Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/04/12


AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
953 AM MST SUN DEC 2 2012 .UPDATE... ISSUED AT 952 AM MST SUN DEC 2 2012 BROAD BAROCLINIC LEAF CURRENTLY OVER THE NORTHERN ROCKIES IS BRINGING PLENTY OF PRECIPITATION TO THAT AREA WHILE WE REMAIN RELATIVELY CLOUD FREE. THIS WILL ALL CHANGE OVER THE NEXT FEW HOURS AS CLOUDS START TO THICKEN FROM THE NORTHWEST AND LOWER THROUGH THE DAY. NO HUGE CHANGES TO GOING FORECAST THOUGH NAM12 AND HRRR CROSS SECTIONS FROM VERNAL THROUGH CRAIG TO STEAMBOAT SPRINGS DO SHOW MINIMAL MOISTURE IN MID TO LOWER LEVELS INCLUDING THE DENDRITIC GROWTH REGION UNTIL 03Z. FOR THIS UPDATE THEN...BUMPED BACK ONSET OF PRECIP TO THIS EVENING WITH MOST PRECIP EXPECTED AFTER MIDNIGHT. $$ .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 408 AM MST SUN DEC 2 2012 WHILE THE CASCADES GET POUNDED WITH MOISTURE...THE ROCKIES GET JUST A SMALL DRINK. AT THIS POINT WE WILL HAPPILY TAKE ANYTHING. A VIGOROUS TROUGH WORKS INTO THE PACIFIC NORTHWEST THIS MORNING AND WILL SWEEP TO THE NORTH OF OUR FORECAST AREA TONIGHT INTO MONDAY. MODELS REMAIN IN GOOD AGREEMENT WITH TIMING AND IMPORTANT STORM DETAILS. 700MB FLOW BACKS FROM SW TO SSW TODAY AND STRENGTHENS TO 40/25KTS NORTH/SOUTH THIS AFTERNOON. THIS WARM ADVECTIVE PATTERN WILL BRING MID-HIGH CLOUDS AND AFTERNOON TEMPERATURES NEAR RECORD VALUES. IN SPITE OF THE WARMTH...DEEP VALLEY MIXING WILL BE LIMITED MAINLY TO THE NORTHERN VALLEYS. DEEPER MOISTURE (PRECIP WATER OF 0.6 INCHES) ARRIVES LATE THIS AFTERNOON AND EVENING AS THE RIGHT ENTRANCE QUADRANT OF THE UPRIGHT JET PRODUCES MID LEVEL Q CONVERGENCE OVER THE NORTHERN CWA. THE COOL FRONT WORKS THROUGH THE NORTHERN AND CENTRAL ZONES AFTER MIDNIGHT AND INTO MONDAY MORNING. FLOW VEERS TO WEST TONIGHT THEN WNW ON MONDAY WITH 700MB TEMPERATURES ONLY LOWERING TO -6/-1C NORTH/SOUTH. THESE RELATIVELY MILD MTN TOP TEMPERATURES LOWER SNOW LEVELS TO AROUND 6000FT NORTH...8500 FEET SOUTH. IT WILL ALSO PRODUCE A RELATIVELY WET MTN SNOW STARTING OUT AT 10:1 RATIO THIS EVENING AND INCREASING TO 14:1 TOWARDS MONDAY MORNING. MOISTURE QUICKLY DIMINISHES FROM NW TO SE ON MONDAY. WITH ONLY A -20C COLD CORE ACROSS THE NORTH...MONDAY INSTABILITY WILL BE VERY LIMITED. THEREFORE SUB ADVISORY SNOW AMOUNTS ARE EXPECTED EVEN FOR THE FAVORED NORTHERN MTNS. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 408 AM MST SUN DEC 2 2012 CLEARING AND COOLER CONDITIONS EXPECTED MONDAY NIGHT IN THE WAKE OF EXITING WAVE AS WEAK SHRTWV RIDGING BUILDS IN FROM THE WEST. PATTERN REMAINS PROGRESSIVE WITH MID AND HIGH LEVEL PACIFIC MOISTURE CONTINUING TO PUSH THROUGH THE REGION BRINGING PERIODS OF CLOUDS AND POSSIBLY A FEW SHOWERS ACROSS THE NORTHERN MOUNTAINS BY EARLY WEDNESDAY AS THE RIDGE BREAKS DOWN. ANOTHER STRONGER SYSTEM APPROACHES LATE WEDNESDAY NIGHT AND THURSDAY...PROMISING MORE HIGH ELEVATIONS SNOW AS THE WARM NATURE OF THIS SYSTEM KEEPS SNOW LEVELS AOA 8K. THIS SYSTEM EXITS THURSDAY AFTERNOON AND EVENING WITH ANOTHER BREAK FRIDAY AND SATURDAY AS HEIGHTS START TO CLIMB ALONG THE WEST COAST. PATTERN BECOMES MORE INTERESTING LATE SATURDAY AND SUNDAY...ESPECIALLY IN THE GFS WHICH ADVERTISES A FAIRLY NICE SURGE OF COLDER AIR AND MOISTURE AS WE CLOSE OUT THE WEEKEND. HOWEVER...TRAJECTORY OF THE SYSTEM COMING ACROSS CANADA AND THE NORTHERN ROCKIES SHOULD ELIMINATE MUCH OF THE OVERLY INFLATED QPF VALUES...BUT WITH A COLDER AIRMASS...COULD STILL SEE SIGNIFICANT PRECIPITATION. AS HAS BEEN THE CASE THIS SEASON...THE ECMWF NOT QUITE IN AGREEMENT AT THIS TIME...SO CONFIDENCE REMAINS LOW. TEMPERATURES WILL REMAIN AOA SEASONAL NORMS THROUGH THURSDAY...WITH SLIGHTLY COOLER WEATHER EXPECTED FRIDAY AND SATURDAY WITH MORE SIGNIFICANT COOL DOWN POSSIBLY ARRIVING FOR SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z NOON MONDAY) ISSUED AT 952 AM MST SUN DEC 2 2012 VFR IS EXPECTED THROUGH THIS EVENING THOUGH CLOUDS WILL INCREASE IN DEPTH AND COVERAGE AS THE DAY PROGRESSES. EXPECT BKN TO OVC SKIES TO BECOME PREDOMINANT AS THE DAY WEARS ON. BY 06Z TONIGHT...SOME MVFR POSSIBLE FOR KCAG...KHDN...KSBS...KRIL...KASE...AND KEGE AFTER 06Z AS CIGS/VIS DROP DUE TO RAIN SHOWERS AND SNOW. THESE CONDITIONS WILL PERSIST THROUGH 15Z OR SO. DURING THE DAY MONDAY...PRECIP WILL SHIFT SOUTHWARD BUT AS IT DOES IT WILL WEAKEN KEEPING CONDITIONS MOSTLY VFR. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...TGR SHORT TERM...JOE LONG TERM...JDC AVIATION...TGR
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1233 PM EST SUN DEC 2 2012 .SYNOPSIS... HIGH PRESSURE WILL PREVAIL EARLY THIS WEEK...WHILE A WEAK COASTAL TROUGH PERSISTS ALONG THE SOUTHEAST COAST. A COLD FRONT WILL THEN PASS THROUGH THE AREA WEDNESDAY NIGHT FOLLOWED BY COOLER HIGH PRESSURE FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NUDGED HIGH TEMPERATURES UP A DEG OR TWO FOR MOST LOCATIONS PER GOING TRENDS. OTHERWISE...THE FORECAST IS ON TRACK. CLOUDS OFF THE GEORGIA COAST POSE SOME CONCERN AS THEY COULD MAKE A RUN FOR THE COAST AND YIELD MOSTLY CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON. RAP 295K ISENTROPIC PROG SHOWED THE AREA OF CLOUDINESS RATHER WELL AND KEEPS THE BULK OF IT OFFSHORE. DID NOT MAKE ANY CHANGES TO THE SKY FORECAST IN AREA FOR THIS REASON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... TONIGHT...HIGH PRESSURE WILL SHIFT SOUTHWARD OFF THE CAROLINA COAST ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP...WHICH WILL HELP TO ADVECT GREATER LOW LEVEL MOISTURE INTO THE AREA. THIS MOISTURE COMBINED WITH DECOUPLED WINDS COULD POTENTIALLY LEAD TO AREAS OF FOG WHICH COULD BECOME LOCALLY DENSE AT TIMES. HOWEVER...THE BIG UNCERTAINTY IS THE EXTENT OF CLOUD COVER OVER THE AREA AS CONTINUED WEAK ISENTROPIC ASCENT COULD SUPPORT PARTLY TO MOSTLY CLOUDY SKIES THROUGH MUCH OF THE NIGHT. GIVEN THIS UNCERTAINTY...THE FORECAST WILL JUST INDICATE PATCHY FOG AT THIS TIME UNTIL SKY COVER TRENDS CAN BECOME BETTER ESTABLISHED. ISOLATED SHOWERS ARE POSSIBLE TONIGHT ONCE AGAIN JUST OFFSHORE...AND THE POTENTIAL IS THERE FOR SOME OF THEM TO SHIFT INLAND AND AFFECT COASTAL COUNTIES. TONIGHT WILL BE UNSEASONABLY WARM WITH THE DEVELOPING RETURN FLOW AND EXPECTED CLOUD COVER KEEPING LOWS IN THE LOWER 50S INLAND AND MID TO UPPER 50S NEAR THE IMMEDIATE COAST. DEEP HIGH PRESSURE OVER THE AREA MONDAY ALONG WITH A COASTAL TROUGH OF LOW PRESSURE OVER THE NEARBY ATLANTIC WILL SLOWLY BREAK DOWN THROUGH MID WEEK AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT LOOKS TO PUSH INTO THE AREA LATE IN THE DAY WEDNESDAY FROM THE NORTHWEST. OVERALL EXPECT LOW RAIN CHANCES THROUGH THE PERIOD. THERE WILL BE A RISK FOR FOG EACH MORNING DUE TO SUFFICIENT LOW-LEVEL MOISTURE AND LIGHT WINDS...ESPECIALLY MONDAY AND TUESDAY...AND IT COULD BECOME DENSE. TEMPERATURES WILL BE WELL ABOVE NORMAL THROUGH THE PERIOD...WITH LOWER TO MID 70S FOR HIGHS AND GENERALLY AROUND 50 FOR LOWS /COOLEST INLAND AND WARMEST ALONG THE COAST/. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... PRETTY GOOD MODEL AGREEMENT THROUGH THE END OF THE WEEK WITH MORE DISAGREEMENT LATE NEXT WEEKEND. A COLD FRONT WILL PASS SOUTHEAST THROUGH THE AREA WEDNESDAY NIGHT WITH A HIGH PRESSURE WEDGE SETTING UP THURSDAY INTO FRIDAY...WITH A COASTAL TROUGH OFFSHORE. ATLANTIC HIGH PRESSURE THEN LOOKS TO DOMINATE SATURDAY INTO SUNDAY WITH THE POSSIBILITY OF ANOTHER FRONT LATE IN THE WEEKEND. SMALL RAIN CHANCES WILL CONTINUE THURSDAY AND COULD LINGER NEAR THE COAST INTO FRIDAY DUE TO THE COASTAL TROUGH AND THEN COULD INCREASE FROM THE WEST AS EARLY AS LATE SATURDAY DEPENDING ON THE SPEED OF THE NEXT FRONT. HIGH TEMPERATURES WILL BE CLOSE TO NORMAL THURSDAY BEFORE MODERATING TOWARD THE END OF TH WEEK. LOWS SHOULD REMAIN ABOVE NORMAL. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE AFTERNOON WITH FORECAST CONFIDENCE WANING THEREAFTER. OVERNIGHT...FOG DEVELOPMENT WILL GREATLY DEPEND ON CLOUD COVERAGE. EXPECT SOME SCATTERED CLOUDS TO LINGER INTO AT LEAST THE FIRST PORTION OF THE NIGHT...BUT SOME MODELS SUGGEST DECENT CLEARING AFTER MIDNIGHT. IF CLEARING DEVELOPS...DECENT TO EXCELLENT RADIATIONAL COOLING CONDITIONS COULD RESULT IN SCATTERED TO DENSE FOG. AT THIS POINT...WILL MAINTAIN LOW-END MVFR VISIBILITIES AFTER 07Z AND WILL REEVALUATE FOG POTENTIAL AT LATER TAF ISSUANCES. EXTENDED AVIATION OUTLOOK...MVFR CEILINGS AND VISIBILITIES ARE EXPECTED DURING THE LATE NIGHT/EARLY MORNING HOURS THROUGH WEDNESDAY WITH IFR OR WORSE CONDITIONS LIKELY. LOW CIGS LOOK TO RETURN WEDNESDAY NIGHT INTO THURSDAY ALONG AND BEHIND A COLD FRONT. && .MARINE... THIS AFTERNOON...WW4 OUTPUT SHOWS SEAS AT 6 FT OVER THE EASTERN HALF OF THE GEORGIA OFFSHORE ZONE THIS MORNING. SEAS AT BOTH 41004 AND 41008 MATCH WW4 OUTPUT ALMOST EXACTLY...SO SEE NO REASON TO QUESTION ITS DEPICTION OF 6 FT SEAS. 6 FT SEAS WILL REMAIN OVER THE GEORGIA OFFSHORE LEG THROUGH LATE AFTERNOON AS THE SWELL TRAIN THAT WAS GENERATED BY LONG-FETCH EASTERLY FLOW OVER THE OPEN ATLANTIC CONTINUES TO IMPACT THE LOCAL MARINE AREA. HAVE ISSUED A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL LATE AFTERNOON TO ADDRESS THIS SITUATION. TONIGHT...HIGH PRESSURE WILL DROP SOUTHWARD OFF THE COAST OF THE CAROLINAS...ALLOWING A SOUTH OR SOUTHEAST FLOW TO DEVELOP OVER THE COASTAL WATERS WITH SPEEDS GENERALLY 10 KT OR LESS. SEAS WILL SUBSIDE BY ABOUT A FOOT OR SO THROUGH THE NIGHT. SUNDAY THROUGH FRIDAY...ATLANTIC HIGH PRESSURE WILL CONTINUE TO BE THE DOMINANT WEATHER FEATURE ACROSS THE SC/GA COASTAL WATERS THROUGH TUESDAY WITH A TROUGH OF LOW PRESSURE LINGERING NEARBY. A COLD FRONT WILL THEN PUSH THROUGH WEDNESDAY NIGHT FOLLOWED BY HIGH PRESSURE WEDGING DOWN THE COAST FROM THE NORTH THURSDAY INTO FRIDAY. SEAS COULD REACH 6 FT ACROSS THE EASTERN PORTIONS OF THE OUTER GA WATERS SUNDAY BUT CONFIDENCE TOO LOW TO WARRANT RAISING AN ADVISORY. OTHERWISE...NO CONCERNS WITH RESPECT TO WINDS AND SEAS UNTIL WEDNESDAY NIGHT/THURSDAY WHEN A NORTHEAST SURGE KICKS IN BEHIND THE FRONT. SMALL RISK FOR HEADLINES THURSDAY/THURSDAY...MAINLY FOR THE CHARLESTON COUNTY COASTAL WATERS AND OUTER GA WATERS. WILL KEEP AN EYE ON THE POTENTIAL FOR SOME SEA FOG TUESDAY INTO WEDNESDAY ACROSS THE NEARSHORE WATERS GIVEN THE POSSIBILITY OF HIGHER DEWPOINTS MOVING INTO THE AREA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS AFTERNOON FOR AMZ374. && $$ ST/JHP
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1135 AM CST SUN DEC 2 2012 .DISCUSSION... ISSUED 1022 AM CST SUN DEC 2 2012 AREA OF DENSE FOG IN WEST CENTRAL ILLINOIS HAS CREPT EASTWARD THE LAST COUPLE HOURS...INTO PARTS OF KNOX...FULTON AND SCHUYLER COUNTIES. COVERAGE AREA IS EXPECTED TO SHRINK OVER THE NEXT COUPLE OF HOURS...SO WILL HANDLE THIS WITH A SPECIAL WEATHER STATEMENT INSTEAD OF ISSUING A DENSE FOG ADVISORY. OTHERWISE...MAIN CONCERN IS WITH TIMING OF ANY CLEARING TODAY. HAVE BEEN SEEING SOME FILTERED SUNSHINE SOUTH OF I-72...BUT STRATOCUMULUS DECK TO THE NORTH WILL DROP A LITTLE FURTHER SOUTHEAST OVER THE NEXT FEW HOURS. RAP MODEL TRYING TO SHOW SOME CLEARING THIS AFTERNOON WEST OF THE ILLINOIS RIVER...BUT RECENT GRID UPDATES WERE NOT QUITE AS AGGRESSIVE ALTHOUGH STILL SHOWING SOME SUNSHINE BY MID AFTERNOON. THE EARLIER RAIN HAD DROPPED TO THE OHIO RIVER...SO REMOVED THE RAIN MENTION ACROSS THE EASTERN CWA. BOOSTED TEMPERATURES A COUPLE DEGREES AT MOST LOCATIONS. UPDATED GRIDS/ZONES HAVE BEEN SENT. GEELHART && .AVIATION... ISSUED 1135 AM CST SUN DEC 2 2012 CEILING/VISIBILITY ISSUES EXPECTED TO BE PREVALENT DURING A LARGE PORTION OF THE TAF PERIOD. OF IMMINENT CONCERN IS AREA OF LIFR CONDITIONS JUST WEST OF KPIA...WHERE CEILINGS DOWN TO 200 FEET IN DENSE FOG. LATEST OBS FROM KGBG/KMQB SHOWING RISING VISIBILITIES...BUT WILL KEEP MVFR CEILINGS AT KPIA/KBMI MUCH OF THE AFTERNOON. LINGERING CEILINGS BELOW 3000 FEET FURTHER SOUTH EXPECTED TO RISE OVER THE NEXT HOUR OR SO. MAIN QUESTION WILL BE WITH ANY REDEVELOPMENT OF LOW CLOUDS/DENSE FOG TONIGHT. LATEST MODEL GUIDANCE SUGGESTS ANY SUCH OCCURRENCE WOULD START AROUND KCMI/SOUTHWARD LATE THIS EVENING AND ADVECT TO THE NORTHWEST... AND HAVE SPREAD IFR CEILINGS OVER THE TAF SITES BY 08Z. HOWEVER... WINDS EXPECTED TO BE A BIT HIGHER THAN FIRST THOUGHT...AND THIS MAY HELP VISIBILITIES FROM COMPLETELY TANKING. USING THIS LINE OF THOUGHT...HAVE ADDED SOME TEMPO PERIODS OF 1/2 TO 3/4SM VISIBILITY INSTEAD OF PREVAILING VALUES. WINDS INCREASING TO AROUND 15 KNOTS LATE IN THE PERIOD WILL HELP THE LOWER VISIBILITIES COME UP QUICKLY...BUT SOUNDINGS SHOW CEILINGS MAY NOT RISE TO VFR RANGE UNTIL CLOSER TO 18Z. GEELHART && .PREV DISCUSSION... ISSUED 330 AM CST SUN DEC 2 2012 SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT A FAIRLY ACTIVE WEATHER PATTERN EXPECTED THIS WEEK WITH THREE WEATHER SYSTEMS TO IMPACT IL BRINGING RAIN CHANCES. THE 1ST SYSTEM IS WITH SCATTERED SHOWERS EXITING EASTERN IL INTO MID MORNING. THEN A STRONGER COLD FRONT TO MOVE SE THROUGH IL MONDAY NIGHT BRINGING A BETTER CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES EXPECTED THROUGH MONDAY AND MET/MAV GUIDANCE HIGHS CONTINUE TO BE NEAR RECORD HIGHS FOR DEC 3RD AND MONTH OF DECEMBER IN THE LOWER 70S. A 3RD FRONT SETS UP NEAR THE OHIO RIVER LATE THIS WEEK WITH OVERRUNNING RAIN CHANCES OVER CENTRAL AND ESPECIALLY SE IL. MET AND MAV GUIDANCE TEMPS SIMILAR THROUGH TUE AND STAYED CLOSE TO. RADAR MOSAIC SHOWS SCATTERED SHOWERS OVER EASTERN IL (EAST OF HIGHWAY 51) AND TRACKING ENE INTO INDIANA. A FEW THUNDERSTORMS WERE NOTED OVER SOUTHERN LAKE MI INTO SW LOWER MI. THESE AHEAD OF A WEAK FRONT OVER SE IA AND NW MO. SOUTH BREEZES (GUSTING AS HIGH AS 20-30 MPH EAST OF THE IL RIVER) AND CLOUDS AHEAD OF THIS FRONT BRINGING UNSEASONABLY MILD TEMPS IN THE MID 50S TO LOWER 60S EARLY THIS MORNING OVER CENTRAL/SE IL. MOIST DEWPOINTS IN THE LOWER 50S. WILL CONTINUE 20-40% CHANCE OF RAIN SHOWERS OVER EASTERN IL INTO MID MORNING AND ALSO CARRY PATCHY FOG OVER THE IL RIVER VALLEY. BUT FOG WILL BE MORE WIDESPREAD TO OUR NW OVER IA AND NORTHERN MO. NOT AS BREEZY TODAY AS WEAK FRONT MOVES EAST INTO IL AND CLOUDS TO DECREASE OVER THE IL RIVER VALLEY. HIGHS MOSTLY IN THE LOW TO MID 60S TODAY WITH SOME UPPER 60S OVER SW/SOUTHERN AREAS. RECORD HIGHS TODAY DEC 2 ARE IN THE UPPER 60S TO AROUND 70F. HAVE PATCHY FOG OVERNIGHT WITH MILD LOWS IN THE LOW TO MID 50S. EVEN WARMER MONDAY WITH NEAR RECORDS HIGHS OF 69-73F WITH SOUTHERN AREAS GETTING THE WARMEST. STRONGER SOUTH WINDS SET UP AGAIN MONDAY SIMILAR TO WHAT HAPPENED YESTERDAY/SATURDAY. HAVE 20-30% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS OVER THE IL RIVER VALLEY MONDAY AFTERNOON. BEST CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS IS MONDAY NIGHT STORM SYSTEM NEAR THE PACIFIC STATES BRINGS A STRONGER COLD FRONT SE THROUGH IL. CHANCE OF SHOWERS LINGERS TUE MORNING SE OF I-55 ESPECIALLY OVER SE IL THEN DRIER BY TUE AFTERNOON WITH CLOUDS DECREASING TUE FROM NW TO SE. MUCH COOLER HIGHS IN THE MID TO UPPER 50S WITH SE IL NEAR 60F...BUT STILL ABOVE NORMAL HIGHS FOR EARLY DECEMBER IN THE LOWER TO MIDDLE 40S. QUIET AND SEASONABLY COOL WEATHER EXPECTED TUE NIGHT THROUGH WED NIGHT AS HIGH PRESSURE SETTLES INTO THE REGION. HIGHS WED IN THE MID TO UPPER 40S...WITH SOME LOWER 50S SW AREAS. LONG TERM...THURSDAY THROUGH SATURDAY NIGHT EXTENDED MODELS HAVE TRENDED FURTHER SE WITH FRONTAL BOUNDARY NEAR THE OHIO RIVER LATE THIS WEEK WITH OVERRUNNING RAIN CHANCES INTO CENTRAL AND ESPECIALLY SE IL THU NIGHT INTO FRI NIGHT. ECMWF MODELS CONTINUES QPF INTO CENTRAL/SE IL INTO SAT THOUGH THINK THIS IS TOO FAR NORTH WITH MODELS TRENDING SOUTHWARD WITH THIS SYSTEM. MOST OF THE PRECIPITATION APPEARS TO FALL AS RAIN BUT COULD HAVE MIX DEVELOPING DURING FRI NIGHT ESPECIALLY NORTH OF I-70 AFTER MIDNIGHT IF PRECIP LINGERS THAT LONG. HIGHS IN THE LOW TO MID 50S THU GRADUALLY COOL CLOSER TO NORMAL BY NEXT WEEKEND. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1023 AM CST SUN DEC 2 2012 .DISCUSSION... ISSUED 1022 AM CST SUN DEC 2 2012 AREA OF DENSE FOG IN WEST CENTRAL ILLINOIS HAS CREPT EASTWARD THE LAST COUPLE HOURS...INTO PARTS OF KNOX...FULTON AND SCHUYLER COUNTIES. COVERAGE AREA IS EXPECTED TO SHRINK OVER THE NEXT COUPLE OF HOURS...SO WILL HANDLE THIS WITH A SPECIAL WEATHER STATEMENT INSTEAD OF ISSUING A DENSE FOG ADVISORY. OTHERWISE...MAIN CONCERN IS WITH TIMING OF ANY CLEARING TODAY. HAVE BEEN SEEING SOME FILTERED SUNSHINE SOUTH OF I-72...BUT STRATOCUMULUS DECK TO THE NORTH WILL DROP A LITTLE FURTHER SOUTHEAST OVER THE NEXT FEW HOURS. RAP MODEL TRYING TO SHOW SOME CLEARING THIS AFTERNOON WEST OF THE ILLINOIS RIVER...BUT RECENT GRID UPDATES WERE NOT QUITE AS AGGRESSIVE ALTHOUGH STILL SHOWING SOME SUNSHINE BY MID AFTERNOON. THE EARLIER RAIN HAD DROPPED TO THE OHIO RIVER...SO REMOVED THE RAIN MENTION ACROSS THE EASTERN CWA. BOOSTED TEMPERATURES A COUPLE DEGREES AT MOST LOCATIONS. UPDATED GRIDS/ZONES HAVE BEEN SENT. GEELHART && .AVIATION... ISSUED 556 AM CST SUN DEC 2 2012...FOR THE 12Z TAFS A BRIEF BREAK IN THE CLOUD COVER EXPECTED FOR SPI/DEC JUST AHEAD OF THE WEAK SURFACE FRONT MOVING ACROSS IL TODAY. LOW MOISTURE WILL INCREASE ALONG AND BEHIND THE TROUGH...BRINGING MVFR CEILINGS EVERYWHERE BY MID MORNING AND INTO THE AFTERNOON. BRIEF CLEARING MAY OCCUR THIS EVENING, BUT FOG AND LOW CLOUDS WILL RETURN BY MIDNIGHT IN MOST AREAS. LIFR IF NOT VLIFR FOG WILL BE POSSIBLE BY 09Z...BASED ON NAM FORECAST SOUNDINGS. WE INCLUDED A MENTION OF DENSE FOG LATE TONIGHT WITH THIS 12Z TAF ISSUANCE...DUE TO THE WIDESPREAD FOG BEHIND THE SYSTEM THIS MORNING IN IOWA AND N MISSOURI. CONFIDENCE IS INCREASING ABOUT A DENSE FOG EVENT BY SUNRISE TOMORROW. WINDS WILL SHIFT FROM SOUTHWEST TO WEST BEHIND THE WEAK SURFACE TROUGH...WITH WIND SPEED DECREASING BELOW 10KT AS IT DOES. LIGHT AND VARIABLE WINDS LATER TONIGHT WILL HELP WITH THE FOG FORMATION. SHIMON && .PREV DISCUSSION... ISSUED 330 AM CST SUN DEC 2 2012 SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT A FAIRLY ACTIVE WEATHER PATTERN EXPECTED THIS WEEK WITH THREE WEATHER SYSTEMS TO IMPACT IL BRINGING RAIN CHANCES. THE 1ST SYSTEM IS WITH SCATTERED SHOWERS EXITING EASTERN IL INTO MID MORNING. THEN A STRONGER COLD FRONT TO MOVE SE THROUGH IL MONDAY NIGHT BRINGING A BETTER CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES EXPECTED THROUGH MONDAY AND MET/MAV GUIDANCE HIGHS CONTINUE TO BE NEAR RECORD HIGHS FOR DEC 3RD AND MONTH OF DECEMBER IN THE LOWER 70S. A 3RD FRONT SETS UP NEAR THE OHIO RIVER LATE THIS WEEK WITH OVERRUNNING RAIN CHANCES OVER CENTRAL AND ESPECIALLY SE IL. MET AND MAV GUIDANCE TEMPS SIMILAR THROUGH TUE AND STAYED CLOSE TO. RADAR MOSAIC SHOWS SCATTERED SHOWERS OVER EASTERN IL (EAST OF HIGHWAY 51) AND TRACKING ENE INTO INDIANA. A FEW THUNDERSTORMS WERE NOTED OVER SOUTHERN LAKE MI INTO SW LOWER MI. THESE AHEAD OF A WEAK FRONT OVER SE IA AND NW MO. SOUTH BREEZES (GUSTING AS HIGH AS 20-30 MPH EAST OF THE IL RIVER) AND CLOUDS AHEAD OF THIS FRONT BRINGING UNSEASONABLY MILD TEMPS IN THE MID 50S TO LOWER 60S EARLY THIS MORNING OVER CENTRAL/SE IL. MOIST DEWPOINTS IN THE LOWER 50S. WILL CONTINUE 20-40% CHANCE OF RAIN SHOWERS OVER EASTERN IL INTO MID MORNING AND ALSO CARRY PATCHY FOG OVER THE IL RIVER VALLEY. BUT FOG WILL BE MORE WIDESPREAD TO OUR NW OVER IA AND NORTHERN MO. NOT AS BREEZY TODAY AS WEAK FRONT MOVES EAST INTO IL AND CLOUDS TO DECREASE OVER THE IL RIVER VALLEY. HIGHS MOSTLY IN THE LOW TO MID 60S TODAY WITH SOME UPPER 60S OVER SW/SOUTHERN AREAS. RECORD HIGHS TODAY DEC 2 ARE IN THE UPPER 60S TO AROUND 70F. HAVE PATCHY FOG OVERNIGHT WITH MILD LOWS IN THE LOW TO MID 50S. EVEN WARMER MONDAY WITH NEAR RECORDS HIGHS OF 69-73F WITH SOUTHERN AREAS GETTING THE WARMEST. STRONGER SOUTH WINDS SET UP AGAIN MONDAY SIMILAR TO WHAT HAPPENED YESTERDAY/SATURDAY. HAVE 20-30% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS OVER THE IL RIVER VALLEY MONDAY AFTERNOON. BEST CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS IS MONDAY NIGHT STORM SYSTEM NEAR THE PACIFIC STATES BRINGS A STRONGER COLD FRONT SE THROUGH IL. CHANCE OF SHOWERS LINGERS TUE MORNING SE OF I-55 ESPECIALLY OVER SE IL THEN DRIER BY TUE AFTERNOON WITH CLOUDS DECREASING TUE FROM NW TO SE. MUCH COOLER HIGHS IN THE MID TO UPPER 50S WITH SE IL NEAR 60F...BUT STILL ABOVE NORMAL HIGHS FOR EARLY DECEMBER IN THE LOWER TO MIDDLE 40S. QUIET AND SEASONABLY COOL WEATHER EXPECTED TUE NIGHT THROUGH WED NIGHT AS HIGH PRESSURE SETTLES INTO THE REGION. HIGHS WED IN THE MID TO UPPER 40S...WITH SOME LOWER 50S SW AREAS. LONG TERM...THURSDAY THROUGH SATURDAY NIGHT EXTENDED MODELS HAVE TRENDED FURTHER SE WITH FRONTAL BOUNDARY NEAR THE OHIO RIVER LATE THIS WEEK WITH OVERRUNNING RAIN CHANCES INTO CENTRAL AND ESPECIALLY SE IL THU NIGHT INTO FRI NIGHT. ECMWF MODELS CONTINUES QPF INTO CENTRAL/SE IL INTO SAT THOUGH THINK THIS IS TOO FAR NORTH WITH MODELS TRENDING SOUTHWARD WITH THIS SYSTEM. MOST OF THE PRECIPITATION APPEARS TO FALL AS RAIN BUT COULD HAVE MIX DEVELOPING DURING FRI NIGHT ESPECIALLY NORTH OF I-70 AFTER MIDNIGHT IF PRECIP LINGERS THAT LONG. HIGHS IN THE LOW TO MID 50S THU GRADUALLY COOL CLOSER TO NORMAL BY NEXT WEEKEND. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
215 PM EST SUN DEC 2 2012 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 1256 AM EST SUN DEC 2 2012 LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH NORTHEAST TODAY ALLOWING THE HIGH PRESSURE SYSTEM OVER THE CAROLINAS TO CONTINUE TO PROVIDE A UNSEASONABLY WARM FLOW OF SOUTHERLY AIR TO THE REGION. THIS PATTERN OF WARM SOUTHERLY WINDS IS EXPECTED TO CONTINUE UNTIL LATE TUESDAY NIGHT WHEN A STRONGER COLD FRONT IS EXPECTED TO PUSH ACROSS THE AREA...BRINGING OUR NEXT BEST CHANCE FOR RAIN SHOWERS AND PERHAPS A THUNDERSTORM. BEHIND THE FRONT...HIGH PRESSURE WILL BRING A RETURN TO MORE SEASONABLE TEMPERATURES AND DRY WEATHER WEDNESDAY AND THURSDAY. YET ANOTHER FRONTAL SYSTEM WILL BRING SHOWER CHANCES BACK BY THURSDAY NIGHT. && .NEAR TERM /REST OF TODAY/... ISSUED AT 944 AM EST SUN DEC 2 2012 WEAK UPPER WAVE IS MOVING EAST OF THE AREA AND ALLOWING RAIN TO COME TO AN END FROM WEST TO EAST. CLEARED RAIN OUT OF THE WESTERN TO SOME CENTRAL COUNTIES FOR THE REST OF THE DAY. MAINTAINED SOME SMALL CHANCES IN THE SOUTH AND EAST FOR THE NEXT FEW HOURS AND IN THE FAR SOUTHEAST INTO THE AFTERNOON WITH THE RAP /WHICH HAS A GOOD HANDLE ON THE CURRENT AREA OF PRECIPITATION/ SHOWING SOME POTENTIAL FOR REDEVELOPMENT DOWN THERE WITH CONTINUED ISENTROPIC LIFT. THIS LIFT SHOULD KEEP SKIES CLOUDY TO MOSTLY CLOUDY OVER THE ENTIRE AREA TODAY AS WELL WITH THE POSSIBILITY OF A FEW PEAKS OF SUNSHINE HERE AND THERE ACROSS THE WESTERN COUNTIES BUT EXPECT THIS TO FILL BACK IN. WITH EXPECTED CLOUD COVER AND STEADY 850 MB TEMPERATURES LOWERED HIGHS A FEW DEGREES IN THE CENTRAL AND EASTERN COUNTIES SO LOW 60S EXPECTED THERE WITH MIDDLE 60S STILL POSSIBLE IN THE WEST AND SOUTHWEST. WITHIN THE LOW CHANCE OF RAIN SHOWERS TODAY ALSO CONTINUED TO INCLUDE ISOLATED THUNDERSTORMS WITH ELEVATED INSTABILITY STILL AVAILABLE AND A FEW STRIKES SHOWING UP THIS MORNING WITHIN THE SHOWER BANDS. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 1256 AM EST SUN DEC 2 2012 MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE TEMPS UNTIL LATE MONDAY NIGHT/EARLY TUESDAY AS WHICH TIME THE FOCUS WILL BE POPS AS A STRONGER COLD FRONT PUSHES ACROSS THE STATE. MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND WILL USE A BLEND. LITTLE CHANGE IN THE PATTERN FOR TONIGHT AND MONDAY. ALOFT THE GFS AND NAM BOTH ALLOW RIDGING TO DEVELOP DURING THIS TIME. SURFACE FEATURE REMAIN IN PLACE...KEEPING THE WARM AIR ADVECTION AND SOUTHERLY WINDS IN PLACE. MEANWHILE TIME HEIGHT SECTIONS AND FORECAST SOUNDINGS ALSO CONTINUE TO KEEP RH/S HIGH IN THE LOWER LEVELS. THUS WILL AIM FOR PERSISTENCE IN THE FORECAST HERE...LOOKING FOR MOSTLY CLOUDY...AND WARM NIGHTS AND DAYS . WILL CONTINUE TO TREND BOTH LOWS AND HIGHS WARMER THAN GUIDANCE AS THAT HAS BEEN THE RESULT IN THIS PATTERN RECENTLY. LATE ON MONDAY NIGHT BOTH THE GFS AND NAM SHOW A STRONGER COLD FRONT PUSHING THROUGH THE AREA WITH BETTER DYNAMICS ALOFT. THE 300K GFS ISENTROPIC SURFACE IS MARGINAL...HOWEVER AN AXIS OF MOISTURE IS PRESENT ALONG AND AHEAD OF THE FRONT AS SPECIFIC HUMIDITIES PUSH OVER 5 G/KG. FORECAST SOUNDINGS SHOW DEEP SATURATION AVAILABLE TOWARD 12Z TUESDAY. Q VECTORS SHOW GOOD LOWER LEVEL CONVERGENCE. GIVEN THE EXPECTED CHANGE IN AIR MASS WILL TREND POPS AT OR ABOVE MAVMOS. ONLY THE LACK OF ISENTROPIC FORCING IS HOLDING ME BACK FROM RAISING POPS EVEN HIGHER. GIVEN THE EXPECTED RAIN AND CLOUDS AND WARM AIR ADVECTION AHEAD OF THE FRONT WILL TREND LOWS ON MONDAY NIGHT WARMER THAN MAVMOS. STEADY OR SLOWLY FALLING TEMPS ARE EXPECTED ON TUESDAY AS THE COLD FRONT LOOKS TO BE ON THE IND DOORSTEP NEAR 12Z. THE FRONT WILL QUICKLY PROGRESSES EAST AND RESULT IN SLOWLY FALLING OR STEADY TEMPS THROUGH MUCH OF THE DAY. MAY NEED TO KEEP SOME POPS DURING THE AM HOURS TO ACCOUNT FOR ANY LINGERING PRECIP NEAR THE FRONT AND FOR ANY TIMING DIFFERENCES THAT OCCUR IN THE MODELS OVER THE NEXT FEW RUNS. THUS WILL STICK CLOSE WITH THE MAVMOS POPS...BUT TREND TOWARD DRY WX QUICKLY BY 18Z TUESDAY AS MUCH DRIER AIR ARRIVES IN THE AREA ASSOCIATED WITH THE INCOMING HIGH PRESSURE SYSTEM. FURTHERMORE ALL FORCING SHOULD BE LONG GONE TO THE EAST BY 18Z. DRY WEATHER IS EXPECTED ON TUESDAY NIGHT AS THE HIGH PRESSURE SYSTEM SETTLES ACROSS THE AREA. FORECAST SOUNDINGS DRY OUT DRAMATICALLY AS THE LOWER LEVEL FLOW BECOMES NORTHERLY AND COLD AIR ADVECTION SET UP IS ON. WILL TREND COOLER THAN MEXMOS LOWS FOR TUESDAY NIGHT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ISSUED AT 215 PM EST SUN DEC 2 2012 THE MAIN CHALLENGE IN THE LONG TERM WILL BE TIMING A COLD FRONT THAT WILL BRING MORE SHOWERS TO CENTRAL INDIANA LATE IN THE WEEKEND. THE 12Z CANADIAN SEEMS TO BE THE OUTLIER IN QUICKLY MOVING A COLD FRONT SOUTHEAST ACROSS CENTRAL INDIANA THURSDAY NIGHT AND THEN BUILDING HIGH PRESSURE IN ON FRIDAY. THE 00Z ECMWF...AND 12Z GEFS AND GFS ARE MUCH SLOWER MOVING THE FRONT THROUGH ON FRIDAY. THEY ALSO HAVE THE FRONT STALL NEAR THE OHIO RIVER FRIDAY NIGHT. THEN...THE 12Z GEFS AND GFS DIFFER AS THEY BRING THE FRONT BACK NORTH ACROSS CENTRAL INDIANA ON SUNDAY...WHILE THE EURO MOVES IT INTO THE APPALACHIANS. SO...PREFER THE 00Z ECMWF AND 12Z GEFS AND GFS WHICH SUGGESTS SHOWER CHANCES THROUGH AT LEAST SATURDAY. THEN...WITH LOW CONDIDENCE IN WHICH AMONG THE 00Z EURO AND 12Z GEFS AND GFS WILL VERIFY BETTER...WILL ACCEPT THE REGIONAL INITIALIZATION WHICH HAS SMALL POPS SUNDAY. TEMPERATURES FOR SUNDAY WILL ALSO BE PROBLEMATIC DEPENDING ON WHERE THE FRONT LIES...AND FOR NOW WILL JUST ACCEPT REGIONAL NUMBERS. OTHERWISE...REGIONAL NUMBERS LOOK OK STARTING OUT AROUND NORMAL ON THURSDAY UNDER HIGH PRESSURE AND THEN BECOMING A LITTLE ABOVE NORMAL IN SOUTHWEST FLOW AHEAD OF THE FRONT ON THURSDAY. INITIALIZATION FOR THE REST OF THE PERIOD LOOKS OK TOO. && .AVIATION /DISCUSSION FOR THE 02/18Z TAF ISSUANCE/... ISSUED AT 1130 AM EST SUN DEC 2 2012 CEILINGS ARE TRENDING MVFR AND EXPECT THEM TO BE MOSTLY MVFR THROUGH THE TAF PERIOD AS LOW LEVEL MOISTURE HANGS AROUND. WOULD NOT RULE OUT LOWER STRATUS OR FOG TONIGHT WITH RECENT RAINS PER MOS...BUT NOT CONFIDENT ENOUGH TO ADD AT THIS TIME. THE SHOWERS SHOULD BE OVER. WINDS WILL BE SOUTHWEST AROUND 12 KNOTS WITH OCCASIONAL GUSTS TO 18 KNOTS PER NAM BUFKIT. LAF WILL PROBABLY NOT SEE ANY GUSTS WITH A WEAKER SURFACE GRADIENT THERE. THE OTHER SITES WILL ALSO DROP BELOW 10 KNOTS AFTER 21Z AS THE GRADIENT CONTINUES TO WEAKEN. HOWEVER...WINDS WILL PICK UP AGAIN AFTER 14Z TOMORROW AS THE GRADIENT STRENGTHENS ONCE MORE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL BECOME SOUTH NEAR 15Z KNOTS WITH GUSTS TO 20 KNOTS OR MORE. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...PUMA NEAR TERM...CP SHORT TERM...PUMA LONG TERM....MK AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1130 AM EST SUN DEC 2 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 1256 AM EST SUN DEC 2 2012 LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH NORTHEAST TODAY ALLOWING THE HIGH PRESSURE SYSTEM OVER THE CAROLINAS TO CONTINUE TO PROVIDE A UNSEASONABLY WARM FLOW OF SOUTHERLY AIR TO THE REGION. THIS PATTERN OF WARM SOUTHERLY WINDS IS EXPECTED TO CONTINUE UNTIL LATE TUESDAY NIGHT WHEN A STRONGER COLD FRONT IS EXPECTED TO PUSH ACROSS THE AREA...BRINGING OUR NEXT BEST CHANCE FOR RAIN SHOWERS AND PERHAPS A THUNDERSTORM. BEHIND THE FRONT...HIGH PRESSURE WILL BRING A RETURN TO MORE SEASONABLE TEMPERATURES AND DRY WEATHER WEDNESDAY AND THURSDAY. YET ANOTHER FRONTAL SYSTEM WILL BRING SHOWER CHANCES BACK BY THURSDAY NIGHT. && .NEAR TERM /REST OF TODAY/... ISSUED AT 944 AM EST SUN DEC 2 2012 WEAK UPPER WAVE IS MOVING EAST OF THE AREA AND ALLOWING RAIN TO COME TO AN END FROM WEST TO EAST. CLEARED RAIN OUT OF THE WESTERN TO SOME CENTRAL COUNTIES FOR THE REST OF THE DAY. MAINTAINED SOME SMALL CHANCES IN THE SOUTH AND EAST FOR THE NEXT FEW HOURS AND IN THE FAR SOUTHEAST INTO THE AFTERNOON WITH THE RAP /WHICH HAS A GOOD HANDLE ON THE CURRENT AREA OF PRECIPITATION/ SHOWING SOME POTENTIAL FOR REDEVELOPMENT DOWN THERE WITH CONTINUED ISENTROPIC LIFT. THIS LIFT SHOULD KEEP SKIES CLOUDY TO MOSTLY CLOUDY OVER THE ENTIRE AREA TODAY AS WELL WITH THE POSSIBILITY OF A FEW PEAKS OF SUNSHINE HERE AND THERE ACROSS THE WESTERN COUNTIES BUT EXPECT THIS TO FILL BACK IN. WITH EXPECTED CLOUD COVER AND STEADY 850 MB TEMPERATURES LOWERED HIGHS A FEW DEGREES IN THE CENTRAL AND EASTERN COUNTIES SO LOW 60S EXPECTED THERE WITH MIDDLE 60S STILL POSSIBLE IN THE WEST AND SOUTHWEST. WITHIN THE LOW CHANCE OF RAIN SHOWERS TODAY ALSO CONTINUED TO INCLUDE ISOLATED THUNDERSTORMS WITH ELEVATED INSTABILITY STILL AVAILABLE AND A FEW STRIKES SHOWING UP THIS MORNING WITHIN THE SHOWER BANDS. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 1256 AM EST SUN DEC 2 2012 MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE TEMPS UNTIL LATE MONDAY NIGHT/EARLY TUESDAY AS WHICH TIME THE FOCUS WILL BE POPS AS A STRONGER COLD FRONT PUSHES ACROSS THE STATE. MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND WILL USE A BLEND. LITTLE CHANGE IN THE PATTERN FOR TONIGHT AND MONDAY. ALOFT THE GFS AND NAM BOTH ALLOW RIDGING TO DEVELOP DURING THIS TIME. SURFACE FEATURE REMAIN IN PLACE...KEEPING THE WARM AIR ADVECTION AND SOUTHERLY WINDS IN PLACE. MEANWHILE TIME HEIGHT SECTIONS AND FORECAST SOUNDINGS ALSO CONTINUE TO KEEP RH/S HIGH IN THE LOWER LEVELS. THUS WILL AIM FOR PERSISTENCE IN THE FORECAST HERE...LOOKING FOR MOSTLY CLOUDY...AND WARM NIGHTS AND DAYS . WILL CONTINUE TO TREND BOTH LOWS AND HIGHS WARMER THAN GUIDANCE AS THAT HAS BEEN THE RESULT IN THIS PATTERN RECENTLY. LATE ON MONDAY NIGHT BOTH THE GFS AND NAM SHOW A STRONGER COLD FRONT PUSHING THROUGH THE AREA WITH BETTER DYNAMICS ALOFT. THE 300K GFS ISENTROPIC SURFACE IS MARGINAL...HOWEVER AN AXIS OF MOISTURE IS PRESENT ALONG AND AHEAD OF THE FRONT AS SPECIFIC HUMIDITIES PUSH OVER 5 G/KG. FORECAST SOUNDINGS SHOW DEEP SATURATION AVAILABLE TOWARD 12Z TUESDAY. Q VECTORS SHOW GOOD LOWER LEVEL CONVERGENCE. GIVEN THE EXPECTED CHANGE IN AIR MASS WILL TREND POPS AT OR ABOVE MAVMOS. ONLY THE LACK OF ISENTROPIC FORCING IS HOLDING ME BACK FROM RAISING POPS EVEN HIGHER. GIVEN THE EXPECTED RAIN AND CLOUDS AND WARM AIR ADVECTION AHEAD OF THE FRONT WILL TREND LOWS ON MONDAY NIGHT WARMER THAN MAVMOS. STEADY OR SLOWLY FALLING TEMPS ARE EXPECTED ON TUESDAY AS THE COLD FRONT LOOKS TO BE ON THE IND DOORSTEP NEAR 12Z. THE FRONT WILL QUICKLY PROGRESSES EAST AND RESULT IN SLOWLY FALLING OR STEADY TEMPS THROUGH MUCH OF THE DAY. MAY NEED TO KEEP SOME POPS DURING THE AM HOURS TO ACCOUNT FOR ANY LINGERING PRECIP NEAR THE FRONT AND FOR ANY TIMING DIFFERENCES THAT OCCUR IN THE MODELS OVER THE NEXT FEW RUNS. THUS WILL STICK CLOSE WITH THE MAVMOS POPS...BUT TREND TOWARD DRY WX QUICKLY BY 18Z TUESDAY AS MUCH DRIER AIR ARRIVES IN THE AREA ASSOCIATED WITH THE INCOMING HIGH PRESSURE SYSTEM. FURTHERMORE ALL FORCING SHOULD BE LONG GONE TO THE EAST BY 18Z. DRY WEATHER IS EXPECTED ON TUESDAY NIGHT AS THE HIGH PRESSURE SYSTEM SETTLES ACROSS THE AREA. FORECAST SOUNDINGS DRY OUT DRAMATICALLY AS THE LOWER LEVEL FLOW BECOMES NORTHERLY AND COLD AIR ADVECTION SET UP IS ON. WILL TREND COOLER THAN MEXMOS LOWS FOR TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ISSUED AT 329 AM EST SUN DEC 2 2012 THE LONG TERM PERIOD WILL START OUT DRY WITH HIGH PRESSURE IN PLACE. HOWEVER...THE NEXT UPPER LEVEL SYSTEM AND ASSOCIATED COLD FRONT ARE PROGGED FOR THURSDAY NIGHT/FRIDAY. AT THIS TIME...INSTABILITY IS STILL LACKING...SO WILL NOT INCLUDE MENTION OF THUNDER. LATEST INITIALIZATION CONTINUES TO BRING IN ABOVE NORMAL TEMPS...SO DO NOT EXPECT ANY TYPE OF WINTRY PRECIP. MODELS CONTINUE TO SHOW VARIABILITY...SO WILL NOT DEVIATE THIS FAR OUT. && .AVIATION /DISCUSSION FOR THE 02/18Z TAF ISSUANCE/... ISSUED AT 1130 AM EST SUN DEC 2 2012 CEILINGS ARE TRENDING MVFR AND EXPECT THEM TO BE MOSTLY MVFR THROUGH THE TAF PERIOD AS LOW LEVEL MOISTURE HANGS AROUND. WOULD NOT RULE OUT LOWER STRATUS OR FOG TONIGHT WITH RECENT RAINS PER MOS...BUT NOT CONFIDENT ENOUGH TO ADD AT THIS TIME. THE SHOWERS SHOULD BE OVER. WINDS WILL BE SOUTHWEST AROUND 12 KNOTS WITH OCCASIONAL GUSTS TO 18 KNOTS PER NAM BUFKIT. LAF WILL PROBABLY NOT SEE ANY GUSTS WITH A WEAKER SURFACE GRADIENT THERE. THE OTHER SITES WILL ALSO DROP BELOW 10 KNOTS AFTER 21Z AS THE GRADIENT CONTINUES TO WEAKEN. HOWEVER...WINDS WILL PICK UP AGAIN AFTER 14Z TOMORROW AS THE GRADIENT STRENGTHENS ONCE MORE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL BECOME SOUTH NEAR 15Z KNOTS WITH GUSTS TO 20 KNOTS OR MORE. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...PUMA NEAR TERM...CP SHORT TERM...PUMA LONG TERM....TDUD AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
953 AM EST SUN DEC 2 2012 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 1256 AM EST SUN DEC 2 2012 LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH NORTHEAST TODAY ALLOWING THE HIGH PRESSURE SYSTEM OVER THE CAROLINAS TO CONTINUE TO PROVIDE A UNSEASONABLY WARM FLOW OF SOUTHERLY AIR TO THE REGION. THIS PATTERN OF WARM SOUTHERLY WINDS IS EXPECTED TO CONTINUE UNTIL LATE TUESDAY NIGHT WHEN A STRONGER COLD FRONT IS EXPECTED TO PUSH ACROSS THE AREA...BRINGING OUR NEXT BEST CHANCE FOR RAIN SHOWERS AND PERHAPS A THUNDERSTORM. BEHIND THE FRONT...HIGH PRESSURE WILL BRING A RETURN TO MORE SEASONABLE TEMPERATURES AND DRY WEATHER WEDNESDAY AND THURSDAY. YET ANOTHER FRONTAL SYSTEM WILL BRING SHOWER CHANCES BACK BY THURSDAY NIGHT. && .NEAR TERM /REST OF TODAY/... ISSUED AT 944 AM EST SUN DEC 2 2012 WEAK UPPER WAVE IS MOVING EAST OF THE AREA AND ALLOWING RAIN TO COME TO AN END FROM WEST TO EAST. CLEARED RAIN OUT OF THE WESTERN TO SOME CENTRAL COUNTIES FOR THE REST OF THE DAY. MAINTAINED SOME SMALL CHANCES IN THE SOUTH AND EAST FOR THE NEXT FEW HOURS AND IN THE FAR SOUTHEAST INTO THE AFTERNOON WITH THE RAP /WHICH HAS A GOOD HANDLE ON THE CURRENT AREA OF PRECIPITATION/ SHOWING SOME POTENTIAL FOR REDEVELOPMENT DOWN THERE WITH CONTINUED ISENTROPIC LIFT. THIS LIFT SHOULD KEEP SKIES CLOUDY TO MOSTLY CLOUDY OVER THE ENTIRE AREA TODAY AS WELL WITH THE POSSIBILITY OF A FEW PEAKS OF SUNSHINE HERE AND THERE ACROSS THE WESTERN COUNTIES BUT EXPECT THIS TO FILL BACK IN. WITH EXPECTED CLOUD COVER AND STEADY 850 MB TEMPERATURES LOWERED HIGHS A FEW DEGREES IN THE CENTRAL AND EASTERN COUNTIES SO LOW 60S EXPECTED THERE WITH MIDDLE 60S STILL POSSIBLE IN THE WEST AND SOUTHWEST. WITHIN THE LOW CHANCE OF RAIN SHOWERS TODAY ALSO CONTINUED TO INCLUDE ISOLATED THUNDERSTORMS WITH ELEVATED INSTABILITY STILL AVAILABLE AND A FEW STRIKES SHOWING UP THIS MORNING WITHIN THE SHOWER BANDS. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 1256 AM EST SUN DEC 2 2012 MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE TEMPS UNTIL LATE MONDAY NIGHT/EARLY TUESDAY AS WHICH TIME THE FOCUS WILL BE POPS AS A STRONGER COLD FRONT PUSHES ACROSS THE STATE. MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND WILL USE A BLEND. LITTLE CHANGE IN THE PATTERN FOR TONIGHT AND MONDAY. ALOFT THE GFS AND NAM BOTH ALLOW RIDGING TO DEVELOP DURING THIS TIME. SURFACE FEATURE REMAIN IN PLACE...KEEPING THE WARM AIR ADVECTION AND SOUTHERLY WINDS IN PLACE. MEANWHILE TIME HEIGHT SECTIONS AND FORECAST SOUNDINGS ALSO CONTINUE TO KEEP RH/S HIGH IN THE LOWER LEVELS. THUS WILL AIM FOR PERSISTENCE IN THE FORECAST HERE...LOOKING FOR MOSTLY CLOUDY...AND WARM NIGHTS AND DAYS . WILL CONTINUE TO TREND BOTH LOWS AND HIGHS WARMER THAN GUIDANCE AS THAT HAS BEEN THE RESULT IN THIS PATTERN RECENTLY. LATE ON MONDAY NIGHT BOTH THE GFS AND NAM SHOW A STRONGER COLD FRONT PUSHING THROUGH THE AREA WITH BETTER DYNAMICS ALOFT. THE 300K GFS ISENTROPIC SURFACE IS MARGINAL...HOWEVER AN AXIS OF MOISTURE IS PRESENT ALONG AND AHEAD OF THE FRONT AS SPECIFIC HUMIDITIES PUSH OVER 5 G/KG. FORECAST SOUNDINGS SHOW DEEP SATURATION AVAILABLE TOWARD 12Z TUESDAY. Q VECTORS SHOW GOOD LOWER LEVEL CONVERGENCE. GIVEN THE EXPECTED CHANGE IN AIR MASS WILL TREND POPS AT OR ABOVE MAVMOS. ONLY THE LACK OF ISENTROPIC FORCING IS HOLDING ME BACK FROM RAISING POPS EVEN HIGHER. GIVEN THE EXPECTED RAIN AND CLOUDS AND WARM AIR ADVECTION AHEAD OF THE FRONT WILL TREND LOWS ON MONDAY NIGHT WARMER THAN MAVMOS. STEADY OR SLOWLY FALLING TEMPS ARE EXPECTED ON TUESDAY AS THE COLD FRONT LOOKS TO BE ON THE IND DOORSTEP NEAR 12Z. THE FRONT WILL QUICKLY PROGRESSES EAST AND RESULT IN SLOWLY FALLING OR STEADY TEMPS THROUGH MUCH OF THE DAY. MAY NEED TO KEEP SOME POPS DURING THE AM HOURS TO ACCOUNT FOR ANY LINGERING PRECIP NEAR THE FRONT AND FOR ANY TIMING DIFFERENCES THAT OCCUR IN THE MODELS OVER THE NEXT FEW RUNS. THUS WILL STICK CLOSE WITH THE MAVMOS POPS...BUT TREND TOWARD DRY WX QUICKLY BY 18Z TUESDAY AS MUCH DRIER AIR ARRIVES IN THE AREA ASSOCIATED WITH THE INCOMING HIGH PRESSURE SYSTEM. FURTHERMORE ALL FORCING SHOULD BE LONG GONE TO THE EAST BY 18Z. DRY WEATHER IS EXPECTED ON TUESDAY NIGHT AS THE HIGH PRESSURE SYSTEM SETTLES ACROSS THE AREA. FORECAST SOUNDINGS DRY OUT DRAMATICALLY AS THE LOWER LEVEL FLOW BECOMES NORTHERLY AND COLD AIR ADVECTION SET UP IS ON. WILL TREND COOLER THAN MEXMOS LOWS FOR TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ISSUED AT 329 AM EST SUN DEC 2 2012 THE LONG TERM PERIOD WILL START OUT DRY WITH HIGH PRESSURE IN PLACE. HOWEVER...THE NEXT UPPER LEVEL SYSTEM AND ASSOCIATED COLD FRONT ARE PROGGED FOR THURSDAY NIGHT/FRIDAY. AT THIS TIME...INSTABILITY IS STILL LACKING...SO WILL NOT INCLUDE MENTION OF THUNDER. LATEST INITIALIZATION CONTINUES TO BRING IN ABOVE NORMAL TEMPS...SO DO NOT EXPECT ANY TYPE OF WINTRY PRECIP. MODELS CONTINUE TO SHOW VARIABILITY...SO WILL NOT DEVIATE THIS FAR OUT. && .AVIATION /DISCUSSION FOR THE 02/15Z TAF UPDATES/... ISSUED AT 925 AM EST SUN DEC 2 2012 CEILINGS HAVE BEEN TRENDING BORDERLINE VFR AND MVFR AND MOS SUGGESTS MVFR OR WORSE...SO WENT WITH MVFR TODAY...AND PULLED THE VICINITY SHOWERS BASED ON RADAR TRENDS. PREVIOUS DISCUSSION FOLLOWS... MVFR/VFR HAVE BEEN THE PREVAILING CONDITIONS OVER THE LAST FEW HOURS AS RAIN SHOWERS PASS THROUGH TAF SITES. MOST RAINFALL HAS ALREADY MOVED EAST OF KLAF/KHUF/KIND...BUT DEEP LOW LEVEL MOISTURE IN ITS WAKE WILL RESULT IN A PERSISTENT LOW STRATOCU DECK AND MVFR CONDITIONS FOR THE REMAINDER OF TODAY. AS WINDS WEAKEN AFTER SUNSET TONIGHT AND LOW LEVEL MOISTURE REMAINS IN PLACE...CONDITIONS WILL WORSEN TO WIDESPREAD IFR CATEGORY AT ALL TAF SITES DUE TO FOG DEVELOPMENT. POOR FLYING CONDITIONS WILL PERSIST THROUGH TONIGHT. LOW LEVEL WIND SHEAR IS STILL OVER THE NEXT FEW HOURS WITH 45-50KT WINDS AT 1500 FT. THIS THREAT WILL SUBSIDE BY MID MORNING WHEN LOW LEVEL JET SHIFTS EAST. AT THE SURFACE...WINDS WILL BE S/SW AT 10 TO 12 KTS TODAY AND THEN TAPER OFF THIS EVENING. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...PUMA NEAR TERM...CP SHORT TERM...PUMA LONG TERM....TDUD AVIATION...TDUD/MK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
