Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/11/12
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1035 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 1000 PM MST SAT DEC 8 2012
AT 10 PM DROPPED THE WARNINGS FOR ZONE 4 AND 13, THE ADVISORY FOR
ZONE 5 AND ADDED A LOW END ADVISORY FOR ZONE 8 WHERE THE ROADS
THROUGH GLENWOOD CANYON TO AVON APPEAR TO BE A MESS.
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ004-008-009-
013-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ010.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1004 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 1000 PM MST SAT DEC 8 2012
AT 10 PM DROPPED THE WARNINGS FOR ZONE 4 AND 13, THE ADVISORY FOR
ZONE 5 AND ADDED A LOW END ADVISORY FOR ZONE 8 WHERE THE ROADS
THROUGH GLENWOOD CANYON TO AVON APPEAR TO BE A MESS.
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
STILL CONTEMPLATING HOW TO HANDLE THE STRONG-LEANING HIGHLIGHTS
THAT ARE CURRENTLY IN EFFECT. COORDINATED WITH CYS TO LOWER THE
WARNING OVER ZONE 4. ZONE 5 STEAMBOAT ALSO SEEMS TO BE DONE WITH
SIGNIFICANT SNOW ACCUMULATION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ004-008-009-
013-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ010.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
921 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 920 PM MST SAT DEC 8 2012
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
STILL CONTEMPLATING HOW TO HANDLE THE STRONG-LEANING HIGHLIGHTS
THAT ARE CURRENTLY IN EFFECT. COORDINATED WITH CYS TO LOWER THE
WARNING OVER ZONE 4. ZONE 5 STEAMBOAT ALSO SEEMS TO BE DONE WITH
SIGNIFICANT SNOW ACCUMULATION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ009-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ004-010-013.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ005.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS ALBANY NY
955 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL TRACK THROUGH THE REGION TONIGHT. COLDER
WEATHER WILL ARRIVE ON GUSTY NORTHWEST WINDS OVERNIGHT...CHANGING
RAIN SHOWERS TO SNOW SHOWERS OVER THE HIGHER TERRAIN. TUESDAY
LOOKS PARTLY SUNNY WITH A CHILLY NORTHWEST WIND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 945 PM EST...PRECIPITATION HAS CHANGED TO SNOW ACROSS HIGHER
ELEVATIONS OF THE WESTERN ADIRONDACKS...WHERE SOME BURSTS OF
MODERATE TO LOCALLY HEAVY SNOW HAVE OCCURRED. THIS REGION APPEARS
TO BE WITHIN AN AREA OF STRONG 850-700 MB FGEN...WHICH IS WORKING IN
COMBINATION WITH MOISTURE/UPSLOPE FROM BRISK W/NW WINDS OFF THE
LAKES TO HELP ENHANCE THE SNOWFALL. HAVE BOOSTED SNOWFALL TOTALS A
BIT IN THIS REGION...FROM NORTHERN HERKIMER INTO NORTHERN HAMILTON
COS...INTO THE 1-3 INCH RANGE.
ELSEWHERE...THE COLD FRONT IS NOW LOCATED FROM THE SOUTHERN
BERKSHIRES...INTO NORTHERN DUTCHESS/ULSTER COS...AND CONTINUING TO
DROP SOUTH/SOUTHEAST. LITTLE IN THE WAY OF RAINFALL HAS BEEN
OCCURRING AHEAD OF THE FRONT...WITH ONLY SOME LIGHT SHOWERS
ACCOMPANYING THE FRONTAL PASSAGE. HOWEVER...THE LATEST HRRR AND
RUC13 INDICATE A POSSIBLE UPPER LEVEL IMPULSE RIDING NE ACROSS
CENTRAL OR SOUTHERN PORTIONS OF THE REGION JUST AFTER
MIDNIGHT...WITH AN AREA OF ENHANCED MID LEVEL F-GEN SLIDING
ACROSS SOUTHERN/CENTRAL AREAS. WILL THEREFORE BOOST POPS UPWARD A BIT
AFTER MIDNIGHT IN THESE AREAS FOR RAIN SHOWERS...ALTHOUGH HIGHER
ELEVATIONS ACROSS THE TACONICS...CATSKILLS AND BERKSHIRES WILL
LIKELY CHANGE TO SNOW BEFORE ENDING. THIS COULD LEAVE A COATING TO
LESS THAN AN INCH OF ACCUM. FURTHER N AND W...LIGHT RAIN SHOWERS
SHOULD TRANSITION TO SNOW SHOWERS AFTER MIDNIGHT...AND COULD LEAVE
A COATING IN SOME AREAS...ESP ACROSS HIGHER ELEVATIONS...WHERE
PERHAPS UP TO AN INCH COULD OCCUR ACROSS PORTIONS OF THE
HELDERBERGS/CATSKILLS AND SCHOHARIE VALLEY REGION. ALSO...A
COATING TO ONE INCH WILL BE POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN GREEN MOUNTAINS AND NORTHERN BERKSHIRES.
ALTHOUGH LOW LEVEL COLD ADVECTION WAS INITIALLY FAIRLY MODEST...IT
APPEARS TO BE LEVELING OFF A BIT. ANOTHER...SECONDARY BOUNDARY WAS
NOTED NORTH OF LAKE ONTARIO...WITH MUCH COLDER AIR BEHIND IT.
HOWEVER...THIS MAY NOT REACH NORTHERN AREAS UNTIL WELL AFTER
MIDNIGHT...AND PERHAPS NOT UNTIL DAYBREAK OR EVEN THEREAFTER
FURTHER SOUTH AND EAST. HAVE THEREFORE BOOSTED OVERNIGHT MINS BY
ABOUT 3 DEGREES IN MOST AREAS...WITH MINS EXPECTED TO FALL INTO
THE LOWER/MID 20S ACROSS THE SOUTHERN ADIRONDACKS...UPPER 20S TO
LOWER 30S ACROSS HIGHER TERRAIN OF WESTERN NEW ENGLAND...TO
LOWER/MID 30S IN VALLEY REGIONS FROM ALBANY N AND W...AND
GENERALLY 35-40 TO THE S AND E.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
BASED ON THE COOLING OF BOUNDARY LAYER TEMPERATURES...AND THE WEST
TO WEST NORTHWEST LOW LEVEL WIND FLOW...THERE COULD BE SOME LAKE
EFFECT CLOUD COVER AND SCATTERED SNOW SHOWER ACTIVITY...
ESPECIALLY IN THE WESTERN MOHAWK VALLEY...SOUTHERN ADIRONDACKS AND
SCHOHARIE VALLEY. ALTHOUGH DRIER AIR WILL FILTER INTO THE
REGION...DECREASING THE MID LEVEL CLOUDS...SOME LAKE EFFECT CLOUDS
MAY BE TOUGH TO BREAK UP ACROSS PORTIONS OF THE MOHAWK VALLEY
REGION...CAPITAL REGION AND BERKSHIRES. HAVE THEREFORE BOOSTED
CLOUD COVERAGE UPWARD A BIT IN THESE AREAS THROUGH AT LEAST EARLY
AFTERNOON. HIGHS IN THE UPPER 30S TO MID 40S...20S IN HIGHER
ELEVATIONS.
HIGH PRESSURE BUILDS OVER THE REGION...BUT THERE ARE HINTS OF
SOME WEAK WARM ADVECTION AHEAD OF A REINFORCING SHOT OF COOLER AIR
LATE AT NIGHT...ALONG WITH AN INCREASE IN BOUNDARY LAYER WINDS IN
NORTHERN AREAS...THAT COULD PREVENT TEMPERATURES FROM DROPPING AS
COLD AS THEY COULD BE. LOWS TOMORROW NIGHT IN THE LOWER TO MID
20S...TEENS IN THE HIGHER ELEVATIONS.
HIGH PRESSURE CONTINUES TO CONTROL THE AREA ACROSS THE REGION
THROUGH THURSDAY...BUT A WEAK REINFORCING SHOT OF COOLER AIR
TRACKS INTO THE REGION LATE WEDNESDAY AND WEDNESDAY NIGHT...BUT
VERY WEAK. WEAK WARM ADVECTION AHEAD OF THE WEAK COLD FRONT COULD
SKEW THE LOW LEVEL WINDS TO THE WEST WEDNESDAY AFTERNOON...WHICH
COULD NUDGE TEMPERATURES UP A DEGREE OR TWO...BUT WINDS SHOULD
GENERALLY BE LIGHT AND MIXING LIMITED WITH THE SHORT DAYLIGHT
HOURS...PLUS AFTER RELATIVELY COLD MORNING LOWS...IT WILL TAKE SOME
DECENT MIXING TO WARM TO GUIDANCE LEVELS. BOUNDARY LAYER WINDS
COULD BE STRONGER IN NORTHERN AREAS WHERE MIXING COULD BE
BETTER....WHICH COULD ALSO NUDGE TEMPERATURES UP A DEGREE OR TWO
IN NORTHERN AREAS. HIGHS WEDNESDAY IN THE UPPER 30S TO LOWER
40S...LOWER TO MID 30S HIGHER ELEVATIONS.
LOWS WEDNESDAY NIGHT IN THE LOWER TO MID 20S...WITH SLOWLY
STRENGTHENING WARM ADVECTION...AND PERHAPS SOME THIN HIGH CLOUDS
BEGINNING TO SPREAD ACROSS THE REGION. HIGHS THURSDAY IN THE LOWER
TO MID 40S...SOME MID TO UPPER 30S IN HIGHER ELEVATIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERALLY POPULATED THIS PORTION OF THE EXTENDED GRIDDED DATABASE
WITH 18Z/10 HPC GUIDANCE...FAVORING CLOSER TO THE 12Z/10 ECMWF.
THU NT-SAT...GENERALLY FAIR CONDITIONS EXPECTED DURING THIS
PERIOD...WITH TEMPS NEAR OR A SHADE ABOVE SEASONAL LEVELS. EXPECT
MAX TEMPS MAINLY TO REACH 35-40 IN MOST AREAS...MAYBE A BIT HIGHER
ACROSS THE MID HUDSON VALLEY...AND OVERNIGHT MINS MAINLY IN THE
20S...WITH SOME TEENS POSSIBLE ACROSS TRADITIONALLY COLDER REGIONS
ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN NEW ENGLAND.
SAT NT-MON...SIGNIFICANT DISPARITY AMONG DETERMINISTIC MODELS DURING
THIS PERIOD...ALTHOUGH ALL SUGGEST A DEVELOPING BLOCKY PATTERN
ACROSS NORTH AMERICA EXTENDING INTO THE NORTH ATLANTIC OCEAN.
HOWEVER...EXACTLY WHERE SPECIFIC ELEMENTS OCCUR WITHIN THIS EVOLVING
PATTERN STILL SOMEWHAT TOUGH TO DISCERN...WITH THE 12Z/10 GFS MORE
PROGRESSIVE...AND SLIGHTLY FURTHER SOUTH WITH CLOSED LOWS AND LESS
AMPLIFIED OVERALL...WHILE THE 12Z/10 ECMWF IS MORE AMPLIFIED WITH
STRONGER CLOSED LOWS DEVELOPING WITHIN THE MID LATITUDES. HAVE
GENERALLY LEANED A BIT CLOSER TO THE 12Z/ECMWF SOLUTION...WITH THE
IDEA OF A STORM SYSTEM APPROACHING FROM THE SOUTHWEST FOR
SUNDAY...AND SLOWLY DEPARTING FOR MONDAY. ALTHOUGH A PERIOD OF
RAIN/SNOW IS INDICATED IN THE GRIDS...WITH P-TYPE MAINLY DETERMINED
BY DIURNAL TEMPERATURE VARIATIONS...IT IS ENTIRELY POSSIBLE THAT
SOME MIXED PRECIPITATION COULD ULTIMATELY OCCUR ACROSS AT LEAST
NORTHERN AREAS...AND PERHAPS HIGHER ELEVATIONS FURTHER SOUTH. SHOULD
A SYSTEM AS STRONG AS THE 12Z/10 ECMWF OCCUR...SIGNIFICANT AMOUNTS
OF PRECIPITATION COULD AFFECT THE REGION. BUT AGAIN...TONS OF
UNCERTAINTY STILL EXISTS AT THIS TIME RANGE...SO NO SPECIFICS JUST
YET AS THERE REMAINS ROOM FOR MODEL SOLUTIONS TO CHANGE
SIGNIFICANTLY. UTILIZING HPC MOS FOR TEMPS...EXPECT MAXES TO
GENERALLY REACH THE MID 30S TO LOWER 40S...WARMEST IN VALLEYS...WITH
OVERNIGHT MINS MAINLY IN THE 30S...ALTHOUGH SOME 20S COULD BE
POSSIBLE...ESP SHOULD ANY POTENTIAL STORM SYSTEM TRACK FURTHER SOUTH
AND EAST.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT WILL MOVE FROM NORTHWEST TO SOUTHEAST ACROSS THE TAF
SITES EARLY THIS EVENING. RAIN SHOWERS WILL ACCOMPANY AND
IMMEDIATELY FOLLOW THIS FRONTAL PASSAGE. DRIER WEATHER WILL FILTER
INTO THE REGION FROM THE NORTHWEST ON TUESDAY.
AREAS OF IFR/LIFR CIGS SHOULD BECOME MVFR/VFR OVER THE NEXT 1-2
HOURS AT KGFL AND KALB AS THE FRONT MOVES THROUGH. AT
KPOU...MAINLY MVFR CONDITIONS ARE EXPECTED UNTIL THE FRONT
PASSES. CONDITIONS WILL BE MAINLY MVFR TO VFR IN THE WAKE OF THE
FRONT...DESPITE OCCASIONAL LIGHT RAIN SHOWERS. SOME WET SNOW/SNOW
GRAINS COULD MIX IN WITH THE RAIN AFTER MIDNIGHT BEFORE THE
SHOWERS END.
AS WINDS SHIFT INTO THE WEST/NORTHWEST...SOME IFR CIGS MAY DEVELOP
AT KPSF IMMEDIATELY BEHIND THE FRONT. THESE CIGS SHOULD GRADUALLY
LIFT AFTER MIDNIGHT INTO MVFR TO VFR.
VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF TUESDAY.
OUTLOOK...
TUE NIGHT-SAT...VFR. NO SIG. WX.
&&
.HYDROLOGY...
RAINFALL TOTALS SO FAR HAVE BEEN HEAVIEST OVER THE UPPER MOHAWK
VALLEY AND THE SOUTHWESTERN ADIRONDACKS WHERE THREE QUARTERS OF AN
INCH TO AN INCH AND A QUARTER OF RAIN HAS BEEN REPORTED.
ELSEWHERE...A HALF AN INCH OR LESS HAS BEEN REPORTED. ADDITIONAL
RAINFALL LOOKS TO BE LESS THAN AN INCH...ALTHOUGH A FEW LOCALLY
HEAVY DOWNPOURS ARE POSSIBLE THIS EVENING IN THE EASTERN
CATSKILLS...BERKSHIRES AND LITCHFIELD HILLS JUST AHEAD OF THE
COLD FRONT.
THIS RAIN WILL RESULT IN HALF TO THREE QUARTER BANKFULL RISES OVER
NORTHWESTERN AREAS AND UP TO HALF BANKFULL OVER SOUTHEASTERN AREAS.
AT THIS TIME...NO RIVER FLOODING IS EXPECTED.
AFTER TONIGHT...DRY WEATHER IS EXPECTED THROUGH FRIDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...KL/NAS
SHORT TERM...KL/NAS
LONG TERM...KL
AVIATION...KL/IRL/SND
HYDROLOGY...SND/NAS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
648 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT CRESTING THE APPALACHIANS WILL CROSS THE REGION TONIGHT.
AN AREA OF LOW PRESSURE TRACKING ALONG THE FRONT IS EXPECTED TO
SLIDE WELL SOUTHEAST OF OUR AREA ON WEDNESDAY, AS HIGH PRESSURE
BUILDS IN FROM THE WEST. THIS HIGH WILL REMAIN OVER OUR AREA INTO
FRIDAY BEFORE MOVING OFFSHORE. A WEAK COLD FRONT IS THEN FORECAST
TO DROP SOUTH INTO THE AREA FRIDAY NIGHT. A STRONG LOW PRESSURE
SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES
REGION THIS WEEKEND. ITS COLD FRONT SHOULD MOVE THROUGH THE AREA
LATER ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE OVER SERN CANADA WILL CONTINUE TO MOVE NEWD. THE COLD
FRONT ATTACHED TO THE LOW IS ACROSS WRN/CENTRAL PA ATTM AND WILL
MOVE SLOWLY EAST AND CROSS OUR AREA WITHIN A FEW HOURS OF
MIDNIGHT. AREAS OF LOW CLOUDS AND FOG CONTINUE ACROSS THE AREAS
NORTH OF THE WARM FRONT. SOME BREAKS IN THE CLOUDS AND A FEW
SHOWERS ARE ACROSS THE DELMARVA AND SRN NJ BEHIND THE FRONT. WE
WILL KEEP LIKELY/CATEGORICAL POPS FOR TONIGHT WITH THE VARIOUS
FEATURES MOVING THROUGH. SHOWERY WEATHER WITH ONLY A VERY SMALL
POSSIBILITY FOR SOME THUNDER (NOT INCLUDED IN THE GRIDS). OVERALL
QPF FOR THE SYSTEM WILL RANGE FROM .10 TO .25 IN MOST AREAS.
COOLER AND DRIER AIR WILL ARRIVE BY DAWN WITH THE LOWS OCCURRING
THEN. WINDS MAY BECOME GUSTY UP TO 20 MPH BY DAWN. LOWS WILL BE IN
THE MID TO UPPER 30S ACROSS THE NORTH AND LOW TO MID 40S OVER
OTHER AREAS.
FOR THE LATEST UPDATE, HAVE TWEAKED POPS A BIT, BUT CONFIDENCE IS
QUITE LOW ON HOW THINGS WILL PLAY OUT OVER THE NEXT FEW HOURS.
LATEST RADAR IMAGERY SHOWED AN AREA OF SHOWERS OVER SRN NJ AND
SOME LIGHT SHOWERS APPROACHING THE WRN PORTIONS OF OUR CWA. THE
REST OF THE AREA IS DRY. SO THE HIGH POPS WE ARE CURRENTLY
CARRYING SEE A BIT HIGH. HOWEVER, UNTIL THE FRONT COMES THRU,
DON`T WANT TO GO TOO LOW. LATEST GUID IS ALL OVER THE PLACE AS
WELL, WITH GFS AND HRRR BASICALLY DRY AND NAM/WRF WETTER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE COLDER AND DRIER AIR WILL CONTINUE TO SWEEP ACROSS THE AREA
TUESDAY. HIGH PRESSURE FROM THE OHIO VALLEY AND GREAT LAKES WILL
BUILD ACROSS THE AREA. SKY COVER ON TUESDAY WILL BE PARTLY TO MOSTLY
SUNNY...WITH A FEW LINGERING CLOUDS SOUTH/EAST EARLY. NO
PRECIPITATION IS EXPECTED TUESDAY. HIGH TEMPERATURES WILL BE IN THE
LOW TO MID 40S UP NORTH...AND AROUND 50 DECREES ACROSS THE CENTRAL
AND SRN PARTS OF THE REGION. WINDS WILL BE NORTHWEST AT 10 TO 15
MPH...WITH SOME GUSTS AROUND 20 MPH...ESPECIALLY DURING THE MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE LONG TERM REMAINS RELATIVELY QUIET INTO THE START OF THE WEEKEND
WITH UNSETTLED WEATHER FOR THE END OF THE WEEKEND INTO MONDAY.
THERE ARE NO APPRECIABLE CHANGES EXPECTED WITH THE TELECONNECTION
INDICES WHICH CONTINUE TO OVERALL FAVOR A PROGRESSIVE ALTHOUGH
MORE ACTIVE PATTERN AND (NOW THAT TODAY IS OUT OF THE WAY) NEAR TO
MODERATELY ABOVE NORMAL TEMPERATURES. THE GFS INITIALIZATION
REMAINS SLIGHTLY BETTER THAN THE WRF-NMMB. AT THE START OF THE
LONG TERM, BOTH MODELS ARE NOW MUCH CLOSER. TOWARD THE END OF THE
LONG TERM, THE ECMWF AND GFS ARE IN THEIR PERSPECTIVE BIAS CAMPS
WHICH FOR US WILL FOLLOW A COMPROMISE SOLUTION. WHILE THE GFS
SOLUTION HAS BEEN VERY NOISY, WITH THE FORECAST FORMATION OF A
50/50 LOW, THE IDEA OF TRIPLE POINT REDEVELOPMENT OR LESS OF AN UP
THE SAINT LAWRENCE VALLEY TRACK APPEARS THE MORE LIKELY EVOLUTION
AT THIS POINT.
NOW THAT THE SHORT WAVE IN QUESTION ASSOCIATED WITH WAVE "NUMBER
THREE" IS MORE DENSELY SAMPLED, MODELING SOLUTION HAS CLUSTERED
TOWARD A NON (PREVIOUS RUNS OF IT) WRF-NMMB SOLUTION. A SLIGHTLY
SLOWER AND MORE SHEARED TROF IS THE CONSENSUS. OUR PROBLEM FOR
TUESDAY NIGHT IS THE PRESENCE OF THE JET ALOFT. WE SHOULD GET SOME
CIRRUS FROM THE DEVELOPMENT OF THIS WAVE AND AS SUCH CONFIDENCE
ABOUT MINIMUM TEMPERATURES IS ONLY MODERATE.
THE SAME CAN BE SAID FOR WEDNESDAY DAY AS THE JET IS STILL FORECAST
TO BE OVER OUR AREA AND A SHORT WAVE IN THE SOUTHWEST FLOW
APPROACHING. THUS WE ARE EXPECTING NO SHORTAGE OF MID AND ESPECIALLY
HIGH LEVEL CLOUDS. WITH CONSENSUS, WE KEPT LOW LOW PCPN CHCS OFSHR
AND SHAVED OFF THE NORTHERN WATER POPS. MAX TEMPS WERE FAIRLY
SUBDUED VS STAT GUIDANCE BECAUSE OF THE EXPECTED CLOUDS.
THE TROF IS EXPECTED TO CLEAR OUR CWA ON WEDNESDAY NIGHT, SO AWAY
FROM THE COAST AND URBAN CENTERS, WE WENT BELOW STAT GUIDANCE.
RADIATIONAL COOLING CONDITIONS LOOK PRETTY GOOD. SECOND THURSDAY
IN A ROW WITH A LARGE HIGH PRESSURE SYSTEM CRESTING OVER OUR CWA
WITH RELATIVELY LIGHT WINDS FORECAST. NO APPRECIABLE CHANGES WERE
MADE TO THE MAX TEMPS.
ON FRIDAY A WEAK BACKDOOR COLD FRONT IS FORECAST TO APPROACH AND
THEN PASS THROUGH OUR CWA THAT NIGHT, NOT MUCH MOISTURE IS
FORECAST TO BE AVAILABLE TO GENERATE PCPN. ON THE WEEKEND WE
START CLOSE TO THE ECMWF SOLUTION AND THEN SEGUE CLOSER TO A GFS
AND ECMWF TIMING COMPROMISE BY MONDAY. LOW POPS WERE KEPT ON
SATURDAY AFTERNOON NORTHWEST AND THEN SPREAD ACROSS OUR CWA
SATURDAY NIGHT. MONDAY WILL BE STARTED AS A DRY FORECAST. AS
MENTIONED EARLIER, WITH AT LEAST A BRIEF 50/50 LOW A WEST TO EAST
TRACK SOLUTION IS FAVORED. THIS CONTINUES THE CHANCES FOR A WINTRY
MIX OF PRECIPITATION AT THE START AND END OF THIS UPCOMING
PRECIPITATION EVENT IN THE NORTHERN PART OF OUR CWA.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
LOW CONFIDENCE FCST FOR THE NEXT FEW HOURS. WHILE KRDG AND KABE
AND KACY REMAINED SOCKED IN WITH IFR AND LIFR. MOST OTHER AREAS
HAVE IMPROVED AND ARE VFR. SO THE LOW CLOUDS ARE AROUND AND ALL OF
THE AVAILABLE GUID SAYS CONDS WILL COME DOWN AT THOSE TAF SITES
WHERE THERE ARE CURRENTLY VFR CONDS. HOWEVER, NONE OF THE GUID HAD
THE VFR EITHER. SO, NOT SURE HOW LONG ITS GOING TO LAST.
THE POTENTIAL FOR POOR CONDS WILL LAST UNTIL A CDFNT CROSSES THE
REGION OVERNIGHT. SHOWERS MAY ACCOMPANY THE FRONT...BUT MAY STIR UP
THE ATMOSPHERE ENOUGH TO KEEP VSBYS ABOUT THE SAME (OR MAYBE EVEN
INCREASE) AS THEY GO THROUGH.
DRIER AIR BEHIND THE FRONT WILL BRING CIGS/VSBYS BACK TO VFR BEFORE
DAWN ACROSS THE REGION. NW WINDS WILL BE GUSTY TO AROUND 20 KTS
DURING THE MORNING ACROSS THE AREA. SKY COVER WILL CONTINUE TO
DECREASE TO FEW-SCT ACROSS THE AREA TUESDAY.
OUTLOOK...
TUESDAY NIGHT...VFR.
WEDNESDAY...VFR. SOME MODERATE NORTH WINDS AT ATLANTIC COASTAL
AIRPORTS.
THURSDAY THROUGH SATURDAY...VFR. CONFIDENCE HIGHEST THURSDAY AND
FRIDAY.
&&
.MARINE...
WE WILL KEEP THE SCA FLAG AS IS FOR NOW WITH SEAS MOSTLY 4 TO 6 FT
TONIGHT AND TUESDAY ON THE WATERS. SRLY OR SWRLY WINDS THIS EVENING
AHEAD OF THE FRONT AND NWRLY WINDS EXPECTED LATE TONIGHT AND TUESDAY
BEHIND THE FRONT. SOME WIND GUSTS MAY APPROACH THE SCA CRITERIA OF
25 KTS...BUT OVERALL THE FLAG WILL BE FOR THE ENHANCED SEAS. WE WILL
NOT PUT UP ANY SCA FLAGS FOR DEL BAY ATTM. PATCHY FOG MAY BE AROUND
THE WATERS THIS EVENING...BUT SHOULD DIMINISH AS SHOWERS STIR UP THE
ATMOSPHERE OVERNIGHT. TUESDAY...FAIR WEATHER EXPECTED WITH SOME
GUSTY NW WINDS UP TO 20 KTS ON THE WATERS.
OUTLOOK...
WINDS AND SEAS ARE NOT OUTLOOKED TO REACH SMALL CRAFT ADVISORY
CRITERIA ON DELAWARE BAY INTO SATURDAY.
ON THE OCEAN HOWEVER, CONFIDENCE IS NOT AS HIGH. WE SHOULD START
TUESDAY NIGHT WITH WIND GUSTS CLOSE TO SCA CRITERIA, BUT TRENDING
DOWNWARD. THE MODELING CONSENSUS IS TOWARD LESS OF A FINAL WAVE ON
THE FRONT WEDNESDAY INTO THURSDAY. REGARDLESS THERE REMAINS A CHANCE
THAT WINDS MIGHT REACH SMALL CRAFT ADVISORY CRITERIA ON THE SOUTHERN
OCEAN WATERS ON WEDNESDAY NIGHT, WITH THE POSSIBILITY OF SWELLS OF
AROUND 5 FEET ON THE SOUTHERN OCEAN WATERS ON THURSDAY. FOR THE
REST OF THE OUTLOOK PERIOD, THE HIGH PRESSURE SYSTEM WILL BUILD
EASTWARD WITH LIGHTER WINDS EXPECTED THURSDAY NIGHT AND FRIDAY. BY
THEN THE WEAK WAVE SHOULD ALSO BE FARTHER OFFSHORE AND SO WILL
THE SWELLS. A WEAK FRONT PASSING THROUGH THE AREA WATERS FRIDAY
NIGHT IS NOT OUTLOOKED TO GENERATE MUCH ADDITIONAL WINDS OR SEAS.
THE RETURN SOUTHERLY TO SOUTHEASTERLY FLOW IS EXPECTED TO INCREASE
STARTING ON SATURDAY, BUT IS NOT GRIDDED TO REACH CRITERIA UNTIL
DURING SUNDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TUESDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...GIGI/GORSE
NEAR TERM...NIERENBERG/O`HARA
SHORT TERM...O`HARA
LONG TERM...GIGI/NIERENBERG
AVIATION...GIGI/GORSE/O`HARA
MARINE...GIGI/O`HARA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* PERIODIC MVFR CIGS LIKELY TO GENERALLY PERSIST OVERNIGHT
* SOME LIGHT SNOW/FLURRIES EXPECTED OVERNIGHT WITH MINIMAL VSBY
REDUCTIONS
* SOUTHWEST WINDS WILL GUST TO AROUND 20KT TUESDAY LATE MORNING
INTO THE AFTERNOON
IZZI
//DISCUSSION...UPDATED 03Z...
A HOLE IN THE OVC DEVELOPED OVER CHICAGO EARLY THIS EVENING BUT
FAIRLY SOLID STRATUS/STRATOCUMULUS DECK UPSTREAM EXPECTED TO
RESULT IN MVFR/LOW END VFR CIGS MOVING BACK IN. CLOUD TOPS HAVE
BEEN COOLING SOMEWHAT OVER NORTH CENTRAL ILLINOIS IN REGION OF
WEAK WARM AIR ADVECTION WITH GROWING AREA OF CLOUD TOPS TO -19C
CORRESPONDING NICELY WITH A BLOSSOMING AREA OF LIGHT
SNOW/FLURRIES. GIVEN RADAR AND SATELLITE TRENDS HAVE OPTED TO ADD
A TEMPO FOR FLURRIES TO THE TAFS OVERNIGHT...BUT GENERALLY
EXPECTING LITTLE IMPACT OF PREVAILING VSBY.
IZZI
UPDATED 00Z...
STATUS/STRATOCUMULUS DECK ON THE BACK SIDE OF THE DEPARTING STORM
SYSTEM WILL BLANKET THE AREA WITH GENERALLY MVFR CIGS MUCH OF THE
NIGHT. REGIONAL OBSERVATIONS INDICATE THAT THE CLOUD BASES ARE
RATHER RAGGED WITH CIGS RANGING FROM LOW END MVFR TO OCCASIONALLY
VFR. WOULD GENERALLY EXPECT MVFR CIGS AT THE TERMINALS TONIGHT
THOUGH SOME VARIABILITY IS LIKELY FROM TIME TO TIME AND OFTEN
TIMES JUST PRIOR TO CLEARING CIGS WILL HAVE A TENDENCY TO LOWER.
NONE OF THE POTENTIAL VARIABILITY IS INCLUDED IN THE TAFS SINCE IT
WOULD HAVE LITTLE TO NO IMPACT ON OPS AND PRECTIBILITY IS LOW.
LOW LEVEL FLOW WILL BACK TONIGHT TO SOUTHWEST AND THAT SHOULD HELP
CLEARING LINE NEAR THE MS RIVER MAKE STEADY NORTHEAST PROGRESS AND
CLEAR THE CLOUDINESS OUT...LIKELY PRIOR TO SUNRISE. SOUTHWEST
WINDS WILL INCREASE TUESDAY WITH GUSTS TO AROUND 20KT EXPECTED TO
DEVELOP BY MIDDAY AND CONTINUE INTO THE AFTERNOON BEFORE WANING
TOWARD EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN CIGS TONIGHT AND TIMING OF CLEARING
* MEDIUM CONFIDENCE IN -SN OVERNIGHT
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY THROUGH FRIDAY...VFR.
SATURDAY...RAIN LIKELY. IFR PROBABLE.
SUNDAY...MVFR CIGS LIKELY.
IZZI
&&
.MARINE...
313 PM CST
N AND NE WINDS WILL DIMINISH TONIGHT AS LOW PRESSURE IN SW QUEBEC
MOVES E TO THE GULF OF SAINT LAWRENCE OVERNIGHT ALLOWING HIGH
PRESSURE OVER ONTARIO TO DROP SSE TO THE LOWER GREAT LAKES. S AND
SW WINDS WILL BE ON THE INCREASE TUE AS THE HIGH MERGES WITH
ANOTHER HIGH PRESSURE RIDGE OVER THE SOUTHERN PLAINS...OZARKS AND
LOWER OH VALLEY. WINDS SLACKEN AGAIN OVERNIGHT TUE BEFORE
FRESHENING AGAIN DURING WED AS LOW PRESSURE IN THE NORTHERN HIGH
PLAINS ELONGATES ACROSS THE UPPER MIDWEST INTO ONTARIO BY THU.
WINDS MAY REACH GALE FORCE BY WED NIGHT ON NORTHERN LAKE MI...AND
PERSIST INTO THU. THE LOW PRESSURE TROUGH DROPS S ACROSS THE GREAT
LAKES FRI WHILE LOW PRESSURE DEEPENS AS IT MOVES E FROM THE
CENTRAL ROCKIES TO THE CENTRAL PLAINS FRI AND FRI NIGHT. THIS LOW
TURNS NE TO THE MID MS VALLEY SAT AND MOVES INTO THE UPPER GREAT
LAKES SAT NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
531 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR CIGS LIKELY TO GENERALLY PERSIST TONIGHT
* SOUTHWEST WINDS WILL GUST TO AROUND 20KT TUESDAY LATE MORNING
INTO THE AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
STATUS/STRATOCUMULUS DECK ON THE BACK SIDE OF THE DEPARTING STORM
SYSTEM WILL BLANKET THE AREA WITH GENERALLY MVFR CIGS MUCH OF THE
NIGHT. REGIONAL OBSERVATIONS INDICATE THAT THE CLOUD BASES ARE
RATHER RAGGED WITH CIGS RANGING FROM LOW END MVFR TO OCCASIONALLY
VFR. WOULD GENERALLY EXPECT MVFR CIGS AT THE TERMINALS TONIGHT
THOUGH SOME VARIABILITY IS LIKELY FROM TIME TO TIME AND OFTEN
TIMES JUST PRIOR TO CLEARING CIGS WILL HAVE A TENDENCY TO LOWER.
NONE OF THE POTENTIAL VARIABILITY IS INCLUDED IN THE TAFS SINCE IT
WOULD HAVE LITTLE TO NO IMPACT ON OPS AND PRECTIBILITY IS LOW.
LOW LEVEL FLOW WILL BACK TONIGHT TO SOUTHWEST AND THAT SHOULD HELP
CLEARING LINE NEAR THE MS RIVER MAKE STEADY NORTHEAST PROGRESS AND
CLEAR THE CLOUDINESS OUT...LIKELY PRIOR TO SUNRISE. SOUTHWEST
WINDS WILL INCREASE TUESDAY WITH GUSTS TO AROUND 20KT EXPECTED TO
DEVELOP BY MIDDAY AND CONTINUE INTO THE AFTERNOON BEFORE WANING
TOWARD EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE IN CIGS TONIGHT AND TIMING OF CLEARING
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY THROUGH FRIDAY...VFR.
SATURDAY...RAIN LIKELY. IFR PROBABLE.
SUNDAY...MVFR CIGS LIKELY.
IZZI
&&
.MARINE...
313 PM CST
N AND NE WINDS WILL DIMINISH TONIGHT AS LOW PRESSURE IN SW QUEBEC
MOVES E TO THE GULF OF SAINT LAWRENCE OVERNIGHT ALLOWING HIGH
PRESSURE OVER ONTARIO TO DROP SSE TO THE LOWER GREAT LAKES. S AND
SW WINDS WILL BE ON THE INCREASE TUE AS THE HIGH MERGES WITH
ANOTHER HIGH PRESSURE RIDGE OVER THE SOUTHERN PLAINS...OZARKS AND
LOWER OH VALLEY. WINDS SLACKEN AGAIN OVERNIGHT TUE BEFORE
FRESHENING AGAIN DURING WED AS LOW PRESSURE IN THE NORTHERN HIGH
PLAINS ELONGATES ACROSS THE UPPER MIDWEST INTO ONTARIO BY THU.
WINDS MAY REACH GALE FORCE BY WED NIGHT ON NORTHERN LAKE MI...AND
PERSIST INTO THU. THE LOW PRESSURE TROUGH DROPS S ACROSS THE GREAT
LAKES FRI WHILE LOW PRESSURE DEEPENS AS IT MOVES E FROM THE
CENTRAL ROCKIES TO THE CENTRAL PLAINS FRI AND FRI NIGHT. THIS LOW
TURNS NE TO THE MID MS VALLEY SAT AND MOVES INTO THE UPPER GREAT
LAKES SAT NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
225 PM CST SUN DEC 9 2012
.DISCUSSION...
ISSUED 210 PM CST SUN DEC 9 2012
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
COVERAGE OF RAIN ACROSS THE FORECAST AREA EARLY TONIGHT ALONG WITH
TEMPERATURES THE FIRST HALF OF THE UPCOMING WEEK...ARE THE MAIN
FORECAST CONCERNS. USING MORE OF THE NAM-WRF THIS FORECAST PERIOD
ALTHOUGH MODEL DIFFERENCES WERE NEGLIGIBLE.
COLD FRONT IS FORECAST TO PUSH ACROSS THE REGION TONIGHT PUTTING AN
END TO THE RAIN AND BRINGING IN MUCH COLDER WEATHER FOR THE FIRST
HALF OF THE WORK WEEK. THE SNOW ASSOCIATED WITH THE STORM SYSTEM
WILL REMAIN TO OUR NORTH WHILE A SECONDARY BAND OF SHOWERS AND
ISOLATED THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT ACROSS EAST
CENTRAL THRU SOUTHEAST ILLINOIS. THE THUNDER THREAT LOOKS TO BE
QUITE EARLY THIS EVE AND CONFINED ALONG AND SOUTH OF THE I-70
CORRIDOR CLOSER TO THE DEEPER MOISTURE AND BETTER INSTABILITY.
FURTHER TO THE NORTH...FORECAST SOUNDINGS CONTINUE TO INDICATE NOT
MUCH IF ANY ICE PRESENT IN THE UPPER LEVELS OF THE CLOUD...AND IF
THERE WAS ANY...THE LEVELS JUST BELOW IT WERE TOO DRY TO SUPPORT
ANY SNOW THIS EVENING AS THE COLD AIR SWEEPS IN.
ON MONDAY...WITH STRONG CYCLONIC FLOW/LOW LEVEL COLD ADVECTION
INDICATED...ALONG WITH MODELS DEPICTING THE 850 MB THERMAL TROF
PUSHING THRU THE AREA DURING THE LATE MORNING AND EARLY AFTN
HOURS...WE SHOULD SEE PLENTY OF CLOUD COVER AND GUSTY NORTHWEST
WINDS...ALONG WITH SOME FLURRIES...ESP ACRS THE NORTH AND EAST.
THE NAM-WRF AND GFS INDICATES A 500 MB VORT TROF TO SHIFT THRU
THE AREA AS WELL DURING THE AFTN ACCOMPANIED BY SOME COLD TEMPS
ALOFT. FORECAST SOUNDINGS SHOWING SOME DECENT LOW AND MID LEVEL
LAPSE RATES ALONG WITH MORE MOISTURE ABOVE 850 MB THAN PREVIOUS
MODELS FORECAST SO WILL HAVE AT LEAST A CHANCE FOR FLURRIES MAINLY
ACRS THE NORTH AND EAST DURING THE DAY. 500 MB TROF AXIS SHOULD
EXIT TO OUR EAST LATE MONDAY AFTERNOON TAKING ANY FLURRY THREAT
WITH IT. WE SHOULD THEN SEE A DECREASE IN CLOUDS AND WINDS DURING
THE EVENING WITH THE NAM SHOWING THE SURFACE RIDGE AXIS RIGHT OVER
THE FORECAST AREA BY 12Z TUESDAY. AFTER A COLD START TUESDAY MORNING
WE SHOULD SEE A RATHER QUIET WEATHER PATTERN OVER THE MIDWEST THRU
WEDNESDAY NIGHT AS UPPER LEVEL HEIGHTS BUILD OVER THE CENTER OF THE
NATION AS A DEEP TROF DIGS INTO THE ROCKIES.
LONG TERM...THURSDAY THROUGH SUNDAY
THE UPPER FLOW ACROSS THE MIDWEST BECOMES SOUTHWESTERLY AS THE
AFOREMENTIONED TROF SETS UP OVER THE ROCKIES LATE IN THE WEEK. THIS
SHOULD BRING WARMER TEMPERATURES INTO OUR AREA WITH DRY CONDITIONS
HOLDING THRU FRIDAY. THE LATEST OPERATIONAL GFS HAS MADE A SIGNIFICANT
CHANGE FROM ITS PREVIOUS RUNS WITH RESPECT TO THE LATE FRIDAY/SATURDAY
WEATHER SYSTEM IN TAKING TWO SEPARATE SYSTEMS ACROSS THE MIDWEST
RATHER THAN ONE LARGE LOW AT THE SURFACE AND AT 500 MB...WHICH THE
12Z ECMWF CONTINUES TO INDICATE. WILL CONTINUE TO SIDE WITH THE MORE
CONSISTENT ECMWF SOLUTION IN BRINGING RAIN CHANCES INTO OUR AREA
FRIDAY NIGHT AND CONTINUING AT LEAST A CHANCE OF RAIN ON SATURDAY.
THE ECMWF HAS TRENDED A BIT SLOWER WITH ITS TRACK ACRS THE MIDWEST
ON SATURDAY SO WILL KEEP AT LEAST SLIGHT CHANCES GOING INTO SATURDAY
EVENING OVER THE EASTERN TWO-THIRDS OF THE FORECAST AREA.
ACTIVE PATTERN SHOULD HOLD AFTER OUR WEEKEND SYSTEM MOVES OUT AS ANOTHER
STRONG UPPER WAVE IS FORECAST TO GET EJECTED ENE OUT OF THE MEAN
LONGWAVE TROF POSITION OVER THE ROCKIES. THIS SHOULD BRING ANOTHER
STORM SYSTEM NORTHEAST INTO THE MIDWEST...ALTHOUGH THE LATEST ECMWF
IS INDICATING THE STRONGEST CORE OF WINDS AT 250 MB STILL ON THE WEST
SIDE OF THE TROF LATE NEXT WEEKEND...SUGGESTING THIS WAVE MAY DIG MORE
THAN ITS PREDECESSOR AND TAKE A MORE SOUTHERLY TRACK. ANY WEATHER
ASSOCIATED WITH THIS SHORTWAVE WILL OCCUR BEYOND THIS FORECAST PERIOD.
WITH THE UPPER FLOW FORECAST TO REMAIN SOUTHWEST THRU NEXT WEEKEND...
NO SIGNS OF ANY SIGNIFICANT BUCKLING OF THE JET TO ALLOW A PROLONGED
PERIOD OF COLD INTO THE MIDWEST...OTHER THAN THE BRIEF COOL OFFS BEHIND
THESE SOUTHWEST SYSTEMS.
SMITH
&&
.AVIATION...
ISSUED 1059 AM CST SUN DEC 9 2012
CEILINGS REMAIN THE PRIMARY CONCERN FOR THIS TAF SET. CENTRAL
ILLINOIS TAF SITES CURRENTLY AROUND 300-400 FEET...WITH VISIBILITY
OF 1 TO 2SM. SOME MODEST IMPROVEMENTS EXPECTED AFTER A FRONTAL
BOUNDARY CURRENTLY IN EASTERN MISSOURI PUSHES THROUGH OUR AREA...
GENERALLY CROSSING THE TAF SITES IN THE 19-22Z TIME FRAME. VISIBLE
SATELLITE IMAGERY SHOWING A CLEARING LINE EXTENDING NORTH AND
SOUTHWEST FROM KANSAS CITY. AWIPS TIME-OF-ARRIVAL TOOL WOULD PLACE
IT AROUND KPIA/KSPI TOWARD 23Z IF IT HOLDS TOGETHER...HOWEVER THE
LOW LEVEL HUMIDITY PLOTS OFF THE RAP AND NAM MODELS SUGGEST ONLY
SOME TEMPORARY BREAKS IN THE CEILING BY THAT POINT...SO WILL
MAINTAIN MVFR CEILINGS FOR NOW. CIRCULATION AROUND THE DEPARTING
STORM SYSTEM EXPECTED TO BRING ANOTHER SLUG OF STRATOCUMULUS
OVERNIGHT...PERSISTING MUCH OF THE MORNING...WITH CEILINGS
REMAINING BELOW 3000 FEET THROUGH MONDAY MORNING.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1115 AM CST SUN DEC 9 2012
.DISCUSSION...
ISSUED 1000 AM CST SUN DEC 9 2012
FIRST WAVE OF PRECIPITATION HAS LARGELY LIFTED OUT OF THE FORECAST
AREA...WITH SOME RESIDUAL SHOWERS/DRIZZLE LINGERING...ESPECIALLY
ACROSS THE NORTH. SHOWERS AND SCATTERED THUNDERSTORMS ACROSS
SOUTHERN MISSOURI EXPECTED TO FOLLOW A WAVE OF ENERGY LIFTING
NORTHEAST OUT OF NORTHERN ARKANSAS...AND WILL POSE A THREAT TO
AREAS SOUTH OF I-70 BY EARLY AFTERNOON. THE REMAINDER OF THE
FORECAST AREA WILL ONLY SEE SCATTERED SHOWERS DURING THE AFTERNOON
HOURS.
HAVE UPDATED THE ZONES/GRIDS FOR THE LATEST RAIN TRENDS. TEMPERATURES
WERE LARGELY IN GOOD SHAPE AND NEEDED LITTLE MODIFICATION.
GEELHART
&&
.AVIATION...
ISSUED 1059 AM CST SUN DEC 9 2012
CEILINGS REMAIN THE PRIMARY CONCERN FOR THIS TAF SET. CENTRAL
ILLINOIS TAF SITES CURRENTLY AROUND 300-400 FEET...WITH VISIBILITY
OF 1 TO 2SM. SOME MODEST IMPROVEMENTS EXPECTED AFTER A FRONTAL
BOUNDARY CURRENTLY IN EASTERN MISSOURI PUSHES THROUGH OUR AREA...
GENERALLY CROSSING THE TAF SITES IN THE 19-22Z TIME FRAME. VISIBLE
SATELLITE IMAGERY SHOWING A CLEARING LINE EXTENDING NORTH AND
SOUTHWEST FROM KANSAS CITY. AWIPS TIME-OF-ARRIVAL TOOL WOULD PLACE
IT AROUND KPIA/KSPI TOWARD 23Z IF IT HOLDS TOGETHER...HOWEVER THE
LOW LEVEL HUMIDITY PLOTS OFF THE RAP AND NAM MODELS SUGGEST ONLY
SOME TEMPORARY BREAKS IN THE CEILING BY THAT POINT...SO WILL
MAINTAIN MVFR CEILINGS FOR NOW. CIRCULATION AROUND THE DEPARTING
STORM SYSTEM EXPECTED TO BRING ANOTHER SLUG OF STRATOCUMULUS
OVERNIGHT...PERSISTING MUCH OF THE MORNING...WITH CEILINGS
REMAINING BELOW 3000 FEET THROUGH MONDAY MORNING.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 245 AM CST SUN DEC 9 2012
SHORT TERM...TODAY THROUGH TUESDAY
LOW PRESSURE CURRENTLY OVER OKLAHOMA WILL TRACK NORTHEASTWARD
TODAY...EVENTUALLY REACHING CENTRAL INDIANA BY EARLY EVENING. THIS
PARTICULAR TRACK WILL KEEP MUCH OF THE KILX CWA ON THE COOL SIDE
OF THE SYSTEM...WHILE AREAS ALONG/SOUTH OF THE I-70 CORRIDOR PUNCH
INTO THE WARM SECTOR DURING THE AFTERNOON. ISENTROPIC UPGLIDE NOTED
ON THE 295K SURFACE WILL BECOME NEUTRAL AS THE WEAK LOW PRESSURE
CENTER MOVES INTO THE VICINITY TOWARD MIDDAY. AS A RESULT...THINK
SHOWERS WILL BE MOST WIDESPREAD THROUGH 15Z/9AM...BEFORE MAIN PRECIP
AREA SHIFTS FURTHER NORTHEAST. WILL THEREFORE CARRY CATEGORICAL
POPS THIS MORNING...THEN JUST CHANCE POPS ACROSS MUCH OF THE AREA
THIS AFTERNOON. THE EXCEPTION WILL BE ALONG/SOUTH OF I-70...WHERE
MODELS TRY TO DEVELOP ADDITIONAL SHOWERS IN THE WARM SECTOR LATER
IN THE DAY. MAY EVEN BE A FEW ISOLATED THUNDERSTORMS ACROSS THE
FAR SE CWA...COURTESY OF DEWPOINTS IN THE LOWER 50S AND LIFTED
INDEX VALUES APPROACHING 0C. HIGH TEMPERATURES WILL BE QUITE
VARIABLE TODAY...RANGING FROM THE MIDDLE 40S IN THE ILLINOIS RIVER
VALLEY...TO THE LOWER 60S SOUTH OF I-70.
AS LOW TRACKS INTO CENTRAL INDIANA...WINDS WILL SWITCH TO THE
NORTHWEST...ALLOWING A MUCH COLDER AIR MASS TO FILTER INTO THE AREA
TONIGHT. 00Z DEC 9 MODELS ARE NOW INDICATING THAT THE COLD AIR
WILL LAG BEHIND THE DEPARTING MOISTURE JUST ENOUGH TO PREVENT ANY
CHANGE OVER FROM LIGHT RAIN SHOWERS TO SNOW SHOWERS. WILL LINGER A
FEW RAIN SHOWERS THROUGH THE EVENING EAST OF I-55...THEN WILL GO
MAINLY DRY OVERNIGHT. LOW TEMPERATURES WILL RANGE FROM THE LOWER
20S AROUND GALESBURG...TO THE MIDDLE 30S NEAR LAWRENCEVILLE.
BELOW NORMAL TEMPS WILL TAKE HOLD ACROSS THE MIDWEST FOR MONDAY
AND TUESDAY...AS CANADIAN HIGH PRESSURE DOMINATES THE WEATHER.
HIGHS BOTH DAY WILL REMAIN IN THE 30S...WHILE LOWS DIP INTO THE
TEENS MONDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY
UPPER TROUGHING WILL RELAX BY MID-WEEK...FOLLOWED BY A RETURN TO
ZONAL FLOW. END RESULT WILL BE MODERATING TEMPERATURES THROUGH THE
BALANCE OF THE WEEK...WITH HIGHS CLIMBING INTO THE UPPER 40S AND
LOWER 50S BY FRIDAY AND SATURDAY. BOTH THE ECMWF AND GFS MAINTAIN
DRY CONDITIONS THROUGH FRIDAY...BUT THEN BRING NEXT SIGNIFICANT
SHORT-WAVE INTO THE REGION OVER THE WEEKEND. GIVEN GOOD MODEL
AGREEMENT...WILL CARRY HIGH CHANCE POPS FOR RAIN FRIDAY NIGHT INTO
SATURDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
731 PM EST MON DEC 10 2012
.UPDATE...
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO BE THE PRIMARY SHORT
TERM CONCERN. SFC TROUGH WHICH BROUGHT A PERIOD OF SNOW AND EVEN
SOME LIGHT RAIN TO NORTHERN SECTIONS OF FORECAST AREAS NOW APPEARS
TO EXTEND FROM A LINE FROM SOUTHERN LA PORE COUNTY EXTENDING
EASTWARD ALONG THE ROUTE 30 CORRIDOR. LIGHT SNOW PERSISTS ALONG
THIS CONVERGENCE AXIS WITH SNOWFALL AMOUNTS GENERALLY LESS THAN A
HALF INCH OBSERVED AS THIS AREA HAS DROPPED SOUTHWARD. LAKE EFFECT
SNOW SHOWERS HAVE INCREASED SIGNIFICANTLY OVER PAST TWO HOURS
ACROSS FAR EASTERN LAKE MICHIGAN WHERE THERMALLY INDUCED SFC
CONVERGENCE APPEARS TO BE AIDING IN FOCUSING LAKE EFFECT SNOW
SHOWERS. LAKE EFFECT PARAMETERS STILL APPEAR TO BE QUITE FAVORABLE
FOR A SHORT PERIOD OF MORE SIGNIFICANT LAKE EFFECT SNOW SHOWERS
ESPECIALLY IN THE 03Z-08Z TIMEFRAME...WHEN INVERSION HEIGHTS RISE
TO NEAR 7500 FT...AND LAKE INDUCED EQUILIBRIUM LEVELS REACH NEAR
13K FT. ORIENTATION OF THERMALLY INDUCED SFC TROUGH WOULD SUGGEST
THAT BERRIEN/WESTERN CASS COUNTY INLINE TO SEE MORE SIGNIFICANT
LAKE EFFECT SNOW SHOWERS...AND POSSIBLY EXTENDING INTO NORTH
CENTRAL/NORTHEAST PORTIONS OF LA PORTE COUNTY.
SECONDARY BAND ALSO APPEARS TO BE DEVELOPING WEST OF MICHIGAN CITY
WHICH APPEARS TO BE AIDED BY LARGER SCALE LOW LEVEL CONVERGENCE
FROM REMNANTS OF SLOW MOVING SFC TROUGH. LONGEVITY OF A FAVORABLE
WIND FIELD APPEARS MORE QUESTIONABLE WITH THIS BAND HOWEVER WITH
STRONGER CONVERGENCE LIKELY REMAINING ANCHORED CLOSER TO THE
EASTERN SHORELINE. GIVEN LINGERING UNCERTAINTIES AS TO HOW BANDING
WILL UNFOLD THE REMAINDER OF THE EVENING...HAVE MAINTAINED A
BROADBRUSH 1 TO 3 INCH MENTION IN FORECAST AND WILL HOLD OFF ON
ANY HEADLINES AT THIS TIME...ALTHOUGH IF HEADLINES ARE NEEDED IT
APPEARS AS THOUGH BERRIEN COUNTY WOULD HAVE A GREATER RISK AT
REACHING LOCALIZED ADVISORY LEVEL AMOUNTS. IT STILL APPEARS AS
THOUGH THERMAL CONVERGENCE SHOULD BEGIN TO BREAK DOWN AFTER
09Z...AS LARGE SCALE SYNOPTIC WINDS BEGIN TO FAVOR MORE WESTERLY
DIRECTIONS ALSO ACTING TO LIMIT FETCH AND LAKE SUPERIOR CONNECTION.
&&
.AVIATION...
00Z TAFS...AREA OF LIGHT SNOW SHOWERS ACCOMPANYING SFC TROUGH HAS
DROPPED SOUTH OF KSBN AND SHOULD REACH KFWA BY 02Z WITH A PERIOD
OF LIGHT SNOW AT THAT TERMINAL. CURRENT IFR CONDITIONS AT KFWA
SHOULD IMPROVE TO MVFR OVER THE NEXT FEW HOURS DUE TO THE
CONTINUED SOUTHWARD PROGRESSION OF SFC TROUGH. MEANWHILE...LAKE
EFFECT SNOW SHOWERS ARE ON THE INCREASE PER REGIONAL RADAR MOSAIC
ACROSS FAR EASTERN PORTIONS OF LAKE MICHIGAN WHERE A WEAK SFC
TROUGH APPEARS TO BE DEVELOPING. IT STILL APPEARS AS THOUGH KSBN
SHOULD BE INLINE FOR PERIODS OF LAKE EFFECT SNOW SHOWERS
ESPECIALLY IN THE 04Z-08Z TIMEFRAME WHEN PERIODIC LIFR CONDITIONS
ARE POSSIBLE WITH THE HEAVIER SNOW BURSTS. LAKE EFFECT SNOW TO
QUICKLY WIND DOWN TOWARD 10Z AS LOW LEVEL WINDS BACK MORE
WESTERLY. TREND TO VFR CONDITIONS EXPECTED BY MID MORNING WITH
INCREASING SOUTHWEST WINDS INTO THE 10 TO 15 KNOT RANGE.
&&
.PREV DISCUSSION... /ISSUED 247 PM EST MON DEC 10 2012/
SHORT TERM...
DIFFICULT PD EARLY ON GIVEN SCOPE OF DVLPG LK RESPONSE. SFC TROUGH
ACRS NRN CONTS TO DROP SWD AND EMBOLDENING A BROADER RESPONSE
UNDERNEATH BALLOONING MID LVL MSTR PLUME. BRIEF PD OF FZDZ AND
PERHAPS SLEET AT ONSET BUT QUICKLY CHANGING OVR TO SHSN N-S TIMED
W/ARRIVAL OF LK MSTR ENTRAINMENT PLUME AND DEEPENING CAA WEDGE.
PRIMARY PROB THIS EVENING IS TEA KETTLE LK SETUP AND DENOTED QUITE
WELL IN RUC13 AND OTHER HIGHRES GUIDANCE. LK SP CONNECTION NOTED
THIS AFTN WITHIN FVRBLY VEERED LONG AXIS CYCLONIC FETCH AS SEEN IN
VIS IMAGERY AND SUSPECT LK CONVERGENCE ZONE WILL ABRUPTLY BLOSSOM
AFT SUNSET IN TANDEM W/MAXIMIZING LL THERMAL TROUGH OF WHICH MAY
LEAD TO A BRIEF PD OF SIG LK EFFECT SNOWFALL CNTRD THROUGH EXTREME
SW BERRIEN...NRN LAPORTE AND WRN ST JOE COUNTIES. TEMPTED TO
CONSIDER AN ADVISORY BUT GIVEN UPSTREAM LK DVLPMNTS HAVE YET TO
PLAY THEIR CARD...CONFIDENCE LACKING. WILL CONT TO MONITOR AND
PASS CONCERNS ONWARD.
OTRWS LG SCALE SFC RIDGE WILL BUILD ALG THE APPALACHIAN SPINE
THROUGH THE END OF THE PD AS WK SECONDARY SYS DIPS THROUGH SRN
ONTARIO. LL FLW BACKS ABRUPTLY LT TONIGHT TO WRLY W/DWINDLING LK
EFFECT LIFTING OUT BFR BACKING FURTHER TO SWRLY ON TUE. THIS WILL
YIELD SW-NE CLRG W/SOME INSOLATION HELPING TO BOOST TEMPS A BIT
WARMER THAN TDA.
LONG TERM...WEDNESDAY THROUGH MONDAY.
ENERGY CURRENTLY IN THE GULF OF ALASKA WILL DIG ALONG THE PACIFIC
COAST THROUGH THE UPCOMING WEEK...REACHING CALIFORNIA BY THURSDAY.
THIS WILL ALLOW FOR INCREASING HGTS WITH A SEMI ZONAL FLOW TO SET UP
THROUGH FRIDAY. TEMPS ARE EXPECTED TO MODERATE TO ABOVE NORMAL
LEVELS IN THE 40S.
LEE SIDE CYCLOGENESIS WILL TAKE PLACE STARTING LATE FRIDAY WITH THE
SYSTEM EJECTING TOWARDS THE GREAT LAKES. MODELS VARYING SOMEWHAT ON
TIMING AND OVERALL TRACK...BUT SEEM TO POINT TOWARDS THE FORECAST
AREA BEING ON THE WARM SIDE ONCE AGAIN...YIELDING RAIN CHANCES FOR
THE WEEKEND FOLLOWED BY A MIXTURE OF RAIN/SNOW IN ITS WAKE. PREV
GRIDS HAD DECENT HANDLE ON TRENDS. ONLY CHANGES MADE WAS TO BREAK UP
WITH SOMEWHAT MORE DETAIL TO TRY TO ADD SOME TIMING TO BETTER
CHANCES OF PRECIP. QUICK SHOT OF COLD AIR WILL ARRIVE BEHIND THE
SYSTEM...BUT NOTHING SUBSTANTIALLY COLDER WITH A RETURN TO NEAR OR
SLIGHTLY BELOW NORMAL READINGS.
ENERGIZED PATTERN WILL CONTINUE OUTSIDE THE LONG TERM PERIOD WITH
NEXT SYSTEM ALREADY TAKING SHAPE OVER TEXAS BY MONDAY NIGHT. ECMWF
OVER THE PAST SEVERAL RUNS HAS HINTED THAT THIS COULD BRING A DECENT
SHOT OF ACCUMULATING SNOWFALL TO THE REGION BOTH IN ADVANCE OF THE
SYSTEM AND WITH WHAT COULD BE A PERSISTENT DEFORMATION ZONE AS THE
LOW CUTS OFF SOMEWHERE IN THE EASTERN GREAT LAKES. PLENTY OF TIME TO
WATCH AT THIS POINT CONSIDERING STILL A WAYS TO GO.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...FISHER
UPDATE...MARSILI
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1138 PM CST SAT DEC 8 2012
.UPDATE...
ADDED 06Z TAF DISCUSSION.
NO BIG CHANGES WITH EVENING UPDATE BUT HAVE NUDGED UP THE SNOW
AMOUNTS NE IN THE MASON CITY AND WATERLOO AREAS. SMALL AREA OF
PRECIP THAT MOVED THROUGH CENTRAL IA RECENTLY WAS MAINLY RAIN AT THE
AIRPORT...BUT PRIMARILY SNOW JUST TO THE NORTH HERE AT THE
OFFICE...AT BOONE AND AMES. MAINLY MELTED BUT JUST STUCK A LITTLE
IN SOME AREAS. EXPECT THIS TO CONTINUE AS IT WORKS NE LATER TONIGHT
AS 02Z RAP 2.5KM LAYER MAX WET BULB TEMP CHANGES LITTLE OVERNIGHT.
THIS SUGGESTS CURRENT SNOW AND RAIN/SNOW LINES ARE A TAD TOO FAR
NORTH AND HAVE SHIFTED THEM A BIT SOUTHWARD RESULTING IN A HALF INCH
OR MORE INCREASE IN SNOW AMOUNTS THERE. LATEST NAM...DEV HRRR AND
WRF RUNS ALL SUGGEST LOBE OF FORCING CURRENTLY PRODUCING PRECIP FROM
SW MN INTO IA WILL FURTHER SATURATE AND THEN PHASE WITH MATURING
SERN IA PRECIP WITH MORE WIDESPREAD COVERAGE OVER NERN IA TOWARD
DAYBREAK.
&&
.SHORT TERM /TONIGHT/...
BAND OF STRONG THETA-E ADVECTION IS MOVING INTO WESTERN IOWA THIS
AFTERNOON AND WILL CONTINUE TO MOVE ACROSS THE STATE THIS EVENING.
RADAR ECHOES HAVE BEEN INTENSIFYING WITH THIS MID LEVEL FORCING FROM
SOUTHWEST IOWA THROUGH SOUTHEAST SOUTH DAKOTA AND AT THIS
TIME...ONLY PRECIPITATION REPORTS ARE FROM THE NORTHERN EDGE WITH
CLOUD HEIGHTS REMAINING AOA 7KFT FARTHER SOUTH. EXPECT SOME LIGHT
PRECIPITATION TO FALL OVER THE NORTHWEST THIRD TO HALF THIS EVENING
ALONG THE INITIAL MOISTURE SURGE. SOME OF THIS PRECIPITATION COULD
BE LIGHT SNOW GIVEN WETBULB PROFILES AS FAR SOUTH AS HIGHWAY 30
THOUGH NO ACCUMULATIONS ARE EXPECTED THIS EVENING EXCEPT FOR
POSSIBLY THE FAR NORTH. A SECONDARY THETA-E SURGE WILL FOLLOW AFTER
MIDNIGHT. THIS WILL HELP KEEP LOW LEVEL TEMPERATURES ABOVE FREEZING
OVER THE CENTRAL AND SOUTH AND KEEP WETBULBS IN THE LOWEST
1500-2500FT 34F OR HIGHER. THIS LAYER WILL BE ENOUGH TO MELT ANY
SNOW THROUGH THIS REGION. COLDER PROFILES YET NORTH WHERE
PRECIPITATION WILL BE EXPANDING WITH THE ARRIVAL OF INCREASING
KINEMATICS WITH THE APPROACH OF THE UPPER LEVEL SHORT WAVE. THE
PRECIPITATION WILL BE ALL SNOW OVER THE NORTH. EXPECT SEASONAL TO
SLIGHTLY HIGHER SNOW RATIOS OVER THE NORTH OF 13-15 TO 1 AND COULD
HAVE ACCUMULATIONS BY 12Z OF 0.5 TO 1.5 INCHES ALONG AND NORTH OF A
DENISON TO FORT DODGE TO WAVERLY LINE. NON-DIURNAL TEMPERATURE
TRENDS OVERNIGHT WITH HIGHER DEWPOINTS MOVING INTO THE STATE.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THERE ARE TWO SYSTEMS TO FOCUS ON IN THE EXTENDED. THE FIRST IS THE
SYSTEM FROM TONIGHT THAT WILL BE QUICKLY PUSHING ACROSS THE CWA
DURING THE MORNING HOURS FOLLOWED BY STRONG COLD ADVECTION.
SOUNDINGS AT 12Z SHOW TEMPERATURES AT OR JUST ABOVE FREEZING ACROSS
THE FORECAST AREA. A COLD FRONT WILL SWEEP THE CWA THROUGH THE
MORNING AND SOUNDING LOCATIONS WEST OF I-35 DRY OUT BEHIND THE FRONT
WITH TEMPERATURES FALLING THROUGHOUT THE LATE MORNING AND THE REST
OF THE DAY. FORCING WEAKENS THROUGHOUT THE DAY BUT POCKETS OF
BETTER FORCING REMAIN ACROSS CENTRAL IOWA THROUGH MOST OF THE DAY.
THE PROBLEM IS THAT WE LOSE OUR DEEPER MOISTURE QUICKLY IN THE
MORNING. AS A RESULT...I AM NOT LOOKING FOR MUCH IN THE WAY OF
PRECIPITATION/SNOW ACCUMULATION OUT OF THIS SYSTEM. WE COULD SEE A
COUPLE OF INCHES ACROSS THE NORTH AT BEST WITH TRACE AMOUNTS
ELSEWHERE AS PRECIP TRANSITIONS TO SNOW BEFORE ENDING. THE SURFACE
LOW IS TOO FAR NORTH AND THE UPPER WAVE IS NOT DEEP ENOUGH TO DO
MUCH MORE THAN THAT. WINDS ON THE OTHER HAND MAY BE PROBLEMATIC
SUNDAY...ESPECIALLY COMBINED WITH THE COLD AIR MOVING IN. WIND
CHILLS WILL FALL INTO THE TEENS DURING THE AFTERNOON.
TUESDAY THROUGH THURSDAY...THERE WILL BE A LONG WAVE TROUGH PASSING
ACROSS THE REGION WITH A RIDGE BUILDING INTO THE WEST TUESDAY AND
SHIFTING ACROSS THE MIDWEST THROUGH THURSDAY AS A LARGE TROUGH
CARVES OUT OVER THE WEST. THIS WILL BE A PLAYER IN OUR WEATHER INTO
THE WEEKEND.
THEN LATER IN THE WEEK...IN THE FRIDAY TO SATURDAY NIGHT TIME FRAME
A SECOND POTENTIALLY STRONG SYSTEM WILL AFFECT CENTRAL IOWA. THERE
ARE SIGNIFICANT DIFFERENCES BETWEEN THE MODELS...AT LEAST INITIALLY
AS TO THE EVOLUTION OF THE UPPER LEVEL WAVE...THE SURFACE LOW AND
THE FRONTAL BOUNDARY WITH THE SYSTEM. THE GFS LEAVES THIS AN OPEN
WAVE THROUGH FRIDAY THEN DEVELOPS A LOW OVER SOUTH DAKOTA AS THE
SYSTEM WRAPS UP WHILE THE EURO DEVELOPS A DEEP LOW OVER KANSAS AND
LIFTS IT NORTHEAST. BOTH MODELS PUT THE UPPER LOW OVER SE MN AT 00Z
BUT HOW IT GETS THERE IS AN QUESTION. THE EURO DEVELOPS A MUCH
BETTER DEFORMATION ZONE OVER NORTHERN INTO WEST CENTRAL IOWA WHILE
THE GFS HAS THIS FURTHER NORTH.
THE SURFACE LOW POSITION IS ALSO QUITE DIFFERENT IN PLACEMENT AND
INTENSITY. BOTH MODELS POINT AT SOUTHERN IOWA AND LOCATIONS SOUTH
AND EAST BEING IN A WARM ADVECTION ZONE WITH PRETTY IMPRESSIVE CAPE
FOR MID DECEMBER. THEREFORE I HAD TO PUT IN ISOLATED THUNDER ACROSS
THE SOUTH. PTYPE ELSEWHERE IS VERY DIFFICULT TO PINPOINT AT THIS
POINT. THE NORTH INTO WEST CENTRAL COULD HAVE A MIXED BAG OF PRECIP
CHANGING TO SNOW AND ACCUMULATING. A RAIN/SNOW TRANSITION WILL
OCCUR BETWEEN THERE AND SOUTH BUT THERE IS NOT ENOUGH AGREEMENT
BETWEEN THE MODELS TO SAY WITH ANY CERTAINTY. AT THIS POINT IT
LOOKS MESSY WITH A POTENTIAL FOR SEVERAL PTYPES ACROSS IOWA AND
THUNDER SOUTH. HOWEVER THE MODELS DID SOMETHING SIMILAR WITH THIS
CURRENT SYSTEM AT THAT FAR OUT.
&&
.AVIATION...09/06Z
CONDITIONS HAVE DETERIORATED THIS EVENING AND NOW MAINLY VARY FROM
LIFR-MVFR. ALTHOUGH PATCHY LIGHT PRECIP WILL CONTINUE JUST AFTER
MIDNIGHT ADDITIONAL PRECIP IS EXPECTED DEVELOP AFTER 09Z IN
KMCW/KALO AREA...MAINLY IN THE FORM OF SNOW. ONCE THIS OCCURS MANY
LOCATIONS WILL LIKELY DIP TO LIFR OR AT LEAST IFR. PRECIP SHOULD
END 14-16Z FOLLOWED BY WINDS BECOMING NW WITH GUSTS INTO THE 20S
INTO THE AFTERNOON AND EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...DONAVON
LONG TERM...FAB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
310 PM CST SUN DEC 9 2012
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH FROM THE FOUR
CORNERS REGION INTO THE DAKOTAS. ONE SHORTWAVE WAS LIFTING
NORTHEAST INTO MN WITH ANOTHER SHORTWAVE OVER THE CO AND NM
ROCKIES. AT THE SURFACE...A VERY STRONG COLD FRONT HAS PUSHED
SOUTH INTO NORTH TX AND EAST INTO CENTRAL MO. AREA OBSERVATIONS
INDICATE STRONG COLD AND DRY AIR ADVECTION IS ONGOING. RADAR
TRENDS THROUGHOUT THE DAY HAVE SUPPORTED THE IDEA THAT THE DRY AIR
NEAR THE SURFACE IS TO MUCH FOR WEAK FRONTOGENESIS IN THE MID
LEVELS TO OVERCOME.
FOR TONIGHT AND MONDAY...MODELS SHOW LITTLE OR NO LARGE SCALE
FORCING THROUGH THE PERIOD WITH THE ONLY INDICATION OF FORCING FOR
PRECIP BEING WEAK MID LEVEL FRONTOGENESIS THROUGH THE EARLY EVENING.
GIVEN THE CONTINUED ADVECTION OF DRY AIR IN THE LOWER TROPOSPHERE...
THINK PRECIP CHANCES ARE PRETTY CLOSE TO NIL. BY MONDAY...THE COLD
SURFACE RIDGE OF HIGH PRESSURE WITH VERY DRY AIR IS EXPECTED TO
DOMINATE THE WEATHER AS THE SHORTWAVE OVER THE SOUTHERN ROCKIES
PASSES MAINLY TO THE SOUTH OF THE FORECAST AREA. THEREFORE THE
FORECAST WILL REMAIN DRY. ABOUT THE ONLY WEATHER CONCERN IS CLOUD
COVER OVERNIGHT. VISIBLE SATELLITE SHOWS AN AREA OF STRATOCU MOVING
SWIFTLY SOUTH ACROSS EASTERN NEB. THE RAP SHOWS THIS DECK OF LOW
CLOUDS HANGING IN ACROSS NORTHEAST AND EAST CENTRAL KS THROUGH MUCH
OF THE NIGHT...AND THE NAM AND GFS TO A LESSER EXTENT SUPPORT THE
IDEA. SO THINK SKIES WILL BE MOSTLY CLOUDY TONIGHT. BECAUSE OF THIS
HAVE KEPT LOWS A DEGREE OR TWO WARMER THAN THE MOS GUIDANCE ACROSS
EASTERN KS. ADDITIONALLY A STRONGLY MIXED BOUNDARY LAYER SHOULD HELP
KEEP LOWS FROM PLUMMETING. NORTH CENTRAL KS COULD SEE SINGLE DIGIT
LOWS WHERE SKIES SHOULD CLEAR OUT SOONER. WITH SUCH A COLD START TO
THE DAY...HIGHS ARE EXPECTED TO ONLY MAKE IT INTO THE LOWER AND MID
30S FOR MONDAY EVEN WITH MOSTLY SUNNY SKIES.
WOLTERS
MID WEEK PERIODS LOOKING RATHER BENIGN. SOME MID AND HIGH CLOUDS
SHOULD BE ALL THAT RESULTS FROM THE NEXT UPPER WAVE PASSING THROUGH
THE CENTRAL PLAINS MONDAY NIGHT INTO EARLY TUESDAY. LOW LEVEL FLOW
REMAINS MAINLY WESTERLY TUESDAY FOR WEAK WARM AIR ADVECTION...AND
WAA INCREASES INTO WEDNESDAY AND THURSDAY AS BROAD RIDGING OVERTAKES
THE CENTRAL AND EASTERN CONUS. THE DEGREE OF MIXING INTO THE WARM
AND DRY MID LEVELS IS THE MAIN QUESTION FOR HOW WARM HIGHS WILL GET.
BUMPED THEM UP A FEW DEGREES AT THIS POINT BUT FURTHER INCREASES MAY
BE NEEDED. SSW WINDS INCREASE FOR WEDNESDAY INTO THURSDAY AND
RELATIVE HUMIDITIES MAY DROP TO LEVELS OF SOME CONCERN FOR FIRE
WEATHER MAINLY ON WEDNESDAY.
MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH WESTERN TROF AND
UPPER LOW IN THE SOUTHWEST CONUS ON THURSDAY...BUT DIFFERENCES
MAGNIFY QUICKLY INTO THE WEEKEND. THE 12Z ECMWF PUSHES THE LOW EAST
AHEAD OF THE NORTHERN TROF AND ALLOWS A LOW TO RE-CLOSE AND DEEPEN
RAPIDLY OVER THE CENTRAL PLAINS...WHILE THE 12Z GFS KEEPS THE
SOUTHERN LOW BEHIND THE NORTHERN TROF FOR A WEAKENING WAVE IN THE
PLAINS. MODERATE PRECIPITATION CHANCES REMAIN...CENTERED AROUND
FRIDAY NIGHT...WITH SOME OPPORTUNITY FOR CONVECTION IN THE MORE
AMPLIFIED SOLUTIONS AND MINOR CONCERN FOR WINTRY PRECIP AS THE EVENT
WINDS DOWN. TEMPS SHOULD RETURN TO NEAR MID-DECEMBER NORMALS FOR
SUNDAY.
65
&&
.AVIATION...
LATEST OBS AND RADAR SHOWING LOW LEVEL DRY AIR WINNING OUT OVER THE
WEAK FORCING...AND MODELS SHOW THESE CONDITIONS PERSISTING THROUGH
THE AFTERNOON. THERE IS ONE LITTLE PATCH OF STRATOCU SEEN ON
SATELLITE NEAR TOP AND FOE WHICH WILL BE OUT SHORTLY. OTHERWISE VFR
CONDITIONS SHOULD PREVAIL INTO THE EARLY EVENING. MODELS DO HINT AT
SOME MVFR CIGS MOVING SOUTH THROUGH EASTERN NEB OVERNIGHT. THEREFORE
HAVE CONTINUED THE PREV FORECAST OF CIGS BETWEEN 2 AND 3 KFT
OVERNIGHT. WINDS WILL REMAIN UP DUE TO A STRONG PRESSURE GRADIENT.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1205 PM CST SUN DEC 9 2012
.UPDATE...
FALLING TEMPERATURES ARE ANTICIPATED THROUGH THE AFTERNOON HOURS ACROSS
MUCH OF CENTRAL AND SOUTHEAST KANSAS WITHIN STRONG LOW-LEVEL CAA POST-
FRONTAL REGIME. WINDS MAY FLIRT WITH ADVISORY CRITERIA BRIEFLY...ESPECIALLY
ACROSS CENTRAL KANSAS HOWEVER DUE TO THE SHORT DURATION NO
HEADLINES ARE ANTICIPATED. VERY DRY IS ALSO BEING ADVECTED THROUGH
THE PBL DECREASING THE PROBABILITY FOR SEEING ANY SNOW FLURRIES SO
MAINTAINED A DRY FORECAST THROUGH THE OVERNIGHT PERIOD.
MWM
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
NORTHWEST WINDS AROUND 25 KNOTS WITH GUSTS INTO THE 30-35 KNOT
RANGE ARE EXPECTED BEHIND A STRONG COLD FRONT. THE WINDS WILL
LIKELY STAY UP INTO THE EVENING HOURS BEFORE DIMINISHING TOWARD
MORNING. MID CLOUDS IN THE 7-10K FT RANGE WILL GRADUALLY CLEAR
OVERNIGHT WITHIN A VERY DRY AND SUBSIDENT AIRMASS BUILDING INTO
THE AREA.
&&
.PREV DISCUSSION... /ISSUED 527 AM CST SUN DEC 9 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS LIFR/IFR CONDITIONS AHEAD OF
THE FRONT AND THEN STRONG GUSTY WINDS BEHIND THE FRONT TODAY.
THE COLD FRONT IS THROUGH MUCH OF KANSAS...BUT THE STRONGER WINDS
ARE JUST REACHING KRSL AS OF 11Z. WINDS WILL ONLY CONTINUE TO GET
STRONGER THROUGHOUT THE DAY WITH 20-25 KTS GUSTING TO 30-35
EXPECTED ACROSS ALL TERMINALS TODAY. WINDS WILL DECREASE
SOME...BUT STAY BREEZY OVERNIGHT.
AHEAD OF THE FRONT LIFR AND IFR CONDITIONS DOMINATE UNDER LOW
STRATUS. AS THE DRIER/COOLER AIR MOVES IN BEHIND THE FRONT...LOW
STRATUS IS SCATTERING OUT WITH A MID LEVEL CLOUD DECK OVERHEAD.
HAVE REMAINED PESSIMISTIC WITH THE FORECAST AT SITES THAT ARE
AHEAD OF THE FRONT...KICT/KCNU KEEPING THEM IN LIFR UNTIL THE
EXPECTED FRONTAL PASSAGE...ALTHOUGH IT MAY BE OFF AND ON WITH
RAGGED CEILINGS ACROSS THE AREA. SKIES WILL BEGIN TO CLEAR
OVERNIGHT FROM KRSL TO KICT UNDER HIGH PRESSURE.
WHILE THERE IS STILL A HINT OF SOME PRECIPITATION WITH THIS
SYSTEM...CONFIDENCE IS LOW THAT ANY WILL ACTUALLY REACH THE
GROUND. THERE IS DECENT LIFT IN THE MID-LEVELS...BUT THE LOWEST
8-12 KFT ARE VERY DRY AND WOULD EXPECT ANY PRECIPITATION THAT DOES
FALL TO EVAPORATE. THAT BEING SAID...CANNOT RULE OUT SOME DRIZZLE
AHEAD OF THE FRONT...AND SOME FLURRIES BEHIND THE FRONT. DID LEAVE
MENTION OF FLURRIES OUT OF THE FORECAST AT ALL TERMINALS BECAUSE
OF THIS. ANY ACTIVITY THAT DOES OCCUR WILL NOT REDUCE
VISIBILITIES.
BILLINGS
PREV DISCUSSION... /ISSUED 329 AM CST SUN DEC 9 2012/
DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 41 12 37 19 / 10 10 0 0
HUTCHINSON 37 11 37 21 / 10 10 0 0
NEWTON 37 12 35 20 / 10 10 0 0
ELDORADO 40 13 35 18 / 10 10 0 0
WINFIELD-KWLD 42 14 37 21 / 10 10 0 0
RUSSELL 35 4 37 19 / 10 0 0 0
GREAT BEND 34 7 37 22 / 20 0 0 0
SALINA 36 9 37 20 / 10 10 0 0
MCPHERSON 36 11 37 20 / 10 10 0 0
COFFEYVILLE 47 18 36 19 / 20 10 0 0
CHANUTE 44 14 34 18 / 20 10 0 0
IOLA 43 14 34 20 / 20 10 0 0
PARSONS-KPPF 45 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
527 AM CST SUN DEC 9 2012
.AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS LIFR/IFR CONDITIONS AHEAD OF
THE FRONT AND THEN STRONG GUSTY WINDS BEHIND THE FRONT TODAY.
THE COLD FRONT IS THROUGH MUCH OF KANSAS...BUT THE STRONGER WINDS
ARE JUST REACHING KRSL AS OF 11Z. WINDS WILL ONLY CONTINUE TO GET
STRONGER THROUGHOUT THE DAY WITH 20-25 KTS GUSTING TO 30-35
EXPECTED ACROSS ALL TERMINALS TODAY. WINDS WILL DECREASE
SOME...BUT STAY BREEZY OVERNIGHT.
AHEAD OF THE FRONT LIFR AND IFR CONDITIONS DOMINATE UNDER LOW
STRATUS. AS THE DRIER/COOLER AIR MOVES IN BEHIND THE FRONT...LOW
STRATUS IS SCATTERING OUT WITH A MID LEVEL CLOUD DECK OVERHEAD.
HAVE REMAINED PESSIMISTIC WITH THE FORECAST AT SITES THAT ARE
AHEAD OF THE FRONT...KICT/KCNU KEEPING THEM IN LIFR UNTIL THE
EXPECTED FRONTAL PASSAGE...ALTHOUGH IT MAY BE OFF AND ON WITH
RAGGED CEILINGS ACROSS THE AREA. SKIES WILL BEGIN TO CLEAR
OVERNIGHT FROM KRSL TO KICT UNDER HIGH PRESSURE.
WHILE THERE IS STILL A HINT OF SOME PRECIPITATION WITH THIS
SYSTEM...CONFIDENCE IS LOW THAT ANY WILL ACTUALLY REACH THE
GROUND. THERE IS DECENT LIFT IN THE MID-LEVELS...BUT THE LOWEST
8-12 KFT ARE VERY DRY AND WOULD EXPECT ANY PRECIPITATION THAT DOES
FALL TO EVAPORATE. THAT BEING SAID...CANNOT RULE OUT SOME DRIZZLE
AHEAD OF THE FRONT...AND SOME FLURRIES BEHIND THE FRONT. DID LEAVE
MENTION OF FLURRIES OUT OF THE FORECAST AT ALL TERMINALS BECAUSE
OF THIS. ANY ACTIVITY THAT DOES OCCUR WILL NOT REDUCE
VISIBILITIES.
