AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1035 PM EST MON FEB 20 2006 .DISCUSSION... ...QUICK UPDATE... UPGRADED ADVY FOR NRN HOUGHTON AND KEWEENAW COUNTIES TO WRNG AFTER RECEIVING SPOTTER REPORT FM LAURIUM OF 6 INCHES ACCUMULATION BTWN 630 PM AND 10 PM. SPOTTER INDICATES SN WAS STILL FALLING HVY AT TIMES WHERE 88D INDICATES 22DBZ AT 13K FT...AND VSBY AT CMX IS AT 1/4SM. CONSIDER POTENTIAL FOR AN ADDITIONAL 2 INCHES OF SNOW IN THIS AREA TO SATISFY WRNG AMT OF 8 INCHES/12 HRS TO BE HI BEFORE EXIT OF DEEP MSTR AND WSHFT TO MORE UNFVRBL NNW SHORTLY AFTR MIDNGT. KC .SHORT TERM... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW POTENT H5 SHRTWV DIVING TOWARD WRN LK SUP FM NRN MN ARND MEAN UPR TROF IN ERN NAMERICA... 12Z-24Z H5 HGT FALLS UP TO 90M AT INL. DESPITE STRENGTH OF SHRTWV APRNT ON RAOBS/WV IMAGERY...SFC LO RATHER ILL DEFINED AT 01Z WITH TROF STRETCHING ACRS CNTRL LK SUP INTO THE MN ARROWHEAD. SO FAR... MOST SN HAS FALLEN OVER THE KEWEENAW CLOSER TO ASSOCIATED LLVL CNVGC. BUT EVEN THOUGH VSBY AT CMX HAS FQTLY BEEN DOWN TO 3/4SM SINCE 21Z...SPOTTER REPORTS FM THE AREA INDICATE LTL MORE THAN AN INCH OF SN HAS FALLEN SO FAR WITH NATURE OF SN RATHER FINE/POWDERY. MID CLD SHIELD HAS OVERSPREAD THE REST OF THE FA...BUT 00Z GRB SDNG SO DRY THERE HAS BEEN LTL IF ANY SN OTHER THAN OVER THE FAR W WHERE SFC COLD FNT IN COMMA TAIL OF SHRTWV IS APRCHG DESPITE VIGOROUS DPVA/DEEP LYR H85-3 QVECTOR CNVGC/H7 UVV. UPSTREAM 00Z INL SDNG IN NLY FLOW BEHIND SHRTWV IS QUITE MOIST AND RELATIVELY UNSTABLE FM THE SFC TO JUST ABV H7...LAPSE RATE JUST ABOUT MOIST ADIABATIC WITH H85/7 TEMPS -15C/-26C. MAIN FCST CONCERNS TNGT ARE SN TRENDS/AMTS AS WELL AS GOING HEADLINES/NEED FOR ANYMORE. LATEST MODEL GUIDANCE SHOW INCOMING SHRTWV TRACKING STEADILY ACRS THE CWA TNGT WITH BEST DEEP LYR QVECTOR CNVGC EXITING ERY SOON AFT 06Z WITH ARRIVAL OF LLVL CAD/NW WIND IN THE WAKE OF SFC LO FCST TO INTENSIFY E OF ANJ OVERNGT. CONSIDERING MOIST/UNSTABLE INL SDNG... HAVE OPTED TO ISSUE LES ADVY FOR ONTONAGON COUNTY WHERE NAM/GFS/RUC ALL SHOW FOCUSED H95 CNVGC WITH FVRBL 320-330 DEGREE FLOW INTO TUE MRNG. LES CHART SUGS A MARGINAL ADVY WITH NO MORE THAN 6"/12 HRS FCST FOR EXPECTED CONDITIONS. WL MAINTAIN GOING ADVY FOR NRN CMX/KEWEENAW COUNTIES UNTIL 11Z AS LLVL CNVGC FCST TO WEAKEN LATE TNGT. CONSIDERING STRENGTH OF INCOMING DPVA/QVECTOR CNGVC...GOING HI CHC/LIKELY POPS ELSEWHERE APPEAR TO BE RSNBL EXCEPT OVER THE SCNTRL CLOSER TO REAL DRY GRB SDNG. BUT QUICK DURATION OF EVENT AND ANTECEDENT DRY AIRMASS IN ABSENCE OF LK MOISTENING WL LIMIT ANY ACCUM TO WELL UNDER ADVY CRITERIA. DESPITE ARRIVAL OF NW FLOW LATE TNGT/EARLY TUE ACRS THE LES BELTS E OF MQT...NAM/GFS/RUC INDICATE UNIMPRESSIVE OR ABSENT LLVL CNVGC IN THESE AREAS. SO NO NEED FOR ADVYS IN THESE AREAS. COORDINATED WITH GRB. KC ...LONG TERM... NAM SHOWS MORE SHORTWAVES ABOUT EVERY 24-30 HOURS OR SO PASSING ACROSS THE REGION WITH MORE ALBERTA CLIPPERS PASSING BY. LAKE EFFECT CONTINUES ON TUE...BUT WINDS DOWN AS THE WINDS TURN TO THE WEST AND SW AHEAD OF THE NEXT CLIPPER FOR TUE NIGHT. NAM THEN BRINGS IN SOME WEAK ISENTROPIC LIFT AND MOISTURE EARLY TUE NIGHT ON I275K-I280K SURFACES BEFORE THE LIFT MOVES OFF TO THE EAST AND 850-500 MB Q-VECTOR CONVERGENCE MOVES IN EARLY TUE NIGHT AND THEN MOVES OUT AFTER MIDNIGHT. NAM BRINGS IN SOME MORE ISENTROPIC LIFT AND MOISTURE EARLY WED NIGHT AS WELL ON I275K-I280K SURFACES BEFORE THE LIFT DISAPPEARS AND THE SAME THING AGAIN HAPPENS WITH THE 850-500 MB Q-VECTOR CONVERGENCE EARLY WED NIGHT. AGAIN...NO MORE THAN A COUPLE OF INCHES OUT OF THESE ALBERTA CLIPPERS AT BEST LOOKS GOOD. THERE WILL ALSO CONTINUE TO BE LAKE EFFECT SNOW BEHIND THESE...BUT THE TRACK CONTINUES TO BE ACROSS THE NORTHERN U.P. OR ACROSS LAKE SUPERIOR...SO LAKE EFFECT IS NOT AT ITS BEST AND MOISTURE IS LIMITED WITH THESE WEAK ALBERTA CLIPPERS. IN THE EXTENDED...ECMWF...UKMET AND GFS ALL SHOW THE 500 MB PATTERN CONSISTS OF A SHORTWAVE OVER THE UPPER GREAT LAKES 00Z SAT AND THIS TROUGH AXIS IS TO THE EAST 00Z SUN. TROUGH AXIS CONTINUES TO THE EAST 00Z MON WITH RIDGING OVER THE ROCKIES AND WESTERN U.S. WILL NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. WILL KEEP SNOW CHANCES IN THE FORECAST THROUGH SUN AND THEN GO DRY ON MON AS ALBERTA CLIPPER SYSTEM MOVES THROUGH ON SAT AND BEHIND IT THE LAKE EFFECT GETS GOING. LOOKS LIKE ON MON THAT THE SFC HIGH PRESSURE SYSTEM IS FAR ENOUGH INTO THE AREA THAT THE LAKE EFFECT SHOULD END. TEMPERATURES LOOK TO BE BELOW NORMAL...BUT NOT AS COLD AS THIS LAST WEEKEND. WENT CLOSE TO ADJENS GUIDANCE FOR LOWS AND HIGHS. MICHELS && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 6 AM EST TUESDAY FOR MIZ001-MIZ003. LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST TUESDAY FOR MIZ002. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 910 PM EST MON FEB 20 2006 .DISCUSSION... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW POTENT H5 SHRTWV DIVING TOWARD WRN LK SUP FM NRN MN ARND MEAN UPR TROF IN ERN NAMERICA... 12Z-24Z H5 HGT FALLS UP TO 90M AT INL. DESPITE STRENGTH OF SHRTWV APRNT ON RAOBS/WV IMAGERY...SFC LO RATHER ILL DEFINED AT 01Z WITH TROF STRETCHING ACRS CNTRL LK SUP INTO THE MN ARROWHEAD. SO FAR... MOST SN HAS FALLEN OVER THE KEWEENAW CLOSER TO ASSOCIATED LLVL CNVGC. BUT EVEN THOUGH VSBY AT CMX HAS FQTLY BEEN DOWN TO 3/4SM SINCE 21Z...SPOTTER REPORTS FM THE AREA INDICATE LTL MORE THAN AN INCH OF SN HAS FALLEN SO FAR WITH NATURE OF SN RATHER FINE/POWDERY. MID CLD SHIELD HAS OVERSPREAD THE REST OF THE FA...BUT 00Z GRB SDNG SO DRY THERE HAS BEEN LTL IF ANY SN OTHER THAN OVER THE FAR W WHERE SFC COLD FNT IN COMMA TAIL OF SHRTWV IS APRCHG DESPITE VIGOROUS DPVA/DEEP LYR H85-3 QVECTOR CNVGC/H7 UVV. UPSTREAM 00Z INL SDNG IN NLY FLOW BEHIND SHRTWV IS QUITE MOIST AND RELATIVELY UNSTABLE FM THE SFC TO JUST ABV H7...LAPSE RATE JUST ABOUT MOIST ADIABATIC WITH H85/7 TEMPS -15C/-26C. MAIN FCST CONCERNS TNGT ARE SN TRENDS/AMTS AS WELL AS GOING HEADLINES/NEED FOR ANYMORE. LATEST MODEL GUIDANCE SHOW INCOMING SHRTWV TRACKING STEADILY ACRS THE CWA TNGT WITH BEST DEEP LYR QVECTOR CNVGC EXITING ERY SOON AFT 06Z WITH ARRIVAL OF LLVL CAD/NW WIND IN THE WAKE OF SFC LO FCST TO INTENSIFY E OF ANJ OVERNGT. CONSIDERING MOIST/UNSTABLE INL SDNG... HAVE OPTED TO ISSUE LES ADVY FOR ONTONAGON COUNTY WHERE NAM/GFS/RUC ALL SHOW FOCUSED H95 CNVGC WITH FVRBL 320-330 DEGREE FLOW INTO TUE MRNG. LES CHART SUGS A MARGINAL ADVY WITH NO MORE THAN 6"/12 HRS FCST FOR EXPECTED CONDITIONS. WL MAINTAIN GOING ADVY FOR NRN CMX/KEWEENAW COUNTIES UNTIL 11Z AS LLVL CNVGC FCST TO WEAKEN LATE TNGT. CONSIDERING STRENGTH OF INCOMING DPVA/QVECTOR CNGVC...GOING HI CHC/LIKELY POPS ELSEWHERE APPEAR TO BE RSNBL EXCEPT OVER THE SCNTRL CLOSER TO REAL DRY GRB SDNG. BUT QUICK DURATION OF EVENT AND ANTECEDENT DRY AIRMASS IN ABSENCE OF LK MOISTENING WL LIMIT ANY ACCUM TO WELL UNDER ADVY CRITERIA. DESPITE ARRIVAL OF NW FLOW LATE TNGT/EARLY TUE ACRS THE LES BELTS E OF MQT...NAM/GFS/RUC INDICATE UNIMPRESSIVE OR ABSENT LLVL CNVGC IN THESE AREAS. SO NO NEED FOR ADVYS IN THESE AREAS. COORDINATED WITH GRB. KC ...LONG TERM... NAM SHOWS MORE SHORTWAVES ABOUT EVERY 24-30 HOURS OR SO PASSING ACROSS THE REGION WITH MORE ALBERTA CLIPPERS PASSING BY. LAKE EFFECT CONTINUES ON TUE...BUT WINDS DOWN AS THE WINDS TURN TO THE WEST AND SW AHEAD OF THE NEXT CLIPPER FOR TUE NIGHT. NAM THEN BRINGS IN SOME WEAK ISENTROPIC LIFT AND MOISTURE EARLY TUE NIGHT ON I275K-I280K SURFACES BEFORE THE LIFT MOVES OFF TO THE EAST AND 850-500 MB Q-VECTOR CONVERGENCE MOVES IN EARLY TUE NIGHT AND THEN MOVES OUT AFTER MIDNIGHT. NAM BRINGS IN SOME MORE ISENTROPIC LIFT AND MOISTURE EARLY WED NIGHT AS WELL ON I275K-I280K SURFACES BEFORE THE LIFT DISAPPEARS AND THE SAME THING AGAIN HAPPENS WITH THE 850-500 MB Q-VECTOR CONVERGENCE EARLY WED NIGHT. AGAIN...NO MORE THAN A COUPLE OF INCHES OUT OF THESE ALBERTA CLIPPERS AT BEST LOOKS GOOD. THERE WILL ALSO CONTINUE TO BE LAKE EFFECT SNOW BEHIND THESE...BUT THE TRACK CONTINUES TO BE ACROSS THE NORTHERN U.P. OR ACROSS LAKE SUPERIOR...SO LAKE EFFECT IS NOT AT ITS BEST AND MOISTURE IS LIMITED WITH THESE WEAK ALBERTA CLIPPERS. IN THE EXTENDED...ECMWF...UKMET AND GFS ALL SHOW THE 500 MB PATTERN CONSISTS OF A SHORTWAVE OVER THE UPPER GREAT LAKES 00Z SAT AND THIS TROUGH AXIS IS TO THE EAST 00Z SUN. TROUGH AXIS CONTINUES TO THE EAST 00Z MON WITH RIDGING OVER THE ROCKIES AND WESTERN U.S. WILL NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. WILL KEEP SNOW CHANCES IN THE FORECAST THROUGH SUN AND THEN GO DRY ON MON AS ALBERTA CLIPPER SYSTEM MOVES THROUGH ON SAT AND BEHIND IT THE LAKE EFFECT GETS GOING. LOOKS LIKE ON MON THAT THE SFC HIGH PRESSURE SYSTEM IS FAR ENOUGH INTO THE AREA THAT THE LAKE EFFECT SHOULD END. TEMPERATURES LOOK TO BE BELOW NORMAL...BUT NOT AS COLD AS THIS LAST WEEKEND. WENT CLOSE TO ADJENS GUIDANCE FOR LOWS AND HIGHS. MICHELS && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST TUESDAY FOR MIZ001-MIZ003. LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST TUESDAY FOR MIZ002. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 141 PM CST MON FEB 20 2006 .DISCUSSION...TONIGHT THROUGH THURSDAY CLDS AND A FEW VRY LGT SNOW SHWRS MAKING THEIR WAY SEWRD INTO THE FA...AS VORT MAX IN ERN NODAK /EVIDENT IN WV IMAGERY/ SWINGS TOWARD MN AND WI THIS AFTN. LEADING EDGE OF HI/MID CLD DECK STRETCHES FROM ROUGHLY WHEATON TO LITTLE FALLS TO ASHLAND WI. LOCATION OF THE FLURRIES ACRS BOTH THE FGF AND DLH FA ARE RESOLVED WELL IN THE 280K ISENTROPIC ANALYSIS FROM THE 15Z RUC. ASSOC SFC LO SITTING ALNG THE INTL BRDR IN N CNTRL MN AT MIDDAY...WHICH IS RESPONSIBLE FOR THE BREEZY SW WINDS TDA. TEMPS HAVE AGAIN MADE A BIG JUMP THIS AFTN UNDER THE PREVAILING SWLY LO LVL FLO AND SUNNY SKIES...WITH 19Z SFC OBS SHOWING MID AND UPR 20S ACRS THE MAJORITY OF THE FA. WIND SHIFT LINE TRAILING FROM THE SFC LO STRETCHES FROM THE CNTR OF THE SFC LO /NEAR INL/ SWWRD TO AROUND PIR. CURRENT MOVEMENT OF ECHOES ON THE LOCAL 88D MOSAIC TAKE THE LIGHTER RETURNS ACRS THE FAR NRN PORTION OF THE FA...ROUGHLY N OF A LINE FROM AXN TO JMR. FOLLOWING THE NEAR SATURATION ON THE 280K SFC FROM THE 15Z RUC...THE LGT PCPN SHUD MOVE INTO PORTIONS OF POLK...BARRON...AND RUSK COUNTIES THIS EVE. HAVE INSERTED SOME VRY SMALL POPS IN THESE AREAS ALTHO THE PCPN SHUD BE LGT. ATTENTION THEN TURNS TO SYSTEM DROPPING OUT OF CANADA ON TUE. BOTH THE NAM AND THE GFS HAVE TRENDED A LITTLE STRONGER AND A LITTLE FARTHER S OVER THE PAST FEW RUNS...ALTHO THE BULK OF THE PCPN SHUD STILL AFFECT THE NRN PART OF MN. STRONGEST MID LVL WAA WILL MOVE INTO THE NWRN PORTION OF THE FA BTWN 12 AND 15Z ON TUE MRNG AND MOVE EWRD...CLEARING THE WI COUNTIES BEFORE MIDNGT TUE NGT. HAVE CONFINED THE POPS TO THE NRN HALF OF THE FA...WITH THE HIGHEST POPS ACRS THE NRN QUARTER. NEXT CLIPPER SYSTEM WILL APPROACH A DAY LATER...ON WED. ATTM...THIS SYSTEM IS FARTHER N THAN ITS PREDECESSOR...WITH THE FORCING MOVING ACRS THE NRN THIRD OF MN ON WED AFTN AND WED NGT. HAVE KEPT SLGT CHC POPS ACRS THE NRN FA. SFC HIGH WILL SLIDE INTO THE AREA ON THU...WHICH WILL BRING A REPRIEVE FROM THE SMALL SNOW CHCS. TEMP WISE...THINGS SHUD BE WARM THRU THE END OF THE WEEK...WITH H8 TEMPS IN THE SINGLE DIGITS BELOW ZERO FOR A GOOD PORTION OF THE WEEK. LONGER TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT FAST ZONAL UPPER AIR FLOW FROM THE GULF OF ALASKA INTO THE GREAT LAKES...WILL PERSIST INTO FRIDAY. THE LAST IN A SERIES OF SHORT WAVE TROUGHS WILL MOVE OVER THE UPPER MIDWEST ON FRIDAY AS PER THE LATEST LONG RANGE MODELS OFF BOTH THE GFS ENSEMBLE AND ECMWF. SHORTWAVE TROUGH/AND APPARENT COLD FRONT SHOULD HELP WRING OUT SOME LIGHT SNOW OR FLURRIES OVER THE FORECAST AREA ON FRIDAY. ARCTIC CDFNT PUSHES SOUTH INTO THE SOUTHERN PLAINS OVER THE WEEKEND. THUS ANOTHER BOUT OF SUBZERO TEMPERATURES OVER THE THE WEEKEND. LONGWAVE RIDGE BEGINS TO BUILD OVER THE UPPER MIDWEST AND SLIDE EAST OVER THE NATIONS MIDSECTION BY MONDAY EVENING. EXPECT A DOWNWARD SPIRAL TEMPERATURE TREND FOR THE BULK OF THE PERIOD THEN TEMPERATURES SLOWLY MODERATE BACK INTO THE 20S BY MONDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT/JVM mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 830 PM EST MON FEB 20 2006 .SHORT TERM...BULK OF THE PCPN HAS PUSHED OFFSHORE AND CLOUDS ARE CONFINED MAINLY TO SRN HALF OF THE CWA THIS EVNG. WATER VAPOR IMAGERY DOES SHOW A MID LVL DISTURBANCE SLIDING OFFSHORE BUT DO EXPECT INCREASING CLOUDS LATER TONIGHT AS NEXT DISTURBANCE MOVES INTO WRN CWA LATE TONIGHT IN FAST ZONAL FLOW ALOFT. ENHANCED CLOUDS CURRENTLY OVER TN WILL MOVE INTO THE AREA AND SOME LIGHT PCPN SHOULD DEVELOP WELL AFTER MIDNIGHT. STILL WILL SCALE BACK POPS SOMEWHAT THIS EVNG AS BOTH LATEST RUC AND NAM INDICATE LESS QPF OVERNIGHT. TEMPS HAVE FALLEN ACROSS NRN CWA BUT WITH INCREASING CLOUDS LATER DO NOT EXPECT THEM TO FALL MUCH MORE. WILL HAVE UPDATED ZONES IN A BIT. && .AVIATION...MAINLY VFR OVER THE RGN NOW BUT DO EXPECT SOME LOWER CIGS OF THE MVFR VARIETY LATE TONIGHT AS MSTR INCREASES ACROSS THE RGN. IFR NOT LIKELY AT THIS TIME AS ANY PCPN SHOULD BE LIGHT AND WILL BE SUFFICIENT TO LOWER CIGS MORE THAN INTERMITTENTLY. && .MARINE...BUOY 41025 STILL INDICATING 2 TO 3 FT THIS EVNG. SFC WINDS ARE LIGHT AND VARIABLE ACROSS THE COASTAL WATERS AND SOUNDS. THIS IS IN LINE WITH SFC RIDGE AXIS DRIFTING OFFSHORE. WINDS SHOULD BECOME MORE WEST TO SW OVERNIGHT AS THE RIDGE SLIDES FARTHER EAST BUT WINDS WILL REMAIN GENERALLY 10 KT OR LESS MOST AREAS WITH SEAS NO MORE THAN 3 FT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ MLF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 845 PM CST MON FEB 20 2006 FORECAST CHALLENGE CONCERNS CLOUD TRENDS/TEMPERATURES AND SNOW CHANCES. SURFACE RIDGE AXIS TO SHIFT EAST ACROSS FA TONIGHT. SKIES HAVE CLEARED UNDER RIDGE IN ZONE OF Q-VECTOR DIVERGENCE. NEXT IN SERIES OF SHORTWAVES OVER SASK/AB TO AFFECT FA MAINLY NEXT PERIOD(TUESDAY) CONSIDERING SNOWFALL. MAIN AFFECTS WITH FEATURE WILL BE INCREASING WARM ADVECTION AND ASSOCIATED CLOUD COVER SPREADING FROM WEST TO EAST LATE TONIGHT. CLOUDS MAY NOT REACH EASTERN AREAS BASED ON RUC TIMING SO WILL SEE COLDEST READINGS THIS AREA. TEMPERATURES APPROACHING MINIMUM VALUES ACROSS FAR NW SO WILL NEED TO MAKE SOME SLIGHT ADJUSTMENTS THERE UNTIL CLOUDS ROLL IN. REMAINDER OF FORECAST LOOKING OK WITH ONLY MINOR ADJUSTMENTS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 922 PM EST MON FEB 20 2006 .SHORT TERM (REST OF TONIGHT)... WEAK WAVES IN THE ZONAL FLOW ALOFT AND RIGHT ENTRANCE REGION OF UPPER JET PRODUCING ENUF LIFT TO SQUEEZE OUT SOME VERY LIGHT PRECIP ECHOES OVER RADARS FROM KGSP WWD. THIS AREA OF PRECIP WILL CONTINUE THRU ABOUT 06Z...THEN QUICKLY EXIT THE AREA AS WAVE MOVES EAST. 00Z H85 CHART IS VERY MOIST SO SOME OF THIS PRECIP WILL REACH THE GROUND. HOWEVER ANY AMOUNTS WILL BE VERY LIGHT. HAVE BUMPED EARLY POP UP A LITTLE...BUT KEPT FCST PRECIP FREE AFTER 06Z. WINDS AND CLOUDS HAVE KEPT TEMPS AND DEW POINTS QUITE A BIT HIGHER THAN PREV FCST. WITH THE CLOUDS AND SOME WIND HOLDING ON THRU MOST OF THE NIGHT...HAVE RAISED LOWS A LITTLE ACROSS THE NORTH AND A LITTLE MORE ACROSS THE SOUTH. ONLY MINOR CHANGES TO THE OTHER FIELDS OVERNIGHT. && .PREVIOUS DISCUSSION... (ISSUED 246 PM EST MON FEB 20 2006) SHORT TERM (TONIGHT THROUGH TUESDAY)... SHORT RANGE MODELS INDICATE THAT MOISTURE WILL CONTINUE TO DECREASE OVERNIGHT AND TUESDAY FROM THE TOP DOWN. THIS SHOULD RESULT IN THE GREATEST COVERAGE OF CLOUDS OVER THE MTNS. PRECIPITATION CHC APPEARS SMALL CONSIDERING UPSTREAM RADAR TRENDS AND NAM AND RUC QPF FIELDS. WILL LOWER POPS TO SCHC THROUGH 6Z...OTHERWISE...WILL KEEP POPS AT OR BELOW 10%. BY SUNRISE...PATCHY FOG MAY DEVELOP MAINLY ACROSS THE UPPER SAVANNAH RIVER VALLEY AND THE UPSTATE. MODEL FIELDS INDICATE THAT SOME ISO DENSE FOG MAY ALSO DEVELOP...WILL PAINT AS PATCHY FOG LATE TONIGHT. TUESDAY...WEAK LEE TROF WILL RESULT IN LIGHT AND VARIABLE WINDS. WEAK WAA AND POSSIBLY MORE SUN WILL YIELD TEMPS A CATE HIGHER THAN TODAY/S. WILL USE A BLEND OF THE MOS SOLUTIONS FOR TEMPS AND DWPTS. LONG TERM (TUESDAY NIGHT THROUGH MONDAY)... ZONAL FLOW ALOFT WILL CONTINUE WED