507 PM CST MON DEC 3 2012 .UPDATE... A FORECAST UPDATE WAS SENT EARLY THIS PAST HOUR TO REFLECT A MUCH LESS COVERAGE OF SHOWERS AND SHALLOW THUNDERSTORMS/CONVECTION. THE EAST REMAINS THE MOST LIKELY AREA TO RECEIVE MEASURABLE RAIN...BUT LOCATIONS WEST OF PRINCETON TO STERLING ARE LIKELY TO REMAIN WITH TRACE AMOUNTS. AS FAR AS STRONG STORMS...WINDS ARE VEERING TO THE SOUTHWEST...REDUCING SHEAR AT LOW LEVELS...THIS IS TRUE EXCEPT FOR BUREAU AND PUTNAM COUNTIES...BUT BY THE TIME STORMS REACH THERE...THEY MAY VEER AS WELL. WE REMAIN WATCH FULL...BUT FEEL THE THREAT FOR A SEVERE EVENT IS VERY LOW AND CONFINED TO THE NEXT 1 HOUR...IN THE FAR EAST. ERVIN && .PREV DISCUSSION... /ISSUED 308 PM CST MON DEC 3 2012/ SYNOPSIS... A COLD FRONT WAS PUSHING INTO CENTRAL IOWA WITH SOUTHERLY WINDS TRANSPORTING UNSEASONABLY WARM AND HUMID AIR INTO THE DVN CWA. RECORD HIGHS HAVE ALREADY BEEN SET OR TIED FOR DECEMBER 3 AT ALL MAJOR CLIMATE SITES. TEMPERATURES WERE ALSO NEARING THE ALL-TIME RECORD HIGHS FOR DECEMBER. CURRENT READINGS WERE IN THE MID 60S TO LOWER 70S WITH DEW POINTS AROUND 60. SPC MESO ANALYSIS INDICATED SBCAPES WERE 500 J/KG AND EFFECTIVE BULK SHEAR WAS 45 KTS EAST OF THE MS RIVER. EXTENSIVE LOW CLOUDS WERE OVER THE CWA BUT SOME BREAKS NOTED ON VISIBLE SATELLITE PICTURES. ELSEWHERE BEHIND THE FRONT TEMPERATURES WERE IN THE 50S WITH DEW POINTS IN THE TEENS...ALONG WITH SUNNY SKIES. HAASE SHORT TERM...TONIGHT AND TUESDAY... FORECAST FOCUS ON CONVECTIVE TRENDS LATE THIS AFTERNOON/EARLY THIS EVENING WITH COLD FRONT. TONIGHT...LOW CLOUDS PUTTING A DAMPER ON THE CONVECTIVE THREAT BUT WILL STILL MENTION SHOWERS LIKELY AND ISOLATED THUNDERSTORMS FROM MAINLY ABOUT THE MS RIVER ON EAST INTO THIS EVENING. HRRR MESO MODEL SEEMS REASONABLE. THE COLD FRONT SHOULD BE NEAR THE MS RIVER ABOUT 6 PM AND WILL HAVE MOVED THROUGH ALL OF THE CWA BEFORE MIDNIGHT SO WILL BE DRY AFTER MIDNIGHT. SKIES WILL CLEAR LATER TONIGHT AS SUBSIDENCE BEHIND UPPER TROUGH SWINGS THROUGH. WILL BE COLDER WITH MIN TEMPS IN THE MID 30S NW TO MID 40S SE. TUESDAY...HIGH PRESSURE BUILDS INTO THE CWA WITH SUNNY SKIES AND COOLER TEMPERATURES...BUT STILL WELL ABOVE NORMAL FOR EARLY DECEMBER. EXPECT AFTERNOON READINGS IN THE 50S ACROSS THE CWA. HAASE LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY... ZONAL UPPER LEVEL FLOW TO CONTINUE THE WARMER THAN NORMAL TEMPERATURES THROUGH THE WORKWEEK WITH PRECIPITATION CHANCES FOCUSED ON A COLD FRONTAL PASSAGE THURSDAY. THE POTENTIAL FOR MUCH COLDER TEMPERATURES AND POSSIBLE WINTRY PRECIPITATION IS STARTING TO LOOK MORE LIKELY WITH THE ARRIVAL OF A MORE DYNAMIC PATTERN OVER THE WEEKEND INTO EARLY NEXT WEEK. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...HIGH PRESSURE DROPPING SOUTHEAST OUT OF THE NORTHERN PLAINS WILL BRING A COLDER AIRMASS INTO THE REGION TUESDAY NIGHT. CLEAR SKIES...LIGHT WINDS...AND 850 MB TEMPERATURES IN THE LOW SINGLE DIGITS SUPPORT LOWS FROM THE MID 20S NORTH TO LOWER 30S SOUTH. WEDNESDAY WILL REMAIN RELATIVELY COOL COMPARED TO THE RECENT WARMTH AS LIGHT SOUTHEAST WINDS OUT OF THE DEPARTING HIGH LIMIT HIGHS TO THE UPPER 30S NORTH TO NEAR 50 IN THE FAR SOUTH. HIGH LEVEL CLOUD COVER WEDNESDAY WELL OUT AHEAD OF THE NEXT FAST MOVING SHORTWAVE WILL HOLD MINS TO THE 30S. THE FASTER ECMWF AND GEM TIMING OF THURSDAY EVENING/S COLD FRONTAL PASSAGE IS PREFERRED OVER THE SLOWER GFS IN THE FAST FLOW ALOFT. MODELS HAVE BACKED OFF SOME ON THE EXTENT OF PREFRONTAL PRECIPITATION...AND HAVE FOLLOWED BY CONFINING LOW CHANCES FOR RAIN SHOWERS TO MAINLY THE AFTERNOON HOURS ACROSS THE NORTHWEST. OTHERWISE...IT WILL BE ANOTHER DAY OF BRISK SOUTHERLY WINDS...CLOUD COVER AND MILD TEMPERATURES AHEAD OF THE FRONT WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. FOLLOWING THE FASTER NON-GFS SOLUTIONS...THE FRONT SHOULD PUSH WELL SOUTHEAST BY FRIDAY MORNING...ALLOWING A DRY NORTH TO NORTHEAST LOW LEVEL FLOW OUT OF THE NEXT HIGH DROPPING INTO THE NORTHERN PLAINS. HOWEVER...DUE TO THE INPUT OF THE SLOWER...MORE NORTHERLY GFS FRONTAL SOLUTION...SLIGHT CHANCE POPS ARE CARRIED INTO THE FRIDAY PERIOD. TEMPERATURES WILL BE NOTICEABLY COOLER AS HIGHS RETURN TO THE 40S. SATURDAY THROUGH MONDAY...LATEST MODEL SOLUTIONS GENERALLY AGREE ON AN EVOLUTION TO A MORE AMPLIFIED UPPER LEVEL FLOW AS A BUILDING RIDGE IN THE EASTERN PACIFIC INDUCES A LONGWAVE TROUGH DOWNSTREAM IN THE WESTERN U.S. THIS SETS UP AN UPPER LEVEL SOUTHWEST FLOW OVER A STALLED FRONTAL BOUNDARY THROUGH THE MID MS VALLEY...FAVORABLE FOR MORE WINTRY TYPE SYSTEMS OVER THE LOCAL AREA. HOWEVER...DUE TO HIGH MODEL VARIABILITY FROM RUN TO RUN AND BETWEEN MODELS...CONFIDENCE IN DETAILS IN THESE PERIODS REMAINS LOW. OVER THE PAST FEW RUNS...THE ECMWF APPEARS TO HAVE THE BEST CONTINUITY WITH ITS MORE PHASED DEPICTION OF THE LEAD SHORTWAVES THAT COULD RESULT IN THE REGION/S FIRST WINTER STORM SYSTEM TRACKING FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT. THE 12Z GFS HAS A SIMILAR SURFACE LOW...ALTHOUGH HAS A SLIGHTLY FASTER AND MORE NORTHERLY TRACK. FOR NOW...THE BLENDED MODEL APPROACH WILL KEEP AN EXTENDED PERIOD OF SLIGHT TO LOW END CHANCE POPS FROM FRIDAY NIGHT THROUGH MONDAY...WHICH WILL LIKELY BE NARROWED DOWN IN LATER FORECASTS. ABOVE NORMAL TEMPERATURES ADVERTISED THROUGH THE WEEKEND COULD END UP SEVERAL CATEGORIES TOO HIGH...ESPECIALLY FROM SUNDAY INTO MONDAY. SHEETS AVIATION... VFR CONDS REMAINDER OF THIS AFTERNOON THROUGH TUESDAY. A COLD FRONT WILL MOVE THROUGH THE REGION AND SHOULD BE NEAR THE MISSISSIPPI RIVER BY 6 PM. ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THE FRONT WITH THE BEST CHANCE NEAR AND EAST OF THE MISSISSIPPI LATE THIS AFTERNOON AND EARLY THIS EVENING. WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT AND WILL BE GUSTY THROUGH THE EVENING HOURS. SKIES WILL CLEAR AND WINDS WILL DIMINISH AFTER MIDNIGHT. HIGH PRESSURE WILL BRING SKC ON TUESDAY WITH NORTHWEST WINDS AROUND 10 KNOTS. HAASE CLIMATE... RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGHS... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1214 PM CST SUN DEC 2 2012 .UPDATE... HAVE EXTENDED DENSE FOG ADVISORY UNTIL 19Z FOR FAR SOUTHEAST IA... NORTHEAST MO AND PORTIONS OF WEST CENTRAL IL. MAY STILL SEE SOME POCKETS OF DENSE FOG LINGER BEYOND BUT HOPEFULLY NOT WIDESPREAD ENOUGH TO NECESSITATE CONTINUING EXTENSION OF THE ADVISORY. ALSO... MADE ADJUSTMENTS TO HIGH TEMPS AND SKY COVER GRIDS BASED ON CURRENT TRENDS. && .AVIATION... STRATUS AND FOG HOLDING ON AT KBRL AND KMLI WITH IFR TO LIFR CONDITIONS. TRIED FOR SOME IMPROVEMENT AT BOTH SITES BY MID TO LATE AFTN... BUT PROBABLY NO BETTER THAN MVFR AT BEST. TNGT...EXPECT WIDESPREAD IFR/LIFR LOW CIGS AS LOW LEVEL FLOW BECOMES SOUTHERLY ADVECTING THE CLOUDS NORTHWARD THROUGH THE TERMINALS. ANTICIPATE FOG WITH AREAS OF DENSE FOG... BUT QUITE CHALLENGING ON HOW WIDESPREAD VLIFR VSBYS AS MODELS DO INDICATE INCREASING MSLP GRADIENT OVRNGT INTO MON AM AHEAD OF THE NEXT FRONT. HAVE ONLY DENSE FOG MENTION AT KBRL FOR NOW WHERE CONFIDENCE IS GREATEST BASED ON LIMITED IMPROVEMENT REST OF TDY... VERY SMALL TEMP/DEWPT SPREADS AND LIGHT WINDS. SOUTH WINDS AT 10-15 KTS WITH SOME GUSTS BY MID TO LATE MON AM SHOULD BRING IMPROVEMENT TO VSBYS... ALTHOUGH ANTICIPATE IFR TO LIFR CIGS TO LINGER. && .PREV DISCUSSION... /ISSUED 1016 AM CST SUN DEC 2 2012/ UPDATE... BASED ON OBSERVATIONS... SPOTTER REPORTS AND WEBCAMS... HAVE EXTENDED THE DENSE FOG ADVISORY UNTIL 18Z. ALSO ADDED A FEW COUNTIES OVER PORTIONS OF SOUTHEAST IA AND WEST CENTRAL IL. BESIDES FOG... SLOWED THE CLEARING TREND FOR PORTIONS OF SOUTHEAST IA... NORTHEAST MO AND WEST CENTRAL IL UNTIL MID TO LATE AFTN AND POTENTIAL FOR SOME AREAS TO REMAIN CLOUDY ALL DAY SOUTH WITH LIGHT WINDS/WEAK MIXING AND ABUNDANT MOISTURE. PREV DISCUSSION... /ISSUED 559 AM CST SUN DEC 2 2012/ UPDATE... THE LONE WEB CAM NEAR THE IA/MO BORDER INDICATES THICK FOG IN THE AREA. KMPZ VISIBILITY IS DOWN AS IS KIRK. THUS DENSE FOG IS OCCURRING IN VAN BUREN AND HENRY COUNTIES IN IOWA...AND PROBABLY IN SCOTLAND/CLARK COUNTIES IN MISSOURI AND THE WESTERN PART OF LEE COUNTY IN IOWA. THUS THE DENSE FOG ADVISORY WILL BE EXPANDED INTO THESE AREAS AND WILL ALSO BE EXTENDED 1 HOUR EVERYWHERE. A WEAK TROF IS MOVING THROUGH THE CENTRAL CWFA WHICH MAY BE PARTIALLY RESPONSIBLE FOR THE INCREASE IN DENSE FOG DOWN SOUTH. SATELLITE TRENDS CONTINUE TO SHOW STRONG SUBSIDENCE IN CENTRAL AND WESTERN IOWA WHICH IS JUST BEGINNING TO ENTER THE FAR NORTHWEST PART OF THE CWFA. FOR THE MOST PART...THE GENERAL TREND OF THE FCST LOOKS TO BE ON TRACK WITH CLEARING OCCURRING DURING THE DAY. ..08.. PREV DISCUSSION... /ISSUED 300 AM CST SUN DEC 2 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM ROUGHLY GREEN BAY BACK TO THE NEBRASKA/KANSAS BORDER. ANOTHER FRONT RAN FROM A LOW NEAR KSAW BACK TO AROUND KYKN. DEW POINTS OVER THE GREAT LAKES AND MIDWEST WERE IN THE 40S AND 50S WITH 30S IN THE PLAINS. SHORT TERM...TODAY AND TONIGHT THE IMMEDIATE CONCERN IS FOG POTENTIAL AND THE CURRENT HEADLINES. SATELLITE TRENDS SHOW GOOD SUBSIDENCE OVER NORTHWEST/WESTERN IOWA WHICH HAS ALLOWED A LARGE EXPANSE OF DENSE FOG TO FORM IN THE MOIST AIR. SAID FOG HAS EXPANDED EASTWARD IN THE LIGHT WINDS/CONVERGENCE TO INCLUDE ROUGHLY THE NORTHWEST THIRD OF THE CWFA. BASED ON CURRENT TRENDS WITH INPUT FROM THE RAP MODEL...THE CURRENT FOG HEADLINES LOOK OK. HOWEVER...GIVEN THE EXTREMELY WARM AND MOIST AIR OVER THE CWFA THERE IS REASONABLE POTENTIAL FOR PATCHY IF NOT LOCALIZED AREAS OF FOG DEVELOPING AHEAD OF THE CURRENT FOG HEADLINES ESPECIALLY IF CLEAR POCKETS DEVELOP IN THE LOW CLOUDS. THE OVERALL SUBSIDENCE INCREASES DURING THE DAY SO CLEARING IS EXPECTED FROM WEST TO EAST DURING THE DAY. GIVEN THE EXCEPTIONALLY MILD START...MAX TEMPERATURES WILL BE WELL ABOVE NORMAL FOR EARLY DECEMBER. RECORD HIGHS APPEAR DOUBTFUL BUT KBRL MAY BE CLOSE BASED ON PROJECTED MAX TEMPERATURES. A RECORD WARM LOW WILL NOT BE REALIZED AT KDBQ BUT COULD OCCUR AT KMLI. QUIET CONDITIONS WILL BE SEEN DURING THE EVENING ACROSS THE AREA. THE WARM TEMPERATURES COMBINED WITH LIGHT WINDS AND INITIALLY CLEAR OR NEARLY CLEAR SKIES SHOULD ALLOW PATCHY FOG TO DEVELOP BY LATE EVENING ACROSS THE NORTHEAST QUADRANT OF THE CWFA. AFTER MIDNIGHT...ANOTHER INFLUX OF MOISTURE WILL MOVE BACK INTO THE AREA WHICH SHOULD INCLUDE CONSIDERABLE LOW CLOUDS. PATCHY FOG SHOULD DEVELOP OVER MOST OF THE AREA. THE NORTHEAST QUADRANT OF THE CWFA WILL HAVE LIGHT WINDS AND CLEAR SKIES THE LONGEST SO THE FOG SHOULD BECOME MORE WIDESPREAD THERE. MIN TEMPERATURES TONIGHT WILL BE ABOVE THE NORMAL MAX TEMPERATURES. ..08.. LONG TERM...MONDAY THROUGH SATURDAY MODELS CONTINUE TO SHOW ZONAL FLOW OVER U.S. THROUGH MID WEEK WITH SOME AMPLIFICATION IN THE FLOW DEVELOPING LATE WEEK AS A BROAD H5 TROF FORMS OVER THE WESTERN AND CENTRAL U.S. IN THE NEAR TERM...RECORD OR NEAR RECORD WARMTH LOOKS ON TRACK FOR MONDAY WITH THE MODELS IN GOOD AGREEMENT MOVING UNSEASONABLY WARM AIR NORTH OUT OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AHEAD OF A COLD FRONT THAT SHOULD BE MOVING INTO THE CENTRAL IA BY MID DAY. H8 TEMPS IN THE 10C TO 15C RANGE ARE PROGGED TO BE OVER THE AREA MONDAY MORNING. A SURFACE WARM FRONT SHOULD BE NEAR THE IA/MO BORDER EARLY MONDAY AND WILL MOVE NORTH DURING THE DAY WITH SOUTH WINDS INCREASING INTO THE 15 TO 25 MPH IN THE WARM SECTOR. ADDING SOME UNCERTAINTY TO THE WARM UP WILL BE UNUSUALLY HIGH LOW LEVEL MOISTURE THAT WILL BE OVER AREA BY MONDAY MORNING. THE MOIST LOW LEVELS SHOULD RESULT IN STRATUS AS WELL AS SOME PATCHY DRIZZLE AND FOG DURING THE MORNING WHICH IS EXPECTED TO MIX OUT SOME DURING THE DAY WITH INCREASING SOUTH WINDS. SOME MOS GUIDANCE INCLUDING THE MET AND ECMWF MOS IS SUGGESTING TEMPERATURES IN THE LOW 70S SOUTH TO MID 60S NORTH FOR HIGHS. HOWEVER HAVE KEPT A DEGREE OR TWO UNDER THESE WARMER TEMPS DUE TO THE UNCERTAINTY ABOUT THE EXTENT OF THE LOW CLOUD COVER. REGARDLESS...IT WILL BE A VERY WARM DAY AND FORECAST HIGHS WILL BE WITH IN A DEGREE OR TWO OF HIGH TEMPERATURE RECORDS FOR THE 3RD. IN FACT FORECASTS HIGHS ARE WITHIN 5 OR SO DEGREES OF THE ALL TIME RECORD HIGHS FOR THE MONTH OF DECEMBER. SEE THE CLIMATE SECTION BELOW FOR DECEMBER 3RD RECORD HIGHS AND THE RECORD HIGHS FOR THE MONTH OF DECEMBER. THE FRONT AND ATTENDANT S/W WILL BRING ANOTHER CHANCE OF RAIN TO THE AREA MAINLY MONDAY AFTERNOON AND EVENING. AS WITH THE SYSTEM THAT MOVED THROUGH SATURDAY...THE MID LEVELS WILL BE DRY INITIALLY WITH VERY LITTLE SATURATION EXPECTED. WITH THE BEST FORCING EXPECTED TO MOVE THROUGH DURING THE EARLY EVENING HAVE KEPT LOW CHANCE POPS FOR THE AFTERNOON AND 50 POPS EAST OF THE RIVER MONDAY EVENING. SOME THUNDER EAST OF THE RIVER CAN/T BE RULED OUT AT THIS TIME BUT FELT THE POTENTIAL WAS TOO LOW TO INCLUDE IN THE FORECAST FOR NOW. RAINFALL AMOUNTS MONDAY AND MONDAY NIGHT SHOULD BE LIGHT...GENERALLY LESS THAN A TENTH OF AN INCH. QUIET WEATHER SHOULD BE OVER THE AREA TUESDAY AND WEDNESDAY AS HIGH PRESSURE DOMINATES THE REGION. TEMPERATURES WILL COOL OFF SOME FOR MID WEEK BUT WILL STILL BE ABOVE NORMAL. THE NEXT SYSTEM WILL START TO IMPACT THE AREA BY WEDNESDAY NIGHT AS A S/W CROSSES THE NORTHERN ROCKIES AND PUSHES A COLD FRONT INTO THE NORTH CENTRAL STATES AND CENTRAL PLAINS BY THURSDAY MORNING. HAVE GONE WITH SLIGHT CHANCE POPS FOR RAIN NORTHWEST LATE WEDNESDAY NIGHT THEN CHANCE POPS THURSDAY AND THURSDAY NIGHT AS THE SYSTEM MOVES THROUGH. THE ECMWF AND GFS ARE IN GOOD AGREEMENT WITH A BROAD UPPER TROF SETTING UP OVER THE CENTRAL U.S. FOR THE END OF THE WEEK AND PLACING A BAROCLINIC ZONE OVER THE AREA. BECAUSE OF THIS SOME LOW POPS WERE HELD ONTO FOR THE SOUTHERN CWFA INTO FRIDAY NIGHT. TEMPERATURES MAY BE COLD ENOUGH BY FRIDAY NIGHT TO PRODUCE SOME MIXED PRECIPITATION. THE DEVELOPING UPPER TROF SHOULD BRING NEAR NORMAL TEMPERATURES TO THE REGION FOR THE END OF THE WEEK. DLF CLIMATE... RECORD HIGHS FOR DECEMBER 2... MOLINE.........65 IN 1982 CEDAR RAPIDS...66 IN 1962 DUBUQUE........62 IN 1982 BURLINGTON.....66 IN 1962 RECORD WARM LOWS FOR DECEMBER 2... MOLINE.........49 IN 1913 RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGH... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR LEE-VAN BUREN. IL...DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR HANCOCK- MCDONOUGH. MO...DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1144 AM CST SUN DEC 2 2012 .SHORT TERM /TODAY/... FOG HAS BEGUN TO DISSIPATE ACROSS THE FAR NORTHWEST WITH SOME DRY AIR MOVING INTO THE STATE AS A WEAK BOUNDARY SAGS SOUTH. VISIBILITY HAS IMPROVED TO ABOVE ADVISORY LEVEL AND THUS CANCELLED OUT THE NORTHWEST CORNER OF THE FORECAST AREA. THE DRIER AIR LOOKS TO CONTINUE TO ADVECT FURTHER SOUTHEAST AND MASON CITY TO FORT DODGE SHOWING SIGNS OF IMPROVEMENT AS WELL. FORECAST SOUNDINGS DEPICTING VERY WEAK MIXING TODAY...SO FOG WILL TAKE ITS TIME DISSIPATING THIS MORNING. MODELS SHOWING THE WEAK BOUNDARY TO CONTINUE TO MOVE SOUTH THROUGH THE MORNING HOURS BUT WASH OUT BY THIS AFTERNOON WITH WEAK RETURN FLOW. THIS SHOULD BE ENOUGH TO HELP BURN OFF ANY REMAINING FOG ACROSS THE SOUTH THIS MORNING. THE LATEST HRRR HAS FOG PERSISTING THROUGH THE EARLY AFTERNOON HOURS AND SO KEPT MENTION OF PATCHY FOG THROUGH 18Z IN THE SOUTH. WITH THE WARM START TODAY...TEMPS WILL BE WELL ABOVE NORMAL AGAIN TODAY. WENT AT OR SLIGHTLY WARMER THAN THE NAM FOR MAX TEMPS TODAY AND MAY GET EVEN WARMER DEPENDING ON TIMING OF FOG BURNING OFF THIS MORNING. .LONG TERM.../TONIGHT THROUGH SATURDAY/ NON DIURNAL TEMPERATURES ARE EXPECTED TONIGHT. THE DRIER DEWPOINTS DROPPING INTO CENTRAL IOWA EARLY THIS MORNING WILL GIVE WAY TO ANOTHER STRONG SURGE OF LOW LEVEL THETA-E ADVECTION PRIMARILY AFTER MIDNIGHT. LOW TEMPERATURES SHOULD OCCUR BEFORE MIDNIGHT THEN RISING TEMPERATURES AFTER THAT TIME. ADVECTION FOG WILL BE A CONCERN AGAIN AS HIGHER DEWPOINTS IN THE MID 40S TO MID 50S ARRIVE AND OVERRUN THE SFC WITH UPPER LEVEL SOIL TEMPERATURES IN THE MID 30S TO NEAR 40. SOME OF THIS FOG COULD BE DENSE THROUGH MID MONDAY MORNING. TEMPERATURES FOR MONDAY STILL UNCERTAIN AND WILL MIRROR THE SKY CONDITIONS. DESPITE THE VERY WARM 850 MB TEMPERATURES OF +10C AND ABOVE...COLD ADVECTION WILL BE ARRIVING BELOW THIS LEVEL AROUND 900 MB AND WILL ENHANCE THE INVERSION AND LIMIT MIXING DEPTH. SOUTHWEST WINDS WILL INCREASE AHEAD OF THE APPROACHING COOL FRONT (CANT CALL IT COLD BECAUSE TEMPERATURES WILL REMAIN ABOVE NORMAL AFTER PASSAGE). THE INCREASING SOUTHWEST WINDS SHOULD HELP SCATTER THE STRATUS/FOG FROM A PORTION OF THE AREA MAINLY WEST CENTRAL AND SOUTHWEST. TEMPERATURES WILL FALL DURING THE AFTERNOON WITH THE FRONTAL PASSAGE AND A SWITCH TO NORTHWEST WINDS. PRECIPITATION CHANCES WILL BE LIMITED TO PATCHES OF DRIZZLE AND POSSIBLE VERY LIGHT RAIN WITH THE CHANCE OF MEASURABLE PRECIPITATION LOW. MONDAY NIGHT WILL BE MILD (NEARLY 10 DEGREES ABOVE NORMAL) WITH A WARM NOSE AND INVERSION REMAINING AROUND 950 MB. A MUCH DRIER AIRMASS WILL BE IN PLACE ON TUESDAY ALONG WITH WEST TO NORTHWEST DOWNSLOPE FLOW. THIS WILL BE CONDUCIVE TO WARMING AND HIGHS BACK INTO THE LOW TO MID 50S MOST LOCATIONS. A STRONG UPPER WAVE WILL PASS THROUGH THE NORTHERN GREAT LAKES AND ONTARIO REGION TUESDAY AND TUESDAY NIGHT. THIS SYSTEM WILL SWING A COLD FRONT THROUGH IOWA TUESDAY NIGHT. THE NAM IS MUCH MORE AGGRESSIVE ON THE AMOUNT SHALLOW NEAR SFC COLD AIR WILL ARRIVE WITH THE SYSTEM. THE NAM TENDS TO CATCH THESE LOW LEVEL COLD INTRUSIONS AND HAVE LEANED CLOSER TO THIS SOLUTION. HIGH PRESSURE WILL FOLLOW TUESDAY NIGHT THEN SHIFT OFF TO THE EAST ON WEDNESDAY LEADING TO A QUICK RETURN TO SOUTHERLY FLOW. INCREASING THETA-E ADVECTION WEDNESDAY WILL BRING INCREASING MID LEVEL CLOUDS. THE CLOUDS COULD PUT A DAMPER ON TEMPERATURES WEDNESDAY IF THEY ARRIVE EARLY ENOUGH...FOR NOW HAVE TRENDED TEMPERATURES TOWARD A LATER ARRIVAL. THE REMAINDER OF THE EXTENDED IS DEPENDENT ON THE GRADUAL EROSION OF THE ZONAL FLOW AND THE EVOLUTION OF A DEVELOPING LONG WAVE TROUGH AND THE ASSOCIATED IMPENDING ARRIVAL OF COLDER WEATHER. THE TRENDS POINT TO A RETURN TO MORE NORMAL TEMPERATURES SHOULD BEGIN BY FRIDAY. HINTS AT WINTER WEATHER ON THE HORIZON WITH THE GFS AND ECMWF EACH CONTINUING TO SUGGEST SNOW POTENTIAL SOMETIME IN THE DAY 7-10 RANGE. && .AVIATION...02/18Z COLD FRONT BECOMING NEARLY STATIONARY NEAR A KDBQ-JUST SOUTH OF KDSM TO SOUTH OF KOMA LINE WILL BEGIN TO LIFT NORTH AS A WARM FRONT TONIGHT. SLOW IMPROVEMENT IS EXPECTED ACROSS THE SOUTHERN HALF OF IOWA THIS AFTERNOON...BUT THE SOUTHERN TAFS MAY HAVE TROUBLE IMPROVING BEYOND MVFR. WIDESPREAD IFR/LIFR CIGS EXPECTED TONIGHT. EXPERIMENTAL WRF SIMULATIONS CAPTURE THE TREND WELL AND HAVE TIMING CLOSE TO WHAT IS IN THE TAFS FRO THE REFORMATION OF THE STRATUS. WITH BOUNDARY LAYER TEMPS AROUND 20 KTS AND H8 WINDS 35 TO 40 KTS...DO NOT EXPECT AS MUCH DENSE FOG...BUT STRATUS WILL BE VERY EXTENSIVE WITH CONDITIONS NOT IMPROVING BEFORE LATE MON MORNING. && .DMX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ADAIR-ADAMS-APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER- BUTLER-CALHOUN-CARROLL-CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS- DAVIS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON- HANCOCK-HARDIN-HUMBOLDT-JASPER-LUCAS-MADISON-MAHASKA-MARION- MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA- TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...MS DEC 12 LONG TERM...DONAVON AVIATION...MS DEC 12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1016 AM CST SUN DEC 2 2012 .UPDATE... BASED ON OBSERVATIONS... SPOTTER REPORTS AND WEBCAMS... HAVE EXTENDED THE DENSE FOG ADVISORY UNTIL 18Z. ALSO ADDED A FEW COUNTIES OVER PORTIONS OF SOUTHEAST IA AND WEST CENTRAL IL. BESIDES FOG... SLOWED THE CLEARING TREND FOR PORTIONS OF SOUTHEAST IA... NORTHEAST MO AND WEST CENTRAL IL UNTIL MID TO LATE AFTN AND POTENTIAL FOR SOME AREAS TO REMAIN CLOUDY ALL DAY SOUTH WITH LIGHT WINDS/WEAK MIXING AND ABUNDANT MOISTURE. && .PREV DISCUSSION... /ISSUED 559 AM CST SUN DEC 2 2012/ UPDATE... THE LONE WEB CAM NEAR THE IA/MO BORDER INDICATES THICK FOG IN THE AREA. KMPZ VISIBILITY IS DOWN AS IS KIRK. THUS DENSE FOG IS OCCURRING IN VAN BUREN AND HENRY COUNTIES IN IOWA...AND PROBABLY IN SCOTLAND/CLARK COUNTIES IN MISSOURI AND THE WESTERN PART OF LEE COUNTY IN IOWA. THUS THE DENSE FOG ADVISORY WILL BE EXPANDED INTO THESE AREAS AND WILL ALSO BE EXTENDED 1 HOUR EVERYWHERE. A WEAK TROF IS MOVING THROUGH THE CENTRAL CWFA WHICH MAY BE PARTIALLY RESPONSIBLE FOR THE INCREASE IN DENSE FOG DOWN SOUTH. SATELLITE TRENDS CONTINUE TO SHOW STRONG SUBSIDENCE IN CENTRAL AND WESTERN IOWA WHICH IS JUST BEGINNING TO ENTER THE FAR NORTHWEST PART OF THE CWFA. FOR THE MOST PART...THE GENERAL TREND OF THE FCST LOOKS TO BE ON TRACK WITH CLEARING OCCURRING DURING THE DAY. ..08.. AVIATION... CONDITIONS RANGE FROM VLIFR TO MVFR WITH LOW CLOUDS/FOG. CONDITIONS WILL SLOWLY IMPROVE TO VFR WITH MOST OF THE IMPROVEMENT OCCURRING AFT 15Z/02. AS HIGH PRESSURE MOVES THROUGH THE AREA WINDS WILL REMAIN LIGHT/VARIABLE. BASED ON WHAT IS BEING SUGGESTED BY MODEL TRENDS...MINIMALLY MVFR CONDITIONS WILL MOVE BACK INTO EASTERN IOWA AND NORTHERN ILLINOIS AFT 04Z/03. ..08.. PREV DISCUSSION... /ISSUED 300 AM CST SUN DEC 2 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM ROUGHLY GREEN BAY BACK TO THE NEBRASKA/KANSAS BORDER. ANOTHER FRONT RAN FROM A LOW NEAR KSAW BACK TO AROUND KYKN. DEW POINTS OVER THE GREAT LAKES AND MIDWEST WERE IN THE 40S AND 50S WITH 30S IN THE PLAINS. SHORT TERM...TODAY AND TONIGHT THE IMMEDIATE CONCERN IS FOG POTENTIAL AND THE CURRENT HEADLINES. SATELLITE TRENDS SHOW GOOD SUBSIDENCE OVER NORTHWEST/WESTERN IOWA WHICH HAS ALLOWED A LARGE EXPANSE OF DENSE FOG TO FORM IN THE MOIST AIR. SAID FOG HAS EXPANDED EASTWARD IN THE LIGHT WINDS/CONVERGENCE TO INCLUDE ROUGHLY THE NORTHWEST THIRD OF THE CWFA. BASED ON CURRENT TRENDS WITH INPUT FROM THE RAP MODEL...THE CURRENT FOG HEADLINES LOOK OK. HOWEVER...GIVEN THE EXTREMELY WARM AND MOIST AIR OVER THE CWFA THERE IS REASONABLE POTENTIAL FOR PATCHY IF NOT LOCALIZED AREAS OF FOG DEVELOPING AHEAD OF THE CURRENT FOG HEADLINES ESPECIALLY IF CLEAR POCKETS DEVELOP IN THE LOW CLOUDS. THE OVERALL SUBSIDENCE INCREASES DURING THE DAY SO CLEARING IS EXPECTED FROM WEST TO EAST DURING THE DAY. GIVEN THE EXCEPTIONALLY MILD START...MAX TEMPERATURES WILL BE WELL ABOVE NORMAL FOR EARLY DECEMBER. RECORD HIGHS APPEAR DOUBTFUL BUT KBRL MAY BE CLOSE BASED ON PROJECTED MAX TEMPERATURES. A RECORD WARM LOW WILL NOT BE REALIZED AT KDBQ BUT COULD OCCUR AT KMLI. QUIET CONDITIONS WILL BE SEEN DURING THE EVENING ACROSS THE AREA. THE WARM TEMPERATURES COMBINED WITH LIGHT WINDS AND INITIALLY CLEAR OR NEARLY CLEAR SKIES SHOULD ALLOW PATCHY FOG TO DEVELOP BY LATE EVENING ACROSS THE NORTHEAST QUADRANT OF THE CWFA. AFTER MIDNIGHT...ANOTHER INFLUX OF MOISTURE WILL MOVE BACK INTO THE AREA WHICH SHOULD INCLUDE CONSIDERABLE LOW CLOUDS. PATCHY FOG SHOULD DEVELOP OVER MOST OF THE AREA. THE NORTHEAST QUADRANT OF THE CWFA WILL HAVE LIGHT WINDS AND CLEAR SKIES THE LONGEST SO THE FOG SHOULD BECOME MORE WIDESPREAD THERE. MIN TEMPERATURES TONIGHT WILL BE ABOVE THE NORMAL MAX TEMPERATURES. ..08.. LONG TERM...MONDAY THROUGH SATURDAY MODELS CONTINUE TO SHOW ZONAL FLOW OVER U.S. THROUGH MID WEEK WITH SOME AMPLIFICATION IN THE FLOW DEVELOPING LATE WEEK AS A BROAD H5 TROF FORMS OVER THE WESTERN AND CENTRAL U.S. IN THE NEAR TERM...RECORD OR NEAR RECORD WARMTH LOOKS ON TRACK FOR MONDAY WITH THE MODELS IN GOOD AGREEMENT MOVING UNSEASONABLY WARM AIR NORTH OUT OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AHEAD OF A COLD FRONT THAT SHOULD BE MOVING INTO THE CENTRAL IA BY MID DAY. H8 TEMPS IN THE 10C TO 15C RANGE ARE PROGGED TO BE OVER THE AREA MONDAY MORNING. A SURFACE WARM FRONT SHOULD BE NEAR THE IA/MO BORDER EARLY MONDAY AND WILL MOVE NORTH DURING THE DAY WITH SOUTH WINDS INCREASING INTO THE 15 TO 25 MPH IN THE WARM SECTOR. ADDING SOME UNCERTAINTY TO THE WARM UP WILL BE UNUSUALLY HIGH LOW LEVEL MOISTURE THAT WILL BE OVER AREA BY MONDAY MORNING. THE MOIST LOW LEVELS SHOULD RESULT IN STRATUS AS WELL AS SOME PATCHY DRIZZLE AND FOG DURING THE MORNING WHICH IS EXPECTED TO MIX OUT SOME DURING THE DAY WITH INCREASING SOUTH WINDS. SOME MOS GUIDANCE INCLUDING THE MET AND ECMWF MOS IS SUGGESTING TEMPERATURES IN THE LOW 70S SOUTH TO MID 60S NORTH FOR HIGHS. HOWEVER HAVE KEPT A DEGREE OR TWO UNDER THESE WARMER TEMPS DUE TO THE UNCERTAINTY ABOUT THE EXTENT OF THE LOW CLOUD COVER. REGARDLESS...IT WILL BE A VERY WARM DAY AND FORECAST HIGHS WILL BE WITH IN A DEGREE OR TWO OF HIGH TEMPERATURE RECORDS FOR THE 3RD. IN FACT FORECASTS HIGHS ARE WITHIN 5 OR SO DEGREES OF THE ALL TIME RECORD HIGHS FOR THE MONTH OF DECEMBER. SEE THE CLIMATE SECTION BELOW FOR DECEMBER 3RD RECORD HIGHS AND THE RECORD HIGHS FOR THE MONTH OF DECEMBER. THE FRONT AND ATTENDANT S/W WILL BRING ANOTHER CHANCE OF RAIN TO THE AREA MAINLY MONDAY AFTERNOON AND EVENING. AS WITH THE SYSTEM THAT MOVED THROUGH SATURDAY...THE MID LEVELS WILL BE DRY INITIALLY WITH VERY LITTLE SATURATION EXPECTED. WITH THE BEST FORCING EXPECTED TO MOVE THROUGH DURING THE EARLY EVENING HAVE KEPT LOW CHANCE POPS FOR THE AFTERNOON AND 50 POPS EAST OF THE RIVER MONDAY EVENING. SOME THUNDER EAST OF THE RIVER CAN/T BE RULED OUT AT THIS TIME BUT FELT THE POTENTIAL WAS TOO LOW TO INCLUDE IN THE FORECAST FOR NOW. RAINFALL AMOUNTS MONDAY AND MONDAY NIGHT SHOULD BE LIGHT...GENERALLY LESS THAN A TENTH OF AN INCH. QUIET WEATHER SHOULD BE OVER THE AREA TUESDAY AND WEDNESDAY AS HIGH PRESSURE DOMINATES THE REGION. TEMPERATURES WILL COOL OFF SOME FOR MID WEEK BUT WILL STILL BE ABOVE NORMAL. THE NEXT SYSTEM WILL START TO IMPACT THE AREA BY WEDNESDAY NIGHT AS A S/W CROSSES THE NORTHERN ROCKIES AND PUSHES A COLD FRONT INTO THE NORTH CENTRAL STATES AND CENTRAL PLAINS BY THURSDAY MORNING. HAVE GONE WITH SLIGHT CHANCE POPS FOR RAIN NORTHWEST LATE WEDNESDAY NIGHT THEN CHANCE POPS THURSDAY AND THURSDAY NIGHT AS THE SYSTEM MOVES THROUGH. THE ECMWF AND GFS ARE IN GOOD AGREEMENT WITH A BROAD UPPER TROF SETTING UP OVER THE CENTRAL U.S. FOR THE END OF THE WEEK AND PLACING A BAROCLINIC ZONE OVER THE AREA. BECAUSE OF THIS SOME LOW POPS WERE HELD ONTO FOR THE SOUTHERN CWFA INTO FRIDAY NIGHT. TEMPERATURES MAY BE COLD ENOUGH BY FRIDAY NIGHT TO PRODUCE SOME MIXED PRECIPITATION. THE DEVELOPING UPPER TROF SHOULD BRING NEAR NORMAL TEMPERATURES TO THE REGION FOR THE END OF THE WEEK. DLF CLIMATE... RECORD HIGHS FOR DECEMBER 2... MOLINE.........65 IN 1982 CEDAR RAPIDS...66 IN 1962 DUBUQUE........62 IN 1982 BURLINGTON.....66 IN 1962 RECORD WARM LOWS FOR DECEMBER 2... MOLINE.........49 IN 1913 RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGH... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR BENTON-BUCHANAN- DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-JEFFERSON-JOHNSON- JONES-KEOKUK-LEE-LINN-VAN BUREN-WASHINGTON. IL...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR HANCOCK-HENDERSON- MCDONOUGH-WARREN. MO...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR CLARK-SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
559 AM CST SUN DEC 2 2012 .UPDATE... THE LONE WEB CAM NEAR THE IA/MO BORDER INDICATES THICK FOG IN THE AREA. KMPZ VISIBILITY IS DOWN AS IS KIRK. THUS DENSE FOG IS OCCURRING IN VAN BUREN AND HENRY COUNTIES IN IOWA...AND PROBABLY IN SCOTLAND/CLARK COUNTIES IN MISSOURI AND THE WESTERN PART OF LEE COUNTY IN IOWA. THUS THE DENSE FOG ADVISORY WILL BE EXPANDED INTO THESE AREAS AND WILL ALSO BE EXTENDED 1 HOUR EVERYWHERE. A WEAK TROF IS MOVING THROUGH THE CENTRAL CWFA WHICH MAY BE PARTIALLY RESPONSIBLE FOR THE INCREASE IN DENSE FOG DOWN SOUTH. SATELLITE TRENDS CONTINUE TO SHOW STRONG SUBSIDENCE IN CENTRAL AND WESTERN IOWA WHICH IS JUST BEGINNING TO ENTER THE FAR NORTHWEST PART OF THE CWFA. FOR THE MOST PART...THE GENERAL TREND OF THE FCST LOOKS TO BE ON TRACK WITH CLEARING OCCURRING DURING THE DAY. ..08.. && .AVIATION... CONDITIONS RANGE FROM VLIFR TO MVFR WITH LOW CLOUDS/FOG. CONDITIONS WILL SLOWLY IMPROVE TO VFR WITH MOST OF THE IMPROVEMENT OCCURRING AFT 15Z/02. AS HIGH PRESSURE MOVES THROUGH THE AREA WINDS WILL REMAIN LIGHT/VARIABLE. BASED ON WHAT IS BEING SUGGESTED BY MODEL TRENDS...MINIMALLY MVFR CONDITIONS WILL MOVE BACK INTO EASTERN IOWA AND NORTHERN ILLINOIS AFT 04Z/03. ..08.. && .PREV DISCUSSION... /ISSUED 300 AM CST SUN DEC 2 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM ROUGHLY GREEN BAY BACK TO THE NEBRASKA/KANSAS BORDER. ANOTHER FRONT RAN FROM A LOW NEAR KSAW BACK TO AROUND KYKN. DEW POINTS OVER THE GREAT LAKES AND MIDWEST WERE IN THE 40S AND 50S WITH 30S IN THE PLAINS. SHORT TERM...TODAY AND TONIGHT THE IMMEDIATE CONCERN IS FOG POTENTIAL AND THE CURRENT HEADLINES. SATELLITE TRENDS SHOW GOOD SUBSIDENCE OVER NORTHWEST/WESTERN IOWA WHICH HAS ALLOWED A LARGE EXPANSE OF DENSE FOG TO FORM IN THE MOIST AIR. SAID FOG HAS EXPANDED EASTWARD IN THE LIGHT WINDS/CONVERGENCE TO INCLUDE ROUGHLY THE NORTHWEST THIRD OF THE CWFA. BASED ON CURRENT TRENDS WITH INPUT FROM THE RAP MODEL...THE CURRENT FOG HEADLINES LOOK OK. HOWEVER...GIVEN THE EXTREMELY WARM AND MOIST AIR OVER THE CWFA THERE IS REASONABLE POTENTIAL FOR PATCHY IF NOT LOCALIZED AREAS OF FOG DEVELOPING AHEAD OF THE CURRENT FOG HEADLINES ESPECIALLY IF CLEAR POCKETS DEVELOP IN THE LOW CLOUDS. THE OVERALL SUBSIDENCE INCREASES DURING THE DAY SO CLEARING IS EXPECTED FROM WEST TO EAST DURING THE DAY. GIVEN THE EXCEPTIONALLY MILD START...MAX TEMPERATURES WILL BE WELL ABOVE NORMAL FOR EARLY DECEMBER. RECORD HIGHS APPEAR DOUBTFUL BUT KBRL MAY BE CLOSE BASED ON PROJECTED MAX TEMPERATURES. A RECORD WARM LOW WILL NOT BE REALIZED AT KDBQ BUT COULD OCCUR AT KMLI. QUIET CONDITIONS WILL BE SEEN DURING THE EVENING ACROSS THE AREA. THE WARM TEMPERATURES COMBINED WITH LIGHT WINDS AND INITIALLY CLEAR OR NEARLY CLEAR SKIES SHOULD ALLOW PATCHY FOG TO DEVELOP BY LATE EVENING ACROSS THE NORTHEAST QUADRANT OF THE CWFA. AFTER MIDNIGHT...ANOTHER INFLUX OF MOISTURE WILL MOVE BACK INTO THE AREA WHICH SHOULD INCLUDE CONSIDERABLE LOW CLOUDS. PATCHY FOG SHOULD DEVELOP OVER MOST OF THE AREA. THE NORTHEAST QUADRANT OF THE CWFA WILL HAVE LIGHT WINDS AND CLEAR SKIES THE LONGEST SO THE FOG SHOULD BECOME MORE WIDESPREAD THERE. MIN TEMPERATURES TONIGHT WILL BE ABOVE THE NORMAL MAX TEMPERATURES. ..08.. LONG TERM...MONDAY THROUGH SATURDAY MODELS CONTINUE TO SHOW ZONAL FLOW OVER U.S. THROUGH MID WEEK WITH SOME AMPLIFICATION IN THE FLOW DEVELOPING LATE WEEK AS A BROAD H5 TROF FORMS OVER THE WESTERN AND CENTRAL U.S. IN THE NEAR TERM...RECORD OR NEAR RECORD WARMTH LOOKS ON TRACK FOR MONDAY WITH THE MODELS IN GOOD AGREEMENT MOVING UNSEASONABLY WARM AIR NORTH OUT OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AHEAD OF A COLD FRONT THAT SHOULD BE MOVING INTO THE CENTRAL IA BY MID DAY. H8 TEMPS IN THE 10C TO 15C RANGE ARE PROGGED TO BE OVER THE AREA MONDAY MORNING. A SURFACE WARM FRONT SHOULD BE NEAR THE IA/MO BORDER EARLY MONDAY AND WILL MOVE NORTH DURING THE DAY WITH SOUTH WINDS INCREASING INTO THE 15 TO 25 MPH IN THE WARM SECTOR. ADDING SOME UNCERTAINTY TO THE WARM UP WILL BE UNUSUALLY HIGH LOW LEVEL MOISTURE THAT WILL BE OVER AREA BY MONDAY MORNING. THE MOIST LOW LEVELS SHOULD RESULT IN STRATUS AS WELL AS SOME PATCHY DRIZZLE AND FOG DURING THE MORNING WHICH IS EXPECTED TO MIX OUT SOME DURING THE DAY WITH INCREASING SOUTH WINDS. SOME MOS GUIDANCE INCLUDING THE MET AND ECMWF MOS IS SUGGESTING TEMPERATURES IN THE LOW 70S SOUTH TO MID 60S NORTH FOR HIGHS. HOWEVER HAVE KEPT A DEGREE OR TWO UNDER THESE WARMER TEMPS DUE TO THE UNCERTAINTY ABOUT THE EXTENT OF THE LOW CLOUD COVER. REGARDLESS...IT WILL BE A VERY WARM DAY AND FORECAST HIGHS WILL BE WITH IN A DEGREE OR TWO OF HIGH TEMPERATURE RECORDS FOR THE 3RD. IN FACT FORECASTS HIGHS ARE WITHIN 5 OR SO DEGREES OF THE ALL TIME RECORD HIGHS FOR THE MONTH OF DECEMBER. SEE THE CLIMATE SECTION BELOW FOR DECEMBER 3RD RECORD HIGHS AND THE RECORD HIGHS FOR THE MONTH OF DECEMBER. THE FRONT AND ATTENDANT S/W WILL BRING ANOTHER CHANCE OF RAIN TO THE AREA MAINLY MONDAY AFTERNOON AND EVENING. AS WITH THE SYSTEM THAT MOVED THROUGH SATURDAY...THE MID LEVELS WILL BE DRY INITIALLY WITH VERY LITTLE SATURATION EXPECTED. WITH THE BEST FORCING EXPECTED TO MOVE THROUGH DURING THE EARLY EVENING HAVE KEPT LOW CHANCE POPS FOR THE AFTERNOON AND 50 POPS EAST OF THE RIVER MONDAY EVENING. SOME THUNDER EAST OF THE RIVER CAN/T BE RULED OUT AT THIS TIME BUT FELT THE POTENTIAL WAS TOO LOW TO INCLUDE IN THE FORECAST FOR NOW. RAINFALL AMOUNTS MONDAY AND MONDAY NIGHT SHOULD BE LIGHT...GENERALLY LESS THAN A TENTH OF AN INCH. QUIET WEATHER SHOULD BE OVER THE AREA TUESDAY AND WEDNESDAY AS HIGH PRESSURE DOMINATES THE REGION. TEMPERATURES WILL COOL OFF SOME FOR MID WEEK BUT WILL STILL BE ABOVE NORMAL. THE NEXT SYSTEM WILL START TO IMPACT THE AREA BY WEDNESDAY NIGHT AS A S/W CROSSES THE NORTHERN ROCKIES AND PUSHES A COLD FRONT INTO THE NORTH CENTRAL STATES AND CENTRAL PLAINS BY THURSDAY MORNING. HAVE GONE WITH SLIGHT CHANCE POPS FOR RAIN NORTHWEST LATE WEDNESDAY NIGHT THEN CHANCE POPS THURSDAY AND THURSDAY NIGHT AS THE SYSTEM MOVES THROUGH. THE ECMWF AND GFS ARE IN GOOD AGREEMENT WITH A BROAD UPPER TROF SETTING UP OVER THE CENTRAL U.S. FOR THE END OF THE WEEK AND PLACING A BAROCLINIC ZONE OVER THE AREA. BECAUSE OF THIS SOME LOW POPS WERE HELD ONTO FOR THE SOUTHERN CWFA INTO FRIDAY NIGHT. TEMPERATURES MAY BE COLD ENOUGH BY FRIDAY NIGHT TO PRODUCE SOME MIXED PRECIPITATION. THE DEVELOPING UPPER TROF SHOULD BRING NEAR NORMAL TEMPERATURES TO THE REGION FOR THE END OF THE WEEK. DLF CLIMATE... RECORD HIGHS FOR DECEMBER 2... MOLINE.........65 IN 1982 CEDAR RAPIDS...66 IN 1962 DUBUQUE........62 IN 1982 BURLINGTON.....66 IN 1962 RECORD WARM LOWS FOR DECEMBER 2... MOLINE.........49 IN 1913 RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGH... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BENTON- BUCHANAN-DELAWARE-DUBUQUE-HENRY IA-IOWA-JEFFERSON-JOHNSON- JONES-KEOKUK-LEE-LINN-VAN BUREN-WASHINGTON. IL...NONE. MO...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
540 AM CST SUN DEC 2 2012 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TODAY/... FOG HAS BEGUN TO DISSIPATE ACROSS THE FAR NORTHWEST WITH SOME DRY AIR MOVING INTO THE STATE AS A WEAK BOUNDARY SAGS SOUTH. VISIBILITY HAS IMPROVED TO ABOVE ADVISORY LEVEL AND THUS CANCELLED OUT THE NORTHWEST CORNER OF THE FORECAST AREA. THE DRIER AIR LOOKS TO CONTINUE TO ADVECT FURTHER SOUTHEAST AND MASON CITY TO FORT DODGE SHOWING SIGNS OF IMPROVEMENT AS WELL. FORECAST SOUNDINGS DEPICTING VERY WEAK MIXING TODAY...SO FOG WILL TAKE ITS TIME DISSIPATING THIS MORNING. MODELS SHOWING THE WEAK BOUNDARY TO CONTINUE TO MOVE SOUTH THROUGH THE MORNING HOURS BUT WASH OUT BY THIS AFTERNOON WITH WEAK RETURN FLOW. THIS SHOULD BE ENOUGH TO HELP BURN OFF ANY REMAINING FOG ACROSS THE SOUTH THIS MORNING. THE LATEST HRRR HAS FOG PERSISTING THROUGH THE EARLY AFTERNOON HOURS AND SO KEPT MENTION OF PATCHY FOG THROUGH 18Z IN THE SOUTH. WITH THE WARM START TODAY...TEMPS WILL BE WELL ABOVE NORMAL AGAIN TODAY. WENT AT OR SLIGHTLY WARMER THAN THE NAM FOR MAX TEMPS TODAY AND MAY GET EVEN WARMER DEPENDING ON TIMING OF FOG BURNING OFF THIS MORNING. .LONG TERM.../TONIGHT THROUGH SATURDAY/ NON DIURNAL TEMPERATURES ARE EXPECTED TONIGHT. THE DRIER DEWPOINTS DROPPING INTO CENTRAL IOWA EARLY THIS MORNING WILL GIVE WAY TO ANOTHER STRONG SURGE OF LOW LEVEL THETA-E ADVECTION PRIMARILY AFTER MIDNIGHT. LOW TEMPERATURES SHOULD OCCUR BEFORE MIDNIGHT THEN RISING TEMPERATURES AFTER THAT TIME. ADVECTION FOG WILL BE A CONCERN AGAIN AS HIGHER DEWPOINTS IN THE MID 40S TO MID 50S ARRIVE AND OVERRUN THE SFC WITH UPPER LEVEL SOIL TEMPERATURES IN THE MID 30S TO NEAR 40. SOME OF THIS FOG COULD BE DENSE THROUGH MID MONDAY MORNING. TEMPERATURES FOR MONDAY STILL UNCERTAIN AND WILL MIRROR THE SKY CONDITIONS. DESPITE THE VERY WARM 850 MB TEMPERATURES OF +10C AND ABOVE...COLD ADVECTION WILL BE ARRIVING BELOW THIS LEVEL AROUND 900 MB AND WILL ENHANCE THE INVERSION AND LIMIT MIXING DEPTH. SOUTHWEST WINDS WILL INCREASE AHEAD OF THE APPROACHING COOL FRONT (CANT CALL IT COLD BECAUSE TEMPERATURES WILL REMAIN ABOVE NORMAL AFTER PASSAGE). THE INCREASING SOUTHWEST WINDS SHOULD HELP SCATTER THE STRATUS/FOG FROM A PORTION OF THE AREA MAINLY WEST CENTRAL AND SOUTHWEST. TEMPERATURES WILL FALL DURING THE AFTERNOON WITH THE FRONTAL PASSAGE AND A SWITCH TO NORTHWEST WINDS. PRECIPITATION CHANCES WILL BE LIMITED TO PATCHES OF DRIZZLE AND POSSIBLE VERY LIGHT RAIN WITH THE CHANCE OF MEASURABLE PRECIPITATION LOW. MONDAY NIGHT WILL BE MILD (NEARLY 10 DEGREES ABOVE NORMAL) WITH A WARM NOSE AND INVERSION REMAINING AROUND 950 MB. A MUCH DRIER AIRMASS WILL BE IN PLACE ON TUESDAY ALONG WITH WEST TO NORTHWEST DOWNSLOPE FLOW. THIS WILL BE CONDUCIVE TO WARMING AND HIGHS BACK INTO THE LOW TO MID 50S MOST LOCATIONS. A STRONG UPPER WAVE WILL PASS THROUGH THE NORTHERN GREAT LAKES AND ONTARIO REGION TUESDAY AND TUESDAY NIGHT. THIS SYSTEM WILL SWING A COLD FRONT THROUGH IOWA TUESDAY NIGHT. THE NAM IS MUCH MORE AGGRESSIVE ON THE AMOUNT SHALLOW NEAR SFC COLD AIR WILL ARRIVE WITH THE SYSTEM. THE NAM TENDS TO CATCH THESE LOW LEVEL COLD INTRUSIONS AND HAVE LEANED CLOSER TO THIS SOLUTION. HIGH PRESSURE WILL FOLLOW TUESDAY NIGHT THEN SHIFT OFF TO THE EAST ON WEDNESDAY LEADING TO A QUICK RETURN TO SOUTHERLY FLOW. INCREASING THETA-E ADVECTION WEDNESDAY WILL BRING INCREASING MID LEVEL CLOUDS. THE CLOUDS COULD PUT A DAMPER ON TEMPERATURES WEDNESDAY IF THEY ARRIVE EARLY ENOUGH...FOR NOW HAVE TRENDED TEMPERATURES TOWARD A LATER ARRIVAL. THE REMAINDER OF THE EXTENDED IS DEPENDENT ON THE GRADUAL EROSION OF THE ZONAL FLOW AND THE EVOLUTION OF A DEVELOPING LONG WAVE TROUGH AND THE ASSOCIATED IMPENDING ARRIVAL OF COLDER WEATHER. THE TRENDS POINT TO A RETURN TO MORE NORMAL TEMPERATURES SHOULD BEGIN BY FRIDAY. HINTS AT WINTER WEATHER ON THE HORIZON WITH THE GFS AND ECMWF EACH CONTINUING TO SUGGEST SNOW POTENTIAL SOMETIME IN THE DAY 7-10 RANGE. && .AVIATION...02/12Z LIFR/IFR VIS/CIGS DUE TO THE THICK FOG WILL CONTINUE TO PLAGUE DSM/ALO/OTM OVER THE NEXT COUPLE OF HOURS...THEN LIFTING TO MVFR BY 15Z. HAVE VFR CONDITIONS AT ALL TAF SITES BY 18Z...BUT CHANCE THERE MAY BE SOME LINGERING MVFR VIS AT DSM/OTM. SOME DRIER AIR HAS CAUSED THE FOG TO LIFT AT FOD/MCW BUT MAY STILL RECEIVE IFR VIS THROUGH 13Z AT FOD. ANOTHER ROUND OF FOG IS LIKELY TO DEVELOP PAST 06Z MONDAY WITH THE BOUNDARY LAYER MOISTURE REMAINING AND FAIRLY STRONG INVERSION DEVELOPING. HAVE MVFR VIS MENTIONED TOWARDS THE END OF THE FORECAST. && .DMX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ADAIR-ADAMS-APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER- BUTLER-CALHOUN-CARROLL-CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS- DAVIS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON- HANCOCK-HARDIN-HUMBOLDT-JASPER-LUCAS-MADISON-MAHASKA-MARION- MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA- TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
350 AM CST SUN DEC 2 2012 .SHORT TERM /TODAY/... FOG HAS BEGUN TO DISSIPATE ACROSS THE FAR NORTHWEST WITH SOME DRY AIR MOVING INTO THE STATE AS A WEAK BOUNDARY SAGS SOUTH. VISIBILITY HAS IMPROVED TO ABOVE ADVISORY LEVEL AND THUS CANCELLED OUT THE NORTHWEST CORNER OF THE FORECAST AREA. THE DRIER AIR LOOKS TO CONTINUE TO ADVECT FURTHER SOUTHEAST AND MASON CITY TO FORT DODGE SHOWING SIGNS OF IMPROVEMENT AS WELL. FORECAST SOUNDINGS DEPICTING VERY WEAK MIXING TODAY...SO FOG WILL TAKE ITS TIME DISSIPATING THIS MORNING. MODELS SHOWING THE WEAK BOUNDARY TO CONTINUE TO MOVE SOUTH THROUGH THE MORNING HOURS BUT WASH OUT BY THIS AFTERNOON WITH WEAK RETURN FLOW. THIS SHOULD BE ENOUGH TO HELP BURN OFF ANY REMAINING FOG ACROSS THE SOUTH THIS MORNING. THE LATEST HRRR HAS FOG PERSISTING THROUGH THE EARLY AFTERNOON HOURS AND SO KEPT MENTION OF PATCHY FOG THROUGH 18Z IN THE SOUTH. WITH THE WARM START TODAY...TEMPS WILL BE WELL ABOVE NORMAL AGAIN TODAY. WENT AT OR SLIGHTLY WARMER THAN THE NAM FOR MAX TEMPS TODAY AND MAY GET EVEN WARMER DEPENDING ON TIMING OF FOG BURNING OFF THIS MORNING. .LONG TERM.../TONIGHT THROUGH SATURDAY/ NON DIURNAL TEMPERATURES ARE EXPECTED TONIGHT. THE DRIER DEWPOINTS DROPPING INTO CENTRAL IOWA EARLY THIS MORNING WILL GIVE WAY TO ANOTHER STRONG SURGE OF LOW LEVEL THETA-E ADVECTION PRIMARILY AFTER MIDNIGHT. LOW TEMPERATURES SHOULD OCCUR BEFORE MIDNIGHT THEN RISING TEMPERATURES AFTER THAT TIME. ADVECTION FOG WILL BE A CONCERN AGAIN AS HIGHER DEWPOINTS IN THE MID 40S TO MID 50S ARRIVE AND OVERRUN THE SFC WITH UPPER LEVEL SOIL TEMPERATURES IN THE MID 30S TO NEAR 40. SOME OF THIS FOG COULD BE DENSE THROUGH MID MONDAY MORNING. TEMPERATURES FOR MONDAY STILL UNCERTAIN AND WILL MIRROR THE SKY CONDITIONS. DESPITE THE VERY WARM 850 MB TEMPERATURES OF +10C AND ABOVE...COLD ADVECTION WILL BE ARRIVING BELOW THIS LEVEL AROUND 900 MB AND WILL ENHANCE THE INVERSION AND LIMIT MIXING DEPTH. SOUTHWEST WINDS WILL INCREASE AHEAD OF THE APPROACHING COOL FRONT (CANT CALL IT COLD BECAUSE TEMPERATURES WILL REMAIN ABOVE NORMAL AFTER PASSAGE). THE INCREASING SOUTHWEST WINDS SHOULD HELP SCATTER THE STRATUS/FOG FROM A PORTION OF THE AREA MAINLY WEST CENTRAL AND SOUTHWEST. TEMPERATURES WILL FALL DURING THE AFTERNOON WITH THE FRONTAL PASSAGE AND A SWITCH TO NORTHWEST WINDS. PRECIPITATION CHANCES WILL BE LIMITED TO PATCHES OF DRIZZLE AND POSSIBLE VERY LIGHT RAIN WITH THE CHANCE OF MEASURABLE PRECIPITATION LOW. MONDAY NIGHT WILL BE MILD (NEARLY 10 DEGREES ABOVE NORMAL) WITH A WARM NOSE AND INVERSION REMAINING AROUND 950 MB. A MUCH DRIER AIRMASS WILL BE IN PLACE ON TUESDAY ALONG WITH WEST TO NORTHWEST DOWNSLOPE FLOW. THIS WILL BE CONDUCIVE TO WARMING AND HIGHS BACK INTO THE LOW TO MID 50S MOST LOCATIONS. A STRONG UPPER WAVE WILL PASS THROUGH THE NORTHERN GREAT LAKES AND ONTARIO REGION TUESDAY AND TUESDAY NIGHT. THIS SYSTEM WILL SWING A COLD FRONT THROUGH IOWA TUESDAY NIGHT. THE NAM IS MUCH MORE AGGRESSIVE ON THE AMOUNT SHALLOW NEAR SFC COLD AIR WILL ARRIVE WITH THE SYSTEM. THE NAM TENDS TO CATCH THESE LOW LEVEL COLD INTRUSIONS AND HAVE LEANED CLOSER TO THIS SOLUTION. HIGH PRESSURE WILL FOLLOW TUESDAY NIGHT THEN SHIFT OFF TO THE EAST ON WEDNESDAY LEADING TO A QUICK RETURN TO SOUTHERLY FLOW. INCREASING THETA-E ADVECTION WEDNESDAY WILL BRING INCREASING MID LEVEL CLOUDS. THE CLOUDS COULD PUT A DAMPER ON TEMPERATURES WEDNESDAY IF THEY ARRIVE EARLY ENOUGH...FOR NOW HAVE TRENDED TEMPERATURES TOWARD A LATER ARRIVAL. THE REMAINDER OF THE EXTENDED IS DEPENDENT ON THE GRADUAL EROSION OF THE ZONAL FLOW AND THE EVOLUTION OF A DEVELOPING LONG WAVE TROUGH AND THE ASSOCIATED IMPENDING ARRIVAL OF COLDER WEATHER. THE TRENDS POINT TO A RETURN TO MORE NORMAL TEMPERATURES SHOULD BEGIN BY FRIDAY. HINTS AT WINTER WEATHER ON THE HORIZON WITH THE GFS AND ECMWF EACH CONTINUING TO SUGGEST SNOW POTENTIAL SOMETIME IN THE DAY 7-10 RANGE. && .AVIATION...02/06Z AREAS OF DENSE FOG HAVE DEVELOPED ACROSS CENTRAL IOWA...AFFECTING ALL SITES. EXPECT VISIBILITIES AND CEILINGS TO BE RESTRICTED DUE TO FG AND BR THROUGH 12Z WITH IFR AND LIFR CONDITIONS. CEILINGS AND VISIBILITIES MAY BE VARIABLE AT TIMES RETURNING TO VFR AND MVFR. HOWEVER...PREVAILING CONDITIONS WILL BE IFR AND LIFR THROUGH 12Z. CONDITIONS WILL GRADUALLY IMPROVE AFTER 12Z...WITH VFR CONDITIONS AT SITES NEAR 18Z. COULD AGAIN SEE BR DEVELOPMENT AT SITES AFTER 00Z TOWARDS END OF PERIOD...BUT DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE MENTION ATTM. && .DMX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ADAIR-ADAMS-APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER- BUTLER-CALHOUN-CARROLL-CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS- DAVIS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON- HANCOCK-HARDIN-HUMBOLDT-JASPER-LUCAS-MADISON-MAHASKA-MARION- MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA- TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...AWB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