BILLINGS
&&
.PREV DISCUSSION... /ISSUED 329 AM CST SUN DEC 9 2012/
DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 38 13 37 19 / 10 10 0 0
HUTCHINSON 35 11 37 21 / 10 10 0 0
NEWTON 35 12 35 20 / 10 10 0 0
ELDORADO 38 13 35 18 / 10 10 0 0
WINFIELD-KWLD 41 14 37 21 / 10 10 0 0
RUSSELL 33 4 37 19 / 10 0 0 0
GREAT BEND 33 7 37 22 / 20 0 0 0
SALINA 35 10 37 20 / 10 10 0 0
MCPHERSON 34 11 37 20 / 10 10 0 0
COFFEYVILLE 46 20 36 19 / 20 10 0 0
CHANUTE 43 16 34 18 / 20 10 0 0
IOLA 42 16 34 20 / 20 10 0 0
PARSONS-KPPF 44 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
329 AM CST SUN DEC 9 2012
.DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 38 13 37 19 / 10 10 0 0
HUTCHINSON 35 11 37 21 / 10 10 0 0
NEWTON 35 12 35 20 / 10 10 0 0
ELDORADO 38 13 35 18 / 10 10 0 0
WINFIELD-KWLD 41 14 37 21 / 10 10 0 0
RUSSELL 33 4 37 19 / 10 0 0 0
GREAT BEND 33 7 37 22 / 20 0 0 0
SALINA 35 10 37 20 / 10 10 0 0
MCPHERSON 34 11 37 20 / 10 10 0 0
COFFEYVILLE 46 20 36 19 / 20 10 0 0
CHANUTE 43 16 34 18 / 20 10 0 0
IOLA 42 16 34 20 / 20 10 0 0
PARSONS-KPPF 44 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1139 PM CST SAT DEC 8 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 926 PM CST SAT DEC 8 2012/
UPDATE...
LOW CLOUDS AND DRIZZLE HAVE OVERSPREAD MUCH OF CENTRAL AND SOUTH
CENTRAL KS THIS EVENING...AS ISENTROPIC LIFT CONTINUES IN THE
295-300K LAYER. THIS WEAK LIFT HAS LED TO SOME SATURATION IN THE
LOWEST LAYERS OF THE ATMOSPHERE...WITH WIDESPREAD STRATUS BUILDING
DOWN AS THE EVENING PROGRESSES WITH DRIZZLE AND SOME AREAS OF FOG.
THIS DRIZZLE AND FOG WILL BE SHORT LIVED...ESPECIALLY ACROSS CENTRAL
KS...AS A STRONG COLD FRONT PUSHES INTO CENTRAL KS BY AROUND 06Z/SUN
AND KEEPS PUSHING SOUTH ACROSS THE REST OF THE REGION LATE TONIGHT
OR EARLY ON SUN. THIS FRONT WILL SHIFT THE WINDS RAPIDLY AROUND TO
THE NORTH AND BECOME GUSTY AT 20 TO 30 MPH. IT WILL ALSO HELP SCOUR
OUT MOST OF THE LOW LEVEL MOISTURE IS IT PUSHES SOUTH...ENDING THE
DRIZZLE AND FOG AS IT MOVES SOUTH.
AS THIS FRONT APPROACHES...WITH A SHORTWAVE PUSHING ACROSS NEB. LIFT
ASSOCIATED WITH THIS FRONT AND SHORTWAVE COULD LEAD TO SOME LIGHT
RAIN ACROSS CEN KS. COULD SEE THIS LIGHT RAIN CHANCE POSSIBLY TURN
OVER OR MIX WITH SOME LIGHT SNOW...AS COLDER AIR ALOFT MOVES ACROSS
NEB BY EARLY ON SUN. BUT LACK OF DEEP MOISTURE WILL MAINLY LEAD TO
VERY LIGHT PRECIPITATION...WITH MAINLY FLURRIES AS IT TURNS OVER TO
SNOW.
KETCHAM
PREV DISCUSSION... /ISSUED 556 PM CST SAT DEC 8 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST WILL LEAD TO
DETERIORATING FLIGHT CONDITIONS THIS EVENING...AS WIDESPREAD MVFR
CIGS/VSBYS AND AREAS OF IFR CIGS PUSH INTO THE AREA THROUGH THE
EVENING HOURS. BOTH THE NAM/WRF AND GFS NOT HANDLING THIS LOWER
CEILING TREND VERY WELL...WITH THE LATEST RUC40 CLOSER TO REALITY.
EVEN WENT MORE PESSIMISTIC THAN THE RUC ON CEILINGS AND FOG.
A COLD FRONTAL BOUNDARY LOOKS TO ARRIVE AFTER 06Z/SUN ACROSS CENTRAL
KANSAS...AND FURTHER SOUTH ACROSS SOUTH CENTRAL KS AFTER
09-10Z/SUN. THIS WILL LEAD TO CEILINGS BEGINNING TO LIFT WITH
MVFR/VFR CEILINGS FOR THE MORNING HOURS ON SUN. WINDS BEHIND THE
FRONT WILL INCREASE TO 20-30 KTS WITH SOME LIGHT SNOW DEVELOPING
ACROSS PORTIONS OF CENTRAL KANSAS ON SUNDAY. NOT EXPECTING THE LIGHT
SNOW TO RESTRICT VSBYS MUCH...AS THIS WILL BE MAINLY A LIGHT SNOW
EVENT/FLURRY EVENT.
KETCHAM
PREV DISCUSSION... /ISSUED 311 PM CST SAT DEC 8 2012/
DISCUSSION...
MAIN FORECAST CONCERNS ARE PRECIP CHANCES AND TYPE TONIGHT THROUGH
SUN ALONG WITH HOW COLD TO GO FOR SUN-MON.
SYNOPSIS:
STRONG SHORTWAVE IS DIVING OVER THE NORTHERN ROCKIES AND APPROACHING
THE NORTHERN HIGH PLAINS. AT THE SURFACE...TROUGHING EXTENDS FROM SW
SD INTO EASTERN CO. THIS HAS LEFT WARM MOIST FLOW OVER THE SOUTHERN
AND CENTRAL PLAINS WHICH HAS ALLOWED LOW CLOUDS TO MOVE BACK IN
ACROSS MUCH OF THE FORECAST AREA.
TONIGHT-SUN NIGHT:
WITH THE LOW LEVEL WARM MOIST FLOW REMAINING IN PLACE...THINKING
THAT THE LOW CLOUDS WILL MAINTAIN AND WILL LIKELY LOWER A BIT THIS EVENING.
IN ADDITION ALSO FEEL THAT AFTER DARK SOME LIGHT FOG AND DRIZZLE
WILL ACCOMPANY THE LOW CIGS. MID LEVEL LIFT WILL COMMENCE OVER
CENTRAL AND NORTHEAST KS THIS EVENING WHICH SHOULD RESULT IN SOME
LIGHT SHOWERS WITH SOME OF THESE SHOWERS TRANSITIONING TO SOME LIGHT
SNOW AFTER AFTER 3 AM AS MUCH COLDER AIR STARTS TO SPILL-IN FROM THE
NORTH. NOT EXPECTING ANYTHING IN THE WAY OF ACCUMULATION OVERNIGHT.
JUST LIKE THE LAST FEW MODEL RUNS...THE MAIN PIECE OF ENERGY IS
EXPECTED TO BREAK OFF INTO TWO PIECES. ONE WILL MOVE TOWARDS THE
GREAT LAKES WHILE THE OTHER DIVES OVER THE DESERT SW AND EVENTUALLY
THE SOUTHERN PLAINS. STILL THINKING THAT THE PRECIP ON SUN WILL
PRIMARILY BE IN THE FORM OR FLURRIES AND SPRINKLES. THE EXCEPTION
WOULD BE THE EAST AND NORTHEAST FRINGES OF THE FORECAST AREA WHERE
THE DEEPER LIFT AND MOISTURE WILL BE SITUATED. EVEN THE LOCATIONS
THAT DO SEEM SOME SNOW SHOWERS CAN EXPECT TO ONLY PICKUP VERY LIGHT
AMOUNTS. THE MAIN STORY WITH THIS SYSTEM WILL CONTINUE TO BE THE
COLDEST TEMPS OF THE SEASON SO FAR WITH SINGLE DIGITS A GOOD BET FOR
MUCH OF CENTRAL KS MON MORNING.
MON-SAT:
THE LONGWAVE TROUGH IS EXPECTED TO POSITION ITSELF OVER THE CENTRAL
CONUS TO START THE WORK WEEK AS ADDITIONAL UPPER IMPULSES DIVE DOWN
THE BACKSIDE OF THE TROUGH AND ACROSS THE SOUTHERN PLAINS FOR MON
NIGHT INTO TUE. THIS PATTERN WILL RESULT IN A CONTINUATION OF BELOW
NORMAL TEMPS WITH THE MOISTURE AND ASSOCIATED PRECIP CHANCES PUSHED
WELL EAST OF THE FORECAST AREA. BY MID WEEK THE UPPER PATTERN WILL
QUICKLY TRANSITION FROM NW FLOW ALOFT TO SW FLOW BY WED AFTERNOON AS
OUR NEXT SHORTWAVE DIGS OVER THE WEST COAST. THIS WILL GET THE
PLAINS BACK INTO A WARMING PATTERN THAT WILL CONTINUE FOR THU INTO
FRI.
THE SHORTWAVE WILL START TO DIRECTLY IMPACT THE AREA BY FRI INTO
SAT. THE ECMWF IS MUCH MORE COMPACT THE MORE PROGRESSIVE WITH THIS
WAVE COMPARED TO THE GFS. REGARDLESS OF WHICH ONE VERIFIES IT
APPEARS THE BEST SNOW CHANCES WILL BE NORTH OF THE FORECAST AREA
WITH SOME SHOWERS AND EVEN A FEW STORMS POSSIBLE FOR
FRI...TRANSITIONING TO SOME LIGHT SNOW OR FLURRIES FOR FRI NIGHT.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 35 38 13 35 / 10 10 10 0
HUTCHINSON 34 35 12 36 / 10 10 10 0
NEWTON 34 37 12 35 / 10 20 10 0
ELDORADO 36 39 14 34 / 10 20 10 0
WINFIELD-KWLD 37 39 15 36 / 10 20 10 0
RUSSELL 28 32 6 39 / 20 10 10 0
GREAT BEND 31 33 7 38 / 10 10 10 0
SALINA 31 32 10 37 / 20 10 10 0
MCPHERSON 34 35 11 36 / 20 10 10 0
COFFEYVILLE 44 45 19 36 / 10 30 10 10
CHANUTE 42 43 18 34 / 10 30 10 10
IOLA 41 43 17 33 / 10 30 10 10
PARSONS-KPPF 43 44 18 35 / 10 30 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1018 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 757 PM MST SAT DEC 8 2012
PER SATELLITE AND LATEST MODEL DATA INCREASED CLOUD COVER THROUGH
TOMORROW MORNING. LOOKING AT CURRENT SURFACE OBSERVATION DATA AND
CONSIDERING THE HIGHER WINDS/MORE CLOUD COVER...CHOSE TO RAISE
MINS A LITTLE WHICH DOES FIT WITH SOME OF THE NEWER GUIDANCE.
CURRENT PRECIPITATION FORECAST LOOKS FINE. WINDS WILL BEGIN
GUSTING TO JUST UNDER WIND ADVISORY CRITERIA. IT LOOKS CLOSE FOR
WIND ADVISORY AND WILL LET THE OVERNIGHT SHIFT ADDRESS THAT. GRIDS
ARE ALREADY REFLECTING IT.
UPDATE ISSUED AT 605 PM MST SAT DEC 8 2012
JUST COMPLETED AN UPDATE. FIRST FRONT IN A SERIES OF FRONTS
ALREADY BLASTING THROUGH WHICH IS FASTER THAN ANY MODEL DEPICTION
OR WHAT THE GRIDS HAD WHICH IS NOT UNCOMMON IN THIS SCENARIO. NOT
ONLY IS THE FRONT THROUGH...BUT WIND SPEEDS ALREADY TO NEAR 40 MPH
IN SOME LOCATIONS. RUC WAS THE FASTEST MODEL BUT WAS STILL A LITTLE
SLOW AND UNDERDONE ON THE SPEEDS. SO USED IT AND MODIFIED WITH
REALITY. HOPEFULLY NEWER MODEL DATA WILL CATCH UP WITH THIS. ALSO
INCREASED SPEEDS FOR LATER TONIGHT AND TOMORROW AS WELL WITH WHAT
LOOKS TO BE DECENT MIXING. CONSIDERING THE COLD AIR ADVECTION
ALREADY OCCURRING...THERE MAY NOT BE ANY LOW LEVEL INVERSION TO
OVERCOME AND WIND SPEEDS MAY BE EVEN HIGHER THAN WHAT I HAVE
DEPICTED. WILL CONTINUE TO WATCH AND TWEAK AS NEWER DATA COMES IN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1059 AM MST SAT DEC 8 2012
EXCEPT FOR THE COLD AIR MOVING IN BEHIND THE FRONT THIS EVENING
AND OVERNIGHT...THIS EVENT IS BEGINNING TO LOOK MORE LIKE A NON-
EVENT. HAVE TONED DOWN THE MENTION OF ANY ACCUMULATING SNOW AND
HAVE PUT IN A MENTION OF SPRINKLES OR FLURRIES IN THE FAR
NORTHWEST CORNER OF THE FORECAST AREA BEFORE 00Z WITH A MORE
EXTENSIVE AREA OF FLURRIES ALONG AND BEHIND THE FRONT AS IT MOVES
THROUGH THE FORECAST AREA TONIGHT. THE NAM CONTINUES TO BE DRY WITH THE
ECMWF AND GFS ONLY PRODUCING AROUND ONE HUNDREDTH OF QPF ALONG THE
NORTHERN AND WESTERN FRINGES OF THE FORECAST AREA. FLURRIES WILL
DIMINISH EARLY SUNDAY WITH SKIES BEGINNING TO CLEAR BY LATE SUNDAY
AFTERNOON AS SURFACE HIGH PRESSURE BEGINS TO MOVE INTO THE REGION.
BECAUSE OF THE DECREASING CLOUDS COVER AND SLACKENING WINDS SUNDAY
NIGHT...EXPECT THE COLDEST TEMPERATURES OF THE SEASON WITH LOWS
DROPPING DOWN TO AROUND ZERO IN SOME LOCATIONS. WIND CHILL BELOW
ZERO WILL BE COMMON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MST SAT DEC 8 2012
SUNDAY NIGHT THROUGH TUESDAY NIGHT THE BASE OF THE LONG WAVE TROUGH
WILL REMAIN OVER THE AREA.
SUNDAY NIGHT THE TROUGH AXIS...FROM THE SHORT WAVE TROUGH
RESPONSIBLE FOR THE WINTER STORM OVER THE NORTHERN PLAINS...WILL
MOVE THROUGH THE AREA. UNFORTUNATELY DRIER AIR WILL BE OVER THE
AREA BY THE TIME THE TROUGH AXIS MOVES THROUGH AND THE LEFT
ENTRANCE OF THE 500-300MB JET WILL BE OVER THE AREA AHEAD OF THE
TROUGH AXIS...LEADING TO DRY CONDITIONS FOR THE AREA. WINDS WILL
DECREASE DURING THE EVENING AS A SURFACE HIGH BUILDS INTO THE
AREA. WITH LITTLE TO NO WIND AND CLEAR SKIES...TEMPERATURES WILL
FALL TO THE SINGLE DIGITS. ANY WIND THAT DOES DEVELOP WILL PRODUCE
WIND CHILL VALUES NEAR 15 BELOW ZERO.
MONDAY SEVERAL WEAKER SHORT WAVE TROUGHS MOVE THROUGH...BUT THERE
WILL BE LITTLE TO NO MOISTURE TO WORK WITH. DURING THE LATE
AFTERNOON/EVENING AREA SOUNDINGS SATURATE AS MOISTURE MOVES INTO THE
AREA BEHIND A SURFACE AND UPPER LEVEL TROUGH. HOWEVER THE
INCREASED MOISTURE WILL BE IN THE SUBSIDENCE AREA BEHIND THE SHORT
WAVE TROUGH.
FOR THE TUESDAY THROUGH SATURDAY PERIOD...DRY CONDITIONS WILL
CONTINUE TO PREVAIL. THE LONG WAVE TROUGH MOVES EAST TUESDAY
ALLOWING A LONG WAVE RIDGE TO MOVE OVER THE CENTRAL PLAINS THROUGH
THE MAJORITY OF NEXT WEEK. MEANWHILE THE NEXT SHORT WAVE TROUGH
MOVES ONSHORE WEDNESDAY...APPROACHING THE AREA FRIDAY. MODELS AGREE
WITH THE TRACK OF THE TROUGH...MOVING IT OVER THE TEXAS AND OKLAHOMA
PANHANDLES. THE POSITION OF THE TROUGH IS STILL TOO FAR SOUTH FOR
THE AREA TO RECEIVE ANY PRECIPITATION. HOWEVER THE MODELS HAVE
TRENDED FURTHER NORTH WITH THE TROUGH SINCE YESTERDAY. FRIDAY NIGHT
THE GEFS MEMBERS INDICATED A SLIGHT CHANCE FOR SOME PRECIPITATION
OVER THE EASTERN PART OF THE AREA. GFS ISENTROPIC LIFT DOES SHOW
SOME LIFT AND MOISTURE CO-LOCATED AROUND 600MB OVER THOSE
LOCATIONS. IF THIS FEATURE IS STILL THERE TOMORROW...SLIGHT CHANCES
MAY NEED TO BE ADDED FOR THE EAST FRIDAY NIGHT.
TEMPERATURES WILL BE NEAR NORMAL...WITH A SMALL WARMING TREND
THROUGH THE PERIOD. A COLD FRONT WILL MOVE THROUGH FRIDAY BEHIND
THE UPPER LEVEL TROUGH...BUT THE COOLER AIR MASS BEHIND THE FRONT
WILL QUICKLY MOVE EAST FOLLOWING THE UPPER LEVEL TROUGH. THIS WILL
ALLOW TEMPERATURES FOR SATURDAY TO REMAIN LARGELY UNAFFECTED BY THE
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1016 PM MST SAT DEC 8 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SOME LOW CLOUDS
COULD OCCUR BUT ARE EXPECTED TO SCATTERED AND NEAR TO SLIGHTLY
ABOVE MVFR. STRONG AND GUSTY NORTH TO NORTHWEST WILL CONTINUE NEAR
SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
817 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION OVERNIGHT. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT AND CONTINUE ACROSS THE
MIDDLE ATLANTIC THROUGH THE END OF THE WEEK. &&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS SHOWS THE COLD FRONT CURRENTLY PUSHING EAST OF THE
BLUE RIDGE MOUNTAINS...WITH PATCHY RAIN ALONG AND BEHIND THE
BOUNDARY. BELIEVE THE PRECIP SHOWING UP ACROSS WESTERN MARYLAND IS
ASSOCIATED WITH THE FRONT.
PATCHY PRECIP WILL CONTINUE THROUGH THE EVENING...WITH ONLY LIGHT
QPF. HAVE TRIED TO ORIENT POPS ACCORDING TO RADAR TRENDS...BUT WILL
LIKELY HAVE TO DO ADDITIONAL TWEAKS AS THE FRONT MOVES EAST OF THE
BLUE RIDGE MOUNTAINS INTO THE METRO AREAS.
PRETTY GOOD WIND SHIFT/GUSTS IMMEDIATELY BEHIND THE FRONT...SO ANY
LINGERING FOG SHOULD DISSIPATE AFTER THE FROPA. SOME SLIGHT CLEARING
IS POSSIBLE TOWARDS SUNRISE...BUT SKIES SHOULD REMAIN PARTLY/MOSTLY
CLOUDY OVERNIGHT.
IN THE WESTERN UPSLOPE REGION...SNOW SHOWERS ARE LIKELY STARTING
AROUND MIDNIGHT AND LASTING UNTIL MID TUE MORNING. SNOW ACCUM
SHOULD BE AROUND ONE INCH WELL UNDER SNOW ADVSRY LEVELS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH 6 PM TUESDAY/...
THE FRONT HANGS UP A BIT IN THE EARLY MORNING IN THE
SOUTHEASTERNMOST PORTION OF OUR CWA...WHICH WILL CAUSE CLOUDS TO
LINGER BUT I BELIEVE THAT THE SHRA WILL BE EAST OF THE MD PORTION
OF THE BAY BY DAYBREAK.
ELSEWHERE...A SUNNY START BEFORE HIGH CLOUDS WORK INTO THE REGION
BY MIDDAY AS INDICATED BY RH 80% OR HIGHER AOA H4 STREAMING FROM
THE GULF OF MEXICO AND ALSO BEING IN THE RR QUAD OF UPPER LEVEL
JET. AREAS W OF I-81 WILL BE ON THE WESTERN FRINGE OF THESE HIGH
CLOUDS...AND MAY EVEN EXPERIENCE PRETTY MUCH MOSTLY SUNNY SKIES
ALL DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
SURFACE HIGH PRESSURE SETTLES OVER THE MID-ATLANTIC TUESDAY NIGHT
THROUGH THURSDAY. AN UPPER LEVEL DISTURBANCE EJECTS FROM THE THE
GULF STATES WEDNESDAY MORNING AND APPROACHES THE MID-ATLANTIC
WEDNESDAY NIGHT INTO THURSDAY. THE SYSTEM PASSES BY TO OUR SOUTH AS
SURFACE LOW PRESSURE IS SPAWNED UP OFF THE NORTH CAROLINA COAST
THURSDAY MORNING. THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS
IDEA. THE 12Z GFS HAS A FRONT EVEN A BIT FARTHER SOUTH THURSDAY
MORNING...KEEPING ANY PRECIPITATION OUT OF FAR SOUTHERN MARYLAND
THOUGH THERE WILL BE SOME CLOUD COVER FROM THIS. THE FLOW WILL BE LIGHT
OUT OF THE NORTH WEDNESDAY FOR COOLER AND DRIER AIR. THE NAM HAS
BACKED AWAY FROM AN EARLIER SUGGESTION OF AN EASTERLY FLOW WEDNESDAY
NIGHT AND THURSDAY. THURSDAY COULD SEE MORE SUNSHINE WITH A LITTLE
MILDER TEMPERATURES.
UPPER LOW PRESSURE OVER THE WESTERN STATES SPLITS AS A NORTHERN
BRANCH SYSTEM SWEEPS INTO THE PLAIN STATES SATURDAY MORNING. THIS
SYSTEM MAY PROGRESS INTO THE NORTHEAST STATES BY SUNDAY. FRIDAY
LOOKS DRY AND MILD WITH A LIGHT FLOW ALOFT AND PLENTY OF SUNSHINE.
CLOUDS MAY INCREASE SATURDAY AS THE WAVE APPROACHES. THE GFS SPREADS
SHOWERS INTO THE WESTERN MOUNTAINS BY AFTERNOON. GFS HAS THE SURFACE
LOW OVER OHIO SUNDAY MORNING WHILE THE EC HAS IT A BIT FARTHER
NORTH. THE EC DEVELOPS A 991MB LOW RIGHT OVER CENTRAL VA SUNDAY
NIGHT AND LIFTS IT UP THE COAST WHILE THE GFS BOMBS IT OUT WELL
OFFSHORE. THE DIFFERENCE IS A MUCH MORE AMPLIFIED JET BETWEEN THE
RIDGE OVER THE ATLANTIC AND THE WAVE. IN EITHER EVENT WE HAVE
INTRODUCED SHOWERS ACROSS THE AREA SATURDAY NIGHT AND CONTINUED
THEM INTI MONDAY FOR THE TIME BEING.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
MRB AND MTN ARE CURRENTLY LIFR/VLIFR RESPECTIVELY. FRONT IS RIGHT
ON TOP OF KMRB...AND DO EXPECT IMPROVING CONDITIONS AS THE WINDS
PICK UP OUT OF THE NW BEHIND THE FRONTAL PASSAGE. MTN SHOULD STAY
DOWN A ONE OR TWO MORE HOURS...UNTIL AFTER THE FROPA.
AT THE REMAINDER OF THE TERMINAL SITES...CIGS/VSBYS REMAIN VFR. DO
EXPECT SOME LOWERING OF CIGS/VSBYS TO MVFR AS THE FRONT MOVES
OVERHEAD. WINDS WILL SHIFT TO THE NW BEHIND THE FRONT...AND REMAIN
AROUND 10 KT OVERNIGHT WHICH SHOULD LIMIT THE DEVELOPMENT OF FOG.
VFR CONDITIONS EXPECTED ON TUESDAY.
VFR CONDITIONS ARE LIKELY TO PERSIST AS SURFACE HIGH PRESSURE BUILDS
IN TUESDAY NIGHT INTO FRIDAY. A MID LEVEL OVC WILL MOVE OVERHEAD
WEDNESDAY AS A WAVE MOVES BY TO THE SOUTH. BREEZY NORTH WINDS TO 15
KTS ARE POSSIBLE WEDNESDAY...SHIFTING TO THE NE WEDNESDAY NIGHT. A
SOUTHWEST FLOW ALOFT WILL INCREASE FRIDAY AS A WEATHER SYSTEM
APPROACHES FROM THE OHIO VALLEY.
&&
.MARINE...
A COLD FRONT WILL CROSS THE WATERS OVERNIGHT. WINDS ARE CURRENTLY
OUT OF THE S/SW. AFTER THE FRONT WINDS WILL SHIFT TO THE NW AND
GUSTS TO AROUND 20 KT DURING THE REMAINDER OF THE INTO TUESDAY.
WINDS SHOULD DIMINISH BELOW CRITERIA TUESDAY AFTERNOON.
SURFACE HIGH PRESSURE BUILDS OVER THE WATERS IN TUESDAY NIGHT INTO
FRIDAY. BREEZY NORTH WINDS MAY APPROACH SCA CRITERIA WEDNESDAY AS A
WEATHER DISTURBANCE PASSES BY TO THE SOUTH. LIGHT WINDS AND FAIR
WEATHER ARE ANTICIPATED THURSDAY AND FRIDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TUESDAY FOR ANZ530-531-535-
536-538-539.
SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR ANZ532>534-537-
540>543.
&&
$$
UPDATE...LISTEMAA
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
546 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
EVENING AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO MOVE ACROSS THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A BRIEF INTERLUDE SEEMS LIKELY TO ENSUE BETWEEN THE MAINLY PRE-
WARM FRONTAL ISENTROPIC STRATIFORM PRECIPITATION AND THE WARM
SECTOR CONVECTIVE PRECIPITATION THIS EVENING FOR MANY SECTIONS OF
THE FORECAST AREA. HOWEVER...WITH THE NORTHWARD MIGRATION OF THE
WARM FRONT...MID-LEVEL INSTABILITY DOES INCREASE ALL THE WHILE
SYNOPTIC FORCING VIA UPPER DIVERGENCE FROM A NEARING AND SLIGHTLY
ANTI-CYCLONICALLY CURVED RIGHT ENTRANCE OF AN UPPER JET STREAK
COMES INTO PLAY. THE CURVATURE OF THIS JET STREAK SHOULD HELP TO
GIVE ADDITIONAL AGEOSTROPHIC ENHANCEMENT OF UPPER DIVERGENCE
FIELD AND THEREBY YIELD MORE STRONGLY NEGATIVE OMEGAS. THIS
COUPLED WITH THE DOWNFLOW TRAJECTORY OF MID-LEVEL FORCING VIA
IMPRESSIVE FRONTOGENESIS AND DIFFERENTIAL PVA AS WELL AS A FAIRLY
LOW PENETRATING PV ANOMALY ON THE MODEL CONSENSUS THAT TRACKS A
WEAK TROPOPAUSE FOLD FROM MISSOURI INTO NORTHERN OHIO THROUGH
MONDAY WOULD FAVOR A SWATH OF HEAVIER RAINFALL JUST AHEAD OF SAID
CORRIDOR. THIS WEAK FOLD IS LIKELY RESPONSIBLE FOR THE STRONG MID-
LEVEL FRONTOGENESIS NOTED ON THE MODELS.
GIVEN SAID SETUP...QPF GRIDS WERE INCREASED PRIMARILY FROM
ZANESVILLE TO MERCER COUNTY OR SO. THE MODEL CONSENSUS FAVORS THIS
FARTHER WEST QPF AXIS...WHILE THE GFS PREFERS A FARTHER EAST
PLACEMENT. HOWEVER...GIVEN THE TRACK OF THE UPPER LEVEL
FIELDS...THE GFS POSITIONING FAILS THE SANITY TEST AT THIS TIME.
OTHER THAN MAINLY QPF AND SLIGHT POP ADJUSTMENTS THIS
EVENING...THE REST OF THE FORECAST FEATURES STEADY/RISING
TEMPERATURES WITH THE NORTHWARD SLOSH OF THE WARM FRONT STILL
SEEMS ON TRACK. FRIES
PREVIOUS DISCUSSION FOLLOWS...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND
IT. A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW
ACROSS SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE
IS RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS EVENING...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IS CURRENTLY
MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM FRONT
AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF THIS
FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND THUS
POPS INCREASE TO CATEGORICAL.
TEMPS WILL BE SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM WITH A WARM
SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER 21Z.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. ITS WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH
WILL BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS
AND SHOWERS AHEAD OF THE COLD FRONT MOVING IN FROM THE
WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF THE
OVERNIGHT. TEMPS WILL REMAIN INCREASE A FEW DEGREES OVERNIGHT IN
WAA...WITH LOWS RANGING FROM THE MID 50S IN NORTH- CENTRAL WV TO
THE LOWER 30S NORTH OF THE I-80 CORRIDOR.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL
DE-AMPLIFY AS IS SLIDES EASTWARD ACROSS THE GREAT LAKES AND PUSHES A
COLD FRONT ACROSS THE UPPER OHIO VALLEY ON MONDAY. A MODEL CONSENSUS
OF THE EQUIVALENT POTENTIAL TEMPERATURE GRADIENT INDICATES A COLD
FRONT JUST NORTHWEST OF THE PITTSBURGH METRO AROUND 18Z ON MONDAY.
AHEAD OF THE FRONT...H5 VORTICITY INDICATES ENERGY IN WAA THAT WILL
ALLOW FOR SCATTERED SHOWERS AHEAD OF THE FRONT. A WELL-DEFINED
SURFACE TROUGH ASSOCIATED WITH THE COLD FRONT ALONG WITH THE STRONG
THERMAL GRADIENT ALONG THE FRONT WILL ALSO PROVIDE SUFFICIENT
FORCING FOR SHOWERS ALONG AND BEHIND THE FRONT. WITH THIS IN
MIND...CATEGORICAL POPS ARE FORECAST ACROSS THE MAJORITY OF THE AREA
THROUGH 21Z. WITH THE STRENGTH OF THE FRONT...VERY WEAK
INSTABILITY...AND STRONG SHEAR IN PLACE...HAVE INCLUDED A SCHC
THUNDER MENTION LATE MONDAY MORNING INTO THE EARLY AFTERNOON.
AHEAD OF THE FRONT...ONGOING WAA WILL ALLOW TEMPS TO BE IN THE UPPER
50S ACROSS MANY LOCATIONS WITH EVEN TEMPS NEAR 60 POSSIBLE IN
NORTH-CENTRAL WV.
CAA WILL ENSUE ACROSS THE ENTIRE AREA BY 00Z TUESDAY AS THE FRONT
SHIFTS SOUTHEAST OF THE AREA. WITH STRONG CAA...850MB TEMPS WILL
COOL TO AROUND 6-8C BY 12Z TUESDAY. 1000-500MB THICKNESS LINE DROPS
SOUTHEASTWARD QUICKLY OVERNIGHT AND IN RETURN...ANY LINGERING RAIN
SHOWERS WILL TURN TO SNOW SHOWERS BEHIND THE FRONT. SNOW
ACCUMULATION WILL BE LIGHT...WITH A DUSTING IN MOST LOWLAND
LOCATIONS AND UP TO AN INCH POSSIBLE ACROSS THE EASTERN RIDGES. LOWS
ON MONDAY NIGHT WILL ARE NOT FAR FROM A MAV/MET BLEND...IN THE UPPER
20S TO LOWER 30S ACROSS THE AREA.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM
THE SOUTHWEST ON TUESDAY. A COLD WEST-NORTHWESTERLY 850MB FLOW WILL
ALLOW FOR THE CHANCE OF SNOW SHOWERS TO LINGER INTO THE EARLY
AFTERNOON FOR LOCATIONS NORTH AND EAST OF PITTSBURGH. 850MB FLOW
THEN BACKS TO MORE SOUTHWESTERLY AND WILL ALLOW FOR DECREASING CLOUD
COVERAGE TUESDAY NIGHT. AS THE HIGH MOVES OVER THE AREA ON
WEDNESDAY...MORE ABUNDANT SUNSHINE IS ANTICIPATED. WITH THE CORE OF
THE COOLEST AIR ACROSS THE AREA ON TUESDAY...HIGHS WILL BE AROUND A
FEW DEGREES BELOW NORMAL...STRUGGLING TO REACH 40. CLEARING SKIES
TUESDAY NIGHT WILL ALLOW FOR SOME RADIATIONAL COOLING...WITH LOWS IN
THE LOW TO MID 20S ACROSS THE AREA. MORE SUNSHINE WEDNESDAY WILL
CONTRIBUTE TO HIGHS NEAR SEASONAL VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A QUIET START TO THE LONG RANGE WITH A SURFACE RIDGE
AXIS EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY
DOMINATING THROUGH FRIDAY NIGHT. THIS WILL BRING DRY AND A BIT ABOVE
AVERAGE TEMPERATURES.
BY LATER SATURDAY A DEVELOPING STORM SYSTEM ACROSS THE CENTRAL
PLAINS WILL BEGIN TO SPREAD MOISTURE ACROSS THE OHIO VALLEY WITH
SHOWERS INCREASING AND CONTINUING SUNDAY AS LOW PRESSURE HEADS TO
THE WESTERN GREAT LAKES. ALL RAIN EXPECTED WITH THIS SYSTEM WITH
TEMPERATURES WELL ABOVE NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW INTO EASTERN OHIO WILL SPREAD ACROSS
REMAINDER OF TERMINALS THIS AFTERNOON. CIGS WILL LOWER TO IFR AFTER
A FEW HOURS OF RAIN BY THIS EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH FRIDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY NIGHT THROUGH FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
301 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
EVENING AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO MOVE ACROSS THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND IT.
A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW ACROSS
SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS EVENING...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IS CURRENTLY
MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM FRONT
AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF THIS
FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND THUS
POPS INCREASE TO CATEGORICAL.
TEMPS WILL BE SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM WITH A WARM
SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER 21Z.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. ITS WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH
WILL BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS
AND SHOWERS AHEAD OF THE COLD FRONT MOVING IN FROM THE
WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF THE
OVERNIGHT. TEMPS WILL REMAIN INCREASE A FEW DEGREES OVERNIGHT IN
WAA...WITH LOWS RANGING FROM THE MID 50S IN NORTH- CENTRAL WV TO
THE LOWER 30S NORTH OF THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL
DE-AMPLIFY AS IS SLIDES EASTWARD ACROSS THE GREAT LAKES AND PUSHES A
COLD FRONT ACROSS THE UPPER OHIO VALLEY ON MONDAY. A MODEL CONSENSUS
OF THE EQUIVALENT POTENTIAL TEMPERATURE GRADIENT INDICATES A COLD
FRONT JUST NORTHWEST OF THE PITTSBURGH METRO AROUND 18Z ON MONDAY.
AHEAD OF THE FRONT...H5 VORTICITY INDICATES ENERGY IN WAA THAT WILL
ALLOW FOR SCATTERED SHOWERS AHEAD OF THE FRONT. A WELL-DEFINED
SURFACE TROUGH ASSOCIATED WITH THE COLD FRONT ALONG WITH THE STRONG
THERMAL GRADIENT ALONG THE FRONT WILL ALSO PROVIDE SUFFICIENT
FORCING FOR SHOWERS ALONG AND BEHIND THE FRONT. WITH THIS IN
MIND...CATEGORICAL POPS ARE FORECAST ACROSS THE MAJORITY OF THE AREA
THROUGH 21Z. WITH THE STRENGTH OF THE FRONT...VERY WEAK
INSTABILITY...AND STRONG SHEAR IN PLACE...HAVE INCLUDED A SCHC
THUNDER MENTION LATE MONDAY MORNING INTO THE EARLY AFTERNOON.
AHEAD OF THE FRONT...ONGOING WAA WILL ALLOW TEMPS TO BE IN THE UPPER
50S ACROSS MANY LOCATIONS WITH EVEN TEMPS NEAR 60 POSSIBLE IN
NORTH-CENTRAL WV.
CAA WILL ENSUE ACROSS THE ENTIRE AREA BY 00Z TUESDAY AS THE FRONT
SHIFTS SOUTHEAST OF THE AREA. WITH STRONG CAA...850MB TEMPS WILL
COOL TO AROUND 6-8C BY 12Z TUESDAY. 1000-500MB THICKNESS LINE DROPS
SOUTHEASTWARD QUICKLY OVERNIGHT AND IN RETURN...ANY LINGERING RAIN
SHOWERS WILL TURN TO SNOW SHOWERS BEHIND THE FRONT. SNOW
ACCUMULATION WILL BE LIGHT...WITH A DUSTING IN MOST LOWLAND
LOCATIONS AND UP TO AN INCH POSSIBLE ACROSS THE EASTERN RIDGES. LOWS
ON MONDAY NIGHT WILL ARE NOT FAR FROM A MAV/MET BLEND...IN THE UPPER
20S TO LOWER 30S ACROSS THE AREA.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM
THE SOUTHWEST ON TUESDAY. A COLD WEST-NORTHWESTERLY 850MB FLOW WILL
ALLOW FOR THE CHANCE OF SNOW SHOWERS TO LINGER INTO THE EARLY
AFTERNOON FOR LOCATIONS NORTH AND EAST OF PITTSBURGH. 850MB FLOW
THEN BACKS TO MORE SOUTHWESTERLY AND WILL ALLOW FOR DECREASING CLOUD
COVERAGE TUESDAY NIGHT. AS THE HIGH MOVES OVER THE AREA ON
WEDNESDAY...MORE ABUNDANT SUNSHINE IS ANTICIPATED. WITH THE CORE OF
THE COOLEST AIR ACROSS THE AREA ON TUESDAY...HIGHS WILL BE AROUND A
FEW DEGREES BELOW NORMAL...STRUGGLING TO REACH 40. CLEARING SKIES
TUESDAY NIGHT WILL ALLOW FOR SOME RADIATIONAL COOLING...WITH LOWS IN
THE LOW TO MID 20S ACROSS THE AREA. MORE SUNSHINE WEDNESDAY WILL
CONTRIBUTE TO HIGHS NEAR SEASONAL VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A QUIET START TO THE LONG RANGE WITH A SURFACE RIDGE
AXIS EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY
DOMINATING THROUGH FRIDAY NIGHT. THIS WILL BRING DRY AND A BIT ABOVE
AVERAGE TEMPERATURES.
BY LATER SATURDAY A DEVELOPING STORM SYSTEM ACROSS THE CENTRAL
PLAINS WILL BEGIN TO SPREAD MOISTURE ACROSS THE OHIO VALLEY WITH
SHOWERS INCREASING AND CONTINUING SUNDAY AS LOW PRESSURE HEADS TO
THE WESTERN GREAT LAKES. ALL RAIN EXPECTED WITH THIS SYSTEM WITH
TEMPERATURES WELL ABOVE NORMAL.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW INTO EASTERN OHIO WILL SPREAD ACROSS
REMAINDER OF TERMINALS THIS AFTERNOON. CIGS WILL LOWER TO IFR AFTER
A FEW HOURS OF RAIN BY THIS EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH FRIDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY NIGHT THROUGH FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
116 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
AFTERNOON AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO RETURN TO THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO ACCOUNT FOR
THE LATEST POSITION OF THE NEXT WAVE OF SHOWERS MOVING INTO THE
AREA.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND IT.
A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW ACROSS
SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS AFTERNOON...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IN
CURRENTLY MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM
FRONT AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF
THIS FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND
THUS POPS INCREASE TO CATEGORICAL BY 00Z.
RAP/NAM MODEL SOUNDINGS AT KZZV INDICATE SOME NARROW CAPE
DEVELOPING (LESS THAN 200 J/KG) AFTER 21Z. WITH THE WARM FRONT
LIFTING INTO THE AREA AND TDS SURGING INTO THE LOWER TO MID
50S...HAVE ADDED THE SCHC OF THUNDER THIS AFTERNOON INTO THE
EVENING FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
TEMPS TODAY WILL SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM MUCH OF THE
DAY WITH THE WARM SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER
21Z. THUS...WITH THE FRONT PUSHING INTO THE AREA...QUITE A THERMAL
GRADIENT CAN BE EXPECTED FOR HIGHS TODAY THAT WILL RANGE FROM THE
LOWER 40S IN JEFFERSON/FOREST COUNTIES TO THE LOWER 60S IN
PORTIONS OF NORTH-CENTRAL WV AND EASTERN OHIO.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. THE WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH WILL
BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS AND
SCHC THUNDER INITIALLY AND SHOWERS AHEAD OF THE COLD FRONT MOVING
IN FROM THE WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF
THE OVERNIGHT. TEMPS WILL DROP OFF LITTLE OVERNIGHT IN WAA...WITH
LOWS RANGING FROM THE MID 50S IN NORTH-CENTRAL WV TO THE MID 40S
ALONG THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE SURFACE TROUGH AND COLD FRONT WILL CROSS THE AREA THROUGH THE
EARLY PART OF THE DAY...WITH CATEGORICAL POPS. TEMPERATURES WILL
REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S TO MID 50S INTO
MIDDAY MONDAY. STRONG CAA WILL THEN BEGIN BEHIND THE FRONT...AS
THE AFOREMENTIONED ARCTIC AIR MASS BEGINS TO PUSH IN FROM THE
WEST. BEFORE RAIN COMES TO AN END OR CHANGES TO SNOW...CONCUR WITH
HPC THAT RAINFALL AMOUNTS FOR SUNDAY INTO MONDAY WILL BE ON THE
ORDER OF 1.0 TO 1.3 INCHES.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT WILL TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL WILL REMAIN
ACROSS THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW MOVING INTO EASTERN OHIO AND WILL BE
INTO KZZV AFTER 18Z AND SPREAD ACROSS REMAINDER OF TERMINALS THIS
AFTERNOON. CIGS WILL LOWER TO IFR AFTER A FEW HOURS OF RAIN BY THIS
EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1044 AM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY TODAY AND
LIFT A WARM FRONT IN THE REGION. THIS WILL ALLOW FOR SHOWERS TO
RETURN TO THE AREA AND CONTINUE INTO MONDAY. A COLD FRONT WILL
CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER TO SNOW
SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING INTO THE
AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADJUST
POPS TODAY TO ACCOUNT FOR THE NEXT WAVE OF SHOWERS. IN
ADDITION...THUNDER MENTION HAS BEEN ADDED FOR THIS AFTERNOON INTO
EARLY TONIGHT FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A SHORT WAVE TROUGH
MOVING FROM THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE
UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS
FEATURE. AT THE SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE
MOVING INTO THE UPPER MIDWEST AND ANOTHER INTO THE MISSOURI
VALLEY. THE FRONTAL BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION
BETWEEN A WARM AND MOIST AIR MASS AHEAD AND ARCTIC AIR BUILDING IN
BEHIND IT. A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN
LOW ACROSS KENTUCKY AND INTO SOUTHERN WV. LOCALLY...THE FIRST
SHORT WAVE IS SHIFTING EAST OF THE RIDGES WHILE THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING ACROSS
EASTERN KENTUCKY.
THIS AFTERNOON...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS AND EMBEDDED ISOLATED THUNDERSTORMS
ASSOCIATED WITH THE SHORT WAVE IN KENTUCKY WILL SLIDE
NORTHEASTWARD WITH THE WARM FRONT INTO THE UPPER OHIO VALLEY EARLY
THIS AFTERNOON. MESOSCALE MODELS ARE SUPPORTIVE OF THIS FEATURE
MOVING THROUGH PART OF THE AREA BY LATE EVENING...AND THUS POPS
INCREASE TO CATEGORICAL BY 00Z.
RAP/NAM MODEL SOUNDINGS AT KZZV INDICATE SOME NARROW CAPE
DEVELOPING (LESS THAN 200 J/KG) AFTER 21Z. WITH THE WARM FRONT
LIFTING INTO THE AREA AND TDS SURGING INTO THE LOWER TO MID
50S...HAVE ADDED THE SCHC OF THUNDER THIS AFTERNOON INTO THE
EVENING FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
TEMPS TODAY WILL SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM MUCH OF THE
DAY WITH THE WARM SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER
21Z. THUS...WITH THE FRONT PUSHING INTO THE AREA...QUITE A THERMAL
GRADIENT CAN BE EXPECTED FOR HIGHS TODAY THAT WILL RANGE FROM THE
LOWER 40S IN JEFFERSON/FOREST COUNTIES TO THE LOWER 60S IN
PORTIONS OF NORTH-CENTRAL WV AND EASTERN OHIO.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. THE WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH WILL
BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS AND
SCHC THUNDER INITIALLY AND SHOWERS AHEAD OF THE COLD FRONT MOVING
IN FROM THE WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF
THE OVERNIGHT. TEMPS WILL DROP OFF LITTLE OVERNIGHT IN WAA...WITH
LOWS RANGING FROM THE MID 50S IN NORTH-CENTRAL WV TO THE MID 40S
ALONG THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE SURFACE TROUGH AND COLD FRONT WILL CROSS THE AREA THROUGH THE
EARLY PART OF THE DAY...WITH CATEGORICAL POPS. TEMPERATURES WILL
REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S TO MID 50S INTO
MIDDAY MONDAY. STRONG CAA WILL THEN BEGIN BEHIND THE FRONT...AS
THE AFOREMENTIONED ARCTIC AIR MASS BEGINS TO PUSH IN FROM THE
WEST. BEFORE RAIN COMES TO AN END OR CHANGES TO SNOW...CONCUR WITH
HPC THAT RAINFALL AMOUNTS FOR SUNDAY INTO MONDAY WILL BE ON THE
ORDER OF 1.0 TO 1.3 INCHES.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT WILL TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL WILL REMAIN
ACROSS THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LOWER CLOUDS HAVE DEPARTED ACROSS THE NORTHERN TERMINALS AT LEAST
FOR A TIME WITH VFR MID DECKS AT KFKL AND KDUJ. ELSEWHERE IFR AT
TIMES CONTINUES AT KMGW WHILE LOW MVFR REMAINS ELSEWHERE.
WARM FRONT EXPECTED TO PUSH NORTH LATER THIS AFTERNOON AND SHOULD
BRING CIGS DOWN AS THE AFTERNOON PROGRESSES WITH RAIN DEVELOPING AT
ALL SITES. CIGS WILL LOWER TO IFR AFTER A FEW HOURS OF RAIN THIS
EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...RSMITH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
611 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER
OHIO VALLEY MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
HAVE ADDED MENTION OF DENSE FOG ACROSS THE HIGHER ELEVATIONS OF
TUCKER COUNTY WV AND GARRETT COUNTY MD...BASED ON RECENT SURFACE
DATA. FOG SHOULD CONTINUE INTO MID MORNING WHEN FIRST BOUT OF RAIN
LESSENS.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH THE MORNING AND MUCH OF THE
AFTERNOON. THE EXCEPTIONS TO THIS WILL BE FKL/DUJ...WHERE LOW
CLOUDS HAVE SCATTERED OUT RESULTING IN VFR CONDITIONS...AND
MGW...WHERE MORNING SHOWERS ARE EXPECTED TO CAUSE IFR CEILINGS.
WITH WARM FRONT EXPECTED TO ARRIVE A BIT LATER IN THE DAY...HAVE
DELAYED MENTION OF RAIN AT ALL SITES EXCEPT MGW UNTIL THE
AFTERNOON HOURS. CEILINGS WILL LOWER TO IFR AFTER A FEW HOURS OF
RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
456 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER OHIO
VALLEY...MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
HAVE ADDED MENTION OF DENSE FOG ACROSS THE HIGHER ELEVATIONS OF
TUCKER WV COUNTY AND GARRETT CO MD COUNTY...BASED ON RECENT
SURFACE DATA. FOG SHOULD CONTINUE INTO MID MORNING WHEN FIRST BOUT
OF RAIN LESSENS.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH MUCH OF THE DAY. ALTHOUGH CURRENT
TAFS DEPICT RAIN BEGINNING TO AFFECT TERMINALS BY NOON...INCOMING
MODEL RUNS SUGGEST THAT IT MAY TAKE LONGER FOR SHOWERS ASSOCIATED
WITH A WARM FRONT TO MOVE INTO THE AREA. CEILINGS WILL LOWER TO
IFR AFTER A FEW HOURS OF RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
420 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER OHIO
VALLEY...MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH MUCH OF THE DAY. ALTHOUGH CURRENT
TAFS DEPICT RAIN BEGINNING TO AFFECT TERMINALS BY NOON...INCOMING
MODEL RUNS SUGGEST THAT IT MAY TAKE LONGER FOR SHOWERS ASSOCIATED
WITH A WARM FRONT TO MOVE INTO THE AREA. CEILINGS WILL LOWER TO
IFR AFTER A FEW HOURS OF RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
117 AM EST SUN DEC 9 2012
.SYNOPSIS...
A NORTHEASTBOUND LOW PRESSURE SYSTEM FROM ARKANSAS WILL BRING MILD
TEMPERATURES AND BOUTS OF RAIN TO THE UPPER OHIO VALLEY INTO
MONDAY...THEN A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
HAVE FORECASTED A SLIGHTLY SLOWER NORTHWARD SPREAD OF RAIN ACROSS
THE UPPER OHIO VALLEY TODAY...BASED ON BLEND OF RECENT SREF MODEL
OUTPUT WITH DETAILS FROM RECENT RAP WRF-NMM AND NAM MODEL RUNS.
TEMPERATURES WILL CONTINUE MILD WITH NEAR STEADY TEMPERATURES
OVERNIGHT AND HIGHS SUNDAY AFTERNOON ABOUT 15 DEGREES WARMER THAN
NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
EXPECT WIDESPREAD RAIN TO CONTINUE SUNDAY NIGHT INTO MONDAY AS
FRONT GRADUALLY CROSSES REGION AS MAIN SURFACE LOW MOVES TO NEW
ENGLAND AND UPPER TROUGH SLOWLY SHIFTS EAST.
RAIN WILL BEGIN TO SHIFT SOUTHEAST WITH FRONT LATE DAY MONDAY AND
AS COLDER AIR WORKS IN SOME CHANGE OVER TO SNOW SHOWERS WILL OCCUR
MONDAY NIGHT.
TOTAL RAINFALL FOR THE EVENT WILL BE AROUND AN INCH
BUT WILL BE SPREAD OVER A 24 TO 36 HOUR PERIOD SO NO FLOOD
PROBLEMS EXPECTED.
SCATTERED SNOW SHOWERS MONDAY NIGHT INTO TUESDAY WILL NOT AMOUNT
TO MUCH AS DEEP MOISTURE WILL HAVE BEEN SHUNTED WELL EAST. FLOW
OFF THE LAKES WILL BE WEAK MONDAY NIGHT AND TUESDAY DESPITE 85OMB
TEMPS REACHING -9C ACROSS THE LAKES BY 12Z TUESDAY.
QUITE MILD SUNDAY NIGHT AHEAD OF THE FRONT THEN A GRADUAL FALL
WITH FROPA MONDAY. BACK TO NEAR NORMAL FOR MONDAY NIGHT AND TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GFS/ECMWF/CANADIAN ARE IN AGREEMENT THAT A SURFACE HIGH WILL BUILD
IN FROM THE SOUTHWEST TUESDAY NIGHT INTO WEDNESDAY AND BECOME
CENTERED OVER THE UPPER OHIO VALLEY BY AROUND 00Z THURSDAY. THERE
ARE SOME MODEL INCONSISTENCIES IN THE PASSAGE OF AN UPPER
TROUGH...HOWEVER SUBSIDENCE AND DRY AIR IN THE LOWER LEVEL WILL KEEP
THE FORECAST DRY REGARDLESS OF ITS TIMING. THUS...A DRY FORECAST IS
IN PLACE THROUGH FRIDAY.
ECMWF/GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP ACROSS THE
CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT LAKES REGION
BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS RETURN TO THE AREA.
MODEL PREDICTABILITY A WEEK OUT MAKES IT DIFFICULT TO PIN DOWN
SPECIFICS IN FRONTAL PLACEMENT...HOWEVER THIS PATTERN FAVORS THE
POTENTIAL FOR OVERRUNNING ALONG WITH WARM FRONTAL RAIN SHOWERS WELL
AHEAD OF THE LOW.
TEMPERATURES WILL BE NEAR SEASONAL NORMALS ON WEDNESDAY WITH THE
POST-FRONTAL CANADIAN AIR MASS STILL IN PLACE BEHIND THE FRONT AND
SOME INCREASED CLOUDINESS FROM THE PASSING MID-LEVEL TROUGH. THE
MID-LEVEL FLOW WILL BECOME MORE SOUTHWESTERLY THURSDAY THROUGH
SATURDAY...ALLOWING FOR TEMPS TO BE AROUND 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SFC ANALYSIS SHOWING A COLD FRONT FROM SW PA INTO NRN WV. THE
FRONT WL CONTINUE TO DRIFT SWD TONIGHT. EXPECTING MVFR NR THE
FRONT...WITH A BRIEF PD OF VFR BEHIND THE FRONT. MVFR...AND EVEN
SOME IFR AT THE NRN TAF SITES...WL THEN RETURN AND PERSIST MUCH OF
THE NIGHT.
THE FRONT STARTS TO RETURN N AS A WARM FRONT ERLY SUN
MRNG. THIS WL SPREAD RAIN INTO THE SRN TAF SITES. MOST OF THE RAIN
ELSEWHERE SHOULD MOVE IN DURING THE MID-LATE AFTN SUN WITH LOW
END MVFR. EXPECTING GRADUALLY VEERING WINDS THROUGH THE PD.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN SUNDAY NIGHT
INTO MONDAY AS A COLD FRONT MOVES THROUGH. MVFR CONDS AND A FEW
SNOW SHOWERS ARE PSBL MONDAY NIGHT INTO ERLY TUE. HIGH PRES AND
VFR CONDS ARE EXPECTED LATER TUE THROUGH THU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
957 AM EST SUN DEC 9 2012
.UPDATE...
ISSUED AT 956 AM EST SUN DEC 9 2012
THE SOUTHWARD SHIFT OF THE MODELS OVER THE LAST 18-24HRS WITH THE
SURFACE LOW AND IT TRANSFORMING INTO A SURFACE TROUGH TODAY HAS LED
TO AN INTERESTING DECISION WITH RESPECT TO SOME OF THE HAZARDS.
SNOW IS CURRENTLY SOUTHWEST OF A LINE FROM ASHLAND THROUGH
MILWAUKEE. LATEST SHORT RANGE AND HIRES MODELS INDICATING BEST
OPPORTUNITY FOR ADVISORY SNOW FROM THE SYSTEM ALONG THE WISCONSIN
BORDER AND NEAR LAKE MICHIGAN WITH SOME LAKE ENHANCEMENT LATE THIS
AFTERNOON THROUGH THE EVENING. AWAY FROM THIS AREA...VERY LOW
CONFIDENCE IN SEEING ENOUGH SNOW FOR ADVISORY CRITERIA FOR SOME
AREAS...ESPECIALLY FOR NORTHERN IRON...EASTERN GOGEBIC...SOUTHEAST
ONTONAGON AND SOUTHERN HOUGHTON COUNTIES. THEY WILL BE ON THE EDGE
OF THE BETTER SYSTEM SNOW AND AWAY FROM THE LAKE ENHANCED SNOW THAT
MAY SAVE THE ADVISORY FOR OTHER PARTS OF THE CWA NEAR LAKE SUPERIOR.
THE LAKE ENHANCEMENT WILL LIKELY INCREASE AFTER MIDNIGHT AS WINDS
TURN TO THE NORTH-NORTHEAST AND FAVOR THE WESTERN SHORELINE FROM
IRONWOOD THROUGH HOUGHTON AND THEN THE HIGHER TERRAIN OF EASTERN
BARAGA AND NORTHERN MARQUETTE COUNTIES...AND POTENTIALLY FAR WESTERN
ALGER COUNTY. THE MOST FAVORABLE PERIOD FOR LAKE ENHANCED SNOW WILL
BE LATE TONIGHT INTO THE FIRST PART OF TOMORROW MORNING. BUT...WITH
THE WINDS BACKING THROUGH TONIGHT AND MONDAY...THE OPPORTUNITY FOR
MORE THAN A BRIEF 1-3 INCHES WILL BE LIMITED.
BASED OFF LOCAL SNOW AND VEHICLE ACCIDENT DATA...EVEN SEEING 1IN OF
SNOW GREATLY INCREASES ACCIDENTS IN THE AREA. THUS...EVEN THOUGH
SOME OF THE MENTIONED AREAS OF CONCERN WILL LIKELY ONLY SEE 1-3IN OF
SNOW...WILL LEAVE THE ADVISORY IN PLACE AT THIS POINT. MADE
ADJUSTMENTS TO POPS AND SNOW AMOUNTS FOR TODAY TO BETTER MATCH
LATEST MODEL RUNS. THIS RESULTED IN A REDUCTION OF SNOW AMOUNTS IN
SOME AREAS OF AROUND 0.5-1.0IN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THROUGH AT LEAST THIS MORNING AT
ALL THE TAF SITES WITH A RIDGE OF HIGH PRES AND AXIS OF LOW LEVEL
DRY AIR DOMINATING. THEN LATER TODAY...THE APPROACH OF LOW PRES WILL
BRING SNOW AND LOWER CIGS/VSBYS SW-NE TO UPR MI. CONTINUED WITH
TREND TOWARD A SLOWER ONSET OF SN/LOWER CONDITIONS BASED ON
NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK FOR THE LOW PRES
AND MORE RESILIENT DRY AIR OVER THE NORTHERN GREAT LAKES.
ALTHOUGH SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN
AN EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS AND CONTINUE OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR
MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY UNTIL 5 PM EST /4 PM CST/ MONDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 3 AM CST MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
657 AM EST SUN DEC 9 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THROUGH AT LEAST THIS MORNING AT
ALL THE TAF SITES WITH A RIDGE OF HIGH PRES AND AXIS OF LOW LEVEL
DRY AIR DOMINATING. THEN LATER TODAY...THE APPROACH OF LOW PRES WILL
BRING SNOW AND LOWER CIGS/VSBYS SW-NE TO UPR MI. CONTINUED WITH
TREND TOWARD A SLOWER ONSET OF SN/LOWER CONDITIONS BASED ON
NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK FOR THE LOW PRES
AND MORE RESILIENT DRY AIR OVER THE NORTHERN GREAT LAKES.
ALTHOUGH SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN
AN EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS AND CONTINUE OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM NOON EST /11 AM CST/ TODAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 3 AM CST
MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST SUN DEC 9 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY MORNING) ISSUED AT
1239 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THRU AT LEAST THIS MRNG AT ALL THE
TAF SITES WITH RDG OF HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN
LATER TODAY...APRCH OF LO PRES WL BRING SN AND LOWER CIGS/VSBYS
SW-NE TO UPR MI. TENDED TO SLOW DOWN THE ONSET OF SN/LOWER
CONDITIONS BASED ON NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK
FOR THE LO PRES/MORE RESILIENT DRY AIR OVER THE UPR LKS. ALTHOUGH
SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN
EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM NOON EST /11 AM CST/ TODAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 3 AM CST
MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 AM EST SUN DEC 9 2012
.UPDATE...
ISSUED AT 739 PM EST SAT DEC 8 2012
WITH MOCLR SKIES OVER THE W HALF OF UPR MI UNDER SFC RDG AXIS/PWAT
0.18 INCH AS OBSVD ON THE 00Z GRB RAOB...SFC TEMPS HAVE ALREADY
REACHED FCST MINS EARLY THIS EVNG. SO TENDED TO LOWER THESE NUMBERS
A COUPLE OF DEGREES OVER THE W HALF BEFORE INCRSG HI CLDS FM THE SW
ARRIVE BY MIDNGT AND AT LEAST STEADY OFF THE TEMP DROP.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
HIGH PRESSURE IS CURRENTLY LOCATED IN MANITOBA AND ONTARIO...WITH A
RIDGE STRETCHING SOUTHEAST INTO WESTERN UPPER MI AND WI. LIGHT
NORTHWEST FLOW...WITH RUC ANALYZED H850 OF -10 TO -12C...HAS LED TO
LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS THROUGH THIS AFTERNOON IN
THE TRADITIONAL NORTHWEST FLOW LOCATIONS.
UPSTREAM...PV ANOMALY IN SRN SD AND NW NEBRASKA WILL SHIFT ENE
TONIGHT AND INTO MN BY 12Z SUNDAY...WITH THE SURFACE LOW FOLLOWING
SUIT. THIS ANOMALY WILL SHIFT NORTHEAST THROUGH WESTERN UPPER
MICHIGAN THROUGH THE DAY ON SUNDAY AND BE WEAKENING DUE TO INFLUENCE
OF SECOND ANOMALY ENTERING NORTHERN MN AND THE SOUTHERN WAVE
BECOMING MORE DOMINATE AS IT DIVES SOUTHEAST THROUGH THE CENTRAL
ROCKIES DURING THE DAY ON SUNDAY. THIS...COMBINED WITH A
STRENGTHENING JET OVER THE OHIO VALLEY ON SUNDAY...WILL ALLOW A
SECONDARY LOW TO DEVELOP IN THE OHIO VALLEY REGION DURING THE DAY
AND PRODUCE A BROAD AREA OF LOW PRESSURE WHICH TRANSITIONS THE LOW
OVER OUR AREA TO A TROUGH. STILL DIFFERENCES IN THE MODELS...BOTH
RUN-TO-RUN AND BETWEEN MODELS...WITH THE POTENTIAL WEAKENING/SPEED
OF THE PV ANOMALY AND THE LOCATION OF THE ASSOCIATED SURFACE TROUGH
HEADING INTO SUNDAY AFTERNOON/EVENING. LATEST TRENDS IN THE MODELS
ARE FOR A SLOWER MOVEMENT OF THE PV ANOMALY THROUGH UPPER MICHIGAN
ON SUNDAY...WHICH KEEPS THE SURFACE TROUGH AXIS OVER
NORTHERN/CENTRAL WISCONSIN.
TONIGHT...THE HIGH PRESSURE RIDGE EXITING TO THE NORTHEAST WILL
PRODUCE QUIET WEATHER BEFORE THE SYSTEM. UPSTREAM DRYING THIS
AFTERNOON HAS ATE AWAY AT SOME OF THE LAKE EFFECT CLOUDS OVER THE
WEST AND ONCE DAYTIME HEATING IS LOST...EXPECT THE SAME TO OCCUR
OVER THE INTERIOR LOCATIONS THIS EVENING. THIS CLEARING WILL MAKE
FOR TRICKY LOW TEMPERATURES TONIGHT AND FOLLOWED THE PREVIOUS SHIFT
BY TRENDED THEM DOWN A LITTLE MORE AS PWATS 65 PERCENT OF NORMAL
AND THERE ARE LIGHT WINDS. WENT WITH LOWS IN UPPER TEENS...BUT BASED
OFF HOW QUICKLY TEMPS FELL THIS MORNING IN CLEARING AREAS...THAT MAY
NOT BE COLD ENOUGH. OTHERWISE...MID/HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE SOUTHWEST WITH THE APPROACHING SYSTEM.
SUNDAY...PRECIPITATION BUILDS IN FROM SOUTHWEST TO NORTHEAST THROUGH
THE DAY. STARTING BETWEEN 12-15Z NEAR KIWD...LATE MORNING OR EARLY
AFTERNOON OVER THE CENTRAL...AND MID/LATE AFTERNOON OVER THE EAST.
WITH THE LATEST SLOWER TRENDS...HAVE DELAYED THE START A COUPLE OF
HOURS FROM THE PREVIOUS SHIFT. PLENTY OF COLD AIR ALOFT...SO EXPECT
PRECIPITATION TO BE AS ALL SNOW. AS FOR FORCING...BEST MID LEVEL WAA
IS FOCUSED OVER THE SOUTH CENTRAL AND NEAR LAKE MICHIGAN THROUGH
THE DAY. THIS LINES UP WITH WEAK FGEN BETWEEN H850-650 OVER THE AREA
FOR THE AFTERNOON...BUT SEEMS TO FOCUS OVER THE SOUTHEAST HALF OF
THE CWA LATE IN THE AFTERNOON. IN ADDITION...BROAD 280-290K
ISENTROPIC ASCENT WILL SPREAD OVER THE CWA DURING THE DAY.
FINALLY...H850 TEMPS AROUND -9C SHOULD FAVOR SOME LAKE ENHANCEMENT
FOR THE KEWEENAW AND ALSO FOR LOCATIONS NEAR LAKE MICHIGAN FAVORED
BY ESE WINDS.
WITH THE SLIGHT DELAY WITH THE SLOWER ARRIVAL OF THE PV ANOMALY AND
SURFACE TROUGH BEING A LITTLE FARTHER SOUTH...BEST PRECIPITATION
STRADDLES THE SHORT/LONG TERM TRANSITION. ALL IN ALL...MODEL QPF
FOR SUNDAY INTO SUNDAY NIGHT WITH THE SYNOPTIC FEATURES IS IN THE
0.25-0.4IN FOR MOST AREAS AND WHEN COMBINED WITH A SNOW RATIO AROUND
13-15 TO 1...WOULD PUT 3 TO 6 INCHES OF SYNOPTIC SNOW OVER THE
AREA THROUGH SUNDAY EVENING. OUTSIDE OF ANY LAKE ENHANCEMENT...THE
HIGHEST AMOUNTS SHOULD LINE UP ALONG THE WISCONSIN BORDER WITH THE
SLIGHT SOUTH SHIFT OF THE SURFACE TROUGH. THE LONG TERM DISCUSSION
WILL COVER THE BULK OF THE HEADLINES...BUT DID DROP THE WATCH OVER
THE WESTERN COUNTIES AND HAVE STARTED A LONGER PERIOD ADVISORY FROM
WEST TO EAST THROUGH THE DAY ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
MAIN CONCERN IS WITH SNOWFALL FORECAST FOR THE FIRST 24 HOURS OF THE
LONG TERM.
SUN NIGHT/MON...IN GENERAL...MODELS ARE IN GOOD AGREEMENT...BUT
THERE ARE SUBTLE VARIATIONS AT SMALLER SCALES THAT BECOME MAGNIFIED
IN THE SNOWFALL FORECAST. THE DIFFICULTY AND UNCERTAINTY IS DUE TO
THE FACT THAT THE SYSTEM OVER THE REGION SUN NIGHT WILL BE MERGING
WITH A SRN STREAM SYSTEM OVER THE OHIO VALLEY...PLUS THE FACT THAT
MODELS HAVE A HARD TIME CONSISTENTLY HANDLING THE PV ANOMALIES THAT
WILL DRIVE A GOOD PORTS OF THE SNOWFALL WITH THIS SYSTEM. LATEST
RUNS OF THE GFS/NAM/REGIONAL GEM/REGIONAL WRF ARE NOW IN BETTER
AGREEMENT IN BRINGING THE WEAKENING PRIMARY PV ANOMALY FROM NW WI AT
00Z MON TO CENTRAL UPPER MI AROUND 06Z MON...THEN SHEARING IT OUT
AND PUSHING IT NORTHEAST BY 12Z MON. MEANWHILE...THE SECONDARY PV
ANOMALY WILL ROTATE INTO CENTRAL/SRN WI...FARTHER S THAN PREVIOUS
RUNS OF THE MODELS. THE TIMING/LOCATION OF THE PV ANOMALIES IS
CONSISTENT WITH THE OVERALL TREND OVER THE LAST FEW RUNS OF THE
MODELS IN SLOWING THE SYSTEM DOWN AND MOVING IT FARTHER S. THE
RESULTING SFC TROUGH LOOKS TO STAY TO THE S OF THE CWA OVER
CENTRAL/NRN WI. LOW LEVEL FLOW WILL GENERALLY BE ELY AT 00Z MON WITH
850MB TEMPS AROUND -9C. BY 06Z MON...LOW LEVEL WINDS BACK TO MORE
ENE...THEN TO NNE BY 12Z MON AS 850MB TEMPS FALL TO -11C. SYNOPTIC
SNOWFALL AMOUNTS WILL BE HIGHEST OVER THE SRN HALF OF UPPER MI SUN
NIGHT...BUT THAT SHOULD BE OFFSET SOME BY UPSLOPE FLOW IN SOME NRN
LOCATIONS...PARTICULARLY NCENTRAL UPPER MI AND THE KEWEENAW...THEN
OVER THE WRN U.P. LATER SUN NIGHT. 850MB TEMPS FALL ANOTHER COUPLE
OF DEGREES THROUGH THE DAY MON WHILE FLOW BECOMES INCREASING
ANTICYCLONIC AS THE SFC TROUGH MOVES QUICKLY E AND A RIDGE MOVES
OVER WRN LAKE SUPERIOR BY 00Z TUE. THUS...EXPECT LES FROM NNW WINDS
MON MORNING...DIMINISHING THROUGH MON EVENING. WITH THIS TYPE OF
SYSTEM THERE IS INHERENT UNCERTAINTY THAT WILL PROBABLY NOT BE
RESOLVED UNTIL THE SYSTEM IS ON THE DOORSTEP OF THE CWA...SO
CONFIDENCE IN SNOWFALL AMOUNTS IS STILL SOMEWHAT LIMITED. STORM
TOTAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES IS EXPECTED...WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN OF WRN
GOGEBIC/ONTONAGON COUNTIES AND NW MARQUETTE/NE BARAGA COUNTIES.
DECIDED IN COORDINATION WITH SHORT TERM SHIFT TO ISSUE WINTER WX
ADVISORIES OVER THE ENTIRE CWA. COULD SEE SOME LOCATIONS GO SLIGHTLY
ABOVE ADVISORY CRITERIA...BUT NOT CONFIDENT ENOUGH IN THAT TO
JUSTIFY WARNING. ALSO...THE TIME THAT THE HEAVIEST SNOW WILL FALL
/SUN EVENING AND EARLY SUN NIGHT/ IS NOT A HIGH IMPACT TIME TRAVEL
WISE...PLUS THE FACT THAT THE STORM TOTAL WILL OCCUR OVER 24 HOURS
OR MORE. ALSO DECIDED ON THE ADVISORY WITH THE IDEA THAT IT WOULD BE
EASIER TO UPGRADE TO A WARNING IF NEEDED THAN HAVE TO CANCEL
WARNINGS AND ISSUE AN ADVISORY IF THE BORDERLINE WARNING AMOUNTS DO
NOT OCCUR...WHICH WOULD LEAD TO A MISSED EVENT FOR
VERIFICATION...SORT OF THE PATH OF LEAST REGRET.
A VERY WEAK SHORTWAVE TROUGH MOVES ACROSS THE AREA TUE INTO TUE
NIGHT...BRINGING SE FLOW OFF LAKE MICHIGAN FROM 12Z TUE INTO WED.
THIS SHOULD LEAD TO LES OFF LAKE MI INTO ERN UPPER MI...ESPECIALLY
SERN SCHOOLCRAFT COUNTY. INVERSION HEIGHTS SHOULD BE AROUND 10KFT
ACCORDING TO THE NAM/GFS WITH UNIDIRECTIONAL WINDS. THE RESULTING
LES BAND SHOULD BE A LARGER MORE DOMINANT ONE...BUT SHOULD ALSO NOT
STAY IN ONE PLACE TOO LONG AS WINDS STEADILY VEER. EVEN SO...MAY END
UP BEING CLOSE TO ADVISORY AMOUNTS. WINDS WILL BECOME WLY ENOUGH
BEHIND THE TROUGH BY 06Z WED TO BRING LES TO NW UPPER MI...BUT WINDS
QUICKLY BECOME ANTICYCLONIC BY 12Z WED AS A SFC RIDGE MOVES TO WRN
LAKE SUPERIOR...SO LIGHTER SNOW AMOUNTS ARE EXPECTED THERE.
A SLIGHTLY STRONGER SYSTEM WILL MOVE N OF THE AREA THU AND DRAW
WARMER TEMPS IN THE CWA...BUT NO SIGNIFICANT PRECIP IS EXPECTED.
HIGHS IN THE MID TO UPPER 30S SEEMS REASONABLE. PRETTY QUIET AFTER
THAT UNTIL MODELS INDICATE A MUCH STRONGER LOW PRESSURE SYSTEM
MOVING NEARBY ON SAT. MODELS ARE IN GOOD AGREEMENT FOR HOW FAR OUT
THE SYSTEM IS...SO WILL USE CONSENSUS OF MODELS FOR THE FORECAST
PAST TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1239 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THRU AT LEAST THIS MRNG AT ALL THE
TAF SITES WITH RDG OF HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN
LATER TODAY...APRCH OF LO PRES WL BRING SN AND LOWER CIGS/VSBYS
SW-NE TO UPR MI. TENDED TO SLOW DOWN THE ONSET OF SN/LOWER
CONDITIONS BASED ON NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK
FOR THE LO PRES/MORE RESILIENT DRY AIR OVER THE UPR LKS. ALTHOUGH
SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN
EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT DEC 8 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHWEST SOUTH DAKOTA WILL
ENTER MN TOMORROW MORNING AND THEN MERGE WITH A LOW DEVELOPING IN
THE GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS
TROUGH WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST
DIRECTION SUNDAY INTO SUNDAY NIGHT. AT THIS TIME...THINKING WINDS
WILL BE IN THE 20-30KT RANGE...ALTHOUGH THERE COULD BE A FEW GALE
FORCE GUSTS TO 35KTS OVER THE WEST AS THE TROUGH SHARPENS LATE
SUNDAY NIGHT. BEHIND THIS FEATURE...A SERIES OF WEAK RIDGES AND
TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST OF THE WORK WEEK
AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ THIS MORNING TO
5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 3 AM CST MONDAY FOR
MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...TITUS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1237 PM CST SUN DEC 9 2012
.UPDATE...UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION.../ISSUED 1012 AM CST SUN DEC 9 2012/
.UPDATE...
INCREASED THE SNOW AMOUNTS FOR TODAY INTO THIS EVENING DUE TO A
SLOWER TREND OF THIS SYSTEM EXITING...IMPRESSIVE FORCING...HIGH
QPF NUMBERS...AND WHAT HAS ALREADY BEEN REPORTED. MANY REPORTS OF
6 TO 10 INCHES HAVE BEEN RECEIVED ACROSS CENTRAL AND WESTERN
MINNESOTA WITH AT LEAST ANOTHER 3 TO 6 INCHES EXPECTED TODAY AND
THIS EVENING. FURTHER EAST TOWARD THE TWIN CITIES METRO AND FAR
WRN WI...3 TO 4 INCHES WERE REPORTED THIS MORNING WITH ANOTHER 7 TO
10 EXPECTED TODAY AND THIS EVENING. THUS...HAVE A LARGE SWATH OF 9
TO 15 INCHES ACROSS MOST OF THE CWA...EXCEPT FOR FAR SOUTHERN
MINNESOTA WHERE RADAR AND SATELLITE INDICATES A DRY SLOT BEGINNING
TO MOVE IN. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. THE
LOW WILL CONTINUE TRACKING DUE EAST ACROSS FAR SRN MN TODAY...SO
WILL LEAVE THE HEADLINES AS THEY ARE WITH WARNINGS NORTH OF THE
LOW TRACK AND AN ADVISORY ALONG AND SOUTH.
A ROBUST INCREASE IN SNOW INTENSITY HAS OCCURRED IN THE PAST 30 TO
60 MINUTES FROM THE TC METRO SOUTHWEST TO REDWOOD FALLS. EXPECT
RATES WITHIN THIS AREA TO REACH 1 TO 2 INCHES PER HOUR THROUGH THE
REST OF THE MORNING INTO THE EARLY AFTERNOON WITH ADDITIONAL HEAVY
SNOW JUST NORTH OF THE LOW TRACK LATE THIS AFTERNOON AND EARLY
THIS EVENING.
STRONG COLD FRONT ALONG THE MN BORDER WILL BEGIN PUSHING EAST THIS
AFTERNOON. TEMPERATURES WEST OF THE BOUNDARY ARE IN THE SINGLE
DIGITS WITH NORTH WINDS GUSTING HIGHER THAN 30 KTS. WHITEOUT
CONDITIONS HAVE BEEN REPORTED OVER EASTERN SD. AS THE LOW PULLS
EAST...EXPECT AREAS ACROSS SWRN MN TO FOLLOW SUIT. WITH REPORTS OF
6 TO 10 INCHES OVER FAR WRN MN AND SEVERAL MORE POSSIBLE...DRIFTS
WILL BE RATHER SIGNIFICANT AND TRAVEL WILL BECOME IMPOSSIBLE.
UPDATED THE GRIDS FOR THESE CURRENT TRENDS...INCLUDING EXTENDING
THE HEAVY SNOW INTO THE EVENING ACROSS THE EAST.
BORGHOFF
&&
.PREV DISCUSSION... /ISSUED 539 AM CST SUN DEC 9 2012/
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
WIDESPREAD MODERATE TO HEAVY SNOW CONTINUES THIS AFTERNOON FOR
MOST OF THE TERMINALS. DRY SLOT AS SEEN ON RADAR IS APPROACHING
RWF...BUT WILL PROBABLY STALL JUST SOUTH. NONE OF THE OTHER
TERMINALS ARE EXPECTED TO BE IMPACTED BY A DRY SLOT AND WILL
CONTINUE SNOWING FOR THE NEXT 6 TO 9 HOURS. BLIZZARD CONDITIONS
ARE HEADED EAST ACROSS THE MN/SD BORDER AND COULD IMPACT RWF AND
AXN LATER THIS AFTERNOON AND EARLY EVENING WITH SOME GUSTS TO 30
OR 35 KTS. PUSHED BACK THE CLEARING AND IMPROVING VISIBILITIES A
COUPLE HOURS OVER ERN MN AND WRN WI WITH LINGERING SNOW. VFR
CONDITIONS WILL REACH AXN AND RWF LATER TONIGHT...STC BY MONDAY
MORNING...AND NOT UNTIL MONDAY AFTERNOON AT MSP/RNH/EAU.
KMSP...
A SOLID AREA OF +SN CONTINUES TO ENGULF THE TERMINAL...WHICH IS
EXPECTED TO CONTINUE FOR THE MAJORITY OF THE AFTERNOON JUST NORTH
OF THE LOW TRACK. DRY SLOT AS EVIDENT ON RADAR IS APPROACHING...
BUT THINK IT WILL FILL IN NORTH OF THE LOW KEEPING SNOW GOING ALL
AFTERNOON. SNOW WILL TAPER OFF THIS EVENING WITH OCCASIONAL LIGHT
SNOW OR FLURRIES CONTINUING OVERNIGHT. SOME BLOWING SNOW IS
POSSIBLE...BUT BEST CHANCES REMAIN WELL WEST. CLEARING SKIES AND
IMPROVING CIGS WILL ARRIVE BY LATE MORNING MONDAY WITH VFR
EXPECTED THEREAFTER. WINDS WILL BACK FROM EAST TO NORTH THIS
AFTERNOON AND THEN BECOME WEST BY MONDAY AFTERNOON.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR BROWN-CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-NICOLLET-POPE-
REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/BORGHOFF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1012 AM CST SUN DEC 9 2012
.UPDATE...
INCREASED THE SNOW AMOUNTS FOR TODAY INTO THIS EVENING DUE TO A
SLOWER TREND OF THIS SYSTEM EXITING...IMPRESSIVE FORCING...HIGH
QPF NUMBERS...AND WHAT HAS ALREADY BEEN REPORTED. MANY REPORTS OF
6 TO 10 INCHES HAVE BEEN RECEIVED ACROSS CENTRAL AND WESTERN
MINNESOTA WITH AT LEAST ANOTHER 3 TO 6 INCHES EXPECTED TODAY AND
THIS EVENING. FURTHER EAST TOWARD THE TWIN CITIES METRO AND FAR
WRN WI...3 TO 4 INCHES WERE REPORTED THIS MORNING WITH ANOTHER 7 TO
10 EXPECTED TODAY AND THIS EVENING. THUS...HAVE A LARGE SWATH OF 9
TO 15 INCHES ACROSS MOST OF THE CWA...EXCEPT FOR FAR SOUTHERN
MINNESOTA WHERE RADAR AND SATELLITE INDICATES A DRY SLOT BEGINNING
TO MOVE IN. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. THE
LOW WILL CONTINUE TRACKING DUE EAST ACROSS FAR SRN MN TODAY...SO
WILL LEAVE THE HEADLINES AS THEY ARE WITH WARNINGS NORTH OF THE
LOW TRACK AND AN ADVISORY ALONG AND SOUTH.
A ROBUST INCREASE IN SNOW INTENSITY HAS OCCURRED IN THE PAST 30 TO
60 MINUTES FROM THE TC METRO SOUTHWEST TO REDWOOD FALLS. EXPECT
RATES WITHIN THIS AREA TO REACH 1 TO 2 INCHES PER HOUR THROUGH THE
REST OF THE MORNING INTO THE EARLY AFTERNOON WITH ADDITIONAL HEAVY
SNOW JUST NORTH OF THE LOW TRACK LATE THIS AFTERNOON AND EARLY
THIS EVENING.
STRONG COLD FRONT ALONG THE MN BORDER WILL BEGIN PUSHING EAST THIS
AFTERNOON. TEMPERATURES WEST OF THE BOUNDARY ARE IN THE SINGLE
DIGITS WITH NORTH WINDS GUSTING HIGHER THAN 30 KTS. WHITEOUT
CONDITIONS HAVE BEEN REPORTED OVER EASTERN SD. AS THE LOW PULLS
EAST...EXPECT AREAS ACROSS SWRN MN TO FOLLOW SUIT. WITH REPORTS OF
6 TO 10 INCHES OVER FAR WRN MN AND SEVERAL MORE POSSIBLE...DRIFTS
WILL BE RATHER SIGNIFICANT AND TRAVEL WILL BECOME IMPOSSIBLE.
UPDATED THE GRIDS FOR THESE CURRENT TRENDS...INCLUDING EXTENDING
THE HEAVY SNOW INTO THE EVENING ACROSS THE EAST.
BORGHOFF
&&
.PREV DISCUSSION...
/ISSUED 539 AM CST SUN DEC 9 2012/
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
OVER THE NEXT 6 HRS...CONDS WILL DETERIORATE RAPIDLY WITH MOST TAF
SITES GOING TO NEAR MINIMUMS. STORM SYSTEM WAS BEGINNING TO
DEVELOP A STRONG CIRCULATION NORTHWEST OF KFSD WITH A LARGE AREA
OF ENERGY THAT WILL LIFT TO THE E/NE DURING THE MORNING. SNOWFALL
RATES WILL LIKELY INCREASE TO 1...OR EVEN 2 INCHES PER HOUR DURING
THE HEIGHT OF THE STORM. TAFS ARE BASED ON CURRENT RAP MODEL SFC
WINDS AND FORECAST REFLECTIVITY OF THE SPC/WRF. AXN WILL LIKELY BE
ON THE NW SIDE OF THE LOWEST CIGS/VSBYS...WITH STC/RNH/MSP LIKELY
THE WORSE AREA DURING THE 15-03Z TIME FRAME. AS THE STORM SYSTEM
MOVES EASTWARD ACROSS SOUTHERN MN TODAY...EXPECT A BAND OF
MODERATE TO HEAVY SNOWFALL ALONG A LINE FROM KMVE TO KMGG TO KOEO.
