... DIGGING TOWARD CENTRAL LOWER MI. BUT MOISTURE AVAILABILITY IS LESS FARTHER SOUTH...WITH MORE SUSTAINED AND STRONGER ISENTROPIC ASCENT TO THE NORTH. IN ADDITION...MODELS SHOW A BETTER COMBINATION OF STEEP MID-LAPSE RATES ABOVE 650MB...AND LOW LEVEL MOISTURE...ACROSS THE NORTH. THIS IS CERTAINLY INDICATIVE IN PRECIP TENDING TO BE SHOWERY. WILL PLAY UP NUMEROUS SNOW SHOWERS IN EASTERN UPPER MI AND FAR NORTHERN LOWER MI THIS AFTERNOON...WITH SCT POPS TO THE SOUTH...AS MID LEVEL INSTABILITY WILL ONLY OVERCOME LOW LEVEL DRY AIR IN SPOTS. ACCUMS AROUND AN INCH IN EASTERN UPPER MI...LESS THAN THAT SOUTH. MAX TEMPS LOOK OK...MAY NEED TO KICK UP A DEGREE OR TWO IN SPOTS. ZOLTOWSKI DISCUSSION...LARGE SCALE PATTERN LOOKING PROGRESSIVE THIS WEEK WITH A BROAD 4-5 WAVE HEMISPHERIC PATTERN. REMNANTS OF A COUPLE PACIFIC ORIGIN SHORT WAVE TROUGHS WILL SWING THROUGH THE WESTERN GREAT LAKES OVER THE NEXT SEVERAL DAYS...ONE TODAY COMING OUT OF MANITOBA THIS MORNING...AND A SECOND WAVE COMING ONSHORE THIS MORNING LOOKS TO IMPACT THE AREA IN THE THURSDAY TIME FRAME. BEYOND THAT PATTERN BECOMES BASICALLY SPLIT/ZONAL FOR THE WEEKEND...SOME HINTS AT A -NAO TYPE PATTERN DEVELOPING WITH RISING HEIGHTS ACROSS ICELAND/GREENLAND...BUT PROBABLY IN NAME ONLY AS THE TYPICAL RESPONSE OVER NORTH AMERICA (E.G., COLD FOR US) DOES NOT APPEAR TO BE IN THE CARDS WITH POLAR VORTEX BOTTLED UP ABOVE 60N...AND A POSSIBLE RE-APPEARANCE OF THE SOUTHEAST U.S. RIDGE AS HEIGHTS FALL ACROSS THE SOUTHWESTERN STATES. A PROBABLE SET UP FOR MORE COMPLICATED FORECAST ISSUES NEXT WEEK. IN THE MEANTIME...HIGH PRESSURE SINKING SOUTH OF THE STATE THIS MORNING...WITH HEIGHT FALLS ASSOCIATED WITH MANITOBA SHORT WAVE/JET STREAK DIVING TOWARD THE WESTERN LAKES. SURFACE PRESSURES FALLING IN RESPONSE TO THIS (3-4MB/3H PRESSURE FALLS ACROSS WESTERN ONTARIO/NORTHERN MN)....ALLOWING ASSOCIATED SURFACE LOW OVER EASTERN MANITOBA TO DROP SOUTHEAST TOWARD LAKE SUPERIOR. SURFACE LOW FORECAST TO SLIDE ACROSS LAKE SUPERIOR TODAY...WHILE MAIN SHORT WAVE ENERGY COMES RIGHT ACROSS THE LOWER PENINSULA. SO FIRST FORECAST PROBLEM THIS MORNING WILL DEAL WITH PRECIPITATION POTENTIAL WITH THIS SYSTEM. DEEP LAYER RIDGING BUILDS INTO THE WESTERN LAKES FOR WEDNESDAY...THEN NEXT SERIES OF HEIGHT FALLS ARRIVES WEDNESDAY NIGHT/THURSDAY...WHICH IS FORECAST PROBLEM NUMBER TWO. TODAY/TONIGHT...HIGH CLOUDS INVADING NORTHERN MI EARLY THIS MORNING FROM THE NORTHWEST AHEAD OF APPROACHING SHORT WAVE TROUGH. CLOUD TOPS HAVE BEEN COOLING/EXPANDING ACROSS MN AND WESTERN ONTARIO...AND STARTING TO GET INCREASING MOISTURE IN 900-500MB LAYER PER GOES SOUNDER WATER VAPOR IMAGERY. BUT MUCH OF THAT MOISTURE LIKELY ABOVE 