Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/25/14
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
944 AM MST TUE DEC 23 2014
.SYNOPSIS...
HIGH PRESSURE OFF THE WEST COAST WILL RESULT IN NEAR NORMAL
TEMPERATURES WITH VARYING AMOUNTS OF HIGH CLOUDS THROUGH THE MIDDLE
OF THE WEEK. BY THURSDAY...THE STORM PATTERN WILL BECOME MORE ACTIVE
ACROSS THE WEST COAST AS A SERIES OF SHORTWAVES SWEEP THROUGH THE
REGION. COOLER TEMPERATURES AND INCREASED CLOUDINESS ARE EXPECTED
THURSDAY INTO FRIDAY. DRY...AND POTENTIALLY MUCH COOLER...WEATHER IS
EXPECTED BY THE COMING WEEKEND.
&&
.DISCUSSION...
VISIBLE SAT IMAGERY CURRENTLY SHOWS GENERALLY CLEAR SKIES OVER
ENTIRE FORECAST AREA...THE RESULT OF SUBSIDENCE ASSOCIATED WITH
UPPER LEVEL RIDGE BUILDING INTO THE SOUTHWEST. MODEL SOUNDINGS
INDICATE CONSIDERABLE DRYING OF THE AIRMASS OVER THE REGION DURING
THE LAST 24-HOURS...WITH PWAT DROPPING TO AROUND ONE QUARTER OF AN
INCH. WIND PROFILE FROM THE SFC TO ABOVE 3H REMAINS NORTH TO
NORTHEAST...KEEPING COOLER AIR OVER MUCH THE REGION.
AS INDICATED IN EARLIER DISCUSSION...TIGHTENING LOW LEVEL SURFACE
GRADIENT WILL RESULT IN PERIODS OF BREEZY TO WINDY CONDITIONS...
PARTICULARLY DOWN THE COLORADO RIVER VALLEY AND OVER SOUTHERN GILA
COUNTY. REAL-TIME MESOANALYSIS DATA INDICATES SOME INCREASING WINDS
ALREADY IN THESE AREAS. COLD AIR BOUNDARY OVER SOUTHERN GILA COUNTY
HAS BEEN NUDGING TO THE SOUTHWEST...THOUGH NOTICED THE HRRR DOESNT
PUSH THIS BOUNDARY MUCH FURTHER SOUTH. EXPECT ONLY REAL AFFECT THEN
WILL BE THE STRONGER WINDS ALREADY MENTIONED.
TEMPERATURES ACROSS THE REGION THIS MORNING WERE GENERALLY WARMER
THAN YESTERDAY AT THIS TIME...PARTICULARLY OVER SOUTHWEST ARIZONA
AND SOUTHEAST CALIFORNIA...WHERE OBSERVATIONS WERE 10 DEGREES OR
MORE WARMER THAN 24-HOURS AGO. HAD TO MAKE SOME ADJUSTMENTS IN OUR
MAX TEMPERATURE FORECASTS FOR TODAY...PRIMARILY IN THE WESTERN THIRD
OF THE FORECAST AREA...SO GRIDS WOULD BETTER TRACK CURRENT TEMPS AND
EXPECTED TRENDS. DEWPOINT TEMPERATURES FIRST PERIOD WERE ALSO
TWEAKED. THE REMAINDER OF OUR FORECAST PACKAGE CURRENTLY IS ON
TRACK.
&&
.PREV DISCUSSION...
ISSUED AT 455 AM MST TUE DEC 23 2014
BROAD TROUGHING COVERS MUCH OF THE CONUS THE MORNING...WITH HIGH
AMPLITUDE RIDGING EXPANDING ACROSS THE NORTHEASTERN PACIFIC FROM OFF
THE BAJA/SOCAL COAST UP THROUGH SOUTHERN BRITISH COLUMBIA. EARLY AM
SFC ANALYSIS PLOTS A STRENGTHENING SFC HIGH...AROUND 1032MB...OVER ID
WITH TIGHTENED NORTHERLY SFC PRESSURE GRADIENTS ALREADY DROPPING INTO
NORTHERN AZ AND THE CO RIVER VALLEY. NORTHERLY WINDS BEGAN LAST
EVENING AT BLYTHE AND SITES UPSTREAM AND WILL CONTINUE FOR MUCH OF
THE DAY AS THE SURFACE HIGH STRENGTHENS AND SLIDES FURTHER INTO THE
GREAT BASIN. MEANWHILE TO OUR NORTHEAST AND EAST...STRONG 500MB/300MB
JET ENERGY ALONG A SHORTWAVE IMPULSE IS AIDING PRECIP ACTIVITY ACROSS
CO AND NM. MUCH AZ REMAINS UNDER PARTIAL INFLUENCE OF THE UPPER
RIDGE...WITH SUBSIDENT FLOW PRODUCING CLEAR MORNING SKIES. EARLY AM
TEMPERATURES ARE FAIRLY MILD ALONG THE CO RIVER VALLEY...THANKS TO
THE OVERNIGHT WINDS...WITH LOCATIONS LIKE DESERT CENTER AND BLYTHE
CA STILL REPORTING TEMPERATURES IN THE 60S.
TODAY AND WEDNESDAY...
STRONG LOW LEVEL PRESSURE GRADIENTS WILL PERSIST GUSTY NORTH-
NORTHEAST WINDS ACROSS MOST OF OUR FORECAST AREA...STRONGEST DOWN THE
COLORADO RIVER VALLEY AND OVER SOUTHERN GILA COUNTY WHERE RIDGE TOP
WINDS COULD BRIEFLY APPROACH 40 MPH. CO RIVER VALLEY WINDS SHOULD
INCREASE A FEW HOURS AFTER SUNRISE WITH SUDDEN GUSTS TO 30
MPH...SIMILARLY IN THE MOUNTAIN VALLEYS OF SOUTHERN GILA COUNTY. THE
REMAINDER OF THE LOWER DESERTS INCLUDING PHOENIX ARE FORECAST IN THE
BREEZY CATEGORY...10 TO 20 MPH. TRAILING SHORTWAVE ENERGY OFF THE
BROAD CONUS TROUGH WILL FORCE A BACKDOOR COLD FRONT TO THE SOUTHWEST
THROUGH AZ TODAY BEFORE THE DISTURBANCE BOTTOMS OUT OVER WEST TEXAS
BY LATER THIS AM. THE FRONT WILL BE DRY...BUT THE INTRUSION OF DRIER
COLD AIR WILL OFFSET ANY WARMING EXPECTED OVER OUR SOUTH-CENTRAL AZ
ZONES...WITH JUST A FEW DEGREES OF COOLING EXPECTED ACROSS SOUTHEAST
CALIFORNIA AND THE LOWER CO RIVER VALLEY. WINDS WILL ABATE BY
WEDNESDAY MORNING AND COOLER DAYTIME TEMPS BACK INTO THE 60S WILL
PREVAIL ACROSS THE LOWER DESERTS.
THURSDAY THROUGH INTO EARLY NEXT WEEK...
ANOTHER PASSING COOL FRONT AND SWIFT MOVING PACIFIC TROUGH WILL SWEEP
INTO THE REGION FROM THE NORTHWEST THURSDAY. LOWERING HEIGHTS AND
THICKNESSES COULD DRAW SOME MOISTURE IN FROM OFF THE PACIFIC...BUT
FCST PWATS HAVE BEEN DRAWN DOWN AROUND 0.50 OR LESS. ELEVATED WEST-
SOUTHWEST DAYTIME BREEZES AND INCREASING CLOUDS ARE EXPECTED FORECAST
AREA WIDE. THE REMOTE CHANCE FOR LIGHT SHOWER ACTIVITY STILL LINGERS
THE EASTERN AZ HIGHER TERRAIN...INCLUDING THE FOOTHILLS ACROSS
EASTERN PINAL AND SOUTHERN GILA COUNTY. UPPER TROUGH WILL LINGER OVER
THE FOUR CORNERS FRIDAY INTO SATURDAY LEAVING TEMPERATURES FORECAST
BELOW NORMAL...FOR A CHANGE...AS ADDITIONAL TROUGH ENERGY LOADS
UPSTREAM OVER THE PACIFIC NW.
BROAD TROUGHING WILL ENCOMPASS MUCH OF THE CONUS BY SATURDAY AND INTO
NEXT WEEK AS THE HIGHLY AMPLIFIED ROSSBY WAVE PATTERN SENDS RIDGING
WELL UP INTO ALASKA. PACIFIC NW TROUGHING WILL EXPAND ACROSS THE
INTERIOR WEST EARLY NEXT WEEK AIDED BY A VERY COLD AIR AND A
DISPLACED SFC HIGH FROM ALASKA AND NORTHERN CANADA. THIS POTENTLY
COLDER SYSTEM STILL LOOKS TO BE ON THE DRY SIDE. CPC MEDIUM RANGE
OUTLOOK AND WPC EXTENDED MODEL DISCUSSIONS ALL GNLY AGREE ON THE
POTENTIAL FOR BELOW NORMAL TEMPERATURES WITH THE CURRENT CHOICE OF
MODEL SOLNS FALLING MOSTLY TO THE LAST FEW RUNS OF ECMWF AND ITS
ENSEMBLES. BLEND OF THE BEST PERFORMING AND CONSENSUS TEMP
GUIDANCE...WITH A BIT MORE WEIGHT TOWARDS THE ECBC SOLN...RESULTS IN
COLD MORNINGS WITH UPPER 20 TO LOW 40 DEGREE READINGS POSSIBLE OVER
THE LOWER DESERTS. TRENDED TEMPERATURES IN A COOLER DIRECTION FOR
NOW AND WILL CONTINUE TO MONITOR THE POTENTIAL FOR NEAR FREEZING OR
FREEZING TEMPERATURES TO OPEN THE 2015 NEW YEAR.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A TIGHTENING PRESSURE GRADIENT WILL EVENTUALLY ALLOW SFC WINDS TO
MAINTAIN A PREVAILING N/NE TRAJECTORY BY LATER THIS
MORNING...HOWEVER PERIODS OF VARIABLE OR UNUSUAL LIGHT SW COMPONENT
WILL BE COMMON AT THE IMMEDIATE SFC THROUGH THE PHOENIX AREA THIS
MORNING...WITH NE WINDS 1-2K FT ABV THE SFC. A FEW GUSTS OVER 15KT
MAY BE POSSIBLE DURING THE LATE MORNING...HOWEVER A WEAKENING
GRADIENT BY LATE AFTERNOON WILL FORCE A LIGHTER E/NE DRAINAGE WIND.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
A PERIOD OF GUSTY NORTH WINDS LATER THIS MORNING (PARTICULARLY AT
KBLH) WILL BE THE PRIMARY AVIATION CONCERN THROUGH THE NEXT 24
HOURS. WHILE MARGINAL LLWS CONDITIONS MAY BRIEFLY OCCUR THIS
MORNING...VERTICAL MIXING SHOULD ALLOW GUSTS TO REACH THE SFC FAIRLY
RAPIDLY. HOWEVER...THE PRESSURE GRADIENT MAY BEGIN TO WEAKEN
SUBSTANTIALLY THIS AFTERNOON...AND UNCERTAINTY EXISTS AS TO THE
DURATION OF STRONGER GUSTS OVER 25KT. CERTAINLY BY THIS
EVENING...SUSTAINED SFC WINDS WILL FALL BELOW 12KT LEADING TO LITTLE
TO NO IMPACTS HEADING INTO WEDNESDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A SERIES OF WEATHER DISTURBANCES MOVING THROUGH THE GREAT BASIN WILL
ALLOW COOLER AIR AND OCCASIONAL BREEZY CONDITIONS TO FILTER INTO THE
DISTRICT THROUGH THE LATTER HALF OF THE WEEK AND WEEKEND. WHILE A
FEW LIGHT SHOWERS MAY BE POSSIBLE OVER PARTS OF EASTERN ARIZONA
FRIDAY...THE MAJORITY OF THE TIME WILL BE DRY. GIVEN THE COOLER
WEATHER...AFTERNOON HUMIDITY LEVELS WILL ONLY FALL INTO A 20 TO 35
PERCENT RANGE WITH GOOD TO EXCELLENT OVERNIGHT RECOVERY.
OVERALL...THE FIRE DANGER WILL BE MINIMAL DURING THIS PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MCLANE/NOLTE
AVIATION....MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
200 PM PST TUE DEC 23 2014
.SYNOPSIS...
WEAKENING UPPER LEVEL HIGH PRESSURE WILL ALLOW A SLIGHT COOLING ON
WEDNESDAY. SURFACE HIGH PRESSURE OVER NEVADA AND UTAH WILL BRING
LOCALLY STRONG...GUSTY NORTHEAST WINDS TO THE COASTAL SLOPES OF THE
MOUNTAINS AND ADJACENT FOOTHILL AREAS...GRADUALLY DECREASING THIS
AFTERNOON THROUGH LATE TONIGHT. A LOW PRESSURE SYSTEM PASSING BY TO
THE NORTH WILL RESULT IN COOLING AND STRONG GUSTY WEST WINDS FOR THE
MOUNTAINS AND DESERTS LATE WEDNESDAY NIGHT INTO CHRISTMAS DAY...WITH
A SLIGHT CHANCE OF SHOWERS ALONG AND WEST OF THE MOUNTAINS.
CONTINUED COOL CONDITIONS WITH PERIODS OF STRONG GUSTY NORTHEAST
WINDS FOR FRIDAY AND SATURDAY.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH CHRISTMAS)...
SURFACE HIGH PRESSURE OVER THE GREAT BASIN CONTINUES TO BRING
LOCALLY STRONG GUSTY SANTA ANA WINDS TO THE COASTAL SLOPES OF THE
MOUNTAINS AND ADJACENT FOOTHILL AREAS. THE WINDS ARE EXPECTED TO
GRADUALLY SUBSIDE THIS AFTERNOON THROUGH LATE TONIGHT.
A FEW DEGREES OF COOLING IS EXPECTED ALONG AND WEST OF THE MOUNTAINS
FOR WEDNESDAY AS OFFSHORE FLOW WEAKENS AND HIGH PRESSURE ALOFT
WEAKENS. BUFKIT SHOWS LESS MARINE LAYER TONIGHT COMPARED TO THIS
MORNING...BUT ALONG WITH THE HRRR AND THE WRFEMS...AND SUPPORT FROM
THE VISIBLE SATELLITE IMAGERY...THERE COULD BE SOME PATCHY DENSE
FOG. THIS HAS BEEN ADDED TO THE FORECASTS FOR THIS AFTERNOON THROUGH
WEDNESDAY MORNING.
FOR WEDNESDAY NIGHT INTO CHRISTMAS DAY...A TROUGH WILL BRING A
RETURN OF ONSHORE FLOW WITH COOLING AND STRONG GUSTY WEST WINDS FOR
THE MOUNTAINS AND DESERTS FOR LATE WEDNESDAY NIGHT INTO CHRISTMAS
MORNING. A SLIGHT CHANCE OF MAINLY LIGHT SHOWERS ALONG AND WEST OF
THE MOUNTAINS FOR LATE WEDNESDAY NIGHT INTO CHRISTMAS MORNING IS
EXPECTED. A DUSTING OF SNOWFALL IS POSSIBLE IN THE MOUNTAINS...
MAINLY ABOVE 6000 TO 6500 FEET.
&&
.LONG TERM (FRIDAY THROUGH MONDAY)...
CONTINUE COOL FRIDAY THROUGH MONDAY WITH HIGH TEMPERATURES ONLY
AROUND 5 DEGREES BELOW AVERAGE. SURFACE HIGH PRESSURE OVER THE GREAT
BASIN WILL DEVELOP ONCE AGAIN FOR PERIODS OF STRONG GUSTY NORTHEAST
WINDS FRIDAY AND SATURDAY. ANOTHER COLD LOW PRESSURE SYSTEM MOVING
SOUTHWARD THROUGH THE WESTERN STATES FOR SUNDAY THROUGH TUESDAY...AS
SEEN IN THE GFS ENSEMBLE MEAN...COULD BRING A RETURN OF ONSHORE FLOW
EARLY MONDAY WITH A SLIGHT CHANCE OF SHOWERS FOLLOWED BY GUSTY NORTH
TO NORTHEAST WINDS FOR TUESDAY AND WEDNESDAY...AND CONTINUED RATHER
COOL CONDITIONS.
&&
.AVIATION...
232130Z...SKC CONDS WITH P6SM WILL CONTINUE THROUGH WEDNESDAY WITH
THE EXCEPTION OF PATCHY LOW CLOUDS AND FOG FORMING ON THE IMMEDIATE
COASTLINE TONIGHT.
GUSTY NE WINDS WILL CONTINUE THROUGH TONIGHT ALONG THE COASTAL
FOOTHILLS OF SAN DIEGO COUNTY...NORTHWESTERN PORTIONS OF THE INLAND
EMPIRE...AND THE SANTA ANA MOUNTAINS. AREAS OF LLWS AND MOD-STG
UDDFS POSSIBLE OVER AND SW OF THE MTNS...INCLUDING VCNTY KONT AND
KSNA. NE-E WINDS WILL WEAKEN SLIGHTLY WEAKEN BY WEDNESDAY MORNING.
&&
.MARINE...
100 PM...BRIEF PATCHY DENSE FOG MAY OCCUR THIS AFTERNOON THROUGH
TONIGHT OVER THE COASTAL WATERS. A TROUGH OF LOW PRESSURE MOVING
INLAND WED NIGHT INTO THU WILL BRING GUSTY WEST-NORTHWEST WINDS TO
THE COASTAL WATERS. WIND GUSTS OF 20-25 KT ARE LIKELY OVER THE
COASTAL WATERS WED NIGHT INTO THU AFTERNOON. WINDS WILL WEAKEN THU
NIGHT. NO HAZARDOUS MARINE WEATHER FRI-SAT.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE OVER THE GREAT BASIN WILL WEAKEN THROUGH
WEDNESDAY. THIS FEATURE SHALL CONTINUE THE WEAK TO MODERATE OFFSHORE
FLOW AND ABOVE NORMAL HIGH TEMPERATURES WEST OF THE MOUNTAINS. FROM
WEDNESDAY NIGHT INTO THURSDAY MORNING A TROUGH OF LOW PRESSURE WILL
BRING ONSHORE WINDS OF MODERATE STRENGTH...INCREASING RH...LOWER
HIGH TEMPS...AND A SLIGHT CHANCE OF LIGHT RAIN SHOWERS OVER AND WEST
OF THE MOUNTAINS. OFFSHORE FLOW WILL RETURN FRIDAY INTO SATURDAY
WITH TEMPERATURES REMAINING AT OR BELOW NORMAL.
&&
.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY UNTIL 6 PM PST THIS EVENING FOR THE ORANGE COUNTY
COASTAL AREAS...RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO
COUNTY MOUNTAINS...SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE...SAN DIEGO COUNTY MOUNTAINS...
SAN DIEGO COUNTY VALLEYS...SANTA ANA MOUNTAINS AND
FOOTHILLS.
PZ...NONE.