AS THE STORM BEGINS TO PIVOT...EXPECT THE BANDS OF SNOW TO SLOWLY
MOVE FROM THE WEST TO THE EAST...THEN SE AS THE STORM MOVES OFF TO
THE WESTERN GREAT LAKES. THERE WILL BE A PERIOD OF 1/4SM +SN AND
VV002 OR LOWER. EXPECT SFC WINDS TO INCREASE AT AXN BY
15-18Z...THAN AT RWF BY 18-21Z. AFT 00-03Z CONDS WILL SLOWLY
IMPROVE WITH IFR...OR MVFR CIGS/VSBYS WITH BLSN CONTINUING
ACROSS AXN/RWF.
KMSP...
THERE IS A 3 HR PERIOD OF IFR/MVFR CONDS WITH -SN...BUT AFT 15Z
EXPECT CONDS TO DETERIORATE RAPIDLY WITH VSBYS DROPPING TO LESS
THAN 3/4SM AND CIGS LOWERING TO 500` OR EVEN LOWER. THERE IS A
PERIOD DURING THE AFTN WHERE VSBYS COULD DROP TO 1/4SM +SN AND
VV002. SFC WINDS WILL BE PREDOMINATE FROM THE E/SE THIS
MORNING/AFTN WITH SOME GUSTS OVER 20 KTS POSSIBLE BY MID MORNING.
WINDS WILL SHIFT TO THE E/NE AFT 21Z...THEN BECOME N/NNE BY 00-03Z
AND GUSTY. EVENTUALLY WINDS WILL SHIFT TO THE N/NNW AFT 06Z WITH
CIGS/VSBYS SLOWLY IMPROVING. DECIDED NOT TO INCLUDE A TEMPORARY
GROUP DUE TO UNCERTAINTIES OF TIMING OF WHEN THE WORSE CONDS
DEVELOP THIS MORNING/AFTN. TAFS WILL LIKELY BE AMD AS THIS SYSTEM
EVOLVES.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR BROWN-CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-NICOLLET-POPE-
REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
539 AM CST SUN DEC 9 2012
.DISCUSSION...
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
OVER THE NEXT 6 HRS...CONDS WILL DETERIORATE RAPIDLY WITH MOST TAF
SITES GOING TO NEAR MINIMUMS. STORM SYSTEM WAS BEGINNING TO
DEVELOP A STRONG CIRCULATION NORTHWEST OF KFSD WITH A LARGE AREA
OF ENERGY THAT WILL LIFT TO THE E/NE DURING THE MORNING. SNOWFALL
RATES WILL LIKELY INCREASE TO 1...OR EVEN 2 INCHES PER HOUR DURING
THE HEIGHT OF THE STORM. TAFS ARE BASED ON CURRENT RAP MODEL SFC
WINDS AND FORECAST REFLECTIVITY OF THE SPC/WRF. AXN WILL LIKELY BE
ON THE NW SIDE OF THE LOWEST CIGS/VSBYS...WITH STC/RNH/MSP LIKELY
THE WORSE AREA DURING THE 15-03Z TIME FRAME. AS THE STORM SYSTEM
MOVES EASTWARD ACROSS SOUTHERN MN TODAY...EXPECT A BAND OF
MODERATE TO HEAVY SNOWFALL ALONG A LINE FROM KMVE TO KMGG TO KOEO.
AS THE STORM BEGINS TO PIVOT...EXPECT THE BANDS OF SNOW TO SLOWLY
MOVE FROM THE WEST TO THE EAST...THEN SE AS THE STORM MOVES OFF TO
THE WESTERN GREAT LAKES. THERE WILL BE A PERIOD OF 1/4SM +SN AND
VV002 OR LOWER. EXPECT SFC WINDS TO INCREASE AT AXN BY
15-18Z...THAN AT RWF BY 18-21Z. AFT 00-03Z CONDS WILL SLOWLY
IMPROVE WITH IFR...OR MVFR CIGS/VSBYS WITH BLSN CONTINUING
ACROSS AXN/RWF.
KMSP...
THERE IS A 3 HR PERIOD OF IFR/MVFR CONDS WITH -SN...BUT AFT 15Z
EXPECT CONDS TO DETERIORATE RAPIDLY WITH VSBYS DROPPING TO LESS
THAN 3/4SM AND CIGS LOWERING TO 500` OR EVEN LOWER. THERE IS A
PERIOD DURING THE AFTN WHERE VSBYS COULD DROP TO 1/4SM +SN AND
VV002. SFC WINDS WILL BE PREDOMINATE FROM THE E/SE THIS
MORNING/AFTN WITH SOME GUSTS OVER 20 KTS POSSIBLE BY MID MORNING.
WINDS WILL SHIFT TO THE E/NE AFT 21Z...THEN BECOME N/NNE BY 00-03Z
AND GUSTY. EVENTUALLY WINDS WILL SHIFT TO THE N/NNW AFT 06Z WITH
CIGS/VSBYS SLOWLY IMPROVING. DECIDED NOT TO INCLUDE A TEMPORARY
GROUP DUE TO UNCERTAINTIES OF TIMING OF WHEN THE WORSE CONDS
DEVELOP THIS MORNING/AFTN. TAFS WILL LIKELY BE AMD AS THIS SYSTEM
EVOLVES.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM THIS MORNING TO MIDNIGHT CST TONIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-
MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
413 AM CST SUN DEC 9 2012
.DISCUSSION...
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECASTED TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTOGENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../06Z TAF ISSUANCE/
SIGNIFICANT SOUTHERN SHIFT ALONG WITH A BIT OF A SLOWING OCCURRED
WITH 00Z MODEL RUNS AND THIS PLACES ALL MPX TERMINALS WITHIN THE
HEART OF WHAT LOOKS TO BE AN IMPRESSIVE SNOW BAND...WITH 6-10 INCH
SNOW TOTALS /AND POSSIBLY MORE AT STC...MSP...RNH/ NOW EXPECTED. SFC
LOW RIGHT NOW IS CENTERED ALONG I-90 NEAR CHAMBERLAIN...SD. 00Z
NAM/GFS ALONG WITH THE RAP TRACK THIS LOW RIGHT DOWN I-90 THROUGH
THE DAY SUNDAY...PLACING THE MPX TERMINALS WITHIN THE HEAVIEST
SNOW. HAVE ALREADY BEEN GETTING SNOWFALL RATES OF AN INCH PLUS PER
HOUR IN WRN MN...SO CONTINUED TO ADVERTISE PROLONGED PERIODS OF
1/2SM VIS AT ALL TERMINALS...BUT TENDED TO SHIFT THAT MENTION OUT
IN TIME WITH THE SLOWING. ANOTHER ASPECT OF THE SLOWING WAS THE
NEED TO SLOW THE BACKING OF WINDS FROM THE EAST OVER TO THE
NW...ALONG WITH A TEMPERING OF SPEEDS SOME...AS NAM NOW SHOWING
GUST POTENTIAL GREATER THAN 35 KTS AT ONLY RWF. AS THIS TAF PERIOD
COMES TO AN END...CLEARING WILL START WORKING INTO WRN MN...WITH
VFR CONDITIONS EXPECTED AS WE START GOING A LITTLE BEYOND THIS TAF
PERIOD.
KMSP...ALL GUIDANCE NOW PUTTING MSP IN THE CROSS-HAIRS FOR THE
HEAVIEST SNOW WITH THIS EVENT...SO SIGNIFICANTLY DEGRADED
TAF...WITH LIFR VIS SNOW NOW EXTENDING WELL OUT INTO THE
AFTERNOON. LOOKING AT THE NAM ALONG WITH CURRENT RADAR...EXPECTING
TWO BURSTS OF SNOW THIS PERIOD. FIRST WILL COME BETWEEN 8Z AND 12Z
AS WARM ADVECTIVE WING OF PRECIP SWINGS THROUGH...WITH THE
NEXT...MORE PROLONGED BOUT OF HEAVY SNOW HITTING BETWEEN 14Z AND
22Z AS THE MAIN UPPER FORCING MOVES IN. THIS IS WHEN MAJORITY OF
ACCUMULATIONS SHOULD OCCUR...WITH SEVERAL OF THESE HOURS LIKELY
SEEING RATES AROUND 1 INCH AN HOUR. THIS TAF MAY A BIT PESSIMISTIC
WITH THE LENGTH OF 1/2SM VIS...BUT FEEL PRETTY CONFIDENT IN
WINDOWS OF HEAVIER SNOW THAT ARE INDICATED WITH TAF. AVIATION
WEATHER WARNING WILL ALSO BE ISSUED SHORTLY FOR ACCUMULATIONS
EXCEEDING 3/4 OF AN INCH PER HOUR. AS FOR STORM TOTAL...WOULD PUT
MSP ON THE HIGHER END OF THE SCALE WITH 8-10 INCHES LOOKING MORE
AND MORE LIKELY.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. WINDS SW AT 10G15KTS.
WED...VFR. WINDS SE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM THIS MORNING TO MIDNIGHT CST TONIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-
MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1135 PM CST SAT DEC 8 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 447 PM CST SAT DEC 8 2012/
..DANGEROUS WINTER STORM TO IMPACT THE UPPER MISSISSIPPI VALLEY
TONIGHT THROUGH SUNDAY NIGHT...
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
LOW PRESSURE LOCATED NEAR VALENTINE NEBRASKA LATE THIS AFTERNOON WILL
TRACK ALMOST DUE EAST TONIGHT AND SUNDAY...TRACKING ROUGHLY ALONG
THE I-90 CORRIDOR. THIS IS A SIGNIFICANT SHIFT SOUTH FROM WHAT
MODELS WERE SHOWING YESTERDAY...WITH THE NAM REMAINING THE LONE
NORTHERN OUTLIER TRACKING IT ACROSS THE TWIN CITIES METRO. IN
ADDITION...QPF HAS INCREASED MARKEDLY FROM 00Z RUNS AND NOW
AVERAGES BETWEEN A HALF AND AT LEAST THREE QUARTERS OF AN INCH
FROM WILLMAR TO NEAR LADYSMITH...OR JUST NORTH OF THE METRO.
ELSEWHERE...QPF AVERAGES 0.3 TO 0.5 INCHES. THE 18Z GFS IS COMING
IN SURPRISINGLY HIGH AT NEARLY ONE INCH AND AGAIN JUST A BIT FURTHER
SOUTH FROM PREVIOUS RUNS...NOW THROUGH THE METRO. EVEN THE EC WHICH
WAS THE DRY OUTLIER YESTERDAY IS SHOWING AT LEAST 0.6 INCHES OVER
MUCH OF THE CENTRAL AREAS. MODEL INCONSISTENCY FROM RUN TO RUN
SHOULD NOW BE ABOUT COMPLETE...LEAVING A VERY HIGH PROBABILITY
FOR A MAJOR WINTER STORM ACROSS MUCH OF THE AREA TONIGHT INTO
SUNDAY EVENING.
THE ARC OF SNOW EXPECTED TO PROPAGATE INTO WESTERN MINNESOTA DURING
THE NEXT FEW HOURS IS EXPANDING IN SIZE AND PRODUCING MODERATE TO
HEAVY SNOWFALL RATES WITHIN EMBEDDED BANDS. WITH TIME...THIS AREA
OF SNOW WILL EXPAND WITH WIDESPREAD MODERATE TO HEAVY SNOW
EXPECTED TO SPREAD EAST ACROSS THE AREA LATER THIS EVENING AND
OVERNIGHT. FRONTOGENESIS WITHIN THE DENDRITIC GROWTH ZONE IS
RATHER IMPRESSIVE SO EMBEDDED BANDS OF VERY HEAVY SNOW WITH
GREATER THAN ONE INCH HOURLY RATES ARE POSSIBLE THROUGH SUNDAY
MORNING. BECAUSE THE TRACK OF THE LOW WILL BE CONFINED TO ABOUT
I-90...THE THREAT FOR DRY SLOTTING INTO THE SOUTHERN AREAS IS A
BIT LOWER ALTHOUGH STILL POSSIBLE FOR THE SOUTHERN TWO TIERS OF MN
COUNTIES COME SUNDAY MORNING. STORM TRACK HAS SLOWED A BIT AS
WELL...THUS DEFORMATION SNOW WILL HELP PILE ON THE INCHES A BIT
LONGER THAN ANTICIPATED YESTERDAY. OCCASIONAL SNOW OR SNOW SHOWERS
ARE EXPECTED THROUGH AT LEAST EARLY SUNDAY AFTERNOON AND POSSIBLY
THROUGH THE EVENING OVER WESTERN WISCONSIN.
PREDICTED SNOWFALL AMOUNTS MAY BE CONSERVATIVE IF THE HIGHER QPF
DEPICTIONS PAN OUT...BUT STILL EXPECTING 6 TO 9 INCHES ACROSS
CENTRAL MN AND WESTERN WISCONSIN...AND 3 TO 5 INCHES NEAR THE
IOWA BORDER. COULD SEE SOME ISOLATED TOTALS EXCEED 9 OR 10 INCHES
IN LOCALLY FAVORED BANDING AREAS.
THEREFORE...EXPANDED THE WINTER STORM WARNING SOUTH TO ABOUT A
LINE FROM REDWOOD FALLS...TO RED WING..AND EAU CLAIRE WITH A
WINTER WEATHER ADVISORY SOUTH OF THAT TO THE IOWA BORDER. THESE
HEADLINES DEAL WITH SNOWFALL TOTALS ONLY.
THE BIG CHANGE TO THIS FORECAST PACKAGE WAS TO ISSUE A BLIZZARD
WARNING FROM LATE SUNDAY MORNING THROUGH SUNDAY EVENING WEST OF A
LINE FROM ALEXANDRIA TO WILLMAR AND MANKATO. MODELS HAVE BEEN
CONSISTENT IN SHOWING POTENTIAL FOR 40 KT WINDS WITHIN THE MIXED
LAYER BEHIND THE SYSTEM AND THINK GUSTS TO AT LEAST 35 KTS WILL BE
FREQUENT. COUPLE THAT WITH FRESHLY FALLEN SNOW AND POTENTIALLY
ADDITIONAL LIGHT SNOW...CONFIDENCE HAS INCREASED THAT BLIZZARD
CONDITIONS WILL BE COMMON WITH NEAR ZERO VISIBILITIES IN OPEN
AREAS SUNDAY AFTERNOON AND EARLY EVENING /ESPECIALLY IF GUSTS
EXCEED 45 MPH/. TEMPERATURES WILL PLUMMET BELOW ZERO SUNDAY
EVENING AS WELL...THREATENING THE LIVES OF ANY STUCK TRAVELERS.
KEPT THE BLIZZARD WARNING CONFINED TO AREAS WITH A HIGH
LIKELIHOOD OF AT LEAST 4 INCHES OF SNOW WHICH IS GENERALLY NEEDED
FOR CONSIDERABLE BLOWING AND DRIFTING.
THE SYSTEM WILL PULL OUT SUNDAY NIGHT AS THE RIDGE QUICKLY BUILDS
INTO THE WEST. SOME SNOW IS STILL POSSIBLE OVER WRN WI IN CYCLONIC
FLOW...BUT CLEARING SKIES WILL ALLOW FOR A BITTER COLD NIGHT WITH
LOWS IN THE TEENS BELOW OVER WRN MN AND NEAR ZERO AS FAR EAST AS
I-35. WINDS SHOULD REMAIN ELEVATED ENOUGH TO BRING WIND CHILL
VALUES DOWN INTO THE 20S AND POSSIBLY LOW 30S BELOW NEAR THE SOUTH
DAKOTA BORDER...WITH TEENS BELOW TO I-35. WIND CHILL ADVISORIES
WILL BE NEEDED AFTER THE OTHER WINTER HEADLINES EXPIRE.
WILL REMAIN COLD DESPITE SUNSHINE ON MONDAY UNDER THE RIDGE
AXIS...BUT RETURN FLOW MONDAY EVENING SHOULD KEEP TEMPS STEADY OR
SLOWLY RISE OVERNIGHT. A WEAK SYSTEM PASSING THROUGH THE UPPER
MISSISSIPPI VALLEY TUESDAY COULD BRING A LITTLE LIGHT SNOW OR
FLURRIES WITH NO ACCUMULATIONS ARE EXPECTED.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
UPPER LEVEL RIDGING WILL BE IN PLACE ACROSS THE GULF OF ALASKA BY
MIDWEEK...WITH A DEEP TROUGH DIGGING DOWN THE WEST COAST.
SOUTHWEST FLOW WILL STREAM ACROSS THE CENTRAL CONUS...WITH WARM
AIR ADVECTION SPREADING OVERHEAD ALLOWING HIGH TEMPS TO MAKE A RUN
AT THE THAWING MARK FOR BOTH WEDNESDAY AND THURSDAY. BY FRIDAY A
WELL ESTABLISHED EAST/WEST TEMPERATURE GRADIENT WILL BE IN PLACE
OVER THE UPPER MIDWEST...AND THE AFOREMENTIONED WEST COAST TROUGH
WILL MOVE INLAND OVER THE FOUR CORNERS REGION. THIS WILL BE THE
MAIN PLAYER IN THE WEEKEND WEATHER AS BOTH THE GFS AND ECMWF 08.12
EJECT THIS WAVE TOWARDS THE GREAT LAKES REGION. THIS PV ANOMALY
WILL ACT ON THE LOW LEVEL TEMPERATURE GRADIENT AND CAUSE A SURFACE
CYCLONE TO DEVELOP AND TRACK SOUTH AND EAST OF THE CWA. THIS WOULD
PUT CENTRAL MINNESOTA AND WESTERN WISCONSIN IN A FAVORABLE REGION
FOR ANOTHER POTENTIAL WEEKEND SNOW STORM. FORECAST SOUNDINGS AND
NORTH/SOUTH CROSS SECTIONS VIA THE GFS SHOW A WARM LAYER CENTERED
AROUND H850 WITH THE 0C LINE EXTENDING AS FAR NORTH AS THE METRO
AREA. THEREFORE HAVE INCLUDED THE CHANCE OF MIXED PRECIP FOR
SATURDAY MORNING ACROSS THE SOUTHEAST HALF OF THE CWA WITH THE
INITIAL SURGE OF LOW LEVEL THETA_E ADVECTION...AND THEN TRANSITION
TO ALL SNOW BY THE AFTERNOON. ALSO INCREASED POPS ABOVE GUIDANCE
GIVEN THE REMARKABLE AGREEMENT BY THE LONG RANGE MODELS.
&&
.AVIATION.../06Z TAF ISSUANCE/
SIGNIFICANT SOUTHERN SHIFT ALONG WITH A BIT OF A SLOWING OCCURRED
WITH 00Z MODEL RUNS AND THIS PLACES ALL MPX TERMINALS WITHIN THE
HEART OF WHAT LOOKS TO BE AN IMPRESSIVE SNOW BAND...WITH 6-10 INCH
SNOW TOTALS /AND POSSIBLY MORE AT STC...MSP...RNH/ NOW EXPECTED. SFC
LOW RIGHT NOW IS CENTERED ALONG I-90 NEAR CHAMBERLAIN...SD. 00Z
NAM/GFS ALONG WITH THE RAP TRACK THIS LOW RIGHT DOWN I-90 THROUGH
THE DAY SUNDAY...PLACING THE MPX TERMINALS WITHIN THE HEAVIEST
SNOW. HAVE ALREADY BEEN GETTING SNOWFALL RATES OF AN INCH PLUS PER
HOUR IN WRN MN...SO CONTINUED TO ADVERTISE PROLONGED PERIODS OF
1/2SM VIS AT ALL TERMINALS...BUT TENDED TO SHIFT THAT MENTION OUT
IN TIME WITH THE SLOWING. ANOTHER ASPECT OF THE SLOWING WAS THE
NEED TO SLOW THE BACKING OF WINDS FROM THE EAST OVER TO THE
NW...ALONG WITH A TEMPERING OF SPEEDS SOME...AS NAM NOW SHOWING
GUST POTENTIAL GREATER THAN 35 KTS AT ONLY RWF. AS THIS TAF PERIOD
COMES TO AN END...CLEARING WILL START WORKING INTO WRN MN...WITH
VFR CONDITIONS EXPECTED AS WE START GOING A LITTLE BEYOND THIS TAF
PERIOD.
KMSP...ALL GUIDANCE NOW PUTTING MSP IN THE CROSS-HAIRS FOR THE
HEAVIEST SNOW WITH THIS EVENT...SO SIGNIFICANTLY DEGRADED
TAF...WITH LIFR VIS SNOW NOW EXTENDING WELL OUT INTO THE
AFTERNOON. LOOKING AT THE NAM ALONG WITH CURRENT RADAR...EXPECTING
TWO BURSTS OF SNOW THIS PERIOD. FIRST WILL COME BETWEEN 8Z AND 12Z
AS WARM ADVECTIVE WING OF PRECIP SWINGS THROUGH...WITH THE
NEXT...MORE PROLONGED BOUT OF HEAVY SNOW HITTING BETWEEN 14Z AND
22Z AS THE MAIN UPPER FORCING MOVES IN. THIS IS WHEN MAJORITY OF
ACCUMULATIONS SHOULD OCCUR...WITH SEVERAL OF THESE HOURS LIKELY
SEEING RATES AROUND 1 INCH AN HOUR. THIS TAF MAY A BIT PESSIMISTIC
WITH THE LENGTH OF 1/2SM VIS...BUT FEEL PRETTY CONFIDENT IN
WINDOWS OF HEAVIER SNOW THAT ARE INDICATED WITH TAF. AVIATION
WEATHER WARNING WILL ALSO BE ISSUED SHORTLY FOR ACCUMULATIONS
EXCEEDING 3/4 OF AN INCH PER HOUR. AS FOR STORM TOTAL...WOULD PUT
MSP ON THE HIGHER END OF THE SCALE WITH 8-10 INCHES LOOKING MORE
AND MORE LIKELY.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. WINDS SW AT 10G15KTS.
WED...VFR. WINDS SE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-RICE-STEELE-
WASECA.
WINTER STORM WARNING UNTIL 11 AM CST SUNDAY FOR CHIPPEWA-DOUGLAS-
KANDIYOHI-LAC QUI PARLE-POPE-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-
POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BENTON-
CHISAGO-ISANTI-KANABEC-MCLEOD-MEEKER-MILLE LACS-MORRISON-
SHERBURNE-STEARNS-TODD-WRIGHT.
WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR ANOKA-
CARVER-DAKOTA-HENNEPIN-RAMSEY-SCOTT-WASHINGTON.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR
MARTIN-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST SUNDAY FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BORGHOFF/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1117 PM CST SAT DEC 8 2012
.UPDATE...
ISSUED AT 849 PM CST SAT DEC 8 2012
MUCH OF THE CWA HAS BEEN DRY SO FAR THIS EVENING WITH LOW CLOUDS
AND SOME PATCHY FOG. STILL BELIEVE THAT RAIN CHANCES WILL INCREASE
SIGNIFICANTLY LATER THIS EVENING AND OVER NIGHT AS LARGE SCALE
ASCENT INCREASES AHEAD OF SHORTWAVE MOVING ACROSS THE CENTRAL
PLAINS. RAP HAS BEEN CONSISTENT IN SHOWING AN INCREASE IN LOW
LEVEL MOISTURE CONVERGENCE ALONG 850MB WARM FRONT TONIGHT. ONLY
CHANGE IN FORECAST IS TO REFLECT NEAR TERM PRECIPITATION AND
TEMPERATURE TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
(TONIGHT)
SHORTWAVE DIVING THROUGH EASTERN MONTANA AT THIS TIME IS FORCING
CYCLOGENESIS OVER THE NORTHERN PLAINS. SOUTHWESTERLY LOW LEVEL
FLOW WILL BEGIN TO INCREASE OVER THE LOWER MISSISSIPPI VALLEY
TONIGHT IN RESPONSE TO THE STRENGTHENING LOW. THIS WILL BRING THE
QUASI-STATIONARY FRONT HANGING OVER ARKANSAS BACK NORTH INTO OUR
AREA BY EARLY SUNDAY MORNING. LOW LEVEL JET RAMPS UP AROUND 30KTS
THIS EVENING PRODUCING DECENT 850MB MOISTURE CONVERGENCE OVER THE
AREA. AT FIRST IT`S RATHER WEAK AND DIFFUSE...BUT BECOMES STRONGER
OVER NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS LATE TONIGHT AS
THE 850MB TEMP GRADIENT TIGHTENS UP. EXPECT WIDELY SCATTERED
SHOWERS TO DEVELOP THIS EVENING OVER SOUTHEAST
MISSOURI...OVERSPREADING THE ENTIRE AREA AND INCREASING IN AREAL
COVERAGE IN RESPONSE TO THE INCREASING MOISTURE CONVERGENCE. COULD
SEE A LITTLE THUNDER AS WELL...PRIMARILY OVER SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS WHERE MUCAPE IS FORECAST TO EXCEED 250 J/KG.
TEMPERATURES WILL TAKE AN INITIAL DIP THIS EVENING...BUT SHOULD
LEVEL OUT AND POSSIBLY RISE SLIGHTLY AS THE WARM FRONT MOVES UP
INTO THE BI-STATE REGION LATE TONIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
SUNDAY AND SUNDAY NIGHT...
THE WARM FRONTAL BOUNDARY WILL BE LOCATED ACROSS THE SOUTHERN
PORTION OF THE CWA BY 12Z...WITH THE OVERNIGHT WARM ADVECTION
PRECIPITATION BEGINNING TO LIFT NORTH AND EAST OF THE CWA. THINK
THERE WILL BE A LULL IN THE RAIN BY MIDMORNING ACROSS A GOOD AMOUNT
OF THE CWA UNTIL A STRONG COLD FRONT MOVES SOUTHEAST ACROSS THE AREA
IN THE AFTERNOON AND EVENING. THIS FRONT WILL REINFORCE THE
BAROCLINICITY TO OUR SOUTHEAST AND LEAD TO LIGHT RAIN REDEVELOPING
ACROSS AT LEAST THE SOUTHEAST HALF OF THE CWA FOR THE AFTERNOON AND
EARLY EVENING HOURS. LUCKILY...ALL INDICATIONS ARE THAT THE RAIN
WILL TURN TO COLD SUNDAY NIGHT AS DEEP MOISTURE IS SHUNTED TO THE
SOUTHEAST AS THE WINTER BLAST ARRIVES AND COLD AIR DEEPENS ACROSS
THE CWA.
MONDAY THROUGH THURSDAY...
A RAW WINTER DAY IS ON TAP FOR MONDAY AS TEMPERATURES STRUGGLE TO
RISE BACK ABOVE FREEZING WITH STRONG COLD ADVECTION AND A GUSTY
NORTHWEST WIND. THE WINTER CHILL SHOULD BE BRIEF THOUGH...AS
TEMPERATURES WILL ALREADY BEGIN MODERATING BY MIDWEEK DESPITE A TROF
MOVING ACROSS THE MIDWEST. TEMPERATURES WILL RISE BACK ABOVE NORMAL
FOR THE END OF THE WEEK AS THE UPPER FLOW BECOMES SOUTHWEST IN
RESPONSE TO A STRONG STORM SYSTEM DIGGING SOUTH ALONG THE WEST COAST.
FRIDAY THROUGH SATURDAY...
NEARLY ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS A STRONG SHORTWAVE
AND SURFACE LOW PASSING TO THE WEST OF THE CWA FRIDAY NIGHT. THIS
PATTERN IS INDICATIVE OF ABOVE NORMAL TEMPERATURES AND A GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS.
CVKING
&&
.AVIATION...
ISSUED AT 1033 PM CST SAT DEC 8 2012
STRATUS CLOUDS WERE SLOWLY LOWERING THIS EVNG...EXCEPT AT UIN
WHERE RAIN DEVELOPED AND CAUSED THE CEILINGS TO TEMPORARILY RISE.
THE CEILING AT UIN SHOULD LOWER AGAIN LATE TGT BEFORE THE NEXT
ROUND OF RAIN MOVES IN. MORE LIGHT RAIN WILL DEVELOP LATE TGT AS
THE STATIONARY FRONT ACROSS NRN AR LIFTS BACK NWD INTO SRN MO AND
A SWLY LOW LEVEL JET BRINGS INCREASING AND DEEPENING LOW LEVEL
MOISTURE INTO THE AREA. CEILINGS WILL LIKELY LOWER TO 500 TO
1000 FT WITH VSBYS OF 2-4SM IN LIGHT RAIN AND FOG. E-SELY SFC
WIND WILL CONTINUE LATE TGT. THE RAIN SHOULD END IN UIN AND COU BY
LATE SUN MRNG AS A SFC WAVE ALONG THE FRONT MOVES E OF THE
AREA...WHILE A STRONG COLD FRONT DROPS SEWD INTO THE REGION. RAIN
WILL LIKELY CONTINUE IN THE ST LOUIS METRO AREA SUN AFTN UNTIL THE
COLD FRONT MOVES SE OF THE AREA WITH CAA AND DRYING OF THE LOW
LEVELS BEHIND THE COLD FRONT. THE SFC WIND WILL VEER AROUND TO A
NWLY DIRECTION AS THE SFC WAVE SHIFTS E OF THE AREA...AND THEN
STRENGTHENS AFTER PASSAGE OF THE STRONG COLD FRONT SUN AFTN. WILL
SEE AN IMPROVEMENT IN VSBYS LATE SUN MRNG AND AFTN...BUT ONLY A
VERY GRADUAL RISE IN CEILING HEIGHTS WITH CIGS RISING TO AROUND
1000 FT BY EARLY AFTN. THE CEILING WILL CONTINUE TO RISE...INTO
THE MVFR CATAGORY BY LATE AFTN AND TO THE VFR CATAGORY SUN EVNG.
SPECIFICS FOR KSTL...CIG HEIGHTS SHOULD CONTINUE TO LOWER LATE TGT
WITH FOG DEVELOPING. THE CIGS SHOULD LOWER TO AROUND 500-1000 FT
LATE TGT WITH VSBYS FALLING TO AROUND 2-4SM AS LIGHT RAIN MOVES
INTO THE AREA. AN E-SELY SFC WIND WILL CONTINUE LATE TGT AS A SFC
RIDGE SHIFTS WELL NE OF OUR AREA WHILE A WARM FRONT APPROACHES STL
FROM THE S. THE RAIN SHOULD END BY SUN EVNG AS A SFC WAVE ALONG
THIS FRONT SHIFTS WELL NE OF STL AND A STRONG COLD FRONT MOVES SE
OF STL CAUSING THE SFC WIND TO VEER AROUND TO A W-NWLY DIRECTION
AND STRENGTHEN DURING THE AFTN AND EVNG HOURS. THE VSBYS WILL
IMPROVE DURING THE LATE MRNG AND AFTN HOURS WITH THE CLOUD CEILING
RISING TO AROUND 1000 FT BY AFTN AND 1500 FT BY SUN EVNG. THE
CEILING SHOULD FINALY RISE INTO THE VFR CATAGORY LATE SUN NGT.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
826 PM MST MON DEC 10 2012
.SHORT TERM...VALID FOR TUE AND WED...
UPDATE TO ZFP AND WRKAFP. WILL CANCEL THE ADVISORY FOR THE NE BIG
HORNS WITH THIS PACKAGE. WATER VAPOR AND RAP MODEL SHOWED SEVERAL
SHORTWAVES MOVING S THROUGH THE REGION. GFS AND WRF HAD THE WAVES
MERGING INTO ONE BY 12Z TUE...THEN EXITING E OUT OF THE AREA AFTER
12Z. THE LEFT FRONT QUADRANT OF A PACIFIC JET WAS AIDING LIFT OVER
SW MT. BASED ON RADAR ECHOES AND MODEL CROSS-SECTIONS...IT
APPEARED THE SNOW WOULD BE LIGHT OVERNIGHT WARRANTING 20 TO 30
PERCENT POPS OVER THE PLAINS. WEB CAMS IN COOKE CITY SHOWED LIGHT
SNOW WITH SOME ACCUMULATION OCCURRING...SO KEPT LIKELY POPS
THROUGH 06Z THEN HAD CHANCE POPS OVERNIGHT AS THE FLOW ALOFT
TURNS ANTICYCLONIC. MODELS SHOWED MOISTURE DECREASING THROUGH THE
NIGHT OVER THE NE BIG HORNS SO ANY ADDITIONAL SNOW WILL BE LIGHT.
AS UPPER RIDGING BUILDS IN OVERNIGHT...LEE TROUGHING WILL DEEPEN
OVER THE AREA CREATING A FAVORABLE PRESSURE GRADIENT FOR ADVISORY
STRENGTH GAP WINDS. BUFKIT SOUNDINGS SUPPORTED STABLE LOW LAYERS
AS WELL. WINDS WILL BE DRIVEN BY MIXING BY LATE TUE MORNING
SUPPORTING CONTINUED GUSTY WINDS. NO CHANGES NEEDED TO WIND
ADVISORY.
MODELS SHOWED WARM ADVECTION OVERNIGHT. THE ADVECTION...CLOUD
COVER AND WINDS WILL KEEP TEMPERATURES FROM FALLING MUCH. HAVE
RAISED THE MINS OVER PORTIONS OF THE AREA.
TUE WILL BE WARMER UNDER THE UPPER RIDGE. WARM ADVECTION AND A
SHORTWAVE MAY BRING SOME PRECIPITATION TO EASTERN AREAS. ARTHUR
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MODELS CONTINUE TO ADVERTISE A SPLITTING UPPER TROF OVER THE AREA
THURSDAY AND FRIDAY. WITH ENERGY DIVING SOUTH OF THE AREA AND JET
ENERGY STUCK TO THE NORTH DON`T SEE MUCH OF AN IMPACT FROM THIS ON
WEATHER OVER SOUTHERN MONTANA/NORTHERN WYOMING OUTSIDE OF SOME
MOUNTAIN AND FOOTHILLS SHOWER ACTIVITY. WEST TO NORTHWEST FLOW
DEVELOPS BY SATURDAY INTO SUNDAY FOR DOWNSLOPING AND DRY
CONDITIONS. BY SUNDAY NIGHT A VIGOROUS WAVE DROPS SOUTHWARD ACROSS
WESTERN CANADA BUT KICKS EAST BEFORE MAKING IT INTO SOUTHERN
MONTANA. WILL HAVE TO WATCH THIS WAVE FOR ANY SOUTHWARD SHIFT BUT
FOR NOW LOOKS TO HAVE LITTLE IMPACT ON THE FORECAST AREA. MORE
RIDGING FORECAST MONDAY INTO WEDNESDAY FOR DRY AND WARM
CONDITIONS. TEMPERATURES LOOK TO HOLD IN THE 35 TO 45 DEGREE RANGE
FOR MOST OF THE EXTENDED PERIOD...WITH SOME HINTS OF LOWER 50S BY
THE END OF THE WEEKEND INTO EARLY NEXT WEEK. OVERALL ANY
SIGNIFICANT PRECIPITATION LOOKS TO STAY IN THE MOUNTAINS FOR THE
NEXT 7 TO 10 DAYS. CHAMBERS
&&
.AVIATION...
EXPECT PERIODS OF SNOW TO CONTINUE OVER AREA MOUNTAINS TONIGHT
WITH MOUNTAIN OBSCURATION PERSISTING INTO TUESDAY MORNING. ANOTHER
DISTURBANCE IS BRINGING MORE AREAS OF LIGHT SNOW ACROSS THE
REGION...RESULTING IN LOCALIZED MVFR TO IFR CONDITIONS. SNOW
SHOWERS SHOULD CLEAR FROM NORTH TO SOUTH AFTER MIDNIGHT...BUT MAY
LINGER IN AND AROUND KSHR UNTIL SUNRISE TUESDAY. WINDS ARE
EXPECTED TO INCREASE OVER THE WESTERN FOOTHILLS LATE
TONIGHT...WITH GUSTS TO 50 KNOTS BY MORNING AT KLVM...RESULTING IN
BLOWING AND DRIFTING SNOW FROM LIVINGSTON TO BIG TIMBER AND NYE.
LOW LEVEL WIND SHEAR WILL BE POSSIBLE AT KBIL THROUGH THE NIGHT
AND INTO TUESDAY. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 024/039 030/039 023/035 020/035 020/035 021/037 026/041
20/N 02/J 31/B 11/B 11/B 11/B 11/B
LVM 025/038 030/038 022/034 018/033 018/030 019/035 021/038
31/N 23/J 43/J 11/B 11/B 11/N 11/B
HDN 020/039 024/040 018/035 015/034 016/035 017/037 022/042
20/B 01/B 31/E 11/B 11/B 11/B 11/B
MLS 018/037 021/035 016/030 014/030 018/032 019/034 021/041
22/J 12/J 31/E 11/B 11/B 11/B 11/B
4BQ 019/037 020/038 018/034 016/033 017/034 018/036 021/042
22/J 01/B 21/E 11/B 11/B 11/B 11/B
BHK 015/035 020/035 015/029 013/028 016/030 019/032 020/040
22/J 12/J 21/E 11/B 11/B 11/B 11/B
SHR 014/037 020/038 017/036 014/032 013/033 014/034 016/038
20/B 01/B 21/B 11/B 11/B 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 10 AM MST
WEDNESDAY FOR ZONES 65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1120 PM CST SAT DEC 8 2012
.AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 06Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA THROUGH SUNDAY AFTERNOON. AT THE KLBF TERMINAL...EXPECT
CIGS AON 10000 FT AGL THROUGH 13Z SUNDAY MORNING...DROPPING DOWN TO
AROUND 3000 FT AGL. CIGS WILL BEGIN TO SCATTER OUT AFTER 22Z
SUNDAY...CLEARING OUT SUNDAY EVENING. AT THE KVTN TERMINAL...LIGHT
SNOW IS EXPECTED OVER THE NEXT 2 TO 4 HOURS...AND IS EXPECTED TO
EXIT THE TERMINAL AFTER 10Z SUNDAY. CIGS WILL REMAIN AON 1500 FT AGL
THROUGH SUNDAY MORNING...RISING TO 2500 FT AGL. SKIES WILL SCATTER
OUT SUNDAY AFTERNOON...CLEARING SUNDAY EVENING. STRONG NORTHERLY
WINDS OF 20 TO 25 KTS...WITH GUSTS UP TO 33 KTS ARE LIKELY FOR THE
REST OF TONIGHT THROUGH SUNDAY AFTERNOON. WINDS WILL QUICKLY
DIMINISH SUNDAY EVENING AFTER SUNDOWN.
&&
.PREV DISCUSSION... /ISSUED 1009 PM CST SAT DEC 8 2012/
UPDATE...BASED ON PRESSURE TRENDS ACROSS EASTERN SOUTH DAKOTA AND
THE LATEST NAM AND MAV GUIDANCE...DECIDED TO HOIST A WIND ADVISORY
FOR SUNDAY MORNING THROUGH SUNDAY AFTERNOON ACROSS A LARGE PORTION
OF NORTH CENTRAL AND CENTRAL NEBRASKA. STRONG PRESSURE RISES OF 3 TO
6 MB/3HR WILL TRACK FROM NORTH CENTRAL NEBRASKA INTO NORTHEASTERN
NEBRASKA FROM 12Z THROUGH 18Z SUNDAY. WINDS WILL PEAK AROUND NOON
TIME...THEN SLOWLY DECLINE INTO THE LATE AFTERNOON HOURS. IN
ADDITION TO STRONG WINDS...HIGHS SUNDAY WILL BE IN THE TEENS AND
20S...PRODUCING WIND CHILLS OF ZERO TO MINUS 10 IN THE ADVISORY
AREA. STILL WELL ABOVE CRITERIA FOR A WIND CHILL ADVISORY...BUT
WORTH MENTIONING IN THE HWO AND NPW/WIND ADVISORY PRODUCT. BULK OF
THE SNOW WILL REMAIN NORTH OF THE BORDER OVERNIGHT WITH ONLY A
DUSTING EXPECTED ALONG THE NEBR/SD BORDER.
&&
.PREV DISCUSSION... /ISSUED 606 PM CST SAT DEC 8 2012/
AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. AT THE KLBF TERMINAL...EXPECT CIGS AON 10000 FT AGL
THROUGH 10Z TONIGHT...DROPPING DOWN TO AROUND 4000 FT AGL. CIGS WILL
BEGIN TO SCATTER OUT AFTER 17Z SATURDAY. AT THE KVTN TERMINAL...CIGS
WILL DROP FROM 5000 FT AGL DOWN TO 1500 FT AGL OVERNIGHT AND REMAIN
THERE THROUGH MIDDAY SUNDAY. SKIES WILL BEGIN TO SCATTER OUT BY LATE
AFTERNOON. FOR BOTH TERMINALS...LOOK FOR NORTHERLY WINDS TO INCREASE
TO 15 TO 25 KTS TONIGHT WITH PERIODIC GUSTS TO AROUND 30 KTS AT BOTH
TERMINALS. WINDS WILL GRADUALLY DIMINISH LATE SUNDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SAT DEC 8 2012/
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY IN EFFECT FROM 4 AM
CST SUNDAY MORNING THROUGH 5 PM CST SUNDAY AFTERNOON FOR ZONES
NEZ005>010-025>029-037-038.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION AND UPDATE...BUTTLER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1009 PM CST SAT DEC 8 2012
.UPDATE...BASED ON PRESSURE TRENDS ACROSS EASTERN SOUTH DAKOTA AND
THE LATEST NAM AND MAV GUIDANCE...DECIDED TO HOIST A WIND ADVISORY
FOR SUNDAY MORNING THROUGH SUNDAY AFTERNOON ACROSS A LARGE PORTION
OF NORTH CENTRAL AND CENTRAL NEBRASKA. STRONG PRESSURE RISES OF 3 TO
6 MB/3HR WILL TRACK FROM NORTH CENTRAL NEBRASKA INTO NORTHEASTERN
NEBRASKA FROM 12Z THROUGH 18Z SUNDAY. WINDS WILL PEAK AROUND NOON
TIME...THEN SLOWLY DECLINE INTO THE LATE AFTERNOON HOURS. IN
ADDITION TO STRONG WINDS...HIGHS SUNDAY WILL BE IN THE TEENS AND
20S...PRODUCING WIND CHILLS OF ZERO TO MINUS 10 IN THE ADVISORY
AREA. STILL WELL ABOVE CRITERIA FOR A WIND CHILL ADVISORY...BUT
WORTH MENTIONING IN THE HWO AND NPW/WIND ADVISORY PRODUCT. BULK OF
THE SNOW WILL REMAIN NORTH OF THE BORDER OVERNIGHT WITH ONLY A
DUSTING EXPECTED ALONG THE NEBR/SD BORDER.
&&
.PREV DISCUSSION... /ISSUED 606 PM CST SAT DEC 8 2012/
AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. AT THE KLBF TERMINAL...EXPECT CIGS AON 10000 FT AGL
THROUGH 10Z TONIGHT...DROPPING DOWN TO AROUND 4000 FT AGL. CIGS WILL
BEGIN TO SCATTER OUT AFTER 17Z SATURDAY. AT THE KVTN TERMINAL...CIGS
WILL DROP FROM 5000 FT AGL DOWN TO 1500 FT AGL OVERNIGHT AND REMAIN
THERE THROUGH MIDDAY SUNDAY. SKIES WILL BEGIN TO SCATTER OUT BY LATE
AFTERNOON. FOR BOTH TERMINALS...LOOK FOR NORTHERLY WINDS TO INCREASE
TO 15 TO 25 KTS TONIGHT WITH PERIODIC GUSTS TO AROUND 30 KTS AT BOTH
TERMINALS. WINDS WILL GRADUALLY DIMINISH LATE SUNDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SAT DEC 8 2012/
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY IN EFFECT FROM 4 AM
CST SUNDAY MORNING THROUGH 5 PM CST SUNDAY AFTERNOON FOR ZONES
NEZ005>010-025>029-037-038.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION AND UPDATE...BUTTLER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
928 PM EST MON DEC 10 2012
.SYNOPSIS...
WIDESPREAD LIGHT RAIN WILL MIX WITH AND CHANGE TO LIGHT SNOW LATER
THIS EVENING BEFORE TAPERING OFF OVERNIGHT. A FEW INCHES ARE
POSSIBLE...MAINLY OVER THE HIGHER TERRAIN OF THE NORTHERN MOUNTAINS.
SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN EXPECTED FROM
TUESDAY ONWARD INTO NEXT WEEKEND AS HIGH PRESSURE DOMINATES
REGIONAL WEATHER CONDITIONS. SEASONABLY COLD TEMPERATURES TUESDAY
INTO WEDNESDAY...WILL MODERATE BY LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 919 PM EST MONDAY...SFC OBS INDICATE SLK/WNK AND LKP ACRS
THE DACKS HAVE CHANGED TO SNOW WITH TEMPS NEAR FREEZING ATTM. LLVL
CAA CONTS FROM NW TO SE ACRS OUR CWA THIS EVENING WITH WHITEFACE
AT NEAR 85H DOWN TO 23F. LITTLE SNOW ACCUMULATION HAS BEEN
OBSERVED SO FAR VIA WEB CAMS OR SPOTTER REPORTS. IN
ADDITION...DRIER AIR CONTS TO ALSO ADVECT INTO OUR CWA THIS
EVENING ON NW TO NORTH WINDS BEHIND THE SFC BOUNDARIES. THIS HAS
RESULTED IN A DECREASE IN AREAL COVERAGE/INTENSITY OF PRECIP ACRS
NORTHERN NY AS EXPECTED...WITH MOST OF THE SLV DRY ATTM. HAVE
DECREASED POPS ACRS THE SLV THRU THE REST OF TONIGHT BASED ON
RADAR TRENDS. ELSEWHERE...1000 TO 700MB RH CONTS THRU 05Z ACRS THE
DACKS AND UNTIL 09Z FOR MOST OF CENTRAL/NORTHERN VT
MTNS...SUPPORTING SOME LIGHT SNOWFALL. IN ADDITION...SOME BLOCKED
FLW AND ADDITIONAL LAKE CHAMPLAIN MOISTURE INTERACTION WL HELP TO
KEEP SNOW ACTIVITY GOING A BIT LONGER ACRS THE WESTERN
SLOPES/EASTERN CPV EARLY TUESDAY MORNING. STILL THINKING A DUSTING
TO A COUPLE OF INCHES WITH SOME ISOLATED AREAS ALONG THE WESTERN
SLOPE GETTING 3 INCHES OR SO BY MORNING. LITTLE SNOW ACCUMULATION
IS EXPECTED ON THE WESTERN SIDE OF THE CPV AND CT RIVER VALLEY.
WITH A DUSTING TO 2 INCHES POSSIBLE FOR THE MTNS OF THE NEK BY
TUES AM. TEMPS WL BE TRICKY WITH SHARP NW TO SE THERMAL GRADIENT
ASSOCIATED WITH CAA ACRS OUR CWA. THINKING MID TEEN SLV/SLK TO
L/M30S VSF. AS TEMPS SLOWLY DROP BLW FREEZING AREAS OF PATCHY
BLACK ICE WL BE POSSIBLE AND COULD CREATE A FEW SLICK SPOTS DURING
THE MORNING COMMUTE.
OVERALL FCST IN GOOD SHAPE WITH ONLY SOME MINOR ADJUSTMENTS BASED
ON CRNT TRENDS. LATEST SFC ANALYSIS PLACES LOW PRES NORTH OF THE
BORDER WITH ONE COLD FRNT ACRS THE CPV ATTM...AND ANOTHER ONE
APPROACHING THE SLV...WITH MUCH COLDER AIR BEHIND THIS FRNT. THE
FIRST FRNT HAS RESULTED IN AN OVERALL INCREASE IN AREAL
COVERAGE/INTENSITY OF RAIN SHOWERS ACRS THE CPV AND PARTS OF
CENTRAL/NORTHERN VT THIS EVENING...WITH ADDITIONAL SHOWERS ACRS
NORTHERN NY. WL CONT TO MENTION POPS AT 100% THRU 00Z...THEN START
TO TAPER POPS OFF FROM THE SLV EASTWARD. WHITEFACE OBS DOWN TO
28F...WHICH INDICATES THE COLDER AIR IS MOVING IN ALOFT...BUT SFC
TEMPS STILL REMAIN ABOVE 0C ACRS OUR CWA...WHICH WL MAKE RAIN TO
SNOW AND AMOUNT OF ACCUMULATION DIFFICULT TONIGHT. BASED ON OBS
AND LATEST RAP MODEL...THINKING CHANGE OVER TO SNOW WL OCCUR AT
SLK BTWN 01Z-02Z...MPV/BTV BY 05Z...AND ACRS EASTERN/SOUTHERN VT
AFT 06Z. NEXT QUESTION WL BE AMOUNT OF RH LEFTOVER...WHICH RAP/NAM
SHOW QUICKLY DISSIPATING AS THERMAL PROFILES BECM COLD ENOUGH FOR
SNOW. THINKING THE COMBINATION OF UPSLOPE FLW...SOME 1000 TO 700MB
RH...AND FAVORABLE BLOCKING/CONVERGENCE ACRS THE CPV...WL RESULT
IN A PERIOD OF SNOW SHOWERS WITH SOME ACCUMULATIONS...WHICH CRNT
FCST HAS COVERED NICELY. THINKING DUSTING TO AN INCH
BTV/PBG...AROUND 2" FOR ESSEX/JERICHO...AND UP TO 3" POSSIBLE NEAR
UNDERHILL/STOWE/JAY PEAK BY 12Z TUES AND A DUSTING TO SEVERAL
INCHES FOR THE DACKS...AND ONLY LIGHT AMOUNTS CT RIVER VALLEY AND
SLV. WL CONT TO MONITOR CRNT TRENDS FOR POTENTIAL
ADJUSTMENTS...BUT OVERALL FCST IN GOOD SHAPE.
FORECAST REMAINS ON TRACK FOR TONIGHT WITH NEAR TERM CHALLENGES
BEING THE OVERALL COVERAGE OF PCPN...AND THE EXTENT TO WHICH
COOLING NEAR-SFC THERMAL PROFILES OVERNIGHT LEAD TO MINOR SNOWFALL
ACCUMULATIONS. PARENT LOW PRESSURE SYSTEM RESPONSIBLE FOR THIS
AFTERNOON`S RAIN/SHOWERS CURRENTLY PASSING NORTHEAST THROUGH THE
SLV NEAR MONTREAL AND EXPECT THIS TREND TO CONTINUE TONIGHT. A
GENERAL REBLOSSOMING OF RAINFALL IS NOW OCCURRING ACROSS THE
REGION ASSOCIATED WITH WEAK SFC WAVE RIDING NORTHEAST ALONG LEAD
FRONTAL BOUNDARY FROM CENTRAL PA INTO CENTRAL/WRN NY STATE UP TO
THE PARENT LOW. AN ADDITIONAL 0.15 TO 0.25 INCHES OR SO IS
EXPECTED WITH THIS ACTIVITY THROUGH THE 00-02Z TIME FRAME AS THE
FRONT SWINGS THROUGH THE REGION. TEMPERATURES QUITE MILD THROUGH
EARLY EVENING...NOTED BY MANY READINGS IN THE 40S AND INTO LOWER
AND MID 50S IN SOME CASES AS OF 3 PM.
OF ADDITIONAL INTEREST IS THE PRIMARY POLAR FRONT STILL STATIONARY
FURTHER OFF TO THE NORTHWEST BEHIND THE LEADING FRONT. MUCH COLDER
AIR BACK BEHIND THIS SECONDARY BOUNDARY AND AS AFOREMENTIONED SFC
LOW SWINGS AWAY TO THE NORTHEAST...THIS FRONT WILL SURGE SOUTHEAST
AND OVERTAKE THE LEAD FRONT LATER THIS EVENING. FLOW TRENDS
NORTHWEST BEHIND THIS PASSAGE WITH STRONG CAA SETTING UP AS 925-850
MB THERMAL PROFILES CRASH AFTER MIDNIGHT. ALL RELIABLE MODELS SHOW
AT LEAST SOME CHANGEOVER TO SNOW DURING A 3-6 HOUR PERIOD FROM ABOUT
02Z-07Z AS THIS OCCURS AND BACK EDGE OF PCPN EXITS TO THE EAST. LOW
FROUDE NUMBER PROFILES SUPPORT AMPLE LOW LEVEL BLOCKING FAVORING THE
WESTERN SLOPES AS MEAN PBL WINDFLOW TRENDS NORTHWEST. HOWEVER...
PROBLEMATIC ISSUES ON POTENTIAL ACCUMULATIONS EXIST AS USUAL...AND
MAINLY CONCERN A NARROWING COLUMNAR MOISTURE DEPTH OVER TIME AND HOW
QUICKLY THE NEAR-SFC 2M TEMPERATURES CAN COOL AS EVIDENCED BY 12Z
3-HRLY MOS NUMBERS. AFTER USING SEVERAL METHODS...MY BEST ESTIMATE
IS FOR ONLY VERY LIGHT ACCUMULATIONS TO OCCUR IN THE LOWER
ELEVATIONS...SAY A DUSTING TO PERHAPS AN INCH...WITH A GENERAL 1-3
INCH ACCUMULATION EXPECTED ABOVE 1 KFT AND PERHAPS 3-5" NEAR THE
SUMMIT LEVEL. TEMPERATURES TO HOLD MILD THROUGH EARLY...THAN FALL
RATHER SHARPLY LATER TONIGHT BOTTOMING OUT FROM THE UPPER TEENS TO
MID 20S NORTH AND WEST...AND UPPER 20S/LOWER 30S SOUTH/SOUTHEAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 317 PM EST MONDAY...REMAINDER OF THE SHORT TERM THEN TRENDS
RELATIVELY QUITE AS CANADIAN HIGH PRESSURE SETTLES ATOP THE
REGION. OTHER THAN SOME LINGERING NRN MTN FLURRIES IN THE
MORNING...EXPECTING A CHILLY DAY ON TAP FOR TOMORROW (TUESDAY) AS
925 MB TEMPERATURES CONTINUE TO FALL INTO THE -8C TO -12C RANGE BY
MID-AFTERNOON UNDER MODEST NORTHWESTERLY GRADIENT. THIS SUPPORTS
HIGHS HOLDING MAINLY STEADY IN THE 20S FOR MOST LOCALES...THOUGH A
FEW LOWER 30S POSSIBLE IN FAVORED DOWNSLOPE REGIONS OF SOUTHERN
VT.
THEREAFTER...CLEAR TO PTLY CLOUDY SKIES CONTINUE TUESDAY NIGHT INTO
WEDNESDAY NIGHT WITH AFOREMENTIONED HIGH SLIDING SLOWLY ATOP AND
EAST OF THE REGION. AFTER A CHILLY NIGHT TUESDAY NIGHT IN THE
SINGLE DIGITS TO TEENS...READINGS TO REBOUND BACK TO NEAR SEASONAL
NORMS BY WEDNESDAY AS MODEST SOUTHWESTERLY RETURN FLOW DEVELOPS. AS
MENTIONED EARLIER...MAINLY DRY WEATHER EXPECTED DURING THESE
PERIODS...THOUGH I HAVE HINTED AT A FEW FLURRIES ACROSS THE
SLV/DACKS TO ACCT FOR ANY WEAK LAKE ENHANCED ACTIVITY THAT HI-RES
MODELS SUGGEST MAY BE DRIFTING AROUND.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 317 PM EST MONDAY...FIRST HALF OF THE EXTENDED PERIOD WILL
CONTINUE TO FEATURE RATHER QUIET WEATHER THANKS TO HIGH PRESSURE
RIDGING. THINGS GET MORE INTERESTING FOR LATER IN THE WEEKEND AND
EARLY NEXT WEEK WHEN IT APPEARS A MORE UNSETTLED PATTERN WILL SET
UP. UNFORTUNATELY, THE SPREAD IN GUIDANCE IS RATHER LARGE BY THIS
POINT, SO ALTHOUGH CONFIDENCE IS MODERATE/HIGH FOR THURSDAY AND
FRIDAY, IT`S LOW/VERY LOW BY SUNDAY & MONDAY. DAILY SPECIFICS
BELOW:
THURSDAY & FRIDAY: LOW/MID LEVEL RIDGE WILL PERSIST, RESULTING IN A
COUPLE OF DRY AND FAIRLY SUNNY DAYS. TEMPERATURES WILL BE SLIGHTLY
ABOVE NORMAL BOTH DAYS -- LOTS OF 30S THURSDAY AND 30S AND 40S
(LOWER ELEVATIONS) FOR FRIDAY AS 925MB TEMPERATURES CLIMB TO -2C TO
0C RANGE. STUCK CLOSE TO GUIDANCE FOR HIGH AND LOW TEMPERATURES.
SATURDAY: 12Z GFS AND EURO RUNS START TO DIVERGE AT THIS POINT. GFS
INDICATES A VERY WEAK UPPER TROF AND ASSOCIATED WEAK SURFACE LOW
WILL ZIP BY TO OUR NORTH, PERHAPS PRODUCING A FEW MOUNTAIN
FLURRIES. EURO IS EVEN WEAKER WITH THE FEATURE. SHOULD END OUT TO BE
ANOTHER DRY DAY OVERALL, BUT A LITTLE COOLER THAN FRIDAY AS THE MEAN
FLOW SHIFTS MORE WEST/NORTHWEST. AGAIN, STAYED CLOSE TO GUIDANCE FOR
TEMPERATURES.
SUNDAY: MODELS FOR SEVERAL RUNS HAVE BEEN SHOWING SOME SORT OF UPPER
TROF DIGGING TO OUR WEST, WHILE SURFACE LOW PRESSURE PUSHES OUT OF
THE GREAT LAKES AND TOWARD THE COAST. ALL RUNS HAVE BEEN DIFFERENT
IN THE DETAILS. EURO HAS BEEN MORE PROGRESSIVE AND FASTER WITH THIS,
AND THE 12Z EURO IS NO DIFFERENT -- WOULD SUGGEST LOTS OF CLOUDS AND
LIGHT PRECIPITATION BREAKING OUT SUNDAY MORNING. GFS HOLDS BACK A
MORE CUT-OFF LOW FARTHER TO THE SOUTHWEST, KEEPING THE DAY HERE
DRY, AND ONLY SKIMMING THE SOUTHERN HALF OF THE REGION WITH LIGHT
PRECIPITATION SUNDAY NIGHT AS IT SLIDES THE LOW SOUTH OF NEW ENGLAND.
GIVEN OVERALL TRACK RECORD OF EURO AND HPC`S FAVORING THAT MODEL,
HAVE PAINTED IN CHANCE LEVEL POPS FOR SUNDAY. MODEL PROFILES SUGGEST
THAT THERE COULD BE SOME MIXED PRECIPITATION, BUT THIS FAR OUT I
KEPT IT TO A SIMPLE RAIN/SNOW OPTION. TEMPERATURES -- STUCK A BIT
CLOSER TO THE EURO WHICH FEATURES MOST AREAS REACHING THE 35-40F
RANGE. GOOD DEAL OF BUST POTENTIAL HERE.
MONDAY: MODELS ARE ALL OVER THE PLACE, THOUGH ALL FEATURE SOME SORT
OF STRENGTHENING LOW PRESSURE -- WHETHER FAR SOUTHEAST OF NEW
ENGLAND (12Z GFS), EAST OF MAINE (00Z EURO), OR OVER THE
MID-ATLANTIC (12Z EURO). AT THIS POINT, BEST COURSE IS TO HAVE AT
LEAST CHANCE LEVEL POPS PAINTED IN ACROSS THE ENTIRE REGION. THE
12Z EURO TAKEN AT FACE VALUE WOULD SUGGEST A WET/WINDY/WARM STORM.
FOR TEMPERATURES, STARTED WITH THE EURO, BUT TOOK SEVERAL DEGREES
OFF. STILL ENDED UP WITH A LOT OF 40S FOR HIGHS.
I SUSPECT THE FORECASTS FOR THE WEEKEND AND EARLY NEXT WEEK ARE
GOING TO CHANGE QUITE A BIT BETWEEN NOW AND THEN...
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...LOTS OF MVFR AND IFR CEILINGS ACROSS THE
REGION THIS EVENING...AND DON`T EXPECT MUCH CHANGE FOR TONIGHT.
A COLD FRONT WILL PUSH ACROSS THE REGION FROM WEST TO EAST BETWEEN
00Z-06Z...WITH WEST WINDS SHIFTING INTO THE NORTHWEST. WIDESPREAD
RAIN SHOWERS THIS EVENING WILL TRANSITION TO SNOW SHOWERS
OVERNIGHT...WITH A FEW HOURS OF LIGHT SNOW/SNOW SHOWER ACTIVITY
AT ALL TERMINAL LOCATIONS. CEILINGS AND VISIBILITIES WILL LIKELY
BE REDUCED BRIEFLY TO IFR LEVELS. CONDITIONS WILL IMPROVE TUESDAY
MORNING WITH CEILINGS LIFTING TO VFR LEVELS...THOUGH MPV AND SLK
MAY STILL HANG ONTO MVFR UNTIL AROUND 16Z.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...PRETTY MUCH VFR THE
ENTIRE TIME THANKS TO HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...NASH
AVIATION...RJS/NASH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
720 PM EST MON DEC 10 2012
.SYNOPSIS...
WIDESPREAD LIGHT RAIN WILL MIX WITH AND CHANGE TO LIGHT SNOW LATER
THIS EVENING BEFORE TAPERING OFF OVERNIGHT. A FEW INCHES ARE
POSSIBLE...MAINLY OVER THE HIGHER TERRAIN OF THE NORTHERN MOUNTAINS.
SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN EXPECTED FROM
TUESDAY ONWARD INTO NEXT WEEKEND AS HIGH PRESSURE DOMINATES
REGIONAL WEATHER CONDITIONS. SEASONABLY COLD TEMPERATURES TUESDAY
INTO WEDNESDAY...WILL MODERATE BY LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 632 PM EST MONDAY...OVERALL FCST IN GOOD SHAPE WITH ONLY SOME
MINOR ADJUSTMENTS BASED ON CRNT TRENDS. LATEST SFC ANALYSIS PLACES
LOW PRES NORTH OF THE BORDER WITH ONE COLD FRNT ACRS THE CPV
ATTM...AND ANOTHER ONE APPROACHING THE SLV...WITH MUCH COLDER AIR
BEHIND THIS FRNT. THE FIRST FRNT HAS RESULTED IN AN OVERALL
INCREASE IN AREAL COVERAGE/INTENSITY OF RAIN SHOWERS ACRS THE CPV
AND PARTS OF CENTRAL/NORTHERN VT THIS EVENING...WITH ADDITIONAL
SHOWERS ACRS NORTHERN NY. WL CONT TO MENTION POPS AT 100% THRU
00Z...THEN START TO TAPER POPS OFF FROM THE SLV EASTWARD.
WHITEFACE OBS DOWN TO 28F...WHICH INDICATES THE COLDER AIR IS
MOVING IN ALOFT...BUT SFC TEMPS STILL REMAIN ABOVE 0C ACRS OUR
CWA...WHICH WL MAKE RAIN TO SNOW AND AMOUNT OF ACCUMULATION
DIFFICULT TONIGHT. BASED ON OBS AND LATEST RAP MODEL...THINKING
CHANGE OVER TO SNOW WL OCCUR AT SLK BTWN 01Z-02Z...MPV/BTV BY
05Z...AND ACRS EASTERN/SOUTHERN VT AFT 06Z. NEXT QUESTION WL BE
AMOUNT OF RH LEFTOVER...WHICH RAP/NAM SHOW QUICKLY DISSIPATING AS
THERMAL PROFILES BECM COLD ENOUGH FOR SNOW. THINKING THE
COMBINATION OF UPSLOPE FLW...SOME 1000 TO 700MB RH...AND FAVORABLE
BLOCKING/CONVERGENCE ACRS THE CPV...WL RESULT IN A PERIOD OF SNOW
SHOWERS WITH SOME ACCUMULATIONS...WHICH CRNT FCST HAS COVERED
NICELY. THINKING DUSTING TO AN INCH BTV/PBG...AROUND 2" FOR
ESSEX/JERICHO...AND UP TO 3" POSSIBLE NEAR UNDERHILL/STOWE/JAY
PEAK BY 12Z TUES AND A DUSTING TO SEVERAL INCHES FOR THE
DACKS...AND ONLY LIGHT AMOUNTS CT RIVER VALLEY AND SLV. WL CONT TO
MONITOR CRNT TRENDS FOR POTENTIAL ADJUSTMENTS...BUT OVERALL FCST
IN GOOD SHAPE.
FORECAST REMAINS ON TRACK FOR TONIGHT WITH NEAR TERM CHALLENGES
BEING THE OVERALL COVERAGE OF PCPN...AND THE EXTENT TO WHICH
COOLING NEAR-SFC THERMAL PROFILES OVERNIGHT LEAD TO MINOR SNOWFALL
ACCUMULATIONS. PARENT LOW PRESSURE SYSTEM RESPONSIBLE FOR THIS
AFTERNOON`S RAIN/SHOWERS CURRENTLY PASSING NORTHEAST THROUGH THE
SLV NEAR MONTREAL AND EXPECT THIS TREND TO CONTINUE TONIGHT. A
GENERAL REBLOSSOMING OF RAINFALL IS NOW OCCURRING ACROSS THE
REGION ASSOCIATED WITH WEAK SFC WAVE RIDING NORTHEAST ALONG LEAD
FRONTAL BOUNDARY FROM CENTRAL PA INTO CENTRAL/WRN NY STATE UP TO
THE PARENT LOW. AN ADDITIONAL 0.15 TO 0.25 INCHES OR SO IS
EXPECTED WITH THIS ACTIVITY THROUGH THE 00-02Z TIME FRAME AS THE
FRONT SWINGS THROUGH THE REGION. TEMPERATURES QUITE MILD THROUGH
EARLY EVENING...NOTED BY MANY READINGS IN THE 40S AND INTO LOWER
AND MID 50S IN SOME CASES AS OF 3 PM.
OF ADDITIONAL INTEREST IS THE PRIMARY POLAR FRONT STILL STATIONARY
FURTHER OFF TO THE NORTHWEST BEHIND THE LEADING FRONT. MUCH COLDER
AIR BACK BEHIND THIS SECONDARY BOUNDARY AND AS AFOREMENTIONED SFC
LOW SWINGS AWAY TO THE NORTHEAST...THIS FRONT WILL SURGE SOUTHEAST
AND OVERTAKE THE LEAD FRONT LATER THIS EVENING. FLOW TRENDS
NORTHWEST BEHIND THIS PASSAGE WITH STRONG CAA SETTING UP AS 925-850
MB THERMAL PROFILES CRASH AFTER MIDNIGHT. ALL RELIABLE MODELS SHOW
AT LEAST SOME CHANGEOVER TO SNOW DURING A 3-6 HOUR PERIOD FROM ABOUT
02Z-07Z AS THIS OCCURS AND BACK EDGE OF PCPN EXITS TO THE EAST. LOW
FROUDE NUMBER PROFILES SUPPORT AMPLE LOW LEVEL BLOCKING FAVORING THE
WESTERN SLOPES AS MEAN PBL WINDFLOW TRENDS NORTHWEST. HOWEVER...
PROBLEMATIC ISSUES ON POTENTIAL ACCUMULATIONS EXIST AS USUAL...AND
MAINLY CONCERN A NARROWING COLUMNAR MOISTURE DEPTH OVER TIME AND HOW
QUICKLY THE NEAR-SFC 2M TEMPERATURES CAN COOL AS EVIDENCED BY 12Z
3-HRLY MOS NUMBERS. AFTER USING SEVERAL METHODS...MY BEST ESTIMATE
IS FOR ONLY VERY LIGHT ACCUMULATIONS TO OCCUR IN THE LOWER
ELEVATIONS...SAY A DUSTING TO PERHAPS AN INCH...WITH A GENERAL 1-3
INCH ACCUMULATION EXPECTED ABOVE 1 KFT AND PERHAPS 3-5" NEAR THE
SUMMIT LEVEL. TEMPERATURES TO HOLD MILD THROUGH EARLY...THAN FALL
RATHER SHARPLY LATER TONIGHT BOTTOMING OUT FROM THE UPPER TEENS TO
MID 20S NORTH AND WEST...AND UPPER 20S/LOWER 30S SOUTH/SOUTHEAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 317 PM EST MONDAY...REMAINDER OF THE SHORT TERM THEN TRENDS
RELATIVELY QUITE AS CANADIAN HIGH PRESSURE SETTLES ATOP THE
REGION. OTHER THAN SOME LINGERING NRN MTN FLURRIES IN THE
MORNING...EXPECTING A CHILLY DAY ON TAP FOR TOMORROW (TUESDAY) AS
925 MB TEMPERATURES CONTINUE TO FALL INTO THE -8C TO -12C RANGE BY
MID-AFTERNOON UNDER MODEST NORTHWESTERLY GRADIENT. THIS SUPPORTS
HIGHS HOLDING MAINLY STEADY IN THE 20S FOR MOST LOCALES...THOUGH A
FEW LOWER 30S POSSIBLE IN FAVORED DOWNSLOPE REGIONS OF SOUTHERN
VT.
THEREAFTER...CLEAR TO PTLY CLOUDY SKIES CONTINUE TUESDAY NIGHT INTO
WEDNESDAY NIGHT WITH AFOREMENTIONED HIGH SLIDING SLOWLY ATOP AND
EAST OF THE REGION. AFTER A CHILLY NIGHT TUESDAY NIGHT IN THE
SINGLE DIGITS TO TEENS...READINGS TO REBOUND BACK TO NEAR SEASONAL
NORMS BY WEDNESDAY AS MODEST SOUTHWESTERLY RETURN FLOW DEVELOPS. AS
MENTIONED EARLIER...MAINLY DRY WEATHER EXPECTED DURING THESE
PERIODS...THOUGH I HAVE HINTED AT A FEW FLURRIES ACROSS THE
SLV/DACKS TO ACCT FOR ANY WEAK LAKE ENHANCED ACTIVITY THAT HI-RES
MODELS SUGGEST MAY BE DRIFTING AROUND.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 317 PM EST MONDAY...FIRST HALF OF THE EXTENDED PERIOD WILL
CONTINUE TO FEATURE RATHER QUIET WEATHER THANKS TO HIGH PRESSURE
RIDGING. THINGS GET MORE INTERESTING FOR LATER IN THE WEEKEND AND
EARLY NEXT WEEK WHEN IT APPEARS A MORE UNSETTLED PATTERN WILL SET
UP. UNFORTUNATELY, THE SPREAD IN GUIDANCE IS RATHER LARGE BY THIS
POINT, SO ALTHOUGH CONFIDENCE IS MODERATE/HIGH FOR THURSDAY AND
FRIDAY, IT`S LOW/VERY LOW BY SUNDAY & MONDAY. DAILY SPECIFICS
BELOW:
THURSDAY & FRIDAY: LOW/MID LEVEL RIDGE WILL PERSIST, RESULTING IN A
COUPLE OF DRY AND FAIRLY SUNNY DAYS. TEMPERATURES WILL BE SLIGHTLY
ABOVE NORMAL BOTH DAYS -- LOTS OF 30S THURSDAY AND 30S AND 40S
(LOWER ELEVATIONS) FOR FRIDAY AS 925MB TEMPERATURES CLIMB TO -2C TO
0C RANGE. STUCK CLOSE TO GUIDANCE FOR HIGH AND LOW TEMPERATURES.
SATURDAY: 12Z GFS AND EURO RUNS START TO DIVERGE AT THIS POINT. GFS
INDICATES A VERY WEAK UPPER TROF AND ASSOCIATED WEAK SURFACE LOW
WILL ZIP BY TO OUR NORTH, PERHAPS PRODUCING A FEW MOUNTAIN
FLURRIES. EURO IS EVEN WEAKER WITH THE FEATURE. SHOULD END OUT TO BE
ANOTHER DRY DAY OVERALL, BUT A LITTLE COOLER THAN FRIDAY AS THE MEAN
FLOW SHIFTS MORE WEST/NORTHWEST. AGAIN, STAYED CLOSE TO GUIDANCE FOR
TEMPERATURES.
SUNDAY: MODELS FOR SEVERAL RUNS HAVE BEEN SHOWING SOME SORT OF UPPER
TROF DIGGING TO OUR WEST, WHILE SURFACE LOW PRESSURE PUSHES OUT OF
THE GREAT LAKES AND TOWARD THE COAST. ALL RUNS HAVE BEEN DIFFERENT
IN THE DETAILS. EURO HAS BEEN MORE PROGRESSIVE AND FASTER WITH THIS,
AND THE 12Z EURO IS NO DIFFERENT -- WOULD SUGGEST LOTS OF CLOUDS AND
LIGHT PRECIPITATION BREAKING OUT SUNDAY MORNING. GFS HOLDS BACK A
MORE CUT-OFF LOW FARTHER TO THE SOUTHWEST, KEEPING THE DAY HERE
DRY, AND ONLY SKIMMING THE SOUTHERN HALF OF THE REGION WITH LIGHT
PRECIPITATION SUNDAY NIGHT AS IT SLIDES THE LOW SOUTH OF NEW ENGLAND.
GIVEN OVERALL TRACK RECORD OF EURO AND HPC`S FAVORING THAT MODEL,
HAVE PAINTED IN CHANCE LEVEL POPS FOR SUNDAY. MODEL PROFILES SUGGEST
THAT THERE COULD BE SOME MIXED PRECIPITATION, BUT THIS FAR OUT I
KEPT IT TO A SIMPLE RAIN/SNOW OPTION. TEMPERATURES -- STUCK A BIT
CLOSER TO THE EURO WHICH FEATURES MOST AREAS REACHING THE 35-40F
RANGE. GOOD DEAL OF BUST POTENTIAL HERE.
MONDAY: MODELS ARE ALL OVER THE PLACE, THOUGH ALL FEATURE SOME SORT
OF STRENGTHENING LOW PRESSURE -- WHETHER FAR SOUTHEAST OF NEW
ENGLAND (12Z GFS), EAST OF MAINE (00Z EURO), OR OVER THE
MID-ATLANTIC (12Z EURO). AT THIS POINT, BEST COURSE IS TO HAVE AT
LEAST CHANCE LEVEL POPS PAINTED IN ACROSS THE ENTIRE REGION. THE
12Z EURO TAKEN AT FACE VALUE WOULD SUGGEST A WET/WINDY/WARM STORM.
FOR TEMPERATURES, STARTED WITH THE EURO, BUT TOOK SEVERAL DEGREES
OFF. STILL ENDED UP WITH A LOT OF 40S FOR HIGHS.
I SUSPECT THE FORECASTS FOR THE WEEKEND AND EARLY NEXT WEEK ARE
GOING TO CHANGE QUITE A BIT BETWEEN NOW AND THEN...
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...LOTS OF MVFR AND IFR CEILINGS ACROSS THE
REGION THIS EVENING...AND DON`T EXPECT MUCH CHANGE FOR TONIGHT.
A COLD FRONT WILL PUSH ACROSS THE REGION FROM WEST TO EAST BETWEEN
00Z-06Z...WITH WEST WINDS SHIFTING INTO THE NORTHWEST. WIDESPREAD
RAIN SHOWERS THIS EVENING WILL TRANSITION TO SNOW SHOWERS
OVERNIGHT...WITH A FEW HOURS OF LIGHT SNOW/SNOW SHOWER ACTIVITY
AT ALL TERMINAL LOCATIONS. CEILINGS AND VISIBILITIES WILL LIKELY
BE REDUCED BRIEFLY TO IFR LEVELS. CONDITIONS WILL IMPROVE TUESDAY
MORNING WITH CEILINGS LIFTING TO VFR LEVELS...THOUGH MPV AND SLK
MAY STILL HANG ONTO MVFR UNTIL AROUND 16Z.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...PRETTY MUCH VFR THE
ENTIRE TIME THANKS TO HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...NASH
AVIATION...RJS/NASH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
634 PM EST MON DEC 10 2012
.SYNOPSIS...
WIDESPREAD LIGHT RAIN WILL MIX WITH AND CHANGE TO LIGHT SNOW LATER
THIS EVENING BEFORE TAPERING OFF OVERNIGHT. A FEW INCHES ARE
POSSIBLE...MAINLY OVER THE HIGHER TERRAIN OF THE NORTHERN MOUNTAINS.
SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN EXPECTED FROM
TUESDAY ONWARD INTO NEXT WEEKEND AS HIGH PRESSURE DOMINATES
REGIONAL WEATHER CONDITIONS. SEASONABLY COLD TEMPERATURES TUESDAY
INTO WEDNESDAY...WILL MODERATE BY LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 632 PM EST MONDAY...OVERALL FCST IN GOOD SHAPE WITH ONLY SOME
MINOR ADJUSTMENTS BASED ON CRNT TRENDS. LATEST SFC ANALYSIS PLACES
LOW PRES NORTH OF THE BORDER WITH ONE COLD FRNT ACRS THE CPV
ATTM...AND ANOTHER ONE APPROACHING THE SLV...WITH MUCH COLDER AIR
BEHIND THIS FRNT. THE FIRST FRNT HAS RESULTED IN AN OVERALL
INCREASE IN AREAL COVERAGE/INTENSITY OF RAIN SHOWERS ACRS THE CPV
AND PARTS OF CENTRAL/NORTHERN VT THIS EVENING...WITH ADDITIONAL
SHOWERS ACRS NORTHERN NY. WL CONT TO MENTION POPS AT 100% THRU
00Z...THEN START TO TAPER POPS OFF FROM THE SLV EASTWARD.
WHITEFACE OBS DOWN TO 28F...WHICH INDICATES THE COLDER AIR IS
MOVING IN ALOFT...BUT SFC TEMPS STILL REMAIN ABOVE 0C ACRS OUR
CWA...WHICH WL MAKE RAIN TO SNOW AND AMOUNT OF ACCUMULATION
DIFFICULT TONIGHT. BASED ON OBS AND LATEST RAP MODEL...THINKING
CHANGE OVER TO SNOW WL OCCUR AT SLK BTWN 01Z-02Z...MPV/BTV BY
05Z...AND ACRS EASTERN/SOUTHERN VT AFT 06Z. NEXT QUESTION WL BE
AMOUNT OF RH LEFTOVER...WHICH RAP/NAM SHOW QUICKLY DISSIPATING AS
THERMAL PROFILES BECM COLD ENOUGH FOR SNOW. THINKING THE
COMBINATION OF UPSLOPE FLW...SOME 1000 TO 700MB RH...AND FAVORABLE
BLOCKING/CONVERGENCE ACRS THE CPV...WL RESULT IN A PERIOD OF SNOW
SHOWERS WITH SOME ACCUMULATIONS...WHICH CRNT FCST HAS COVERED
NICELY. THINKING DUSTING TO AN INCH BTV/PBG...AROUND 2" FOR
ESSEX/JERICHO...AND UP TO 3" POSSIBLE NEAR UNDERHILL/STOWE/JAY
PEAK BY 12Z TUES AND A DUSTING TO SEVERAL INCHES FOR THE
DACKS...AND ONLY LIGHT AMOUNTS CT RIVER VALLEY AND SLV. WL CONT TO
MONITOR CRNT TRENDS FOR POTENTIAL ADJUSTMENTS...BUT OVERALL FCST
IN GOOD SHAPE.
FORECAST REMAINS ON TRACK FOR TONIGHT WITH NEAR TERM CHALLENGES
BEING THE OVERALL COVERAGE OF PCPN...AND THE EXTENT TO WHICH
COOLING NEAR-SFC THERMAL PROFILES OVERNIGHT LEAD TO MINOR SNOWFALL
ACCUMULATIONS. PARENT LOW PRESSURE SYSTEM RESPONSIBLE FOR THIS
AFTERNOON`S RAIN/SHOWERS CURRENTLY PASSING NORTHEAST THROUGH THE
SLV NEAR MONTREAL AND EXPECT THIS TREND TO CONTINUE TONIGHT. A
GENERAL REBLOSSOMING OF RAINFALL IS NOW OCCURRING ACROSS THE
REGION ASSOCIATED WITH WEAK SFC WAVE RIDING NORTHEAST ALONG LEAD
FRONTAL BOUNDARY FROM CENTRAL PA INTO CENTRAL/WRN NY STATE UP TO
THE PARENT LOW. AN ADDITIONAL 0.15 TO 0.25 INCHES OR SO IS
EXPECTED WITH THIS ACTIVITY THROUGH THE 00-02Z TIME FRAME AS THE
FRONT SWINGS THROUGH THE REGION. TEMPERATURES QUITE MILD THROUGH
EARLY EVENING...NOTED BY MANY READINGS IN THE 40S AND INTO LOWER
AND MID 50S IN SOME CASES AS OF 3 PM.
OF ADDITIONAL INTEREST IS THE PRIMARY POLAR FRONT STILL STATIONARY
FURTHER OFF TO THE NORTHWEST BEHIND THE LEADING FRONT. MUCH COLDER
AIR BACK BEHIND THIS SECONDARY BOUNDARY AND AS AFOREMENTIONED SFC
LOW SWINGS AWAY TO THE NORTHEAST...THIS FRONT WILL SURGE SOUTHEAST
AND OVERTAKE THE LEAD FRONT LATER THIS EVENING. FLOW TRENDS
NORTHWEST BEHIND THIS PASSAGE WITH STRONG CAA SETTING UP AS 925-850
MB THERMAL PROFILES CRASH AFTER MIDNIGHT. ALL RELIABLE MODELS SHOW
AT LEAST SOME CHANGEOVER TO SNOW DURING A 3-6 HOUR PERIOD FROM ABOUT
02Z-07Z AS THIS OCCURS AND BACK EDGE OF PCPN EXITS TO THE EAST. LOW
FROUDE NUMBER PROFILES SUPPORT AMPLE LOW LEVEL BLOCKING FAVORING THE
WESTERN SLOPES AS MEAN PBL WINDFLOW TRENDS NORTHWEST. HOWEVER...
PROBLEMATIC ISSUES ON POTENTIAL ACCUMULATIONS EXIST AS USUAL...AND
MAINLY CONCERN A NARROWING COLUMNAR MOISTURE DEPTH OVER TIME AND HOW
QUICKLY THE NEAR-SFC 2M TEMPERATURES CAN COOL AS EVIDENCED BY 12Z
3-HRLY MOS NUMBERS. AFTER USING SEVERAL METHODS...MY BEST ESTIMATE
IS FOR ONLY VERY LIGHT ACCUMULATIONS TO OCCUR IN THE LOWER
ELEVATIONS...SAY A DUSTING TO PERHAPS AN INCH...WITH A GENERAL 1-3
INCH ACCUMULATION EXPECTED ABOVE 1 KFT AND PERHAPS 3-5" NEAR THE
SUMMIT LEVEL. TEMPERATURES TO HOLD MILD THROUGH EARLY...THAN FALL
RATHER SHARPLY LATER TONIGHT BOTTOMING OUT FROM THE UPPER TEENS TO
MID 20S NORTH AND WEST...AND UPPER 20S/LOWER 30S SOUTH/SOUTHEAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 317 PM EST MONDAY...REMAINDER OF THE SHORT TERM THEN TRENDS
RELATIVELY QUITE AS CANADIAN HIGH PRESSURE SETTLES ATOP THE
REGION. OTHER THAN SOME LINGERING NRN MTN FLURRIES IN THE
MORNING...EXPECTING A CHILLY DAY ON TAP FOR TOMORROW (TUESDAY) AS
925 MB TEMPERATURES CONTINUE TO FALL INTO THE -8C TO -12C RANGE BY
MID-AFTERNOON UNDER MODEST NORTHWESTERLY GRADIENT. THIS SUPPORTS
HIGHS HOLDING MAINLY STEADY IN THE 20S FOR MOST LOCALES...THOUGH A
FEW LOWER 30S POSSIBLE IN FAVORED DOWNSLOPE REGIONS OF SOUTHERN
VT.