300 AM CST SUN DEC 2 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM ROUGHLY GREEN BAY BACK TO THE NEBRASKA/KANSAS BORDER. ANOTHER FRONT RAN FROM A LOW NEAR KSAW BACK TO AROUND KYKN. DEW POINTS OVER THE GREAT LAKES AND MIDWEST WERE IN THE 40S AND 50S WITH 30S IN THE PLAINS. && .SHORT TERM...TODAY AND TONIGHT THE IMMEDIATE CONCERN IS FOG POTENTIAL AND THE CURRENT HEADLINES. SATELLITE TRENDS SHOW GOOD SUBSIDENCE OVER NORTHWEST/WESTERN IOWA WHICH HAS ALLOWED A LARGE EXPANSE OF DENSE FOG TO FORM IN THE MOIST AIR. SAID FOG HAS EXPANDED EASTWARD IN THE LIGHT WINDS/CONVERGENCE TO INCLUDE ROUGHLY THE NORTHWEST THIRD OF THE CWFA. BASED ON CURRENT TRENDS WITH INPUT FROM THE RAP MODEL...THE CURRENT FOG HEADLINES LOOK OK. HOWEVER...GIVEN THE EXTREMELY WARM AND MOIST AIR OVER THE CWFA THERE IS REASONABLE POTENTIAL FOR PATCHY IF NOT LOCALIZED AREAS OF FOG DEVELOPING AHEAD OF THE CURRENT FOG HEADLINES ESPECIALLY IF CLEAR POCKETS DEVELOP IN THE LOW CLOUDS. THE OVERALL SUBSIDENCE INCREASES DURING THE DAY SO CLEARING IS EXPECTED FROM WEST TO EAST DURING THE DAY. GIVEN THE EXCEPTIONALLY MILD START...MAX TEMPERATURES WILL BE WELL ABOVE NORMAL FOR EARLY DECEMBER. RECORD HIGHS APPEAR DOUBTFUL BUT KBRL MAY BE CLOSE BASED ON PROJECTED MAX TEMPERATURES. A RECORD WARM LOW WILL NOT BE REALIZED AT KDBQ BUT COULD OCCUR AT KMLI. QUIET CONDITIONS WILL BE SEEN DURING THE EVENING ACROSS THE AREA. THE WARM TEMPERATURES COMBINED WITH LIGHT WINDS AND INITIALLY CLEAR OR NEARLY CLEAR SKIES SHOULD ALLOW PATCHY FOG TO DEVELOP BY LATE EVENING ACROSS THE NORTHEAST QUADRANT OF THE CWFA. AFTER MIDNIGHT...ANOTHER INFLUX OF MOISTURE WILL MOVE BACK INTO THE AREA WHICH SHOULD INCLUDE CONSIDERABLE LOW CLOUDS. PATCHY FOG SHOULD DEVELOP OVER MOST OF THE AREA. THE NORTHEAST QUADRANT OF THE CWFA WILL HAVE LIGHT WINDS AND CLEAR SKIES THE LONGEST SO THE FOG SHOULD BECOME MORE WIDESPREAD THERE. MIN TEMPERATURES TONIGHT WILL BE ABOVE THE NORMAL MAX TEMPERATURES. ..08.. .LONG TERM...MONDAY THROUGH SATURDAY MODELS CONTINUE TO SHOW ZONAL FLOW OVER U.S. THROUGH MID WEEK WITH SOME AMPLIFICATION IN THE FLOW DEVELOPING LATE WEEK AS A BROAD H5 TROF FORMS OVER THE WESTERN AND CENTRAL U.S. IN THE NEAR TERM...RECORD OR NEAR RECORD WARMTH LOOKS ON TRACK FOR MONDAY WITH THE MODELS IN GOOD AGREEMENT MOVING UNSEASONABLY WARM AIR NORTH OUT OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AHEAD OF A COLD FRONT THAT SHOULD BE MOVING INTO THE CENTRAL IA BY MID DAY. H8 TEMPS IN THE 10C TO 15C RANGE ARE PROGGED TO BE OVER THE AREA MONDAY MORNING. A SURFACE WARM FRONT SHOULD BE NEAR THE IA/MO BORDER EARLY MONDAY AND WILL MOVE NORTH DURING THE DAY WITH SOUTH WINDS INCREASING INTO THE 15 TO 25 MPH IN THE WARM SECTOR. ADDING SOME UNCERTAINTY TO THE WARM UP WILL BE UNUSUALLY HIGH LOW LEVEL MOISTURE THAT WILL BE OVER AREA BY MONDAY MORNING. THE MOIST LOW LEVELS SHOULD RESULT IN STRATUS AS WELL AS SOME PATCHY DRIZZLE AND FOG DURING THE MORNING WHICH IS EXPECTED TO MIX OUT SOME DURING THE DAY WITH INCREASING SOUTH WINDS. SOME MOS GUIDANCE INCLUDING THE MET AND ECMWF MOS IS SUGGESTING TEMPERATURES IN THE LOW 70S SOUTH TO MID 60S NORTH FOR HIGHS. HOWEVER HAVE KEPT A DEGREE OR TWO UNDER THESE WARMER TEMPS DUE TO THE UNCERTAINTY ABOUT THE EXTENT OF THE LOW CLOUD COVER. REGARDLESS...IT WILL BE A VERY WARM DAY AND FORECAST HIGHS WILL BE WITH IN A DEGREE OR TWO OF HIGH TEMPERATURE RECORDS FOR THE 3RD. IN FACT FORECASTS HIGHS ARE WITHIN 5 OR SO DEGREES OF THE ALL TIME RECORD HIGHS FOR THE MONTH OF DECEMBER. SEE THE CLIMATE SECTION BELOW FOR DECEMBER 3RD RECORD HIGHS AND THE RECORD HIGHS FOR THE MONTH OF DECEMBER. THE FRONT AND ATTENDANT S/W WILL BRING ANOTHER CHANCE OF RAIN TO THE AREA MAINLY MONDAY AFTERNOON AND EVENING. AS WITH THE SYSTEM THAT MOVED THROUGH SATURDAY...THE MID LEVELS WILL BE DRY INITIALLY WITH VERY LITTLE SATURATION EXPECTED. WITH THE BEST FORCING EXPECTED TO MOVE THROUGH DURING THE EARLY EVENING HAVE KEPT LOW CHANCE POPS FOR THE AFTERNOON AND 50 POPS EAST OF THE RIVER MONDAY EVENING. SOME THUNDER EAST OF THE RIVER CAN/T BE RULED OUT AT THIS TIME BUT FELT THE POTENTIAL WAS TOO LOW TO INCLUDE IN THE FORECAST FOR NOW. RAINFALL AMOUNTS MONDAY AND MONDAY NIGHT SHOULD BE LIGHT...GENERALLY LESS THAN A TENTH OF AN INCH. QUIET WEATHER SHOULD BE OVER THE AREA TUESDAY AND WEDNESDAY AS HIGH PRESSURE DOMINATES THE REGION. TEMPERATURES WILL COOL OFF SOME FOR MID WEEK BUT WILL STILL BE ABOVE NORMAL. THE NEXT SYSTEM WILL START TO IMPACT THE AREA BY WEDNESDAY NIGHT AS A S/W CROSSES THE NORTHERN ROCKIES AND PUSHES A COLD FRONT INTO THE NORTH CENTRAL STATES AND CENTRAL PLAINS BY THURSDAY MORNING. HAVE GONE WITH SLIGHT CHANCE POPS FOR RAIN NORTHWEST LATE WEDNESDAY NIGHT THEN CHANCE POPS THURSDAY AND THURSDAY NIGHT AS THE SYSTEM MOVES THROUGH. THE ECMWF AND GFS ARE IN GOOD AGREEMENT WITH A BROAD UPPER TROF SETTING UP OVER THE CENTRAL U.S. FOR THE END OF THE WEEK AND PLACING A BAROCLINIC ZONE OVER THE AREA. BECAUSE OF THIS SOME LOW POPS WERE HELD ONTO FOR THE SOUTHERN CWFA INTO FRIDAY NIGHT. TEMPERATURES MAY BE COLD ENOUGH BY FRIDAY NIGHT TO PRODUCE SOME MIXED PRECIPITATION. THE DEVELOPING UPPER TROF SHOULD BRING NEAR NORMAL TEMPERATURES TO THE REGION FOR THE END OF THE WEEK. DLF && .AVIATION... /ISSUED 1130 PM CST SAT DEC 1 2012/ TREMENDOUSLY MILD AIR HAS MOVED NORTH UP OVER EASTERN IOWA AND NORTHWEST ILLINOIS. LIFR CONDITIONS AT CID AND DBQ WILL REMAIN IN PLACE THROUGH MID SUNDAY MORNING. MINIMUMS ARE LIKELY AT CID AND DBQ...1/4MI VV001...AND REMAIN POSSIBLE AT BRL AND MLI. AFTER 16Z TO 18Z SUNDAY...ANOTHER WINDOW OF VFR WEATHER IS LIKELY...AFTER WHICH MORE LOW CLOUDS AND DRIZZLE CAN BE EXPECTED LATE TOMORROW NIGHT AFTER 06Z/03. WINDS WILL BE LIGHT AND VARIABLE THROUGH THE PERIOD. ERVIN && && .CLIMATE... RECORD HIGHS FOR DECEMBER 2... MOLINE.........65 IN 1982 CEDAR RAPIDS...66 IN 1962 DUBUQUE........62 IN 1982 BURLINGTON.....66 IN 1962 RECORD WARM LOWS FOR DECEMBER 2... MOLINE.........49 IN 1913 RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGH... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR BENTON- BUCHANAN-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES- KEOKUK-LINN-WASHINGTON. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
350 PM CST SUN DEC 2 2012 .DISCUSSION... SHORT TERM FORECAST (TONIGHT AND MONDAY)... AT 21Z SURFACE OBSERVATIONS AND ASSOCIATED RAP ANALYSIS INDICATES A DECENT PRESSURE GRADIENT FORMING ACROSS EASTERN KANSAS IN RESPONSE TO A LEE SIDE SURFACE TROUGH FORMING ON THE EAST SIDE OF THE ROCKIES...OVER THE CENTRAL HIGH PLAINS. THIS PRESSURE GRADIENT HAS ALLOWED FOR SOUTHERLY FLOW TO INCREASE THROUGH OUT THE DAY AS WARM AND MOIST AIR MOVES INTO THE AREA. ALTHOUGH DEWPOINTS THROUGHOUT THE AREA ARE ONLY IN THE LOWER TO MID 40S OBSERVATIONS FROM ACROSS OK..AR..AND SOUTHERN MISSOURI INDICATE THAT A DECENT AMOUNT OF LOW LEVEL MOISTURE IN THE FORM OF UPPER 50 TO LOWER 60 DEGREE DEWPOINTS RESIDES AND IS POISED TO MAKE A SURGE NORTHWARD AS THE PREVIOUSLY MENTIONED TROUGH MOVES OFF THE HIGH PLAINS. DIFFICULT FORECAST REMAINS FOR THE OVERNIGHT HOURS AS THE MOISTURE SURGES NORTH. GIVEN THE SHALLOW NATURE OF THE GOOD MOISTURE WITH VERY DRY AIR ABOVE THE LOW LEVEL MOISTURE WILL RULE OUT MEASURABLE PRECIPITATION FOR THE OVERNIGHT HOURS...HOWEVER A LOW STRATUS DECK DOES SEEM RATHER LIKELY WITH POSSIBLY SOME VERY MINOR DRIZZLE. ALSO WILL NOT RULE OUT THE POSSIBILITY OF SOME PATCHY FOG AS SOME MODEL GUIDANCE SUGGESTS AREAS OF REDUCED VISIBILITY...ESPECIALLY ALONG AND EAST OF HIGHWAY 75. CANNOT COMPLETELY RULE OUT DENSE FOG OVERNIGHT...ESPECIALLY IN THE AFOREMENTIONED FAR EASTERN KANSAS AREAS...BUT GIVEN THE FACT THAT SOUTHERLY WINDS OF AROUND 10 TO 20 MPH WILL BE PERSISTENT FOR MUCH OF THE NIGHT THE FEELING IS THAT THE LOWER ATMOSPHERE MAY BE TOO MIXED TO CONSIDER WIDESPREAD DENSE FOG. LOW STRATUS/FOG WILL LIKELY REMAIN IN THE AREA THROUGH THE MID MORNING BEFORE MIXING GRADUALLY DISSIPATES THE STRATUS BY MID MORNING/EARLY AFTERNOON. FOR MONDAY WE CAN EXPECT ONE MORE DAY WITH TEMPS NEARLY 25 DEGREES WARMER THAN SEASONAL NORMALS. A COLD FRONT STANDS POISED TO MOVE THROUGH THE AREA DURING THE DAY ON MONDAY. ALTHOUGH THIS FRONT WILL ACT TO BRING TEMPS DOWN A FEW DEGREES IT WILL HARDLY BRING THE SURGE OF COLD AIR TYPICALLY ASSOCIATED WITH DECEMBER AS TEMPS FOR THE MIDDLE PART OF THE WEEK WILL REMAIN WELL ABOVE NORMAL. JL LONG TERM - TUESDAY THROUGH SUNDAY... TUESDAY THROUGH WEDNESDAY NIGHT - THE COLD FRONT WILL HAVE PASSED COMPLETELY THROUGH THE FORECAST AREA BY MONDAY EVENING AND ANY PRECIPITATION SHOULD HAVE SHIFTED SOUTHEAST WITH THE FRONT. COLD AND DRY ADVECTION WILL TAKE PLACE INTO TUESDAY BUT A NORTH BREEZE OVERNIGHT WILL KEEP TUESDAY MORNING LOWS IN THE 30S AND THE WARM START ALONG WITH DECENT MIXING SHOULD ALLOW AFTERNOON HIGHS TO GET INTO THE LOWER 60S. RETURN FLOW WITH SOME WARM MOIST ADVECTION WILL THEN TAKE OVER BY WEDNESDAY AS A WEAK SHORT WAVE TROUGH AND SURFACE LOW PRESSURE MOVE INTO THE NORTHERN HIGH PLAINS. WHILE TEMPERATURES ALOFT WILL BE WARMER ON WEDNESDAY...COULD SEE MORE IN THE WAY OF CLOUDS AND LESS MIXING...RESULTING IN HIGHS STILL IN THE LOWER 60S. MORE SUN COULD ALLOW HIGHS TO SNEAK INTO THE UPPER 60S IN A FEW SPOTS THOUGH. EXPECT LOW CLOUDS TO FILL IN FURTHER BY WEDNESDAY NIGHT AS THE LOW LEVEL MOISTURE INFLUX INCREASES. CLOUDS WILL KEEP LOWS WARMER. THURSDAY THROUGH FRIDAY - A COLD FRONT ASSOCIATED WITH THE NORTHERN PLAINS SHORT WAVE TROUGH WILL MOVE THROUGH THE FORECAST AREA DURING THE DAY ON THURSDAY WITH ANOTHER ROUND OF MORE SUBSTANTIAL COLD ADVECTION IN ITS WAKE. THERE WILL BE A DECENT AMOUNT OF LOW LEVEL FORCING ALONG THE FRONT AND IT WILL INTERACT WITH A FAIR AMOUNT OF GULF MOISTURE...BUT UPPER SUPPORT IS LACKING AND SUSPECT THAT THE END RESULT MAY BE SIMILAR TO THE FRONTAL PASSAGE ON MONDAY WITH THE BULK OF PRECIPITATION DEVELOPING SOUTHEAST OF THE FORECAST AREA. HAVE STILL KEPT AT LEAST A CHANCE OF SHOWERS ACROSS THE SOUTHEAST HALF OF THE FORECAST AREA FOR UNCERTAINTY IN FRONTAL TIMING AND AT LEAST THE POTENTIAL FOR EARLIER PRECIP DEVELOPMENT WHILE THE FRONT IS STILL IN THE LOCAL AREA. THE BOUNDARY SHOULD PUSH SOUTHEAST OF THE FORECAST AREA BY EARLY FRIDAY MORNING WITH A COOLER AND DRIER AIRMASS FILTERING IN. FRIDAY NIGHT THROUGH SUNDAY - UNCERTAINTY IS HIGH DURING THIS PERIOD REGARDING PRECIPITATION POTENTIAL WITH SIGNIFICANT MODEL VARIANCE. MUCH OF THE VARIABILITY IS DUE TO HOW THE FLOW PATTERN OVER THE PACIFIC OCEAN WILL EVOLVE IN THE NEXT FEW DAYS. IT DOES APPEAR THAT A TRANSITION TO A MORE SOUTHWESTERLY FLOW PATTERN OVER THE CENTRAL AND EASTERN CONUS WILL HAPPEN IN THE LONG TERM WITH MOISTURE LINGERING NOT FAR TO THE SOUTH AND OCCASIONAL DISTURBANCES INTERACTING WITH A FRONTAL BOUNDARY. HOWEVER THE TIMING OF THE DISTURBANCES AND THE LOCATION OF THE FRONT ARE VERY MUCH IN QUESTION. THE END RESULT FOR THIS FORECAST IS ACTUALLY FOR COOLER...BUT NEAR NORMAL TEMPERATURES DURING THIS PERIOD WITH SOME POTENTIAL FOR A STORM SYSTEM TO BRING PRECIPITATION TO THE REGION BY THE WEEKEND. CURRENTLY HAVE INDICATED RAIN IN THE FORECAST... BUT THERE WOULD BE AT LEAST SOME POTENTIAL FOR A BIT OF SNOW...DEPENDING ON PRECIPITATION TIMING. BARJENBRUCH && .AVIATION... LOW TO MEDIUM CONFIDENCE FORECAST FOR OVERNIGHT TO EARLY MORNING HOURS...AS A STRONG SURGE OF MOISTURE WILL AID IN THE FORMATION OF FOG ACROSS NORTHEAST KANSAS. MODEL GUIDANCE SUGGESTS A PERIOD OF IFR VIS/CIG AT KTOP...HOWEVER WITH INCREASING WINDS THE LIKELIHOOD OF DENSE FOG AT KTOP IS RATHER LOW. EVEN IN THE ABSENCE OF DENSE FOG THERE IS A GOOD CHANCE THAT LOW STRATUS WILL DEVELOP...WHICH COULD ALSO BRING A PERIOD OF IFR CONDITIONS FOR EARLY MONDAY MORNING. VFR SHOULD RETURN TO ALL TERMINALS BY MID MORNING MONDAY. JL && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1138 PM CST SAT DEC 1 2012 .UPDATE... FOG CONTINUES TO BE PRESENT ACROSS MUCH OF THE I-135 CORRIDOR AS A MOIST BOUNDARY LAYER MOVES EASTWARD ACROSS THE AREA. EXPECT TRANSIENT PATCHY DENSE FOG AT SOME LOCATIONS...BUT STILL NOT EXPECTING WIDESPREAD DENSE FOG. WILL ALLOW NEXT SHIFT TO MONITOR FOR TRENDS IF A DENSE FOG ADVISORY IS NEEDED. BILLINGS && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION FORECAST CONCERN IS MVFR/IFR AND LIFR CEILINGS DUE TO PATCHY FOG AND PATCHY DENSE FOG. MOISTURE CONTINUES TO BE PUSHED OFF EASTWARD AS DRIER AIR MOVES INTO THE REGION. HOWEVER...WITH THE CLEAR SKIES AND MOISTURE IN THE AIR EARLIER THIS EVENING SOME LOCATIONS DROPPED TO IFR AND LIFR CONDITIONS. DO THINK THIS TREND WILL DIMINISH AS THE NIGHT WARES ON WITH THE DRIER AIR CONTINUING TO PUSH EASTWARD. THINK THAT MVFR CONDITIONS WILL BE POSSIBLE WITH SOME BRIEF TRANSIENT PERIODS OF IFR OR LIFR FOR THE NEXT FEW HOURS AT KSLN/KHUT/KICT. ALSO EXPECTING MVFR TO IFR CONDITIONS TO DEVELOP OVER KCNU CLOSER TO THE MORNING HOURS WITH THE REMNANT MOISTURE OVER SOUTHEASTERN KANSAS THIS EVENING. THINGS SHOULD CLEAR OUT OVERNIGHT OUT WEST WITH VFR CONDITIONS EXPECTED DURING THE DAY SUNDAY. LOOKS LIKE LOW STRATUS AND FOG COULD DEVELOP AGAIN SUNDAY NIGHT/MONDAY TOWARD THE END OF THE TAF PERIOD AS WARM MOIST ADVECTION STREAMS NORTHWARD. BILLINGS && .PREV DISCUSSION... /ISSUED 947 PM CST SAT DEC 1 2012/ UPDATE... THERE ARE SOME AREAS OF PATCHY FOG WITH SOME LOCATIONS SEEING DENSE FOG WITH VISIBILITIES OF 1/4 TO 1/2 MILE HOWEVER...FEEL THAT THIS IS MORE TRANSIENT IN NATURE. WITH THE DRIER AIR MOVING IN AND MID-HIGH CLOUDS ALSO MOVING IN FROM THE WEST AM NOT ANTICIPATING ISSUING A DENSE FOG ADVISORY AT THIS TIME. ALSO DID UPDATE THE CURRENT FORECAST WITH TRENDS OVERNIGHT REGARDING TEMPS AND DEWPOINTS. NOT ANY BIG WHOLESALE CHANGES...JUST KEEPING IN LINE WITH TRENDS. BILLINGS PREV DISCUSSION... /ISSUED 526 PM CST SAT DEC 1 2012/ AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION CONCERN IS MVFR/IFR CONDITIONS AT KCNU AND POSSIBLY KRSL/KSLN. MOISTURE WILL REMAIN PLENTIFUL ACROSS SOUTHEASTERN KANSAS THROUGH THE EVENING AND EARLY OVERNIGHT HOURS BEFORE THE DRIER AIRMASS INFILTRATES. AS LONG AS THIS WARM/MOIST AIRMASS REMAINS IN PLACE THE POSSIBILITY FOR MVFR/IFR CONDITIONS ARE POSSIBLE AT KCNU. HAVE KEPT THE HINT AT THOSE CONDITIONS IN THE KCNU TAF AND WILL CONTINUE TO MONITOR FOR UPDATES. AT KRSL/KSLN CLEAR SKIES MAY HELP TEMPERATURES RADIATE OUT AND SOME BRIEF MVFR VISIBILITIES ARE POSSIBLE TOWARD MORNING. AGAIN THE NAM/HRRR ARE A LITTLE SLOWER IN MOVING IN THE DRIER AIR...KEEPING THIS MORE LIKELY. WILL CONTINUE TO MONITOR THIS EVENING FOR THE QUICKNESS OF THAT DRY AIR TO MOVE INTO THE AREA. BILLINGS PREV DISCUSSION... /ISSUED 233 PM CST SAT DEC 1 2012/ DISCUSSION... TONIGHT-SUNDAY NGT: THE PRIMARY PROBLEM IS FOG POTENTIAL IN SE KS WHERE A WEAK SFC TROF WILL DRIFT SE OVER THE REGION LATE TONIGHT. THE DIMINISHING SLY WINDS COUPLED WITH RICH MOISTURE AXIS SITUATED ALONG & SE OF THE TROF SHOULD PROMOTE FOG REDEVELOPMENT OVER THESE AREAS FROM ~3-10AM. BOTH NAM & HRRR DEPICT SATURATED LAYER ~300FT DEEP TRAPPED BENEATH SHARP INVERSION DURING THIS PERIOD. SUNDAY WILL BE VERY WARM AS A GRADUALLY STRENGTHENING WRN PLAINS SFC TROF INDUCES LWR-DECK FLOW TO RESUME SLY COMPONENT BY MID-DAY. STILL ANTICIPATE RECORD HIGHS TO BE SET/TIED ACROSS THE REGION...ESPECIALLY IN CNTRL & SC KS. A VERY BALMY SUNDAY NGT AWAITS NEARLY ALL AREAS AS THE EWD-DRIFTING SFC TROF INDUCES A PERSISTENT WARM/MOIST SLY FLOW OVER ALL BUT RUSSELL & BARTON COUNTIES. RECORD WARMEST LOWS ARE POSSIBLE IN SOME AREAS. MON & MON NGT: STILL ANTICIPATE A FEW -SHRA/-TSRA OCCURRING OVER SE KS MON AFTERNOON & EVENING AS A WEAK MID-LVL SHORTWAVE SCOOTS E FROM THE CNTRL/SRN ROCKIES ACROSS THE SRN PLAINS. THE WAVE WILL SWEEP A COLD FRONT SE ACROSS KS IN THE AFTERNOON & EARLY EVENING BUT THE BOUNDARY WILL NOT ENCOUNTER ANY NOTEWORTHY MOISTURE UNTIL IT VENTURES INTO SE KS. TUE-FRI NGT: QUIET WEATHER SLATED FOR ALL AREAS UNTIL THU NGT WHEN THE NEXT WEAK MID LVL SHORTWAVE VENTURES E/SE ACROSS KS. AS THE ATTENDANT COLD FRONT MOVES SE ACROSS KS AREAS OF -RA WILL DEVELOP OVER KICT COUNTRY & MAY BE MIXED WITH -SN IN CNTRL KS LATE THU NGT/EARLY FRI MORNING. AS THE MID-LVL WAVE VENTURES FURTHER E/SE IT MAY STRENGTHEN. AS SUCH A FEW -TSRA REMAIN POSSIBLE OVER SE KS ON FRI. AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU TIMING THE ENDING OF IFR STRATUS/FOG THIS AFTERNOON WILL BE THE MAIN CONCERN...AS SOUTHERLY FLOW HAS ALLOWED SHALLOW GULF MOISTURE TO MOVE NORTHWARD INTO THE AREA...RESULTING IN ANTICIPATED LOW STRATUS...WITH SOME PESKY DENSE FOG IN CENTRAL KS. EXPECT THE DENSE FOG TO SLOWLY BURN OFF ACROSS CEN KS...STRATUS WILL BE SLOW TO ERODE NORTHEASTWARD THIS AFTERNOON...AS A SURFACE WAVE TRACKS ACROSS CENTRAL KS AND SLOWLY DRIFTS SOUTHEAST WITH LIGHT/VARIABLE WINDS. SOUTH CENTRAL KS LOOKS TO BREAK OUT OF LOW CLOUDS BY MIDDAY...WITH CENTRAL AND SOUTHEAST KS TAKING MUCH OF THE DAY. SO WILL SEE A GENERAL IMPROVEMENT FROM IFR TO MVFR TO VFR AS THE AFTERNOON CONTINUES. WILL CARRY VFR FORECAST AREA WIDE TONIGHT WITH LIGHT WEST SOUTHWESTERLY WIND COMPONENT. KETCHAM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 36 72 55 69 / 0 0 0 0 HUTCHINSON 36 72 53 66 / 0 0 0 0 NEWTON 37 72 55 67 / 0 0 0 0 ELDORADO 38 71 55 69 / 0 0 0 0 WINFIELD-KWLD 37 72 57 71 / 0 0 0 0 RUSSELL 32 72 42 64 / 0 0 0 0 GREAT BEND 33 71 44 65 / 0 0 0 0 SALINA 35 73 50 66 / 0 0 0 0 MCPHERSON 36 72 53 66 / 0 0 0 0 COFFEYVILLE 40 71 59 71 / 0 0 0 20 CHANUTE 39 70 56 70 / 0 0 0 10 IOLA 39 70 56 70 / 0 0 0 10 PARSONS-KPPF 39 71 59 71 / 0 0 0 20 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1118 PM CST SAT DEC 1 2012 ...UPDATED SYNOPSIS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1114 PM CST SAT DEC 1 2012 AT 00Z SUNDAY A 500MB LOW WAS LOCATED JUST OFF THE BRITISH COLUMBIA COAST. AN UPPER LEVEL TROUGH WAS LOCATED NEAR THE BASED OF THIS UPPER LEVEL LOW JUST OFF THE COAST OF THE PACIFIC NORTHWEST. FURTHER EAST A WEAKER UPPER WAVE APPEARS TO BE NEAR WESTERN MONTANA. THIS WEAKER UPPER LEVEL SYSTEM WAS RELATED TO A 100KT 250MB JET. AT THE 700MB LEVEL, A RIDGE AXIS WAS LOCATED ALONG THE SPINE OF THE ROCKIES WITH TEMPERATURES RANGING FROM 0C TO +5C ACROSS WESTERN KANSAS AND EASTERN COLORADO. 850MB TEMPERATURES AT 00Z SUNDAY RANGED FROM +15C AT NORTH PLATTE AND DODGE CITY TO +18C AT AMARILLO. AT THE SURFACE A RIDGE OF HIGH PRESSURE WAS LOCATED ACROSS SOUTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 136 PM CST SAT DEC 1 2012 TONIGHT: FAIRLY TRANQUIL CONDITIONS ARE EXPECTED TONIGHT. HIGH LEVEL CLOUDS WILL MOVE OFF TO THE EAST THIS EVENING AND SKIES SHOULD BE CLEAR THROUGH THE OVERNIGHT HOURS. BUFKIT FORECAST SOUNDINGS, MOS GUIDANCE, THE VERY END OF THE HRRR RUN, AND THE NSSL WRF MODEL HIGHLIGHTS A CONCERN FOR PATCHY FOG TOMORROW MORNING. DEWPOINTS WILL BE LOWER THAN COMPARED TO THIS MORNING. DRIER AIR WILL ADVECT IN FROM THE NW. STILL, CONSIDERING EVERYTHING ABOVE, I HAVE INSERTED PATCHY FOG ALONG AND EAST OF HIGHWAY 283. THIS MIGHT BE ON THE LIBERAL SIDE AND MAY HAVE TO BE TRIMMED FARTHER EAST. OTHERWISE, LOWS WILL BE MAINLY IN THE 30S DEG F. TOMORROW: OTHER THAN THE AFOREMENTIONED FOG AND SOME AFTERNOON CIRRUS, TOMORROW WILL BE CLEAR WITH FULL INSOLATION. DID NOT CHANGE MAXIMUM TEMPERATURES FOR TOMORROW AS THE GRID LOOKS STILL ON TRACK WITH 12Z DATA. IT WILL BE VERY WARM TOMORROW WITH HIGHS AROUND 70 DEG F. THE AVERAGE HIGH FOR THIS TIME OF YEAR IS AROUND 48 DEG F. THESE WARM TEMPERATURES ARE A RESULT OF THE DEEPENING OF THE LEE SURFACE TROUGH ACROSS EASTERN COLORADO AND RESULTANT CONTINUED WARM AIR ADVECTION. 850 HPA TEMPERATURES AROUND 15 DEG C AND ADIABATIC MIXING STILL SUPPORT THE WARM TEMPS AT THE SURFACE. LASTLY, RH`S LOOK MARGINAL FOR TOMORROW SO NOT EXPECTING ANY FIRE WX CONCERNS ATTM. IT WILL BE BREEZY TOMORROW, BUT NOTHING OUT OF THE ORDINARY IN TERMS OF WESTERN KANSAS WIND STANDARDS (GENERALLY 12-21 KT). .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 239 PM CST SAT DEC 1 2012 FOR MONDAY, A DRY AND PROGRESSIVE UPPER LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS THE PLAINS HELPING TO PUSH A COLD FRONT ACROSS WESTERN KANSAS IN THE MORNING. WINDS WILL BE GUSTY TO 15 TO 25 MPH WITH THE COLD FRONT. HIGHS WILL STILL BE MILD IN THE 60S. FOR TUESDAY INTO THURSDAY, DRY WEST TO NORTHWESTERLY UPPER LEVEL FLOW CONTINUES ACROSS THE CENTRAL CONUS, WITH THE NEXT UPPER LEVEL SHORTWAVE TROUGH DIGGING INTO THE INTERMOUNTAIN WEST ON THURSDAY FROM THE PACIFIC NORTHWEST. HIGHS LOOK MILD AND AROUND 60 WITH SOUTHERLY FLOW AHEAD OF A LEE SURFACE TROUGH. THIS NEXT SHORTWAVE WILL MOVE ACROSS THE PLAINS ON FRIDAY WITH INCREASING MID AND UPPER LEVEL MOISTURE AND A CANADIAN COLD FRONT. A FEW LIGHT RAIN OR LIGHT SNOW SHOWERS ARE POSSIBLE, HOWEVER THE LOWER LEVELS LOOK FAIRLY DRY AND MAY BE MOSTLY VIRGA. WILL LEAVE A SMALL POP GOING IN CASE. BOTH THE GFS AND ECMWF SHOW VERY MINOR AMOUNTS IF ANY WITH HIGHS IN THE 40S. BY SATURDAY THE MODELS DIVERGE WITH THE GFS SHOWING A WARM SOUTHWESTERLY UPPER LEVEL FLOW, WHILE THE ECMWF IS SHOWING A COOLER NORTHWESTERLY FLOW ALOFT. CONSENSUS HAS HIGHS IN THE 40S WHICH LOOKS REASONABLE. OVERNIGHT LOWS THROUGH THE PERIOD LOOK TO BE IN 30S COOLING INTO THE 20S BY SATURDAY MORNING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1114 PM CST SAT DEC 1 2012 WEAK WESTERLY FLOW ACROSS WESTERN KANSAS IS EXPECTED TO CONTINUE OVERNIGHT AS THE SURFACE RIDGE AXIS SLIDES SLOWLY EAST OF THE AREA. BASED ON THE WESTERLY WINDS AND DRIER AIR FILTERING INTO WESTERN KANSAS EXPECTED VFR CONDITIONS TO PREVAIL OVERNIGHT. MAY BE A BRIEF PERIOD OF MVFR VSBYS AT ALL TAF SITES AROUND DAYBREAK BUT THIS WILL BE BRIEF SO WILL NOT INCLUDE IN THE 06Z TAFS. SURFACE TROUGH OF LOW PRESSURE WILL DEVELOP ACROSS EASTERN COLORADO DURING THE DAY ON SUNDAY. SOUTHEAST WINDS WILL DEVELOP AND INCREASE TO AROUND 15KTS DURING THE DAY AS PRESSURES FALL ALONG THE LEE OF THE ROCKIES. && .PRELIMINARY POINT TEMPS/POPS... DDC 34 71 38 65 / 0 0 0 0 GCK 33 71 36 64 / 0 0 0 0 EHA 39 72 38 64 / 0 0 0 0 LBL 36 73 35 65 / 0 0 0 0 HYS 34 71 36 62 / 0 0 0 0 P28 36 73 47 68 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...SUGDEN LONG TERM...KRUSE AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
118 AM EST SUN DEC 2 2012 .SYNOPSIS... A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TONIGHT AND LIFT NORTH THROUGH REGION ON SUNDAY WHILE LOW PRESSURE TRACKS NORTH OF THE STATE. A WEAK COLD FRONT WILL CROSS THE AREA FROM QUEBEC SUNDAY NIGHT FOLLOWED BY HIGH PRESSURE ON MONDAY. && .NEAR TERM /THROUGH TODAY/... 1240 AM UPDATE: THE ONLY SIG CHGS WERE TO EXTND THE WNTR WX ADVS FOR THE DOWNEAST AND CNTRL ZONE GROUPS ONE HR EACH TO GIVE A LITTLE ORE MARGIN IN CASE LOW LVL DAMMING HOLD ON A LITTLE LONGER IN THESE AREAS. OTHERWISE...LOADED LATEST MDNGT OBSVD SFC TEMPS AND MERGED TO 7 AM TEMPS...WHICH IMPLIES SLOWLY RISING TEMPS ACROSS THE FA FOR THE REST OF THE OVRNGT. 945 PM UPDATE: ADDED THE COAST INTO THE WINTER WEATHER ADVISORY WITH SNOW AND FZRA. RECEIVED REPORTS OF SOME LIGHT ACCUMULATION ON THE HANCOCK COUNTY COAST. EXPECTING SNOW TO CHANGE OVER TO FZRA BEFORE GOING TO RAIN LATER TONIGHT AS SOUTH WINDS WILL PUSH THE WARMER AIR IN OFF THE GULF OF MAINE. TEMPERATURES WERE ADJUSTED TO MATCH THE LATEST CONDITIONS. LAPS/RUC SOUNDINGS SHOWING THAT WARM NOSE SETTING UP ACROSS SRN MAINE W/SNOW GOING OVER TO FZRA SUCH AS IZG(FRYEBURG). THIS WARM NOSE WILL PROCEED NORTHWARD OVERNIGHT SETTING THE STAGE FOR SOME MIXED/FREEZING PRECIP IN OUR CWA BY SUNDAY MORNING. A BRIEF BURST OF SNOW IS POSSIBLE W/THE 40KT LLVL JET FCST TO MOVE IN OVERNIGHT BY THE LATEST RUC AND NAM12 WHICH ARE HANDLING THIS QUITE WELL PER THE 00Z OBS AND RADAR TRENDS. ORGNL DISC: SNOW IS EXPECTED TO SPREAD FROM SOUTH TO NORTH OVER THE AREA LATER IN THE EVENING. WARMER AIR MOVING IN FROM THE SOUTH WILL THEN CHANGE THE SNOW OVER TO RAIN...FIRST ALONG THE COAST LATER THIS EVENING...OVER CENTRAL AREAS EARLY TOMORROW MORNING AND IN THE FAR NORTH LATER TOMORROW MORNING. GROUND AND ROAD SURFACES WILL LIKELY BE BELOW FREEZING AS THE CHANGEOVER OCCURS SO A BAND OF FREEZING RAIN HAS BEEN INCLUDING ALONG THE LINE OF CHANGEOVER AND WINTER WEATHER ADVISORIES HAVE BEEN ISSUED FOR FREEZING RAIN...INITIALLY DOWNEAST BEGINNING THIS EVENING THEN OVER THE NORTH EARLY SUNDAY MORNING. BY MIDDAY SUNDAY TEMPS SHOULD HAVE RISEN ABOVE FREEZING THROUGHOUT THE AREA AS SOUTH WINDS PULL WARMER AIR ACROSS THE STATE. LOW CLOUDS...PATCHY DRIZZLE...FOG AND SOME SHOWERS WILL BE LIKELY WITH MOST OF THE SHOWERS IN THE HIGHER ELEVATIONS OF WESTERN AND NORTHERN AREAS. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... A WEAK COLD FRONT WILL MOVE FROM QUEBEC INTO THE CROWN OF MAINE SUNDAY EVENING AND SINK SOUTHWARD OVERNIGHT. THE TYPE OF PRECIPITATION WITH THIS FEATURE WILL BE ALL RAIN EVERYWHERE. LOWS WILL ONLY DIP TO THE UPPER 30S TO LOW 40S BY DAYBREAK. WITH SOME PRETTY GOOD LIFT...THE RAINFALL COULD AMOUNT TO UP TO A HALF INCH IN NORTHERN ZONES AND LESSER AMOUNTS DOWN EAST. PRECIPITATION MOVES OUT OF EASTERN MAINE EARLY MONDAY. TRANSITORY HIGH PRESSURE BUILDS DURING MONDAY WITH A NORTHWEST FLOW BUT WEAK COLD AIR ADVECTION. AS A RESULT...HIGHS WILL CLIMB TO THE LOW TO MID 40S IN NORTHERN ZONES AND UPPER 40S TO AROUND 50F DOWN EAST. SOME H925-H850 MOISTURE REMAINS BUT EXPECT SOME AFTERNOON SUNSHINE. HIGH PRESSURE CRESTS OVER THE AREA MONDAY NIGHT. WITH CLEAR SKIES AND CALM WINDS TEMPERATURES WILL DIP INTO THE MID 20S NORTH TO THE LOW TO MID 30S SOUTH. UNDER A RADIATION INVERSION...SOME FREEZING FOG COULD FORM WITH AREAS OF BLACK ICE. AS SOUTH WINDS BEGIN TO INCREASE TOWARDS TUESDAY MORNING FOG IS LIKELY TO LIFT TO LOW STRATUS. AREAS OF FOG AND LOW STRATUS MAY PERSIST INTO THE MORNING WITH MID AND HIGH LEVEL CLOUDS MOVING IN DURING THE AFTERNOON AHEAD OF THE NEXT COLD FRONT. THIS FEATURE WILL BRING A CHANCE OF RAIN BY LATE IN THE DAY HOWEVER MOST OF THE PRECIPITATION SHOULD HOLD OFF UNTIL TUESDAY NIGHT. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A COLD FRONT WILL BEGIN TO CROSS THE REGION TUESDAY NIGHT WITH RAIN SHOWERS. ACROSS NORTHWEST PORTIONS OF THE FORECAST AREA...JUST ENOUGH COLD AIR BEHIND THE FRONT COULD ALLOW THE RAIN SHOWERS TO MIX WITH SNOW SHOWERS LATE. THE COLD FRONT WILL CROSS THE REGION WEDNESDAY WITH RAIN SHOWERS IN ADVANCE OF THE FRONT AND RAIN/SNOW SHOWERS IN THE WAKE OF THE FRONT. THE FRONT WILL MOVE EAST OF THE REGION WEDNESDAY NIGHT...WITH UNCERTAINTY REGARDING LOW PRESSURE WHICH COULD POSSIBLY BEGIN TO DEVELOP ALONG THE FRONT OVER THE MARITIMES. IF THE LOW DOES NOT DEVELOP...THE FRONT WILL BE MORE PROGRESSIVE ALLOWING SNOW SHOWERS TO DECREASE ACROSS THE REGION WEDNESDAY NIGHT. IF LOW PRESSURE DOES BEGIN TO DEVELOP ALONG THE FRONT...THE FRONT COULD SLOW WITH THE LOW POSSIBLY WRAPPING PRECIPITATION BACK TOWARD EASTERN PORTIONS OF THE FORECAST AREA WHICH COULD ALLOW PRECIPITATION TO LINGER ACROSS EASTERN AREAS. HIGH PRESSURE WILL CROSS THE REGION THURSDAY. ANOTHER COLD FRONT WILL APPROACH FRIDAY...THEN CROSS THE REGION FRIDAY NIGHT INTO SATURDAY WITH SNOW SHOWERS ACROSS NORTHERN AREAS AND RAIN/SNOW SHOWERS DOWNEAST. LOW PRESSURE COULD POSSIBLY DEVELOP ALONG THE FRONT ACROSS THE GULF OF MAINE SATURDAY...WHICH COULD ALLOW FOR STEADIER PRECIPITATION DOWNEAST. TEMPERATURES SHOULD BE AT SLIGHTLY ABOVE NORMAL LEVELS WEDNESDAY/FRIDAY...WITH NEAR NORMAL LEVEL TEMPERATURES THURSDAY/SATURDAY. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... NEAR TERM: CONDITIONS WILL LOWER TO IFR FROM SOUTH TO NORTH OVERNIGHT THEN REMAIN IFR IN LOW CLOUDS ON SUNDAY. SOME LIGHT FREEZING RAIN IS EXPECTED DOWNEAST THIS EVENING AND OVER THE NORTH SUNDAY MORNING. SHORT TERM: CONDITIONS WILL BE IFR SUNDAY NIGHT IN RAIN AND LOW CLOUDS BEFORE IMPROVING TO VFR MONDAY. MORE IFR IS LIKELY MONDAY NIGHT INTO TUESDAY MORNING IN FOG AND STRATUS. THESE CONDITIONS MAY BRIEFLY IMPROVE DURING THE DAY TUESDAY BEFORE THE NEXT SYSTEM ARRIVES AT NIGHT. MVFR/IFR CONDITIONS ARE EXPECTED TUESDAY NIGHT INTO WEDNESDAY. VFR CONDITIONS ARE EXPECTED THURSDAY. && .MARINE... NEAR TERM: AN SCA HAS BEEN ISSUED FOR SOUTH WINDS INCREASING THIS EVENING AND CONTINUING THROUGH SUNDAY. SEAS WILL BUILD UP TO 8 FT IN RESPONSE TO THE SOUTH WINDS AND SOME FOG MAY LIMIT VISIBILITIES OVER THE WATERS. SHORT TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN AT SCA LEVELS UNTIL EARLY MONDAY MORNING. AFTER A BRIEF RESPITE WINDS WINDS AND SEAS WILL INCREASE AGAIN LATE TUESDAY AHEAD OF THE NEXT SYSTEM. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MEZ001-002. WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ003>006-010-011-031-032. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MEZ015>017-029-030. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR ANZ050>052. && $$ NEAR TERM...VJN SHORT TERM...FITZSIMMONS LONG TERM...NORCROSS AVIATION...VJN MARINE...VJN/FITZSIMMONS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
308 PM EST SUN DEC 2 2012 .SYNOPSIS... A WEAK FRONT WILL DISSIPATE SOUTH OF THE MASON DIXON LINE TONIGHT. HIGH PRESSURE BRIEFLY BUILDS IN MONDAY...BEFORE MOVING OFF THE COAST TUESDAY AS THE NEXT COLD FRONT APPROACHES. THE NEXT FRONTAL PASSAGE EXPECTED TUESDAY NIGHT INTO EARLY WEDNESDAY. HIGH PRESSURE RETURNS FOR THE LATER PORTION OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... AN UPPER SHORTWAVE TROUGH AND SFC LOW CURRENTLY NORTH OF THE GREAT LAKES WILL TRACK EWD INTO NRN NEW ENGLAND TNGT. ATTENDANT COLD FRONT STRETCHES SEWD INTO THE UPPER MIDWEST. SWLY LOW- AND MID-LVL JET IN PRE-FRONTAL WARM SECTOR HAS DRAWN A NARROW PLUME OF MOISTURE /WHERE PWATS ARE AOB 1 INCH/ STREAMING UP THE WRN SIDE OF THE APPALACHIANS. A BAND OF SHOWERS WITHIN THIS PLUME/LLVL JET IS CURRENTLY CROSSING THE ALLEGHENY FRONT. THE SRN PORTION OF THE FRONT WILL DISSIPATE TNGT AS IT PROGRESSES EWD TOWARD THE MID-ATLANTIC REGION AND BECOMES EMBEDDED IN INCREASINGLY ZONAL FLOW. THEREFORE...THE BAND OF SHOWERS SHOULD WEAKEN AND ACQUIRE A MORE ZONAL TILT AS IT CROSSES THE MTS. MEASURABLE PRECIP THRU THIS EVE WILL BE LIKELY OVER THE MTS AND IN NORTH-CENTRAL MD. POPS DECREASE TO CHANCE CAT FARTHER SOUTH AND EAST. LATEST HRRR SHOWS THE BULK OF THE PRECIP CLEARING THE REGION BEFORE MIDNIGHT...ALTHOUGH SCT SHOWERS MAY LINGER INTO THE OVNGT ALONG THE WRN SLOPES OF THE ALLEGHENY FRONT. QPF AMOUNTS GENERALLY UNDER ONE-TENTH INCH EXCEPT IN THE WRN HIGHLANDS. NW FLOW ALOFT WILL FILTER IN MID-LVL DRY AIR. NOT SURE HOW MUCH DRYING WILL OCCUR IN THE BOUNDARY LAYER...BUT THE HIGHEST PROBABILITY FOR CLEARING OVNGT WILL BE ACROSS NRN MD. IF CLEARING DOES OCCUR...DEVELOPMENT OF FOG AND STRATUS WILL BECOME FAVORABLE. THIS CONDITIONAL SETUP NOT AS FAVORABLE FOR FOG THAT IS AS WIDESPREAD/DENSE AS THIS MRNG. MIN TEMPS GENERALLY IN THE 40S... ALTHOUGH TEMPS MAY BOTTOM OUT A FEW DEGREES MORE THAN ADVERTISED IF CLEARING OCCURS EARLIER. HIPRES/UPPER RIDGE BUILDS INTO THE AREA MON. MOISTURE HUNG UP ALONG THE OLD FRONTAL BOUNDARY MAY KEEP CLOUDS IN THE AREA ESPECIALLY OVER THE MTS /EVEN AFTER ANY MRNG STRATUS MIXES OUT/. DESPITE THE CLOUD COVER...MAX TEMPS IN THE 60S CAN BE EXPECTED. HIGHS APPROACH 70F IN CENTRAL VA. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... HIGH PRESSURE MOVES OFFSHORE MONDAY NIGHT AS A COLD FRONT MOVES INTO THE OHIO VALLEY. THE FRONT WILL MOVE THROUGH MOST OF THE CWFA BY TUESDAY NIGHT. POPS REMAIN HIGHEST ALONG AND WEST OF THE BLUE RIDGE AND ALONG THE MASON DIXON LINE TUESDAY NIGHT. THIS IS CONSISTENT WITH PREVIOUS MODEL RUNS. HOWEVER...POPS HAVE CONTINUED TO INCREASE OVER THE SE CWFA FROM RUN TO RUN...BUT PROBABILITIES STILL REMAIN IN THE LOW CHANCE CATEGORY. TEMPERATURES ARE EXPECTED TO BE NEAR 20 DEGREES ABOVE NORMAL DURING THE DAY ON TUESDAY. MIN TEMPS TUESDAY NIGHT SHOULD REMAIN IN THE 40S TO LOWER 50S IN MOST LOCALES...SOME 10-12 DEGREES ABOVE NORMAL. PTYPE IS NOT EXPECTED TO BE AN ISSUE...WITH ALL RAIN FORECAST. && .LONG TERM (WEDNESDAY THROUGH SUNDAY)... COLD FRONT STILL ACROSS LOWER SOUTHERN MARYLAND EARLY WEDNESDAY MORNING...BUT SHOULD MOVE SOUTH OF THE AREA BY MIDDAY. SHOWERS WILL DECREASE ACROSS THIS AREA THROUGH LATE MORNING. HIGH PRESSURE WILL BRIEFLY BUILD IN FOR THURSDAY...BUT MOVE OFFSHORE ON FRIDAY WITH RETURN FLOW SETTING UP. POPS BEGIN TO INCREASE FRIDAY NIGHT AS AN UPPER DISTURBANCE MOVES ACROSS THE REGION. IN ADDITION...ISENTROPIC LIFT SHOULD ALSO BEGIN TO INCREASE ACROSS THE MID ATLANTIC AS A WARM FRONT BEGINS TO PUSH NORTHWARD SATURDAY. MODELS HAVE SLOWED DOWN THE APPROACH OF THE COLD FRONT TO SUNDAY. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... MID-LVL CLOUDS WILL THICKEN FROM WEST TO EAST LATE THIS AFTN AS A FRONTAL BOUNDARY APPROACHES FROM THE WEST. A FEW SHOWERS POSSIBLE LATE THIS AFTN AT MRB AND ERY TO MID EVE AT THE OTHER TERMINALS. MAINLY VFR CIGS/VSBYS EXPECTED THIS EVE. CONCERN WILL BE IF/WHEN CLOUDS CLEAR OUT. IF THEY OCCUR EARLY ENOUGH /I.E. OVNGT/ THEN LOW CLOUDS AND FOG COULD DEVELOP. ALL TERMINALS FCST TO SEE AT LEAST MVFR REDUCTION TOWARD MRNG. THE NRN TERMINALS WILL HAVE THE BEST CHANCE TO EXPERIENCE CLEARING AND THUS IFR CIGS/VSBYS. A COLD FRONT WILL MOVE THROUGH THE MIDDLE ATLANTIC TUESDAY NIGHT INTO EARLY WEDNESDAY. SUB VFR CONDITIONS EXPECTED WITH SCT/NMRS SHOWERS AND POSSIBLY SOME FOG. HIGH PRESSURE BUILDS IN FOR THURSDAY...BUT MOVES OFFSHORE ON FRIDAY. && .MARINE... SLY FLOW 10-15 KT THRU THE EVE. DESPITE 20-25 KT WINDS JUST ABOVE THE SFC...COOL WATER TEMPS SHOULD PREVENT THESE STRONGER WINDS FROM REACHING THE SFC. WILL NEED TO WATCH FOR SLY CHANNELING THRU THE EVE...WHICH COULD LOCALLY/BRIEFLY ENHANCE WINDS TO NEAR SCA LVLS. WINDS SHIFT OUT OF THE NW OVNGT AND MON ONCE A FRONTAL BOUNDARY PASSES THRU. LGT WINDS EXPECTED WITH THE NW FLOW. A COLD FRONT WILL CROSS THE WATERS LATE TUESDAY INTO EARLY WEDNESDAY...ACCOMPANIED BY SCT/NMRS SHOWERS. HIGH PRESSURE BUILDS IN FOR THURSDAY...BUT MOVES OFFSHORE FRIDAY SETTING UP RETURN FLOW. THE NEXT FRONT LOOKS TO IMPACT THE WATERS BY LATE NEXT WEEKEND. SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY AFTERNOON AND NIGHT BEHIND THE COLD FRONT AS NORTHERLY FLOW CHANNELS DOWN THE BAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ KLEIN/LISTEMAA
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
238 AM EST SUN DEC 2 2012 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFF THE EASTERN SEABOARD OVERNIGHT. A WEAK COLD FRONT WILL MOVE ACROSS THE REGION LATE SUNDAY INTO EARLY MONDAY. HIGH PRESSURE WILL BUILD ACROSS THE AREA LATE MONDAY INTO EARLY TUESDAY...WITH THE NEXT FRONTAL BOUNDARY EXPECTED LATE TUESDAY INTO EARLY WEDNESDAY. HIGH PRESSURE RETURNS FOR THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TODAY/... THICKEST FOG DVLPD OUTSIDE ADVY AREA...INVOF HGR/MRB. HV ADDED THAT AREA TO DENSE FOG ADVY...AND EXPANDED EVERYTHING TIL 9AM CONSIDERING SUN ANGLE. PRVS DSCN FOLLOWS. FULL DSCN SHORTLY. -HTS MAIN CONCERN IS WITH DENSE FOG POTENTIAL FOR THE OVERNIGHT PERIOD. LATEST 01Z LAMP GUIDANCE SUGGESTS SOME POCKETS OF HALF MILE FOG MAINLY ALONG THE WESTERN SHORE OF THE BAY AND A FEW AREAS EAST OF THE BLUE RIDGE. LATEST 01/23Z HRRR 3KM MODEL GUIDANCE IS MORE PESSIMISTIC AND HAS 1/4 MILE VSBYS PRETTY MUCH EVERYWHERE EAST OF THE BLUE RIDGE. LATEST OBS MAINLY IN 3-5SM RANGE...WITH A COUPLE OF SFC SITES IN SOUTHERN ST. MARYS COUNTY DOWN TO 1/4 MILE. WEAK EASTERLY FLOW AT THE SURFACE STILL EVIDENT ACROSS THE REGION AS THE WEAK...DIFFUSE FRONT IS STILL ALONG THE APPLACHAINS. ONE FACTOR GOING AGAINST DENSE FOG IS SOME HIGH CLOUDS EXPECTED TO STREAM IN LATE TONIGHT. BUT THINK THEY WILL BE TOO LATE TO HALT FOG PRODUCTION. GIVEN ABUNDANT LOW LEVEL MOISTURE...AND GUIDANCE SHOWING 1/4 MILE FOG A LIKELY BET...WILL ISSUE A DENSE FOG ADVISORY FOR TONIGHT FOR AREAS ALONG AND EAST OF THE BLUE RIDGE TO THE CHESAPEAKE BAY. ON SUN...AFTER A PERIOD OF EARLY MORNING FOG...EXPECT SOUTHERLY WINDS TO SCOUR OUT REMAINING FOG BY LATE MORNING. 850 HPA TEMPS EXPECTED TO BE IN THE RANGE OF 3-5 DEGC WARMER THAN TODAY. GIVEN DECENT AFTERNOON MIXING...EXPECT WARMER TEMPS FOR SUN THAN WHAT WAS EXPECTED TODAY. HOWEVER...SHOULD SOME AREAS REMAIN FOG SHROUDED LONGER...TEMPS WILL CERTAINLY BE A BIT COOLER THAN WHAT IS ADVERTIZED...MAX TEMPS RANGING FROM THE LOW/MID 50S NORTH- CENTRAL MD TO MID 60S IN CENTRAL VA. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... A WEAK COLD FRONT WILL APPROACH THE MASON DIXON LINE BY 00Z MONDAY AND DISSIPATE AS IT PUSHES SOUTH OVER THE CWFA. MODELS DO AGREE THE BEST CHANCES OF PRECIP WILL BE IN THE HIGHLANDS AND ALONG THE MASON DIXON LINE. HAVE ADJUSTED POPS AND TIMING DURING THIS PERIOD. TEMPS LOOK WARM ENOUGH THAT THERE SHOULDN`T BE ANY PTYPE ISSUES. POPS LOOK LOW ACROSS THE FAR SE CWFA AT THIS TIME...SO WILL LEAVE OUT ANY MENTION OF PRECIP AT THIS TIME. && .LONG TERM /TUESDAY THROUGH SATURDAY/... HIGH PRESSURE WILL REMAIN OFF THE SE COAST ON TUESDAY AS A COLD FRONT APPROACHES FROM THE OHIO VALLEY. THE FRONT SHOULD PUSH THROUGH THE CWFA LATE TUESDAY INTO EARLY WEDNESDAY...ACCOMPANIED BY SCATTERED SHOWERS. TEMPERATURES WILL RANGE 10 TO 15 DEGREES ABOVE NORMAL TUESDAY AND TUESDAY NIGHT. TEMPS WILL BE WARM ENOUGH FOR ALL RAIN...EVEN AT THE HIGHER ELEVATIONS. HIGH PRESSURE RETURNS FOR THURSDAY...BUT SHOULD MOVE OFFSHORE ON FRIDAY AHEAD OF THE NEXT FRONTAL SYSTEM. THE FRONT IS EXPECTED TO IMPACT THE AREA DURING THE WEEKEND. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... PD OF LIFR XPCTD THRU SUNRISE FOR IAD/DCA/BWI. DENSEST FOG THUS FAR ACTUALLY AT MRB. WL AMD THAT TAF SHORTLY. EXPECT CONDITIONS IMPRVG BY 13-14Z ABOVE IFR TO VFR BY 15Z. MVFR CONDITIONS POSSIBLE LATE SUNDAY NIGHT/EARLY MONDAY AS A WEAK COLD FRONT APPROACHES THE MASON DIXON LINE. THE NORTHERN TERMINAL SITES WILL BE THE MOST LIKELY TO HAVE CIGS/VSBYS REDUCED IN SCT SHOWERS. A SECOND COLD FRONT IS EXPECTED TUESDAY NIGHT INTO WEDNESDAY... BRINGING ANOTHER ROUND OF SCT SHOWERS. && .MARINE... LIGHT EASTERLY FLOW OR CALM CONDITIONS OVER THE WATERS TONIGHT. SOME AREAS OF FOG BELOW 1 NM EXPECTED. ON SUNDAY...SOUTHERLY FLOW WILL SET UP...BUT WINDS EXPECTED TO BE LESS THAN 10 KTS MARINE WIDE. A WEAK COLD FRONT WILL APPROACH THE MASON DIXON LINE LATE SUNDAY NIGHT INTO EARLY MONDAY AND DISSIPATE AS IT PUSHES SOUTH ACROSS THE NORTHERN WATERS. A SECOND COLD FRONT IS EXPECTED TO IMPACT THE REGION TUESDAY NIGHT INTO EARLY WEDNESDAY. HIGH PRESSURE RETURNS FOR THURSDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR DCZ001. MD...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MDZ003>007- 009>011-013-014-016>018. VA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ040-042- 051>055-501-502. WV...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ051>053. MARINE...NONE. && $$ SYNOPSIS...SMZ NEAR TERM...HTS/SMZ SHORT TERM...NWL LONG TERM...NWL AVIATION...HTS/SMZ MARINE...SMZ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