&&
$$
PUBLIC...SMALL
FIRE WEATHER...JT
AVIATION/MARINE...JT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1058 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1055 AM MST TUE DEC 23 2014
UPDATED FOR EXPIRATION OF WINTER STORM WARNING FOR N EL PASO...AND
EXPIRATION OF HIGH WIND WARNING FOR S EL PASO AND PUEBLO COUNTIES.
STRONG NORTHERLY WINDS CONTINUE ACROSS THE PLAINS...BUT ARE
EXPECTED TO WANE THROUGH THE AFTN FROM WEST TO EAST. MOORE
UPDATE ISSUED AT 933 AM MST TUE DEC 23 2014
QUICK UPDATE TO ADJUST CLOUD COVER AND POPS FROM THE EASTERN MTS
WESTWARD. ONGOING FORECAST GRIDS FOR THE E PLAINS LOOK GOOD AT
THIS TIME. MOORE
UPDATE ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1055 AM MST TUE DEC 23 2014
VFR CONDITIONS EXPECTED AT THE THREE MAIN TAF SITES OF KCOS...KPUB
AND KALS FOR THE NEXT 24 HRS. GUSTY NORTH WINDS WILL BE ON THE
WANE FROM WEST TO EAST THROUGH THE AFTN. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MOORE
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
935 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 933 AM MST TUE DEC 23 2014
QUICK UPDATE TO ADJUST CLOUD COVER AND POPS FROM THE EASTERN MTS
WESTWARD. ONGOING FORECAST GRIDS FOR THE E PLAINS LOOK GOOD AT
THIS TIME. MOORE
UPDATE ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MOORE
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
713 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MW
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
431 AM MST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1037 PM EST WED DEC 24 2014
.SYNOPSIS...
STRONG LOW PRESSURE TRACKING ACROSS THE GREAT LAKES WILL BRING
HEAVY RAINFALL AND GUSTY WINDS THROUGH CHRISTMAS. DRY WEATHER
WITH ABOVE NORMAL TEMPERATURES WILL FOLLOW FROM CHRISTMAS
AFTERNOON INTO SATURDAY. A COLD FRONT MAY BRING A FEW RAIN OR
SNOW SHOWERS SUNDAY. ANOTHER STORM MAY AFFECT US LATE MONDAY INTO
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1030 PM UPDATE...
HEAVIER SHOWERS MOVING ALONG THE S COAST AND CAPE/ISLANDS WILL BE
EXITING THE REGION NEXT 1-2 HOURS...OTHERWISE A GENERAL LULL IN
THE RAINFALL ACROSS MUCH OF SNE. HRRR SHOWS REGENERATION OF
RAINFALL ACROSS SNE FROM WEST TO EAST 08-12Z AS COLD FRONT MOVES
ACROSS REGION. FLOOD THREAT IS LOW AT THIS POINT BUT WILL KEEP THE
WATCH UP AS ADDITIONAL RAINFALL EXPECTED AND COULD SEE SOME
HEAVIER DOWNPOURS AND AN ISOLD TSTM ALONG THE FRONT AS SECONDARY
LOW LEVEL JET MOVES INTO THE REGION IN HIGH PWAT AIRMASS. HRRR IS
HINTING AT A FINE LINE DEVELOPING ALONG THE FRONT BUT PROBABLY NOT
UNTIL IT GETS TO OUTER CAPE/ACK OR EVEN OFFSHORE AS BEST
INSTABILITY IS JUST OFFSHORE.
WIND THREAT IS MARGINAL BUT COULD STILL SEE BRIEF GUSTS TO 35-40
KT...PRIMARILY ACROSS SE MA WHERE TEMPS ARE IN THE LOW TO MID 60S
ALLOWING FOR A WEAKENING INVERSION TO POTENTIALLY TAP INTO 50-55
KT 2K FT WINDS. CURRENTLY SEEING GUSTS NEAR 30 KT. FINE LINE STILL
POSSIBLE WHICH WOULD ENHANCE STRONG WIND POTENTIAL BUT IT IS
LOOKING LESS LIKELY FOR SE MA.
AT 02Z...WARM FRONT EXTENDS FROM CENTRAL CT TO JUST S OF BOS.
TEMPS IN THE LOWER 60S TO THE S WITH GUSTY S WINDS...AND IN THE
LOWER 40S TO THE NORTH AND WEST WITH LIGHT N WINDS. USED HI-RES
GUIDANCE FOR TEMPS WHICH HAS WARM FRONT GRADUALLY LIFTING N AND W
ACROSS SNE OVERNIGHT...WITH COOLER AIR HANGING THE LONGEST IN THE
CTY VALLEY. EXPECT TEMPS TO RISE INTO AND THROUGH THE 50S IN THE
INTERIOR OVERNIGHT.
PREVIOUS DISCUSSION...
MODERATE TO HIGH CONFIDENCE...LOWER WITH RESPECT TO WIND
POTENTIAL.
BULK OF PRECIP WILL CONTINUE TO STREAM UP THE COAST WITH
INCREASING PWATS. KEPT PRECIP TOTALS ON ORDER OF 1-2 INCHES...BUT
COULD SEE LOCALLY HIGHER AMOUNTS MAINLY ACROSS NE CT/RI/SE MA.
WARM FRONT APPEARS TO BE SITTING ACROSS S COASTAL AREAS. STILL
HAVING A TOUGH TIME MOVING N WITH LIGHT N-NE WINDS IN PLACE WITH
JUST ENOUGH DRAINAGE AND COLD AIR DAMMING. NOTING PRES FALLS OF
3-4 MB/3 HR /TO 21Z/ WITH FASTEST FALLS ACROSS E NY INTO W VT.
COLD FRONT ACROSS CENTRAL OH/WESTERN WV AND E KY AT 21Z WILL
EVENTUALLY SHIFT E...WHICH SHOULD PUSH THE WARM FRONT NORTHWARD
OVERNIGHT. AS COLD FRONT APPROACHES OVERNIGHT...SOME QUESTION AS
TO WHETHER THERE WILL BE A FINE LINE ASSOCIATED WITH IT. IF THIS
DOES DEVELOP...WILL NEED TO MONITOR FOR BRIEF STRONG WIND GUSTS AS
IT CROSSES THE REGION. ALSO...PRETTY GOOD INSTABILITY STARTING TO
MOVE IN WITH LI/S FROM ZERO TO -2 AND K INDICES IN THE LOWER-MID
30S. MAY SEE ISOLD THUNDERSTORMS DEVELOP AHEAD OF THE COLD FRONT
OVERNIGHT.
STRONG INFLUX OF MILDER TEMPS MOVE IN WITH THE WARM FRONT
PASSAGE...SO TEMPS TO RISE THROUGH THE NIGHT INTO THE 50S...AND
POSSIBLY TO THE LOWER 60S ACROSS PORTIONS OF E MA BEFORE SUNRISE.
THIS WILL APPROACH RECORD LEVELS /SEE LISTING IN CLIMATE SECTION
BELOW/.
STILL SOME QUESTION AS TO HOW MUCH WIND WILL MIX DOWN. NOTING
LITTLE IF ANY MIXING BELOW 900 HPA SO WILL BE TOUGH TO MIX DOWN
THE STRONG JET ASSOCIATED WITH THIS SYSTEM...ON ORDER OF 50-60 KT
AT H9 AND H85. IF FINE LINE MENTIONED ABOVE DOES MATERIALIZE...
MIGHT SEE IT. SOMETHING TO MONITOR CLOSELY. FOR NOW...HAVE
MENTIONED WIND GUSTS UP TO 30-35 KT FOR MOST AREAS...AND COULD
REACH AROUND 40 KT ACROSS RI/SE MA WHERE SOME MIXING WILL START TO
WORK IN AHEAD OF COLD FRONT AFTER MIDNIGHT AS THE CORE OF THE 900
AND 850 HPA JETS MOVE ACROSS EASTERN AREAS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
CHRISTMAS DAY...HIGH CONFIDENCE.
SHORT RANGE MODELS IN VERY GOOD AGREEMENT IN PUSHING FRONT
OFFSHORE BY MID MORNING WITH LEFTOVER SHOWERS MOVING OFFSHORE AS
DRY SLOT WORKS IN. WINDS SHIFT TO W-SW WITH DRIER AIR WORKING IN.
LAPSE RATES STEEPEN ESPECIALLY FROM 900 HPA AND BELOW WHICH WILL
ALLOW GOOD MIXING TO WORK IN. QUESTION IS HOW STRONG WILL THE
GUSTS BE. AT THIS POINT...CONTINUED TO SEE WIND GUSTS JUST BELOW
WIND ADVISORY CRITERIA...THOUGH COULD BE SOME MARGINAL GUSTS TO
CRITERIA MAINLY ALONG THE S COAST...CAPE COD AND THE ISLANDS THU
AFTERNOON. MIGHT ALSO SEE SOME HIGHER GUSTS ACROSS THE HIGHER
INLAND TERRAIN OF THE WORCESTER HILLS AND MONADNOCKS AS WELL AS
THE E SLOPES OF THE BERKSHIRES. KEPT ADVISORY THROUGH LATE MORNING
ACROSS RI/SE MA...BUT MAY NEED TO EXTEND INTO THE AFTERNOON.
WITH GENERAL OVERALL MID LEVEL STEERING CURRENTS FROM W-E...NOT
MUCH COLD AIR TO TRANSPORT INTO THE REGION. TEMPS WILL HOLD IN THE
50S DURING THE MORNING BEFORE STARTING TO SLOWLY FALL BACK THU
AFTERNOON WITH THE INCREASING WIND.
CHRISTMAS NIGHT...HIGH CONFIDENCE.
HIGH PRES RIDGE BEGINS TO BUILD E OUT OF THE APPALACHIANS. WINDS
WILL SHIFT TO W-NW. WINDS WILL REMAIN GUSTY EARLY THU NIGHT...THEN
WILL DIMINISH OVERNIGHT WITH DRY CONDITIONS. COLDER AIR REMAINS N
OF THE REGION. WITH GENERALLY MOSTLY CLEAR SKIES IN PLACE...THOUGH
SOME CLOUDS LINGER ACROSS NW MA...TEMPS WILL FALL BACK TO THE
UPPER 20S ACROSS N CENTRAL AND W MA TO THE UPPER 30S ON THE OUTER
CAPE AND NANTUCKET. THESE READINGS ARE AROUND 10 DEGREES ABOVE
SEASONAL NORMALS FOR LATE DECEMBER.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
* CLEARING...WINDY AND MILD CHRISTMAS DAY.
* REMAINING DRY WITH ABOVE NORMAL TEMPERATURES FRI AND SAT.
* POTENTIAL FOR SOME RAIN OR SNOW EARLY NEXT WEEK.
FRIDAY AND SATURDAY...HIGH CONFIDENCE.
HIGH PRESSURE BUILDS TO THE MID ATLANTIC COAST. DRY WEATHER WILL
PREVAIL WITH LIGHTER WINDS. TEMPERATURES WILL REMAIN ABOVE AVERAGE
WITH HIGHS IN 40S BOTH DAYS AND LOWS MAINLY IN 30S.
SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE.
MODELS DROP A WEAK COLD FRONT THROUGH SOUTHERN NEW ENGLAND SUNDAY.
MOISTURE APPEARS TO BE LIMITED AND CONVERGENCE RATHER WEAK...SO
ONLY EXPECTING WIDELY SCATTERED RAIN SHOWERS AS IT MOVES THROUGH.
TEMPERATURE PROFILES MAY BE COLD ENOUGH FOR SOME WET SNOW TO MIX
IN ACROSS HIGHER TERRAIN IN WESTERN MA.
24/12Z MODELS CONTINUE TO STRUGGLE WITH THE DETAILS OF THE
SYNOPTIC PATTERN NEXT WEEK. THERE ARE SOME SIGNS THE SOLUTIONS ARE
STARTING TO CONVERGE...WITH THE 12Z ECMWF COMING INTO LINE WITH
THE 12Z GFS. THAT SAID...ENSEMBLES STILL SHOWING 100-140 DAM SPREAD
IN THE 500 MB HEIGHTS...WHICH DOES NOT INSPIRE MUCH CONFIDENCE IN
THE FORECAST DETAILS.
LATEST DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE ESTABLISH A FAIRLY
ZONAL FLOW INTO SOUTHERN NEW ENGLAND MONDAY INTO WEDNESDAY. THIS
WOULD STEER ANY STORMS EITHER TO OUR NORTH...OR TOO OUR SOUTH...
DEPENDING ON WHERE IT ORIGINATED.
LEANED TOWARD A CONSENSUS MODEL BLEND TO HELP IRON OUT THESE
DIFFERENCES FOR NOW. THIS WOULD BRING A CHANCE FOR PRECIPITATION
TO SOUTHERN NEW ENGLAND DURING THIS TIME PERIOD. THERMAL PROFILES
SUGGEST THE POSSIBILITY FOR LIGHT SNOW ACROSS MUCH OF SOUTHERN NEW
ENGLAND...WITH RAIN MORE LIKELY CLOSER TO THE SOUTH COAST.
THIS IS SEVERAL DAYS AWAY...WITH LOW CONFIDENCE IN THE DETAILS. LOW
LEVEL TEMPERATURES LOOK A BIT WARM FOR ANY SIGNIFICANT
ACCUMULATIONS...ESPECIALLY FROM THE MASS PIKE TO THE SOUTH COAST.
WE NEED TO SEE HOW LARGER SCALE FEATURES WILL BE RESOLVED OVER THE
NEXT FEW DAYS.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE. EXPECTING WIDESPREAD IFR/LIFR
CONDITIONS IN RAIN...HEAVY AT TIMES...ALONG WITH ISOLD TSTMS.
VSBYS IMPROVE TO MVFR-LOW END VFR IN HEAVIER RAIN MAINLY AFTER
MIDNIGHT. CIGS MAY IMPROVE ACROSS CT VALLEY AFTER 09Z AS RAIN
BEGINS TO SHIFT E. S-SE SURFACE WIND GUSTS UP TO 25-30 KT. LLWS ON
S WINDS AT 40-60 KT AT 2 KFT. ANY TSTM MAY CAUSE BRIEF WIND GUSTS
UP TO 40 KT...GREATEST RISK ACROSS RI/SE MA LATE TONIGHT.
THURSDAY...MODERATE CONFIDENCE.
IFR-LIFR CIGS/MVFR-VFR VSBYS IMPROVE TO VFR FROM W-E AS RAIN
MOVES OFFSHORE. SW WINDS GUSTING UP TO 25-30 KT...SHIFTING TO W
BY MIDDAY. LOW CHANCE FOR GUSTS UP TO 40 KT ACROSS THE HIGHER
INTERIOR TERRAIN.
THURSDAY NIGHT...HIGH CONFIDENCE.
VFR. W WINDS GUSTING TO 25-30 KT EARLY...HIGHEST ALONG COAST...
THEN DIMINISHING AFTER MIDNIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF TRENDS. MODERATE CONFIDENCE
IN TIMING A WARM FRONT TO MOVE NORTH OF THE TERMINAL THIS
EVENING.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY AND SATURDAY...HIGH CONFIDENCE VFR.
SUNDAY...MODERATE CONFIDENCE. MVFR POSSIBLE IN ISOLATED RAIN
SHOWERS.
MONDAY...MODERATE CONFIDENCE. MAINLY VFR. LOWER CONDITIONS SOUTH
OF NEW ENGLAND. LOW PROBABILITY THESE LOWER CONDITIONS MOVE
FARTHER NORTH INTO SOUTHERN NEW ENGLAND.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...STRONG S-SE LOW LEVEL JET PASSES ACROSS THE WATERS
THROUGH TONIGHT. LOW LEVEL INVERSION IN PLACE THROUGH 900 HPA SO
WILL BE TOUGH TO MIX THE BULK DOWN. WILL SEE GUSTS UP TO 25-30 KT
ON THE OUTER WATERS...INCREASING TO 35 KT S AND E OF NANTUCKET
TOWARD DAYBREAK. HAVE ISSUED GALES FOR THE OUTER WATERS. MARGINAL
CONDITIONS FOR GALES ON NARRAGANSETT BAY SO BACKED OFF THE STRONG
SMALL CRAFT. VSBYS REDUCED IN PATCHY FOG AND RAIN. ISOLD TSTMS
POSSIBLE OVERNIGHT.
THURSDAY...COLD FRONT MOVES OFFSHORE BY MIDDAY. WINDS SHIFT TO
W-SW AND INCREASE...GUSTS UP TO 40 KT ON THE OUTER WATERS. HAVE
CONVERTED GALE WATCHES FOR SOUTHERN BAYS AND SOUNDS TO WARNINGS
WITH GUSTS TO 35 KT. REMAINING WATERS HAVE SMALL CRAFTS.
THURSDAY NIGHT...GALE FORCE W WINDS EARLY THU NIGHT WILL DIMINISH
TO SMALL CRAFT CRITERIA OVERNIGHT. SMALL CRAFT WINDS ON BOSTON
HARBOR/NARRAGANSETT BAY WILL DIMINISH OVERNIGHT.
OUTLOOK...FRIDAY THROUGH MONDAY...MODERATE CONFIDENCE.
WINDS GRADUALLY DIMINISH FRIDAY...WITH SEAS ALSO SLOWLY SUBSIDING
INTO SATURDAY AS A HIGH PRESSURE BUILDS OVER THE MID ATLANTIC
STATES. A WEAKENING COLD FRONT MAY BRING AN ISOLATED SHOWER OR TWO
AS IT DROPS THROUGH NEW ENGLAND SUNDAY. WINDS AND SEAS SHOULD
REMAIN BELOW SMALL CRAFT ADVISORY LEVELS ACROSS ALL BUT THE
OUTERMOST COASTAL WATERS FROM MIDDAY SATURDAY INTO MONDAY.
MODERATE PROBABILITY OF 5 FOOT SEAS ACROSS THE OUTERMOST COASTAL
WATERS...PARTICULARLY SOUTH AND EAST OF NANTUCKET.
&&
.CLIMATE...
RECORD HIGHS FOR TODAY / CHRISTMAS DAY
BOS...61 IN 1996 / 65 IN 1889
PVD...60 IN 1990 / 63 IN 1964
BDL...59 IN 1996 / 64 IN 1964
ORH...57 IN 1996 / 60 IN 1964
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004.
MA...FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ002>022-026.
WIND ADVISORY UNTIL 7 AM EST THURSDAY FOR MAZ013-016>021.
WIND ADVISORY FROM 1 AM TO 9 AM EST THURSDAY FOR MAZ022>024.
RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007.
WIND ADVISORY UNTIL 7 AM EST THURSDAY FOR RIZ002-004-005-007.
MARINE...GALE WARNING FROM 10 AM TO 9 PM EST THURSDAY FOR ANZ232>234.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST THURSDAY NIGHT FOR
ANZ230.
SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR ANZ231.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST THURSDAY NIGHT FOR
ANZ236.
GALE WARNING FROM 9 AM TO 9 PM EST THURSDAY FOR ANZ235-237.
GALE WARNING FROM 9 AM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT
FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ251.