THEREAFTER...CLEAR TO PTLY CLOUDY SKIES CONTINUE TUESDAY NIGHT INTO
WEDNESDAY NIGHT WITH AFOREMENTIONED HIGH SLIDING SLOWLY ATOP AND
EAST OF THE REGION. AFTER A CHILLY NIGHT TUESDAY NIGHT IN THE
SINGLE DIGITS TO TEENS...READINGS TO REBOUND BACK TO NEAR SEASONAL
NORMS BY WEDNESDAY AS MODEST SOUTHWESTERLY RETURN FLOW DEVELOPS. AS
MENTIONED EARLIER...MAINLY DRY WEATHER EXPECTED DURING THESE
PERIODS...THOUGH I HAVE HINTED AT A FEW FLURRIES ACROSS THE
SLV/DACKS TO ACCT FOR ANY WEAK LAKE ENHANCED ACTIVITY THAT HI-RES
MODELS SUGGEST MAY BE DRIFTING AROUND.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 317 PM EST MONDAY...FIRST HALF OF THE EXTENDED PERIOD WILL
CONTINUE TO FEATURE RATHER QUIET WEATHER THANKS TO HIGH PRESSURE
RIDGING. THINGS GET MORE INTERESTING FOR LATER IN THE WEEKEND AND
EARLY NEXT WEEK WHEN IT APPEARS A MORE UNSETTLED PATTERN WILL SET
UP. UNFORTUNATELY, THE SPREAD IN GUIDANCE IS RATHER LARGE BY THIS
POINT, SO ALTHOUGH CONFIDENCE IS MODERATE/HIGH FOR THURSDAY AND
FRIDAY, IT`S LOW/VERY LOW BY SUNDAY & MONDAY. DAILY SPECIFICS
BELOW:
THURSDAY & FRIDAY: LOW/MID LEVEL RIDGE WILL PERSIST, RESULTING IN A
COUPLE OF DRY AND FAIRLY SUNNY DAYS. TEMPERATURES WILL BE SLIGHTLY
ABOVE NORMAL BOTH DAYS -- LOTS OF 30S THURSDAY AND 30S AND 40S
(LOWER ELEVATIONS) FOR FRIDAY AS 925MB TEMPERATURES CLIMB TO -2C TO
0C RANGE. STUCK CLOSE TO GUIDANCE FOR HIGH AND LOW TEMPERATURES.
SATURDAY: 12Z GFS AND EURO RUNS START TO DIVERGE AT THIS POINT. GFS
INDICATES A VERY WEAK UPPER TROF AND ASSOCIATED WEAK SURFACE LOW
WILL ZIP BY TO OUR NORTH, PERHAPS PRODUCING A FEW MOUNTAIN
FLURRIES. EURO IS EVEN WEAKER WITH THE FEATURE. SHOULD END OUT TO BE
ANOTHER DRY DAY OVERALL, BUT A LITTLE COOLER THAN FRIDAY AS THE MEAN
FLOW SHIFTS MORE WEST/NORTHWEST. AGAIN, STAYED CLOSE TO GUIDANCE FOR
TEMPERATURES.
SUNDAY: MODELS FOR SEVERAL RUNS HAVE BEEN SHOWING SOME SORT OF UPPER
TROF DIGGING TO OUR WEST, WHILE SURFACE LOW PRESSURE PUSHES OUT OF
THE GREAT LAKES AND TOWARD THE COAST. ALL RUNS HAVE BEEN DIFFERENT
IN THE DETAILS. EURO HAS BEEN MORE PROGRESSIVE AND FASTER WITH THIS,
AND THE 12Z EURO IS NO DIFFERENT -- WOULD SUGGEST LOTS OF CLOUDS AND
LIGHT PRECIPITATION BREAKING OUT SUNDAY MORNING. GFS HOLDS BACK A
MORE CUT-OFF LOW FARTHER TO THE SOUTHWEST, KEEPING THE DAY HERE
DRY, AND ONLY SKIMMING THE SOUTHERN HALF OF THE REGION WITH LIGHT
PRECIPITATION SUNDAY NIGHT AS IT SLIDES THE LOW SOUTH OF NEW ENGLAND.
GIVEN OVERALL TRACK RECORD OF EURO AND HPC`S FAVORING THAT MODEL,
HAVE PAINTED IN CHANCE LEVEL POPS FOR SUNDAY. MODEL PROFILES SUGGEST
THAT THERE COULD BE SOME MIXED PRECIPITATION, BUT THIS FAR OUT I
KEPT IT TO A SIMPLE RAIN/SNOW OPTION. TEMPERATURES -- STUCK A BIT
CLOSER TO THE EURO WHICH FEATURES MOST AREAS REACHING THE 35-40F
RANGE. GOOD DEAL OF BUST POTENTIAL HERE.
MONDAY: MODELS ARE ALL OVER THE PLACE, THOUGH ALL FEATURE SOME SORT
OF STRENGTHENING LOW PRESSURE -- WHETHER FAR SOUTHEAST OF NEW
ENGLAND (12Z GFS), EAST OF MAINE (00Z EURO), OR OVER THE
MID-ATLANTIC (12Z EURO). AT THIS POINT, BEST COURSE IS TO HAVE AT
LEAST CHANCE LEVEL POPS PAINTED IN ACROSS THE ENTIRE REGION. THE
12Z EURO TAKEN AT FACE VALUE WOULD SUGGEST A WET/WINDY/WARM STORM.
FOR TEMPERATURES, STARTED WITH THE EURO, BUT TOOK SEVERAL DEGREES
OFF. STILL ENDED UP WITH A LOT OF 40S FOR HIGHS.
I SUSPECT THE FORECASTS FOR THE WEEKEND AND EARLY NEXT WEEK ARE
GOING TO CHANGE QUITE A BIT BETWEEN NOW AND THEN...
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...LOTS OF MVFR AND IFR CEILINGS ACROSS THE
REGION, AND DONT EXPECT MUCH CHANGE FOR THE REMAINDER OF THE DAY
AND INTO THE OVERNIGHT. THERE ARE A FEW AREAS OF RAIN SHOWERS THAT
WILL AFFECT MOST LOCATIONS THROUGH 00Z. A COLD FRONT WILL PUSH
ACROSS THE REGION FROM WEST TO EAST DURING THE EARLY/MID EVENING
HOURS ACCOMPANIED BY A WIND SHIFT TO THE NORTHWEST AND PERHAPS
BRIEFLY GUSTY WINDS. COLDER AIR FILTING BEHIND WILL PRODUCE AT
LEAST A FEW HOURS OF LIGHT SNOW/SNOW SHOWER ACTIVITY AT ALL
TERMINAL LOCATIONS. CEILINGS AND VISIBILITIES WILL LIKELY BE
REDUCED BRIEFLY TO IFR LEVELS. CONDITIONS WILL IMPROVE TUESDAY
MORNING WITH CEILINGS LIFTING TO VFR LEVELS, THOUGH MPV AND SLK
MAY STILL HANG ONTO MVFR UNTIL 15Z OR SO.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...PRETTY MUCH VFR THE ENTIRE
TIME THANKS TO HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...NASH
AVIATION...NASH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EST SUN DEC 9 2012
.SYNOPSIS...
A WARM MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL
RESULT IN ABOVE NORMAL TEMPERATURES THROUGH MONDAY. THE COLD FRONT
WILL CROSS THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 920 PM SATURDAY...
THE MAIN UPDATES TO THE FORECAST THIS EVENING WILL BE TO ADDRESS
CLOUD COVER AND RAPIDLY FALLING TEMPS. MID CLOUDS UPSTREAM EARLIER
THIS EVENING WERE MORE ROBUST AND EVENING PRODUCING SOME VERY LIGHT
PRECIP OVER SOUTHWESTERN NC...BUT HAVE SINCE DECREASED IN COVERAGE
AS THEY DRIFT SOUTHWEST TO NORTHEAST ACROSS THE AREA. IN AREAS
WHERE SKIES HAVE BEEN MOSTLY CLEAR...PARTICULARLY OVER THE EASTERN
HALF OF THE CWA...TEMPS HAVE QUICKLY FALLEN INTO THE UPPER 40S AND
LOWER 50S. THE LATEST RAP CONTINUES TO INDICATE MOISTURE UPSTREAM
INTO THE AREA WITH A PERIOD OF ISENTROPIC LIFT SUFFICIENT FOR
SCATTERED SHOWERS...MAINLY AROUND THE WESTERN PIEDMONT. DUE TO THE
EXPECTED INCREASE IN MID LEVEL CLOUD COVER...IN THE 4000-6000 FT
RANGE BASED ON UPSTREAM OBS AND FORECAST SOUNDINGS...THERE IS STILL
SOME UNCERTAINTY REGARDING THE COVERAGE OF FOG/STRATUS. WHERE SKIES
ARE CLEAR...VISIBILITIES HAVE FALLEN INTO THE 3 TO 6 MILE RANGE IN
SOME SPOTS...BUT NO FURTHER. WILL CONTINUE TO MONITOR THESE TRENDS
TO SEE IF A DENSE FOG ADVISORY IS NEED LATER TONIGHT....BUT CURRENT
THINKING IS THAT IT MAY BE MORE LIKELY OVER EASTERN AREAS.
WITH TEMPS APPROACHING FORECAST MINS IN SOME OUTLYING AREAS...ALSO
IN RESPONSE TO THE CLEAR SKIES...WILL LOWER MIN TEMPS A COUPLE
DEGREES. HOWEVER...IF CLOUDS MOVE IN AS EXPECTED...TEMPS SHOULD
BEGIN TO LEVEL OUT AND REMAIN IN THE UPPER 40S AND LOWER 50S. -BLS
AFTER THE MORNING LOW CLOUDS/FOG LIFT AND DISPERSE AND ISOLATED
SHOWER ACTIVITY EXITS THE AREA...A MIX OF SUN AND CLOUDS WILL
SUPPORT DAYTIME HIGHS IN THE MID TO UPPER 60S NORTH TO LOWER/MID 70S
SOUTH.
THE UPSTREAM TROUGH WILL BEGIN TO DIG INTO THE SOUTHERN PLAINS
SUNDAY NIGHT WITH ATTENDANT SFC COLD FRONT ADVANCING EAST INTO THE
TN VALLEY. RISING PWATS FROM STRENGTHENING WARM MOIST AIR
ADVECTION...INCREASING RIGHT-ENTRANCE REGION DYNAMICS...THE
POTENTIAL FOR WEAK INSTABILITY ALOFT ALONG WITH THE PROSPECTS OF
SOME WEAK SHORTWAVE DISTURBANCES TO MOVE THROUGH THE AREA IN THE
SWLY FLOW ALOFT WILL SUPPORT ISOLATED SHOWERS...MAINLY IN THE WEST
LATE SUNDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM SUNDAY...
THE FAVORED EC MODEL CONTINUES TO SHOW LESS AND LESS IN THE WAY OF
SIGNIFICANT RAIN FOR CENTRAL NC WITH THE PASSAGE OF THE COLD FRONT
MONDAY NIGHT AND TUESDAY. EVEN TUESDAY IS MOSTLY DRY NOW WITH VERY
LITTLE IN THE WAY OF ANY POST-FRONTAL RAIN NOW FORECAST. THESE
TRENDS ARE SUPPORTED BY THE OPERATIONAL GFS/NAM.
TIMING OF THE FRONT... THE FRONT STILL APPEARS ON TARGET TO REACH
INTO THE NW PIEDMONT BY AROUND SUNSET MONDAY NIGHT. OUT AHEAD OF THE
FRONT... WARM AND BREEZY CONDITIONS ARE EXPECTED. HIGHS SHOULD
THREATEN DAILY RECORDS. SEE THE LIST BELOW IN THE CLIMATE SECTION.
THEN... A LINE OF SHOWERS IS EXPECTED TO PRECEDE THE FRONT INTO THE
WESTERN PIEDMONT BY SUNSET... THEN DIE OUT AS IT MOVES INTO THE MORE
STABLE AIR OUT OVER THE PIEDMONT. WE WILL KEEP LIKELY POP FOR LATE
MON AND MON EVENING IN THE WEST... WITH ONLY CHANCE POPS EAST.
THERE IS STILL A CHANCE OF SHOWERS INTO EARLY TUESDAY... OR PATCHY
LIGHT RAIN... BUT QPF SHOULD BE LESS THAN 0.25 FOR THE EVENT FOR
CENTRAL NC. LOCALLY UP TO 0.50 MAY FALL JUST TO OUR WEST IN THE
FOOTHILLS.
EXPECT SKIES TO BECOME PARTLY SUNNY TUESDAY... BREEZY AND COOLER.
HIGHS IN THE 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LATEST MODELS ARE COMING MORE IN LINE WITH A SOLUTION THAT KEEPS
THE BEST CHANCE OF SIGNIFICANT RAIN ALONG THE COAST WEDNESDAY AND
WEDNESDAY NIGHT. EVEN THE LATEST AND FAVORED OPERATIONAL EUROPEAN
MODEL KEEPS THE BEST RAIN ALONG THE COAST AND OFFSHORE WHERE THE
MAIN WAVES OF LOW PRESSURE FORM ALONG THE BAROCLINIC ZONE. IT IS
LOOKING MORE AND MORE LIKE A DRY WEEK FOR CENTRAL NC.
WE WILL MAINTAIN A CHANCE OF RAIN IN THE EAST LATE TUESDAY NIGHT AND
WEDNESDAY... WITH ONLY A SLIGHT CHANCE INTO THE SE PIEDMONT AND
COASTAL PLAIN. OTHERWISE... GENERALLY DRY WEATHER IS EXPECTED
TUESDAY... THURSDAY AND FRIDAY WITH COOLER TEMPS BACK TOWARD
SEASONAL NORMALS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 235 AM SUNDAY...
24-HR TAF PERIOD:
A FAIR AMOUNT OF UNCERTAINTY PERSISTS WITH REGARD TO HOW LOW
CEILINGS AND VISBYS WILL FALL THROUGH 12Z THIS MORNING. INCREASING
LOW AND MID-LEVEL CLOUD COVER SHOULD PREVENT VISBYS LOWER THAN
MVFR/IFR IN MOST LOCATIONS...EXCEPT PERHAPS AT THE RWI AND FAY
TERMINALS. REGARDLESS OF VISBYS...MVFR/IFR CEILINGS WILL BE POSSIBLE
AT THE RDU/INT/GSO TERMINALS BETWEEN 06-12Z...PRIMARILY AT INT/GSO
WHERE ELEVATED SHOWER ACTIVITY WILL BE POSSIBLE. EXPECT SUB-VFR FOG
OR CEILINGS TO LIFT AND IMPROVE BETWEEN 12-15Z...WITH VFR CONDITIONS
LIKELY IN MOST AREAS BY 15-18Z...EXCEPT PERHAPS AT THE INT/GSO
TERMINALS WHERE MVFR CEILINGS MAY PERSIST INTO THE AFTERNOON.
CEILINGS ARE EXPECTED TO DETERIORATE TO LIFR BETWEEN 03-12Z MONDAY
AS SOUTHWESTERLY FLOW ADVECTS LOW-LEVEL MOISTURE INTO
LOOKING AHEAD:
LIFR CEILINGS ARE EXPECTED TO LIFT AND IMPROVE TO MVFR...PERHAPS
VFR...BETWEEN 12-18Z MONDAY AS A COLD FRONT APPROACHES THE MOUNTAINS
FROM THE WEST AND SOUTHWESTERLY WINDS STRENGTHEN TO 15-20 KT WITH
GUSTS UP TO 30 KT. A PERIOD OF MVFR CEILINGS AND SHOWER ACTIVITY
WILL BE POSSIBLE AS THE FRONT CROSSES THROUGH THE CAROLINAS MONDAY
NIGHT AND TUESDAY MORNING...WITH A POTENTIAL FOR A PROLONGED PERIOD
OF MVFR/IFR CEILINGS AT THE FAY/RWI TERMINALS TUESDAY INTO WEDNESDAY
AS THE FRONT TEMPORARILY STALLS NEAR OR JUST OFFSHORE THE CAROLINA
COAST. -VINCENT
&&
.CLIMATE...
DAILY RECORD HIGHS FOR MONDAY (DECEMBER 10):
RDU: 81 (2007)
GSO: 78 (2007)
FAY 79 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...CBL/BLS
SHORT TERM...BADGETT
LONG TERM....BADGETT
AVIATION...VINCENT
CLIMATE...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
237 AM EST SUN DEC 9 2012
.SYNOPSIS...
A WARM MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL
RESULT IN ABOVE NORMAL TEMPERATURES THROUGH MONDAY. THE COLD FRONT
WILL CROSS THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 920 PM SATURDAY...
THE MAIN UPDATES TO THE FORECAST THIS EVENING WILL BE TO ADDRESS
CLOUD COVER AND RAPIDLY FALLING TEMPS. MID CLOUDS UPSTREAM EARLIER
THIS EVENING WERE MORE ROBUST AND EVENING PRODUCING SOME VERY LIGHT
PRECIP OVER SOUTHWESTERN NC...BUT HAVE SINCE DECREASED IN COVERAGE
AS THEY DRIFT SOUTHWEST TO NORTHEAST ACROSS THE AREA. IN AREAS
WHERE SKIES HAVE BEEN MOSTLY CLEAR...PARTICULARLY OVER THE EASTERN
HALF OF THE CWA...TEMPS HAVE QUICKLY FALLEN INTO THE UPPER 40S AND
LOWER 50S. THE LATEST RAP CONTINUES TO INDICATE MOISTURE UPSTREAM
INTO THE AREA WITH A PERIOD OF ISENTROPIC LIFT SUFFICIENT FOR
SCATTERED SHOWERS...MAINLY AROUND THE WESTERN PIEDMONT. DUE TO THE
EXPECTED INCREASE IN MID LEVEL CLOUD COVER...IN THE 4000-6000 FT
RANGE BASED ON UPSTREAM OBS AND FORECAST SOUNDINGS...THERE IS STILL
SOME UNCERTAINTY REGARDING THE COVERAGE OF FOG/STRATUS. WHERE SKIES
ARE CLEAR...VISIBILITIES HAVE FALLEN INTO THE 3 TO 6 MILE RANGE IN
SOME SPOTS...BUT NO FURTHER. WILL CONTINUE TO MONITOR THESE TRENDS
TO SEE IF A DENSE FOG ADVISORY IS NEED LATER TONIGHT....BUT CURRENT
THINKING IS THAT IT MAY BE MORE LIKELY OVER EASTERN AREAS.
WITH TEMPS APPROACHING FORECAST MINS IN SOME OUTLYING AREAS...ALSO
IN RESPONSE TO THE CLEAR SKIES...WILL LOWER MIN TEMPS A COUPLE
DEGREES. HOWEVER...IF CLOUDS MOVE IN AS EXPECTED...TEMPS SHOULD
BEGIN TO LEVEL OUT AND REMAIN IN THE UPPER 40S AND LOWER 50S. -BLS
AFTER THE MORNING LOW CLOUDS/FOG LIFT AND DISPERSE AND ISOLATED
SHOWER ACTIVITY EXITS THE AREA...A MIX OF SUN AND CLOUDS WILL
SUPPORT DAYTIME HIGHS IN THE MID TO UPPER 60S NORTH TO LOWER/MID 70S
SOUTH.
THE UPSTREAM TROUGH WILL BEGIN TO DIG INTO THE SOUTHERN PLAINS
SUNDAY NIGHT WITH ATTENDANT SFC COLD FRONT ADVANCING EAST INTO THE
TN VALLEY. RISING PWATS FROM STRENGTHENING WARM MOIST AIR
ADVECTION...INCREASING RIGHT-ENTRANCE REGION DYNAMICS...THE
POTENTIAL FOR WEAK INSTABILITY ALOFT ALONG WITH THE PROSPECTS OF
SOME WEAK SHORTWAVE DISTURBANCES TO MOVE THROUGH THE AREA IN THE
SWLY FLOW ALOFT WILL SUPPORT ISOLATED SHOWERS...MAINLY IN THE WEST
LATE SUNDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SATURDAY...
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY...ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES
AMONG THE MODELS...BUT THERE CONTINUES TO SOME TREND OF A SLOWER
PASSAGE. AHEAD OF THE FRONT...INCREASING SOUTHWESTERLY WINDS WILL
USHER IN MOISTURE AND EVEN MORE WARMTH DURING THE DAY ON MONDAY.
TEMPS ARE EXPECTED TO RANGE FROM THE LOW 70S ACROSS THE NORTHWEST TO
THE MID 70S FURTHER SOUTH AND EAST. THERE COULD EVEN BE SOME UPPER
70S ACROSS THE SOUTHEAST...ALTHOUGH THE AMOUNT OF CLOUD COVER WILL
BE THE DETERMINING FACTOR AND AT THIS TIME...IT LOOKS LIKE THERE
WILL BE SUFFICIENT CLOUD COVER TO HOLD TEMPS DOWN SOME. HEATING MAY
ALSO BE TEMPERED SOME IN THIS REGION AS DEWPOINTS RISE INTO THE
LOWER 60S.
PRECIP CHANCES WILL INCREASE DURING THE DAY ON MONDAY AS WARM AIR
ADVECTION INCREASES ACROSS THE REGION...WITH SOME SPOTTY SHOWERS
POSSIBLE DURING THE DAY. THE BEST CHANCE OF PRECIP WILL COME
OVERNIGHT ON MONDAY AND INTO EARLY TUESDAY AS THE FRONT CROSSES THE
AREA. AS STATED ABOVE...THERE ARE SOME TIMING DIFFERENCES WITH
RESPECT TO THE SPEED OF THE FRONT...BUT WILL CONTINUE TO SHOW PRECIP
CHANCES TRENDING DOWNWARD LATE TUESDAY AFTERNOON/EVENING.
INSTABILITY APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES
THE AREA MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
SLIGHTLY SLOWER FRONTAL TIMING...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S TO LOW/MID 60S AND MAY VERY WELL OCCUR IN THE
MORNING AND THEN FALL THROUGHOUT THE DAY. OVERNIGHT LOWS TUESDAY
NIGHT WILL LIKELY BE IN THE MID/UPPER 30S TO NEAR 40 DEGREES.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...
WEDNESDAY THROUGH THURSDAY...THEN THERE IS QUITE A BIT OF
UNCERTAINTY WITH RESPECT TO THE WEATHER FOR THIS TIME FRAME. BOTH
THE GFS AND ECMWF SHOW THE FRONT HANGING NEAR THE COAST WITH
MULTIPLE LOW PRESSURE WAVES TRACKING ALONG IT AND SPREADING PRECIP
INTO EASTERN NC...ALTHOUGH HOW FAR EAST IS IN QUESTION. THE GFS THEN
SHOWS A MID LEVEL KICKER WAVE MOVING INTO THE AREA WEDNESDAY WHICH
WOULD PUSH THE FRONT AND ASSOCIATED PRECIP OUT TO SEA. THE ECMWF IS
ALMOST 12-18 HOURS SLOWER WITH THIS MID LEVEL WAVE...HOWEVER THIS IS
SLIGHTLY FASTER THAN PREVIOUS RUNS OF THE ECMWF...SO THIS WILL HAVE
TO BE MONITORED. FOR NOW...WILL GO NO MORE THAN SLIGHT CHANCE POPS
FOR THIS TIME FRAME UNTIL MODELS COME INTO BETTER AGREEMENT AND WILL
JUST KEEP POPS CONFINED TO THE EASTERN PORTIONS OF THE FORECAST
AREA. TEMPS WILL LIKELY BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THIS
TIME FRAME.
FRIDAY THOUGH SATURDAY...CONDITIONS THEN LOOK TO IMPROVE FOR THE END
OF THE WORK WEEK AS SURFACE HIGH PRESSURE AND MID LEVEL RIDGING
BUILD INTO THE AREA. MODELS THEN SHOW THE NEXT SYSTEM APPROACHING
THE REGION OVER THE WEEKEND...WITH CLOUDS AND PRECIP CHANCES
POSSIBLY BEGINNING TO INCREASE LATE SATURDAY (ALTHOUGH TIMING THIS
FAR OUT IS ALWAYS IN QUESTION). TEMPS WILL SLOWLY MODERATE AT THE
END OF THE WEEK AND ESPECIALLY INTO SATURDAY AS THE SURFACE HIGH
MOVES OFFSHORE AND SOUTHERLY FLOW RETURNS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 235 AM SUNDAY...
24-HR TAF PERIOD:
A FAIR AMOUNT OF UNCERTAINTY PERSISTS WITH REGARD TO HOW LOW
CEILINGS AND VISBYS WILL FALL THROUGH 12Z THIS MORNING. INCREASING
LOW AND MID-LEVEL CLOUD COVER SHOULD PREVENT VISBYS LOWER THAN
MVFR/IFR IN MOST LOCATIONS...EXCEPT PERHAPS AT THE RWI AND FAY
TERMINALS. REGARDLESS OF VISBYS...MVFR/IFR CEILINGS WILL BE POSSIBLE
AT THE RDU/INT/GSO TERMINALS BETWEEN 06-12Z...PRIMARILY AT INT/GSO
WHERE ELEVATED SHOWER ACTIVITY WILL BE POSSIBLE. EXPECT SUB-VFR FOG
OR CEILINGS TO LIFT AND IMPROVE BETWEEN 12-15Z...WITH VFR CONDITIONS
LIKELY IN MOST AREAS BY 15-18Z...EXCEPT PERHAPS AT THE INT/GSO
TERMINALS WHERE MVFR CEILINGS MAY PERSIST INTO THE AFTERNOON.
CEILINGS ARE EXPECTED TO DETERIORATE TO LIFR BETWEEN 03-12Z MONDAY
AS SOUTHWESTERLY FLOW ADVECTS LOW-LEVEL MOISTURE INTO
LOOKING AHEAD:
LIFR CEILINGS ARE EXPECTED TO LIFT AND IMPROVE TO MVFR...PERHAPS
VFR...BETWEEN 12-18Z MONDAY AS A COLD FRONT APPROACHES THE MOUNTAINS
FROM THE WEST AND SOUTHWESTERLY WINDS STRENGTHEN TO 15-20 KT WITH
GUSTS UP TO 30 KT. A PERIOD OF MVFR CEILINGS AND SHOWER ACTIVITY
WILL BE POSSIBLE AS THE FRONT CROSSES THROUGH THE CAROLINAS MONDAY
NIGHT AND TUESDAY MORNING...WITH A POTENTIAL FOR A PROLONGED PERIOD
OF MVFR/IFR CEILINGS AT THE FAY/RWI TERMINALS TUESDAY INTO WEDNESDAY
AS THE FRONT TEMPORARILY STALLS NEAR OR JUST OFFSHORE THE CAROLINA
COAST. -VINCENT
&&
.CLIMATE...
DAILY RECORD HIGHS FOR MONDAY (DECEMBER 10):
RDU: 81 (2007)
GSO: 78 (2007)
FAY 79 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM....KRR
AVIATION...VINCENT
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
631 PM EST MON DEC 10 2012
.SYNOPSIS...
A STRONG COLD FRONT DEPARTS TO THE EAST THROUGH THE NIGHT. HIGH
PRESSURE BUILDS MID WEEK AND LINGERS INTO FRIDAY. NEXT
PRECIPITATION MAKER LONG ABOUT SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
SURFACE COLD FRONT IS CURRENTLY CROSSING OHIO RIVER...PER OBS AND
RADAR. THE ENHANCED PRECIP BEHIND THE FRONT APPEARS TIED TO THE 925
MB FRONT. BECAUSE OF THIS ENHANCEMENT BEHIND THE SURFACE FRONT DID
DRAW HIGHER POPS A LITTLE FARTHER WEST THAN PREVIOUS FORECAST.
PRECIP OUT AHEAD OF THE FRONT HAS BEEN FAIRLY LIGHT...WITH LIGHT
RAIN OR EVEN JUST SOME MIST/SPRINKLES BEING REPORTED BY ASOS/S
ACROSS THE FORECAST AREA. HAVE SEEN SOME LIGHTNING JUST WEST AND
NORTH OF OUR CWA...AGAIN IT SEEMS TIED MOST CLOSELY TO THE 925 FRONT
AND UPPER LEVEL ENHANCEMENT PROVIDED BY A VORT MAX RIDING UP THE
FRONT. THAT VORT MAX HAS MOVED OFF THE NORTHEAST AND HAVE NOT SEEN
ANY LIGHTNING FOR ABOUT AN HOUR...HOWEVER RAP SHOWING ANOTHER VORT
MAX SHOULD RIDE NE ALONG THE FRONT THIS AFTERNOON...SO TRIED TO TIE
SOME SLIGHT CHANCE THUNDER TO THE 925 FRONT AND 500MB VORT MAX
COMBINATION. REALLY SHOULD NOT BE MORE THAN SOME RANDOM STRIKES
THROUGH THE AFTERNOON. MOST LOCATIONS ACROSS WV AT OR NEAR THEIR
HIGH FOR THE DAY...WITH FALLING TEMPERATURES ALREADY SHOWING UP
BEHIND THE FRONT IN SE OHIO. EXPECT A QUICK 5-10 DEGREE DROP IN THE
HOUR TO TWO AFTER THE FRONT PASSES...WITH A SLOWER COOLING TREND
AFTER THAT INTO TONIGHT. LAV GUIDANCE SEEMED FAIRLY CLOSE TO CURRENT
TRENDS...SO USED THAT AS A STARTING POINT FOR TODAYS NON-DIURNAL
CURVE.
PRECIPITATION WILL SLOWLY COME TO AN END OVERNIGHT FROM WEST TO EAST
AS THE SYSTEM MOVES EAST AND HIGH PRESSURE BEGINS TO BUILD TO THE
WEST. AS COOLER TEMPERATURES ALOFT MOVE IN...WILL SEE A TRANSITION
FROM RAIN TO SNOW JUST AS THE PRECIP IS MOVING OUT. SHOULD NOT SEE
ANY ACCUMULATIONS IN THE LOWLANDS...WITH GENERALLY 2 INCHES OR LESS
AT THE HIGHEST ELEVATIONS IN THE WV MOUNTAINS.
TOMORROW WILL FEEL CHILLY COMPARED TO WHAT WE HAVE SEEN IN DECEMBER
SO FAR...BUT IN REALITY WE WILL ONLY BE 5-7 DEGREES BELOW NORMAL
WITH HIGHS IN THE UPPER 30S AND LOWER 40S ACROSS THE LOWLANDS...AND
MID TO UPPER 30S IN THE MOUNTAINS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
SHOULD SEE MOST AREAS CLR TUESDAY NIGHT. THERE MAY BE SOME HIGH CLDS
ACROSS THE MTNS FROM UPR TROF. WITH THIS IN MIND...TRIED TO PLAY
MORE A RADIATIONAL COOLING SCENARIO HITTING THE TYPICAL COLD SPOTS
HARD. HAVE LOWS GENERALLY IN THE LOW TO MID 20S...WITH SOME TEENS IN
THE N MTN VALLEYS.
UPR TROF AXIS SHIFTS E ON WEDNESDAY. HOWEVER...LLVL THERMAL TROF
HANGS AROUND WITH ONLY A SLIGHT IMPROVEMENT IN TEMPS DESPITE
SUNSHINE.
ANOTHER COLD NIGHT WEDNESDAY NIGHT WITH READINGS SIMILAR OR A TICK
LWR THAN TUESDAY NIGHT.
UPR RIDGING BUILDS INTO AREA ON THURSDAY WITH LLVL FLOW TURNING SW.
THIS SHOULD ALLOW FOR A MORE MARKED REBOUND OF TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
TRIED TO KEEP MOUNTAIN VALLEYS COLDER THAN HPC GUIDANCE FOR THURSDAY
NIGHT...FIGURING WARMING MAINLY ALOFT AND STILL LIGHT WINDS...TO
ALLOW INVERSION TO SET UP.
ANOTHER NICE DECEMBER DAY EXPECTED ON FRIDAY. PROBABLY THE WARMEST
AFTERNOON TEMPERATURES OF THIS EXTENDED PERIOD.
WAS A BIT SLOWER INCREASING POPS SATURDAY AFTERNOON AND
EVENING...BUT AGAIN LOOKS TO BE RAIN. WILL INCREASE POPS TO LIKELY
FOR OVERNIGHT SATURDAY NIGHT.
HARD TO DETERMINE HOW LONG THE DEEP MOISTURE HOLDS IN ON SUNDAY.
BUT SOME COLDER AIR FINALLY LEAKS IN AGAIN SUNDAY NIGHT...DO MENTION
SOME SNOW SHOWERS SUNDAY NIGHT IN THE MOUNTAINS.
AS IS A FREQUENT PROBLEM IN WINTER...DAY 7 CONFIDENCE IS LOW...BUT
DID STAY A BIT COLDER THAN GUIDANCE...FIGURING ON 850 TEMPS STILL
NEAR OR SLIGHTLY BELOW ZERO CELSIUS.
&&
.AVIATION /00Z MONDAY THROUGH SATURDAY/...
A COLD FRONT WILL PULL OFF TO THE EAST...LEAVING LOW CLOUDS AND
NORTHWESTERLY WINDS BEHIND IT. SOME PATCHY LIGHT RAIN WILL CONTINUE
THIS EVENING...POSSIBLY CHANGING TO SNOW BEFORE ENDING. CLOUDS WILL
GRADUALLY LIFT ON TUESDAY...AND THEN DISSIPATE LATER IN THE DAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF LIFTING CLOUDS COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H H H M M H H H
HTS CONSISTENCY H M H H H H H H H H H H
BKW CONSISTENCY M M M H H H H H H H H H
EKN CONSISTENCY M L M H H H M M M M M L
PKB CONSISTENCY M M M H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z WEDNESDAY...
NONE.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26
NEAR TERM...MZ
SHORT TERM...30
LONG TERM...KTB
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1253 AM EST SUN DEC 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE GREAT LAKES IN THE WAKE OF A
DEPARTING COLD FRONT TONIGHT. THIS WILL GIVE A BRIEF RESPITE TO
THE RAINFALL UNTIL A WARM FRONT DEVELOPS OVER KENTUCKY EARLY
SUNDAY AND THEN LIFTS NORTHWARD. LOW PRESSURE WILL THEN TRACK
NORTHEAST THROUGH THE OHIO VALLEY AND ANOTHER COLD FRONT OVER THE
AREA WILL BE THE FOCUS FOR MORE RAINFALL SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN DEVELOPING ACROSS
KENTUCKY OVER THE PAST FEW HOURS WITH A WARM FRONT OVER THE AREA.
EXPECT THE SHOWERS TO REMAIN MAINLY ALONG AND SOUTH OF THE OHIO
RIVER INTO THE EARLY MORNING HOURS PER THE LATEST HRRR AND RAP13
RUNS...BUT THE RAIN WILL LIKELY BEGIN TO SPREAD FURTHER NORTH
TOWARDS DAYBREAK. BUMPED UP POPS A BIT TO ACCOUNT FOR THIS. REST
OF FORECAST LARGELY REMAINS ON TRACK WITH ONLY A FEW MINOR TWEAKS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
WARM FRONT OVER KENTUCKY LIFTS NORTH THROUGH OHIO DURING THE DAY
SUNDAY AND A SURFACE LOW TRACKS EAST ALONG IT AS IT DOES. THE
COMBINATION OF THE TWO WILL MEAN ANOTHER MILD DAY WITH AN EVER-
INCREASING CHANCE FOR SHOWERS.
ONCE THE LOW REACHES LAKE ERIE SUNDAY NIGHT...A COLD FRONT
ORIENTED ALONG THE I-71 CORRIDOR WILL BE A FOCUS FOR SHOWERS AND
EVEN SOME THUNDERSTORMS. RAIN AT TIMES COULD BE MODERATE IN
INTENSITY AND RIVERS AND STREAMS THAT MAY BE RUNNING HIGH WILL
NEED TO BE MONITORED A LITTLE CLOSER AS THE NEXT ROUND OF RAIN
COMES IN. THE MODERATE RAINFALL WILL PROBABLY OCCUR IN THE LATER
EVENING AS THE FLOW AT THE SURFACE AND ALOFT IS NEAR PARALLEL
SOUTHWEST TO NORTHEAST. THIS WILL TAP THE AVAILABLE GULF MOISTURE
WITH A STRONG TRANSPORT WIND OVER THE REGION UNTIL THE SURFACE
GRADUALLY SHOWS AND EASTWARD PROGRESSION ON MONDAY IN RESPONSE TO
THE COLDER AIR BEING USHERED IN ON NORTHWEST WINDS.
A LARGE PORTION OF THE ATMOSPHERE WILL SEE QUITE A BIT OF
SLANTWISE CONVECTION AND THE THREAT FOR THUNDER IN THESE SHOWERS
IS HIGHER THAN AVERAGE...THOUGH THE SEVERE THREAT INHERENT WITH
THUNDERSTORMS WILL BE QUITE MINIMAL IF IT DOES EXIST AT ALL. I
TOOK NAM CAPE VALUES OVER 30 TO INDICATE THE THREAT FOR THUNDER.
WITH REGARDS TO THE HEAVIER RAIN...THIS STARTED SUNDAY EVENING AND
RAN THROUGH MONDAY EVENING WHERE POPS LIKELY OR HIGHER WERE BEING
FORECAST. THE RAIN WILL TURN OFF NORTHWEST TO SOUTHEAST ON MONDAY
WITH VERY LITTLE ACTIVITY SLATED TO REMAIN MONDAY NIGHT. THE
DEEPER COLD AIR IS WELL BEHIND THE RAINFALL SO I HAVE REMOVED
MENTION OF ANY SNOW.
TEMPERATURES WERE ONLY MINORLY ADJUSTED AND ARE SHOWING A PRETTY
GOOD CONSISTENCY BETWEEN GUIDANCE VALUES AND THE PREVIOUS
FORECAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS THE PERIOD BEGINS...THE MODELS ARE SHOWING SFC HIGH PRESSURE
BEGINNING TO PUSH INTO THE REGION. THE HIGH STRENGTHENS IT GRIP OVER
THE REGION DURING THE DAY TUESDAY. THE CENTER OF THE HIGH WILL
STRETCH OVER THE UPPER OHIO VALLEY BY DAYBREAK ON WEDNESDAY AND HIGH
PRESSURE WILL CONTROL THE REGIONS WEATHER INTO FRIDAY.
RIGHT NOW MODELS ARE IN GOOD AGREEMENT IN FORMING A SFC LOW IN THE
PLAINS ON FRIDAY AND EJECTING IT OUT INTO THE WESTERN LAKES BY
SATURDAY. FA WILL ONCE AGAIN BE ON THE WARM SIDE OF THE SYSTEM...SO
IT LOOKS LIKE A ANOTHER SHOT OF RAIN FOR NEXT SATURDAY.
TUESDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH CAA BEHIND THE
DEPARTING SYSTEM. HIGH WILL ONLY BE IN THE MID 30S TO AROUND 40.
MOSTLY CLEAR SKIES TUESDAY WITH THE BUILDING HIGH SHOULD ALLOW
TEMPERATURES TO FALL BACK INTO THE LOWER TO MID 20S. A GRADUAL WARM
UP THEN BEGINS ON WEDNESDAY AS HIGH ARE EXPECTED TO PUSH INTO THE
LOWER TO MID 40S. HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY
THE END OF THE WEEK.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
AHEAD OF THE DEVELOPING SYSTEM BY THE END OF THE PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
REMAINING MVFR CIGS WILL GRADUALLY LOWER TO IFR THIS MORNING AS A
WARM FRONT TO OUR SOUTH BEGINS TO LIFT NORTHWARD ACROSS THE AREA.
SHOWERS ALONG THIS FRONT SHOULD REMAIN CONFINED TO THE SOUTHERN
TERMINALS THIS MORNING. AREAS OF MVFR MIST WILL BE LIKELY ACROSS
THE KDAY/KILN THROUGHOUT TONIGHT. AS THE WARM FRONT LIFTS NORTH OF
THE TERMINALS DURING THE LATE MORNING...CIGS SHOULD RAISE BACK TO
MVFR. THE WARM FRONT MAY NOT MAKE IT AS FAR AS KDAY...SO KEPT IFR
CIGS IN THEIR FORECAST THROUGHOUT THE DAY. BY LATE THIS
AFTERNOON...SHOWERS AND POSSIBLY IFR CIGS WILL SPREAD ACROSS ALL
TERMINALS AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM. THERE MAY BE
ENOUGH INSTABILITY ACROSS THE SOUTHERN TERMINALS LATE THIS
AFTERNOON TO PRODUCE SOME THUNDER AS WELL. PRECIPITATION IS
EXPECTED TO AFFECT ALL TERMINALS THEREAFTER THROUGH THE END OF THE
TAF PERIOD.
OUTLOOK...IFR CEILINGS AND MVFR VISIBILITIES LIKELY LATE SUNDAY
NIGHT WITH IMPROVEMENT TO MVFR CEILINGS ON MONDAY. MVFR CEILINGS
MAY LINGER INTO MONDAY NIGHT AND TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1000 PM EST MON DEC 10 2012
.SYNOPSIS...
COLDER AIR WILL SWEEP INTO THE REGION TONIGHT BEHIND A COLD FRONT.
RECENT WET WEATHER WILL GIVE WAY TO COLDER AND DRIER CONDITIONS
FOR TUESDAY AND THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC COLD FRONT IN NOW EXITING LANCASTER COUNTY. RAIN SHOWERS HAVE
CHANGED TO SNOW SHOWERS OVER PORTIONS OF THE LAUREL HIGHLANDS...
WEST CENTRAL MOUNTAINS AND NORTHWEST MOUNTAINS. WITH FROPA...TEMPS
IN THE LOWER 50S HAVEN FALLEN BACK THROUGH THE 40S AND INTO THE
MID TO UPPER 30S OVER THE WEST AND NORTH. DESPITE MARGINAL TEMPS...
STILL EXPECT A COATING OF SNOW ON THE HIGHER RIDGES. ELSEWHERE..NO
ACCUMS ARE EXPECTED.
COLDER AIR CONTINUES TO WORK IN OVERNIGHT...TAKING A GOOD PORTION OF
THE OVERNIGHT TO REACH THE LOWER SUSQ. AIR STILL NOT FORMIDABLE
FOR DECEMBER THOUGH...AS THESE READINGS REMAIN WELL ABOVE NORMAL
FOR THIS TIME OF YEAR. HIGH PRESSURE BEGINS TO BUILD IN LATE
TONIGHT INTO TUE AS CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING
FOR MOST...POSS TUE AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
23Z SFC ANALYSIS SHOWS A COLD FRONT BISECTING PA...RUNNING FROM
ELM SOUTHWARD THRU UNV AND JST. SHIFTING WINDS TO THE NW BEHIND
THE FRONT WILL CAUSE LINGERING MOISTURE TO ASCEND THE
ALLEGHENIES...BRINGING CONTINUED -SRHA AND IFR CIGS AT JST THRU
AT LEAST MIDNIGHT. LATEST RUC SOUNDINGS SUGGEST A CHANGEOVER TO SNOW AT
BFD BY ARND 01Z...WITH IFR CIGS/VSBYS LIKELY THERE ALSO THRU AT
LEAST MIDNIGHT.
FURTHER EAST...LOW LVL STABLE AIR MASS PERSISTS ACROSS THE SUSQ
VALLEY...WHERE LOW CIGS/FOG ARE REPORTED AT 23Z. HOWEVER...PASSAGE
OF COLD FRONT /ARND 01Z AT IPT AND 03Z AT MDT AND LNS/ WILL BRING
A WSHIFT TO THE NW WITH RAPIDLY IMPROVING CONDS.
LINGERING MVFR CIGS AND SCT -SHSN MAY PERSIST FROM MIDNIGHT THRU
MIDDAY TUE AT BFD/JST...WHILE DOWNSLOPING NW FLOW LIKELY BRINGS A
RETURN TO VFR CONDS EAST OF THE MTNS.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
835 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT. WET WEATHER WILL
GIVE WAY TO COLDER AND DRIER CONDITIONS FOR TUESDAY AND THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC COLD FRONT HAS PASSED KUNV IN THE PAST HALF HOUR AND EXTENDS
FROM 30W KELN THROUGH KAOO SOUTHWARD TO KCBE. TEMPS IN THE LOWER
50S QUICKLY FALL BACK THROUGH THE 40S AND INTO THE UPPER 30S
BEHIND THE FRONT. THE HIGHEST TERRAIN OF THE WEST CENTRAL
MOUNTAINS AND NORTHWEST MOUNTAINS CHANGED OVER AS EXPECTED...WITH
KDUJ AND KBFD REPORTING 6SM AND 8SM VSBYS IN LIGHT SNOW WITH SFC
TEMPS IN THE MID TO UPPER 30S. WE ARE STILL EXPECTING A COATING OF
SNOW ON THOSE HIGHER RIDGES. ELSEWHERE..NO ACCUMS ARE EXPECTED.
COLDER AIR EVENTUALLY WORKS IN OVERNIGHT...IMPACTING NW MTNS
FIRST...BUT WILL TAKE A GOOD PORTION OF THE OVERNIGHT TO REACH THE
LOWER SUSQ. AIR STILL NOT FORMIDABLE FOR DECEMBER THOUGH...AS
THESE READINGS REMAIN WELL ABOVE NORMAL FOR THIS TIME OF YEAR.
HIGH PRESSURE BEGINS TO BUILD IN LATE TONIGHT INTO TUE AS
CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING FOR MOST...POSS TUE
AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
23Z SFC ANALYSIS SHOWS A COLD FRONT BISECTING PA...RUNNING FROM
ELM SOUTHWARD THRU UNV AND JST. SHIFTING WINDS TO THE NW BEHIND
THE FRONT WILL CAUSE LINGERING MOISTURE TO ASCEND THE
ALLEGHENIES...BRINGING CONTINUED -SRHA AND IFR CIGS AT JST THRU
AT LEAST MIDNIGHT. LATEST RUC SOUNDINGS SUGGEST A CHANGEOVER TO SNOW AT
BFD BY ARND 01Z...WITH IFR CIGS/VSBYS LIKELY THERE ALSO THRU AT
LEAST MIDNIGHT.
FURTHER EAST...LOW LVL STABLE AIR MASS PERSISTS ACROSS THE SUSQ
VALLEY...WHERE LOW CIGS/FOG ARE REPORTED AT 23Z. HOWEVER...PASSAGE
OF COLD FRONT /ARND 01Z AT IPT AND 03Z AT MDT AND LNS/ WILL BRING
A WSHIFT TO THE NW WITH RAPIDLY IMPROVING CONDS.
LINGERING MVFR CIGS AND SCT -SHSN MAY PERSIST FROM MIDNIGHT THRU
MIDDAY TUE AT BFD/JST...WHILE DOWNSLOPING NW FLOW LIKELY BRINGS A
RETURN TO VFR CONDS EAST OF THE MTNS.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
748 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT. WET WEATHER WILL
GIVE WAY TO COLDER AND DRIER CONDITIONS FOR TUESDAY AND THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC COLD FRONT HAS PASSED KUNV IN THE PAST HALF HOUR AND EXTENDS
FROM 30W KELN THROUGH KAOO SOUTHWARD TO KCBE. TEMPS IN THE LOWER
50S QUICKLY FALL BACK THROUGH THE 40S AND INTO THE UPPER 30S
BEHIND THE FRONT. NO UPSTREAM CHANGEOVER TO SNOW TO SPEAK OF AS
RAIN SHOWERS ARE STILL BEING REPORTED IN EASTERN OHIO. THE HIGHEST
TERRAIN OF THE WEST CENTRAL MOUNTAINS AND NORTHWEST MOUNTAINS
SHOULD SEE A BRIEF CHANGEOVER LATER THIS EVENING...AS PER KELZ
THIS HOUR...AND WE ARE STILL EXPECTING A COATING OF SNOW ON THOSE
HIGHER RIDGES. ELSEWHERE..NO ACCUMS ARE EXPECTED.
COLDER AIR EVENTUALLY WORKS IN OVERNIGHT...IMPACTING NW MTNS
FIRST...BUT WILL TAKE A GOOD PORTION OF THE OVERNIGHT TO REACH THE
LOWER SUSQ. AIR STILL NOT FORMIDABLE FOR DECEMBER THOUGH...AS
THESE READINGS REMAIN WELL ABOVE NORMAL FOR THIS TIME OF YEAR.
HIGH PRESSURE BEGINS TO BUILD IN LATE TONIGHT INTO TUE AS
CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING FOR MOST...POSS TUE
AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
23Z SFC ANALYSIS SHOWS A COLD FRONT BISECTING PA...RUNNING FROM
ELM SOUTHWARD THRU UNV AND JST. SHIFTING WINDS TO THE NW BEHIND
THE FRONT WILL CAUSE LINGERING MOISTURE TO ASCEND THE
ALLEGHENIES...BRINGING CONTINUED -SRHA AND IFR CIGS AT JST THRU
AT LEAST MIDNIGHT. LATEST RUC SOUNDINGS SUGGEST A CHANGEOVER TO SNOW AT
BFD BY ARND 01Z...WITH IFR CIGS/VSBYS LIKELY THERE ALSO THRU AT
LEAST MIDNIGHT.
FURTHER EAST...LOW LVL STABLE AIR MASS PERSISTS ACROSS THE SUSQ
VALLEY...WHERE LOW CIGS/FOG ARE REPORTED AT 23Z. HOWEVER...PASSAGE
OF COLD FRONT /ARND 01Z AT IPT AND 03Z AT MDT AND LNS/ WILL BRING
A WSHIFT TO THE NW WITH RAPIDLY IMPROVING CONDS.
LINGERING MVFR CIGS AND SCT -SHSN MAY PERSIST FROM MIDNIGHT THRU
MIDDAY TUE AT BFD/JST...WHILE DOWNSLOPING NW FLOW LIKELY BRINGS A
RETURN TO VFR CONDS EAST OF THE MTNS.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
706 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL TRAVERSE THE REGION LATE TODAY AND TONIGHT. WET
WEATHER WILL CONTINUE INTO THIS EVENING...THEN COLDER AND DRIER
CONDITIONS MOVE IN FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LIGHT RAIN AND DRIZZLE AHEAD OF APPROACHING COLD FRONT WILL
CONTINUE THROUGH THE AFTERNOON AND INTO THIS EVENING. SHARP YET
SLOW MOVING COLD FRONT FOR LATE AFTERNOON/EVENING WILL BRING A
WIND SHIFT TO THE WEST AND A FEW HOURS AFTER THAT PRECIP SHOULD
SHUT DOWN FOR MOST LOCATIONS /ABOUT 03-06Z/. EXCEPTION WILL BE
HIGHER TERRAIN OF THE WEST...WHERE PRECIP WILL LINGER AS SNOW
SHOWERS TONIGHT - LIKELY PRODUCING A COATING OF SNOW. COLDER AIR
EVENTUALLY WORKS IN OVERNIGHT...IMPACTING NW MTNS FIRST...BUT WILL
TAKE A GOOD PORTION OF THE OVERNIGHT TO REACH THE LOWER SUSQ. AIR
STILL NOT FORMIDABLE FOR DECEMBER THOUGH...AS THESE READINGS
REMAIN WELL ABOVE NORMAL FOR THIS TIME OF YEAR.
HIGH PRESSURE BEGINS TO BUILD IN LATE TONIGHT INTO TUE AS
CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING FOR MOST...POSS TUE
AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
23Z SFC ANALYSIS SHOWS A COLD FRONT BISECTING PA...RUNNING FROM
ELM SOUTHWARD THRU UNV AND JST. SHIFTING WINDS TO THE NW BEHIND
THE FRONT WILL CAUSE LINGERING MOISTURE TO ASCEND THE
ALLEGHENIES...BRINGING CONTINUED -SRHA AND IFR CIGS AT JST THRU
AT LEAST MIDNIGHT. LATEST RUC SOUNDINGS SUGGEST A CHANGEOVER TO SNOW AT
BFD BY ARND 01Z...WITH IFR CIGS/VSBYS LIKELY THERE ALSO THRU AT
LEAST MIDNIGHT.
FURTHER EAST...LOW LVL STABLE AIR MASS PERSISTS ACROSS THE SUSQ
VALLEY...WHERE LOW CIGS/FOG ARE REPORTED AT 23Z. HOWEVER...PASSAGE
OF COLD FRONT /ARND 01Z AT IPT AND 03Z AT MDT AND LNS/ WILL BRING
A WSHIFT TO THE NW WITH RAPIDLY IMPROVING CONDS.
LINGERING MVFR CIGS AND SCT -SHSN MAY PERSIST FROM MIDNIGHT THRU
MIDDAY TUE AT BFD/JST...WHILE DOWNSLOPING NW FLOW LIKELY BRINGS A
RETURN TO VFR CONDS EAST OF THE MTNS.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1004 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MAKE ITS WAY ACROSS THE CAROLINAS TODAY
AND REACHING THE COAST ON TUESDAY. COOLER HIGH PRESSURE BUILDS IN
BEHIND THE FRONT AND PERSISTS THROUGH THE END OF THE WORK WEEK.
ANOTHER FRONTAL SYSTEM IS EXPECTED TO APPROACH THE NORTH CAROLINA
MOUNTAINS LATER IN THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
930 PM UPDATE...THE OVERNIGHT FORECAST REMAINS GENERALLY ON TRACK.
THE SHOWERS ACTIVITY OVER SE ZONES HAS DECREASE CONSIDERABLY OVER
THE LAST COUPLE OF HOURS AND POPS HAVE BEEN UPDATED ACCORDINGLY. THE
LATEST RAP AND NAM INDICATE THAT A SURFACE COLD FRONT CURRENTLY OVER
TN/NC BORDER WILL GRADUALLY MOVE SE ACROSS OUR CWA THROUGH OVERNIGHT
HOURS AND OFF TO OUR SOUTH AND EAST BY EARLY TUES MORNING. THE
LATEST RAP SUGGESTS LIGHT PRECIP RESPONSE OVER NC PIEDMONT BY
DAYBREAK AS THE FRONT MOVES THROUGH BUT THE NAM KEEPS THE AREA DRY.
SO DUE TO THE UNCERTAINTY...POPS REMAIN ON THE LOW SIDE. WINDS WILL
VEER FROM SW TO NW/N DURING THE FROPA.
.PREVIOUS DISCUSSION...
A COUPLE LOW TOPPED CONVECTIVE LINE SEGMENTS HAVE MOVED INTO NE GA
AND THE WRN UPSTATE. THE STRUCTURE OF THE CELLS ISN/T BAD
CONSIDERING THAT THE CAPE OVER THE REGION IS ONLY RUNNING AROUND 100
J/KG. THEREFORE THERE IS A PRETTY GOOD CHANCE THAT THE CONVECTION
WILL HOLD TOGETHER AT LEAST ACROSS THE UPSTATE...AND POSSIBLY INTO
THE WRN NC PIEDMONT AND FOOTHILLS. 0-3KM BULK SHEAR IS BETWEEN 40-50
KTS ACROSS THE LINE...WHICH WOULD CERTAINLY SUPPORT A FEW DAMAGING
WIND GUSTS. AND THERE IS A SMALL CHANCE OF A QLCS TORNADO...THOUGH
THE CELLS OVER CENTRAL AND NRN GA HAVE NOT HAD VERY STRONG
ROTATIONAL COUPLETS SO FAR THIS AFTERNOON. THE CONVECTION IS
DEVELOPING WELL AHEAD OF THE SFC COLD FRONT. AS THE CONVECTION IS
MOVING NE AT 45 KTS...IT SHOULD CROSS A GOOD BIT OF THE FORECAST
AREA BY 23 UTC. THERE COULD BE A LITTLE DEVELOPMENT ALONG THE MAIN
SFC COLD FRONT...BUT THE GREATEST MODEL INSTABILITY...AROUND 200
J/JG...IS ALONG THIS LEADING AREA OF CONVECTION AS IT CROSSES THE
UPSTATE OVER THE NEXT FEW HOURS. THE CONVECTION WILL ALSO REQUIRE
INCREASING POPS TO CATEGORICAL LEVELS FOR A FEW HOURS ACROSS NE
GA...THE UPSTATE AND EVEN THE I-77 CORRIDOR. LATER THIS EVENING
ACTIVITY WILL DIMINISH TO JUST PATCHY LIGHT RAIN AND SHOWERS.
STRATUS IS EXPECTED TO BECOME WIDESPREAD AGAIN LATER TONIGHT AS WELL.
ON TUESDAY THE FRONT WILL STALL NEAR THE COAST. CONDITIONS SHOULD
CLEAR OUT INITIALLY...BUT MID AND HIGH CLOUDS WILL BE ON THE
INCREASE LATE IN THE DAY A SHORT WAVE INCREASES UPPER DIVERGENCE
ACROSS THE SE STATE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 215 PM MONDAY...USING A BLEND OF MOS GUIDANCE...LOW
TEMPERATURES ON WEDNESDAY MORNING ARE FORECAST TO RANGE FROM THE
U20S TO L30S ACROSS THE NC MTNS TO THE L40S ACROSS THE PIEDMONT.
CLOUD COVER AND PRECIPITATION CHANCES SHOULD INCREASE THROUGH THE
MORNING HOURS AS A BAND OF JET DIVERGENCE AND SYNOPTIC SCALE FORCING
INCREASES ACROSS THE PIEDMONT. FORECAST SOUNDINGS INDICATE THAT
FREEZING LEVEL WILL RANGE BETWEEN 5 TO 10 KFT AROUND SUNRISE
WEDNESDAY. GIVEN THE FORECAST SFC TEMPERATURES AND LLVL TEMPERATURE
PROFILES...IT APPEARS THAT PRECIP WILL FALL AS RAIN. WEDNESDAY
AFTERNOON AND EVENING...THE AXIS OF THE H5 SHORT WAVE WILL RIPPLE
ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. H5 TO H7 QG VERTICAL
VELOCITIES AHEAD OF THE FEATURE...PEAKING ACROSS THE CWA DURING THE
DAYLIGHT HOURS. I WILL INCREASE POPS EAST OF I-85 INTO THE CHC
RANGE...WITH 50 POPS EAST OF CLT. COVERAGE SHOULD STEADILY SHIFT
EAST WEDNESDAY NIGHT AS THE SHORT WAVE AXIS PASSES OVERHEAD. GIVEN
THE THICK CLOUD COVER AND RAINFALL POTENTIAL...HIGH TEMPERATURES
WILL REMAIN LIMITED TO THE U40S ACROSS THE MTNS TO THE L50S EAST.
ON THURSDAY...H5 HEIGHTS WILL RISE IN ADVANCE OF AN APPROACHING
RIDGE. AT THE SFC...THE CENTER OF A LARGE AREA OF HIGH PRESSURE
WILL BUILD ACROSS THE SOUTHERN APPALACHIANS. SUBSIDENCE IN BETWEEN THE
PASSING S/W AND BUILDING RIDGE SHOULD RESULT IN NEARLY CLEAR SKY
CONDITIONS. MORNING TEMPERATURES ON THURSDAY SHOULD RANGE WITHIN A
COUPLE OF DEGREES OF NORMAL. HIGH TEMPERATURES ARE FORECAST TO RANGE
FROM THE MID 50S ACROSS THE MTNS TO THE U50S EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 1 PM MONDAY...I WILL USE A BLEND OF THE GFS AND ECMWF
THROUGH THE EXTENDED PERIOD. FAVOR WILL BE GIVEN TO THE ECMWF FOR
DAYS 6 AND 7.
FRIDAY AND SATURDAY...BOTH SOLUTIONS INDICATE THAT A LONGWAVE RIDGE
WILL RIPPLE ACROSS THE SOUTHEAST U.S. AS THE CENTER OF A 1028 MB
HIGH REMAINS OVER THE REGION. IT APPEARS THAT SKY COVER WILL REMAIN
MOSTLY CLEAR ON FRIDAY...WITH INCREASING HIGH CLOUDS ON SATURDAY AS
THE RIDGE AXIS SHIFTS EAST OF THE AREA. THE COMBINATION OF THE
MINIMAL SKY COVER...LIGHT WINDS...AND DRY AIR SHOULD PROVIDE GOOD
RADIATIONAL COOLING FRI AND SAT MORNINGS. MIN TEMPERATURES FRIDAY
MORNING MAY RANGE FROM THE MID 20S ACROSS THE MTNS TO THE L30S
EAST...WARMING TO AROUND NORMAL SATURDAY MORNING. HIGH TEMPERATURES
ON BOTH DAYS SHOULD RANGE WITHIN 3 TO 5 DEGREES OF NORMAL.
SUNDAY AND MONDAY...THE ECMWF INDICATES THAT A MID LEVEL LOW AND AN
ASSOCIATED SHORT WAVE WILL TRACK ACROSS THE GREAT LAKES AND NEW
ENGLAND...FOLLOWED BY SFC LOW AND COLD FRONT. ACROSS THE SOUTHERN
APPALACHIAN REGION WILL LIKELY SEE THE PASSAGE OF THE COLD FRONT
DURING THE DAYLIGHT HOURS ON SUNDAY. ON MONDAY...AS SHORT WAVE
ORIGINATING OVER THE RIO GRANDE VALLEY IS EXPECTED TO REACH THE
SOUTHERN APPALACHIAN REGION. AS THE MID LEVEL FEATURE APPROACHES...A
FRONTAL WAVE MAY DEVELOP AND SUPPORT THE FORMATION OF SHRA ACROSS
THE PIEDMONT AND FOOTHILL AREAS.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AT CLT AND ELSEWHERE...THE SHOWER ACTIVITY HAS DECREASED
CONSIDERABLY IN COVERAGE OVER THE PAST COUPLE OF HOURS AND ONLY
AREAS OF LIGHT SHOWERS WERE OCCURRING ACROSS PORTIONS OF SC
PIEDMONT. THESE SHOWERS ARE EXPECTED TO TAPER OFF BY MIDNIGHT. MVFR
TO LOW VFR CEILINGS WILL CONTINUE BEFORE LOWERING INTO THE IFR
CATEGORY BY MID NIGHT...THOUGH THE EXACT TIMING REMAINS A BIT
UNCERTAIN AT THIS TIME. WINDS WILL VEER FROM SW TO NW AS A SURFACE
COLD FRONT CURRENTLY OVER NORTHERN NC MOUNTAINS CONTINUES TO MOVE SE
THROUGH OVERNIGHT HOURS. THE TIMING OF FROPA AT KAVL WILL BE AROUND
02Z...AROUND 08Z FOR KGMU/KGSP/KHKY/KCLT AND 10Z FOR KAND. IFR
CEILING OVERNIGHT WILL LIFT TO VFR LEVEL BY LATE TUE MORNING. N/NE
WINDS WILL PREVAIL FOR ALL TAF SITES ON TUESDAY.
OUTLOOK...A COLD FRONT WILL PUSH E OF THE REGION EARLY TUESDAY
MORNING. THE FORECAST REMAINS UNCERTAIN THROUGH MID WEEK AS THE
FRONTAL MOISTURE MAY STALL JUST E OF THE AREA AND RETURN WWD AS THE
NEXT WAVE APPROACHES WEDNESDAY. CONDITIONS WILL IMPROVE FOR SEVERAL
DAYS AS HIGH PRESSURE BUILDS IN.
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...PAT
NEAR TERM...JOH/MCAVOY
SHORT TERM...NED
LONG TERM...NED
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
551 PM CST MON DEC 10 2012
.UPDATE...
UPDATE TO INCREASE CLOUD COVER OVER THE EASTERN HALF OF THE
FORECAST AREA THIS EVENING.
&&
.DISCUSSION...
LATEST SATELLITE IMAGERY AS OF 23Z INDICATED LOWER LEVEL
STRATOCUMULUS CLOUD DECK FILLING IN ACROSS THE EASTERN HALF OF THE
FORECAST AREA AND SLOW TO ERODE FROM THE WEST. LATEST VAD WIND
PROFILER FROM KPAH SHOWS WINDS AROUND 4KFT FROM THE NORTH WHICH
MAY SERVE TO LOCK IN LOW LEVEL MOISTURE LONGER THAN EARLIER
ANTICIPATED AND INDICATED ON LATEST MODEL GUIDANCE. HAVE INCREASED
CLOUD COVER ACROSS MOST AREAS ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS EVENING AND SLOWLY CLEAR FROM WEST TO EAST AFTER 06Z.
SKIES SHOULD EVENTUALLY BECOME MOSTLY CLEAR AREA WIDE BY SUNRISE AS
MUCH DRIER LOW LEVEL AIR MASS FINALLY ADVECTS INTO THE REGION.
ALSO LOW TEMPERATURES HAVE BEEN ADJUSTED UPWARDS A FEW DEGREES
OVER EASTERN SECTIONS TO REFLECT ADDED CLOUD COVER. STILL
EXPECTING A COLD NIGHT REGARDLESS OF THE SKY COVER AS STRONG COLD
AIR ADVECTION CONTINUES OVER THE REGION.
UPDATED GRIDS AND ZONES WILL BE SENT SHORTLY.
JLH
&&
.PREV DISCUSSION... /ISSUED 344 PM CST MON DEC 10 2012/
DISCUSSION...
LOW AND MIDLEVEL CLOUDS WERE RAPIDLY DISSIPATING ACROSS THE
MIDSOUTH. NORTHWEST SURFACE WINDS PREVAILED...AROUND THE EASTERN
PERIPHERY OF AN ARCTIC SURFACE PRESSURE RIDGE CENTERED OVER
OKLAHOMA. THIS PRESSURE RIDGE WILL LIFT INTO THE LOWER MS AND OHIO
RIVER VALLEYS ON TUESDAY...PROVIDING LIGHT WINDS AND PRIME
NOCTURNAL RADITIONAL COOLING CONDITIONS THROUGH THURSDAY.
THE LATTER HALF OF THE WEEK WILL SEE LOW LEVEL SOUTHERLY FLOW
RETURN UNDER RIDGING ALOFT. BEST FEED OF GULF MOISTURE WILL REMAIN
OVER TX AND THE SOUTHERN PLAINS ON FRIDAY. THIS LOW LEVEL MOISTURE
AXIS WILLS SHIFT EASTWARD INTO THE MIDSOUTH... AHEAD OF A COMPACT
CLOSED UPPER LOW LIFTING INTO THE MID MS RIVER VALLEY. A TRAILING
COLD FRONT AND MIDLEVEL TROF AXIS WILL PROVIDE A CHANCE OF RAIN
OVER THE MIDSOUTH ON SATURDAY.
THE ECMWF HAS BEEN CONSISTENT IN BRINGING A DEEPER CLOSED LOW
ACROSS THE SOUTHERN PLAINS NEXT MONDAY...AND INTO THE MIDSOUTH ON
TUESDAY. GIVEN THE MUCH GREATER RUN TO RUN CONSISTENCY COMPARED TO
THE GFS...HAVE BASED DAYS 7 AND 8 ON THE ECMWF MODEL.
PWB
&&
.AVIATION...
18Z TAF CYCLE
CIGS ARE LIFTING AS A DRY SLOT MOVES IN FROM THE WEST. HOWEVER...THERE
ARE AN ABUNDANCE OF LOW CLOUDS OVER MISSOURI THAT WILL BEGIN TO
ROTATE INTO THE CWA AFTER 22-23Z. THE RUC KEEPS LOW CLOUDS OVER
THE AREA FOR MUCH OF THE OVERNIGHT PERIOD WITH POSSIBLE CLEARING
BEGINNING AFTER MIDNIGHT ACROSS NE ARKANSAS. THE NAM HAS DRY AIR
FILTERING IN DUE TO THE HIGH PRESSURE BUILDING INTO THE REGION AND
ESSENTIALLY ERODES THE LOW CLOUDS. THUS VFR CONDITIONS WOULD
PREVAIL IF THE NAM IS CORRECT. TOUGH FORECAST AND WITH THIS PACKAGE WILL
LEAN TOWARD THE RUC BUT NOT VERY CONFIDENT. NORTHWEST WINDS OF
10-15 KTS WITH HIGHER GUSTS WILL BEGIN TO DIE DOWN THIS AFTERNOON.
AFTER 00Z...NORTHERLY WINDS AROUND 5 KTS CAN BE EXPECTED.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 25 44 28 51 / 0 0 0 0
MKL 26 43 21 50 / 0 0 0 0
JBR 22 43 23 50 / 0 0 0 0
TUP 28 48 26 52 / 0 0 0 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
858 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA OVERNIGHT...EXITING OFF
THE COAST TUESDAY MORNING. HIGH PRESSURE WILL BE THE DOMINATING
WEATHER FEATURE ACROSS OUR AREA THROUGH THE REMAINDER OF THE WORK
WEEK...ALTHOUGH A LOW PRESSURE SYSTEM DEVELOPING OFF THE CAROLINA
COAST MAY SPREAD LIGHT PRECIPITATION INTO THE PIEDMONTS ON
WEDNESDAY EVENING AND THURSDAY MORNING. ANOTHER COLD FRONT IS
EXPECTED TO ENTER THE AREA SUNDAY MORNING.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 815 PM EST MONDAY...
COLD FRONT NOW FROM NEAR LWB DOWN THE I-77 CORRIDOR SHOULD SHIFT
SE ACROSS THE BLUE RIDGE BY MIDNIGHT AND THE PIEDMONT DURING THE
EARLY MORNING HOURS. AN ADDITIONAL BAND OR TWO OF SHOWERS ALONG
THE FRONT SHOULD ALSO KEEP PERIODIC RAINFALL GOING ESPCLY VA/WVA
MOUNTAINS DURING THE NEXT COUPLE OF HOURS BEFORE THE FRONT PASSES
AND BETTER DOWNSLOPE KICKS IN. THIS WILL CONTINUE TO LIMIT MUCH
SHRA FROM GETTING OUT EAST UNTIL PERHAPS WHEN THE FRONT SLOWS UP
OVER THE SE LATE. THIS MOST IN LINE WITH THE LATEST RAP SOLUTION
WHICH KEEPS SHRA OVER THE WEST UNTIL AROUND MIDNIGHT WHILE
SHIFTING SOME LIGHTER PRECIP INTO THE PIEDMONT SHORTLY THEREAFTER.
THUS WILL CONTINUE HIGH POPS FOR LOW QPF SHRA WEST FOR A BIT
LONGER AND SOME CHANCE POPS OUT EAST UNTIL THE FRONT PASSES LATER
ON. QUICK SURGE IN COLD ADVECTION WEST SHOULD QUICKLY DROP TEMPS
THRU THE 40S AND INTO THE 30S ESPCLY SE WVA CTYS WHERE WILL BE A
RACE BETWEEN DEPARTING DEEP MOISTURE AND COLD AIR FOR SNOW
SHOWERS. LATEST NAM SOUNDINGS SHOW RATHER SHALLOW MOISTURE LATE
TONIGHT SO STAYING WITH ONLY CHANCE POPS AND MAINLY ELEVATION
-SHSN LATE.
QUICK SHOT OF GUSTY NW WINDS WITH THE FRONT SHOULD LEVEL OFF
OVERNIGHT AS ONLY WEAK SUBSIDENCE UNDER A DIMINISHING JET ALOFT.
LOWERED TEMPS SOME WEST GIVEN UPSTREAM OBS AND STRONG GRADIENT OF
COLD ADVECTION ALONG THE SLOWING 85H FRONT NEAR THE BLUE RIDGE
LATE.
BY SUNRISE TUESDAY...PRECIPITATION WILL BE LIMITED TO LEFT OVER
RAIN SHOWERS ACROSS THE PIEDMONT IN THE WAKE OF THE FRONT...AS
WELL AS A FEW SHOWERS LINGERING ACROSS THE MOUNTAINS. DEPENDING ON
QUICKLY THE SUB-FREEZING AIR BUILDS IN...MAY SEE CHANGE OVER TO
SNOW FOR A SHORT PERIOD OF TIME FOR ELEVATIONS ABOVE 2500
FEET...HOWEVER THE WINDOW OF OPPORTUNITY APPEARS SMALL AS HIGH
PRESSURE WILL SCOUR OUT RESIDUAL MOISTURE BY LATE MORNING...WITH
CLOUDS GRADUALLY BREAKING UP THROUGH THE DAY. AS SUCH...EXPECT NO
MORE THAN A DUSTING IN AREAS WHERE SNOWFALL DOES OCCUR.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 206 PM EST MONDAY...
TUESDAY EVENING...A COLD FRONT WILL BE NEAR THE ATLANTIC COAST. A
DISTURBANCE IN THE GULF OF MEXICO WILL MOVE NORTHEAST ALONG THIS
FRONT. AS THIS FEATURE APPROACHES THE CAROLINAS...THE FRONT WILL
BUCKLE NORTH TO NEAR THE FALL LINE OF SC AND NC. AS THE FEATURE
REACHES THE CAROLINAS...GOOD ONSHORE FLOW FROM THE ATLANTIC WILL BE
ADVECTED CYCLONICALLY AROUND THE LOW WITH THE NORTHERN EXTENT OF
THIS MOISTURE SKIRTING THE FAR SOUTHEAST PART OF THE FORECAST AREA
STARTING LATE TUESDAY NIGHT AND ENDING WEDNESDAY AFTERNOON.
BY WEDNESDAY NIGHT INTO THURSDAY...HIGH PRESSURE WILL MOVER THE
REGION WITH THE RIDGE AXIS SHIFTING EAST OF THE REGION BY THURSDAY
NIGHT. THIS WILL BEGIN A PERIOD OF TEMPERATURES WARMING TO ABOVE
NORMAL TEMPERATURES AGAIN AS THE PREVAILING FLOW BECOMES SOUTHWEST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 PM EST MONDAY...
HIGH PRESSURE OVER PENNSYLVANIA WILL BUILD SOUTH INTO OUR REGION
FRIDAY...WITH A FLAT UPPER LEVEL RIDGE ALONG EAST COAST. HIGH
TEMPERATURES WILL RUN 5 TO 10 ABOVE NORMAL FRIDAY. THE SURFACE RIDGE
BEGINS TO SHIFT OFF THE EAST COAST FRIDAY NIGHT AS UPPER TROUGH IN
THE WEST SLIDES EAST INTO THE SOUTHERN PLAINS SATURDAY. FLOWS
BECOMES MORE SOUTHWEST AS THIS SYSTEM ADVANCES INTO THE UPPER
MIDWEST WITH A COLD FRONT TRAILING BACK TO THE GULF COAST FROM THE
PARENT LOW. MEDIUM GUIDANCE CONTINUES TO HAVE TIMING DIFFERENCE WITH
MOISTURE ASSOCIATED WITH THE COLD FRONT AND ITS MOVEMENT...WITH THE
ECMWF FASTER...DEEP WITH THE LOW CENTER AND HIGHER WITH THE QPF
COMPARED TO THE GFS. WITH THE TREND OF THE ECMWF FROM 00Z TO 12Z
SLOWER...ELECTED TO LEAN TOWARD THE SLOWER GFS SOLUTION. PLAYED
HIGHS ON SATURDAY TOWARDS THE MILDER MOS GUIDE WITH SOUTHSIDE
WARMING INTO THE LOWER 60S. THE COLD FRONT WILL TRAVEL EAST
APPROACHING THE MOUNTAINS SATURDAY NIGHT AND MOVE ACROSS OUR REGION
SUNDAY. THE FRONTAL BOUNDARY WILL PUSH INTO THE ATLANTIC OCEAN ON
SUNDAY NIGHT WITH HIGH PRESSURE BUILDING ACROSS WEST VIRGINIA IN ITS
WAKE. ON MONDAY...AS SHORTWAVE IS EXPECTED TO REACH THE SOUTHERN
APPALACHIAN REGION. AS THE MID LEVEL FEATURE APPROACHES...A FRONTAL
WAVE MAY DEVELOP AND SUPPORT THE CHC OF SHRA IN THE SOUTH.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
AS OF 600 PM EST MONDAY...
COLD FRONT JUST WEST OF KBLF WILL CONTINUE TO MOVE EAST...REACHING
THE BLUE RIDGE AROUND 9 PM...BEFORE SLIDING ACROSS THE PIEDMONT
TOWARD MIDNIGHT. SHOWERS APPEAR LIGHT ENOUGH TO KEEP VFR VSBYS FOR
THE MOST PART THIS EVENING WHILE CEILINGS ONLY LOOK TO SLOWLY
FALL INTO MVFR LEVELS ACROSS SE WVA EARLY ON...AND THEN POINTS
EAST TO KROA BY 9/10 PM. THINK EASTERN LOCATIONS WILL STAY WITH
VFR CIGS FOR THE MOST PART BUT COULD ALSO FALL INTO MVFR BY
MIDNIGHT AS THE FRONT NEARS. OTRW EXPECT CLOUD BASES TO LOWER INTO
IFR OVER THE WEST IN THE WAKE OF THE FRONT IN SE WVA DUE TO
UPSLOPE FLOW AND PERHAPS KBCB/KROA ONCE THE SHOWERS TAPER. COULD
ALSO SEE DENSE FOG ALSO DEVELOP AROUND KBLF WITH IFR/MVFR VSBYS
POSSIBLE OVERNIGHT ALTHOUGH CONFIDENCE LOW. LIGHT TO MODERATE
TURBULENCE IS POSSIBLE ACROSS THE AREA DUE TO 15KT TO 20KT CROSS
BARRIER FLOW BEHIND THE FRONT.
CONDITIONS WILL IMPROVE ON TUESDAY AS HIGH PRESSURE BEGINS TO
SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE MOUNTAINS
TUESDAY WILL RESULT IN SPOTTY MVFR CONDITIONS AND THE POSSIBILITY
OF MORNING SNOW SHOWERS WITH THE ARRIVAL OF COLDER AIR. SOME LOWER
CIGS LIKEY TO ALSO LINGER OVER THE SE BEFORE ALL RETURN TO VFR BY
AFTERNOON IF NOT SOONER.
AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE COASTAL
CAROLINAS WEDNESDAY BEFORE MOVING OUT TO SEA THURSDAY. THIS SYSTEM
MAY CLIP SE PORTIONS OF THE AREA INCLUDING DAN/LYH WITH POTENTIAL
-RA AND PERHAPS MVFR CIGS LATER TUESDAY NIGHT INTO MIDDAY
WEDNESDAY. VFR CONDITIONS WILL FINALLY RETURN AREAWIDE LATER
WEDNESDAY AND THEN CONTINUE INTO SATURDAY AS WEAK HIGH PRESSURE
BUILDS IN.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH/NF
SHORT TERM...DS
LONG TERM...KK
AVIATION...JH/NF/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
153 PM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EST SUNDAY...
LATEST SURFACE OBSERVATIONS INDICATE THE COLD FRONT IS SITUATED
JUST NORTHWEST OF OUR AREA THIS MORNING...STRETCHING THROUGH THE
CENTRAL PORTIONS OF KENTUCKY AND WEST VIRGINIA INTO NORTHERN
VIRGINIA. THE IMMEDIATE CONCERN IS A BAND OF SHOWER ACTIVITY
MAKING ITS WAY ACROSS KENTUCKY...RIDING ALONG THE FRONT. EXPECT
THESE SHOWERS TO SKIRT OUR MOUNTAIN EMPIRE COUNTIES BEGINNING
AROUND NOON...AND CONTINUE MOVING NORTHEAST ACROSS THE ALLEGHANY
HIGHLANDS THROUGH THE AFTERNOON BEFORE MOVING AWAY. SMALLER...MORE
SUBTLE DISTURBANCES PASSING ACROSS THE AREA WILL TRIGGER
SPOTTIER...LESS ORGANIZED SHOWER ACTIVITY ELSEWHERE THROUGH THE
DAY AS WELL.
AS THE DISTURBANCE TRIGGERING THESE SHOWERS MOVES NORTH...IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO THE FOOTHILLS. OUR LOCAL WRF
AND RAP FORECAST MODELS INDICATED THE WEDGE REACHING THE ROANOKE
RIVER BY THE END OF THE DAY...BEFORE ADVANCING SLOWLY BACK NORTH
TONIGHT AS A WARM FRONT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 130 PM EST SUNDAY...
SURFACE OBSERVATIONS INDICATE THAT WHILE VISIBILITIES HAVE
IMPROVED WITH AFTERNOON HEATING...AREAS OF LIFR TO MVFR CEILINGS
REMAIN ACROSS THE AREA...INTERMIXED WITH VFR CEILINGS. ALSO
CONCERNED WITH TWO AREAS OF SHOWER ACTIVITY...A SMALL AREA THAT
WILL BRIEFLY AFFECT DAN BETWEEN 19Z AND 21Z...AND A MUCH LARGER
AREA STRETCHING FROM EASTERN TENNESSEE THROUGH NORTHERN WEST
VIRGINIA...MOVING TO THE NORTHEAST ALONG A COLD FRONT SITUATED
ACROSS THE AREA. EAST OF THE MOUNTAINS...ALSO OBSERVING THE SAME
COLD FRONT BUILD SOUTHWARD ACROSS THE PIEDMONTS AS A BACKDOOR
FRONT...ALREADY HAVING PASSED THROUGH LYH...AS EVIDENCED BY MVFR
STRATOCU MOVING IN FROM THE NORTHEAST.
WHILE THE MAJORITY OF THE SHOWER ACTIVITY WILL REMAIN WEST OF THE
AREA THIS AFTERNOON...EXPECT SOME OF THESE SHOWERS TO SPILL OVER
THE MOUNTAINS...AFFECTING BLF AND LWB DURING EARLY TO MID
EVENING...BEFORE PUSHING AWAY FROM THE AREA BEFORE MIDNIGHT
MONDAY.
EXPECT MVFR FOG MOST LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR
THE BACKDOOR FRONT ADVANCES WEST...EVEN ROA MAY HAVE MVFR FOG.
ALSO CONCERNED WITH LOW LEVEL WIND SHEAR DUE TO STRENGTHENING LOW
LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE FROM THE
SOUTHWEST AT 30 TO 40 KNOTS...AND HAVE THEREFORE MENTIONED IN THE
TAFS. EXPECT THE BACKDOOR FRONT TO LIFT NORTHWARD AGAIN SHORTLY
BEFORE SUNRISE AS A DEEP LOW PRESSURE SYSTEM PASSES ACROSS THE
GREAT LAKES.
ON MONDAY AFTERNOON...A STRONG COLD FRONT WILL ENTER THE FORECAST
AREA...PASSING ACROSS BLF AND LWB AOA 10/20Z...AND MOVING ACROSS
DAN AND LYH AOA 11/03Z. EXPECT GUSTY NORTHWEST WINDS BEHIND THE
FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR CONDITIONS WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1025 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EST SUNDAY...
LATEST SURFACE OBSERVATIONS INDICATE THE COLD FRONT IS SITUATED
JUST NORTHWEST OF OUR AREA THIS MORNING...STRETCHING THROUGH THE
CENTRAL PORTIONS OF KENTUCKY AND WEST VIRGINIA INTO NORTHERN
VIRGINIA. THE IMMEDIATE CONCERN IS A BAND OF SHOWER ACTIVITY
MAKING ITS WAY ACROSS KENTUCKY...RIDING ALONG THE FRONT. EXPECT
THESE SHOWERS TO SKIRT OUR MOUNTAIN EMPIRE COUNTIES BEGINNING
AROUND NOON...AND CONTINUE MOVING NORTHEAST ACROSS THE ALLEGHANY
HIGHLANDS THROUGH THE AFTERNOON BEFORE MOVING AWAY. SMALLER...MORE
SUBTLE DISTURBANCES PASSING ACROSS THE AREA WILL TRIGGER
SPOTTIER...LESS ORGANIZED SHOWER ACTIVITY ELSEWHERE THROUGH THE
DAY AS WELL.