700MB WITH JUST A HANDFUL OF OBSERVATIONS OF CLOUDS BELOW 12K FEET THROUGH 06Z (MOSTLY ACROSS ONTARIO). A FEW HIGH BASED RADAR RETURNS HEADED INTO LAKE SUPERIOR PER ONTARIO RADAR COMPOSITE...BUT NO PRECIPITATION AT THE ONSET OF THE FORECAST PERIOD. FORECAST PROBLEM OF THE DAY IS TIMING OF INCREASED SATURATION AS STRONGER DYNAMICS COME INTO PLAY (GOOD QG FORCING AND LFQ JET DYNAMICS). LIFT IS NOT THE PROBLEM...THE QUESTION WILL IT BE ENOUGH TO MOISTEN WHAT IS ADMITTEDLY A RELATIVELY DRY ANTECEDENT AIR MASS. GUIDANCE IS STILL SPLIT ON THIS ISSUE...WITH THE NAM REMAINING DRY (SHUNTING BEST DEEP LAYER MOISTURE QUICKLY EAST OF THE FORECAST AREA THIS MORNING)...AND THE GFS SHOWING BETTER MOISTENING WITH TIME AS STRONGER FORCING ARRIVES. ECMWF/UKMET/RUC THROWING SUPPORT TOWARD THE GFS...AND AS WATER VAPOR IMAGERY SHOWS UPSTREAM WAVE TAKING ON A BETTER ORGANIZED (LESS SHEARED) APPEARANCE...GETTING COLDER CLOUD TOPS NOW DEVELOPING IN THE VICINITY OF LAKE WINNIPEG. GIVEN THE STRENGTH OF THE FORCING HAVE TO BELIEVE THAT DEEP LAYER RH WILL IMPROVE THROUGH THE DAY TO SUPPORT A THREAT OF PRECIPITATION ACROSS THE ENTIRE FORECAST AREA... THOUGH SEE NO NEED TO CHANGE OUR POP DISTRIBUTION WHICH HAS BEEN CONSISTENTLY HIGHER TO THE NORTH. NOT EXPECTING PRECIP CHANCES ACROSS NORTHERN LOWER UNTIL THE AFTERNOON. LAPSE RATES EXPECTED TO BE FAIRLY STEEP ABOVE 750MB...SUPPORTING THE POSSIBILITY OF SOME ELEVATED CONVECTIVE/SHOWERY ELEMENTS DEVELOPING. PRECIP TYPE WILL DEPEND ON DEPTH OF SURFACE BASED WARM LAYER...NAM TRYING TO SHOVE A PRETTY DECENT THERMAL RIDGE INTO THE FORECAST AREA LATER TODAY (925MB TEMPERATURES 4-6C WARMER THAN GFS)...THIS LOOKS OVERDONE BASED ON INITIALIZATION AND 05Z AIRCRAFT SOUNDING OUT OF MPX WHICH INDICATED A 925MB TEMP OF +2C WHEN THE NAM HAD +5C PROGGED AT 06Z. SURFACE TEMPERATURES SHOULD WARM IN TO THE MID 30S AT LEAST...CURRENT FORECAST IS ALL SNOW EVERYWHERE AND THINK THAT`S THE WAY TO GO AT THIS TIME. WILL CONTINUE WITH THE IDEA OF SNOW SHOWERS TAPERING OFF FROM WEST TO EAST DURING THE EVENING HOURS. WEDNESDAY...RIDGING AT THE SURFACE AND ALOFT BUILD IN WEDNESDAY IN THE WAKE OF TODAY`S SYSTEM. SHOULD BE A NICE DAY WITH TEMPERATURES NEAR OR A BIT COOLER THAN TODAY (THE LATTER BEING ESPECIALLY TRUE THE FARTHER NORTH YOU GO). NEXT SYSTEM TO IMPACT THE REGION ARRIVES WEDNESDAY NIGHT AS A SHORT WAVE TROUGH CROSSES THE NORTHERN PLAINS AND INTO THE WESTERN GREAT LAKES THURSDAY MORNING. THIS WILL INCREASE THE THREAT FOR SNOW FROM WEST TO EAST. SOME QUESTION ABOUT PRECIP TYPE BUT THIS FAR OUT WILL KEEP IT SIMPLE (AND ALL SNOW). MARINE ISSUES...WILL CARRY SMALL CRAFT ADVISORIES TODAY THROUGH THIS EVENING ON THE LAKE