GALE WARNING FROM 6 AM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT
FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...KJC
SHORT TERM...EVT
LONG TERM...BELK
AVIATION...BELK/EVT
MARINE...BELK/EVT
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
928 PM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE STRENGTHENS AS IT LIFTS UP ACROSS THE GREAT LAKES
REGION INTO CANADA THROUGH TONIGHT. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS OUR AREA EARLY THURSDAY MORNING. HIGH PRESSURE WILL
THEN SETTLE TO OUR SOUTH THURSDAY NIGHT AND FRIDAY, BEFORE SHIFTING
OFFSHORE INTO SATURDAY. A COLD FRONT IS FORECAST TO SETTLE THROUGH
OUR AREA SUNDAY, HOWEVER IT MAY THEN STALL NEARBY. LOW PRESSURE
SHOULD DEVELOP AND MOVE ALONG THIS FRONT SUNDAY NIGHT AND MONDAY,
TRACKING TO OUR SOUTH. HIGH PRESSURE NEAR THE CENTRAL PLAINS THEN
STARTS TO GRADUALLY BUILD TOWARD THE MID ATLANTIC TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WARM FRONT CONTINUES TO MAKE SLOW PROGRESS NORTH THROUGH THE REGION.
THE BIG STORY WILL BE THE COLD FRONT WHICH IS EXPECTED TO SWEEP
THROUGH THE REGION DURING THE VERY EARLY MORNING HOURS.
SHOULD CONTINUE TO SEE LIGHT TO MODERATE RAIN THROUGH THIS EVENING,
THEN AS THE FRONT APPROACHES, THE COMBINATION OF MODEST ELEVATED
INSTABILITY (ELEVATED CAPE VALUES AROUND 100 J/KG) AND VERY LARGE
SHEAR VALUES LEADS TO AN INCREASED CHANCE FOR ISOLATED
THUNDERSTORMS. GIVEN THE LARGE SHEAR VALUES, COULD SEE GUSTY WINDS
WITH ANY THUNDERSTORMS.
RADAR CONTINUES TO SHOW LULL IN PRECIP, THOUGH HRRR WANTS TO
REDEVELOP AROUND MIDNIGHT. WILL LOWER POPS OVER THE NEXT FEW HOURS
BEFORE RAMPING UP AGAIN. PRECIP SHOULD INCREASE WITH THE FROPA, IF
NOT BEFORE.
BEHIND THE COLD FRONT, THE RAIN SHOULD CLEAR OUT QUICKLY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
FOR CHRISTMAS DAY, WE KEEP A RATHER TIGHT PRESSURE GRADIENT OVER THE
REGION LEADING TO BREEZY CONDITIONS THROUGH THE DAY TIME HOURS.
HOWEVER, WITH THE CONTINUED DRY AIR ADVECTION, SHOULD SEE MOSTLY DRY
CONDITIONS EXCEPT NEAR THE COAST WHERE RAIN MAY LINGER THROUGH MID
MORNING. DEPENDING ON HOW QUICKLY THE INVERSION BREAKS, COULD EVEN
SEE CLOUDS RAPIDLY DISSIPATING THROUGH THE MORNING.
THE TEMPERATURE GRADIENT ACROSS THE COLD FRONT IS SOMEWHAT MODEST.
THEREFORE, EXPECT HIGHS TOMORROW TO BE 5 TO 10 DEGREES ABOVE NORMAL
(RANGING FROM THE LOWER 40S TO LOWER 50S), A FAR CRY FROM THE UPPER
60S THAT DELMARVA HAS THIS AFTERNOON, BUT STILL QUITE A WARM
CHRISTMAS DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH LIFTING OUT
OF NEW ENGLAND THURSDAY NIGHT AS ENERGY RELOADS ACROSS THE WEST AND
CENTRAL PLAINS. THIS ENERGY WILL AMPLIFY A TROUGH WELL TO OUR WEST
FRIDAY THROUGH SUNDAY. THE INITIAL ENERGY EJECTS NORTHEASTWARD
BETWEEN A RIDGE OFF THE SOUTHEASTERN U.S. COAST AND BUSIER FLOW
ACROSS CANADA. THIS SETUP HAS THE POTENTIAL TO BE AN OVERRUNNING
EVENT LATE SUNDAY AND MONDAY FOLLOWING A SECONDARY COLD FRONTAL
PASSAGE. THESE TYPES OF SETUPS ESPECIALLY FARTHER OUT IN TIME CARRY
MORE UNCERTAINTY AS THE TIMING AND TRACK OF THE ENERGY AND
ASSOCIATED SURFACE LOW EJECTING NORTHEASTWARD ARE KEY. AS ENERGY
CONTINUES TO DIVE INTO THE WEST AND PLAINS, THE TROUGH CONTINUES TO
EXPAND EASTWARD AND THIS APPEARS TO BE THE START OF A TURN TO COLDER
WEATHER IN THE EAST. WE USED A MODEL BLEND APPROACH FOR THURSDAY
NIGHT THROUGH SATURDAY, THEN WENT WITH THE 12Z WPC GUIDANCE
THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL
COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR THURSDAY NIGHT...HIGH PRESSURE IS FORECAST TO BUILD INTO OUR
AREA FROM THE SOUTHWEST. THIS WILL ALLOW THE PRESSURE GRADIENT TO
RELAX AND AS THE CAA WANES WITH EVEN SOME MODERATION AT 850 MB, THE
MIXING WILL WEAKEN AND THUS THE WINDS ARE EXPECTED TO DIMINISH
FAIRLY QUICKLY DURING THE EVENING. THIS WILL SET THE STAGE FOR A
COLDER NIGHT.
FOR FRIDAY AND SATURDAY...THE CENTER OF HIGH PRESSURE SLIDES TO OUR
SOUTH FRIDAY AND THEN OFFSHORE INTO SATURDAY. AS THIS OCCURS, SOME
RIDGING ALOFT IS FORECAST TO BUILD ACROSS THE EAST DOWNSTREAM OF AN
AMPLIFYING TROUGH ACROSS THE WEST AND INTO THE PLAINS. THIS IS
DIVIDED BY A COLD FRONT THAT IS FORECAST TO BE APPROACHING OUR AREA
SATURDAY NIGHT. THIS FRONT MAY NOT HAVE MUCH IN THE WAY OF MOISTURE
WITH IT AS THE MAIN SURFACE LOW TRACKS FAR TO OUR NORTH. OVERALL, A
DRY AND MILD TIME FRAME WITH PERHAPS SOME INCREASE IN CLOUDS LATE
SATURDAY.
FOR SUNDAY AND MONDAY...THE POTENTIAL REMAINS FOR AN OVERRUNNING
SETUP. THIS IS DUE TO THE MAIN UPPER-LEVEL TROUGH SITTING BACK WELL
TO OUR WEST WITH THE EAST UNDER MORE OF A SOUTHWESTERLY FLOW ALOFT
BETWEEN THE SOUTHEASTERN RIDGE AND THE MORE BUSY FLOW ACROSS CANADA.
THE FORECAST CHALLENGE IS A SURFACE LOW THAT DEVELOPS OUT OF THE
MAIN TROUGH THEN IS EJECTED NORTHEASTWARD ALONG A STALLED FRONTAL
BOUNDARY. WHILE THE SIGNAL IS THERE FOR AN OVERRUNNING EVENT, THE
TRACK AND ASSOCIATED PRECIPITATION SHIELD IS LESS CERTAIN. OF COURSE
THE TRACK WILL ALSO DETERMINE THE THERMAL PROFILES AS WELL, PLUS A
BUILDING SURFACE HIGH TO THE NORTH COULD COMPLICATE THINGS SOME. WE
FAVORED MORE OF THE WPC GUIDANCE DUE TO UNCERTAINTY IN THE
TRACK/DETAILS. THIS RESULTS IN AN AREA OF LOW LIKELY POPS ACROSS THE
SOUTHERN AREAS LATER SUNDAY WHERE THERE IS ENOUGH CONSENSUS, AND
ALSO TO PRESERVE SOME CONTINUITY. THE POPS THEN DECREASE SOME
NORTHWARD. THERE IS THE POTENTIAL FOR SOME SNOW ON THE NORTHERN
PORTION OF THE PRECIPITATION SHIELD, HOWEVER ANY AMOUNTS AND
ASSOCIATED THERMAL PROFILES WILL BE DETERMINED BY THE TRACK OF THE
SURFACE FEATURE GIVEN MOSTLY AN OVERRUNNING SCENARIO. THERE IS A CHC
THIS FEATURE TRACKS EVEN FARTHER SOUTH IF HIGH PRESSURE TO THE NORTH
IS STRONGER WITH ITS SOUTHWARD PUSH.
FOR TUESDAY AND WEDNESDAY...IT APPEARS ADDITIONAL ENERGY WILL BE
EJECTING NORTHEASTWARD AND WHILE THE EARLIER SURFACE LOW SHOULD BE
GONE TO START, A FRONTAL BOUNDARY MAY LINGER NEARBY TUESDAY. AS THE
UPPER-LEVEL TROUGH MIGRATES EAST SOME, THERE COULD BE SOME ENERGY
STILL SLIDING NORTHEASTWARD ALONG THE FRONT. AS OF NOW, WE FAVORED
MORE OF THE WPC GUIDANCE WHICH INDICATES A COLD FRONT SHIFTING
EAST TUESDAY AS STRONG HIGH PRESSURE BUILDS TOWARD THE CENTRAL
PLAINS AND ALSO EXPANDS TOWARD THE MID ATLANTIC INTO WEDNESDAY. THIS
RESULTS IN COLDER AIR SEEPING SOUTH AND EASTWARD.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS WILL PERSIST IN OUR REGION INTO TONIGHT. CONDS HAVE
BEEN VARIABLE FROM LIFR TO MVFR. THERE HAS BEEN A LULL IN THE PRECIP
IN THE NEAR TERM AND THIS SHOULD CONTINUE THRU THE EVE.
UNFORTUNATELY, IN SOME OF THESE AREAS, VSBYS HAVE DROPPED QUITE A
BIT, BUT FOR NOW THESE DROPS DON`T SEEM TO LAST ALL THAT LONG.
THEREFORE, WILL KEEP PREVAILING IFR CONDITIONS. THIS EVENING AND
LATE TONIGHT COULD ALSO SEE ISOLATED TSRA. WITH ANY TSRA COULD SEE
VRB AND GUSTY WINDS. HOWEVER, COVERAGE IS TOO LIMITED TO INCLUDE
IN THE TAFS AT THIS TIME.
A LOW LEVEL SOUTHERLY JET AS DEPICTED BY THE VAD WIND PROFILE FROM
KDIX CONTINUES OVER THE COASTAL PLAIN AND SHOULD PERSIST THROUGH AT
LEAST 06Z. AS A RESULT, WE HAVE CONTINUED THE MENTION OF LOW LEVEL WIND
SHEAR AT KTTN, KPNE, KPHL, KILG, KMIV AND KACY. BOTH KRDG AND KABE
SHOULD BE ENOUGH WEST OF THE LOW LEVEL JET.
AT THE SURFACE, GENERALLY LIGHT SOUTHERLY WINDS WILL CONTINUE UNTIL
THE COLD FRONT ARRIVES. THE COLD FRONT AND ASSOCIATED ABRUPT SHIFT
TO WESTERLY WINDS IS EXPECTED TO ARRIVE BETWEEN 06 AND 09Z. BEHIND
THE FRONT, EXPECT CONDITIONS TO IMPROVE TO MVFR, THEN VFR.
OUTLOOK...
THURSDAY NIGHT...VFR. WEST-NORTHWEST WINDS 10-15 KNOTS EARLY,
DIMINISHING TO LESS THAN 10 KNOTS.
FRIDAY AND SATURDAY...VFR, ALTHOUGH CLOUDS MAY INCREASE LATE
SATURDAY AS A COLD FRONT APPROACHES. SOUTHWEST WINDS MAINLY AROUND
10 KNOTS.
SUNDAY AND MONDAY...CLOUDS POTENTIALLY LOWER TO SUB-VFR AS A SYSTEM
TRACKS TO OUR SOUTH. THIS COULD RESULT IN SOME RAIN OR SNOW, HOWEVER
CONFIDENCE IS ON THE LOW SIDE. WINDS SHOULD TURN NORTHERLY.
&&
.MARINE...
SOUTHERLY WINDS WILL BE INCREASING SHORTLY, AND SHOULD SEE GUSTS
ABOVE 25KT ON ALL THE WATERS THROUGH THE EVENING HOURS. WITH THE
INCREASING WINDS, SEAS SHOULD ALSO BUILD BACK ABOVE 5 FT. AFTER
MIDNIGHT TONIGHT, LIKELY BETWEEN 2 AND 6 AM LST, A COLD FRONT WILL
PUSH THROUGH, BRINGING AN ABRUPT SHIFT TO WESTERLY WINDS. IN
ADDITION, COULD SEE ISOLATED THUNDERSTORMS WITH THE FRONT. UNDER ANY
THUNDERSTORMS, EXPECT VERY GUSTY WINDS. THE STRONG WESTERLY WINDS
WILL CONTINUE ON ALL THE WATERS THROUGH THE DAY TOMORROW. ALONG THE
OCEAN WATERS, ESPECIALLY THE NORTHERN NEW JERSEY COASTAL WATERS,
COULD SEE A FEW GUSTS ABOVE 30KT. HOWEVER, VERY UNCERTAIN IF WE WILL
REACH GALE FORCE GUSTS. THEREFORE, HAVE CANCELED THE GALE WATCH,
BUT AN SCA IS IN EFFECT FOR ALL THE WATERS THROUGH EARLY TOMORROW
EVENING. HOWEVER, WILL MONITOR WHEN THE NEW GUIDANCE COMES IN THIS
EVENING TO SEE IF THE THREAT FOR GALES FOR TOMORROW CHANGES.
OUTLOOK...
THURSDAY NIGHT...AS THE PRESSURE GRADIENT RELAXES, THE WINDS WILL AS
WELL. IT APPEARS THAT THE WINDS AND SEAS DECREASE FAIRLY QUICKLY,
THEREFORE A SMALL CRAFT ADVISORY WAS NOT EXTENDED AS OF NOW.
FRIDAY AND SATURDAY...THE CONDITIONS SHOULD BE BELOW SMALL CRAFT
ADVISORY CRITERIA AS HIGH PRESSURE BUILDS TO OUR SOUTH AND THEN
OFFSHORE. A WEAK COLD FRONT APPROACHES SATURDAY NIGHT.
SUNDAY AND MONDAY...A COLD FRONT SETTLES SOUTHEASTWARD ACROSS THE
AREA SUNDAY BUT THEN MAY STALL NEARBY. THE SOUTHWESTERLY FLOW MAY
INCREASE SOME AHEAD OF IT, THEN TURN NORTHWESTERLY IN ITS WAKE.
OVERALL, IT APPEARS THAT THE CONDITIONS REMAIN BELOW ADVISORY
CRITERIA. A WEAK LOW PRESSURE SYSTEM SHOULD DEVELOP ON THE FRONT AND
TRACK TO OUR SOUTH DURING THIS TIME FRAME.
&&
.TIDES/COASTAL FLOODING...
THIS EVENING`S COASTAL FLOOD ADVISORY HAS BEEN LOWERED AS IT
APPEARS NOBODY ON CHESAPEAKE BAY HAS HIT TIDAL FLOODING CRITERIA.
TO A LESSER EXTENT THERE IS A SMALL THREAT AGAIN TOMORROW MORNING
ALONG THE CHESAPEAKE. IT LOOKS LIKE WE SHOULD HAVE THE SHIFT TO
WESTERLY WINDS WELL BEFORE THE HIGH TIDE CYCLE, AND THE ASTRONOMICAL
TIDE IS LOWER, SO THE THREAT IS TOO LOW TO MENTION IN THE HWO FOR
NOW, BUT WILL CONTINUE TO MONITOR.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 4 AM EST THURSDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...JOHNSON/NIERENBERG
SHORT TERM...JOHNSON
LONG TERM...GORSE
AVIATION...GORSE/JOHNSON/NIERENBERG
MARINE...GORSE/JOHNSON
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
642 PM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE STRENGTHENS AS IT LIFTS UP ACROSS THE GREAT LAKES
REGION INTO CANADA THROUGH TONIGHT. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS OUR AREA EARLY THURSDAY MORNING. HIGH PRESSURE WILL
THEN SETTLE TO OUR SOUTH THURSDAY NIGHT AND FRIDAY, BEFORE SHIFTING
OFFSHORE INTO SATURDAY. A COLD FRONT IS FORECAST TO SETTLE THROUGH
OUR AREA SUNDAY, HOWEVER IT MAY THEN STALL NEARBY. LOW PRESSURE
SHOULD DEVELOP AND MOVE ALONG THIS FRONT SUNDAY NIGHT AND MONDAY,
TRACKING TO OUR SOUTH. HIGH PRESSURE NEAR THE CENTRAL PLAINS THEN
STARTS TO GRADUALLY BUILD TOWARD THE MID ATLANTIC TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WARM FRONT CONTINUES TO MAKE SLOW PROGRESS NORTH THROUGH THE REGION.
THE BIG STORY WILL BE THE COLD FRONT WHICH IS EXPECTED TO SWEEP
THROUGH THE REGION DURING THE VERY EARLY MORNING HOURS.
SHOULD CONTINUE TO SEE LIGHT TO MODERATE RAIN THROUGH THIS EVENING,
THEN AS THE FRONT APPROACHES, THE COMBINATION OF MODEST ELEVATED
INSTABILITY (ELEVATED CAPE VALUES AROUND 100 J/KG) AND VERY LARGE
SHEAR VALUES LEADS TO AN INCREASED CHANCE FOR ISOLATED
THUNDERSTORMS. GIVEN THE LARGE SHEAR VALUES, COULD SEE GUSTY WINDS
WITH ANY THUNDERSTORMS.
APPEARS TO BE A LULL IN THE PRECIP FOR A T LEAST THE NEXT LITTLE
WHILE AND HAVE ADJUSTED POPS DOWN ACCORDINGLY. HRRR SAYS PRECIP
SHOULD RAMP BACK UP IN A FEW HOURS. WE`LL SEE. ALSO HAVE ADJUSTED
TEMPS, BUT WITH THE WARM FRONT BISECTING THE AREA AND LIGHT RAIN
VERSUS NO RAIN IN SOME SPOTS, TEMPS ARE DIFFICULT EARLY THIS EVE.
ALSO WATCHING FOG AS AREAS WHERE RAIN HAS STOPPED HAS SEEN VSBYS
GO DOWN, BUT FOR NOW THEY DON`T APPEAR TO BE LASTING LONG.
BEHIND THE COLD FRONT, THE RAIN SHOULD CLEAR OUT QUICKLY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
FOR CHRISTMAS DAY, WE KEEP A RATHER TIGHT PRESSURE GRADIENT OVER THE
REGION LEADING TO BREEZY CONDITIONS THROUGH THE DAY TIME HOURS.
HOWEVER, WITH THE CONTINUED DRY AIR ADVECTION, SHOULD SEE MOSTLY DRY
CONDITIONS EXCEPT NEAR THE COAST WHERE RAIN MAY LINGER THROUGH MID
MORNING. DEPENDING ON HOW QUICKLY THE INVERSION BREAKS, COULD EVEN
SEE CLOUDS RAPIDLY DISSIPATING THROUGH THE MORNING.
THE TEMPERATURE GRADIENT ACROSS THE COLD FRONT IS SOMEWHAT MODEST.