AS THE DISTURBANCE TRIGGERING THESE SHOWERS MOVES NORTH...IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO THE FOOTHILLS. OUR LOCAL WRF
AND RAP FORECAST MODELS INDICATED THE WEDGE REACHING THE ROANOKE
RIVER BY THE END OF THE DAY...BEFORE ADVANCING SLOWLY BACK NORTH
TONIGHT AS A WARM FRONT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM EST SUNDAY...
SCATTERED SHOWERS WILL MOVE NORTHEAST AWAY FROM KLWB BY 14Z/9AM
THIS MORNING. COVERAGE OF IFR TO LIFR CEILINGS IS VARIABLE THIS
MORNING. MODERATE CONFIDENCE THAT ANY LOW STRATUS WILL LIFT TO AT
LEAST MVFR LEVELS BY 18Z/1PM.
COLD FRONT WAS OVER NORTHERN VIRGINIA. EXPECT BOUNDARY TO DROP
SOUTH THROUGH THE FOOTHILLS TODAY. IFR TO LIFR CLOUDS NORTH OF THE
FRONT TONIGHT AT LYH AND POSSIBLE ROA. EXPECT MVFR FOG MOST
LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR WEDGE ADVANCES BUT
EVEN KROA MAY HAVE MVFR FOG.
CHANCE OF SHOWERS WILL CONTINUE TODAY WITH MORE WIDESPREAD
PRECIPITATION MOVING INTO THE MOUNTAINS BY MONDAY MORNING. FRONT
LIFTS BACK NORTH EARLY MONDAY THEN VERY STRONG COLD FRONT PUSHES
THROUGH FROM THE WEST MONDAY EVENING.
HAVE ADDED LOW LEVEL WINDS SHEAR TO THE TAFS TONIGHT DUE TO
INCREASING LOW LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE
FROM THE SOUTHWEST AT 30 TO 40 KNOTS. EXPECT GUSTY NORTHWEST
WINDS BEHIND THE FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
714 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EST SATURDAY...
SCATTERED TO NUMEROUS SHOWERS...ASSOCIATED WITH A SHORT WAVE
MOVING THROUGH WEST VIRGINIA...WERE TRACKING NORTHEAST ACROSS THE
WESTERN COUNTY WARNING AREA EARLY THIS MORNING. WATER VAPOR LOOP
SHOWED ANOTHER SHORT WAVE JUST ENTERING WESTERN KENTUCKY AND
TENNESSEE WHICH MODELS TAKE ALONG THE SAME TRACK. THIS SHOULD
BRING MORE SHOWERS TO THE WESTERN COUNTY WARNING AREA THIS
AFTERNOON.
SCATTERED SHOWERS WERE ALSO MOVING THROUGH SOUTHSIDE VIRGINIA.
ONCE THESE SHOWERS MOVE THROUGH THIS MORNING THE CHANCE OF
PRECIPITATION WILL BE LOWER IN THIS PART OF THE FORECAST AREA FOR
THE REST OF THE DAY.
THE COLD FRONT EXTENDED FRONT NEW JERSEY TO CENTRAL KENTUCKY.
ONCE THE WEST VIRGINIA SHORT WAVE MOVES SLIGHTLY FARTHER
NORTH...THE FRONT WILL ADVANCE SOUTH INTO THE FOOTHILLS THIS
MORNING. LOCAL WRK AND LATEST RAP SHOWED THE WEDGE REACHING THE
ROANOKE RIVER BY THE END OF THE DAY BEFORE ADVANCING SLOWLY BACK
NORTH TONIGHT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM EST SUNDAY...
SCATTERED SHOWERS WILL MOVE NORTHEAST AWAY FROM KLWB BY 14Z/9AM
THIS MORNING. COVERAGE OF IFR TO LIFR CEILINGS IS VARIABLE THIS
MORNING. MODERATE CONFIDENCE THAT ANY LOW STRATUS WILL LIFT TO AT
LEAST MVFR LEVELS BY 18Z/1PM.
COLD FRONT WAS OVER NORTHERN VIRGINIA. EXPECT BOUNDARY TO DROP
SOUTH THROUGH THE FOOTHILLS TODAY. IFR TO LIFR CLOUDS NORTH OF THE
FRONT TONIGHT AT LYH AND POSSIBLE ROA. EXPECT MVFR FOG MOST
LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR WEDGE ADVANCES BUT
EVEN KROA MAY HAVE MVFR FOG.
CHANCE OF SHOWERS WILL CONTINUE TODAY WITH MORE WIDESPREAD
PRECIPITATION MOVING INTO THE MOUNTAINS BY MONDAY MORNING. FRONT
LIFTS BACK NORTH EARLY MONDAY THEN VERY STRONG COLD FRONT PUSHES
THROUGH FROM THE WEST MONDAY EVENING.
HAVE ADDED LOW LEVEL WINDS SHEAR TO THE TAFS TONIGHT DUE TO
INCREASING LOW LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE
FROM THE SOUTHWEST AT 30 TO 40 KNOTS. EXPECT GUSTY NORTHWEST
WINDS BEHIND THE FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
455 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EST SATURDAY...
SCATTERED TO NUMEROUS SHOWERS...ASSOCIATED WITH A SHORT WAVE
MOVING THROUGH WEST VIRGINIA...WERE TRACKING NORTHEAST ACROSS THE
WESTERN COUNTY WARNING AREA EARLY THIS MORNING. WATER VAPOR LOOP
SHOWED ANOTHER SHORT WAVE JUST ENTERING WESTERN KENTUCKY AND
TENNESSEE WHICH MODELS TAKE ALONG THE SAME TRACK. THIS SHOULD
BRING MORE SHOWERS TO THE WESTERN COUNTY WARNING AREA THIS
AFTERNOON.
SCATTERED SHOWERS WERE ALSO MOVING THROUGH SOUTHSIDE VIRGINIA.
ONCE THESE SHOWERS MOVE THROUGH THIS MORNING THE CHANCE OF
PRECIPITATION WILL BE LOWER IN THIS PART OF THE FORECAST AREA FOR
THE REST OF THE DAY.
THE COLD FRONT EXTENDED FRONT NEW JERSEY TO CENTRAL KENTUCKY.
ONCE THE WEST VIRGINIA SHORT WAVE MOVES SLIGHTLY FARTHER
NORTH...THE FRONT WILL ADVANCE SOUTH INTO THE FOOTHILLS THIS
MORNING. LOCAL WRK AND LATEST RAP SHOWED THE WEDGE REACHING THE
ROANOKE RIVER BY THE END OF THE DAY BEFORE ADVANCING SLOWLY BACK
NORTH TONIGHT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS OF 1115 PM EST SATURDAY...
BROKEN BAND OF SHOWERS WILL CONTINUE TO AFFECT KLWB AND PERHAPS
KBLF OVERNIGHT WITH A SLOW DOWNTURN TO MVFR THERE WITH MAINLY VFR
PREVAILING ELSW BEFORE FOG DEVELOPS SHORTLY AFTER MIDNIGHT.
MOISTURE WILL THEN DEEPEN TOWARD DAWN SUNDAY AS A COLD FRONT TO
THE NW BACKDOORS SOUTH DOWN EAST OF THE MOUNTAINS BY MORNING. THIS
SHOULD AID LIFT SOME ESPCLY AFTER MIDNIGHT WITH CIGS LOWERING TO
MVFR MOST SPOTS THEN DROPPING TO IFR OR WORSE IN STRATUS/FOG
ESPCLY KROA AND POINTS EAST DURING THE EARLY MORNING HOURS OF
SUNDAY. HOWEVER IF SKIES STAY CLEAR LONGER OVERNIGHT THEN COULD
ALSO SEE POOR FLYING CONDITIONS DEVELOP SOONER DUE TO FOG AND
STRATUS FORMATION. OTRW EARLIER CLOUD COVER MAY LIMIT LOWER CIGS
ACROSS THE SE WVA SITES EXCEPT AT KLWB WHERE RAINFALL SHOULD AID
FOG FORMATION AND POSSIBLY A PERIOD OF IFR BY DAYBREAK.
THE IFR TO MVFR CEILINGS...IN CONJUNCTION WITH THE WEDGE OUT EAST
WILL LIKELY BE SLOW TO EXIT SUNDAY MORNING ESPCLY IF DRIZZLE
DEVELOPS AND HELPS HOLD LOWER CIGS IN LONGER. ALSO POTENTIAL FOR
LIFT TO RESULT IN CONTINUED SCATTERED SHRA ACROSS THE WEST INTO
SUNDAY AFTERNOON SO LEFT IN MENTION FROM KBCB WESTWARD. CONDITIONS
MAY IMPROVE SLIGHTLY BY SUNDAY AFTERNOON TO MVFR OR EVEN VFR
ESPCLY WEST OF THE BLUE RIDGE WITH ONLY A GRADUAL LIFTING OF
CIGS/VSBYS FROM SOUTH TO NORTH EAST OF THE BLUE RIDGE. MAY EVEN
SEE KLYH/KROA STAY MVFR OR WORSE AT TIMES UNTIL LATE SUNDAY. AGAIN
EXPECT MORE FOG AND LOW CLOUDS TO REDEVELOP ESPCLY EAST SUNDAY
NIGHT BEFORE THINGS PERHAPS SCOUR OUT TO HIGH END MVFR OR VFR
MONDAY MORNING. THEN A STRONGER COLD FRONT PUSHES THROUGH FROM
WEST MONDAY NIGHT...BRINGING MVFR TO IFR CONDITIONS ONCE AGAIN
WITH POSSIBLY HEAVIER SHOWERS. NORTHWEST CROSS BARRIER WINDS
BEHIND THE COLD FRONT WILL LIKELY RESULT IN STRONG MECHANICAL
TURBULENCE FOR MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR SHOULD MAKE A GRADUAL RETURN BY TUESDAY NIGHT INTO WEDNESDAY
AND THEN LINGER THRU LATE NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS/JH/SK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
725 PM CST MON DEC 10 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
725 PM CST MON DEC 10 2012
725 PM UPDATE...LATEST RADAR IMAGERY...WEB CAM HERE AT OUR OFFICE
AS WELL AS THE 01Z OBSERVATION FROM KOVS ALL SHOWING AN INCREASE
IN SNOW DEVELOPMENT IN THE STRATUS DECK THAT ENCOMPASSES MOST
LOCATIONS ALONG AND EAST OF THE MISSISSIPPI RIVER. BEST GUESS IS
THAT THERE IS SOME INCREASING TURBULENCE IN THE STRATUS DECK AHEAD
OF THE HIGH PRESSURE RIDGE BUILDING INTO THE AREA...AND GIVEN THAT
THE STRATUS DECK LIES IN THE DENDRITIC GROWTH ZONE PER 00Z GRB/DVN
SOUNDINGS...IT DOES NOT TAKE MUCH TO GET SNOW GOING. OVER THE LAST
TWO HOURS...THE MOTION OF THE SNOW ON RADAR IS FOLLOWING AN
EASTWARD PROGRESSION AROUND 11 KT. HAVE USED THIS MOTION IN
SHOWING AN EXTRAPOLATION OF THE CURRENT RADAR IMAGERY FOR THE
PRECIPITATION CHANCE FORECAST THROUGH THE NIGHT. REGARDING THE
CHANCES...GIVING THAT WE ARE DEALING WITH DENDRITES AND THE
FORCING IS WEAK AT BEST...IT IS LIKELY WE MAY NOT SEE MUCH LIQUID
EQUIVALENT QPF OUT OF THIS. HOWEVER...A FEW TENTHS OF AN INCH OF
SNOW COULD ACCUMULATE. SINCE THE PRECIPITATION CHANCE DEFINITION
IS FOR A 0.01 OF LIQUID EQUIVALENT...ONLY HAVE 20 TO 30 PERCENT
CHANCES AT THE MOMENT WITH UP TO A HALF INCH OF SNOWFALL
ACCUMULATION.
PREVIOUS DISCUSSION ISSUED AT 332 PM...
AT 3 PM...LOW CLOUDS PERSISTED ACROSS MUCH OF THE FORECAST AREA.
THIS MOISTURE WAS TRAPPED BELOW A SUBSIDENCE INVERSION. THE
VISIBLE AND FOG PRODUCT /11-3.9 MICRON CHANNEL/ SHOW THAT THE
CLOUDS ARE STARTING TO BREAK UP IN THE DODGE CENTER...AUSTIN...
CHARLES CITY AREAS. THE RAP SEEMS TO BE HANDLING THIS THE BEST.
THEY SHOW THAT A NARROW AREA OF CLEARING WILL MOVE EAST ACROSS
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THIS EVENING. THIS AREA
REMAINS NARROW DUE TO ANOTHER AREA OF CLOUDS MOVING INTO THE
REGION FROM THE DAKOTAS. THIS CLEARING WILL ALLOW A RAPID DROP IN
TEMPERATURES DUE TO FRESH SNOW AND LIGHT WINDS...AND THEN THE
TEMPERATURES WILL RISE AS THE CLOUDS MOVE BACK INTO THE AREA.
ON TUESDAY AFTERNOON AND EVENING...A SHORT WAVE TROUGH WILL MOVE
ACROSS THE AREA. AHEAD OF THIS WAVE...MODERATE 270 TO 280K
ISENTROPIC LEADS TO SATURATION UP TO 775 MB. HOWEVER AS THE WAVE
IS MOVING THROUGH THE REGION...THERE IS VERY LITTLE OMEGA AND THE
LOW LEVEL LAPSE RATES ARE NOT THAT STEEP. AS A RESULT...NOT
EXPECTING ANY ACCUMULATING SNOW. HOWEVER WOULD NOT BE TOO
SURPRISED TO SEE A FEW FLURRIES. SINCE THIS WAVE IS CURRENTLY NOT
PRODUCING ANYTHING UPSTREAM AND THE FORCING AND MOISTURE LOOKS
SIMILAR...DID NOT INCLUDE THEM IN THE FORECAST AT THIS TIME.
ON WEDNESDAY...THE 500 MB FLOW BECOMES ZONAL. THIS KEEPS THE NEXT
2 SHORT WAVE TROUGHS /WEDNESDAY AND THURSDAY/ NEAR THE
U.S./CANADIAN BORDER. BOTH OF THESE SYSTEMS WILL DRAW WARMER AIR
INTO THE REGION. WHILE THE MODELS WERE PUSHING MUCH OF THE AREA
INTO THE 35 TO 45 DEGREE RANGE FOR HIGH TEMPERATURES...LOWERED THEM
A COUPLE OF DEGREES DUE TO THE SNOW PACK.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
332 PM CST MON DEC 10 2012
FROM FRIDAY NIGHT INTO SATURDAY NIGHT...THE MAIN CONCERN WILL BE THE
TRACK OF A SYSTEM MOVING OUT OF THE SOUTHWEST UNITED STATES. AS
THIS SYSTEM MOVES NORTHEAST IT WILL BRING WARM AIR AND GULF
MOISTURE WITH IT. PRECIPITABLE WATER VALUES CLIMB ANYWHERE FROM
150 TO 200 PERCENT OF NORMAL. BOTH THE ECMWF AND GEM HAVE A MUCH
FURTHER NORTH TRACK THAN THE GFS. AS A RESULT...THEY BRING RAIN
INTO SOUTHWEST WISCONSIN AND NORTHEAST IOWA...AND A WINTRY MIX OF
SNOW AND SLEET OR ALL SNOW ACROSS THE REMAINDER OF THE AREA FROM
FRIDAY NIGHT INTO SATURDAY...AND THE PRECIPITATION CHANGES OVER TO
ALL SNOW BEFORE IT ENDS ON SATURDAY NIGHT. MEANWHILE THE GFS IS
ABOUT 6 HOURS SLOWER AND IT ALSO IS FAR ENOUGH SOUTH THAT ONLY THE
AREAS SOUTH OF THE INTERSTATE 90 CORRIDOR WOULD SEE SNOW FROM THIS
SYSTEM. THE GFS ENSEMBLE CONTINUES TO SHOW A WIDESPREAD OF
SOLUTIONS. A FEW OF THEM ARE SIMILAR TO THE ECMWF AND GEM...BUT
THERE ARE ALSO A FEW THAT NO PRECIPITATION AT ALL. OVERALL THE
ECMWF HAS BEEN THE MOST CONSISTENT...SO TRENDED THE FORECAST
TOWARD IT.
&&
.AVIATION...TONIGHT AND TUESDAY
521 PM CST MON DEC 10 2012
A RIDGE OF HIGH PRESSURE CENTERED JUST WEST OF I-35 IN MINNESOTA
AND IOWA WILL SLIDE EAST ACROSS THE TAF SITES THIS EVENING. EXPECT
WINDS TURNING SOUTHWESTERLY AND EVEN SOUTHERLY TO CONTINUE
PUSHING THE STRATUS DECK NEAR/OVER THE TAF SITES EASTWARD. KRST
HAS ALREADY GONE VFR AND KLSE SHOULD DO THE SAME IN THE NEXT 1 TO
2 HOURS. VFR CONDITIONS ARE EXPECTED TO PERSIST THEN UNTIL A LOW
PRESSURE TROUGH CURRENTLY OVER THE EASTERN DAKOTAS MOVES THROUGH
LATE TUESDAY MORNING. IN ITS WAKE...MODELS ARE SUGGESTING LOW
STRATUS OF THE MVFR OR PERHAPS EVEN IFR TO MOVE IN. CURRENTLY
THERE HAS BEEN VERY LITTLE IN THE WAY OF MVFR STRATUS AND EVEN
SOME CLEAR POCKETS. WITH DIURNAL COOLING TONIGHT...PERHAPS THERE
IS AN OPPORTUNITY TO BUILD AN MVFR STRATUS DECK. AS A RESULT...
HAVE INCLUDED BROKEN 2500-3000 FT CEILINGS AFTER 17/18Z AT THE TAF
SITES. ALSO CANNOT RULE OUT SOME FLURRIES OR LIGHT SNOW WITH THE
TROUGH SEEING SOME OF THIS UPSTREAM...BUT CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IT IN THE TAFS. WINDS SHOULD VEER MORE
WESTERLY AND INCREASE A LITTLE TOWARDS 10-15 KT IN THE WAKE OF THE
TROUGH PASSAGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
332 PM CST MON DEC 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
521 PM CST MON DEC 10 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
332 PM CST MON DEC 10 2012
AT 3 PM...LOW CLOUDS PERSISTED ACROSS MUCH OF THE FORECAST AREA.
THIS MOISTURE WAS TRAPPED BELOW A SUBSIDENCE INVERSION. THE
VISIBLE AND FOG PRODUCT /11-3.9 MICRON CHANNEL/ SHOW THAT THE
CLOUDS ARE STARTING TO BREAK UP IN THE DODGE CENTER...AUSTIN...
CHARLES CITY AREAS. THE RAP SEEMS TO BE HANDLING THIS THE BEST.
THEY SHOW THAT A NARROW AREA OF CLEARING WILL MOVE EAST ACROSS
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THIS EVENING. THIS AREA
REMAINS NARROW DUE TO ANOTHER AREA OF CLOUDS MOVING INTO THE
REGION FROM THE DAKOTAS. THIS CLEARING WILL ALLOW A RAPID DROP IN
TEMPERATURES DUE TO FRESH SNOW AND LIGHT WINDS...AND THEN THE
TEMPERATURES WILL RISE AS THE CLOUDS MOVE BACK INTO THE AREA.
ON TUESDAY AFTERNOON AND EVENING...A SHORT WAVE TROUGH WILL MOVE
ACROSS THE AREA. AHEAD OF THIS WAVE...MODERATE 270 TO 280K
ISENTROPIC LEADS TO SATURATION UP TO 775 MB. HOWEVER AS THE WAVE
IS MOVING THROUGH THE REGION...THERE IS VERY LITTLE OMEGA AND THE
LOW LEVEL LAPSE RATES ARE NOT THAT STEEP. AS A RESULT...NOT
EXPECTING ANY ACCUMULATING SNOW. HOWEVER WOULD NOT BE TOO
SURPRISED TO SEE A FEW FLURRIES. SINCE THIS WAVE IS CURRENTLY NOT
PRODUCING ANYTHING UPSTREAM AND THE FORCING AND MOISTURE LOOKS
SIMILAR...DID NOT INCLUDE THEM IN THE FORECAST AT THIS TIME.
ON WEDNESDAY...THE 500 MB FLOW BECOMES ZONAL. THIS KEEPS THE NEXT
2 SHORT WAVE TROUGHS /WEDNESDAY AND THURSDAY/ NEAR THE
U.S./CANADIAN BORDER. BOTH OF THESE SYSTEMS WILL DRAW WARMER AIR
INTO THE REGION. WHILE THE MODELS WERE PUSHING MUCH OF THE AREA
INTO THE 35 TO 45 DEGREE RANGE FOR HIGH TEMPERATURES...LOWERED THEM
A COUPLE OF DEGREES DUE TO THE SNOW PACK.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
332 PM CST MON DEC 10 2012
FROM FRIDAY NIGHT INTO SATURDAY NIGHT...THE MAIN CONCERN WILL BE THE
TRACK OF A SYSTEM MOVING OUT OF THE SOUTHWEST UNITED STATES. AS
THIS SYSTEM MOVES NORTHEAST IT WILL BRING WARM AIR AND GULF
MOISTURE WITH IT. PRECIPITABLE WATER VALUES CLIMB ANYWHERE FROM
150 TO 200 PERCENT OF NORMAL. BOTH THE ECMWF AND GEM HAVE A MUCH
FURTHER NORTH TRACK THAN THE GFS. AS A RESULT...THEY BRING RAIN
INTO SOUTHWEST WISCONSIN AND NORTHEAST IOWA...AND A WINTRY MIX OF
SNOW AND SLEET OR ALL SNOW ACROSS THE REMAINDER OF THE AREA FROM
FRIDAY NIGHT INTO SATURDAY...AND THE PRECIPITATION CHANGES OVER TO
ALL SNOW BEFORE IT ENDS ON SATURDAY NIGHT. MEANWHILE THE GFS IS
ABOUT 6 HOURS SLOWER AND IT ALSO IS FAR ENOUGH SOUTH THAT ONLY THE
AREAS SOUTH OF THE INTERSTATE 90 CORRIDOR WOULD SEE SNOW FROM THIS
SYSTEM. THE GFS ENSEMBLE CONTINUES TO SHOW A WIDESPREAD OF
SOLUTIONS. A FEW OF THEM ARE SIMILAR TO THE ECMWF AND GEM...BUT
THERE ARE ALSO A FEW THAT NO PRECIPITATION AT ALL. OVERALL THE
ECMWF HAS BEEN THE MOST CONSISTENT...SO TRENDED THE FORECAST
TOWARD IT.
&&
.AVIATION...TONIGHT AND TUESDAY
521 PM CST MON DEC 10 2012
A RIDGE OF HIGH PRESSURE CENTERED JUST WEST OF I-35 IN MINNESOTA
AND IOWA WILL SLIDE EAST ACROSS THE TAF SITES THIS EVENING. EXPECT
WINDS TURNING SOUTHWESTERLY AND EVEN SOUTHERLY TO CONTINUE
PUSHING THE STRATUS DECK NEAR/OVER THE TAF SITES EASTWARD. KRST
HAS ALREADY GONE VFR AND KLSE SHOULD DO THE SAME IN THE NEXT 1 TO
2 HOURS. VFR CONDITIONS ARE EXPECTED TO PERSIST THEN UNTIL A LOW
PRESSURE TROUGH CURRENTLY OVER THE EASTERN DAKOTAS MOVES THROUGH
LATE TUESDAY MORNING. IN ITS WAKE...MODELS ARE SUGGESTING LOW
STRATUS OF THE MVFR OR PERHAPS EVEN IFR TO MOVE IN. CURRENTLY
THERE HAS BEEN VERY LITTLE IN THE WAY OF MVFR STRATUS AND EVEN
SOME CLEAR POCKETS. WITH DIURNAL COOLING TONIGHT...PERHAPS THERE
IS AN OPPORTUNITY TO BUILD AN MVFR STRATUS DECK. AS A RESULT...
HAVE INCLUDED BROKEN 2500-3000 FT CEILINGS AFTER 17/18Z AT THE TAF
SITES. ALSO CANNOT RULE OUT SOME FLURRIES OR LIGHT SNOW WITH THE
TROUGH SEEING SOME OF THIS UPSTREAM...BUT CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IT IN THE TAFS. WINDS SHOULD VEER MORE
WESTERLY AND INCREASE A LITTLE TOWARDS 10-15 KT IN THE WAKE OF THE
TROUGH PASSAGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
332 PM CST MON DEC 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
928 PM MST MON DEC 10 2012
.UPDATE...IT APPEARS THAT THE NORTHERLY JET MOVING OVER THE STATE
FROM THE NORTHWEST IS GOING TO HAVE ENOUGH DYNAMICS UNDER ITS LEFT
EXIT REGION TO PRODUCE PERSISTENT LIGHT SNOW SHOWERS THROUGH MOST
OF THE NIGHT...EVEN ON THE PLAINS. WILL BE UPDATING THE FORECAST
TO INCLUDE A CHANCE OF SNOW THROUGH MIDNIGHT...THEN A SLIGHT
CHANCE OF SNOW DURING THE PRE-DAWN HOURS. THE SNOW MAY OR MAY NOT
EXTEND ALL THE WAY BACK TO THE FOOTHILLS...DEPENDING ON HOW MUCH
DOWNSLOPE DRYING WILL BE CONTAINED IN THE NORTHWEST WINDS FLOWING
OVER THE MOUNTAINS. MOUNTAIN AREAS PREVIOUSLY HAD SNOW FORECAST
THROUGH MOST OF THE NIGHT...SO NO CHANGES THERE. ACCUMULATIONS ON
THE PLAINS WILL BE LESS THAN AN INCH...AS IT WILL BE A VERY DRY
SNOW THAT IS FALLING.
&&
.AVIATION...WILL BE ADDING SNOW TO THE DENVER AREA TAFS THROUGH
09Z. BAND OF SNOWFALL IS WORKING ITS WAY SOUTHWARD FROM GREELEY AT
THE PRESENT TIME. LIGHT SNOW OR FLURRIES WILL LAST FOR A FEW
HOURS...BUT ACCUMULATIONS SHOULD BE LESS THAN AN INCH.
&&
.PREV DISCUSSION... /ISSUED 320 PM MST MON DEC 10 2012/
SHORT TERM...STILL DEALING WITH A MODERATE NORTHWEST FLOW PATTERN
ACROSS COLORADO AND STILL PLENTY OF MOISTURE UPSTREAM TO KEEP
LIGHT SNOW GOING IN THE MOUNTAINS. DEEPEST MOISTURE WILL BE UNTIL
MIDNIGHT AND THEN GRADUALLY MOISTURE DEPTH GETS MORE SHALLOW
DURING THE DAY ON TUESDAY. WILL KEEP LIKELY POPS IN THE MOUNTAINS
THROUGH EARLY TUESDAY THEN DIMINISHING LATE IN THE PERIOD. CROSS
SECTIONS INDICATE ANOTHER 2-4 INCHES IN THE MOUNTAINS TONIGHT AND
THEN ANOTHER INCH TUESDAY MORNING. AS FOR THE NORTHEAST
PLAINS...THE GUSTY NORTHWEST WINDS WILL DECREASE THIS EVENING AS
WINDS DECOUPLE FROM THE STRONGER FLOW ALOFT AND WEAK SURGE SHIFTS
WINDS A BIT MORE NORTHERLY. RUC AND GFS HINTS AT SOME LOW QPF
OVER PORTIONS OF THE PLAINS...ESPECIALLY OVER THE PALMER DIVIDE.
GIVEN THE NORTHERLY FLOW WILL KEEP A VERY LOW POP IN THOSE
LOCATIONS BUT NOT OVER THE FRONT RANGE. SKIES WILL CLEAR LATER
TONIGHT BEHIND THIS WEAK WAVE.
LONG TERM...UPPER TROF AXIS MOVES INTO CENTAL PLAINS TUESDAY
EVENING WITH MODERATE TO STRONG NORTHWEST FLOW ALOFT ACROSS
COLORADO. SUBSIDENCE MID LEVEL SUBSIDENCE TO SPREAD ACROSS AREA
WITH DECREASING MID LEVEL MOISTURE. WITH INCREASING WARM AIR
ADVECTION AND STABILITY...SHOULD SEE MOUNTAIN SNOW SHOWERS END
DURING THE EVENING. MODELS SHOW WEAK MOUNTAIN WAVE DEVELOPING
OVERNIGHT TUESDAY WITH CROSS MOUNTAIN FLOW INCREASING TO AROUND 50
KTS AT MOUNTAIN TOP INTO EARLY WEDNESDAY MORNING. SHOULD CONTINUE
TO BE GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS...THOUGH THE
STRONGEST WINDS APPEAR TO REMAIN ACROSS THE HIGHER RIDGES. SPEEDS
SHOULD REMAIN BELOW HIGH WIND CRITERIA. RIDGE AXIS TO MOVE ACROSS
THE STATE WEDNESDAY INTO THURSDAY WITH WESTERLY FLOW ALOFT
BECOMING MORE SOUTHWEST AS UPPER TROUGH MOVES INTO THE GREAT
BASIN. DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITH
TEMPERATURES EXPECTED TO WARM BACK TO SEASONAL NORMALS. FOR
FRIDAY...BOTH DGEX AND ECMWF SHOW UPPER TROUGH MOVING ACROSS
COLORADO WHILE GFS BRINGS TROUGH ACROSS THE STATE FRIDAY EVENING.
AT THIS TIME NOT SURE WHICH SOLUTIONS WILL BE CORRECT...BUT THERE
IS A GENERAL CONSENSUS OF MOISTURE INCREASING ACROSS COLORADO
ALONG WITH SOME MID LEVEL ASCENT. SHOULD BE ENOUGH FOR A CHANCE OF
MOUNTAIN SNOW. DGEX AND ECMWF ALSO GENERATE SOME LIGHT PRECIP
ACROSS SOUTHERN AND FAR EASTERN COLORADO LATE AFTERNOON AND
EVENING. WILL INCLUDE SOME LOW POPS FAR EASTERN ZONES TO ACCOUNT
FOR THIS WITH DRY CONDITIONS ELSEWHERE.
ON SATURDAY...FLOW ALOFT TO BECOME NORTHWEST AS UPPER TROUGH MOVES
ACROSS CENTRAL PLAINS. MODELS SHOW MAINLY DRY AIRMASS OVER
COLORADO...BUT STILL DECENT MOISTURE AND OROGRAPHICS ACROSS
MOUNTAINS TO KEEP SOME SNOW GOING. OTHERWISE DRY CONDITIONS TO
PREVAIL. FOR SUNDAY AND MONDAY...NORTHWEST FLOW ALOFT TO CONTINUE
ENOUGH OROGRAPHIC SUNDAY FOR A SLIGHT CHANCE OF MOUNTAIN SNOW. .
LATEST ECMWF HI RES MODEL HINTS AT A WEAK DISTURBANCE EMBEDDED IN
THE FLOW MOVING ACROSS THE STATE SUNDAY NIGHT AND MONDAY WHICH
MAY HELP INCREASE SNOW CHANCES ACROSS MOUNTAINS AND BRING A
PERHAPS A SLIGHT CHANCE OF SNOW THE THE PLAINS. LATEST DGEX AND
GFS KEEP THINGS DRY MONDAY. FOR NOW WILL LEAN TOWARD THE DRIER
SOLUTIONS OF THE DGEX AND GFS WITH A SLOW WARMING TREND.
AVIATION...NORTHWEST SURFACE WINDS AT 15-25KT HAVE SURFACED AT
BJC AND APA AND STILL TRYING TO DEVELOP AT KDEN. WILL KEEP THE
IDEA OF SOME BETTER MIXING WITH GUSTY WINDS TO MATERIALIZE AT DEN
FOR A SHORT TIME THROUGH 00Z. FOR TONIGHT A NON DESCRIPT SURFACE
PATTERN WITH A DISORGANIZED FRONT WHICH MAY KEEP SOME WEAK
NORTHERLY FLOW IN THE TERMINALS THROUGH MIDNIGHT BEFORE SLOWLY
RETURNING TO DRAINAGE WINDS LATER IN THE NIGHT. WITH THE MOISTURE
UPSTREAM MAY SEE SOME CEILINGS DIPPING INTO THE 6000-7000 FOOT AGL
RANGE AND MAYBE A BIT LOWER AT APA. WILL STILL KEEP TERMINALS DRY
EXCEPT A VCSH AT APA.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DANKERS
LONG TERM....D-L
AVIATION...RTG
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
243 AM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
THE FRONT WILL BE STALLED NEAR THE COAST TODAY. THE FRONT WILL BE
PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL SHORTWAVE TROUGH
OVER THE GULF OF MEXICO EARLY THIS MORNING SHOULD RESULT IN A
MOISTURE INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS
INCREASE. THERE MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE
POPS WITH THE GREATEST CHANCE IN THE SOUTHEAST PART. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
EXPECT A CONTINUED SERIES OF LOW PRESSURE SYSTEMS MOVING
NORTHEASTWARD ALONG THE STALLED FRONTAL ZONE. THE MODELS
GENERALLY SHOW DEEPER MOISTURE JUST EAST OF THE FORECAST AREA WITH
THE FARTHEST EXTENT WESTWARD WEDNESDAY AND WEDNESDAY NIGHT
ASSOCIATED WITH THE MAIN MID-LEVEL SHORTWAVE TROUGH. THE
NAM...GFS...AND ECMWF APPEAR TO INDICATE ENOUGH MOISTURE IN THE
EAST PART FOR LIKELY POPS WEDNESDAY OR WEDNESDAY NIGHT. THE
GUIDANCE CONSENSUS SUPPORTED POPS OF LIKELY EAST TO CHANCE WEST.
THERE WILL BE A TIGHT MOISTURE GRADIENT FROM WEST TO EAST AND THIS
MAKES FORECAST CONFIDENCE LOW. THE GUIDANCE TEMPERATURES APPEAR
TOO WARM WEDNESDAY BECAUSE OF A WEDGE PATTERN. OTHERWISE...USED
THE CONSENSUS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE LATEST GFS AND ECMWF AGREE SHOWING DRY RIDGING BECOMING
DOMINATE THURSDAY AND CONTINUING OVER THE AREA FRIDAY. THE MODELS
SHOW A MOISTURE INCREASE SATURDAY WITH A FRONT IN THE AREA SUNDAY.
THE GFS ENSEMBLE MEANS SUPPORT LOW POPS AT THIS TIME. EXPECT
TEMPERATURES ABOVE NORMAL PRIOR TO FRONTAL PASSAGE.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
COLD FRONT REMAINS JUST WEST OF THE TERMINALS BUT WILL PUSH EAST
DURING THE 06Z-12Z TIME FRAME. VFR CONDITIONS TO START THE
FORECAST BUT EXPECT MVFR CIGS TO ACCOMPANY THE FRONTAL ZONE AS IT
MOVES EAST ACROSS THE AREA. MVFR CIGS EXPECTED 09Z-15Z WITH
POSSIBLE IFR CIGS AGS/DNL. LIGHT WEST TO SOUTHWEST WINDS THROUGH
15Z THEN PICKING UP FROM THE WEST AROUND 5 TO 8 KNOTS. COLD FRONT
TO STALL EAST OF THE AREA TODAY AND EXPECT MID AND HIGH CLOUDS TO
CONTINUE TO PROVIDE A VFR CLOUD DECK THROUGH THE END OF THE
FORECAST PERIOD.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TUESDAY
NIGHT THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOWER END VFR CIGS TO PERSIST THROUGH THE EARLY MORNING HOURS.
* SOME LIGHT SNOW/FLURRIES POSSIBLY OVERNIGHT WITH MINIMAL VSBY
REDUCTIONS...AND POSSIBLY CIG REDUCTION TO MVFR.
* SOUTHWEST WINDS WILL GUST TO AROUND 20KT TUESDAY LATE MORNING
INTO THE AFTERNOON.
KREIN
//DISCUSSION...UPDATED 06Z...
A LINGERING LOWER END VFR ST/SC DECK HAS BEEN SLOW TO CLEAR THE
REGION UNDER CYCLONIC FLOW ALOFT. A WEAK SHORT WAVE CROSSING NRN
IL HAS HELPED GENERATE SOME -SHSN...WHICH HAVE BEEN MOST PREVALENT
OVER NCNTRL IL...WITH ANOTHER PATCH MOVING THROUGH NWRN IN...PER
LATEST RADAR TRENDS. EXPECT THAT THERE IS STILL SOME POTENTIAL FOR
SOME -SN/-SHSN UNTIL ARND 09Z WHEN THE SHORTWAVE WILL FINALLY MOVE
OFF TO THE EAST AND WEAK RIDGING WILL DEVELOP ALOFT. LATEST
SATELLITE IMAGERY SHOWS A BACK EDGE TO THE CLOUD DECK APPROACHING
THE MS RIVER AND SHOULD STEADILY PUSH EWD...LEADING TO MOSTLY
CLEAR SKIES SHORTLY BEFORE DAYBREAK.
WITH A LOW PRESSURE SYSTEM TRACKING EWD THROUGH SCNTRL CANADA AND
HIGH PRESSURE SETTING OVER THE OHIO VALLEY...WINDS WILL BECOME
SWLY THROUGH THE MORNING. WITH AMPLE SUNSHINE AIDING DEEP LAYER
MIXING AND A STRENGTHENING PRESSURE GRADIENT...THERE SHOULD BE
FREQUENT GUSTS TO ARND 20KT FROM LATE MORNING THROUGH SUNSET.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CIGS TONIGHT AND TIMING OF CLEARING.
* LOW TO MEDIUM CONFIDENCE IN -SN OVERNIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY THROUGH FRIDAY...VFR.
SATURDAY...RAIN LIKELY. IFR PROBABLE.
SUNDAY...MVFR CIGS LIKELY.
IZZI
&&
.MARINE...
313 PM CST
N AND NE WINDS WILL DIMINISH TONIGHT AS LOW PRESSURE IN SW QUEBEC
MOVES E TO THE GULF OF SAINT LAWRENCE OVERNIGHT ALLOWING HIGH
PRESSURE OVER ONTARIO TO DROP SSE TO THE LOWER GREAT LAKES. S AND
SW WINDS WILL BE ON THE INCREASE TUE AS THE HIGH MERGES WITH
ANOTHER HIGH PRESSURE RIDGE OVER THE SOUTHERN PLAINS...OZARKS AND
LOWER OH VALLEY. WINDS SLACKEN AGAIN OVERNIGHT TUE BEFORE
FRESHENING AGAIN DURING WED AS LOW PRESSURE IN THE NORTHERN HIGH
PLAINS ELONGATES ACROSS THE UPPER MIDWEST INTO ONTARIO BY THU.
WINDS MAY REACH GALE FORCE BY WED NIGHT ON NORTHERN LAKE MI...AND
PERSIST INTO THU. THE LOW PRESSURE TROUGH DROPS S ACROSS THE GREAT
LAKES FRI WHILE LOW PRESSURE DEEPENS AS IT MOVES E FROM THE
CENTRAL ROCKIES TO THE CENTRAL PLAINS FRI AND FRI NIGHT. THIS LOW
TURNS NE TO THE MID MS VALLEY SAT AND MOVES INTO THE UPPER GREAT
LAKES SAT NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
125 AM EST MON DEC 10 2012
.AVIATION... /06 UTC TAFS/
PRIMARY FOCUS ON DWINDLING LES EVENT. BACKED CLOUD BEARING LAYER
FLOW HAS SHUNTED PRIMARY BAND WELL NORTH OF KSBN ATTM. LESSER
MULTIPLE BANDS CONT TO SW...WITH BACK EDGE INTO NCNLT LA PORTE CO.
SHARP DECRS IN MSTR DEPTH/DWINDLING DENDRITIC GROWTH LAYER ALONG
WITH INCSRG DRY AIR ADVECTION WITHIN 925-850MB LYR TO FURTHER WEAKEN
REMNG LES BANDS THRU 08 UTC. MAINTAIN TEMPO IFR AT KSBN TIL THEN
WITH BRIEF THOUGH SIG HORIZONTAL VSBY LWRG IN 25-30 DBZ CELLS. WITH
DCRSD MSTR AND SUBSIDENCE /MID LVL HGHT RISES/ ANTICIPATE END TO
SPOTTY IFR CIGS ACRS NCNTL/NERN IN AS WELL BYND 08 UTC. INCRSD
SSWRLY FLOW BY MIDDAY INADVOF CLIPPER SYSTEM...THOUGH ANY PRECIP
ASSOCD SHOULD TUE NIGHT SHOULD HOLD N OF RGN.
&&
.UPDATE...
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO BE THE PRIMARY SHORT
TERM CONCERN. SFC TROUGH WHICH BROUGHT A PERIOD OF SNOW AND EVEN
SOME LIGHT RAIN TO NORTHERN SECTIONS OF FORECAST AREAS NOW APPEARS
TO EXTEND FROM A LINE FROM SOUTHERN LA PORE COUNTY EXTENDING
EASTWARD ALONG THE ROUTE 30 CORRIDOR. LIGHT SNOW PERSISTS ALONG
THIS CONVERGENCE AXIS WITH SNOWFALL AMOUNTS GENERALLY LESS THAN A
HALF INCH OBSERVED AS THIS AREA HAS DROPPED SOUTHWARD. LAKE EFFECT
SNOW SHOWERS HAVE INCREASED SIGNIFICANTLY OVER PAST TWO HOURS
ACROSS FAR EASTERN LAKE MICHIGAN WHERE THERMALLY INDUCED SFC
CONVERGENCE APPEARS TO BE AIDING IN FOCUSING LAKE EFFECT SNOW
SHOWERS. LAKE EFFECT PARAMETERS STILL APPEAR TO BE QUITE FAVORABLE
FOR A SHORT PERIOD OF MORE SIGNIFICANT LAKE EFFECT SNOW SHOWERS
ESPECIALLY IN THE 03Z-08Z TIMEFRAME...WHEN INVERSION HEIGHTS RISE
TO NEAR 7500 FT...AND LAKE INDUCED EQUILIBRIUM LEVELS REACH NEAR
13K FT. ORIENTATION OF THERMALLY INDUCED SFC TROUGH WOULD SUGGEST
THAT BERRIEN/WESTERN CASS COUNTY INLINE TO SEE MORE SIGNIFICANT
LAKE EFFECT SNOW SHOWERS...AND POSSIBLY EXTENDING INTO NORTH
CENTRAL/NORTHEAST PORTIONS OF LA PORTE COUNTY.
SECONDARY BAND ALSO APPEARS TO BE DEVELOPING WEST OF MICHIGAN CITY
WHICH APPEARS TO BE AIDED BY LARGER SCALE LOW LEVEL CONVERGENCE
FROM REMNANTS OF SLOW MOVING SFC TROUGH. LONGEVITY OF A FAVORABLE
WIND FIELD APPEARS MORE QUESTIONABLE WITH THIS BAND HOWEVER WITH
STRONGER CONVERGENCE LIKELY REMAINING ANCHORED CLOSER TO THE
EASTERN SHORELINE. GIVEN LINGERING UNCERTAINTIES AS TO HOW BANDING
WILL UNFOLD THE REMAINDER OF THE EVENING...HAVE MAINTAINED A
BROADBRUSH 1 TO 3 INCH MENTION IN FORECAST AND WILL HOLD OFF ON
ANY HEADLINES AT THIS TIME...ALTHOUGH IF HEADLINES ARE NEEDED IT
APPEARS AS THOUGH BERRIEN COUNTY WOULD HAVE A GREATER RISK AT
REACHING LOCALIZED ADVISORY LEVEL AMOUNTS. IT STILL APPEARS AS
THOUGH THERMAL CONVERGENCE SHOULD BEGIN TO BREAK DOWN AFTER
09Z...AS LARGE SCALE SYNOPTIC WINDS BEGIN TO FAVOR MORE WESTERLY
DIRECTIONS ALSO ACTING TO LIMIT FETCH AND LAKE SUPERIOR CONNECTION.
&&
.PREV DISCUSSION... /ISSUED 247 PM EST MON DEC 10 2012/
SHORT TERM...
DIFFICULT PD EARLY ON GIVEN SCOPE OF DVLPG LK RESPONSE. SFC TROUGH
ACRS NRN CONTS TO DROP SWD AND EMBOLDENING A BROADER RESPONSE
UNDERNEATH BALLOONING MID LVL MSTR PLUME. BRIEF PD OF FZDZ AND
PERHAPS SLEET AT ONSET BUT QUICKLY CHANGING OVR TO SHSN N-S TIMED
W/ARRIVAL OF LK MSTR ENTRAINMENT PLUME AND DEEPENING CAA WEDGE.
PRIMARY PROB THIS EVENING IS TEA KETTLE LK SETUP AND DENOTED QUITE
WELL IN RUC13 AND OTHER HIGHRES GUIDANCE. LK SP CONNECTION NOTED
THIS AFTN WITHIN FVRBLY VEERED LONG AXIS CYCLONIC FETCH AS SEEN IN
VIS IMAGERY AND SUSPECT LK CONVERGENCE ZONE WILL ABRUPTLY BLOSSOM
AFT SUNSET IN TANDEM W/MAXIMIZING LL THERMAL TROUGH OF WHICH MAY
LEAD TO A BRIEF PD OF SIG LK EFFECT SNOWFALL CNTRD THROUGH EXTREME
SW BERRIEN...NRN LAPORTE AND WRN ST JOE COUNTIES. TEMPTED TO
CONSIDER AN ADVISORY BUT GIVEN UPSTREAM LK DVLPMNTS HAVE YET TO
PLAY THEIR CARD...CONFIDENCE LACKING. WILL CONT TO MONITOR AND
PASS CONCERNS ONWARD.
OTRWS LG SCALE SFC RIDGE WILL BUILD ALG THE APPALACHIAN SPINE
THROUGH THE END OF THE PD AS WK SECONDARY SYS DIPS THROUGH SRN
ONTARIO. LL FLW BACKS ABRUPTLY LT TONIGHT TO WRLY W/DWINDLING LK
EFFECT LIFTING OUT BFR BACKING FURTHER TO SWRLY ON TUE. THIS WILL
YIELD SW-NE CLRG W/SOME INSOLATION HELPING TO BOOST TEMPS A BIT
WARMER THAN TDA.
LONG TERM...WEDNESDAY THROUGH MONDAY.
ENERGY CURRENTLY IN THE GULF OF ALASKA WILL DIG ALONG THE PACIFIC
COAST THROUGH THE UPCOMING WEEK...REACHING CALIFORNIA BY THURSDAY.
THIS WILL ALLOW FOR INCREASING HGTS WITH A SEMI ZONAL FLOW TO SET UP
THROUGH FRIDAY. TEMPS ARE EXPECTED TO MODERATE TO ABOVE NORMAL
LEVELS IN THE 40S.
LEE SIDE CYCLOGENESIS WILL TAKE PLACE STARTING LATE FRIDAY WITH THE
SYSTEM EJECTING TOWARDS THE GREAT LAKES. MODELS VARYING SOMEWHAT ON
TIMING AND OVERALL TRACK...BUT SEEM TO POINT TOWARDS THE FORECAST
AREA BEING ON THE WARM SIDE ONCE AGAIN...YIELDING RAIN CHANCES FOR
THE WEEKEND FOLLOWED BY A MIXTURE OF RAIN/SNOW IN ITS WAKE. PREV
GRIDS HAD DECENT HANDLE ON TRENDS. ONLY CHANGES MADE WAS TO BREAK UP
WITH SOMEWHAT MORE DETAIL TO TRY TO ADD SOME TIMING TO BETTER
CHANCES OF PRECIP. QUICK SHOT OF COLD AIR WILL ARRIVE BEHIND THE
SYSTEM...BUT NOTHING SUBSTANTIALLY COLDER WITH A RETURN TO NEAR OR
SLIGHTLY BELOW NORMAL READINGS.
ENERGIZED PATTERN WILL CONTINUE OUTSIDE THE LONG TERM PERIOD WITH
NEXT SYSTEM ALREADY TAKING SHAPE OVER TEXAS BY MONDAY NIGHT. ECMWF
OVER THE PAST SEVERAL RUNS HAS HINTED THAT THIS COULD BRING A DECENT
SHOT OF ACCUMULATING SNOWFALL TO THE REGION BOTH IN ADVANCE OF THE
SYSTEM AND WITH WHAT COULD BE A PERSISTENT DEFORMATION ZONE AS THE
LOW CUTS OFF SOMEWHERE IN THE EASTERN GREAT LAKES. PLENTY OF TIME TO
WATCH AT THIS POINT CONSIDERING STILL A WAYS TO GO.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...FISHER
UPDATE...MARSILI
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
217 AM MST TUE DEC 11 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
04Z WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED BROAD TROUGHING
ACROSS MUCH OF THE CONUS. PV ANALYSIS INDICATED SHORT WAVE TROUGH
MOVING INTO NORTHERN COLORADO...WITH AREA OF LIGHT SNOW OCCURRING TO
THE SOUTHWEST OF MAIN ANOMALY. AT THE SFC...HIGH PRESSURE WAS
CENTERED ACROSS THE AREA WITH AREA OF VERY LOW DEWPOINTS NOTED
ACROSS SOUTHWEST KANSAS...WITH HIGHER DEWPOINTS MOVING INTO THE AREA
FROM THE NORTH. 00Z RAOBS UPSTREAM OF THE AREA INDICATED MUCH
HIGHER LAPSE RATES THAN 24 HOURS AGO...AND WHILE LAPSE RATES WERE
NOT DRY ADIABATIC THEY WOULD SUPPORT CONDITIONAL INSTABILITY OR
NEUTRAL CONDITIONS SHOULD SATURATION OCCUR.
MAIN FORECAST CONCERNS WILL BE LIGHT SNOW POTENTIAL THROUGH THE
EARLY MORNING HOURS FOLLOWED BUY RISING TEMPS AND FIRE WX POTENTIAL
THROUGH THURSDAY.
TODAY...INITIAL CONCERN WILL BE AREA OF LIGHT SNOW TO THE WEST OF THE
AREA OCCURRING AHEAD OF WEAK PV ANOMALY. RUC SEEMS TO BE ONLY NEAR
TERM MODEL THAT HAS CAUGHT ON TO THIS...ALTHOUGH PRECIP AREA LOOKS
TOO LARGE FOR WHAT IS OCCURRING. FROM WHAT I CAN TELL FROM THE POINT
SOUNDINGS...FORCED ASCENT REALLY CONCENTRATED IN THE LOW LEVELS
AROUND THE DGZ WHICH IS LOCATED AROUND H7. GIVEN THE OVERALL PATTERN
THINK PRECIP THREAT WILL CONTINUE UNTIL H8-H7 FLOW BECOMES MORE
NORTHWESTERLY LEADING TO WEAK CAA AFTER 09Z. THERE IS SOME
INSTABILITY TO WORK WITH...BUT BASED ON LATEST RADAR TRENDS SEEMS
DOUBTFUL THAT SIG SNOW AMOUNTS WOULD OCCUR IN CWA. OTHERWISE...THINK
PRECIP CHANCES WILL END QUICKLY WITH SKIES CLEARING THROUGH THE DAY
AS LARGE SCALE SUBSIDENCE MOVES OVER THE AREA BEHIND TROUGH.
TONIGHT-TOMORROW...SHORT WAVE RIDGE WILL AMPLIFY OVER THE AREA
DURING THE PERIOD BRINGING DRY CONDITIONS AND A FEW HIGH CLOUDS.
OVERALL DO NOT THINK CLOUDS WILL HAVE A BIG IMPACT ON
TEMPS...ALTHOUGH AM A LITTLE CONCERNED THAT STRONG H3 FLOW
PERPENDICULAR TO ROCKIES MAY CREATE AN ENHANCED AREA OF CIRRUS DURING
THE AFTERNOON. DESPITE THE LOW LEVEL WESTERLY FLOW...THE POTENTIAL
FOR HIGH CLOUD COVER AND LATEST ROUND OF OPERATIONAL DATA HAS
TEMPERED MY CONFIDENCE IN A SIG WARM UP SOMEWHAT AND HAVE LOWERED
HIGHS A FEW DEGREES ACROSS EASTERN CWA. FOR THE AREAS THAT DO MIX
OUT/WARM STRONGLY UPPER 50S AND AFTERNOON HUMIDITIES AROUND 15
PERCENT LIKELY. WILL HAVE NEAR CRITICAL FIRE WX CONDITIONS IN THIS
AREA...BUT NOT A LOT OF SUPPORT FOR STRONG WINDS EVEN WITH
DEVELOPING LEE TROUGH. CANNOT RULE OUT RED FLAG CONDITIONS
DEVELOPING...BUT CONFIDENCE TOO LOW IN WINDS MATERIALIZING TO ISSUE
WATCH ATTM.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
WED NIGHT-THUR NIGHT...SHORT WAVE RIDGE WILL BE PRIMARY INFLUENCE OF
WEATHER ACROSS THE CWA AS FLOW ALOFT BECOMES MORE AMPLIFIED IN
RESPONSE TO WEST COAST TROUGH. GIVEN THE PATTERN AND VERTICAL
MOISTURE/STABILITY PROFILES...SEE NO REASON WHY DRY CONDITIONS WILL
NOT CONTINUE THROUGH THE PERIOD. SHOULD SEE WARMING TREND THROUGH
THE PERIOD...ESPECIALLY IN OVERNIGHT LOWS. GENERALLY KEPT WELL ABOVE
NORMAL MAX T FORECAST GOING...ALTHOUGH AM A LITTLE CONCERNED THAT
LATEST GUIDANCE INDICATING WEAK FRONTAL ZONE MOVING THROUGH AREA
RESULTING IN LIGHT...BACKED WINDS THURSDAY.
FRIDAY-MONDAY...
MAIN FOCUS CONTINUES TO BE ON UPPER LOW WHICH IS EXPECTED TO DEVELOP
OVER THE SW US AND POSSIBLY IMPACT OUR CWA FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS HAS BEEN THE CASE THE LAST FEW DAYS THE
GEFS AND ECMWF CONTINUE TO SHOW LARGE SPREAD IN SOLUTIONS RUN TO RUN
FOR THIS SYSTEM...WITH THE OPERATIONAL GFS SLIGHTLY MORE CONSISTENT.
THIS TROUGH IS STILL SOUTH OF THE ALEUTIAN ISLANDS OVER THE NORTHERN
PACIFIC....AND UNTIL IT IS BETTER SAMPLED IT IS HARD FOR ME TO MAKE
LARGE CHANGES TO THIS FORECAST PERIOD. CONFIDENCE IS STILL HIGHEST
ACROSS OUR EASTERN CWA...THOUGH I HAVE EXPANDED CHANCE POPS FURTHER
WEST TO ACCOUNT FOR LATEST ECMWF TRENDS. OTHER COMPLICATING FACTOR
IS WAA ADVERTISED BY ECMWF AND GFS WHICH COULD DELAY SNOW CHANGE
OVER. CONSIDERING THE ABSENCE OF STRONG CAA BEHIND THIS SYSTEM...AND
RELIANCE ON EVAPORATIVE PROCESSES FOR CHANGE OVER I AM NOT CONFIDENT
THAT WE WOULD SEE LARGE SNOW ACCUMULATIONS EVEN WITH THE MOST
FAVORABLE TRACKS. I BUMPED UP THE LOW TEMP FORECAST TO LOW 30S
FRIDAY NIGHT AND THIS STILL MIGHT BE TOO COOL IF WE SEE THICK CLOUD
COVER.
SHORTWAVE RIDGING SHOULD KEEP CONDITIONS DRY SATURDAY AND SUNDAY. BY
MONDAY GFS/ECMWF ARE BOTH INDICATING ANOTHER TROUGH IMPACTING THE
HIGH/CENTRAL PLAINS...THOUGH THERE ARE SIGNIFICANT DIFFERENCES IN
EVOLUTION. I DECIDED TO KEEP SLIGHT CHANCE POPS IN PLACE MONDAY AS A
STARTING POINT...SINCE RAIN OR SNOW CANT BE RULED OUT WITH
ADVERTISED PATTERN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1000 PM MST MON DEC 10 2012
VFR THROUGH THE PERIOD AT KGLD AND KMCK. WINDS WILL BACK TO THE
WEST THEN SOUTHWEST WITH SPEEDS AROUND 10KTS OR SO THROUGH THE
DAY TUESDAY AS A LEE TROUGH DEVELOPS TO THE WEST OF THE AREA.
DURING THE EVENING HOURS SOUTH-SOUTHWEST WINDS WILL INCREASE
SLIGHTLY AT KGLD WITH SPEEDS OF 12-15KTS. CLOUDINESS WILL BE
LIMITED TO MID AND UPPER LEVELS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...99
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
329 AM EST TUE DEC 11 2012
.Short Term (Today through Wednesday)...
Issued at 300 AM EST Tue Dec 11 2012
In the wake of rapidly exiting low pressure over New England, dry
air has returned to the Lower Ohio Valley. High pressure currently
extends across the southern plains towards the Commonwealth.
Eventually, high pressure will become centered right over Kentucky
by mid-day Wednesday.
Mostly clear, cool, benign weather with light winds will develop
later today and continue through Friday. A stubborn deck of low
clouds will remain in place until after daybreak however. These
strato-cu have not been well forecast by recent mesoscale models,
and persist due to our recent wet weather and quite light winds at
the boundary layer. The RUC is one of the few models that accurately
depict our current strato-cu extending well west across southern
Illinois.
Expect that some clearing will develop across west-central Kentucky
and southwestern Indiana a little bit after dawn. However, the RUC
doesn`t really develop clearing east of Interstate 65 until as late
as noon. To be pessimistic, it is possible that our Bluegrass and
eastern counties may not clear until mid-afternoon or so.
Under light west winds, temperatures will stay cool this afternoon,
with highs ranging from the upper 30s to the lower 40s. For tonight,
expect cold frosty clear conditions with lows falling well down into
the mid 20s. Under clear skies and light winds, Wednesday`s highs
will warm a bit into the mid to upper 40s.
.Long Term (Wednesday Night through Monday)...
Issued at 325 AM EST Tue Dec 11 2012
==============================================
Wednesday Night through Friday Night
Model Preference : Multi-Model Consensus
Forecast Confidence: Medium-High
==============================================
Massive polar vortex looks to stay north of Alaska in the Bering Sea
throughout the upcoming forecast period. This feature combined with
anomalously positive height anomalies across the central Pacific
will lead to a very strong Pacific jet flooding the western US coast
while promoting a deep layer trough to develop. This is not
surprising as the PNA has generally been negative of late and looks
to stay that way through the forecast period according to the
multi-model consensus for which this forecast will lean towards.
With developing trough in the west, downstream ridging is expected
from the Plains and into the eastern US through the period. Small
mid-level wave embedded within the mean flow should be south and
east of our area by Wednesday night. Mid-level heights will rise as
the west coast trough develops, and that combined with surface high
pressure will lead to a dry and quiet weather period through Friday
night. With the upper level ridging building in, we should see a
fairly good moderation in temperatures as the work week ends.
Lows Thursday morning will likely drop into the lower-middle 20s
with possibly some upper teens in the typical colder spots.
However, high temperatures should rebound nicely during the day with
highs reaching the upper 40s across southern Indiana and the
northern half of KY with lower 50s across southern KY. Lows
Thursday night probably will not cool off all that much due to the
increased southerly flow expected. Nonetheless, temperatures should
be near seasonal norms with lows in the upper 20s to around 30.
High temperatures on Friday should be a bit warmer with readings
generally in the 50-55 degree range across southern Indiana and
northern Kentucky. Highs in the mid-upper 50s are likely across
southern Kentucky. Lows Friday night should not be as cold as
clouds will be on the increase ahead of the next weather system.
Probably will see some sort of NE to SW gradient across the area by
late Friday and early Saturday with lows in the lower-mid 30s in the
northeast with upper 30s to around 40 in the central and southwest
sections.
==============================================
Saturday through Tuesday
Model Preference : Euro/Euro Ensembles
Forecast Confidence: Low-Medium
==============================================
Forecast through this period looks rather stormy as a pair of
weather systems will likely affect the region through the period.
The first system is likely to affect the region on Saturday as a
mid-level wave ejects out of the southwestern US and heads northeast
across the Plains and into the Great Lakes. This system will
probably result in another snow storm across the northern plains and
into the western Great Lakes as the low pressure system head
northwest of us. Surface warm front will surge through the region
on Saturday placing us in the warm sector for this storm. Plenty of
clouds and showers will likely accompany the front as it passes
through. As the low slowly heads into the Great Lakes, a surface
cold front will swing through the region sometime on Sunday.
Additional showers and possibly some thunderstorms will be possible
ahead and along the front depending on the instability with the
system. Precipitation will likely push off to the east late Sunday
with cooler, yet seasonal air, pushing back into the region.
After a brief quiet period on Monday, eyes will turn to the next
weather system that is poised to kick out of the southwest US during
the day on Monday. The eventual track of this system is a bit in
question due to the models handling of the developing blocking
pattern across Canada late in the period. While both the GFS and
Euro show the NAO trending negative, each model is very different in
its block configuration. Given the recent 7-day verification of the
Euro and its ensembles over the GFS, have trended the forecast more
toward the Euro at this juncture. With that said, a very strong
closed upper low should eject out of the southern Plains and head
east-northeastward through the Ohio Valley. At the surface, a
strong low pressure system will develop in the lower-Mississippi
Valley and then head north-northeast. The track of the storm looks
to be west of the Ohio Valley, yielding yet another possible snow
storm for the Midwest and western Great Lakes. With the Ohio Valley
remaining on the east side of the system, we`re likely to be warm
sectored again with several round of showers and possible
thunderstorms from Monday night through Tuesday.
Highs Saturday will be above seasonal averages with readings in the
upper middle-upper 50s in the north and upper 50s to around 60 in
the south. Lows Saturday night will cool back into the lower-middle
40s, but only rise slightly on Sunday into the mid-upper 40s. Main
cold push looks to be Sunday night and early Monday with
temperatures falling into the lower-mid 30s. Highs on Monday should
warm back into the lower-middle 40s with overnight lows cooling back
into the middle 30s. Highs on Tuesday look to be in the
middle-upper 40s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 0020 AM EST Tue Dec 11 2012
Ceilings will be slow to rise and dissipate over the next 6 to 12
hours due to low level moisture and very light winds at the boundary
models. The NAM guidance is too fast in clearing out this moisture
and feel that the RUC is more accurate. Ceilings will slowly lift
before clearing, but MVFR/VFR borderline ceilings will probably
persist through around 12 to 14z at BWG and SDF, after which skies
should clear pretty readily.
Initially lower ceilings at LEX will slowly rise above 2k feet after
10z, before clearing out as late as 15 to 16z. Once skies clear,
expect clear skies through the rest of today and overnight into
Wednesday.
Winds will stay light through the TAF period, starting from the
northwest around 5kt this morning, then slowly backing to the
southwest at less than 5kt by this evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......JSD
Long Term........MJ
Aviation.........JSD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1223 AM EST TUE DEC 11 2012
...Updated Aviation Discussion...
.Short Term (Tonight through Tuesday night)...
Issued at 300 PM EST Mon Dec 10 2012
Cold front that moved through before daybreak today is exiting to
the south and east, but the upper trough axis is still working its
way across western Kentucky, and should push through our area by
this evening. Until that happens, low clouds and a mix of cold rain,
snow, and even a few sleet pellets will persist. However, air
temperatures remain a few degrees above freezing, and both soil and
pavement temperatures range from mid-40s to mid-50s, so would not
expect any frozen precip to have a real impact. Most likely scenario
is that snow will melt on contact with the ground.
Biggest question in terms of impact is the potential for wet
roadways to freeze late tonight and early Tuesday morning. Min temps
will drop into the upper 20s in most locations, with mid 20s in the
typical cold spots. WNW winds will stay up around 5-8 mph through
the night, which will help to dry a lot of the residual water on
roadways. This potential drying introduces too much uncertainty to
warrant a travelers advisory, but will provide a heads-up to
transportation officials and possibly mention in HWO.
Chilly high pressure will dominate Tuesday and Tuesday night, with
winds becoming light and variable by mid-afternoon. Max temps will
struggle to crack 40 in this air mass, even under full sunshine.
Went on the low end of guidance because the models do tend to
struggle with these shallow cold air masses. Better radiational
cooling conditions on Tuesday night will allow temps to drop into
the 20s again, only with a bigger spread between urban Louisville
and the sheltered valleys. Some of the traditional cold spots could
bottom out around 20.
.Long Term (Wednesday through Monday)...
Issued at 300 PM EST Mon Dec 10 2012
An upper-level trough will swing through the Ohio Valley Wednesday.
While this will be a dry passage, it will act to clear out the
eastern CONUS and allow for ridging to take hold across the
southeast states. This ridging is also in response to a large low
pressure system diving south along the western CONUS through the end
of the work week. This will set the stage for broad southwest flow
aloft and dry conditions through the end of the work week.
Surface high pressure will shift east across the Ohio Valley and
settle in the southeastern CONUS. Surface winds will transition to
southerly and become breezy by perhaps Friday afternoon, but
especially Saturday as a surface low pressure system moves through
Kansas and Missouri. Dry conditions, mostly clear skies, and warming
temperatures are expected through Friday. Temperatures will continue
to warm through Saturday. High temperatures Wednesday will generally
be in the mid 40s, but will warm solidly into the mid and upper 50s
for Saturday.
Clouds will increase late Friday and precip chances will be on the
rise for the weekend as a low pressure system passes by to the
north. Models agree to disagree with this system, but it appears the
low will pass by to the north, just not sure how far to the north.
The GFS keeps the surface low closer to our area, while the ECMWF
takes it across northern Illinois and is now a little slower with
the front. The GFS is slowly trending toward the ECMWF and the NAEFS
mean solution is much closer to the ECMWF. So, will continue to
trend that direction, which falls in line with the previous forecast.
The trailing cold front is projected to sweep through the forecast
area Saturday night into Sunday, with another shot at area-wide rain
showers. As mentioned in the previous forecast, the trailing cold
front is of Pacific origin. This will cool temperatures slightly
Sunday and Monday. Skies should start to clear late Sunday with
temperatures early next week close to mid-December normals.
&&
.Aviation (06Z TAF Issuance)...
Issued at 0020 AM EST Tue Dec 11 2012
Ceilings will be slow to rise and dissipate over the next 6 to 12
hours due to low level moisture and very light winds at the boundary
models. The NAM guidance is too fast in clearing out this moisture
and feel that the RUC is more accurate. Ceilings will slowly lift
before clearing, but MVFR/VFR borderline ceilings will probably
persist through around 12 to 14z at BWG and SDF, after which skies
should clear pretty readily.
Initially lower ceilings at LEX will slowly rise above 2k feet after
10z, before clearing out as late as 15 to 16z. Once skies clear,
expect clear skies through the rest of today and overnight into
Wednesday.
Winds will stay light through the TAF period, starting from the
northwest around 5kt this morning, then slowly backing to the
southwest at less than 5kt by this evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......RS
Long Term........MP
Aviation.........JSD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
349 AM EST TUE DEC 11 2012
.SHORT TERM... TODAY AND TONIGHT
COMPLEXITIES IN THE FORECAST FOR TODAY INCLUDE EVOLUTION OF LAKE
EFFECT SNOW NEAR THE LAKE HURON SHORELINE DURING THE MORNING ALONG
WITH INLAND CLOUD COVERAGE THROUGHOUT THE DAY.
EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR IN EXETER
INDICATE A BAND OF LAKE EFFECT SNOW PERCOLATING OVER THE SOUTH HALF
OF LAKE HURON WITHIN THE INCREASINGLY CONVERGENT LAKE INDUCED
SURFACE TROUGH. MODEL DEPICTIONS OF 850 MB TEMPERATURE SUGGEST
INSTABILITY IS ALREADY MORE THAN ADEQUATE WITH DELTA-T AVERAGING 18C
OVER THE SOUTH HALF OF THE LAKE. THE SOMEWHAT MUTED CONVECTION
DURING THE EARLY MORNING IS LIKELY A RESULT OF MID LEVEL SUBSIDENCE
INDICATED IN WATER VAPOR IMAGERY ON THE HEELS OF THE SHEAR AXIS
DEPARTING TO THE EAST. THIS IS EXPECTED TO CHANGE AS A SMALL BUT
SUFFICIENTLY STRONG SHORT WAVE SLIDES THROUGH LOWER MICHIGAN TOWARD
SUNRISE. THIS FEATURE HELPED SUPPORT A STRONG LAKE EFFECT BAND OVER
SOUTHERN LAKE MICHIGAN DURING THE NIGHT WITH CONVECTION DEEP ENOUGH
FOR SNOW SHOWERS TO REACH NORTHWEST OHIO. AS THE WAVE MOVES TOWARD
LAKE HURON DURING THE REST OF THE MORNING, IT IS EXPECTED TO BOOST
THE CIRCULATION WITHIN THE LAKE TROUGH AND HELP FLARE UP LAKE EFFECT
SNOW THERE AS WELL BEFORE QUICKLY SLIDING EASTWARD BY LATE MORNING.
AS THE WAVE APPROACHES, IT IS EXPECTED TO DRAW THE LAKE TROUGH
TOWARD THE SHORELINE OF THE THUMB FOR A FEW HOURS AROUND SUNRISE
BEFORE THE PASSAGE OF THE LARGE SCALE SURFACE RIDGE BACKS THE LOW
LEVEL FLOW TOWARD THE SOUTHWEST. MODIFIED RAP MODEL SOUNDINGS
INDICATE LAKE INDUCED CAPE APPROACHING 500 J/KG AND EQUILIBRIUM
LEVEL PUSHING 10 KFT BY 12Z, INGREDIENTS FOR HEAVY LAKE EFFECT SNOW
SHOWERS, BUT A LATE START AND SHORT DURATION WILL BE THE LIMITING
FACTORS IN SUPPORT OF A 1 TO 2 INCH FORECAST.
ELSEWHERE AROUND SE MICHIGAN, THE NORTHERLY LOW LEVEL FLOW HAS
BECOME JUST NEUTRAL ENOUGH TO ALLOW FOR SOME BREAKS IN THE STRATUS
DURING THE EARLY MORNING. EXPECT THIS WILL CONTINUE THROUGH LATE
MORNING BUT IN A RANDOM FASHION THAT WILL PROVIDE INTERVALS OF
PARTLY SUNNY CONDITIONS THROUGH CENTRAL PORTIONS OF LOWER MICHIGAN.
THE BACKING LOW LEVEL FLOW WILL THEN DIRECT CLOUDS, AND PERHAPS EVEN
A FEW SNOW SHOWERS, EASTWARD FROM LAKE MICHIGAN AS PART OF A LARGER
AREA OF STRATUS COVERING THE WESTERN GREAT LAKES. THE EXTRA CLOUD
COVER COMBINED WITH LATE DEVELOPING SOUTHWEST SURFACE WIND WILL
CONFINE MAX TEMPS TO THE LOWER AND MID 30S TODAY. THE SOUTHWEST FLOW
WILL CARRY IN DRY AIR FROM THE MID MISSISSIPPI VALLEY BY TONIGHT
WHICH WILL SCOUR OUT THE LOW CLOUDS BUT NOT RESULT IN MUCH WARMING.
THE INCREASED GRADIENT FLOW WILL BATTLE THE TENDENCY FOR SURFACE
WIND DECOUPLING AND RESULTANT RADIATIONAL COOLING FOR LOWS DROPPING
BACK INTO THE LOWER TO MID 20S.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
VERY LITTLE TO DISCUSS IN THE WEDNESDAY TO FRIDAY TIMEFRAME. THE MAIN
TROUGH AXIS WILL BE OVER LOWER MICHIGAN AT THE START OF THE
PERIOD...WHICH WILL GIVE WAY TO A GENERAL RISING OF GEOPOTENTIAL
HEIGHTS THROUGH THE END OF THE WORK WEEK. SPLIT FLOW IS STILL
FORECASTED TO DEVELOP WITH THE POLAR JET AXIS REMAINING NORTH OF
LAKES SUPERIOR/HURON ALONG WITH THE PERSISTENCE OF A VERY NOTEWORTHY
SOUTHERN STREAM AXIS. GUIDANCE CAME IN MARKEDLY WARMER FOR WEDNESDAY
AND BOOSTED TEMPERATURES UPWARDS A COUPLE OF DEGREES. DAYTIME HIGHS
ARE EXPECTED TO REACH/CLIMB ABOVE 40 DEGREES FOR BOTH THURSDAY AND
FRIDAY.
A TON OF UNCERTAINTY EXISTS WITH REGARDS TO HOW THIS WEEKEND WILL
PLAY OUT. THE PERTINENT WEATHER ASPECTS WILL COME DOWN TO THE
DETAILS. UNFORTUNATELY...THE MODEL DATA SUGGESTS THAT IT WILL TAKE
UNTIL FRIDAY MORNING BEFORE THE MAIN TROUGH AXIS OF THE IMPORTANT
SHORTWAVE WILL COME ONSHORE OF SOUTHERN CA/BAJA OF MEXICO. THAT IS A
LONG TIME TO WAIT. LATEST TRENDING FOR THE 11.00Z SUITE WAS THAT THE
ECMWF ARRIVED IN MORE AGREEMENT WITH THE GFS SOLUTION. THE GFS HAS
BEEN ADVERTISING THE FIRST DEVELOPED SYSTEM (ARRIVING OVER THE GREAT
LAKES ON SATURDAY) WILL RUN INTO A EASTERN CANADIAN/GREENLAND
BLOCKING RIDGE. THE MODELS SUGGEST THAT WHAT BEGINS AS RATHER CRISP
BAROCLINIC DYNAMICS TURNS MUSHY IN AS LITTLE AS 12 HOURS. THE HIGHER
CONFIDENCE PORTION OF THIS FORECAST IS THE HIGH AMOUNT OF MOISTURE
IN TOW WITH THE SYSTEM. THE LIKELIHOOD OF WIDESPREAD PRECIPITATION
IS HIGH AND WENT AHEAD AND HIKED POPS INTO THE HIGH LIKELY RANGE FOR
SATURDAY AND SATURDAY NIGHT. THE ECMWF BRINGS THE MAIN UPPER LEVEL
PV ANOMALY NORTH OF THE SOO...WHICH SUGGESTS THAT PRECIPITATION TYPE
WILL BE ON THE WARM END OF THE SPECTRUM. THE GFS REMAINS A LITTLE
FARTHER SOUTH WITH THE PV ANOMALY...OVER LOWER MICHIGAN AND IS JUST
ONE OF MANY POINTS OF CONTENTION AMONGST THE SUITE.
&&
.MARINE...
WEAK HIGH PRESSURE WILL MOVE QUICKLY THROUGH LAKE HURON AND LOWER
MICHIGAN DURING THE AFTERNOON IN A FAVOR OF THE NEXT LOW PRESSURE
SYSTEM MOVING THROUGH NORTHERN ONTARIO. INCREASING SOUTHWEST WIND
WILL REACH GUSTS TO 30 KNOTS TONIGHT OVER THE OPEN WATERS OF CENTRAL
AND NORTHERN LAKE HURON. THE WIND WILL NOT BE QUITE AS STRONG OVER
SAGINAW BAY BUT STRONG ENOUGH TO BUILD WAVES OVER 4 FEET TONIGHT
THROUGH WEDNESDAY REQUIRING A SMALL CRAFT ADVISORY THERE. A LARGER
SYSTEM IS THEN EXPECTED TO TRACK THROUGH NORTHERN ONTARIO AS WELL
DURING WEDNESDAY NIGHT INTO THURSDAY THAT WILL MAINTAIN SOUTHWEST
WIND OVER THE LAKES AND BRING WARMER AIR OVER THE WATER. THE
INCREASED STABILITY BY THIS TIME WILL LIMIT GUST POTENTIAL TO 30
KNOTS OR LESS THROUGH THURSDAY BEFORE THE TRAILING COLD FRONT
SETTLES OVER THE REGION BY FRIDAY. THE FRONT WILL STALL OVER THE
CENTRAL LAKES AS A STRONG LOW PRESSURE SYSTEM TAKES SHAPE OVER THE
PLAINS STATES AND MOVES INTO THE GREAT LAKES DURING THE WEEKEND.
&&
.AVIATION...ISSUED 1207 AM EST TUE DEC 11 2012
//DISCUSSION...
MVFR STRATUS WILL REMAIN IN PLACE OVER THE AREA WITHIN CYCLONICALLY
CURVED NORTHWEST FLOW THROUGH THE CENTRAL GREAT LAKES. THIS REGIME
WILL COME TO AN END MID/LATE MORNING AS SOUTHWEST WINDS DEVELOP
BETWEEN HIGH PRESSURE DEPARTING INTO QUEBEC AND LOW PRESSURE
TRACKING ALONG THE FAR NORTHERN GREAT LAKES/SOUTHERN ONTARIO.
DURING THE 14Z-16Z TIME FRAME...EXPECT STRATUS TO BEGIN BREAKING
UP WITH VFR CONDITIONS EXPECTED IN THE AFTERNOON/TUESDAY EVENING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET PERSISTING THROUGH
14Z-16Z.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM TUESDAY TO 4 PM
WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT
AVIATION.....DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1229 AM EST TUE DEC 11 2012
.SYNOPSIS...
WIDESPREAD LIGHT RAIN WILL MIX WITH AND CHANGE TO LIGHT SNOW
LATER THIS EVENING BEFORE TAPERING OFF OVERNIGHT. A FEW INCHES
ARE POSSIBLE...MAINLY OVER THE HIGHER TERRAIN OF THE NORTHERN
MOUNTAINS. SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN
EXPECTED FROM TUESDAY ONWARD INTO NEXT WEEKEND AS HIGH PRESSURE
DOMINATES REGIONAL WEATHER CONDITIONS. SEASONABLY COLD
TEMPERATURES TUESDAY INTO WEDNESDAY...WILL MODERATE BY LATE WEEK
INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 919 PM EST MONDAY...SFC OBS INDICATE SLK/WNK AND LKP ACRS
THE DACKS HAVE CHANGED TO SNOW WITH TEMPS NEAR FREEZING ATTM.
LLVL CAA CONTS FROM NW TO SE ACRS OUR CWA THIS EVENING WITH
WHITEFACE AT NEAR 85H DOWN TO 23F. LITTLE SNOW ACCUMULATION HAS
BEEN OBSERVED SO FAR VIA WEB CAMS OR SPOTTER REPORTS. IN
ADDITION...DRIER AIR CONTS TO ALSO ADVECT INTO OUR CWA THIS
EVENING ON NW TO NORTH WINDS BEHIND THE SFC BOUNDARIES. THIS HAS
RESULTED IN A DECREASE IN AREAL COVERAGE/INTENSITY OF PRECIP ACRS
NORTHERN NY AS EXPECTED...WITH MOST OF THE SLV DRY ATTM. HAVE
DECREASED POPS ACRS THE SLV THRU THE REST OF TONIGHT BASED ON
RADAR TRENDS. ELSEWHERE...1000 TO 700MB RH CONTS THRU 05Z ACRS
THE DACKS AND UNTIL 09Z FOR MOST OF CENTRAL/NORTHERN VT
MTNS...SUPPORTING SOME LIGHT SNOWFALL. IN ADDITION...SOME BLOCKED
FLW AND ADDITIONAL LAKE CHAMPLAIN MOISTURE INTERACTION WL HELP TO
KEEP SNOW ACTIVITY GOING A BIT LONGER ACRS THE WESTERN
SLOPES/EASTERN CPV EARLY TUESDAY MORNING. STILL THINKING A
DUSTING TO A COUPLE OF INCHES WITH SOME ISOLATED AREAS ALONG THE
WESTERN SLOPE GETTING 3 INCHES OR SO BY MORNING. LITTLE SNOW
ACCUMULATION IS EXPECTED ON THE WESTERN SIDE OF THE CPV AND CT
RIVER VALLEY. WITH A DUSTING TO 2 INCHES POSSIBLE FOR THE MTNS OF
THE NEK BY TUES AM. TEMPS WL BE TRICKY WITH SHARP NW TO SE
THERMAL GRADIENT ASSOCIATED WITH CAA ACRS OUR CWA. THINKING MID
TEEN SLV/SLK TO L/M30S VSF. AS TEMPS SLOWLY DROP BLW FREEZING
AREAS OF PATCHY BLACK ICE WL BE POSSIBLE AND COULD CREATE A FEW
SLICK SPOTS DURING THE MORNING COMMUTE.
OVERALL FCST IN GOOD SHAPE WITH ONLY SOME MINOR ADJUSTMENTS BASED
ON CRNT TRENDS. LATEST SFC ANALYSIS PLACES LOW PRES NORTH OF THE
BORDER WITH ONE COLD FRNT ACRS THE CPV ATTM...AND ANOTHER ONE
APPROACHING THE SLV...WITH MUCH COLDER AIR BEHIND THIS FRNT. THE
FIRST FRNT HAS RESULTED IN AN OVERALL INCREASE IN AREAL
COVERAGE/INTENSITY OF RAIN SHOWERS ACRS THE CPV AND PARTS OF
CENTRAL/NORTHERN VT THIS EVENING...WITH ADDITIONAL SHOWERS ACRS
NORTHERN NY. WL CONT TO MENTION POPS AT 100% THRU 00Z...THEN
START TO TAPER POPS OFF FROM THE SLV EASTWARD. WHITEFACE OBS DOWN
TO 28F...WHICH INDICATES THE COLDER AIR IS MOVING IN ALOFT...BUT
SFC TEMPS STILL REMAIN ABOVE 0C ACRS OUR CWA...WHICH WL MAKE RAIN
TO SNOW AND AMOUNT OF ACCUMULATION DIFFICULT TONIGHT. BASED ON
OBS AND LATEST RAP MODEL...THINKING CHANGE OVER TO SNOW WL OCCUR
AT SLK BTWN 01Z-02Z...MPV/BTV BY 05Z...AND ACRS EASTERN/SOUTHERN
VT AFT 06Z. NEXT QUESTION WL BE AMOUNT OF RH LEFTOVER...WHICH
RAP/NAM SHOW QUICKLY DISSIPATING AS THERMAL PROFILES BECM COLD
ENOUGH FOR SNOW. THINKING THE COMBINATION OF UPSLOPE FLW...SOME
1000 TO 700MB RH...AND FAVORABLE BLOCKING/CONVERGENCE ACRS THE
CPV...WL RESULT IN A PERIOD OF SNOW SHOWERS WITH SOME
ACCUMULATIONS...WHICH CRNT FCST HAS COVERED NICELY. THINKING
DUSTING TO AN INCH BTV/PBG...AROUND 2" FOR ESSEX/JERICHO...AND UP
TO 3" POSSIBLE NEAR UNDERHILL/STOWE/JAY PEAK BY 12Z TUES AND A
DUSTING TO SEVERAL INCHES FOR THE DACKS...AND ONLY LIGHT AMOUNTS
CT RIVER VALLEY AND SLV. WL CONT TO MONITOR CRNT TRENDS FOR
POTENTIAL ADJUSTMENTS...BUT OVERALL FCST IN GOOD SHAPE.