INTO THE WEEKEND WITH WEAK...FAST MOVING SHORTWAVES TRANSLATING THROUGH THE FLOW. MODEL RUN TO RUN CONSISTENCY REMAINS A PROBLEM...WITH TIMING AND STRENGTH OF THESE WEAK SYSTEMS. BRIEF WARMUP CONTINUES WED AS HIGH PRES MOVES E AND SW FLOW DEVELOPS. THIS WILL ALSO BRING INCREASED MOISTURE TO THE REGION WITH CHANCE POPS WED AND WED NIGHT. LOOKING AT THICKNESS AND FCST SOUNDINGS THERE IS THE CHANCE OF A RAIN-SNOW MIX EARLY WED FOR MTNS...THEN AGAIN WED NIGHT...WITH CHANCE SNOW ABOVE 3K FT. EXPECT RAIN DURG DAY. HIGH PRESSURE BUILDS IN THU INTO FRI WITH CHANCE POP FRI NIGHT INTO SAT WITH A WINTRY MIX PSBL...MAINLY OVER MTNS. COOL HIGH PRESSURE IS FORECAST TO BUILD IN SUN-MON. AVIATION... BAND SHRA WILL REMAIN SOUTH OF THE WESTERN CAROLINAS...EXCEPT KAND MAY SEE A PERIOD OR TWO OF SHRA THIS AFTERNOON. LLVL MOISTURE MAY LINGER IN THE VICINITY OF KAND THROUGH THE TAF PERIOD...WITH A SMALL WINDOW OF VFR CONDITIONS THIS AFTERNOON. OTHERWISE...TERMINALS THIS EVENING SHOULD REMAIN VFR WITH WINDS LESS THAN 10 KTS. KGSP...KGMU...KAND...AND KCLT SHOULD DEVELOP IFR TO LIFR FOG AND STRATUS TONIGHT. FORECAST SOUNDINGS AND NAM COND PRES DEF INDICATE THE THE UPPER SAVANNAH RIVER VALLEY AND CAROLINA PIEDMONT MAY SEE FOG DEVELOP AS TEMPS APPROACH XOVR TEMPS. MOS SUPPORTS CONDITIONS FALLING BELOW MVFR...HOWEVER...MOS DOES NOT GO AS LOW FOR VIS. KHKY AND KAVL SHOULD REMAIN DISCONNECTED FROM THE GREATER LLVL MOISTURE...HOWEVER...MVFR CEILINGS MAY IMPACT THE TERMINALS. AFTER MORNING MIXING...AROUND 15Z...VFR SHOULD RETURN WITH LIGHT WINDS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM...RWH sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 246 PM EST MON FEB 20 2006 .SHORT TERM (TONIGHT THROUGH TUESDAY)... SHORT RANGE MODELS INDICATE THAT MOISTURE WILL CONTINUE TO DECREASE OVERNIGHT AND TUESDAY FROM THE TOP DOWN. THIS SHOULD RESULT IN THE GREATEST COVERAGE OF CLOUDS OVER THE MTNS. PRECIPITATION CHC APPEARS SMALL CONSIDERING UPSTREAM RADAR TRENDS AND NAM AND RUC QPF FIELDS. WILL LOWER POPS TO SCHC THROUGH 6Z...OTHERWISE...WILL KEEP POPS AT OR BELOW 10%. BY SUNRISE...PATCHY FOG MAY DEVELOP MAINLY ACROSS THE UPPER SAVANNAH RIVER VALLEY AND THE UPSTATE. MODEL FIELDS INDICATE THAT SOME ISO DENSE FOG MAY ALSO DEVELOP...WILL PAINT AS PATCHY FOG LATE TONIGHT. TUESDAY...WEAK LEE TROF WILL RESULT IN LIGHT AND VARIABLE WINDS. WEAK WAA AND POSSIBLY MORE SUN WILL YIELD TEMPS A CATE HIGHER THAN TODAY/S. WILL USE A BLEND OF THE MOS SOLUTIONS FOR TEMPS AND DWPTS. && .LONG TERM (TUESDAY NIGHT THROUGH MONDAY)... ZONAL FLOW ALOFT WILL CONTINUE WED INTO THE WEEKEND WITH WEAK...FAST MOVING SHORTWAVES TRANSLATING THROUGH THE FLOW. MODEL RUN TO RUN CONSISTENCY REMAINS A PROBLEM...WITH TIMING AND STRENGTH OF THESE WEAK SYSTEMS. BRIEF WARMUP CONTINUES WED AS HIGH PRES MOVES E AND SW FLOW DEVELOPS. THIS WILL ALSO BRING INCREASED MOISTURE TO THE REGION WITH CHANCE POPS WED AND WED NIGHT. LOOKING AT THICKNESS AND FCST SOUNDINGS THERE IS THE CHANCE OF A RAIN-SNOW MIX EARLY WED FOR MTNS...THEN AGAIN WED NIGHT...WITH CHANCE SNOW ABOVE 3K FT. EXPECT RAIN DURG DAY. HIGH PRESSURE BUILDS IN THU INTO FRI WITH CHANCE POP FRI NIGHT INTO SAT WITH A WINTRY MIX PSBL...MAINLY OVER MTNS. COOL HIGH PRESSURE IS FORECAST TO BUILD IN SUN-MON. && .AVIATION... BAND SHRA WILL REMAIN SOUTH OF THE WESTERN CAROLINAS...EXCEPT KAND MAY SEE A PERIOD OR TWO OF SHRA THIS AFTERNOON. LLVL MOISTURE MAY LINGER IN THE VICINITY OF KAND THROUGH THE TAF PERIOD...WITH A SMALL WINDOW OF VFR CONDITIONS THIS AFTERNOON. OTHERWISE...TERMINALS THIS EVENING SHOULD REMAIN VFR WITH WINDS LESS THAN 10 KTS. KGSP...KGMU...KAND...AND KCLT SHOULD DEVELOP IFR TO LIFR FOG AND STRATUS TONIGHT. FORECAST SOUNDINGS AND NAM COND PRES DEF INDICATE THE THE UPPER SAVANNAH RIVER VALLEY AND CAROLINA PIEDMONT MAY SEE FOG DEVELOP AS TEMPS APPROACH XOVR TEMPS. MOS SUPPORTS CONDITIONS FALLING BELOW MVFR...HOWEVER...MOS DOES NOT GO AS LOW FOR VIS. KHKY AND KAVL SHOULD REMAIN DISCONNECTED FROM THE GREATER LLVL MOISTURE...HOWEVER...MVFR CEILINGS MAY IMPACT THE TERMINALS. AFTER MORNING MIXING...AROUND 15Z...VFR SHOULD RETURN WITH LIGHT WINDS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM...NED LONG TERM...RB AVIATION...NED sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 950 AM EST MON FEB 20 2006 .SHORT TERM /TODAY THROUGH TONIGHT/...WV IMAGERY SHOWS A LARGE STREAM OF MOISTURE FROM NRN MEXICO/TX REACHING THE SE CONUS. RADARS INDICATE A LARGE SWATH OF PRECIP FROM LA ACRS THE GULF COAST STATES TO THE CAROLINAS...SOME OF WHICH IS IMPACTING FAR NRN PORTIONS OF THE CWFA. RUC/M-ETA INDICATE MODEST ISENTROPIC LIFT IMPACTING MAINLY ALONG AND N OF A LINE FROM KAHN-KWYN-KNBC WHICH INVOF THE DEEPEST MOISTURE...AND DEVELOPING LOW PRES CNTR ABOUT 50 NM OFFSHORE OF KCHS WILL HELP THE PVA. ALTHOUGH ANY PRECIP FALLING WILL BE LIGHT...DO NOT FEEL COMFORTABLE LEAVING POPS IN THE SLGT CHC CATEGORY SO WILL INCRS TO THE CHC CATEGORY FOR THE NRN HALF OF THE CWFA WHILE THE SRN HALF CAN REMAIN IN THE SLGT CHC CATEGORY. IN ADDITION...WITH SUCH A LARGE AREA OF DEEP MOISTURE IN PLACE...WILL INCRS CLOUD COVER IN THE GRIDS TO OVC. ALONG THE LINES OF THE PERSISTENT DEEP MOISTURE PRODUCING LOW CLOUD DECKS TDA...TEMPS WILL HAVE A DIFFICULT TIME RISING MUCH FURTHER THAN THE LOW TO MID 40S SEEN IN THE CURRENT OBS...ESP IN SC. 06Z MOS GUIDANCE CAME IN WITH MAX TEMPS LOWER THAN THE 00Z GUIDANCE... AND CURRENT TEMPS ARE BELOW THE 06Z MOS GUIDANCE TEMP CURVES. WILL DROP MAX TEMPS TO THE UPR 40S IN NRN PORTIONS OF THE CWFA THEN TRANSITION TO ARND 50 ARND THE SAVANNAH RIVER TO LWR 50S IN GA. GIVEN PERSISTENT MOISTURE FLOW AND POCKETS OF LIFT THRU THIS EVE AND TNGT...HAVE RAISED POPS INTO THE CHC CATEGORY. HAVE ALSO SLIGHTLY DROPPED MIN TEMPS TNGT GIVEN LOWER MAX TEMPS TDA...ESP IN SC. && .MARINE...ONGOING FCST HAS WX ELEMENTS WELL HANDLED. SABSOON TWRS AND 41004/41008 HAVE REPORTED WAVE HEIGHTS NO HIGHER THAN 5 FT AND THESE HEIGHTS ARE EXPECTED TO REMAIN STEADY THRU MIDDAY THEN DROP OFF BY LATE DAY AS THE LOW PRES CNTR FORMING IN THE COASTAL WATERS PUSHES OFF INTO THE ATLC. WILL RUN WITH A SCEC HEADLINE IN THE OUTER GA WATERS BUT SHOULD NOT NEED ANY HEADLINES GOING INTO TNGT. ALL WATERS WITHIN 20 NM OF SHORE WILL REMAIN BELOW SCA CRITERIA TDA. WIND DIRECTIONS MAY BE A BIT TROUBLESOME WITH THE LOW PRES AREA OFFSHORE SO WILL MAINTAIN VRBL WORDING WITH SPEEDS AOB 10 KT. && .AVIATION...CIGS WILL BE AT LEAST AS LOW AS MVFR THRU THE FCST PERIOD...BUT THERE IS THE POTENTIAL FOR EVEN IFR CIGS AS THE FCST PROGRESSES. LIGHT NNE WINDS THIS MORNING TO BECOME SW DURING THE MID-LATE AFTN AND CONTINUING TONIGHT. RAIN CHANCES NOT HIGH ENOUGH /ABOUT 20-30 PERCENT/ TO WARRANT INCLUSION IN THE TAFS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ JPC sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 942 AM EST MON FEB 20 2006 .SHORT TERM (REST OF TODAY)... 88D SHOWS A BAND OF LIGHT RAIN MOVING EWD ACROSS THE AREA THIS MORNING. LOOKING UPSTREAM ACROSS GA/AL...APPEARS TO BE SOME ADDITIONAL LIGHT RAIN AS WELL. SATELLITE SHOWS LOTS OF CLODS MOVING ACROSS THE SOUTHEAST. LOOKING AT 12Z NAM...IT DID SHOW WEAK ISENTROPIC LIFT ACROSS THE AREA THIS MORNING WITH NEARLY NEUTRAL MOTION DURING THE AFTERNOON. THINK LIGHT RAIN WILL CONTINUE THROUGH THE MORNING WITH IT BECOMING MORE WIDELY SCATTERED BY AFTERNOON. WILL BUMP UP POPS CLOSER TO 50 PERCENT FOR THE FIRST PORTION OF THE DAY THEN CONTINUE WITH LOWER POPS FOR THE AFTERNOON. SKIES SHOULD REMAIN CLOUDY. TEMPERATURES STILL LOOK ON TRACK FOR THE AFTERNOON. && .PREVIOUS DISCUSSION... (ISSUED 220 AM EST MON FEB 20 2006) SHORT TERM (TODAY THROUGH WEDNESDAY)... THE MAIN SHORT-TERM FORECAST PROBLEM IS PRECIPITATION TYPE IN THE NORTH PART OF THE FORECAST AREA. THE NAM AND GFS TIME-HEIGHTS INDICATE SLEET MAY OCCUR. THE LATEST RUC TIME-HEIGHTS SHOW SLEET OR FREEZING RAIN MAY OCCUR. THE LATEST MSAS WET BULB TEMPERATURES ARE CLOSE TO FREEZING IN THE EXTREME NORTH PART. HOWEVER...ALL MODELS SHOW LITTLE LIFT AND INDICATE ANY PRECIPITATION WILL BE LIGHT. H85 WARM ADVECTION APPEARS VERY WEAK WITH LITTLE UPPER-LEVEL SUPPORT IN THE ZONAL FLOW. THE THREAT OF FREEZING RAIN APPEARS VERY LOW BECAUSE OF LIGHT PRECIPITATION LIMITING EVAPORATIVE COOLING AND JUST MARGINAL WET BULB ZERO TEMPERATURES. IF FROZEN PRECIPITATION DOES OCCUR SLEET APPEARS MOST LIKELY. THIS SHOULD NOT BE SIGNIFICANT BECAUSE OF THE EXPECTED LIGHT AMOUNT AND RELATIVELY WARM GROUND TEMPERATURES. ENOUGH WARMING FOR ALL RAIN SHOULD HAVE OCCURRED BY THIS AFTERNOON. ALL MODEL TIME-HEIGHTS AND THE LATEST MSAS ANALYSIS INDICATE PLAN RAIN FOR THE COLUMBIA AREA SOUTHWARD. THE MODEL POPS SHOW A LARGE SPREAD TODAY. THE LOW GFS MOS POP HAS BEEN CONSISTENT AND BASED ON EXPECTED WEAK LIFT AND CURRENT RADAR TRENDS IT APPEARS BEST. EXPECT LITTLE CHANGE FOR TONIGHT AND TUESDAY WITH JUST WEAK SUPPORT FOR RAIN. THE MODEL POPS ARE CLOSE AND PLAN TO FOLLOW. THE GFS AND NAM ARE CONSISTENT IS SHOWING STRONGER ISENTROPIC LIFT DEVELOPING TUESDAY NIGHT AND CONTINUING INTO EARLY WEDNESDAY. THE MET AND MAV POPS ARE CLOSE AND PLAN TO FOLLOW. PLAN TO USE THE GUIDANCE CONSENSUS LOW TEMPERATURES THROUGH THE PERIOD...AND USE THE COOLER GUIDANCE FOR THE HIGH TEMPERATURES BECAUSE OF EXPECTED CLOUDINESS. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)... CONFIDENCE IS LOW DURING THE EXTENDED PERIOD WITH CONTINUED DIFFICULT TO TIME SHORTWAVE TROUGHS IN THE FAST ZONAL FLOW. THE LATEST GFS LOOKS WET FOR SATURDAY WHICH IS A CHANGE FROM PREVIOUS RUNS. WILL WAIT FOR MORE CONSISTENCY BEFORE MAKING A CHANGE TO THE FORECAST. AVIATION... HIGH PRESSURE WILL WEAKEN TODAY AS MINOR UPPER LEVEL DISTURBANCES MOVE ACROSS THE AREA. GENERALLY BKN-OVC CIGS AROUND 4000 FT FOR MUCH OF THE DAY. A FEW SPRINKLES OR ICE PELLETS ARE POSSIBLE NORTH OF CAE BEFORE 14Z THIS MORNING. SURFACE WINDS WILL BE LIGHT AND VARIABLE THIS MORNING BECOMING LIGHT FROM THE S AND SW DURING THE AFTERNOON. FIRE WEATHER... SMOKE MANAGEMENT COORDINATION TODAY SW 13 2000 TUESDAY SW 9 3000 && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 77 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 810 PM CST MON FEB 20 2006 .DISCUSSION...RUC 200MB WIND/WIND SPEED ANALYSIS INDICATED SUBTROPICAL JET MOVING ACROSS THE EASTERN UNITED STATES WITH A NEARLY ZONAL FLOW ACROSS THE SOUTHERN TIER OF THE COUNTRY EXCEPT OVER CALIFORNIA WHERE A 500MB LOW CONTINUES TO DRIFT SLOWLY SOUTHWARD. SHALLOW COLD AIR ACROSS THE SOUTHEAST UNITED STATES HAS MOVED AWAY FROM WEST TX THIS EVENING AS WARM AIR ADVECTION HAS DEVELOPED ACROSS WEST TX. MSAS SURFACE ANALYSIS INDICATED A STATIONARY BOUNDARY WAS DRAPED ACROSS A SURFACE LOW OFFSHORE THE LOWER TX COAST AND COASTAL BEND. ONSHORE FLOW EXPECTED TO DEVELOP TONIGHT WITH LOW PRESSURE OVER WEST TX AND HIGH PRESSURE OVER THE SOUTHEAST UNITED STATES. FOG LIKELY TO DEVELOP ACROSS THE LOWER RIO GRANDE VALLEY TONIGHT WITH NEARLY SATURATED AIR BELOW 850MB AS INDICATED ON 00Z KBRO SOUNDING. WILL UPDATE ZONES/GRIDS TO ADJUST CLOUD COVER TONIGHT. WARMER TEMPERATURES EXPECTED THE NEXT COUPLE OF DAYS BUT STILL QUITE A BIT OF UNCERTAINTY TOWARDS THE END OF THE WEEK AS LATEST GFS RUN PROGS A COLD FRONT MOVING INTO SOUTH TX THURSDAY WITH HIGH PRESSURE OVER THE SOUTHERN PLAINS WEDNESDAY MOVING EASTWARD. ANOTHER FRONT IS EXPECTED TO MOVE INTO SOUTH TX SATURDAY WITH HIGH PRESSURE SURGING ACROSS THE CENTRAL UNITED STATES. COOL AND CLOUDY CONDITIONS LIKELY TO RETURN FOR THE END OF THE WEEKEND WITH A SLIGHT CHANCE OF RAIN. && .MARINE...FAIRLY BENIGN CONDITIONS WILL PREVAIL ACROSS THE OFFSHORE WATERS INTO THE OVERNIGHT PERIOD AS A LIGHT PGF DOMINATES THE REGION. THIS LIGHT WIND REGIME WILL LIKELY ALLOW SOME AREAS OF MARINE FOG TO FORM OUT OVER THE BAY AND GULF WATERS LATER TONIGHT AND WILL INCLUDE A MENTION OF THIS IN THE NEXT CWF UPDATE. OTHERWISE...WILL MAINTAIN THE MARINE WINDS SHIFTING AROUND TO THE SOUTHEAST AND INCREASING ON TUESDAY AS THE NEXT SURFACE LOW SPINS UP OVER THE SOUTH CENTRAL PLAINS. OVERALL CWF WORDING LOOKS OK WITH NO OTHER MAJOR CHANGES NEEDED. && .AVIATION...CEILINGS AND VSBYS ARE BEGIN TO LOWER AROUND THE LOWER RGV AIRPORTS THIS EVENING AS THE LIGHT SURFACE WINDS COMBINE WITH THE NARROWING TEMPERATURE AND DEWPOINT SPREADS AROUND THE REGION. THIS TREND WILL CONTINUE INTO THE OVERNIGHT PERIOD WITH CONDITIONS IMPROVING AFTER SUNRISE TUESDAY AS THE SOUTHEASTERLY GRADIENT BEGINS TO INCREASE ONCE AGAIN. OVERALL TAF WORDING LOOKS ON TRACK WITH NO MAJOR CHANGES NEEDED AT THE MOMENT. && .PREV DISCUSSION... /ISSUED 130 PM CST MON FEB 20 2006/ ABOVE NORMAL TEMPERATURES, LIGHT TO MODERATE SOUTHEAST WINDS AND PARTLY CLOUDY SKIES WILL PREVAIL ACROSS THE RIO GRANDE VALLEY TUESDAY AND WEDNESDAY. A WEAK HIGH PRESSURE RIDGE WILL EXTEND INTO DEEP SOUTH TEXAS THE NEXT FEW DAYS PRODUCING DRIER CONDITIONS. FOG WILL DEVELOP OVER PORTIONS OF THE RIO GRANDE VALLEY AFTER MIDNIGHT TONIGHT BUT THE FOG WILL BURN OFF AFTER SUNRISE TUESDAY MORNING. ABOVE NORMAL TEMPERATURES WILL PREVAIL OVER THE RIO GRANDE VALLEY THROUGH SATURDAY. A COLD FRONT WILL MOVE THROUGH THE RIO GRANDE VALLEY FRIDAY NIGHT INTO SATURDAY MORNING. WINDS WILL INCREASE FROM THE NORTHEAST SATURDAY AFTERNOON IN THE WAKE OF THE FRONT BECOMING MODERATE AND GUSTY. TEMPERATURES WILL DECREASE TO NEAR NORMAL VALUES SUNDAY AND MONDAY IN THE WAKE OF THE FRONT. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO SYNOPTIC/GRIDS...61 MARINE/AVIATION/MESO...60 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 1136 AM CST MON FEB 20 2006 .AVIATION... BACK EDGE OF LOW STRATUS HAS LIFTED EAST OF THE KSJT AND KSWW TERMINALS AT 17Z. EXPECT LOW CLOUDS TO CLEAR THE KABI TERMINAL BY 19Z. RUC40 MODEL PREFERRED OVER THE ETA40 MODEL/S HANDLING OF THE LOW LEVEL MOISTURE THIS MORNING. VFR CIGS/VISIBILITIES EXPECTED THROUGH THE LATE EVENING. BY 06Z...EXPECT MVFR CIGS TO SPREAD NORTHWARD INTO THE HILL COUNTRY...REACHING KJCT BY 06Z AND KSJT A FEW HOURS LATER. SOME QUESTION AS TO WHEN/IF THE LOW CLOUDS WILL MAKE IT INTO KABI. HAVE DECIDED TO INTRODUCE AN MVFR CIG AT KABI TOWARD 12Z...BASED ON THE THE STRENGTH AND POSITION OF THE LOW LEVEL JET. HAVE ALSO INCLUDED A NON CONVECTIVE LOW LEVEL WIND SHEAR IN THE KABI TAF IN THE EARLY MORNING. 14 && .PREV DISCUSSION... (ISSUED 506 AM CST MON FEB 20 2006) AVIATION... FOR KABI...EXPECT LIFR WITH CEILINGS AROUND 400 FT FOR MOST OF THE MORNING. CEILINGS WILL LIFT LATE MORNING AND VFR CONDITIONS WILL PERSIST FOR THE NEXT 24 HOURS. KSJT WILL HAVE VFR CONDITIONS FOR THE NEXT 24 HOURS WITH LIGHT AND VARIABLE WINDS. PREV DISCUSSION... (ISSUED 406 AM CST MON FEB 20 2006) SHORT TERM... EXPECT BELOW NORMAL TEMPERATURES TO CONTINUE ACROSS WEST CENTRAL TEXAS TODAY. LIMITED SUNSHINE TODAY WILL HOLD AFTERNOON HIGHS MAINLY IN THE 55 TO 60 RANGE. RETURN SOUTHEASTERLY FLOW DEVELOPS OVERNIGHT TONIGHT AS THE SURFACE HIGH PRESSURE DOME MOVES EAST ACROSS THE MISSISSIPPI VALLEY. BY TOMORROW AFTERNOON...SURFACE WINDS INCREASE AND BECOME MORE SOUTHWESTERLY IN RESPONSE TO AN APPROACHING COLD FRONT. THE SOUTHWEST WINDS TOMORROW WILL PUSH AFTERNOON HIGHS INTO THE UPPER 60S TO LOWER 70S...WELL ABOVE SEASONAL NORMALS. FRONT TIMING REMAINS SOMEWHAT UNCERTAIN. HOWEVER...DECIDED ON THE GFS TIMING WHICH BRING THE LEADING EDGE OF THE COLD FRONT INTO THE BIG COUNTY BY SUNRISE WEDNESDAY MORNING. AFTERNOON HIGHS WILL BE COOLER WEDNESDAY...ESPECIALLY FOR THE BIG COUNTRY. ALTHOUGH MOISTURE AND DYNAMICS LOOK MARGINAL...WILL CONTINUE 20 POPS FOR TUESDAY NIGHT AND WEDNESDAY. FOR WEDNESDAY NIGHT...OVERNIGHT LOWS WILL BE CLOSER TO SEASONAL NORMALS...THANKS TO ANOTHER SHOT OF COLD AIR. LONG TERM... WITH THE POTENTIAL FOR ANOTHER ROUND OF ISENTROPIC LIFT...WILL CONTINUE POPS FOR THURSDAY AND THURSDAY NIGHT. BEST MOISTURE AND DYNAMICS WILL BE ACROSS OUR SOUTHEASTERN COUNTIES. THUS...WILL GO WITH HIGHER POPS THERE. FOR FRIDAY THROUGH THE WEEKEND...EXPECT DRY CONDITIONS TO RETURN TO WEST CENTRAL TEXAS. ANOTHER COLD FRONT WILL MOVE SOUTH ACROSS WEST CENTRAL TEXAS FRIDAY NIGHT AND SATURDAY. THIS SYSTEM DOES LOOK DRY. HOWEVER...THE FRONT WILL BRING DRIER AIR AND COOL TEMPERATURES TO WEST CENTRAL TEXAS FOR THE WEEKEND. && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1125 AM EST MON FEB 20 2006 .SHORT TERM (REST OF TODAY)... SN WINDING DN IN XTRM SE VA/NE NC...OTRW MCLDY/PSNY THRUT REST OF THE DAY. AVG ACCUMS AOB 1 INCH ACRS SRN VA/NE NC. && .PREVIOUS DISCUSSION... (ISSUED 645 AM EST MON FEB 20 2006) SHORT TERM (REST OF TODAY)...BACK EDGE TO MAIN AREA OF SNOW CURRENTLY LOCATED ALONG I-85/I-95 CORRIDOR...AND TRACKING EAST. MAY BE SOME PIVOTING OF THE MSTR SEWD INTO NC/OVER NXT FEW HRS. HAVE SENT UPDATED ZONES/SPS TO ACCOUNT FOR NXT FEW HRS...EXPECT ONLY SCTD LGT SNOW SHWRS WITH LITTLE TO NO ADDITIONAL ACCUMS N AND W OF AKQ TO NHK LINE...WITH BRIEF MDT SNOW BURSTS IN ERN ZONES THRU ABOUT 8 AM...WHERE ADDITIONAL ACCUMS WILL BE A HALF INCH TO AN INCH. PREVIOUS DISCUSSION... (ISSUED 426 AM EST MON FEB 20 2006) SHORT TERM (TODAY THROUGH WEDNESDAY)...LGT SNOW BEGINNING TO DEVELOP ALIGNED MAINLY FROM CENTRAL NC ENE INTO VA PIEDMONT CNTYS ERLY THIS MRNG...LINING UP FAIRLY WELL WITH H7-8 FRONTOGENESIS BANDS ON RUC/NAM/GFS. MODELS DEPICT SOME STRENGTHENING IN LIFT AND FRONTOGENETIC FORCING BETWN 12 AND 16 Z...ESPECIALLY IN NE NC AND EXTREME SRN VA...SO HAVE FOCUSED IN ON THIS AREA AND TIME FRAME WITH LIKELY TO CAT POPS. PROGRESSIVE NATURE OF THIS SYSTM SHOULD LIMIT ACCUMS TO GENERALLY A DUSTING TO HALF INCH CNTRL/SE VA...TO AROUND AN INCH IN NC. WILL REISSUE SPS BUT WILL HOLD OFF ON ADVSRY FOR NOW...ALTHOUGH WILL CLOSELY MONITOR TRENDS NXT FEW HRS. THICKNESS AND SFC WET BULBS INDICATE CHANGEOVER TO RAIN/SNOW MIX SE VA/NE NC BY LATE MRNG SO THIS WOULD FURTHER INHIBIT HIGHER ACCUMS. AFTER 18Z...LIFT LOOKS TO BE OFFSHORE LEAVING JUST MCDY SKIES LATER THIS AFTN...WITH A FEW BRKS OF SUN CNTRL VA/MD POSBL. AFTER PRECIP ENDS TEMPS WILL RISE INTO LWR 40S MOST AREAS. TONIGHT/TUE...MODEL TRENDS SHUNT MSTR A LITLE FARTHER SOUTH SO HAVE TRIMMED BACK POPS TO GO DRY ALL ZONES TNGT...AND ONLY SCHC IN NC ON TUE. WLY FLOW WILL HELP TEMPS REBOUND TO NEAR NRML TUE. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...NEXT SYSTM WITH BETTER FORCING RETURNING TO AREA LOOKS TO MOVE IN LATE TUE NGT/WED...HAVE INCRSD POPS TO LKLY WED IN SRN 1/2 CWA. PTYPE MAY BE AN ISSUE AT START SO CONTD WITH RA/SN MIX CHANGING TO RAIN. EXCEPTION MAY BE NW ZONES WHEER LOW LVL COLD AIR MAY HANG IN LONGER. MADE NO CHNGES BEYOND WED IN THE FAIRLY PROGRESSIVE PATN THRU THU. PATN THEN LOOKS TO AMPLIFY INTO MORE OF POS PNA WITH POSBL COLD OTBRK AGAIN FRI INTO NXT WEEKND. WILL ALLOW DAY SHIFT TO EVALUATE NXT SET OF MODEL RUNS FOR CONSISTENCY. MARINE...A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL MOVE OUT TO SEA SOUTH OF THE MID ATLC WATERS THRU MIDWEEK WITH GENERALLY BENIGN MARINE CONDS EXPECTED. AVIATION... CIGS/VSBYS WILL BE DETERIORATING RAPIDLY IN THE PREDAWN HOURS AS AREA OF LGT/MOD SNOW MOVES IN. EXPECT MNLY IFR CONDS ALL TAF SITES (EXCEPT SBY ON NORTHERN EDGE OF PCPN SHIELD) THROUGH MIDDAY. SLOW IMPROVEMENT EXPECTED DURING AFTN HOURS AS STEADIER PCPN AND LOWER CLOUD DECKS MOVE OUT. SHUD BE MAINLY VFR ALL AREAS BY NIGHTFALL. AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. $$ SHORT TERM/LONG TERM...BROWN AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. $$ && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM...25 va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 645 AM EST MON FEB 20 2006 .SHORT TERM (REST OF TODAY)...BACK EDGE TO MAIN AREA OF SNOW CURRENTLY LOCATED ALONG I-85/I-95 CORRIDOR...AND TRACKING EAST. MAY BE SOME PIVOTING OF THE MSTR SEWD INTO NC/OVER NXT FEW HRS. HAVE SENT UPDATED ZONES/SPS TO ACCOUNT FOR NXT FEW HRS...EXPECT ONLY SCTD LGT SNOW SHWRS WITH LITTLE TO NO ADDITIONAL ACCUMS N AND W OF AKQ TO NHK LINE...WITH BRIEF MDT SNOW BURSTS IN ERN ZONES THRU ABOUT 8 AM...WHERE ADDITIONAL ACCUMS WILL BE A HALF INCH TO AN INCH. && .PREVIOUS DISCUSSION... (ISSUED 426 AM EST MON FEB 20 2006) SHORT TERM (TODAY THROUGH WEDNESDAY)...LGT SNOW BEGINNING TO DEVELOP ALIGNED MAINLY FROM CENTRAL NC ENE INTO VA PIEDMONT CNTYS ERLY THIS MRNG...LINING UP FAIRLY WELL WITH H7-8 FRONTOGENESIS BANDS ON RUC/NAM/GFS. MODELS DEPICT SOME STRENGTHENING IN LIFT AND FRONTOGENETIC FORCING BETWN 12 AND 16 Z...ESPECIALLY IN NE NC AND EXTREME SRN VA...SO HAVE FOCUSED IN ON THIS AREA AND TIME FRAME WITH LIKELY TO CAT POPS. PROGRESSIVE NATURE OF THIS SYSTM SHOULD LIMIT ACCUMS TO GENERALLY A DUSTING TO HALF INCH CNTRL/SE VA...TO AROUND AN INCH IN NC. WILL REISSUE SPS BUT WILL HOLD OFF ON ADVSRY FOR NOW...ALTHOUGH WILL CLOSELY MONITOR TRENDS NXT FEW HRS. THICKNESS AND SFC WET BULBS INDICATE CHANGEOVER TO RAIN/SNOW MIX SE VA/NE NC BY LATE MRNG SO THIS WOULD FURTHER INHIBIT HIGHER ACCUMS. AFTER 18Z...LIFT LOOKS TO BE OFFSHORE LEAVING JUST MCDY SKIES LATER THIS AFTN...WITH A FEW BRKS OF SUN CNTRL VA/MD POSBL. AFTER PRECIP ENDS TEMPS WILL RISE INTO LWR 40S MOST AREAS. TONIGHT/TUE...MODEL TRENDS SHUNT MSTR A LITLE FARTHER SOUTH SO HAVE TRIMMED BACK POPS TO GO DRY ALL ZONES TNGT...AND ONLY SCHC IN NC ON TUE. WLY FLOW WILL HELP TEMPS REBOUND TO NEAR NRML TUE. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...NEXT SYSTM WITH BETTER FORCING RETURNING TO AREA LOOKS TO MOVE IN LATE TUE NGT/WED...HAVE INCRSD POPS TO LKLY WED IN SRN 1/2 CWA. PTYPE MAY BE AN ISSUE AT START SO CONTD WITH RA/SN MIX CHANGING TO RAIN. EXCEPTION MAY BE NW ZONES WHEER LOW LVL COLD AIR MAY HANG IN LONGER. MADE NO CHNGES BEYOND WED IN THE FAIRLY PROGRESSIVE PATN THRU THU. PATN THEN LOOKS TO AMPLIFY INTO MORE OF POS PNA WITH POSBL COLD OTBRK AGAIN FRI INTO NXT WEEKND. WILL ALLOW DAY SHIFT TO EVALUATE NXT SET OF MODEL RUNS FOR CONSISTENCY. MARINE...A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL MOVE OUT TO SEA SOUTH OF THE MID ATLC WATERS THRU MIDWEEK WITH GENERALLY BENIGN MARINE CONDS EXPECTED. AVIATION... CIGS/VSBYS WILL BE DETERIORATING RAPIDLY IN THE PREDAWN HOURS AS AREA OF LGT/MOD SNOW MOVES IN. EXPECT MNLY IFR CONDS ALL TAF SITES (EXCEPT SBY ON NORTHERN EDGE OF PCPN SHIELD) THROUGH MIDDAY. SLOW IMPROVEMENT EXPECTED DURING AFTN HOURS AS STEADIER PCPN AND LOWER CLOUD DECKS MOVE OUT. SHUD BE MAINLY VFR ALL AREAS BY NIGHTFALL. AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. $$ SHORT TERM/LONG TERM...BROWN && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM UPDATE...BROWN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 316 PM CST MON FEB 20 2006 .SHORT TERM...TONIGHT THROUGH THURSDAY PLENTY TO DIGEST IN THE SHORT TERM...ALTHOUGH NONE OF IT SIGNIFICANT...AS FAST WEST-NORTHWESTERLY NRN STREAM DIVES OUT OF WRN CANADA...WHERE IT PHASES OVER THE GREAT LAKES AND MID ATLANTIC WITH STRONG ZONALLY ORIENTED SUBTROPICAL JET ATOP FLAT GULF COAST RIDGE CREATING A NICE 150KT H3 JET CORE FROM WESTERN LAKES INTO WRN ATLANTIC OCEAN. ARX CWA POSITIONED JUST NORTHWEST OF THE CONFLUENCE REGION OF THE UPPER JETS...MAINLY IN THE LEFT ENTRANCE /SUBSIDENT/ REGION OF THE JET MAXIMUM OFF TO THE SOUTHEAST. NRN STREAM FEEDS US A STEADY DIET OF TRANSIENT...MOISTURE STARVED WAVES COMING ACROSS VAST STRETCHES OF LAND...WITH LITTLE CHANCE TO ENTRAIN DEEPER MOISTURE LOCKED UP SOUTH OF THE MAIN JET AXIS MENTIONED ABOVE. THESE WAVES LINED UP FOR THIS EVENING...TUESDAY EVENING...WEDNESDAY EVENING...AND FRIDAY. TONIGHT...FIRST WAVE LOOKING A LITTLE MORE ROBUST THIS AFTERNOON PER WV LOOPS AND RADAR MOSAICS FROM KMVX/KDLH. PLENTY OF LGT SNOW BREAKING OUT IN THE WARM ADVECTION/ISENTROPIC LIFT AREAS /280- 285K/ AHEAD OF THE SYSTEM ACROSS NORTHERN MINNESOTA. BOTH 18Z RUC AND NAM CONTINUE TO BRUSH NRN CWA THIS EVENING WITH A BAND OF QUICK SATURATION/LIFT. AS STATED ABOVE...OVERALL SYNOPTIC SETUP OVER THE CWA NOT VERY CONDUCIVE TO WIDESPREAD UPWARD VERTICAL MOTIONS...BUT SOME PRETTY DECENT MESOSCALE FRONTOGENETICAL RESPONSE AND ISENTROPIC LIFT IN THE NRN CWA THIS EVE WILL LIKELY BRING A FAST MOVING BAND OF FLURRIES/LIGHT SNOW TO THE NORTH. DON/T EXPECT MUCH ACCUMULATION AT ALL...SAVE FOR TAYLOR COUNTY WHICH MAY PICK UP 1/2 INCH. SHOULD SEE CLEARING INTO THE CWA AFTER MIDNIGHT AND A SLUG OF COLD ADVECTION WHICH WILL BRING MORNING LOWS AGAIN INTO THE SINGLE DIGITS TO AROUND 10 ABOVE. TUESDAY/TUES NIGHT...SHOULD START SUNNY BUT CLOUDS QUICKLY INCREASE IN WARM ADVECTION WING OF NEXT SYSTEM /STILL A BIT STRONGER AND A LITTLE SOUTH OF TONIGHT/. SURFACE RIDGE AXIS CROSSES CWA BY NOON SO RETURN FLOW JUST IN TIME FOR THIS WAVE. TIGHT WAVELENGTH AGAIN PRECLUDES ANY DECENT MOISTURE INTO THIS WAVE. THOUGH...A MORE SOUTHERN TRACK BRINGS STRONGER HEIGHT FALLS/PV ADVECTION ACROSS THE NRN PORTION OF CWA. BETTER SATURATION ON THE 285K SURFACE AND A STRONGER/DEEPER Q/G SIGNAL WHICH CORRESPONDS TO THE OVERALL STRONGER REFLECTION OF THE WAVE ALOFT. INCREASED POPS NORTH OF I-90 /ESPECIALLY CLARK AND TAYLOR COUNTIES/ AND MAY NEED TO GO LIKELY WITH THIS SYSTEM IN THE NORTH WITH PERSISTENT/SOLID SIGNAL IN BOTH NAM/GFS WITH WAVE. STILL...LIGHT ACCUMULATIONS AT BEST. WEDNESDAY/WED NIGHT...ANOTHER PERIOD OF SUBSIDENCE /SHORTWAVE RIDGING/ IN WAKE OF TUES EVENING SYSTEM SO A MIX OF CLOUDS AND SUN LIKELY. FLOW BACKS A LITTLE MORE WLY AHEAD OF WED NIGHT WAVE...SO STILL LOOKS LIKE THE WARMEST DAY...AND GOOD FOR MELTING WITH TEMPERATURES MOVING ABOVE NORMALS. TRACK OF WED NIGHT WAVE MORE NORTHERLY AGAIN SO MAINLY A DRY PASSAGE. TRIMMED POPS BACK AGAIN TO ONLY THE NRN PORTIONS OF CWA. WILL REMAIN MILD OVERNIGHT WITH STRONG COLD ADVECTION HOLDING OFF TIL THURSDAY. THURSDAY...ANOTHER PERIOD OF SUBSIDENCE AND COLD ADVECTION SO A COOLER DAY THAN WED AS 925MB TEMPS FALL BACK TOWARD -10C. MORNING FLURRIES IN THE EAST GIVE WAY TO SUN AND CLOUDS. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY STILL SOME OVERALL DISAGREEMENT IN THE EXTENDED REGARDING JUST HOW AMPLIFIED THE NOAM PATTERN WILL BE FOR THE WEEKEND WHICH WILL AFFECT HOW MUCH ARCTIC AIR IS DUMPED SOUTH IN WAKE OF FRIDAY WAVE. WILL CONTINUE TREND OF BELOW NORMAL TEMPERATURES /20S BY DAY AND SINGLE DIGITS BY NIGHT/ ON THE WEEKEND...WITH MODERATION SEEN INTO MIDDLE OF NEXT WEEK AS WRN RIDGING BEGINS TO DISPLACE COLD NERN CONUS TROUGH. NOT MUCH CONFIDENCE HERE THOUGH...AS BLOCKING AND ANOMALY FIELDS OF THE NCEP MEANS HAVE BEEN DEPICTING COLDER AIR LINGERING A LITTLE MORE INTO NEXT WEEK. ECMWF WITH H85 TEMPS -5 TO -15C SAT AND SUN WITH A VERY TIGHT THERMAL RIBBON DIRECTLY OVERHEAD. GEM ON THE OTHER HAND PRETTY BRUTAL WITH ARCTIC OUTBREAK PER 00Z RUN. DON/T THINK WE WILL SEE BRUNT OF ARCTIC AIR SO CONTINUED WITH SPIRIT OF GOING DATABASE. ALSO A GREAT DEAL OF UNCERTAINTY WITH FRIDAY WAVE AND ITS SNOW ACCUMULATION POTENTIAL. MED RANGE MODELS DO AGREE IT WILL BE A STRONGER WAVE...BUT RIGHT NOW IT SEEMS TO BE THAT THE MAIN TRACK OF THESE WAVES WILL BE TO OUR NORTH. WILL NEED TO WATCH THIS ONE MORE CLOSELY. ALL IN ALL...FRIDAY WAVE SENDS A BRIEF AND COLD /UNCERTAIN HOW COLD/ PUSH ACROSS AREA FOR WEEKEND...THEN MODERATION. DRY AFTER FRIDAY AS STRONG HIGH PUSHES ACROSS AREA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ BINAU wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 430 AM EST TUE FEB 21 2006 .SHORT TERM...TODAY AND TONIGHT GOOD AGREEMENT AMONG MODELS DEPICTING WEAK SURFACE COLD FRONT/TROUGH MOVING THROUGH AREA THIS MORNING...THEN WEAK RIDGING THIS AFTERNOON INTO TONIGHT...FOLLOWED BY ANOTHER TROUGH APPROACHING LATE TONIGHT. AT 500 MB...NORTHERN LAKES SHORTWAVE TROUGH RETREATING EAST THIS MORNING...WEAK SHORTWAVE RIDGING IN ITS WAKE TODAY...ANOTHER WEAKER TROUGH REACHING NORTHERN LAKES REGION LATE TONIGHT. MODEL QPF FIELDS RATHER MEAGER THROUGH TONIGHT. RUC/GFS/WRFXX SHOW VERY LIGHT PRECIPITATION TODAY MAINLY THIS MORNING...THEN DRY TONIGHT...WHEREAS NAM/NGM DRY THROUGH TONIGHT. RESIDUAL VERY MODEST LOW TO MID LEVEL OMEGA LIFT DEPARTING EARLY THIS MORNING...SLIGHT AGAIN LATE TONIGHT...WHILE QVECTOR CONVERGENCE SLIGHT AT BEST TODAY AND SLIGHT TO MODEST TONIGHT. LOW LEVEL CONVERGENCE WEAK INTO THIS MORNING...SLIGHT AGAIN LATE TONIGHT MAINLY NORTH. 280K ISENTROPIC ASCENT WEAK AT BEST LATE TONIGHT...AS CONDENSATION PRESSURE DEFICITS DO DIP TO 20 TO 30 MB IN THE SAGINAW VALLEY PROXIMITY. RELATIVE HUMIDITY PRETTY LIMITED FOR MEASURABLE SNOW AS WELL. 850 TO 500 MB MOISTURE VERY MEAGER THROUGH TONIGHT...AND LOWER MOISTURE MODESTLY GOOD TODAY BEFORE TRENDING DRIER TONIGHT. WILL FOLLOW IDEA OF PREVIOUS FORECAST...WITH NO PRECIPITATION MENTION STRONGER THAN FLURRIES THROUGH TONIGHT...AND THAT MENTION PRIMARILY NORTH WHERE LOW LEVEL MOISTURE WILL BE AIDED BY LAKE MICHIGAN TRAJECTORIES. GOING A FEW DEGREES WARMER TODAY THAN YESTERDAY...AS 850 MB TEMPERATURES SLOWLY MODERATE. && .LONG TERM...WEDNESDAY THROUGH MONDAY DURING THE LONG TERM FORECAST...THE STRONG RIDGE THAT HAS BEEN IN PLACE OVER THE GULF OF ALASKA WILL START TO FLATTEN...CAUSING THE NORTHERN STREAM FLOW TO BECOME SLIGHTLY MORE ZONAL THROUGH FRIDAY. BY THIS WEEKEND THE FLOW BUCKLES AGAIN AS A CLOSED UPPER LOW SETS UP OFF THE PACIFIC NORTHWEST COAST...ALLOWING A RIDGE TO BUILD OVER THE WESTERN CONUS WITH A TROUGH SETTING UP OVER THE NORTHEASTERN STATES. TEMPERATURES WILL MODERATE THROUGH THURSDAY...THEN RETURN TO BELOW NORMAL BEHIND A COLD FRONT THAT WILL MOVE ACROSS THE CENTRAL GREAT LAKES ON SATURDAY. THE NEXT WAVE TO IMPACT THE REGION WILL MOVE ACROSS THE NORTHERN GREAT LAKES ON THURSDAY. THE ASSOCIATED SURFACE LOW IS EXPECTED TO TRACK ACROSS LAKE SUPERIOR TO SOUTHERN QUEBEC. THE 00Z/21 GFS IS AN OUTLIER SHOWING THIS LOW TRACKING ACROSS NORTHERN LOWER MICHIGAN AND BRINGING UP TO AN INCH OF SNOW TO THE NORTHERN HALF OF THE CWA. PREFER THE SOLUTION OFFERED UP BY THE MAJORITY OF OTHER MODELS SHOWING A MORE NORTHERN TRACK. A BROAD UPPER LEVEL TROUGH WILL BE SETTING UP OVER MOST OF THE NORTHERN CONUS AT THIS TIME...MAKING IT HARD FOR THIS LOW TO TRACK SOUTHEAST TOWARDS NEW YORK STATE. WILL CONTINUE WITH LOW CHANCE OF SNOW SHOWERS FOR THURSDAY IN THE NORTH WITH A PERIOD OF WEAK LIFT AS THE COLD FRONT SLIDES SOUTH. AM NOT ANY ACCUMULATION AT THIS TIME. SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL HELP TEMPERATURES WARM TO NEAR TO JUST ABOVE NORMAL FOR WEDNESDAY AND THURSDAY. EXACTLY HOW WARM WE GET ON THURSDAY WILL DEPEND ON FRONTAL TIMING BUT WOULD EXPECT THE SOUTHEASTERN CWA TO SEE TEMPS CLIMBING TO JUST ABOVE 40 AHEAD OF THE FRONT. WILL LEAN TOWARDS THE ECMWF FOR THE REMAINDER OF THE FORECAST AS THE GFS NEVER SEEMS TO GET BACK ON TRACK AFTER THE THURSDAY SYSTEM. THE ECMWF IS STILL ABOUT 12 HOURS BEHIND THE GFS FOR THE FRONTAL PASSAGE ON SATURDAY WITH THE REST OF THE MODELS SOMEWHERE IN BETWEEN. HAVE REMOVED PRECIP FOR FRIDAY WITH HIGH PRESSURE EXPECTED OVER THE CENTRAL GREAT LAKES. GOOD ISENTROPIC LIFT MOVES OVER THE AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF THE LOW BRINGING OUR BEST CHANCE FOR SNOW THIS WEEK. GOOD UPPER LEVEL DIVERGENCE WILL ALSO BE OVER THE AREA AND EXPECT TO SEE SOME LIGHT ACCUMULATIONS BY MIDDAY ON SATURDAY. A BLAST OF COLD AIR FILTERS IN OVER THE REGION THIS WEEKEND WITH 850MB TEMPS DROPPING TO -18 TO -20C. TEMPERATURES WILL BE BELOW NORMAL THROUGH THE BEGINNING OF NEXT WEEK WITH HIGHS IN THE LOW TO MID 20S FOR SUNDAY AND MONDAY. SNOW SHOWERS ARE POSSIBLE THROUGH SUNDAY NIGHT WITH COLD CYCLONIC FLOW OVER THE AREA AND THE POTENTIAL FOR SOME LAKE EFFECT SNOW SHOWERS. && .PREV DISCUSSION...ISSUED 1145 PM EST MON FEB 20 2006 AVIATION... ISSUED 628 PM. A MID LEVEL SHORT WAVE TROUGH OVER NORTHERN WISCONSIN HAS AN ASSOCIATED AREA OF LOW PRESSURE CENTERED OVER EASTERN LAKE SUPERIOR. THIS UPPER WAVE AND ASSOCIATED SURFACE LOW WILL MOVE INTO ONTARIO THROUGH EARLY MORNING...SENDING A COLD FRONT ACROSS SE MICHIGAN BETWEEN 09Z AND 15Z. SOUTHWEST FLOW AHEAD OF THIS FRONT AND AMPLE INSTABILITY OFF LAKE MICHIGAN SHOULD SUSTAIN LAKE EFFECT CLOUDS ACROSS THE STATE. INVERSION HEIGHTS WILL REMAIN AROUND 4K FT...SO EXPECT MOST OF THE CLOUDS WILL BE VFR. ADDED LOW LEVEL CONVERGENCE LATE TONIGHT/EARLY TUES MORNING SHOULD BRING A SOME MVFR CEILINGS INTO THE AREA. THIS SHOULD ALSO ENHANCE SNOW SHOWER/FLURRY ACTIVITY...ESPECIALLY NORTH OF PTK. INVERSIONS WILL ALSO FALL BEHIND THIS FRONT. WITH LINGERING LOW LEVEL MOISTURE AND INSTABILITY OFF THE GREAT LAKES...SEVERAL HOURS OF MVFR CEILINGS ARE EXPECTED THIS MORNING. A BRIEF SHOT OF COLD AIR ADVECTION SHOULD ALSO CAUSE THE WINDS TO INCREASE TO 15 TO 20KTS. WEAK SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION TUES AFTERNOON ALONG WITH STRONG DRY AIR ADVECTION ATOP THE MIXED LAYER. THIS WILL RESULT IN IMPROVING CONDITIONS THROUGH THE AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421-LHZ441 UNTIL NOON TUESDAY. SMALL CRAFT ADVISORY...LHZ442-LHZ443 UNTIL 6 AM TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DWD LONG TERM....KAHL AVIATION...CONSIDINE 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 338 AM EST TUE FEB 21 2006 .DISCUSSION... MAIN FORECAST CONCERNS ARE ONGOING LES AND LIGHT SNOW TONIGHT. CURRENT WEATHER...09Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A SPLIT FLOW PATTERN...WITH THE NORTHERN STREAM IN A GENERAL NW FLOW EXTENDING FROM WESTERN CANADA INTO THE GREAT LAKES...AND THE SOUTHERN STREAM LOCATED FROM BAJA CALIFORNIA ENE TO THE CAROLINAS. WITHIN THE NORTHERN STREAM...A FAIRLY STRONG SHRTWV TROUGH CROSSED UPPER MICHIGAN OVERNIGHT AND NOW HAS MOVED TO NORTHERN LAKE HURON. A 1005MB LOW WAS LOCATED NEAR SUDBURY ONTARIO ASSOCIATED WITH THE SHRTWV TROUGH. LOW LEVEL CONVERGENCE ALONG THE COLD FRONT...COMBINED WITH LAKE ENHANCEMENT FROM MOISTURE ASSOCIATED WITH THE SHRTWV... AIDED IN THE DEVELOPMENT OF HEAVY SNOW ACROSS THE KEWEENAW PENINSULA LAST EVENING...WITH VISIBILITIES OF 1/4SM AT CMX. SPOTTER REPORT FROM THE LAKE LINDEN AREA RECEIVED AT 1015 PM STATED THAT 6 INCHES OF SNOWFALL OCCURRED SINCE 630 PM WITH AN 1/8SM VISIBILITY CONTINUING. THE SAME SPOTTER CALLED BACK AT 11 PM WITH AN ADDITIONAL 3.5 INCHES. KMQT RADAR AT THE TIME SHOWED NEARLY 20DBZ RETURNS AT 13000 FT. 00Z KINL SOUNDING EXPLAINS WHY THE SNOW WAS SO INTENSE... WITH A NEARLY SATURATED LAYER BETWEEN THE SURFACE AND 700MB...ALONG WITH AN INVERSION AT 650MB...PROMOTING INTENSE LAKE ENHANCEMENT. WITH THE COLD FRONT NOW PUSHED SOUTH INTO ONTONAGON AND ALGER/NORTHERN LUCE COUNTIES...THE HEAVIEST SNOW HAS LEFT THE KEWEENAW. COLD AIR ADVECTION BEHIND THE FRONT ALONG WITH A NW TO N LOW LEVEL FLOW HAS RESULTED IN SOME MULTI-PARALLEL BANDS ACROSS THE KEWEENAW PENINSULA AS SEEN ON IR SATELLITE IMAGERY...HOWEVER LITTLE IF ANY BANDS ARE PRESENT WEST OF THERE. 