642 PM EST MON DEC 3 2012 .SYNOPSIS... ISSUED AT 330 PM EST MON DEC 3 2012 AN APPROACHING COLD FRONT WILL INTERACT WITH AN UNSEASONABLY WARM AND MOIST AIR MASS TO PRODUCE RAIN SHOWERS AND A FEW THUNDERSTORMS TONIGHT. DECREASING CLOUDS WILL FOLLOW ON TUESDAY BEHIND THE DEPARTING FRONT... AND HIGH PRESSURE WILL SETTLE OVER THE REGION ON WEDNESDAY. ALTHOUGH IT WILL COOL DOWN BEHIND THE COLD FRONT... TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE REST OF THE WEEK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 330 PM EST MON DEC 3 2012 UNSEASONABLY WARM/MOIST AIR MASS CONTINUES SURGING NORTH THIS AFTERNOON... WITH READINGS NOW IN THE 60S OVER IN SW LWR MI AND DEW POINTS AROUND 60. SOME INSTABILITY IS SHOWING UP AS WELL... WITH MU CAPES OF 500 TO 1000 J/KG NOW OVER WI/IL AND LK MI. THE PRIMARY THREAT OF SHOWERS AND A FEW TSTMS WILL COME LATER THIS EVENING WITH THE COLD FRONT... BUT CAN/T RULE OUT A FEW ISOLATED CELLS DEVELOPING BETWEEN NOW AND THEN WITHIN THE STRONG WARM ADVECTION CORRIDOR NOW NUDGING INTO THE REGION FROM THE SOUTHWEST. THE LOW LEVEL JET AHEAD OF THE FRONT IS PROGGED TO INCREASE TO 50 TO 55 KTS BY 03Z... WHICH MAY SUPPORT SOME HEALTHY WIND GUSTS FROM ANY DEEPER CONVECTION WHICH DEVELOPS OR MOVES INTO THE REGION FROM THE WEST THIS EVENING. THE BULK OF THE RAIN WITH THE FRONT SHOULD BE OVER BY 12Z TUESDAY WITH THE EXCEPTION OF THE SE CWFA WHERE MORNING SHOWERS ARE STILL LIKELY AROUND JACKSON. OTHERWISE EXPECT DECREASING CLOUDS FROM WEST TO EAST AS STRONG DRYING/SUBSIDENCE SWEEPS IN BEHIND THE FRONT. BRIEF SHOT OF NW FLOW COLD ADVECTION MAY PRODUCE A FEW LAKE EFFECT FLURRIES TUESDAY NIGHT BEFORE THE SFC HIGH BUILDS IN FOR WEDNESDAY. WARM ADVECTION COMMENCES ALREADY AGAIN ON WEDNESDAY NIGHT AS THE HIGH SLIPS AWAY. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 330 PM EST MON DEC 3 2012 DRY WX WITH SEASONABLY MILD TEMPS IS ANTICIPATED THURSDAY MORNING AND AFTERNOON BEFORE THE APPROACHING COLD FRONT BRINGS A CHC OF MIXED LIGHT RAIN AND LIGHT SNOW SHOWERS LATE THURSDAY NIGHT INTO FRIDAY. A FEW LIGHT SNOW SHOWERS/FLURRIES ARE POSSIBLE SATURDAY TO THE NORTH OF THE WARM FRONT OVER THE LOWER GREAT LAKES REGION. THE WARM FRONT SHOULD MAKE A PUSH NORTHWARD IN ADVANCE OF A DEVELOPING LOW PRESSURE SYSTEM SATURDAY NIGHT AND SUNDAY WHICH WILL BRING RAIN SHOWERS FOR SUNDAY. CANNOT RULE OUT SOME WET SNOW FLAKES MAINLY NORTH OF I-96 SUNDAY BUT OVERALL MEDIUM RANGE GUIDANCE HAS TRENDED A LITTLE MILDER FOR SUNDAY. TEMPS WILL CONTINUE TO AVERAGE ABOVE NORMAL FRIDAY THROUGH THE WEEKEND BEFORE RETURNING TO NEAR NORMAL BEHIND THAT SYSTEM FOR EARLY NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 642 PM EST MON DEC 3 2012 THE IFR CIGS/VSBY WILL BRIEFLY BREAK OUT THIS EVENING AS MIXING AHEAD OF THE COLD FRONT PUSHES THE LOW CLOUDS AND FOG NORTHWARD OUT OF THE AREA BEFORE THE RAIN WITH THE FRONT MOVES IN. THIS IS SHOWN BY BOTH THE NAM AND RAP MODELS. SURFACE OBS SHOW THIS TREND TOO AS SBN...LWA...BIVA AND NOW MKG HAVE LOST ALL LOW CLOUDS AND VSBY ARE 10SM. THE FRONTAL RAIN BAND WILL CONTINUE TO DEVELOP OVER TIME THIS EVENING AS THE FRONT PUSHES TOWARD SOUTHWEST LOWER MICHIGAN. MODEL SOUNDING SHOW A SIGNIFICANT LACK OF MID LEVEL MOISTURE (ABOVE 10000 FT AGL) AS THE RAIN BAND MOVES THROUGH THE AREA. HOWEVER LATER THIS EVENING AS THE JET ENTRANCE REGION GETS CLOSER TO THE FRONT THE LIFT IMPROVES AND SO THEN DOES THE DEEP MOISTURE. HOWEVER BY THEN THE RAIN BAND SHOULD FOR THE MOST PART BE THROUGH THE TAF SITES. THIS MEANS TO ME THE RAIN SHOULD NOT BE ALL THAT HEAVY SO I DID NOT LOWER THE VSBY BELOW 3 MILES WITH THE SHOWERS. ISOLATED THUNDERSTORMS ARE POSSIBLE AS THERE IS SOME MARGINALLY POSITIVE CAPE BUT IT IS VERY NARROW AND IN THE AREA WITH DRY MID LEVEL AIR. ALSO ONCE AGAIN THE BETTER JET DYNAMICS TO NOT GET HERE UNTIL THE CONVECTIVE LINE IS EAST OF HERE. EVEN SO THERE IS 40 TO 50 KNOTS IN THE BOUNDARY LAYER THIS EVENING SO ANY SHOW COULD BRING DOWN GUSTY WINDS BUT THE SOUNDINGS SHOW THE LOW LEVELS WILL BE MOIST. THAT TYPICALLY IS NOT CONDUCIVE TO BRINGING DOWN THE STRONGER WINDS IN THE 1000 TO 5000 FT LAYER. SO I HAVE VCTS IN TAFS AS THE DID THE PREVIOUS FORECAST... IT STORMS DO IN FACT DEVELOP I WILL UPDATE THE TAFS TO INCLUDE THEM. SHOULD BE BRIEF PERIOD OF LOW CLOUDS WITH THE COLD FRONT (AGAIN BASED NO MODEL SOUNDING) BUT THIS TIME THEY SHOULD QUICKLY CLEAR AFTER THE FRONT COMES THROUGH SO I HAVE ONLY MID CLOUDS AFTER 12Z AT THE TAF SITES. && .MARINE... ISSUED AT 330 PM EST MON DEC 3 2012 AREAS OF DENSE FOG WERE STILL IMPACTING THE LK MI NEARSHORE PER THE WEB CAM ON THE MUSKEGON PIER. HOWEVER VISIBILITIES WERE DECENT AT OTHER MARINE SITES. THE FOG SHOULD BECOME LESS OF AN ISSUE AS THE EVENING PROGRESSES. A SMALL CRAFT ADVISORY IS CURRENTLY IN EFFECT DUE TO THE STRONG SOUTH FLOW AHEAD OF THE FRONT. WHILE THERE MAY BE A BRIEF LULL TUESDAY MORNING ALONG AND JUST BEHIND THE FRONT... WEST NORTHWEST FLOW IS EXPECTED TO PICK UP AGAIN LATER TUESDAY INTO TUESDAY NIGHT. HAVE THEREFORE EXTENDED THE SMALL CRAFT ADVISORY THROUGH WEDNESDAY MORNING. && .HYDROLOGY... ISSUED AT 330 PM EST MON DEC 3 2012 ALTHOUGH SOME LOCALIZED RAIN AMOUNTS IN EXCESS OF 0.50 ARE POSSIBLE TONIGHT... BASIN AVERAGE RAINFALL IS EXPECTED TO BE AROUND 0.25 INCH. THIS WILL HAVE LITTLE TO NO IMPACT ON THE RIVERS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST WEDNESDAY FOR LMZ844>849. && $$ SYNOPSIS...MEADE SHORT TERM...MEADE LONG TERM...LAURENS AVIATION...WDM HYDROLOGY...MEADE MARINE...MEADE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
417 AM CST SUN DEC 2 2012 .DISCUSSION... RESTRICTED VISIBILITY FROM THE FOG/FREEZING FOG WILL GRADUALLY IMPROVE THIS MORNING...WITH TEMPERATURES RISING ABOVE FREEZING BY THE NOON HOUR ACROSS THE ENTIRE CWA. SOUTHERLY WINDS WILL INCREASE TODAY WITH VERY WARM TEMPERATURES THROUGH MONDAY. A COLD FRONT WILL MOVE THROUGH AND COOL THINGS DOWN 10 TO 15 DEGREES FOR THE MIDDLE OF THE WEEK...WITH A REINFORCEMENT OF COLD AIR ON THURSDAY BRINGING TEMPERATURES CLOSER TO THE SEASONAL AVERAGE BY THE END OF THE WEEK. NO SIGNIFICANT PRECIPITATION IS EXPECTED DURING THE NEXT FEW DAYS. TODAY THROUGH MONDAY...EARLY MORNING WV IMAGERY TOGETHER WITH 500MB HEIGHTS DEPICTED THE PREVALENT ZONAL FLOW ACROSS THE CONUS..WITH A LARGE UPPER LEVEL TROUGH CRASHING ONSHORE THE PACIFIC NORTHWEST BRING FLOODING RAINS ACROSS THE REGION...WITH HEAVY SNOW IN THE HIGHER ELEVATIONS OF THE ROCKIES. AS THIS STORM SYSTEM MOVES EAST IT WILL TRACK NORTH OF THE US/CANADA BORDER AND DEVELOP A SIGNIFICANT SNOWSTORM ON THE NORTHERN SIDE. HOWEVER...THE COLD AIR WILL BE WELL DISPLACED NORTH OF THE INTERNATIONAL BORDER...LEADING TO TWO MORE DAYS OF SEASONABLY WARM WEATHER WITH HIGH TEMPERATURES EXCEEDING 20 DEGREES ABOVE NORMAL. SOME LIGHT PRECIP IS POSSIBLE AS THE COLD FRONT MOVES THROUGH FROM THE NORTHWEST ON MONDAY...BUT THERMAL PROFILES ARE WARM ENOUGH THAT ALL PRECIP WILL BE IN LIQUID FORM. THE LACK OF SIGNIFICANT SYNOPTIC SCALE FORCING MEANS THAT ONCE AGAIN ONLY LIGHT RAINFALL TOTALS ARE EXPECTED...WITH ACCUMULATIONS ONLY AROUND A FEW HUNDREDTHS. TUESDAY THROUGH SATURDAY...THE POST FRONTAL AIR IS FAR FROM ARCTIC...WITH TUESDAY AND WEDNESDAY HIGHS STILL RUNNING 5 TO 10 DEGREES ABOVE CLIMATOLOGY. BIGGEST CHANGE TO THE FORECAST WAS LOWERING TUESDAY NIGHT LOW TEMPERATURES BELOW FORECAST GUIDANCE. UPPER LEVEL SUBSIDENCE BENEATH THE UPSTREAM RIDGE AXIS WILL CAUSE A SURFACE HIGH TO BUILD ACROSS THE REGION WHICH SHOULD PROMOTE EXCELLENT RADIATIONAL COOLING BEFORE THE SOUTHERLY WINDS PICK UP ON WEDNESDAY AHEAD OF THE NEXT APPROACHING WAVE. HOWEVER...LOW TEMPS MAY STILL BE TOO WARM...ESPECIALLY CONSIDERING THE FACT THAT THEY ARE STILL ABOVE CLIMO. THEREFORE WOULD NOT BE SURPRISED TO SEE TEMPS CLOSER TO THE LOW TEENS AS COMPARED TO THE MID AND UPPER TEENS CURRENTLY FORECAST. THE OTHER CONCERN WAS TRYING TO DETERMINE THE PTYPE ON WEDNESDAY NIGHT/THURSDAY. THE 02.00 GEM...ECMWF...AND GFS ALL HAVE H850 TEMPS OF +2 TO +4C OVERNIGHT...WITH GFS BUFR SOUNDINGS SHOWING EVEN WARMER TEMPERATURES AROUND 900MB. THEREFORE EXPECTING ANY PRECIP THAT FALLS TO MELT BEFORE IT REACHES THE SURFACE. HAVE OPTED TO INCLUDE A RA/FZRA MIX FOR NOW...SINCE SURFACE TEMPS MAY FALL BELOW FREEZING OVERNIGHT WEDNESDAY/EARLY THURSDAY MORNING. QPF AMOUNTS WILL BE LIGHT. THIS WAVE WILL DRIVE ANOTHER COLD FRONT THROUGH THE REGION...WHICH WILL HAVE A MORE SIGNIFICANT TEMPERATURE CHANGE. HIGHS ON FRIDAY AND SATURDAY WILL RANGE FROM THE MID 20S TO LOWER 30S...WHICH IS RIGHT WHERE WE SHOULD BE FOR THIS TIME OF YEAR. && .AVIATION.../06Z TAF ISSUANCE/ SEE UPDATE SECTION ABOVE FOR MANY ISSUES SURROUNDING FG. CURRENT TAFS HAVE A PRETTY GOOD HANDLE ON THINGS AT THE MOMENT. PLENTY OF LOW LEVEL MOISTURE /OUTSIDE OF SW MN/ AND LIGHT WINDS WILL RESULT IN EXPANSION OF STRATUS AND FG AS MID CLOUDS ASSOCIATED WITH POTENT SHORTWAVE NEAR MSP QUICKLY MOVE EAST. LOW CLOUDS WILL LINGER INTO THE MORNING...BUT INCREASING SRLY WINDS AND INFLUX OF DRIER AIR SHOULD LEAD TO RAPID IMPROVEMENTS IN CONDITIONS BETWEEN 14Z AND 15Z FOR MN AND POSSIBLY AS LATE AT 17Z OVER IN WI WHERE WINDS WILL REMAIN CALM. ONCE THE FOG BURNS OFF...IT WILL BE VFR CONDS WITH INCREASING S/SE WINDS AS A DEEP AREA BEGINS MOVING ACROSS SRN CAN...WITH A STRONG COLD FRONT APPROACHING WRN MN BY 12Z MON. MAIN QUESTIONS FOR TAFS TONIGHT LIES WITH AXN AND RWF. FOR AXN...STRATUS/FG DECK IS ABOUT TO MOVE IN WITH CONDITIONS VARYING FROM 200 FEET AND 1/4SM TO 1K FT AND 3SM. FOR NOW...PLAYED THE IFR CIG/VIS ROUTE...BUT IT COULD EASILY BE 1/4SM AND 200 FT LIKE FFM CURRENTLY HAS. AT RWF...DRIER HAS FOUND ITS WAY THERE AND VIS FORECASTS FROM BOTH THE GFSLAMP AND HRRR KEEP THE FOG TO THE NORTH AND EAST...SO WENT OPTIMISTIC THERE. KMSP...MID CLOUDS BEGINNING TO CLEAR THE AREA AND AS THEY MOVE EAST...FOG FORMATION SHOULD BEGIN QUICKLY OUTSIDE OF THE URBAN HEAT ISLAND. BIG QUESTION FOR FOG THOUGH IS WINDS. 1-MINUTE WIND DATA HAS SHOWN FAIRLY PERSISTENT W-NW WINDS AROUND 5 KTS AND IF THIS CONTINUES TO BE THE CASE...DENSE FOG WILL BE UNLIKELY AT THE FIELD AS THINGS DRAIN INTO THE MN VALLEY. CONTINUED WITH THE TEMPO GROUP...THOUGH LOWERED THE VIS TO 1/2SM. WITH TEMP/DEWP DEPRESSION AT 0 DEGS AT 06Z...COULD SEE THAT TEMPO NEEDING TO BE THE PREVAILING GROUP. AFTER THE MORNING FG/STRATUS CLEARS OUT...REST OF THE TAF IS PRETTY STRAIGHT FORWARD. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE. CHANCE OF -RA. WIND S AT 10 KTS BECOMING WNW AT 15-20 KTS WITH LATE AFTERNOON FRONTAL PASSAGE. TUE...VFR. WIND NW AT 10-15 KTS. WED...VFR. WIND SE AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ANOKA- BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA- DOUGLAS-FARIBAULT-HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON- NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE- SIBLEY-STEARNS-STEVENS-SWIFT-TODD-WASECA-WASHINGTON- WATONWAN-WRIGHT-YELLOW MEDICINE. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR FREEBORN- GOODHUE-STEELE. WI...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR BARRON- POLK-RUSK-ST. CROIX. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR CHIPPEWA-DUNN- EAU CLAIRE-PEPIN-PIERCE. && $$ JRB/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1200 AM CST SUN DEC 2 2012 .UPDATE... 06Z AVIATION DISCUSSION ADDED BELOW. UPDATE ON THE FOG POTENTIAL TONIGHT. /ISSUED 933 PM CST SAT DEC 1 2012/ MANY QUESTION STILL EXIST WITH THE FOG TONIGHT...WITH MULTIPLE SOURCES OF UNCERTAINTY ACROSS THE AREA. 1. SW MN. HERE...DRIER AIR WITH DEWPOINTS SLOWLY FALLING INTO THE 20S HAS OCCURRED HERE. GFSLAMP ALONG WITH HRRR VSBY FORECASTS SHOW SW MN REMAINING WITH VSBYS IN EXCESS OF 3 MILES. THE QUESTION BECOMES...HOW FAR EAST DOES THIS DRIER AIR MAKE IT. THE HRRR BRINGS IT CLEAR OVER TO THE I-35 CORRIDOR...WHILE THE GFSLAMP BRINGS THE DENSE FOG AS FAR WEST AS A FAIRMONT...LITCHFIELD... LITTLE FALLS LINE. GIVEN MKT HAS ALREADY BEEN DOWN TO 1/2SM...WOULD FAVOR THE GFSLAMP. THIS STILL KEEPS A LOT OF QUESTIONS GOING FOR LOCATIONS WEST THOUGH. 2. CENTRAL MN. A DIFFERENT ISSUE UP HERE DEALS WITH STRATUS DROPPING DOWN FROM NRN MN. RAP 925 MB RH WOULD BRING THESE CLOUDS CLEAR DOWN TO RWF...AND IF THIS HAPPENED...MUCH OF OUR NORTHERN CWA WOULD SEE ANOTHER NIGHT OF LOW STRATUS WITH MAINLY 1-3 MILE VSBYS. 3. WESTERN WI. ANOTHER STRATUS ISSUE HERE. THIS WOULD BE THE STRATUS THAT HAS BEEN SLOWLY PUSH CLEAR OF ERN MN THIS EVENING. THE RAP ALONG WITH THE HRRR SHOW THESE CLOUDS PUTTING ON THE BREAKS AS THE LOW LEVEL WIND FIELD BACKS OFF. EAU CLAIRE AND LADYSMITH WOULD HAVE THE GREATEST POTENTIAL OF NOT LOSING THE STRATUS AND ENDING UP WITH LOW STRATUS AS OPPOSED TO FOG. HERE THOUGH...WITH LADYSMITH...HAYWARD...AND BLACK RIVER FALLS ALREADY 1/2 MILE OR LESS WITHIN THE STRATUS DECK...IT IS PROBABLY SAFE TO ASSUME THAT DENSE FOG WILL IMPACT WRN WI. 4. FOR THE ST. CROIX VALLEY...TWIN CITIES...AND DOWN TOWARD MKT AND SOUTH CENTRAL MN...THINGS LOOK A BIT MORE FAVORABLE FOR FOG. HERE...THE STRATUS HAS CLEARED OUT AND THE DRY AIR HAS NOT MADE MUCH OF A PUSH AND STILL CONFIDENT DENSE FOG WILL BE PREVALENT ONCE THE HIGH CLOUDS CLEAR OUT IN THE NEXT COUPLE OF HOURS...ESPECIALLY CONSIDERING ACQ...FBL...AND SYN ARE ALREADY OBSERVING FOG. THE ONLY QUESTION BECOMES HOW FAR EAST DOES THE DRY AIR MAKE IT /HAVE ALREADY SEEN MKT GO FROM 1/2 TO 3 MILES VSBY/. AT ANY RATE...WILL NOT MAKE AN CHANGES TO THE CURRENT FOG ADVISORY...BUT AT THIS POINT IS LOOKING AT THE VERY LEAST THAT FOG MAY BE A BIT QUESTIONABLE OUT IN WEST CENTRAL AND SW MN. MPG && .PREV DISCUSSION... /ISSUED 510 PM CST SAT DEC 1 2012/ SHORT TERM...TONIGHT THROUGH MONDAY NIGHT. A WEAK COLD FRONT...MORE LIKE A WIND SHIFT LINE...IS PUSHING THROUGH MINNESOTA THIS AFTERNOON. CLEARING SKIES IMMEDIATELY BEHIND THE FRONT HAS ALLOWED TEMPERATURES TO WARM TO A GREATER EXTENT THERE THAN AHEAD OF THE FRONT WHERE LOW CLOUDS AND LIGHT FOG PERSIST. TEMPERATURES RANGED FROM THE MID 50S IN THE MN RIVER VALLEY OF SWRN MN TO THE UPPER 30S OR LOWER 40S ACROSS CENTRAL MN AND WRN WI. THERE ARE NO SIGNS OF DRIER BOUNDARY LAYER AIR OFF TO THE WEST AND A SURFACE RIDGE OF HIGH PRESSURE IS EXPECTED TO BUILD OVERHEAD TONIGHT. IDEAL RADIATIONAL COOLING CONDITIONS ARE EXPECTED...ASIDE FROM SOME HIGH CLOUDS CURRENTLY OVER ERN SD WHICH SHOULD PASS OVERHEAD THIS EVENING. WITH CURRENT DEW POINTS SEVERAL DEGREES ABOVE NORMAL HIGH TEMPS...THINK THERE IS A GOOD CHANCE FOR WIDESPREAD DENSE FOG TONIGHT. TEMPERATURES SHOULD DROP BELOW FREEZING AFTER MIDNIGHT OVER JUST ABOUT THE ENTIRE AREA SO SOME FROST OR LIGHT ICING MAY DEVELOP ON UNTREATED ROADWAYS. DECIDED TO POST A FREEZING FOG ADVISORY FOR AREAS THAT STAND THE BEST CHANCE OF DROPPING BELOW FREEZING FOR AT LEAST A FEW HOURS DURING THE OCCURRENCE OF DENSE FOG. FARTHER EAST TOWARD THE EAU CLAIRE AND ALBERT LEA AREAS THERE IS MORE UNCERTAINTY OF SUBFREEZING TEMPS SO POSTED A DENSE FOG ADVISORY THERE. UNCERTAINTY EXISTS WITH THE ONSET OF SUCH FOG...ESPECIALLY EAST. VISIBILITIES HAVE BEEN RUNNING IN THE 1 TO 4 MILE RANGE ACROSS THE EASTERN AREAS ALL DAY. THINK THE CLEARING LINE WILL SLOW ITS PROGRESSION EAST AFTER SUNSET AND CLOUDS MAY HANG IN UNTIL LATE TONIGHT IN THE EAU AREA. THEREFORE...DELAYED THE ADVISORY START TIME UNTIL 09Z. HOWEVER...IF THE CLOUDS CLEAR QUICKER THAN ANTICIPATED WE COULD SEE FOG BECOMING DENSE SEVERAL HOURS EARLIER. THE EVENING SHIFT MAY NEED TO ADJUST THINGS AS TRENDS BECOME ESTABLISHED. THE FOG WILL DISSIPATE QUICKLY SUNDAY MORNING AS RETURN FLOW DEVELOPS IN RESPONSE TO LOW PRESSURE PROPAGATING ACROSS THE NORTHERN ROCKIES AND INTO THE DAKOTAS. THIS WILL KEEP TEMPS QUITE MILD...BUT A WARM FRONT WILL BISECT THE AREA WITH A 20 DEG SPREAD FROM NORTH TO SOUTH. SOME LOCATIONS COULD TOUCH 60 NEAR REDWOOD FALLS AS 925 MB TEMPS RISE TO +12C. THE WARM FRONT WILL LIFT INTO NORTHERN MN SUNDAY NIGHT. LOW PRESSURE WILL TRACK WELL NORTH OF THE AREA AND A TRAILING COLD FRONT WILL PUSH THROUGH MINNESOTA AND WESTERN WI MONDAY. STILL LOOKS LIKE A DRY FRONT FOR THE MOST PART...BUT A FEW SHOWERS ARE STILL POSSIBLE. MAINTAINED LOW CHC POPS FOR NRN AND ERN AREAS. LONG TERM...TUESDAY THROUGH NEXT SATURDAY. A SECOND COLD FRONT WILL SINK SOUTH ON TUESDAY WHICH WILL BRING A RETURN OF THE POLAR AIR. EARLY HIGHS MAY REACH THE 40S AND 50S BEFORE TEMPERATURES DROP INTO THE TEENS AND 20S BY LATE EVENING. THIS FRONT TOO...LOOKS DRY. HIGH PRESSURE WILL BUILD IN TUESDAY NIGHT AND PUSH SOUTHEAST WEDNESDAY. MOISTURE ADVECTION AND SOMEWHAT MILDER AIR WILL TRY TO RETURN WEDNESDAY AND WEDNESDAY NIGHT...BUT A SHALLOW COLD LAYER COULD BRING WINTRY PRECIP CHANCES WEDNESDAY NIGHT AND THURSDAY MORNING. AT THIS POINT IT DOES NOT LOOK LIKE ANYTHING MORE THAN A TRACE TYPE EVENT. ANOTHER COLD FRONT WILL SINK THROUGH FRIDAY WITH COLDER AIR TO FOLLOW INTO THE WEEKEND. && .AVIATION.../06Z TAF ISSUANCE/ SEE UPDATE SECTION ABOVE FOR MANY ISSUES SURROUNDING FG. CURRENT TAFS HAVE A PRETTY GOOD HANDLE ON THINGS AT THE MOMENT. PLENTY OF LOW LEVEL MOISTURE /OUTSIDE OF SW MN/ AND LIGHT WINDS WILL RESULT IN EXPANSION OF STRATUS AND FG AS MID CLOUDS ASSOCIATED WITH POTENT SHORTWAVE NEAR MSP QUICKLY MOVE EAST. LOW CLOUDS WILL LINGER INTO THE MORNING...BUT INCREASING SRLY WINDS AND INFLUX OF DRIER AIR SHOULD LEAD TO RAPID IMPROVEMENTS IN CONDITIONS BETWEEN 14Z AND 15Z FOR MN AND POSSIBLY AS LATE AT 17Z OVER IN WI WHERE WINDS WILL REMAIN CALM. ONCE THE FOG BURNS OFF...IT WILL BE VFR CONDS WITH INCREASING S/SE WINDS AS A DEEP AREA BEGINS MOVING ACROSS SRN CAN...WITH A STRONG COLD FRONT APPROACHING WRN MN BY 12Z MON. MAIN QUESTIONS FOR TAFS TONIGHT LIES WITH AXN AND RWF. FOR AXN...STRATUS/FG DECK IS ABOUT TO MOVE IN WITH CONDITIONS VARYING FROM 200 FEET AND 1/4SM TO 1K FT AND 3SM. FOR NOW...PLAYED THE IFR CIG/VIS ROUTE...BUT IT COULD EASILY BE 1/4SM AND 200 FT LIKE FFM CURRENTLY HAS. AT RWF...DRIER HAS FOUND ITS WAY THERE AND VIS FORECASTS FROM BOTH THE GFSLAMP AND HRRR KEEP THE FOG TO THE NORTH AND EAST...SO WENT OPTIMISTIC THERE. KMSP...MID CLOUDS BEGINNING TO CLEAR THE AREA AND AS THEY MOVE EAST...FOG FORMATION SHOULD BEGIN QUICKLY OUTSIDE OF THE URBAN HEAT ISLAND. BIG QUESTION FOR FOG THOUGH IS WINDS. 1-MINUTE WIND DATA HAS SHOWN FAIRLY PERSISTENT W-NW WINDS AROUND 5 KTS AND IF THIS CONTINUES TO BE THE CASE...DENSE FOG WILL BE UNLIKELY AT THE FIELD AS THINGS DRAIN INTO THE MN VALLEY. CONTINUED WITH THE TEMPO GROUP...THOUGH LOWERED THE VIS TO 1/2SM. WITH TEMP/DEWP DEPRESSION AT 0 DEGS AT 06Z...COULD SEE THAT TEMPO NEEDING TO BE THE PREVAILING GROUP. AFTER THE MORNING FG/STRATUS CLEARS OUT...REST OF THE TAF IS PRETTY STRAIGHT FORWARD. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE. CHANCE OF -RA. WIND S AT 10 KTS BECOMING WNW AT 15-20 KTS WITH LATE AFTERNOON FRONTAL PASSAGE. TUE...VFR. WIND NW AT 10-15 KTS. WED...VFR. WIND SE AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FREEZING FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR ANOKA-BENTON- BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS- FARIBAULT-HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE- LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET- POPE-RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY- STEARNS-STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WATONWAN- WRIGHT-YELLOW MEDICINE. DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR FREEBORN-GOODHUE- STEELE. WI...FREEZING FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR BARRON-POLK-RUSK- ST. CROIX. DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE. && $$ BORGHOFF/MPG
AREA FORECAST DISCUSSION
NWS BILLINGS MT
316 PM MST SUN DEC 2 2012 .SHORT TERM...VALID FOR MON AND TUE... LATEST REPORTS FROM GAP FLOW AREAS...LARGE TREES DOWN IN LIVINGSTON WITH GUSTS OVER 70 MPH COMMON. RECENT GUSTS TO 73 MPH AT THE STILLWATER MINE. WINDS WILL SHIFT TO THE WEST LATE TODAY/EARLY THIS EVENING WITH THE FRONTAL PASSAGE AND SHOULD EFFECTIVELY DIMINISH THE THREAT OF HIGH WINDS...THOUGH THEY WILL REMAIN BRISK AND GUSTY OUT OF THE WEST. AS A MATTER OF FACT...WE MAY NEED A WIND ADVISORY FOR MONDAY OR MONDAY NIGHT INTO TUESDAY IN THE GAP FLOW AREAS AS A FAVORABLE PRESSURE GRADIENT QUICKLY REBOUNDS AND SETS UP AGAIN WITH LEE SIDE TROUGHING AND ZONAL FLOW ALOFT. WILL NOT MUDDY THE WATERS BY ISSUING THIS NOW...BUT HAVE BUMPED UP WINDS MONDAY THROUGH TUESDAY AT LIVINGSTON AND THE FOOTHILLS. MOUNTAIN WAVE CONCERNS...CROSS SECTIONS OVER THE RED LODGE FOOTHILLS FROM THIS MORNINGS MODEL CYCLE CONTINUE TO INDICATE MODERATE OR LITTLE DOWNWARD MOMENTUM SHIFT. SO SIGNIFICANT MOUNTAIN WAVE ACTIVITY THERE IS NOT EXPECTED...HOWEVER GUSTS TO 58 MPH HAVE BEEN OBSERVED AS LOW AS TIPI VILLAGE NEAR 6000 FT...AND THIS MAY CONTINUE INTO THE EARLY EVENING. SHERIDAN IS MY MAIN CONCERN THIS EVENING. GFS AND RAP SOUNDINGS SHOW OVER 60 KTS JUST BELOW 2500 FT AGL WITH A DISTINCT CRITICAL LAYER. STRONG NORTHWESTERLY SWITCH WITH THE FRONTAL PASSAGE AROUND 9-10 PM WITH IMPRESSIVE POST FRONTAL PRESSURE RISES MOVING NW TO SE. THE ONLY THING AGAINST SOME TYPE OF HIGH WIND IS THE SW TO NE ORIENTATION OF THE JET. HOWEVER...FEEL THERE IS A SIGNIFICANT THREAT AS THESE TYPE OF EVENTS AND PROFILES ARE GENERALLY RARE. CONFIDENCE HIGH FOR FOOTHILLS ABOVE SHERIDAN...LOWER FOR ACTUALLY OCCURRING IN SHERIDAN. WILL ISSUE A HIGH WIND WARNING THROUGH 07Z FOR SHERIDAN FOOTHILLS. WILL DISCUSS THIS BEING A BRIEF 2 HOUR EVENT AT SOME POINT THIS EVENING. CLOUD COVER MAY BE RESPONSIBLE FOR LIMITING AND MODIFYING THE VERTICAL ATMOSPHERE PROFILES WE EXPECTED TODAY AS STRONG WINDS HAVE NOT YET OCCURRED AT BIG TIMBER NOR UP TO JUDITH GAP. HOWEVER ...THERE IS STILL A DECENT POTENTIAL FOR STRONG WINDS TO DEVELOP IN THIS AREA THROUGH EVENING FROM BIG TIMBER TO HARLOWTON AND JUDITH GAP. WE HAVE A DYNAMIC AND PROGRESSIVE TROUGH MOVING ACROSS THIS EVENING WITH STRONG SUBSIDENCE BEHIND THE ASSOCIATED COLD FRONT. THEREFORE WILL KEEP HIGHLIGHTS GOING AT JUDITH GAP AND IN SWEET GRASS. WINTER STORM WARNING...ACCORDING TO THE LATEST NORMALIZED WATER VAPOR PROGGS...THE DEEPEST MOISTURE FETCH FROM THE PACIFIC WILL AFFECT THE ABSAROKA/BEARTOOTH MOUNTAINS BETWEEN 18Z AND 00Z THIS EVENING. CROSS SECTIONS INDICATE DECENT LIFT AND OROGRAPHIC FORCING ON THE SOUTH AND WEST FACING SLOPES AT THIS TIME. ANY HEAVY SNOWFALL ACCUMULATIONS WILL LIKELY BE AT OR ABOVE 7500 TO 8000 FEET WHICH IS ABOUT WHERE THE FREEZING LEVEL IS AT THIS AFTERNOON...AND COOKE CITY WEB CAMS AND SPOTTER REPORTS SHOW MELTING SNOW AND LITTLE ACCUMULATION LOWER. WIND GUSTS AT RAWS STATIONS IN THE HIGH COUNTRY ARE COMMONLY SEEING 60 MPH. THEREFORE...THE WINTER STORM WARNING ABOVE 7000 FEET LOOKS OKAY INTO THE EVENING...AND DOES NOT NEED TO BE ADJUSTED. HOWEVER...WE MAY BE ABLE TO CANCEL IT EARLY. BT .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... ONLY MINOR CHANGES TO THE EXTENDED PERIOD...AS MODELS CONTINUE IN GOOD AGREEMENT UNTIL LATE IN THE WEEK....WITH GFS FAVORING MORE AMPLIFIED NORTHWEST FLOW ALOFT LATE IN THE PERIOD. THE BEGINNING OF THE PERIOD CONTINUES TO LOOK SOMEWHAT UNSETTLED. AS FOR TEMPS...A GENERAL COOLING TREND APPEARS TO BE ON TAP FOR EXTENDED PERIOD. WEAK PACIFIC SHORTWAVES ARE PROGGED TO MOVE ACROSS THE REGION WEDNESDAY NIGHT THROUGH EARLY FRIDAY. HAVE CONTINUED WITH INHERITED POPS AT THIS TIME...AS STILL CANNOT PIN POINT TIMING MUCH BETTER. MODELS CONTINUE TO INDICATE DEEPENING UNSETTLED NORTHWEST FLOW THROUGH THE END OF THE PERIOD...BUT GFS INDICATES A STRONG SHORTWAVE TROF DIGGING ACROSS THE NORTHERN ROCKIES...OPENING THE DOOR FOR COLDER AIR TO SLIDE SOUTH OUT OF CANADA. LATEST EC LOOKS LIKE IT BEGINNING TO LEAN TOWARD THE GFS...ALTHOUGH TIMING IS A BIT OFF. CONTINUED WITH COLDER TEMPS...AND CONTINUE PRECIP POTENTIAL TO END THE EXTENDED PERIOD. AAG && .AVIATION... VERY STRONG AND GUSTY SOUTHWEST WINDS WILL CONTINUE FOR AREAS WEST OF KBIL...INCLUDING BIG TIMBER...JUDITH GAP...HARLOWTON...LIVINGSTON...RED LODGE...KLVM...AND THE PARADISE VALLEY. GUSTS AS HIGH AS 65 KNOTS HAVE BEEN REPORTED IN AND AROUND KLVM...INCLUDING IN THE PARADISE VALLEY. GUSTS OF 35 TO 50 KNOTS ARE EXPECTED FROM BIG TIMBER NORTH TO JUDITH GAP. WINDS ARE EXPECTED TO PERSIST THROUGH THIS EVENING. WINDS ARE EXPECTED TO TURN WESTERLY LATE THIS EVENING...BUT REMAIN GUSTY OVERNIGHT...ESPECIALLY WEST OF KBIL. A PERIOD OF VERY STRONG AND GUSTY WINDS IS EXPECTED TO IMPACT SHERIDAN AND THE BIGHORN FOOTHILLS THIS EVENING...WITH GUSTS AROUND 60 KNOTS IN THE FOOTHILLS...AND 50 KNOTS POSSIBLE INTO SHERIDAN. LOW LEVEL TURBULENCE IS POSSIBLE ACROSS EASTERN ROUTES...FROM KBIL EAST...AS WIND SPEED INCREASES RAPIDLY JUST ABOVE THE SURFACE. VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS THE AREA...WITH THE EXCEPTION OF SNOW OVER THE BEARTOOTH/ABSAROKA MOUNTAINS...WHERE SNOW AND WIND WILL COMBINE TO REDUCE VISIBILITIES. AAG && .PRELIMINARY POINT TEMP/POPS... MON TUE WED THU FRI SAT SUN ----------------------------------------------------------- BIL 038/053 030/049 038/053 032/041 025/041 027/037 022/026 20/N 00/B 01/B 32/W 32/W 11/B 33/J LVM 038/046 032/047 038/053 030/041 019/040 026/032 020/026 41/N 11/N 12/W 32/W 22/J 12/W 22/J HDN 034/055 026/049 030/054 029/042 025/040 022/037 023/028 30/N 00/U 01/B 32/W 32/W 12/W 33/J MLS 036/052 024/048 029/052 029/039 019/036 021/035 018/027 20/N 00/B 01/B 32/W 22/J 12/J 33/J 4BQ 036/053 024/050 029/055 030/042 021/037 021/036 021/027 30/N 00/U 01/B 32/W 32/J 02/J 33/J BHK 035/048 023/046 027/049 025/035 016/032 021/031 018/025 30/N 00/U 00/B 22/J 22/J 02/J 33/J SHR 030/045 022/046 028/050 025/037 020/034 017/031 017/022 20/B 00/U 01/B 33/J 33/J 12/J 33/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WIND ADVISORY IN EFFECT UNTIL 10 PM MST THIS EVENING FOR ZONE 41. HIGH WIND WARNING IN EFFECT UNTIL 10 PM MST THIS EVENING FOR ZONES 63>66. WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST MONDAY ABOVE 7000 FEET FOR ZONE 67. WY...HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MST TONIGHT FOR ZONE 99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1014 AM MST SUN DEC 2 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY... UPDATED THE FORECAST TO SPREAD POPS FARTHER EAST AND SOUTH THIS MORNING AND AFTERNOON. FROM WHAT THE CURRENT RADAR TREND AND WHAT THE LATEST HRRR MODEL OUTPUT WAS SHOW...THE RAIN IS LIKELY TO BE A LITTLE MORE WIDESPREAD THEN WHAT THE LATEST 12Z NAM/GFS WERE SHOWING FOR THIS AFTERNOON. THE REST OF THE SHORT TERM FORECAST AND HIGH WIND HIGHLIGHTS LOOK GOOD. RSMITH PREVIOUS DISCUSSION...WITH A GLANCE AT WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD...THE LATE WEEKEND STORM SYSTEM SEEMS TO HAVE BEGUN ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES REGION. THE UPPER LEVEL TROUGH IS DEEPENING AND NARROWING JUST NW OF THE PUGET SOUND. A SIGNIFICANT PLUME OF PACIFIC MOISTURE HAS NOW SPREAD FROM NORTHERN CALIFORNIA TO SEATTLE AND FROM SOUTHERN IDAHO TO WESTERN MONTANA. FORECAST CHALLENGES INCLUDE FREEZING FOG THIS MORNING...PRECIP TIMING...AMOUNT...AND TYPE FROM TODAY THROUGH EARLY MONDAY MORNING AND AREAS OF VERY STRONG WINDS FROM TONIGHT THROUGH MONDAY NIGHT. PERSISTENT FREEZING FOG HAS INTERMITTENTLY EXPANDED AND CONTRACTED OVER THE MID TO LOWER RIVER VALLEYS THROUGHOUT THE OVERNIGHT HOURS. WITH SUCH A STRONG INVERSION AT THE SURFACE...WOULD EXPECT THE FOG TO HOLD ON UNTIL WARMER TEMPERATURES FROM THE SOUTH HELP TO DISSIPATE THE FOG LATER TODAY. HEADLINE FOR A DENSE FOG ADVISORY HAS IT WELL IN HAND. WOULD EXPECT THE FOG TO BE LIMITED TO AREAS JUST ALONG AND VERY NEAR THE RIVER VALLEYS AND OTHER DRAINAGES. INITIALLY...THE FORECAST IS A LITTLE TRICKY BUT THE CURRENT THINKING IS THAT DURING THE MORNING HOURS TODAY...THE STRONG SURFACE INVERSION REMAINS IN PLACE AS PRECIPITATION BEGINS TO EMERGE ACROSS CENTRAL MONTANA AND SNEAK INTO OUR WESTERN AND NORTHWESTERN ZONES. MID LEVEL AND JUST ABOVE THE INVERSION TEMPERATURES ARE WARM ENOUGH FOR RAIN...BUT THE NARROW LAYER OF COLDER MORNING TEMPERATURES MAY IN FACT REFREEZE THAT RAIN JUST AS IT REACHES THE SURFACE. THIS AFTERNOON...TEMPERATURES WILL WARM ENOUGH TO CHANGE ALL PRECIP TO RAIN AS THE FOG DISSIPATES...AT LEAST TEMPORARILY. THROUGH THE AFTERNOON AND EARLY EVENING HOURS...THE FORCING FOR ASCENT AND AREAS OF RAIN TRANSITION MORE TOWARD OUR NORTHERN ZONES AS STRONG SUBSIDENCE TAKES OVER WITH A SHIFT IN WINDS FROM THE WEST. TONIGHT...STRONGER WESTERLY WINDS WILL SPILL INTO EASTERN MONTANA. MOST LOCATIONS ACROSS OUR WESTERN...CENTRAL AND SOUTHERN ZONES WILL EASILY EXPERIENCE STRONG GUSTY WINDS IN THE 35G45 KT RANGE...BUT WOULD LIKELY NOT QUITE REACH HIGH WIND CRITERIA. THE TYPICALLY SUSCEPTIBLE AREAS FOR HIGH WINDS IN SUCH SITUATIONS...SUCH AS SW PHILLIPS COUNTY HAS RECENTLY HAD CONSISTENT MODEL SUPPORT FOR EVEN HIGHER WINDS AND HAS BEEN UPGRADED TO A HIGH WIND WARNING. THE SLOPES OF THE LITTLE ROCKIES AND THE STRETCH OF US HIGHWAY 191 SOUTH OF MALTA WILL LIKELY EXPERIENCE WIND GUSTS IN EXCESS OF 60 MPH. DO NOT SEE ENOUGH SHORT TERM MODEL SUPPORT OR CONSISTENCY TO INCLUDE ANY OTHER ZONES IN THE WARNING DOWNSTREAM AT THIS TIME. THIS COLD FRONT WILL BRING A NOTICEABLE DROP IN TEMPERATURES FOR NE MONTANA BUT NOT NEAR AS DRASTIC OF A DROP AS JUST OVER THE CANADIAN BORDER. THE WORST OF IT QUICKLY PASSES ALONG TO OUR NORTHEAST. MONDAY THROUGH MONDAY NIGHT...PRECIP PUSHES WELL AWAY FROM NORTHEAST MONTANA AS NORTHWESTERLY UPPER LEVEL FLOW GRADUALLY TRANSITIONS TO A WEAK RIDGE BY TUESDAY. TEMPERATURES TOWARD THE END OF THIS FORECAST PERIOD WILL REMAIN ON THE COOL SIDE BUT NOT SIGNIFICANTLY COLD AS THE CANADIAN ARCTIC INFLUENCE IS BUFFETED SOMEWHAT BY HIGHER PRESSURES FROM THE SOUTH. BMICKELSON .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... UPPER RIDGE WILL TO THE EAST TUESDAY NIGHT AND WEDNESDAY. UPPER TROUGH WILL MOVE ACROSS THE CANADIAN PRAIRIES AND MONTANA WEDNESDAY AND WEDNESDAY NIGHT WHICH WILL BRING A COLD FRONT THROUGH THE FORECAST AREA WEDNESDAY AFTERNOON AND EVENING. LIMITED MOISTURE WITH THIS SYSTEM BUT A FEW RAIN SHOWERS REMAINS POSSIBLE ON WEDNESDAY SWITCHING TO SNOW SHOWERS WEDNESDAY NIGHT AS TEMPERATURES FALL. WILL MENTION A SLIGHT CHANCE FOR NOW. NORTHWEST FLOW ALOFT WILL PREVAIL FROM THURSDAY INTO THE WEEKEND WITH COLDER AIR MASS IN PLACE. COULD SEE A SNOW SHOWER ON THURSDAY WITH A SHORTWAVE IN THE NORTHWEST FLOW ALOFT. CANADIAN HIGH PRESSURE WILL KEEP WEATHER DRY THURSDAY NIGHT AND FRIDAY. THE MODEL DIFFERENCES START APPEARING TOWARDS THE WEEKEND WITH ECMWF MAINTAINING NORTHWEST FLOW ALOFT WITH SHORTWAVES WHILE GFS WANTS TO DIG AN UPPER TROUGH OVER MONTANA. EITHER WAY...THERE IS SOME POTENTIAL FOR SNOW WITH THE GFS ADVERTISING A BETTER CHANCE THAN THE ECMWF. WILL MENTION EITHER A CHANCE OR SLIGHT CHANCE OF SNOW FOR NOW. FORRESTER && .AVIATION... SOME PATCHY FOG REMAINS IN THE MISSOURI RIVER VALLEY THIS MORNING...KEEPING VISIBILITY MVFR AT KOLF THROUGH LATE MORNING. OTHERWISE SOUTHERLY WINDS AROUND 10 KNOTS WILL DEVELOP AND DRIER AIR ALOFT WILL MIX DOWN TO THE SURFACE BY EARLY AFTERNOON...KEEPING CONDITIONS VFR. A MIX OF MID AND HIGH CLOUDS CAN BE EXPECTED MOST OF TODAY AND TONIGHT. A COLD FRONT IN THE LATE AFTERNOON OR EARLY EVENING WILL BRING A CHANCE OF RAIN ESPECIALLY TO KGGW AND KOLF THAT MAY TURN TO SNOW DURING THE EVENING. WEST WINDS 15 TO 25 KNOTS WITH HIGHER GUSTS WILL DEVELOP THIS EVENING AND CONTINUE OVERNIGHT AND INTO MONDAY. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 2 PM THIS AFTERNOON TO 11 PM MST MONDAY FOR SOUTHWEST PHILLIPS. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
357 AM MST SUN DEC 2 2012 .SHORT TERM...VALID FOR TDY AND MON... SIGNIFICANT SURFACE PRESSURE FALLS ARE BEING OBSERVED ALREADY THIS MORNING ACROSS THE NORTHERN ROCKIES...WHICH IS A HARBINGER OF HIGH WINDS THAT WILL OCCUR TODAY AND THIS EVENING ACROSS PARTS OF SOUTH CENTRAL MT. THERE IS STILL SOME UNCERTAINTY IN THE DETAILS OF THIS WIND EVENT AS A RELATIVELY DEEP SURFACE LOW SCOOTS ACROSS NORTHERN MT...BUT WE ARE VERY CONFIDENT THAT AT LEAST THE LIVINGSTON TO NYE AND BIG TIMER AREAS WILL HAVE VERY STRONG WINDS. TODAY...LOW- AND MID-LEVEL SOUTHWEST FLOW RAMPS UP QUICKLY...WHICH YIELDS 700-HPA WINDS ON THE ORDER OF 70 TO 80 KT AROUND LIVINGSTON DURING THE MORNING. FORECAST SOUNDINGS STILL CALL FOR A RELATIVELY STABLE LAYER NEAR THE MOUNTAIN-TOP LAYER...AND SINCE GAP WINDS ARE ALREADY INCREASING AS OF 10 UTC...THAT IDEA IS LIKELY CORRECT. THE SCENARIO SHOULD EASILY YIELD SUSTAINED WINDS NEAR 50 MPH AND GUSTS PERHAPS CLOSE TO 80 MPH AROUND LIVINGSTON...ESPECIALLY DURING LATE MORNING WHEN 5 HPA/3 HOUR SURFACE PRESSURE FALLS ARE CENTERED OVER NORTHERN ID. BY 18 UTC...THE BOUNDARY LAYER WILL BECOME WELL-MIXED AND CAUSE WINDS EVEN OUTSIDE OF THE GAP AREAS TO GET STRONG...WITH BIG TIMBER THEN LIKELY TO TAP INTO 50 KT FLOW ABOVE THE GROUND. WE DID...HOWEVER...DECIDE TO CANCEL THE HIGH WIND WATCH FOR HARLOWTON AND RYEGATE BECAUSE THE 00 UTC NAM AND RECENT RAP AND HRRR RUNS DO NOT REVEAL QUITE ENOUGH PRE-FRONTAL LOW-LEVEL WIND FOR A WARNING. NOTE THAT THE 00 UTC GFS...WHICH IS A BIT OF AN OUTLIER...SHOWS 60 KT 500 M AGL WINDS IN THOSE AREAS IN THE LATE AFTERNOON THOUGH. WE DID DECIDE TO GO WITH A HIGH WIND WARNING FOR JUDITH GAP...BANKING ON TERRAIN ENHANCEMENT OF SOUTHERLY FLOW IN THAT AREA TO PUSH WIND SPEEDS UP AS THE PRESSURE FALLS PASS NORTH OF THE AREA. WE WILL BE KEEPING A CLOSE EYE ON THE PARADISE VALLEY FOR THAT TOO...BUT MOST HIGH-RESOLUTION GUIDANCE SUGGESTED SPEEDS JUST SHORT OF WHAT WOULD BE NEEDED FOR A WARNING THERE. ADMITTEDLY...WE DO NOT HAVE MUCH IN THE WAY OF ANALOGS FOR HIGH WINDS IN THE PARADISE VALLEY...AND OUR CONFIDENCE IN THAT DECISION IS THUS LOW. IN THE MOUNTAINS...THE WINTER STORM WARNING REMAINS IN PLACE...AND IT STILL LOOKS LIKE THE MAIN IMPACT WILL BE FROM VERY STRONG WINDS IN COMBINATION WITH SNOW /WHICH ITSELF WOULD NOT BE ENOUGH FOR THE WARNING/. MOUNTAIN-TOP WINDS FROM THE HIGHER-RESOLUTION MODELS ARE STILL ON THE ORDER OF 80 KT. GUIDANCE STILL DID NOT SHOW ENOUGH OF A WELL-DEFINED CRITICAL LAYER OF SPEED SHEAR TO MAKE US ANTICIPATE MOUNTAIN-WAVE-INDUCED HIGH WINDS AT RED LODGE...BUT THE 00 UTC NAM DID ACTUALLY SUGGEST A BIT MORE MOMENTUM TRANSFER DOWN THE SLOPES. THUS...WE WILL NEED TO KEEP AN EYE ON THAT DURING THE DAY TODAY. TONIGHT...A SURFACE COLD FRONT WILL CROSS THE AREA...WHICH WILL BE ACCOMPANIED BY 5-7 HPA/3 HOUR SURFACE PRESSURE RISES...MAINLY FROM HARLOWTON AND LIVINGSTON TO BILLINGS AND SHERIDAN. THE ISALLOBARIC COMPONENT OF THE WINDS THUS COULD BE SIGNIFICANT...WHICH DOES MAKE US CONCERNED THAT WE COULD END UP WITH HIGH POST-FRONTAL WINDS FOR A TIME. FORECAST SOUNDINGS...ESPECIALLY FROM THE 00 UTC NAM...EVEN KEEP THE BOUNDARY LAYER WELL-MIXED WITH THE FRONTAL PASSAGE. WINDS IN THE MIXED LAYER PEAK JUST UNDER 50 KT THOUGH...SO THERE WAS NOT ENOUGH CONFIDENCE TO ADD ANY WIND HEADLINES IN AREAS LIKE BILLINGS OR SHERIDAN OVERNIGHT. ACTUALLY...WE WILL HAVE TO KEEP A CLOSE EYE ON SHERIDAN FOR THE POSSIBILITY OF MOUNTAIN WAVE ACTIVITY NEAR THE FRONTAL PASSAGE TOO...THOUGH AGAIN MODEL-DERIVED CROSS SECTIONS DO NOT SHOW A STRONG SIGNATURE FOR MOMENTUM TRANSFER ALL THE WAY DOWN TO THE SURFACE IN THE LEE OF THE BIG HORNS. THERE WERE A FEW HINTS IN THE 00 UTC GUIDANCE OF GREATER MOMENTUM TRANSFER THAN WHAT PAST RUNS SUGGESTED THOUGH. OUTSIDE OF WIND ISSUES...WE DID MAINTAIN 20 TO 30 POPS WITH THE PASSAGE OF THE LOW- AND MID-LEVEL FRONT...WITH SOME CLUSTERING OF MODEL QPF OUTPUT EVEN NOTED AROUND BROADUS. MON...WESTERLY LOW- AND MID-LEVEL FLOW WILL BE IN PLACE...AND THAT DOWNSLOPE SIGNATURE AND EFFICIENT MIXING TO AROUND 700 HPA WILL BE ENOUGH TO PUSH HIGHS ON THE PLAINS OVER 50 F AGAIN. THE SUBSIDENCE ALOFT SHOWN BY 500-300 HPA Q-VECTOR DIVERGENCE SUGGESTS THERE WILL EVEN BE A GOOD AMOUNT OF SUN TO HELP OUT...SO WE ADJUSTED FORECAST HIGHS UPWARD...CLOSE TO THE 00 UTC MAV OUTPUT. THAT MOS OFTEN DOES WELL ON DAYS WITH DOWNSLOPE-AIDED WARMING DURING THE WINTER ON THE HIGH PLAINS AND FRONT RANGE WHEN THERE IS SUNSHINE. THE 00 UTC GFS AND NAM BOTH CALL FOR MIXED-LAYER WINDS OF 30 T0 35 KT...WITH PEAK SPEEDS AT ITS TOP NEAR 45 KT...SO IT WILL DEFINITELY BE WINDY. THE LACK OF NOTABLE COLD AIR ADVECTION SUGGESTS HEADLINE-WORTHY SPEEDS ARE UNLIKELY OVER THE PLAINS OF SOUTH CENTRAL AND SOUTHEASTERN MT. HOWEVER...THE 00 UTC MET AND MAV MOS BOTH SUGGEST WE COULD NEED AN ADVISORY AROUND LIVINGSTON AGAIN. SCHULTZ .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... MEDIUM RANGE GUIDANCE IN RELATIVELY GOOD AGREEMENT THROUGH MUCH OF THE PERIOD UNTIL MODELS DIVERGE A BIT LATE IN THE WEEK AND INTO THE WEEKEND. THE GFS BEGINNING TO ADVERTISE A VIGOROUS SHORTWAVE TROUGH DIGGING ACROSS THE NORTHERN ROCKIES...DEEPENING THE TROUGH AND OPENING THE DOOR FOR COLDER AIR TO SLIDE SOUTH OUT OF CANADA. LATEST ECMWF SEEMS TO BE FALLING IN LINE WITH THIS SOLUTIONS BUT THE TIMING BETWEEN THE TWO IS OUT OF PHASE. SEEMS LIKE THE BEST THAT CAN BE SAID AT THIS POINT IS MODELS ARE SUGGESTIVE OF MORE AMPLIFIED NORTHWEST FLOW ALOFT BY LATE WEEK AND INTO NEXT WEEKEND WHICH IS SUPPORTIVE OF COOLER TEMPERATURE AT OR BELOW SEASONAL NORMALS. THIS ALSO INCREASE THE THREAT FOR AT LEAST THE POSSIBILITY OF SOME LIGHT SNOW AS LOW-LEVEL BAROCLINIC ZONE WOULD BE DRAPED ACROSS THE AREA. EARLIER IN THE PERIOD...WEAK PACIFIC SHORTWAVES ARE SLATED TO MOVE ACROSS THE AREA WEDNESDAY NIGHT THROUGH EARLY FRIDAY. HAVE INDICATED BETTER THREAT FOR AT LEAST SOME SHOWERS ACROSS THE AREA DURING THIS TIME. AT THIS POINT...COULD NOT ISOLATE A PARTICULAR 12 HOUR PERIOD..BUT INSTEAD BROADBRUSHED THE 36 HOUR PERIOD AS THE BEST THREAT FOR SOME PRECIPITATION. INCREASED THREAT FOR PRECIPITATION AGAIN ON SATURDAY AND INTO SUNDAY TO INDICATE POSSIBILITY OF COLD FRONT SLIPPING SOUTHWARD FROM CANADA BRINGING POSSIBILITY OF SOME LIGHT SNOW. THE WEEKEND PERIOD WILL NEED TO BE WATCHED CLOSELY TO SEE HOW THIS EVOLVES. MEIER && .AVIATION... MAIN AVIATION HAZARD TODAY AND TONIGHT WILL BE WINDS. OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS THE AREA...WITH THE EXCEPTION OF OVER THE BEARTOOTH AND ABSAROKA MOUNTAINS WHERE SNOW AND WIND WILL COMBINE TO REDUCE VISIBILITIES. ALREADY GUSTY SOUTHWEST WINDS WILL INCREASE THIS MORNING FROM LIVINGSTON AND ALONG THE FOOTHILLS OF THE BEARTOOTH MOUNTAINS. EXPECT WINDS TO GUST AS HIGH AS 65 KNOTS IN THE VICINITY OF LIVINGSTON...WITH GUSTS 35 TO 50 KNOTS FROM BIG TIMBER NORTH TO JUDITH GAP. WINDS ARE EXPECTED TO PERSIST INTO THE SUNDAY EVENING...BEFORE SWITCHING TO WESTERLY AND REMAINING FAIRLY GUSTY SUNDAY NIGHT...ESPECIALLY THOSE AREAS WEST OF BILLINGS. MEIER && .PRELIMINARY POINT TEMP/POPS... TDY MON TUE WED THU FRI SAT ------------------------------------------------------- BIL 059 038/054 031/049 035/053 032/041 025/041 027/037 0/N 20/N 00/B 01/B 32/W 32/W 11/B LVM 057 038/047 032/047 033/053 030/041 019/040 026/032 3/W 41/N 11/N 12/W 32/W 22/J 12/W HDN 058 034/057 026/048 030/054 029/042 025/040 022/037 0/N 20/N 00/U 01/B 32/W 32/W 12/W MLS 059 036/053 025/047 029/052 029/039 019/036 021/035 0/B 30/N 00/U 01/B 32/W 22/J 12/J 4BQ 061 036/055 026/049 030/055 030/042 021/037 021/036 0/N 30/N 00/U 01/B 32/W 32/J 02/J BHK 059 035/049 024/045 028/049 025/035 016/032 021/031 0/B 30/N 00/U 00/B 22/J 22/J 02/J SHR 060 030/048 022/045 028/050 025/037 020/034 017/031 0/N 20/N 00/U 01/B 33/J 33/J 12/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WIND ADVISORY IN EFFECT FROM 9 AM THIS MORNING TO 10 PM MST THIS EVENING FOR ZONE 41. HIGH WIND WARNING IN EFFECT FROM 9 AM THIS MORNING TO 10 PM MST THIS EVENING FOR ZONE 63. HIGH WIND WARNING IN EFFECT UNTIL 10 PM MST THIS EVENING FOR ZONES 65-66. WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST MONDAY ABOVE 7000 FEET FOR ZONE 67. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