FORECAST REMAINS ON TRACK FOR TONIGHT WITH NEAR TERM CHALLENGES
BEING THE OVERALL COVERAGE OF PCPN...AND THE EXTENT TO WHICH
COOLING NEAR-SFC THERMAL PROFILES OVERNIGHT LEAD TO MINOR
SNOWFALL ACCUMULATIONS. PARENT LOW PRESSURE SYSTEM RESPONSIBLE
FOR THIS AFTERNOON`S RAIN/SHOWERS CURRENTLY PASSING NORTHEAST
THROUGH THE SLV NEAR MONTREAL AND EXPECT THIS TREND TO CONTINUE
TONIGHT. A GENERAL REBLOSSOMING OF RAINFALL IS NOW OCCURRING
ACROSS THE REGION ASSOCIATED WITH WEAK SFC WAVE RIDING NORTHEAST
ALONG LEAD FRONTAL BOUNDARY FROM CENTRAL PA INTO CENTRAL/WRN NY
STATE UP TO THE PARENT LOW. AN ADDITIONAL 0.15 TO 0.25 INCHES OR
SO IS EXPECTED WITH THIS ACTIVITY THROUGH THE 00-02Z TIME FRAME
AS THE FRONT SWINGS THROUGH THE REGION. TEMPERATURES QUITE MILD
THROUGH EARLY EVENING...NOTED BY MANY READINGS IN THE 40S AND
INTO LOWER AND MID 50S IN SOME CASES AS OF 3 PM.
OF ADDITIONAL INTEREST IS THE PRIMARY POLAR FRONT STILL
STATIONARY FURTHER OFF TO THE NORTHWEST BEHIND THE LEADING FRONT.
MUCH COLDER AIR BACK BEHIND THIS SECONDARY BOUNDARY AND AS
AFOREMENTIONED SFC LOW SWINGS AWAY TO THE NORTHEAST...THIS FRONT
WILL SURGE SOUTHEAST AND OVERTAKE THE LEAD FRONT LATER THIS
EVENING. FLOW TRENDS NORTHWEST BEHIND THIS PASSAGE WITH STRONG
CAA SETTING UP AS 925-850 MB THERMAL PROFILES CRASH AFTER
MIDNIGHT. ALL RELIABLE MODELS SHOW AT LEAST SOME CHANGEOVER TO
SNOW DURING A 3-6 HOUR PERIOD FROM ABOUT 02Z-07Z AS THIS OCCURS
AND BACK EDGE OF PCPN EXITS TO THE EAST. LOW FROUDE NUMBER
PROFILES SUPPORT AMPLE LOW LEVEL BLOCKING FAVORING THE WESTERN
SLOPES AS MEAN PBL WINDFLOW TRENDS NORTHWEST. HOWEVER...
PROBLEMATIC ISSUES ON POTENTIAL ACCUMULATIONS EXIST AS
USUAL...AND MAINLY CONCERN A NARROWING COLUMNAR MOISTURE DEPTH
OVER TIME AND HOW QUICKLY THE NEAR-SFC 2M TEMPERATURES CAN COOL
AS EVIDENCED BY 12Z 3-HRLY MOS NUMBERS. AFTER USING SEVERAL
METHODS...MY BEST ESTIMATE IS FOR ONLY VERY LIGHT ACCUMULATIONS
TO OCCUR IN THE LOWER ELEVATIONS...SAY A DUSTING TO PERHAPS AN
INCH...WITH A GENERAL 1-3 INCH ACCUMULATION EXPECTED ABOVE 1 KFT
AND PERHAPS 3-5" NEAR THE SUMMIT LEVEL. TEMPERATURES TO HOLD MILD
THROUGH EARLY...THAN FALL RATHER SHARPLY LATER TONIGHT BOTTOMING
OUT FROM THE UPPER TEENS TO MID 20S NORTH AND WEST...AND UPPER
20S/LOWER 30S SOUTH/SOUTHEAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 317 PM EST MONDAY...REMAINDER OF THE SHORT TERM THEN TRENDS
RELATIVELY QUITE AS CANADIAN HIGH PRESSURE SETTLES ATOP THE
REGION. OTHER THAN SOME LINGERING NRN MTN FLURRIES IN THE
MORNING...EXPECTING A CHILLY DAY ON TAP FOR TOMORROW (TUESDAY) AS
925 MB TEMPERATURES CONTINUE TO FALL INTO THE -8C TO -12C RANGE
BY MID-AFTERNOON UNDER MODEST NORTHWESTERLY GRADIENT. THIS
SUPPORTS HIGHS HOLDING MAINLY STEADY IN THE 20S FOR MOST
LOCALES...THOUGH A FEW LOWER 30S POSSIBLE IN FAVORED DOWNSLOPE
REGIONS OF SOUTHERN VT.
THEREAFTER...CLEAR TO PTLY CLOUDY SKIES CONTINUE TUESDAY NIGHT
INTO WEDNESDAY NIGHT WITH AFOREMENTIONED HIGH SLIDING SLOWLY ATOP
AND EAST OF THE REGION. AFTER A CHILLY NIGHT TUESDAY NIGHT IN THE
SINGLE DIGITS TO TEENS...READINGS TO REBOUND BACK TO NEAR
SEASONAL NORMS BY WEDNESDAY AS MODEST SOUTHWESTERLY RETURN FLOW
DEVELOPS. AS MENTIONED EARLIER...MAINLY DRY WEATHER EXPECTED
DURING THESE PERIODS...THOUGH I HAVE HINTED AT A FEW FLURRIES
ACROSS THE SLV/DACKS TO ACCT FOR ANY WEAK LAKE ENHANCED ACTIVITY
THAT HI-RES MODELS SUGGEST MAY BE DRIFTING AROUND.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 317 PM EST MONDAY...FIRST HALF OF THE EXTENDED PERIOD WILL
CONTINUE TO FEATURE RATHER QUIET WEATHER THANKS TO HIGH PRESSURE
RIDGING. THINGS GET MORE INTERESTING FOR LATER IN THE WEEKEND AND
EARLY NEXT WEEK WHEN IT APPEARS A MORE UNSETTLED PATTERN WILL SET
UP. UNFORTUNATELY, THE SPREAD IN GUIDANCE IS RATHER LARGE BY THIS
POINT, SO ALTHOUGH CONFIDENCE IS MODERATE/HIGH FOR THURSDAY AND
FRIDAY, IT`S LOW/VERY LOW BY SUNDAY & MONDAY. DAILY SPECIFICS
BELOW:
THURSDAY & FRIDAY: LOW/MID LEVEL RIDGE WILL PERSIST, RESULTING IN
A COUPLE OF DRY AND FAIRLY SUNNY DAYS. TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL BOTH DAYS -- LOTS OF 30S THURSDAY AND 30S
AND 40S (LOWER ELEVATIONS) FOR FRIDAY AS 925MB TEMPERATURES CLIMB
TO -2C TO 0C RANGE. STUCK CLOSE TO GUIDANCE FOR HIGH AND LOW
TEMPERATURES.
SATURDAY: 12Z GFS AND EURO RUNS START TO DIVERGE AT THIS POINT.
GFS INDICATES A VERY WEAK UPPER TROF AND ASSOCIATED WEAK SURFACE
LOW WILL ZIP BY TO OUR NORTH, PERHAPS PRODUCING A FEW MOUNTAIN
FLURRIES. EURO IS EVEN WEAKER WITH THE FEATURE. SHOULD END OUT TO
BE ANOTHER DRY DAY OVERALL, BUT A LITTLE COOLER THAN FRIDAY AS
THE MEAN FLOW SHIFTS MORE WEST/NORTHWEST. AGAIN, STAYED CLOSE TO
GUIDANCE FOR TEMPERATURES.
SUNDAY: MODELS FOR SEVERAL RUNS HAVE BEEN SHOWING SOME SORT OF
UPPER TROF DIGGING TO OUR WEST, WHILE SURFACE LOW PRESSURE PUSHES
OUT OF THE GREAT LAKES AND TOWARD THE COAST. ALL RUNS HAVE BEEN
DIFFERENT IN THE DETAILS. EURO HAS BEEN MORE PROGRESSIVE AND
FASTER WITH THIS, AND THE 12Z EURO IS NO DIFFERENT -- WOULD
SUGGEST LOTS OF CLOUDS AND LIGHT PRECIPITATION BREAKING OUT
SUNDAY MORNING. GFS HOLDS BACK A MORE CUT-OFF LOW FARTHER TO THE
SOUTHWEST, KEEPING THE DAY HERE DRY, AND ONLY SKIMMING THE
SOUTHERN HALF OF THE REGION WITH LIGHT PRECIPITATION SUNDAY NIGHT
AS IT SLIDES THE LOW SOUTH OF NEW ENGLAND. GIVEN OVERALL TRACK
RECORD OF EURO AND HPC`S FAVORING THAT MODEL, HAVE PAINTED IN
CHANCE LEVEL POPS FOR SUNDAY. MODEL PROFILES SUGGEST THAT THERE
COULD BE SOME MIXED PRECIPITATION, BUT THIS FAR OUT I KEPT IT TO
A SIMPLE RAIN/SNOW OPTION. TEMPERATURES -- STUCK A BIT CLOSER TO
THE EURO WHICH FEATURES MOST AREAS REACHING THE 35-40F RANGE.
GOOD DEAL OF BUST POTENTIAL HERE.
MONDAY: MODELS ARE ALL OVER THE PLACE, THOUGH ALL FEATURE SOME
SORT OF STRENGTHENING LOW PRESSURE -- WHETHER FAR SOUTHEAST OF
NEW ENGLAND (12Z GFS), EAST OF MAINE (00Z EURO), OR OVER THE MID-
ATLANTIC (12Z EURO). AT THIS POINT, BEST COURSE IS TO HAVE AT
LEAST CHANCE LEVEL POPS PAINTED IN ACROSS THE ENTIRE REGION. THE
12Z EURO TAKEN AT FACE VALUE WOULD SUGGEST A WET/WINDY/WARM
STORM. FOR TEMPERATURES, STARTED WITH THE EURO, BUT TOOK SEVERAL
DEGREES OFF. STILL ENDED UP WITH A LOT OF 40S FOR HIGHS.
I SUSPECT THE FORECASTS FOR THE WEEKEND AND EARLY NEXT WEEK ARE
GOING TO CHANGE QUITE A BIT BETWEEN NOW AND THEN...
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
THROUGH 06Z WEDNESDAY...COLD FRONT CONTINUES TO PUSH EAST ACROSS
THE NORTH COUNTRY...HAS ALREADY CLEARED MSS...SLK AND PBG...WILL
SOON CLEAR BTV. HAVE KEPT SHOWERS IN FOR A COUPLE MORE HOURS AT
RUT AND MPV. SOME MVFR CONDITIONS MAY LINGER WITH SOME LOW CLOUDS
AROUND...BUT CONDITIONS GRADUALLY IMPROVE THROUGH THE PERIOD.
OUTLOOK 06Z WEDNESDAY THROUGH SATURDAY...SURFACE HIGH PRESSURE
WILL PROVIDE THE ENTIRE REGION WITH VFR CONDITIONS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...NASH
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
437 AM EST TUE DEC 11 2012
.SYNOPSIS...
A LARGE HIGH PRESSURE AREA WILL SETTLE OVER THE REGION FOR THE
REST OF THE WEEK. EXPECT DRY WEATHER WITH SEASONABLY COOL
TEMPERATURES AT FIRST...BUT A GRADUAL WARMING WILL OCCUR LATER IN
THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT SNOW OR RAIN SHOWERS OCCURRING OVER PORTIONS OF THE LAUREL
HIGHLANDS AND NORTHWEST MOUNTAINS. CLOUD LAYER NOT ALL THAT
COLD...AND RATHER SHALLOW. THUS...WHERE TEMPS ARE AT OR BELOW
FREEZING...THERE COULD BE A FEW PATCHES OF FREEZING DRIZZLE. BUT
THE AIR WILL ACTUALLY GET COLDER THROUGH THE MORNING. MANY
LOCATIONS WILL HAVE TO WAIT UNTIL LATE MORNING OF EARLY AFTERNOON
TO SEE THE THERMOMETER RISE...AND THEN ONLY SLIGHTLY. THERE COULD
STILL BE A COATING OF SNOW ON THE HIGHER RIDGES AS SCT SHSN KEEP
GOING FOR MUCH OF THE MORNING. WILL CUT OFF ALL POPS AFTER
THAT...AS ANYTHING WILL BE FLURRIES AFTER THAT. 8H TEMPS LEVEL OFF
AND THEN BEGIN TO RISE LATE TODAY AND THE INVERSION LOWERS
SIGNIFICANTLY BY THE END OF THE DAY. THIS SHOULD SPELL THE END OF
THE STRATO CU. BUT WILL LINGER BKN SKY COVER MOST OF THE DAY IN
THE WEST AND INTO THE EARLY EVENING FOR THE NRN MTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE TAKES OVER TONIGHT AND THE RIDGE SETTLES IN FOR THE
LONG HAUL. BEGINNING A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR
WEATHER. HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER
SIDE OF NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE ENTIRE REGION AS OF 09Z.
HOWEVER...A WEAK WAVE OF LOW PRES ALONG FRONT IS PRODUCING
LINGERING SHRA ACROSS SOUTHEAST PA. RADAR TRENDS SUGGEST THE SHRA
WILL MOVE EAST OF MDT/LNS BY ARND 11Z.
NW WINDS WILL CONTINUE TO FORCE RESIDUAL LOW LVL MOISTURE OVR THE
ALLEGHENY MTNS...LIKELY RESULTING IN IFR CIGS AND OCNL -SHSN AT
BFD AND JST THRU ARND DAWN. MDL SOUNDINGS INDICATE SHALLOW CLOUD
HGTS COULD EVEN YIELD A BIT OF -FZDA POSSIBLE AT JST EARLY THIS
AM. LATEST RAP MDL OUTPUT SUPPORTS THE IDEA OF GRADUALLY IMPROVING
CIGS/VSBYS AT BFD AND JST BY ARND 12Z...AS DRIER AIR WORKS IN FROM
THE WEST.
EAST OF THE MTNS...DRYING/DOWNSLOPING NW FLOW SHOULD YIELD MAINLY
VFR CONDS AT IPT/MDT/LNS THIS MORNING. HOWEVER...MDL SOUNDINGS
AND CLIMATOLOGY WOULD SUGGEST AOO AND UNV COULD SEE OCNL MVFR
STRATOCU EARLY THIS AM.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
HIGH PRES DIRECTLY OVR THE REGION TUE NIGHT SHOULD ENSURE VFR
CONDS AND A NEARLY CALM WIND.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
420 AM EST TUE DEC 11 2012
.SYNOPSIS...
A LARGE HIGH PRESSURE AREA WILL SETTLE OVER THE REGION FOR THE
REST OF THE WEEK. EXPECT DRY WEATHER WITH SEASONABLY COOL
TEMPERATURES AT FIRST...BUT A GRADUAL WARMING WILL OCCUR LATER IN
THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT SNOW SHOWERS OCCURRING OVER PORTIONS OF THE LAUREL
HIGHLANDS AND NORTHWEST MOUNTAINS. BUT THE SFC TEMPS STILL TOO
WARM FOR ACCUM IN MOST PLACES...AS THEY ARE JUST GETTING DOWN TO
FREEZING NOW. STILL EXPECT A COATING OF SNOW ON THE HIGHER
RIDGES AS SCT SHSN KEEP GOING INTO MID MORNING. WILL CUT OFF ALL
POPS AFTER THAT...AS ANYTHING WILL BE FLURRIES AFTER THAT. 8H
TEMPS BEGIN TO RISE LATER TODAY AND THIS SHOULD SPELL THE END OF
THE STRATO CU. BUT WILL LINGER BKN SKY COVER INTO THE EARLY
EVENING FOR THE NRN MTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE TAKES OVER TONIGHT AND THE RIDGE SETTLES IN FOR THE
LONG HAUL. BEGINNING A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR
WEATHER. HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER
SIDE OF NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE ENTIRE REGION AS OF 09Z.
HOWEVER...A WEAK WAVE OF LOW PRES ALONG FRONT IS PRODUCING
LINGERING SHRA ACROSS SOUTHEAST PA. RADAR TRENDS SUGGEST THE SHRA
WILL MOVE EAST OF MDT/LNS BY ARND 11Z.
NW WINDS WILL CONTINUE TO FORCE RESIDUAL LOW LVL MOISTURE OVR THE
ALLEGHENY MTNS...LIKELY RESULTING IN IFR CIGS AND OCNL -SHSN AT
BFD AND JST THRU ARND DAWN. MDL SOUNDINGS INDICATE SHALLOW CLOUD HGTS
COULD EVEN YIELD A BIT OF -FZDA POSSIBLE AT JST EARLY THIS AM.
LATEST RAP MDL OUTPUT SUPPORTS THE IDEA OF GRADUALLY IMPROVING
CIGS/VSBYS AT BFD AND JST BY ARND 12Z...AS DRIER AIR WORKS IN FROM
THE WEST.
EAST OF THE MTNS...DRYING/DOWNSLOPING NW FLOW SHOULD YIELD MAINLY
VFR CONDS AT IPT/MDT/LNS THIS MORNING. HOWEVER...MDL SOUNDINGS AND CLIMATOLOGY
WOULD SUGGEST AOO AND UNV COULD SEE OCNL MVFR STRATOCU EARLY THIS
AM.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
HIGH PRES DIRECTLY OVR THE REGION TUE NIGHT SHOULD ENSURE VFR
CONDS AND A NEARLY CALM WIND.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
135 AM EST TUE DEC 11 2012
.SYNOPSIS...
A LARGE HIGH PRESSURE AREA WILL SETTLE OVER THE REGION FOR THE
REST OF THE WEEK. EXPECT DRY WEATHER WITH SEASONABLY COOL
TEMPERATURES AT FIRST...BUT A GRADUAL WARMING WILL OCCUR LATER IN
THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LIGHT SNOW SHOWERS OCCURRING OVER PORTIONS OF THE LAUREL
HIGHLANDS AND NORTHWEST MOUNTAINS. BUT THE SFC TEMPS STILL TOO
WARM FOR ACCUM IN MOST PLACES...AS THEY ARE JUST GETTING DOWN TO
FREEZING NOW. STILL EXPECT A COATING OF SNOW ON THE HIGHER
RIDGES AS SCT SHSN KEEP GOING INTO MID MORNING. WILL CUT OFF ALL
POPS AFTER THAT...AS ANYTHING WILL BE FLURRIES AFTER THAT. 8H
TEMPS BEGIN TO RISE LATER TODAY AND THIS SHOULD SPELL THE END OF
THE STRATO CU. BUT WILL LINGER BKN SKY COVER INTO THE EARLY
EVENING FOR THE NRN MTS.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE TAKES OVER TONIGHT AND THE RIDGE SETTLES IN FOR THE
LONG HAUL. BEGINNING A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR
WEATHER. HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER
SIDE OF NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE ENTIRE REGION AT 06Z. UPPER
LVL TROF LIFTING THRU CENTRAL PA...PRODUCING LAST BATCH OF STEADY
RAIN ACROSS EASTERN PA AT 0530Z. BEHIND THIS FEATURE NW WINDS
WILL CONTINUE TO FORCE RESIDUAL LOW LVL MOISTURE OVR THE ALLEGHENY
MTNS...LIKELY RESULTING IN IFR CIGS AND OCNL -SHSN AT JST THRU
ARND 12Z. LATEST RAP MDL OUTPUT SUPPORTS THIS IDEA OF PERSISTENT
IFR CONDS AT JST THRU DAWN. AT BFD...ARRIVAL OF DRIER AIR AND
LESS SIGNIFICANT OROGRAPHIC FORCING SHOULD YIELD MAINLY MVFR
STRATOCU THIS MORNING.
EAST OF THE MTNS...DRYING/DOWNSLOPING NW FLOW SHOULD YIELD MAINLY
VFR CONDS AFTER 06Z. HOWEVER...CLIMATOLOGY WOULD SUGGEST AOO AND
UNV COULD SEE OCNL MVFR STRATOCU EARLY THIS AM.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
HIGH PRES DIRECTLY OVR THE REGION TUE NIGHT SHOULD ENSURE VFR
CONDS AND A NEARLY CALM WIND.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1241 AM EST TUE DEC 11 2012
.SYNOPSIS...
COLDER AIR WILL SWEEP INTO THE REGION TONIGHT BEHIND A COLD FRONT.
RECENT WET WEATHER WILL GIVE WAY TO COLDER AND DRIER CONDITIONS
FOR TUESDAY AND THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SFC COLD FRONT IN NOW EXITING LANCASTER COUNTY. RAIN SHOWERS HAVE
CHANGED TO SNOW SHOWERS OVER PORTIONS OF THE LAUREL HIGHLANDS...
WEST CENTRAL MOUNTAINS AND NORTHWEST MOUNTAINS. WITH FROPA...TEMPS
IN THE LOWER 50S HAVEN FALLEN BACK THROUGH THE 40S AND INTO THE
MID TO UPPER 30S OVER THE WEST AND NORTH. DESPITE MARGINAL TEMPS...
STILL EXPECT A COATING OF SNOW ON THE HIGHER RIDGES. ELSEWHERE..NO
ACCUMS ARE EXPECTED.
COLDER AIR CONTINUES TO WORK IN OVERNIGHT...TAKING A GOOD PORTION OF
THE OVERNIGHT TO REACH THE LOWER SUSQ. AIR STILL NOT FORMIDABLE
FOR DECEMBER THOUGH...AS THESE READINGS REMAIN WELL ABOVE NORMAL
FOR THIS TIME OF YEAR. HIGH PRESSURE BEGINS TO BUILD IN LATE
TONIGHT INTO TUE AS CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING
FOR MOST...POSS TUE AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
COLD FRONT HAS PUSHED SOUTHEAST OF THE ENTIRE REGION AT 06Z. UPPER
LVL TROF LIFTING THRU CENTRAL PA...PRODUCING LAST BATCH OF STEADY
RAIN ACROSS EASTERN PA AT 0530Z. BEHIND THIS FEATURE NW WINDS
WILL CONTINUE TO FORCE RESIDUAL LOW LVL MOISTURE OVR THE ALLEGHENY
MTNS...LIKELY RESULTING IN IFR CIGS AND OCNL -SHSN AT JST THRU
ARND 12Z. LATEST RAP MDL OUTPUT SUPPORTS THIS IDEA OF PERSISTENT
IFR CONDS AT JST THRU DAWN. AT BFD...ARRIVAL OF DRIER AIR AND
LESS SIGNIFICANT OROGRAPHIC FORCING SHOULD YIELD MAINLY MVFR
STRATOCU THIS MORNING.
EAST OF THE MTNS...DRYING/DOWNSLOPING NW FLOW SHOULD YIELD MAINLY
VFR CONDS AFTER 06Z. HOWEVER...CLIMATOLOGY WOULD SUGGEST AOO AND
UNV COULD SEE OCNL MVFR STRATOCU EARLY THIS AM.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
HIGH PRES DIRECTLY OVR THE REGION TUE NIGHT SHOULD ENSURE VFR
CONDS AND A NEARLY CALM WIND.
OUTLOOK...
WED-FRI...NO SIG WX EXPECTED.
SAT...RAIN/FZRA POSSIBLE LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1045 PM CST MON DEC 10 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
725 PM CST MON DEC 10 2012
725 PM UPDATE...LATEST RADAR IMAGERY...WEB CAM HERE AT OUR OFFICE
AS WELL AS THE 01Z OBSERVATION FROM KOVS ALL SHOWING AN INCREASE
IN SNOW DEVELOPMENT IN THE STRATUS DECK THAT ENCOMPASSES MOST
LOCATIONS ALONG AND EAST OF THE MISSISSIPPI RIVER. BEST GUESS IS
THAT THERE IS SOME INCREASING TURBULENCE IN THE STRATUS DECK AHEAD
OF THE HIGH PRESSURE RIDGE BUILDING INTO THE AREA...AND GIVEN THAT
THE STRATUS DECK LIES IN THE DENDRITIC GROWTH ZONE PER 00Z GRB/DVN
SOUNDINGS...IT DOES NOT TAKE MUCH TO GET SNOW GOING. OVER THE LAST
TWO HOURS...THE MOTION OF THE SNOW ON RADAR IS FOLLOWING AN
EASTWARD PROGRESSION AROUND 11 KT. HAVE USED THIS MOTION IN
SHOWING AN EXTRAPOLATION OF THE CURRENT RADAR IMAGERY FOR THE
PRECIPITATION CHANCE FORECAST THROUGH THE NIGHT. REGARDING THE
CHANCES...GIVING THAT WE ARE DEALING WITH DENDRITES AND THE
FORCING IS WEAK AT BEST...IT IS LIKELY WE MAY NOT SEE MUCH LIQUID
EQUIVALENT QPF OUT OF THIS. HOWEVER...A FEW TENTHS OF AN INCH OF
SNOW COULD ACCUMULATE. SINCE THE PRECIPITATION CHANCE DEFINITION
IS FOR A 0.01 OF LIQUID EQUIVALENT...ONLY HAVE 20 TO 30 PERCENT
CHANCES AT THE MOMENT WITH UP TO A HALF INCH OF SNOWFALL
ACCUMULATION.
PREVIOUS DISCUSSION ISSUED AT 332 PM...
AT 3 PM...LOW CLOUDS PERSISTED ACROSS MUCH OF THE FORECAST AREA.
THIS MOISTURE WAS TRAPPED BELOW A SUBSIDENCE INVERSION. THE
VISIBLE AND FOG PRODUCT /11-3.9 MICRON CHANNEL/ SHOW THAT THE
CLOUDS ARE STARTING TO BREAK UP IN THE DODGE CENTER...AUSTIN...
CHARLES CITY AREAS. THE RAP SEEMS TO BE HANDLING THIS THE BEST.
THEY SHOW THAT A NARROW AREA OF CLEARING WILL MOVE EAST ACROSS
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THIS EVENING. THIS AREA
REMAINS NARROW DUE TO ANOTHER AREA OF CLOUDS MOVING INTO THE
REGION FROM THE DAKOTAS. THIS CLEARING WILL ALLOW A RAPID DROP IN
TEMPERATURES DUE TO FRESH SNOW AND LIGHT WINDS...AND THEN THE
TEMPERATURES WILL RISE AS THE CLOUDS MOVE BACK INTO THE AREA.
ON TUESDAY AFTERNOON AND EVENING...A SHORT WAVE TROUGH WILL MOVE
ACROSS THE AREA. AHEAD OF THIS WAVE...MODERATE 270 TO 280K
ISENTROPIC LEADS TO SATURATION UP TO 775 MB. HOWEVER AS THE WAVE
IS MOVING THROUGH THE REGION...THERE IS VERY LITTLE OMEGA AND THE
LOW LEVEL LAPSE RATES ARE NOT THAT STEEP. AS A RESULT...NOT
EXPECTING ANY ACCUMULATING SNOW. HOWEVER WOULD NOT BE TOO
SURPRISED TO SEE A FEW FLURRIES. SINCE THIS WAVE IS CURRENTLY NOT
PRODUCING ANYTHING UPSTREAM AND THE FORCING AND MOISTURE LOOKS
SIMILAR...DID NOT INCLUDE THEM IN THE FORECAST AT THIS TIME.
ON WEDNESDAY...THE 500 MB FLOW BECOMES ZONAL. THIS KEEPS THE NEXT
2 SHORT WAVE TROUGHS /WEDNESDAY AND THURSDAY/ NEAR THE
U.S./CANADIAN BORDER. BOTH OF THESE SYSTEMS WILL DRAW WARMER AIR
INTO THE REGION. WHILE THE MODELS WERE PUSHING MUCH OF THE AREA
INTO THE 35 TO 45 DEGREE RANGE FOR HIGH TEMPERATURES...LOWERED THEM
A COUPLE OF DEGREES DUE TO THE SNOW PACK.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
332 PM CST MON DEC 10 2012
FROM FRIDAY NIGHT INTO SATURDAY NIGHT...THE MAIN CONCERN WILL BE THE
TRACK OF A SYSTEM MOVING OUT OF THE SOUTHWEST UNITED STATES. AS
THIS SYSTEM MOVES NORTHEAST IT WILL BRING WARM AIR AND GULF
MOISTURE WITH IT. PRECIPITABLE WATER VALUES CLIMB ANYWHERE FROM
150 TO 200 PERCENT OF NORMAL. BOTH THE ECMWF AND GEM HAVE A MUCH
FURTHER NORTH TRACK THAN THE GFS. AS A RESULT...THEY BRING RAIN
INTO SOUTHWEST WISCONSIN AND NORTHEAST IOWA...AND A WINTRY MIX OF
SNOW AND SLEET OR ALL SNOW ACROSS THE REMAINDER OF THE AREA FROM
FRIDAY NIGHT INTO SATURDAY...AND THE PRECIPITATION CHANGES OVER TO
ALL SNOW BEFORE IT ENDS ON SATURDAY NIGHT. MEANWHILE THE GFS IS
ABOUT 6 HOURS SLOWER AND IT ALSO IS FAR ENOUGH SOUTH THAT ONLY THE
AREAS SOUTH OF THE INTERSTATE 90 CORRIDOR WOULD SEE SNOW FROM THIS
SYSTEM. THE GFS ENSEMBLE CONTINUES TO SHOW A WIDESPREAD OF
SOLUTIONS. A FEW OF THEM ARE SIMILAR TO THE ECMWF AND GEM...BUT
THERE ARE ALSO A FEW THAT NO PRECIPITATION AT ALL. OVERALL THE
ECMWF HAS BEEN THE MOST CONSISTENT...SO TRENDED THE FORECAST
TOWARD IT.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1044 PM CST MON DEC 10 2012
A SURFACE RIDGE OF HIGH PRESSURE CROSSING THE TAF SITES HAS
YIELDED VFR CONDITIONS TO BEGIN THE FORECAST. TO THE WEST...A LOW
PRESSURE TROUGH HAS MOVED INTO WESTERN MINNESOTA. EXPECT THIS
TROUGH TO CROSS THE TAF SITES THIS MORNING. ALONG AND AROUND
IT...OBSERVATIONS ARE SHOWING A BAND OF MVFR STRATUS...THUS HAVE
MOVED UP THE TIMING OF THE MVFR CEILINGS TO 12Z AT KRST AND 13Z AT
KLSE. SOME LIGHT SNOW OR FLURRIES COULD OCCUR WITH THIS TROUGH AS
WELL...BUT CONFIDENCE AGAIN REMAINS TOO LOW TO MENTION. IF SNOW
DOES OCCUR...VISIBILITIES COULD BRIEFLY GO MVFR. IN THE WAKE OF
THE TROUGH...MODELS HAVE BEEN SUGGESTING AN EXPANSIVE MVFR STRATUS
TO MOVE IN. HOWEVER...SATELLITE AND SURFACE OBSERVATIONS ACROSS
THE DAKOTAS SHOW MAINLY VFR CONDITIONS. A FEW MVFR STRATOCUMULUS
ARE PRESENT...WHILE AT THE SAME TIME THERE ARE AREAS OF CLEAR
SKIES. GIVEN THE CONDITIONS UPSTREAM IN THE DAKOTAS...HAVE WENT
WITH THE IDEA OF A BROKEN VFR STRATUS DECK FOR THE AFTERNOON AND
EVENING. WITH THE TROUGH PASSAGE...EXPECT WINDS TO SWING AROUND
MORE WESTERLY AND INCREASE TO 10-15 KT. THE WINDS WILL DIMINISH IN
THE EVENING AS THE PRESSURE GRADIENT RELAXES SOME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
332 PM CST MON DEC 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE/AJ
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1041 AM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS MORNING...A FRONTAL BOUNDARY WILL DRIFT SLOWLY EASTWARD AS
THE UPPER FLOW CONTINUES TO BE SOUTHWEST. THEREFORE...THERE SHOULD
NOT BE MUCH TO PUSH THE COLD FRONT. 13 KM RUC DOES SHOW SOME LOW
LEVEL COLD AIR ADVECTION AT 925 MB. MADE MINOR TWEAKS TO TEMPS
USING LATEST MAV GUIDANCE AND RAN MAX TEMP SMART TOOL. NOT MUCH
CHANGE THOUGH. DECIDED TO KEEP INCREASING POPS MAINLY SOUTH AND
EAST PORTIONS AS DEEPER MOISTURE ON IR SATELLITE MOVING TOWARD
THE REGION.
THIS AFTERNOON....THE FRONT WILL BE STALLED NEAR THE COAST. THE
FRONT WILL BE PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL
SHORTWAVE TROUGH OVER THE GULF OF MEXICO SHOULD RESULT IN A
MOISTURE INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS
INCREASE. THERE MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE
POPS WITH THE GREATEST CHANCE IN THE SOUTHEAST PART.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
EXPECT A CONTINUED SERIES OF LOW PRESSURE SYSTEMS MOVING
NORTHEASTWARD ALONG THE STALLED FRONTAL ZONE. THE MODELS GENERALLY
SHOW DEEPER MOISTURE JUST EAST OF THE FORECAST AREA WITH THE
FARTHEST EXTENT WESTWARD WEDNESDAY AND WEDNESDAY NIGHT ASSOCIATED
WITH THE MAIN MID-LEVEL SHORTWAVE TROUGH. THE NAM...GFS...AND
ECMWF APPEAR TO INDICATE ENOUGH MOISTURE IN THE EAST PART FOR
LIKELY POPS WEDNESDAY OR WEDNESDAY NIGHT. THE GUIDANCE CONSENSUS
SUPPORTED POPS OF LIKELY EAST TO CHANCE WEST. THERE WILL BE A
TIGHT MOISTURE GRADIENT FROM WEST TO EAST AND THIS MAKES FORECAST
CONFIDENCE LOW. THE GUIDANCE TEMPERATURES APPEAR TOO WARM
WEDNESDAY BECAUSE OF A WEDGE PATTERN. OTHERWISE...USED THE
CONSENSUS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE AREA ON SATURDAY WILL MOVE OFF THE COAST ON
SUNDAY. THE MODELS SHOW A MOISTURE INCREASE SUNDAY AS A COLD FRONT
MOVES INTO THE AREA FROM THE WEST. WILL INCREASE POPS TO 20-35
PERCENT SATURDAY NIGHT INTO SUNDAY NIGHT TO ACCOUNT FOR POSSIBLE
SHOWER ACTIVITY ASSOCIATED WITH THE FRONT. MODELS DEVELOP A LOW
PRESSURE SYSTEM AHEAD OF A CLOSE UPPER LOW OVER THE SOUTHERN
PLAINS. THIS IS FORECAST IN THE MONDAY/TUESDAY TIME FRAME WITH THE
GFS FASTER THAN THE ECMWF. WILL INCREASE POPS AGAIN ON TUESDAY
INTO THE 30 PERCENT RANGE BUT THERE IS HIGH UNCERTAINTY AT THIS
TIME WITH RESPECT TO THIS FEATURE...ESPECIALLY THE TIMING. EXPECT
TEMPERATURES ABOVE NORMAL THROUGH SUNDAY THEN CLOSER TO NORMAL
MONDAY AND TUESDAY AFTER THE FRONTAL PASSAGE.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
COLD FRONT PUSHING THROUGH THE AREA THIS MORNING WITH DRIER AIR
WORKING IN FROM THE WEST. THIS HAS BROUGHT MAINLY VFR CIGS ABOVE
3 KFT TO THE TAF SITES. HOWEVER...IR SATELLITE SHOWS DEEPER MOISTURE
MOVING NORTHEAST FROM THE GULF AND THIS MAY LOWER CIGS BACK BELOW
3 KFT LATER THIS AFTERNOON OR EARLY THIS EVENING. SINCE TIMING IS
AN ISSUE...DECIDED TO KEEP VFR CONDITIONS DURING THIS TIME PERIOD.
SOUTHWESTERLY FLOW ALOFT WILL KEEP A BLANKET OF MID AND HIGH
CLOUDS OVER THE AREA THROUGH THE FORECAST PERIOD. WINDS WILL BE
FROM THE WEST AROUND 5 TO 8 KNOTS THROUGH THE DAY BEFORE
DIMINISHING AND TURNING MORE NORTHERLY LATE IN THE FORECAST
PERIOD. SOME ISOLATED SHOWERS CANNOT BE RULED OUT BUT EVEN IF RAIN
DOES OCCUR IT SHOULD NOT RESULT IN ANY REDUCTION OF VSBYS/CIGS.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TONIGHT
AND WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
911 AM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIS MORNING...A FRONTAL BOUNDARY WILL DRIFT SLOWLY EASTWARD AS
THE UPPER FLOW CONTINUES TO BE SOUTHWEST. THEREFORE...THERE SHOULD
NOT BE MUCH TO PUSH THE COLD FRONT. 13 KM RUC DOES SHOW SOME LOW
LEVEL COLD AIR ADVECTION AT 925 MB. MADE MINOR TWEAKS TO TEMPS
USING LATEST MAV GUIDANCE AND RAN MAX TEMP SMART TOOL. NOT MUCH
CHANGE THOUGH. DECIDED TO KEEP INCREASING POPS MAINLY SOUTH AND
EAST PORTIONS AS DEEPER MOISTURE ON IR SATELLITE MOVING TOWARD
THE REGION.
THIS AFTERNOON....THE FRONT WILL BE STALLED NEAR THE COAST. THE
FRONT WILL BE PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL
SHORTWAVE TROUGH OVER THE GULF OF MEXICO SHOULD RESULT IN A
MOISTURE INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS
INCREASE. THERE MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE
POPS WITH THE GREATEST CHANCE IN THE SOUTHEAST PART.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
EXPECT A CONTINUED SERIES OF LOW PRESSURE SYSTEMS MOVING
NORTHEASTWARD ALONG THE STALLED FRONTAL ZONE. THE MODELS GENERALLY
SHOW DEEPER MOISTURE JUST EAST OF THE FORECAST AREA WITH THE
FARTHEST EXTENT WESTWARD WEDNESDAY AND WEDNESDAY NIGHT ASSOCIATED
WITH THE MAIN MID-LEVEL SHORTWAVE TROUGH. THE NAM...GFS...AND
ECMWF APPEAR TO INDICATE ENOUGH MOISTURE IN THE EAST PART FOR
LIKELY POPS WEDNESDAY OR WEDNESDAY NIGHT. THE GUIDANCE CONSENSUS
SUPPORTED POPS OF LIKELY EAST TO CHANCE WEST. THERE WILL BE A
TIGHT MOISTURE GRADIENT FROM WEST TO EAST AND THIS MAKES FORECAST
CONFIDENCE LOW. THE GUIDANCE TEMPERATURES APPEAR TOO WARM
WEDNESDAY BECAUSE OF A WEDGE PATTERN. OTHERWISE...USED THE
CONSENSUS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE LATEST GFS AND ECMWF AGREE SHOWING DRY RIDGING BECOMING
DOMINATE THURSDAY AND CONTINUING OVER THE AREA FRIDAY. THE MODELS
SHOW A MOISTURE INCREASE SATURDAY WITH A FRONT IN THE AREA SUNDAY.
THE GFS ENSEMBLE MEANS SUPPORT LOW POPS AT THIS TIME. EXPECT
TEMPERATURES ABOVE NORMAL PRIOR TO FRONTAL PASSAGE.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
COLD FRONT PUSHING THROUGH THE AREA THIS MORNING WITH DRIER AIR
WORKING IN FROM THE WEST. THIS HAS BROUGHT MAINLY VFR CIGS ABOVE
3 KFT TO THE TAF SITES. HOWEVER...IR SATELLITE SHOWS DEEPER MOISTURE
MOVING NORTHEAST FROM THE GULF AND THIS MAY LOWER CIGS BACK BELOW
3 KFT LATER THIS AFTERNOON OR EARLY THIS EVENING. SINCE TIMING IS
AN ISSUE...DECIDED TO KEEP VFR CONDITIONS DURING THIS TIME PERIOD.
SOUTHWESTERLY FLOW ALOFT WILL KEEP A BLANKET OF MID AND HIGH
CLOUDS OVER THE AREA THROUGH THE FORECAST PERIOD. WINDS WILL BE
FROM THE WEST AROUND 5 TO 8 KNOTS THROUGH THE DAY BEFORE
DIMINISHING AND TURNING MORE NORTHERLY LATE IN THE FORECAST
PERIOD. SOME ISOLATED SHOWERS CANNOT BE RULED OUT BUT EVEN IF RAIN
DOES OCCUR IT SHOULD NOT RESULT IN ANY REDUCTION OF VSBYS/CIGS.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TONIGHT
AND WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
635 AM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FRONT WILL BE STALLED NEAR THE COAST TODAY. THE FRONT WILL BE
PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL SHORTWAVE TROUGH
OVER THE GULF OF MEXICO EARLY THIS MORNING SHOULD RESULT IN A
MOISTURE INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS
INCREASE. THERE MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE
POPS WITH THE GREATEST CHANCE IN THE SOUTHEAST PART. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
EXPECT A CONTINUED SERIES OF LOW PRESSURE SYSTEMS MOVING
NORTHEASTWARD ALONG THE STALLED FRONTAL ZONE. THE MODELS GENERALLY
SHOW DEEPER MOISTURE JUST EAST OF THE FORECAST AREA WITH THE
FARTHEST EXTENT WESTWARD WEDNESDAY AND WEDNESDAY NIGHT ASSOCIATED
WITH THE MAIN MID-LEVEL SHORTWAVE TROUGH. THE NAM...GFS...AND
ECMWF APPEAR TO INDICATE ENOUGH MOISTURE IN THE EAST PART FOR
LIKELY POPS WEDNESDAY OR WEDNESDAY NIGHT. THE GUIDANCE CONSENSUS
SUPPORTED POPS OF LIKELY EAST TO CHANCE WEST. THERE WILL BE A
TIGHT MOISTURE GRADIENT FROM WEST TO EAST AND THIS MAKES FORECAST
CONFIDENCE LOW. THE GUIDANCE TEMPERATURES APPEAR TOO WARM
WEDNESDAY BECAUSE OF A WEDGE PATTERN. OTHERWISE...USED THE
CONSENSUS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE LATEST GFS AND ECMWF AGREE SHOWING DRY RIDGING BECOMING
DOMINATE THURSDAY AND CONTINUING OVER THE AREA FRIDAY. THE MODELS
SHOW A MOISTURE INCREASE SATURDAY WITH A FRONT IN THE AREA SUNDAY.
THE GFS ENSEMBLE MEANS SUPPORT LOW POPS AT THIS TIME. EXPECT
TEMPERATURES ABOVE NORMAL PRIOR TO FRONTAL PASSAGE.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
COLD FRONT PUSHING THROUGH THE AREA THIS MORNING WITH LINGERING MVFR
AND LOW VFR CIGS. EXPECT MVFR CIGS ABOVE 2000 FT 12Z-15Z THEN CIGS
LIFT TO VFR AS DRIER AIR WORKS INTO THE REGION. SOUTHWESTERLY FLOW
ALOFT WILL KEEP A BLANKET OF MID AND HIGH CLOUDS OVER THE AREA
THROUGH THE FORECAST PERIOD. WINDS WILL BE FROM THE WEST AROUND 5
TO 8 KNOTS THROUGH THE DAY BEFORE DIMINISHING AND TURNING MORE
NORTHERLY LATE IN THE FORECAST PERIOD. SOME ISOLATED SHOWERS
CANNOT BE RULED OUT BUT EVEN IF RAIN DOES OCCUR IT SHOULD NOT
RESULT IN ANY REDUCTION OF VSBYS/CIGS.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TONIGHT
AND WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
552 AM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
THE FRONT WILL BE STALLED NEAR THE COAST TODAY. THE FRONT WILL BE
PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL SHORTWAVE TROUGH
OVER THE GULF OF MEXICO EARLY THIS MORNING SHOULD RESULT IN A
MOISTURE INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS
INCREASE. THERE MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE
POPS WITH THE GREATEST CHANCE IN THE SOUTHEAST PART. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
EXPECT A CONTINUED SERIES OF LOW PRESSURE SYSTEMS MOVING
NORTHEASTWARD ALONG THE STALLED FRONTAL ZONE. THE MODELS GENERALLY
SHOW DEEPER MOISTURE JUST EAST OF THE FORECAST AREA WITH THE
FARTHEST EXTENT WESTWARD WEDNESDAY AND WEDNESDAY NIGHT ASSOCIATED
WITH THE MAIN MID-LEVEL SHORTWAVE TROUGH. THE NAM...GFS...AND
ECMWF APPEAR TO INDICATE ENOUGH MOISTURE IN THE EAST PART FOR
LIKELY POPS WEDNESDAY OR WEDNESDAY NIGHT. THE GUIDANCE CONSENSUS
SUPPORTED POPS OF LIKELY EAST TO CHANCE WEST. THERE WILL BE A
TIGHT MOISTURE GRADIENT FROM WEST TO EAST AND THIS MAKES FORECAST
CONFIDENCE LOW. THE GUIDANCE TEMPERATURES APPEAR TOO WARM
WEDNESDAY BECAUSE OF A WEDGE PATTERN. OTHERWISE...USED THE
CONSENSUS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE LATEST GFS AND ECMWF AGREE SHOWING DRY RIDGING BECOMING
DOMINATE THURSDAY AND CONTINUING OVER THE AREA FRIDAY. THE MODELS
SHOW A MOISTURE INCREASE SATURDAY WITH A FRONT IN THE AREA SUNDAY.
THE GFS ENSEMBLE MEANS SUPPORT LOW POPS AT THIS TIME. EXPECT
TEMPERATURES ABOVE NORMAL PRIOR TO FRONTAL PASSAGE.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
COLD FRONT REMAINS JUST WEST OF THE TERMINALS BUT WILL PUSH EAST
DURING THE 06Z-12Z TIME FRAME. VFR CONDITIONS TO START THE
FORECAST BUT EXPECT MVFR CIGS TO ACCOMPANY THE FRONTAL ZONE AS IT
MOVES EAST ACROSS THE AREA. MVFR CIGS EXPECTED 09Z-15Z WITH
POSSIBLE IFR CIGS AGS/DNL. LIGHT WEST TO SOUTHWEST WINDS THROUGH
15Z THEN PICKING UP FROM THE WEST AROUND 5 TO 8 KNOTS. COLD FRONT
TO STALL EAST OF THE AREA TODAY AND EXPECT MID AND HIGH CLOUDS TO
CONTINUE TO PROVIDE A VFR CLOUD DECK THROUGH THE END OF THE
FORECAST PERIOD.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TUESDAY
NIGHT THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
439 AM MST TUE DEC 11 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
04Z WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED BROAD TROUGHING
ACROSS MUCH OF THE CONUS. PV ANALYSIS INDICATED SHORT WAVE TROUGH
MOVING INTO NORTHERN COLORADO...WITH AREA OF LIGHT SNOW OCCURRING TO
THE SOUTHWEST OF MAIN ANOMALY. AT THE SFC...HIGH PRESSURE WAS
CENTERED ACROSS THE AREA WITH AREA OF VERY LOW DEWPOINTS NOTED
ACROSS SOUTHWEST KANSAS...WITH HIGHER DEWPOINTS MOVING INTO THE AREA
FROM THE NORTH. 00Z RAOBS UPSTREAM OF THE AREA INDICATED MUCH
HIGHER LAPSE RATES THAN 24 HOURS AGO...AND WHILE LAPSE RATES WERE
NOT DRY ADIABATIC THEY WOULD SUPPORT CONDITIONAL INSTABILITY OR
NEUTRAL CONDITIONS SHOULD SATURATION OCCUR.
MAIN FORECAST CONCERNS WILL BE LIGHT SNOW POTENTIAL THROUGH THE
EARLY MORNING HOURS FOLLOWED BUY RISING TEMPS AND FIRE WX POTENTIAL
THROUGH THURSDAY.
TODAY...INITIAL CONCERN WILL BE AREA OF LIGHT SNOW TO THE WEST OF THE
AREA OCCURRING AHEAD OF WEAK PV ANOMALY. RUC SEEMS TO BE ONLY NEAR
TERM MODEL THAT HAS CAUGHT ON TO THIS...ALTHOUGH PRECIP AREA LOOKS
TOO LARGE FOR WHAT IS OCCURRING. FROM WHAT I CAN TELL FROM THE POINT
SOUNDINGS...FORCED ASCENT REALLY CONCENTRATED IN THE LOW LEVELS
AROUND THE DGZ WHICH IS LOCATED AROUND H7. GIVEN THE OVERALL PATTERN
THINK PRECIP THREAT WILL CONTINUE UNTIL H8-H7 FLOW BECOMES MORE
NORTHWESTERLY LEADING TO WEAK CAA AFTER 09Z. THERE IS SOME
INSTABILITY TO WORK WITH...BUT BASED ON LATEST RADAR TRENDS SEEMS
DOUBTFUL THAT SIG SNOW AMOUNTS WOULD OCCUR IN CWA. OTHERWISE...THINK
PRECIP CHANCES WILL END QUICKLY WITH SKIES CLEARING THROUGH THE DAY
AS LARGE SCALE SUBSIDENCE MOVES OVER THE AREA BEHIND TROUGH.
TONIGHT-TOMORROW...SHORT WAVE RIDGE WILL AMPLIFY OVER THE AREA
DURING THE PERIOD BRINGING DRY CONDITIONS AND A FEW HIGH CLOUDS.
OVERALL DO NOT THINK CLOUDS WILL HAVE A BIG IMPACT ON
TEMPS...ALTHOUGH AM A LITTLE CONCERNED THAT STRONG H3 FLOW
PERPENDICULAR TO ROCKIES MAY CREATE AN ENHANCED AREA OF CIRRUS DURING
THE AFTERNOON. DESPITE THE LOW LEVEL WESTERLY FLOW...THE POTENTIAL
FOR HIGH CLOUD COVER AND LATEST ROUND OF OPERATIONAL DATA HAS
TEMPERED MY CONFIDENCE IN A SIG WARM UP SOMEWHAT AND HAVE LOWERED
HIGHS A FEW DEGREES ACROSS EASTERN CWA. FOR THE AREAS THAT DO MIX
OUT/WARM STRONGLY UPPER 50S AND AFTERNOON HUMIDITIES AROUND 15
PERCENT LIKELY. WILL HAVE NEAR CRITICAL FIRE WX CONDITIONS IN THIS
AREA...BUT NOT A LOT OF SUPPORT FOR STRONG WINDS EVEN WITH
DEVELOPING LEE TROUGH. CANNOT RULE OUT RED FLAG CONDITIONS
DEVELOPING...BUT CONFIDENCE TOO LOW IN WINDS MATERIALIZING TO ISSUE
WATCH ATTM.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
WED NIGHT-THUR NIGHT...SHORT WAVE RIDGE WILL BE PRIMARY INFLUENCE OF
WEATHER ACROSS THE CWA AS FLOW ALOFT BECOMES MORE AMPLIFIED IN
RESPONSE TO WEST COAST TROUGH. GIVEN THE PATTERN AND VERTICAL
MOISTURE/STABILITY PROFILES...SEE NO REASON WHY DRY CONDITIONS WILL
NOT CONTINUE THROUGH THE PERIOD. SHOULD SEE WARMING TREND THROUGH
THE PERIOD...ESPECIALLY IN OVERNIGHT LOWS. GENERALLY KEPT WELL ABOVE
NORMAL MAX T FORECAST GOING...ALTHOUGH AM A LITTLE CONCERNED THAT
LATEST GUIDANCE INDICATING WEAK FRONTAL ZONE MOVING THROUGH AREA
RESULTING IN LIGHT...BACKED WINDS THURSDAY.
FRIDAY-MONDAY...
MAIN FOCUS CONTINUES TO BE ON UPPER LOW WHICH IS EXPECTED TO DEVELOP
OVER THE SW US AND POSSIBLY IMPACT OUR CWA FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS HAS BEEN THE CASE THE LAST FEW DAYS THE
GEFS AND ECMWF CONTINUE TO SHOW LARGE SPREAD IN SOLUTIONS RUN TO RUN
FOR THIS SYSTEM...WITH THE OPERATIONAL GFS SLIGHTLY MORE CONSISTENT.
THIS TROUGH IS STILL SOUTH OF THE ALEUTIAN ISLANDS OVER THE NORTHERN
PACIFIC....AND UNTIL IT IS BETTER SAMPLED IT IS HARD FOR ME TO MAKE
LARGE CHANGES TO THIS FORECAST PERIOD. CONFIDENCE IS STILL HIGHEST
ACROSS OUR EASTERN CWA...THOUGH I HAVE EXPANDED CHANCE POPS FURTHER
WEST TO ACCOUNT FOR LATEST ECMWF TRENDS. OTHER COMPLICATING FACTOR
IS WAA ADVERTISED BY ECMWF AND GFS WHICH COULD DELAY SNOW CHANGE
OVER. CONSIDERING THE ABSENCE OF STRONG CAA BEHIND THIS SYSTEM...AND
RELIANCE ON EVAPORATIVE PROCESSES FOR CHANGE OVER I AM NOT CONFIDENT
THAT WE WOULD SEE LARGE SNOW ACCUMULATIONS EVEN WITH THE MOST
FAVORABLE TRACKS. I BUMPED UP THE LOW TEMP FORECAST TO LOW 30S
FRIDAY NIGHT AND THIS STILL MIGHT BE TOO COOL IF WE SEE THICK CLOUD
COVER.
SHORTWAVE RIDGING SHOULD KEEP CONDITIONS DRY SATURDAY AND SUNDAY. BY
MONDAY GFS/ECMWF ARE BOTH INDICATING ANOTHER TROUGH IMPACTING THE
HIGH/CENTRAL PLAINS...THOUGH THERE ARE SIGNIFICANT DIFFERENCES IN
EVOLUTION. I DECIDED TO KEEP SLIGHT CHANCE POPS IN PLACE MONDAY AS A
STARTING POINT...SINCE RAIN OR SNOW CANT BE RULED OUT WITH
ADVERTISED PATTERN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 435 AM MST TUE DEC 11 2012
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIODS WITH WESTERLY
WINDS INCREASING TO AROUND 13 KTS THIS AFTERNOON BEFORE DECREASING
AROUND SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS JACKSON KY
906 AM EST TUE DEC 11 2012
.UPDATE...
ISSUED AT 905 AM EST TUE DEC 11 2012
NO EVIDENCE THE CLOUDS ARE GOING TO CLEAR OUT ANYTIME IN THE NEXT 6
TO 12 HOURS AS THE LOW CLOUDS EXTEND WELL BACK TO OUR NORTHWEST. THE
DRIZZLE HAS DIMINISHED WITH THE LACK OF RETURNS ON LOCAL RADAR. THE
12Z RUC HAS A GOOD DEAL OF LOW LEVEL MOISTURE IN PLACE THROUGH 00Z
THIS EVENING. WHILE OTHER OPERATIONAL MODELS SHOW NO SUGGESTION OF
THE CLOUDS CONTINUING...OPTING TO KEEP THEM LONGER THAN PREVIOUSLY
ADVERTISED. IN FACT...GOING TO CARRY A GOOD DEAL OF CLOUD COVER
THROUGH TONIGHT. THIS MAY IMPACT LOWS...BUT DECIDED TO FOCUS ON CLOUD
COVER WITH THIS UPDATE. THERE IS STILL SOME UNCERTAINTY IF/WHEN
CLOUDS MAY CLEAR TONIGHT. IF WE CAN CLEAR OUT LATE...LOWS MAY STILL
BE REALIZED. HOWEVER...CLOUDS WOULD OBVIOUSLY KEEP THINGS A BIT
MILDER. FORECAST UPDATE WILL BE OUT SHORTLY.
UPDATE ISSUED AT 650 AM EST TUE DEC 11 2012
CLOUDS ARE HOLDING ON FAR TO THE WEST EARLY THIS MORNING. WITH SUCH
AN EXPANSE UPSTREAM AND WEAK COLD AIR ADVECTION AND UPSLOPE FLOW TO
PERSIST TODAY...HAVE EXTENDED MOSTLY CLOUDY SKIES THROUGH MORE OF THE
DAY TODAY. WEAK RETURNS ON RADAR HAVE BECOME LIGHTER AND SHIFTED
SOUTHEAST...AND PREVIOUS UPDATE FOR TIMING THE END OF
DRIZZLE/FREEZING DRIZZLE THIS MORNING LOOKS ON TRACK.
UPDATE ISSUED AT 501 AM EST TUE DEC 11 2012
DRIZZLE AND FREEZING DRIZZLE WERE OCCURRING OVER PORTIONS OF THE
SOUTHEAST PART OF THE FORECAST AREA EARLY THIS MORNING...AND HAVE
ADDED IT TO THE FORECAST. AS MOISTURE BECOMES MORE SHALLOW...THIS
SHOULD END LATER THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 222 AM EST TUE DEC 11 2012
AFTER A PROLONGED PERIOD OF PRECIP...LOW LEVEL MOISTURE LINGERS
IN COLD AIR ADVECTION AND UPSLOPE FLOW BEHIND A COLD FRONT. THE NAM
USED TO BE FAIRLY REASONABLE IN HANDLING COLD UPSLOPE FLOW IN COLD
SEASONS IN YEARS PAST. HOWEVER...IT SEEMS TO BE BEHAVING DIFFERENTLY
THIS AUTUMN. IT IS HANDLING THE LOW LEVEL MOISTURE VERY POORLY
EARLY THIS MORNING WHEN COMPARED TO REALITY ON SATELLITE
IMAGERY...SIMILAR TO AN EARLIER MOIST UPSLOPE FLOW EVENT THIS AUTUMN.
THE GFS LOOKS MORE REASONABLE IN ITS FORECAST...BUT STILL MAY BE A
BIT TOO FAST TO DRY THINGS OUT. WILL TENTATIVELY LOOK FOR CLOUDS TO
BREAK UP THIS AFTERNOON AS SURFACE RIDGING BUILDS IN...BUT
CONFIDENCE IN TIMING IS NOT HIGH. WITH THAT IN MIND...PREFER THE
COOLER HIGH TEMPS SHOWN IN THE GFS MOS FOR TODAY.
ONLY HIGH AND MAINLY THIN CLOUDS ARE EXPECTED OVERNIGHT TONIGHT. WITH
LIGHT WINDS AND A DRY SURFACE AIR MASS HAVING ARRIVED...WILL LOOK
FOR A MODEST RIDGE/VALLEY TEMPERATURE DIFFERENCE FOR LOWS. THE CLOUDS
AND WEAK COLD AIR ADVECTION SHOULD PRECLUDE A LARGER DIFFERENCE.
SURFACE RIDGING WILL REMAIN IN PLACE FOR WEDNESDAY...WITH SUNSHINE
AND SLIGHT WARMER TEMPERATURES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 222 AM EST TUE DEC 11 2012
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY NIGHT WITH AN
EXITING TROUGH OFF THE EAST COAST. AFTERWORDS...THE UPPER LEVEL
PATTERN BECOMES ZONAL THROUGH THE REST OF THE WORK WEEK. AT THE
SURFACE...STRONG HIGH PRESSURE WILL STAY POSITIONED OVER APPALACHIA
THROUGH THE WEEK AND INTO SATURDAY. BY FRIDAY...AN TROUGH MOVES
ASHORE THE SOUTHWEST COAST AND INTO THE FOUR CORNERS REGION. MODELS
AGREE ON THE WAVE EJECTING INTO THE CENTRAL PLAINS AND EVENTUALLY
INTO THE MS VALLEY BY 12Z TO 18Z SATURDAY. THE TIMING OF THE GFS AND
EURO ON THE ARRIVAL DO DIVERGE A BIT. ONSET OF PRECIP LOOKS TO BE
LATE SATURDAY. AS WELL...THE 00Z SOLUTION OF THE EURO WOULD SUPPORT
THIS MINDSET AS WELL. WILL ADJUST FOR A SLIGHTLY LATER ARRIVAL FROM
THE SOLUTION PROVIDED FROM THE ALL BLEND MODEL. MODEL SOUNDINGS
WOULD SUGGEST THE POSSIBILITY OF THUNDER WITH THE FRONT INTO SUNDAY.
WILL GO WITH SHOWERS FOR NOW AND WAIT TO SEE IF MODELS HAVE A BETTER
HANDLE ON STABILITY.
CONCERNING TEMPERATURES...A ZONAL PATTERN AND LACK OF ANY
SIGNIFICANT CHANGE IN AIR MASS WILL DURING MUCH OF THE EXTENDED WILL
KEEP TEMPS NEAR IF NOT SLIGHTLY ABOVE NORMAL FOR THE FORECAST AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 650 AM EST TUE DEC 11 2012
MVFR CEILINGS PREVAILED AT THE START OF THE PERIOD...WITH LOCALIZED
IFR. THIS SHOULD PERSIST INTO THIS AFTERNOON...WITH CEILINGS THEN
BREAKING UP. VFR IS FORECAST TO RETURN FROM NORTHWEST TO SOUTHEAST
BETWEEN ABOUT 19Z AND 00Z...BUT CONFIDENCE IN THIS TIMING IS
TENTATIVE/LOW CONFIDENCE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...HAL
LONG TERM....SHALLENBERGER
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
626 AM EST TUE DEC 11 2012
...Updated Aviation Discussion...
.Short Term (Today through Wednesday)...
Issued at 300 AM EST Tue Dec 11 2012
In the wake of rapidly exiting low pressure over New England, dry
air has returned to the Lower Ohio Valley. High pressure currently
extends across the southern plains towards the Commonwealth.
Eventually, high pressure will become centered right over Kentucky
by mid-day Wednesday.
Mostly clear, cool, benign weather with light winds will develop
later today and continue through Friday. A stubborn deck of low
clouds will remain in place until after daybreak however. These
strato-cu have not been well forecast by recent mesoscale models,
and persist due to our recent wet weather and quite light winds at
the boundary layer. The RUC is one of the few models that accurately
depict our current strato-cu extending well west across southern
Illinois.
Expect that some clearing will develop across west-central Kentucky
and southwestern Indiana a little bit after dawn. However, the RUC
doesn`t really develop clearing east of Interstate 65 until as late
as noon. To be pessimistic, it is possible that our Bluegrass and
eastern counties may not clear until mid-afternoon or so.
Under light west winds, temperatures will stay cool this afternoon,
with highs ranging from the upper 30s to the lower 40s. For tonight,
expect cold frosty clear conditions with lows falling well down into
the mid 20s. Under clear skies and light winds, Wednesday`s highs
will warm a bit into the mid to upper 40s.
.Long Term (Wednesday Night through Monday)...
Issued at 325 AM EST Tue Dec 11 2012
==============================================
Wednesday Night through Friday Night
Model Preference : Multi-Model Consensus
Forecast Confidence: Medium-High
==============================================
Massive polar vortex looks to stay north of Alaska in the Bering Sea
throughout the upcoming forecast period. This feature combined with
anomalously positive height anomalies across the central Pacific
will lead to a very strong Pacific jet flooding the western US coast
while promoting a deep layer trough to develop. This is not
surprising as the PNA has generally been negative of late and looks
to stay that way through the forecast period according to the
multi-model consensus for which this forecast will lean towards.
With developing trough in the west, downstream ridging is expected
from the Plains and into the eastern US through the period. Small
mid-level wave embedded within the mean flow should be south and
east of our area by Wednesday night. Mid-level heights will rise as
the west coast trough develops, and that combined with surface high
pressure will lead to a dry and quiet weather period through Friday
night. With the upper level ridging building in, we should see a
fairly good moderation in temperatures as the work week ends.
Lows Thursday morning will likely drop into the lower-middle 20s
with possibly some upper teens in the typical colder spots.
However, high temperatures should rebound nicely during the day with
highs reaching the upper 40s across southern Indiana and the
northern half of KY with lower 50s across southern KY. Lows
Thursday night probably will not cool off all that much due to the
increased southerly flow expected. Nonetheless, temperatures should
be near seasonal norms with lows in the upper 20s to around 30.
High temperatures on Friday should be a bit warmer with readings
generally in the 50-55 degree range across southern Indiana and
northern Kentucky. Highs in the mid-upper 50s are likely across
southern Kentucky. Lows Friday night should not be as cold as
clouds will be on the increase ahead of the next weather system.
Probably will see some sort of NE to SW gradient across the area by
late Friday and early Saturday with lows in the lower-mid 30s in the
northeast with upper 30s to around 40 in the central and southwest
sections.
==============================================
Saturday through Tuesday
Model Preference : Euro/Euro Ensembles
Forecast Confidence: Low-Medium
==============================================
Forecast through this period looks rather stormy as a pair of
weather systems will likely affect the region through the period.
The first system is likely to affect the region on Saturday as a
mid-level wave ejects out of the southwestern US and heads northeast
across the Plains and into the Great Lakes. This system will
probably result in another snow storm across the northern plains and
into the western Great Lakes as the low pressure system head
northwest of us. Surface warm front will surge through the region
on Saturday placing us in the warm sector for this storm. Plenty of
clouds and showers will likely accompany the front as it passes
through. As the low slowly heads into the Great Lakes, a surface
cold front will swing through the region sometime on Sunday.
Additional showers and possibly some thunderstorms will be possible
ahead and along the front depending on the instability with the
system. Precipitation will likely push off to the east late Sunday
with cooler, yet seasonal air, pushing back into the region.
After a brief quiet period on Monday, eyes will turn to the next
weather system that is poised to kick out of the southwest US during
the day on Monday. The eventual track of this system is a bit in
question due to the models handling of the developing blocking
pattern across Canada late in the period. While both the GFS and
Euro show the NAO trending negative, each model is very different in
its block configuration. Given the recent 7-day verification of the
Euro and its ensembles over the GFS, have trended the forecast more
toward the Euro at this juncture. With that said, a very strong
closed upper low should eject out of the southern Plains and head
east-northeastward through the Ohio Valley. At the surface, a
strong low pressure system will develop in the lower-Mississippi
Valley and then head north-northeast. The track of the storm looks
to be west of the Ohio Valley, yielding yet another possible snow
storm for the Midwest and western Great Lakes. With the Ohio Valley
remaining on the east side of the system, we`re likely to be warm
sectored again with several round of showers and possible
thunderstorms from Monday night through Tuesday.
Highs Saturday will be above seasonal averages with readings in the
upper middle-upper 50s in the north and upper 50s to around 60 in
the south. Lows Saturday night will cool back into the lower-middle
40s, but only rise slightly on Sunday into the mid-upper 40s. Main
cold push looks to be Sunday night and early Monday with
temperatures falling into the lower-mid 30s. Highs on Monday should
warm back into the lower-middle 40s with overnight lows cooling back
into the middle 30s. Highs on Tuesday look to be in the
middle-upper 40s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 0020 AM EST Tue Dec 11 2012
Ceilings will be slow to rise and dissipate over the next 6 to 12
hours due to low level moisture and very light winds at the boundary
models. The NAM guidance is too fast in clearing out this moisture
and feel that the RUC is more accurate. Ceilings will slowly lift
before clearing, but MVFR/VFR borderline ceilings will probably
persist through around 12 to 14z at BWG and SDF, after which skies
should clear pretty readily.
Initially lower ceilings at LEX will slowly rise above 2k feet after
10z, before clearing out as late as 15 to 16z. Once skies clear,
expect clear skies through the rest of today and overnight into
Wednesday.
Winds will stay light through the TAF period, starting from the
northwest around 5kt this morning, then slowly backing to the
southwest at less than 5kt by this evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......JSD
Long Term........MJ
Aviation.........JSD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
714 AM EST TUE DEC 11 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST TUE DEC 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE CNTRL CONUS. WEAK SHORTWAVE TROUGHS
FROM CNTRL UPPER MI INTO ERN WI AND OVER MN SUPPORTED AREAS OF VERY
LIGHT SNOW AND FLURRIES. ALTHOUGH RADARS SHOWED DECENT COVERAGE WITH
WEAK RETURNS...OBS INDICATED UPSTREAM VISIBILITIES WERE GENERALLY
AOA 6SM. AT THE SFC...SRLY WINDS WERE INCREASING OVER THE REGION
AHEAD OF TROUGH THAT EXTENDED FROM NW ONTARIO INTO MN.
WITH LIGHT WINDS OVER LAKE MICHIGAN AND LAND BREEZES BECOMING MORE
PROMINENT...MID LAKE LES HAD DEVELOPED OFFSHORE FROM NW LOWER MI.
MAIN FCST CONCERNS ARE LAKE EFFECT SNOW TRENDS/AMOUNTS OFF OF LAKE
MICHIGAN TODAY AND INTO THE KEWEENAW TONIGHT.
TODAY...AS THE MOISTURE AND LIGHT PCPN ASSOCIATED WITH THE SHRTWVS
ADVANCE TO THE EAST AND CONVERGENT SRLY FLOW INCREASES ACROSS LAKE
MICHIGAN...MDLS SUGGEST THAT A DOMINANT LES BAND IS LIKELY TO
DEVELOP. THE HIGH RES MODELS CONSENSUS ALSO INDICATE THAT THE BAND WOULD
LIKELY MOVE ONSHORE EAST OF ISQ AND SPREAD QUICKLY TO THE NORTH AND
EAST INTO LUCE COUNTY BY MID MORNING. ALTHOUGH CONFIDENCE IS HIGH
THAT A BAND WILL MOVE INTO EASTERN UPPER MICHIGAN...THERE IS STILL
UNCERTAINTY WITH THE DETAILS OF TIMING/LOCATION OF THE BAND. WITH A
LONG FETCH ACROSS THE LAKE...AND MODERATE INSTABILITY (850 MB TEMP
OF -11C AND LAKE SFC NEAR 6C)...MODERATE TO STRONG CONV...AND
INVERSION HEIGHTS TO AROUND 10K FT...SNOWFALL INTENSITY SHOULD
BECOME HEAVY AT TIMES. EVEN IF 1-2 INCH PER HOUR SNOWFALL RATES
DEVELOP...THE STEADY EASTWARD PROGRESSION SHOULD LIMIT LCL MAX SNOW
AMOUNTS TO AROUND 4 INCHES. SO...AN LES ADVY WAS POSTED FOR SRN
SCHOOLCRAFT AND LUCE COUNTIES.
OTHERWISE...THE BEST CHANCE FOR ADDITIONAL FLURRIES OR LIGHT SNOW
SHOWERS THIS AFTERNOON WILL BE OVER THE WRN CWA AS YET ANOTHER WEAK
SHRTWV MOVES FROM WRN MN MOVES TOWARD THE AREA.
TONIGHT...THE NW ONTARIO TROUGH WILL MOVE TO THE EAST DRAGGING A
COLD FRONT INTO WRN LAKE SUPERIOR. THE COLDER AIR ALONG WITH WINDS
VEERING WRLY WILL PROVIDE FAVORABLE CONDITIONS FOR LES INTO THE
KEWEENAW. WITH 850 MB TEMPS DROPPING TO AROUND -14C...INVERSION
HEIGHTS AROUND 7K FT...AND LOW LEVEL CONVERGENCE STRENGTHENING
DOWNWIND FROM THE APOSTLE ISLANDS...A MODERATE TO HEAVY LES BAND IS
EXPECTED TO DEVELOP. SNOWFALL AMOUNTS OF AT LEAST 2 TO 4 INCHES ARE
LIKELY...ESPECIALLY IN THE HIGHER TERRAIN FROM TWIN LAKES TO CALUMET.
SINCE THERE STILL IS UNCERTAINTY WITH THE DURATION AND LOCATION OF
THE MAIN LES BAND(S)...NO HEADLINE WAS ISSUED AT THIS TIME.
SUBSIDENCE WITH QUICKLY LOWERING INVERSION HEIGHTS AND DIMINISHING
LES INTENSITY IS EXPECTED AFTER MIDNIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM EST TUE DEC 11 2012
AS STRONG H3 JET REFOCUSES OVER EASTERN SEABOARD BY THURSDAY...
EXPECT AMPLIFIED TROUGHING CURRENTLY IN PLACE OVER MUCH OF CONUS
TO TRANSITION TO SPLIT ZONAL FLOW. NORTHERN PLAINS AND UPPER GREAT
LAKES WILL BE AFFECTED BY NORTHERN STREAM THROUGH REST OF THE WORK
WEEK. DISTURBANCES IN THE NORTHERN STREAM NOT FORECAST TO BE ALL
THAT STRONG AND SINCE MAJORITY THE ENERGY FROM STRONGER SHORTWAVES
STAYS MORE OVER CANADA...EXPECT ONLY MINOR IMPACT TO SENSIBLE WX OVR
LAKE SUPERIOR AND UPR MICHIGAN.
A BIT OF LK EFFECT SNOW TO CONTEND WITH OVER THE KEWEENAW TO OPEN
THE LONG TERM PERIOD ON WEDNESDAY MORNING. KEPT 20 POPS IN THROUGH
MID MORNING...BUT THE SUBSIDENCE/DRYING AOA 850MB/LOWERING INVERSION
AND QUICKLY BACKING BLYR FLOW WILL END ANY WHATEVER LK EFFECT
LINGERS PAST 12Z IN SHORT ORDER. ATTN THEN TURNS TO LEAD WAVE
ZIPPING ALONG US/CANADIAN BORDER LATER WEDNESDAY IN INCREASINGLY
ZONAL FLOW. LARGER SCALE DYNAMICS WITH THE WAVE /H7-H5 Q-VECTOR
CONVERGENCE AND LEFT EXIT REGION JET FORCING/ STAYS MOSTLY OVER
ONTARIO WEDNESDAY AFTN AND WEDNESDAY NIGHT. ONLY MODELS THAT GRAZE
NORTHERN CWA /KEWEENAW AND LUCE COUNTY/ WITH QPF ARE THE 00Z
CANADIAN GEM-NH AND UKMET. OTHER MODELS ARE QUITE DRY BLO THE CLOUD
BASE AROUND H7...SO IT TAKES UNTIL PARCELS REACH OVER NORTHERN LK
SUPERIOR/NORTHERN ONTARIO TO SATURATE/PRECIPITATE. DID NOT WANT TO
COMPLETELY IGNORE GEM-NH AND UKMET...BUT KEPT POPS IN THE FAR NORTH
NO MORE THAN 20 PCT. BEGINNING TO THINK THAT INSTEAD OF PRECIP THAT
GUSTY SW WINDS AND STEADY TEMPS IN THE UPR 20S TO MID 30S MAY BE
MAIN PRIMARY RESULT FROM THIS INITIAL WAVE. H925-H85 WINDS 35-45 KTS
ALONG WITH NEUTRAL TO SLIGHLY UNSTABLE TEMPERATURE PROFILE SFC-H9
ALONG WITH PRESSURE FALLS OVR LK SUPERIOR AND INTO ONTARIO MAY
RESULT IN AREAS NEAR LK SUPERIOR OVR NCNTRL UPR MICHIGAN...NEAR LK
MICHIGAN AND OVER MUCH OF EASTERN CWA GUSTING SEEING WINDS GUSTING
20-35 MPH THROUGH THE NIGHT WITH MINIMAL TEMP FALL. WENT WITH
NON-DIURNAL TEMP TREND TO COVER THIS POSSIBILITY.
LEAD WAVE HEADS TOWARD QUEBEC BY DAYBREAK THURSDAY AS SFC TROUGH
EASES ACROSS LK SUPERIOR/NORTHERN UPR MICHIGAN. ANOTHER WAVE IS
LURKING UPSTREAM IN THE QUICK ZONAL FLOW ALOFT. UKMET/GEM-NH
STRONGEST WITH WAVE...GFS/ECMWF NOT SO MUCH. SINCE THE LOW-LEVEL
TROUGH BECOMES PARALLEL WITH UPPER FLOW...NOT TOO KEEN ON PUSHING
TROUGH AS FAR SOUTH AS GEM-NH HAS IT BY THURSDAY AFTN. INSTEAD KEPT
BOUNDARY HUNG UP OVR KEWEENAW WITH JUST A SMALL CHANCE OF SNOW
SHOWERS BY AFTN AS SHALLOW COLD AIR TRIES TO SETTLE BACK ACROSS
NORTHERN CWA. TEMPS AHEAD OF FRONT...WHEREVER IT ENDS UP...COULD
GET FAIRLY WARM WITH READINGS WELL INTO THE 30S...ESPECIALLY EAST.
FOR THURSDAY NIGHT INTO FRIDAY...MAY BE SETTING UP FOR ANOTHER
DZ/FZDZ OR SNOW SCENARIO. GFS IS COLDER...BUT GFS/ECMWF/GEM-NHEM
INDICATE H85 TEMPS BORDERLINE TO GET ICE NUCLEATION/SNOW. ALSO GFS
AND ECMWF INDICATE A LOT OF LOW-LEVEL MOISTURE BUT NOT AS MUCH H85
MOISTURE. INTRODUCED SOME DZ/FZDZ FOR FRIDAY AND FRIDAY NIGHT
BETWEEN THE TROUGH THAT DROPS THROUGH LATE THURSDAY AND OUT AHEAD
OF STRONGER LOW PRESSURE SYSTEM MOVING INTO REGION NEXT WEEKEND.
UPSLOPE NE THEN SE WINDS WOULD ONLY HELP OUT THE DZ/FZDZ.
AS FLOW BECOMES SPLIT LATE THIS WEEK...STRONG SOUTHERN STREAM WAVE
TAKES SHAPE OVER DESERT SOUTHWEST. IT IS THIS WAVE THAT BECOMES MAIN
INSTIGATOR FOR LEE ROCKIES CYCLOGENESIS LATE FRIDAY INTO SATURDAY.
THIS SOUTHERN STREAM WAVE/ASSOCIATED SFC LOW ARE FORECAST TO EJECT
OUT OF SOUTHERN PLAINS INTO WESTERN GREAT LAKES OR OHIO VALLEY TO
END THE WEEKEND. FLOW PATTERN BECOMES QUITE MESSY THOUGH AS ANOTHER
WAVE WILL BE QUICKLY FOLLOWING INTO SOUTHERN PLAINS AND THERE IS
EVEN A WAVE IN THE NORTHERN STREAM THAT WILL TRY TO MAKE A RUN INTO
THE NORTHERN PLAINS...THOUGH IT DOES SEEM AT LEAST AT THIS POINT...
THAT THAT WAVE MAY GET DEFLECTED OFF INTO CANADA AWAY FROM THE FRAY.
ALL THE WAVES PROBABLY WILL END UP INTERACTING WITH EACH OTHER IN
SOME FORM OR ANOTHER. NET RESULT IS A NOT SO CLEAR CUT FORECAST OF
THE SFC LOW/THERMAL PROFILE/PRECIPITATION COVERAGE AND INTENSITY
ACROSS UPPER LAKES REGION LATER SATURDAY INTO SUNDAY. ONLY REAL
MODEL TREND OF NOTE IS GFS HAS TRENDED TOWARD ECMWF IDEA OF A MORE
CLOSED OFF SOUTHERN STREAM/SFC LOW SINCE THE 18Z RUN ON MONDAY AFTN.
TROUBLE IS THAT THIS WAVE IS STILL OVER GULF OF ALASKA THIS MORNING
AND REALLY WILL NOT BE ONSHORE OVER CONUS FOR BETTER ROAB SAMPLING
UNTIL LIKELY FRIDAY MORNING AT THE EARLIEST. EXPECT UNCERTAINTY TO
CLOUD THE FORECAST UNTIL THAT POINT WITH THE SPECIFICS OF THE TRACK
OF SFC LOW. A CONSENSUS WAS RETAINED FOR POPS NOW. FOR OVERALL PTYPE
LEANED ON LARGE SCALE THICKNESSES...THOUGH WHERE FLOW WAS ONSHORE
OFF THE GREAT LAKES...KEPT SOME MENTION OF RAIN AS WELL WITH TEMPS
EXPECTED TO BE IN THE MID 30S. LINGERED CHANCE POPS FOR MAINLY SNOW
OVER THE EAST ON SUNDAY. NOT A LOT OF COLD AIR FCST TO BE AROUND IN
WAKE OF THE MAINLY SOUTHERN STREAM ORIGIN SYSTEM...SO KEPT POPS FOR
ANY LK EFFECT INTO MONDAY ON THE LOW SIDE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 714 AM EST TUE DEC 11 2012
EXPECT CIGS AT OR SLIGHTLY ABOVE MVFR MOST OF THE DAY WITH
INCREASING SW FLOW AHEAD OF A AN APPROACHING TROUGH. MORE
PERSISTENT MVFR CONDITIONS MIGHT IMPACT CMX/IWD IN THE AFTN AS
THIS TROF CLOSES IN...LIMITED LLVL MSTR RETURN WL LIKELY LEAD TO A
PERSISTENCE OF MAINLY VFR WX. FOLLOWING THE TROF PASSAGE AND WIND
SHIFT TO THE W IN THE EARLY EVNG...EXPECT SHSN TO IMPACT THE EXPOSED
KEWEENAW PENINSULA...WITH IFR OR LIFT CONDITIONS LIKELY AT CMX.
DOWNSLOPE NATURE OF W WIND BEHIND THIS TROF PASSAGE WL LIKELY RESULT
IN VFR CIGS AT SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST TUE DEC 11 2012
WINDS 25 KTS OR BLO THROUGH MIDDAY WEDNESDAY THEN EXPECT INCREASING
SOUTH TO SOUTHWEST WINDS LATE WEDNESDAY/WEDNESDAY NIGHT AND INTO
EARLY THURSDAY MORNING. GALES LIKELY OVER EASTERN PORTIONS OF LAKE
SUPERIOR SO HAVE ISSUED GALE WATCH. TROUGH DROPS ACROSS THE LAKE BY
THURSDAY EVENING. WINDS WILL DIMINISH SIGNIFICANTLY THURSDAY NIGHT
INTO FRIDAY IN WAKE OF THIS TROUGH. LOW PRESSURE SYSTEM DEVELOPING
IN THE PLAINS PUSHES INTO WESTERN GREAT LAKES LATE SATURDAY INTO
SUNDAY WHILE HIGH PRESSURE MOVES ACROSS NEW ENGLAND. WINDS SHOULD
INCREASE FROM THE EAST ON SATURDAY OVER LAKE SUPERIOR. EXACT TRACK
AND DEPTH OF SFC LOW REMAINS UNCERTAIN THOUGH...SO DID NOT GO STRONG
ON WINDS AT THIS TIME. POSSIBLE THAT WINDS MAY EVENTUALLY NEED TO BE
INCREASED COMPARED TO WHAT IS IN THE CURRENT FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ014.
LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MIZ007.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY EVENING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ265>267.
LAKE MICHIGAN...
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LMZ248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
700 AM EST TUE DEC 11 2012
.AVIATION...
//DISCUSSION...
A POCKET OF DRY AIR HELPED SCOUR OUT STRATUS OVER THE TERMINAL SITES
DURING THE EARLY MORNING. THIS PROMISES VFR SCATTERED CLOUD
CONDITIONS THROUGH MID MORNING BEFORE CLOUDS MOVE BACK IN AS THE LOW
LEVEL FLOW BACKS TOWARD THE SOUTHWEST. EVEN THEN, VFR IS EXPECTED TO
PERSIST WITH SOME QUESTION WHETHER MVFR TO OUR SOUTH AND WEST WILL
BE ABLE TO SURVIVE THE TRIP THROUGH THE INCREASED SOUTHWEST FLOW.
DRY AIR OVER THE MID MISSISSIPPI VALLEY WILL THEN SCOUR ANY
REMAINING CLOUDS FROM THE AREA BY TONIGHT. THE EXCEPTION MAY BE AT
MBS WHERE SOUTHWEST FLOW WILL REMAIN COLD ENOUGH TO GENERATE
STRATOCU FROM LAKE MICHIGAN WHICH COULD SUSTAIN A MVFR/LOW VFR
CEILING THROUGH THE NIGHT. THESE CLOUDS COULD EVENTUALLY FILL IN
OVER POINTS SOUTH AS THE LOW LEVEL WINDS TURN MORE TOWARD THE WEST
BY SUNRISE WEDNESDAY.