MICHIGAN SIDE...AND THIS AFTERNOON AND EVENING ON LAKE HURON. NO HEADLINES ANTICIPATED BEYOND TONIGHT. EARLY EXTENDED PERIODS (THURSDAY THROUGH SATURDAY)...GUIDANCE HAS BEEN PRETTY CONSISTENT IN SHOVING A DRY SLOT ACROSS THE FORECAST AREA THURSDAY...THE IMPLICATION BEING THAT THE THREAT FOR PRECIP SHOULD WIND DOWN DURING THE MORNING WHICH THE CURRENT FORECAST ACCOUNTS FOR. THIS LOOKS LIKE IT CONTINUES INTO THURSDAY NIGHT/ FRIDAY...SO WILL EXTEND THIS DRY PERIOD ACROSS NORTHERN LOWER INTO THOSE PERIODS AS WELL. DRY SATURDAY FORECAST STILL LOOKS FINE AT THIS POINT AS A SOUTHERN BRANCH SHORT WAVE ZIPS ACROSS THE OHIO VALLEY. JPB && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ341-342- 344>346. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LHZ346>349. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 315 PM CDT TUE MAR 11 2008 .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...WARMING TREND EXPECTED INTO FRIDAY ALONG WITH QUIET WEATHER FOR THE SHORT TERM UNTIL THURSDAY NIGHT IN THE WEST. WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS A SHORTWAVE OVER WEST TEXAS THIS AFTERNOON. THIS SHORTWAVE WILL MOVE TO THE EAST SOUTHEAST TONIGHT TRACKING JUST SOUTH OF OUR CWA. THIS WILL BRING A SHORTWAVE TROUGH AXIS ACROSS OUR CWA BUT HAVE LITTLE AFFECT ON OUR SENSIBLE WEATHER. SURFACE HIGH PRESSURE CENTERED OVER THE SOUTHERN PLAINS THIS AFTERNOON WILL SHIFT EAST ACROSS THE GULF COAST AND OFF THE EAST COAST THURSDAY. THIS WILL HELP PROVIDE US WITH A COUPLE OF WARM SPRING-LIKE DAYS. IN THE WAKE OF THE UPPER LEVEL TROUGH AND WITH SURFACE HIGH PRESSURE CENTERED OVER THE MISSISSIPPI GULF COAST WEDNESDAY...DECENT INSOLATION SHOULD LEAD TO AFTERNOON HIGHS REACHING 70 DEGREES AGAIN. AS THE SURFACE HIGH SHIFTS EAST OF CWFA THURSDAY RETURN FLOW WILL HELP TEMPERATURES TOP OUT A FEW DEGREES WARMER IN THE LOWER 70S. OUR AIRMASS WILL STILL BE RATHER DRY THURSDAY WITH BUFR SOUNDINGS SHOWING PWS AT OR BELOW A HALF INCH THURSDAY AFTERNOON. DEEP MOISTURE WILL LIKELY TAKE SOME MORE TIME TO RETURN BUT MODELS SHOW WAA INCREASING THURSDAY NIGHT AHEAD OF A SHORTWAVE AND ASSOCIATED SURFACE LOW OVER TEXAS. BY THE START OF FRIDAY MORNING PWS ARE EXPECTED TO BE BACK ABOVE ONE INCH. ALTHOUGH THE GFS IS A LITTLE FASTER THAN THE NAM IN MODIFYING OUR AIRMASS...SOME FAVORABLE INGREDIENTS FOR MAINLY ELEVATED STRONG TO SEVERE THUNDERSTORMS ARE INDICATED IN THE MODELS OVER THE WESTERN PORTIONS OF OUR CWFA AFTER MIDNIGHT. WL CONTINUE BLURB IN THE HWO. /22/ .LONG TERM...FRIDAY THROUGH TUESDAY...THE EXTENDED STILL LOOKS TO BE ACTIVE AND QUITE INTERESTING. THE MDLS HAVE NOT BACKED OFF FROM THE POSSIBILITY OF SEEING A FEW SERIOUS STORMS FRI