958 PM EST MON DEC 3 2012 .SYNOPSIS... MILD TEMPERATURES WILL CONTINUE AHEAD OF A COLD FRONT...EXPECTED TO CROSS THE EASTERN CAROLINAS ON WEDNESDAY. SCATTERED SHOWERS WILL ACCOMPANY THE FRONT. COOLER CONDITIONS ARE EXPECTED AS HIGH PRESSURE BUILDS OVER THE REGION THURSDAY AND FRIDAY...WITH MODERATING TEMPERATURES NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM MONDAY...THE BROAD CENTER OF 1026 MB HIGH PRESSURE IS LOCATED MAYBE A HUNDRED MILES OFFSHORE...BUT A ZONE OF VERY WEAK PRESSURE GRADIENT EXTENDS AS FAR WEST AS GEORGIA. ALTHOUGH SURFACE WINDS ARE VERY LIGHT OR CALM THERE IS A LITTLE BETTER RETURN FLOW ABOVE THE SURFACE IN THE 1000-2000 FT AGL LAYER...ABOUT 10-12 KNOTS. ALTHOUGH NOT AS WIDESPREAD AS LAST NIGHT...SATELLITE IMAGERY REVEALS AN AREA OF ALTOCUMULUS ALONG THE SOUTH CAROLINA COAST WITH BASES IN THE 7000-8000 FT RANGE. THIS CLOUD COVER APPEARS TO BE RELATED TO MOISTURE TRAPPED UNDERNEATH THE SUBSIDENCE INVERSION ALOFT AND SOME WEAK LIFT ALONG THE UPWARD-SLOPING 295K TO 300K ISENTROPIC SURFACES. WHILE I WOULD LIKE TO SAY THESE CLOUDS WILL NOT BE WITH US MUCH LONGER...NAM AND RUC MODELS SHOW CONTINUED MOISTURE AND WEAK LIFT WHICH MAY SUPPORT SOME CLOUDS ALONG THE COAST THROUGH DAYBREAK. THE AMOUNT OF CLOUD COVER IS CRITICALLY IMPORTANT TONIGHT SINCE BOUNDARY LAYER MOISTURE IS VERY RICH BY DECEMBER STANDARDS...AND JUST A FEW HOURS OF CLEAR SKIES AND CALM WINDS SHOULD YIELD WIDESPREAD FOG. MUCH LIKE WE SAW LAST NIGHT THE FOG COULD BECOME DENSE WITH VISIBILITIES DROPPING BELOW 1/4 MILE AT TIMES. GIVEN UNCERTAINTIES IN THE TIMING AND LOCATION OF ANY DENSE FOG WE WILL NOT ISSUE A DENSE FOG ADVISORY AT THIS TIME...BUT ONE MAY BE NEEDED IN THE NEXT 4-6 HOURS. VERY LITTLE CHANGES ARE NEEDED TO THE REMAINDER OF THE FORECAST...WITH LOWS STILL EXPECTED TO FALL INTO THE UPPER 40S TO AROUND 50. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...HIGH PRESSURE ON TUESDAY WILL GIVE WAY TO A QUICK MOVING FRONT ON WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. THE BEST DYNAMICS WILL REMAIN NORTH OF VIRGINIA AND ISENTROPIC FLOW SHOWS SOME UPWARD VERTICAL MOTION BUT IT IS NOT THAT IMPRESSIVE IN THE LAYER`S AT BELOW 300 KELVIN. SO EXPECT SCATTERED SHOWERS WITH LOW QPF VALUES. MAXIMUM TEMPERATURES ARE EXPECTED TO REMAIN IN THE LOWER TO MID 70S FOR TUESDAY AND UPPER 60S ON WEDNESDAY. LOW TEMPERATURES ARE EXPECTED TO BE IN THE MID 50S TUESDAY AND WITH THE COLD AIR ADVECTION BEHIND THE FRONT TEMPERATURES SHOULD DROP INTO THE LOWER TO MID 40S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...MEDIUM RANGE GUIDANCE CONTINUES TO TREND TOWARD A MILDER AND DRIER SCENARIO FOR THE EXTENDED. INITIALLY A ZONAL FLOW ALOFT PREVAILS THEN A POTENT SHORTWAVE DIVES INTO THE EASTERN SLOPES OF THE ROCKIES ALLOWING A SIGNIFICANT RIDGE TO DEVELOP OFF OF THE SOUTHEAST COAST. CONTINUED TO TREND POPS DOWN THROUGH THE PERIOD FOLLOWING HPC AS BERMUDA HIGH PRESSURE WILL BE THE DOMINANT FEATURE FOR OUR AREA. SLIGHT CHANCE POPS REMAIN FOR MONDAY FOR GENERAL CONVECTION OF ALL THINGS AS SOUNDINGS ARE SHOWING CAPE VALUES NEAR 500 J/KG. TOUGH TO FIND FORCING OTHER THAN MESOSCALE FEATURES SUCH AS THE SEA BREEZE AND DIFFERENTIAL HEATING. SEA FOG REMAINS A POSSIBILITY WITH A QUICK CHECK OF SURFACE DEWPOINTS IN THE MID TO UPPER 60S SUNDAY...AND RELATIVELY LIGHT WINDS. TEMPERATURES WILL BE A BIG STORY AS WELL AS POPS ARE OUT OF THE FORECAST AND WITH 850MB TEMPERATURES SLIGHTLY WARMER THAN WE HAVE CURRENTLY...A COUPLE OF DAYS IN THE 70S APPEARS TO BE A GOOD BET. THESE WILL OCCUR SUNDAY AND MONDAY. LEADING UP TO THIS...MORE SEASONAL VALUES CAN BE EXPECTED. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 00Z...EXPECT MVFR/IFR DUE TO FOG LATE OVERNIGHT INTO TUESDAY MORNING. OTHERWISE EXPECT VFR. NEARLY CLEAR SKIES AND LIGHT WINDS ARE ALLOWING FOR AN IDEAL RADIATIONAL COOLING SET UP FOR OVERNIGHT. LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS DEPICT THAT SUFFICIENT LOW LEVEL MOISTURE IS SPREAD ACROSS MOST OF THE AREA DUE TO CONTINUED ONSHORE FLOW. WITH THE ANTICIPATION OF CALM WINDS...EXPECT MVFR DUE TO REDUCED VISIBILITIES...POSSIBLY JUST BEFORE MIDNIGHT. ANTICIPATE CONDITIONS TO DETERIORATE LOWER TO IFR AND IN SOME AREAS LIFR DUE TO FOG...WITH THE POTENTIAL FOR LOWERED CIGS AROUND 200FT. RESTRICTIONS WILL LIKELY PERSIST AFTER DAYBREAK...WITH CONDITIONS IMPROVING TO VFR BY LATE MORNING AND LASTING THROUGH THE REMAINDER OF THE VALID PERIOD. EXPECT SOUTHWEST WINDS...BECOMING SOUTH-SOUTHWEST WITH SUSTAINED WINDS AOB 8 KTS BY THE AFTERNOON HOURS. EXTENDED OUTLOOK...A SLIGHT CHANCE OF SHOWERS OVERNIGHT TUESDAY INTO WEDNESDAY ASSOCIATED WITH A COLD FRONT. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM MONDAY...NO FURTHER CHANGES ARE NEEDED TO WINDS OR SEAS. PREVIOUS DISCUSSION FROM 630 AM FOLLOWS... LIGHT SOUTH THROUGH WEST WINDS WILL CONTINUE THROUGH THE NIGHT AS HIGH PRESSURE REMAINS JUST OFFSHORE. SEAS CONSIST ALMOST EXCLUSIVELY OF A 9 SECOND SOUTHEAST SWELL...AVERAGING 2-3 FT. THE ONLY CHANGE TO THE FORECAST IS TO RAISE AIR TEMPERATURE FORECASTS BY UP TO 5 DEGREES ACROSS THE OUTER PORTION OF THE COASTAL WATERS WITH THE MILD SUBTROPICAL AIRMASS. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... DESPITE WINDS BEING LESS THAN 10KT TODAY AND EVEN HAVING SOME VARIABILITY IN DIRECTION THERE IS JUST ENOUGH SWELL ENERGY FOR A 3 FT WAVE OUT AT 41013 AND 41036. WNA AND SWAN SHOW THAT FOR THE MOST PART THE 3 FT SEAS WILL LARGELY REMAIN OUTSIDE OF THE 20NM FORECAST ZONES SAVE FOR ALONG FRYING PAN SHOALS..AND EVEN THAT MIGHT BE A STRETCH. WILL ADVERTISE 2 FT FOR ALL BUT AMZ252 WHERE 2 TO 3 FT WILL STILL BE ADVERTISED. EVE SHIFT MAY BE ABLE TO DROP 3 FT SEAS AFTER MONITORING BUOY DATA. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...WINDS WILL BE LIGHT AT 12 UTC ON TUESDAY AND AS HIGH PRESSURE GIVES AWAY TO FRONTAL BOUNDARY THE WIND DIRECTION WILL SWING TO THE SOUTHWEST AND INCREASE UP TO 10 KNOTS BY THE END OF THE DAY. THE WINDS WILL CONTINUE TO VEER FROM THE SOUTHWEST TO NORTHEAST AS THE FRONT MOVES ACROSS THE COASTAL WATERS. COLD AIR ADVECTION WILL FOLLOW AND WINDS SPEED ARE EXPECTED TO INCREASE TO 20 TO 25 KNOTS FROM THE NORTHEAST LATE WEDNESDAY NIGHT. A SMALL CRAFT ADVISORY MAY BE LIKELY IF THE MODELS CONSISTENCY CONTINUES. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 PM MONDAY...NORTHEAST WINDS INITIALLY FROM 15-20 KNOTS AS HIGH PRESSURE BUILDS DOWN THE EAST COAST. SPEEDS WILL QUICKLY DIMINISH TO LESS THAN TEN KNOTS BY FRIDAY MORNING. WILL PROBABLY HAVE A MARGINAL SMALL CRAFT ADVISORY FOR SEAS AS WELL THURSDAY. WIND SHIFT OCCURS LATE FRIDAY TO SOUTHEAST AS THE AFOREMENTIONED HIGH QUICKLY MOVES OFFSHORE. SPEEDS WILL REMAIN LIGHT AND CONTINUE THROUGH SATURDAY. SIGNIFICANT SEAS WILL DROP TO AROUND TWO FEET. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...DRH LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 PM EST SUN DEC 2 2012 .SYNOPSIS... A STEADY SOUTHWEST FLOW WILL BRING WARM AND DRY CONDITIONS ACROSS THE AREA THROUGH TUESDAY. A COLD FRONT WILL APPROACH FROM THE WEST TUESDAY NIGHT AND CROSS THE AREA WEDNESDAY... USHERING IN COOLER WEATHER FOR THURSDAY. && .NEAR TERM /THROUGH MONDAY NIGHT/... AS OF 245 PM SUNDAY... THROUGH TONIGHT: OFFSHORE-CENTERED SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE WESTWARD THROUGH THE CAROLINAS AND SOUTHEAST STATES TONIGHT. A MID LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL TRACK QUICKLY EASTWARD ACROSS THE ST LAWRENCE VALLEY AND NORTHEAST STATES TONIGHT. WHILE THE BACKDOOR FRONT TRAILING THE LOW WILL HOLD WELL TO OUR NORTH... LIKELY DIPPING NO FURTHER SOUTH THAN THE MASON DIXON LINE... THE PREFRONTAL SURFACE-850 MB TROUGH EXTENDING SOUTHWEST OF THE LOW WILL SWEEP ACROSS VA AND NRN NC LATE TONIGHT. A FEW CONVECTION-ALLOWING MODELS INCLUDING THE HRRR AND LOCAL WRF SUGGEST THAT A THIN BAND OF LIGHT RAIN ACCOMPANYING THIS TROUGH WILL BRUSH ACROSS SRN VA OVERNIGHT... POTENTIALLY BREACHING THE NC STATE LINE... HOWEVER FORECAST SOUNDINGS SUGGEST THAT THE MOISTURE WILL BE QUITE SHALLOW AND THE OPPORTUNITY FOR FORCED ASCENT DUE TO QUICK ISENTROPIC UPGLIDE AT 295K-300K WILL BE TOO BRIEF FOR ANY MEASURABLE PRECIP IN THE NC/VA BORDER REGION. AS SUCH... WILL LEAVE OUT ANY POPS TONIGHT. HOWEVER... EVER-INCREASING LOW LEVEL THETA-E AND MASS CONVERGENCE WITH THE TROUGH EVIDENT AT 925-850 MB SHOULD BRING ABOUT QUITE A BIT OF CLOUDS TONIGHT OVER THE CENTRAL/NRN CWA... AND IN THE SE CWA... DEVELOPMENT OF FOG AND LOW STRATUS ARE LIKELY LATE TONIGHT GIVEN THE LIGHT WINDS... HIGH RH VALUES... AND FEWER CLOUDS. SREF PROBABILITIES OF DENSE FOG HERE IS OVER 60 PERCENT. COMPARED TO LAST NIGHT... EXPECT MUCH MILDER LOWS TONIGHT... 44-49. FOR MONDAY/MONDAY NIGHT: THE TAIL OF THE WEAK 850 MB TROUGH IS EXPECTED TO HANG BACK NEAR NRN NC THROUGH THE EARLY PART OF THE DAY WITH HIGH THETA-E POOLING OVER THE NRN PIEDMONT. EXPECT VARIABLY TO MOSTLY CLOUDY SKIES TO LINGER IN THIS AREA THROUGH THE NOON HOUR... BEFORE THE TROUGH PUSHES WELL EAST OUT TO SEA FOLLOWED BY THE RESUMPTION OF LIGHT ANTICYCLONIC 850 MB FLOW OVER NC BY LATE AFTERNOON. IN THE SOUTHERN CWA... PARTICULARLY THE SOUTHEAST... MORNING FOG/STRATUS WILL SLOWLY LIFT AND MIX OUT DURING THE MORNING... ASSISTED BY DRIER AIR ALOFT... AND EXPECT MORE SUNSHINE HERE THAN IN THE NORTHERN FORECAST AREA... AS RISING HEIGHTS ALOFT RESULT IN A DEEP RIDGING PATTERN FROM THE SURFACE UP THROUGH THE MID LEVELS YIELDING FEW IF ANY MID/HIGH CLOUDS. LOW LEVEL THICKNESSES CONTINUE TO CLIMB... APPROACHING 1370 METERS BY LATE AFTERNOON... ALTHOUGH THIS WARMING WILL BE TEMPERED BY THE LINGERING CLOUDS IN THE NORTHERN HALF OF THE CWA. HIGHS 70-74... SHY OF RECORD HIGHS (SEE BELOW). MOSTLY CLEAR SKIES AND A LIGHT SW FLOW MONDAY NIGHT SHOULD LEAD TO GOOD RADIATIONAL COOLING AND ANOTHER ROUND OF PATCHY FOG AREAWIDE. MORE ANOMALOUSLY WARM LOWS OF 45-50. -GIH && .SHORT TERM /TUESDAY THROUGH THURSDAY/... AS OF 250 PM SUNDAY... NEAR RECORD WARMTH WILL CONTINUE TUESDAY AS A SHORTWAVE RIDGE ALOFT SHIFTS EAST AHEAD OF A TROUGH MOVING THROUGH THE MIDWEST STATES. LOW LEVEL THICKNESSES AREA FORECAST TO START OUT NEAR 1360M TUESDAY MORNING...AND WITH FULL SUN TEMPS SHOULD AGAIN EACH THE LOW TO MID 70S. CIRRUS WILL BEGIN TO OVERSPREAD THE WESTERN HALF OF THE STATE DURING THE AFTERNOON...BUT MAY BE TOO LATE FOR IMPACT ON HIGHS AND/OR OFFSET BY A 10-12KT SOUTHWESTERLY SURFACE WIND. WILL GO WITH 69-74 NORTHWEST TO SOUTHEAST BASED ON THIS. THE SURFACE COLD FRONT WILL APPROACH FROM THE WEST TUESDAY NIGHT WHILE THE CORE OF THE UPPER TROUGH CROSSES THE GREAT LAKES REGION. THE MAIN BELT OF MOISTURE ACCOMPANYING THE FRONTAL ZONE IS FORECAST TO MOVE INTO THE WESTERN PIEDMONT PRIOR TO DAYBREAK WEDNESDAY AND THROUGH THE PIEDMONT BY MIDDAY...CLEARING THE COASTAL PLAIN BY EARLY EVENING. WHILE THE GFS AND ECMWF DIFFER SLIGHTLY REGARDING THE SOUTHERN EXTENT OF STRONGEST DCVA WITH THE UPPER TROUGH...NEITHER SHOW MUCH POTENTIAL FOR DEEP FORCING SOUTH OF VA. OF THE TWO MODELS...THE GFS SHOWS A SHARPER TROUGH AXIS AND MORE QPF...THOUGH MOSTLY LESS THAN A COUPLE TENTHS OF AN INCH. WHILE NOT AS WARM AS TUESDAY...THE PREFRONTAL AIRMASS WILL STILL BE UNSEASONABLY WARM AND MOIST WITH TEMPS IN THE 60S AND DEWPOINTS IN THE 50S. HOWEVER...VERY LITTLE COOLING ALOFT AND WEAK DYNAMICS SHOULD LIMIT INSTABILITY AND POTENTIAL FOR THUNDER OVER CENTRAL NC. THUS...WILL CONTINUE WITH JUST A CHANCE OF SHOWERS DURING THE DAY. THE AIRMASS BEHIND THE FRONT WILL NOT BE PARTICULARLY COOL...BUT SHOULD BRING TEMPS BACK DOWN TO NEAR NORMAL THURSDAY AS HIGH PRESSURE AND NORTHEASTERLY WINDS EXTEND SOUTH FROM EASTERN CANADA. HIGHS THURSDAY IN THE LOW TO MID 50S...WITH MOSTLY MID 30S WEDNESDAY AND THURSDAY NIGHTS. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 250 PM SUNDAY... THE LARGE SCALE PATTERN BECOMES LARGELY DOMINATED BY A BROAD AND POSITIVELY TILTED TROUGH OVER THE WESTERN US AND RIDGING ALONG THE WESTERN ATLANTIC DURING THE EXTENDED PERIOD. THIS SHOULD PATTERN SHOULD LEAD TO A SLOW MOVING COLD FRONT...AT LEAST INITIALLY...FROM THE DEEP SOUTH TO THE GREAT LAKES REGION...WHILE ADDITIONAL NORTHERN STREAM ENERGY ATTEMPTS TO MOVE SOUTH OUT OF CANADA AND INTO THE MEAN TROUGH. MEDIUM RANGE MODELS CURRENTLY SHOW THE FRONTAL ZONE REMAINING WEST OF THE MOUNTAINS THROUGH SATURDAY...WITH THE ECMWF THE ONLY MODEL TO PUSH THE COLD FRONT INTO THE CAROLINAS ON SUNDAY. FOR NOW...WILL TAKE THE MIDDLE ROAD...SHOWING ONLY SLOWLY INCREASING POPS FROM WEST TO EAST LATE SATURDAY INTO SUNDAY. DESPITE THE POTENTIAL FOR QUITE A BIT OF CLOUD COVER DURING THE PERIODS..TEMPS WILL LIKELY BE AT LEAST 5-10 DEGREES ABOVE NORMAL. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 130 PM SUNDAY... VFR CIGS AND VSBYS WILL HOLD THROUGH MID EVENING WITH SURFACE HIGH PRESSURE SPANNING THE AREA AND WARM/DRY AIR ALOFT. AN UPPER LEVEL TROUGH PASSING BY QUICKLY TO OUR NORTH WILL EXIT THE COAST LATER THIS AFTERNOON... TAKING THE HIGH CLOUDS WITH IT. DAYTIME SCATTERED TO BROKEN STRATOCUMULUS WILL PERSIST THROUGH THE REST OF THE AFTERNOON BEFORE DISSIPATING LATE. CLOUDS WILL REDEVELOP AFTER SUNSET... WITH A WARM LOW LEVEL FLOW FROM THE SW. VERY LIGHT WINDS AT FAY/RWI AND GREATER LOW LEVEL MOISTURE WILL RESULT IN IFR CIGS/VSBYS DEVELOPING AFTER 07Z. AT RDU... IFR VSBYS ARE EXPECTED... WHILE AT GSO/INT... VSBYS WILL TREND TO MVFR... DUE TO THE SLIGHTLY STRONGER WINDS AT THESE THREE LOCATIONS FAVORING DEVELOPMENT OF VFR-LEVEL STRATUS OVERNIGHT. VFR CONDITIONS WILL RETURN AT ALL SITES AFTER 13Z AT INT/GSO/RDU... AND AFTER 15Z AT FAY/RWI. LOOKING BEYOND 18Z MONDAY... MVFR/IFR FOG IS AGAIN POSSIBLE LATE MONDAY NIGHT/TUESDAY MORNING... AND AGAIN LATE TUESDAY NIGHT. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF MVFR CIGS IN RAIN LATE TUESDAY NIGHT INTO MID AFTERNOON WEDNESDAY. THE FRONT IS THEN EXPECTED TO MOVE TO OUR SOUTH... BRINGING A RETURN TO VFR CONDITIONS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT... THEN MVFR CIGS MAY REDEVELOP ON FRIDAY AS THE FRONT MOVES BACK NORTHWARD AS A WARM FRONT. -GIH && .CLIMATE... RECORD MAX TEMPS FOR DECEMBER 3RD AND DECEMBER 4TH. DECEMBER 3RD RDU 77 1991 GSO 72 1970 FAY 80 1991 DECEMBER 4TH RDU 79 1978 GSO 73 1998 FAY 81 1991 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...BLS LONG TERM...BLS AVIATION...HARTFIELD CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
248 PM EST SUN DEC 2 2012 .SYNOPSIS... A STEADY SOUTHWEST FLOW WILL BRING WARM AND DRY CONDITIONS ACROSS THE AREA THROUGH TUESDAY. A COLD FRONT WILL APPROACH FROM THE WEST TUESDAY NIGHT AND CROSS THE AREA WEDNESDAY... USHERING IN COOLER WEATHER FOR THURSDAY. && .NEAR TERM /THROUGH MONDAY NIGHT/... AS OF 245 PM SUNDAY... THROUGH TONIGHT: OFFSHORE-CENTERED SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE WESTWARD THROUGH THE CAROLINAS AND SOUTHEAST STATES TONIGHT. A MID LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL TRACK QUICKLY EASTWARD ACROSS THE ST LAWRENCE VALLEY AND NORTHEAST STATES TONIGHT. WHILE THE BACKDOOR FRONT TRAILING THE LOW WILL HOLD WELL TO OUR NORTH... LIKELY DIPPING NO FURTHER SOUTH THAN THE MASON DIXON LINE... THE PREFRONTAL SURFACE-850 MB TROUGH EXTENDING SOUTHWEST OF THE LOW WILL SWEEP ACROSS VA AND NRN NC LATE TONIGHT. A FEW CONVECTION-ALLOWING MODELS INCLUDING THE HRRR AND LOCAL WRF SUGGEST THAT A THIN BAND OF LIGHT RAIN ACCOMPANYING THIS TROUGH WILL BRUSH ACROSS SRN VA OVERNIGHT... POTENTIALLY BREACHING THE NC STATE LINE... HOWEVER FORECAST SOUNDINGS SUGGEST THAT THE MOISTURE WILL BE QUITE SHALLOW AND THE OPPORTUNITY FOR FORCED ASCENT DUE TO QUICK ISENTROPIC UPGLIDE AT 295K-300K WILL BE TOO BRIEF FOR ANY MEASURABLE PRECIP IN THE NC/VA BORDER REGION. AS SUCH... WILL LEAVE OUT ANY POPS TONIGHT. HOWEVER... EVER-INCREASING LOW LEVEL THETA-E AND MASS CONVERGENCE WITH THE TROUGH EVIDENT AT 925-850 MB SHOULD BRING ABOUT QUITE A BIT OF CLOUDS TONIGHT OVER THE CENTRAL/NRN CWA... AND IN THE SE CWA... DEVELOPMENT OF FOG AND LOW STRATUS ARE LIKELY LATE TONIGHT GIVEN THE LIGHT WINDS... HIGH RH VALUES... AND FEWER CLOUDS. SREF PROBABILITIES OF DENSE FOG HERE IS OVER 60 PERCENT. COMPARED TO LAST NIGHT... EXPECT MUCH MILDER LOWS TONIGHT... 44-49. FOR MONDAY/MONDAY NIGHT: THE TAIL OF THE WEAK 850 MB TROUGH IS EXPECTED TO HANG BACK NEAR NRN NC THROUGH THE EARLY PART OF THE DAY WITH HIGH THETA-E POOLING OVER THE NRN PIEDMONT. EXPECT VARIABLY TO MOSTLY CLOUDY SKIES TO LINGER IN THIS AREA THROUGH THE NOON HOUR... BEFORE THE TROUGH PUSHES WELL EAST OUT TO SEA FOLLOWED BY THE RESUMPTION OF LIGHT ANTICYCLONIC 850 MB FLOW OVER NC BY LATE AFTERNOON. IN THE SOUTHERN CWA... PARTICULARLY THE SOUTHEAST... MORNING FOG/STRATUS WILL SLOWLY LIFT AND MIX OUT DURING THE MORNING... ASSISTED BY DRIER AIR ALOFT... AND EXPECT MORE SUNSHINE HERE THAN IN THE NORTHERN FORECAST AREA... AS RISING HEIGHTS ALOFT RESULT IN A DEEP RIDGING PATTERN FROM THE SURFACE UP THROUGH THE MID LEVELS YIELDING FEW IF ANY MID/HIGH CLOUDS. LOW LEVEL THICKNESSES CONTINUE TO CLIMB... APPROACHING 1370 METERS BY LATE AFTERNOON... ALTHOUGH THIS WARMING WILL BE TEMPERED BY THE LINGERING CLOUDS IN THE NORTHERN HALF OF THE CWA. HIGHS 70-74... SHY OF RECORD HIGHS (SEE BELOW). MOSTLY CLEAR SKIES AND A LIGHT SW FLOW MONDAY NIGHT SHOULD LEAD TO GOOD RADIATIONAL COOLING AND ANOTHER ROUND OF PATCHY FOG AREAWIDE. MORE ANOMALOUSLY WARM LOWS OF 45-50. -GIH && .SHORT TERM /TUESDAY/... AS OF 300 AM SUNDAY... TUESDAY...FORECAST AREA WILL BE BETWEEN AN AREA OF HIGH PRESSURE CENTERED OFFSHORE OF THE SE U.S. AND A POSITIVE-TILT S/W CROSSING THE GREAT LAKES/OH VALLEY. THIS WILL RESULT IN A DEEP SW FLOW OVER CENTRAL NC. THIS SCENARIO IS SUPPORTIVE OF VERY WARM AND MAINLY DRY CONDITIONS. EVEN THOUGH LOW LEVEL THICKNESSES LOWER INTO THE 1360S...PLENTY OF SUNSHINE AND STEADY SW FLOW SHOULD BOOST TEMPS BACK INTO THE LOWER 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 230 AM SUNDAY... TUESDAY NIGHT THROUGH WEDNESDAY NIGHT: MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE TIMING AND STRENGTH OF THE NEXT SYSTEM TO AFFECT THE AREA MIDWEEK. BEST FORCING APPEARS TO CONTINUE TO BE LOCATED TO THE NORTH OF THE REGION... WHILE ANY GOOD SURFACE INSTABILITY WILL REMAIN TO THE SOUTH OF THE AREA. THUS... MODELS CONTINUE TO SHOW NOT MUCH IN THE WAY OF RAINFALL AMOUNTS... ALTHOUGH MORE THAN YESTERDAY AT THIS TIME. THUS... WILL CONTINUE TO GO WITH A LOW END CHANCE POPS FOR NOW FOR WEDNESDAY MORNING INTO THE AFTERNOON. WRT THE TIMING OF THE COLD FRONT... EXPECT THE FRONT TO MOVE INTO THE NORTHERN/NORTHWESTERN PIEDMONT BY MID MORNING AND BE TO THE SOUTH/SOUTHEAST OF THE AREA BY 00Z THURSDAY. HIGH TEMPS WILL BE TRICKY AND DEPENDENT ON HOW QUICKLY THE FRONT ACTUALLY MOVES THROUGH THE AREA... ALONG WITH HOW QUICKLY SKIES ARE ABLE TO CLEAR. FOR NOW WILL CONTINUE TO GO WITH HIGH TEMPS RANGING FROM THE LOWER 60S NORTH TO THE MID TO UPPER 60S SOUTH/SOUTHEAST. LOW TEMPS WEDNESDAY MORNING ARE EXPECTED TO BE RATHER MILD FOR THIS TIME OF YEAR WITH EXPECT PARTLY TO MOSTLY CLOUDY SKIES AND SOUTHWESTERLY LOW LEVEL FLOW. THUS... WILL GO WITH LOWS IN THE LOWER TO MID 50S FOR WEDNESDAY MORNING. EXPECT CLEARING SKIES WEDNESDAY EVENING AS THE FRONT SETTLES TO THE SOUTH OF THE REGION AND HIGH PRESSURE BUILDS SOUTHWARD INTO THE AREA. LOWS THURSDAY MORNING ARE EXPECTED TO BE MUCH COOLER AS DRIER AND COLDER AIR FILTERS INTO THE REGION. WILL GO WITH LOWS THURSDAY MORNING GENERALLY IN THE MID TO UPPER 30S. THURSDAY THROUGH SATURDAY: SURFACE HIGH PRESSURE WILL QUICKLY MOVE ACROSS THE REGION LATE WEEK... WITH BRIEF WEAK S/W RIDGING MOVING ACROSS THE AREA (MOSTLY ZONAL FLOW). THE NEXT DEVELOPING TROUGH AND ASSOCIATED COLD FRONT WILL APPROACH THE REGION ON FRIDAY FROM THE WEST. HOWEVER... MODELS CONTINUE TO STRUGGLE WITH THE EVOLUTION OF THIS TROUGH AND ASSOCIATED COLD FRONT. THUS... CONFIDENCE IN THE FORECAST BY NEXT WEEK IS RATHER LOW (LARGE SWINGS IN THE MODELS FROM RUN TO RUN ALONG WITH MODEL DISCREPANCIES). HOWEVER... IT STILL APPEARS WE SHOULD SEE A WARMING TREND BY FRIDAY... POTENTIALLY LASTING INTO SATURDAY (MAYBE EVEN BEYOND). THUS... EXPECT HIGH TEMPS THURSDAY IN THE LOWER TO MID 50S... WARMING TO THE 60S BY FRIDAY INTO SATURDAY (WITH MAYBE EVEN SOME LOWER 70S ACROSS THE SOUTH BY SATURDAY... GIVEN THE LATEST GUIDANCE HOLDS ANY FROPA AND ANY PRECIP TO THE WEST OF THE AREA NOW ON SATURDAY. LOW TEMPS DURING THIS TIMEFRAME ARE EXPECTED TO BE IN THE MID TO UPPER 30S FRIDAY MORNING TO LOWER TO MID 40S BY SATURDAY MORNING. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 130 PM SUNDAY... VFR CIGS AND VSBYS WILL HOLD THROUGH MID EVENING WITH SURFACE HIGH PRESSURE SPANNING THE AREA AND WARM/DRY AIR ALOFT. AN UPPER LEVEL TROUGH PASSING BY QUICKLY TO OUR NORTH WILL EXIT THE COAST LATER THIS AFTERNOON... TAKING THE HIGH CLOUDS WITH IT. DAYTIME SCATTERED TO BROKEN STRATOCUMULUS WILL PERSIST THROUGH THE REST OF THE AFTERNOON BEFORE DISSIPATING LATE. CLOUDS WILL REDEVELOP AFTER SUNSET... WITH A WARM LOW LEVEL FLOW FROM THE SW. VERY LIGHT WINDS AT FAY/RWI AND GREATER LOW LEVEL MOISTURE WILL RESULT IN IFR CIGS/VSBYS DEVELOPING AFTER 07Z. AT RDU... IFR VSBYS ARE EXPECTED... WHILE AT GSO/INT... VSBYS WILL TREND TO MVFR... DUE TO THE SLIGHTLY STRONGER WINDS AT THESE THREE LOCATIONS FAVORING DEVELOPMENT OF VFR-LEVEL STRATUS OVERNIGHT. VFR CONDITIONS WILL RETURN AT ALL SITES AFTER 13Z AT INT/GSO/RDU... AND AFTER 15Z AT FAY/RWI. LOOKING BEYOND 18Z MONDAY... MVFR/IFR FOG IS AGAIN POSSIBLE LATE MONDAY NIGHT/TUESDAY MORNING... AND AGAIN LATE TUESDAY NIGHT. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF MVFR CIGS IN RAIN LATE TUESDAY NIGHT INTO MID AFTERNOON WEDNESDAY. THE FRONT IS THEN EXPECTED TO MOVE TO OUR SOUTH... BRINGING A RETURN TO VFR CONDITIONS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT... THEN MVFR CIGS MAY REDEVELOP ON FRIDAY AS THE FRONT MOVES BACK NORTHWARD AS A WARM FRONT. -GIH && .CLIMATE... RECORD MAX TEMPS FOR DECEMBER 3RD AND DECEMBER 4TH. DECEMBER 3RD RDU 77 1991 GSO 72 1970 FAY 80 1991 DECEMBER 4TH RDU 79 1978 GSO 73 1998 FAY 81 1991 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...WSS LONG TERM...BSD AVIATION...HARTFIELD CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1015 PM CST SAT DEC 1 2012 .DISCUSSION... DENSE FOG HAS EXPANDED DURING THE LATE EVENING HOURS...PROMPTING A DENSE FOG ADVISORY FOR MUCH OF THE FORECAST AREA EXCEPT FOR THE FAR SOUTH. THE ENTIRE ADVISORY EXPIRES AT 9 AM CST SUNDAY...AND LATER SHIFTS CAN ADJUST AS NEEDED. && .AVIATION... LOW STRATUS REDEVELOPING IN THE MISSOURI RIVER VALLEY IS PROMPTING AMENDMENTS KEEP IFR/LIFR CONDITIONS IN LONGER OVERNIGHT AT KBIS/KISN. THE LATEST RAP HAS A GOOD HANDLE ON THE LOW LEVEL MOISTURE AND WILL GENERALLY FOLLOW ITS SLOWER CLEARING FOR THE NEXT TAF ISSUANCE. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR NDZ001>005-009>013- 017>023-025-035>037. && $$ DISCUSSION/AVIATION...RK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
422 PM EST SUN DEC 2 2012 .SYNOPSIS... A WEAK BOUNDARY NEAR THE AREA TONIGHT WILL PUSH NORTH OF THE REGION ON MONDAY. A COLD FRONT WILL MOVE THROUGH THE AREA ON TUESDAY. HIGH PRESSURE WILL BUILD INTO THE REGION FOR WEDNESDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... MORE WIDESPREAD SHOWER ACTIVITY IS CURRENTLY LOCATED ACROSS SE PORTIONS OF THE FA ACROSS NORTHERN KENTUCKY. ELSEWHERE ACROSS THE FA...SOME LIGHT SHOWER AND IN SOME INSTANCES DRIZZLE ACTIVITY IS OCCURRING. WITH ISENTROPIC LIFT ACROSS A LARGE PORTION OF THE AREA THROUGH THE OVERNIGHT HOURS HAVE KEPT PRECIPITATION CHANCES IN THE FORECAST FOR THE FA. SOUTHERN PORTIONS OF THE FA ARE MORE LIKELY TO SEE SHOWER TYPE ACTIVITY WHILE NORTHERN PORTIONS OF THE FA ARE MORE LIKELY TO SEE DRIZZLE DURING THE OVERNIGHT HOURS. IN ADDITION...VISIBILITIES WILL BE REDUCED TONIGHT WITH SOME FOG. HAVE FOG IN THE FORECAST ACROSS NORTHERN PORTIONS OF THE FA WHERE VISIBILITIES WILL BE REDUCED THE MOST. TEMPERATURES WILL DROP VERY LITTLE ACROSS THE FA THROUGH THE OVERNIGHT HOURS. TEMPERATURES ARE CURRENTLY IN THE 50S AND EXPECT LOW TEMPERATURES ONLY TO BE IN THE LOW 50S ACROSS MOST OF THE AREA OVERNIGHT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... SHOWER ACTIVITY WILL LIFT TO THE NORTH ON MONDAY AND PRECIPITATION CHANCES WILL BEGIN TO COME TO AN END BY THE MIDDLE OF THE DAY. CLOUD COVER WILL ALSO DECREASE ACROSS THE AREA AND WITH DECENT SOUTHERLY FLOW TEMPERATURES WILL RISE INTO THE MIDDLE 60S TO AROUND 70 DEGREES. CLOUD COVER WILL BEGIN TO INCREASE ACROSS THE AREA MONDAY NIGHT AS A COLD FRONT APPROACHES THE AREA. PRECIPITATION WILL HOLD OFF UNTIL AFTER MIDNIGHT MONDAY NIGHT HOWEVER RAIN SHOWERS WILL BEGIN TO MOVE INTO NW PORTIONS OF THE FA BY MORNING. RAIN SHOWERS WILL OVERSPREAD THE FA DURING THE DAY ON TUESDAY. A LITTLE BIT OF WEAK INSTABILITY CAN BE FOUND ACROSS SE PORTIONS OF THE FA ON TUESDAY AFTERNOON AND THEREFORE ADDED A SLIGHT CHANCE OF THUNDER INTO THE FORECAST ACROSS THAT AREA FOR A FEW HOURS. THE COLD FRONT WILL MOVE THROUGH THE FA DURING THE AFTERNOON AND INTO THE EVENING HOURS ON TUESDAY. PRECIPITATION WILL TAPER OFF TUESDAY EVENING AND INTO TUESDAY NIGHT. COOLER AIR WILL FILTER INTO THE AREA TUESDAY NIGHT WITH LOWS DROPPING DOWN INTO THE LOW TO MIDDLE 30S BY WEDNESDAY MORNING. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD INTO THE REGION ON WEDNESDAY DROPPING TEMPERATURES CLOSER TO SEASONAL AVERAGE. BUT THIS WILL BE SHORT-LIVED AS THE HIGH MOVES OFF TO THE EAST THURSDAY AND TEMPERATURES REBOUND. A FRONT WILL DROP INTO THE REGION ON FRIDAY AND BECOME QUASI-STATIONARY THROUGH THE WEEKEND. WHILE THERE ARE MODEL DIFFERENCES ON EXACTLY WHERE THIS BOUNDARY WILL SET UP...IT DOES BRING THE POTENTIAL FOR UNSETTLED CONDITIONS THROUGH THE END OF THE PERIOD...ESPECIALLY AS WAVES OF LOW PRESSURE TRAVEL ALONG THE STALLED FRONT. AT THIS POINT HIGHER CONFIDENCE IN WET CONDITIONS IS FOR FRIDAY AFTERNOON INTO FRIDAY NIGHT PARTICULARLY IN SOUTHERN ZONES. NOT OUT OF THE QUESTION THAT THERE COULD BE SOME LIGHT SNOW MIXED IN AT TIMES OVER THE WEEKEND IN THE FAR NORTH. BUT THAT IS ALL DEPENDENT ON STRENGTH AND LOCATION OF THE BOUNDARY. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... MORE WIDESPREAD PCPN ASSOCIATED WITH A WEAK BOUNDARY HAS PUSHED SOUTH AND EAST OF THE TAF SITES EARLY THIS AFTERNOON. MVFR TO OCCASIONALLY IFR CIGS HAVE PUSHED DOWN BEHIND THE BOUNDARY AND WILL LIKELY REMAIN IN PLACE THROUGH MUCH OF THE TAF PERIOD. IN FACT...BOTH THE NAM AND LATEST SEVERAL RUNS OF THE RAP ARE KEEPING THINGS PRETTY MUCH SOCKED IN THROUGH AT LEAST TONIGHT. WILL THEREFORE KEEP THE TAFS PRETTY PESSIMISTIC WITH PREVAILING IFR CONDITIONS BY TONIGHT. THE BOUNDARY WILL STALL OUT TO OUR SOUTH THIS EVENING AND THEN BEGIN TO LIFT BACK TO THE NORTH. THIS COULD RESULT IN SOME LINGERING SHOWER ACTIVITY...ESPECIALLY AT THE SOUTHERN TAF SITES THROUGH TONIGHT. AS THE BOUNDARY BEGINS TO LIFT NORTH...EXPECT IMPROVING CONDITIONS FROM THE SOUTH TOWARD THE END OF THE TAF PERIOD. OUTLOOK...MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...NOVAK NEAR TERM...NOVAK SHORT TERM...NOVAK LONG TERM... AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1259 PM EST SUN DEC 2 2012 .SYNOPSIS... A WEAK FRONT DROPPING INTO OHIO WILL BRING SCATTERED SHOWERS TODAY INTO TONIGHT. THE FRONT WILL LIFT BACK NORTH ON MONDAY...WITH UNSEASONABLY WARM TEMPERATURES CONTINUING. A STRONGER COLD FRONT WILL MOVE THROUGH ON TUESDAY OFFERING WIDESPREAD SHOWERS AND COOLER TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHORTWAVE ENERGY PROGRESSING EAST ACROSS OUR AREA THIS MORNING WITH LEADING EDGE OF PCPN RIGHT ALONG INTERSTATE 71. THIS LINES UP WITH THE AREA OF BEST LOW LEVEL CONVERGENCE THAT WILL LAY OUT ALONG THE OHIO RIVER HEADING INTO THIS AFTERNOON. WILL THEREFORE ALLOW FOR HIGH POPS TO PROGRESS EAST OVER THE NEXT COUPLE OF HOURS...WITH BEST CHANCE THEN LINING UP ACROSS OUR SOUTH THROUGH THIS AFTERNOON. WEAK ELEVATED INSTABILITIES WILL ALSO PERSIST INTO THIS AFTERNOON SO WILL LIKELY CONTINUE TO SEE SOME ISOLATED LIGHTNING STRIKES. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... WITH THE PASSAGE OF MID LEVEL SHORTWAVE THE FLOW WILL AMPLIFY WITH RIDGING BUILDING OVER THE GREAT LAKES/OH VLY ON TONIGHT INTO MONDAY. SFC FRONTAL BOUNDARY TO STALL OUT E-W TONIGHT ACRS SRN OHIO AND THEN RETURN NORTH ON MONDAY. WILL DIMINISH POPS TONIGHT WITH THE LOSS OF UPPER SUPPORT. MILD TEMPERATURES TO CONTINUE WITH TONIGHTS LOWS ABOVE NORMAL HIGHS...RANGING FROM NEAR 50 NORTH TO THE MID 50S SOUTH. ON MONDAY WILL LIMIT MENTION OF SHOWERS TO SLIGHT CHC EARLY AND PIVOT THESE POPS NORTH OUT OF ILNS FA AS THE FRONT LIFTS NORTH AND THE MID/UPR LEVEL RIDGE BUILDS. WARM TEMPS TO CONTINUE WITH MONDAYS HIGHS AROUND 20 DEGREES ABOVE NORMAL...RANGING FROM THE MID 60S NORTH TO 70 SOUTH. UPPER LEVEL TROF TO TRANSLATE EAST ACRS THE NATIONS MID SECTION AND ASSOCIATED SFC FRONT TO SWEEP EAST ACRS ILNS FA TUESDAY AFTERNOON. WILL INTRODUCE CHANCE POPS INTO THE WEST LATE MONDAY NIGHT AND THEN RAMP UP TO CATEGORICAL WITH FROPA ON TUESDAY. MILD TEMPS TO CONTINUE MONDAY NIGHT WITH LOWS IN THE LOWER/MIDDLE 50S. TUESDAY WILL BE A TRANSITION DAY WITH HIGHS RANGING FROM THE UPPER 50S NW TO THE UPPER 60S SE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SHOWERS WILL ACCOMPANY A COLD FRONT THAT WILL MOVE ACROSS THE REGION TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD IN WEDNESDAY AND MOVE OFF TO THE EAST ON THURSDAY. FAIRLY GOOD MODEL AGREEMENT THAT LOW PRESSURE WILL DEVELOP IN THE OZARKS THURSDAY NIGHT AND MOVE UP THE OHIO VALLEY FRIDAY AND FRIDAY NIGHT. THIS WILL BRING RAIN TO THE REGION. HIGH PRESSURE WILL BUILD BACK IN FROM THE NORTHWEST ON SATURDAY. TEMPERATURES WILL BE AT OR ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... MORE WIDESPREAD PCPN ASSOCIATED WITH A WEAK BOUNDARY HAS PUSHED SOUTH AND EAST OF THE TAF SITES EARLY THIS AFTERNOON. MVFR TO OCCASIONALLY IFR CIGS HAVE PUSHED DOWN BEHIND THE BOUNDARY AND WILL LIKELY REMAIN IN PLACE THROUGH MUCH OF THE TAF PERIOD. IN FACT...BOTH THE NAM AND LATEST SEVERAL RUNS OF THE RAP ARE KEEPING THINGS PRETTY MUCH SOCKED IN THROUGH AT LEAST TONIGHT. WILL THEREFORE KEEP THE TAFS PRETTY PESSIMISTIC WITH PREVAILING IFR CONDITIONS BY TONIGHT. THE BOUNDARY WILL STALL OUT TO OUR SOUTH THIS EVENING AND THEN BEGIN TO LIFT BACK TO THE NORTH. THIS COULD RESULT IN SOME LINGERING SHOWER ACTIVITY...ESPECIALLY AT THE SOUTHERN TAF SITES THROUGH TONIGHT. AS THE BOUNDARY BEGINS TO LIFT NORTH...EXPECT IMPROVING CONDITIONS FROM THE SOUTH TOWARD THE END OF THE TAF PERIOD. OUTLOOK...MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...JGL SHORT TERM...AR LONG TERM... AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
337 AM EST SUN DEC 2 2012 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES TODAY AND DRAG A WEAK COLD FRONT ACROSS THE LOCAL AREA. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON MONDAY AND WILL BE FOLLOWED BY A STRONGER COLD FRONT ON TUESDAY. HIGH PRESSURE IS EXPECTED TO BUILD OVER THE OHIO VALLEY FOR THE MIDDLE PORTION OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN AREA OF SHOWERS CONTINUES TO MOVE MOVE ENE ACROSS THE AREA THIS MORNING. MOST OF THIS PRECIP IS OVER LAKE ERIE. MODELS CONTINUE TO SHOW MORE PRECIP DEVELOPING THIS MORNING OVER NW OH AND MOVING ACROSS THE REMAINDER OF THE AREA TODAY. THIS PRECIP WILL BE ASSOCIATED WITH A FRONTAL BOUNDARY. EXPECT DEWPOINTS TO SURGE TO CLOSE TO 50 DEGREES TODAY. THIS COULD BE ENOUGH FOR SOME EMBEDDED THUNDER IN THE STRONGER SHOWERS. WILL CONTINUE WITH HIGH POPS ALL AREAS. THE FRONT AND MOST OF THE PRECIP SHOULD BE EAST OF THE AREA BY SUNSET. PLACES LIKE KTOL AND KFDY WILL LIKELY BE DRY AFTER 18Z. 850 MB TEMPS WILL SURGE TO AROUND PLUS 8 TODAY. THIS MEANS EVEN WITH CLOUDS AND RAIN...TEMPS SHOULD BE A DEGREE OR TWO WARMER THAN SATURDAY MOST AREAS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THERE COULD BE SOME LINGERING SHOWERS IN THE EAST EARLY TONIGHT. A WARM FRONT IS EXPECTED TO DEVELOP AND LIFT NORTH ACROSS THE AREA ON MONDAY. EXPECT SOME VIRGA AND PERHAPS SOME LIGHT PRECIP WITH THIS FRONT AND WILL CONTINUE WITH A SMALL MENTION IN THE FORECAST. BETTER CHANCES FOR SHOWERS WILL COME MONDAY NIGHT AND TUESDAY AS A STRONGER COLD FRONT RACES EAST ACROSS THE REGION. THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS FEATURE AND HAVE MADE ONLY MINOR ADJUSTMENTS TO THE FORECAST. DEWPOINTS WILL AGAIN GET INTO THE LOWER 50S SO LATER SHIFTS MADE EVENTUALLY NEED TO ADD THUNDER. DRIER AND COLDER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT ON TUESDAY NINTH AND WEDNESDAY. A SURFACE RIDGE WILL BE OVERHEAD BY WEDNESDAY NIGHT. THERE WILL BE A SMALL WINDOW FOR SOME LAKE EFFECT SHOWERS TUESDAY NIGHT INTO WEDNESDAY EAST OF CLEVELAND. BUT...BY EARLY WEDNESDAY AFTERNOON THE SETUP BECOMES PRETTY UNFAVORABLE WITH AN EASTERLY COMPONENT TO THE WIND. CRITICAL THICKNESSES SUGGEST IT WILL BE COLD ENOUGH FOR AT LEAST MIXED PRECIP. NOT MUCH IF ANY ACCUMULATION IS EXPECTED. WILL TRY FOR DRY WEATHER ON WEDNESDAY NIGHT. HAVE NOT CHANGED THE PREVIOUS TEMP FORECAST MUCH. JUST SOME MINOR ADJUSTMENTS HERE AND THERE. && .LONG TERM /THURSDAY THROUGH SATURDAY/... LITTLE CHANGE WITH THE END OF THE WEEK. THURSDAY HIGH PRESSURE SHIFTS EAST. A COLD FRONT WILL BE MAKING ITS WAY ACROSS THE EASTERN GREAT LAKES LATER FRIDAY...BUT THEN STALLS ACROSS THE OHIO VALLEY FOR SATURDAY. THESE LARGE SCALE FEATURES ARE FAIRLY WELL AGREED UPON...BUT DIFFERENCES REMAIN AS EXPECTED WITH THE DETAILS. THE TIMING AND THE SOUTHERN EXTENT OF THE FRONT WILL DETERMINE OUR LOW TEMPERATURES ON FRIDAY NIGHT AND THEN ALSO HIGHS ON SATURDAY DEPENDING ON WHERE THE FRONT IS WHEN A STRONGER WAVE DEVELOPS ON THE FRONT. HOW MUCH COLD AIR WILL IT DRAW IN ON THE NORTH SIDE WILL BE THE QUESTION. RIGHT NOW SEASONABLE THURSDAY INTO FRIDAY. WILL BRING A CHANCE OF RAIN SHOWERS IN FRIDAY...BUT WILL MENTION BOTH RAIN AND SNOW SHOWERS FOR FRIDAY NIGHT AND SATURDAY AS WE SLOWLY GET COLDER. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... THE LOW LEVEL JET IS ON THE INCREASE AHEAD OF A WEAKENING COLD FRONT OVERNIGHT. THE SHOWERS ARE BEGINNING TO DEVELOP. THE HRRR MODEL IS NOW DEVELOPING THE SHOWERS A LITTLE SLOWER. WE WILL HAVE SOME SCATTERED SHOWERS AHEAD OF THE MAIN BAND OF SHOWERS. AT THIS TIME NO MENTION OF THUNDER BUT ISOLATED THUNDERSTORMS ARE POSSIBLE LATE TONIGHT THROUGH MID AFTERNOON ON SUNDAY. WINDS WILL BE ON THE INCREASE OVERNIGHT AND THAT SHOULD HELP PREVENT LLWS. MAINLY VFR OVERNIGHT AND THEN SLOWLY DECREASING THE CEILINGS TO IFR ESPECIALLY FOR LATE SUNDAY MORNING AND AFTERNOON...MODERATELY CONFIDENT IN THAT. CONDITIONS WILL STAY IFR ESPECIALLY SOUTH OF THE LAKE SUNDAY EVENING. OUTLOOK...NON VFR LIKELY LATE SUNDAY NIGHT THROUGH TUESDAY. && .MARINE... GRADIENT FAIRLY TIGHT AHEAD OF A COLD FRONT SCHEDULED TO COME ACROSS THE LAKE TODAY SO WILL CONTINUE TO SEE A STIFF SOUTHWEST FLOW TO START OFF THE DAY DECREASING SLOWLY BY LATER THIS AFTERNOON. WILL KEEP THE SMALL CRAFT ADVISORY SET UP AS IS. HIGH PRESSURE BRIEFLY IN PLACE TONIGHT THEN ANOTHER WARM FRONT LIFTS NORTH MONDAY. SO WINDS WILL CALM WITH THE HIGH AND THEN BE OUT OF THE SOUTH AGAIN FOR MONDAY. MONDAY NIGHT WILL BE A REPEAT OF CURRENT CONDITIONS AND WILL SEE SOUTHWEST WINDS PICK UP AGAIN AHEAD OF A COLD FRONT FOR TUESDAY. COULD SEE A SMALL CRAFT ADVISORY AGAIN. THE HIGH MOVES ACROSS THE GREAT LAKES WEDNESDAY...STAYING NORTH OF THE LAKE AND MAINTAINING A NORTHERLY COMPONENT FLOW. WILL BE ON THE BACKSIDE OF THE HIGH FOR THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LEZ147>149. SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR LEZ142>146. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...OUDEMAN AVIATION...KIELTYKA MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1147 PM EST SAT DEC 1 2012 .SYNOPSIS... SHOWERS WILL DEVELOP ON SUNDAY AS A LOW PRESSURE SYSTEM TRACKS ACROSS THE UPPER GREAT LAKES. ANOTHER WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON MONDAY WITH WELL ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL ARRIVE ON TUESDAY WITH A STRONGER COLD FRONT EARLY WEDNESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... CONTINUING TO WATCH REGIONAL RADAR WITH SHOWERS DEVELOPING OFF TO THE WEST EARLY TONIGHT. LITTLE CHANGE WITH RECENT MODEL RUNS ON EXPECTATIONS FOR SHOWERS TO BUILD INTO THE AREA LATE TONIGHT THROUGH SUNDAY MORNING. MADE SOME SMALL ADJUSTMENTS TO POPS BETWEEN 06-12Z ACROSS THE AREA...BUT OTHERWISE CONTINUED WITH THE THUNDER ACROSS THE WEST. TEMP TRENDS CONTINUE TO LOOK REASONABLE ALSO. PREVIOUS DISCUSSION...WATER VAPOR IMAGERY SHOWS A PLUME OF MOISTURE ADVANCING TOWARDS THE REGION AHEAD OF A SERIES OF SHORTWAVES MOVING THROUGH THE UPPER LEVEL FLOW. 12Z RAOBS SHOWED 850MB DEWPOINTS AS HIGH AS 8C NOSING UP THE MISSISSIPPI VALLEY WHICH WILL ADVANCE TO NW OHIO BY 12Z. THE ASSOCIATED SURFACE TROUGH APPROACHING MINNESOTA WILL SLIDE NORTHEAST ACROSS THE UPPER GREAT LAKES...MAINTAINING SOUTHERLY WINDS IN OUR FORECAST AREA OVERNIGHT. ALTHOUGH UPSTREAM RADARS SHOW A LACK OF PRECIPITATION AT THIS TIME...A LOW LEVEL JET WILL DEVELOP AHEAD OF THE TROUGH AND LIFT ACROSS LOWER MICHIGAN TOWARDS THE EASTERN GREAT LAKES...ENHANCING MOISTURE CONVERGENCE AND LEADING TO SHOWERS DEVELOPING ACROSS NW OHIO. MODEL SOUNDINGS MOISTEN UP AT TOL BETWEEN 6-9Z SPREADING EAST TOWARDS CLE BY AROUND 12Z. SOUNDINGS ALSO REFLECT SOME MINOR ELEVATED INSTABILITY WHICH COULD SUPPORT ISOLATED THUNDERSTORMS ACROSS NW OHIO OVERNIGHT. POPS TONIGHT WILL RANGE FROM AROUND 80 PERCENT AT TOL TO AROUND 30 PERCENT AT CAK. GIVEN THE INCREASING CLOUD COVER AND SOUTHERLY WINDS NEAR 10 MPH... TEMPERATURES WILL BE MILD FOR EARLY DECEMBER RANGING FROM MID 40S IN NW PA TO THE LOW 50S IN NW OHIO. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... RAIN WILL SPREAD EAST ACROSS THE AREA ON SUNDAY AS SHORTWAVE ENERGY SLIDES ACROSS THE GREAT LAKES REGION AND THE SURFACE LOW MOVES FROM NORTHERN LAKE HURON INTO QUEBEC. A PERIOD OF SHOWERS ARE EXPECTED AT ALL AREAS EVEN THOUGH QPF WILL BE LIGHT...GENERALLY LESS THAN .20 INCH. HAVE SLIGHTLY SPED UP THE TIMING WITH SHOWERS ENDING IN THE TOL AREA BY LATE MORNING. WINDS WILL SHIFT AROUND TO THE SOUTHWEST AS THE TROUGH PASSES BUT THE ACTUAL FRONT WILL STALL OVER LAKE ERIE ON SUNDAY NIGHT WITH NO APPRECIABLE COLD ADVECTION. MID LEVELS DRY OUT QUICKLY LATE IN THE DAY ON SUNDAY BUT PLENTY OF LOW LEVEL MOISTURE WILL REMAIN WITH DEWPOINTS HOVERING NEAR 50 DEGREES. MAV/MET GUIDANCE HIGHLIGHTING LOW CEILINGS AND WITH BACKING LOW LEVEL FLOW HAVE ADDED A CHANCE OF DRIZZLE TO THE FORECAST. TEMPERATURES WILL BE MILD AGAIN IN THE UPPER 40S/LOW 50S. THE STALLED FRONTAL BOUNDARY WILL LIFT NORTH ON MONDAY AS THE UPPER LEVEL RIDGE BUILDS AND SOUTHWESTERLY FLOW INCREASES AGAIN. THERE IS SOME UNCERTAINTY IN HOW FAST WE WILL BE ABLE TO SCOUR OUT THE LOW LEVEL MOISTURE...BUT EXPECTING CLOUDS TO START TO LIFT NORTH AND POSSIBLY SCATTER OUT ACROSS CENTRAL OHIO...WITH SOME SUN SOUTH OF A TOL/CAK LINE. AS LONG AS WE CAN GET SOME BREAKS IN THE CLOUDS...TEMPERATURES SHOULD MAKE A RUN AT THE LOW TO MID 60S. RECORDS ARE STILL SEVERAL DEGREES HIGHER FOR DECEMBER 3RD...RANGING FROM THE UPPER 60S TO MID 70S SO WE WILL LIKELY NOT BE ABLE TO BREAK ANY UNLESS WE END UP WITH FULL SUN ALL DAY. THE NEXT COLD FRONT WILL PUSH SOUTH ACROSS THE AREA ON TUESDAY WITH RAIN ACCOMPANYING THE FRONT. A SECONDARY COLD FRONT WILL ARRIVE LATE TUESDAY NIGHT WITH STRONGER COLD ADVECTION CONTINUING INTO WEDNESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... JUST COLD ENOUGH FOR SOME SNOW FLURRIES/SNOW SHOWERS ON WEDNESDAY IN THE SNOWBELT OTHERWISE HIGH PRESSURE WILL BUILD IN WEDNESDAY AND THURSDAY WITH SEASONABLE TEMPERATURES. THE NEXT COLD FRONT STILL SEEMS ON TRACK FOR FRIDAY. THERE IS A HINT THAT A WEAK WAVE COULD TRY TO FORM ON THE FRONT SOMEWHERE BETWEEN THE GREAT LAKES AND TENNESSEE VALLEY SO NOT REAL CONFIDENT ON THE TIMING AND THEREFORE DID NOT GO REAL HIGH ON THE PROBABILITY OF PRECIPITATION ANY OF THE FORECAST PERIODS. ULTIMATELY WE WILL NEED AT LEAST A LIKELY POP AT SOME POINT LATE IN THE WEEK. IF A WAVE DOES DEVELOP...IT MAY GET COLD ENOUGH FOR A CHANGE TO SNOW ON THE BACK END BUT WILL KEEP IT SIMPLE FOR NOW AND CALL FOR RAIN SHOWERS FRIDAY THEN RAIN AND SNOW SHOWERS FRIDAY NIGHT...AND A SMALL CHANCE OF LINGERING SNOW SHOWERS ON SATURDAY. THE AIR MASS SHOULD BE RELATIVELY WARM ON FRIDAY BUT WILL NOT GO TOO HIGH ON THE FORECAST HIGHS...40S...CONSIDERING THAT THE RAIN WILL PROBABLY DEVELOP ON FRIDAY WHICH WOULD SUPPRESS THE TEMPS. BACK TO SEASONABLE TEMPS ON SATURDAY. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... THE LOW LEVEL JET IS ON THE INCREASE AHEAD OF A WEAKENING COLD FRONT OVERNIGHT. THE SHOWERS ARE BEGINNING TO DEVELOP. THE HRRR MODEL IS NOW DEVELOPING THE SHOWERS A LITTLE SLOWER. WE WILL HAVE SOME SCATTERED SHOWERS AHEAD OF THE MAIN BAND OF SHOWERS. AT THIS TIME NO MENTION OF THUNDER BUT ISOLATED THUNDERSTORMS ARE POSSIBLE LATE TONIGHT THROUGH MID AFTERNOON ON SUNDAY. WINDS WILL BE ON THE INCREASE OVERNIGHT AND THAT SHOULD HELP PREVENT LLWS. MAINLY VFR OVERNIGHT AND THEN SLOWLY DECREASING THE CEILINGS TO IFR ESPECIALLY FOR LATE SUNDAY MORNING AND AFTERNOON...MODERATELY CONFIDENT IN THAT. CONDITIONS WILL STAY IFR ESPECIALLY SOUTH OF THE LAKE SUNDAY EVENING. OUTLOOK...NON VFR LIKELY LATE SUNDAY NIGHT THROUGH TUESDAY. && .MARINE... EVEN THOUGH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE IS SMALL THE SUSTAINED WINDS WILL BE STRONG ENOUGH TO MEET SMALL CRAFT ADVISORY CRITERIA...AN ADVISORY HAS BEEN ISSUED. WILL HAVE TO MONITOR THE WATER LEVEL ON THE WEST END OF THE LAKE ON SUNDAY AS THE WATER LEVEL COULD APPROACH THE CRITICAL MARK FOR SAFE NAVIGATION BUT IT IS NOT EXPECTED TO REACH IT. PREVIOUS DISCUSSION... THE WARM FRONT OVER LAKE ERIE HAS BEEN SLOW TO LIFT NORTH BUT IT SHOULD MOVE NORTH OF THE LAKE EARLY TONIGHT WITH AN INCREASING SOUTH WIND. WINDS ON THE OPEN WATERS MAY APPROACH 30 KNOTS LATE TONIGHT AND SUNDAY MORNING WITH THE HIGHEST WAVES OBVIOUSLY ON THE CANADIAN SIDE OF THE LAKE BUT THE LAKE WILL GET STIRRED UP ENOUGH TO WARRANT A SMALL CRAFT ADVISORY FOR LATER TONIGHT AND SUNDAY. THE GRADIENT WILL WEAKEN ENOUGH FOR THE WIND TO COME DOWN LATER SUNDAY/SUNDAY NIGHT...THEN THE SOUTH TO SOUTHWEST WIND WILL GET REESTABLISHED AND INCREASE AGAIN ON MONDAY AND MONDAY NIGHT AHEAD OF A COLD FRONT ON TUESDAY. THE NORTHWEST FLOW FOLLOWING THE COLD FRONT WILL REMAIN RATHER BRISK WEDNESDAY BEFORE HIGH PRESSURE MOVES OVER THE LAKE AND CALMS THINGS DOWN ON THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR LEZ147>149. SMALL CRAFT ADVISORY UNTIL 3 PM EST SUNDAY FOR LEZ142>146. && $$ SYNOPSIS...KEC NEAR TERM...ABE/KEC SHORT TERM...KEC LONG TERM...KOSARIK AVIATION...KIELTYKA MARINE...KIELTYKA/KOSARIK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1043 AM EST SUN DEC 2 2012 .SYNOPSIS... A WARM FRONT WEDGED ALONG THE EAST-SIDE OF THE ALLEGHENIES WILL LIFT NORTHEAST THROUGH NEW ENGLAND TODAY...AHEAD OF A WEAK FRONTAL SYSTEM PUSHING OUT OF THE GREAT LAKES. THE FRONTAL SYSTEM WILL BE ACCOMPANIED BY A BAND OF RAIN AS IT MOVES THROUGH THE REGION THIS EVENING. ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH EARLY NEXT WEEK BEFORE A COLD FRONT PASSES TUESDAY NIGHT AND BRINGS MORE SHOWERS AND A RETURN TO MORE SEASONAL TEMPERATURES FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 9AM UPDATE... THE FOG ADVISORY HAS BEEN ALLOWED TO EXPIRE AS MOST REPORTING SITES ARE NOW A MILE OR MORE. ELSEWHERE SHOWERS CONTINUE TO PROGRESS SLOWLY OUT OF THE NW MOUNTAINS. HRRR SUGGESTS THE RAIN MAKES ITS BIG PUSH INTO THE CENTRAL PART OF THE STATE AFTER ABOUT MID DAY...BUT OVERALL QPF SHOULD STILL REMAIN MOSTLY ON THE LIGHT SIDE. IT`S BEEN VERY DRY SO ANY RAIN WILL BE WELCOME. VERY MILD AIR HAS SURGED UP WEST OF THE ALLEGHENIES...BUT WHILE WE REMAIN COOL AIR DAMMED...TEMPS ARE STILL MILD FOR THE TIME OF YEAR AND WILL CONTINUE AS SUCH INTO THE NEW WORKWEEK. && .SHORT TERM / MONDAY THROUGH 6 AM MONDAY/... WARM FRONT WEDGED ALONG THE EAST-SIDE OF THE ALLEGHENIES WILL LIFT NWD TDY...ALLOWING A SW FLOW OF UNSEASONABLY MILD AIR TO OVERSPREAD THE ENTIRE AREA. AREAS OF FOG AND LOW STRATUS IN THE CNTRL AND EASTERN ZONES WILL GRADUALLY IMPROVE/LIFT THRU LATE MORNING. A FAST MOVING LOW-AMPLITUDE SHORTWAVE TROUGH OF PACIFIC ORIGIN WILL MOVE FROM THE GREAT LAKES/OH VALLEY INTO THE NERN STATES BY EVENING. STG SWLY LOW LEVEL JET AHEAD OF ITS ASSOC FRONT WILL TRANSPORT ABV NORMAL PWATS ENEWD ACROSS THE UPPER OH VALLEY INTO CENTRAL PA BY THIS AFTN. THIS WILL SUPPORT HI POPS WITH LGT TO MOD PCPN TOTALS EXPECTED. QPF AMTS WILL DROP OFF FROM NW TO SE...AS AREAS EAST OF THE ALLEGHENY FRONT NEVER SEEM TO DO WELL IN TERMS OF QPF WITH SWLY LLVL FLOW DUE TO COMBO OF DOWNSLOPE AND LACK OF LLVL CONVERGENCE. THE BEST MID-UPPER FORCING STAYS TO THE NORTH SO AGAIN NOT LOOKING AT ANY SIGNIFICANT PCPN WITH THIS RATHER WEAK FRONTAL SYSTEM. DESPITE EXTENSIVE CLOUD COVER...THE UNSEASONABLY MILD SWLY FLOW WILL ALLOW TEMPS TO CLIMB 5-10F ABOVE EARLY DECEMBER CLIMATE NORMALS. MAX TEMPS WILL RANGE FROM NR 60F IN THE VALLEYS OF SW AND SC PA...TO AROUND 50F OVR THE HIGH TERRAIN NORTH OF IPT WHERE THE WARM FRONT WILL TAKE THE LONGEST TO CLEAR. THE FRONTAL SYSTEM WILL BECOME DIFFUSE AND ORIENTED FROM WEST-EAST TONIGHT...AS IT DRIFTS SWD AND SETTLES NEAR THE MASON DIXON LINE. DRYING ALOFT AND WSHIFT TO THE WEST WILL RESULT IN DIMINISHING PCPN ACTIVITY WITH JUST SOME PATCHY LIGHT RAIN OR DZ FOR THE OVERNIGHT HOURS. LOWS WILL AGAIN BE FIRMLY ON THE MILD SIDE OF CLIMO. && .LONG TERM /MONDAY THROUGH SATURDAY/... GRADUALLY RISING HEIGHTS AND ZONAL FLOW ALOFT WILL MEAN THAT THE WEAKENING COLD FRONT /SLIDING SOUTHEAST OF THE REGION EARLY MONDAY/ WILL LEAD TO NO REAL TEMP CHANGE THROUGH EARLY IN THE UPCOMING WEEK. IN FACT...THE FLOOD OF PACIFIC AIR /WARMED SIGNIFICANTLY BY DOWNSLOPE IN THE LEE OF THE ROCKIES/ WILL BRING UNSEASONABLY MILD TEMPS IN THE 50S MONDAY...AND 50S/60S FOR TUESDAY. TUESDAY/S HIGHS WILL BE 18-20F ABOVE NORMAL...AND PERHAPS AS MUCH AS 25F ABOVE NORMAL ACROSS LAUREL HIGHLANDS AND ADJACENT SOUTH-CENTRAL VALLEYS. THE POTENT SHORTWAVE CRASHING ONTO THE NW COAST TODAY /SUNDAY/ WILL MOVE QUICKLY EAST ACROSS SOUTHERN CANADA AND AMPLIFY AS IT SLIDES THROUGH ONTARIO PROVINCE DURING THE MIDWEEK PERIOD. THE ASSOCIATED COLD FRONT WILL BRING A SEVERAL HOUR PERIOD OF RAIN SHOWERS TO THE REGION LATE TUESDAY/TUESDAY NIGHT...WITH MOST MODEL GUIDANCE AND ENSEMBLES INDICATING A MEAN QPF OF ABOUT 2-3 TENTHS. THE SURGE OF MUCH COOLER AIR IN THE WAKE OF THE FRONT WILL SUPPORT SCATTERED SNOW SHOWERS ACROSS MAINLY THE MTNS OF NWRN PENN LATE TUESDAY NIGHT AND WEDNESDAY...WITH MINOR ACCUMULATIONS OF A COATING TO AND INCH OR TWO POSSIBLE /NEAR AND TO THE WEST OF KBFD/. ENSEMBLE MOS TEMPS STAY A FEW...TO SEVERAL DEG F ABOVE NORMAL FOR THURSDAY AND FRIDAY AS UPPER HEIGHTS REBOUND ONLY SLIGHTLY...AND A BUBBLE OF HIGH PRESSURE WITH CP AIR SLIDES SE FROM THE PRAIRIE PROVINCES OF SCENT CANADA AND REACHES THE NE U.S. COAST THURSDAY NIGHT. UNCERTAINTY CLIMBS SIGNIFICANTLY FOR NEXT WEEKEND AS THE NEXT COLD FRONTAL BOUNDARY SLOWS AND PERHAPS TEMPORARILY STALLS OUT FROM THE OHIO VALLEY THROUGH THE MID ATLANTIC REGION. LARGE DIVERGENCE ARISES IN THE QPF PATTERN/FRONTAL LOCATION BETWEEN 00Z/06Z GFS AND EC...ALONG WITH A LARGE SPREAD IN GEFS /PLUME/ QPF AND SFC-925 MB TEMPS. RAIN CHANCES INCREASE BEGINNING LATE FRIDAY NIGHT THROUGH NEXT WEEKEND...AND COULD POSSIBLY BE MIXED WITH SNOW ACROSS THE NW HALF OF THE STATE. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... 10AM UPDATE... WIDESPREAD LOW CLOUDS AND FOG CONTINUE TO AFFECT MOST OF MY CENTRAL AND EASTERN TERMINALS. MEANWHILE RAIN IS MOVING INTO MY NWRN FCST AREA BRING REDUCED CONDITIONS THERE. ONLY SITE WITH NO PROBLEMS AS OF 10AM IS JST WHICH HAS BROKEN OUT INTO THE WARM AIR AND CURRENTLY IS REPORTING CLEAR SKIES AND UNLIMITED VIZ. THE AREAS AFFECTED BY THE LOW CLOUDS AND FOG WILL SEE ONLY GRADUAL IMPROVEMENT TODAY AS MOST OF THE REGION REMAINS COLD AIR DAMMED AND MIXING IS LIMITED. MEANWHILE A MORE GENERAL LIGHT RAIN WILL OVERSPREAD THE FCST AREA AFTER MID DAY...SO PROSPECTS FOR SIGNIFICANT IMPROVEMENT DO NOT LOOK PROMISING. A WEAK FRONTAL SYSTEM CROSSING THE GREAT LAKES WILL MOVE THROUGH THE AIRSPACE THIS EVE AND EARLY TNT...ACCOMPANIED BY RAIN AND WIDESPREAD MVFR/IFR. REDUCED CIGS AND VSBYS SHOULD PREVAIL OVR THE WRN SITES EVEN BEHIND THE FRONT...WITH WEAK UPSLOPE PRODUCING AREAS OF -RA/DZ. DOWNSLOPE FLOW EAST OF THE MTNS SHOULD ALLOW MVFR THRU THE END OF THE PD. OUTLOOK... MON...MORNING MVFR/IFR...BECMG VFR DURING THE AFTERNOON. TUE...VFR TO MVFR WITH RAIN SHOWERS. ISOLD TSTMS PSBL. WSHFT. WED...MVFR WEST WITH SNOW/RAIN SHOWERS. THU...NO SIG WX. && .CLIMATE... NOVEMBER 2012 WAS A COLD AND DRY MONTH AT BOTH OFFICIAL CLIMATE SITES. IT WAS AN EXCEPTIONALLY DRY MONTH AT WILLIAMSPORT. AT WILLIAMSPORT...THE AVERAGE MONTHLY TEMPERATURE OF 39.6 DEGREES TIED 1971 AS THE 25TH COLDEST NOVEMBER ON RECORD. THE TOTAL MONTHLY PRECIPITATION OF 0.65 INCHES RANKED AS THE 5TH DRIEST NOVEMBER ON RECORD. THE TOP 5 DRIEST NOVEMBER`S AT WILLIAMSPORT ARE: 1. 1904 - 0.51 INCHES 2. 1917 - 0.53 INCHES 3. 1908 - 0.56 INCHES 4. 1909 - 0.59 INCHES 5. 2012 - 0.65 INCHES AT HARRISBURG...THE AVERAGE MONTHLY TEMPERATURE OF 40.7 DEGREES RANKED AS THE 16TH COLDEST NOVEMBER ON RECORD. THE TOTAL MONTHLY PRECIPITATION OF 1.05 INCHES RANKED AS THE 19TH DRIEST NOVEMBER ON RECORD. NO DAILY RECORDS WERE SET AT EITHER SITE DURING NOVEMBER 2012. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT HARRISBURG SINCE 1888...AND SINCE 1895 AT WILLIAMSPORT. SEE PHLCLSIPT AND PHLCLSMDT FOR THE FALL SEASONAL SUMMARIES AT WILLIAMSPORT AND HARRISBURG. THESE CAN BE FOUND AT WEATHER.GOV/CTP. && .EQUIPMENT... IPT OBSERVATION NOT BEING TRANSMITTED OR RECEIVED INTO OUR SYSTEMS. FAA IS AWARE AND WORKING THE ISSUE. WE STILL HAVE DIAL-UP CAPABILITY. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/STEINBUGL NEAR TERM...LA CORTE/STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LAMBERT AVIATION...LA CORTE/STEINBUGL CLIMATE...LA CORTE EQUIPMENT...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