THEREFORE, EXPECT HIGHS TOMORROW TO BE 5 TO 10 DEGREES ABOVE NORMAL
(RANGING FROM THE LOWER 40S TO LOWER 50S), A FAR CRY FROM THE UPPER
60S THAT DELMARVA HAS THIS AFTERNOON, BUT STILL QUITE A WARM
CHRISTMAS DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH LIFTING OUT
OF NEW ENGLAND THURSDAY NIGHT AS ENERGY RELOADS ACROSS THE WEST AND
CENTRAL PLAINS. THIS ENERGY WILL AMPLIFY A TROUGH WELL TO OUR WEST
FRIDAY THROUGH SUNDAY. THE INITIAL ENERGY EJECTS NORTHEASTWARD
BETWEEN A RIDGE OFF THE SOUTHEASTERN U.S. COAST AND BUSIER FLOW
ACROSS CANADA. THIS SETUP HAS THE POTENTIAL TO BE AN OVERRUNNING
EVENT LATE SUNDAY AND MONDAY FOLLOWING A SECONDARY COLD FRONTAL
PASSAGE. THESE TYPES OF SETUPS ESPECIALLY FARTHER OUT IN TIME CARRY
MORE UNCERTAINTY AS THE TIMING AND TRACK OF THE ENERGY AND
ASSOCIATED SURFACE LOW EJECTING NORTHEASTWARD ARE KEY. AS ENERGY
CONTINUES TO DIVE INTO THE WEST AND PLAINS, THE TROUGH CONTINUES TO
EXPAND EASTWARD AND THIS APPEARS TO BE THE START OF A TURN TO COLDER
WEATHER IN THE EAST. WE USED A MODEL BLEND APPROACH FOR THURSDAY
NIGHT THROUGH SATURDAY, THEN WENT WITH THE 12Z WPC GUIDANCE
THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL
COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR THURSDAY NIGHT...HIGH PRESSURE IS FORECAST TO BUILD INTO OUR
AREA FROM THE SOUTHWEST. THIS WILL ALLOW THE PRESSURE GRADIENT TO
RELAX AND AS THE CAA WANES WITH EVEN SOME MODERATION AT 850 MB, THE
MIXING WILL WEAKEN AND THUS THE WINDS ARE EXPECTED TO DIMINISH
FAIRLY QUICKLY DURING THE EVENING. THIS WILL SET THE STAGE FOR A
COLDER NIGHT.
FOR FRIDAY AND SATURDAY...THE CENTER OF HIGH PRESSURE SLIDES TO OUR
SOUTH FRIDAY AND THEN OFFSHORE INTO SATURDAY. AS THIS OCCURS, SOME
RIDGING ALOFT IS FORECAST TO BUILD ACROSS THE EAST DOWNSTREAM OF AN
AMPLIFYING TROUGH ACROSS THE WEST AND INTO THE PLAINS. THIS IS
DIVIDED BY A COLD FRONT THAT IS FORECAST TO BE APPROACHING OUR AREA
SATURDAY NIGHT. THIS FRONT MAY NOT HAVE MUCH IN THE WAY OF MOISTURE
WITH IT AS THE MAIN SURFACE LOW TRACKS FAR TO OUR NORTH. OVERALL, A
DRY AND MILD TIME FRAME WITH PERHAPS SOME INCREASE IN CLOUDS LATE
SATURDAY.
FOR SUNDAY AND MONDAY...THE POTENTIAL REMAINS FOR AN OVERRUNNING
SETUP. THIS IS DUE TO THE MAIN UPPER-LEVEL TROUGH SITTING BACK WELL
TO OUR WEST WITH THE EAST UNDER MORE OF A SOUTHWESTERLY FLOW ALOFT
BETWEEN THE SOUTHEASTERN RIDGE AND THE MORE BUSY FLOW ACROSS CANADA.
THE FORECAST CHALLENGE IS A SURFACE LOW THAT DEVELOPS OUT OF THE
MAIN TROUGH THEN IS EJECTED NORTHEASTWARD ALONG A STALLED FRONTAL
BOUNDARY. WHILE THE SIGNAL IS THERE FOR AN OVERRUNNING EVENT, THE
TRACK AND ASSOCIATED PRECIPITATION SHIELD IS LESS CERTAIN. OF COURSE
THE TRACK WILL ALSO DETERMINE THE THERMAL PROFILES AS WELL, PLUS A
BUILDING SURFACE HIGH TO THE NORTH COULD COMPLICATE THINGS SOME. WE
FAVORED MORE OF THE WPC GUIDANCE DUE TO UNCERTAINTY IN THE
TRACK/DETAILS. THIS RESULTS IN AN AREA OF LOW LIKELY POPS ACROSS THE
SOUTHERN AREAS LATER SUNDAY WHERE THERE IS ENOUGH CONSENSUS, AND
ALSO TO PRESERVE SOME CONTINUITY. THE POPS THEN DECREASE SOME
NORTHWARD. THERE IS THE POTENTIAL FOR SOME SNOW ON THE NORTHERN
PORTION OF THE PRECIPITATION SHIELD, HOWEVER ANY AMOUNTS AND
ASSOCIATED THERMAL PROFILES WILL BE DETERMINED BY THE TRACK OF THE
SURFACE FEATURE GIVEN MOSTLY AN OVERRUNNING SCENARIO. THERE IS A CHC
THIS FEATURE TRACKS EVEN FARTHER SOUTH IF HIGH PRESSURE TO THE NORTH
IS STRONGER WITH ITS SOUTHWARD PUSH.
FOR TUESDAY AND WEDNESDAY...IT APPEARS ADDITIONAL ENERGY WILL BE
EJECTING NORTHEASTWARD AND WHILE THE EARLIER SURFACE LOW SHOULD BE
GONE TO START, A FRONTAL BOUNDARY MAY LINGER NEARBY TUESDAY. AS THE
UPPER-LEVEL TROUGH MIGRATES EAST SOME, THERE COULD BE SOME ENERGY
STILL SLIDING NORTHEASTWARD ALONG THE FRONT. AS OF NOW, WE FAVORED
MORE OF THE WPC GUIDANCE WHICH INDICATES A COLD FRONT SHIFTING
EAST TUESDAY AS STRONG HIGH PRESSURE BUILDS TOWARD THE CENTRAL
PLAINS AND ALSO EXPANDS TOWARD THE MID ATLANTIC INTO WEDNESDAY. THIS
RESULTS IN COLDER AIR SEEPING SOUTH AND EASTWARD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS WILL PERSIST IN OUR REGION INTO TONIGHT. CONDS HAVE
BEEN VARIABLE. THERE HAS BEEN A LULL IN THE PRECIP IN THE NEAR
TERM AND THIS SHOULD CONTINUE FOR THE NEXT LITTLE WHILE.
UNFORTUNATELY, IN SOME OF THESE AREAS, VSBYS HAVE DROPPED QUITE A
BIT, BUT FOR NOW THESE DROPS DON`T SEEM TO LAST ALL THAT LONG. THEREFORE,
WILL KEEP PREVAILING IFR CONDITIONS. THIS EVENING AND LATE
TONIGHT COULD ALSO SEE ISOLATED TSRA. WITH ANY TSRA COULD SEE VRB
AND GUSTY WINDS. HOWEVER, COVERAGE IS TOO LIMITED TO INCLUDE IN
THE TAFS AT THIS TIME.
A LOW LEVEL SOUTHERLY JET AS DEPICTED BY THE VAD WIND PROFILE FROM
KDIX CONTINUES OVER THE COASTAL PLAIN AND SHOULD PERSIST THROUGH AT
LEAST 06Z. AS A RESULT, WE HAVE CONTINUED THE MENTION OF LOW LEVEL WIND
SHEAR AT KTTN, KPNE, KPHL, KILG, KMIV AND KACY. BOTH KRDG AND KABE
SHOULD BE ENOUGH WEST OF THE LOW LEVEL JET.
AT THE SURFACE, GENERALLY LIGHT SOUTHERLY WINDS WILL CONTINUE UNTIL
THE COLD FRONT ARRIVES. THE COLD FRONT AND ASSOCIATED ABRUPT SHIFT
TO WESTERLY WINDS IS EXPECTED TO ARRIVE BETWEEN 06 AND 09Z. BEHIND
THE FRONT, EXPECT CONDITIONS TO IMPROVE TO MVFR, THEN VFR.
OUTLOOK...
THURSDAY NIGHT...VFR. WEST-NORTHWEST WINDS 10-15 KNOTS EARLY,
DIMINISHING TO LESS THAN 10 KNOTS.
FRIDAY AND SATURDAY...VFR, ALTHOUGH CLOUDS MAY INCREASE LATE
SATURDAY AS A COLD FRONT APPROACHES. SOUTHWEST WINDS MAINLY AROUND
10 KNOTS.
SUNDAY AND MONDAY...CLOUDS POTENTIALLY LOWER TO SUB-VFR AS A SYSTEM
TRACKS TO OUR SOUTH. THIS COULD RESULT IN SOME RAIN OR SNOW, HOWEVER
CONFIDENCE IS ON THE LOW SIDE. WINDS SHOULD TURN NORTHERLY.
&&
.MARINE...
SOUTHERLY WINDS WILL BE INCREASING SHORTLY, AND SHOULD SEE GUSTS
ABOVE 25KT ON ALL THE WATERS THROUGH THE EVENING HOURS. WITH THE
INCREASING WINDS, SEAS SHOULD ALSO BUILD BACK ABOVE 5 FT. AFTER
MIDNIGHT TONIGHT, LIKELY BETWEEN 2 AND 6 AM LST, A COLD FRONT WILL
PUSH THROUGH, BRINGING AN ABRUPT SHIFT TO WESTERLY WINDS. IN
ADDITION, COULD SEE ISOLATED THUNDERSTORMS WITH THE FRONT. UNDER ANY
THUNDERSTORMS, EXPECT VERY GUSTY WINDS. THE STRONG WESTERLY WINDS
WILL CONTINUE ON ALL THE WATERS THROUGH THE DAY TOMORROW. ALONG THE
OCEAN WATERS, ESPECIALLY THE NORTHERN NEW JERSEY COASTAL WATERS,
COULD SEE A FEW GUSTS ABOVE 30KT. HOWEVER, VERY UNCERTAIN IF WE WILL
REACH GALE FORCE GUSTS. THEREFORE, HAVE CANCELED THE GALE WATCH,
BUT AN SCA IS IN EFFECT FOR ALL THE WATERS THROUGH EARLY TOMORROW
EVENING. HOWEVER, WILL MONITOR WHEN THE NEW GUIDANCE COMES IN THIS
EVENING TO SEE IF THE THREAT FOR GALES FOR TOMORROW CHANGES.
OUTLOOK...
THURSDAY NIGHT...AS THE PRESSURE GRADIENT RELAXES, THE WINDS WILL AS
WELL. IT APPEARS THAT THE WINDS AND SEAS DECREASE FAIRLY QUICKLY,
THEREFORE A SMALL CRAFT ADVISORY WAS NOT EXTENDED AS OF NOW.
FRIDAY AND SATURDAY...THE CONDITIONS SHOULD BE BELOW SMALL CRAFT
ADVISORY CRITERIA AS HIGH PRESSURE BUILDS TO OUR SOUTH AND THEN
OFFSHORE. A WEAK COLD FRONT APPROACHES SATURDAY NIGHT.
SUNDAY AND MONDAY...A COLD FRONT SETTLES SOUTHEASTWARD ACROSS THE
AREA SUNDAY BUT THEN MAY STALL NEARBY. THE SOUTHWESTERLY FLOW MAY
INCREASE SOME AHEAD OF IT, THEN TURN NORTHWESTERLY IN ITS WAKE.
OVERALL, IT APPEARS THAT THE CONDITIONS REMAIN BELOW ADVISORY
CRITERIA. A WEAK LOW PRESSURE SYSTEM SHOULD DEVELOP ON THE FRONT AND
TRACK TO OUR SOUTH DURING THIS TIME FRAME.
&&
.TIDES/COASTAL FLOODING...
STILL A CONCERN FOR COASTAL FLOODING ALONG THE CHESAPEAKE BAY.
THOUGH GUIDANCE CONTINUES TO BE A BIT TOO HIGH, EVEN SUBTRACTING THE
BIAS, BOTH TIDAL GAUGES ALONG THE UPPER EASTERN SHORE WILL GET CLOSE
IF NOT EXCEED MINOR FLOODING THRESHOLDS FOR THE HIGH TIDE THIS
EVENING.
TO A LESSER EXTENT THERE IS A SMALL THREAT AGAIN TOMORROW MORNING
ALONG THE CHESAPEAKE. IT LOOKS LIKE WE SHOULD HAVE THE SHIFT TO
WESTERLY WINDS WELL BEFORE THE HIGH TIDE CYCLE, AND THE ASTRONOMICAL
TIDE IS LOWER, SO THE THREAT IS TOO LOW TO MENTION IN THE HWO FOR
NOW, BUT WILL CONTINUE TO MONITOR.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 10 PM EST THIS EVENING FOR MDZ008-
012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...JOHNSON/NIERENBERG
SHORT TERM...JOHNSON
LONG TERM...GORSE
AVIATION...GORSE/JOHNSON/NIERENBERG
MARINE...GORSE/JOHNSON
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
936 AM EST TUE DEC 23 2014
.DISCUSSION...
VISIBILITIES CONTINUE TO IMPROVE ACROSS THE REGION AND HAVE LET
THE DENSE FOG ADVISORY OVER OSCEOLA...INDIAN RIVER AND SOUTHERN
BREVARD COUNTIES EXPIRE. SOME STRATUS CONTINUES ACROSS THE AREA
BUT THIS WILL GRADUALLY BREAK UP AS DAYTIME HEATING CONTINUES AND
SOUTHERLY WINDS JUST OFF THE SURFACE UP TO 15-20 KTS INCREASE
BOUNDARY LAYER MIXING. DRIER/WARMER AIR JUST ABOVE 850MB EVIDENT
IN MORNING SOUNDING AT KMFL WILL ADVECT NORTHWARD INTO THE REGION
AND IMPEDE PRECIP DEVELOPMENT. HOWEVER WILL KEEP A SLIGHT CHANCE
OF SHOWERS NORTH OF ORLANDO WHERE THE HRRR MODEL STILL SHOWS THE
POTENTIAL FOR A FEW SHOWERS TO DEVELOP INTO THE AFT...WHICH
MATCHES UP WELL WITH MAV POPS. HIGH CLOUDS WILL CONTINUE TO PUSH
EASTWARD ACROSS CENTRAL FLORIDA WITH SKIES RANGING FROM PARTLY TO
MOSTLY CLOUDY. ABOVE NORMAL TEMPS EXPECTED TODAY WITH HIGHS IN THE
LOW TO MID 80S.
&&
.AVIATION...CIGS FROM 300-500FT IN STRATUS FROM THE I-4 CORRIDOR
NORTHWARD WILL CONTINUE TO BREAK UP AND LIFT INTO LATE MORNING
WITH VFR CONDS THEN EXPECTED ACROSS THE REGION THROUGH THE REST OF
THE DAY AND EVENING. THE WARM/MOIST SOUTHERLY FLOW WILL BRING LOW
STRATUS BACK TONIGHT BY AROUND MIDNIGHT. MOS SHOWS LIFR AT MOST
TERMINALS...BUT THINK THAT STRENGTHENING WINDS JUST ABOVE THE
SURFACE WILL LIKELY RESULT IN MAINLY IFR CEILINGS. THESE WINDS
WILL REQUIRE MENTION OF LOW LEVEL WIND SHEAR AT MOST SITES BY
MIDNIGHT.
&&
.MARINE...
TODAY-TONIGHT...NO CHANGES PLANNED AS FORECAST LOOKS ON TRACK.
(PREVIOUS DISCUSSION) CONDITIONS FOR SMALL CRAFT WILL DETERIORATE
AS SOUTHERLY WINDS INCREASE IN RESPONSE TO LOW PRESSURE MOVING
FROM THE WESTERN GULF TO MISSISSIPPI DELTA REGION THIS EVENING
WHILE STRENGTHENING. WILL CARRY AN EXERCISE CAUTION STATEMENT FOR
MOST OF THE WATERS AS WINDS INCREASE THIS AFTERNOON. WILL START AN
ADVISORY OFFSHORE NORTH OF SEBASTIAN INLET AROUND MIDNIGHT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR WINDS FROM 1 AM TO 10 PM EST WEDNESDAY
FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY
LINE 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
WEITLICH/CRISTALDI
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
432 AM EST TUE DEC 23 2014
...WIDESPREAD HEAVY RAINFALL AND WAVES OF STRONG TO SEVERE STORMS
EXPECTED THROUGH WED NIGHT...
.SHORT TERM...TODAY THROUGH WED NIGHT...
THIS MORNING...WARM FRONT WAS DRIFTING SLOWLY NORTHWARD OVERNIGHT BUT
HAS BECOME NEARLY STATIONARY EARLY THIS MORNING ALONG THE INTERSTATE
10 CORRIDOR. CLUSTERS OF RAINFALL WITH ISOLATED DISCRETE TSTORMS FIRED
OVERNIGHT ALONG AND SOUTH OF THE FRONT. A FEW STRONG STORMS PRODUCED
HAIL FROM 0.25-1" GIVEN COOLER 500 MB TEMPS NEAR -12 DEG C AND GOOD
DIRECTIONAL SHEAR WITHIN HAIL GROWTH ZONE. THE RAPID REFRESH INTIALIZED
BEST EARLY THIS MORNING WITH PRECIP BAND AND THE POSITION OF THE LINGERING
WARM FRONT THUS LEANED TOWARD THE HRRR SOLUTION FOR THE NEAR-TERM FORECAST
WHICH SHUNTS THE BAND OF EARLY MORNING RAINFALL SLOWLY NORTHWARD OVER
SE GA WITH PRECIP DECREASING ACROSS ATLANTIC COASTAL LOCATIONS. THE
FOCUS OF MORE SCATTERED TO WIDESPREAD RAINFALL AND ISOLATED TSTORMS
THEN SHIFTS OVER THE FL PANHANDLE WHERE LOW LEVEL INSTABILITY WILL
INTERSECT INCREASING UPPER LEVEL DYNAMICAL SUPPORT AHEAD OF APPROACHING
COLD FRONT. LOCALLY HEAVY RAINFALL WILL CONTINUE TO BE POSSIBLE IN SHOWERS
AND TSTORMS WITHIN THE WARM SECTOR ENVIRONMENT AS THE WARM FRONT LIFTS
NORTHWARD THROUGH MIDDAY OVER SE GA. DESPITE MOSTLY CLOUDY SKIES TEMPS
WILL WARM INTO THE 70S TODAY WITH ANONYMOUSLY HIGH DEW PTS IN THE MID/UPPER
60S WHICH WILL MAKE FOR UNSEASONABLY HUMID CONDITIONS.