AFTN/EVN WITH ANOTHER SYSTEM EARLY TO MID NEXT WEEK. MAIN FOCUS WILL CONCENTRATE ON THE LATE FRI STORM AS NEXT WEEKS SYSTEM STILL HAS QUITE A BIT OF UNCERTAINTIES. THINKING HASN`T CHANGED MUCH ON THE LATE FRI STORM SYSTEM. WARM FRONTAL FEATURE WILL BE SITUATED ALONG THE NRN FRINGES OF THE CWA. LAPSE RATES WILL BE QUITE STEEP DUE TO THE VERY WARM LL TEMPS (H85 OF 14-15C) BEING SHOWN. THESE WARM LL TEMPS WILL ALSO PROVIDE A CAP ACROSS THE CWA BUT IT WILL BE A GOOD DEAL WEAKER IN THE NORTH COMPARED TO THE SOUTH. DURING THE DAY FRI A STRONG MID LEVEL JET CORE WILL PUSH EAST ACROSS THE DESERT SW AND INTO CNTRL TX. THIS INDUCE CYCLOGENESIS AROUND THE TX PANHANDLE AND THE SFC LOW WILL TRACK EAST ALONG THE WARM FRONT THROUGH OK/AR/TN WITH MSLP POSSIBLY DIPPING BELOW 998MB IN THE NW. DEEP MOISTURE IS STILL NOT OVERLY IMPRESSIVE BUT THE LATEST GFS DOES HAVE HIGHER DEWPOINTS NOW FURTHER NORTH(+65 UP TO GLH). THIS IS LIKELY A RESULT OF IT LOSING THE BIG CONVECTIVE FEATURE JUST SOUTH OF LA THIS RUN AND DEVELOPING IT FURTHER TO THE EAST. THIS IS STILL LEADING TO MLCAPE VALUES IN EXCESS OF 2000J/KG AT 0Z FRI. STORMS STILL LOOK LIKE THEY WILL INITIATE TO THE WEST AND NW OF THE CWA FRI AFTN AS THE STRONG MID LEVEL ACCENT PUSHES INTO THAT AREA. LIKE PREVIOUS FCSTER MENTIONED THE STORM MOTION WILL LIKELY BE EAST WITH SOME SLIGHT DEVIATION TO THE ESE/SSE. OVERALL WITH THE STRONG CAP AND LACK OF DEEP MOISTURE STORMS WILL HAVE A HARD TIME GOING AND THEY WILL LIKELY BE FEWER IN NUMBER BUT THAT IS NOT NECESSARILY A GOOD THING. THE STRONG CAP WILL ALLOW US TO BECOME QUITE UNSTABLE(EVIDENT WITH THE +2000J/KG MLCAPE) AND WITH FEWER STORMS THEY WILL BE ABLE TO MAXIMIZE THE ENVIRONMENT. THE SNDG SUGGEST THAT THESE STORMS COULD POSE A RATHER SIGNIFICANT HAIL THREAT AND THE WAY THIS PATTERN IS SETTING UP IT CLOSELY MATCHES AN EVENT ON MAY 3RD 1984 WHICH ALSO PROVIDED SIGNIFICANT HAIL ACROSS THE AREA. ANY STORMS THAT MOVE INTO THE AREA IN THE AFTN AND EARLY EVN WOULD ALSO PROVIDE A DAMAGING WIND AND TORNADO THREAT BUT AFTER WE START TO DECOUPLE THE WIND THREAT WOULD BEGIN TO DIMINISH SOME. IT STILL LOOKS LIKE THE AREA SOUTH OF I 20 WILL BE CAPPED WITH THE CAP INCREASING IN STRENGTH THROUGH THE NIGHT. NORTH OF I 20 THE CAP WILL BE WEAKER AND WITH THE ACCENT FROM THE MID LEVEL JET PUSHING IN THERE SHOULD BE ENOUGH SUPPORT TO GET A FEW STORMS GOING AS EARLY AS FRI AFTN BUT MAINLY INTO THE EVN HRS. ONE MORE THING...JUST LIKE THE PREVIOUS FCSTER MENTIONED IF THE MID LEVEL JET IS DISPLACED FURTHER TO THE NW THEN WE COULD SEE NOTHING. THE ONE THING THAT DOES SEEM LIKELY IS IF WE CAN GET ANY STORMS GOING THEY WILL BE SEVERE AND CONTAIN LARGE HAIL. FOR