FOR DTW... THE RETURN OF CLOUDS DURING THE MORNING WILL BE IN THE
VFR RANGE WITH CEILING ABOVE 5000 FEET INITIALLY, BUT ARE EXPECTED
TO LOWER TO VFR BELOW 5000 FEET BY LATE MORNING. CONFIDENCE IS HIGH
THAT DRY AIR OVER ILLINOIS WILL MOVE IN TONIGHT AND SCOUR ANY
REMAINING LOWER CLOUDS OUT OF THE AREA. MOSTLY CLEAR CONDITIONS WILL
THEN LAST UNTIL CLOSE TO SUNRISE WEDNESDAY WHEN PATCHES OF VFR
STRATOCU BELOW 5000 FEET WILL AGAIN BE POSSIBLE FROM LAKE MICHIGAN.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE IN TIMING AND COVERAGE OF CEILING BELOW 5000
TODAY AND LATE TONIGHT.
&&
.PREV DISCUSSION...ISSUED 349 AM EST TUE DEC 11 2012
SHORT TERM... TODAY AND TONIGHT
COMPLEXITIES IN THE FORECAST FOR TODAY INCLUDE EVOLUTION OF LAKE
EFFECT SNOW NEAR THE LAKE HURON SHORELINE DURING THE MORNING ALONG
WITH INLAND CLOUD COVERAGE THROUGHOUT THE DAY.
EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR IN EXETER
INDICATE A BAND OF LAKE EFFECT SNOW PERCOLATING OVER THE SOUTH HALF
OF LAKE HURON WITHIN THE INCREASINGLY CONVERGENT LAKE INDUCED
SURFACE TROUGH. MODEL DEPICTIONS OF 850 MB TEMPERATURE SUGGEST
INSTABILITY IS ALREADY MORE THAN ADEQUATE WITH DELTA-T AVERAGING 18C
OVER THE SOUTH HALF OF THE LAKE. THE SOMEWHAT MUTED CONVECTION
DURING THE EARLY MORNING IS LIKELY A RESULT OF MID LEVEL SUBSIDENCE
INDICATED IN WATER VAPOR IMAGERY ON THE HEELS OF THE SHEAR AXIS
DEPARTING TO THE EAST. THIS IS EXPECTED TO CHANGE AS A SMALL BUT
SUFFICIENTLY STRONG SHORT WAVE SLIDES THROUGH LOWER MICHIGAN TOWARD
SUNRISE. THIS FEATURE HELPED SUPPORT A STRONG LAKE EFFECT BAND OVER
SOUTHERN LAKE MICHIGAN DURING THE NIGHT WITH CONVECTION DEEP ENOUGH
FOR SNOW SHOWERS TO REACH NORTHWEST OHIO. AS THE WAVE MOVES TOWARD
LAKE HURON DURING THE REST OF THE MORNING, IT IS EXPECTED TO BOOST
THE CIRCULATION WITHIN THE LAKE TROUGH AND HELP FLARE UP LAKE EFFECT
SNOW THERE AS WELL BEFORE QUICKLY SLIDING EASTWARD BY LATE MORNING.
AS THE WAVE APPROACHES, IT IS EXPECTED TO DRAW THE LAKE TROUGH
TOWARD THE SHORELINE OF THE THUMB FOR A FEW HOURS AROUND SUNRISE
BEFORE THE PASSAGE OF THE LARGE SCALE SURFACE RIDGE BACKS THE LOW
LEVEL FLOW TOWARD THE SOUTHWEST. MODIFIED RAP MODEL SOUNDINGS
INDICATE LAKE INDUCED CAPE APPROACHING 500 J/KG AND EQUILIBRIUM
LEVEL PUSHING 10 KFT BY 12Z, INGREDIENTS FOR HEAVY LAKE EFFECT SNOW
SHOWERS, BUT A LATE START AND SHORT DURATION WILL BE THE LIMITING
FACTORS IN SUPPORT OF A 1 TO 2 INCH FORECAST.
ELSEWHERE AROUND SE MICHIGAN, THE NORTHERLY LOW LEVEL FLOW HAS
BECOME JUST NEUTRAL ENOUGH TO ALLOW FOR SOME BREAKS IN THE STRATUS
DURING THE EARLY MORNING. EXPECT THIS WILL CONTINUE THROUGH LATE
MORNING BUT IN A RANDOM FASHION THAT WILL PROVIDE INTERVALS OF
PARTLY SUNNY CONDITIONS THROUGH CENTRAL PORTIONS OF LOWER MICHIGAN.
THE BACKING LOW LEVEL FLOW WILL THEN DIRECT CLOUDS, AND PERHAPS EVEN
A FEW SNOW SHOWERS, EASTWARD FROM LAKE MICHIGAN AS PART OF A LARGER
AREA OF STRATUS COVERING THE WESTERN GREAT LAKES. THE EXTRA CLOUD
COVER COMBINED WITH LATE DEVELOPING SOUTHWEST SURFACE WIND WILL
CONFINE MAX TEMPS TO THE LOWER AND MID 30S TODAY. THE SOUTHWEST FLOW
WILL CARRY IN DRY AIR FROM THE MID MISSISSIPPI VALLEY BY TONIGHT
WHICH WILL SCOUR OUT THE LOW CLOUDS BUT NOT RESULT IN MUCH WARMING.
THE INCREASED GRADIENT FLOW WILL BATTLE THE TENDENCY FOR SURFACE
WIND DECOUPLING AND RESULTANT RADIATIONAL COOLING FOR LOWS DROPPING
BACK INTO THE LOWER TO MID 20S.
LONG TERM...WEDNESDAY THROUGH MONDAY
VERY LITTLE TO DISCUSS IN THE WEDNESDAY TO FRIDAY TIMEFRAME. THE MAIN
TROUGH AXIS WILL BE OVER LOWER MICHIGAN AT THE START OF THE
PERIOD...WHICH WILL GIVE WAY TO A GENERAL RISING OF GEOPOTENTIAL
HEIGHTS THROUGH THE END OF THE WORK WEEK. SPLIT FLOW IS STILL
FORECASTED TO DEVELOP WITH THE POLAR JET AXIS REMAINING NORTH OF
LAKES SUPERIOR/HURON ALONG WITH THE PERSISTENCE OF A VERY NOTEWORTHY
SOUTHERN STREAM AXIS. GUIDANCE CAME IN MARKEDLY WARMER FOR WEDNESDAY
AND BOOSTED TEMPERATURES UPWARDS A COUPLE OF DEGREES. DAYTIME HIGHS
ARE EXPECTED TO REACH/CLIMB ABOVE 40 DEGREES FOR BOTH THURSDAY AND
FRIDAY.
A TON OF UNCERTAINTY EXISTS WITH REGARDS TO HOW THIS WEEKEND WILL
PLAY OUT. THE PERTINENT WEATHER ASPECTS WILL COME DOWN TO THE
DETAILS. UNFORTUNATELY...THE MODEL DATA SUGGESTS THAT IT WILL TAKE
UNTIL FRIDAY MORNING BEFORE THE MAIN TROUGH AXIS OF THE IMPORTANT
SHORTWAVE WILL COME ONSHORE OF SOUTHERN CA/BAJA OF MEXICO. THAT IS A
LONG TIME TO WAIT. LATEST TRENDING FOR THE 11.00Z SUITE WAS THAT THE
ECMWF ARRIVED IN MORE AGREEMENT WITH THE GFS SOLUTION. THE GFS HAS
BEEN ADVERTISING THE FIRST DEVELOPED SYSTEM (ARRIVING OVER THE GREAT
LAKES ON SATURDAY) WILL RUN INTO A EASTERN CANADIAN/GREENLAND
BLOCKING RIDGE. THE MODELS SUGGEST THAT WHAT BEGINS AS RATHER CRISP
BAROCLINIC DYNAMICS TURNS MUSHY IN AS LITTLE AS 12 HOURS. THE HIGHER
CONFIDENCE PORTION OF THIS FORECAST IS THE HIGH AMOUNT OF MOISTURE
IN TOW WITH THE SYSTEM. THE LIKELIHOOD OF WIDESPREAD PRECIPITATION
IS HIGH AND WENT AHEAD AND HIKED POPS INTO THE HIGH LIKELY RANGE FOR
SATURDAY AND SATURDAY NIGHT. THE ECMWF BRINGS THE MAIN UPPER LEVEL
PV ANOMALY NORTH OF THE SOO...WHICH SUGGESTS THAT PRECIPITATION TYPE
WILL BE ON THE WARM END OF THE SPECTRUM. THE GFS REMAINS A LITTLE
FARTHER SOUTH WITH THE PV ANOMALY...OVER LOWER MICHIGAN AND IS JUST
ONE OF MANY POINTS OF CONTENTION AMONGST THE SUITE.
MARINE...
WEAK HIGH PRESSURE WILL MOVE QUICKLY THROUGH LAKE HURON AND LOWER
MICHIGAN DURING THE AFTERNOON IN A FAVOR OF THE NEXT LOW PRESSURE
SYSTEM MOVING THROUGH NORTHERN ONTARIO. INCREASING SOUTHWEST WIND
WILL REACH GUSTS TO 30 KNOTS TONIGHT OVER THE OPEN WATERS OF CENTRAL
AND NORTHERN LAKE HURON. THE WIND WILL NOT BE QUITE AS STRONG OVER
SAGINAW BAY BUT STRONG ENOUGH TO BUILD WAVES OVER 4 FEET TONIGHT
THROUGH WEDNESDAY REQUIRING A SMALL CRAFT ADVISORY THERE. A LARGER
SYSTEM IS THEN EXPECTED TO TRACK THROUGH NORTHERN ONTARIO AS WELL
DURING WEDNESDAY NIGHT INTO THURSDAY THAT WILL MAINTAIN SOUTHWEST
WIND OVER THE LAKES AND BRING WARMER AIR OVER THE WATER. THE
INCREASED STABILITY BY THIS TIME WILL LIMIT GUST POTENTIAL TO 30
KNOTS OR LESS THROUGH THURSDAY BEFORE THE TRAILING COLD FRONT
SETTLES OVER THE REGION BY FRIDAY. THE FRONT WILL STALL OVER THE
CENTRAL LAKES AS A STRONG LOW PRESSURE SYSTEM TAKES SHAPE OVER THE
PLAINS STATES AND MOVES INTO THE GREAT LAKES DURING THE WEEKEND.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM TUESDAY TO 4 PM
WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....BT
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
546 AM EST TUE DEC 11 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST TUE DEC 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE CNTRL CONUS. WEAK SHORTWAVE TROUGHS
FROM CNTRL UPPER MI INTO ERN WI AND OVER MN SUPPORTED AREAS OF VERY
LIGHT SNOW AND FLURRIES. ALTHOUGH RADARS SHOWED DECENT COVERAGE WITH
WEAK RETURNS...OBS INDICATED UPSTREAM VISIBILITIES WERE GENERALLY
AOA 6SM. AT THE SFC...SRLY WINDS WERE INCREASING OVER THE REGION
AHEAD OF TROUGH THAT EXTENDED FROM NW ONTARIO INTO MN.
WITH LIGHT WINDS OVER LAKE MICHIGAN AND LAND BREEZES BECOMING MORE
PROMINENT...MID LAKE LES HAD DEVELOPED OFFSHORE FROM NW LOWER MI.
MAIN FCST CONCERNS ARE LAKE EFFECT SNOW TRENDS/AMOUNTS OFF OF LAKE
MICHIGAN TODAY AND INTO THE KEWEENAW TONIGHT.
TODAY...AS THE MOISTURE AND LIGHT PCPN ASSOCIATED WITH THE SHRTWVS
ADVANCE TO THE EAST AND CONVERGENT SRLY FLOW INCREASES ACROSS LAKE
MICHIGAN...MDLS SUGGEST THAT A DOMINANT LES BAND IS LIKELY TO
DEVELOP. THE HIGH RES MODELS CONSENSUS ALSO INDICATE THAT THE BAND WOULD
LIKELY MOVE ONSHORE EAST OF ISQ AND SPREAD QUICKLY TO THE NORTH AND
EAST INTO LUCE COUNTY BY MID MORNING. ALTHOUGH CONFIDENCE IS HIGH
THAT A BAND WILL MOVE INTO EASTERN UPPER MICHIGAN...THERE IS STILL
UNCERTAINTY WITH THE DETAILS OF TIMING/LOCATION OF THE BAND. WITH A
LONG FETCH ACROSS THE LAKE...AND MODERATE INSTABILITY (850 MB TEMP
OF -11C AND LAKE SFC NEAR 6C)...MODERATE TO STRONG CONV...AND
INVERSION HEIGHTS TO AROUND 10K FT...SNOWFALL INTENSITY SHOULD
BECOME HEAVY AT TIMES. EVEN IF 1-2 INCH PER HOUR SNOWFALL RATES
DEVELOP...THE STEADY EASTWARD PROGRESSION SHOULD LIMIT LCL MAX SNOW
AMOUNTS TO AROUND 4 INCHES. SO...AN LES ADVY WAS POSTED FOR SRN
SCHOOLCRAFT AND LUCE COUNTIES.
OTHERWISE...THE BEST CHANCE FOR ADDITIONAL FLURRIES OR LIGHT SNOW
SHOWERS THIS AFTERNOON WILL BE OVER THE WRN CWA AS YET ANOTHER WEAK
SHRTWV MOVES FROM WRN MN MOVES TOWARD THE AREA.
TONIGHT...THE NW ONTARIO TROUGH WILL MOVE TO THE EAST DRAGGING A
COLD FRONT INTO WRN LAKE SUPERIOR. THE COLDER AIR ALONG WITH WINDS
VEERING WRLY WILL PROVIDE FAVORABLE CONDITIONS FOR LES INTO THE
KEWEENAW. WITH 850 MB TEMPS DROPPING TO AROUND -14C...INVERSION
HEIGHTS AROUND 7K FT...AND LOW LEVEL CONVERGENCE STRENGTHENING
DOWNWIND FROM THE APOSTLE ISLANDS...A MODERATE TO HEAVY LES BAND IS
EXPECTED TO DEVELOP. SNOWFALL AMOUNTS OF AT LEAST 2 TO 4 INCHES ARE
LIKELY...ESPECIALLY IN THE HIGHER TERRAIN FROM TWIN LAKES TO CALUMET.
SINCE THERE STILL IS UNCERTAINTY WITH THE DURATION AND LOCATION OF
THE MAIN LES BAND(S)...NO HEADLINE WAS ISSUED AT THIS TIME.
SUBSIDENCE WITH QUICKLY LOWERING INVERSION HEIGHTS AND DIMINISHING
LES INTENSITY IS EXPECTED AFTER MIDNIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM EST TUE DEC 11 2012
AS STRONG H3 JET REFOCUSES OVER EASTERN SEABOARD BY THURSDAY...
EXPECT AMPLIFIED TROUGHING CURRENTLY IN PLACE OVER MUCH OF CONUS
TO TRANSITION TO SPLIT ZONAL FLOW. NORTHERN PLAINS AND UPPER GREAT
LAKES WILL BE AFFECTED BY NORTHERN STREAM THROUGH REST OF THE WORK
WEEK. DISTURBANCES IN THE NORTHERN STREAM NOT FORECAST TO BE ALL
THAT STRONG AND SINCE MAJORITY THE ENERGY FROM STRONGER SHORTWAVES
STAYS MORE OVER CANADA...EXPECT ONLY MINOR IMPACT TO SENSIBLE WX OVR
LAKE SUPERIOR AND UPR MICHIGAN.
A BIT OF LK EFFECT SNOW TO CONTEND WITH OVER THE KEWEENAW TO OPEN
THE LONG TERM PERIOD ON WEDNESDAY MORNING. KEPT 20 POPS IN THROUGH
MID MORNING...BUT THE SUBSIDENCE/DRYING AOA 850MB/LOWERING INVERSION
AND QUICKLY BACKING BLYR FLOW WILL END ANY WHATEVER LK EFFECT
LINGERS PAST 12Z IN SHORT ORDER. ATTN THEN TURNS TO LEAD WAVE
ZIPPING ALONG US/CANADIAN BORDER LATER WEDNESDAY IN INCREASINGLY
ZONAL FLOW. LARGER SCALE DYNAMICS WITH THE WAVE /H7-H5 Q-VECTOR
CONVERGENCE AND LEFT EXIT REGION JET FORCING/ STAYS MOSTLY OVER
ONTARIO WEDNESDAY AFTN AND WEDNESDAY NIGHT. ONLY MODELS THAT GRAZE
NORTHERN CWA /KEWEENAW AND LUCE COUNTY/ WITH QPF ARE THE 00Z
CANADIAN GEM-NH AND UKMET. OTHER MODELS ARE QUITE DRY BLO THE CLOUD
BASE AROUND H7...SO IT TAKES UNTIL PARCELS REACH OVER NORTHERN LK
SUPERIOR/NORTHERN ONTARIO TO SATURATE/PRECIPITATE. DID NOT WANT TO
COMPLETELY IGNORE GEM-NH AND UKMET...BUT KEPT POPS IN THE FAR NORTH
NO MORE THAN 20 PCT. BEGINNING TO THINK THAT INSTEAD OF PRECIP THAT
GUSTY SW WINDS AND STEADY TEMPS IN THE UPR 20S TO MID 30S MAY BE
MAIN PRIMARY RESULT FROM THIS INITIAL WAVE. H925-H85 WINDS 35-45 KTS
ALONG WITH NEUTRAL TO SLIGHLY UNSTABLE TEMPERATURE PROFILE SFC-H9
ALONG WITH PRESSURE FALLS OVR LK SUPERIOR AND INTO ONTARIO MAY
RESULT IN AREAS NEAR LK SUPERIOR OVR NCNTRL UPR MICHIGAN...NEAR LK
MICHIGAN AND OVER MUCH OF EASTERN CWA GUSTING SEEING WINDS GUSTING
20-35 MPH THROUGH THE NIGHT WITH MINIMAL TEMP FALL. WENT WITH
NON-DIURNAL TEMP TREND TO COVER THIS POSSIBILITY.
LEAD WAVE HEADS TOWARD QUEBEC BY DAYBREAK THURSDAY AS SFC TROUGH
EASES ACROSS LK SUPERIOR/NORTHERN UPR MICHIGAN. ANOTHER WAVE IS
LURKING UPSTREAM IN THE QUICK ZONAL FLOW ALOFT. UKMET/GEM-NH
STRONGEST WITH WAVE...GFS/ECMWF NOT SO MUCH. SINCE THE LOW-LEVEL
TROUGH BECOMES PARALLEL WITH UPPER FLOW...NOT TOO KEEN ON PUSHING
TROUGH AS FAR SOUTH AS GEM-NH HAS IT BY THURSDAY AFTN. INSTEAD KEPT
BOUNDARY HUNG UP OVR KEWEENAW WITH JUST A SMALL CHANCE OF SNOW
SHOWERS BY AFTN AS SHALLOW COLD AIR TRIES TO SETTLE BACK ACROSS
NORTHERN CWA. TEMPS AHEAD OF FRONT...WHEREVER IT ENDS UP...COULD
GET FAIRLY WARM WITH READINGS WELL INTO THE 30S...ESPECIALLY EAST.
FOR THURSDAY NIGHT INTO FRIDAY...MAY BE SETTING UP FOR ANOTHER
DZ/FZDZ OR SNOW SCENARIO. GFS IS COLDER...BUT GFS/ECMWF/GEM-NHEM
INDICATE H85 TEMPS BORDERLINE TO GET ICE NUCLEATION/SNOW. ALSO GFS
AND ECMWF INDICATE A LOT OF LOW-LEVEL MOISTURE BUT NOT AS MUCH H85
MOISTURE. INTRODUCED SOME DZ/FZDZ FOR FRIDAY AND FRIDAY NIGHT
BETWEEN THE TROUGH THAT DROPS THROUGH LATE THURSDAY AND OUT AHEAD
OF STRONGER LOW PRESSURE SYSTEM MOVING INTO REGION NEXT WEEKEND.
UPSLOPE NE THEN SE WINDS WOULD ONLY HELP OUT THE DZ/FZDZ.
AS FLOW BECOMES SPLIT LATE THIS WEEK...STRONG SOUTHERN STREAM WAVE
TAKES SHAPE OVER DESERT SOUTHWEST. IT IS THIS WAVE THAT BECOMES MAIN
INSTIGATOR FOR LEE ROCKIES CYCLOGENESIS LATE FRIDAY INTO SATURDAY.
THIS SOUTHERN STREAM WAVE/ASSOCIATED SFC LOW ARE FORECAST TO EJECT
OUT OF SOUTHERN PLAINS INTO WESTERN GREAT LAKES OR OHIO VALLEY TO
END THE WEEKEND. FLOW PATTERN BECOMES QUITE MESSY THOUGH AS ANOTHER
WAVE WILL BE QUICKLY FOLLOWING INTO SOUTHERN PLAINS AND THERE IS
EVEN A WAVE IN THE NORTHERN STREAM THAT WILL TRY TO MAKE A RUN INTO
THE NORTHERN PLAINS...THOUGH IT DOES SEEM AT LEAST AT THIS POINT...
THAT THAT WAVE MAY GET DEFLECTED OFF INTO CANADA AWAY FROM THE FRAY.
ALL THE WAVES PROBABLY WILL END UP INTERACTING WITH EACH OTHER IN
SOME FORM OR ANOTHER. NET RESULT IS A NOT SO CLEAR CUT FORECAST OF
THE SFC LOW/THERMAL PROFILE/PRECIPITATION COVERAGE AND INTENSITY
ACROSS UPPER LAKES REGION LATER SATURDAY INTO SUNDAY. ONLY REAL
MODEL TREND OF NOTE IS GFS HAS TRENDED TOWARD ECMWF IDEA OF A MORE
CLOSED OFF SOUTHERN STREAM/SFC LOW SINCE THE 18Z RUN ON MONDAY AFTN.
TROUBLE IS THAT THIS WAVE IS STILL OVER GULF OF ALASKA THIS MORNING
AND REALLY WILL NOT BE ONSHORE OVER CONUS FOR BETTER ROAB SAMPLING
UNTIL LIKELY FRIDAY MORNING AT THE EARLIEST. EXPECT UNCERTAINTY TO
CLOUD THE FORECAST UNTIL THAT POINT WITH THE SPECIFICS OF THE TRACK
OF SFC LOW. A CONSENSUS WAS RETAINED FOR POPS NOW. FOR OVERALL PTYPE
LEANED ON LARGE SCALE THICKNESSES...THOUGH WHERE FLOW WAS ONSHORE
OFF THE GREAT LAKES...KEPT SOME MENTION OF RAIN AS WELL WITH TEMPS
EXPECTED TO BE IN THE MID 30S. LINGERED CHANCE POPS FOR MAINLY SNOW
OVER THE EAST ON SUNDAY. NOT A LOT OF COLD AIR FCST TO BE AROUND IN
WAKE OF THE MAINLY SOUTHERN STREAM ORIGIN SYSTEM...SO KEPT POPS FOR
ANY LK EFFECT INTO MONDAY ON THE LOW SIDE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1222 AM EST TUE DEC 11 2012
THERE IS VERY MUCH UNCERTAINTY ON THE EVOLUTION OF THE LO CLDS OVER
UPR MI EARLY THIS MRNG. THESE CLDS HAVE PROVEN TO BE MORE TENACIOUS
THAN EARLIER EXPECTED...WITH MVFR AND EVEN SOME IFR CONDITIONS STILL
PRESENT TO THE SSW. SO TENDED TO BE MORE PESSIMISTIC WITH CIG FCSTS
DESPITE PASSAGE OF SFC HI PRES RDG/WSHFT TO THE SSW. BY LATER IN THE
MRNG...SUSPECT DRIER AIR NOW OVER MN WL MOVE INTO THE AREA WITH
INCRSG SW FLOW AHEAD OF APRCHG LO PRES TROF. ALTHOUGH SOME MVFR
CONDITIONS MIGHT IMPACT CMX/IWD IN THE AFTN AS THIS TROF CLOSES
IN...LIMITED LLVL MSTR RETURN WL LIKELY LEAD TO A PERSISTENCE OF
MAINLY VFR WX. FOLLOWING THE TROF PASSAGE/WSHFT TO THE W IN THE
EARLY EVNG...EXPECT SOME SHSN TO IMPACT THE EXPOSED KEWEENAW
PENINSULA...WITH IFR CONDITIONS LIKELY AT CMX. DOWNSLOPE NATURE OF W
WIND BEHIND THIS TROF PASSAGE WL LIKELY MAINTAIN VFR CIGS AT SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST TUE DEC 11 2012
WINDS 25 KTS OR BLO THROUGH MIDDAY WEDNESDAY THEN EXPECT INCREASING
SOUTH TO SOUTHWEST WINDS LATE WEDNESDAY/WEDNESDAY NIGHT AND INTO
EARLY THURSDAY MORNING. GALES LIKELY OVER EASTERN PORTIONS OF LAKE
SUPERIOR SO HAVE ISSUED GALE WATCH. TROUGH DROPS ACROSS THE LAKE BY
THURSDAY EVENING. WINDS WILL DIMINISH SIGNIFICANTLY THURSDAY NIGHT
INTO FRIDAY IN WAKE OF THIS TROUGH. LOW PRESSURE SYSTEM DEVELOPING
IN THE PLAINS PUSHES INTO WESTERN GREAT LAKES LATE SATURDAY INTO
SUNDAY WHILE HIGH PRESSURE MOVES ACROSS NEW ENGLAND. WINDS SHOULD
INCREASE FROM THE EAST ON SATURDAY OVER LAKE SUPERIOR. EXACT TRACK
AND DEPTH OF SFC LOW REMAINS UNCERTAIN THOUGH...SO DID NOT GO STRONG
ON WINDS AT THIS TIME. POSSIBLE THAT WINDS MAY EVENTUALLY NEED TO BE
INCREASED COMPARED TO WHAT IS IN THE CURRENT FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ014.
LAKE EFFECT SNOW ADVISORY FROM 9 AM THIS MORNING TO 3 PM EST
THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY EVENING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ265>267.
LAKE MICHIGAN...
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LMZ248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
951 AM EST TUE DEC 11 2012
.SYNOPSIS...
A WESTERLY FLOW OF SEASONABLY COLD AIR WILL PREVAIL THROUGH MID-
WEEK...ALONG WITH MAINLY DRY WEATHER...AS HIGH PRESSURE GRADUALLY
BUILDS INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
953 AM UPDATE...
STRONG COLD AIR ADVECTION CONTINUES THIS MORNING. LOW LEVEL DRY
AIR AND SHEAR IS WORKING TO UNDERMINE ATTEMPTS AT LES OFF OF
ONTARIO, SO CONTINUE TO EXPECT LITTLE IN THE WAY OF SNOW
ACCUMULATION.
TEMPS WON`T RISE MORE THAN A FEW DEGREES FROM CURRENT LEVELS, PER
PREVIOUS FORECAST. WE HAVE INCREASED SKY COVER IN GRIDS THROUGH
THIS EVENING HOWEVER, AS DENSE CLOUD COVER EXTENDS WELL INTO
ONTARIO PROVINCE AND OHIO. LATEST RAP SOUNDINGS SUGGEST MAINLY
CLOUDY SKIES FOR INTERIOR FA THROUGH MIDNIGHT.
4 AM TUE UPDATE... MAIN PCPN SHIELD CONTS TO QUICKLY EXIT EARLY
THIS MRNG...AS AN UPR-LVL WAVE LIFTS INTO NEW ENG...AND A SFC COLD
FRNT PUSHES OFF THE EAST COAST.
IN THE WAKE OF THE AFOREMENTIONED SYSTEMS...A W TO NW FLOW AND STG
LOW-LVL CAA WILL PREVAIL FOR THE REST OF THE MRNG HRS.
HOWEVER...DESPITE THIS SYNOPTIC SET-UP...THE LAKE RESPONSE SHOULD
BE LIMITED...AS PRONOUNCED DRY ADVECTION OCCURS ABV 900 MB...AND
THE MIXED LYR FLOW REMAINS FAIRLY SHEARED IN A DIR SENSE.
THUS...WE EXPECT NOTHING MORE THAN SCTD -SHSN/FLRYS...WITH LIMITED
ACCUMS (UNDER AN INCH) ACRS THE MOHAWK VLY/SRN TUG HILL RGN.
FROM THE TWIN TIERS SWD...AM CLDS SHOULD BREAK FOR SOME AFTN
SUNSHINE...WITH STG DRYING/DVM AT PLAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
415 AM UPDATE... QUIET WX TO PREVAIL THIS PD.
WRLY LOW-LVL FLOW PERSISTS TNT...WED...AND INTO WED EVE.
AGN...THOUGH...SHALLOW MOIST/POOR DZ MECHANICS AND DIR SHEAR IN
THE VERTICAL SHOULD SERIOUSLY MUTE ANY LAKE RESPONSE. THE "BEST"
COVERAGE OF SHSN COULD OCCUR WED AFTN INTO THE EARLY EVE IN OUR
FAR NRN ZNS...AS A PROGRESSIVE NRN STREAM UPR WAVE COMES
THROUGH...ALG WITH A WEAK SFC TROUGH. VERY MINOR ACCUMS...IF
ANY...ARE FORESEEN.
BY THU...RIDGING COMES IN...ALG WITH BACKING LOW-LVL FLOW AND WAA.
THUS...HIGH TEMPS SHOULD MODERATE INTO THE LWR 40S MANY LOCALES BY
THU AFTN.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
4 AM UPDATE...
NOT MANY CHANGES TO THE EXTENDED. MAIN FOCUS WILL BE ON THE
SATURDAY NIGHT THROUGH SUNDAY PERIOD WITH THE POTENTIAL OF MIXED
PRECIP ACROSS THE AREA. WHILE THE 0Z GFS AND EURO DIFFER ON WHEN
THE PRECIP ARRIVES IN OUR AREA LATE SATURDAY NIGHT/EARLY
SUNDAY...BOTH MODELS ARE CONSISTENT IN SHOWING ENOUGH COLD AIR
AROUND FOR A WINTRY MIX FOR PART OF SUNDAY. MAIN PLAYER WILL BE A
1030 MB HIGH REMAINING ANCHORED OVER QUEBEC WHICH WILL HELP TO
LOCK ANY COLD AIR AROUND WHILE A LOW PRESSURE SYSTEM MOVES OUT OF
THE OHIO VALLEY. IT APPEARS WE SHOULD HAVE ENOUGH COLD AIR AROUND FOR
AT LEAST A BRIEF WINTRY MIX OVER MOST OF THE AREA SUNDAY. IT MAY
LAST MUCH LONGER OVER THE NORMALLY COLDER SPOTS OVER THE FAR EAST
WITH BOTH MODELS SHOWING 925 TEMPS BELOW 0C THROUGH 0Z MONDAY. IF
THIS TREND CONTINUES ADDITIONAL WORDING MAY BE ADDED TO THE HWO IN
THE COMING DAYS. THE PREVIOUS AFD IS BELOW...
THU THRU SAT PD DOMINATED BY A FLAT RDG WITH NEAR OR
SLGTLY ABV NRML TEMPS. DRY AIR WITH THE RDG WILL KEEP SKIES PTLY
CDY AT WORST...WITH WITH WLY FLOW AND MRGNL TEMPS KEEPING ANY LE
OUT OF THE AREA. CHGS BEGIN LATE SAT INTO SUN AS A SYSTEM MVES
INTO THE MIDWEST. CNSDRBL DFRNCS BETWEEN THE OPERATIONAL MODELS
WITH THE ECMWF WINDING UP A DEEPER LOW WEST OF THE AREA PUMPING UP
THE RDG AND DVLPG STRONGER WAA. THE GFS MORE QUICKLY TRANSFERS
ENERGY TO THE ERN SYSTEM KEEPING THE AREA COLDER AND BRINGING A
CHANCE OF MIXED PCPN. HPC GUID TENDS TO FOLLOW THE EURO SOLN AND
IS MILDER. FOR THE GRIDS...LEANED TWRDS HPC AND THE EURO BUT DID
LWR TEMPS A FEW DEGREES TO BETTER BLEND WITH SURROUNDING OFFICES
WHICH SEEM TO FVR THE GFS. COOLER MON WITH AN UPR LOW NORTH OF THE
LAKES AND A NW FLOW...BUT STILL NEAR SEASONAL TEMPS.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
640 AM UPDATE...
LOW END MVFR CIGS THIS MORNING WILL GRADUALLY RISE TO VFR BY LATE
MORNING DRIER AIR MOVES IN FROM THE WEST. THIS PROCESS WILL BE
FASTEST AT KAVP WITH VFR POSSIBLE IN THE NEXT HOUR OR TWO. FARTHER
NORTH A BIT MORE TRICKY OF A CALL. BASED ON MODEL SOUNDINGS WE
SHOULD BE SEEING VFR CIGS WITHIN THE HOUR. HOWEVER WE HAVE PLENTY
OF MVFR BACK ACROSS WESTERN NY AND AS THE FLOW BACKS MORE INTO THE
WEST...IT MAKES SENSE THAT THE CIGS MAY TAKE LONGER TO RISE THAN
WHAT THE MODELS INDICATE. BKN CIGS AROUND 5KFT THIS AFTERNOON WITH
A CLEARING SKY EXPECTED TONIGHT.
WNW WINDS 5 T0 1O KTS THROUGH THIS AFTERNOON BECOMING
LIGHT/VARIABLE TONIGHT.
OUTLOOK...
TUE NGT-SAT...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...DGM/HEDEN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
351 PM EST TUE DEC 11 2012
.DISCUSSION...
TONIGHT...LATEST RAP ANALYSIS SHOWS THE H85-H50 FLOW HAS BECOME
PARALLEL TO THE ORIENTATION OF THE APPROACHING COLD FRONT...A SET UP
THAT SHOULD FORCE IT TO STALL OVER N FL OVERNIGHT. INDEED... FORWARD
MOTION HAS DECREASED OVER THE PAST SVRL HRS. INTERACTION BTWN THE
FRONTAL TROF AND AN H100-H70 RIDGE AXIS OVER CUBA AN THE FL STRAITS
WILL GENERATE A STRONG AND DEEP SW FLOW ACRS CENTRAL FL. THESE WINDS
WILL TAP A DEEP MOISTURE BAND OVER THE SE GOMEX/YUCATAN CHANNEL AND
PULL IT ACRS THE AREA.
POCKETS OF ENHANCED MID LVL VORTICITY/OMEGA AND UPR LVL DIVERGENCE
NOTED WITHIN THE MOISTURE BAND. MODEL SOUNDINGS INDICATE PWAT VALUES
INCREASING TO 2.0" BY 06Z WITH STRAIT LINE HODOGRAPHS THRU DAYBREAK
ALONG AND N OF I-4...H85-H50 LAPSE RATES BTWN 6.0-6.5C/KM. LOSS OF
DAYTIME HEATING WILL REDUCE SFC BUOYANCY...BUT WITH SFC DEWPOINTS
REMAINING IN THE M60S/L70S... PRECIP CHANCES WILL BE HIGH ACRS E
CENT FL. ADDED DYNAMIC SUPPORT ALOFT WILL ENHANCE STORM POTENTIAL...
ESP WHERE MID/UPR LVL CLOUD COVER THINS OUT AND ALLOWS LATE AFTN
HEATING.
WILL GO WITH 80 POPS FROM NW OSCEOLA/N BREVARD NWD...DECREASING TO
60 POPS MARTIN/ST. LUCIE. WARM SW FLOW AND HIGH CLOUD COVER WILL
KEEP MIN TEMPS IN THE M/U60S...A SOLID 10-15F ABV CLIMO.
WEDNESDAY...LITTLE CHANGE TO THE WET WX PATTERN FOR MOST OF THE DAY
AS THE RIDGE OVER THE FL STRAITS CONTINUES TO INTERACT WITH THE
FRONTAL TROF STRUNG OUT ACROSS N FL. A MID LVL SHORT WAVE IS
EXPECTED TO BACK OVER THE SRN PLAINS WILL PUNCH ACRS THE DEEP
SOUTH/NORTHERN GOMEX AND INDUCE WEAK SURFACE LOW ALONG STALLED FRNTL
BNDRY. AS THE LOW PULLS INTO THE ATLC...IT WILL PROVIDE THE
NECESSARY TORQUE TO CRANK THE FRONT INTO CENTRAL FL BY LATE AFTN.
MODERATE TO STRONG UPPER LEVEL FORCING WILL REMAIN IN PLACE AS A
100-140KT LIFTING H25 JET EXTENDING FROM THE CANADIAN MARITIMES TO
THE NW GOMEX DRAGS ITS ASCENDING RIGHT REAR QUADRANT ACRS THE
PENINSULA. LOW LVL CONVERGENCE AHEAD OF THE FRONT COUPLED WITH
APPROACHING SHORTWAVE AND JET STREAK WILL SUPPORT 60-80 POPS THRU
THE DAY. SPC KEEPS CENTRAL FL UNDER A SEE TEXT FOR SVR WX FOR THE
PSBLY OF A FEW STRONG WIND GUSTS WITHIN STORMS. WHILE SOME SHOWERS
AND STORMS MAY CONTAIN HEAVY RAIN...FLOODING CONCERNS REMAIN MINIMAL
WITH ANNUAL PRECIP DEFICITS RANGING FROM 2" TO 12".
WED NIGHT-THURSDAY...SHOWER/STORM ACTIVITY LINGERING INTO WED
EVENING BEFORE PASSING SHORTWAVE HELPS PUSH THE FRONT DOWN THE
PENINSULA OVERNIGHT INTO EARLY THURSDAY. BRIEF COOLDOWN BEHIND THE
FRONT FOR THURSDAY BUT FLOW WILL QUICKLY TAKE ON AN ONSHORE
COMPONENT BY LATER IN THE DAY. HAVE SCATTERED POPS IN FOR EARLY WED
EVENING THEN JUST A SLIGHT POP SOUTHERN FOR COUNTIES THURSDAY
MORNING. LOW TEMPS WED NIGHT RANGING FROM THE MID 50S NORTHWESTERN
SECTIONS TO THE MID 60S SOUTHERN TREASURE COAST. DAYTIME HIGHS
THURSDAY IN THE LOWER 70S NORTH AND MID 70S SOUTHERN SECTIONS OF
EC FL.
PREVIOUS EXTENDED DISCUSSION FOLLOWS...
FRIDAY-MONDAY...THE SURFACE HIGH BEHIND THE FRONT WILL QUICKLY
STRING OUT ACROSS THE DEEP SOUTH AND WESTERN ATLANTIC BY THE END OF
THE WEEK...BRINGING THE FLOW AROUND TO THE EAST BY FRIDAY AND
MODERATING ANY POST-FRONTAL COOLDOWN.
BOTH THE GFS AND ECMWF SHOW ENOUGH LOW LEVEL MOISTURE THAT LOW
TOPPED ONSHORE MOVING SHOWERS MAY BE A POSSIBILITY FRIDAY NIGHT INTO
SATURDAY...HOWEVER WILL KEEP THE MENTION OUT OF THE FORECAST FOR NOW
AS THE EXACT TIMING/COVERAGE OF THESE CAN BE HARD TO PINPOINT MORE
THAN A DAY OR TWO OUT. BY SUNDAY TIMING DIFFERENCE ARISE BETWEEN THE
GFS AND ECMWF IN THE NEXT SHORTWAVE AND ACCOMPANYING SURFACE LOW
THAT MOVES ACROSS THE MIDWEST. HOWEVER BOTH INDICATE THE APPROACH OF
ANOTHER FRONTAL BOUNDARY IN THE SUNDAY/MONDAY TIMEFRAME AND HAVE
INTRODUCE ISOLATED SHOWERS INTO THE FORECAST FOR THOSE TWO DAYS.
SEASONABLE TEMPERATURES THROUGH THE PERIOD WITH HIGHS IN THE
MID-UPPER 70S AND LOWS IN THE 50S.
&&
.AVIATION...THRU 12/03Z...VCTS ALL SITES...AREAS MVFR CIGS...NMRS
MVFR SHRAS/SCT IFR TSRAS...LIFR CIGS/VSBYS ALNG THE COAST BTWN
KOMN-KTIX IN SEA FOG. BTWN 12/03Z-12-06Z...IFR CIGS DVLPG ALL SITES
CONTG THRU 12/18Z...AREAS LIFR CIGS/IFR VSBYS IN FG N OF
KMLB-KISM...MVFR VSBYS IN BR S OF KMLB-KISM.
&&
.MARINE...TONIGHT...LIGHT AND VARIABLE SFC/BNDRY LYR WINDS WILL
INCREASE OUT OF THE S/SW TO 10-15KTS OVERNIGHT AS THE APPROACHING
COLD FRONT STALLS OVER N FL. SEAS 2-3FT NEARSHORE AND 3-4FT
OFFSHORE. NMRS/WDSRPD SHRAS AND SCT TSRAS MOVING OFFSHORE...
INCREASED POTENTIAL FOR SFC G34KTS OR HIGHER
WEDNESDAY...MODERATE TO FRESH S/SW BREEZE THRU MOST OF THE DAY.
WNDSHFT TO W/NW BCMG GENTLE TO MODERATE N OF CAPE CANAVERAL BY MID
AFTN AS THE COLD FRONT BEGINS TO PUSH INTO THE CENTRAL PENINSULA.
SEAS 2-4FT NEARSHORE AND 3-5FT OFFSHORE. NMRS/WDSRPD SHRAS AND SCT
TSRAS MOVING OFFSHORE.
WED NIGHT/THURSDAY...FRONT PUSHES DOWN THE STATE WEDNESDAY NIGHT
INTO THURSDAY. BRIEF NORTHERLY WIND SURGE BEHIND THE FRONT WITH
WINDS PICKING UP NEAR 20KT BEFORE VEERING NORTHEAST AND DECREASING
BACK TO 15-20KT THURSDAY NIGHT. SEAS PICKING UP TO 5 FEET NEAR SHORE
AND UP TO 8 FEET WELL OFFSHORE BEHIND THE FRONT.
PREVIOUS EXTENDED DISCUSSION...
FRI-SUN...PROGRESSIVE FLOW PATTERN WILL BE IN PLACE THROUGH THE
WEEKEND AS THE SURFACE HIGH PUSHES ACROSS THE DEEP SOUTH AND OFF THE
MID ATLANTIC COAST...BRINGING WINDS AROUND TO THE EAST FOR FRIDAY AT
AROUND 15KTS...WITH SPEEDS DROPPING TO AROUND 10KTS INTO SATURDAY AS
THE RIDGE AXIS SINKS FURTHER SOUTH THROUGH THE STATE. BY
SUNDAY...WIND ARE FORECAST TO VEER TO THE SOUTH AND SOUTHWEST AS THE
RIDGE CONTINUES ITS SOUTHERLY MOVEMENT IN ADVANCE OF ANOTHER SYSTEM
MOVING INTO THE SOUTHEAST. DEPENDING ON THE TIMING OF THE NEXT
FRONT...SOUTH-SOUTHWEST WINDS COULD INCREASE TO 15-20KTS BY LATE
SUNDAY AFTERNOON.
WITH WINDS CONTINUING TO VEER THROUGH THE PERIOD...THERE WILL NOT BE
ENOUGH TIME FOR A LONG FETCH TO SET UP AND SEAS ARE EXPECTED TO
SLOWLY SUBSIDE FROM 7-8FT OFFSHORE FRIDAY TO 5-6FT BY SAT EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 65 74 57 72 / 80 90 40 10
MCO 66 79 58 75 / 80 70 40 10
MLB 69 79 61 76 / 70 70 50 20
VRB 68 80 62 77 / 70 60 50 20
LEE 64 75 54 73 / 80 80 40 10
SFB 66 77 58 74 / 80 80 40 10
ORL 66 78 58 74 / 80 80 40 10
FPR 68 80 62 77 / 60 60 50 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM....GLITTO
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1238 PM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A FRONT WILL CONTINUE TO BE STALLED NEAR THE COAST. THE FRONT WILL
BE PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL SHORTWAVE
TROUGH OVER THE GULF OF MEXICO SHOULD RESULT IN A MOISTURE
INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS INCREASE. THERE
MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE POPS WITH THE
GREATEST CHANCE IN THE SOUTHEAST PART.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
WEDNESDAY IS A CHALLENGING FORECAST IN TERMS OF PLACEMENT OF POPS.
THERE SHOULD BE A SIGNIFICANT EAST/WEST GRADIENT IN MOISTURE...POP
AND QPF. HAVE FORECAST POP TO RANGE FROM 20-30 PERCENT FAR WEST
CWA TO 80-90 PERCENT FAR EAST. THIS DUE TO FRONTAL ZONE OVER THE
AREA AND LOW PRESSURE MOVING NORTH OFF THE COAST DURING THE DAY AS
AN UPPER LEVEL SHORT WAVE APPROACHES THE AREA. THE SHORT WAVE WILL
CROSS THE AREA WEDNESDAY NIGHT AND MOISTURE/PRECIPITATION WILL
MOVE EAST. SKIES WILL CLEAR THURSDAY MORNING AND THE PERIOD
THURSDAY THROUGH FRIDAY NIGHT WILL BE DRY AND MOSTLY CLEAR AS HIGH
PRESSURE BUILDS OVER THE AREA. TEMPERATURES SHOULD BE CLOSE TO
GUIDANCE VALUES.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE AREA ON SATURDAY WILL MOVE OFF THE COAST ON
SUNDAY. THE MODELS SHOW A MOISTURE INCREASE SUNDAY AS A COLD FRONT
MOVES INTO THE AREA FROM THE WEST. WILL INCREASE POPS TO 20-35
PERCENT SATURDAY NIGHT INTO SUNDAY NIGHT TO ACCOUNT FOR POSSIBLE
SHOWER ACTIVITY ASSOCIATED WITH THE FRONT. MODELS DEVELOP A LOW
PRESSURE SYSTEM AHEAD OF A CLOSE UPPER LOW OVER THE SOUTHERN
PLAINS. THIS IS FORECAST IN THE MONDAY/TUESDAY TIME FRAME WITH THE
GFS FASTER THAN THE ECMWF. WILL INCREASE POPS AGAIN ON TUESDAY
INTO THE 30 PERCENT RANGE BUT THERE IS HIGH UNCERTAINTY AT THIS
TIME WITH RESPECT TO THIS FEATURE...ESPECIALLY THE TIMING. EXPECT
TEMPERATURES ABOVE NORMAL THROUGH SUNDAY THEN CLOSER TO NORMAL
MONDAY AND TUESDAY AFTER THE FRONTAL PASSAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A COLD FRONT WILL CONTINUE TO PUSH EASTWARD THIS AFTERNOON ALLOWING
DRIER AIR TO ENTER THE REGION. THE FRONT WILL STALL OFFSHORE OVERNIGHT
AND LOW PRESSURE WILL DEVELOP ON THE FRONT LATE TONIGHT AND CONTINUE
INTO WEDNESDAY. THIS WILL BRING DEEPER MOISTURE IN AFTER MIDNIGHT
AND WEDGE LIKE CONDITIONS ARE EXPECTED DURING THE DAY WEDNESDAY.
VFR CONDITIONS ARE EXPECTED INITIALLY WITH SCATTERED TO BROKEN CLOUDS
8-10 KT FT. CIGS WILL LOWER TO 3-4 KFT AFTER MIDNIGHT AND MVFR CIGS
NEAR 2 KFT SHOULD BECOME WIDESPREAD BY 12Z WEDNESDAY MORNING. EXPECT
MAINLY VFR VSBYS THIS AFTERNOON THROUGH THE OVERNIGHT PERIOD AS CLOUD
COVER INCREASES ALTHOUGH GFS AND NAM MOS GUIDANCE BROUGHT IFR-MVFR
VSBYS IN FOG WEDNESDAY MORNING WHILE GFS LAMP GUIDANCE HAD NONE WITH
A GOOD AMOUNT OF CLOUD COVER. LEANED MORE TOWARD THE LAMP GUIDANCE
WITH VERY LITTLE FOG. RAIN CHANCES EXPECTED TO INCREASE WEDNESDAY
MORNING BUT DECIDED TO JUST SAY SHOWERS IN THE VICINITY DUE TO
UNCERTAINTY AS TO LOCATION AND TIMING. BUT LIGHT RAIN IS POSSIBLE
BY LATE WEDNESDAY MORNING AND EARLY AFTERNOON AND THIS COULD RESTRICT
VSBYS TO THE MVFR CATEGORY.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1233 PM EST TUE DEC 11 2012
.SYNOPSIS...
A FRONTAL ZONE WILL REMAIN NEAR THE COAST THROUGH WEDNESDAY NIGHT.
A SERIES OF LOW PRESSURE SYSTEMS WILL MOVE NORTHEASTWARD ALONG THE
FRONT. THE LAST IN THE SERIES OF LOWS IS FORECAST TO BEGIN LIFTING
NORTHEAST OF THE AREA WEDNESDAY NIGHT. DRY AND COOL HIGH PRESSURE
WILL FOLLOW FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A FRONT WILL CONTINUE TO BE STALLED NEAR THE COAST. THE FRONT WILL
BE PARALLEL TO THE SOUTHWEST FLOW ALOFT. A MID-LEVEL SHORTWAVE
TROUGH OVER THE GULF OF MEXICO SHOULD RESULT IN A MOISTURE
INCREASE LATER THIS AFTERNOON. THE RAP SHOWS THIS INCREASE. THERE
MAY BE ENOUGH MOISTURE FOR RAIN. FORECASTED CHANCE POPS WITH THE
GREATEST CHANCE IN THE SOUTHEAST PART.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
WEDNESDAY IS A CHALLENGING FORECAST IN TERMS OF PLACEMENT OF POPS.
THERE SHOULD BE A SIGNIFICANT EAST/WEST GRADIENT IN MOISTURE...POP
AND QPF. HAVE FORECAST POP TO RANGE FROM 20-30 PERCENT FAR WEST
CWA TO 80-90 PERCENT FAR EAST. THIS DUE TO FRONTAL ZONE OVER THE
AREA AND LOW PRESSURE MOVING NORTH OFF THE COAST DURING THE DAY AS
AN UPPER LEVEL SHORT WAVE APPROACHES THE AREA. THE SHORT WAVE WILL
CROSS THE AREA WEDNESDAY NIGHT AND MOISTURE/PRECIPITATION WILL
MOVE EAST. SKIES WILL CLEAR THURSDAY MORNING AND THE PERIOD
THURSDAY THROUGH FRIDAY NIGHT WILL BE DRY AND MOSTLY CLEAR AS HIGH
PRESSURE BUILDS OVER THE AREA. TEMPERATURES SHOULD BE CLOSE TO
GUIDANCE VALUES.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE AREA ON SATURDAY WILL MOVE OFF THE COAST ON
SUNDAY. THE MODELS SHOW A MOISTURE INCREASE SUNDAY AS A COLD FRONT
MOVES INTO THE AREA FROM THE WEST. WILL INCREASE POPS TO 20-35
PERCENT SATURDAY NIGHT INTO SUNDAY NIGHT TO ACCOUNT FOR POSSIBLE
SHOWER ACTIVITY ASSOCIATED WITH THE FRONT. MODELS DEVELOP A LOW
PRESSURE SYSTEM AHEAD OF A CLOSE UPPER LOW OVER THE SOUTHERN
PLAINS. THIS IS FORECAST IN THE MONDAY/TUESDAY TIME FRAME WITH THE
GFS FASTER THAN THE ECMWF. WILL INCREASE POPS AGAIN ON TUESDAY
INTO THE 30 PERCENT RANGE BUT THERE IS HIGH UNCERTAINTY AT THIS
TIME WITH RESPECT TO THIS FEATURE...ESPECIALLY THE TIMING. EXPECT
TEMPERATURES ABOVE NORMAL THROUGH SUNDAY THEN CLOSER TO NORMAL
MONDAY AND TUESDAY AFTER THE FRONTAL PASSAGE.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
COLD FRONT PUSHING THROUGH THE AREA THIS MORNING WITH DRIER AIR
WORKING IN FROM THE WEST. THIS HAS BROUGHT MAINLY VFR CIGS ABOVE
3 KFT TO THE TAF SITES. HOWEVER...IR SATELLITE SHOWS DEEPER MOISTURE
MOVING NORTHEAST FROM THE GULF AND THIS MAY LOWER CIGS BACK BELOW
3 KFT LATER THIS AFTERNOON OR EARLY THIS EVENING. SINCE TIMING IS
AN ISSUE...DECIDED TO KEEP VFR CONDITIONS DURING THIS TIME PERIOD.
SOUTHWESTERLY FLOW ALOFT WILL KEEP A BLANKET OF MID AND HIGH
CLOUDS OVER THE AREA THROUGH THE FORECAST PERIOD. WINDS WILL BE
FROM THE WEST AROUND 5 TO 8 KNOTS THROUGH THE DAY BEFORE
DIMINISHING AND TURNING MORE NORTHERLY LATE IN THE FORECAST
PERIOD. SOME ISOLATED SHOWERS CANNOT BE RULED OUT BUT EVEN IF RAIN
DOES OCCUR IT SHOULD NOT RESULT IN ANY REDUCTION OF VSBYS/CIGS.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN SHOWERS
ASSOCIATED WITH A WAVE OF LOW PRESSURE LIFTING NORTHWARD TONIGHT
AND WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1020 AM MST TUE DEC 11 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
04Z WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED BROAD TROUGHING
ACROSS MUCH OF THE CONUS. PV ANALYSIS INDICATED SHORT WAVE TROUGH
MOVING INTO NORTHERN COLORADO...WITH AREA OF LIGHT SNOW OCCURRING TO
THE SOUTHWEST OF MAIN ANOMALY. AT THE SFC...HIGH PRESSURE WAS
CENTERED ACROSS THE AREA WITH AREA OF VERY LOW DEWPOINTS NOTED
ACROSS SOUTHWEST KANSAS...WITH HIGHER DEWPOINTS MOVING INTO THE AREA
FROM THE NORTH. 00Z RAOBS UPSTREAM OF THE AREA INDICATED MUCH
HIGHER LAPSE RATES THAN 24 HOURS AGO...AND WHILE LAPSE RATES WERE
NOT DRY ADIABATIC THEY WOULD SUPPORT CONDITIONAL INSTABILITY OR
NEUTRAL CONDITIONS SHOULD SATURATION OCCUR.
MAIN FORECAST CONCERNS WILL BE LIGHT SNOW POTENTIAL THROUGH THE
EARLY MORNING HOURS FOLLOWED BUY RISING TEMPS AND FIRE WX POTENTIAL
THROUGH THURSDAY.
TODAY...INITIAL CONCERN WILL BE AREA OF LIGHT SNOW TO THE WEST OF THE
AREA OCCURRING AHEAD OF WEAK PV ANOMALY. RUC SEEMS TO BE ONLY NEAR
TERM MODEL THAT HAS CAUGHT ON TO THIS...ALTHOUGH PRECIP AREA LOOKS
TOO LARGE FOR WHAT IS OCCURRING. FROM WHAT I CAN TELL FROM THE POINT
SOUNDINGS...FORCED ASCENT REALLY CONCENTRATED IN THE LOW LEVELS
AROUND THE DGZ WHICH IS LOCATED AROUND H7. GIVEN THE OVERALL PATTERN
THINK PRECIP THREAT WILL CONTINUE UNTIL H8-H7 FLOW BECOMES MORE
NORTHWESTERLY LEADING TO WEAK CAA AFTER 09Z. THERE IS SOME
INSTABILITY TO WORK WITH...BUT BASED ON LATEST RADAR TRENDS SEEMS
DOUBTFUL THAT SIG SNOW AMOUNTS WOULD OCCUR IN CWA. OTHERWISE...THINK
PRECIP CHANCES WILL END QUICKLY WITH SKIES CLEARING THROUGH THE DAY
AS LARGE SCALE SUBSIDENCE MOVES OVER THE AREA BEHIND TROUGH.
TONIGHT-TOMORROW...SHORT WAVE RIDGE WILL AMPLIFY OVER THE AREA
DURING THE PERIOD BRINGING DRY CONDITIONS AND A FEW HIGH CLOUDS.
OVERALL DO NOT THINK CLOUDS WILL HAVE A BIG IMPACT ON
TEMPS...ALTHOUGH AM A LITTLE CONCERNED THAT STRONG H3 FLOW
PERPENDICULAR TO ROCKIES MAY CREATE AN ENHANCED AREA OF CIRRUS DURING
THE AFTERNOON. DESPITE THE LOW LEVEL WESTERLY FLOW...THE POTENTIAL
FOR HIGH CLOUD COVER AND LATEST ROUND OF OPERATIONAL DATA HAS
TEMPERED MY CONFIDENCE IN A SIG WARM UP SOMEWHAT AND HAVE LOWERED
HIGHS A FEW DEGREES ACROSS EASTERN CWA. FOR THE AREAS THAT DO MIX
OUT/WARM STRONGLY UPPER 50S AND AFTERNOON HUMIDITIES AROUND 15
PERCENT LIKELY. WILL HAVE NEAR CRITICAL FIRE WX CONDITIONS IN THIS
AREA...BUT NOT A LOT OF SUPPORT FOR STRONG WINDS EVEN WITH
DEVELOPING LEE TROUGH. CANNOT RULE OUT RED FLAG CONDITIONS
DEVELOPING...BUT CONFIDENCE TOO LOW IN WINDS MATERIALIZING TO ISSUE
WATCH ATTM.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 216 AM MST TUE DEC 11 2012
WED NIGHT-THUR NIGHT...SHORT WAVE RIDGE WILL BE PRIMARY INFLUENCE OF
WEATHER ACROSS THE CWA AS FLOW ALOFT BECOMES MORE AMPLIFIED IN
RESPONSE TO WEST COAST TROUGH. GIVEN THE PATTERN AND VERTICAL
MOISTURE/STABILITY PROFILES...SEE NO REASON WHY DRY CONDITIONS WILL
NOT CONTINUE THROUGH THE PERIOD. SHOULD SEE WARMING TREND THROUGH
THE PERIOD...ESPECIALLY IN OVERNIGHT LOWS. GENERALLY KEPT WELL ABOVE
NORMAL MAX T FORECAST GOING...ALTHOUGH AM A LITTLE CONCERNED THAT
LATEST GUIDANCE INDICATING WEAK FRONTAL ZONE MOVING THROUGH AREA
RESULTING IN LIGHT...BACKED WINDS THURSDAY.
FRIDAY-MONDAY...
MAIN FOCUS CONTINUES TO BE ON UPPER LOW WHICH IS EXPECTED TO DEVELOP
OVER THE SW US AND POSSIBLY IMPACT OUR CWA FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS HAS BEEN THE CASE THE LAST FEW DAYS THE
GEFS AND ECMWF CONTINUE TO SHOW LARGE SPREAD IN SOLUTIONS RUN TO RUN
FOR THIS SYSTEM...WITH THE OPERATIONAL GFS SLIGHTLY MORE CONSISTENT.
THIS TROUGH IS STILL SOUTH OF THE ALEUTIAN ISLANDS OVER THE NORTHERN
PACIFIC....AND UNTIL IT IS BETTER SAMPLED IT IS HARD FOR ME TO MAKE
LARGE CHANGES TO THIS FORECAST PERIOD. CONFIDENCE IS STILL HIGHEST
ACROSS OUR EASTERN CWA...THOUGH I HAVE EXPANDED CHANCE POPS FURTHER
WEST TO ACCOUNT FOR LATEST ECMWF TRENDS. OTHER COMPLICATING FACTOR
IS WAA ADVERTISED BY ECMWF AND GFS WHICH COULD DELAY SNOW CHANGE
OVER. CONSIDERING THE ABSENCE OF STRONG CAA BEHIND THIS SYSTEM...AND
RELIANCE ON EVAPORATIVE PROCESSES FOR CHANGE OVER I AM NOT CONFIDENT
THAT WE WOULD SEE LARGE SNOW ACCUMULATIONS EVEN WITH THE MOST
FAVORABLE TRACKS. I BUMPED UP THE LOW TEMP FORECAST TO LOW 30S
FRIDAY NIGHT AND THIS STILL MIGHT BE TOO COOL IF WE SEE THICK CLOUD
COVER.
SHORTWAVE RIDGING SHOULD KEEP CONDITIONS DRY SATURDAY AND SUNDAY. BY
MONDAY GFS/ECMWF ARE BOTH INDICATING ANOTHER TROUGH IMPACTING THE
HIGH/CENTRAL PLAINS...THOUGH THERE ARE SIGNIFICANT DIFFERENCES IN
EVOLUTION. I DECIDED TO KEEP SLIGHT CHANCE POPS IN PLACE MONDAY AS A
STARTING POINT...SINCE RAIN OR SNOW CANT BE RULED OUT WITH
ADVERTISED PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1016 AM MST TUE DEC 11 2012
VFR CONDITIONS EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF
PERIOD. SURFACE TROUGH OVER EASTERN COLORADO WILL KEEP WINDS
MAINLY OUT OF THE SOUTHWEST. A FEW HIGH CLOUDS WILL SPILL OVER THE
ROCKIES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...024
AREA FORECAST DISCUSSION
NWS JACKSON KY
307 PM EST TUE DEC 11 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 307 PM EST TUE DEC 11 2012
QUIET WEATHER IS ON TAP FOR THE NEXT SEVERAL DAYS AS HIGH PRESSURE
BUILDS INTO THE REGION TONIGHT AND TOMORROW. HOWEVER...THE MID LEVEL
TROUGH AXIS IS EXPECTED TO STALL JUST TO OUR NORTHWEST TONIGHT.
ONGOING CLOUD COVER WILL LIKELY PERSIST THROUGH TONIGHT AND PERHAPS
EVEN EXPAND BACK INTO AREAS IN THE SOUTHWEST THAT HAVE TEMPORARILY
CLEARED OUT THIS AFTERNOON. THIS MAY HAPPEN DUE TO LIGHT NORTHEAST
LOW LEVEL WINDS. AS MENTIONED EARLIER TODAY...THE CLEARING IN THE
SOUTHWEST WILL ALLOW THOSE AREAS TO BE THE COLDEST TONIGHT WITH LOW
BOTTOMING OUT AROUND 20 OR PERHAPS EVEN A FEW TEENS.
MEANWHILE...FURTHER NORTHEAST...THE CLOUDS WILL KEEP TEMPERATURES IN
THE MIDDLE TO UPPER 20S.
THE MID LEVEL RIDGE AXIS WILL FINALLY PUSH THROUGH EASTERN KENTUCKY
TOMORROW...WITH CLOUDS FINALLY GIVING WAY TO SUNSHINE. THIS WILL HELP
BOOST THE COOL EARLY MORNING READINGS INTO THE 40S BY THE AFTERNOON.
CLEAR SKIES WILL PERSIST INTO WEDNESDAY NIGHT SETTING UP A COLD NIGHT
FOR ALL OF EASTERN KENTUCKY. SEVERAL VALLEY LOCATIONS MAY SEE
TEMPERATURES IN THE TEENS WITH 20S ON THE RIDGES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 307 PM EST TUE DEC 11 2012
THE EXTENDED PERIOD BEGINS ON THURSDAY MORNING...WITH A LARGE AREA
OF HIGH PRESSURE DOMINATING THE WEATHER ACROSS EASTERN KENTUCKY
THROUGH FRIDAY NIGHT INTO EARLY SATURDAY MORNING. BOTH THE GFS AND
ECMWF MODELS ARE IN VERY GOOD AGREEMENT TO BEGIN THE PERIOD. THE
MODELS HAVE SUBTLE DIFFERENCES IN TIMING OF THE PASSAGE OF ANOTHER
WEATHER SYSTEM OVER THE WEEKEND...SO EITHER MODEL REALLY WOULD HAVE
BEEN A SUITABLE CHOICE FOR THE WEEKENDS WEATHER. HOWEVER...SINCE THE
ECMWF IS USUALLY THE MORE RELIABLE OF THE TWO MODELS...ITS SOLUTION
WAS PREFERRED. THE CONSENSUS IS FOR A WEAKENING COLD FRONT TO MOVE
ACROSS THE OHIO AND TENNESSEE VALLEYS SATURDAY AND SATURDAY NIGHT.
IT APPEARS THAT THE FRONT BEGINS TO SHEAR OUT AS IT MOVES ACROSS THE
AREA THIS WEEKEND...WITH SOME RETURN UPSLOPE FLOW BEHIND IT
PROMOTING LINGERING LIGHT RAIN SHOWERS INTO EARLY SUNDAY NIGHT.
GENERALLY LIGHT RAIN SHOWERS WILL ACCOMPANY THE FRONT AS IT MOVES
PAST.
ANOTHER AREA OF HIGH PRESSURE WILL SETTLE OVER THE REGION MONDAY AND
MONDAY NIGHT...BEFORE ANOTHER AREA OF LOW PRESSURE TAKES SHAPE OVER
THE MIDDLE MISSISSIPPI VALLEY. HOWEVER...IT IS DURING THIS TIME
FRAME THAT THE GFS AND ECMWF MODELS DIVERGE QUITE A BIT...WITH THE
GFS MOVING A LARGE SHIELD OF PRECIPITATION INTO THE AREA BY LATE
TUESDAY MORNING...AND THE ECMWF KEEPING THE AREA DRY FROM MONDAY
NIGHT THROUGH THE END OF THE DAY ON TUESDAY. THE ECWMF COULD BE
UNDERDONE THINGS A LITTLE WITH THE AFOREMENTIONED WEATHER
SYSTEM...SO ADJUSTED THE GRIDS MORE TOWARD THE 12Z RUN OF THE GFS
FOR NOW TO ACCOUNT FOR THIS. THE LATEST VERSION OF THE LONG TERM
ECMWF MOS IS ALSO SHOWING AT LEAST A CHANCE OF RAIN FOR TUESDAY...SO
IT MADE SENSE TO HAVE AT LEAST A CHANCE IN THE FORECAST.
TEMPERATURES WILL CONTINUE TO RUN ABOVE NORMAL THROUGH SUNDAY IN A
SOUTHERLY FLOW REGIME. TEMPERATURES WILL COOL TO NEAR SEASONABLE
LEVELS ON MONDAY AND TUESDAY...AS COOLER AIR SPILLS INTO THE AREA
BEHIND A DEPARTING AREA OF LOW PRESSURE. IN SUMMARY...HIGHS WILL RUN
IN THE LOWER TO MIDDLE 50S FROM THURSDAY THROUGH SUNDAY...BEFORE
COOLING INTO THE MID TO UPPER 40S FROM MONDAY ONWARD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1228 PM EST TUE DEC 11 2012
PESKY MVFR CLOUDS CONTINUE TO HANG AROUND EASTERN KENTUCKY THIS
AFTERNOON. THE 16Z RUC SHOWS THESE CLOUDS HANGING IN THROUGH THE
EVENING AND PERHAPS THROUGH TONIGHT. THUS...HAVE EXTENDED THE CLOUD
COVER IN THE TAFS TO HAVE IT BURN OFF AFTER 13 OR 14Z TOMORROW
MORNING. SOME LOWERING OF THE CIGS CAN BE ANTICIPATED AS THE STRATUS
TRIED TO BUILD DOWNWARDS TONIGHT. CIGS SHOULD BOTTOM OUT AROUND 1500
FEET...BUT COULD GO LOWER IN A FEW AREAS. AFTER TOMORROW
MORNING...VFR CONDITIONS SHOULD BE IN PLACE FOR QUITE SOME TIME TO COME.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM....AR
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1228 PM EST TUE DEC 11 2012
.UPDATE...
ISSUED AT 1228 PM EST TUE DEC 11 2012
A FEW BREAKS IN THE CLOUDS HAVE FINALLY DEVELOPED ACROSS THE FAR
SOUTHWEST AROUND SOMERSET AND MONTICELLO. THIS MAY BE EVIDENCE THAT
THE WEAK UPSLOPE FLOW MAY HAVE A TOUGH TIME HOLDING CLOUDS ACROSS
THIS AREA. MEANWHILE...CLOUDS STILL LOCKED IN PRETTY GOOD ACROSS THE
REMAINDER OF THE AREA. WILL MAKE NECESSARY TWEAKS TO THE SKY COVER.
IF THE SOUTHWEST CLEARS OUT TONIGHT...WE MAY SEE OUR COOLEST READINGS
DOWN THAT WAY TONIGHT...WHILE SLIGHTLY HIGHER LOWS CAN BE EXPECTED
UNDER THE CLOUD COVER. MAY NEED TO TWEAK THE TEMPERATURE GRIDS TO GET
THIS GRADIENT THIS AFTERNOON. NO PLAN TO ISSUE AN UPDATE AT THIS
TIME...BUT WILL RESEND TO THE NDFD.
UPDATE ISSUED AT 905 AM EST TUE DEC 11 2012
NO EVIDENCE THE CLOUDS ARE GOING TO CLEAR OUT ANYTIME IN THE NEXT 6
TO 12 HOURS AS THE LOW CLOUDS EXTEND WELL BACK TO OUR NORTHWEST. THE
DRIZZLE HAS DIMINISHED WITH THE LACK OF RETURNS ON LOCAL RADAR. THE
12Z RUC HAS A GOOD DEAL OF LOW LEVEL MOISTURE IN PLACE THROUGH 00Z
THIS EVENING. WHILE OTHER OPERATIONAL MODELS SHOW NO SUGGESTION OF
THE CLOUDS CONTINUING...OPTING TO KEEP THEM LONGER THAN PREVIOUSLY
ADVERTISED. IN FACT...GOING TO CARRY A GOOD DEAL OF CLOUD COVER
THROUGH TONIGHT. THIS MAY IMPACT LOWS...BUT DECIDED TO FOCUS ON CLOUD
COVER WITH THIS UPDATE. THERE IS STILL SOME UNCERTAINTY IF/WHEN
CLOUDS MAY CLEAR TONIGHT. IF WE CAN CLEAR OUT LATE...LOWS MAY STILL
BE REALIZED. HOWEVER...CLOUDS WOULD OBVIOUSLY KEEP THINGS A BIT
MILDER. FORECAST UPDATE WILL BE OUT SHORTLY.
UPDATE ISSUED AT 650 AM EST TUE DEC 11 2012
CLOUDS ARE HOLDING ON FAR TO THE WEST EARLY THIS MORNING. WITH SUCH
AN EXPANSE UPSTREAM AND WEAK COLD AIR ADVECTION AND UPSLOPE FLOW TO
PERSIST TODAY...HAVE EXTENDED MOSTLY CLOUDY SKIES THROUGH MORE OF THE
DAY TODAY. WEAK RETURNS ON RADAR HAVE BECOME LIGHTER AND SHIFTED
SOUTHEAST...AND PREVIOUS UPDATE FOR TIMING THE END OF
DRIZZLE/FREEZING DRIZZLE THIS MORNING LOOKS ON TRACK.
UPDATE ISSUED AT 501 AM EST TUE DEC 11 2012
DRIZZLE AND FREEZING DRIZZLE WERE OCCURRING OVER PORTIONS OF THE
SOUTHEAST PART OF THE FORECAST AREA EARLY THIS MORNING...AND HAVE
ADDED IT TO THE FORECAST. AS MOISTURE BECOMES MORE SHALLOW...THIS
SHOULD END LATER THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 222 AM EST TUE DEC 11 2012
AFTER A PROLONGED PERIOD OF PRECIP...LOW LEVEL MOISTURE LINGERS
IN COLD AIR ADVECTION AND UPSLOPE FLOW BEHIND A COLD FRONT. THE NAM
USED TO BE FAIRLY REASONABLE IN HANDLING COLD UPSLOPE FLOW IN COLD
SEASONS IN YEARS PAST. HOWEVER...IT SEEMS TO BE BEHAVING DIFFERENTLY
THIS AUTUMN. IT IS HANDLING THE LOW LEVEL MOISTURE VERY POORLY
EARLY THIS MORNING WHEN COMPARED TO REALITY ON SATELLITE
IMAGERY...SIMILAR TO AN EARLIER MOIST UPSLOPE FLOW EVENT THIS AUTUMN.
THE GFS LOOKS MORE REASONABLE IN ITS FORECAST...BUT STILL MAY BE A
BIT TOO FAST TO DRY THINGS OUT. WILL TENTATIVELY LOOK FOR CLOUDS TO
BREAK UP THIS AFTERNOON AS SURFACE RIDGING BUILDS IN...BUT
CONFIDENCE IN TIMING IS NOT HIGH. WITH THAT IN MIND...PREFER THE
COOLER HIGH TEMPS SHOWN IN THE GFS MOS FOR TODAY.
ONLY HIGH AND MAINLY THIN CLOUDS ARE EXPECTED OVERNIGHT TONIGHT. WITH
LIGHT WINDS AND A DRY SURFACE AIR MASS HAVING ARRIVED...WILL LOOK
FOR A MODEST RIDGE/VALLEY TEMPERATURE DIFFERENCE FOR LOWS. THE CLOUDS
AND WEAK COLD AIR ADVECTION SHOULD PRECLUDE A LARGER DIFFERENCE.
SURFACE RIDGING WILL REMAIN IN PLACE FOR WEDNESDAY...WITH SUNSHINE
AND SLIGHT WARMER TEMPERATURES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 222 AM EST TUE DEC 11 2012
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY NIGHT WITH AN
EXITING TROUGH OFF THE EAST COAST. AFTERWORDS...THE UPPER LEVEL
PATTERN BECOMES ZONAL THROUGH THE REST OF THE WORK WEEK. AT THE
SURFACE...STRONG HIGH PRESSURE WILL STAY POSITIONED OVER APPALACHIA
THROUGH THE WEEK AND INTO SATURDAY. BY FRIDAY...AN TROUGH MOVES
ASHORE THE SOUTHWEST COAST AND INTO THE FOUR CORNERS REGION. MODELS
AGREE ON THE WAVE EJECTING INTO THE CENTRAL PLAINS AND EVENTUALLY
INTO THE MS VALLEY BY 12Z TO 18Z SATURDAY. THE TIMING OF THE GFS AND
EURO ON THE ARRIVAL DO DIVERGE A BIT. ONSET OF PRECIP LOOKS TO BE
LATE SATURDAY. AS WELL...THE 00Z SOLUTION OF THE EURO WOULD SUPPORT
THIS MINDSET AS WELL. WILL ADJUST FOR A SLIGHTLY LATER ARRIVAL FROM
THE SOLUTION PROVIDED FROM THE ALL BLEND MODEL. MODEL SOUNDINGS
WOULD SUGGEST THE POSSIBILITY OF THUNDER WITH THE FRONT INTO SUNDAY.
WILL GO WITH SHOWERS FOR NOW AND WAIT TO SEE IF MODELS HAVE A BETTER
HANDLE ON STABILITY.
CONCERNING TEMPERATURES...A ZONAL PATTERN AND LACK OF ANY
SIGNIFICANT CHANGE IN AIR MASS WILL DURING MUCH OF THE EXTENDED WILL
KEEP TEMPS NEAR IF NOT SLIGHTLY ABOVE NORMAL FOR THE FORECAST AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1228 PM EST TUE DEC 11 2012
PESKY MVFR CLOUDS CONTINUE TO HANG AROUND EASTERN KENTUCKY THIS
AFTERNOON. THE 16Z RUC SHOWS THESE CLOUDS HANGING IN THROUGH THE
EVENING AND PERHAPS THROUGH TONIGHT. THUS...HAVE EXTENDED THE CLOUD
COVER IN THE TAFS TO HAVE IT BURN OFF AFTER 13 OR 14Z TOMORROW
MORNING. SOME LOWERING OF THE CIGS CAN BE ANTICIPATED AS THE STRATUS
TRIED TO BUILD DOWNWARDS TONIGHT. CIGS SHOULD BOTTOM OUT AROUND 1500
FEET...BUT COULD GO LOWER IN A FEW AREAS. AFTER TOMORROW
MORNING...VFR CONDITIONS SHOULD BE IN PLACE FOR QUITE SOME TIME TO COME.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...HAL
LONG TERM....SHALLENBERGER
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1221 PM EST TUE DEC 11 2012
...Updated Aviation Discussion...
.Short Term (Today through Wednesday)...
Issued at 300 AM EST Tue Dec 11 2012
In the wake of rapidly exiting low pressure over New England, dry
air has returned to the Lower Ohio Valley. High pressure currently
extends across the southern plains towards the Commonwealth.
Eventually, high pressure will become centered right over Kentucky
by mid-day Wednesday.
Mostly clear, cool, benign weather with light winds will develop
later today and continue through Friday. A stubborn deck of low
clouds will remain in place until after daybreak however. These
strato-cu have not been well forecast by recent mesoscale models,
and persist due to our recent wet weather and quite light winds at
the boundary layer. The RUC is one of the few models that accurately
depict our current strato-cu extending well west across southern
Illinois.
Expect that some clearing will develop across west-central Kentucky
and southwestern Indiana a little bit after dawn. However, the RUC
doesn`t really develop clearing east of Interstate 65 until as late
as noon. To be pessimistic, it is possible that our Bluegrass and
eastern counties may not clear until mid-afternoon or so.
Under light west winds, temperatures will stay cool this afternoon,
with highs ranging from the upper 30s to the lower 40s. For tonight,
expect cold frosty clear conditions with lows falling well down into
the mid 20s. Under clear skies and light winds, Wednesday`s highs
will warm a bit into the mid to upper 40s.
.Long Term (Wednesday Night through Monday)...
Issued at 325 AM EST Tue Dec 11 2012
==============================================
Wednesday Night through Friday Night
Model Preference : Multi-Model Consensus
Forecast Confidence: Medium-High
==============================================
Massive polar vortex looks to stay north of Alaska in the Bering Sea
throughout the upcoming forecast period. This feature combined with
anomalously positive height anomalies across the central Pacific
will lead to a very strong Pacific jet flooding the western US coast
while promoting a deep layer trough to develop. This is not
surprising as the PNA has generally been negative of late and looks
to stay that way through the forecast period according to the
multi-model consensus for which this forecast will lean towards.
With developing trough in the west, downstream ridging is expected
from the Plains and into the eastern US through the period. Small
mid-level wave embedded within the mean flow should be south and
east of our area by Wednesday night. Mid-level heights will rise as
the west coast trough develops, and that combined with surface high
pressure will lead to a dry and quiet weather period through Friday
night. With the upper level ridging building in, we should see a
fairly good moderation in temperatures as the work week ends.
Lows Thursday morning will likely drop into the lower-middle 20s
with possibly some upper teens in the typical colder spots.
However, high temperatures should rebound nicely during the day with
highs reaching the upper 40s across southern Indiana and the
northern half of KY with lower 50s across southern KY. Lows
Thursday night probably will not cool off all that much due to the
increased southerly flow expected. Nonetheless, temperatures should
be near seasonal norms with lows in the upper 20s to around 30.
High temperatures on Friday should be a bit warmer with readings
generally in the 50-55 degree range across southern Indiana and
northern Kentucky. Highs in the mid-upper 50s are likely across
southern Kentucky. Lows Friday night should not be as cold as
clouds will be on the increase ahead of the next weather system.
Probably will see some sort of NE to SW gradient across the area by
late Friday and early Saturday with lows in the lower-mid 30s in the
northeast with upper 30s to around 40 in the central and southwest
sections.
==============================================
Saturday through Tuesday
Model Preference : Euro/Euro Ensembles
Forecast Confidence: Low-Medium
==============================================
Forecast through this period looks rather stormy as a pair of
weather systems will likely affect the region through the period.
The first system is likely to affect the region on Saturday as a
mid-level wave ejects out of the southwestern US and heads northeast
across the Plains and into the Great Lakes. This system will
probably result in another snow storm across the northern plains and
into the western Great Lakes as the low pressure system head
northwest of us. Surface warm front will surge through the region
on Saturday placing us in the warm sector for this storm. Plenty of
clouds and showers will likely accompany the front as it passes
through. As the low slowly heads into the Great Lakes, a surface
cold front will swing through the region sometime on Sunday.
Additional showers and possibly some thunderstorms will be possible
ahead and along the front depending on the instability with the
system. Precipitation will likely push off to the east late Sunday
with cooler, yet seasonal air, pushing back into the region.
After a brief quiet period on Monday, eyes will turn to the next
weather system that is poised to kick out of the southwest US during
the day on Monday. The eventual track of this system is a bit in
question due to the models handling of the developing blocking
pattern across Canada late in the period. While both the GFS and
Euro show the NAO trending negative, each model is very different in
its block configuration. Given the recent 7-day verification of the
Euro and its ensembles over the GFS, have trended the forecast more
toward the Euro at this juncture. With that said, a very strong
closed upper low should eject out of the southern Plains and head
east-northeastward through the Ohio Valley. At the surface, a
strong low pressure system will develop in the lower-Mississippi
Valley and then head north-northeast. The track of the storm looks
to be west of the Ohio Valley, yielding yet another possible snow
storm for the Midwest and western Great Lakes. With the Ohio Valley
remaining on the east side of the system, we`re likely to be warm
sectored again with several round of showers and possible
thunderstorms from Monday night through Tuesday.
Highs Saturday will be above seasonal averages with readings in the
upper middle-upper 50s in the north and upper 50s to around 60 in
the south. Lows Saturday night will cool back into the lower-middle
40s, but only rise slightly on Sunday into the mid-upper 40s. Main
cold push looks to be Sunday night and early Monday with
temperatures falling into the lower-mid 30s. Highs on Monday should
warm back into the lower-middle 40s with overnight lows cooling back
into the middle 30s. Highs on Tuesday look to be in the
middle-upper 40s.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1220 PM EST Tue Dec 11 2012
Main challenge is when the current high-end MVFR ceilings will lift
and/or dissipate. Expect SDF and BWG to scatter out by 19Z and clear
by 20Z, but will take a few hrs longer at LEX. The other fly in the
ointment at LEX is that the ceiling could briefly go VFR before it
scatters out, but either way we are above the fuel-alternate
threshold. The bulk of the clearing in LEX should take place between
20-23Z.
Elongated high pressure will remain parked over the Ohio Valley, so
light west winds this afternoon will go light and variable within
the next few hours, and remain so for the rest of the TAF period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......JSD
Long Term........MJ
Aviation.........RAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
425 PM EST TUE DEC 11 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 424 PM EST TUE DEC 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE CNTRL CONUS. WEAK SHORTWAVES MOVING
THROUGH THIS TROUGH HAVE SUPPORTED AREAS OF VERY LIGHT SNOW AND
FLURRIES TODAY. SOUTHERLY CONVERGENT FLOW OFF LAKE MICHIGAN
SUPPORTED A DOMINANT LAKE EFFECT BAND INTO LUCE COUNTY THIS MORNING
AND EARLY AFTERNOON WHICH DROPPED AT LEAST 7 INCHES OF SNOW NEAR
MCMILLAN. THIS BAND HAS SINCE WEAKENED AND MOVED EAST.
MAIN FCST CONCERN TONIGHT IS POSSIBILITY OF MODERATE LAKE EFFECT
SNOW SHOWERS OVER THE NW CWA.
TONIGHT...THE NW ONTARIO TROUGH WILL MOVE EAST AND DRAG A COLD
FRONT INTO WRN LAKE SUPERIOR. THE COLDER AIR ALONG WITH WINDS
VEERING WRLY WILL PROVIDE FAVORABLE CONDITIONS FOR LES INTO THE
KEWEENAW. WITH 850 MB TEMPS DROPPING TO AROUND -15C...INVERSION
HEIGHTS AOA 7K FT...AND LOW LEVEL CONVERGENCE STRENGTHENING DOWNWIND
FROM THE APOSTLE ISLANDS...A MODERATE TO POSSIBLE HEAVY LES BAND IS
EXPECTED TO DEVELOP. SNOWFALL AMOUNTS OF AT LEAST 2 TO 5 INCHES ARE
POSSIBLE...ESPECIALLY IN THE HIGHER TERRAIN FROM TWIN LAKES TO
CALUMET. SINCE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT A HEAVIER
BAND WILL SET UP OVER THIS AREA...HAVE ELECTED TO GO WITH AN
ADVISORY FOR NORTHERN HOUGHTON COUNTY. THERE IS STILL TOO MUCH
UNCERTAINTY TO INCLUDE KEWEENAW OR ONTONAGON IN AN ADVISORY AT THIS
TIME AS IT LOOKS LIKE THEY MAY BE ON THE FRINGE OF WHERE THE HEAVIER
SNOW BAND WILL SET UP. MODEL SNDGS INDICATE SUBSIDENCE WITH QUICKLY
LOWERING INVERSION HEIGHTS AFTER MIDNIGHT SO EXPECT DIMINISHING LES
INTENSITY BY THAT TIME. COLDEST TEMPS TONIGHT SHOULD BE ALONG THE
WISCONSIN BORDER WHERE SINGLE DIGITS COULD BE REACHED UNDER LIGHT
WINDS AND CLEARING SKIES OF SFC RDG. ELSEWHERE EXPECT LOWS TO BE
GENERALLY IN THE TEENS.