05Z TAMDAR SOUNDING FROM INL SHOWED AN INVERSION NOW AT 800MB...INDICATIVE OF STRONG SUBSIDENCE BEHIND THE SHRTWV. AWAY FROM THE COLD FRONT...LITTLE IN THE WAY OF SYNOPTIC SNOW IS OCCURRING THANKS TO DRY AIR SEEN ON THE 00Z GRB...MPX AND APX SOUNDINGS. TO THE WEST...A HIGH PRESSURE RIDGE WAS BUILDING INTO MINNESOTA. FARTHER WEST...ANOTHER SHRTWV CAN BE SEEN DROPPING SOUTH THROUGH SASKATCHEWAN...AND PRESSURES FALLS ARE ALREADY OCCURRING ACROSS THE DAKOTAS. TODAY...SHRTWV OVER NORTHERN LAKE HURON SHOULD CONTINUE PROGRESSING QUICKLY OFF TO THE EAST IN THE FAST FLOW ALOFT. AS A RESULT...LOW LEVEL FLOW WILL BECOME INCREASING ANTICYCLONIC AS THE HIGH PRESSURE RIDGE BUILDS INTO THE AREA. IN FACT...BY 00Z...MODELS PROG THE LOW LEVEL FLOW TO BECOME SOUTHWESTERLY AHEAD OF THE SOUTHERN SASKATCHEWAN SHRTWV. LAKE EFFECT/ENHANCED SNOW SHOWERS CURRENTLY GOING ON ARE THEREFORE EXPECTED TO DIMINISH WITH THE CHANGE IN LOW LEVEL FLOW...STRONG SUBSIDENCE AND DRY AIR INTRUSION. HAVE FOLLOWED THE RUC AND OUR LOCAL WRF RUN FOR LES TRENDS...WHICH ALL SHOW LITTLE IN THE WAY OF QPF THIS MORNING. HAVE DROPPED ALL HEADLINES GIVEN THAT THE LES IS TURNING OUT TO BE LESS THAN EXPECTED. OTHER THAN LAKE EFFECT CLOUDS...HIGH CLOUDS WILL MOVE IN LATER THIS AFTERNOON. THEREFORE...IN GENERAL EXPECTING SKIES TO BE PARTLY SUNNY. TEMPERATURES SHOULD BE A FEW DEGREES COOLER THAN YESTERDAY DUE TO THE CLOUD COVER AND 850MB TEMPS AROUND 2C COLDER. TONIGHT...SOUTHERN SASKATCHEWAN SHRTWV IS PROGGED TO CROSS THE AREA...REACHING THE EASTERN U.P. BY MORNING. THIS SHRTWV LOOKS STRONGER ON WATER VAPOR AND IN FACT...MODELS HAVE TRENDED STRONGER...ESPECIALLY THE UKMET. ISENTROPIC LIFT INCREASES QUICKLY IN THE EVENING (SEE 275-280K SURFACES) WITH CONDENSATION PRESSURE DEFICITS NEAR 0. THEREFORE EXPECTING SYNOPTIC SNOW TO CROSS THE CWA. MODEL FORECAST SOUNDINGS LOOK PRETTY DECENT FOR SNOWFALL TOO WITH OMEGA MAXIMIZED IN THE DENDRITIC SNOW GROWTH LAYER (APPROX 4000 FT DEEP). THE BIGGEST CONCERN FOR THIS SYSTEM IS THAT THE AIRMASS INITIALLY OVER UPPER MICHIGAN WILL BE DRY...BUT THINK THAT THE LIFT ALONG WITH THE MOISTURE ADVECTION SHOULD BE ENOUGH TO SQUEEZE OUT AN INCH OR TWO OF SNOWFALL. DAY SHIFT WILL NEED TO MONITOR THIS SYSTEM AND HOW MUCH SNOW FORMS ACROSS THE NORTHERN PLAINS/MINNESOTA. HAVE WENT A FEW DEGREES ABOVE GUIDANCE FOR LOW TEMPERATURES GIVEN A SOUTHWEST WIND AND PLENTY OF CLOUD COVER. WEDNESDAY INTO WEDNESDAY NIGHT...REPEAT THE PATTERN OF TODAY AND TONIGHT. MODELS SHOW ANOTHER WEAK HIGH PRESSURE RIDGE MOVING INTO THE AREA WEDNESDAY AFTERNOON WHILE ANOTHER CLIPPER SHRTWV (LOCATED IN THE NORTHERN PORTION OF THE GULF OF ALASKA) DROPS INTO THE NORTHERN PLAINS. SOME LAKE EFFECT SNOW MAY BE ONGOING WEDNESDAY MORNING SINCE FLOW IS WESTERLY...BUT THIS WILL TAPER OFF IN THE AFTERNOON AS THE LOW LEVEL FLOW TRIES TO BACK. ALTHOUGH SKIES MAY CLEAR SOME DURING THE MORNING...HIGH CLOUDS WILL BEING INCREASING DURING THE AFTERNOON ASSOCIATED WITH THE NEXT CLIPPER SHRTWV. 850MB TEMPS ON THE ORDER OF -11C COMBINED WITH SOME SUN SHOULD ALLOW SURFACE TEMPERATURES TO CLIMB TO NEAR 30F. CLIPPER WILL THEN MAKE ITS WAY ACROSS SOUTHERN WISCONSIN WEDNESDAY NIGHT...WITH A SURFACE LOW MOVING TO UPPER MICHIGAN BY 12Z. ISENTROPIC LIFT AHEAD OF THIS CLIPPER WILL LIKELY BRING ANOTHER AREA OF LIGHT SNOW ACROSS UPPER MICHIGAN FOLLOWED BY LAKE EFFECT BEHIND IT ON NW WINDS. HAVE RAISED POPS TO LIKELY AFTER MIDNIGHT WEDNESDAY NIGHT FOR THE HIGHER TERRAIN AREAS OF WESTERN UPPER MICHIGAN FOR THE LAKE EFFECT. LOW TEMPERATURES AGAIN SHOULD BE KEPT UP DUE TO CLOUD COVER. THURSDAY THROUGH FRIDAY...COLD AIR ADVECTION BEHIND WEDNESDAY NIGHT\S CLIPPER (DROPPING 850MB TEMPS TO -16 TO -18C) WILL PROMOTE LAKE EFFECT SNOW SHOWERS ACROSS THE NORTHERN U.P. WITH A FEW FLURRIES INLAND FOR THURSDAY. HIGH PRESSURE IS THEN PROGGED TO BUILD INTO THE AREA THURSDAY NIGHT INTO FRIDAY AS FLOW TURNS MORE ZONAL ACROSS THE NORTHERN U.S.. THIS ZONAL FLOW CREATION IS CAUSED BY A SHRTWV DROPPING SOUTH THROUGH BRITISH COLUMBIA ON THU AND INTO THE NORTHERN PLAINS ON FRI. THURSDAY NIGHT MAY END UP SOMEWHAT CHILLY OVER THE INTERIOR WEST HALF AS WINDS BECOME LIGHT UNDER THE HIGH AND SKIES CLEAR OUT. HAVE LEFT LOW TEMPERATURES ALONE AT THE MOMENT...BUT MAY NEED SOME ADJUSTING DOWNWARD IF THE TREND OF HAVING HIGH PRESSURE OVERHEAD CONTINUES. ON FRIDAY...LOW PRESSURE WILL MOVE THROUGH THE NORTHERN PLAINS AHEAD OF THE SHRTWV...BUT IT\S EFFECTS APPEAR TO HOLD OFF OVER UPPER MICHIGAN UNTIL FRIDAY NIGHT. HAVE MAINTAINED THE LAKE EFFECT SNOW CHANCES FOR THURSDAY NIGHT AND FRIDAY...BUT THESE MAY NEED TO BE PULLED...AGAIN IF THE HIGH PRESSURE OVERHEAD IDEA CONTINUES. EXTENDED...NO CHANGES MADE. GFS/UKMET/ECMWF ALL SHOW THE LOW IN THE NORTHERN PLAINS MOVING EASTWARD ACROSS THE WESTERN GREAT LAKES FRIDAY NIGHT INTO SATURDAY...BUT THE PRECISE TRACK AND INTENSITY ARE STILL IN QUESTION. 00Z GFS APPEARS TO BE AN OUTLIER WITH A COMPACT DEEP LOW. THEREFORE READINGS WILL NOT GET AS COLD AS MEX GUIDANCE NUMBERS MAY SUGGEST. SNOW CHANCES ARE STILL ON TRACK...HOWEVER...AS 850MB TEMPS DO DROP DOWN INTO THE -15 TO -20C RANGE FOR THE WEEKEND. HIGH PRESSURE THAT BUILDS SOUTH THROUGH THE PLAINS DURING THE WEEKEND IS THEN PROGGED TO MOVE OVER THE CWA BY MONDAY AS AN UPPER TROUGH LOCKS ITSELF UP OVER THE NORTHEAST (DUE TO DOWNSTREAM RIDGING OVER THE NORTH ATLANTIC). BEYOND MONDAY...A BLOCKED UP PATTERN IS EXPECTED TO EVOLVE...WITH A STRONG RIDGE OVER GREENLAND...A TROUGH OVER NEW ENGLAND...A RIDGE IN THE PLAINS AND A TROUGH JUST OFF THE WEST COAST. WITH THIS SETUP...THE HIGH PRESSURE AREA WILL LIKELY GO NOWHERE...SO TEMPERATURES SHOULD REMAIN AROUND NORMAL. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1111 PM CST MON FEB 20 2006 .DISCUSSION... FOR THE SECOND STRAIGHT DAY...EXTENSIVE CLD COVER HAS REALLY HAMMERED AFTN TEMPS. CLRG HAS FINALLY SPED UP A BIT OVR OUR N COUNTIES WHERE W LO LVL FLO IS A BIT STGR AND I THINK THAT THE CLRG WL WORK E OVRNGT...BUT ANTICIPATE THAT IT WL SLOW DOWN A BIT AFT SNST. ANTICIPATING THAT THE CLRG WL EVENTUALLY WORK INTO E COUNTIES... HV KEPT TNGTS MINS IN THE LM 20S OVR MOST AREAS BUT DID DROP THEM INTO THE TEENS OVR FAR SOUTHEAST COUNTIES WERE SNOW COVER LINGERS. RADIATIONAL COOLING SHUD ALSO ALLOW TEMPS TO FALL TO DWPT OVR THE SNW FIELD..SO HV ALSO MENTIONED AREAS OF FOG IN THIS AREA AFT MIDN. RMNTS OF HIGH WL RMN OVR MID MS VLY ON TUE WHILE MID LVL WHILE W SECTION OF UPR TROF OVR CA CST DRIFT S. RESULTANT FAST ZNL FLO OVR FA APR TO BE POSED TO BRING ANOTHER ROUND OF CLDNS INTO AREA ON TUE AFTN/EVE...WHICH MAY ONCE AGAIN LIMIT WRMUP OVR AREA. WL STICK WITH GOING FCST WHICH IS A FEW DEGREES COOLER THAN 12Z MOS...AND ALSO CONTINUES EMPHASIS OF SLGTLY COOLER TEMPS OVR SNW FIELD IN SE. PCPN THRT WL ALSO RMN IN THE FCST FOR TUE NGT. ALTHO 12Z RUNS ARE NOT QUITE A EXCITED ABT THIS AND WAA INTO AREA DOESN'T LK QUITE AS STG AS ERYR...SHTWV ENERGY APRS TO BE A BIT STGR. UA PTRN UNDERGOES A SGNFT CHG HEADING INTO NXT WEEKEND WITH HGTS LWRG OVR NE U.S. AND RDG DVLPG OVR ROCKIES...BUT SPECIFICS OF THIS CHG STILL VERY MUCH IN DOUBT. GFS IS STILL FCSTG CUTOFF LO OVR NE WHICH RESULTS IN A RETURN OF VRY COLD AIR BACKING INTO THE MID MS VLY...WHILE ECMWF KPS MAIN LO OVER HUDSONS BAY WITH A TROF EXTENDING INTO NE...MAKING COOL DOWN MUCH LESS DRAMATIC. AND...EACH RUN OF THE ECMWF HAS BEEN DELAYING ONSET OF THE INITIAL SURGE OF COLD AIR. SHTWVS EMBDD IN THE FAST UA FLO WL SWING SVRL WK FRONTS INTO THE AREA IN THE WED-FRI TIME FRAME...BUT IT APRS THAT ANY DEEP SWD PENETRATION OF THE CDAIR WL BE WEAK SO TEMPS SHUD RMN FAIRLY MILD. COLDEST AIR SHUD ARRIVE SAT-SUN...BUT ONCE AGAIN HV OPTED TO NOT GO AS COLD AS MOS GUIDANCE. HV KEPT POPS BLO CLIMO...ALTHO WE'LL NEED TO WATCH FRI NGT/SAT. IF MAIN SHTWV ENDS UP BEING AS INTS AS FCST BY GFS MAY NEED TO INTRO POPS AT A LTR TIME. TRUETT && .AVIATION... FOR THE 06Z TAFS...WKNG SFC TROF OVR THE NRN PLAINS WILL MOVE SEWD THRU NRN PTNS OF MO AND IL LTR TGT. LTL EFFECT ON FCST EXCEPT FOR THE SFC WND VEERING TO A NWLY DIRECTION IN UIN LT TGT AND EARLY TUE MRNG. SFC WNDS MAY VEER SLIGHTLY TO A W-SWLY DIRECTION FURTHER S IN COU AND STL BY 12Z TUE. SFC WNDS WILL RETURN TO A SLY DIRECTION BY TUE AFTN WITH SFC RDG EXTDG FM THE GULF COAST REGION NW INTO SERN MO AT 18Z TUE. STRATUS CLOUDINESS CURRENTLY OVR SRN MO SHOULD REMAIN S OF COU AND STL TAF SITES WITH 925 MB PROFILER WNDS SHOWING A W-NWLY FLOW. LATEST RUC ANALYSIS ALSO SHOWS HIGH RH AT 925 MB OVR SRN MO ADVCTG SEWD LT TGT. MDLS DEPICT SOME MID LVL CLOUDINESS ARND 700 MB MOVG E-NEWD THRU MUCH OF THE CWA LT TUE AFTN INTO TUE EVNG AHD OF MID-UPR LVL TROF AND ASSOCIATED WK SFC TROF MOVG EWD THRU THE CWA TUE EVNG. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 405 AM CST TUE FEB 21 2006 .SHORT TERM...TODAY THROUGH THURSDAY NIGHT UPPER WAVE AND ASSOCIATED SFC LOW STILL ON TRACK TO SLIDE SE OUT OF CANADA THIS MORNING...MOVE ACROSS THE DAKOTAS AND MAKE ITS WAY INTO MN BY EARLY THIS EVENING. BEST LIFT NOTED BY GFS/NAM/RUC ACROSS NE CWA AND POPS WERE LEFT HIGHEST IN THIS LOCATION. SFC OBS UPSTREAM IN WESTERN ND/SOUTHERN CANADA HAVE SHOWN LIGHT SNOW MOST OF THE NIGHT AND EXPECT SOME OF THIS ACTIVITY TO MAKE IT INTO THE NE CWA BY LATE MORNING AND EARLY AFTERNOON. AS SFC TROUGH SLIDES ACROSS AREA...LIGHT SOUTH WINDS IN THE MORNING WILL GRADUALLY TURN TO THE SW THEN W THROUGHOUT THE DAY. EXPECT BREEZY CONDITIONS TO DEVELOP ACROSS MISSOURI RIVER VALLEY. NEXT WAVE IN PROGRESSIVE PATTERN SLIDES SE ON WED NIGHT. RATHER UNIMPRESSIVE LOOKING SYSTEM AND CURRENT SLIGHT CHANCE POPS STILL SEEM APPROPRIATE. WEAK SFC HIGH AND MID LEVEL RIDGING THEN MOVES IN FOR THURS AND SHOULD BE A FAIRLY QUIET DAY. IT WILL BE COLDER AS A COLD FRONT WILL SLIP SOUTH ACROSS THE CWA BEHIND WED NIGHT SYSTEM. TEMPERATURES WERE CHANGED LITTLE AS QUICK MOVING WAVES WILL BRING SHORT PERIODS OF WAA AND CAA THROUGH THE AREA DURING THE PERIOD. DID NOT WANT TO STRAY TOO FAR FROM INHERITED FORECAST UNTIL PERIODS GET CLOSER AND INFLUENCE OF WAA/CAA CAN BE BETTER DEFINED. .LONG TERM...FRIDAY THROUGH MONDAY MODELS AGREE BETTER NOW ON THE TRACK OF THE SURFACE LOW PRESSURE AREA AFFECTING THE REGION IN THE FRIDAY/FRIDAY NIGHT TIME PERIOD. WITH DIFFERENCES IN THE SPEED AND STRENGTH OF THE SURFACE LOW PRESSURE AREA...THE MODELS AGREE MORE THAT THE LOW TRACK WILL BE TO THE NORTH OF OUR CWA. THE ECMWF TRACK WAS FURTHER SOUTH ALONG THE ND/SD BORDER WHILE THE NAM AT 84 HOURS HAD THE SURFACE LOW FURTHER NORTH INTO SOUTHERN CANADA. THUS...KEPT A 20 POP FOR SNOW ACROSS THE NORTHERN PART OF THE CWA AND THAT MAY BE A STRETCH IF THE LOW TRACK IS WELL TO THE NORTH. ALSO...FRIDAY'S TEMPERATURES WILL BE INTERESTING IN THE WARM SECTOR IF THE SFC LOW IS WELL TO THE NORTH. TEMPERATURES MAY BE EVEN WARMER THAN THE CURRENT FORECAST. OTHERWISE...IT LOOKS LIKE STRONG CAA WILL OCCUR IN BEHIND THE LOW WITH POSSIBLY A PERIOD OF WINDY CONDITIONS FRIDAY AFTERNOON AND NIGHT. THE REST OF THE EXTENDED LOOKS DRY WITH BELOW NORMAL TEMPERATURES AS LARGE SURFACE HIGH PRESSURE DOMINATES THE WEATHER. THE DEVELOPMENT OF THE UPPER LOW OVER THE EASTERN UNITED STATES WILL AFFECT THE MOVEMENT OF THE FRONTAL BOUNDARY ACROSS OUR REGION. IT LOOKS AS IF SUNDAY AND MONDAY WILL BE COOLER THAN PREVIOUS FORECAST AS COLDER AIR HOLDS IN...ESPECIALLY ACROSS THE EAST. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ TT/DM sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 300 AM CST MON FEB 20 2006 .DISCUSSION...SAW SOME OPEN SKY YESTERDAY AFTERNOON...WHICH ALLOWED AFTERNOON TEMPERATURES TO RISE QUICKLY. AFTER SOME LIGHT MORNING FOG...ANTICIPATE THE SAME TODAY...WITH INITIAL LOW CLOUDS MIXING OUT AND TEMPERATURES GETTING INTO THE UPPER 70S ACROSS DEEP SOUTH TEXAS BY THIS AFTERNOON. A THIN LAYER OF COOLER AIR REMAINS AT AROUND 5000 FT...AND WILL SLOWLY MIX AWAY. A WEAK REMNANT BOUNDARY PERSISTS OFFSHORE...EVIDENT ON IR SATELLITE...AND SHOULD ALSO ERODE WITH LITTLE CONSEQUENCE. THE BELOW PREVIOUS DISCUSSION STILL SUMMARIZES THE CURRENT FORECAST WELL. STILL EXPECTING A WEAK BACK DOOR FRONT ON THURSDAY...AS A ZONAL H5 PATTERN WITH A SHORT WAVE RIDGE JUST UPSTREAM KEEPS THE MAIN HIGH PRESSURE CENTER GLIDING TOWARD THE LOWER MISSISSIPPI VALLEY. WILL KEEP SLIGHT CHANCE CATEGORY POPS IN THE FORECAST FOR LATE THURSDAY AND EARLY FRIDAY AS A RESULT. MAINLY THOUGH IT WILL BE CLOUD COVER THAT HELPS KEEP TEMPERATURES SLIGHTLY LOWER DURING THE DAY...AS LOW LEVEL THICKNESSES ARE NOT PROGGED TO DECREASE SIGNIFICANTLY WITH THE LATE WEEK AIR MASS. THE SAME CAN NOT BE SAID FOR THE FRONT EXPECTED THIS COMING SATURDAY. THICKNESSES WILL DECREASE AS A CANADIAN AIR MASS PLUNGES SOUTH...AND WITH A ZONAL H5 PATTERN...THE AIR MASS WILL NOT BE AS EASILY DEFLECTED. THE WEATHER BEHIND SATURDAY'S FRONT WILL TEND TO RESEMBLE THAT EXPERIENCED THIS LAST WEEKEND...WITH AN INCREASED CHANCE FOR LIGHT RAIN AND DRIZZLE...OVERCAST SKIES AND COOL TEMPERATURES. PROGGED TEMPERATURES SUGGEST ONLY A MODERATE COOL DOWN...WITH 50S FOR NEXT MONDAY MORNING...BUT WOULD NOT BE SURPRISED TO SEE THE MODELS ADJUST TEMPERATURES A BIT DOWNWARD OVER TIME...AS THEY PICK UP AND COMPENSATE FOR THE SHALLOW AIR MASS. && .MARINE...BUOY 42020 REPORTED EAST WINDS NEAR 2 KNOTS GUSTING TO NEAR 4 KNOTS WITH SEAS AT 3 FEET WITH A PERIOD OF 6 SECONDS AT 01 CST/07 UTC. A WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL BRING LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS TO THE ADJACENT COASTAL WATERS OF DEEP SOUTH TEXAS THIS WEEK. SMALL CRAFT ADVISORY WINDS AND SEAS WILL LIKELY DEVELOP LATE IN THE WEEKEND IN THE WAKE OF A STRONG COLD FRONT. && .AVIATION...MVFR/IFR CONDITIONS WILL PREVAIL THIS MORNING AS LOW CLOUDS AND FOG PREVAIL. VFR CONDITIONS WITH DECREASING CLOUDINESS WILL DEVELOP BY THE AFTERNOON HOURS AND PERSIST THROUGH THE EVENING HOURS. && .PREV DISCUSSION...810 PM CST MON FEB 20 2006...RUC 200MB WIND/WIND SPEED ANALYSIS INDICATED SUBTROPICAL JET MOVING ACROSS THE EASTERN UNITED STATES WITH A NEARLY ZONAL FLOW ACROSS THE SOUTHERN TIER OF THE COUNTRY EXCEPT OVER CALIFORNIA WHERE A 500MB LOW CONTINUES TO DRIFT SLOWLY SOUTHWARD. SHALLOW COLD AIR ACROSS THE SOUTHEAST UNITED STATES HAS MOVED AWAY FROM WEST TX THIS EVENING AS WARM AIR ADVECTION HAS DEVELOPED ACROSS WEST TX. MSAS SURFACE ANALYSIS INDICATED A STATIONARY BOUNDARY WAS DRAPED ACROSS A SURFACE LOW OFFSHORE THE LOWER TX COAST AND COASTAL BEND. ONSHORE FLOW EXPECTED TO DEVELOP TONIGHT WITH LOW PRESSURE OVER WEST TX AND HIGH PRESSURE OVER THE SOUTHEAST UNITED STATES. FOG LIKELY TO DEVELOP ACROSS THE LOWER RIO GRANDE VALLEY TONIGHT WITH NEARLY SATURATED AIR BELOW 850MB AS INDICATED ON 00Z KBRO SOUNDING. WILL UPDATE ZONES/GRIDS TO ADJUST CLOUD COVER TONIGHT. WARMER TEMPERATURES EXPECTED THE NEXT COUPLE OF DAYS BUT STILL QUITE A BIT OF UNCERTAINTY TOWARDS THE END OF THE WEEK AS LATEST GFS RUN PROGS A COLD FRONT MOVING INTO SOUTH TX THURSDAY WITH HIGH PRESSURE OVER THE SOUTHERN PLAINS WEDNESDAY MOVING EASTWARD. ANOTHER FRONT IS EXPECTED TO MOVE INTO SOUTH TX SATURDAY WITH HIGH PRESSURE SURGING ACROSS THE CENTRAL UNITED STATES. COOL AND CLOUDY CONDITIONS LIKELY TO RETURN FOR THE END OF THE WEEKEND WITH A SLIGHT CHANCE OF RAIN. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW 77 66 82 66 75 65 / 00 00 00 05 20 20 BROWNSVILLE 78 65 84 65 78 63 / 00 00 00 05 20 20 FALFURRIAS 79 59 82 59 72 58 / 00 00 00 05 20 20 HARLINGEN 79 66 85 63 76 63 / 00 00 00 05 20 20 HEBBRONVILLE 79 59 84 61 74 58 / 00 00 00 05 20 20 MCALLEN 79 65 86 65 79 64 / 00 00 00 05 20 20 PORT ISABEL 77 65 78 66 76 65 / 00 00 00 05 20 20 RIO GRANDE CITY 81 60 88 64 77 61 / 00 00 00 05 20 20 SOUTH PADRE ISLAND 75 65 78 66 74 66 / 00 00 00 05 20 20 && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 54/66 THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CARIBOU ME 1025 AM EST TUE FEB 21 2006 .SYNOPSIS...WEAK LOW PRESSURE WILL APPROACH FROM THE WEST AND CROSS THE AREA TODAY WITH SOME LIGHT SNOW AND SCATTERED SNOW SHOWERS. ANOTHER WEAK AREA OF HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER TONIGHT AND INTO WEDNESDAY. THE NEXT CHANCE OF MEASURABLE SNOWFALL WILL BE THURSDAY AFTERNOON AND EVENING AS ANOTHER ALBERTA CLIPPER LOW PRESSURE SYSTEM APPROACHES THE REGION FROM THE WEST. && .UPDATE /REST OF TODAY/... UPDATED SNOW AMT & POPS GRIDS FOR THIS AFTERNOON PER LATEST RADAR & SATL TRENDS. LIGHT SNOW MOVING IN SOONER THAN GUIDANCE SUGGESTED. DECIDED TO MOVE TIMING UP BY 3 HRS & EXTENDED AREAL COVERAGE USING LATEST RUC & 06Z NAM. MASSAGED WINDS FIELDS. NO OTHER CHGS MADE. ZFP ALREADY SENT W/THE CHGS. && .MARINE... NO CHGS. && .PREVIOUS DISCUSSION... /ISSUED 256 AM EST TUE FEB 21 2006/ SHORT TERM /TODAY THROUGH WEDNESDAY/... THE MAIN FORECAST CONCERN IN THE SHORT TERM WILL BE WITH REGARD TO THE WEAK CLIPPER TYPE SYSTEM THAT WILL AFFECT THE AREA TODAY. NAM/GFS IN GOOD AGREEMENT WITH REGARD TO SYSTEM. WILL GO LIKELY POPS ACROSS THE NORTH AND WEST ZONES THIS AFTERNOON BASED ON UPSTREAM OBSERVATIONS. WILL ALSO CARRY CHANCE POPS ALL THE WAY TO THE COAST BASED ON POSITION AND STRENGTH OF THE SHORT WAVE SHOWN BY BOTH THE NAM/GFS. EXPECT SNOW ACCUMULATIONS ACROSS THE NORTH ABOUT AN INCH OR SO WITH LESS THAN AN INCH CLOSER TO THE COAST. THE SHORT WAVE WILL EXIT INTO NEW BRUNSWICK EARLY THIS EVENING. EXPECT ANY LINGERING SNOW SHOWERS THIS EVENING TO GIVE WAY TO PARTIAL CLEARING OVERNIGHT ALL AREAS AS WEAK RIDGING BUILDS ACROSS THE AREA. EXPECT MAINLY DRY CONDITIONS ON WEDNESDAY ALTHOUGH CLOUDS WILL BE ON THE INCREASE AHEAD OF THE NEXT SYSTEM APPROACHING FROM THE WEST. LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... SHORT AND MED RANGE MODELS MSLY AGREE THAT AFT A WEAK S/WV PASSAGE WED NGT WHICH WILL FEATURE SCT FLURRIES ACROSS THE FA...A SOMEWHAT STRONGER CAN CLIPPER S/WV WILL APCH THU AND BRING LGT SNFL TO THE FA THU NGT. THIS SYSTEM WILL BE FOLLOWED BY A SEMI ARCTIC FRONT LATE FRI. SKY...POP AND WX GRIDS WERE REFINED TO INCLUDE THE LATEST MODEL TIMING ON THESE TWO EVENTS...WITH THE BIGGEST CHG INCREASING POPS LATE THU INTO THU EVE INTO THE LIKELY CATEGORY. THERE IS A POSSIBILITY THAT SNFL FROM THIS EVENT WILL BE FLUFFY...WITH FAIRLY HIGH SNOW/LQD EQV RATIOS...BUT ITS A LITTLE ERLY TO SPECIFY THIS DETAIL ACCURATELY ATTM IN THE FCST. AFTERWARDS...THE NEXT SIGNIFICANT S/WV IS SLATED TO AFFECT OUR FA LATE NEXT WEEKEND. MED RANGE MODELS CONT TO SHOW A SPECTRUM OF SOLUTIONS REGARDING THIS SYSTEM. MODIFIED HI/LOW TEMPS IN THE LONGER TERM TO INCLUDE GFS MEAN ENS DATA. USED A BLEND OF 00Z ETA12/GFS80 DATA FOR WINDS FOR PDS 4 THRU 6 AND THEN WENT SPECIFICALLY TO GFS80 DATA TO THE END OF DAY 4 WHERE WINDS WERE DOVE-TAILED INTO HPC WINDS FROM LAST FCST UPDATE. AVIATION... VFR CONDITIONS CAN BE EXPECTED MOST OF THE MORNING. CONDITIONS WILL DETERIORATE TO MVFR AND IFR THIS AFTERNOON DUE TO LOWERING CEILINGS AND VSBYS IN LIGHT SNOW. MARINE... NO HEADLINES EXPECTED IN THE SHORT TERM AND NO SIG HEADLINES ANTICIPATED IN THE LONGER TERM ATTM. CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ UPDATE...HEWITT SHORT TERM/MARINE...DUDA LONG TERM/MARINE...NOUHAN me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 904 AM EST TUE FEB 21 2006 .UPDATE... SHORTWAVE APPARENT ON WATER VAPOR IMAGERY JUST PASSING THROUGH THE SAGINAW VALLEY. 12Z RUC INDICATES GOOD LOW-LEVEL CONVERGENCE ALONG THE COLD FRONT AS IT SWINGS THROUGH SOUTHEAST MICHIGAN THIS MORNING. FORECAST SOUNDINGS SHOW A SOMEWHAT BETTER MOISTURE DEPTH UP TO 8KFT ACROSS THE THUMB...MUCH DRIER AND WITH LOWER INVERSIONS TO THE SOUTH AS SEEN BY 12Z DTX AND 13Z TAMDAR SOUNDINGS. LIFT AND CONVERGENCE HELPING TO INTENSIFY PRECIP ACROSS THE NORTHERN CWA...WITH A DECENT AREA OF >20DBZ RETURNS APPARENT ON THE DTX RADAR AND BAX/CFS REPORTING MVFR VISIBILITY RESTRICTIONS. UPDATED TO ADD SCATTERED SNOW SHOWERS ACROSS THE NORTHEASTERN CWA. REFLECTIVITIES ARE LIGHT ACROSS THE NORTHWESTERN CWA AS THEY ARE ACROSS HURON COUNTY... HOWEVER ONLY MENTIONED FLURRIES FOR THE TRI CITIES AS THE MBS/HYX NORTHWEST WIND INDICATES THE FRONT HAS ALREADY PASSED THROUGH. ALSO EXTENDED FLURRIES SOUTH THROUGH ABOUT I-94 GIVEN ORIENTATION OF CONVERGENCE ALONG THE FRONT...BUT NOT MUCH FARTHER GIVEN THE DEGREE OF DRIER AIR TO THE SOUTH. && .AVIATION...638 AM EST TUE FEB 21 2006 OCCASIONAL MVFR CEILINGS EXPECTED AT ALL TAF SITES THIS MORNING...AND THROUGH THE EARLY PART OF THE AFTERNOON AT KMBS/KFNT...WITH CLOUDS INDUCED BY COMBINATION OF TROUGH LIFT EARLY...AND THIS AFTERNOON FROM LATE WINTER DIURNAL BOOST COMBINED WITH LAKE MI ENHANCED. EXPECT CLOUDS TO BECOME SCATTERED OR FEW LATE AFTERNOON OR EARLY EVENING AS RIDGE AND ASSOCIATED DRYING/SUBSIDENCE DRIFTS OVERHEAD. VFR OVERNIGHT...WITH JUST SOME MID LEVEL WARM ADVECTION CLOUDS ANTICIPATED. FLURRIES MENTIONED AT KMBS/KFNT THIS MORNING...BUT NO VISIBILITY RESTRICTIONS MENTIONED DUE TO WEAK RADAR TRENDS...WEAK DYNAMICS...AND FEEBLE MOISTURE. && .SHORT TERM...TODAY AND TONIGHT...ISSUED 430 AM EST TUE GOOD AGREEMENT AMONG MODELS DEPICTING WEAK SURFACE COLD FRONT/TROUGH MOVING THROUGH AREA THIS MORNING...THEN WEAK RIDGING THIS AFTERNOON INTO TONIGHT...FOLLOWED BY ANOTHER TROUGH APPROACHING LATE TONIGHT. AT 500 MB...NORTHERN LAKES SHORTWAVE TROUGH RETREATING EAST THIS MORNING...WEAK SHORTWAVE RIDGING IN ITS WAKE TODAY...ANOTHER WEAKER TROUGH REACHING NORTHERN LAKES REGION LATE TONIGHT. MODEL QPF FIELDS RATHER MEAGER THROUGH TONIGHT. RUC/GFS/WRFXX SHOW VERY LIGHT PRECIPITATION TODAY MAINLY THIS MORNING...THEN DRY TONIGHT...WHEREAS NAM/NGM DRY THROUGH TONIGHT. RESIDUAL VERY MODEST LOW TO MID LEVEL OMEGA LIFT DEPARTING EARLY THIS MORNING...SLIGHT AGAIN LATE TONIGHT...WHILE QVECTOR CONVERGENCE SLIGHT AT BEST TODAY AND SLIGHT TO MODEST TONIGHT. LOW LEVEL CONVERGENCE WEAK INTO THIS MORNING...SLIGHT AGAIN LATE TONIGHT MAINLY NORTH. 280K ISENTROPIC ASCENT WEAK AT BEST LATE TONIGHT...AS CONDENSATION PRESSURE DEFICITS DO DIP TO 20 TO 30 MB IN THE SAGINAW VALLEY PROXIMITY. RELATIVE HUMIDITY PRETTY LIMITED FOR MEASURABLE SNOW AS WELL. 850 TO 500 MB MOISTURE VERY MEAGER THROUGH TONIGHT...AND LOWER MOISTURE MODESTLY GOOD TODAY BEFORE TRENDING DRIER TONIGHT. WILL FOLLOW IDEA OF PREVIOUS FORECAST...WITH NO PRECIPITATION MENTION STRONGER THAN FLURRIES THROUGH TONIGHT...AND THAT MENTION PRIMARILY NORTH WHERE LOW LEVEL MOISTURE WILL BE AIDED BY LAKE MICHIGAN TRAJECTORIES. GOING A FEW DEGREES WARMER TODAY THAN YESTERDAY...AS 850 MB TEMPERATURES SLOWLY MODERATE. && .LONG TERM...WEDNESDAY THROUGH MONDAY...ISSUED 430 AM EST TUE DURING THE LONG TERM FORECAST...THE STRONG RIDGE THAT HAS BEEN IN PLACE OVER THE GULF OF ALASKA WILL START TO FLATTEN...CAUSING THE NORTHERN STREAM FLOW TO BECOME SLIGHTLY MORE ZONAL THROUGH FRIDAY. BY THIS WEEKEND THE FLOW BUCKLES AGAIN AS A CLOSED UPPER LOW SETS UP OFF THE PACIFIC NORTHWEST COAST...ALLOWING A RIDGE TO BUILD OVER THE WESTERN CONUS WITH A TROUGH SETTING UP OVER THE NORTHEASTERN STATES. TEMPERATURES WILL MODERATE THROUGH THURSDAY...THEN RETURN TO BELOW NORMAL BEHIND A COLD FRONT THAT WILL MOVE ACROSS THE CENTRAL GREAT LAKES ON SATURDAY. THE NEXT WAVE TO IMPACT THE REGION WILL MOVE ACROSS THE NORTHERN GREAT LAKES ON THURSDAY. THE ASSOCIATED SURFACE LOW IS EXPECTED TO TRACK ACROSS LAKE SUPERIOR TO SOUTHERN QUEBEC. THE 00Z/21 GFS IS AN OUTLIER SHOWING THIS LOW TRACKING ACROSS NORTHERN LOWER MICHIGAN AND BRINGING UP TO AN INCH OF SNOW TO THE NORTHERN HALF OF THE CWA. PREFER THE SOLUTION OFFERED UP BY THE MAJORITY OF OTHER MODELS SHOWING A MORE NORTHERN TRACK. A BROAD UPPER LEVEL TROUGH WILL BE SETTING UP OVER MOST OF THE NORTHERN CONUS AT THIS TIME...MAKING IT HARD FOR THIS LOW TO TRACK SOUTHEAST TOWARDS NEW YORK STATE. WILL CONTINUE WITH LOW CHANCE OF SNOW SHOWERS FOR THURSDAY IN THE NORTH WITH A PERIOD OF WEAK LIFT AS THE COLD FRONT SLIDES SOUTH. AM NOT ANY ACCUMULATION AT THIS TIME. SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL HELP TEMPERATURES WARM TO NEAR TO JUST ABOVE NORMAL FOR WEDNESDAY AND THURSDAY. EXACTLY HOW WARM WE GET ON THURSDAY WILL DEPEND ON FRONTAL TIMING BUT WOULD EXPECT THE SOUTHEASTERN CWA TO SEE TEMPS CLIMBING TO JUST ABOVE 40 AHEAD OF THE FRONT. WILL LEAN TOWARDS THE ECMWF FOR THE REMAINDER OF THE FORECAST AS THE GFS NEVER SEEMS TO GET BACK ON TRACK AFTER THE THURSDAY SYSTEM. THE ECMWF IS STILL ABOUT 12 HOURS BEHIND THE GFS FOR THE FRONTAL PASSAGE ON SATURDAY WITH THE REST OF THE MODELS SOMEWHERE IN BETWEEN. HAVE REMOVED PRECIP FOR FRIDAY WITH HIGH PRESSURE EXPECTED OVER THE CENTRAL GREAT LAKES. GOOD ISENTROPIC LIFT MOVES OVER THE AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF THE LOW BRINGING OUR BEST CHANCE FOR SNOW THIS WEEK. GOOD UPPER LEVEL DIVERGENCE WILL ALSO BE OVER THE AREA AND EXPECT TO SEE SOME LIGHT ACCUMULATIONS BY MIDDAY ON SATURDAY. A BLAST OF COLD AIR FILTERS IN OVER THE REGION THIS WEEKEND WITH 850MB TEMPS DROPPING TO -18 TO -20C. TEMPERATURES WILL BE BELOW NORMAL THROUGH THE BEGINNING OF NEXT WEEK WITH HIGHS IN THE LOW TO MID 20S FOR SUNDAY AND MONDAY. SNOW SHOWERS ARE POSSIBLE THROUGH SUNDAY NIGHT WITH COLD CYCLONIC FLOW OVER THE AREA AND THE POTENTIAL FOR SOME LAKE EFFECT SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421-LHZ441..UNTIL NOON TODAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....DWD SHORT TERM...DWD LONG TERM....KAHL 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 DETROIT/PONTIAC MI 638 AM EST TUE FEB 21 2006 .AVIATION... OCCASIONAL MVFR CEILINGS EXPECTED AT ALL TAF SITES THIS MORNING...AND THROUGH THE EARLY PART OF THE AFTERNOON AT KMBS/KFNT...WITH CLOUDS INDUCED BY COMBINATION OF TROUGH LIFT EARLY...AND THIS AFTERNOON FROM LATE WINTER DIURNAL BOOST COMBINED WITH LAKE MI ENHANCED. EXPECT CLOUDS TO BECOME SCATTERED OR FEW LATE AFTERNOON OR EARLY EVENING AS RIDGE AND ASSOCIATED DRYING/SUBSIDENCE DRIFTS OVERHEAD. VFR OVERNIGHT...WITH JUST SOME MID LEVEL WARM ADVECTION CLOUDS ANTICIPATED. FLURRIES MENTIONED AT KMBS/KFNT THIS MORNING...BUT NO VISIBILITY RESTRICTIONS MENTIONED DUE TO WEAK RADAR TRENDS...WEAK DYNAMICS...AND FEEBLE MOISTURE. && .SHORT TERM...TODAY AND TONIGHT...ISSUED 430 AM EST TUE GOOD AGREEMENT AMONG MODELS DEPICTING WEAK SURFACE COLD FRONT/TROUGH MOVING THROUGH AREA THIS MORNING...THEN WEAK RIDGING THIS AFTERNOON INTO TONIGHT...FOLLOWED BY ANOTHER TROUGH APPROACHING LATE TONIGHT. AT 500 MB...NORTHERN LAKES SHORTWAVE TROUGH RETREATING EAST THIS MORNING...WEAK SHORTWAVE RIDGING IN ITS WAKE TODAY...ANOTHER WEAKER TROUGH REACHING NORTHERN LAKES REGION LATE TONIGHT. MODEL QPF FIELDS RATHER MEAGER THROUGH TONIGHT. RUC/GFS/WRFXX SHOW VERY LIGHT PRECIPITATION TODAY MAINLY THIS MORNING...THEN DRY TONIGHT...WHEREAS NAM/NGM DRY THROUGH TONIGHT. RESIDUAL VERY MODEST LOW TO MID LEVEL OMEGA LIFT DEPARTING EARLY THIS MORNING...SLIGHT AGAIN LATE TONIGHT...WHILE QVECTOR CONVERGENCE SLIGHT AT BEST TODAY AND SLIGHT TO MODEST TONIGHT. LOW LEVEL CONVERGENCE WEAK INTO THIS MORNING...SLIGHT AGAIN LATE TONIGHT MAINLY NORTH. 280K ISENTROPIC ASCENT WEAK AT BEST LATE TONIGHT...AS CONDENSATION PRESSURE DEFICITS DO DIP TO 20 TO 30 MB IN THE SAGINAW VALLEY PROXIMITY. RELATIVE HUMIDITY PRETTY LIMITED FOR MEASURABLE SNOW AS WELL. 850 TO 500 MB MOISTURE VERY MEAGER THROUGH TONIGHT...AND LOWER MOISTURE MODESTLY GOOD TODAY BEFORE TRENDING DRIER TONIGHT. WILL FOLLOW IDEA OF PREVIOUS FORECAST...WITH NO PRECIPITATION MENTION STRONGER THAN FLURRIES THROUGH TONIGHT...AND THAT MENTION PRIMARILY NORTH WHERE LOW LEVEL MOISTURE WILL BE AIDED BY LAKE MICHIGAN TRAJECTORIES. GOING A FEW DEGREES WARMER TODAY THAN YESTERDAY...AS 850 MB TEMPERATURES SLOWLY MODERATE. && .LONG TERM...WEDNESDAY THROUGH MONDAY...ISSUED 430 AM EST TUE DURING THE LONG TERM FORECAST...THE STRONG RIDGE THAT HAS BEEN IN PLACE OVER THE GULF OF ALASKA WILL START TO FLATTEN...CAUSING THE NORTHERN STREAM FLOW TO BECOME SLIGHTLY MORE ZONAL THROUGH FRIDAY. BY THIS WEEKEND THE FLOW BUCKLES AGAIN AS A CLOSED UPPER LOW SETS UP OFF THE PACIFIC NORTHWEST COAST...ALLOWING A RIDGE TO BUILD OVER THE WESTERN CONUS WITH A TROUGH SETTING UP OVER THE NORTHEASTERN STATES. TEMPERATURES WILL MODERATE THROUGH THURSDAY...THEN RETURN TO BELOW NORMAL BEHIND A COLD FRONT THAT WILL MOVE ACROSS THE CENTRAL GREAT LAKES ON SATURDAY. THE NEXT WAVE TO IMPACT THE REGION WILL MOVE ACROSS THE NORTHERN GREAT LAKES ON THURSDAY. THE ASSOCIATED SURFACE LOW IS EXPECTED TO TRACK ACROSS LAKE SUPERIOR TO SOUTHERN QUEBEC. THE 00Z/21 GFS IS AN OUTLIER SHOWING THIS LOW TRACKING ACROSS NORTHERN LOWER MICHIGAN AND BRINGING UP TO AN INCH OF SNOW TO THE NORTHERN HALF OF THE CWA. PREFER THE SOLUTION OFFERED UP BY THE MAJORITY OF OTHER MODELS SHOWING A MORE NORTHERN TRACK. A BROAD UPPER LEVEL TROUGH WILL BE SETTING UP OVER MOST OF THE NORTHERN CONUS AT THIS TIME...MAKING IT HARD FOR THIS LOW TO TRACK SOUTHEAST TOWARDS NEW YORK STATE. WILL CONTINUE WITH LOW CHANCE OF SNOW SHOWERS FOR THURSDAY IN THE NORTH WITH A PERIOD OF WEAK LIFT AS THE COLD FRONT SLIDES SOUTH. AM NOT ANY ACCUMULATION AT THIS TIME. SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL HELP TEMPERATURES WARM TO NEAR TO JUST ABOVE NORMAL FOR WEDNESDAY AND THURSDAY. EXACTLY HOW WARM WE GET ON THURSDAY WILL DEPEND ON FRONTAL TIMING BUT WOULD EXPECT THE SOUTHEASTERN CWA TO SEE TEMPS CLIMBING TO JUST ABOVE 40 AHEAD OF THE FRONT. WILL LEAN TOWARDS THE ECMWF FOR THE REMAINDER OF THE FORECAST AS THE GFS NEVER SEEMS TO GET BACK ON TRACK AFTER THE THURSDAY SYSTEM. THE ECMWF IS STILL ABOUT 12 HOURS BEHIND THE GFS FOR THE FRONTAL PASSAGE ON SATURDAY WITH THE REST OF THE MODELS SOMEWHERE IN BETWEEN. HAVE REMOVED PRECIP FOR FRIDAY WITH HIGH PRESSURE EXPECTED OVER THE CENTRAL GREAT LAKES. GOOD ISENTROPIC LIFT MOVES OVER THE AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF THE LOW BRINGING OUR BEST CHANCE FOR SNOW THIS WEEK. GOOD UPPER LEVEL DIVERGENCE WILL ALSO BE OVER THE AREA AND EXPECT TO SEE SOME LIGHT ACCUMULATIONS BY MIDDAY ON SATURDAY. A BLAST OF COLD AIR FILTERS IN OVER THE REGION THIS WEEKEND WITH 850MB TEMPS DROPPING TO -18 TO -20C. TEMPERATURES WILL BE BELOW NORMAL THROUGH THE BEGINNING OF NEXT WEEK WITH HIGHS IN THE LOW TO MID 20S FOR SUNDAY AND MONDAY. SNOW SHOWERS ARE POSSIBLE THROUGH SUNDAY NIGHT WITH COLD CYCLONIC FLOW OVER THE AREA AND THE POTENTIAL FOR SOME LAKE EFFECT SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421-LHZ441..UNTIL NOON TODAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...DWD SHORT TERM...DWD LONG TERM....KAHL YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 953 AM EST TUE FEB 21 2006 .SHORT TERM...FAST ZONAL FLOW CONTINUES WITH WEAK DISTURBANCES MOVING ACROSS THE REGION. SHORTWAVE SHOULD MOVE OFFSHORE SHORTLY AND TAKE LIGHT RAINFALL WITH IT. RUC SHOWING CLEARING DURING THE AFTERNOON WHICH MATCHES WELL WITH CURRENT SATELLITE DEPICTION. WILL MAKE MINOR ADJUSTMENT TO CURRENT FCST TO REMOVE MORNING WORDING...OTHERWISE AFTERNOON TEMP FCST LOOKS FINE. && .AVIATION...IMPROVING CONDITIONS FROM WEST TO EAST THIS MORNING. STILL DEALING WITH SOME IFR CONDITIONS OVER MUCH OF THE TWEB ROUTE. CIGS AT KPGV AND KISO HAVE COME UP TO MVFR DURING THE PAST HOUR. THIS TREND WILL CONTINUE WITH ALL TERMINALS MVFR BY 16Z. VFR CONDITIONS EXPECTED AFTER 18Z WITH SCT CLOUDS BETWEEN 3-5K FT LINGERING THOUGH EARLY AFTERNOON. && .MARINE...MADE ONLY COSMETIC CHANGES TO CURRENT GRIDS. FORECAST REMAINS ON TRACK WITH TRANQUIL BOATING CONDITIONS CONTINUING OVER ALL COASTAL WATERS THROUGH THIS EVENING. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SHORT TERM...COLLINS AVIATION...WINGENROTH MARINE...WINGENROTH nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 901 AM CST TUE FEB 21 2006 .UPDATE... FAIRLY STRONG SHORTWAVE CONTINUES TO MOVE SOUTHEAST INTO NW ND...AND ASSOCIATED LIFT AND SNOW BAND IS DEVELOPING ON SCHEDULE. THE TRACK OF VORTICITY MAX AND 700MB TROUGH WILL COME ACROSS THE AREA THIS AFTERNOON...AND SHOULD TARGET THE NORTHERN 2/3 OF THE AREA WITH THE BEST CHANCE AT ACCUMULATING SNOW. MOST AREAS WILL SEE SOME ACCUMULATION...AND WILL BE INCREASING POPS INTO CATEGORICAL REALMS ACROSS NORTHERN AREAS AT LEAST. SATURATION IS TAKING SOME TIME THOUGH...WITH SFC DEWPOINTS STILL LOW OVER THE AREA. DEWPOINTS IN CENTRAL ND ARE IN THE TEENS THOUGH...AND AS THEY ADVECT OVER COOL AIRMASS LIFT WILL BE ENHANCED ACROSS THE AREA. RUC PICKS THIS SCENARIO UP THE BEST WITHIN THE FIRST 12 HOURS...AND WILL USE IT/S QPF FOR SNOW AMOUNTS. THEREFORE FEEL FAIRLY CONFIDENT OF SEEING FAIRLY WIDESPREAD LIGHT SNOW BY AFTERNOON...WITH AN INCH...POSSIBLY 2 IN LOCALIZED AREAS IF SOME BANDING CAN OCCUR... WHICH IS POSSIBLE. WILL BE WATCHING SNOW BAND FOR THE NEXT HOUR...AND INCREASE POPS ACROSS AT LEAST NORTHERN AREAS. TEMPS LOOK TO BE ON TARGET...AND ONLY MINIMAL CHANGES NEEDED HERE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ DK nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 945 AM EST TUE FEB 21 2006 .SYNOPSIS... VERY PROGRESSIVE...SPLIT MID-UPPER LEVEL FLOW PERSISTS ACROSS THE U.S. EAST OF THE ROCKIES TODAY. FOR THE NORTH COUNTRY...A FAST-MOVING SHORTWAVE TROUGH EVIDENT ON WV IMAGERY NEAR GEORGIAN BAY AT 14Z IS EXPECTED TO CONTINUE EWD...REACHING THE GULF OF MAINE BY 22/00Z. && .SHORT TERM /REST OF TODAY/... MODERATE DEEP-LAYER PVA/Q-VECTOR CONVERGENCE THROUGH MID-AFTERNOON WILL BRING GENERALLY OVC CONDITIONS TO THE FORECAST AREA...BUT ONLY SCATTERED SNOW SHOWERS...MOSTLY ASSOCIATED WITH ENHANCEMENT FROM LAKE ONTARIO AND/OR OROGRAPHIC LIFT. THE 12Z ALB SOUNDING INDICATES THAT MOISTURE IS LIMITED WITH THIS SYSTEM...AND GOING FORECAST OF CHANCE OF LIGHT SNOW SHOWERS LOOKS ON TARGET. UPSLOPE ENHANCEMENT IN ADIRONDACKS AND GREEN MTNS WILL RESULT IN LIKELY -SHSN TODAY...WITH A DUSTING TO 2 INCHES OF SNOW ACCUMULATION IN THE GREENS AND 1-3 INCHES IN THE NRN ADIRONDACKS. SYNOPTIC ENHANCEMENT TO LAKE EFFECT BAND OFF LAKE ONTARIO WILL CONTINUE TO IMPACT ST. LAWRENCE COUNTY OVER THE NEXT FEW HOURS. AS LOW-TO-MID LEVEL FLOW VEERS WITH PASSAGE OF SHORTWAVE TROUGH...LAKE BAND SHOULD MIGRATE SOUTH OF THE FORECAST AREA. TIMING IN LATEST NAM/RUC FORECASTS SUGGESTS THIS SHOULD OCCUR BETWEEN 18Z AND 19Z. INFLUENCE OF LAKE MOISTURE AND MARGINAL INSTABILITY WILL RESULT IN ISOLATED/LOCALIZED HIGHER AMTS OF SNOW ACROSS SRN ST. LAWRENCE COUNTY...PERHAPS UP TO 4 INCHES. OVERALL WX...WINDS...TEMPS LOOK WELL-HANDLED BOTH IN THE GRIDS AND ZFP. BASED ON SATELLITE TRENDS...WILL UPDATE THIS MORNING ONLY TO INCREASE SKY COVER TO CLOUDY FROM MOSTLY CLOUDY ACROSS NWRN 2/3RDS OF FORECAST AREA. && .PREV DISCUSSION... /ISSUED 245 AM EST TUE FEB 21 2006/ SYNOPSIS... MID/UPPER LVL TROF CONTS ACRS THE EASTERN THIRD OF THE CONUS WITH SEVERAL EMBEDDED 5H VORTS. FIRST VORT NOW LOCATED ACRS THE WESTERN GREAT LAKES WL IMPACT FA TODAY WITH ANOTHER VORT OVER CENTRAL CANADA EXPECTED TO MV ACRS CWA ON THURSDAY. FIRST...PIECE OF ENERGY HAS LIMITED MOISTURE AND WL QUICKLY MOVE ACRS OUR FA TODAY. THE SUB-TROPICAL JET CONTS TO BE SUPPRESSED ACRS THE SOUTHERN STATES WITH NO INTERACTION WITH NORTHERN STREAM ENERGY DUE TO CONFLUENT FLOW ALOFT AND LIMITED AMPLIFICATION OF JET STREAM ENERGY. CRNT RADAR CONTS TO SHOW WEAK BAND OF LES ACRS SOUTHERN ST LAWRENCE AND FRANKLIN COUNTIES ATTM WITH SLOW MOVEMENT TO THE NORTH. SOME LAKE ERIC INTERACTION IS HELPING TO ENHANCE RADAR RETURNS...BUT BASED ON SFC OBS AND WEB CAMS LIMITED REDUCTION IN VIS IS NOTED AND ONLY MINOR SNOW ACCUMULATION HAS BEEN OBSERVED. THIS COMBINED WITH INCREASED LLVL SHEAR AHEAD OF NEXT S/W AND SOME LLVL WAA WL LET LAKE SNOW ADVISORY EXPIRE WITH THIS PACKAGE. SHORT TERM /TODAY THROUGH THURSDAY NIGHT/... TODAY...FIRST IN A SERIES OF WEAK CLIPPER LIKE SYSTEMS MOVES ACRS OUR FA. THE COMBINATION OF 850-500MB Q-VECTOR CONVERGENCE FROM STRONG PVA AND FAVORABLE SW UPSLOPE FLW ACRS THE DACKS WITH SOME LAKE MOISTURE INTERACTION WL MENTION LIKELY POPS WESTERN CWA. IN ADDITION...WL MENTION LIKELY POPS THIS AFTN FOR THE WESTERN SLOPES OF THE GREEN MTNS AS WINDS BCM NW BEHIND SFC FRNT...EXPECT SOME UPSLOPE ENHANCEMENT. WL MENTION 1-3 INCHES FOR DACKS AND 1-2 INCHES FOR THE GREENS. OTHERWISE...PROGGED 85H TEMPS ARE 1 TO 2 DEGREES WARMER THAN YESTERDAY...SO EXPECT HIGHS IN THE L30S VALLEYS TO MID 20S IN THE MTNS. TONIGHT...WEAK UPSLOPE FLW CONT UNTIL 06Z ACRS WESTERN SLOPES OF THE GREENS...THEN DEPTH OF MOISTURE DECREASES. WL MENTION LIKELY POPS EARLY WITH CHC POPS AFT MIDNIGHT...SOME LIGHT ACCUMULATION WL BE POSSIBLE. WEDS...WEAK SFC RIDGE BUILDS INTO FA AND LLVL WAA DEVELOPS BY EARLY AFTN. PROGGED 85H TEMPS NEAR -12C SUPPORT HIGHS IN THE 30S MOST LOCATIONS TO U20S IN THE MTNS. WL KEEP VALLEYS DRY...BUT WL BE SLIGHT TO CHC POPS IN THE MTNS BASED ON LLVL MOISTURE AND STEEP 1000-850MB LAPSE RATES. WEDS NIGHT-THURS...MODELS IN GOOD AGREEMENT WITH TAKING NEXT CLIPPER SYSTEM ACRS OUR FA LATE WEDS INTO THURS. THIS SYSTEM BASED ON VAPOR TRENDS HAS A BIT MORE MOISTURE TO WORK WITH AND BETTER LIFT ASSOCIATED WITH STRONG JET AND SFC CONVERGENCE. BASED ON RIBBON OF 850-500MB OMEGA...GOOD DEEP LAYER MOISTURE BTWN 1000-500MB...AND FAVORABLE MOISTURE/OMEGA SNOW GROWTH POTENTIAL WL MENTION LIKELY POPS MOST LOCATIONS. HOWEVER...WL TRIM POPS TO CHC ACRS CPV AND SOUTHERN VT. PROGGED 85H TEMPS NEAR -10C AND 925MB TEMPS NEAR -2C SUPPORT HIGHS IN THE 30S. LONG TERM /FRIDAY THROUGH MONDAY/... SECONDARY COLD FRONT PUSHES ACRS OUR FA ON FRIDAY WITH TEMPS STRUGGLING IN THE 20S BASED ON NORTHERLY FLW AND PROGGED 85H TEMPS AROUND -15C. WL MENTION CHC POPS...ESPECIALLY ACRS THE MTNS ZNS BASED ON NW UPSLOPE FLW...BUT DEPTH OF MOISTURE WL BE LIMITED. HIGH PRES AXIS QUICKLY SHIFT ACRS OUR FA ON FRIDAY NIGHT WITH LLVL WAA DEVELOPING ON SATURDAY AHEAD OF OUR NEXT CLIPPER SYSTEM. WL INCREASE CLOUDS FROM WEST TO EAST...ALONG WITH POPS ASSOCIATED WITH THIS SYSTEM FOR SATURDAY. MUCH COLD AIR IS EXPECTED FOR SUNDAY INTO MONDAY WITH TEMPS IN THE TEENS/20S AND OVERNIGHT LOWS NEAR 0F. AVIATION... A LOW PRESSURE AREA NORTH OF THE GREAT LAKES EARLY THIS MORNING WILL MOVE EAST AND BE OVER SOUTHERN QUEBEC THIS AFTERNOON. AN UPPER SHORTWAVE ASSOCIATED WITH THIS LOW PRESSURE AREA WILL MOVE EAST FROM THE GREAT LAKES EARLY THIS MORNING...AND MOVE ACROSS THE REGION EARLY THIS AFTERNOON. COMPOSITE RADAR LOOP EARLY THIS MORNING SHOW LAKE EFFECT SNOW SHOWERS FROM EASTERN LAKE ONTARIO ACROSS THE SOUTHERN SAINT LAWRENCE VALLEY AND THE ADIRONDACKS EARLY THIS MORNING. THE UPPER SHORTWAVE MOVING EAST FROM THE WESTERN GREAT LAKES EARLY THIS MORNING WILL ENHANCE THE LAKE EFFECT SNOW SHOWER ACTIVITY FROM LAKE ONTARIO WITH IFR/MVFR CEILINGS AND VISIBILITIES BECOMING MORE WIDESPREAD ACROSS THE SAINT LAWRENCE VALLEY IN NORTHERN NEW YORK AND THE ADIRONDACKS. RADAR ALSO SHOWING SOME SCATTERED SNOW SHOWER ACTIVITY DEVELOPING ALONG THE WESTERN SLOPES OF THE NORTHERN GREEN MOUNTAINS AT THIS TIME. THE HIGHER TERRAIN OF THE ADIRONDACKS AND NORTHERN GREEN MOUNTAINS WILL BE OBSCURED IN CLOUDS AND PRECIPITATION TODAY AND TONIGHT. EXPECTING MAINLY...VFR CONDITIONS TODAY ACROSS THE CHAMPLAIN VALLEY AND ACROSS THE REMAINDER OF VERMONT TODAY AND TONIGHT. SOME POCKETS OF MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE ACROSS THE NORTHERN GREEN MOUNTAINS TODAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SHORT TERM...BANACOS vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 302 PM CST TUE FEB 21 2006 .SYNOPSIS...SURFACE BOUNDARY OVER THE GULF BEYOND THE COASTAL WATERS IS NOW RETREATING NORTHWARD AS A WARM FRONT AND IS BECOMING LESS DISTINCT ON THE VISIBLE IMAGERY. WEDGE OF COOL AIR AHEAD OF THIS FRONT CONTINUES TO THIN OUT WITH HOLES APPEARING WHERE SUN IS BREAKING THROUGH. EXPECT THIS WARM FRONT TO REACH THE COAST THIS EVENING PER LATEST RUC. ALONG WITH A BRIEF WARMING TREND, RAIN RETURNS TO THE FORECAST ON WEDNESDAY THANKS TO A MOISTURE BUILDUP FROM THE PACIFIC COURTESY OF A STRENGHENING SUBTROPICAL JET. THIS MOISTURE WILL ENCOUNTER LIFT AHEAD OF THE NEXT CANADIAN COLD FRONT WHICH IS EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT. ZONAL FLOW OFF THE PACIFIC WILL BRING A STALL TO THIS FRONT IN THE NORTHERN GULF...SETTING UP ANOTHER OVERRUNNING REGIME WITH LIGHT RAIN AND COOL TEMPS OVER THE LATTER PORTION OF THE WEEK. WE MAY BE FORTUNATE ENOUGH TO SEE SOME SUN LATE THIS WEEKEND DEPENDING ON HOW FAR SOUTH THE FRONTAL BOUNDARY GETS DRIVEN DUE TO A SURGE OF SURFACE HIGH PRESSURE AND NORTHWESTERLY FLOW AT THE MID LEVELS, HOWEVER CONFIDENCE NOT HIGH AS THE UPPER FLOW OFF THE PACIFIC IS SPLIT. WENT WITH THE GFS WHICH SHOWS MOST OF THE PACIFIC ENERGY RIDING NORTH OF THE WESTERN RIDGE AND INTO THE DIGGING TROF ALONG THE EAST COAST. TEMPS SHOULD REMAIN ON THE COOL SIDE. && .DISCUSSION...DECIDED TO BACK OFF ON ISSUING A DENSE FOG ADVISORY DUE TO SEA FOG. THE SHELF WATER TEMPS HAVE RECOVERED TO THE UPPER 50S. RECENT EXPERIENCE HAS SHOWN THAT MID 50 WATER TEMPS ARE MORE CONDUCIVE FOR SEA FOG. ALSO REMOVED MENTION OF PRECIP TNITE DUE TO CAPPING AND NVA. WENT HIGHER ON TEMPS WITH THE WARMUP ON WEDNESDAY DESPITE THE CLOUDCOVER FROM THE INCREASING MOISTURE. H85 TEMPS HAVE ALREADY STARTED A RUNUP DESPITE THE SHALLOW COLD AIRMASS BELOW. 12 TO 15C TEMPS AT H85 WITH 76F WATER TEMPS FURTHER OUT IN THE GULF COULD ALLOW TEMPS TO SOAR WELL INTO THE 70S FOR THE SOUTHERN ZONES...UPPER 60S TO THE NORTH...A WELCOME CHANGE. DUE TO THE SLOWER TIMING ON THE NEXT FRONT...KEPT A BIT WARMER THAN GUIDANCE THROUGH WED NIGHT. && .AVIATION...STILL EXPECTING DETERIORATING CIGS AND VIS DOWN TO LIFR BY SUNRISE IN ADVANCE OF THE WARM FRONT. && .MARINE...WILL GO WITH JUST PATCHY FOG OVER THE COASTAL WATERS. && .PRELIMINARY POINT TEMPS/POPS... KLCH 59 76 60 65 / 0 40 40 40 KBPT 59 77 60 65 / 0 40 40 30 KAEX 53 67 52 53 / 0 50 50 50 KLFT 59 78 61 64 / 0 40 40 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. && $$ 11 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 402 PM EST TUE FEB 21 2006 .SHORT TERM...TONIGHT AND WEDNESDAY 12Z RAOBS/WATER VAPOR LOOP SHOW A BRIEF SHORTWAVE RIDGE OVER THE WESTERN GREAT LAKES...BETWEEN SHORTWAVES DOWNSTREAM OVER SOUTHEAST ONTARIO AND UPSTREAM JUST SOUTHWEST OF LAKE WINNIPEG. SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM THE GREAT LAKES TO THE GULF COAST...WITH THE RIDGE AXIS JUST CROSSING LAKE MICHIGAN. UPSTREAM LOW/TROUGH OVER NORTH DAKOTA. VIS SATELLITE SHOW CU HAS MIXED OUT ACROSS THE SOUTHERN CWA...WITH VFR CLOUDS MAINTAINING ACROSS THE NORTHERN CWA DUE TO A COMBINATION OF LAKE MOISTURE AND BETTER INSTABILITY UNDER THE CORE OF THE THERMAL TROUGH. NAM/GFS HAVE BOTH TRENDED A LITTLE SLOWER WITH THE NEXT CLIPPER CURRENTLY NEAR LAKE WINNIPEG...AND HAVE ALSO TRENDED WEAKER OVER THE LAST COUPLE RUNS. HOWEVER THE 15Z/18Z RUC INITIALIZATIONS ARE STRONGER/MORE COMPACT...WHICH LOOK MORE IN LINE WITH WATER VAPOR IMAGERY. WHILE SYNOPTIC SUPPORT IS WEAK TO MODERATE...MOISTURE REMAINS PRETTY MARGINAL...LIMITED BY DRY AIR NEAR THE SURFACE ESPECIALLY FARTHER SOUTH AWAY FROM THE SYSTEM. HOWEVER THE OVERALL SETUP LOOKS SOMEWHAT SIMILAR TO THE SYSTEM THAT SWEPT THROUGH THE CWA THIS MORNING. A MODEST AREA OF SNOW DEVELOPED IN GOOD LOW-LEVEL CONVERGENCE ALONG THE SURFACE FRONT...WHICH LOOKS REASONABLE AGAIN FOR WEDNESDAY...ENOUGH TO ADD A CHANCE OF SNOW TO THE NORTHERN CWA...WITH FLURRIES TO THE SOUTH. DRY ENOUGH I-94 SOUTH TO KEEP DRY CONDITIONS AND PARTLY SUNNY SKIES. FRONTAL TIMING LOOKS TO BE CLOSER TO 18Z...SO WILL CARRY PRECIP THROUGH THE DAY WITHOUT TRYING TO ADD A MORNING OR AFTERNOON TIMING. WITH THE SLOWER TREND WILL ALSO REMOVE MENTION OF FLURRIES FROM THE TONIGHT PERIOD. AS FOR TEMPERATURES...LOWS LAST NIGHT WERE IN THE LOW/MID 20S. SOUTHERLY GRADIENT PICKS UP OVERNIGHT AFTER THE SURFACE RIDGE AXIS SWINGS THROUGH LOWER MICHIGAN THIS EVENING...LIMITING THE DURATION OF GOOD RADIATIONAL COOLING. THEREFORE INCREASED LOWS A COUPLE DEGREES...SIMILAR TO THAT WHICH OCCURRED LAST NIGHT. ALSO CARRIES LOWS DURING THE EVENING...WITH TEMPS PRETTY STEADY OVERNIGHT WITH THE INCREASING SOUTHERLY FLOW. && .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY THIS PERIOD WILL BE MARKED BY A BRIEF WARMUP PRIOR TO THE RETURN OF VERY COLD ARCTIC AIR. A RESPECTABLE NORTHERN STREAM SYSTEM WILL SINK SOUTHEAST ACROSS THE AREA TO START THE WEEKEND...USHERING IN A PATTERN SHIFT. THE UPPER LEVEL PATTERN WILL BECOME MUCH MORE AMPLIFIED...RIDGE BUILDING OVER THE WESTERN CONUS AND TROUGH DIGGING OVER THE EASTERN CONUS. THIS WILL PLACE US IN A COLD NORTHWEST FLOW SUNDAY THROUGH TUESDAY...WITH TEMPERATURES WELL BELOW NORMAL. PREDOMINATELY ZONAL FLOW THROUGH FRIDAY WILL BRING SEVERAL FAST MOVING NORTHERN STREAM WAVES ACROSS THE GREAT LAKES. THE GFS HAS FINALLY TRENDED A LITTLE FURTHER NORTH TO BE MORE IN LINE WITH WHAT THE MODEL CONSENSUS HAS BEEN OVER THE PAST SEVERAL RUNS. GIVEN THE LATEST GFS TREND TOWARD A MORE NORTHERLY TRACK (ACROSS THE U.P.)