THIS AFTN & TONIGHT...THE WARM FRONT IS EXPECTED TO BE ALONG OR JUST
NORTH OF THE ALTAMAHA RIVER BASIN THIS AFTN WITH INCREASINGLY HEAVY
AND WIDESPREAD RAINFALL ENCROACHING UPON THE SUWANNEE RIVER VALLEY
AND INLAND SE GA AS THE FRONTAL SYSTEM APPROACHES FROM THE WEST. THE
CONCERT OF INSTABILITY WITHIN THE WARM SECTOR AND LOW LEVEL JET DYNAMICS
UNDER DIVERGENT UPPER LEVEL FLOW WILL GRADUALLY SHIFT SLOWLY EASTWARD
THIS AFTN THROUGH TONIGHT WITH A TIGHT PRECIP CHANCE GRADIENT ACROSS
OUR FORECAST AREA. ADVERTISED 80% OR GREATER RAIN CHANCES FOR INLAND
SE GA TO THE SUWANNEE RIVER VALLEY BY MID AFTN TODAY THROUGH MUCH
OF TONIGHT. THIS TIME PERIOD IS WHEN THE HEAVIEST RAINFALL IS EXPECTED
DUE TO TRAINING OF CELLS REDEVELOPING FROM THE GULF COAST REGION WITH
WIDESPREAD RAINFALL AMOUNTS OF 3-5 INCHES POSSIBLE THROUGH WED NIGHT.
CONTINUED TO REFRAIN FROM A FLOOD WATCH UNTIL CONVECTIVE TRENDS BECOME
MORE ESTABLISHED.
WED...THE HEAVY PRE-FRONTAL PRECIP SHIELD WILL FINALLY BEGIN TO
TRANSLATE DOWNSTREAM ACROSS THE REMAINDER OF THE FORECAST AREA WED
MORNING AS THE PARENT UPPER LEVEL LOW TRACKS FARTHER EAST...BUT
THE TRAILING UPPER LEVEL TROUGH IS NOW PROGGED TO REMAIN NEG
TILTED WHICH FAVORS A SLOWER PASSAGE OF PRECIP ACROSS THE LOCAL
FORECAST WED AFTN INTO WED NIGHT. THERE REMAINS A LOW CHANCE OF
ISOLATED SEVERE STORMS WED ESPECIALLY ACROSS THE SUWANNEE RIVER
VALLEY OF NE FL BY EARLY AFTERNOON WHERE GULF INSTABILITY WILL
SURGE INLAND JUST AHEAD OF THE APPROACHING COLD FRONT AND JET
DYNAMICS PHASE. THE MAIN CONVECTIVE HAZARD WILL BE GUSTY WINDS OF
40-60 MPH BUT A FEW ROTATING CELLS MAY DEVELOP GIVEN STRONG
DIRECTIONAL SHEAR.
WED NIGHT...THE GFS IS STARTING TO HINT AT THE JAX SPLIT SCENARIO
IN PRECIP WED EVENING AS DYNAMICS EJECT OFF TO THE NE AND INSTABILITY
HUGS THE GULF COAST REGION. INDICATED THIS TREND IN THE LATEST
FORECAST WITH HIGHER RAIN CHANCES ALONG THE ATLANTIC COAST WED
EVENING AND GULF COAST AREAS WITH TSTORM POTENTIAL ENDING FROM NW-
SE THROUGH MIDNIGHT. LINGERING POST- FRONTAL SHOWERS STILL
EXPECTED EARLY THU WITH LAGGING MID LEVEL TROUGH AXIS. TEMPS WILL
COOL THROUGH WED NIGHT INTO THE UPPER 40S OVER INLAND SE GA TO THE
LOW/MID 50S OVER NE FL WHERE LINGERING PRECIP/CLOUDS ARE EXPECTED
AFTER MIDNIGHT.
CHRISTMAS DAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA
WITH DECREASING CLOUDINESS THURSDAY MORNING. DRIER AND COOLER
CONDITIONS WILL PREVAIL WITH LIGHT WINDS AND NEAR AVERAGE
TEMPERATURES.
.LONG TERM...FRIDAY THROUGH MONDAY...SURFACE HIGH MOVES OFF THE
EAST COAST FRIDAY WITH A RETURN FLOW BRINGING BACK MOISTURE. AN
ACTIVE SW FLOW ALOFT WILL BRING ANOTHER FRONTAL SYSTEM INTO THE SE
THIS WEEKEND INTO EARLY NEXT WEEK. MODEL DIFFERENCES PERSIST WITH
THE ECMWF KEEPING MOST OF PRECIP NORTH OF OUR AREA WHILE THE GFS
AND GFS ENSEMBLE BRINGS RAIN FURTHER SOUTH ACROSS SE GA. HAVE CHANCE
POPS MAINLY I-10 NORTHWARD WITH SLIGHT CHANCE TO THE SOUTH STARTING
SATURDAY. TEMPERATURES WILL BE NEAR AVERAGE ON FRIDAY AND THEN
SEVERAL DEGREES ABOVE AVERAGE INTO EARLY NEXT WEEK.
&&
.AVIATION...WAVES OF MVFR TO IFR CONDITIONS WILL CONTINUE TO LIFT
NORTH OF JAX/CRG/VQQ THIS MORNING WITH LIFR AT SSI EXPECTED TO
IMPROVE OVER THE NEXT SEVERAL HOURS TO MVFR THROUGH MIDDAY. EXPECT
PREVAILING VFR AT THE TERMINALS MIDDAY TODAY THROUGH EARLY AFTN
HOWEVER PERIODS OF MVFR TO IFR WILL BE POSSIBLE IN PASSING CONVECTION.
CONDITIONS WILL DETERIORATE GRADUALLY TONIGHT FROM W-E AS PRE-
FRONTAL WIDESPREAD RAINFALL FORMS ACROSS THE PANHANDLE AND INLAND
SE GA WITH PREVAILING MVFR LIKELY DEVELOPING OVERNIGHT TONIGHT.
&&
.MARINE...A WARM FRONT WILL GRADUALLY LIFT NORTHWARD OVER
SOUTHEAST GEORGIA THIS MORNING. SOUTH WINDS WILL INCREASE LATE
TONIGHT AHEAD OF A COLD FRONT WITH ADVISORY CONDITIONS EXPECTED
OVER THE OFFSHORE WATERS WITH SOUTH WINDS 20 KTS INCREASING TO
20-25 KTS WED. ISSUED A SMALL CRAFT ADVISORY FROM 08Z WED THROUGH
16Z THU. WAVES OF HEAVY RAINFALL AND ISOLATED STRONG THUNDERSTORMS
ARE EXPECTED UNTIL A COLD FRONT PUSHES ACROSS THE WATERS WEDNESDAY
NIGHT. WINDS AND SEAS WILL QUICKLY RELAX THURSDAY AFTERNOON AS
HIGH PRESSURE BUILDS OVER THE EASTERN GULF COAST REGION. THE RIDGE
WILL BUILD NORTHEAST OF THE LOCAL WATERS FRIDAY AND SATURDAY WITH
ONSHORE FLOW EXPECTED.
RIP CURRENTS: LOW RISK TODAY AND AGAIN WEDNESDAY ALTHOUGH
STRONGER LONG SHORE CURRENT WILL BE IN PLACE WED.
&&
.HYDROLOGY...RECENT HEAVY RAINFALL WITHIN THE ST.MARY`S RIVER
BASIN COULD BRING MINOR FLOODING AT MACCLENNY BY THE WEEKEND.
ADDITIONAL RIVERS INCLUDING THE ALAPAHA AND SUWANNEE WILL NEED TO
BE CLOSELY MONITORED GIVEN THEIR PROXIMITY TO THE HIGHER SWATH OF
EXPECTED STORM TOTAL PRECIPITATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 64 72 49 / 100 100 100 40
SSI 69 63 69 52 / 60 70 100 80
JAX 76 66 75 52 / 90 60 100 80
SGJ 75 67 74 55 / 30 50 100 80
GNV 76 67 74 53 / 30 70 100 70
OCF 78 67 76 54 / 20 60 100 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM 3 AM WEDNESDAY TO 11 AM EST THURSDAY
FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE.
&&
$$
ENYEDI/ZIBURA
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1232 AM EST TUE DEC 23 2014
.AVIATION...
FOG DEVELOP IS EXPECTED OVER THE INTERIOR AREAS OF SOUTH FLORIDA
EARLY THIS MORNING WHICH COULD SPREAD INTO THE FAR INTERIOR METRO
AREAS OF SOUTH FLORIDA. THEREFORE...THE CEILINGS SHOULD DROP DOWN
TO NEAR IFR CONDITIONS BETWEEN 9Z AND 12Z THIS MORNING FOR ALL OF
THE TAF SITES. THE VIS WILL ALSO FALL INTO THE MVFR CONDITIONS
BETWEEN 8Z AND 12Z THIS MORNING, EXCEPT FOR KTMB AND KAPF TAF
SITES WHERE THEY WILL FALL DOWN INTO THE IFR CONDITIONS.
THE LOW CLOUDS AND THE FOG SHOULD BURN OFF BY 14Z FOR THE TAF
SITES AS THE FOG BURNS OFF WITH PARTLY CLOUDY SKIES.
THEREFORE..THE CEILING AND VIS WILL BE IN VFR CONDITIONS AFTER 14Z
TODAY. THE WINDS WILL ALSO BE LIGHT AND VARIABLE THROUGH 14Z
BEFORE BECOMING EASTERLY BETWEEN 10 TO 15 KNOTS OVER ALL OF THE
TAF SITES.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 755 PM EST MON DEC 22 2014/
UPDATE...NO CHANGES TO THE FORECAST THIS EVENING. PWAT ON THE
EVENING MIAMI SOUNDING IS ONLY 1.34 INCHES AND WITH A LACK OF
FORCING, A TRANQUIL NIGHT IS EXPECTED TO CONTINUE. A RATHER MUGGY
LIGHT SOUTHEAST WIND FLOW WILL CONTINUE. READINGS WILL ONLY FALL
A FEW MORE DEGREES AS DEWPOINTS ARE NOW AROUND 70F, SO FORECAST
LOWS CONTINUE TO LOOK IN GOOD SHAPE AND NO CHANGES ARE NECESSARY
THIS EVENING. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 712 PM EST MON DEC 22 2014/
AVIATION...
MAIN CONCERN FOR THIS TAF CYCLE CONTINUES TO BE THE LOW CIG
POTENTIAL ACROSS ALL TAF SITES. SOUTHEAST FLOW SHOULD DECREASE
SLIGHTLY DURING THE OVERNIGHT PERIOD...LESS THAN 10
KNOTS...BEFORE INCREASING AGAIN DURING THE DAY TOMORROW. BELIEVE
THE BIGGEST THREAT FOR LOW CIGS SHOULD BE ACROSS THE INTERIOR AND
GULF COAST MAINLY AFFECTING KAPF. LATEST LAMP GUIDANCE ALONG WITH
THE HRRR IS EVEN SUGGESTING IFR CIGS OVERNIGHT AT KAPF. DECIDED TO
INTRODUCE A TEMPO MENTION FOR BRIEF IFR CIGS AND MVFR VSBY AT KAPF
AS GUIDANCE HAS REMAINED FAIRLY CONSISTENT OVER THE LAST 24 HOURS.
GUIDANCE WAS FAIRLY UNIFORM DEPICTING MVFR CIGS AT ALL EAST COAST
SITES THROUGH MUCH OF THE OVERNIGHT AND EARLY MORNING PERIOD...SO
PREVAILED BKN010-015 AFTER 08Z. COULD SEE BRIEF IFR CIGS AT KTMB
BUT LEFT MENTION OUT OF TAFS FOR NOW.
&&
PREV DISCUSSION... /ISSUED 312 PM EST MON DEC 22 2014/
DISCUSSION...
DRY...WARM AND PARTLY SUNNY CONDITIONS CONTINUE ACROSS SOUTH
FLORIDA THIS AFTERNOON. THE MID/UPPER LEVEL PATTERN CONSISTED OF
A RIDGE OF HIGH PRESSURE CENTERED NEAR THE DOMINICAN REPUBLIC AND
STRETCHING NORTHWARD OVER THE WESTERN ATLANTIC NEAR THE EASTERN
SEABOARD...AND A TROUGH DIGGING INTO THE NORTHERN/CENTRAL PLAINS.
AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN
ATLANTIC...WITH A SOUTHEAST FLOW ACROSS SOUTH FLORIDA. THE
SOUTHEAST FLOW WAS BRINGING INCREASING DEWPOINTS ACROSS THE
REGION...AND TEMPERATURES OVERNIGHT ALONG THE EAST COAST WILL
REMAIN WELL ABOVE NORMAL IN THE LOWER 70S.
AN AMPLIFIED PATTERN WILL REMAIN IN PLACE ON TUESDAY AS THE UPPER
TROUGH DIGS INTO TEXAS AND THE UPPER RIDGE REMAINS OVER THE
CARIBBEAN AND ALONG THE EASTERN SEABOARD. AN AREA OF LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THE NORTHERN GULF COAST...AND THE
PRESSURE GRADIENT WILL INCREASE IN THE AFTERNOON. DRY LOW/MID
LEVEL AIR WILL CONTINUE TO PUSH INTO THE REGION ON
TUESDAY...ROTATING AROUND HIGH PRESSURE OVER THE WESTERN ATLANTIC.
SO ANOTHER DRY...MUGGY AND WARM DAY IS IN STORE FOR SOUTH
FLORIDA...WITH TEMPERATURES IN THE LOW TO MID 80S AND DEWPOINTS
AROUND 70. OVERNIGHT LOWS WILL BE VERY WARM ONCE AGAIN...AND NEAR
RECORD HIGH MINIMUMS IN THE UPPER 60S TO MID 70S.
LOW PRESSURE IS FORECAST TO PUSH INTO THE SOUTHEAST AND THEN OHIO
VALLEY ON WEDNESDAY...WITH TRAILING COLD FRONT PUSHING INTO THE
FLORIDA PENINSULA. MODEL GUIDANCE HAS CONTINUED TO SLOW DOWN THE
TIMING OF THE FRONT...AND IT APPEARS THE FRONT WILL MOVE INTO THE
REGION LATE WEDNESDAY. THE FRONT IS THEN FORECAST TO PUSH THROUGH
THE REGION ON CHRISTMAS MORNING. HOWEVER...MOISTURE WILL LINGER
BEHIND THE FRONT...WITH CLOUD COVER AND SHOWERS REMAINING INTO THE
AFTERNOON HOURS. THE BEST DYNAMICS WILL REMAIN ACROSS CENTRAL
FLORIDA AND THEN OUT INTO THE WESTERN ATLANTIC. INSTABILITY WILL
ALSO BE MARGINAL AS THE FRONT MOVES INTO THE REGION
OVERNIGHT...AND WINDS MAY ALSO VEER TO THE SOUTHWEST AHEAD OF THE
FRONT. SPC HAS THE REGION IN A MARGINAL RISK FOR SEVERE WEATHER.
THE BEST BET FOR STRONGER STORMS APPEARS TO BE FROM NAPLES TO THE
LAKE REGION AND NORTHWARD.
RIDGING WILL HOLD ON OVER THE CARIBBEAN AND BAHAMAS...AND THE
TROUGH WILL LIFT NORTHEASTWARD AND FLATTEN OUT ON THURSDAY. THE
FRONT WILL THEN STALL OVER THE FLORIDA STRAITS THROUGH THE END OF
THE WEEK...WITH HIGH PRESSURE BUILDING INTO THE SOUTHEAST AND THEN
WESTERN ATLANTIC. SO COLD AIR ADVECTION WILL BE SHORT
LIVED...WITH TEMPERATURES ONLY BRIEFING FALLING TO NEAR NORMAL FOR
CHRISTMAS DAY AND FRIDAY.
THE MID/UPPER LEVEL RIDGE IS FORECAST TO BUILD ACROSS THE REGION
OVER THE WEEKEND. MOISTURE WILL QUICKLY RETURN...WITH DEWPOINTS
INCREASING BACK INTO THE MID TO UPPER 60S. TEMPERATURES ARE
FORECAST TO INCREASE TO THE UPPER 70S TO LOWER 80S. A SHORTWAVE
WILL PUSH ACROSS THE FOUR CORNERS REGION ON SATURDAY AND THEN LIFT
NORTHEAST AROUND THE RIDGE OF HIGH PRESSURE INTO THE OHIO VALLEY
ON SUNDAY. A SURFACE LOW IS THEN FORECAST TO PUSH INTO THE
NORTHEAST OR GREAT LAKES...WITH A WEAK FRONT PUSHING INTO
NORTHERN AND CENTRAL FLORIDA BEFORE STALLING.
MARINE...
SOUTHEAST FLOW CONTINUES THROUGH TUESDAY, WITH WINDS VEERING TO
THE SOUTH ON WEDNESDAY. A COLD FRONT WILL APPROACH THE GULF
WATERS WEDNESDAY AFTERNOON, THEN INTO THE ATLANTIC WATERS LATE
WEDNESDAY INTO EARLY CHRISTMAS DAY. NORTHWEST AND NORTH WINDS ARE
EXPECTED BY THURSDAY. SEAS WILL BUILD, ESPECIALLY THROUGH THE
OFFSHORE GULF WATERS WEDNESDAY NIGHT INTO EARLY CHRISTMAS DAY.
HIGH PRESSURE AND NORTHEASTERLY FLOW RETURN TO END THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 84 68 74 / 10 20 60 30
FORT LAUDERDALE 75 83 70 75 / 10 20 60 30
MIAMI 73 84 69 76 / 10 20 60 30
NAPLES 69 82 66 71 / 10 50 60 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...84/AK
LONG TERM....23/SK
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
656 PM EST WED DEC 24 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA THIS EVENING. SUNSHINE AND
SEASONABLE TEMPERATURES WILL RETURN FOR CHRISTMAS DAY WITH BREEZY
CONDITIONS AS HIGH PRESSURE BUILDS INTO THE AREA. THE CHANCE FOR
RAIN WILL RETURN LATE SATURDAY AND INTO MONDAY AS LOW PRESSURE
DEVELOPS ALONG THE GULF COAST STATES AND MOVES NORTHEAST.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
REGIONAL RADAR INDICATING BULK OF SHOWERS MOVING EAST OF THE
MIDLANDS AT 23Z. COLD FRONT MOVING INTO EAST CENTRAL GEORGIA.
LATEST RAP MODEL INDICATES FRONT THROUGH CAE AT 03Z.LIGHT RAIN AND
OR DRIZZLE EXPECTED FOR THE NEXT COUPLE OF HOURS AHEAD OF THE COLD
FRONT.
BEHIND THE FRONT TONIGHT...COOLER AND DRIER AIR WILL BUILD INTO
THE REGION OVERNIGHT WITH LOWS FALLING INTO THE 40S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
THURSDAY THROUGH THURSDAY NIGHT...CHRISTMAS DAY WILL FEATURE A DRY
FORECAST WITH POSSIBLY BREEZY CONDITIONS IN THE MORNING AS HIGH
PRESSURE BUILDS INTO THE REGION. MOSTLY SUNNY SKIES WITH A DRY
ATMOSPHERIC COLUMN DEPICTED BY FORECAST SOUNDINGS. SEASONABLE
TEMPERATURES WITH HIGHS IN THE UPPER 50S TO LOWER 60S. STRONG
RADIATIONAL COOLING CONDITIONS EXPECTED THURSDAY NIGHT WITH HIGH
PRESSURE BECOMING ANCHORED OVER THE AREA WITH LOW TEMPERATURES IN
THE LOWER 30S.