930 AM EST SUN DEC 2 2012 .SYNOPSIS... A WARM FRONT WEDGED ALONG THE EAST-SIDE OF THE ALLEGHENIES WILL LIFT NORTHEAST THROUGH NEW ENGLAND TODAY...AHEAD OF A WEAK FRONTAL SYSTEM PUSHING OUT OF THE GREAT LAKES. THE FRONTAL SYSTEM WILL BE ACCOMPANIED BY A BAND OF RAIN AS IT MOVES THROUGH THE REGION THIS EVENING. ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH EARLY NEXT WEEK BEFORE A COLD FRONT PASSES TUESDAY NIGHT AND BRINGS MORE SHOWERS AND A RETURN TO MORE SEASONAL TEMPERATURES FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 9AM UPDATE... THE FOG ADVISORY HAS BEEN ALLOWED TO EXPIRE AS MOST REPORTING SITES ARE NOW A MILE OR MORE. ELSEWHERE SHOWERS CONTINUE TO PROGRESS SLOWLY OUT OF THE NW MOUNTAINS. HRRR SUGGESTS THE RAIN MAKES ITS BIG PUSH INTO THE CENTRAL PART OF THE STATE AFTER ABOUT MID DAY...BUT OVERALL QPF SHOULD STILL REMAIN MOSTLY ON THE LIGHT SIDE. IT`S BEEN VERY DRY SO ANY RAIN WILL BE WELCOME. VERY MILD AIR HAS SURGED UP WEST OF THE ALLEGHENIES...BUT WHILE WE REMAIN COOL AIR DAMMED...TEMPS ARE STILL MILD FOR THE TIME OF YEAR AND WILL CONTINUE AS SUCH INTO THE NEW WORKWEEK. && .SHORT TERM / MONDAY THROUGH 6 AM MONDAY/... WARM FRONT WEDGED ALONG THE EAST-SIDE OF THE ALLEGHENIES WILL LIFT NWD TDY...ALLOWING A SW FLOW OF UNSEASONABLY MILD AIR TO OVERSPREAD THE ENTIRE AREA. AREAS OF FOG AND LOW STRATUS IN THE CNTRL AND EASTERN ZONES WILL GRADUALLY IMPROVE/LIFT THRU LATE MORNING. A FAST MOVING LOW-AMPLITUDE SHORTWAVE TROUGH OF PACIFIC ORIGIN WILL MOVE FROM THE GREAT LAKES/OH VALLEY INTO THE NERN STATES BY EVENING. STG SWLY LOW LEVEL JET AHEAD OF ITS ASSOC FRONT WILL TRANSPORT ABV NORMAL PWATS ENEWD ACROSS THE UPPER OH VALLEY INTO CENTRAL PA BY THIS AFTN. THIS WILL SUPPORT HI POPS WITH LGT TO MOD PCPN TOTALS EXPECTED. QPF AMTS WILL DROP OFF FROM NW TO SE...AS AREAS EAST OF THE ALLEGHENY FRONT NEVER SEEM TO DO WELL IN TERMS OF QPF WITH SWLY LLVL FLOW DUE TO COMBO OF DOWNSLOPE AND LACK OF LLVL CONVERGENCE. THE BEST MID-UPPER FORCING STAYS TO THE NORTH SO AGAIN NOT LOOKING AT ANY SIGNIFICANT PCPN WITH THIS RATHER WEAK FRONTAL SYSTEM. DESPITE EXTENSIVE CLOUD COVER...THE UNSEASONABLY MILD SWLY FLOW WILL ALLOW TEMPS TO CLIMB 5-10F ABOVE EARLY DECEMBER CLIMATE NORMALS. MAX TEMPS WILL RANGE FROM NR 60F IN THE VALLEYS OF SW AND SC PA...TO AROUND 50F OVR THE HIGH TERRAIN NORTH OF IPT WHERE THE WARM FRONT WILL TAKE THE LONGEST TO CLEAR. THE FRONTAL SYSTEM WILL BECOME DIFFUSE AND ORIENTED FROM WEST-EAST TONIGHT...AS IT DRIFTS SWD AND SETTLES NEAR THE MASON DIXON LINE. DRYING ALOFT AND WSHIFT TO THE WEST WILL RESULT IN DIMINISHING PCPN ACTIVITY WITH JUST SOME PATCHY LIGHT RAIN OR DZ FOR THE OVERNIGHT HOURS. LOWS WILL AGAIN BE FIRMLY ON THE MILD SIDE OF CLIMO. && .LONG TERM /MONDAY THROUGH SATURDAY/... GRADUALLY RISING HEIGHTS AND ZONAL FLOW ALOFT WILL MEAN THAT THE WEAKENING COLD FRONT /SLIDING SOUTHEAST OF THE REGION EARLY MONDAY/ WILL LEAD TO NO REAL TEMP CHANGE THROUGH EARLY IN THE UPCOMING WEEK. IN FACT...THE FLOOD OF PACIFIC AIR /WARMED SIGNIFICANTLY BY DOWNSLOPE IN THE LEE OF THE ROCKIES/ WILL BRING UNSEASONABLY MILD TEMPS IN THE 50S MONDAY...AND 50S/60S FOR TUESDAY. TUESDAY/S HIGHS WILL BE 18-20F ABOVE NORMAL...AND PERHAPS AS MUCH AS 25F ABOVE NORMAL ACROSS LAUREL HIGHLANDS AND ADJACENT SOUTH-CENTRAL VALLEYS. THE POTENT SHORTWAVE CRASHING ONTO THE NW COAST TODAY /SUNDAY/ WILL MOVE QUICKLY EAST ACROSS SOUTHERN CANADA AND AMPLIFY AS IT SLIDES THROUGH ONTARIO PROVINCE DURING THE MIDWEEK PERIOD. THE ASSOCIATED COLD FRONT WILL BRING A SEVERAL HOUR PERIOD OF RAIN SHOWERS TO THE REGION LATE TUESDAY/TUESDAY NIGHT...WITH MOST MODEL GUIDANCE AND ENSEMBLES INDICATING A MEAN QPF OF ABOUT 2-3 TENTHS. THE SURGE OF MUCH COOLER AIR IN THE WAKE OF THE FRONT WILL SUPPORT SCATTERED SNOW SHOWERS ACROSS MAINLY THE MTNS OF NWRN PENN LATE TUESDAY NIGHT AND WEDNESDAY...WITH MINOR ACCUMULATIONS OF A COATING TO AND INCH OR TWO POSSIBLE /NEAR AND TO THE WEST OF KBFD/. ENSEMBLE MOS TEMPS STAY A FEW...TO SEVERAL DEG F ABOVE NORMAL FOR THURSDAY AND FRIDAY AS UPPER HEIGHTS REBOUND ONLY SLIGHTLY...AND A BUBBLE OF HIGH PRESSURE WITH CP AIR SLIDES SE FROM THE PRAIRIE PROVINCES OF SCENT CANADA AND REACHES THE NE U.S. COAST THURSDAY NIGHT. UNCERTAINTY CLIMBS SIGNIFICANTLY FOR NEXT WEEKEND AS THE NEXT COLD FRONTAL BOUNDARY SLOWS AND PERHAPS TEMPORARILY STALLS OUT FROM THE OHIO VALLEY THROUGH THE MID ATLANTIC REGION. LARGE DIVERGENCE ARISES IN THE QPF PATTERN/FRONTAL LOCATION BETWEEN 00Z/06Z GFS AND EC...ALONG WITH A LARGE SPREAD IN GEFS /PLUME/ QPF AND SFC-925 MB TEMPS. RAIN CHANCES INCREASE BEGINNING LATE FRIDAY NIGHT THROUGH NEXT WEEKEND...AND COULD POSSIBLY BE MIXED WITH SNOW ACROSS THE NW HALF OF THE STATE. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... 02/12Z - 03/12Z... WDSPRD FOG AND LOW STRATUS COVERS CENTRAL AND ERN TAF SITES...AS RELATIVELY MOIST SE FLOW INTERSECTS WARM FRONT WEDGED ALONG THE EAST-SIDE OF THE ALLEGHENIES. HIGH CONFIDENCE IN IFR-LIFR CONDS AT MDT/LNS WITH CIGS/VIS BLW AIRFIELD MINS AT TIMES. MVFR-IFR CONDS EXPECTED AT IPT/UNV/AOO...WITH VFR IN THE WARM SECTOR/WEST OF THE WARM FRONT AT JST/BFD. STG SSWLY LLJ WILL PRODUCE A PERIOD OF LLWS FROM MID-MORNING THRU LATE AFTN. ANTICIPATE SOME IMPROVEMENT OVR ERN SXNS BY THE EARLY AFTN AS WARM FRONT LIFTS NWD INTO NEW ENGLAND...AND WINDS CONTINUE TO VEER/TURN MORE TO THE SOUTH-SOUTHWEST. FRONTAL SYSTEM CROSSING THE GREAT LAKES WILL MOVE THROUGH THE AIRSPACE THIS EVE AND EARLY TNT...ACCOMPANIED BY A BAND OF LGT-MOD RAIN. REDUCED CIGS AND VSBYS SHOULD PREVAIL OVR THE WRN SITES BEHIND THE FRONT...WITH WEAK UPSLOPE PRODUCING IFR CIGS AND AREAS OF -RA/DZ. DOWNSLOPE FLOW EAST OF THE MTNS SHOULD ALLOW MVFR THRU THE END OF THE PD. OUTLOOK... MON...MVFR/IFR CIGS LKLY WEST. TUE...VFR TO MVFR WITH RAIN SHOWERS. ISOLD TSTMS PSBL. WSHFT. WED...MVFR WEST WITH SNOW/RAIN SHOWERS. THU...NO SIG WX. && .CLIMATE... NOVEMBER 2012 WAS A COLD AND DRY MONTH AT BOTH OFFICIAL CLIMATE SITES. IT WAS AN EXCEPTIONALLY DRY MONTH AT WILLIAMSPORT. AT WILLIAMSPORT...THE AVERAGE MONTHLY TEMPERATURE OF 39.6 DEGREES TIED 1971 AS THE 25TH COLDEST NOVEMBER ON RECORD. THE TOTAL MONTHLY PRECIPITATION OF 0.65 INCHES RANKED AS THE 5TH DRIEST NOVEMBER ON RECORD. THE TOP 5 DRIEST NOVEMBER`S AT WILLIAMSPORT ARE: 1. 1904 - 0.51 INCHES 2. 1917 - 0.53 INCHES 3. 1908 - 0.56 INCHES 4. 1909 - 0.59 INCHES 5. 2012 - 0.65 INCHES AT HARRISBURG...THE AVERAGE MONTHLY TEMPERATURE OF 40.7 DEGREES RANKED AS THE 16TH COLDEST NOVEMBER ON RECORD. THE TOTAL MONTHLY PRECIPITATION OF 1.05 INCHES RANKED AS THE 19TH DRIEST NOVEMBER ON RECORD. NO DAILY RECORDS WERE SET AT EITHER SITE DURING NOVEMBER 2012. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT HARRISBURG SINCE 1888...AND SINCE 1895 AT WILLIAMSPORT. SEE PHLCLSIPT AND PHLCLSMDT FOR THE FALL SEASONAL SUMMARIES AT WILLIAMSPORT AND HARRISBURG. THESE CAN BE FOUND AT WEATHER.GOV/CTP. && .EQUIPMENT... IPT OBSERVATION NOT BEING TRANSMITTED OR RECEIVED INTO OUR SYSTEMS. FAA IS AWARE AND WORKING THE ISSUE. WE STILL HAVE DIAL-UP CAPABILITY. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/STEINBUGL NEAR TERM...LA CORTE/STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LAMBERT AVIATION...STEINBUGL CLIMATE...LA CORTE EQUIPMENT...LA CORTE
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
347 PM EST SUN DEC 2 2012 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE REGION THROUGH MONDAY. A COLD FRONT WILL THEN CROSS THE CAROLINAS AND NORTHEAST GEORGIA LATE TUESDAY INTO WEDNESDAY. IN THE FRONTS WAKE...CANADIAN HIGH PRESSURE WILL RETURN FOR THE LATTER PORTION OF THE WORK WEEK. && .NEAR TERM /THROUGH MONDAY/... 330 PM UPDATE...NO SIGNIFICANT CHANGES TO FCST. TOUCHED UP TEMPS AND SKY COVER PER LATEST OBS BUT EVENING TRENDS LOOK FINE. UPPER LEVEL SHORT WAVE TROUGH MOVING ACROSS THE EASTERN GREAT LAKES INTO NEW ENGLAND LATE THIS AFTERNOON AND THIS EVENING WILL PUSH THE ASSOCIATED SURFACE COLD FRONT INTO THE EASTERN GREAT LAKES AND NORTHERN MID-ATLANTIC REGION BY MORNING. THE FRONTAL CLOUDS AND THE CLOUDS PRODUCED BY PRE-FRONTAL CONVECTION WILL EDGE INTO THE FORECAST AREA DURING THE NIGHT. DO NOT EXPECT ANY PRECIPITATION WITH THIS CLOUD BAND... BUT IT COULD DIMINISH AN OTHERWISE FAVORABLE SETUP FOR MORNING FOG... AND POSSIBLY SOME STRATUS... BY DECREASING RADIATIONAL COOLING AND WEAKENING THE BOUNDARY LAYER INVERSION. DURING MONDAY... AS THE SHORT WAVE TROUGH MOVES FROM NEW ENGLAND INTO THE ATLANTIC PROVINCES... THE UPPER LEVEL RIDGE OVER THE EASTERN STATES WILL INCREASE IN AMPLITUDE AND MAINTAIN SURFACE HIGH PRESSURE ACROSS THE SOUTHEAST. THE FORECAST AREA WILL REMAIN IN THE WARM SECTOR DURING MONDAY AS THE FRONT TO OUR NORTH DRIFTS TO THE NORTH AND THE NEXT COLD FRONT IS STILL SOME DISTANCE TO THE WEST. TEMPERATURES TONIGHT AND MONDAY ARE EXPECTED TO REMAIN QUITE A BIT ABOVE NORMAL. THE LOWS MONDAY MORNING... NEAR 40 IN MOUNTAIN VALLEYS AND UPPER 40S TO AROUND 50 ELSEWHERE... WILL BE ABOUT TEN DEGREES ABOVE NORMAL. HIGH TEMPERATURES ON MONDAY... MID AND UPPER 60S IN MOUNTAIN VALLEYS AND NEAR 70 OUTSIDE THE MOUNTAINS... WILL BE TEN TO FIFTEEN DEGREES ABOVE NORMAL. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 200 PM EST SUNDAY...HEIGHTS WILL DECREASE OVER THE REGION BY MONDAY NIGHT AS A SHORT WAVE RIDGE AXIS MOVES OFF THE EAST COAST AND A POSITIVELY TILTED UPPER TROUGH TRANSLATE EAST ACROSS THE MISSISSIPPI VALLEY. THE UPPER TROUGH IS EXPECTED TO SWING ACROSS OUR CWA LATE TUESDAY NIGHT INTO WED AFTERNOON AND MOVE OFFSHORE BY WED NIGHT. AT THE SURFACE...THE RIDGE OF HIGH PRESSURE WILL WEAKEN AND GRADUALLY MOVE OFF THE EAST COAST ON TUESDAY AS A SURFACE COLD FRONT APPROACHES FROM THE WEST. EXPECT INCREASING CLOUD COVER AND WARMER TEMPERATURES OVER THE REGION AS THE LLVL SOUTHWESTERLY WINDS INCREASE AHEAD OF THE FRONT. TEMPERATURES WILL BE AROUND 10 DEGREES ABOVE NORMAL WITH AFTERNOON HIGHS WARMING INTO THE LOW 70S OVER THE PIEDMONT AND 60S IN THE MOUNTAINS/VALLEYS. THE COLD FRONT WILL MOVE INTO THE APPALACHIANS BY 12Z WED AND CROSSES OUR CWA THROUGH 18Z WED. MODELS HAVE TRENDED A BIT WETTER AND SLOWER WITH THE FROPA BUT STILL LOOKING UNIMPRESSIVE WITH REGARD TO UPPER FORCING AND MOISTURE AVAILABILITY WITH THE SYSTEM. THE BEST UPPER FORCING WILL MOVE WELL TO OUR NORTH AND THE PRECIP AMOUNTS DECREASE ALONG THE FRONT AS IT PUSHES ACROSS OUR CWA. THE LATEST NAM AND THE GFS SHOW A BIT OF CAPE VALUES...UP TO 200J/KG MAINLY OVER OUR SOUTHERN SECTIONS ON WED AFTERNOON. BUT DUE TO WEAK WIND SHEAR ALOFT...SHOULD NOT SUPPORT SEVER WEATHER AT THIS TIME. POPS HAVE BEEN ADJUSTED ACCORDINGLY AND SHOULD TAPER OFF BY WED AFTERNOON. TEMPERATURES WILL BE AROUND 3-5 DEGREES ABOVE NORMAL ON WEDNESDAY && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 2 PM SUNDAY...THE FIRST PART OF THE MEDIUM RANGE STILL LOOKS FAIRLY QUIET...BUT THE SITUATION MAY GET MORE ACTIVE TOWARD THE END OF THE PERIOD. AFTER SOME LINGERING SLIGHT CHC OF PRECIP ON THE BACK SIDE OF THE FRONT WEDNESDAY EVE...EXPECT SOME DRYING FOR THURSDAY AND THURSDAY NIGHT WITH A FLAT UPPER PATTERN AND SURFACE HIGH PRESSURE RIDGING DOWN FROM THE N. THIS MAY BE SHORT LIVED... THOUGH...AS THE MODELS SUGGEST MOISTURE RETURN AS EARLY AS LATE THURSDAY NIGHT. IT HELPS THAT THE FRONT NEVER MAKES IT VERY FAR TO OUR SOUTH DURING MIDWEEK. AT ANY RATE...LOW LEVEL MOISTURE WILL BE ON HAND FOR FRIDAY AND SATURDAY WITH THE MODELS SHOWING A PROLONGED SW FLOW FROM THE GULF. A FEW WEAK UPPER WAVES WILL PASS THROUGH ON FRIDAY AND SATURDAY WHICH WILL ENHANCE THE POSSIBILITY OF SOME SHOWER ACTIVITY. THE GUIDANCE POP WAS ACCEPTED FOR THIS FCST EVEN THOUGH CONFIDENCE IS BETTER THAT MOST LOCATIONS WILL REMAIN DRY FOR THE EARLY PART OF THE WEEKEND. THE MODELS DIVERGE LATE IN THE PERIOD WITH THE TIMING AND AMPLITUDE OF AN UPPER TROF OVER THE PLAINS. THE FCST SPLITS THE DIFFERENCE BETWEEN THE FASTER 00Z RUN OF THE ECMWF...WHICH WOULD BRING THE NEXT MORE SIGNIFICANT COLD FRONT INTO THE MTNS BY SUNSET SUNDAY...AND THE SLOWER GFS WHICH LAGS IT BACK ACROSS THE MS VALLEY. A CHANCE POP WAS MAINTAINED ACROSS THE ENTIRE FCST AREA FOR THE SATURDAY NIGHT AND SUNDAY TIME FRAME. TEMPS SHOULD STAY ABOVE NORMAL. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... 21Z UPDATE...FOR KCLT...CURRENT TAF MAINTAINS GUST POTENTIAL TO 23Z AND THAT TIMING SEEMS APPROPRIATE GIVEN RAP SOUNDINGS AND KGSP VAD WIND PROFILE SHOWING 15KT WINDS NEAR TOP OF MIXED LAYER. CLOUDS ARE NOT LIKELY TO FURTHER DEVELOP OR FORM A CIG THIS AFTN. DID ALSO UPDATE KAVL TAF TO INCLUDE SOME LOW END GUSTS THIS AFTN FOR SIMILAR REASONS...THOUGH GUSTS SHOULD BECOME LESS FREQUENT AS WE APPROACH SUNSET. AT KCLT... BROKEN TO SCATTERED CLOUDS 3-5K FT WILL CONTINUE THIS AFTERNOON AND VISIBILITY WILL BE UNRESTRICTED. HIGH PRESSURE SYSTEM EXTENDING INTO THE AREA FROM THE NORTHEAST WILL PRODUCT A SOUTHWEST WIND AROUND 10 KT. OVERNIGHT... SCATTERED CLOUDS AROUND 3K FT WILL PERSIST. AFTER 08Z VISIBILITY AROUND 5 MILES IN FOG WILL DEVELOP. CONDENSATION PRESSURE DEFICITS AND BOUNDARY LAYER INVERSION TOWARD DAYBREAK CREATE FAVORABLE CONDITIONS FOR FOG... BUT HIGHER CLOUDS JUST TO THE NORTH OF THE TERMINAL COULD EDGE INTO THE AREA THUS DIMINISHING RADATIONAL COOLING AND THE MOST FAVORABLE SETUP FOR FOG. AFTER 14Z... VISIBILITY WILL BECOME UNRESTRICTED WITH SCATTERED CLOUD NEAR 4K FT. WIND WILL BE SOUTHWEST NEAR 10 KT. REMAINDER TERMINALS... BROKEN TO SCATTERED CLOUDS 3-5 KT FT WILL CONTINUE THIS AFTERNOON AND INTO THE EVENING WITH VISIBILITY UNRESTRICTED. AFTER 06Z... AREAS OF FOG 3-5 MILES WILL DEVELOP DUE TO FAVORABLE CONDENSATION PRESSURE DEFICITS AND BOUNDARY LAYER INVERSION. VISIBILITY VICINITY KAVL LIKELY TO LOWER TO AROUND 1 MILE IN FOG BY 10Z. IF HIGHER CLOUDS JUST TO THE NORTH OF THE FORECAST AREA MOVE FURTHER SOUTH THAN EXPECTED OVERNIGHT... SURFACE COOLING WILL BE DIMINISHED SOMEWHAT AND FOG WILL BE LESS LIKELY. VISIBILITY WILL BECOME UNRESTRICTED AFTER 14Z. OUTLOOK...LOW LEVEL MOISTURE MAY CREATE RESTRICTIONS AGAIN TUESDAY MORNING. A COLD FRONT IS EXPECTED TO CROSS THE REGION TUESDAY NIGHT AND EARLY WEDNESDAY...WITH DRY HIGH PRESSURE RETURNING MID TO LATE WEEK. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JPT NEAR TERM...LGL/WIMBERLEY SHORT TERM...JOH LONG TERM...PM AVIATION...LGL/WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1001 AM EST SUN DEC 2 2012 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE SOUTHEAST BRINGING DRY CONDITIONS THROUGH MONDAY. A COLD FRONT WILL CROSS THE CAROLINAS AND NORTHEAST GEORGIA LATE TUESDAY INTO WEDNESDAY...BEFORE CANADIAN HIGH PRESSURE RETURNS LATER IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AT 930 AM... WEB CAMS SHOW A LITTLE BIT OF FOG PERSISTING IN SOME OF THE MOUNTAIN VALLEYS. HIGHER CLOUD IS LIKELY SLOWING THE DISSIPATION PROCESS A LITTLE BIT BY CUTTING DOWN ON SURFACE WARMING AND SUBSEQUENT MIXING. WILL CARRY FOG FOR A COUPLE OF HOURS... BUT REMAINDER FORECAST VIRTUALLY UNCHANGED EXCEPT FOR UPDATING TEMPERATURES AND DEWPOINTS FOR CURRENT CONDITIONS. AS OF 630 AM...LATEST RADAR IMAGES INDICATE THAT LIGHT SHRA TO SPRINKLES EXTENDED ALONG THE HIGH TERRAIN ALONG THE NC/SC/GA BORDER NE TO THE NC FOOTHILLS. I WILL UPDATE THE FORECAST TO ADJUST POPS. IN ADDITION...WIDESPREAD HIGH CLOUDS HAS RESULTED IN LESS FOG THAN PREVIOUSLY EXPECTED...I WILL REDUCE FOG MENTION FOR THE UPDATE. AS OF 230 AM...LATEST IMAGES FROM THE KGSP RADAR INDICATED A FEW SHOWERS ACROSS THE FOOTHILLS AND MTNS OF NE GA AND SC. THESE SHOWERS ARE LIKELY SUPPORTED BY UPSLOPE FLOW AND 290K ISENTROPIC LIFT. THE 0Z NAM INDICATES THAT LLVL LIFT MAY INCREASE THROUGH SUNRISE...THEN WILL GRADUALLY WEAKEN AS LLVL WIND VEER WEST. I WILL INDICATE AN AREA OF INCREASING SCHC POPS ACROSS THE NRN SC UPSTATE AND NE GA THROUGH SUNRISE...THE COVERAGE WILL FADE BY MID DAY. SIMILARLY...I EXPECT THAT CLOUD COVER WILL INCREASE THROUGH DAYBREAK...THEN CLOUD COVER SHOULD SLOWLY DECREASE FROM WEST TO EAST THROUGH THE REST OF THE DAY. SW WINDS SHOULD INCREASE LLVL THICKNESSES AND TEMPERATURE PROFILES THROUGH THIS AFTERNOON. MOS CONSENSUS SUPPORT HIGH TEMPERATURES AROUND 10 DEGREES ABOVE NORMAL. TONIGHT...A WEAK COLD FRONT IS EXPECTED TO MOVE ACROSS THE CENTRAL APPALACHIANS AND BECOME NEARLY STATIONARY BY 12Z MON. THE BOUNDARY IS EXPECTED TO REMAIN NORTH OF THE CWA...LEAVING THE FORECAST AREA IN THE WARM SECTOR. IN ADDITION...CLOUD COVER ASSOCIATED WITH THE BORDER WILL LIKELY RESULT IN INCREASE COVERAGE ACROSS THE MTNS AND NC FOOTHILLS AND PIEDMONT. MIN TEMPERATURES WILL LIKELY REMAIN AROUND 10 DEGREES ABOVE NORMAL GIVEN THE LINGERING WARM LLVL PROFILES AND CLOUD COVER. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 205 AM EST SUNDAY...A SHORT WAVE RIDGE WILL BUILD ACROSS THE REGION DURING THE DAY ON MONDAY. AT THE SFC THE LLVL FLOW WILL TURN OUT OF THE WEST EARLY IN THE DAY. THE DOWNSLOPE FLOW AND GENERALLY LIGHT BNDRY LAYER WIND SPEEDS SHOULD LIMIT LOW AND MID LEVEL CLOUD COVER WITH THE BALANCE OF THE DAY EXPECTED TO BE MOSTLY SUNNY. H8 TEMPS WILL INCREASE TO AROUND 9 DEG C WHICH SHOULD SUPPORT HIGH TEMPS 10 TO 12 DEGREES ABOVE NORMAL. THE ZONAL FLOW WILL BUCKLE A LITTLE ACROSS THE CENTRAL STATES ON TUESDAY. HOWEVER...THE MODELS CONTINUE TO HAVE A BROAD...TRANSITORY AND RATHER WEAK TROUGH. THE UP SIDE OF THIS THIS THAT THERE WILL BE NO SEVERE WEATHER THREAT WITH THE TROUGH. THE DOWN SIDE IS THAT THE LOW AMPLITUDE WILL SUPPORT LITTLE IN THE WAY OF RETURN FLOW AND THE FRONTAL BAND SHOULD WEAKEN AS IT ENTERS THE MOUNTAINS LATE TUE NIGHT. ALONG THE TN LINE A QUARTER TO A HALF INCH OF RAIN IS POSSIBLE...BUT AMOUNTS FARTHER TO THE EAST APPEAR AT THIS TIME AS IF THEY WILL BE SIGNIFICNATLY LIGHTER. I DID BUMP POPS UP INTO THE LIKELY RANGE ALONG THE TN LINE LATE TUE NIGHT...IN LINE WITH THE SREF 3 HOURLY POPS. AS FOR HIGH TEMPS DURING THE DAY ON TUESDAY...THEY SHOULD BE AS WARM OR WARMER AS MONDAY/S HIGHS... WARMING INTO THE LOWER 70S OUTSIDE THE MTNS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 250 AM SUNDAY...NO NEED TO MAKE ANY SIGFNT CHANGES TO THE EXT RANGE FCST. THE OP MODELS ARE IN GOOD AGREEMENT...AT LEAST THROUGH THE FIRST HALF OF THE PERIOD. A CONTINUED EASTWARD PROGRESSION OF THE UPPER WAVE IS ANTICIPATED WITH LITTLE DYNAMICAL RESPONSE AS SFC BASED LAYERED SHEAR WILL REMAIN LOW. THE SFC FRONT WILL BE WEAKENING AS IT MOVES EAST OF THE AREA WITH LESS AND LESS UPPER SUPPORT. THE GFS IS STILL QUICKER WITH A FROPA WHILE THE ECWMF INDICATES A BETTER CHANCE OF INSTABILITY DEVELOPING OVER THE SRN MOST ZONES. THIS IDEA IS STILL NOT SUPPORTED BY ANY OTHER MODEL NOR STATISTICAL GUIDANCE...SO ANY MENTION THUNDER WILL REMAIN OUT OF THE FCST. MOST OF THE FRONTAL PRECIP WILL FALL ACROSS THE NC MTNS EARLIER AND LINGERING QPF AMOUNTS WILL BE 0.25 OR LESS...UNLESS SOME DEEPER CONVECTION ACTUALLY MATERIALIZES DURING THE AFTERNOON. ANOTHER CP SFC HIGH BUILDS IN QUICKLY THU AND THIS WILL HOLD MAX TEMPS DOWN FROM WED/S HIGHS BY ABOUT 8-10 DEGREES OR RIGHT AROUND NORMAL. TEMPS WILL SLOWLY MODIFY A COUPLE DEGREES FRI IN GOOD INSOLATION. IT LOOKS PROBABLE THAT A NRN GOM SYSTEM WILL MOVE UP THE TN VALLEY THROUGH SAT AND INCREASING CLOUD COVER WILL HOLD TEMPS IN CHECK...SIMILAR TO FRI/S HIGHS. THE GOING POPS FOR LATE FRI INTO SAT LOOK GOOD WITH THE WRN MOST ZONES RECEIVING A LOW END CHANCE MENTION AND ISOL ELSEWHERE. LOW END DYNAMICS AND A CONTINUED STABLE AIRMASS WILL OFFSET ANY THUNDER MENTION ONCE AGAIN. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... AT KCLT... LATEST RAP INDICATES CLOUD LAYER NEAR 7K FT WILL DISSIPATE AROUND 18Z OR SHORTLY THEREAFTER BUT LOWER SCATTERED TO BROKEN DECK CORRESPONDING TO CURRENT 4K FT LAYER WILL PERSIST. LATE MORNING TAF UPDATED WILL REFLECT THIS TREND WHICH IS SIMILAR TO CURRENT FORECAST. VERY LIGHT SURFACE PRESSURE GRADIENT SHOULD KEEP SOUTHWEST WIND SPEEDS LESS THAN 10 KT. NO SIGNIFICANT WEATHER AFTER 00Z UNTIL POSSIBILITY OF LOW STRATUS AND FOG INCREASES. THE NAM FORECAST SOUNDINGS INDICATE A STRONG BL INVERSION LATE TONIGHT. CONDENSATION PRESSURE DEFICITS FALL TO NEAR 0 MBS ACROSS MOST OF THE PIEDMONT BY 12Z MON. IT APPEARS THAT CONDITIONS WILL FAVOR IFR CEILINGS AND FOG MONDAY MORNING. ELSEWHERE...CONDITIONS WILL REMAIN VFR ACROSS THE WESTERN CAROLINAS THIS AFTERNOON. SOUTHWEST WINDS WILL STRENGTHEN TO 5 TO 7 KTS...BUT DECREASING TO 3 KTS AFTER SUNSET. CLOUD COVER MAY DECREASE LATE TONIGHT AS LLVL WIND FIELDS VEER SW. THE NAM FORECAST SOUNDINGS INDICATE A STRONG BL INVERSION LATE TONIGHT ACROSS THE PIEDMONT...LESS DEFINED ACROSS FOOTHILLS AND MTNS. HOWEVER...CONDENSATION PRESSURE DEFICITS DECREASE TO NEAR ZERO ACROSS THE I-85 CORRIDOR TERMINALS AND MTNS VALLEYS. OUTLOOK...LOW LEVEL MOISTURE MAY CREATE RESTRICTIONS AGAIN TUESDAY MORNING. A COLD FRONT IS EXPECTED TO CROSS THE REGION TUESDAY NIGHT...WITH DRY HIGH PRES RETURNING MID TO LATE WEEK. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...LGL SHORT TERM...MCAVOY LONG TERM...SBK AVIATION...LGL/NED
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
308 AM MST SUN DEC 2 2012 .DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHWESTERN SK...WITH WARM FRONT EXTENDING SOUTHEASTWARD ACROSS NORTHEASTERN MT INTO SOUTHWESTERN ND AND CENTRAL SD. COLD FRONT EXTENDS WESTWARD FROM THE LOW ACROSS SOUTHWESTERN CANADA. UPPER LEVEL ANALYSIS CONTINUES TO SHOW LOW OFF THE PACIFIC NW COAST...WITH FAST WEST TO SOUTHWEST FLOW ACROSS THE WESTERN CONUS INTO THE PLAINS. HIGH CLOUDINESS CONTINUES TO PASS OVER THE REGION WITH VARIABLY CLOUDY SKIES. TEMPS ARE MOSTLY IN THE 30S AND LOWER 40S ACROSS THE AREA...WITH WARMER TEMPS ACROSS PORTIONS OF NORTHEASTERN WY AND THE BLACK HILLS AREA WHERE THERE ARE DOWNSLOPING WINDS. WINDS ARE GENERALLY FROM THE WEST TO SOUTHWEST ACROSS THE FORECAST AREA...BREEZY AT TIMES ACROSS PORTIONS OF NORTHEASTERN WY. WARM CONDITIONS WILL CONTINUE TODAY...WITH TEMPS 20 TO 30 DEGREES ABOVE AVERAGE. GUSTY SOUTHWESTERLY WINDS CAN BE EXPECTED ACROSS NORTHEASTERN WY AND PORTIONS OF THE BLACK HILLS LATER THIS MORNING INTO TONIGHT. COLD FRONT WILL MOVE ACROSS THE FORECAST AREA LATE TONIGHT...BRINGING A CHANCE OF SHOWERS TO MAINLY NORTHERN PORTIONS OF THE AREA AND STRONG NORTHWESTERLY WINDS FOR MONDAY ACROSS NORTHWESTERN SD. TEMPS WILL BE COOLER THROUGH THE FIRST HALF OF THE COMING WEEK...BUT STILL ABOVE AVERAGE. FOR TODAY...SKIES WILL BE PARTLY TO MOSTLY SUNNY WITH HIGH CLOUDS PASSING OVERHEAD. HIGHS WILL RANGE FROM THE MID 50S OVER THE HIGHER BLACK HILLS TO THE UPPER 60S TO NEAR 70 DEGREES ACROSS PORTIONS OF THE SOUTHWESTERN AND SOUTH CENTRAL SD PLAINS. NEAR RECORD HIGHS ARE EXPECTED OVER PORTIONS OF THE AREA...WITH THE RECORD HIGH FOR THIS DATE AT RAP AIRPORT BEING 69 AND EAST RAPID CITY AT 70. SOUTHWESTERLY WINDS WILL INCREASE ACROSS NORTHEASTERN WY AND THE BLACK HILLS LATER THIS MORNING...BECOMING RATHER GUSTY BY THE AFTERNOON IN FAVORED AREAS. SOME WIND GUSTS TO NEAR 50 MPH ARE LIKELY ACROSS CAMPBELL CO WY AND DOWNSLOPE AREAS OF THE NORTHERN BLACK HILLS. THESE GUSTY WINDS WILL CONTINUE INTO THE EVENING UNTIL THE COLD FRONT PASSES. COLD FRONT WILL PASS THROUGH NORTHWESTERN PORTIONS OF THE CWA LATE THIS EVENING AND THROUGH THE REST OF THE FORECAST AREA LATE TONIGHT. UPPER LOW ASSOCIATED WITH FRONT WILL PASS WELL TO THE NORTH OF THE REGION...WITH WEAKER SHORTWAVE ENERGY PASSING ACROSS OUR AREA WITH THE FRONT. SHOWER CHANCES WILL MAINLY BE CONFINED TO NORTHERN PORTIONS OF THE CWA...WITH THE BEST CHANCES ACROSS THE NORTHERN BLACK HILLS AREA LATE TONIGHT. PCPN WILL GENERALLY BE IN THE FORM OF RAIN...EXCEPT FOR POSSIBLY A LITTLE SNOW ACROSS THE HIGHER ELEVATIONS OF THE BLACK HILLS. WINDS WILL SWITCH TO THE NORTHWEST BEHIND THE FRONT AND LIKELY BE RATHER GUSTY FOR A PERIOD BEHIND THE PASSAGE. SHOWERS SHOULD EXIT THE AREA BY MONDAY MORNING...BUT IF TIMING OF FRONT IS A BIT SLOWER...THERE COULD BE A LINGERING CHANCE INTO THE EARLY MORNING ACROSS FAR EASTERN PORTIONS OF THE CWA. WINDS WILL INCREASE MONDAY MORNING AS SUBSIDENCE DEVELOPS BEHIND EXITING SHORTWAVE...COOLER AIR BUILDS IN TO THE AREA...AND BOUNDARY LAYER MIXES OUT. ADVISORY CRITERIA WINDS STILL LOOK LIKELY DURING THE LATE MORNING AND EARLY AFTERNOON HOURS ACROSS A GOOD PORTION OF THE NORTHWESTERN SD PLAINS. FURTHER SOUTH INTO THE WEST CENTRAL SD PLAINS...INCLUDING THE RAP AREA...THERE IS MORE UNCERTAINTY OF STRONG WINDS WITH FLOW A BIT MORE WESTERLY THAN IS USUALLY FAVORABLE FOR STRONGER WINDS. HIGHS WILL BE MOSTLY IN THE 50S...WITH SOME 40S ACROSS PORTIONS OF NORTHEASTERN WY AND THE BLACK HILLS. WINDS WILL DECREASE BY MONDAY EVENING...WITH QUIET WEATHER EXPECTED INTO MIDWEEK. TEMPS WILL REMAIN ABOVE AVERAGE WITH HIGHS IN THE MID 40S TO MID 50S ON TUESDAY AND LOWS IN THE 20S AND LOWER 30S. EXTENDED...WARM AND DRY CONDITIONS WILL OCCUR ON WEDNESDAY WITH ZONAL FLOW OVER THE AREA. A SFC COLD FRONT WILL BRING A CHANCE OF RAIN OR SNOW AS IT PASSES THROUGH ON WEDNESDAY NIGHT. SHORTWAVE ENERGY IN A BROAD UPPER TROUGH WILL CREATE A CHANCE OF RAIN OR SNOW FROM THURSDAY INTO FRIDAY. TEMPERATURES ON THURSDAY WILL BE NEAR NORMAL...WITH COLDER TEMPERATURES ON FRIDAY AND SATURDAY. MODEL SOLUTIONS DIVERGE FOR SATURDAY AND SUNDAY...BUT WITH THE POTENTIAL FOR AN UPPER TROUGH TO AFFECT THE REGION...WILL KEEP LOW POPS IN THE FORECAST FOR THE END OF THE WEEK. && .AVIATION...12Z TAFS VFR CONDITIONS WILL PREVAIL TODAY WITH AREAS OF MID AND HIGH LEVEL CLOUDS. THERE IS A CHANCE OF SHOWERS TONIGHT OVER NORTHEASTERN WYOMING...THE BLACK HILLS AND NORTHWESTERN SOUTH DAKOTA. AREAS OF MVFR CIGS MAY DEVELOP WITH THE SHOWERS...ESPECIALLY OVER PARTS OF NORTHEASTERN WYOMING AND THE BLACK HILLS LATE TONIGHT. GUSTY SOUTHWEST WINDS WILL BE FOUND ACROSS NORTHEASTERN WYOMING AND PARTS OF THE BLACK HILLS TODAY. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...26 LONG TERM....10 AVIATION...10
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
620 AM CST SUN DEC 2 2012 .UPDATE...FOR 12Z AVIATION FORECAST && .AVIATION... MOISTURE TRANSPORT IS JUST NOT IMPRESSIVE AS FAR AS MIDDLE TENNESSEE IS CONCERNED WITH BETTER TRANSPORT OCCURRING NORTHWARD DURING THE DAY ALONG THE OHIO RIVER AND POINTS NORTH. MOISTURE TRANSPORT EVEN BECOMES WEAKER BY AFTERNOON. THEREFORE EXPECT ISOLATED TO SCATTERED LIGHT SHOWERS OR SPRINKLES TODAY MAINLY INTERSTATE 40 NORTHWARD WITH VFR CONDITIONS PREVAILING DURING THE DAY AT AVIATION TERMINALS. WITH WINDS AT THE TOP OF THE BOUNDARY LAYER ON THE ORDER OF 40 KNOTS DURING THE DAY AND A RATHER TIGHT PRESSURE GRADIENT LOOK FOR GUSTS TO 22 KNOTS AT THE SURFACE. I EXPECT CEILINGS WILL LOWER TO MVFR AT CKV AFTER 03/00Z. BOYD && .PREV DISCUSSION... /ISSUED 327 AM CST SUN DEC 2 2012/ DISCUSSION... FOR THE SHORT TERM...RADAR AND IR SATELLITE INDICATES SOME ISOLATED LIGHT SHOWER ACTIVITY...LIKELY STRUGGLING TO REACH THE SURFACE...IN SOUTHERN IL/IN AND WESTERN KY. HRRR AND RUC ALONG WITH THE GFS/NAM/ECMWF ARE STUBBORN TO LEAVE THE NORTHWEST CORNER OF MIDDLE TN OUT OF POP CHANCES AND HAVE ACTUALLY INCREASED THE POP CHANCES UP THERE. THE AREA OF DEVELOPMENT IS EITHER COINCIDENT OR IN CLOSE PROXIMITY TO THE LOW LEVEL JET CURRENTLY OVER THE MO BOOTHEEL AND SOUTHERN IN. VAD WIND PROFILES AT BOTH HPX AND OHX SHOW 40 KT 2 AND 4 KFT WINDS AND WHILE INSTABILITY IS STILL VERY LOW...THE TURBULENCE AND LOW LEVEL MOISTENING OF THE COLUMN ACCORDING TO LAPS/RUC SOUNDINGS IN THE CKV AREA AND THE APPROACHING SURFACE TROUGH AXIS ARE ENOUGH VARIABLES FOR KEEPING IN THE SLIGHT CHANCE FOR THE NORTHWEST THROUGH 00Z MONDAY. SREF ENSEMBLES KEEP THE ACTIVITY RIGHT ALONG THE KY/TN BORDER THROUGH TOMORROW MORNING SO ALSO INCLUDED A SLIGHT CHANCE FOR THE NORTHERN PERIPHERY OF THE CWA. AS FAR AS TEMPS GO...KEPT THE NORTHWEST AND NORTH A FEW DEGREES BELOW GUIDANCE AS CLOUD COVER SHOULD BE PRESENT NORTH OF I40 THROUGHOUT THE DAY. LIKEWISE...KEPT MIN TEMPS HIGHER THERE AS WELL FOR TOMORROW MORNING. LOOKING TOWARDS TUESDAY...ONCE AGAIN...HAVE PRETTY GOOD CONFIDENCE IN THE PREVIOUS FORECAST DEPICTION OF THE APPROACHING COLD FRONT PROGGED TO IMPACT MIDDLE TN BY 00Z WEDNESDAY GIVE OR TAKE A COUPLE HOURS. THE ONLY NOTICEABLE DIFFERENCE IS THE INCREASING INSTABILITY VALUES...SOUNDING CAPE VALUES NOW NEAR 400 J/KG...LIKELY DUE TO THE COOLER MID LEVELS BEING DEPICTED AND THE SURFACE TEMPS NEAR 70. THIS SHOULD TRANSLATE TO SOME BRIEF LOCALIZED DOWNPOURS...ESPECIALLY IN THE NORTHWEST QUARTER OF THE CWA. FOR THE EXTENDED...MODEL DISAGREEMENT CONTINUES. GFS STALLS A COLD FRONT TO OUR NORTHWEST BY SATURDAY NIGHT KEEPING US RAINY THROUGH TUESDAY OF THE FOLLOWING WEEK WHILE THE ECMWF SLOWLY BRINGS THE COLD FRONT THROUGH THE BY LATE SUNDAY. WHILE THE UPPER LEVEL PATTERNS DIFFER QUITE A BIT...THEY BOTH AT LEAST AGREE THAT RAIN WILL BE IN THE FORECAST FOR THE WEEKEND. SO AT THE VERY LEAST...THE CONFIDENCE IN LEAVING POP CHANCES IN THE EXTENDED HAS RISEN...BUT THE SPEFICICS OF WHEN AND WHERE ARE YET TO BE DETERMINED. WILL DEFER TO LATER MODEL RUNS AND SHIFTS TO FINE TUNE THE EXTENDED. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
327 AM CST SUN DEC 2 2012 .DISCUSSION... FOR THE SHORT TERM...RADAR AND IR SATELLITE INDICATES SOME ISOLATED LIGHT SHOWER ACTIVITY...LIKELY STRUGGLING TO REACH THE SURFACE...IN SOUTHERN IL/IN AND WESTERN KY. HRRR AND RUC ALONG WITH THE GFS/NAM/ECMWF ARE STUBBORN TO LEAVE THE NORTHWEST CORNER OF MIDDLE TN OUT OF POP CHANCES AND HAVE ACTUALLY INCREASED THE POP CHANCES UP THERE. THE AREA OF DEVELOPMENT IS EITHER COINCIDENT OR IN CLOSE PROXIMITY TO THE LOW LEVEL JET CURRENTLY OVER THE MO BOOTHEEL AND SOUTHERN IN. VAD WIND PROFILES AT BOTH HPX AND OHX SHOW 40 KT 2 AND 4 KFT WINDS AND WHILE INSTABILITY IS STILL VERY LOW...THE TURBULENCE AND LOW LEVEL MOISTENING OF THE COLUMN ACCORDING TO LAPS/RUC SOUNDINGS IN THE CKV AREA AND THE APPROACHING SURFACE TROUGH AXIS ARE ENOUGH VARIABLES FOR KEEPING IN THE SLIGHT CHANCE FOR THE NORTHWEST THROUGH 00Z MONDAY. SREF ENSEMBLES KEEP THE ACTIVITY RIGHT ALONG THE KY/TN BORDER THROUGH TOMORROW MORNING SO ALSO INCLUDED A SLIGHT CHANCE FOR THE NORTHERN PERIPHERY OF THE CWA. AS FAR AS TEMPS GO...KEPT THE NORTHWEST AND NORTH A FEW DEGREES BELOW GUIDANCE AS CLOUD COVER SHOULD BE PRESENT NORTH OF I40 THROUGHOUT THE DAY. LIKEWISE...KEPT MIN TEMPS HIGHER THERE AS WELL FOR TOMORROW MORNING. LOOKING TOWARDS TUESDAY...ONCE AGAIN...HAVE PRETTY GOOD CONFIDENCE IN THE PREVIOUS FORECAST DEPICTION OF THE APPROACHING COLD FRONT PROGGED TO IMPACT MIDDLE TN BY 00Z WEDNESDAY GIVE OR TAKE A COUPLE HOURS. THE ONLY NOTICEABLE DIFFERENCE IS THE INCREASING INSTABILITY VALUES...SOUNDING CAPE VALUES NOW NEAR 400 J/KG...LIKELY DUE TO THE COOLER MID LEVELS BEING DEPICTED AND THE SURFACE TEMPS NEAR 70. THIS SHOULD TRANSLATE TO SOME BRIEF LOCALIZED DOWNPOURS...ESPECIALLY IN THE NORTHWEST QUARTER OF THE CWA. FOR THE EXTENDED...MODEL DISAGREEMENT CONTINUES. GFS STALLS A COLD FRONT TO OUR NORTHWEST BY SATURDAY NIGHT KEEPING US RAINY THROUGH TUESDAY OF THE FOLLOWING WEEK WHILE THE ECMWF SLOWLY BRINGS THE COLD FRONT THROUGH THE BY LATE SUNDAY. WHILE THE UPPER LEVEL PATTERNS DIFFER QUITE A BIT...THEY BOTH AT LEAST AGREE THAT RAIN WILL BE IN THE FORECAST FOR THE WEEKEND. SO AT THE VERY LEAST...THE CONFIDENCE IN LEAVING POP CHANCES IN THE EXTENDED HAS RISEN...BUT THE SPEFICICS OF WHEN AND WHERE ARE YET TO BE DETERMINED. WILL DEFER TO LATER MODEL RUNS AND SHIFTS TO FINE TUNE THE EXTENDED. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 69 55 74 55 / 20 05 05 10 CLARKSVILLE 67 57 75 56 / 20 20 05 10 CROSSVILLE 64 51 69 52 / 10 05 05 05 COLUMBIA 71 52 74 54 / 10 05 05 10 LAWRENCEBURG 71 51 74 53 / 05 05 05 10 WAVERLY 67 56 75 56 / 20 05 05 20 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TB12
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 AM CST SUN DEC 2 2012 .SHORT TERM...TODAY THROUGH TUESDAY 330 AM CST SUN DEC 2 2012 FORECAST CONCERNS FOCUS ON THE DENSE FOG THIS MORNING...THEN THE NEXT PCPN CHANCE AND AMOUNT OF WARMING FOR MONDAY. AN AREA OF CLEARING HAS OPENED UP OVER SOUTHERN MN/FAR NORTHERN IA EARLY THIS MORNING...PER FOG/STRATUS SATELLITE IMAGERY...BUT THERE IS ALSO EVIDENCE OF SOME SOUTHERN PUSH IN LOW STRATUS FROM NORTHERN MN. MEANWHILE...SFC OBS SHOW A WIDE VARIETY OF VSBYS...WITH MOST OF THE DENSE FOG ACROSS IA...MOSTLY AHEAD OF A SFC FRONT. RAP13 RH TRENDS WOULD TAKE THE BULK OF THE LOW SATURATION EAST EARLY THIS MORNING...PUSHING THE CLEARING AREA INTO WESTERN WI BY 15Z OR SO. SOME LIGHT STIRRING IN THE WIND BEHIND THE FRONT SEEMS TO HAVE A POSITIVE IMPACT ON THE FOG...IMPROVING VSBYS A BIT. WINDS PROBABLY WON/T PICK UP BEYOND THE LIGHT VARIETY UNTIL LATER IN THE AFTERNOON AS A WEAK HIGH PRESSURE RIDGE SHIFTS OVER EASTERN WI BY 00Z. WHILE SOME VSBYS HAVE IMPROVED OVER THE FORECAST AREA...THEY ARE SHOWING SIGNS OF GOING DOWN AGAIN. WILL SIT WITH THE DENSE FOG ADVISORY AS IS AS A RESULT...BUT SEE THE POTENTIAL FOR CANCELLING SOME AREAS BEFORE 15Z BASED ON TRENDS. MEANWHILE...THE RAP13 BUFKIT SOUNDING AT KLSE HOLDS ONTO A STRONG INVERSION THROUGH 18Z...AND THE LOW STRATUS COULD HANG AROUND AS A RESULT. IT MAY NOT BREAK UP UNTIL LATE IN THE AFTERNOON. A SHORTWAVE TROUGH...JUST PUSHING ONTO THE WEST COAST EARLY THIS MORNING - PER LATEST WATERVAPOR SATELLITE IMAGERY...WILL DRIVE DUE EAST OVER THE NEXT COUPLE DAYS...MOVING ACROSS SOUTHERN CANADA AND THEN DROPPING OVER THE GREAT LAKES ON TUE. ITS SFC FRONT WILL BE FOUND WELL AHEAD OF THE UPPER LEVEL TROUGH...MOVING INTO WESTERN WI MONDAY AFTERNOON. THIS HAS BEEN A CONSISTENT SIGNAL IN THE MODELS. DECENT FRONTOGENETIC FORCING INDICATED WITH THE BOUNDARY WITH A FETCH OF LOW LEVEL MOISTURE RETURN AHEAD OF IT. THE NAM EVEN SUGGESTS AS MUCH AS 500 J/KG OF MUCAPE AHEAD OF THE FRONT. THE GFS IS MUCH WEAKER. THE BETTER UPPER LEVEL FORCING WILL STAY NORTH WITH THE SHORTWAVE. BUT...ENOUGH LOW LEVEL FORCING AND MOISTURE THAT SOME PCPN LOOKS LIKELY ON MONDAY...MOSTLY AFTERNOON/EVENING. FAIRLY SIMILAR TO WHAT OCCURRED YESTERDAY/EARLY THIS MORNING. AND...JUST LIKE THAT...THE DEPTH OF THE SATURATION IS GOING TO BE A LARGE FACTOR IN WHAT KIND OF PCPN FALLS. TIME/HEIGHT X-SECTIONS AND BUFKIT SOUNDINGS KEEP THE SATURATION FROM 800-850 MB TO THE SFC...WITH SOME MOISTURE ABOVE 500 MB. IN BETWEEN IS RELATIVELY DRY...AND PROBABLY TOO LARGE TO OVERCOME...AT LEAST INITIALLY...FOR A SEEDER/FEEDER PROCESS. THIS SUPPORTS DRIZZLE AS THE MAIN PTYPE...WITH A SETUP MUCH LIKE WHAT OCCURRED TODAY. MIGHT HAVE A BETTER SHOT FOR SHOWERS...AND PERHAPS SOME ISOLATED THUNDER...AS THE FRONT MOVES INTO EASTERN WI...BUT LOCALLY...DON/T THINK THIS WILL OCCUR. MONDAY ALSO LOOKS RELATIVELY WARM WITH 925 MB TEMPS CLIMBING TO 10-14 C AND SREF 850 MB TEMP ANOMALIES OF +2-2.5. THIS HAS ALSO BEEN A CONSISTENT SIGNAL IN THE MODELS. IT WON/T MIX TO 850 MB...BUT IT IS INDICATIVE OF THE ABNORMALLY WARM AIR MOVING IN. THAT SAID...CLOUDS WILL ALSO BE INCREASING AND THICKENING FOR MONDAY...AND THERE WILL BE THE LIKELIHOOD OF PERIODS OF DRIZZLE. THESE FACTORS WILL TEMPER JUST HOW WARM IT COULD GET. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 230 AM CST SUN DEC 2 2012 CONSISTENCY REMAINS GOOD BETWEEN THE VARIOUS EXTENDED MODELS WITH THE OVERALL UPPER LEVEL FLOW/PATTERN FOR MUCH OF THE NEW WORK WEEK. THE GFS/ECMWF/GEM CONTINUE TO POINT TO AN UPPER LEVEL TROUGH SLIDING ACROSS SOUTHERN CANADA AT MID WEEK...DRIVING ITS ASSOCIATED SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY ON THU. THE BETTER UPPER LEVEL FORCING WILL STAY NORTH...BUT A LOW LEVEL MOISTURE FETCH ALONG WITH THE FRONT SHOULD BE ENOUGH TO SPARK SOME PRECIPITATION. COULD SEE SOME PRECIPITATION WED NIGHT AHEAD OF THE FRONT...IN A REGION OF LOW LEVEL WARM AIR ADVECTION. THE FRONT FROM THU WILL CONTINUE TO ACT AS A PCPN FOCUS ON FRI/SAT...BUT LOOKS SHIFTED WELL SOUTH OF THE FORECAST AREA. HOWEVER...THE GFS SUGGESTS THAT A RIPPLE IN THE UPPER LEVEL FLOW WILL RIDE NORTHEAST ALONG THE BOUNDARY...AND COULD BRING ANOTHER ROUND OF PCPN TO THE REGION. THE EC STAYS SOUTH...AND CONSISTENTLY SO. NOT SOLD ON THE GFS AT THIS TIME...AND WILL SIDE WITH THE EC/CONSENSUS SOLUTION FOR POPS FOR NOW. && .AVIATION...THROUGH 06Z MONDAY 1110 PM CST SAT DEC 1 2012 A COLD FRONT MOVED THROUGH KRST DURING THE EVENING AND WAS APPROACHING KLSE AT 05Z. THIS FRONT ALLOWED THE SKIES TO CLEAR AT KRST AS EXPECTED...BUT LINGERING LOW LEVEL MOISTURE AND LIGHT WINDS BEHIND THE FRONT HAS ALLOWED FOR IFR VISIBILITIES TO QUICKLY DEVELOP. AT KLSE...VISIBILITIES REMAIN LOW IN THE LIFR/IFR CATEGORIES WITH CEILINGS SURPRISINGLY CLIMBING TO MVFR. ANTICIPATING BOTH KLSE AND KRST TO DEVELOP DENSE FOG EARLY THIS MORNING WITH VISIBILITIES AND CEILINGS DROPPING TO VLIFR/LIFR. FAVORABLE CONDITIONS INCLUDE THIS CLEARING GOING ON BEHIND THE FRONT...THE LIGHT WINDS AND DRY AIR REMAINING VERY FAR OFF TO THE WEST IN SOUTHWEST MINNESOTA. BOTH SITES SHOULD START TO SEE IMPROVEMENT AFTER SUNRISE...WITH KLSE TAKING THE LONGEST BECAUSE OF MOISTURE GETTING STUCK IN THE VALLEY. IN FACT...IT IS ENTIRELY POSSIBLE THAT STRATUS REMAINS STUCK IN THE VALLEY THROUGH THE ENTIRE DAY SUNDAY...BUT FOR NOW FOLLOWED THE RAP MODEL WHICH SUGGESTS SCATTERING OUT AROUND 21Z. KRST SHOULD GO VFR BY NOON WITH A THINNER STRATUS DECK IN PLACE. VFR CONDITIONS SHOULD BE THE RULE INTO THE EVENING AS SOUTH WINDS BEGIN TO INCREASE AHEAD OF DEEPENING LOW PRESSURE IN THE PLAINS. THIS LEADS TO ONE LAST CONCERN WHICH IS LOW LEVEL WIND SHEAR TOWARDS 06Z MONDAY AND BEYOND AT BOTH TAF SITES. HAVE NOT INCLUDED THIS CONCERN IN THE TAF SITES BEING AT THE END OF THE 24 HOUR TAF PERIOD. LOOKING BEYOND 06Z MONDAY...STRATUS LOOKS LIKELY TO REDEVELOP AT BOTH TAF SITES AS SOUTHERLY WINDS INCREASE FURTHER AND BRING IN GULF OF MEXICO MOISTURE AGAIN. CEILINGS OF IFR OR LOWER MAY OCCUR. && .ARX WATCHES/WARNINGS/ADVISORIES... 330 AM CST SUN DEC 2 2012 WI...DENSE FOG ADVISORY UNTIL 9 AM CST TODAY FOR WIZ017-029-032>034- 041>044-053>055-061. MN...DENSE FOG ADVISORY UNTIL 9 AM CST TODAY FOR MNZ079-086>088- 094>096. IA...DENSE FOG ADVISORY UNTIL 9 AM CST TODAY FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION.....AJ
PREVIOUS FORECAST DISCUSSION ISSUED AT 228 PM...