WEDNESDAY...THERE COULD BE SOME LINGERING LES OVER THE KEWEENAW
EARLY IN THE DAY BUT OTHERWISE SUBSIDENCE/DRYING AND LOWERING
INVERSION ALONG WITH QUICKLY BACKING FLOW SHOULD QUICKLY END LES.
SHORTWAVE QUICKLY MOVING ACROSS THE US/CANADIAN BORDER LATE IN THE
DAY MAY BRUSH THE NW PART OF LAKE SUPERIOR WITH LIGHT SNOW/FLURRIES
BUT OTHERWISE FORCING INDICATES BETTER CHC OF SNOW WILL STAY NORTH
AND WEST OF THE CWA. INCREASING H925 WINDS TO 35-45 KTS LATE IN
THE DAY ALONG WITH NEUTRAL TO SLIGHLY UNSTABLE TEMPERATURE PROFILE
FM SFC-H9 AND INCREASING PRESSURE FALLS OVR LK SUPERIOR AND INTO
ONTARIO MAY RESULT IN AREAS NEAR LK SUPERIOR OVR NCNTRL AREAS TO
GUST AOA 30 MPH TOWARD EVENING. EXPECT HIGHS IN THE UPR 20S AND
LOWER 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 424 PM EST TUE DEC 11 2012
JET STREAK WILL BE PUSHING THROUGH THE NEARLY ZONAL NORTHERN FLOW AT
THE START OF THE PERIOD. THE LEFT FRONT OF THIS 110KT STREAK WILL BE
OVER UPPER MICHIGAN AND AIDING A WEAK 1012MB SFC LOW TRACKING ALONG
THE WARM FRONT ON WEDNESDAY NIGHT. FAIRLY DRY SURFACE TO H850 LAYER
OVER MUCH OF THE LAND CWA...SO DON/T THINK THERE WOULD BE MUCH SNOW
HITTING THE SURFACE EVEN WITH THE STRONG WAA ALOFT. THUS...WILL
LIMIT THE EVENING SLIGHT CHANCES TO THE TIP OF THE KEWEENAW
PENINSULA WITH THE CHANCES OVER NORTHERN LAKE SUPERIOR. THIS FORCING
WILL SHIFT EAST DURING THE OVERNIGHT HOURS AND FOLLOW THE LOW INTO
ONTARIO.
BEFORE THE LOW DEPARTS THERE WILL BE STRONG WINDS ALOFT...ESPECIALLY
ABOVE THE INVERSION WHERE H900 WINDS APPROACH 45-50KTS ON WEDNESDAY
EVENING. BUT BELOW THE INVERSION WINDS ARE LIGHTER AND ONLY APPROACH
30-35KTS. AREA OF HIGHER PRESSURE FALLS OVER THE NORTHERN LAKE
INDICATES THE POTENTIAL FOR GUSTY WINDS ON WEDNESDAY EVENING. WITH
IT OCCURRING AT NIGHT...EXPECT THE SUSTAINED WINDS TO BE
HIGHER...BUT THE GUSTS MORE OCCASIONAL AND THE STRONGEST OVER THE
DOWNSLOPE AREAS OF THE NORTH CENTRAL. LOW LEVEL JET DIMINISHES
THROUGH THE NIGHT WITH THE LOW SHIFTING TO THE NORTHEAST AND EXPECT
THE SURFACE WINDS TO FOLLOW SUIT. THESE NIGHT TIME STRONG LOW LEVEL
JET ABOVE AN INVERSION ARE ALWAYS DIFFICULT TO DETERMINE THE AMOUNT
OF WIND THAT WILL MAKE IT TO THE SURFACE. BUFKIT MOMENTUM TRANSFER
IS USUALLY DECENT AT APPROXIMATE SUSTAINED WINDS/GUSTS...AND BOTH
NAM/GFS SOUNDINGS FOR STDM4 AND EAST BUOY ONLY SHOW A 6HR PERIOD
WEDNESDAY EVENING OF 30-35KTS. WILL LEAVE THE GALE WATCH AS
IS...SINCE HIGHER PLATFORMS WILL LIKELY SEE SOME OF THESE WINDS.
AREA WILL BE SOUTH OF THE TRAILING SURFACE TROUGH ON THURSDAY AND
EXPECT AN ABOVE NORMAL DAY OVER UPPER MICHIGAN. REMAINING
SOUTHERLY FLOW AND A FEW BREAKS IN THE MID CLOUDS SHOULD LEAD
TO ALL OF THE AREAS RISING ABOVE FREEZING DURING THE DAY.
MODELS HAVE THE IDEA OF THE TROUGH SAGGING SOUTH OVER SOUTHERN LAKE
SUPERIOR THURSDAY AFTERNOON AND REMAINING IN PLACE INTO FRIDAY
EVENING. THIS IS IN RESPONSE TO A SHORTWAVE THAT STREAKS THROUGH
THE ZONAL FLOW ON THURSDAY. AS THE TROUGH TRIES TO SAG SOUTH...LOW
LEVEL MOISTURE WILL INCREASE ON THE NORTH SIDE OF IT...BUT THERE IS
LITTLE TO NO CONVERGENCE ALONG THE TROUGH TO SUPPORT PRECIPITATION.
THUS...THE MAIN FORCING MECHANISM COMES FROM UPSLOPE FLOW. WITH THIS
SURFACE TROUGH STALLING OVER THE AREA...THE LOW LEVEL FLOW IS VERY
COMPLICATED AND UNCERTAIN AND MAKES PINPOINTING THE LIGHT
PRECIPITATION VERY DIFFICULT. SINCE THE TOP OF THE CLOUDS ARE
AROUND -8C AT 4KFT...DON/T EXPECT THERE TO BE MANY ICE CRYSTALS
IN THE CLOUDS AND REMOVE THE SNOW MENTION AND JUST GO WITH
DRIZZLE OR FREEZING DRIZZLE. LIGHT WESTERLY FLOW WOULD
FAVOR IT TO BE MAINLY OVER THE KEWEENAW ON THURSDAY AFTERNOON.
AFTER THAT...THERE ARE NO STRONG INDICATIONS ON WIND DIRECTIONS AND
WILL KEEP IT HIGHLIGHTED TO THE KEWEENAW FOR MUCH OF THE PERIOD
SINCE THEY WOULD HAVE MORE OPPORTUNITIES WITH THE VARIED WIND
DIRECTIONS. IN ADDITION...PICKED OUT A FEW LOCALIZED AREAS IN THE
NORTH CENTRAL TO HIGHLIGHT A SLIGHT CHANCE OF FREEZING
DRIZZLE BASED ON CONSENSUS WIND DIRECTIONS.
MODELS IN MUCH BETTER AGREEMENT THAN YESTERDAY HEADING INTO THE
WEEKEND...WITH THE GFS SHIFTING TOWARDS THE ECMWF/UKMET/GEM
SOLUTION. BUT...WITH THE INTERACTION OF SEVERAL DIFFERENT WAVES BY
THE TIME IT GETS HERE LEADS TO SOME UNCERTAINTY. THAT BEING
SAID...WITH THE CONSISTENCY OF THE ECMWF OVER THE LAST COUPLE DAYS
AND IT/S SUPERIOR SATELLITE BASED INITIALIZATION...WOULD WANT TO
LEAN TOWARDS THAT IDEA. WITH THE CURRENT TRACK...MUCH OF THE CWA
WILL SEE MEASURABLE...BUT LIGHT SNOW DUE TO THE BROAD AREA OF
CIRCULATION. BEST CHANCES WILL BE OVER THE SOUTHEAST HALF OF THE
CWA AND CLOSER TO THE LOW TRACK AND ALSO OVER NORTH CENTRAL UPPER
MICHIGAN WHERE UPSLOPE FLOW MAY INCREASE AMOUNTS. WITH THE ZONAL
FLOW IN PLACE AHEAD OF THIS WAVE...THERE WON/T BE MUCH COLD AIR TO
WORK WITH AND THAT LIMITS ANY LAKE ENHANCED POTENTIAL DURING THE
SYSTEM AND ALSO ON THE BACKSIDE. 12Z ECMWF HAS COME IN WITH A SLIGHT
SHIFT TO THE NORTH WITH THE LOW...SO FUTURE SHIFTS WILL HAVE TO
MONITOR IF THIS TREND CONTINUES.
FORECAST BECOMES MORE UNCERTAIN FOR MONDAY/TUESDAY OF NEXT
WEEK...WITH THE 00Z ECMWF HOLDING THE UPPER TROUGH OVER THE UPPER
GREAT LAKES REGION AND THE GFS AND IT/S ENSEMBLE PUSHING THE WAVE
OFF TO THE NEW ENGLAND STATES. 12Z ECMWF HAS TRENDED MORE
PROGRESSIVE...SO THERE COULD BE LIGHT LES OFF LAKE SUPERIOR MONDAY
AND TUESDAY AND SLIGHT CHANCE POPS REPRESENTS THAT WELL AT THIS
POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 109 PM EST TUE DEC 11 2012
LOOKING UPSTREAM OVER NRN WI/NRN MN WOULD EXPECT CIGS AT OR SLIGHTLY
ABOVE MVFR MOST OF THE DAY WITH INCREASING SW FLOW AHEAD OF AN
APPROACHING TROUGH. FOLLOWING THE TROF PASSAGE AND WIND SHIFT TO THE
W IN THE EARLY EVNG...EXPECT SHSN TO IMPACT THE EXPOSED KEWEENAW
PENINSULA...WITH IFR OR LIFR CONDITIONS LIKELY AT CMX. DOWNSLOPE
NATURE OF W WIND BEHIND THIS TROF PASSAGE WL LIKELY RESULT IN VFR
CIGS AT SAW BY EARLY EVENING. WINDS BACKING SW AGAIN BY WED MORNING
SHOULD LEAD TO VFR CONDITIONS AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EST TUE DEC 11 2012
SOUTHWEST WINDS TO 25 KTS WILL SHIFT WESTERLY THIS EVENING AS A
TROUGH MOVES THROUGH THE AREA AND THEN DIMINISH BRIEFLY BLO 20 KNOTS
LATE TONIGHT INTO WED MORNING. EXPECT INCREASING SOUTH TO SOUTHWEST
WINDS LATE WEDNESDAY INTO WEDNESDAY NIGHT. MARGINAL GALES TO 35
KNOTS ARE POSSIBLE OVER EASTERN PORTIONS OF LAKE SUPERIOR SO WILL
KEEP GALE WATCH IN EFFECT. A WEAK TROUGH DROPS ACROSS THE LAKE BY
THURSDAY EVENING. WINDS WILL DIMINISH SIGNIFICANTLY THURSDAY NIGHT
INTO FRIDAY IN THE WAKE OF THIS TROUGH. A LOW PRESSURE SYSTEM
DEVELOPING IN THE PLAINS PUSHES INTO WESTERN GREAT LAKES LATE
SATURDAY INTO SUNDAY WHILE HIGH PRESSURE MOVES ACROSS NEW ENGLAND.
WINDS SHOULD INCREASE FROM THE EAST ON SATURDAY OVER LAKE SUPERIOR.
SINCE EXACT TRACK AND DEPTH OF SFC LOW REMAINS UNCERTAIN AT THIS
TIME...WILL KEEP WINDS SUB-GALE FOR NOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ003.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY EVENING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ265>267.
LAKE MICHIGAN...
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LMZ248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
110 PM EST TUE DEC 11 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST TUE DEC 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE CNTRL CONUS. WEAK SHORTWAVE TROUGHS
FROM CNTRL UPPER MI INTO ERN WI AND OVER MN SUPPORTED AREAS OF VERY
LIGHT SNOW AND FLURRIES. ALTHOUGH RADARS SHOWED DECENT COVERAGE WITH
WEAK RETURNS...OBS INDICATED UPSTREAM VISIBILITIES WERE GENERALLY
AOA 6SM. AT THE SFC...SRLY WINDS WERE INCREASING OVER THE REGION
AHEAD OF TROUGH THAT EXTENDED FROM NW ONTARIO INTO MN.
WITH LIGHT WINDS OVER LAKE MICHIGAN AND LAND BREEZES BECOMING MORE
PROMINENT...MID LAKE LES HAD DEVELOPED OFFSHORE FROM NW LOWER MI.
MAIN FCST CONCERNS ARE LAKE EFFECT SNOW TRENDS/AMOUNTS OFF OF LAKE
MICHIGAN TODAY AND INTO THE KEWEENAW TONIGHT.
TODAY...AS THE MOISTURE AND LIGHT PCPN ASSOCIATED WITH THE SHRTWVS
ADVANCE TO THE EAST AND CONVERGENT SRLY FLOW INCREASES ACROSS LAKE
MICHIGAN...MDLS SUGGEST THAT A DOMINANT LES BAND IS LIKELY TO
DEVELOP. THE HIGH RES MODELS CONSENSUS ALSO INDICATE THAT THE BAND WOULD
LIKELY MOVE ONSHORE EAST OF ISQ AND SPREAD QUICKLY TO THE NORTH AND
EAST INTO LUCE COUNTY BY MID MORNING. ALTHOUGH CONFIDENCE IS HIGH
THAT A BAND WILL MOVE INTO EASTERN UPPER MICHIGAN...THERE IS STILL
UNCERTAINTY WITH THE DETAILS OF TIMING/LOCATION OF THE BAND. WITH A
LONG FETCH ACROSS THE LAKE...AND MODERATE INSTABILITY (850 MB TEMP
OF -11C AND LAKE SFC NEAR 6C)...MODERATE TO STRONG CONV...AND
INVERSION HEIGHTS TO AROUND 10K FT...SNOWFALL INTENSITY SHOULD
BECOME HEAVY AT TIMES. EVEN IF 1-2 INCH PER HOUR SNOWFALL RATES
DEVELOP...THE STEADY EASTWARD PROGRESSION SHOULD LIMIT LCL MAX SNOW
AMOUNTS TO AROUND 4 INCHES. SO...AN LES ADVY WAS POSTED FOR SRN
SCHOOLCRAFT AND LUCE COUNTIES.
OTHERWISE...THE BEST CHANCE FOR ADDITIONAL FLURRIES OR LIGHT SNOW
SHOWERS THIS AFTERNOON WILL BE OVER THE WRN CWA AS YET ANOTHER WEAK
SHRTWV MOVES FROM WRN MN MOVES TOWARD THE AREA.
TONIGHT...THE NW ONTARIO TROUGH WILL MOVE TO THE EAST DRAGGING A
COLD FRONT INTO WRN LAKE SUPERIOR. THE COLDER AIR ALONG WITH WINDS
VEERING WRLY WILL PROVIDE FAVORABLE CONDITIONS FOR LES INTO THE
KEWEENAW. WITH 850 MB TEMPS DROPPING TO AROUND -14C...INVERSION
HEIGHTS AROUND 7K FT...AND LOW LEVEL CONVERGENCE STRENGTHENING
DOWNWIND FROM THE APOSTLE ISLANDS...A MODERATE TO HEAVY LES BAND IS
EXPECTED TO DEVELOP. SNOWFALL AMOUNTS OF AT LEAST 2 TO 4 INCHES ARE
LIKELY...ESPECIALLY IN THE HIGHER TERRAIN FROM TWIN LAKES TO CALUMET.
SINCE THERE STILL IS UNCERTAINTY WITH THE DURATION AND LOCATION OF
THE MAIN LES BAND(S)...NO HEADLINE WAS ISSUED AT THIS TIME.
SUBSIDENCE WITH QUICKLY LOWERING INVERSION HEIGHTS AND DIMINISHING
LES INTENSITY IS EXPECTED AFTER MIDNIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM EST TUE DEC 11 2012
AS STRONG H3 JET REFOCUSES OVER EASTERN SEABOARD BY THURSDAY...
EXPECT AMPLIFIED TROUGHING CURRENTLY IN PLACE OVER MUCH OF CONUS
TO TRANSITION TO SPLIT ZONAL FLOW. NORTHERN PLAINS AND UPPER GREAT
LAKES WILL BE AFFECTED BY NORTHERN STREAM THROUGH REST OF THE WORK
WEEK. DISTURBANCES IN THE NORTHERN STREAM NOT FORECAST TO BE ALL
THAT STRONG AND SINCE MAJORITY THE ENERGY FROM STRONGER SHORTWAVES
STAYS MORE OVER CANADA...EXPECT ONLY MINOR IMPACT TO SENSIBLE WX OVR
LAKE SUPERIOR AND UPR MICHIGAN.
A BIT OF LK EFFECT SNOW TO CONTEND WITH OVER THE KEWEENAW TO OPEN
THE LONG TERM PERIOD ON WEDNESDAY MORNING. KEPT 20 POPS IN THROUGH
MID MORNING...BUT THE SUBSIDENCE/DRYING AOA 850MB/LOWERING INVERSION
AND QUICKLY BACKING BLYR FLOW WILL END ANY WHATEVER LK EFFECT
LINGERS PAST 12Z IN SHORT ORDER. ATTN THEN TURNS TO LEAD WAVE
ZIPPING ALONG US/CANADIAN BORDER LATER WEDNESDAY IN INCREASINGLY
ZONAL FLOW. LARGER SCALE DYNAMICS WITH THE WAVE /H7-H5 Q-VECTOR
CONVERGENCE AND LEFT EXIT REGION JET FORCING/ STAYS MOSTLY OVER
ONTARIO WEDNESDAY AFTN AND WEDNESDAY NIGHT. ONLY MODELS THAT GRAZE
NORTHERN CWA /KEWEENAW AND LUCE COUNTY/ WITH QPF ARE THE 00Z
CANADIAN GEM-NH AND UKMET. OTHER MODELS ARE QUITE DRY BLO THE CLOUD
BASE AROUND H7...SO IT TAKES UNTIL PARCELS REACH OVER NORTHERN LK
SUPERIOR/NORTHERN ONTARIO TO SATURATE/PRECIPITATE. DID NOT WANT TO
COMPLETELY IGNORE GEM-NH AND UKMET...BUT KEPT POPS IN THE FAR NORTH
NO MORE THAN 20 PCT. BEGINNING TO THINK THAT INSTEAD OF PRECIP THAT
GUSTY SW WINDS AND STEADY TEMPS IN THE UPR 20S TO MID 30S MAY BE
MAIN PRIMARY RESULT FROM THIS INITIAL WAVE. H925-H85 WINDS 35-45 KTS
ALONG WITH NEUTRAL TO SLIGHLY UNSTABLE TEMPERATURE PROFILE SFC-H9
ALONG WITH PRESSURE FALLS OVR LK SUPERIOR AND INTO ONTARIO MAY
RESULT IN AREAS NEAR LK SUPERIOR OVR NCNTRL UPR MICHIGAN...NEAR LK
MICHIGAN AND OVER MUCH OF EASTERN CWA GUSTING SEEING WINDS GUSTING
20-35 MPH THROUGH THE NIGHT WITH MINIMAL TEMP FALL. WENT WITH
NON-DIURNAL TEMP TREND TO COVER THIS POSSIBILITY.
LEAD WAVE HEADS TOWARD QUEBEC BY DAYBREAK THURSDAY AS SFC TROUGH
EASES ACROSS LK SUPERIOR/NORTHERN UPR MICHIGAN. ANOTHER WAVE IS
LURKING UPSTREAM IN THE QUICK ZONAL FLOW ALOFT. UKMET/GEM-NH
STRONGEST WITH WAVE...GFS/ECMWF NOT SO MUCH. SINCE THE LOW-LEVEL
TROUGH BECOMES PARALLEL WITH UPPER FLOW...NOT TOO KEEN ON PUSHING
TROUGH AS FAR SOUTH AS GEM-NH HAS IT BY THURSDAY AFTN. INSTEAD KEPT
BOUNDARY HUNG UP OVR KEWEENAW WITH JUST A SMALL CHANCE OF SNOW
SHOWERS BY AFTN AS SHALLOW COLD AIR TRIES TO SETTLE BACK ACROSS
NORTHERN CWA. TEMPS AHEAD OF FRONT...WHEREVER IT ENDS UP...COULD
GET FAIRLY WARM WITH READINGS WELL INTO THE 30S...ESPECIALLY EAST.
FOR THURSDAY NIGHT INTO FRIDAY...MAY BE SETTING UP FOR ANOTHER
DZ/FZDZ OR SNOW SCENARIO. GFS IS COLDER...BUT GFS/ECMWF/GEM-NHEM
INDICATE H85 TEMPS BORDERLINE TO GET ICE NUCLEATION/SNOW. ALSO GFS
AND ECMWF INDICATE A LOT OF LOW-LEVEL MOISTURE BUT NOT AS MUCH H85
MOISTURE. INTRODUCED SOME DZ/FZDZ FOR FRIDAY AND FRIDAY NIGHT
BETWEEN THE TROUGH THAT DROPS THROUGH LATE THURSDAY AND OUT AHEAD
OF STRONGER LOW PRESSURE SYSTEM MOVING INTO REGION NEXT WEEKEND.
UPSLOPE NE THEN SE WINDS WOULD ONLY HELP OUT THE DZ/FZDZ.
AS FLOW BECOMES SPLIT LATE THIS WEEK...STRONG SOUTHERN STREAM WAVE
TAKES SHAPE OVER DESERT SOUTHWEST. IT IS THIS WAVE THAT BECOMES MAIN
INSTIGATOR FOR LEE ROCKIES CYCLOGENESIS LATE FRIDAY INTO SATURDAY.
THIS SOUTHERN STREAM WAVE/ASSOCIATED SFC LOW ARE FORECAST TO EJECT
OUT OF SOUTHERN PLAINS INTO WESTERN GREAT LAKES OR OHIO VALLEY TO
END THE WEEKEND. FLOW PATTERN BECOMES QUITE MESSY THOUGH AS ANOTHER
WAVE WILL BE QUICKLY FOLLOWING INTO SOUTHERN PLAINS AND THERE IS
EVEN A WAVE IN THE NORTHERN STREAM THAT WILL TRY TO MAKE A RUN INTO
THE NORTHERN PLAINS...THOUGH IT DOES SEEM AT LEAST AT THIS POINT...
THAT THAT WAVE MAY GET DEFLECTED OFF INTO CANADA AWAY FROM THE FRAY.
ALL THE WAVES PROBABLY WILL END UP INTERACTING WITH EACH OTHER IN
SOME FORM OR ANOTHER. NET RESULT IS A NOT SO CLEAR CUT FORECAST OF
THE SFC LOW/THERMAL PROFILE/PRECIPITATION COVERAGE AND INTENSITY
ACROSS UPPER LAKES REGION LATER SATURDAY INTO SUNDAY. ONLY REAL
MODEL TREND OF NOTE IS GFS HAS TRENDED TOWARD ECMWF IDEA OF A MORE
CLOSED OFF SOUTHERN STREAM/SFC LOW SINCE THE 18Z RUN ON MONDAY AFTN.
TROUBLE IS THAT THIS WAVE IS STILL OVER GULF OF ALASKA THIS MORNING
AND REALLY WILL NOT BE ONSHORE OVER CONUS FOR BETTER ROAB SAMPLING
UNTIL LIKELY FRIDAY MORNING AT THE EARLIEST. EXPECT UNCERTAINTY TO
CLOUD THE FORECAST UNTIL THAT POINT WITH THE SPECIFICS OF THE TRACK
OF SFC LOW. A CONSENSUS WAS RETAINED FOR POPS NOW. FOR OVERALL PTYPE
LEANED ON LARGE SCALE THICKNESSES...THOUGH WHERE FLOW WAS ONSHORE
OFF THE GREAT LAKES...KEPT SOME MENTION OF RAIN AS WELL WITH TEMPS
EXPECTED TO BE IN THE MID 30S. LINGERED CHANCE POPS FOR MAINLY SNOW
OVER THE EAST ON SUNDAY. NOT A LOT OF COLD AIR FCST TO BE AROUND IN
WAKE OF THE MAINLY SOUTHERN STREAM ORIGIN SYSTEM...SO KEPT POPS FOR
ANY LK EFFECT INTO MONDAY ON THE LOW SIDE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 109 PM EST TUE DEC 11 2012
LOOKING UPSTREAM OVER NRN WI/NRN MN WOULD EXPECT CIGS AT OR SLIGHTLY
ABOVE MVFR MOST OF THE DAY WITH INCREASING SW FLOW AHEAD OF AN
APPROACHING TROUGH. FOLLOWING THE TROF PASSAGE AND WIND SHIFT TO THE
W IN THE EARLY EVNG...EXPECT SHSN TO IMPACT THE EXPOSED KEWEENAW
PENINSULA...WITH IFR OR LIFR CONDITIONS LIKELY AT CMX. DOWNSLOPE
NATURE OF W WIND BEHIND THIS TROF PASSAGE WL LIKELY RESULT IN VFR
CIGS AT SAW BY EARLY EVENING. WINDS BACKING SW AGAIN BY WED MORNING
SHOULD LEAD TO VFR CONDITIONS AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST TUE DEC 11 2012
WINDS 25 KTS OR BLO THROUGH MIDDAY WEDNESDAY THEN EXPECT INCREASING
SOUTH TO SOUTHWEST WINDS LATE WEDNESDAY/WEDNESDAY NIGHT AND INTO
EARLY THURSDAY MORNING. GALES LIKELY OVER EASTERN PORTIONS OF LAKE
SUPERIOR SO HAVE ISSUED GALE WATCH. TROUGH DROPS ACROSS THE LAKE BY
THURSDAY EVENING. WINDS WILL DIMINISH SIGNIFICANTLY THURSDAY NIGHT
INTO FRIDAY IN WAKE OF THIS TROUGH. LOW PRESSURE SYSTEM DEVELOPING
IN THE PLAINS PUSHES INTO WESTERN GREAT LAKES LATE SATURDAY INTO
SUNDAY WHILE HIGH PRESSURE MOVES ACROSS NEW ENGLAND. WINDS SHOULD
INCREASE FROM THE EAST ON SATURDAY OVER LAKE SUPERIOR. EXACT TRACK
AND DEPTH OF SFC LOW REMAINS UNCERTAIN THOUGH...SO DID NOT GO STRONG
ON WINDS AT THIS TIME. POSSIBLE THAT WINDS MAY EVENTUALLY NEED TO BE
INCREASED COMPARED TO WHAT IS IN THE CURRENT FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MIZ007.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY EVENING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ265>267.
LAKE MICHIGAN...
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LMZ248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1253 PM EST TUE DEC 11 2012
.AVIATION...
//DISCUSSION...
DAYTIME HEATING AND MOISTURE FROM FLOW OFF LAKE MICHIGAN ARE BEING
AIDED BY A WEAK UPPER LEVEL DISTURBANCE PASSING THROUGH THE
AREA...AND ARE ALLOWING FOR THE DEVELOPMENT OF AN MVFR STRATOCU
DECK. THIS DECK SHOULD BREAK IN THE EARLY EVENING AS THE WAVE
PASSES...AND AS WE LOSE DIURNAL INFLUENCES.
FLOW WILL TURN MORE WESTERLY OFF THE GREAT LAKES TONIGHT...BECOMING
MORE FAVORABLE FOR LAKE EFFECT CLOUDS TO STREAM INLAND ONCE AGAIN.
EXPECT MVFR TO LOW VFR CEILING TO FILL IN LATE...STARTING AT MBS AND
WORKING SOUTH BEFORE DAYBREAK. THIS DECK SHOULD THEN MIX BACK OUT
EARLY WEDNESDAY AFTERNOON AS FLOW TURNS MORE SOUTHERLY.
FOR DTW... BKN CEILINGS BETWEEN 2500 AND 3000 FEET WILL PREVAIL
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY EVENING
(UNTIL ABOUT 22-23Z)...BEFORE DAYTIME HEATING CEASES AND THE DECK IS
ALLOWED TO BREAK UP. MOSTLY CLEAR CONDITIONS WILL THEN LAST UNTIL
CLOSE TO SUNRISE WEDNESDAY WHEN PATCHES OF VFR STRATOCU BELOW 5000
FEET WILL AGAIN BE POSSIBLE FROM AS LAKE EFFECT CLOUDS DEVELOP FROM
OFF LAKE MICHIGAN.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE IN TIMING AND COVERAGE OF CEILING BELOW 5000
TODAY AND LATE TONIGHT.
&&
.PREV DISCUSSION...ISSUED 349 AM EST TUE DEC 11 2012
SHORT TERM... TODAY AND TONIGHT
COMPLEXITIES IN THE FORECAST FOR TODAY INCLUDE EVOLUTION OF LAKE
EFFECT SNOW NEAR THE LAKE HURON SHORELINE DURING THE MORNING ALONG
WITH INLAND CLOUD COVERAGE THROUGHOUT THE DAY.
EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR IN EXETER
INDICATE A BAND OF LAKE EFFECT SNOW PERCOLATING OVER THE SOUTH HALF
OF LAKE HURON WITHIN THE INCREASINGLY CONVERGENT LAKE INDUCED
SURFACE TROUGH. MODEL DEPICTIONS OF 850 MB TEMPERATURE SUGGEST
INSTABILITY IS ALREADY MORE THAN ADEQUATE WITH DELTA-T AVERAGING 18C
OVER THE SOUTH HALF OF THE LAKE. THE SOMEWHAT MUTED CONVECTION
DURING THE EARLY MORNING IS LIKELY A RESULT OF MID LEVEL SUBSIDENCE
INDICATED IN WATER VAPOR IMAGERY ON THE HEELS OF THE SHEAR AXIS
DEPARTING TO THE EAST. THIS IS EXPECTED TO CHANGE AS A SMALL BUT
SUFFICIENTLY STRONG SHORT WAVE SLIDES THROUGH LOWER MICHIGAN TOWARD
SUNRISE. THIS FEATURE HELPED SUPPORT A STRONG LAKE EFFECT BAND OVER
SOUTHERN LAKE MICHIGAN DURING THE NIGHT WITH CONVECTION DEEP ENOUGH
FOR SNOW SHOWERS TO REACH NORTHWEST OHIO. AS THE WAVE MOVES TOWARD
LAKE HURON DURING THE REST OF THE MORNING, IT IS EXPECTED TO BOOST
THE CIRCULATION WITHIN THE LAKE TROUGH AND HELP FLARE UP LAKE EFFECT
SNOW THERE AS WELL BEFORE QUICKLY SLIDING EASTWARD BY LATE MORNING.
AS THE WAVE APPROACHES, IT IS EXPECTED TO DRAW THE LAKE TROUGH
TOWARD THE SHORELINE OF THE THUMB FOR A FEW HOURS AROUND SUNRISE
BEFORE THE PASSAGE OF THE LARGE SCALE SURFACE RIDGE BACKS THE LOW
LEVEL FLOW TOWARD THE SOUTHWEST. MODIFIED RAP MODEL SOUNDINGS
INDICATE LAKE INDUCED CAPE APPROACHING 500 J/KG AND EQUILIBRIUM
LEVEL PUSHING 10 KFT BY 12Z, INGREDIENTS FOR HEAVY LAKE EFFECT SNOW
SHOWERS, BUT A LATE START AND SHORT DURATION WILL BE THE LIMITING
FACTORS IN SUPPORT OF A 1 TO 2 INCH FORECAST.
ELSEWHERE AROUND SE MICHIGAN, THE NORTHERLY LOW LEVEL FLOW HAS
BECOME JUST NEUTRAL ENOUGH TO ALLOW FOR SOME BREAKS IN THE STRATUS
DURING THE EARLY MORNING. EXPECT THIS WILL CONTINUE THROUGH LATE
MORNING BUT IN A RANDOM FASHION THAT WILL PROVIDE INTERVALS OF
PARTLY SUNNY CONDITIONS THROUGH CENTRAL PORTIONS OF LOWER MICHIGAN.
THE BACKING LOW LEVEL FLOW WILL THEN DIRECT CLOUDS, AND PERHAPS EVEN
A FEW SNOW SHOWERS, EASTWARD FROM LAKE MICHIGAN AS PART OF A LARGER
AREA OF STRATUS COVERING THE WESTERN GREAT LAKES. THE EXTRA CLOUD
COVER COMBINED WITH LATE DEVELOPING SOUTHWEST SURFACE WIND WILL
CONFINE MAX TEMPS TO THE LOWER AND MID 30S TODAY. THE SOUTHWEST FLOW
WILL CARRY IN DRY AIR FROM THE MID MISSISSIPPI VALLEY BY TONIGHT
WHICH WILL SCOUR OUT THE LOW CLOUDS BUT NOT RESULT IN MUCH WARMING.
THE INCREASED GRADIENT FLOW WILL BATTLE THE TENDENCY FOR SURFACE
WIND DECOUPLING AND RESULTANT RADIATIONAL COOLING FOR LOWS DROPPING
BACK INTO THE LOWER TO MID 20S.
LONG TERM...WEDNESDAY THROUGH MONDAY
VERY LITTLE TO DISCUSS IN THE WEDNESDAY TO FRIDAY TIMEFRAME. THE MAIN
TROUGH AXIS WILL BE OVER LOWER MICHIGAN AT THE START OF THE
PERIOD...WHICH WILL GIVE WAY TO A GENERAL RISING OF GEOPOTENTIAL
HEIGHTS THROUGH THE END OF THE WORK WEEK. SPLIT FLOW IS STILL
FORECASTED TO DEVELOP WITH THE POLAR JET AXIS REMAINING NORTH OF
LAKES SUPERIOR/HURON ALONG WITH THE PERSISTENCE OF A VERY NOTEWORTHY
SOUTHERN STREAM AXIS. GUIDANCE CAME IN MARKEDLY WARMER FOR WEDNESDAY
AND BOOSTED TEMPERATURES UPWARDS A COUPLE OF DEGREES. DAYTIME HIGHS
ARE EXPECTED TO REACH/CLIMB ABOVE 40 DEGREES FOR BOTH THURSDAY AND
FRIDAY.
A TON OF UNCERTAINTY EXISTS WITH REGARDS TO HOW THIS WEEKEND WILL
PLAY OUT. THE PERTINENT WEATHER ASPECTS WILL COME DOWN TO THE
DETAILS. UNFORTUNATELY...THE MODEL DATA SUGGESTS THAT IT WILL TAKE
UNTIL FRIDAY MORNING BEFORE THE MAIN TROUGH AXIS OF THE IMPORTANT
SHORTWAVE WILL COME ONSHORE OF SOUTHERN CA/BAJA OF MEXICO. THAT IS A
LONG TIME TO WAIT. LATEST TRENDING FOR THE 11.00Z SUITE WAS THAT THE
ECMWF ARRIVED IN MORE AGREEMENT WITH THE GFS SOLUTION. THE GFS HAS
BEEN ADVERTISING THE FIRST DEVELOPED SYSTEM (ARRIVING OVER THE GREAT
LAKES ON SATURDAY) WILL RUN INTO A EASTERN CANADIAN/GREENLAND
BLOCKING RIDGE. THE MODELS SUGGEST THAT WHAT BEGINS AS RATHER CRISP
BAROCLINIC DYNAMICS TURNS MUSHY IN AS LITTLE AS 12 HOURS. THE HIGHER
CONFIDENCE PORTION OF THIS FORECAST IS THE HIGH AMOUNT OF MOISTURE
IN TOW WITH THE SYSTEM. THE LIKELIHOOD OF WIDESPREAD PRECIPITATION
IS HIGH AND WENT AHEAD AND HIKED POPS INTO THE HIGH LIKELY RANGE FOR
SATURDAY AND SATURDAY NIGHT. THE ECMWF BRINGS THE MAIN UPPER LEVEL
PV ANOMALY NORTH OF THE SOO...WHICH SUGGESTS THAT PRECIPITATION TYPE
WILL BE ON THE WARM END OF THE SPECTRUM. THE GFS REMAINS A LITTLE
FARTHER SOUTH WITH THE PV ANOMALY...OVER LOWER MICHIGAN AND IS JUST
ONE OF MANY POINTS OF CONTENTION AMONGST THE SUITE.
MARINE...
WEAK HIGH PRESSURE WILL MOVE QUICKLY THROUGH LAKE HURON AND LOWER
MICHIGAN DURING THE AFTERNOON IN A FAVOR OF THE NEXT LOW PRESSURE
SYSTEM MOVING THROUGH NORTHERN ONTARIO. INCREASING SOUTHWEST WIND
WILL REACH GUSTS TO 30 KNOTS TONIGHT OVER THE OPEN WATERS OF CENTRAL
AND NORTHERN LAKE HURON. THE WIND WILL NOT BE QUITE AS STRONG OVER
SAGINAW BAY BUT STRONG ENOUGH TO BUILD WAVES OVER 4 FEET TONIGHT
THROUGH WEDNESDAY REQUIRING A SMALL CRAFT ADVISORY THERE. A LARGER
SYSTEM IS THEN EXPECTED TO TRACK THROUGH NORTHERN ONTARIO AS WELL
DURING WEDNESDAY NIGHT INTO THURSDAY THAT WILL MAINTAIN SOUTHWEST
WIND OVER THE LAKES AND BRING WARMER AIR OVER THE WATER. THE
INCREASED STABILITY BY THIS TIME WILL LIMIT GUST POTENTIAL TO 30
KNOTS OR LESS THROUGH THURSDAY BEFORE THE TRAILING COLD FRONT
SETTLES OVER THE REGION BY FRIDAY. THE FRONT WILL STALL OVER THE
CENTRAL LAKES AS A STRONG LOW PRESSURE SYSTEM TAKES SHAPE OVER THE
PLAINS STATES AND MOVES INTO THE GREAT LAKES DURING THE WEEKEND.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM TUESDAY TO 4 PM
WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....HLO
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
314 PM CST TUE DEC 11 2012
.SHORT TERM...THROUGH WEDNESDAY NIGHT.
LAKE EFFECT SNOW ALONG THE NORTH SHORE HAS DIMINISHED THIS
AFTERNOON AS WINDS HAVE TURNED MORE WESTERLY BEHIND THE DEPARTING
LOW. A LAKE BAND OF LIGHT SNOW SHOWERS ALSO EXTENDED FROM JUST OFF
SHORE OF DOUGLAS COUNTY...ALONG THE BAYFIELD PENINSULA TOWARD RED
CLIFF. THIS WILL LIKELY CONTINUE THROUGH MOST OF THE EVENING AS
THE LOW LEVEL FLOW REMAINS WEST-SOUTHWEST. FETCH WILL BE
LIMITED...AND THE NAM AND RUC BOTH SHOW LOWERING RH THROUGH THE
EVENING...SO WE THINK ACCUMULATIONS WILL BE LIMITED. PLENTY OF CLOUDS
REMAIN OVER THE REST OF THE NORTHLAND...WITH FLURRIES/LIGHT SNOW
STILL OCCURRING. A WEAK SHORTWAVE WAS MOVING THROUGH CENTRAL
MINNESOTA THIS AFTERNOON...WITH RADAR HIGHER RETURNS WELL SOUTH OF
THE CWA.
HIGH PRESSURE WILL MOVE QUICKLY THROUGH THE NORTHLAND
TONIGHT...WITH WAA INCREASING OVERNIGHT AHEAD OF AN AREA OF LOW
PRESSURE. WE HAVE A CHANCE FOR LIGHT SNOW LATER TONIGHT OVER
NORTHWEST AREAS...AND INCREASED POPS TO LIKELY BETWEEN 09-12Z OVER
KOOCHICHING COUNTY. THE WAA AND WEAK SHORT WAVE WILL CONTINUE TO
IMPACT FAR NORTHERN AREAS WEDNESDAY...AND WE HAVE INCREASED POPS
TO LIKELY AS ACCUMULATIONS UP TO TWO INCHES WILL BE POSSIBLE IN
SPOTS. THERE MAY ALSO BE A NARROW WINDOW FOR LAKE EFFECT SNOW
WEDNESDAY MORNING BETWEEN LITTLE MARAIS AND GRAND PORTAGE AGAIN.
FETCH BECOMES FAVORABLE WEDNESDAY MORNING...BUT WAA WILL CAUSE
850MB TEMPS TO RISE QUICKLY. WE`LL HAVE TO KEEP A CLOSE EYE ON
THAT AREA AS WE COULD GET A QUICK BURST OF SEVERAL INCHES OF SNOW
IF THE TEMPS ALOFT DON`T WARM AS FAST AS ANTICIPATED.
TEMPERATURES TONIGHT WILL BE A CHALLENGE...AS THEY WILL BE HIGHLY
DEPENDENT ON CLEARING. WE DID DROP THEM MOST AREAS...HAVE SOME
WELL BELOW ZERO OVER NORTHEAST MINNESOTA. EVENING SHIFT WILL HAVE
TO MONITOR CLOUD TRENDS CLOSELY...AS WE MAY NOT BE COLD ENOUGH IF
IT CLEARS LONGER THAN ANTICIPATED. HIGHS WEDNESDAY WILL BE WARMER
THAN TODAY...WITH SOME AREAS REACHING AROUND THIRTY OVER NORTHWEST
WISCONSIN.
CONFIDENCE WEDNESDAY NIGHT IS LOWER THAN AVERAGE REGARDING SNOW
POTENTIAL. NAM WAS SHOWING A WEAK CIRCULATION AT 850MB AND
FORECASTS SOME LIGHT SNOW OVER THE FAR NORTH. THE MODELS ARE NOT
IN VERY GOOD AGREEMENT DURING THIS PERIOD. WE KEPT A MENTION OF
LIGHT SNOW OVER THE NORTH...AND EXPANDED A BIT SOUTH OVER OUR
WESTERN COUNTIES. IF THE MODELS TREND TOWARD THE NAM...WE WILL
NEED HIGHER POPS FOR SOME LIGHT SNOW ACCUMULATIONS OVER THE WEST
AND NORTHERN CWA.
.LONG TERM...THURSDAY - MONDAY.
THE NORTHLAND SHOULD FIND ITSELF THURSDAY MORNING WITH A STATIONARY
FRONT NEAR OR SOUTH OF THE FA. THERE MAY BE SOME LIGHT SNOW ACROSS
THE NORTHERN FA THURSDAY ASSOCIATED WITH PLENTIFUL LOW CLOUDS NORTH
OF THE FRONT. HIGH PRESSURE IN CANADA WILL BEGIN TO EXERT GREATER
INFLUENCE ON THE NORTHLAND THURSDAY NIGHT...PROVIDING DRY WEATHER
THROUGH FRIDAY NIGHT. THE MODELS ARE LATCHING ONTO A STRONG LOW
PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS TO UPPER MIDWEST ON
SATURDAY. THIS SYSTEM COULD BRING SIGNIFICANT SNOWFALL TO PARTS OF
THE FA...ESPECIALLY THE SOUTHEASTERN FA WHICH WILL BE IN BETTER
PROXIMITY TO THE SYSTEM. TEMPERATURES THROUGH THE PERIOD SHOULD BE
NEAR OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...18Z TAFS
IFR/MVFR CONDITIONS ACROSS NE MINNESOTA AND NW MINNESOTA ARE
EXPECTED TO CONTINUE THROUGH THIS AFTERNOON AND INTO EARLY THIS
EVENING. CIGS WILL LIKELY RANGE FROM 1500 TO 3000 FT...AND THE
-SN WILL OCCASIONALLY REDUCE VIS TO IFR. THE SNOW SHOULD BEGIN TO
SUBSIDE LATER THIS AFTERNOON. THE CLOUDS WILL BEGIN TO CLEAR AT
KINL BY MID AFTERNOON...AND THEN AT OTHER TERMINALS LATE THIS
AFTERNOON AND EARLY THIS EVENING. EXPECT THE 5 TO 10 KNOT W TO SW
WINDS TO BECOME S TO SE TONIGHT. KINL COULD SEE MVFR CIGS
REDEVELOP LATE TONIGHT AND TOMORROW MORNING...BUT VFR CONDITIONS
ARE LIKELY TO RETURN TO KDLH/KHIB/KBRD/KHYR TONIGHT.
&&
.POINT TEMPS/POPS...
DLH 3 28 20 29 / 10 10 10 20
INL -9 23 8 19 / 60 70 30 20
BRD -5 29 17 28 / 10 10 20 10
HYR 2 32 22 33 / 20 10 10 0
ASX 5 33 25 35 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ140.
&&
$$
SHORT TERM...MELDE
LONG TERM....GROCHOCINSKI
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS DULUTH MN
306 PM CST TUE DEC 11 2012
.SHORT TERM...THROUGH WEDNESDAY NIGHT.
LAKE EFFECT SNOW ALONG THE NORTH SHORE HAS DIMINISHED THIS
AFTERNOON AS WINDS HAVE TURNED MORE WESTERLY BEHIND THE DEPARTING
LOW. A LAKE BAND OF LIGHT SNOW SHOWERS ALSO EXTENDED FROM JUST OFF
SHORE OF DOUGLAS COUNTY...ALONG THE BAYFIELD PENINSULA TOWARD RED
CLIFF. THIS WILL LIKELY CONTINUE THROUGH MOST OF THE EVENING AS
THE LOW LEVEL FLOW REMAINS WEST-SOUTHWEST. FETCH WILL BE
LIMITED...AND THE NAM AND RUC BOTH SHOW LOWERING RH THROUGH THE
EVENING...SO WE THINK ACCUMULATIONS WILL BE LIMITED. PLENTY OF CLOUDS
REMAIN OVER THE REST OF THE NORTHLAND...WITH FLURRIES/LIGHT SNOW
STILL OCCURRING. A WEAK SHORTWAVE WAS MOVING THROUGH CENTRAL
MINNESOTA THIS AFTERNOON...WITH RADAR HIGHER RETURNS WELL SOUTH OF
THE CWA.
HIGH PRESSURE WILL MOVE QUICKLY THROUGH THE NORTHLAND
TONIGHT...WITH WAA INCREASING OVERNIGHT AHEAD OF AN AREA OF LOW
PRESSURE. WE HAVE A CHANCE FOR LIGHT SNOW LATER TONIGHT OVER
NORTHWEST AREAS...AND INCREASED POPS TO LIKELY BETWEEN 09-12Z OVER
KOOCHICHING COUNTY. THE WAA AND WEAK SHORT WAVE WILL CONTINUE TO
IMPACT FAR NORTHERN AREAS WEDNESDAY...AND WE HAVE INCREASED POPS
TO LIKELY AS ACCUMULATIONS UP TO TWO INCHES WILL BE POSSIBLE IN
SPOTS. TEMPERATURES TONIGHT WILL BE A CHALLENGE...AS THEY WILL BE
HIGHLY DEPENDENT ON CLEARING. WE DID DROP THEM MOST AREAS...HAVE
SOME WELL BELOW ZERO OVER NORTHEAST MINNESOTA. EVENING SHIFT WILL
HAVE TO MONITOR CLOUD TRENDS CLOSELY...AS WE MAY NOT BE COLD
ENOUGH IF IT CLEARS LONGER THAN ANTICIPATED. HIGHS WEDNESDAY
WILL BE WARMER THAN TODAY...WITH SOME AREAS REACHING AROUND THIRTY
OVER NORTHWEST WISCONSIN.
CONFIDENCE WEDNESDAY NIGHT IS LOWER THAN AVERAGE REGARDING SNOW
POTENTIAL. NAM WAS SHOWING A WEAK CIRCULATION AT 850MB AND
FORECASTS SOME LIGHT SNOW OVER THE FAR NORTH. THE MODELS ARE NOT
IN VERY GOOD AGREEMENT DURING THIS PERIOD. WE KEPT A MENTION OF
LIGHT SNOW OVER THE NORTH...AND EXPANDED A BIT SOUTH OVER OUR
WESTERN COUNTIES. IF THE MODELS TREND TOWARD THE NAM...WE WILL
NEED HIGHER POPS FOR SOME LIGHT SNOW ACCUMULATIONS OVER THE WEST
AND NORTHERN CWA.
.LONG TERM...THURSDAY - MONDAY.
THE NORTHLAND SHOULD FIND ITSELF THURSDAY MORNING WITH A STATIONARY
FRONT NEAR OR SOUTH OF THE FA. THERE MAY BE SOME LIGHT SNOW ACROSS
THE NORTHERN FA THURSDAY ASSOCIATED WITH PLENTIFUL LOW CLOUDS NORTH
OF THE FRONT. HIGH PRESSURE IN CANADA WILL BEGIN TO EXERT GREATER
INFLUENCE ON THE NORTHLAND THURSDAY NIGHT...PROVIDING DRY WEATHER
THROUGH FRIDAY NIGHT. THE MODELS ARE LATCHING ONTO A STRONG LOW
PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS TO UPPER MIDWEST ON
SATURDAY. THIS SYSTEM COULD BRING SIGNIFICANT SNOWFALL TO PARTS OF
THE FA...ESPECIALLY THE SOUTHEASTERN FA WHICH WILL BE IN BETTER
PROXIMITY TO THE SYSTEM. TEMPERATURES THROUGH THE PERIOD SHOULD BE
NEAR OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...18Z TAFS
IFR/MVFR CONDITIONS ACROSS NE MINNESOTA AND NW MINNESOTA ARE
EXPECTED TO CONTINUE THROUGH THIS AFTERNOON AND INTO EARLY THIS
EVENING. CIGS WILL LIKELY RANGE FROM 1500 TO 3000 FT...AND THE
-SN WILL OCCASIONALLY REDUCE VIS TO IFR. THE SNOW SHOULD BEGIN TO
SUBSIDE LATER THIS AFTERNOON. THE CLOUDS WILL BEGIN TO CLEAR AT
KINL BY MID AFTERNOON...AND THEN AT OTHER TERMINALS LATE THIS
AFTERNOON AND EARLY THIS EVENING. EXPECT THE 5 TO 10 KNOT W TO SW
WINDS TO BECOME S TO SE TONIGHT. KINL COULD SEE MVFR CIGS
REDEVELOP LATE TONIGHT AND TOMORROW MORNING...BUT VFR CONDITIONS
ARE LIKELY TO RETURN TO KDLH/KHIB/KBRD/KHYR TONIGHT.
&&
.POINT TEMPS/POPS...
DLH 3 28 20 29 / 10 10 10 20
INL -9 23 8 19 / 60 70 30 20
BRD -5 29 17 28 / 10 10 20 10
HYR 2 32 22 33 / 20 10 10 0
ASX 5 33 25 35 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ140.
&&
$$
SHORT TERM...MELDE
LONG TERM....GROCHOCINSKI
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1250 PM EST TUE DEC 11 2012
.SYNOPSIS...
A WESTERLY FLOW OF SEASONABLY COLD AIR WILL PREVAIL THROUGH MID-
WEEK...ALONG WITH MAINLY DRY WEATHER...AS HIGH PRESSURE GRADUALLY
BUILDS INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
953 AM UPDATE...
STRONG COLD AIR ADVECTION CONTINUES THIS MORNING. LOW LEVEL DRY
AIR AND SHEAR IS WORKING TO UNDERMINE ATTEMPTS AT LES OFF OF
ONTARIO, SO CONTINUE TO EXPECT LITTLE IN THE WAY OF SNOW
ACCUMULATION.
TEMPS WON`T RISE MORE THAN A FEW DEGREES FROM CURRENT LEVELS, PER
PREVIOUS FORECAST. WE HAVE INCREASED SKY COVER IN GRIDS THROUGH
THIS EVENING HOWEVER, AS DENSE CLOUD COVER EXTENDS WELL INTO
ONTARIO PROVINCE AND OHIO. LATEST RAP SOUNDINGS SUGGEST MAINLY
CLOUDY SKIES FOR INTERIOR FA THROUGH MIDNIGHT.
4 AM TUE UPDATE... MAIN PCPN SHIELD CONTS TO QUICKLY EXIT EARLY
THIS MRNG...AS AN UPR-LVL WAVE LIFTS INTO NEW ENG...AND A SFC COLD
FRNT PUSHES OFF THE EAST COAST.
IN THE WAKE OF THE AFOREMENTIONED SYSTEMS...A W TO NW FLOW AND STG
LOW-LVL CAA WILL PREVAIL FOR THE REST OF THE MRNG HRS.
HOWEVER...DESPITE THIS SYNOPTIC SET-UP...THE LAKE RESPONSE SHOULD
BE LIMITED...AS PRONOUNCED DRY ADVECTION OCCURS ABV 900 MB...AND
THE MIXED LYR FLOW REMAINS FAIRLY SHEARED IN A DIR SENSE.
THUS...WE EXPECT NOTHING MORE THAN SCTD -SHSN/FLRYS...WITH LIMITED
ACCUMS (UNDER AN INCH) ACRS THE MOHAWK VLY/SRN TUG HILL RGN.
FROM THE TWIN TIERS SWD...AM CLDS SHOULD BREAK FOR SOME AFTN
SUNSHINE...WITH STG DRYING/DVM AT PLAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
415 AM UPDATE... QUIET WX TO PREVAIL THIS PD.
WRLY LOW-LVL FLOW PERSISTS TNT...WED...AND INTO WED EVE.
AGN...THOUGH...SHALLOW MOIST/POOR DZ MECHANICS AND DIR SHEAR IN
THE VERTICAL SHOULD SERIOUSLY MUTE ANY LAKE RESPONSE. THE "BEST"
COVERAGE OF SHSN COULD OCCUR WED AFTN INTO THE EARLY EVE IN OUR
FAR NRN ZNS...AS A PROGRESSIVE NRN STREAM UPR WAVE COMES
THROUGH...ALG WITH A WEAK SFC TROUGH. VERY MINOR ACCUMS...IF
ANY...ARE FORESEEN.
BY THU...RIDGING COMES IN...ALG WITH BACKING LOW-LVL FLOW AND WAA.
THUS...HIGH TEMPS SHOULD MODERATE INTO THE LWR 40S MANY LOCALES BY
THU AFTN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
XTNDD PD BEGINS WIL A FLAT RDG OVER THE MID ATLANTIC AND A WLY
FLOW OVER THE FCST AREA. A LOW DVLPG OVER THE WRN GREAT LAKES WILL
BEGIN TO PUSH MOISTURE INTO THE AREA LATE SAT...CONTG THRU THE END
OF THE PD. SYSTEM IS A SLOW MVR WITH A CLSD UPR LOW...AND DFCLT TO
FCST AS THE DETAILS OF A CSTL DVLPMT LATE IN THE PD ARE STILL
FUZZY. IN ANY EVENT...MODELS ARE IN SOMEWHAT BETTER AGREEMENT AND
HAVE TRENDED TWRD A COOLER SOLN AS A CONFLUENT UPR FLOW OVER NEW
ENG BLDS A SFC HIPRES NORTHEAST OF THE AREA KEEPING COLDER AIR IN
PLACE. THIS WILL CAUSE MIXED PCPN AT TIMES AND THE LOW MEANDERS
EWRD THRU THE PD.
GNRLY FLWD HPC GUID THRU THE PD WHICH WAS CLOSER TO THE MEX GUID
THIS TIME ARND...LDG TO HIER CONFIDENCE IN THE TEMP FCST. CHANCE
POPS THUR THE PD WERE ALSO IN BETTER AGREEMENT.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
WLY FLOW OFF THE GREAT LAKES IS KEEPING LL MOISTURE IN THE AREA
THIS AFTN. THIS HAS RESULTED IN MSTLY MVFR CIGS ALIONG WITH SOME
VERY LGT SNOW SHWRS. MDL SNDG FCSTS SHOW LTL CHG OVRNGT...WITH
PERHAPS EVEN SOME LWRG OF CIGS AS WE LOSE MIXING AND WINDS GO LGT.
XCPTN WILLBE AT AVP AS SOMEWHAT DRIER AIR MAY RESULT IN A SCT CLD
DECK. AFT 12Z...FLOW BWECOMES MORE SWLY AND STRENGTHENS WHICH MAY
BRING SOME LE INTO RME...OTRW THIS FLOW WILL BEGIN A SLOW IMPRVMT
IN CONDS THRU THE END OF THE PD...AND BEYOND.
OUTLOOK...
WED NGT-SAT...VFR.
SUN...MVFR/IFR IN RAIN AND SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
256 PM CST TUE DEC 11 2012
.SHORT TERM... /TONIGHT THROUGH FRIDAY/
THE FORECAST CHALLENGE FOR THE SHORT TERM WILL BE OVERNIGHT LOWS
AND SNOWFALL AMOUNTS ACROSS THE FAR NORTHERN ZONES. MODELS ARE IN
GENERAL AGREEMENT TODAY...ALTHOUGH THE RUC HAS A MUCH BETTER
HANDLE ON CLOUDS CURRENTLY ACROSS WESTERN NORTH DAKOTA. THEREFORE
WILL USE A FORECAST BLEND.
MAJORITY OF OUR CWA IS CLEAR OR UNDER THIN STRATUS...WITH SOME
REMNANTS OF TODAYS CLOUD COVER OVER THE CENTRAL VALLEY EXTENDING
EASTWARD INTO SOUTHERN BELTRAMI COUNTY. RADAR ECHOES HAVE BEEN
WEAK TODAY...AND DESPITE SNOW AT SEVERAL METARS IN WEST CENTRAL MN
EARLIER THIS AFTN...CONTINUE TO EXPECT THIS TO BE FLURRY ACTIVITY
WITH NO ACCUMULATION.
TONIGHT...THE LATEST RUC HAS THE BEST HANDLE ON MOISTURE ADVECTION
AND PLACEMENT OF CLOUDS JUST WEST OF THE MISSOURI RIVER IN WRN ND.
WILL CONSIDER THE RUC TIMING OF CLOUDS INTO MY WESTERN ZONES FOR
FCST LOWS...WHICH WILL OCCUR EARLY IN THE EVENING AS CLOUDS
ENCROACH FROM THE WEST. THINK THE NAM IS TOO FAST AND THE GEM HAS
A DECENT HANDLE ON THE COLDEST TEMPS...BUT THE LATTER MAY STILL BE
TOO FAST IN BRINGING CLOUD COVER IN. THUS WILL LEAN TOWARD GEM
SOLUTION BUT CUT TEMPS FURTHER DOWN ALONG WESTERN ZONES AS I
BELIEVE WE WILL HAVE A COUPLE OF HOURS FOR TEMPS TO DROP BEFORE
CLOUDS MOVE IN...GIVEN SNOW ESP IN THE NORTHWEST...AND OVERNIGHT
TEMPS BEGIN TO RISE. COLDEST TEMPS SHOULD BE IN NORTHWEST
MINNESOTA NORTH OF THE PRESENT CLOUDS. COULD SEE TEMPS DOWN INTO
DOUBLE DIGITS...PER GEM GUIDANCE...BUT GENERALLY KEPT TEMPS IN THE
5 TO 10 BELOW RANGE.
LOW PRESSURE WILL THEN MOVE ACROSS THE NORTHERN TIER WITH MODEST
WARM ADVECTION / ISENTROPIC LIFT AFT 03Z. MODELS IN DECENT
AGREEMENT ON PLACEMENT OF SNOWFALL...WITH THE NORTHERN VALLEY
EXPECTED TO RECEIVE THE MOST AS NORTHEASTERN ND EXPECTED TO HAVE
THE STRONGEST ISENTROPIC LIFT. GENERALLY 1 TO 3 INCHES ACROSS THE
NORTH AS THIS SYSTEM MOVES BY. CLOUD ADVECTION WILL CAUSE MOST
SITES TO SEE OVERNIGHT TEMPS BEGIN TO RISE BY 06Z TO 09Z (EARLIER
IN THE WEST). BEST ISENTROPIC LIFT / LOWEST CONDENSATION PRESSURE
DEFICITS GENERALLY NORTH OF THE HWY 2 CORRIDOR SO EXPECT A SHARP
CUTOFF ACROSS SOUTHERN ZONES...BUT SOME FLURRIES ARE POSSIBLE.
WEDNESDAY AND WED NIGHT...MODELS GENERALLY PULL PRECIP OUT OF REGION BY
EARLY AFTERNOON TUESDAY. THUS HAVE REDUCED POPS FOR AFTN HOURS.
NORTHERLY FLOW THEN USHERS IN A COLD CANADIAN AIR MASS. MODELS
ARE PRODUCING PRECIP WEDNESDAY NIGHT AS A JET MAX MOVES ACROSS
SOUTH DAKOTA. WHILE ISENTROPIC SURFACES DO BRING A SWATH OF LOWER
CONDENSATION PRESSURE DEFICITS ACROSS THE AREA...ISENTROPIC LIFT
IS WEAK. HOWEVER DO SEE POTENTIAL FOR MORE STRATUS AND FLURRIES AS
MODELS INDICATE LOW LEVEL MOISTURE MOVING IN AFT 06Z. WILL
CONTINUE FLURRIES FOR WED NIGHT.
THURSDAY... RETURN FLOW WILL SLOWLY BEGIN OVER DEVILS LAKE REGION
ON THU. GFS SHOWS MODEST ISENTROPIC LIFT OVER WESTERN
ZONES...WITH MODERATELY LOW CONDENSATION PRESSURE DEFICITS WHILE
THE NAM IS DRY. WILL CONTINUE SLIGHT CHANCE POPS IN THE
WEST...HOWEVER CONFIDENCE FOR MEASURABLE PRECIP WITH THIS WAVE IS
LOW GIVEN MODEL DIFFERENCES.
FRIDAY...SOUTHEASTERLY FLOW AND INCREASED SOLAR SHOULD ALLOW TEMPS
TO RISE INTO THE UPPER TEENS IN THE NORTH AND LOWER 20S ACROSS THE
SOUTH...WITH FRIDAY BEING THE WARMEST DAY OF THE SHORT TERM.
.LONG TERM... /FRIDAY NIGHT THROUGH TUESDAY/
PSEUDO SPLIT FLOW THROUGH THE PERIOD WITH THE MAIN STORM TRACK SOUTH
OF FA THIS WEEKEND. FARTHER NORTH SOLUTIONS OF GEM/ECMWF HAVE FAR
SE/E FA ON NORTHERN FRINGE OF SNOW SHIELD SO WILL MAINTAIN LOW POPS
THIS AREA. TEMPERATURES LOOK SEASONAL WITH NO REAL COLD AIR
INTRUSION THROUGH THE PERIOD.
&&
.AVIATION...
CLEARING CONTINUES TO SPREAD FROM NW-SE WITH MOST OF FA VFR BY LATE
AFTERNOON. VFR CIGS WILL SPREAD IN LATER TONIGHT WITH -SN DEVELOPING
ACROSS FAR NORTH LATE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER/VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1028 AM CST TUE DEC 11 2012
.DISCUSSION...
MORNING UPDATE WILL ADDRESS SKY TRENDS AND TEMPS. CURRENT VIS
SATELLITE SHOWING SOME CLEARING OVER NORTH CENTRAL AND NORTHEAST
NORTH DAKOTA WITH MORE CLOUD COVER ENCROACHING INTO THE FAR
WESTERN PART OF THE STATE. WILL REDUCE SKY SOMEWHAT BUT EXPECT
THIS TO BE 4 TO 6 HOURS OF PARTLY CLOUD BEFORE CLOUDS MOVE BACK IN
EARLY EVENING. COLDEST TEMPS SO FAR THIS MORNING IN THE FOOTHILLS
OF THE TURTLE MTS. WHILE RUC IS TOO COLD...IT IS DOING REASONABLY
WELL ON HIGHLIGHTING COLD SPOTS THIS MORNING SO WILL USE ITS TEMPS
FOR GUIDANCE...WARMING THINGS UP A DEG OR TWO AS NECESSARY.
CURRENT SN AT GFK IS VERY FINE FLURRIES...THUS NO PLAN TO UPDATE
TO MEASURABLE SNOWFALL THIS MORNING. VERY LITTLE ON RADAR...SO
FLURRIES LOOK GOOD.
&&
.AVIATION...
PATCHY STRATUS CONTINUES TO COVER THE SOUTHERN VALLEY AND WEST
CENTRAL MINNESOTA. MUCH OF NORTH CENTRAL NORTH DAKOTA APPEARS
CLEAR ON SATELLITE HOWEVER MORE CLOUD COVER TO THE WEST WILL MOVE
IN BY EVENING. EXPECT TO SEE IN AND OUT CLOUDS FROM THE VALLEY
WEST TODAY. STRATUS OVER MINNESOTA IS VERY THIN...WITH LAND
FEATURES APPEARING ON VIS SAT...BUT NONETHELESS MVFR CIGS FOR THE
COMING HOURS. ANY FLURRIES CREATING RESTRICTIONS TO VIS WILL NOT
BE WIDESPREAD ENOUGH TO INCLUDE IN THE TAFS AT THIS POINT.
CEILINGS COULD LIFT A BIT BY AFTERNOON...BUT REMAIN ON THE LOWER
END OF VFR. LIGHT AND VARIABLE WINDS WILL PICK UP FROM THE SOUTH
AFTER 00Z AT 10 KTS OR SO.
&&
.PREV DISCUSSION... /ISSUED 345 AM CST TUE DEC 11 2012/
SHORT TERM...
CHANCES FOR SNOW AND TEMPERATURES WILL BE THE PRIMARY FORECAST
ISSUE FOR THE PERIOD.
NORTHWESTERLY FLOW ALOFT WILL CONTINUE TODAY WITH WEAK HIGH
PRESSURE OVER THE REGION. MODELS SHOW QUITE A BIT OF LOW LEVEL
MOISTURE UNDER THE SFC HIGH...WHICH FITS WITH THE AREAS OF STRATUS
SEEN ON SAT LOOP OVER ND AND SOUTHERN CANADA. THERE HAVE ALSO BEEN
SEVERAL LOCATIONS UNDER THE STRATUS REPORTING FLURRIES. THINK THAT
THIS TREND WILL CONTINUE INTO THE MORNING HOURS SO BUMPED UP CLOUD
COVER AND INCLUDED A FLURRY MENTION. THERE WILL BE SOME DECENT
COLD AIR ADVECTION ON THE BACKSIDE OF THE DEPARTING SFC
TROUGH...MOSTLY OVER THE NORTHEASTERN CWA. WITH CLOUDS AND SNOW
COVER KEPT HIGHS MOSTLY IN THE SINGLE DIGITS WITH SOME AREAS
SEEING NON-DIURNAL TEMPERATURES.
TONIGHT...THE UPPER FLOW BECOMES MORE SPLIT WITH A NORTHERN BRANCH
WEAK SHORTWAVE MOVING THROUGH SOUTHERN CANADA. THIS SHOULD HELP
STRENGTHEN THE SFC LOW OVER THE WESTERN PLAINS...WITH STRONG WARM
AIR ADVECTION OVER MOST OF THE CWA. THINK THAT MANY AREAS WILL SEE
STEADY OR RISING TEMPS OVERNIGHT. THERE SHOULD BE SOME GOOD
ISENTROPIC LIFT OVER THE NORTHERN CWA TONIGHT...WITH THE BEST
CONDENSATION PRESSURE DEFICITS ENTERING THE DEVILS LAKE BASIN
SOMETIME AROUND MIDNIGHT. MODELS COMING INTO TO BETTER AGREEMENT
ON THE QPF OVER THE NORTHERN CWA...ALTHOUGH THERE ARE STILL SOME
DIFFERENCES IN EXACT TIMING AND IF THE HIGHEST AMOUNTS WILL BE
NORTH OR SOUTH OF THE CANADIAN BORDER. BUMPED UP POPS FOR THE
NORTHERN CWA...MAINLY DURING THE LATE TONIGHT/TOMORROW MORNING
TIME FRAME. A COUPLE OF INCHES OF ACCUMULATION ALONG THE CANADIAN
BORDER CONTINUES TO SEEM MOST LIKELY AT THIS POINT.
THE UPPER SHORTWAVE CONTINUES TO MOVE THROUGH SOUTHERN
CANADA WEDNESDAY...WITH ANOTHER WEAK SHORTWAVE COMING IN QUICKLY
FROM THE WEST. KEPT POPS GOING IN THE NORTHERN CWA THROUGHOUT THE
DAY ON WEDNESDAY. THE GFS TRIES TO BRING COLD AIR DOWN A BIT
FASTER THAN THE NAM AND ECMWF...WHICH KEEP THE CWA IN THE WARM AIR
FOR MUCH OF THE DAY. AS THE GFS SEEMS TO BE AN OUTLIER WILL LEAN
TOWARDS KEEPING WEDNESDAY AS THE WARMEST DAY...BUT WILL HAVE TO
KEEP AN EYE ON TH SITUATION.
THE COLD AIR MOVES IN WEDNESDAY NIGHT...WITH A FAIR AMOUNT OF LOW
LEVEL MOISTURE...SO THINK ANOTHER NIGHT OF STRATUS AND FLURRIES IS
POSSIBLE SO KEPT THE MENTION WE HAD GOING. ANOTHER WEAK SHORTWAVE
WILL MOVE THROUGH SOUTHERN CANADA THURSDAY INTO THURSDAY
NIGHT...SO KEPT SOME LOW POPS GOING FOR THE FAR NORTH ALTHOUGH THE
BEST CHANCES FOR ANYTHING SIGNIFICANT WILL BE IN MANITOBA. WITH
MORE COLD AIR MOVING IN HIGHS THURSDAY WILL BE KNOCKED BACK DOWN
INTO THE TEENS WITH LOWS MAINLY IN THE SINGLE DIGITS.
LONG TERM (FRIDAY-MONDAY)...
FAIRLY TRANQUIL WEATHER IS EXPECTED THROUGHOUT THIS PERIOD. FORECAST
CONFIDENCE QUICKLY DECREASES THOUGH FOR SUNDAY/MONDAY WITH COMPLEX
SPLIT FLOW PATTERN ACROSS THE NATION. INITIALLY...00Z MODELS ARE IN
GOOD AGREEMENT FOR FRIDAY SHOWING WEAK RETURN FLOW/WARM AIR
ADVECTION...WITH TEMPS MODERATING CLOSER TO NORMAL. ON SATURDAY...A
SOUTHERN STREAM DISTURBANCE IS EXPECTED TO LIFT NORTHEAST...WITH THE
SFC LOW TRACKING FROM THE CENTRAL PLAINS TO THE WESTERN GREAT LAKES
BY EARLY SUNDAY. THIS TRACK WOULD KEEP MUCH OF THE PRECIP FROM THIS
SYSTEM SOUTH AND EAST OF THE REGION...AND KEPT DRY FORECAST INTACT.
WENT WITH A DRY FORECAST BEYOND SATURDAY...ALTHOUGH SIGNIFICANT MODEL
SPREAD LEADS TO VERY LOW FORECAST CONFIDENCE. MODELS INDICATE A
PRONOUNCED SPLIT FLOW PATTERN CONTINUING WITH AN ENHANCED SOUTHERN
STREAM. MODELS DIFFER QUITE A BIT ON THE TIMING AND SUBSEQUENT
AMPLIFICATION/EVOLUTION OF SHORTWAVE TROUGHS...ALTHOUGH BOTH THE 00Z
GFS/ECMWF DO SHOW ANOTHER SIGNIFICANT SHORTWAVE TROUGH DIVING INTO
THE SOUTHERN PLAINS BY LATE IN THE PERIOD. WITH RELATIVELY ZONAL
FLOW ALOFT...NO SIGNIFICANT COLD AIR INTRUSIONS WOULD BE EXPECTED
THROUGH THE END OF THE PERIOD...WITH TEMPS NEAR NORMAL OR EVEN
SLIGHTLY ABOVE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
257 PM CST TUE DEC 11 2012
.SYNOPSIS...QUIET WEATHER WITH A LITTLE ABOVE NORMAL TEMPERATURES
FOR THE REST OF THE WORK WEEK...THEN SOME PRECIPITATION THIS
WEEKEND.
THE LARGE SCALE PATTERN ACRS NOAM WL GRADUALLY TRANSITION INTO A
SPLIT FLOW REGIME BY THIS WEEKEND. THIS WL ALLOW TEMPS TO WARM
BACK TO SOMEWHAT TO ABV NORMAL. THE MAIN PCPN EVENT WL COME WITH
SRN STREAM CYCLONE TRACKING THROUGH THE RGN THIS WEEKEND.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY.
SNOW POTENTIAL AND TEMPERATURES WERE THE MAIN CONCERNS FOR THE SHORT
TERM. WV IMAGERY SHOWED SHORT WAVES PASSING THROUGH THE WESTERN
GREAT LAKES REGION TODAY. MODELS SEEMED TO AGREE THAT THE SHORT
WAVE OVER MINNESOTA EARLY THIS AFTERNOON WOULD PRODUCE SOME QPF
ACROSS THE FAR SOUTHERN PART OF THE FORECAST AREA THIS EVENING AS
IT MOVES THROUGH WISCONSIN. HAVE OPTED TO INCLUDE POPS A BIT
FARTHER NORTH IN TEXT PRODUCTS THAT IN GRIDS...TO PROVIDE SOME
MARGIN FOR ERROR.
A NARROW SURFACE RIDGE IS EXPECTED TO PUSH EAST TONIGHT...RESULTING
IN DECREASING WINDS. MODELS WERE KEEPING SOME LOWER LEVEL MOISTURE
AROUND SO HAVE 50 PERCENT OR HIGHER SKY COVER THROUGHOUT THE
NIGHT. THE LIGHT WINDS SHOULD STILL ALLOW TEMPERATURES TO FALL INTO
THE SINGLE DIGITS AND TEENS WITHOUT MUCH CLEARING. IF CLOUDS DO
NOT HANG AROUND TEMPERATURES WILL LIKELY END UP MUCH COLDER...EVEN
WITH WAA OCCURRING.
THERE SHOULD STILL BE SOME MIDDLE AND HIGH CLOUDS ACROSS THE AREA
ON WEDNESDAY ACCORDING TO MODEL TIME/HEIGHT SECTIONS SO FULL
SUNSHINE IS NOT LIKELY. CONTINUED WARM ADVECTION SHOULD RESULT IN
WARMER HIGH TEMPERATURES THAT TODAY...AT OR A SLIGHTLY WARMER THAN
NORMAL. 850MB BAROCLINIC ZONE SHOULD BE NORTH OF THE STATE AND
THERE WAS NO QPF SHOWING UP ON GRAPHICS SO HAVE KEPT THE FORECAST
DRY DURING THE DAY.
.LONG TERM...WED NGT THRU NEXT TUE. RELATIVELY QUIET WX EXPECTED
FOR THE REST OF THE WORK WEEK. WLY FLOW ALOFT WL ALLOW TEMPS TO
WARM BACK TO AT LEAST SOMEWHAT ABV NORMAL...THOUGH DEEP SNOWCOVER
TO THE WEST AND VERY LOW SUN ANGLE AT THIS TIME OF YR WL KEEP THE
WARMING IN CHECK.
SRN STREAM CYCLONE TRACKING THROUGH THE RGN WL PROBABLY BRING PCPN
TO THE AREA THIS WEEKEND. MODELS WERE SIMILAR IN SHOWING THE
SYSTEM AFFECTING THE AREA...BUT DIFFERED SOMEWHAT ON THE TRACK.
PCPN CHCS WL BE SOMEWHAT GREATER OVER THE S AND DECR TO THE N. AS
TYPICAL OF SUCH SYSTEMS...PCPN TYPE WL BE A MAJOR FCST ISSUE.
&&
.AVIATION...SHORT WAVES PASSING THROUGH THE AREA TODAY WERE
PRODUCING SNOW SHOWERS AND FLURRIES...ALONG WITH MAINLY MVFR CIGS
AND MVFR/IFR VSBYS. RUC13 SHOWED A TENDENCY FOR SHORT WAVES TO
WEAKEN...OR AT LEAST PRODUCE SMALL OR NO QPF AS THEY MOVE INTO THE
EASTERN PART OF THE FORECAST AREA. MVFR CIGS MAY PERSIST THROUGH
THE EVENING BEFORE LOW CLOUDS START TO CLEAR...LEAVING JUST SOME HIGH
CLOUDS. LOOKS DRY AFTER 06Z AND WEDNESDAY SHOULD BE DRY WITH VFR
CONDITIONS PREVAILING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MG/SKOWRONSKI
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1216 PM CST TUE DEC 11 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH WEDNESDAY...SNOW CHANCES TODAY AND
EARLY TONIGHT...AND SKY COVER AND TEMPERATURES THROUGHOUT THE
PERIOD...ARE THE MAIN FCST CONCERNS.
WV IMAGERY SHOWED A S/W TROF MOVG THROUGH NE WI...AND ADDITIONAL SHORT-
WAVES LOCATED UPSTREAM OVER MINNESOTA AND SE SASK. THESE DISTURBANCES
WILL PASS THROUGH GRB CWA TODAY INTO THIS EVENING...PRODUCING SCT SNOW
SHOWERS AND FLURRIES. THERE WILL BE PERIODIC BREAKS IN THE SNOW SHOWERS
DUE TO SUBSIDENCE BETWEEN THE WAVES. EVEN THOUGH THERE IS ONLY A SMALL
CHANCE OF MEASURABLE WATER EQUIVALENT PCPN...TEMPERATURES WITHIN
THE MOISTURE LAYERS ARE FAVORABLE FOR DENDRITES...SO MOST PLACES
SHOULD RECEIVE A DUSTING TO A HALF INCH OF FLUFFY SNOW. THE SNOW
WILL END AS THE FINAL S/W TROF EXITS THE REGION AND A RIDGE OF
HIGH PRESSURE ARRIVES AFTER MIDNIGHT. THIS RIDGE SHOULD BRING
PARTIAL CLEARING OVERNIGHT...LEADING TO COOLER TEMPS IN THE SINGLE
DIGITS AND TEENS.
WAA WILL CAUSE H8 TEMPS TO WARM TO AROUND ZERO C BY WEDNESDAY...BUT
FCST SOUNDINGS ONLY SUPPORT SHALLOW MIXING TO 950-925 MB. LINGERING
SNOW PACK MAY HINDER A GOOD WARM-UP...SO DIDN`T STRAY TOO FAR FROM
PREVIOUS FCST HIGHS...WHICH RANGED FROM THE UPPER 20S TO MID 30S.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT MONDAY.
THE LATEST GFS ENSEMBLE MEAN INDICATES THAT SPLIT FLOW WILL DOMINATE
THE WEATHER PATTERN ACROSS NORTH AMERICA THROUGHOUT THE EXTENDED
FORECAST. WITH THE STATE OF WISCONSIN LOCATED BETWEEN THE NORTHERN
STREAM WHICH WILL GENERALLY RESIDE JUST NORTH OF THE CANADIAN
BORDER...AND THE SOUTHERN STREAM OVER THE MID-MISSISSIPPI VALLEY...A
PERIOD OF QUIET WEATHER IS EXPECTED. THE ONLY WEATHER-MAKER OVER
THIS PERIOD WILL OCCUR EARLY THIS WEEKEND WHEN A SYSTEM EJECTS OUT
OF THE SW CONUS AND MOVES ACROSS THE CENTRAL MISSISSIPPI VALLEY TO
THE SOUTH-CENTRAL GREAT LAKES. THE GFS IS QUITE FAST...BUT ITS
TRACK LOOKS LIKE IN THE MIDDLE OF THE GUIDANCE. WILL TAKE A BLEND
OF THE ECMWF/GEM.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...A WEAK AREA OF LOW PRESSURE
WILL MOVE FROM NORTHERN MINNESOTA AND ACROSS LAKE SUPERIOR WEDNESDAY
NIGHT THROUGH THURSDAY MORNING. FORCING WILL RESIDE ALONG AND NORTH
OF THE SURFACE LOW TRACK...WHILE DRY LOW LEVEL AIR WILL PUSH NORTH
ACROSS THE STATE FROM THE SOUTHERN PLAINS. THE DRY AIR WILL KEEP
THE AREA PRECIP-FREE...THOUGH PARTLY CLOUDY CONDITIONS WILL REMAIN
THANKS TO A CIRRUS SHIELD...AND SW WINDS WILL BE QUITE BREEZY.
TEMPS WILL BE MILD WITH HIGHS IN THE MID TO UPPER 30S ON THURSDAY.
A COLD FRONT EXTENDING SW FROM THE SURFACE LOW WILL SLOWLY SAG INTO
THE REGION THURSDAY NIGHT. A BKN LOW CLOUD DECK WILL TRY TO MOVE
INTO N-C WISCONSIN BEHIND THE FRONT. BUT OTHERWISE...A LACK OF
FORCING ALOFT WILL PREVENT ANY THREAT OF PRECIP. LOWS IN THE MID
TEENS TO LOWER 20S.
REST OF THE FORECAST...DIFFUSE COOL FRONT WILL SLOWLY SAG SOUTH
ACROSS THE FORECAST AREA FRIDAY INTO FRIDAY NIGHT WITHOUT MUCH
OF AN IMPACT EXCEPT FOR A LOW STRATUS DECK THAT MAY SLIDE INTO
NORTHERN WISCONSIN. HIGH CLOUDS WILL BE INCREASING FRIDAY NIGHT AS
A STORM SYSTEM MOVES ACROSS THE CENTRAL PLAINS. THERE IS A SMALL
CHANCE THAT PRECIP FROM THE SYSTEM WILL REACH CENTRAL WISCONSIN LATE
FRIDAY NIGHT...BUT WILL PROBABLY HAVE TO WAIT UNTIL SATURDAY WHEN
LOW PRESSURE MOVES ACROSS CENTRAL TO NORTHEAST ILLINOIS. ISENTROPIC
ASCENT WILL BE INCREASING AHEAD OF THIS SYSTEM ON SATURDAY TO SPREAD
PRECIP NORTHEAST ACROSS THE REGION. PRECIP TYPE WILL AGAIN BE TOUGH
TO NAIL DOWN...BUT MILD PACIFIC AIR IN PLACE COMBINED WITH A DAYTIME
ARRIVAL OF THE PRECIP MAKES ME THINK A RAIN/SNOW MIX ACROSS MUCH OF
THE AREA EXCEPT FOR NORTH-CENTRAL WISCONSIN. PRECIP WILL CONTINUE
INTO SATURDAY NIGHT WHEN COOLING LOW LEVEL TEMPS WILL LEAD TO ACCUM
SNOW CHANCES FARTHER SOUTH. LIGHT SNOW SHOWERS AND FLURRIES WILL
CONTINUE THROUGH SUNDAY THANKS TO CYCLONIC FLOW. QUIET CONDITIONS
RETURN ON MONDAY.
&&
.AVIATION...SHORT WAVES PASSING THROUGH THE AREA TODAY WERE
PRODUCING SNOW SHOWERS AND FLURRIES...ALONG WITH MAINLY MVFR CIGS
AND MVFR/IFR VSBYS. RUC13 SHOWED A TENDENCY FOR SHORT WAVES TO
WEAKEN...OR AT LEAST PRODUCE SMALL OR NO QPF AS THEY MOVE INTO THE
EASTERN PART OF THE FORECAST AREA. MVFR CIGS MAY PERSIST THROUGH
THE EVENING BEFORE LOW CLOUDS START TO CLEAR...LEAVING JUST SOME HIGH
CLOUDS. LOOKS DRY AFTER 06Z AND WEDNESDAY SHOULD BE DRY WITH VFR
CONDITIONS PREVAILING.
MG
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$