FRIDAY AND FRIDAY NIGHT...A RIDGE OF HIGH PRESSURE WILL REMAIN
ACROSS THE REGION...BRINGING CONTINUED DRY WEATHER THROUGH FRIDAY
NIGHT. SKIES WILL REMAIN MOSTLY SUNNY ON FRIDAY...WITH SOME MID AND
UPPER LEVEL CLOUD COVER BEGINNING TO ENTER THE REGION FROM THE
SOUTHWEST FRIDAY NIGHT. WINDS SHOULD BE GENERALLY LIGHT AND VARIABLE.
HIGHS DURING THE DAY ON FRIDAY WILL BE SLIGHTLY ABOVE NORMAL...WITH
MOST AREAS CLIMBING TO AROUND 60 DEGREES. FRIDAY NIGHT LOWS WILL
DEPEND ON THE TIMING AND DEGREE OF THE CLOUD COVER. AT THIS TIME
TEMPERATURES WILL FALL TO THE UPPER 30S AND LOWER 40S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SURFACE AND UPPER RIDGE WILL BE MOVING OFF THE EAST COAST ON
SATURDAY. MOISTURE WILL INCREASE ALOFT AS SOUTHWESTERLY WINDS BEGIN
TO BRING GULF MOISTURE NORTHWARD. AT THE SURFACE SOME ATLANTIC
MOISTURE MAY BE ABLE TO MOVE INLAND DURING THE DAY. MODELS BEGIN
TRYING TO BRING RAINFALL TOWARDS THE REGION FROM THE SOUTHWEST
DURING THE DAY. AT THIS TIME THE DEEP MOISTURE RETURN MAY NOT
ARRIVE UNTIL LATER IN THE AFTERNOON. FORECAST AREA SHOULD REMAIN
DRY EARLY IN THE DAY...THEN EXPECT TO SEE INCREASING RAIN CHANCES
FROM THE SOUTHWEST LATER IN THE DAY.
FROM SATURDAY NIGHT THROUGH WEDNESDAY THE LONGER RANGE
MODELS...GFS40/ECMWF...ARE IN BETTER AGREEMENT WITH THE GENERAL
UPPER LEVEL PATTERN. MAIN UPPER FLOW REMAINS SOUTHWESTERLY...BRINGING
GULF MOISTURE NORTHWARD. AT THE SURFACE...A FRONT WILL BE PUSHING
EASTWARD TOWARDS THE CWA ON SUNDAY...WITH A POSSIBLE AREA OF LOW
PRESSURE MOVING NORTHWARD ALONG THE FRONT. THE FRONT WILL SLOWLY
PUSH THROUGH THE AREA THROUGH MONDAY. UNTIL THE FRONT PUSHES
THROUGH...THE FORECAST AREA SHOULD HAVE A GOOD CHANCE OF SEEING
RAINFALL FROM SATURDAY NIGHT THOUGH MONDAY NIGHT...AND WILL
CONTINUE WITH CURRENT CHANGE POPS THROUGH THAT PERIOD. AS THE COLD
FRONT PUSHES SOUTH ON TUESDAY...DRIER AIR WILL TRY TO MOVE IN FROM
THE NORTH THROUGH WEDNESDAY. TEMPERATURES AHEAD OF THE FRONT WILL
REMAIN ABOVE NORMAL...THEM FALL BACK DOWN TO NORMAL OR BELOW
NORMAL TUESDAY INTO WEDNESDAY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RESTRICTIONS TO CONTINUE FOR THE NEXT SEVERAL HOURS WITH
IMPROVEMENT OVERNIGHT AS THE COLD FRONT CROSSES THE TAF SITES.
MAJORITY OF SHOWERS HAVE MOVED EAST OF THE TAF SITES WITH FOG AND
DRIZZLE PERSISTING ACROSS THE AREA. COLD FRONT CURRENTLY MOVING
THROUGH CENTRAL GA WILL CROSS THE TAF SITES OVERNIGHT RESULTING IN
IMPROVING CONDITIONS AS DRIER AIR MOVES IN BEHIND THE FRONT.
EXPECT VFR CONDITIONS TO RETURN TO AGS/DNL AROUND 02Z AND
CAE/CUB/OGB AROUND 03Z. WINDS WILL ALSO VEER TO WESTERLY AND
BECOME GUSTY WITH FROPA.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE SATURDAY EVENING
THROUGH MONDAY AS THE NEXT FRONTAL SYSTEM MOVES INTO AND STALLS
ACROSS THE REGION.
&&
.HYDROLOGY...
MODERATE TO HEAVY RAINFALL OVER THE PAST 24 HOURS HAS YIELDED
WIDESPREAD RAINFALL AMOUNTS OF 2 TO 4 INCHES. MAINSTEM RIVERS ARE
EXPECTED TO RESPOND TO THE SIGNIFICANT RAINFALL AND RISE OVER THE
NEXT FEW DAYS. AT THIS TIME THE SERFC IS FORECASTING SOME MINOR
FLOODING ALONG THE CONGAREE RIVER AT CAROLINA EASTMAN AND MEETING
ADVISORY CRITERIA AT THE CONGAREE RIVER AT COLUMBIA. THE ENOREE
RIVER AT WHITMIRE WILL BE CLOSE AS WELL.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1236 PM CST TUE DEC 23 2014
.UPDATE...
1037 AM CST
CHRISTMAS EVE STORM UPDATE...
THE LATEST AVAILABLE 12Z GUIDANCE HAS HONED IN PRETTY CLOSELY ON A
LOW PRESSURE TRACK FROM FROM CENTRAL KY TO NEAR IND TO CENTRAL OR
SOUTHWEST LOWER MI ON WEDNESDAY. THIS GIVES US MORE CONFIDENCE IN
WHERE THE HEAVIEST SWATH OF PRECIPITATION WILL FALL IN THE INTENSE
DEFORMATION AXIS. THERE IS A STILL A SIGNIFICANT TIMING
DISCREPANCY BETWEEN THE NAM ON THE SLOW END OF THE GUIDANCE
ENVELOPE AND 12Z GFS ON THE FASTEST END...AS IT HAS CONSISTENTLY
SHOWN FOR SEVERAL MODEL CYCLES. SO CONFIDENCE IS LOWER ON TIMING
AND DURATION OF HEAVY PRECIP...WITH THE GFS SUGGESTING THAT THE
BULK OF THE PRECIPITATION FALLS BETWEEN 06Z AND 18Z...WHILE THE
NAM FAVORS THE HEAVIEST PRECIPITATION OVER THE CHICAGO METRO AND
POINTS EAST FROM THE LATE MORNING UNTIL THE LATE AFTERNOON.
THE BIGGEST QUESTION MARK REMAINS WITH THE VERY MARGINAL BOUNDARY
LAYER CONDITIONS FOR SNOW AT PRECIP ONSET AND THROUGH MUCH OF THE
EVENT. PRECIPITATION IS EXPECTED TO START AS RAIN THEN FLIP OVER
TO SNOW. THE THINKING IS THAT THE GFS IS NOT HANDLING THE DYNAMIC
COOLING OFFERED BY THE INTENSE UPWARD MOTION IN THE HEART OF THE
FRONTOGENETICALLY DRIVEN DEFORMATION BAND...AND THUS REMAINS TOO
WARM WITH NEAR SFC THERMAL PROFILES AND MOST OF THE PRECIP FALLS
IN THE FORM OF RAIN/MIX. THE FORECAST WILL LEAN IN FAVOR OF
DYNAMIC COOLING OFFSETTING THE INITIALLY MARGINAL
CONDITIONS...WHICH IS CAPTURED WELL BY THE 12Z NAM. HOWEVER...IT
WILL LIKELY BE A VERY LOW SNOW TO LIQUID RATIO SNOW AND THE HUGE
SNOWFALL AMOUNTS ON THE NAM COBB OUTPUT ARE VERY LIKELY OVERDONE.
WOULD LIKE TO SEE THE REST OF THE 12Z GUIDANCE BEFORE MAKING ANY
HEADLINE DECISIONS...WHICH WILL LIKELY BE MADE BY THE EARLY
AFTERNOON. OVERALL THINKING REMAINS THAT CONFIDENCE IS GROWING IN
A HIGH IMPACT SNOW EVENT ACROSS PART OF THE CWA TOMORROW...WHICH
IS BECOMING MORE LIKELY TO INCLUDE THE CHICAGO METRO. THE SPS HAS
BEEN UPDATED.
RC
&&
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* BURST OF HEAVY WET SNOW LIKELY WEDNESDAY FROM MIDDAY THROUGH THE AFTERNOON.
* A PERIOD OF VLIFR CONDITIONS POSSIBLE WEDNESDAY AFTERNOON WITH
HEAVY WET SNOW.
* EXACT LOCATION OF BAND OF HEAVIEST SNOW REMAINS UNCERTAIN. SNOW
AMOUNTS WILL DROP OFF SHARPLY TO EITHER SIDE.
ED F
//DISCUSSION...UPDATED 18Z...
COMPLICATED WEATHER SITUATION UNFOLDING FOR WEDNESDAY WITH
POTENTIAL FOR VERY LOW CIGS AND VSBYS ASSOCIATED WITH BAND OF
HEAVY WET SNOW. FIRST... SOUTHWEST WINDS WILL CONTINUE TO GUST
20-25 KT THIS AFTERNOON WITH LOW CLOUDS LURKING JUST TO THE
NORTHWEST OF ORD/MDW AS LOW PRESSURE TRACKS NE ACROSS WISCONSIN
REACHING NORTHERN LAKE MICHIGAN TONIGHT. WINDS WILL SLACKEN AS THE
LOW PULLS AWAY TONIGHT WITH CIGS LOWERING OVERNIGHT.
MEANWHILE... POWERFUL LOW PRESSURE MOVING FROM THE OHIO VALLEY TO
LOWER MICHIGAN BY LATE DAY WEDNESDAY WILL LIKELY BRING RAIN
CHANGING TO HEAVY WET SNOW QUICKLY WEDNESDAY MID-LATE MORNING WITH
THE POTENTIAL FOR SNOWFALL RATES OF 1 TO LOCALLY OVER 2 INCHES PER
HOUR WITH VERY LOW CIGS AND VSBYS POSSIBLE. WHILE MODELS TRENDING MORE
CONSISTENT ON OVERALL SCENARIO... DIFFERENCES REMAIN THAT CAN MAKE
THE DIFFERENCE IN EXACTLY WHERE THE NARROW BAND OF HEAVIEST SNOW
THAT THIS SYSTEM IS CAPABLE OF WILL SET UP. COMING FORECASTS
WILL SEEK TO FURTHER REFINE THE EXACT LOCATION OF THIS
POTENTIALLY HIGHLY IMPACTFUL EVENT.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH ON CIG TRENDS AND WINDS THIS AFTERNOON/EVENING.
* MEDIUM TO HIGH ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND TIMING OF CHANGE OVER FROM RA TO SN... AS WELL
AS HOW POOR CONDITIONS MAY DETERIORATE TO.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1140 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 1030 AM CST TUE DEC 23 2014
Weak low pressure center at the sfc moving NE from east central IA
this morning, as a dry slot built into Central Illinois resulting
in long absent sunshine for the area. Cirrus building in from the
south will slowly cloud back over and the day should wrap up
rather cloudy again. Temperatures on track for the afternoon with
southwesterly winds. Quiet weather expected through the afternoon,
with a break between the two systems. Forecast looking good and no
updates are anticipated in the short term.
&&
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Back edge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CST TUE DEC 23 2014
Will be issuing a Special Weather Statement to address the 1-3inch
snow accumulations with locally 3 to 4 inches west of I-57 to near
the IL river on Wed and Wed evening. 00Z models have trended
further west (especially NAM model) up Indiana Wed with
deformation/trowal setting up over central and northeast IL on Wed.
Rain spread back northward across se IL this evening and over rest
of central IL overnight with chance of light snow late tonight
west of the IL river. But appears warm enough for most areas
tonight to just get rain. Lows tonight in mid 30s from I-55 nw to
upper 30s to around 40F in eastern/southeast IL.
Surface low pressure to deepen and lift nne from the nw Gulf of
Mexico across central Indiana Wed and into eastern lower MI by Wed
evening. Strong upper level low to pivot across IL Wed afternoon
and expect rain to change to wet snow from west to east during the
day Wed. Snow to diminish from west to east during Wed night. Best
snow accumulations to occur over western IL Wed morning with 1
inch or less while snow accumulations 1-3 inches from IL river
east toward I-57 Wed afternoon/evening with locally 3-4 inches
near I-55 and into ne IL. Morning highs Wed in mid to upper 30s
central IL and lower 40s eastern/se IL and then slipping into low
to mid 30s by end of day Wed as strong west/nw winds kick in
during day Wed into Wed night with gusts 25 to 35 mph.
Christmas day still looks dry with return of some sunshine
especially sw counties as strong low pressure exits into Quebec
and 1025 mb surface high pressure sets up over southeast states.
A southerly flow sets up by Thu afternoon with highs in the upper
30s to lower 40s so any snow that fall Wed/Wed evening will likely
melt on Thu afternoon.
Another area of low pressure ejects ne from CO into WI by Fri
evening and swings a cold front se across central IL Fri night and
near southeast IL Sat. Milder highs in mid to upper 40s on Friday
with IL getting in warm sector. Then precipitation chances
increasing during Friday night into Sat especially over southeast
IL. Southeast IL looks warm enough for mainly rain (turning to mix
during day on Sat) with mix of light rain/snow central IL but
little accumulations. Highs Sat range from lower 30s nw of IL
river to lower 40s along the Wabash River.
ECMWF model is further north with southern low pressure system and
qpf into southeast IL Sat night through Sunday eve and drawing in
colder air and cold enough for light snow. Have chance of light
snow southeast IL Sat night and Sunday with slight chances over
central IL. Seasonably cold highs in the low to mid 30s on Sunday.
Quieter weather returns early next work week with seasonable temps
for late Dec.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1136 AM CST TUE DEC 23 2014
Not much in the way of changes in the shorter term TAF this
morning. Cirrus closing in the gap in the dry slot this morning
and mid level clouds anticipated by later this afternoon. Winds
becoming light and variable in the evening as MVFR clouds begin to
build back into the region from the SE as the next low pressure
system slides north into the area. Same low pressure system will
bring increasing chances for rain, eventually changing over to
snow mid morning. Timing is still low confidence, but needed to
start the trend. Should be all snow by noon in both SPI and PIA
and close to all snow in other terminals as well.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...07
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1037 AM CST TUE DEC 23 2014
.UPDATE...
1037 AM CST
CHRISTMAS EVE STORM UPDATE...
THE LATEST AVAILABLE 12Z GUIDANCE HAS HONED IN PRETTY CLOSELY ON A
LOW PRESSURE TRACK FROM FROM CENTRAL KY TO NEAR IND TO CENTRAL OR
SOUTHWEST LOWER MI ON WEDNESDAY. THIS GIVES US MORE CONFIDENCE IN
WHERE THE HEAVIEST SWATH OF PRECIPITATION WILL FALL IN THE INTENSE
DEFORMATION AXIS. THERE IS A STILL A SIGNIFICANT TIMING
DISCREPANCY BETWEEN THE NAM ON THE SLOW END OF THE GUIDANCE
ENVELOPE AND 12Z GFS ON THE FASTEST END...AS IT HAS CONSISTENTLY
SHOWN FOR SEVERAL MODEL CYCLES. SO CONFIDENCE IS LOWER ON TIMING
AND DURATION OF HEAVY PRECIP...WITH THE GFS SUGGESTING THAT THE
BULK OF THE PRECIPITATION FALLS BETWEEN 06Z AND 18Z...WHILE THE
NAM FAVORS THE HEAVIEST PRECIPITATION OVER THE CHICAGO METRO AND
POINTS EAST FROM THE LATE MORNING UNTIL THE LATE AFTERNOON.
THE BIGGEST QUESTION MARK REMAINS WITH THE VERY MARGINAL BOUNDARY
LAYER CONDITIONS FOR SNOW AT PRECIP ONSET AND THROUGH MUCH OF THE
EVENT. PRECIPITATION IS EXPECTED TO START AS RAIN THEN FLIP OVER
TO SNOW. THE THINKING IS THAT THE GFS IS NOT HANDLING THE DYNAMIC
COOLING OFFERED BY THE INTENSE UPWARD MOTION IN THE HEART OF THE
FRONTOGENETICALLY DRIVEN DEFORMATION BAND...AND THUS REMAINS TOO
WARM WITH NEAR SFC THERMAL PROFILES AND MOST OF THE PRECIP FALLS
IN THE FORM OF RAIN/MIX. THE FORECAST WILL LEAN IN FAVOR OF
DYNAMIC COOLING OFFSETTING THE INITIALLY MARGINAL
CONDITIONS...WHICH IS CAPTURED WELL BY THE 12Z NAM. HOWEVER...IT
WILL LIKELY BE A VERY LOW SNOW TO LIQUID RATIO SNOW AND THE HUGE
SNOWFALL AMOUNTS ON THE NAM COBB OUTPUT ARE VERY LIKELY OVERDONE.
WOULD LIKE TO SEE THE REST OF THE 12Z GUIDANCE BEFORE MAKING ANY
HEADLINE DECISIONS...WHICH WILL LIKELY BE MADE BY THE EARLY
AFTERNOON. OVERALL THINKING REMAINS THAT CONFIDENCE IS GROWING IN
A HIGH IMPACT SNOW EVENT ACROSS PART OF THE CWA TOMORROW...WHICH
IS BECOMING MORE LIKELY TO INCLUDE THE CHICAGO METRO. THE SPS HAS
BEEN UPDATED.
RC
&&
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIGS VARIABLE THROUGH 18Z WITH MVFR CIGS IN AND OUT
* VFR CONDITIONS PREVAILING BY 18Z... MAY SEE BRIEF MVFR CONTINUING
* VLIFR CONDITIONS POSSIBLE WEDNESDAY WITH STRONG STORM SYSTEM AND
POTENTIAL FOR HEAVY WET SNOW... FROM AROUND MIDDAY THROUGH THE
AFTERNOON.
ED F
//DISCUSSION...UPDATED 12Z...
WINDS WILL PICK UP A BIT OUT OF THE SOUTH-SOUTHWEST BY MID MORNING
AS A FRONTAL BOUNDARY LIFTS NORTHWARD ACROSS THE AREA. IT ALSO
APPEARS THAT CIGS WILL BE ON AN IMPROVING TREND TODAY...WITH VFR
CONDITIONS LOOKING TO BE A GOOD POSSIBLY BY LATE MORNING. THE NEXT
MAIN WEATHER CONCERN WILL BE ON WEDNESDAY AS A STRENGTHENING STORM
SYSTEM LIFTS UP THE OHIO VALLEY AND INTO LOWER MICHIGAN. THIS
STORM SYSTEM LOOKS TO RESULT IN ANOTHER PERIOD OF PRECIPITATION
ACROSS THE AREA...AND A DECENT POTENTIAL FOR THIS TO CHANGE OVER
TO SOME HEAVY WET SNOW. ALTHOUGH CONFIDENCE IS INCREASING THAT
THIS PRECIPITATION WILL CHANGE OVER TO SNOW...UNCERTAINTY REMAINS
RATHER HIGH AS TO THE EXACT TIMING THIS MAY OCCUR ON WED. IF THE
HEAVY SNOW DOES MATERIALIZE...PERIODS OF IFR TO VLIFR VIS AND
CIGS WOULD BE LIKELY AT TIMES DURING THE DAY.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM ON CIG TRENDS... HIGH ON WINDS.