MAIN FORECAST CONCERN IS WITH THE TEMPERATURES AND RAIN CHANCES MONDAY. SURFACE ANALYSIS THIS AFTERNOON SHOWS A COLD FRONT EXTENDING FROM NORTHWEST MINNESOTA INTO CENTRAL NEBRASKA. A FEW REPORTS ACROSS EASTERN IOWA OF SOME LIGHT RAIN AND DRIZZLE AHEAD OF THE FRONT ACROSS EASTERN IOWA. WATER VAPOR SATELLITE SHOWS A WEAK SHORT WAVE TROUGH ALONG THE MONTANA/NORTH DAKOTA BORDER. THE 01.12Z MODELS ALL SHOW THIS WAVE MOVING STRAIGHT EAST ACROSS LAKE SUPERIOR INTO SOUTHERN ONTARIO TONIGHT. THE BEST PV ADVECTION IN THE 500-300 MB LAYER WILL STAY TO THE NORTH OF THE AREA TONIGHT AND IS ONLY EXPECTED TO BE BETWEEN 4 AND 8 PVU/S. THE BEST QG CONVERGENCE IN THE 1000-700 MB LAYER WILL ALSO PASS BY TO THE NORTH THIS AFTERNOON. THE ISENTROPIC UP GLIDE ON THE 290K SURFACE WILL BE THE BEST THIS AFTERNOON AND THEN MOVE OFF TO THE EAST OF THE AREA AFTER 00Z. WITH THE FORCING BEING THE BEST THIS AFTERNOON...THE INCREASE IN THE REPORTS OF LIGHT RAIN AND DRIZZLE IS OCCURRING AS EXPECTED...BUT AS THE FORCING MOVES OFF THE EAST QUICKLY AFTER 00Z...EXPECT TO SEE THE LIGHT PRECIPITATION BE ON THE DECLINE. HAVE THUS BROUGHT THE PRECIPITATION CHANCES DOWN TO A MAXIMUM OF 40 PERCENT ACROSS THE EAST FOR THIS EVENING WITH ALL OF IT ENDING BETWEEN 06Z AND 09Z. SOME CONCERN AS TO WHETHER ANY FOG WILL FORM ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA TONIGHT. PLENTY OF LOW LEVEL MOISTURE WILL REMAIN IN PLACE EVEN AFTER THE COLD FRONT MOVES THROUGH. BY LATE TONIGHT...THE SURFACE WINDS WILL BE DECREASING BUT THE 01.12Z NAM BUFKIT SOUNDINGS SUGGEST THE POTENTIAL FOR AROUND 10 KNOTS TO PERSIST JUST ABOVE THE SURFACE AROUND 1K FEET. VISIBLE SATELLITE SHOWS CLEARING ALONG THE FRONT THAT IS EXPECTED TO MOVE IN WITH THE FRONT OVERNIGHT. THE CONCERN IS JUST WHEN THE CLEARING WILL ARRIVE AND IF THERE WILL BE ENOUGH TIME FOR FOG TO DEVELOP UNDER THE CLEAR SKIES. WILL INCLUDE SOME FOG IN THE GRIDDED FORECAST BUT WILL NOT GO WITH DENSE FOG AT THIS TIME. THE NEXT SYSTEM IS SET TO MOVE ACROSS THE UPPER MIDWEST MONDAY. THIS SYSTEM LOOKS TO BE STRONGER THAN THE WAVE FOR TODAY BUT WILL ALSO TRACK NORTH WITH THE MAIN WAVE GOING ALONG THE CANADIAN BORDER. THIS ONCE AGAIN TAKE THE BEST PV ADVECTION IN THE 500-300 MB LAYER WITH BOTH THE NAM AND GFS ONLY SHOWING AROUND 4 PVU/S COMING ACROSS THE NORTHERN PART OF THE FORECAST AREA. THE QG CONVERGENCE WITH THIS WAVE LOOKS TO BE WEAK TO MODERATE IN THE 1000-500 MB LAYER WITH 2-3 UBAR/S OF UP GLIDE ON THE 295K LAYER. THIS SYSTEM LOOKS LIKE IT WILL HAVE THE POTENTIAL TO PRODUCE SOME LIGHT PRECIPITATION AGAIN BUT LIKE THE LAST TWO SYSTEMS...THE DEPTH OF SATURATION COMES INTO PLAY. THE FORECAST BUFKIT SOUNDINGS SHOWS SATURATION UP TO ABOUT 5K FEET WITH PLENTY OF DRY AIR ABOVE THAT. THE RAISES THE CONCERN OF WHETHER THE PRECIPITATION TYPE WILL BE LIGHT RAIN OR DRIZZLE. PLAN TO INTRODUCE DRIZZLE AND CARRY BOTH TYPES FOR NOW. ALSO CONCERNED ABOUT TEMPERATURES AHEAD OF THIS SYSTEM. FORECAST SOUNDINGS SHOW THE WARMEST AIR ALOFT WILL RESIDE BETWEEN 900 AND 800 MB AND THAT THE LOW LEVEL INVERSION BELOW THIS NEVER MIXES OUT ALLOWING THE WARM AIR TO BE TAPPED INTO. ALSO...AS THE LOW LEVEL MOISTURE RETURNS AHEAD OF THIS SYSTEM...THE LOW LEVELS UNDER THE INVERSION BECOME SATURATED WHICH COULD BE SETTING THE AREA UP FOR ANOTHER DAY OF FOG AND LOW CLOUDS. IF THIS OCCURS...VERY LIMITED TEMPERATURE RISES WOULD BE EXPECTED AND COULD KEEP THE HIGHS ANYWHERE FROM 5 TO 10 DEGREES UNDER THE FORECAST TEMPERATURES. STARTED TO TREND TOWARD THIS WILL A SLIGHT DOWNWARD NUDGE IN THE TEMPERATURES. .LONG TERM...TUESDAY THROUGH SATURDAY 228 PM CST SAT DEC 1 2012 LITTLE OVERALL CHANGE IN THE PATTERN IS EXPECTED TO OCCUR WITH A ZONAL TO WEAK NORTHWEST FLOW BRINGING IN NORTHERN STREAM SYSTEMS. THE EXTENDED MODELS ARE IN GOOD AGREEMENT THAT THE NEXT SHORT WAVE TROUGH IN THIS FLOW PATTERN WILL TRACK ACROSS SOUTHERN CANADA AND THE UPPER MIDWEST WEDNESDAY NIGHT AND THURSDAY. THIS SYSTEM WILL PUSH ANOTHER COLD FRONT THROUGH THE REGION WITH LIGHT PRECIPITATION POSSIBLE ALONG AND AHEAD OF THE FRONT. SOME SLIGHT DIFFERENCES ON HOW LONG THE PRECIPITATION WILL LINGER WITH MOST MODELS ENDING IT LATE THURSDAY OR THURSDAY EVENING. THE REST OF THE PERIOD LOOKS TO BE DRY AT THIS POINT AS HIGH PRESSURE BUILDS IN AT THE SURFACE. && .AVIATION...THROUGH 06Z MONDAY 1110 PM CST SAT DEC 1 2012 A COLD FRONT MOVED THROUGH KRST DURING THE EVENING AND WAS APPROACHING KLSE AT 05Z. THIS FRONT ALLOWED THE SKIES TO CLEAR AT KRST AS EXPECTED...BUT LINGERING LOW LEVEL MOISTURE AND LIGHT WINDS BEHIND THE FRONT HAS ALLOWED FOR IFR VISIBILITIES TO QUICKLY DEVELOP. AT KLSE...VISIBILITIES REMAIN LOW IN THE LIFR/IFR CATEGORIES WITH CEILINGS SURPRISINGLY CLIMBING TO MVFR. ANTICIPATING BOTH KLSE AND KRST TO DEVELOP DENSE FOG EARLY THIS MORNING WITH VISIBILITIES AND CEILINGS DROPPING TO VLIFR/LIFR. FAVORABLE CONDITIONS INCLUDE THIS CLEARING GOING ON BEHIND THE FRONT...THE LIGHT WINDS AND DRY AIR REMAINING VERY FAR OFF TO THE WEST IN SOUTHWEST MINNESOTA. BOTH SITES SHOULD START TO SEE IMPROVEMENT AFTER SUNRISE...WITH KLSE TAKING THE LONGEST BECAUSE OF MOISTURE GETTING STUCK IN THE VALLEY. IN FACT...IT IS ENTIRELY POSSIBLE THAT STRATUS REMAINS STUCK IN THE VALLEY THROUGH THE ENTIRE DAY SUNDAY...BUT FOR NOW FOLLOWED THE RAP MODEL WHICH SUGGESTS SCATTERING OUT AROUND 21Z. KRST SHOULD GO VFR BY NOON WITH A THINNER STRATUS DECK IN PLACE. VFR CONDITIONS SHOULD BE THE RULE INTO THE EVENING AS SOUTH WINDS BEGIN TO INCREASE AHEAD OF DEEPENING LOW PRESSURE IN THE PLAINS. THIS LEADS TO ONE LAST CONCERN WHICH IS LOW LEVEL WIND SHEAR TOWARDS 06Z MONDAY AND BEYOND AT BOTH TAF SITES. HAVE NOT INCLUDED THIS CONCERN IN THE TAF SITES BEING AT THE END OF THE 24 HOUR TAF PERIOD. LOOKING BEYOND 06Z MONDAY...STRATUS LOOKS LIKELY TO REDEVELOP AT BOTH TAF SITES AS SOUTHERLY WINDS INCREASE FURTHER AND BRING IN GULF OF MEXICO MOISTURE AGAIN. CEILINGS OF IFR OR LOWER MAY OCCUR. && .ARX WATCHES/WARNINGS/ADVISORIES... 1035 PM CST SAT DEC 1 2012 WI...DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR WIZ017-029-032>034- 041>044-053>055-061. MN...DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR MNZ079-086>088- 094>096. IA...DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...AJ
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
315 AM EST TUE DEC 4 2012 .SYNOPSIS... 08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFYING UPPER LEVEL PATTERN OVER THE CONUS THIS MORNING. NORTHERN STREAM FLOW CONSISTS OF LONGWAVE RIDGING OVER THE PACIFIC COAST FOLLOWED DOWNSTREAM BY A BROAD LONGWAVE TROUGH ACROSS THE MID-SECTION OF THE CONTINENT. THE FLOW THEN FINALLY TURNS BACK TO THE NORTHEAST INTO LONGWAVE RIDGING IN PLACE OVER THE EASTERN SEABOARD/WESTERN ATLANTIC. OUR FORECAST AREA RESIDES AT THE BASE OF THIS RIDGE UNDER 582-584DM HEIGHTS. THE PRESENCE AND INFLUENCE OF THIS UPPER RIDGING CAN AGAIN BE SEEN QUITE WELL ON THE 04/00Z KTBW SOUNDING PROFILE WHICH SHOWS A WELL-DEFINED SUBSIDENCE INVERSION AT 800MB. ANY SIGNIFICANT COLUMN MOISTURE IS SUPPRESSED BENEATH THIS FEATURE. AT THE SURFACE...1025MB HIGH PRESSURE REMAINS CENTERED OFF THE CAROLINA COAST WITH A RIDGE AXIS EXTENDING BACK TO THE WEST THROUGH SOUTHERN/CENTRAL GA/AL. GRADIENT FLOW ON THE SOUTHERN SIDE OF THIS RIDGE AXIS IS PROVIDING AN EASTERLY BOUNDARY LAYER WIND AND AN INFLUX OF ATLANTIC MOISTURE. DEEP LAYER SUPPRESSION IS CURRENTLY STRONG ENOUGH THAT UNLIKE PREVIOUS NIGHTS...WE ARE NOT SEEING ANY ISOLATED SPEED CONVERGENCE SHOWERS MIGRATING WESTWARD FROM THE FL EAST COAST. THERE ARE STILL PERIODS OF LOWER STRATOCU MOVING EAST TO WEST...ESPECIALLY DOWN TOWARD FT MYERS...AND THESE PERIODIC CLOUDS WILL BE AROUND THROUGH THE DAY. TEMPERATURES ARE SEASONABLY WARM WITH MOST LOCATIONS REPORTING IN THE 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH. && .SHORT TERM (TODAY THROUGH THURSDAY)... TODAY/TONIGHT...STACKED RIDGING WILL REMAIN THE DOMINANT PLAYER IN OUR FORECAST THROUGH THE DAY. SHORTWAVE ENERGY WILL BEGIN TO APPROACH THE REGION ALONG THE NORTHERN GULF COAST LATE IN THE DAY...BUT THIS FEATURE SHOULD HAVE LITTLE IMPACT ON THE RIDGE UNTIL VERY LATE TONIGHT AND WEDNESDAY. AT LEAST FOR TODAY...WILL START THE DAY OFF WITH SOME PATCHY FOG...ESPECIALLY NORTH OF THE I-4 CORRIDOR. THE LARGE SCALE SUPPRESSION AND DECENT DIURNAL MIXING WILL RESULT IN ANOTHER WARM DAY REGION-WIDE WITH AFTERNOON HIGH TEMPERATURES IN THE MIDDLE 70S TO AROUND 80 UNDER A MIX OF SUN AND CLOUDS. WILL BEGIN TO SEE A SLOW BREAKDOWN IN HEIGHTS OVERNIGHT AS THE SHORTWAVE CONTINUES IT EASTWARD ADVANCE TOWARD THE REGION. HOWEVER...PLENTY OF RESIDUAL DRY AIR IN THE COLUMN WILL KEEP ANY MENTION OF RAIN OUT OF THE FORECAST. WEDNESDAY...MID/UPPER LEVEL FLOW BECOMES INCREASINGLY CYCLONIC IN NATURE OVER THE FL PENINSULA THROUGH THE DAY. IN THE LOWER LEVELS WILL CONTINUE TO SEE A GENERAL EASTERLY FLOW ON THE SOUTH SIDE OF THE SURFACE RIDGE. A SLOW INCREASE IN SYNOPTIC SUPPORT FOR LIFT AND COLUMN MOISTURE ALONG WITH THE FAVORED EASTERLY FLOW SHOULD INITIATE THE DEVELOPMENT OF EAST COAST SPEED CONVERGENCE SHOWERS THAT THEN TRANSLATE WESTWARD TOWARD THE REGION. THE MAJORITY OF THIS ACTIVITY WILL LIKELY REMAIN ON THE EASTERN SIDE OF THE PENINSULA...BUT FEEL THE SETUP IS FINALLY GOOD ENOUGH TO RE-INTRODUCE A SLIGHT CHANCE FOR ISOLATED SHOWERS ACROSS MANY OF OUR ZONES. ANY SHOWERS THAT DO OCCUR...ARE LIKELY TO BE LIGHT AND BRIEF IN NATURE. WILL SEE MORE IN THE WAY OF CLOUDS FOR WEDNESDAY...BUT STILL ENOUGH SUNNY BREAKS TO ALLOW FOR TEMPS TO REACH THE MID/UPPER 70S. WEDNESDAY NIGHT/THURSDAY...THE SETUP NOW APPEARS MORE FAVORABLE FOR SCT SHOWERS WITH THE SHORTWAVE PASSAGE THAN DURING PREVIOUS FORECAST CYCLES...ESPECIALLY OVER THE SOUTHERN HALF OF THE AREA. FAIRLY SHARP SHORTWAVE WILL APPROACH THE FL WEST COAST WEDNESDAY NIGHT AND THEN CROSS OVER THE AREA DURING THE DAYLIGHT HOURS OF THURSDAY. DECENT SWATH OF DEEP LAYER QG FORCING/SYNOPTIC SUPPORT OVERSPREADS THE AREA THROUGH THURSDAY MORNING. IT ALSO NOW APPEARS THAT MORE IN THE WAY OF COLUMN MOISTURE WILL BE COINCIDENT WITH THIS LIFT. ALL THIS COMBINED WITH A STRENGTHENING EASTERLY FLOW SHOULD SUPPORT EAST TO WEST FAST MOVING SHOWERS. WILL KEEP THIS ACTIVITY ISOLATED IN NATURE FROM TAMPA BAY NORTHWARD ALONG THE NATURE COAST FOR NOW...BUT INCREASING POPS TO CHANCE/SCATTERED RANGE FURTHER SOUTH IN LINE WITH THE BEST Q-VECTOR CONVERGENCE AND DEEP LAYER MOISTURE. THURSDAY AFTERNOON/EVENING WILL SEE THE SHORTWAVE AXIS AND RESULTING LIFT PASSING THE AREA. INCREASING DEEP LAYER SUPPRESSION AND DRYING IN THE WAKE OF THIS AXIS SHOULD END MOST OF THE SHOWER ACTIVITY OVER THE FL WEST COAST BY THURSDAY NIGHT. && .LONG TERM (FRIDAY THROUGH NEXT MONDAY)... POTENT SHORT WAVE TROUGH WILL MOVE EAST OF THE AREA THURSDAY NIGHT WITH CLEARING SKIES IN ITS WAKE. A LARGE AREA OF HIGH PRESSURE WILL BRIDGE ACROSS A DECAYING FRONTAL BOUNDARY TO OUR NORTH. THERE WILL BE NO REAL AIRMASS CHANGE SO WE WILL SEE LITTLE IF ANY CHANGE IN OUR TEMPERATURES AND HUMIDITIES THROUGH THE EXTENDED PERIOD. MODELS SHOW ENOUGH MOISTURE IN THE LOW LEVELS OF THE ATMOSPHERE TO SUPPORT AT LEAST A SLIGHT CHANCE OF SHOWERS EACH DAY FROM SATURDAY THROUGH MONDAY. THERE ARE NO SIGNIFICANT COLD FRONTS THROUGH AT LEAST MONDAY...BUT SOME MODELS SUGGEST THE POSSIBILITY OF A WEAK FRONTAL PASSAGE ON TUESDAY. TEMPERATURES ARE LIKELY TO RUN SEVERAL DEGREES ABOVE NORMAL THROUGH THE PERIOD...ESPECIALLY THE AFTERNOON HIGHS. && .AVIATION... SOME BRIEF PATCHY FOG POSSIBLE AROUND SUNRISE TODAY...OTHERWISE JUST VFR CONDITIONS EXPECTED NEXT 24 HOURS. && .MARINE... HIGH PRESSURE TO THE NORTH OF THE AREA WILL CONTINUE AN EASTERLY FLOW REGIME OVER THE EASTERN GULF OF MEXICO TODAY. NEAR CAUTIONARY LEVEL WINDS OVER THE OFFSHORE WATERS EARLY THIS MORNING WILL DIMINISH BY AFTERNOON. ANOTHER BRIEF SURGE IN WINDS TO NEAR CAUTIONARY LEVELS IS POSSIBLE TONIGHT...ESPECIALLY SOUTH OF TAMPA BAY. WINDS ARE FORECAST WELL BELOW HEADLINE CRITERIA DURING THE MIDDLE PORTION OF THE WEEK AS THE LOCAL GRADIENT RELAXES. HIGH PRESSURE WILL THEN BUILD ONCE AGAIN TO OUR NORTH FOR THE END OF THE WEEK KEEPING AN EASTERLY FLOW REGIME IN PLACE. && FIRE WEATHER... SURFACE HIGH PRESSURE TO THE NORTH OF THE AREA WILL PROVIDE AN EASTERLY FLOW AND ABUNDANT LOW LEVEL ATLANTIC MOISTURE THROUGH WEDNESDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST WEDNESDAY AND WEDNESDAY NIGHT...BUT IS NOW EXPECTED TO DISSIPATE BEFORE REACHING THE FL PENINSULA. A FEW SHOWERS ARE POSSIBLE WEDNESDAY INTO THURSDAY ASSOCIATED WITH THIS SYSTEM...BUT NO SIGNIFICANT RAINFALL IS FORECAST. HIGH PRESSURE WILL ONCE AGAIN BUILD TO OUR NORTH FOR THE END OF THE WEEK. NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 61 77 60 / 0 0 20 20 FMY 79 61 78 61 / 10 10 20 30 GIF 79 57 79 58 / 0 10 20 20 SRQ 78 59 77 60 / 0 0 20 30 BKV 80 51 78 54 / 0 0 20 20 SPG 76 63 76 63 / 0 0 20 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
330 AM EST TUE DEC 4 2012 .DISCUSSION... TODAY...PERSISTENCE FCST WILL BE THE GENERAL RULE AS A LARGE H100-H70 ANTICYCLONE BLANKETING THE ERN SEABOARD CONTINUES TO DOMINATE THE LCL WX PATTERN. CIRCULATION CENTERED OFF THE CAROLINA COAST...DEEP ERLY FLOW TO CONTINUE. MAX TEMPS M-U70S COAST...U70S/L80S INTERIOR. LATEST SAT PICS/RAP ANALYSIS SHOWING A POCKET OF LOW LVL MOISTURE NE OF THE NRN BAHAMAS EMBEDDED WITHIN THE ERLY FLOW...H100-H85 MEAN RH ABV 80PCT...H100-H70 RH AOA 60PCT. AS THIS POCKET PUSHES ACRS THE ISLANDS...EXPECT TO SEE A FEW SHRA BANDS DVLP IN THE CONVERGENT EDDYS ON THEIR LEE SIDE. THESE SHOULD BE SUSTAINED BY THE WARM GULF STREAM WATERS...WHILE THE STRENGTH/DEPTH OF THE LOW LVL ERLY FLOW WOULD PUSH THEM ONSHORE S OF SEBASTIAN INLET. IMPACT WILL BE MINIMAL AS THE LCL SOUNDINGS SHOW A SHARP H85-H70 SUBSIDENCE INVERSION ASSOCD WITH THE RIDGE THAT WILL LIMIT VERTICAL MOTION BLO 10KFT WHILE RAP ANALYSIS SHOWS LITTLE IN THE WAY OF MID/UPR LVL DYNAMIC SUPPORT. TONIGHT...THE RIDGE AXIS WILL BE SHUNTED E/SE THRU DAYBREAK WED AS A FRONTAL TROF EXTENDING FROM THE GREAT LAKES TO THE SRN PLAINS PUSHES TOWARD THE APPALACHIAN RANGE. H100-H70 WINDS WILL RESPOND BY VEERING TO THE SE WHICH SHOULD ALLOW SHRAS TO SPREAD INTO SRN BREVARD/SERN OSCEOLA...BUT AGAIN WITH MINIMAL IMPACT. INCREASED CLOUDS AND INCREASING SRLY WIND COMPONENT SHOULD KEEP MIN TEMPS IN THE U50S/L60S INTERIOR...L/M60S ALONG THE COAST. WED-FRI...HIGH PRESSURE WILL WEAKEN AND MOVE EAST WEDNESDAY AHEAD OF APPROACHING SHORTWAVE. ASSOCIATED SURFACE FRONT WILL WASH OUT TO THE NORTH OF FLORIDA. HIGH PRESSURE TO THE NORTH WILL BRIDGE THE REMAINS OF THE BOUNDARY THROUGH THE LATE WEEK. SOME INCREASE IN LOW LEVEL MOISTURE AND TROFINESS ALOFT SHOULD ALLOW A FEW SHOWERS DURING THIS TIME FRAME. HAVE LOW POPS MENTIONED WITH VALUES A LITTLE HIGHER SOUTHERN COASTAL SECTIONS BY THURS NIGHT FRI WITH DEEPER MOISTURE AND SOME CONVERGENCE DUE TO INVERTED TROF SETTING UP. TEMPS WILL BE ON THE WARM SIDE FOR EARLY DEC WITH HIGHS MID/UPPER 70S...A FEW SPOTS TOPPING 80 SOUTHERN INTERIOR. OVERNIGHT MINS RANGING FROM THE MID/UPPER 50S WELL INLAND/VOLUSIA TO NEAR 60/LOWER 60S ALONG THE COAST SOUTH OF THE CAPE. SAT-MON...WILL CONTINUE WITH ABOVE NORMAL TEMPS THIS WEEKEND AS HIGH TO THE NORTH SLIDES EAST OVER THE ATLANTIC AND LOW LEVEL FLOW VEERS TO A MORE SE-S COMPONENT. SLIGHT CHANCE FOR SHOWERS WITH LINGERING MOISTURE...WILL KEEP AS SLIGHT CHANCE/ISOLATED FOR NOW. && .AVIATION...PREVAILING VFR ALL SITES UNLESS OTHERWISE NOTED. THRU 04/15Z...PTCHY MVFR VSBYS IN BR W OF KDAB-KOBE...BRIEF PDS OF IFR VSBYS N OF I-4. BTWN 04/15Z-05/00Z...LCL MVFR CIGS/VSBYS IN ISOLD PASSING SHRAS S OF KMLB-KGIF...LINE SHIFTING N TO KTIX-KISM AFT 15/00Z. && .MARINE...TODAY-TONIGHT...HI PRES RIDGE CENTERED OFF THE CAROLINA COAST WILL MAINTAIN A GENTLE TO MODERATE E/SE BREEZE ACRS THE LCL ATLC THRU DAYBREAK WED. LATEST BUOY OBS SHOW THE SWELL IMPACTING THE E FL COAST HAS SUBSIDED TO ARND 4FT WHICH THE CURRENT ERLY FLOW SHOULD BE ABLE TO MAINTAIN. STEADY STATE CONDITIONS WITH SEAS 3-5FT NEARSHORE AND 4-6FT OFFSHORE. WHILE THE LATTER MIGHT WARRANT A CAUTIONARY STATEMENT...ALL OF THE OFFSHORE BUOYS ARE INDICATING THE SEAS ARE MAINLY COMPRISED OF A LONG PD SWELL BTWN 8-10SEC WITH SUSTAINED SFC WNDS GENERALLY BLO 15KTS. WILL HOLD OFF ON ANY STATEMENTS. WED-SAT...ONSHORE FLOW WILL PERSIST INTO THE WEEKEND. SEAS WILL GENERALLY BE 3-5 FT...A FEW SPOTS UP TO 6 FEET WELL OFFSHORE. A FEW SHOWERS WILL PERSIST FROM MID WEEK INTO THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... DAB 76 62 75 60 / 0 10 20 20 MCO 81 61 79 59 / 0 10 20 20 MLB 77 64 76 62 / 10 20 20 20 VRB 78 63 77 62 / 20 20 20 20 LEE 81 59 78 58 / 0 10 20 20 SFB 80 61 78 59 / 0 10 20 20 ORL 81 61 78 59 / 0 10 20 20 FPR 78 63 77 62 / 20 20 20 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM....GLITTO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1120 PM CST MON DEC 3 2012 .AVIATION... A COLD FRONT IS NOW WELL EAST OF ALL TERMINAL SITES IN EASTERN IOWA AND NORTHWEST ILLINOIS. WINDS ARE NOW NORTHWESTERLY AROUND 8 TO 10 KTS...AND WILL REMAIN NEAR THAT RANGE THROUGH SUNSET TUESDAY AFTERNOON. A HIGH CIRRUS OVERCAST REMAINS IN PLACE THROUGH THE OVERNIGHT HOURS...BUT SHOULD BECOME TOTALLY CLEAR AT ALL SITES EARLY TUESDAY MORNING. VISIBILITIES WILL BE EXCELLENT ABOVE 10 MILES...THROUGH THE PERIOD...AND BEYOND. ERVIN && .PREV DISCUSSION... /ISSUED 507 PM CST MON DEC 3 2012/ UPDATE... A FORECAST UPDATE WAS SENT EARLY THIS PAST HOUR TO REFLECT A MUCH LESS COVERAGE OF SHOWERS AND SHALLOW THUNDERSTORMS/CONVECTION. THE EAST REMAINS THE MOST LIKELY AREA TO RECEIVE MEASURABLE RAIN...BUT LOCATIONS WEST OF PRINCETON TO STERLING ARE LIKELY TO REMAIN WITH TRACE AMOUNTS. AS FAR AS STRONG STORMS...WINDS ARE VEERING TO THE SOUTHWEST...REDUCING SHEAR AT LOW LEVELS...THIS IS TRUE EXCEPT FOR BUREAU AND PUTNAM COUNTIES...BUT BY THE TIME STORMS REACH THERE...THEY MAY VEER AS WELL. WE REMAIN WATCH FULL...BUT FEEL THE THREAT FOR A SEVERE EVENT IS VERY LOW AND CONFINED TO THE NEXT 1 HOUR...IN THE FAR EAST. ERVIN SYNOPSIS... A COLD FRONT WAS PUSHING INTO CENTRAL IOWA WITH SOUTHERLY WINDS TRANSPORTING UNSEASONABLY WARM AND HUMID AIR INTO THE DVN CWA. RECORD HIGHS HAVE ALREADY BEEN SET OR TIED FOR DECEMBER 3 AT ALL MAJOR CLIMATE SITES. TEMPERATURES WERE ALSO NEARING THE ALL-TIME RECORD HIGHS FOR DECEMBER. CURRENT READINGS WERE IN THE MID 60S TO LOWER 70S WITH DEW POINTS AROUND 60. SPC MESO ANALYSIS INDICATED SBCAPES WERE 500 J/KG AND EFFECTIVE BULK SHEAR WAS 45 KTS EAST OF THE MS RIVER. EXTENSIVE LOW CLOUDS WERE OVER THE CWA BUT SOME BREAKS NOTED ON VISIBLE SATELLITE PICTURES. ELSEWHERE BEHIND THE FRONT TEMPERATURES WERE IN THE 50S WITH DEW POINTS IN THE TEENS...ALONG WITH SUNNY SKIES. HAASE SHORT TERM...TONIGHT AND TUESDAY... FORECAST FOCUS ON CONVECTIVE TRENDS LATE THIS AFTERNOON/EARLY THIS EVENING WITH COLD FRONT. TONIGHT...LOW CLOUDS PUTTING A DAMPER ON THE CONVECTIVE THREAT BUT WILL STILL MENTION SHOWERS LIKELY AND ISOLATED THUNDERSTORMS FROM MAINLY ABOUT THE MS RIVER ON EAST INTO THIS EVENING. HRRR MESO MODEL SEEMS REASONABLE. THE COLD FRONT SHOULD BE NEAR THE MS RIVER ABOUT 6 PM AND WILL HAVE MOVED THROUGH ALL OF THE CWA BEFORE MIDNIGHT SO WILL BE DRY AFTER MIDNIGHT. SKIES WILL CLEAR LATER TONIGHT AS SUBSIDENCE BEHIND UPPER TROUGH SWINGS THROUGH. WILL BE COLDER WITH MIN TEMPS IN THE MID 30S NW TO MID 40S SE. TUESDAY...HIGH PRESSURE BUILDS INTO THE CWA WITH SUNNY SKIES AND COOLER TEMPERATURES...BUT STILL WELL ABOVE NORMAL FOR EARLY DECEMBER. EXPECT AFTERNOON READINGS IN THE 50S ACROSS THE CWA. HAASE LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY... ZONAL UPPER LEVEL FLOW TO CONTINUE THE WARMER THAN NORMAL TEMPERATURES THROUGH THE WORKWEEK WITH PRECIPITATION CHANCES FOCUSED ON A COLD FRONTAL PASSAGE THURSDAY. THE POTENTIAL FOR MUCH COLDER TEMPERATURES AND POSSIBLE WINTRY PRECIPITATION IS STARTING TO LOOK MORE LIKELY WITH THE ARRIVAL OF A MORE DYNAMIC PATTERN OVER THE WEEKEND INTO EARLY NEXT WEEK. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...HIGH PRESSURE DROPPING SOUTHEAST OUT OF THE NORTHERN PLAINS WILL BRING A COLDER AIRMASS INTO THE REGION TUESDAY NIGHT. CLEAR SKIES...LIGHT WINDS...AND 850 MB TEMPERATURES IN THE LOW SINGLE DIGITS SUPPORT LOWS FROM THE MID 20S NORTH TO LOWER 30S SOUTH. WEDNESDAY WILL REMAIN RELATIVELY COOL COMPARED TO THE RECENT WARMTH AS LIGHT SOUTHEAST WINDS OUT OF THE DEPARTING HIGH LIMIT HIGHS TO THE UPPER 30S NORTH TO NEAR 50 IN THE FAR SOUTH. HIGH LEVEL CLOUD COVER WEDNESDAY WELL OUT AHEAD OF THE NEXT FAST MOVING SHORTWAVE WILL HOLD MINS TO THE 30S. THE FASTER ECMWF AND GEM TIMING OF THURSDAY EVENING/S COLD FRONTAL PASSAGE IS PREFERRED OVER THE SLOWER GFS IN THE FAST FLOW ALOFT. MODELS HAVE BACKED OFF SOME ON THE EXTENT OF PREFRONTAL PRECIPITATION...AND HAVE FOLLOWED BY CONFINING LOW CHANCES FOR RAIN SHOWERS TO MAINLY THE AFTERNOON HOURS ACROSS THE NORTHWEST. OTHERWISE...IT WILL BE ANOTHER DAY OF BRISK SOUTHERLY WINDS...CLOUD COVER AND MILD TEMPERATURES AHEAD OF THE FRONT WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. FOLLOWING THE FASTER NON-GFS SOLUTIONS...THE FRONT SHOULD PUSH WELL SOUTHEAST BY FRIDAY MORNING...ALLOWING A DRY NORTH TO NORTHEAST LOW LEVEL FLOW OUT OF THE NEXT HIGH DROPPING INTO THE NORTHERN PLAINS. HOWEVER...DUE TO THE INPUT OF THE SLOWER...MORE NORTHERLY GFS FRONTAL SOLUTION...SLIGHT CHANCE POPS ARE CARRIED INTO THE FRIDAY PERIOD. TEMPERATURES WILL BE NOTICEABLY COOLER AS HIGHS RETURN TO THE 40S. SATURDAY THROUGH MONDAY...LATEST MODEL SOLUTIONS GENERALLY AGREE ON AN EVOLUTION TO A MORE AMPLIFIED UPPER LEVEL FLOW AS A BUILDING RIDGE IN THE EASTERN PACIFIC INDUCES A LONGWAVE TROUGH DOWNSTREAM IN THE WESTERN U.S. THIS SETS UP AN UPPER LEVEL SOUTHWEST FLOW OVER A STALLED FRONTAL BOUNDARY THROUGH THE MID MS VALLEY...FAVORABLE FOR MORE WINTRY TYPE SYSTEMS OVER THE LOCAL AREA. HOWEVER...DUE TO HIGH MODEL VARIABILITY FROM RUN TO RUN AND BETWEEN MODELS...CONFIDENCE IN DETAILS IN THESE PERIODS REMAINS LOW. OVER THE PAST FEW RUNS...THE ECMWF APPEARS TO HAVE THE BEST CONTINUITY WITH ITS MORE PHASED DEPICTION OF THE LEAD SHORTWAVES THAT COULD RESULT IN THE REGION/S FIRST WINTER STORM SYSTEM TRACKING FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT. THE 12Z GFS HAS A SIMILAR SURFACE LOW...ALTHOUGH HAS A SLIGHTLY FASTER AND MORE NORTHERLY TRACK. FOR NOW...THE BLENDED MODEL APPROACH WILL KEEP AN EXTENDED PERIOD OF SLIGHT TO LOW END CHANCE POPS FROM FRIDAY NIGHT THROUGH MONDAY...WHICH WILL LIKELY BE NARROWED DOWN IN LATER FORECASTS. ABOVE NORMAL TEMPERATURES ADVERTISED THROUGH THE WEEKEND COULD END UP SEVERAL CATEGORIES TOO HIGH...ESPECIALLY FROM SUNDAY INTO MONDAY. SHEETS CLIMATE... RECORD HIGHS FOR DECEMBER 3... MOLINE.........69 IN 1970 CEDAR RAPIDS...64 IN 1998 DUBUQUE........64 IN 1970 BURLINGTON.....71 IN 1970 MONTHLY RECORD HIGHS... BURLINGTON.....73 12/04/1998 CEDAR RAPIDS...69 12/04/1998 DUBUQUE........67 12/04/1998, 24/1889 MOLINE.........71 12/04/1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
306 AM EST TUE DEC 4 2012 .SYNOPSIS... ISSUED AT 306 AM EST TUE DEC 4 2012 A BROKEN LINE OF SHOWERS AHEAD OF A COLD FRONT IS MOVING ACROSS LOWER MICHGIAN EARLY THIS MORNING. THE RAIN WILL MOVE OUT OF THE AREA BY LATE MORNING. WE/LL SEE SOME SUNSHINE THIS AFTERNOON BUT TEMPERATURES WILL BE MUCH COOLER THAN YESTERDAY. THERE IS A CHANCE OF MIXED RAIN AND SNOW FROM THURSDAY THROUGH THE WEEKEND. TEMPERATURES WILL BE NEAR NORMAL. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 FORECAST CONCERNS DEAL PCPN TRENDS THIS MORNING. OVERALL...THE FORECAST HASN/T CHANGED MUCH. REGIONAL RADAR SHOWS A BROKEN BAND OF SHOWERS STRETCHING FROM NRN LAKE HURON SWWD TO NEAR ST LOUIS. THIS PCPN IS ALIGNED ALONG THE COLD FRONT WHICH IS PUSHING THROUGH THE CWA ATTM. LATEST IR LOOP SHOWS COOLING CLOUD TOPS OVER ILLINOIS. THIS IS LIKELY IN RESPONSE TO A WAVE ON THE SRN PORTION OF THE FRONT. HRRR SUGGESTS WE/LL SEE A LARGER AREA OF PCPN MOVE INTO THE SRN/SE CWA PRIOR TO SUNRISE AS THE WAVE MOVES NEWD. THIS JUST APPEARS TO BE RAIN...LIGHTNING REMAINS WELL SW OF THE GREAT LAKES. PCPN WILL END FROM NW TO SE THIS AFTERNOON AS THE WAVE MOVES MOVES THROUGH. A SECONDARY COLD FRONT WILL MOVE SEWD THROUGH LOWER MICHIGAN TONIGHT. WE MAY BRIEFLY SEE A FEW SHSN DEVELOP ALONG THE LAKE SHORE NORTH OF HOLLAND BUT THEY WON/T AMOUNT TO MUCH AND WILL QUICKLY FADE BY WEDNESDAY MORNING AS CORE OF THE COLD AIR MOVES EAST. HIGH PRESSURE WILL SETTLE OVER THE CWA WEDNESDAY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 HALLENGING FORECAST IN THE EXTENDED AS MODEL CONSISTENCY HAS BEEN POOR THE LAST COUPLE DAYS HANDLING THE DETAILS OF AN INVERTED TROUGH/SFC WAVE MOVING ALONG THE FRONT STALLED ACROSS THE OHIO VALLEY...AND A MORE SIGNIFICANT STORM EARLY NEXT WEEK. WENT WITH LOW CHANCE OR SLIGHT CHANCE POPS EARLY IN THE PERIOD WITH LOW CONFIDENCE ON DETAILS OF WHEN AND WHERE BEST CHANCES FOR PRECIP WITH BE. P-TYPE IS ALSO A TOUGH CALL AS THERMAL PROFILES SUGGEST MIX NORTH AND RAIN SOUTH. A HIGHER IMPACT EVENT IS EXPECTED NEXT WEEK AS STRONG UPPER TROUGH MOVES INTO THE ROCKIES WITH SFC LOW FORMING OVER THE PLAINS AND HEADING FOR LOWER MICHIGAN. AGAIN CONFIDENCE IS LOW ON TIMING DUE TO MODEL DIFFERENCES AND INCONSISTENCY...BUT A MIXED PRECIP TO RAIN THEN OVER TO SNOW SCENARIO IS POSSIBLE EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1137 PM EST MON DEC 3 2012 MVFR CIGS / VSBY WITH SHOWERS WILL ACCOMPANY THE COLD FRONT AS IT MOVES THROUGH THE TAF SITES DURING THE EARLY MORNING HOURS OF TUESDAY. SO FAR THIS EVENING MOST OF THE RAIN HAS BEEN NORTH OF I-96. THERE IS ANOTHER SHORTWAVE (SEEN ON WATER VAPOR LOOPS) OVER KS THIS EVENING. THIS WILL TRAVEL UP THE FRONT TUESDAY AND MAY PROGLONG THE RAIN OVER JXN/LAN TAF SITES DURING THE MID MORNING HOURS OF TUESDAY. COLDER DRIER AIR WILL FOLLOW THE FRONT EVEN SO TUESDAY. THE RESULTS SHOULD BE CLEARING OF THE LOW CLOUDS BY MID MORNING AND MID CLOUDS BY MID AFTERNOON. && .MARINE... ISSUED AT 306 AM EST TUE DEC 4 2012 COLD ADVECTION WILL INCREASE WAVE HEIGHTS TODAY INTO WEDNESDAY. WE EXTENDED THE SCA THROUGH THE AFTERNOON WEDNESDAY. && .HYDROLOGY... ISSUED AT 306 AM EST TUE DEC 4 2012 NO HYDRO ISSUES THIS MORNING QPF LESS THAN A QUARTER INCH IS EXPECTED FROM SHOWERS ALONG THE COLD FRONT THIS MORNING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LMZ844>849. && $$ SYNOPSIS...93 SHORT TERM...93 LONG TERM...OSTUNO AVIATION...WDM HYDROLOGY...93 MARINE...93
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1226 AM EST TUE DEC 4 2012 .SYNOPSIS... MILD TEMPERATURES WILL CONTINUE AHEAD OF A COLD FRONT...EXPECTED TO CROSS THE EASTERN CAROLINAS ON WEDNESDAY. SCATTERED SHOWERS WILL ACCOMPANY THE FRONT. COOLER CONDITIONS ARE EXPECTED AS HIGH PRESSURE BUILDS OVER THE REGION THURSDAY AND FRIDAY...WITH MODERATING TEMPERATURES NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 12:30 AM TUESDAY...AREAS OF FOG...SOME DENSE SPOTS INCLUDED...NOW FORMING. STILL A GOOD POSSIBILITY THAT WE WILL BE ISSUING A DENSE FOG ADVISORY EARLY THIS MORNING. PREVIOUS DISCUSSION FOLLOWS: THE BROAD CENTER OF 1026 MB HIGH PRESSURE IS LOCATED MAYBE A HUNDRED MILES OFFSHORE...BUT A ZONE OF VERY WEAK PRESSURE GRADIENT EXTENDS AS FAR WEST AS GEORGIA. ALTHOUGH SURFACE WINDS ARE VERY LIGHT OR CALM THERE IS A LITTLE BETTER RETURN FLOW ABOVE THE SURFACE IN THE 1000-2000 FT AGL LAYER...ABOUT 10-12 KNOTS. ALTHOUGH NOT AS WIDESPREAD AS LAST NIGHT...SATELLITE IMAGERY REVEALS AN AREA OF ALTOCUMULUS ALONG THE SOUTH CAROLINA COAST WITH BASES IN THE 7000-8000 FT RANGE. THIS CLOUD COVER APPEARS TO BE RELATED TO MOISTURE TRAPPED UNDERNEATH THE SUBSIDENCE INVERSION ALOFT AND SOME WEAK LIFT ALONG THE UPWARD- SLOPING 295K TO 300K ISENTROPIC SURFACES. WHILE I WOULD LIKE TO SAY THESE CLOUDS WILL NOT BE WITH US MUCH LONGER...NAM AND RUC MODELS SHOW CONTINUED MOISTURE AND WEAK LIFT WHICH MAY SUPPORT SOME CLOUDS ALONG THE COAST THROUGH DAYBREAK. THE AMOUNT OF CLOUD COVER IS CRITICALLY IMPORTANT TONIGHT SINCE BOUNDARY LAYER MOISTURE IS VERY RICH BY DECEMBER STANDARDS...AND JUST A FEW HOURS OF CLEAR SKIES AND CALM WINDS SHOULD YIELD WIDESPREAD FOG. MUCH LIKE WE SAW LAST NIGHT THE FOG COULD BECOME DENSE WITH VISIBILITIES DROPPING BELOW 1/4 MILE AT TIMES. GIVEN UNCERTAINTIES IN THE TIMING AND LOCATION OF ANY DENSE FOG WE WILL NOT ISSUE A DENSE FOG ADVISORY AT THIS TIME...BUT ONE MAY BE NEEDED IN THE NEXT 4-6 HOURS. VERY LITTLE CHANGES ARE NEEDED TO THE REMAINDER OF THE FORECAST...WITH LOWS STILL EXPECTED TO FALL INTO THE UPPER 40S TO AROUND 50. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...HIGH PRESSURE ON TUESDAY WILL GIVE WAY TO A QUICK MOVING FRONT ON WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. THE BEST DYNAMICS WILL REMAIN NORTH OF VIRGINIA AND ISENTROPIC FLOW SHOWS SOME UPWARD VERTICAL MOTION BUT IT IS NOT THAT IMPRESSIVE IN THE LAYER`S AT BELOW 300 KELVIN. SO EXPECT SCATTERED SHOWERS WITH LOW QPF VALUES. MAXIMUM TEMPERATURES ARE EXPECTED TO REMAIN IN THE LOWER TO MID 70S FOR TUESDAY AND UPPER 60S ON WEDNESDAY. LOW TEMPERATURES ARE EXPECTED TO BE IN THE MID 50S TUESDAY AND WITH THE COLD AIR ADVECTION BEHIND THE FRONT TEMPERATURES SHOULD DROP INTO THE LOWER TO MID 40S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...MEDIUM RANGE GUIDANCE CONTINUES TO TREND TOWARD A MILDER AND DRIER SCENARIO FOR THE EXTENDED. INITIALLY A ZONAL FLOW ALOFT PREVAILS THEN A POTENT SHORTWAVE DIVES INTO THE EASTERN SLOPES OF THE ROCKIES ALLOWING A SIGNIFICANT RIDGE TO DEVELOP OFF OF THE SOUTHEAST COAST. CONTINUED TO TREND POPS DOWN THROUGH THE PERIOD FOLLOWING HPC AS BERMUDA HIGH PRESSURE WILL BE THE DOMINANT FEATURE FOR OUR AREA. SLIGHT CHANCE POPS REMAIN FOR MONDAY FOR GENERAL CONVECTION OF ALL THINGS AS SOUNDINGS ARE SHOWING CAPE VALUES NEAR 500 J/KG. TOUGH TO FIND FORCING OTHER THAN MESOSCALE FEATURES SUCH AS THE SEA BREEZE AND DIFFERENTIAL HEATING. SEA FOG REMAINS A POSSIBILITY WITH A QUICK CHECK OF SURFACE DEWPOINTS IN THE MID TO UPPER 60S SUNDAY...AND RELATIVELY LIGHT WINDS. TEMPERATURES WILL BE A BIG STORY AS WELL AS POPS ARE OUT OF THE FORECAST AND WITH 850MB TEMPERATURES SLIGHTLY WARMER THAN WE HAVE CURRENTLY...A COUPLE OF DAYS IN THE 70S APPEARS TO BE A GOOD BET. THESE WILL OCCUR SUNDAY AND MONDAY. LEADING UP TO THIS...MORE SEASONAL VALUES CAN BE EXPECTED. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 06Z...EXPECT MVFR/IFR...WITH POSSIBLE LIFR...DUE TO FOG OVERNIGHT AND INTO TUESDAY MORNING. NEARLY CLEAR SKIES AND LIGHT WINDS ARE ALLOWING FOR AN IDEAL RADIATIONAL COOLING CONDITIONS TO ALREADY SET UP ACROSS THE AREA. LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS CONTINUE TO DEPICT THAT SUFFICIENT LOW LEVEL MOISTURE IS SPREAD ACROSS MOST OF THE AREA DUE TO CONTINUED ONSHORE FLOW. WITH THE ANTICIPATION OF CALM WINDS...EXPECT IFR TO MVFR DUE TO REDUCED VISIBILITIES TO CONTINUE. ANTICIPATE CONDITIONS TO DETERIORATE LOWER TO LIFR DUE TO FOG...WITH THE POTENTIAL FOR LOWERED CIGS AROUND 200FT. RESTRICTIONS WILL LIKELY PERSIST AFTER DAYBREAK...WITH CONDITIONS IMPROVING TO VFR BY LATE MORNING AND LASTING THROUGH THE REMAINDER OF THE VALID PERIOD. EXPECT SOUTHWEST WINDS...BECOMING SOUTH- SOUTHWEST WITH SUSTAINED WINDS AOB 8 KTS BY THE AFTERNOON HOURS...BECOMING LIGHT INTO THE EVENING HOURS. EXTENDED OUTLOOK...A SLIGHT CHANCE OF SHOWERS ON WEDNESDAY ASSOCIATED WITH A COLD FRONT. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 12:30 AM TUESDAY...NO CHANGES TO THE FORECAST WITH LATEST UPDATE. SEAS CONTINUE IN THE 2 FT RANGE...WITH LIGHT AND VARIABLE WINDS. PREVIOUS DISCUSSION FROM 630 PM FOLLOWS... LIGHT SOUTH THROUGH WEST WINDS WILL CONTINUE THROUGH THE NIGHT AS HIGH PRESSURE REMAINS JUST OFFSHORE. SEAS CONSIST ALMOST EXCLUSIVELY OF A 9 SECOND SOUTHEAST SWELL...AVERAGING 2-3 FT. THE ONLY CHANGE TO THE FORECAST IS TO RAISE AIR TEMPERATURE FORECASTS BY UP TO 5 DEGREES ACROSS THE OUTER PORTION OF THE COASTAL WATERS WITH THE MILD SUBTROPICAL AIRMASS. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... DESPITE WINDS BEING LESS THAN 10KT TODAY AND EVEN HAVING SOME VARIABILITY IN DIRECTION THERE IS JUST ENOUGH SWELL ENERGY FOR A 3 FT WAVE OUT AT 41013 AND 41036. WNA AND SWAN SHOW THAT FOR THE MOST PART THE 3 FT SEAS WILL LARGELY REMAIN OUTSIDE OF THE 20NM FORECAST ZONES SAVE FOR ALONG FRYING PAN SHOALS..AND EVEN THAT MIGHT BE A STRETCH. WILL ADVERTISE 2 FT FOR ALL BUT AMZ252 WHERE 2 TO 3 FT WILL STILL BE ADVERTISED. EVE SHIFT MAY BE ABLE TO DROP 3 FT SEAS AFTER MONITORING BUOY DATA. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...WINDS WILL BE LIGHT AT 12 UTC ON TUESDAY AND AS HIGH PRESSURE GIVES AWAY TO FRONTAL BOUNDARY THE WIND DIRECTION WILL SWING TO THE SOUTHWEST AND INCREASE UP TO 10 KNOTS BY THE END OF THE DAY. THE WINDS WILL CONTINUE TO VEER FROM THE SOUTHWEST TO NORTHEAST AS THE FRONT MOVES ACROSS THE COASTAL WATERS. COLD AIR ADVECTION WILL FOLLOW AND WINDS SPEED ARE EXPECTED TO INCREASE TO 20 TO 25 KNOTS FROM THE NORTHEAST LATE WEDNESDAY NIGHT. A SMALL CRAFT ADVISORY MAY BE LIKELY IF THE MODELS CONSISTENCY CONTINUES. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 PM MONDAY...NORTHEAST WINDS INITIALLY FROM 15-20 KNOTS AS HIGH PRESSURE BUILDS DOWN THE EAST COAST. SPEEDS WILL QUICKLY DIMINISH TO LESS THAN TEN KNOTS BY FRIDAY MORNING. WILL PROBABLY HAVE A MARGINAL SMALL CRAFT ADVISORY FOR SEAS AS WELL THURSDAY. WIND SHIFT OCCURS LATE FRIDAY TO SOUTHEAST AS THE AFOREMENTIONED HIGH QUICKLY MOVES OFFSHORE. SPEEDS WILL REMAIN LIGHT AND CONTINUE THROUGH SATURDAY. SIGNIFICANT SEAS WILL DROP TO AROUND TWO FEET. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...REK/MBB SHORT TERM...DRH LONG TERM...SHK AVIATION...SGL MARINE...REK/MBB/SHK/DRH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
929 AM EST TUE DEC 4 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH WEDNESDAY. A COLD FRONT WILL MOVE ACROSS THE AREA WEDNESDAY NIGHT...FOLLOWED BY A WEDGE OF HIGH PRESSURE FROM THE NORTH THROUGH LATE WEEK. A COASTAL TROUGH WILL FORM OFFSHORE ON FRIDAY...THEN SHIFT INLAND OR DISSIPATE EARLY IN THE WEEKEND. ATLANTIC HIGH PRESSURE WILL THEN PREVAIL THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN EXTENSIVE MID-LEVEL CLOUD DECK REMAINS ANCHORED OVER THE AREA THIS MORNING. RAP SOUNDINGS WOULD SUGGEST A GOOD PORTION OF THIS CLOUD DECK WILL THIN AND MIX OUT OVER THE NEXT FEW HOURS AS SURFACE TEMPERATURES SLOWLY WARM. IT LOOKS LIKE SIGNIFICANT CLEARING WILL LIKELY NOT OCCUR UNTIL TEMPERATURES REACH THE UPPER 60S TO LOWER 70S PER THE 04/12Z CHS RAOB. STILL EXPECT A DECENT AMOUNT OF SUN THIS AFTERNOON WITH PARTLY CLOUDY SKIES. HOWEVER... AS TEMPERATURES WARM...EXPECT ANOTHER RATHER ROBUST CUMULUS FIELD TO DEVELOP WITH THE BULK OF THE CLOUD COVER SHIFTING INLAND WITH THE SEA BREEZE. HAVE ADJUSTED THE SKY COVER FORECAST TO MATCH THIS THINKING. TEMPERATURES ARE POISED TO RISE RAPIDLY WHERE INSOLATION INCREASES. HIGHS IN THE MID 70S AWAY FROM THE COAST LOOK REASONABLE...BUT COULD EASILY SEE A FEW UPPER 70S IF CLOUDS BREAK SOONER THAN EXPECTED. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... TONIGHT...ANOTHER ROUND OF FOG EXPECTED BUT COVERAGE AND INTENSITY SHOULD BE LESS THAN PREVIOUS NIGHTS GIVEN THE INCREASE IN HIGH LEVEL MOISTURE AND LOW-LEVEL WINDS AS A COLD FRONT BEGINS TO APPROACH FROM THE WEST. LOWS SHOULD RANGE FROM THE LOWER 50S INLAND TO MID/UPPER 50S AROUND THE COAST. WEDNESDAY AND WEDNESDAY NIGHT...THERE WILL BE TWO DISTINCT TROUGHS IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE THAT WILL INFLUENCE THE WEATHER ACROSS THE REGION. THE FIRST WILL BE A TROUGH WHICH SLOWLY MOVES ACROSS THE NORTHERN GULF OF MEXICO...HELD BACK SOME BY WEAK RIDGING ACROSS THE SOUTHEAST ATLANTIC. THE OTHER TROUGH WILL MOVE ACROSS NEW ENGLAND AND IS DEEPER YET MORE PROGRESSIVE DUE TO THE INFLUENCE OF THE POLAR JET. AT THE SURFACE...THIS TRANSLATES TO MORE OF A BACKDOOR COLD FRONT WHICH DROPS SLOWLY THROUGH THE AREA WEDNESDAY NIGHT. SOMEWHAT ORGANIZED SHOWERS WILL APPROACH FROM THE NORTHWEST ON WEDNESDAY...BUT BECOME CONSIDERABLY MORE DISORGANIZED AS THE FRONT NEARS LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT DUE A WESTERLY FLOW IN PLACE AHEAD OF THE BOUNDARY WHICH SHOULD LIMIT DEEP MOISTURE. THE FORECAST WILL INDICATE A 20-30 PERCENT CHANCE OF SHOWERS ACROSS THE NORTH/NORTHWEST PORTION OF THE FORECAST AREA WEDNESDAY AFTERNOON WITH RAIN-FREE CONDITIONS ELSEWHERE. ON WEDNESDAY NIGHT...THE FORECAST WILL INDICATE A 20-30 PERCENT CHANCE OF SHOWERS AS WELL...WITH THE HIGHEST PROBABILITIES ACROSS SOUTHEAST SOUTH CAROLINA. DESPITE INCREASING CLOUD COVER...THE DOWNSLOPE FLOW AND COMPRESSIONAL HEATING ALONG AND AHEAD OF THE COLD FRONT SHOULD ALLOW TEMPERATURES TO REACH HIGHS IN THE MID 70S AWAY FROM THE COAST ON WEDNESDAY. LOWS WEDNESDAY NIGHT SHOULD BE IN THE LOWER TO MID 50S DUE TO THE EXTENSIVE CLOUD COVER. THURSDAY AND THURSDAY NIGHT...MODELS ARE IN PRETTY GOOD AGREEMENT SHOWING A WEDGE OF HIGH PRESSURE BUILDING SOUTHWARD INTO THE AREA. THERE APPEARS TO BE CONSIDERABLE LOW AND MID LEVEL MOISTURE TRAPPED BENEATH THE INVERSION...WHICH SHOULD TRANSLATE TO MOSTLY CLOUDY SKIES...ESPECIALLY ACROSS SOUTHEAST SOUTH CAROLINA. WEAK ISENTROPIC ASCENT COULD SUPPORT A SLIGHT CHANCE OR LOW CHANCE OF LIGHT SHOWERS JUST ABOUT ANYWHERE. THERE SHOULD BE A LARGE GRADIENT IN HIGH TEMPERATURES...WHICH SHOULD RANGE FROM THE MID TO UPPER 50S IN THE FAR NORTHWEST PORTION OF THE FORECAST AREA TO THE UPPER 60S NEAR THE ALTAMAHA RIVER AND OTHER PORTIONS OF NORTH COASTAL GEORGIA. LOWS THURSDAY NIGHT ARE TRICKY TO FORECAST AS WELL...WITH MID TO UPPER 40S EXPECTED IN MOST AREAS. FRIDAY...AS HIGH PRESSURE CONTINUES TO SHIFT OFFSHORE AWAY FROM THE NEW ENGLAND COAST...A COASTAL TROUGH IS EXPECTED TO DEVELOP JUST OFF THE SOUTHEAST U.S. COAST. THERE COULD BE SOME ISOLATED SHOWERS ALONG THE COAST IN ASSOCIATION WITH THE TROUGH...BUT THE BULK OF THE PRECIPITATION IS EXPECTED TO REMAIN OFFSHORE. AS THE WEDGE SLOWLY ERODES...HIGHS SHOULD REACH THE MID 60S ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND THE UPPER 60S TO NEAR 70 IN SOUTHEAST GEORGIA. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG TERM PERIOD...WHICH WILL FEATURE A BUILDING UPPER LEVEL RIDGE OVER THE SOUTHEAST STATES. AT THE SURFACE...A COASTAL TROUGH IS EXPECTED TO DAMPEN OUT AND/OR SHIFT INLAND FRIDAY NIGHT INTO SATURDAY...WITH ATLANTIC HIGH PRESSURE THEN PREVAILING INTO EARLY NEXT WEEK. A COLD FRONT IS THEN EXPECTED TO ADVANCE TOWARD THE AREA FROM THE NORTHWEST ON TUESDAY. THERE IS A SLIGHT CHANCE FOR SHOWERS AT JUST ABOUT ANY TIME THROUGH MONDAY NIGHT AS A MOIST SOUTHERLY FLOW DEVELOPS OVER THE AREA. THE PROBABILITY FOR SHOWERS WILL INCREASE INTO THE CHANCE CATEGORY ON TUESDAY AHEAD OF THE APPROACHING FRONT. TEMPERATURES WILL BE WELL ABOVE NORMAL UNDER THE INFLUENCE OF THE BUILDING RIDGE. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... EXTENSIVE MID LEVEL CLOUD COVER HAS KEPT FOG FROM FORMING AT THE TERMINALS EARLY THIS MORNING...ALTHOUGH SOME BREAKS IN THE CLOUD COVER NOTED JUST UPSTREAM OF KCHS COULD CAUSE A TEMPORARY/BRIEF DROP IN VISIBILITIES TO MVFR OR LOWER LEVELS FROM ABOUT 13-14Z. FOG IS POSSIBLE ONCE AGAIN TONIGHT...BUT WITH UNCERTAINTY IN EXTENT OF POSSIBLE CLOUD COVER JUST HAVE PREVAILING 6SM IN THE TAF/S AFTER 06Z. IF SKIES ARE RELATIVELY CLEAR...THEN MVFR OR LOWER CONDITIONS ARE POSSIBLE LATE TONIGHT. EXTENDED AVIATION OUTLOOK...LOW CEILINGS POSSIBLE WEDNESDAY NIGHT AS A COLD FRONT MOVES THROUGH...THEN CONTINUING THROUGH THURSDAY NIGHT AS A WEDGE OF HIGH PRESSURE BUILDS FROM THE NORTH. OUTSIDE OF THESE PERIODS...MAINLY VFR. && .MARINE... TODAY AND TONIGHT...ATLANTIC HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH TONIGHT WITH A WEAK PRESSURE PATTERN SUPPORTING WINDS MAINLY 10 KT OR LESS. SEAS DOMINATED BY ABOUT A 9 SECOND EAST SWELL...RANGING FROM 2-3 FT NEARSHORE TO 3-4 FT BEYOND 20 NM. POSSIBLY A BIGGER CONCERN THIS PERIOD WILL BE FOG ACROSS THE COOL NEARSHORE WATERS AS A HUMID AIRMASS REMAINS IN PLACE. WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL GRADUALLY WEAKEN AND DRIFT FARTHER OUT TO SEA WEDNESDAY AS A COLD FRONT APPROACHES FROM THE NORTHWEST AND MOVES THROUGH THE MARINE ZONES WEDNESDAY NIGHT. SURFACE HIGH PRESSURE WILL RAPIDLY BUILD A WEDGE FROM THE NORTH THROUGH THURSDAY NIGHT. SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE ACROSS MOST OF THE COASTAL WATERS WEDNESDAY NIGHT INTO THURSDAY NIGHT...AS THE PRESSURE GRADIENT TIGHTENS AND A NORTHEAST SURGE DEVELOPS BEHIND THE COLD FRONT. THE CENTER OF HIGH PRESSURE WILL THEN MOVE INTO THE ATLANTIC WATERS AND LINGER THROUGH SUNDAY. SEA FOG WILL BE A POSSIBILITY THROUGH WEDNESDAY...AS A MOIST AIR MASS ADVECTS OVER THE COASTAL WATERS. WILL CONTINUE TO MENTION PATCHY FOG ACROSS THE NEAR SHORE COASTAL WATERS AND CHARLESTON HARBOR. IF FOG DOES INDEED FORM...IT COULD BE DENSE AT TIMES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