THE REST OF THE FCST THE MDLS ARE STILL HAVING A DIFFICULT TIME WITH THE TIMING OF THE NEXT SYSTEM. WITH THIS I WILL MAKE NO CHANGES TO THE 00Z GUI AT THIS TIME AND I WILL ATTACH THE PREVIOUS LONG TERM PORTION CONCERNING THESE DAYS. /CAB/ FOR SAT...COLD FRONT WILL ENTER AND MOVE THROUGH THE CWA. I HAVE RAISE LOWS/HIGHS ACROSS THE S HALF BASED ON EXPECTED TIMING OF THE FRONT. MUCH DRIER/STABLE AIR WILL MOVE IN AND KEEP THING DRY THROUGH SUN NIGHT. LATEST GUID LOOKED GOOD HAVE HAVE GENERALLY ACCEPTED. I DID TWEAK UPWARD SOME HIGH TEMPS FOR SUN/MON. THE 3RD SYSTEM IS SHOWING SIGNS OF SLOWING AND COULD IMPACT THE FORECAST AREA ANY TIME BETWEEN MON AFTERNOON AND TUE NIGHT. WHEN EVER IT ARRIVES...IT WILL LIKELY HAVE ENOUGH GOING FOR IT TO BRING A RISK OF STRONG/SVR STORMS. /CME/ && .AVIATION...VFR CONDITIONS WILL PREVAIL THIS EVENING AND LAST THROUGH 08Z WEDNESDAY. A FEW SITES IN THE SOUTH MAY SEE PATCHY FOG DEVELOP AFTER 08Z. VISIBILITIES SHOULD RANGE 3-5SM MAINLY BE BETWEEN 09-13Z. ANY FOG THAT DEVELOPS SHOULD BURN OFF BY 14Z AND VFR CONDITIONS WILL PREVAIL AREAWIDE WEDNESDAY. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 41 71 45 73 / 0 0 0 8 MERIDIAN 36 71 39 74 / 0 0 0 7 VICKSBURG 42 71 46 74 / 0 0 0 7 HATTIESBURG 42 71 40 74 / 0 0 0 8 NATCHEZ 42 71 46 74 / 0 0 0 7 GREENVILLE 43 72 46 73 / 0 0 0 9 GREENWOOD 40 72 46 73 / 0 0 0 10 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM/AVIATION: 22 LONG TERM: CAB/CME ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 331 PM EDT TUE MAR 11 2008 .SYNOPSIS... A WEAK DISTURBANCE IN THE MID LEVELS WILL PRODUCE CLOUDS AND A FEW SPRINKLES OVER THE LOCAL AREA LATE THIS AFTERNOON INTO THIS EVENING. HIGH PRESSURE WILL BUILD IN ON WEDNESDAY. THE HIGH WILL SLIDE OFF THE SOUTHEAST UNITED STATES COAST THURSDAY AND FRIDAY...FOLLOWED BY A COLD FRONT LATE ON SATURDAY. HIGH PRESSURE BUILDS IN SUNDAY AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM TUESDAY...MID TO HIGH LEVEL CLOUDS WILL CONTINUE TO STREAM INTO LOCAL AREA AND INCREASE THROUGH THIS EVENING...ASSOCIATED WITH APPROACHING MID LEVEL SHORTWAVE. THIS SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH THE LOCAL AREA THIS EVENING. WINDS WILL SHIFT BACK AROUND TO THE S-SW THROUGH LATE THIS AFTERNOON..REMAINING MORE ON SHORE AND SLIGHTLY HIGHER ALONG THE COAST. THIS WILL ALLOW AN INCREASE IN MOISTURE TRANSPORT INTO LOCAL AREA AS LATEST RUC/NAM PCP WATER VALUES UP TO NEAR 1 INCH REACHING JUST FAR ENOUGH NORTH INTO THE CAPE FEAR AREA BY 00Z. MOISTURE WILL BE LIMITED BELOW H85...WITH GREATEST RH BETWEEN H70 AND H50 BETWEEN 02-05Z. LATEST SREF DATA SHOWING BEST CHC OF MEASURABLE PCP JUST SOUTH OF CWA AND OFF SHORE BETWEEN 00-06Z THIS EVENING...BUT MOST OF AREA HAS LESS THAN 20% CHC. KEPT ONLY MENTION OF SPRINKLES IN FORECAST MAINLY ALONG THE COAST. BY WED MORNING...SHORTWAVE WILL EXIT THE COAST AND DRY AIR WILL BUILD IN BEHIND IT. SKIES WILL BE CLEARING BY DAYBREAK. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...WEAK HIGH PRESSURE RIDGE REMAINS TO OUR SOUTH THROUGH THE PERIOD...RESULTING IN MILD AND DRY CONDITIONS. THICKNESS PROGS SUPPORT MAX TEMPS IN THE UPPER 60S WED...AND INTO THE LOWER 70S THU. HAVE TRIED TO REFLECT A LARGER SPREAD FOR BEACH TEMPS IN SW FLOW ON THU...BUT WNW LOW-LEVEL FLOW ON WED WILL KEEP ANY SEABREEZE PINNED. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...MOST OF THE ENERGY ALOFT WILL BE IN THE WNR U.S. AT THE START OF THE PD. AND ALTHOUGH GUIDANCE SHOWS REASONABLE AGREEMENT THERE IS STILL CONSIDERABLE DOUBT ABOUT THEIR HAVING THE EVOLUTION OF THE PATTERN CORRECT. BASICALLY THE FLOW SEEMS TO BE TOO ZONAL DOWNSTREAM HERE IN THE EAST AND THAT MORE OF A RIDGE SHOULD BE DEVELOPING. CONVERGENCE BETWEEN THE NRN AND SRN STREAMS SHOULD STILL BE ABLE TO DRIVE A BACKDOOR COLD FRONT THROUGH THE REGION. WITH NEGLIGIBLE FORCING EXPECT A GENERALLY DRY FCST BUT THE PRESENCE OF THE BOUNDARY WILL MAKE ZERO POPS TOUGH TO GO WITH THROUGH SATURDAY. LARGE STORM FORMING OFF THE NE COAST SHOULD BE ABLE TO DRIVE THE FRONT WELL TO THE SOUTH FOR THE REMAINDER OF THE PD. TEMPS FRI AND SAT ABV CLIMO FOR NOW...UNLESS THE BACKDOOR MANAGES TO SLIDE FARTHER SOUTH THAN PROGGED. TEMPS BACK TO CLIMO BEHIND THE MAIN PUSH ON SUNDAY AND INTO MONDAY. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... ONLY AVIATION PLAYER THIS EVENING IS A WEAK SHORT WAVE THAT WILL PROPAGATE NORTHEAST ACROSS THE CWA FROM 23-04Z. OUTSIDE SHOT THAT WE WILL SEE SOME LIGHT PRECIP...BUT MAINLY JUST A MID CLOUD CEILINGS. THIS SHOULD KEEP FOG AT BAY. WINDS WILL SHIFT TO THE NORTHWEST AFTER PASSAGE...WITH SOME GUSTS WEDNESDAY OVER 15KTS. VFR THROUGH THE END OF THE FORECAST PERIOD. POSSIBLE LIGHT FOG THURSDAY AND FRIDAY MORNING...OTHERWISE NO AVIATION CONCERNS THROUGH SATURDAY. && .MARINE... NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 3 PM TUESDAY...LIGHT WINDS WITH SEAS GENERALLY AROUND 2 FT THROUGH THIS EVENING AS GRADIENT REMAINS SLACK. SURFACE TROUGH INDUCED BY AN H5 SHORT WAVE WILL MOVE OFFSHORE TONIGHT...WITH INCREASING WINDS SHIFTING FROM S-SW LATE THIS AFTERNOON TO THE WEST AT AROUND 10 TO 15 KTS BY DAYBREAK WEDNESDAY. SEAS MAY PICK UP AN EXTRA FOOT AS A RESULT...UP TO AROUND 3 FT WELL OFFSHORE AFTER MIDNIGHT. ISOLATED LIGHT SHOWER ACTIVITY MAY ALSO RESULT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...RATHER SLOPPY GRADIENT WITH WEAK HIGH PRESSURE RIDGE TO OUR SOUTH...WILL RESULT IN TRANQUIL MARINE CONDITIONS THRU THE PERIOD. WINDS LESS THAN 15 KT AND SEAS NO MORE THAN 3 FT. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...SWRLY WINDS AHEAD OF A COLD FRONT ON FRIDAY WILL INCREASE SOME AS THE APPROACH OF THE BOUNDARY INCREASES THE GRADIENT. HARD TO TELL IF ANY FLAGS WILL BE REQUIRED ON ACCOUNT OF THE WIND BUT THE COAST-PARALLEL FETCH WILL KEEP ANY OMINOUS SEAS JUST OUTSIDE OF THE FCST AREA. THIS FRONT DROPS IN FROM THE NORTH ON SATURDAY AND MAY STALL RIGHT OVER THE COASTLINE. THIS SHOULD KEEP THE MODERATELY STRONG SWRLY WINDS OVER MOST OF THE WATERS BUT BACKDOOR COLD FRONTS ARE NOTORIOUSLY DIFFICULT TO PREDICT. SHOULD THE BOUNDARY STALL WHERE ANTICIPATED OR FARTHER NORTH THEN THE CURRENT FCST SHOULD HOLD...IF THE BOUNDARY DROPS FARTHER SOUTH THEN A TURN TO NORTHEAST CAN BE EXPECTED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...RAS LONG TERM...MBB AVIATION...DL nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 1249 PM CDT TUE MAR 11 2008 .AVIATION... VFR CONDITIONS EXPECTED FOR THIS TAF PERIOD. UPPER LEVEL LOW DIGGING SEWD WILL TRACK ACROSS WEST CENTRAL TEXAS THIS AFTERNOON...MOISTURE DEPRIVED SYSTEM MAY PRODUCE ISOLATED STORM AND MID LEVEL CLOUDS. SURFACE WINDS WILL BE SOUTHERLY AT 5 TO 15 KTS ACROSS CWFA. USING A BLEND GFS/NAM BROUGHT IN TEMPO GROUP FOR POSSIBLE AM CLOUD DECKS/BKN030 TO BKN050 ACROSS CWFA BETWEEN 11 AND 16Z. && .PREV DISCUSSION... /ISSUED 1047 AM CDT TUE MAR 11 2008/ UPDATE... ADJUSTED DEW POINT TEMPERATURES TO REFLECT CURRENT OBS...THEN INCREASED DAYTIME GRIDS TO REFLECT SLIGHTY HIGHER VALUES. RUC SUPPORTS THESE VALUES INTO THE EARLY EVENING. DID NOT ADJUST DAYTIME TEMPS. SHORT TERM... PREV DISCUSSION... /ISSUED 623 AM CDT TUE MAR 11 2008/ AVIATION... EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT TWENTY FOUR HOURS...EXCEPT AT KSOA AND KBBD WHERE 3-4 SM VISIBILITIES WILL BE POSSIBLE THIS MORNING AS SOME LIGHT FOG DEVELOPS. LIGHT WINDS WILL BECOME MORE SOUTHERLY AT AROUND 10 TO 15 KNOTS THIS AFTERNOON. PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAR 11 2008/ DISCUSSION... CLEAR SKIES AND LIGHT WINDS AS THE SURFACE HIGH SETTLED IN HAS RESULTED IN VISIBILITIES STARTING TO LOWER ACROSS PART OF THE AREA. WILL KEEP THE MENTION OF FOG IN THROUGH THE MORNING HOURS. IN THE UPPER LEVELS...ANOTHER COMPACT...BUT RATHER INTENSE CIRCULATION IS CUTTING SOUTHEAST THROUGH NM. THIS LOW WILL MOVE ACROSS THE REGION TODAY. RUC ANALYSIS SHOWS 500MB TEMPS DOWN TO -20C OR COLDER. THIS MAY BE ENOUGH TO SET OFF A FEW ISOLATED SHOWERS AND/OR THUNDERSTORMS IN THE CONCHO VALLEY AND NORTHERN EDWARDS PLATEAU