* MEDIUM TO HIGH ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND TIMING OF CHANGE OVER FROM RA TO SN... AS WELL
AS HOW POOR CONDITIONS MAY DETERIORATE TO.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1035 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 1030 AM CST TUE DEC 23 2014
Weak low pressure center at the sfc moving NE from east central IA
this morning, as a dry slot built into Central Illinois resulting
in long absent sunshine for the area. Cirrus building in from the
south will slowly cloud back over and the day should wrap up
rather cloudy again. Temperatures on track for the afternoon with
southwesterly winds. Quiet weather expected through the afternoon,
with a break between the two systems. Forecast looking good and no
updates are anticipated in the short term.
&&
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Backedge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CST TUE DEC 23 2014
Will be issuing a Special Weather Statement to address the 1-3inch
snow accumulations with locally 3 to 4 inches west of I-57 to near
the IL river on Wed and Wed evening. 00Z models have trended
further west (especially NAM model) up Indiana Wed with
deformation/trowal setting up over central and northeast IL on Wed.
Rain spread back northward across se IL this evening and over rest
of central IL overnight with chance of light snow late tonight
west of the IL river. But appears warm enough for most areas
tonight to just get rain. Lows tonight in mid 30s from I-55 nw to
upper 30s to around 40F in eastern/southeast IL.
Surface low pressure to deepen and lift nne from the nw Gulf of
Mexico across central Indiana Wed and into eastern lower MI by Wed
evening. Strong upper level low to pivot across IL Wed afternoon
and expect rain to change to wet snow from west to east during the
day Wed. Snow to diminish from west to east during Wed night. Best
snow accumulations to occur over western IL Wed morning with 1
inch or less while snow accumulations 1-3 inches from IL river
east toward I-57 Wed afternoon/evening with locally 3-4 inches
near I-55 and into ne IL. Morning highs Wed in mid to upper 30s
central IL and lower 40s eastern/se IL and then slipping into low
to mid 30s by end of day Wed as strong west/nw winds kick in
during day Wed into Wed night with gusts 25 to 35 mph.
Christmas day still looks dry with return of some sunshine
especially sw counties as strong low pressure exits into Quebec
and 1025 mb surface high pressure sets up over southeast states.
A southerly flow sets up by Thu afternoon with highs in the upper
30s to lower 40s so any snow that fall Wed/Wed evening will likely
melt on Thu afternoon.
Another area of low pressure ejects ne from CO into WI by Fri
evening and swings a cold front se across central IL Fri night and
near southeast IL Sat. Milder highs in mid to upper 40s on Friday
with IL getting in warm sector. Then precipitation chances
increasing during Friday night into Sat especially over southeast
IL. Southeast IL looks warm enough for mainly rain (turning to mix
during day on Sat) with mix of light rain/snow central IL but
little accumulations. Highs Sat range from lower 30s nw of IL
river to lower 40s along the Wabash River.
ECMWF model is further north with southern low pressure system and
qpf into southeast IL Sat night through Sunday eve and drawing in
colder air and cold enough for light snow. Have chance of light
snow southeast IL Sat night and Sunday with slight chances over
central IL. Seasonably cold highs in the low to mid 30s on Sunday.
Quieter weather returns early next work week with seasonable temps
for late Dec.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 530 AM CST TUE DEC 23 2014
MVFR and local IFR cigs will become VFR this morning with PIA on
the edge of some wrap around moisture from the departing storm
system. Forecast soundings showing despite the loss of the low
level moisture, quite a bit of mid and high level cloud cover
will affect the TAF sites this morning into the afternoon hours
before more MVFR cigs approach the area for late this evening and
into the overnight hours ahead of the next storm system. As the
next storm system approaches from the south tonight, rain will
overspread the area from south to north after 04z with CMI and
DEC the first to see the rain followed by SPI and BMI aftr 06z
and then PIA during the early morning hours. Once the rain begins
it appears the cigs will quickly drop to MVFR and then eventually
IFR once again, but at this time will hold off bringing cigs and
or vsbys down too much in this forecast period as it appears the
IFR and LIFR cigs will be during the day Wed. Surface winds will
be out of the southwest today at 10 to 15 kts, and the gradually
turn into a light northwest to north direction tonight at 4 to
9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
538 AM CST TUE DEC 23 2014
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACORSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CIG TRENDS TODAY...WITH VFR CONDITIONS POSSIBLE BY LATE
MORNING/EARLY AFTERNOON.
* STRONG STORM SYSTEM TO IMPACT THE REGION ON
WEDNESDAY...POTENTIAL FOR SOME HEAVY WET SNOW AND VERY LOW
CONDITIONS...ESPECIALLY IN THE AFTERNOON.
KJB
//DISCUSSION...UPDATED 12Z...
WINDS WILL PICK UP A BIT OUT OF THE SOUTH-SOUTHWEST BY MID MORNING
AS A FRONTAL BOUNDARY LIFTS NORTHWARD ACROSS THE AREA. IT ALSO
APPEARS THAT CIGS WILL BE ON AN IMPROVING TREND TODAY...WITH VFR
CONDITIONS LOOKING TO BE A GOOD POSSIBLY BY LATE MORNING. THE NEXT
MAIN WEATHER CONCERN WILL BE ON WEDNESDAY AS A STRENGTHENING STORM
SYSTEM LIFTS UP THE OHIO VALLEY AND INTO LOWER MICHIGAN. THIS
STORM SYSTEM LOOKS TO RESULT IN ANOTHER PERIOD OF PRECIPITATION
ACROSS THE AREA...AND A DECENT POTENTIAL FOR THIS TO CHANGE OVER
TO SOME HEAVY WET SNOW. ALTHOUGH CONFIDENCE IS INCREASING THAT
THIS PRECIPITATION WILL CHANGE OVER TO SNOW...UNCERTAINTY REMAINS
RATHER HIGH AS TO THE EXACT TIMING THIS MAY OCCUR ON WED. IF THE
HEAVY SNOW DOES MATERIALIZE...PERIODS OF IFR TO VLIFR VIS AND
CIGS WOULD BE LIKELY AT TIMES DURING THE DAY.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM ON CIG TRENDS.
* LOW TO MEDIUM ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND CHANGE OVER FROM RA TO SN.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM TUESDAY.
GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
535 AM CST Tue Dec 23 2014
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Backedge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 506 AM CST TUE DEC 23 2014
Model guidance continues to throw us curve balls on how the current
system will depart the area on Christmas Eve. Their spread in the
details and lack of run-to-run consistency continues to make our
confidence in Christmas Eve`s snow potential much lower than
average. There has been more than a trivial trend back toward a
snowier day in the latest runs, although this trend is far from
unanimous. The upshot is that that travel difficulties could exist
for Christmas Eve and it is prudent to monitor later forecasts
closely. While confidence is too low to issue any winter weather
headlines at this time, have issued a Special Weather Statement
highlighting the potential as well as the uncertainty.
However, the main snow threat is still a couple days off. Until
then, we will have to contend with periods of rain, although
confidence is growing that sizable breaks in the rainy periods will
occur. A dry slot wrapping around the vertically stacked
upper/surface low should support most of Tuesday, and even into
Tuesday evening, ending up dry. This dry slot is showing up nicely
as a nearly cloud free area over the central High Plains, although
we do not expect skies to be quite so clear by the time the drier
airmass arrives here. The initial upper/surface lows will dissipate
with time as a more vigorous wave rounds the base of the mean Plains
trof later Tuesday into Wednesday.
Our main snow concern arrives as the above mentioned wave heads
northeast, developing a new surface cyclone as it does so. While all
models still keep the track of the surface low east of the forecast
area, the track has shifted far enough west in most model solutions
that the deformation zone on its back side tracks across at least
east-central and southeast Illinois. However, a wide range of model
solutions exist in the timing, track, and precipitation intensity
within this deformation zone. It is also unclear if all the
precipitation within the deformation zone will fall as snow, or it
will fall as rain or a rain/snow mix for a time. Obviously, this is
critical to snow accumulation potential. While most guidance has
surface temperatures above freezing through Wednesday afternoon, the
"warm" air depth is very shallow, generally no more than 1000-1500
feet above the ground. If snowfall rates are high enough, they will
quickly be able to erode this warm layer. There are signs that
convective banding within the deformation zone is possible, which
would certainly provide high enough rates to support a quicker
change over to snow. In any event, due to the persistent
uncertainty, have gone with no more than an inch or two of snowfall
on the back side of the system, mainly east of I-55. If the latest
model trends hold, these totals will need to be boosted.
The next couple waves/precipitation threat have slowed a bit from
previous days, centering more on Saturday/Sunday than
Friday/Saturday time frame. Temperatures just ahead of the lead wave
support rain or a rain/snow mix, with conditions eventually cooling
enough for all snow. Precipitation amounts during this time appear
fairly minor for the moment.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 530 AM CST TUE DEC 23 2014
MVFR and local IFR cigs will become VFR this morning with PIA on
the edge of some wrap around moisture from the departing storm
system. Forecast soundings showing despite the loss of the low
level moisture, quite a bit of mid and high level cloud cover
will affect the TAF sites this morning into the afternoon hours
before more MVFR cigs approach the area for late this evening and
into the overnight hours ahead of the next storm system. As the
next storm system approaches from the south tonight, rain will
overspread the area from south to north after 04z with CMI and
DEC the first to see the rain followed by SPI and BMI aftr 06z
and then PIA during the early morning hours. Once the rain begins
it appears the cigs will quickly drop to MVFR and then eventually
IFR once again, but at this time will hold off bringing cigs and
or vsbys down too much in this forecast period as it appears the
IFR and LIFR cigs will be during the day Wed. Surface winds will
be out of the southwest today at 10 to 15 kts, and the gradually
turn into a light northwest to north direction tonight at 4 to
9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
219 AM CST TUE DEC 23 2014
.UPDATE...
850 PM CST
NO CHANGES PLANNED TO FORECAST FOR TONIGHT AS UPPER LOW TO OUR
WEST CONTINUES TO DUMBBELL SLOWLY NORTHEAST FROM THE CORN BELT
TOWARD WISCONSIN. ASSOCIATED SFC LOW OVER SOUTHERN IOWA WILL MOVE
NORTHEAST IN CONCERT WITH THE UPPER LOW AND DRAG A WARM FRONT
NORTH ACROSS THE CWA OVERNIGHT INTO EARLY TUESDAY MORNING. THE
RESULT DRIZZLE AND FOG OVERNIGHT PUNCTUATED WITH PERIODS OF RAIN
ALONG WITH SLOWLY RISING TEMPS AS THE DIFFUSE WARM FRONT LIFTS
SLOWLY NORTH. TRENDS IN THE GRIDS ALREADY HAVE A GOOD HANDLE ON
THIS AND NO CHANGES ARE PLANNED.
OF MUCH GREATER CONCERN CONTINUES TO BE THE POTENTIAL FOR A WINTER
STORM AFFECTING PORTIONS OF THE REGION WEDNESDAY...CHRISTMAS EVE
DAY. THE 00Z WRF-NAM IS TRICKLING IN AND APPEARS TO HAVE FINALLY
CAVED IN AND JOINED THE CAMP OF WHAT THE REMAINDER OF THE GLOBAL
MODELS HAD SHOWN ON WITH THE 12Z RUNS. LACK OF RUN-TO-RUN
CONSISTENCY AND HIGH DEGREE OF VARIABILITY BETWEEN VARIOUS MODELS
HAS MADE THIS A CHALLENGING SYSTEM TO FORECAST FOR...HOWEVER THE
12Z GLOBAL MODELS CAME INTO MUCH BETTER AGREEMENT AND NOW THE 00Z
WRF-NAM SEEMS TO HAVE JOINED THAT CAMP WHICH COULD POSE A
SIGNIFICANT WINTER STORM THREAT TO A POTENTIALLY LARGE PORTION OF
OUR CWA WEDNESDAY.
THE EXPLOSIVE DEEPENING OF THE SYSTEM PROGGED IN THE MODELS WITH
500MB...ALONG WITH AMPLE MOISTURE...AND ELEVATED INSTABILITY ALL
LEAVE ME VERY CONCERNED THAT WE COULD BE LOOKING AT A VERY HEAVY
AND WET SNOW AFFECTING THE REGION WEDNESDAY. THE NEGATIVE MID-
LEVEL THETA-E LAPSE RATES AND LAPSE RATES GREATER THAN 6C/KM FROM
600-300MB POINT TOWARD THE POTENTIAL FOR UPRIGHT CONVECTION WITHIN
THE DEFORMATION BAND. THERMAL PROFILES IN THE MODELS ARE MARGINAL
FOR SNOW...ESPECIALLY DOWN LOW...HOWEVER GIVEN THE EXTREMELY
IMPRESSIVE DYNAMICS SHOWN IN THE LATEST GUIDANCE WOULD ANTICIPATE
STRONG ASCENT TO OVERWHELM IN MARGINAL WARMTH DOWN LOW AND LIKELY
ALLOW FOR HEAVY WET SNOW IN THE DEFO BAND.
NOT UNCOMMON FOR RAPIDLY DEEPENING SYSTEMS TO TRACK A BIT FARTHER
WEST THAN MODELS FORECAST...WHICH COULD PUSH THE HEAVY SNOW BAND
FARTHER WEST IN OUR CWA WITH MORE OF A MIX EAST. THE STRONG
FRONTOGENETIC FORCING AND WEAK INSTABILITY WOULD FAVOR A RATHER
NARROW BUT INTENSE BAND OF PRECIPITATION...MAKING THE PLACEMENT OF
ANY HEAVY SNOW BAND VERY DIFFICULT TO PINPOINT.
AM RELUCTANT TO MAKE ANY WHOLE SALE CHANGES TO THE 4TH PERIOD OF
THE FORECAST ON AN EVEN SHIFT FOLLOWING A QUICK GLANCE AT THE
LATEST NAM...HOWEVER IF THE 00Z GLOBAL GUIDANCE COMES IN LOOKING
SIMILAR TO THEIR 12Z RUNS AND ANYTHING LIKE THE 00Z WRF-NAM THEN
THE MIDNIGHT SHIFT WILL PROBABLY NEED TO CONSIDER WINTER STORM
WATCH FOR AT LEAST PORTIONS OF THE AREA. WHILE IT LOOKS TO BE A
VERY HIGH WATER CONTENT SNOWFALL...THE CONVECTIVE ALLOWING MODELS
ARE SPITTING OUT QPF VALUES THAT COULD SUPPORT 6+ INCHES OF SNOW
EVEN WITH SNOW:LIQUID RATIOS AS LOW AS 7-8:1. WILL UPDATE THE SPS
AND HIT THINGS HARDER IN THAT PRODUCT FOR NOW.
IZZI
&&
.SHORT TERM...
1227 PM CST
TONIGHT THROUGH CHRISTMAS DAY...
MAIN CHALLENGES FOR TONIGHT WILL BE ON PLACEMENT OF PRECIP ALONG
WITH HOW MUCH RAIN WILL FALL ACROSS THE FORECAST AREA. THE
NORTHERN STREAM SFC LOW HAS BECOME WRAPPED UP ACROSS THE
DAKOTAS...WITH THE MID-LVL TROUGH AXIS STRETCHING SOUTH THROUGH
THE SOUTHERN PLAINS. LLVL FLOW ACROSS THE FORECAST AREA HAS BECOME
MORE EASTERLY...WITH A FEED OF SOME SLIGHTLY DRIER AIR AT THE SFC
INTO NORTHERN IL/NORTHWEST IN. THIS HAS BEEN ABLE TO DELAY THE
ONSET OF STEADY PRECIP UNTIL LATER THIS AFTN. SFC TEMPS HAVE BEEN
SLOW TO WARM...AND LATEST GUIDANCE INDICATES THAT MAX TEMPS MAY
NOT OCCUR UNTIL JUST AFT 00Z AS A STEADY CONVEYOR OF WARMER/MOIST
AIR ADVECTS NORTH.
LOCAL SOLUTIONS BRING THE BETTER SLUG OF PRECIP INTO THE FORECAST
AREA THIS EVENING...THEN SLOWLY LIFT THE STEADIER RAIN NORTH
OVERNIGHT. QPF TOTALS HAVE DECREASED FROM EARLIER SOLUTIONS...BUT
HAVE ONLY MADE MINOR ADJUSTMENTS TO THE GOING FORECAST. THE SFC LOW
OVER THE DAKOTAS WILL BE SLIDING SOUTHEAST TOWARDS SOUTHEAST IOWA
OVERNIGHT...WITH A DRY WEDGE BECOMING ENTRAINED OVER MISSOURI.
GUIDANCE HAS BEEN LEANING TOWARDS POSSIBLY AN EARLIER ARRIVAL OF THE
DRY SLOT INTO THE FORECAST AREA JUST BEFORE DAYBREAK TUE. GIVEN THE
CONTINUED UNCERTAINTIES ON TRACK/PLACEMENT OF THE LOW...HAVE HELD
ONTO SOME LGT RAIN AT DAYBREAK THEN LIFT THE PRECIP SHIELD NORTH OF
INTO WISC BY MID-MORNING TUE. TEMPS OVERNIGHT MON SHUD BE NEARLY
STEADY...THEN AFT MIDNIGHT WITH A 850MB THERMAL RIDGE OF 3-6 DEG C
LIFTING NORTH EXPECT TEMPS TO BE SLOWLY RISING INTO THE LOW 40S.
TUE EXPECT THE SFC LOW TO BE SLOWLY WEAKENING ACROSS SOUTHWEST
WISC...WITH THE MID-LVL TROUGH AXIS EJECTING THE SECONDARY SFC LOW
ALONG THE WESTERN GULF. THIS SECONDARY LOW IS THE MAIN CONCERN FOR
WED AFTN-WED NGT ACROSS OUR REGION. THE DRY WEDGE SHUD KEEP PRECIP
WEST/NORTH OF THE FORECAST AREA THRU TUE MORNING...THEN WRAP AROUND
MOISTURE WILL BRING LGT RAIN BACK INTO THE AREA TUE AFTN/EVE. TEMPS
SHUD WARM INTO THE MID/UPR 40S...POSSIBLY TOUCHING 50 DEGREES IN THE
SOUTHEAST CWFA. THE SOUTHERN STREAM LOW WILL BE RAPIDLY DEEPENING
AND LIFTING NORTH ACROSS THE TENN VALLEY WED MORNING...THEN IT
BECOMES A CHALLENGE ON THE PLACEMENT OF THE LOW BEYOND WED MORNING.
GUIDANCE CONTINUES TO SHOW CORRECTIONS...WITH A FEW SOLUTIONS
BRINGING THE LOW NORTH INTO NORTHEAST IN AND A FEW FURTHER EAST.