...WE WILL LEND MORE CREDIT TO THE NAM WHICH HAS BEEN CONSISTENT WITH A TRACK ACROSS NORTHERN LAKE SUPERIOR...WHICH LOOKS GOOD CONSIDERING THE FAST ZONAL FLOW IN PLACE. AS A RESULT...THE NAM IS WEAKER WITH THE COLD FRONT THROUGH OUR AREA ON THURSDAY. THE ASSOCIATED LIFT WILL LIKELY NOT BE STRONG ENOUGH TO PRODUCE MUCH PRECIP WITH A LIMITED AMOUNT OF MOISTURE TO WORK WITH. WEAK RIDGING AND ASSOCIATED SUBSIDENCE WILL KEEP US DRY WEDNESDAY NIGHT. AND ALTHOUGH THE NAM KEEPS US DRY WITH THE PASSAGE OF THE COLD FRONT ON THURSDAY...WE WILL CONTINUE TO CARRY CHANCE POPS TO ACCOUNT FOR WEAK CONVERGENCE ALONG THE TROUGH AXIS (COLD FRONT.) BREEZY CONDITIONS WILL ACCOMPANY THE FRONT ON THURSDAY...WITH TIGHTENING GRADIENT AND WELL MIXED BOUNDARY LAYER. DRY NORTHWESTERLY FLOW WILL FILTER IN THURSDAY NIGHT INTO FRIDAY AS SURFACE HIGH PRESSURE WORKS EAST ACROSS THE OHIO VALLEY. COLDER AIR FILTERING OVER THE LAKES (850 TEMPS DROPPING TO AROUND -14C) WILL KEEP US MOSTLY CLOUDY AT LEAST FOR THE FIRST HALF OF THURSDAY NIGHT (STRATOCU DECK.) MOISTURE ABOVE 850 WILL STRIP OFF TO THE EAST AS WAVE DEPARTS. THE ANTICYLONIC FLOW AND LACK OF DEEP LAYER MOISTURE SHOULD BE ENOUGH TO KEEP LAKE EFFECT SNOW SHOWERS AT BAY...WHICH IS IN LINE WITH THE WEAKER COLD AIR ADVECTION OFFERED BY THE NAM (GFS 850 TEMPS ARE CLOSER TO -16C.) SUBSIDENCE/DRYING WILL CONTINUE TO DRY US OUT AND BRING PARTLY SUNNY SKIES ON FRIDAY. THERE ARE STILL SOME TIMING AND STRENGTH DIFFERENCES ON THE FRIDAY NIGHT/SATURDAY WAVE...HOWEVER THE GENERAL CONSENSUS TAKES THE LOW ACROSS SOUTHEAST MICHIGAN. GOOD WARM AIR ADVECTION (850 TEMPS RISING TO NEAR 0C NEAR THE OHIO BORDER BY SATURDAY MORNING) AND ASSOCIATED ISENTROPIC LIFT WILL BE GOOD ENOUGH FOR A SHOT OF SNOW FRIDAY NIGHT. A STRONG DRY SLOT WILL WRAP INTO SOUTHEAST MICHIGAN ON SATURDAY. THIS WILL HELP TO CUT BACK ON SNOWFALL TOTALS...ALTHOUGH THE LIFT FRIDAY NIGHT SHOULD BE ENOUGH FOR THE CWA TO GET AN INCH OR TWO OF NEW SNOW BEFORE THE DRY SLOT WORKS IN ON SATURDAY. THIS SYSTEM WILL ALSO KICK UP THE WINDS AND MAKE FOR A BREEZY SATURDAY AFTERNOON AS STRONG COLD AIR ADVECTION GETS UNDER WAY IN TRANSITIONING UPPER LEVEL PATTERN. THERE IS SOME DISAGREEMENT ON THE AMOUNT OF UPPER LEVEL RIDGING ACROSS THE WESTERN CONUS WITH THE MODELS GOING BACK AND FORTH BETWEEN HIGHLY AMPLIFIED AND MORE FLAT. EVEN WITH THIS DIFFERENCE...THE MODELS CONTINUE TO KEEP THE TROUGH OVER THE EASTERN CONUS AMPLIFIED ENOUGH FOR ARCTIC AIR TO RETURN. THIS GIVES US PLENTY OF CONFIDENCE ON A COLD SUNDAY THROUGH TUESDAY...AS 850 TEMPS CRASH TO -20C. THIS AMOUNT OF COLD AIR ADVECTION WILL BE ENOUGH FOR A CHANCE OF LAKE EFFECT SNOW SHOWERS THROUGH MONDAY. ONE INTERESTING NOTE FOR MONDAY...THE 12Z GFS HAS NOW...FOR THE FIRST TIME...INTRODUCED A WAVE DROPPING SOUTH INTO MICHIGAN. THIS IS NOT SURPRISING GIVEN THE COLD NORTHWEST FLOW AND STRONG AMPLIFICATION OF UPPER LEVEL PATTERN. GIVEN THAT THIS IS THE FIRST AND ONLY INDICATION (NO OTHER MODEL SUPPORTS THIS AS OF YET) WE WILL KEEP FORECAST AS IS FOR NOW. && .AVIATION...ISSUED AT 1235 PM EST SURFACE RIDGE OVER THE WESTERN GREAT LAKES WILL BUILD ACROSS LOWER MICHIGAN THIS EVENING...AHEAD OF THE NEXT FRONTAL SYSTEM FOR WEDNESDAY. SOLID MVFR CIGS ALONG THE DEPARTING FRONT HAVE GIVEN WAY TO MORE DIURNALLY ENHANCED VFR CLOUDS. GIVEN THE COVERAGE OF CU UNDER THE LOW-LEVEL THERMAL TROUGH...ESPECIALLY ACROSS THE NORTHWESTERN CWA WITH ADDITIONAL MOISTURE FLUX FROM LAKE MICHIGAN... WILL CARRY BROKEN CIGS THROUGH THE AFTERNOON. CLOUDS ACROSS FAR SOUTHERN LOWER ARE ALREADY BEGINNING TO MIX OUT IN AN AREA OF DIVERGENCE BEHIND THE SURFACE TROUGH. THIS AREA MAY BRIEFLY FILL BACK IN...BEFORE THE MOISTURE MIXES OUT ALL TOGETHER BY MID-LATE AFTERNOON. NEXT SHORTWAVE JUST SOUTHWEST OF LAKE WINNIPEG IS ON TRACK TO SWING THROUGH ON WEDNESDAY. DECENT AREA OF MID CLOUDS EXTENDS OUT AHEAD OF THIS FEATURE ACROSS THE DAKOTAS/MINNESOTA AND INTO WESTERN WISCONSIN. CROSS SECTIONS/PLAN VIEWS AGAIN SHOW BETTER MOISTURE ACROSS THE NORTHERN CWA. HOWEVER FORECAST SOUNDINGS AND UPSTREAM OBSERVATIONS SUPPORT KEEPING CIGS VFR AT ALL TAF SITES. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BRAVENDER LONG TERM....SHULER AVIATION...BRAVENDER 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 DETROIT/PONTIAC MI 1235 PM EST TUE FEB 21 2006 .AVIATION... SURFACE RIDGE OVER THE WESTERN GREAT LAKES WILL BUILD ACROSS LOWER MICHIGAN THIS EVENING...AHEAD OF THE NEXT FRONTAL SYSTEM FOR WEDNESDAY. SOLID MVFR CIGS ALONG THE DEPARTING FRONT HAVE GIVEN WAY TO MORE DIURNALLY ENHANCED VFR CLOUDS. GIVEN THE COVERAGE OF CU UNDER THE LOW-LEVEL THERMAL TROUGH...ESPECIALLY ACROSS THE NORTHWESTERN CWA WITH ADDITIONAL MOISTURE FLUX FROM LAKE MICHIGAN... WILL CARRY BROKEN CIGS THROUGH THE AFTERNOON. CLOUDS ACROSS FAR SOUTHERN LOWER ARE ALREADY BEGINNING TO MIX OUT IN AN AREA OF DIVERGENCE BEHIND THE SURFACE TROUGH. THIS AREA MAY BRIEFLY FILL BACK IN...BEFORE THE MOISTURE MIXES OUT ALL TOGETHER BY MID-LATE AFTERNOON. NEXT SHORTWAVE JUST SOUTHWEST OF LAKE WINNIPEG IS ON TRACK TO SWING THROUGH ON WEDNESDAY. DECENT AREA OF MID CLOUDS EXTENDS OUT AHEAD OF THIS FEATURE ACROSS THE DAKOTAS/MINNESOTA AND INTO WESTERN WISCONSIN. CROSS SECTIONS/PLAN VIEWS AGAIN SHOW BETTER MOISTURE ACROSS THE NORTHERN CWA. HOWEVER FORECAST SOUNDINGS AND UPSTREAM OBSERVATIONS SUPPORT KEEPING CIGS VFR AT ALL TAF SITES. && .UPDATE...904 AM EST TUE FEB 21 2006 SHORTWAVE APPARENT ON WATER VAPOR IMAGERY JUST PASSING THROUGH THE SAGINAW VALLEY. 12Z RUC INDICATES GOOD LOW-LEVEL CONVERGENCE ALONG THE COLD FRONT AS IT SWINGS THROUGH SOUTHEAST MICHIGAN THIS MORNING. FORECAST SOUNDINGS SHOW A SOMEWHAT BETTER MOISTURE DEPTH UP TO 8KFT ACROSS THE THUMB...MUCH DRIER AND WITH LOWER INVERSIONS TO THE SOUTH AS SEEN BY 12Z DTX AND 13Z TAMDAR SOUNDINGS. LIFT AND CONVERGENCE HELPING TO INTENSIFY PRECIP ACROSS THE NORTHERN CWA...WITH A DECENT AREA OF >20DBZ RETURNS APPARENT ON THE DTX RADAR AND BAX/CFS REPORTING MVFR VISIBILITY RESTRICTIONS. UPDATED TO ADD SCATTERED SNOW SHOWERS ACROSS THE NORTHEASTERN CWA. REFLECTIVITIES ARE LIGHT ACROSS THE NORTHWESTERN CWA AS THEY ARE ACROSS HURON COUNTY... HOWEVER ONLY MENTIONED FLURRIES FOR THE TRI CITIES AS THE MBS/HYX NORTHWEST WIND INDICATES THE FRONT HAS ALREADY PASSED THROUGH. ALSO EXTENDED FLURRIES SOUTH THROUGH ABOUT I-94 GIVEN ORIENTATION OF CONVERGENCE ALONG THE FRONT...BUT NOT MUCH FARTHER GIVEN THE DEGREE OF DRIER AIR TO THE SOUTH. && .SHORT TERM...TODAY AND TONIGHT...ISSUED 430 AM EST TUE GOOD AGREEMENT AMONG MODELS DEPICTING WEAK SURFACE COLD FRONT/TROUGH MOVING THROUGH AREA THIS MORNING...THEN WEAK RIDGING THIS AFTERNOON INTO TONIGHT...FOLLOWED BY ANOTHER TROUGH APPROACHING LATE TONIGHT. AT 500 MB...NORTHERN LAKES SHORTWAVE TROUGH RETREATING EAST THIS MORNING...WEAK SHORTWAVE RIDGING IN ITS WAKE TODAY...ANOTHER WEAKER TROUGH REACHING NORTHERN LAKES REGION LATE TONIGHT. MODEL QPF FIELDS RATHER MEAGER THROUGH TONIGHT. RUC/GFS/WRFXX SHOW VERY LIGHT PRECIPITATION TODAY MAINLY THIS MORNING...THEN DRY TONIGHT...WHEREAS NAM/NGM DRY THROUGH TONIGHT. RESIDUAL VERY MODEST LOW TO MID LEVEL OMEGA LIFT DEPARTING EARLY THIS MORNING...SLIGHT AGAIN LATE TONIGHT...WHILE QVECTOR CONVERGENCE SLIGHT AT BEST TODAY AND SLIGHT TO MODEST TONIGHT. LOW LEVEL CONVERGENCE WEAK INTO THIS MORNING...SLIGHT AGAIN LATE TONIGHT MAINLY NORTH. 280K ISENTROPIC ASCENT WEAK AT BEST LATE TONIGHT...AS CONDENSATION PRESSURE DEFICITS DO DIP TO 20 TO 30 MB IN THE SAGINAW VALLEY PROXIMITY. RELATIVE HUMIDITY PRETTY LIMITED FOR MEASURABLE SNOW AS WELL. 850 TO 500 MB MOISTURE VERY MEAGER THROUGH TONIGHT...AND LOWER MOISTURE MODESTLY GOOD TODAY BEFORE TRENDING DRIER TONIGHT. WILL FOLLOW IDEA OF PREVIOUS FORECAST...WITH NO PRECIPITATION MENTION STRONGER THAN FLURRIES THROUGH TONIGHT...AND THAT MENTION PRIMARILY NORTH WHERE LOW LEVEL MOISTURE WILL BE AIDED BY LAKE MICHIGAN TRAJECTORIES. GOING A FEW DEGREES WARMER TODAY THAN YESTERDAY...AS 850 MB TEMPERATURES SLOWLY MODERATE. && .LONG TERM...WEDNESDAY THROUGH MONDAY...ISSUED 430 AM EST TUE DURING THE LONG TERM FORECAST...THE STRONG RIDGE THAT HAS BEEN IN PLACE OVER THE GULF OF ALASKA WILL START TO FLATTEN...CAUSING THE NORTHERN STREAM FLOW TO BECOME SLIGHTLY MORE ZONAL THROUGH FRIDAY. BY THIS WEEKEND THE FLOW BUCKLES AGAIN AS A CLOSED UPPER LOW SETS UP OFF THE PACIFIC NORTHWEST COAST...ALLOWING A RIDGE TO BUILD OVER THE WESTERN CONUS WITH A TROUGH SETTING UP OVER THE NORTHEASTERN STATES. TEMPERATURES WILL MODERATE THROUGH THURSDAY...THEN RETURN TO BELOW NORMAL BEHIND A COLD FRONT THAT WILL MOVE ACROSS THE CENTRAL GREAT LAKES ON SATURDAY. THE NEXT WAVE TO IMPACT THE REGION WILL MOVE ACROSS THE NORTHERN GREAT LAKES ON THURSDAY. THE ASSOCIATED SURFACE LOW IS EXPECTED TO TRACK ACROSS LAKE SUPERIOR TO SOUTHERN QUEBEC. THE 00Z/21 GFS IS AN OUTLIER SHOWING THIS LOW TRACKING ACROSS NORTHERN LOWER MICHIGAN AND BRINGING UP TO AN INCH OF SNOW TO THE NORTHERN HALF OF THE CWA. PREFER THE SOLUTION OFFERED UP BY THE MAJORITY OF OTHER MODELS SHOWING A MORE NORTHERN TRACK. A BROAD UPPER LEVEL TROUGH WILL BE SETTING UP OVER MOST OF THE NORTHERN CONUS AT THIS TIME...MAKING IT HARD FOR THIS LOW TO TRACK SOUTHEAST TOWARDS NEW YORK STATE. WILL CONTINUE WITH LOW CHANCE OF SNOW SHOWERS FOR THURSDAY IN THE NORTH WITH A PERIOD OF WEAK LIFT AS THE COLD FRONT SLIDES SOUTH. AM NOT ANY ACCUMULATION AT THIS TIME. SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL HELP TEMPERATURES WARM TO NEAR TO JUST ABOVE NORMAL FOR WEDNESDAY AND THURSDAY. EXACTLY HOW WARM WE GET ON THURSDAY WILL DEPEND ON FRONTAL TIMING BUT WOULD EXPECT THE SOUTHEASTERN CWA TO SEE TEMPS CLIMBING TO JUST ABOVE 40 AHEAD OF THE FRONT. WILL LEAN TOWARDS THE ECMWF FOR THE REMAINDER OF THE FORECAST AS THE GFS NEVER SEEMS TO GET BACK ON TRACK AFTER THE THURSDAY SYSTEM. THE ECMWF IS STILL ABOUT 12 HOURS BEHIND THE GFS FOR THE FRONTAL PASSAGE ON SATURDAY WITH THE REST OF THE MODELS SOMEWHERE IN BETWEEN. HAVE REMOVED PRECIP FOR FRIDAY WITH HIGH PRESSURE EXPECTED OVER THE CENTRAL GREAT LAKES. GOOD ISENTROPIC LIFT MOVES OVER THE AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF THE LOW BRINGING OUR BEST CHANCE FOR SNOW THIS WEEK. GOOD UPPER LEVEL DIVERGENCE WILL ALSO BE OVER THE AREA AND EXPECT TO SEE SOME LIGHT ACCUMULATIONS BY MIDDAY ON SATURDAY. A BLAST OF COLD AIR FILTERS IN OVER THE REGION THIS WEEKEND WITH 850MB TEMPS DROPPING TO -18 TO -20C. TEMPERATURES WILL BE BELOW NORMAL THROUGH THE BEGINNING OF NEXT WEEK WITH HIGHS IN THE LOW TO MID 20S FOR SUNDAY AND MONDAY. SNOW SHOWERS ARE POSSIBLE THROUGH SUNDAY NIGHT WITH COLD CYCLONIC FLOW OVER THE AREA AND THE POTENTIAL FOR SOME LAKE EFFECT SNOW SHOWERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BRAVENDER UPDATE.......BRAVENDER SHORT TERM...DWD LONG TERM....KAHL 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 JACKSON MS 316 PM CST TUE FEB 21 2006 .DISCUSSION...SHORT TERM(TONIGHT THROUGH WEDNESDAY NIGHT) SHALLOW ARCTIC AIR CONTINUES TO SLOWLY ERODE MAINLY FROM THE TOP DOWN WITH THICK(3K FT)TEMP INVERSION HUGGING THE SURFACE. WIDESPREAD CLOUD COVER WILL CONTINUE THROUGH THE SHORT TERM AS QSTNRY COASTAL FRONT EDGES SLOWLY NWD TONIGHT WITH LOW LEVEL WARM ADVECTION PATTERN SETTING UP. PATCHY LIGHT RAIN ALREADY DEVELOPING OVER MUCH OF AR AND THIS AREA SHOULD EXPAND THROUGH THE EVENING HOURS. 18Z RUC INDICATES THAT THE INVERSION WILL WEAKEN TO ABOUT 1.5K FEET TONIGHT AND IF ANY CLEAR "HOLES" DEVELOP IN THE LAYER...THEY WILL PROBABLY FILL BACK IN WITH FOG RATHER QUICKLY. HAVE OPTED NOT TO MENTION FOG FOR THIS FORECAST HOWEVER THE SRN PTNS OF THE CWFA COULD SEE SOME AND MIGHT HAVE TO BE ADDED IF RAIN SLOWER TO DEVELOP THAN WE THINK. MODELS BRING NEXT SHORTWAVE INTO OUR REGION LATE TONIGHT WITH RAIN BREAKING OUT FIRST FOR LOCATIONS N OF I-20 AND THEN SPREADING SWD ACROSS MOST OF FA BY MORNING. LOOK FOR WEAK BOUNDARY(INVERTED TROF) TO EMERGE ACROSS CENTRAL ZONES AS MID LEVEL GULF INFLOW IMPROVES TO HELP IN THE ISENTROPIC LIFT PROCESSES FROM 295-310K LEVELS. WILL KEEP HIGHEST POPS NRN AREAS FOR TONIGHT AND PRECIP AS LIGHT FOR NOW UNDER THE EVER-PRESENT SRN BRANCH OF THE UPPER JET LIVING OVER THE GULF STATES. MEANWHILE...A SURFACE-BASED BOUNDARY STALLED BETWEEN THE HIGHWAY 84 TO I-10 CORRIDORS WEDNESDAY WILL ATTEMPT TO EDGE NWD. LOW LEVEL WARM AIR ADVECTION INCREASES WITH BETTER MOISTURE(PWATS RISE TO NEAR 1.5" BY WEDNESDAY EVENING). SOME LIMITED MOSTLY-ELEVATED INSTABILITY RETURNS WITH PROGGED MLCAPES ACROSS SRN ZONES OF 100J/KG(GFS)/ 700J/KG(NAM)... K INDEXES 30-34...AND 7-500MB LAPSE RATES 6.25C. LOOK FOR SCATTERED THUNDERSTORMS BY WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING MOVING QUICKLY ENEWD THROUGH 325-328K 850MB THETA E AXIS. EXPECT LOCAL QPF TO REACH ONE HALF TO ONE INCH WHILE MOST LOCATIONS STAY IN THE ONE QUARTER TO ONE HALF INCH RANGE 18Z WED TO 12Z THURSDAY./40/ LONGER TERM (THURSDAY NEXT TUESDAY)... NOT MANY CHANGES MADE TO THE EXTENDED FORECAST. PATTERN SHIFT ON THE FAR HORIZON LOOKS TO BRING US AT LEAST A TEMPORARY BREAK FROM THE CLOUDS/WET BY SUNDAY. BUT...UNTIL THEN...EXPECT MORE "BLAH". AT LEAST IT WILL PROBABLY A LITTLE WARMER VARIETY OF YUCKY-NESS AS THE STAGNANT AND SHALLOW ARCTIC AIRMASS ONCE OVER THE REGION MODIFIES BY FRIDAY. IF ONLY THE SUN WOULD SHINE...SURFACE TEMPERATURES WOULD PROBABLY NOT HAVE TOO HARD A TIME GETTING UP INTO THE 60S. BUT...ALAS...THE SUN WILL BE HARD TO FIND THROUGH THE END OF THE WEEK AS THE DISTURBED SOUTHERLY STREAM REMAINS OVERHEAD AND THE NOW-RELENTING INVERSION BELOW 500 MB GETS RE-INVIGORATED BY ANOTHER COOL PUSH THURSDAY. THE BEST CHANCES FOR RAIN AFTER TOMORROW WILL COME FRIDAY INTO EARLY SATURDAY...BUT PATCHES OF DRIZZLE/SPRINKLES CANNOT BE RULED AT ANY POINT ACROSS THE CWA FROM THURSDAY THROUGH EARLY SATURDAY. FORTUNATELY...NO HEAVY RAINFALL IS ANTICIPATED AND HAZARDOUS WEATHER DOES NOT LOOK TO BE ON TAP THROUGH THE EXTENDED. POP NUMBERS WERE KEPT NEAR LATEST 00Z MEX GUIDANCE...BUT I DID BUMP UP THOSE NUMBERS SOME 10 TO 15 POINTS FOR THURSDAY NIGHT AS VARIOUS ENSEMBLE MEMBERS ARGUE THAT MOIST RETURN FLOW COULD PRECEDE THE NEXT MID LEVEL WAVE IN OUR AREA BY THAT TIME. TEMPERATURES ARE MORE TRICKY...ALTHOUGH I STILL DID NOT STRAY FAR FROM 00Z MEX (AND THUS THE PREVIOUS FORECAST). HIGHS WILL MAINLY BE IN THE 50S THROUGH THE EXTENDED WITH 60S POSSIBLE BY EARLY NEXT WORK WEEK. LOWS WILL GENERALLY RANGE FROM THE MID 30S TO MID 40S ALTHOUGH LIKELY CHILLING DOWN BELOW FREEZING FOR A NIGHT OR TWO BEHIND THE COLD FRONT THAT CLEARS US OUT FINALLY THIS WEEKEND. FINALLY...NO WINTRY WEATHER (IN TERMS OF PRECIP) IS EXPECTED IN THE FORECAST AREA DURING THE EXTENDED PERIOD OF THIS FORECAST PACKAGE./BB/ && .AVIATION... MOST LOCATIONS MANAGED TO BREAK THROUGH TO MVFR CEILINGS BY MID AFTERNOON AND THESE SHOULD CONTINUE FOR A FEW HOURS BEFORE IFR CONDITIONS RETURN 04-08Z TONIGHT THROUGH 16Z WEDNESDAY. ANY SPOTS THAT COULD POSSIBLY SEE CLOUDS BREAK OUT THIS EVENING WILL BE VULNERABLE TO QUICK FOG FORMATION AND LIFR CONDITIONS OVERNIGHT. HOWEVER EXPECT MOST VISIBILITIES IN DEVELOPING RAIN SETUP TO STAY 2-4SM THROUGH THURSDAY MORNING./40/ .PRELIMINARY POINT TEMPS/POPS... JACKSON 49 59 48 59 / 71 91 79 21 MERIDIAN 51 62 47 59 / 60 82 87 21 VICKSBURG 49 56 47 60 / 70 94 76 20 HATTIESBURG 53 69 53 64 / 37 57 82 33 NATCHEZ 52 61 48 63 / 51 85 81 27 GREENVILLE 44 49 43 57 / 84 97 48 13 GREENWOOD 43 50 43 55 / 90 97 50 12 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 40/50 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 327 PM CST TUE FEB 21 2006 .UPDATED SHORT TERM DISCUSSION... CLOUD COVER CONTINUES TO INCREASE THIS AFTERNOON AHEAD OF AN APPROACHING UPPER LEVEL DISTURBANCE OVER NORTH TEXAS. AREA RADARS SHOW INCREASING COVERAGE OF LIGHT ECHOES OVER SOUTHWEST MO/NORTHERN ARKANSAS SPREADING TO THE NORTHEAST. AREA SURFACE OBSERVATIONS SHOW LIGHT RAIN AND DRIZZLE ALREADY OCCURRING ALONG A LINE FROM HARRISON TO SALLISAW (E OK). MAIN CONCERN IN THE SHORT TERM WILL BE PRECIPITATION CHANCES TONIGHT. BASED ON CURRENT RADAR/SATELLITE INFO AND MODEL TRENDS WITH RESPECT TO LAYER RH PROGS...WILL GO AHEAD AND ADD LOW CHANCES FOR LIGHT RAIN THROUGH THE EVENING AND WILL DROP MENTION OF LIGHT RAIN/FLURRIES OVER CENTRAL MO AFTER MIDNIGHT. ONLY COMPLICATING FACTOR IN THE FORECAST THROUGH THE REST OF THE SHORT TERM WILL BE ANOTHER SHORTWAVE OVER THE SOUTHERN CALIFORNIA COAST TODAY GENERATING SOME LIGHT PRECIP IF ADEQUATE MOISTURE IS AVAILABLE AROUND THURSDAY NIGHT. AT THIS TIME IT APPEARS THE SHORTWAVE WILL SHEAR OUT IN WESTERLY FLOW BEFORE REACHING THE CENTRAL U.S.. SO WILL CONTINUE WITH DRY FORECAST AND NEAR NORMAL TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY...AS DRY PACIFIC HIGH BUILDS INTO THE REGION...AND SURFACE FRONT ALONG NORTHERN GULF COAST BLOCKS LOW LEVEL MOISTURE TRANSPORT. TERRY && .LONG TERM DISCUSSION MEDIUM RANGE MODELS HAVE BEEN MORE CONSISTENT LATELY WITH CONTINUING THE MAIN TROUGH ACROSS THE NORTHEAST...WITH A LARGE RIDGE ACROSS THE ROCKIES BY THIS WEEKEND. THE AMOUNT OF COLD AIR AND WHERE THE UPPER LEVEL JET STREAM WILL BE LOCATED IN THE CENTRAL U.S. ARE THE MAIN FORECAST CONCERNS IN THE EXTENDED PERIOD. HAVE CONTINUED WITH HPC SCENARIO WITH THE NEXT COLD FRONT MOVING ACROSS THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY REGION SATURDAY MORNING. THE COOLEST AIR SHOULD REMAIN ACROSS THE LAKE OF THE OZARKS WITH NEAR NORMAL ACROSS SOUTHWEST FORECAST AREA NEXT WEEKEND. THE DEPTH OF MOISTURE FOR THE FRONTAL BOUNDARY PASSAGE ON SATURDAY ALSO REMAINS IN QUESTION. AT THIS TIME...HAVE CONTINUED WITH A DRY FORECAST EXCEPT OVER THE FAR SOUTHERN FORECAST AREA. LATER SHIFTS WILL NEED TO RE-EVALUATE MOISTURE DEPTH AND THE STRENGTH OF THE ISENTROPIC LIFT DURING THIS TIME PERIOD. DUE TO THE STRONG RIDGE EXPECTED