619 AM EST TUE DEC 4 2012 .SYNOPSIS... ISSUED AT 306 AM EST TUE DEC 4 2012 A BROKEN LINE OF SHOWERS AHEAD OF A COLD FRONT IS MOVING ACROSS LOWER MICHIGAN EARLY THIS MORNING. THE RAIN WILL MOVE OUT OF THE AREA BY LATE MORNING. WE/LL SEE SOME SUNSHINE THIS AFTERNOON BUT TEMPERATURES WILL BE MUCH COOLER THAN YESTERDAY. THERE IS A CHANCE OF MIXED RAIN AND SNOW FROM THURSDAY THROUGH THE WEEKEND. TEMPERATURES WILL BE NEAR NORMAL. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 FORECAST CONCERNS DEAL PCPN TRENDS THIS MORNING. OVERALL...THE FORECAST HASN/T CHANGED MUCH. REGIONAL RADAR SHOWS A BROKEN BAND OF SHOWERS STRETCHING FROM NRN LAKE HURON SWWD TO NEAR ST LOUIS. THIS PCPN IS ALIGNED ALONG THE COLD FRONT WHICH IS PUSHING THROUGH THE CWA ATTM. LATEST IR LOOP SHOWS COOLING CLOUD TOPS OVER ILLINOIS. THIS IS LIKELY IN RESPONSE TO A WAVE ON THE SRN PORTION OF THE FRONT. HRRR SUGGESTS WE/LL SEE A LARGER AREA OF PCPN MOVE INTO THE SRN/SE CWA PRIOR TO SUNRISE AS THE WAVE MOVES NEWD. THIS JUST APPEARS TO BE RAIN...LIGHTNING REMAINS WELL SW OF THE GREAT LAKES. PCPN WILL END FROM NW TO SE THIS AFTERNOON AS THE WAVE MOVES MOVES THROUGH. A SECONDARY COLD FRONT WILL MOVE SEWD THROUGH LOWER MICHIGAN TONIGHT. WE MAY BRIEFLY SEE A FEW SHSN DEVELOP ALONG THE LAKE SHORE NORTH OF HOLLAND BUT THEY WON/T AMOUNT TO MUCH AND WILL QUICKLY FADE BY WEDNESDAY MORNING AS CORE OF THE COLD AIR MOVES EAST. HIGH PRESSURE WILL SETTLE OVER THE CWA WEDNESDAY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 CHALLENGING FORECAST IN THE EXTENDED AS MODEL CONSISTENCY HAS BEEN POOR THE LAST COUPLE DAYS HANDLING THE DETAILS OF AN INVERTED TROUGH/SFC WAVE MOVING ALONG THE FRONT STALLED ACROSS THE OHIO VALLEY...AND A MORE SIGNIFICANT STORM EARLY NEXT WEEK. WENT WITH LOW CHANCE OR SLIGHT CHANCE POPS EARLY IN THE PERIOD WITH LOW CONFIDENCE ON DETAILS OF WHEN AND WHERE BEST CHANCES FOR PRECIP WITH BE. P-TYPE IS ALSO A TOUGH CALL AS THERMAL PROFILES SUGGEST MIX NORTH AND RAIN SOUTH. A HIGHER IMPACT EVENT IS EXPECTED NEXT WEEK AS STRONG UPPER TROUGH MOVES INTO THE ROCKIES WITH SFC LOW FORMING OVER THE PLAINS AND HEADING FOR LOWER MICHIGAN. AGAIN CONFIDENCE IS LOW ON TIMING DUE TO MODEL DIFFERENCES AND INCONSISTENCY...BUT A MIXED PRECIP TO RAIN THEN OVER TO SNOW SCENARIO IS POSSIBLE EARLY NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 618 AM EST TUE DEC 4 2012 RAIN WILL CONTINUE FROM AZO TO LAN THIS MORNING WITH SOME MVFR CONDITIONS PERSISTING THERE UNTIL AROUND 16Z. JXN WILL SEE SOME MVFR AND EVEN IFR CONDITIONS AS THE RAIN WILL BE SLOW TO MOVE EAST. ALL LOCATIONS SHOULD BE VFR BY THIS AFTERNOON AND EVENING. && .MARINE... ISSUED AT 306 AM EST TUE DEC 4 2012 COLD ADVECTION WILL INCREASE WAVE HEIGHTS TODAY INTO WEDNESDAY. WE EXTENDED THE SCA THROUGH THE AFTERNOON WEDNESDAY. && .HYDROLOGY... ISSUED AT 306 AM EST TUE DEC 4 2012 NO HYDRO ISSUES THIS MORNING QPF LESS THAN A QUARTER INCH IS EXPECTED FROM SHOWERS ALONG THE COLD FRONT THIS MORNING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LMZ844>849. && $$ SYNOPSIS...93 SHORT TERM...93 LONG TERM...OSTUNO AVIATION...OSTUNO HYDROLOGY...93 MARINE...93
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
350 PM MST TUE DEC 4 2012 .SHORT TERM...MODERATE WEST TO NORTHWEST FLOW ALOFT ACROSS REGION WITH SHORT WAVE RIDGE OVER GREAT BASIN. WEAK STABLE LAYER CURRENTLY AT MOUNTAIN TOP WITH RADAR SHOWING SOME SIGNS OF A MOUNTAIN WAVE. WINDS ALOFT NOT VERY STRONG WITH CROSS MOUNTAIN FLOW 30-35 KTS AT MOUNTAIN TOP. SOME RECENT GUSTS TO 40 MPH BEING REPORTED IN THE ESTES PARK AREA...BUT APPEAR LOCALIZED AND PERHAPS TERRAIN DRIVEN. LATEST RUC CROSS SECTIONS INDICATE WINDS ALOFT GRADUALLY DECREASING AFTER 02Z WITH CROSS MOUNTAIN WINDS AROUND 25 KTS NEAR RIDGE TOP AND ALONG HIGHER FOOTHILLS BY 06Z. THUS SHOULD SEE WIND GUSTS GRADUALLY DECREASE DURING THE EVENING THOUGH THE TERRAIN MAY KEEP THINGS A BIT GUSTY. SHOULD ALSO SEE A GRADUAL INCREASE IN HUMIDITY AS TEMPERATURES COOL. LATEST SATELLITE LOOPS SHOW CLOUDS HAVE THINNED ACROSS THE AREA WITH REMNANTS OF WAVE CLOUD EAST OF URBAN CORRIDOR. MORE MOISTURE UPSTREAM...WITH INCREASING HIGH LEVEL MOISTURE OVERNIGHT. WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING THE WAVE CLOUD REDEVELOPS ALONG FOOTHILLS AFTER 08Z. ON WEDNESDAY...FLOW ALOFT BECOMES WESTERLY AS RIDGE MOVES SOUTH AND EAST OF COLORADO. CROSS SECTIONS SHOW MOISTURE INCREASING ACROSS THE AREA WITH SOME LOWERING OF THE MOISTURE ACROSS MOUNTAINS DURING THE MORNING...MAINLY NORTH OF INTERSTATE 70. MAY BE ENOUGH OROGRAPHICS TO GENERATE SOME SHOWERS ACROSS ZONE 31. OTHERWISE WINDS ALOFT TO INCREASE WITH CROSS MOUNTAIN FLOW AROUND 40 KTS AT MOUNTAIN TOP BY 18Z. THUS WINDS TO BE GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS WITH LOCAL GUSTS AROUND 45 MPH POSSIBLE DURING THE AFTERNOON. THE GUSTY WINDS WILL KEEP THE FIRE DANGER ELEVATED ALONG THE FOOTHILLS...BUT HUMIDITY SHOULD REMAIN ABOVE CRITICAL FIRE WEATHER THRESHOLDS. TEMPERATURE AND THICKNESS PROGS AS WELL AS GUIDANCE SHOWING HIGHS IN THE 60S ACROSS THE PLAINS. THIS LOOKING REASONABLE. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE...ONLY MINOR CHANGES NEEDED. .LONG TERM...WESTERLY FLOW ALOFT WILL PREVAIL WEDNESDAY NIGHT AND THURSDAY. WINDS WILL INCREASE WEDNESDAY NIGHT OVER THE MOUNTAINS AND FOOTHILLS AS A COLD FRONT MOVES THROUGH THE STATE. A WEAK SHORT WAVE TROUGH MAY BRING LIGHT SNOW TO THE MOUNTAINS AND PERHAPS SOME LIGHT RAIN OVER EASTERN COLORADO THURSDAY. THE WESTERLY JET WILL SINK SOUTH AS AN UPPER LEVEL TROUGH MOVES ONTO THE PACIFIC NORTHWEST COAST. THIS WILL BRING COOLER CONDITIONS ON FRIDAY WITH HIGHS IN THE 40S. ANOTHER WEAK DISTURBANCE EMBEDDED IN THE FLOW ALOFT WILL BRING ANOTHER CHANCE FOR LIGHT PRECIPITATION. THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL DIVE SOUTH ACROSS THE GREAT BASIN SATURDAY AND END UP OVER THE SOUTHERN ROCKIES SUNDAY. THIS WILL PUSH A STRONG COLD FRONT ACROSS COLORADO. STILL SOME DIFFERENCE ON TRACK AND TIMING...BUT WILL BE ENOUGH ENERGY TO BRING A PERIOD OF SNOW TO THE AREA. BIGGEST QUESTIONS ARE WHEN AND HOW MUCH. APPEARS THE SNOW WILL BEGIN SOMETIME SATURDAY AND COME TO AN END EARLY SUNDAY. MAY SEE SOME HEAVIER SNOW BANDS SATURDAY AS THE JEST SINKS SOUTH ACROSS COLORADO. WILL CENTER THE HIGHEST POPS AROUND SATURDAY NIGHT WHEN THE BEST CHANCE WILL BE ACCORDING TO THE MODELS. COLD AIR WILL MOVE IN WITH THIS SYSTEM AND HIGHS WILL LIKELY REMAIN BELOW FREEZING SUNDAY AND EARLY NEXT WEEK. NORTHWEST FLOW MAY BRING LIGHT OROGRAPHIC SNOW EARLY NEXT WEEK...OTHERWISE JUST DRY AND COOL CONDITIONS ARE EXPECTED FOR MONDAY AND TUESDAY. && .AVIATION...LIGHT EASTERLY WINDS AT APA AND DEN TO WEAK AND BECOME SOUTHERLY AS DRAINAGE PATTERN DEVELOPS. WINDS TO REMAIN WESTERLY AT BJC. ON WEDNESDAY...WINDS TO BECOME NORTHWEST AFTER 18Z WITH SPEEDS AROUND 8 KTS. HIGH LEVEL MOISTURE TO INCREASE AFTER 06Z WITH THE POTENTIAL FOR A WAVE CLOUD ALONG FOOTHILLS BY 10Z. VFR TO CONTINUE WITH CEILINGS UNLIMITED. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....MEIER AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
936 AM MST TUE DEC 4 2012 .UPDATE... && .SHORT TERM...CURRENT FORECASTS STILL ON TRACK. WINDS TO BE ON THE INCREASE DURING THE AFTERNOON...WITH BOTH NAM AND RUC CROSS SECTIONS INDICATING CROSS MOUNTAIN FLOW AROUND 35 KTS AT MOUNTAIN TOP BY 00Z. WINDS LOOKING MARGINAL FOR RED FLAG CONDITIONS DESPITE THE LOW HUMIDITY. A FEW AREAS ALONG FOOTHILLS MAY REACH CRITERIA FOR A SHORT TIME...MAINLY LOCATIONS WHERE TERRAIN WILL AID IN FUNNELLING THE WINDS. STILL SOME THINNING OF WAVE CLOUD THROUGH THE AFTERNOON...THEN REDEVELOPING OVERNIGHT WITH ARRIVAL OF DEEPER MOISTURE. .AVIATION...CURRENT TAF TRENDS LOOK REASONABLE...WILL CONTINUE FOR THE UPCOMING ISSUANCE. && .PREV DISCUSSION... /ISSUED 352 AM MST TUE DEC 4 2012/ SHORT TERM...CLOUDS WILL INCREASE FROM WEST TO EAST DURING THE DAY AS WARMER AIR SPREADS OVER THE AREA. DESPITE THE HIGH CLOUDINESS...THERE IS STILL SOME PRETTY DRY AIR AT LOW LEVELS. DEW POINTS HAVE COME UP IN THE MOUNTAINS OVERNIGHT...MODEL GUIDANCE SHOWS SURFACE DEW POINTS DROPPING AGAIN WITH MIXING DURING THE DAY...BUT THEN RISING LATER IN THE DAY AS LOW LEVEL MOISTURE FINALLY ARRIVES. I AM RATHER PESSIMISTIC ABOUT THE TIMING OF THIS AND WILL HEDGE TOWARD LOWER VALUES THIS AFTERNOON. WINDS ALSO WILL BE COMING UP LATE IN THE DAY...BUT FLOW ALOFT IS NOT THAT STRONG WITH 20 KNOTS INCREASING TO 35 KNOTS AT 600 MB. ALSO A WEAK STABLE LAYER...SO NOT EXPECTING WAVE AMPLIFICATION BUT THERE WILL BE SOME STRONGER FLOW SPILLING DOWN THE HIGHER EAST SLOPES OF THE FRONT RANGE. ALL IN ALL NOT MUCH OF A HIGH WIND THREAT AND MARGINAL ON WIND AND ESPECIALLY HUMIDITY FOR A RED FLAG WARNING IN ZONE 35 ONLY...SO NO HIGHLIGHTS. MODELS SHOW SOME THINNING OF THE CLOUDS THIS EVENING THEN DEEPER MOISTURE ARRIVING INTO THE MOUNTAINS LATE TONIGHT...THOUGH THE GFS HOLDS THE BEST MOISTURE UP IN WYOMING. THIS LOOKS REASONABLE AS THE SATELLITE PICTURES SEEM TO SHOW THESE FEATURES...SOME LOWER CLOUDS IN NORTHERN NEVADA SO THIS MAY CLIP THE PARK RANGE BUT WILL LEAVE THE CHANCE OF SNOW FOR DAYTIME ON WEDNESDAY. FORECAST TEMPS ARE NEAR GUIDANCE AND LOOK PRETTY GOOD. LONG TERM...ZONAL FLOW WILL BE OVER THE AREA ON WED WITH QUITE A BIT OF MID AND HIGH LEVEL MOISTURE STREAMING ACROSS. COULD SEE A SLIGHT CHC OF SHOWERS IN ZN 31 OTHERWISE WILL KEEP FCST DRY. HIGHS ON WED WILL BE MILD WITH READINGS MAINLY IN THE 65 TO 70 DEGREE RANGE ACROSS NERN CO. WINDS WILL BE GUSTY AT TIMES IN THE MTNS AND NRN FOOTHILLS BUT SPEEDS SHOULD REMAIN BLO WARNING CRITERIA. FOR WED NIGHT INTO THU MOISTURE WILL DEEPEN IN THE MTNS WITH SLIGHTLY BETTER LAPSE RATES AS A WEAK UPPER LEVEL TROUGH MOVES ACROSS. THUS SHOULD SEE A BETTER CHC OF SNOW IN THE MTNS ALTHOUGH ACCUMULATIONS WILL STILL BE ON THE LIGHT SIDE. OVER NERN CO A WK CDFNT WILL AFFECT THE AREA HOWEVER CROSS-SECTIONS SHOW ONLY WEAK UPSLOPE FLOW. WILL LEAVE IN A SLIGHT CHANCE OF PCPN DUE TO PASSAGE OF WK UPPER LEVEL TROUGH. SOUNDING DATA SHOWS SNOW LEVEL MAINLY ABOVE 7000 FEET SO WILL KEEP PCPN IN THE FORM OF RAIN WITH A MIXTURE IN THE FOOTHILLS. HIGHS ON THU WILL BE COOLER WITH READINGS IN THE 50S ACROSS NERN CO. WINDS WILL REMAIN GUSTY IN THE MTNS AND FOOTHILLS WED NIGHT INTO THU MORNING HOWEVER ONCE AGAIN SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. ON FRI LATEST DATA SHOWS A STRONGER JET MOVING INTO NRN IN WNW FLOW ALOFT WITH ANOTHER WK UPPER LVL TROUGH. THUS COULD SEE ANOTHER CHC OF SNOW IN THE MTNS WITH GUSTY WINDS. LAPSE RATES WILL IMPROVE WITH THIS SECOND FEATURE SO ACCUMULATIONS MAY END UP BEING BETTER WITH SOME ENHANCEMENT DUE TO POSITION OF UPPER LEVEL JET. OVER NERN CO LATEST GFS SHOWS ANOTHER FNT MOVING INTO NERN CO BY MIDDAY WITH SOME WK UPSLOPE FLOW WHILE THE ECMWF DOES NOT SHOW A THIS FNT COMING IN UNTIL FRI EVENING. AM A LITTLE CONCERNED WITH POSITION OF UPPER LVL JET AND DECENT LAPSE RATES ACROSS NERN CO FRI AFTN INTO FRI EVENING. IF ENOUGH MOISTURE IS PRESENT COULD SEE AT LEAST A SLIGHT CHC OF SHOWERS EITHER FRI AFTN OR FRI NIGHT DEPENDING ON TIMING OF FNT. AS FOR HIGHS 850-700 MB TEMPS ARE COOLER ON FRI SO WILL KEEP READINGS IN THE 40S ACROSS NERN CO. FOR THE WEEKEND THE ECMWF AND GFS SHOW A STRONG UPPER LEVEL TROUGH MOVING SE ACROSS THE AREA SAT NIGHT THROUGH SUN NIGHT WITH AN ASSOCIATED STG CDFNT. AT THIS TIME IT APPEARS THE BEST CHC OF PCPN WILL BE FROM SAT NIGHT THRU SUN. SOME HEAVIER SNOWFALL MAY OCCUR SAT NIGHT INTO SUN MORNING IN THE FOOTHILLS AND ALONG THE FRONT RANGE DUE TO INCREASING UPSLOPE FLOW AND POSITION OF UPPER LEVEL JET WHICH MAY LEAD TO BANDED PCPN. MTNS SHOULD SEE SOME SNOW AS WELL WITH EAST FACING SLOPES HAVING THE HIGHEST ACCUMULATIONS. AS FOR HIGHS AHEAD OF THE STG CDFNT READINGS WILL BE IN THE 40S ON SAT OVER NERN CO WHILE ON SUN READINGS MAY STAY IN THE 20S. BY SUN NIGHT AND MON THE UPPER LEVEL TROUGH WILL MOVE SE OF THE AREA WITH SNOW LIKELY ENDING SUN EVENING FOLLOWED BY DRY CONDITIONS ON MON. TEMPS ON MON WILL REMAIN COLD WITH READINGS STAYING IN THE 20S OVER NERN CO. AVIATION...VFR CONDITIONS AND LIGHT WINDS TODAY...SHOULD KEEP A SOUTHERLY COMPONENT AT KDEN/KAPA WITH EASTERLIES DEVELOPING DURING THE DAY AT KBJC. BACK TO S/W DRAINAGE WINDS THIS EVENING. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RPK AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
252 PM EST TUE DEC 4 2012 .SHORT TERM /TONIGHT THROUGH THURSDAY/... MAIN FORECAST PROBLEM THROUGH WEDNESDAY IS LIKELIHOOD FOR MEASURABLE PRECIP. SHORT WAVE CURRENTLY LOCATED OVER SE OK/NRN TX ON WV IMAGERY TRACKING EAST WITH CONSIDERABLE AMOUNT OF DEEP CONVECTION OCCURRING AHEAD OF THE WAVE OVER THE LOWER MS VALLEY. MODELS HAVE VERY GOOD AGREEMENT ON TIMING OF WAVE AND ASSOCIATED FRONT MOVING INTO THE FAR NORTH LATE TONIGHT. MODELS ALSO IN STRONG AGREEMENT THAT VERTICAL LIFT WILL WEAKEN TONIGHT AND WEDNESDAY WITH MUCH LOWER PRECIP AMOUNTS AS THE SYSTEM MOVES INTO THE STATE. ALWAYS A CHALLENGE TO FORECAST POPS IN THIS SITUATION AS WILL LIKELY SEE SCT LIGHT SHOWERS ACROSS NORTHERN 3/4THS OF CWA BUT NOT CONFIDENT THAT ALL THESE SHOWERS WILL PRODUCE MEASURABLE RAINFALL. HAVE KEPT POPS LATE TONIGHT AND WED CONFINED TO LKLY CATEGORY OVER AREAS NORTH OF ATL METRO AND 40-60 OVER METRO AND MUCH OF MIDDLE GA. NEAR-TERM MODELS INCLUDING RADAR ASSIMILATING MODELS SUCH AS THE HRRR ARE INDICATING BEST CHC FOR RAIN IN THE ATL METRO AROUND 6-8AM WITH LINGERING CHC OF SCT LIGHT SHOWERS DURING THE DAY. USED MAV/MET BLEND FOR TEMPS WITH A SLIGHT UPWARD ADJUSTMENT FOR MIN TEMPS TONIGHT. BY WED...SUBSIDENCE BEHIND STRONG WAVE OVER THE NORTHEAST CONUS YIELDS A EXPANSIVE 1035MB SFC HIGH OVER THE MIDWEST WHICH IS PROGGED TO SPILL OVER AND DAM UP ALONG THE APPALACHIANS. SIGNIFICANT WEDGE EVENT SHOULD RESULT BUT AS MENTIONED EARLIER...WE ARE FORTUNATE THAT THE SOURCE AIRMASS FOR THIS HIGH IS NOT ARCTIC OR THAT COLD. OTHERWISE WE MIGHT BE IN A WORLD OF HURT. OTHER THAN SOME COOL EAST WINDS AND SOME PATCHY LIGHT RAIN AND FAIRLY WIDESPREAD CLOUDS... SHOULD NOT BE TOO BAD FOR DECEMBER. SNELSON .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... OVERALL...PREVIOUS FORECAST LOOKS TO BE ON TRACK. HAVE CONTINUED WITH SLIGHT CHANCE POPS AS THE WEDGE REMAINS IN PLACE THROUGH LATE WEEK WITH MODELS STILL INDICATING ISENTROPIC LIFT AND UPSLOPE FLOW WILL SUPPORT LIGHT RAIN. MODEL GUIDANCE HAVE WARMED SLIGHTLY DURING THE CAD EVENT...AND HAVE INCREASED MORNING LOW TEMPERATURES SLIGHTLY FOR BETTER CONSISTENCY WITH THE SURROUNDING OFFICES. FOR NOW...HAVE MADE A FEW VERY MINOR TWEAKS TO HIGH TEMPERATURE...BUT OVERALL THINK THE MODELS ARE TOO WARM. THERE IS STILL ENOUGH UNCERTAINTY WITH LATE WEEKEND AND EARLY WEEK MODEL SOLUTIONS THAT HAVE OPTED NOT TO MAKE ANY SIGNIFICANT CHANGES AT THIS TIME. HAVE INCLUDED THE PREVIOUS DISCUSSION BELOW. 31 ISSUED 356 AM EST TUE DEC 4 2012/ FRONT IMPACTING NORTH GEORGIA DURING THE SHORT TERM WILL BRIEFLY STALL OUT ACROSS CENTRAL GEORGIA WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS BOUNDARY WILL PUSH FARTHER SOUTH AND WEST AS A WEDGE FRONT ON THURSDAY DUE TO HYBRID CAD FROM A 1027 MB PARENT HIGH OFF THE MID- ATLANTIC COAST. HAVE INCLUDED SLIGHT POPS FOR SHOWERS AS THIS BOUNDARY INTERACTS WITH OVERRUNNING MOISTURE FROM THE SOUTH. GUIDANCE SUGGESTS CONTINUED ISENTROPIC UPGLIDE ACROSS MUCH OF THE AREA THROUGH FRIDAY SO HAVE KEPT SLIGHT CHANCE POPS FOR SHOWERS FOR THE MAJORITY OF THE CWA AND MOSTLY CLOUDY SKIES DURING THIS PERIOD. ANY ENHANCED SOLAR SHELTERING ACROSS THE CAD DOME MAY REINFORCE THE WEDGE AND LEAD TO LATER EROSION THAN WHAT GUIDANCE SUGGESTS... POSSIBLY LINGERING INTO THE WEEKEND. THIS WILL NEED TO BE MONITORED CLOSER AS THIS FEATURE GETS INCLUDED IN THE SHORT TERM MODELS. BROAD SW FLOW ALOFT SETS UP FOR THE WEEKEND AND A STATIONARY FRONT LOOKS TO BECOME SITUATED NW OF THE AREA ACROSS THE TN AND OHIO RIVER VALLEYS. THE GFS AND ECMWF DIFFER GREATLY IN THE STRENGTH OF THE BAROCLINITY AND EXPANSE OF THE MOISTURE FIELD WITH THIS FEATURE...THOUGH SOME SHOWER DEVELOPMENT IS POSSIBLE ACROSS NORTH GEORGIA IF ENOUGH MOISTURE EXISTS WITH SOME OROGRAPHIC ENHANCEMENT DUE TO SOUTHERLY/SOUTHWESTERLY LOW LEVEL FLOW. HAVE THEREFORE KEPT SLIGHT TO LOW END CHANCE POPS FOR SHOWERS ACROSS THE NORTHERN PORTION THROUGH THE WEEKEND. THE LATEST RUNS OF THE GFS AND ECMWF ARE IN DECENT AGREEMENT WITH THE NEXT SIGNIFICANT PIECE OF ENERGY SWINGING ACROSS THE SOUTHWEST CONUS AS AN UPPER CUTOFF LOW BY SUNDAY INTO MONDAY...THEN LIFTING NORTHEASTWARD ACROSS THE CENTRAL PLAINS BY MONDAY NIGHT INTO TUESDAY. A STRONG COLD FRONT ASSOCIATED WITH THE PHASED SFC LOW PRESSURE SYSTEM MAY APPROACH THE FORECAST AREA FROM THE WEST BY TUESDAY...HOWEVER THIS IS JUST BEYOND THE END OF THE FORECAST PERIOD AND WILL ADJUST AS NECESSARY IN FUTURE UPDATES. FORECAST INSTABILITY IS TOO LOW TO INCLUDE ANY THUNDER CHANCES IN THE LONG TERM...THOUGH THE BEST SHOT LOOKS TO BE WITH POTENTIAL CFP NEAR THE END OF THE FORECAST PERIOD EARLY NEXT WEEK. BAKER && .AVIATION... 18Z UPDATE... PRIMARY CONCERN IS CHC FOR IFR CIGS AND SHRA LATE TONIGHT AND WED MORNING. UNUSUAL WARM MOIST PATTERN WILL CONTINUE WITH CLOUDS LIKELY TO PERSIST AHEAD OF FRONT. NOT A PATTERN FOR WIDESPREAD PRECIP. SCT SHRA WILL REMAIN WEST OF MOST TAF SITES UNTIL 12Z. COULD SEE IFR CIGS ASSOCD WITH PRECIP AND SOME RADIATIONAL COOLING ABOVE MOIST LOW LEVELS PERSIST THROUGH 16Z OR SO. INSTABILITY WILL BE NEAR ZERO SO NO THREAT FOR TSRA. FRONT WILL BECOME STATIONARY ACROSS THE STATE WEDNESDAY SO SW TO WEST SFC WINDS WILL NOT BECOME NW. //ATL CONFIDENCE...18Z UPDATE... MEDIUM CONFIDENCE ON IFR CIGS AND PRECIP PROBS WED MORNING. HIGH CONFIDENCE ON ALL OTHER ELEMENTS. SNELSON && .PRELIMINARY POINT TEMPS/POPS... ATHENS 53 68 50 57 / 40 50 30 20 ATLANTA 56 67 51 60 / 50 60 20 20 BLAIRSVILLE 51 63 44 55 / 60 60 20 20 CARTERSVILLE 53 66 48 61 / 60 60 20 20 COLUMBUS 55 74 54 69 / 30 30 10 20 GAINESVILLE 54 65 49 56 / 50 60 30 20 MACON 52 74 51 65 / 20 20 20 20 ROME 52 67 47 62 / 60 60 20 20 PEACHTREE CITY 51 67 48 62 / 50 60 20 20 VIDALIA 53 75 54 67 / 10 20 10 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SNELSON LONG TERM....31 AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1249 PM EST TUE DEC 4 2012 .SYNOPSIS... ISSUED AT 306 AM EST TUE DEC 4 2012 A BROKEN LINE OF SHOWERS AHEAD OF A COLD FRONT IS MOVING ACROSS LOWER MICHIGAN EARLY THIS MORNING. THE RAIN WILL MOVE OUT OF THE AREA BY LATE MORNING. WE/LL SEE SOME SUNSHINE THIS AFTERNOON BUT TEMPERATURES WILL BE MUCH COOLER THAN YESTERDAY. THERE IS A CHANCE OF MIXED RAIN AND SNOW FROM THURSDAY THROUGH THE WEEKEND. TEMPERATURES WILL BE NEAR NORMAL. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 FORECAST CONCERNS DEAL PCPN TRENDS THIS MORNING. OVERALL...THE FORECAST HASN/T CHANGED MUCH. REGIONAL RADAR SHOWS A BROKEN BAND OF SHOWERS STRETCHING FROM NRN LAKE HURON SWWD TO NEAR ST LOUIS. THIS PCPN IS ALIGNED ALONG THE COLD FRONT WHICH IS PUSHING THROUGH THE CWA ATTM. LATEST IR LOOP SHOWS COOLING CLOUD TOPS OVER ILLINOIS. THIS IS LIKELY IN RESPONSE TO A WAVE ON THE SRN PORTION OF THE FRONT. HRRR SUGGESTS WE/LL SEE A LARGER AREA OF PCPN MOVE INTO THE SRN/SE CWA PRIOR TO SUNRISE AS THE WAVE MOVES NEWD. THIS JUST APPEARS TO BE RAIN...LIGHTNING REMAINS WELL SW OF THE GREAT LAKES. PCPN WILL END FROM NW TO SE THIS AFTERNOON AS THE WAVE MOVES MOVES THROUGH. A SECONDARY COLD FRONT WILL MOVE SEWD THROUGH LOWER MICHIGAN TONIGHT. WE MAY BRIEFLY SEE A FEW SHSN DEVELOP ALONG THE LAKE SHORE NORTH OF HOLLAND BUT THEY WON/T AMOUNT TO MUCH AND WILL QUICKLY FADE BY WEDNESDAY MORNING AS CORE OF THE COLD AIR MOVES EAST. HIGH PRESSURE WILL SETTLE OVER THE CWA WEDNESDAY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 306 AM EST TUE DEC 4 2012 CHALLENGING FORECAST IN THE EXTENDED AS MODEL CONSISTENCY HAS BEEN POOR THE LAST COUPLE DAYS HANDLING THE DETAILS OF AN INVERTED TROUGH/SFC WAVE MOVING ALONG THE FRONT STALLED ACROSS THE OHIO VALLEY...AND A MORE SIGNIFICANT STORM EARLY NEXT WEEK. WENT WITH LOW CHANCE OR SLIGHT CHANCE POPS EARLY IN THE PERIOD WITH LOW CONFIDENCE ON DETAILS OF WHEN AND WHERE BEST CHANCES FOR PRECIP WITH BE. P-TYPE IS ALSO A TOUGH CALL AS THERMAL PROFILES SUGGEST MIX NORTH AND RAIN SOUTH. A HIGHER IMPACT EVENT IS EXPECTED NEXT WEEK AS STRONG UPPER TROUGH MOVES INTO THE ROCKIES WITH SFC LOW FORMING OVER THE PLAINS AND HEADING FOR LOWER MICHIGAN. AGAIN CONFIDENCE IS LOW ON TIMING DUE TO MODEL DIFFERENCES AND INCONSISTENCY...BUT A MIXED PRECIP TO RAIN THEN OVER TO SNOW SCENARIO IS POSSIBLE EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1249 PM EST TUE DEC 4 2012 VFR CONDITIONS PREVAIL ACROSS SOUTHWEST LOWER MICHIGAN AS OF 1730Z. THE COLD FRONT AND RAIN ASSOCIATED WITH IT ARE NOW OFF TO THE EAST AND SOUTH OF THE AREA. DRIER AIR IS WORKING INTO SOUTHWEST LOWER MICHIGAN. VFR CONDITIONS ARE EXPECTED INTO THE EVENING HOURS AS THE MID AND HIGH CLOUDS SLOWLY CLEAR TO THE SOUTHEAST. FOCUS SHIFTS TOWARD COLDER AIR SLIDING IN ON NORTHWEST WINDS AND THE CHANCE FOR MVFR CLOUDS DEVELOPING TONIGHT AS THE COLD AIR RIDES OVER LAKE MICHIGAN. FEEL LAKE CLOUDS WILL DEVELOP AND PUSH INTO KMKG THIS EVENING AND SWEEP SOUTH AND EAST WITH TIME. BY 07Z OR SO...THE MVFR STRATOCUMULUS DECK SHOULD BE OVER ALL THE TAF SITES. CEILINGS OVER AROUND 3000FT WILL PERSIST INTO THE MIDDAY HOURS OF WEDNESDAY. AT THIS POINT THE MOISTURE LOOKS TO SHALLOW FOR ANY SNOW SHOWER ACTIVITY. && .MARINE... ISSUED AT 306 AM EST TUE DEC 4 2012 COLD ADVECTION WILL INCREASE WAVE HEIGHTS TODAY INTO WEDNESDAY. WE EXTENDED THE SCA THROUGH THE AFTERNOON WEDNESDAY. && .HYDROLOGY... ISSUED AT 306 AM EST TUE DEC 4 2012 NO HYDRO ISSUES THIS MORNING QPF LESS THAN A QUARTER INCH IS EXPECTED FROM SHOWERS ALONG THE COLD FRONT THIS MORNING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LMZ844>849. && $$ SYNOPSIS...93 SHORT TERM...93 LONG TERM...OSTUNO AVIATION...DUKE HYDROLOGY...93 MARINE...93
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
ISSUED BY NATIONAL WEATHER SERVICE NORTH PLATTE NE 1042 AM MST TUE DEC 4 2012 && .AVIATION... VFR CONDITIONS EXPECTED THROUGH THE 18Z TAF FORECAST CYCLE. HOWEVER...GUSTY SOUTHWEST /210-240/ SFC WINDS WILL CONTINUE AT KGCC WITH GUST POTENTIAL AT OR ABOVE 20KTS THIS AFTERNOON. MODEL GUIDANCE INDICATES A BRIEF PERIOD OF LIGHTER WINDS AT KGCC THIS EVENING...BUT INCREASE ONCE AGAIN OVERNIGHT WITH 15KTS OR GREATER AT THE TERMINAL. AT KRAP...LESSER WINDS EXPECTED....WITH SOUTHERLY PEAK GUST POTENTIAL AT OR SLIGHTLY ABOVE 15 KTS THIS AFTERNOON...THEN LIGHT AND VARIABLE OVERNIGHT. && .UPDATE...MADE SOME MINOR CHANGES TO THE ONGOING FCST...MAINLY TO DELAY THE ONSET OF CLOUDINESS THIS AFTERNOON BASED ON UPSTREAM SATELLITE IMAGERY. BASED ON THE 12Z UNR RAOB AND MIXED H85 TEMPS...HIGHS THIS AFTERNOON SHOULD BE AROUND 50 FOR RAPID CITY. H85 TEMPS IN THE LATEST RUC AND NAM SOLNS INCREASE AROUND A DEGREE OR TWO THIS AFTERNOON...SO HIGHS IN THE LOWER 50S SEEM PLAUSIBLE FOR RAPID CITY. WITH HIGH CLOUDINESS HOLDING OFF UNTIL THE MID AFTERNOON HOURS...ITS EFFECTS ON HIGHS ARE EXPECTED TO BE NEGLIGIBLE SO MIXED TEMPS WILL BE UTILIZED IN THE FCST. WINDS THIS AFTERNOON WILL SHIFT TO THE SOUTH AS HIGH PRESSURE BUILDS INTO EASTERN NORTH DAKOTA AND NORTHWESTERN MN. PREV DISCUSSION... /ISSUED 316 AM MST MON DEC 3 2012/ DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS HIGH PRESSURE OVER THE CENTRAL ROCKIES. LOW PRESSURE IS OVER SOUTHWESTERN ONTARIO...WITH A COLD FRONT STRETCHING ACROSS NORTHERN MN...ND...AND NORTHEASTERN MT. UPPER LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE NORTHERN ROCKIES...WITH LOW REMAINING OFF THE PACIFIC NW COAST. SKIES ARE MOSTLY CLEAR ACROSS THE AREA WITH TEMPS IN THE MID 20S TO MID 30S. WINDS ARE LIGHT FROM THE WEST TO SOUTHWEST. MILD AND DRY CONDITIONS WILL CONTINUE THROUGH WEDNESDAY...WITH HIGHS 20 TO 25 DEGREES ABOVE AVERAGE ON WEDNESDAY. A COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY NIGHT...BRINGING TEMPS BACK TO MORE NORMAL LEVELS FOR THE END OF THE WEEK. A BROAD UPPER TROF WILL THEN SLOWLY SETTLE OVER THE AREA LATE IN THE WEEK..,BRINGING UNSETTLED WEATHER THROUGH THE WEEKEND AND KEEPING TEMPS ON THE COLD SIDE. FOR TODAY...SKIES WILL START OFF MAINLY SUNNY...WITH INCREASING MID AND HIGH CLOUDINESS FROM WEST TO EAST DURING THE DAY. THE WEAK COLD FRONT TO THE NORTH WILL SINK SLOWLY SOUTH AND WEST DURING THE DAY...STALLING OUT ALONG OR JUST EAST OF THE BLACK HILLS BY LATE TODAY. HIGHS WILL RANGE FROM THE MID 40S OVER THE HIGHER BLACK HILLS AND THE LEMMON AREA...TO THE MID 50S OVER MUCH OF SOUTHWESTERN AND SOUTH CENTRAL SD. SOUTHWESTERLY WINDS WILL INCREASE ACROSS NORTHEASTERN WY AND PORTIONS OF THE BLACK HILLS...BECOMING BREEZY AT TIMES ACROSS CAMPBELL CO...ESPECIALLY SOUTHERN CAMPBELL CO. EAST OF THE BLACK HILLS...WINDS WILL SWITCH OVER TO THE SOUTHEAST DURING THE AFTERNOON. SKIES WILL BE PARTLY CLOUDY IN GENERAL TONIGHT WITH LOWS MOSTLY IN THE 30S. WINDS WILL REMAIN BREEZY AT TIMES ACROSS PORTIONS OF NORTHEASTERN WY AND THE BLACK HILLS. WEAK RIDGE TO THE WEST WILL PASS OVER THE AREA LATE TONIGHT AND WEDNESDAY MORNING AS FRONTAL BOUNDARY PUSHES OFF TO THE EAST AS A WARM FRONT. WEDNESDAY WILL BE THE MILDEST DAY OF THE WEEK...WITH HIGHS MOSTLY IN THE UPPER 50S AND LOWER 60S. WINDS WILL BE VARIABLE AS A WEAK SURFACE LOW DEVELOPS AND MOVES OVER THE AREA. THE NEXT COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY NIGHT. UPPER LEVEL ENERGY ACCOMPANYING THE FRONT LOOKS TO BE RELATIVELY WEAK...BUT ISOLATED TO SCATTERED SHOWERS ARE EXPECTED OVERNIGHT...MOSTLY IN THE FORM OF RAIN...AS COLDER AIR IS SLOW TO PUSH IN BEHIND THE FRONT. LOWS WILL MOSTLY BE IN THE 30S. THURSDAY LOOKS TO BE MAINLY CLOUDY AND COOL...WITH TEMPS NOT RISING MUCH. WILL GO WITH HIGHS IN THE MID 30S TO MID 40S FOR NOW. WEAK SHORTWAVE ENERGY PASSING ACROSS THE AREA WILL BRING A CONTINUED CHANCE FOR MOSTLY LIGHT RAIN AND SNOW SHOWERS. A STRONGER WAVE IS PROGGED TO PASS OVER THE AREA THURSDAY NIGHT INTO FRIDAY. THIS ONE HAS THE POTENTIAL TO BRING AT LEAST A LIGHT ACCUMULATION OF SNOW TO A GOOD PORTION OF THE AREA. VARIOUS MEDIUM RANGE MODELS STILL DIFFER ON TIMING AND TRACK OF WAVE...AND WHERE BETTER SNOW POTENTIAL WILL BE...SO WILL GO WITH CHANCE POPS FOR NOW ACROSS MUCH OF THE CWA. EXTENDED...THE MEDIUM RANGE MODELS CONTINUE TO SHOW A MAJOR CHANGE TO COLD UNSETTLED WEATHER FROM THE END OF THE WEEK THROUGH THE WEEKEND. A BROAD TROUGH DEVELOPING OVER THE NORTH CENTRAL U.S. WILL OPEN THE WAY FOR ARCTIC AIR TO POUR INTO THE NORTHERN PLAINS. THE JET STREAM WILL ALSO DROP INTO THE CENTRAL PLAINS ALLOWING ANOTHER COLD FRONT TO CROSS THE REGION ON FRIDAY...AND CARRY ADDITIONAL UPPER LEVEL SYSTEMS THROUGH THE DAKOTAS SATURDAY AND SUNDAY. A BRIEF WARMING TREND IS EXPECTED FOR THE FIRST COUPLE OF DAYS NEXT WEEK AFTER THE COLD AIRMASS MOVES EAST. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...WFO UNR/LBF LONG TERM....WFO UNR/LBF AVIATION...JACOBS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
ISSUED BY THE NATIONAL WEATHER SERVICE NORTH PLATTE NE 1010 AM CST TUE DEC 4 2012 .UPDATE...MADE SOME MINOR CHANGES TO THE ONGOING FCST...MAINLY TO DELAY THE ONSET OF CLOUDINESS THIS AFTERNOON BASED ON UPSTREAM SATELLITE IMAGERY. BASED ON THE 12Z UNR RAOB AND MIXED H85 TEMPS...HIGHS THIS AFTERNOON SHOULD BE AROUND 50 FOR RAPID CITY. H85 TEMPS IN THE LATEST RUC AND NAM SOLNS INCREASE AROUND A DEGREE OR TWO THIS AFTERNOON...SO HIGHS IN THE LOWER 50S SEEM PLAUSIBLE FOR RAPID CITY. WITH HIGH CLOUDINESS HOLDING OFF UNTIL THE MID AFTERNOON HOURS...ITS EFFECTS ON HIGHS ARE EXPECTED TO BE NEGLIGIBLE SO MIXED TEMPS WILL BE UTILIZED IN THE FCST. WINDS THIS AFTERNOON WILL SHIFT TO THE SOUTH AS HIGH PRESSURE BUILDS INTO EASTERN NORTH DAKOTA AND NORTHWESTERN MN. .AVIATION UPDATE...FOR THE 18Z TAFS...VFR FLT CONDS ARE EXPECTED OVER THE NEXT 24 HRS. && .PREV DISCUSSION... /ISSUED 316 AM MST MON DEC 3 2012/ DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS HIGH PRESSURE OVER THE CENTRAL ROCKIES. LOW PRESSURE IS OVER SOUTHWESTERN ONTARIO...WITH A COLD FRONT STRETCHING ACROSS NORTHERN MN...ND...AND NORTHEASTERN MT. UPPER LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE NORTHERN ROCKIES...WITH LOW REMAINING OFF THE PACIFIC NW COAST. SKIES ARE MOSTLY CLEAR ACROSS THE AREA WITH TEMPS IN THE MID 20S TO MID 30S. WINDS ARE LIGHT FROM THE WEST TO SOUTHWEST. MILD AND DRY CONDITIONS WILL CONTINUE THROUGH WEDNESDAY...WITH HIGHS 20 TO 25 DEGREES ABOVE AVERAGE ON WEDNESDAY. A COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY NIGHT...BRINGING TEMPS BACK TO MORE NORMAL LEVELS FOR THE END OF THE WEEK. A BROAD UPPER TROF WILL THEN SLOWLY SETTLE OVER THE AREA LATE IN THE WEEK..,BRINGING UNSETTLED WEATHER THROUGH THE WEEKEND AND KEEPING TEMPS ON THE COLD SIDE. FOR TODAY...SKIES WILL START OFF MAINLY SUNNY...WITH INCREASING MID AND HIGH CLOUDINESS FROM WEST TO EAST DURING THE DAY. THE WEAK COLD FRONT TO THE NORTH WILL SINK SLOWLY SOUTH AND WEST DURING THE DAY...STALLING OUT ALONG OR JUST EAST OF THE BLACK HILLS BY LATE TODAY. HIGHS WILL RANGE FROM THE MID 40S OVER THE HIGHER BLACK HILLS AND THE LEMMON AREA...TO THE MID 50S OVER MUCH OF SOUTHWESTERN AND SOUTH CENTRAL SD. SOUTHWESTERLY WINDS WILL INCREASE ACROSS NORTHEASTERN WY AND PORTIONS OF THE BLACK HILLS...BECOMING BREEZY AT TIMES ACROSS CAMPBELL CO...ESPECIALLY SOUTHERN CAMPBELL CO. EAST OF THE BLACK HILLS...WINDS WILL SWITCH OVER TO THE SOUTHEAST DURING THE AFTERNOON. SKIES WILL BE PARTLY CLOUDY IN GENERAL TONIGHT WITH LOWS MOSTLY IN THE 30S. WINDS WILL REMAIN BREEZY AT TIMES ACROSS PORTIONS OF NORTHEASTERN WY AND THE BLACK HILLS. WEAK RIDGE TO THE WEST WILL PASS OVER THE AREA LATE TONIGHT AND WEDNESDAY MORNING AS FRONTAL BOUNDARY PUSHES OFF TO THE EAST AS A WARM FRONT. WEDNESDAY WILL BE THE MILDEST DAY OF THE WEEK...WITH HIGHS MOSTLY IN THE UPPER 50S AND LOWER 60S. WINDS WILL BE VARIABLE AS A WEAK SURFACE LOW DEVELOPS AND MOVES OVER THE AREA. THE NEXT COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY NIGHT. UPPER LEVEL ENERGY ACCOMPANYING THE FRONT LOOKS TO BE RELATIVELY WEAK...BUT ISOLATED TO SCATTERED SHOWERS ARE EXPECTED OVERNIGHT...MOSTLY IN THE FORM OF RAIN...AS COLDER AIR IS SLOW TO PUSH IN BEHIND THE FRONT. LOWS WILL MOSTLY BE IN THE 30S. THURSDAY LOOKS TO BE MAINLY CLOUDY AND COOL...WITH TEMPS NOT RISING MUCH. WILL GO WITH HIGHS IN THE MID 30S TO MID 40S FOR NOW. WEAK SHORTWAVE ENERGY PASSING ACROSS THE AREA WILL BRING A CONTINUED CHANCE FOR MOSTLY LIGHT RAIN AND SNOW SHOWERS. A STRONGER WAVE IS PROGGED TO PASS OVER THE AREA THURSDAY NIGHT INTO FRIDAY. THIS ONE HAS THE POTENTIAL TO BRING AT LEAST A LIGHT ACCUMULATION OF SNOW TO A GOOD PORTION OF THE AREA. VARIOUS MEDIUM RANGE MODELS STILL DIFFER ON TIMING AND TRACK OF WAVE...AND WHERE BETTER SNOW POTENTIAL WILL BE...SO WILL GO WITH CHANCE POPS FOR NOW ACROSS MUCH OF THE CWA. EXTENDED...THE MEDIUM RANGE MODELS CONTINUE TO SHOW A MAJOR CHANGE TO COLD UNSETTLED WEATHER FROM THE END OF THE WEEK THROUGH THE WEEKEND. A BROAD TROUGH DEVELOPING OVER THE NORTH CENTRAL U.S. WILL OPEN THE WAY FOR ARCTIC AIR TO POUR INTO THE NORTHERN PLAINS. THE JET STREAM WILL ALSO DROP INTO THE CENTRAL PLAINS ALLOWING ANOTHER COLD FRONT TO CROSS THE REGION ON FRIDAY...AND CARRY ADDITIONAL UPPER LEVEL SYSTEMS THROUGH THE DAKOTAS SATURDAY AND SUNDAY. A BRIEF WARMING TREND IS EXPECTED FOR THE FIRST COUPLE OF DAYS NEXT WEEK AFTER THE COLD AIRMASS MOVES EAST. && .AVIATION...12Z TAFS VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...26 LONG TERM....CARPENTER AVIATION...CARPENTER UPDATE...NWS LBF
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1037 AM PST Tue Dec 4 2012 .SYNOPSIS... A strong and moist storm system will deliver widespread valley rain and mountain snow to all areas today. The snow could be locally heavy near the north Cascades and over the highest mountains elsewhere. The remainder of the week will be cooler and showery...with a series of weak weather disturbances moving through the Inland Northwest. && .DISCUSSION... A tricky update tot he forecast this morning as precipitation looks to redevelop over the southeastern portion of the region, but dry over the extreme northwest portion of the region. The tricky part is forecasting where this line of wet versus dry will actually set up. The HRRR model is doing the best with where we are currently seeing precipitation this morning. This guidance is suggesting that precipitation will become more widespread after noon today. Precipitation looks to remain east of a line from Moses Lake to Omak and up along the Cascade crest. Best chances will be across extreme eastern Washington and into the Idaho Panhandle. This precipitation will continue through tonight and taper off by Wednesday morning. Snow levels are expect to rise up around 5500 feet around Stevens Pass to around 4000 feet near the Canadian border this afternoon. This will result in rain for Stevens Pass. Loup Loup Pass may see a mix of some light rain and snow, but Blewett Pass will remain dry or see some light rainfall this afternoon as well. Web cams show all these passes transitioning from being snow covered to just wet pavement. Seeing that we will continue with strong westerly flow and much of the moisture remaining south of the area, we will go ahead and cancel the Winter Weather Advisory for the Cascades with this forecast update. /SVH && .AVIATION... 18Z TAFS: Rain and mountain snow across the region has tapered off a bit this morning as drier air aloft moved across the region. However, another slug of moisture is beginning to ride up into the region from the southwest. This will result in precipitaiton becoming more widespread this afternoon into tonight. Rainfall is expected at KGEG, KSFF, KCOE, KPUW and KLWS through early Wednesday morning; KMWH will be on the western fringe of this moisture. Low level moisture will keep cigs down through tonight with IFR/MVFR conditions expected to continue at most terminals. Winds are expected to become a little breezy overnight as low levels become a bit more unstable. This should begin to break up the stratus Wednesday morning as drier air aloft is mixed down toward the surface. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 45 39 41 28 35 26 / 60 80 10 10 60 70 Coeur d`Alene 45 39 40 28 35 25 / 70 90 40 10 70 80 Pullman 46 40 42 29 37 28 / 90 90 40 10 50 60 Lewiston 52 45 48 33 45 31 / 60 90 30 10 30 60 Colville 44 41 41 30 36 25 / 30 80 20 30 70 70 Sandpoint 42 39 39 28 34 25 / 70 90 50 30 80 90 Kellogg 42 37 37 30 33 25 / 100 100 50 20 80 90 Moses Lake 49 40 45 26 37 25 / 20 20 0 10 10 20 Wenatchee 45 37 44 27 38 26 / 20 20 0 10 40 20 Omak 43 36 40 25 35 21 / 20 20 10 10 40 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$