AS LAPSE RATES INCREASE TO 7.5 TO 8 C/KM. TEMPERATURES WILL INCREASE ACROSS THE AREA TODAY WITH SOUTHERLY FLOW...INCREASING THERMAL RIDGING. THE WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK...AS SOUTHERLY FLOW CONTINUES. AS TEMPERATURES INCREASE...RELATIVE HUMIDITY VALUES WILL DECREASE... AND WILL RESULT IN ELEVATED FIRE DANGER WHICH WILL BE DISCUSSED IN FURTHER DETAIL BELOW. TEMPERATURES WILL WARM INTO THE 80S BY THURSDAY AND FRIDAY. ON FRIDAY...SURFACE WINDS MAY INCREASE SIGNIFICANTLY. AN UPPER LEVEL TROUGH IS FORECAST TO MOVE WEST TO EAST ACROSS THE REGION. AS THIS TAKES PLACE...A SURFACE LOW IS FORECAST TO DEEPEN AND TRANSLATE TO THE EAST OVER OK. THIS WILL INCREASE WESTERLY WINDS...AND WITH 700MB WINDS AT 40 OR 50 KNOTS COMBINED WITH GOOD MIXING...WE MAY SEE WINDS OF 25 TO 35 MPH WITH GUSTS AS HIGH AS 40 MPH. THIS WILL ALSO DRIVE THE DRYLINE EAST THROUGH THE AREA...AND WITH DOWNSLOPING WINDS... DRIER AIR...WE MAY SEE TEMPERATURES REACHING INTO THE UPPER 80S OR EVEN LOWER 90S IN SOME LOCATIONS. CHANCES FOR PRECIP ASSOCIATED WITH THIS FRONT ARE NOT HIGH ENOUGH FOR POPS TO BE INSERTED. A COLD FRONT WILL FOLLOW THIS SYSTEM SATURDAY...BRINGING TEMPERATURES CLOSER TO NORMAL FOR THE WEEKEND. ANOTHER UPPER LEVEL LOW IS EXPECTED TO IMPACT THE AREA DURING THE EARLY PART OF NEXT WEEK...GIVING THE AREA A CHANCE FOR SHOWERS AND THUNDERSTORMS...DEPENDING ON THE AMOUNT OF MOISTURE RETURN AND PATH OF THE UPPER LEVEL SYSTEM. HAVE KEPT THE SLIGHT CHANCE OF PRECIP IN FOR NOW...MAINLY OVER THE EASTERN 2/3 OF THE CWA. FIRE WEATHER... TEMPERATURES WILL WARM DURING THE SECOND HALF OF THE WORK WEEK ACROSS THE AREA AS A THERMAL RIDGE INCREASES OVER THE AREA. FIRE WEATHER DANGERS WILL RISE AS MINIMUM RELATIVE HUMIDITY VALUES FALL. CURRENTLY...THE DAY WITH THE HIGHEST POTENTIAL FOR REACHING CRITICAL FIRE WEATHER VALUES IS FRIDAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA DEEPENING A SURFACE LOW TO THE NORTH OF OUR AREA...AND BRING STRONG MID LEVEL WINDS WITH IT AS WELL. THIS PATTERN IS FAVORABLE FOR PUSHING THE AREA INTO EXTREMELY CRITICAL VALUES CONCERNING FIRE WEATHER. MIXING WILL BE STRONG...AND MAY RESULT IN WIND GUSTS TO 40 MPH OR GREATER OUT OF THE WEST FOR MUCH OF THE AREA. THESE STRONG WEST WINDS WILL ALSO PUSH A DRYLINE THROUGH THE AREA WHICH WILL CAUSE TEMPERATURES TO RISE INTO THE UPPER 80S TO NEAR 90. THIS WILL ALLOW RELATIVE HUMIDITY VALUES TO FALL TO LESS THAN 10 PERCENT ACROSS WESTERN PARTS OF THE CWA. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 67 49 77 53 / 10 0 0 10 SAN ANGELO 67 46 76 53 / 10 0 0 10 JUNCTION 69 46 75 54 / 10 0 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/12 tx