OVER THE WEEKEND...CONTINUED THE DRY FORECAST. HOWEVER...AS THE THERMAL GRADIENT BECOMES A QUESTION MARK BY MONDAY/TUESDAY. THIS MAY LEAD TO AN INCREASING THREAT OF RAIN/SNOW. TIME WILL TELL! JLT && .AVIATION... FOR 18Z TAFS...AREA OF STRATUS EXTENDS ALONG AND SOUTHWEST OF A LINE FROM SOUTHEAST KANSAS INTO NORTHEAST OKLAHOMA EARLY THIS AFTERNOON. RUC/NAM 925 MB RH FORECASTS SHOW HUMIDITIES ABOVE 80 PERCENT CLIPPING SOUTHWEST MO THROUGH EARLY EVENING...SO WILL CARRY SOME TEMPO MVFR CEILINGS THROUGH LATE AFTERNOON AT KJLN AND FROM LATE AFTERNOON INTO EARLY EVENING AT KSGF. OTHERWISE WILL CARRY MID LEVEL CLOUDS AHEAD OF APPROACHING UPPER DISTURBANCE THIS EVENING...AND CONTINUE TO DROP WINDS TO LIGHT AND VARIABLE FROM MID EVENING THROUGH THE NIGHT AS PRESSURE GRADIENT REMAINS WEAK OVER THE AREA. TERRY && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 259 PM CST TUE FEB 21 2006 .SHORT TERM DISCUSSION... CLOUD COVER CONTINUES TO INCREASE THIS AFTERNOON AHEAD OF AN APPROACHING UPPER LEVEL DISTURBANCE OVER NORTH TEXAS. AREA RADARS SHOW INCREASING COVERAGE OF LIGHT ECHOES OVER SOUTHWEST MO/NORTHERN ARKANSAS SPREADING TO THE NORTHEAST. AREA SURFACE OBSERVATIONS SHOW LIGHT RAIN AND DRIZZLE ALREADY OCCURRING ALONG A LINE FROM HARRISON TO SALLISAW (E OK). MAIN CONCERN IN THE SHORT TERM WILL BE PRECIPITATION CHANCES TONIGHT. BASED ON CURRENT RADAR/SATELLITE INFO AND MODEL TRENDS WITH RESPECT TO LAYER RH PROGS...WILL GO AHEAD AND ADD LOW CHANCES FOR LIGHT RAIN THROUGH MIDNIGHT OVER OUR SOUTHERN AND EASTERN ZONES...WITH LIGHT RAIN/FLURRIES OVER CENTRAL MO AFTER MIDNIGHT WHEN TEMPS FALL BELOW FREEZING. ONLY COMPLICATING FACTOR IN THE FORECAST THROUGH THE REST OF THE SHORT TERM WILL BE ANOTHER SHORTWAVE OVER THE SOUTHERN CALIFORNIA COAST TODAY GENERATING SOME LIGHT PRECIP IF ADEQUATE MOISTURE IS AVAILABLE AROUND THURSDAY NIGHT. AT THIS TIME IT APPEARS THE SHORTWAVE WILL SHEAR OUT IN WESTERLY FLOW BEFORE REACHING THE CENTRAL U.S.. SO WILL CONTINUE WITH DRY FORECAST AND NEAR NORMAL TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY...AS DRY PACIFIC HIGH BUILDS INTO THE REGION...AND SURFACE FRONT ALONG NORTHERN GULF COAST BLOCKS LOW LEVEL MOISTURE TRANSPORT. TERRY && .LONG TERM DISCUSSION MEDIUM RANGE MODELS HAVE BEEN MORE CONSISTENT LATELY WITH CONTINUING THE MAIN TROUGH ACROSS THE NORTHEAST...WITH A LARGE RIDGE ACROSS THE ROCKIES BY THIS WEEKEND. THE AMOUNT OF COLD AIR AND WHERE THE UPPER LEVEL JET STREAM WILL BE LOCATED IN THE CENTRAL U.S. ARE THE MAIN FORECAST CONCERNS IN THE EXTENDED PERIOD. HAVE CONTINUED WITH HPC SCENARIO WITH THE NEXT COLD FRONT MOVING ACROSS THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY REGION SATURDAY MORNING. THE COOLEST AIR SHOULD REMAIN ACROSS THE LAKE OF THE OZARKS WITH NEAR NORMAL ACROSS SOUTHWEST FORECAST AREA NEXT WEEKEND. THE DEPTH OF MOISTURE FOR THE FRONTAL BOUNDARY PASSAGE ON SATURDAY ALSO REMAINS IN QUESTION. AT THIS TIME...HAVE CONTINUED WITH A DRY FORECAST EXCEPT OVER THE FAR SOUTHERN FORECAST AREA. LATER SHIFTS WILL NEED TO RE-EVALUATE MOISTURE DEPTH AND THE STRENGTH OF THE ISENTROPIC LIFT DURING THIS TIME PERIOD. DUE TO THE STRONG RIDGE EXPECTED OVER THE WEEKEND...CONTINUED THE DRY FORECAST. HOWEVER...AS THE THERMAL GRADIENT BECOMES A QUESTION MARK BY MONDAY/TUESDAY. THIS MAY LEAD TO AN INCREASING THREAT OF RAIN/SNOW. TIME WILL TELL! JLT && .AVIATION... FOR 18Z TAFS...AREA OF STRATUS EXTENDS ALONG AND SOUTHWEST OF A LINE FROM SOUTHEAST KANSAS INTO NORTHEAST OKLAHOMA EARLY THIS AFTERNOON. RUC/NAM 925 MB RH FORECASTS SHOW HUMIDITIES ABOVE 80 PERCENT CLIPPING SOUTHWEST MO THROUGH EARLY EVENING...SO WILL CARRY SOME TEMPO MVFR CEILINGS THROUGH LATE AFTERNOON AT KJLN AND FROM LATE AFTERNOON INTO EARLY EVENING AT KSGF. OTHERWISE WILL CARRY MID LEVEL CLOUDS AHEAD OF APPROACHING UPPER DISTURBANCE THIS EVENING...AND CONTINUE TO DROP WINDS TO LIGHT AND VARIABLE FROM MID EVENING THROUGH THE NIGHT AS PRESSURE GRADIENT REMAINS WEAK OVER THE AREA. TERRY && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION...UPDATED AVIATION DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1155 AM CST TUE FEB 21 2006 .DISCUSSION (135 AM)... FAST QUASI-ZONAL FLOW REMAINS IN PLACE ACROSS THE LOWER 48 EARLY TUESDAY WITH THE CONFLUENCE OF THE NORTHERN AND SOUTHERN STREAMS FROM THE MIDWEST AND ACROSS THE OHIO VALLEY. RATHER BENIGN SURFACE PATTERN IN PLACE WITH SURFACE HIGH PRESSURE CENTERED OVER EASTERN ARKANSAS. STRATUS THAT LINGERED INTO THE EVENING ACROSS THE OZARKS HAD FINALLY DISSIPATED EARLY TUESDAY. HOWEVER LIGHT FOG HAD BEGUN TO FORM IN RESPONSE TO THE CLEARING SKIES AND MOIST BOUNDARY LAYER IN AREAS THAT RECEIVED SNOW OVER THE WEEKEND. NEAR SEASONABLE TEMPERATURES AND RATHER TRANQUIL WEATHER CONDITIONS WILL PREVAIL THE NEXT FEW DAYS WITH NO MAJOR SYSTEMS PROGGED TO IMPACT THE REGION. FOG POTENTIAL WILL BE MONITORED THIS MORNING AND WILL LIKELY INCLUDE AT LEAST PATCHY FOG IN THE GRIDS. TEMPERATURES WILL WARM TO NEAR NORMAL ACROSS MUCH OF THE FORECAST AREA TODAY WITH THE HELP OF MORE SUNSHINE. HOWEVER EXITING SNOW COVER ACROSS FAR SOUTHERN MISSOURI WILL HOLD TEMPERATURES DOWN IN THAT AREA. A SUBTLE AND INCREASINGLY SHEARED SHORTWAVE WILL TRACK ACROSS THE REGION TONIGHT. WEAK ISENTROPIC LIFT WILL BRING CLOUDS BACK INTO THE AREA THIS EVENING. THE POTENTIAL FOR ANY PRECIPITATION LOOKS SLIM AT BEST AS DEEPER MOISTURE AND BEST...ALBEIT WEAK SYNOPTIC SCALE LIFT REMAINS TO OUR SOUTH. HAVE TRIMMED PRECIPITATION CHANCES TO FAR SOUTH CENTRAL MISSOURI WHERE THERE MAY BE SOME SPRINKLES TONIGHT. ANOTHER WEAK SHORTWAVE WILL TRACK INTO THE LOWER MISSISSIPPI RIVER VALLEY WEDNESDAY. AGAIN THE ASSOCIATED LIFT AND DEEP MOISTURE IS PROGGED TO REMAIN TO THE SOUTH. THE SHORTWAVE NOW OFF OF THE CALIFORNIA COAST WILL EVENTUALLY EJECT EASTWARD BY LATE WEEK. MODELS DIFFER ON THE TRACK AND EVOLUTION OF THIS SYSTEM. THE NAM IS THE STRONGER AND FARTHEST NORTH WITH DEEPER MOISTURE AND PRECIPITATION SPREADING ACROSS THE SOUTHERN PLAINS. NO CHANGES TO THE FORECAST PLANNED AT THIS TIME BUT THIS SYSTEM WILL HAVE TO BE MONITORED. A COLD FRONT WILL MOVE THROUGH THE REGION LATE FRIDAY PROVIDING SEASONABLY COLD TEMPERATURES THIS WEEKEND. FOSTER && .AVIATION... FOR 18Z TAFS...AREA OF STRATUS EXTENDS ALONG AND SOUTHWEST OF A LINE FROM SOUTHEAST KANSAS INTO NORTHEAST OKLAHOMA EARLY THIS AFTERNOON. RUC/NAM 925 MB RH FORECASTS SHOW HUMIDITIES ABOVE 80 PERCENT CLIPPING SOUTHWEST MO THROUGH EARLY EVENING...SO WILL CARRY SOME TEMPO MVFR CEILINGS THROUGH LATE AFTERNOON AT KJLN AND FROM LATE AFTERNOON INTO EARLY EVENING AT KSGF. OTHERWISE WILL CARRY MID LEVEL CLOUDS AHEAD OF APPROACHING UPPER DISTURBANCE THIS EVENING...AND CONTINUE TO DROP WINDS TO LIGHT AND VARIABLE FROM MID EVENING THROUGH THE NIGHT AS PRESSURE GRADIENT REMAINS WEAK OVER THE AREA. TERRY && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1028 AM CST TUE FEB 21 2006 .UPDATE...MINOR MODIFICATIONS MADE TO THE FORECAST THIS MORNING. FRESHENED UP GRIDS FOR LATEST CONDITIONS...INCLUDING BUMPING UP POPS IN THE NW AS SNOW CONTINUES TO ENCROACH FROM THE NW. MODELS KEEP MOST OF THE PRECIP TO THE NORTH TODAY...AND KEPT WITH THAT GENERALLY THINKING. TEMPS HAVE RISEN INTO THE LOWER 30S IN MBG AS WINDS WENT WEST. BELIEVE THIS WILL BE THE CASE FOR MUCH OF THE AREA. ONLY NEEDED TO NUDGE HIGHS UP SLIGHTLY. KNUTSVIG .PREVIOUS FORECAST... .SHORT TERM...TODAY THROUGH THURSDAY NIGHT UPPER WAVE AND ASSOCIATED SFC LOW STILL ON TRACK TO SLIDE SE OUT OF CANADA THIS MORNING...MOVE ACROSS THE DAKOTAS AND MAKE ITS WAY INTO MN BY EARLY THIS EVENING. BEST LIFT NOTED BY GFS/NAM/RUC ACROSS NE CWA AND POPS WERE LEFT HIGHEST IN THIS LOCATION. SFC OBS UPSTREAM IN WESTERN ND/SOUTHERN CANADA HAVE SHOWN LIGHT SNOW MOST OF THE NIGHT AND EXPECT SOME OF THIS ACTIVITY TO MAKE IT INTO THE NE CWA BY LATE MORNING AND EARLY AFTERNOON. AS SFC TROUGH SLIDES ACROSS AREA...LIGHT SOUTH WINDS IN THE MORNING WILL GRADUALLY TURN TO THE SW THEN W THROUGHOUT THE DAY. EXPECT BREEZY CONDITIONS TO DEVELOP ACROSS MISSOURI RIVER VALLEY. NEXT WAVE IN PROGRESSIVE PATTERN SLIDES SE ON WED NIGHT. RATHER UNIMPRESSIVE LOOKING SYSTEM AND CURRENT SLIGHT CHANCE POPS STILL SEEM APPROPRIATE. WEAK SFC HIGH AND MID LEVEL RIDGING THEN MOVES IN FOR THURS AND SHOULD BE A FAIRLY QUIET DAY. IT WILL BE COLDER AS A COLD FRONT WILL SLIP SOUTH ACROSS THE CWA BEHIND WED NIGHT SYSTEM. TEMPERATURES WERE CHANGED LITTLE AS QUICK MOVING WAVES WILL BRING SHORT PERIODS OF WAA AND CAA THROUGH THE AREA DURING THE PERIOD. DID NOT WANT TO STRAY TOO FAR FROM INHERITED FORECAST UNTIL PERIODS GET CLOSER AND INFLUENCE OF WAA/CAA CAN BE BETTER DEFINED. .LONG TERM...FRIDAY THROUGH MONDAY MODELS AGREE BETTER NOW ON THE TRACK OF THE SURFACE LOW PRESSURE AREA AFFECTING THE REGION IN THE FRIDAY/FRIDAY NIGHT TIME PERIOD. WITH DIFFERENCES IN THE SPEED AND STRENGTH OF THE SURFACE LOW PRESSURE AREA...THE MODELS AGREE MORE THAT THE LOW TRACK WILL BE TO THE NORTH OF OUR CWA. THE ECMWF TRACK WAS FURTHER SOUTH ALONG THE ND/SD BORDER WHILE THE NAM AT 84 HOURS HAD THE SURFACE LOW FURTHER NORTH INTO SOUTHERN CANADA. THUS...KEPT A 20 POP FOR SNOW ACROSS THE NORTHERN PART OF THE CWA AND THAT MAY BE A STRETCH IF THE LOW TRACK IS WELL TO THE NORTH. ALSO...FRIDAY'S TEMPERATURES WILL BE INTERESTING IN THE WARM SECTOR IF THE SFC LOW IS WELL TO THE NORTH. TEMPERATURES MAY BE EVEN WARMER THAN THE CURRENT FORECAST. OTHERWISE...IT LOOKS LIKE STRONG CAA WILL OCCUR IN BEHIND THE LOW WITH POSSIBLY A PERIOD OF WINDY CONDITIONS FRIDAY AFTERNOON AND NIGHT. THE REST OF THE EXTENDED LOOKS DRY WITH BELOW NORMAL TEMPERATURES AS LARGE SURFACE HIGH PRESSURE DOMINATES THE WEATHER. THE DEVELOPMENT OF THE UPPER LOW OVER THE EASTERN UNITED STATES WILL AFFECT THE MOVEMENT OF THE FRONTAL BOUNDARY ACROSS OUR REGION. IT LOOKS AS IF SUNDAY AND MONDAY WILL BE COOLER THAN PREVIOUS FORECAST AS COLDER AIR HOLDS IN...ESPECIALLY ACROSS THE EAST. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ TT/DM sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 403 PM CST TUE FEB 21 2006 .SHORT TERM....SHORT-TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...THE WARM FRONT HAS PENETRATED PORTIONS OF THE COASTAL COUNTIES LATE THIS AFTERNOON AND WILL SLOWLY ADVANCE ACROSS THE REMAINDER OF THE CWA TONIGHT/WEDNESDAY MORNING. THIS FRONT WILL THEN ENCROACH UPON THE NORTHERN CWA AS A COLD FRONT LATE WEDNESDAY NIGHT. THE CHIEF CONCERN WILL BE NIGHTTIME/MORNING ADVECTION FOG AS A SIGNIFICANT SST/DEWPOINT DIFFERENTIAL WILL EXIST. HAVE ISSUED A DENSE FOG ADVISORY FOR ALL BUT THE WESTERN RIO GRANDE PLAINS THROUGH LATE WEDNESDAY MORNING AS CONDITIONS LOOK RIPE. SHOULD BE NEARLY A REPEAT PERFORMANCE WEDNESDAY NIGHT BUT SOME SYNOPTIC-SCALE VERTICAL MOTIONS MAY IMPEDE WIDESPREAD AREAL COVERAGE. BOUNDARY LAYER FORCING AND MACROSCALE FORCING FROM WEAK MID-LEVEL DISTURBANCES SUPPORTS SLIGHT CHANCE/MARGINAL LOW-END CHANCE POPS WEDNESDAY AFTERNOON/WEDNESDAY NIGHT. FOLLOWED THE RUC TEMPERATURES TONIGHT WITH NO SIGNIFICANT DEPARTURES THEREAFTER. && .MARINE...SIGNIFICANT SST/DEWPOINT DIFFERENTIAL WILL RESULT IN A SEA FOG EPISODE THROUGH WEDNESDAY NIGHT. HAVE ACCORDINGLY ISSUED A MARINE WEATHER STATEMENT. && .AVIATION...VFR/MVFR CIGS LATE THIS AFTERNOON WILL RAPIDLY DETERIORATE TO WIDESPREAD IFR/LIFR VSBYS/CIGS DUE TO ADVECTION FOG ALONG THE COAST EARLY THIS EVENING THEN SPREAD TO THE COASTAL PLAINS BY MID EVENING AND FINALLY TO THE WESTERN RIO GRANDE PLAINS AFTER MIDNIGHT. THIS FOG WILL PERSIST UNTIL LATE WEDNESDAY MORNING. CONDITIONS WILL IMPROVE TO VFR/MVFR CIGS WEDNESDAY AFTERNOON. && .LONG-TERM (THURSDAY THROUGH TUESDAY)...COOL HIGH PRESSURE WILL BUILD SE OUT OF THE ROCKIES INTO THE PLAINS THROUGH THURSDAY WITH THE HELP OF A PACIFIC RIDGE AND A WEAK BROAD TROUGH SHIFTING ACROSS THE NRN PLAINS INTO THE NERN US. UPPER LEVEL FLOW REMAINS WSW ACROSS THE SRN HALF OF THE COUNTRY BUT MODELS STILL INDICATE ENOUGH DENSITY TO SLOWLY PUSH A WEAK AND SHALLOW FRONT INTO THE COASTAL BEND ON THURSDAY. THE GFS AND NAM BOTH SHOW THE BOUNDARY STALLING NEAR THE COAST WITH A COASTAL TROUGH/FRONT DEVELOPING THROUGH FRI AS HIGH PRESSURE BUILDS ACROSS THE MS RIVER VALLEY. GFS AND NAM BOTH INDICATE LOTS OF MOISTURE POOLED ALONG AND BEHIND THE BOUNDARY WITH WEAK ISENTROPIC LIFT OVER THE SHALLOW COOL AIRMASS. A 150KT+ JET STREAK IS PROGGED TO REMAIN WELL TO THE NORTH AND APPEARS ANY UPR S/WVS IN THE WSW FLOW WILL REMAIN WEAK SO CURRENT INDICATIONS IS ANY RAINFALL WITH THIS SYSTEM WILL REMAIN LIGHT DESPITE HIGH MOISTURE VALUES. STILL...VERY HIGH MOISTURE VALUES (PWS NEAR 1.5 INCHES)... THE BOUNDARY NEARBY...AND ISENTROPIC LIFT WILL WARRANT SLT CHC/CHC POPS FOR LIGHT RAIN/SHOWERS THU THROUGH SAT WITH CLOUD COVER AND WEAK CAA HOLDING TEMPS DOWN SOME (ALTHOUGH NOTHING LIKE THIS PAST WEEKEND). GFS CONTINUES TO SHOW A STRONGER AND COLDER CANADIAN HIGH BUILDING SOUTH OVER THE WEEKEND...BUT THE 12Z RUN IS SHOWING THE HIGH CENTER PUSHING MORE SE ACROSS THE MID WEST AND INTO THE SERN US WHICH MAKES SINCE BASED ON THE UPR PATTERN AND AGREES MORE W/ THE 00Z ECMWF. STILL...THE HIGH IS PROGGED TO BUILD INTO THE REGION ENOUGH TO PROLONG THE COASTAL TROUGH AND ISENTROPIC UPGLIDE SITUATION THROUGH THE WEEKEND AS PWS REMAIN VERY HIGH. UPR JET STREAK WEAKENS BUT MAY SEE A BIT MORE FAVORABLE JET POSITION AND THEREFORE SLIGHTLY BETTER DYNAMIC LIFT SAT AND EARLY SUN BUT STILL NOT CONVINCED AND WILL KEEP POPS IN CHC/SCT CATEGORY SAT AND SUN (STILL REMAINING BELOW GUIDANCE). ALSO...GIVEN UNIMPRESSIVE UPR DYNAMICS...NOT BUYING TO MUCH INTO HIGHER QPF AMOUNTS PROGGED BY GFS LAST FEW RUNS (1/4 TO 3/4 INCH SAT-EARLY SUN). MOISTURE IS VERY IMPRESSIVE THOUGH GIVEN THE TIME OF YEAR AND ANY SMALL DISTURBANCE COULD ENHANCE PRECIP THIS PERIOD AND WILL HAVE TO WATCH CLOSELY. GIVEN A WEAKER FRONT HAVE RAISED TEMPS CLOSER TO 12Z MEX VALUES OVER THE WEEKEND. CONDITIONS SHOULD IMPROVE EARLY NEXT WEEK AS HIGH PRESSURE MOVES INTO THE SERN US AND SRLY FLOW RETURNS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 63 79 65 74 59 / 10 20 20 20 30 VICTORIA 60 75 62 67 55 / 10 20 30 30 40 LAREDO 58 83 65 73 57 / 10 20 20 20 30 ALICE 60 81 65 74 57 / 10 20 20 20 30 ROCKPORT 63 74 65 72 58 / 10 20 20 20 30 COTULLA 53 80 62 71 55 / 10 20 30 20 40 KINGSVILLE 62 80 65 76 60 / 10 20 20 20 30 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...DENSE FOG ADVISORY FROM 6 PM WEDNESDAY TO 10 AM THURSDAY FOR THE FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD... JIM WELLS...KLEBERG...LIVE OAK...MCMULLEN...NUECES... REFUGIO...SAN PATRICIO...AND VICTORIA. GM...NONE. && $$ BB/85...SHORT-TERM MG/88...LONG-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1050 AM CST TUE FEB 21 2006 .UPDATE...WARM FRONT STILL OFFSHORE AS EXITING WEAK MID-LEVEL SHORTWAVE OVER THE GLFMEX HAS IMPEDED IT/S PROGRESS. 12Z SOUNDING INDICATES THAT THE COLD DOME OF AIR IS VERY SHALLOW(~600FT DEEP) BUT UPSTREAM ISALLOBARIC PRESSURE FALLS THIS AFTERNOON WILL NOT BE HIGHLY CONDUCIVE TO YANK THE FRONT RAPIDLY NORTHWEST. THE RUC MODEL CONTINUES TO HANDLE THE SYNOPTIC SITUATION BEST AND WILL BE FOLLOWED CLOSELY. WILL CONFINE SKIES BECOMING PARTLY CLOUDY TO THE WESTERN RIO GRANDE PLAINS WHERE THE INVERSION WEAKENS SUFFICIENTLY. WILL RETAIN PATCHY FOG THROUGH THE AFTERNOON HOURS OVER THE EASTERN THIRD OF THE CWA AS ADVECTION FOG WILL BECOME MORE PROMINENT. CONFINED TEMPERATURES TO THE MID AND UPPER 60S OVER THE EAST AND LOWER TO MID 70S WEST. && .MARINE...SLOWED WESTWARD PROGRESS OF WARM FRONT AND LOWERED WIND SPEEDS THIS AFTERNOON. RETAINED PATCHY FOG THROUGH THE AFTERNOON HOURS OVER THE BAYS/NEARSHORE WATERS AS SEA FOG WILL BEGIN TO BECOME MORE PROMINENT. && .AVIATION...IFR VSBYS/CIGS DUE TO FOG WILL IMPROVE TO MVFR CONDITONS THIS AFTERNOON. VFR CONDITIONS WILL DEVELOP AFTER 20Z FROM LRD-COT. LOW CLOUDS/FOG EXPECTED TO DEVELOP AGAIN TONIGHT AND EXPECT IFR CONDS EAST OF HBV/COT LINE WITH MVFR CONDS IN LOW CLOUDS AT LRD. IN ADDITION...LIFR CONDS FOR VV001/1/4SM FG CAN BE EXPECTED OUT OVER PARTS OF THE BAYS AND NEARSHORE WATERS AS SEA FOG DEVELOPS OVERNIGHT AND PERSISTS INTO WEDNESDAY. && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ BB/85...UPDATE/MARINE/AVIATION tx