THIS WILL BE A KEY PLAYER ON THE PLACEMENT OF THE POTENTIAL
DEFORMATION ZONE WHICH COULD BRING ACCUM SNOW TO THE FORECAST AREA
WED AFTN/EVE. TEMPS WILL BE FALLING DURING THE DAY WED...AND WITH
THE INCREASED FORCING...THIS COULD BR STRONG ENOUGH TO OVERCOME THE
WARMER AIR AT THE SFC AND ALLOW RAIN TO QUICKLY CHANGE TO SNOW AND
START ACCUMULATING. GEFS ENSEMBLES ARE BEGINNING TO DEMONSTRATE A
WEAK EASTERLY LLVL JET AT 850MB LIFTING NORTHEAST OVER THE FORECAST
AREA WED AFTN/EARLY EVE...WHICH WOULD SUPPORT THE IDEA OF A
DEFORMATION SNOW BAND FOR THE CENTRAL/EASTERN CWFA. CONSIDERABLE
UNCERTAINTY REMAINS WITH THIS SYSTEM...BUT EITHER WAY IT WILL IMPACT
A PORTION OF THE GREAT LAKES REGION ON ONE OF THE BUSIEST TRAVEL
DAYS OF THE YEAR.
FOR CHRISTMAS DAY...THE DOWNSTREAM RIDGE OVER THE CANADIAN MARITIME
WILL BEGIN TO WEAKEN AND ALLOW FOR THE 500MB TROUGH TO PUSH EAST OF
THE GREAT LAKES...LIFTING THE DEEPER MOISTURE/PRECIP NORTHEAST WITH
IT. MOST GUIDANCE COMES INTO SLIGHTLY BETTER AGREEMENT FOR HIGHS
ARND THE MID/UPR 30S...WITH POSSIBLY THINNING CLOUD COVER.
BEACHLER
&&
.LONG TERM...
252 PM CST
FRIDAY THROUGH MONDAY...
MAIN FORECAST CONCERNS THIS PERIOD SURROUND A PAIR OF STORM SYSTEMS.
THE FIRST TO PASS TO THE NORTH OF THE AREA FRIDAY-FRIDAY NIGHT AND
THE SECOND TO PASS TO THE SOUTH AND EAST (SHOULD CURRENT TRENDS
CONTINUE) ON SUNDAY. FIRST SURFACE LOW DEVELOPS OVER THE CENTRAL
PLAINS THURS NIGHT IN RESPONSE TO THE DIGGING UPPER TROF OVER THE
WESTERN U.S. MODELS SHOWING NRN IL GENERALLY DRY FRIDAY DURING THE
DAYTIME HOURS FRIDAY WITH MAX TEMPS RUNNING AROUND 10 DEG ABOVE
AVERAGE. A COLD FRONT THEN SWEEPS ACROSS THE AREA FRIDAY NIGHT
BRINGING A CHANCE OF RAIN OR SNOW.
MEANWHILE A SECONDARY UPPER LEVEL SHORTWAVE ROTATES INTO THE BASE
OF WESTERN U.S. TROUGH THEN ON SATURDAY AMPLIFYING THE SOUTHERN
STREAM. MODELS NOT COMPLETELY RESOLVING THIS SYSTEM YET AND HAVE
LEANED TOWARD MODEL CONSENSUS FOR A FORECAST SCENARIO WHERE A
SHARPER SHORTWAVE HELPS TO ORGANIZE SURFACE LOW PRESSURE NEAR THE
TX/LA GULF COAST SATURDAY. THIS LOW THEN MOVES NORTHEAST ACROSS
THE TN VALLEY AND INTO THE CENTRAL APPLICATIONS SUNDAY. WILL
CONFINE POPS WITH THIS SYSTEM TO JUST THE SOUTHEASTERN COUNTIES OF
THE FORECAST AREA CURRENTLY WITH TEMPS EXPECTED NEAR SEASONAL FOR
THE TIME OF YEAR.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PRIMARILY IFR CIGS OVERNIGHT...PROBABLY LIFTING TO MVFR OR
POSSIBLY VFR DURING THE DAY.
* PERIODS OF RAIN/DRIZZLE OVERNIGHT THROUGH EARLY MORNING
KJB
//DISCUSSION...UPDATED 06Z...
A SURFACE LOW ACROSS IOWA WILL DRIVE A FRONTAL BOUNDARY NORTHWARD
ACROSS NORTHERN ILLINOIS BY DAYBREAK. ONCE THIS FRONT PASSES...THE
RAIN WILL COME TO AN END. IN FACT...CURRENT REGIONAL RADAR IMAGERY
ALREADY SHOWS THE LAST BATCH OF RAINFALL LIFTING NORTHWARD ACROSS
CENTRAL ILLINOIS. CURRENT TIMING PUTS THE BACK EDGE OF THIS RAIN
THROUGH MOST OF THE TERMINALS BY 10 UTC. CIGS LOOK LIKE THEY WILL
REMAIN IN THE 500 TO 700 FOOT RANGE FOR MUCH OF THE NIGHT.
HOWEVER...CIGS DO LOOK TO IMPROVE DURING THE DAY TODAY...POSSIBLY
TO VFR. OTHERWISE...EXPECT WINDS TO SHIFT SOUTH-SOUTHWESTERLY BY
DAY BREAK AS THE AFOREMENTIONED FRONTAL BOUNDARY LIFTS OVER THE
AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CIGS THROUGH TONIGHT...DECREASING CONFIDENCE
IN CIGS FORECAST TUESDAY
* MEDIUM-HIGH CONFIDENCE IN PRECIP TRENDS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...RAIN LIKELY...POSSIBLY CHANGING TO HEAVY WET SNOW. IFR
OR LOWER PROBABLE.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 908 PM CST MON DEC 22 2014
Most of forecast looks ok. However, will have to make some
adjustments to pcpn/pop and possibly low temps tonight. Back edge
of pcpn is on the Miss river and will continue to move northeast
overnight. So will be making minor changes to mentioned items shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST MON DEC 22 2014
Short-wave trough evident on 19z/1pm water vapor imagery over
Kansas/Oklahoma will lift northeastward tonight, reaching central
Illinois by 12z Tue. A large area of light rain associated with
this feature is currently ongoing across the KILX CWA: however,
radar imagery is showing the precip becoming more scattered upstream
across Missouri into southern Illinois. With a continued moist flow
and strong lift ahead of the upper wave, think numerous showers will
re-develop behind the main rain area later this afternoon into the
evening. As a result, will continue to carry categorical PoPs
across the board through the evening. After that, models agree that
a mid-level dry slot will approach from the southwest later tonight
into Tuesday morning. Both the 12z NAM and the 17z HRRR suggest the
showers will taper off and come to an end from southwest to
northeast across the area by dawn Tuesday. Will continue likely to
categorical PoPs along/north of I-74 through the entire night, but
will drop to just chance PoPs further south across the rest of the
CWA after midnight. Southerly winds of 10 to 15 mph will continue
tonight, preventing temps from dropping much. Overnight lows will
be several degrees above numeric guidance, ranging from around 40
across the north to the middle 40s south of I-70.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 259 PM CST MON DEC 22 2014
Model guidance continues to throw us curve balls on how the current
system will depart the area on Christmas Eve. Their spread in the
details and lack of run-to-run consistency continues to make our
confidence in Christmas Eve`s snow potential much lower than
average. There has been more than a trivial trend back toward a
snowier day in the latest runs, although this trend is far from
unanimous. The upshot is that that travel difficulties could exist
for Christmas Eve and it is prudent to monitor later forecasts
closely. While confidence is too low to issue any winter weather
headlines at this time, have issued a Special Weather Statement
highlighting the potential as well as the uncertainty.
However, the main snow threat is still a couple days off. Until
then, we will have to contend with periods of rain, although
confidence is growing that sizable breaks in the rainy periods will
occur. A dry slot wrapping around the vertically stacked
upper/surface low should support most of Tuesday, and even into
Tuesday evening, ending up dry. This dry slot is showing up nicely
as a nearly cloud free area over the central High Plains, although
we do not expect skies to be quite so clear by the time the drier
airmass arrives here. The initial upper/surface lows will dissipate
with time as a more vigorous wave rounds the base of the mean Plains
trof later Tuesday into Wednesday.
Our main snow concern arrives as the above mentioned wave heads
northeast, developing a new surface cyclone as it does so. While all
models still keep the track of the surface low east of the forecast
area, the track has shifted far enough west in most model solutions
that the deformation zone on its back side tracks across at least
east-central and southeast Illinois. However, a wide range of model
solutions exist in the timing, track, and precipitation intensity
within this deformation zone. It is also unclear if all the
precipitation within the deformation zone will fall as snow, or it
will fall as rain or a rain/snow mix for a time. Obviously, this is
critical to snow accumulation potential. While most guidance has
surface temperatures above freezing through Wednesday afternoon, the
"warm" air depth is very shallow, generally no more than 1000-1500
feet above the ground. If snowfall rates are high enough, they will
quickly be able to erode this warm layer. There are signs that
convective banding within the deformation zone is possible, which
would certainly provide high enough rates to support a quicker
change over to snow. In any event, due to the persistent
uncertainty, have gone with no more than an inch or two of snowfall
on the back side of the system, mainly east of I-55. If the latest
model trends hold, these totals will need to be boosted.
The next couple waves/precipitation threat have slowed a bit from
previous days, centering more on Saturday/Sunday than
Friday/Saturday time frame. Temperatures just ahead of the lead wave
support rain or a rain/snow mix, with conditions eventually cooling
enough for all snow. Precipitation amounts during this time appear
fairly minor for the moment.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1207 AM CST TUE DEC 23 2014
Clouds continue over the area with rain lifting north. Pcpn will
end, but with lower clouds, light pcpn could hang around for
awhile, so will keep VCSH at all sites overnight. Cig heights will
also lift some as well and become lower level MVFR overnight.
Satellite trends do show clearing across MO and based on HRRR
forecast the clearing gets into the area. But believe mid level
clouds will move into the area behind the clearing area. By
tomorrow afternoon, cigs will drop more and then finally drop back
to MVFR levels ahead of the next system. Winds will be southerly
overnight and then become light and variable tomorrow afternoon
and evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS DES MOINES IA
325 PM CST TUE DEC 23 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 313 PM CST TUE DEC 23 2014
PRECIP TRENDS WILL REMAIN THE PRIMARY FOCUS AGAIN TONIGHT. LIGHT
SNOW CONTINUES TO DRIFT NE-SW ACROSS THE NW HALF OF IA DRIVEN
MAINLY BY MID LEVEL KINEMATIC FORCING WITH WEAK DEFORMATION AND
DIFFERENTIAL POSITIVE VORTICITY ADVECTION NORTH OF IA PV ANOMALY
NOTED IN RAP ANALYSIS AND SUGGESTED BY PIVOT POINT IN WATER VAPOR
IMAGERY. THERE IS LITTLE THERMODYNAMIC COMPONENT AT THIS POINT.
PRECIP IS QUITE LIGHT WITH WEAK REFLECTIVITY...EVEN IN LONG
PULSE/VCP 31. WEBCAMS SHOW CURRENT VISIBILITY RESTRICTIONS ARE AS
MUCH DUE TO FOG AS SNOW WITH LITTLE SNOW NOTED. THIS WEAK FORCING
WILL REMAIN ESSENTIALLY STEADY STATE AS IT DRIFTS SLOWLY SOUTH AND
EAST THROUGH THE NIGHT BEFORE THE NEXT SHORT WAVE/PV ANOMALY
ROUNDS THE BASE OF THE TROUGH AND RE-ENERGIZES SYSTEM AGAIN TO OUR
SOUTH AND EAST TOWARD 12Z. SE FRINGE OF PRECIP SHIELD WILL BE A
RAIN/SNOW MIX WITH RAIN/SNOW LINE DRIFTING SE. ONLY LIGHT QPF
AMOUNTS AND TEMPERED SNOW RATIOS WILL RESULT ANY ADDITIONAL ACCUMS
BEING UNDER AN INCH AND MAINLY ON GRASSY OR ELEVATED SURFACES.
ROAD TEMPS REMAIN WET AND 35F PLUS SO MUCH OF SNOW WILL MELT ON
ROADS. MID LEVEL MOISTURE WILL BE LACKING SE WITH LITTLE ICE
INTRODUCTION SO PRECIP WILL GENERALLY REMAIN LIQUID/DRIZZLE SOUTH
AND EAST OF DES MOINES.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 313 PM CST TUE DEC 23 2014
THE LONG TERM PORTION OF THE FCST PD WILL BE CHARACTERIZED BY
MINIMAL PRECIPITATION...ALONG WITH ABOVE NORMAL TEMPERATURES LATE
THIS WEEK FOLLOWED BY TEMPERATURES GOING BELOW NORMAL BEGINNING
THIS WEEKEND AND CONTINUING INTO NEXT WEEK.
MODELS IN GOOD AGREEMENT WITH THE CENTRAL CONUS SHORTWAVE ENERGY
DEVELOPING A SFC LOW ACROSS THE SOUTHERN U.S. TONIGHT...BRINGING
IT NORTH-NORTHEAST INTO THE EASTERN GREAT LAKES AND DEEPENING BY
THURSDAY. GREATEST SYNOPTIC FORCING AND MOISTURE WILL REMAIN TO
THE EAST OF THE CWA. MODELS SHOWING REMNANT AREA OF WEAK LIFT AND
MOISTURE IN E/SE CWA THRU WED MORNING...SO HAVE KEPT CHC/SLIGHT
CHANCE POPS THERE. PCPN IS EXPECTED TO BE LIGHT.
ATTENTION THEN TURNS TO THE NEXT WX SYSTEM TO AFFECT OUR REGION.
CENTRAL U.S. SHORTWAVE LIFTS OUT AND ANOTHER SHORTWAVE ENTERS THE
WESTERN U.S. BY THURSDAY. MODELS BEGIN DIVERGING ON THE SPEED AND
STRENGTH OF THIS SHORTWAVE ONCE IT ARRIVES. GFS PRESENTS A FASTER
AND WEAKER SOLUTION...WITH THE ECMWF HOLDING THE ENERGY BACK FOR
LONGER. THE DIVERGING SOLUTIONS IMPACT SFC FEATURES AS WELL...WITH
THE GFS BRINGING A STRONGER SFC SYSTEM THROUGH OUR REGION AND
FASTER VS. THE ECMWF. HAVE TRENDED SLOWER THAN THE GFS GIVEN ITS
RECENT PERFORMANCE...BRINGING -SN INTO THE CWA BEGINNING 12Z FRI.
PRIOR TO THE PRECIP/S ARRIVAL...THOUGH...STRONG WAA WILL PUSH
THURSDAY/S MAXES INTO THE MIDDLE 30S AND 40S. ATTM THE BULK OF THE
PRECIP IS EXPECTED TO REMAIN NW OF THE CWA...WITH BEST COMBINATION
OF FORCING AND MOISTURE MOVING ACROSS THE CWA FRI AFTN AND FRIDAY
NIGHT. ALTHOUGH POPS ARE RELATIVELY LOW...THERE IS THE POTENTIAL
FOR A BRIEF PERIOD OF LIFT TO COINCIDE WITH ELEVATED RH LEVELS
WITHIN THE DGZ ESPECIALLY ACROSS NW IOWA.
MODEL SOLUTIONS DIVERGE FURTHER WITH TIME INTO THE WEEKEND SO
FORECAST CONFIDENCE DECREASES. GFS KEEPS OUR REGION IN CYCLONIC
FLOW WITH WEAK SHORTWAVES WHILE THE ECMWF BRINGS MORE FOCUSED
SHORTWAVE ENERGY THROUGH OUR REGION MONDAY. HAVE TENDED TOWARD THE
ECMWF AND HAVE SLIGHT CHANCE POPS FOR THIS TIME PD. LITTLE IF ANY
SNOWFALL ACCUMULATIONS ARE AGAIN EXPECTED GIVEN THE BEST FORCING
BEING OUT OF PHASE WITH ELEVATED MOISTURE LEVELS. TEMPERATURES
WILL BEGIN A DOWNWARD TEND AS NORTHWEST FLOW ALOFT PREVAILS.
&&
.AVIATION...23/18Z
ISSUED AT 1150 AM CST TUE DEC 23 2014
WIDESPREAD STRATUS AND VSBY RESTRICTIONS CONTINUE TO BLANKET TAF
SITES RANGING FROM MVFR SE TO IFR NW. PERSISTENT LIGHT SNOW IS
ALSO CONTRIBUTING TO VSBY REDUCTIONS SW-NE THROUGH KFOD/KMCW. CIG
SITUATION WILL CHANGE LITTLE THROUGH THE PERIOD WITH JUST SLIGHT
IMPROVEMENT TO MORE PREVALENT LOW END MVFR WED MORNING. AREA OF
LIGHT SNOW WILL GRADUALLY SHIFT SOUTH AND EAST AS WI SFC LOW FADES
AND IS REPLACED BY OH VALLEY LOW. ONLY -DZ IS ANTICIPATED AT KOTM
HOWEVER.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...ZOGG
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS JACKSON KY
429 PM EST TUE DEC 23 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM EST TUE DEC 23 2014
THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH AN AMPLIFIED LONG
WAVE PATTERN TO CONTINUE THROUGH THE PERIOD ACROSS THE CONUS. MODEL
DIFFERENCES CONTINUE HOWEVER TOWARDS THE LATTER HALF OF THE
PERIOD...AND HAVE SIDED MORE WITH THE ECMWF/CANADIAN SOLUTION GIVEN
THE OVERALL BETTER CONTINUITY.
DEEPER TROUGHING WILL BE MOVING OFF TO THE EAST ON THURSDAY...WITH
ANY LIGHT PRECIPITATION COMING TO AN END ACROSS EASTERN KENTUCKY BY
THE MORNING HOURS. DRY WEATHER WILL RETURN FROM THURSDAY AFTERNOON
THROUGH EARLY SATURDAY MORNING...AS RIDGING TAKES HOLD ACROSS THE
OHIO AND TENNESSEE VALLEYS. MEANWHILE...TROUGHING WILL BE REASSERT
ITSELF ACROSS THE ROCKIES...WITH A COLD FRONT MOVING INTO THE AREA
FOR THE WEEKEND.
THE GFS REMAINS PROGRESSIVE WITH THIS BOUNDARY...WHILE THE
ECMWF/CANADIAN ARE SLOWER AND ALLOW FOR MORE SOUTHERN STREAM
INTERACTION...PROLONGING THE PRECIPITATION CHANCES ALL THE WAY INTO
EARLY NEXT WEEK. AGAIN...AM INCLINED TO LEAN TOWARDS THE
ECMWF/CANADIAN SOLUTION AS THE GFS HAS TRENDED MORE AMPLIFIED WITH
THE UPPER LEVEL PATTERN FROM 24 HOURS AGO. AS SUCH...HAVE FOLLOWED
SUIT WITH THE GIVEN BLENDED GUIDANCE AND ALLOWED FOR LIKELY POPS
BY SUNDAY...AND THEN LOWER CHANCES INTO EARLY NEXT UNTIL SOME OF THE
DETAILS CAN BE IRONED OUT. THE FORECAST TEMPERATURE PROFILES SUPPORT
MORE RAIN THEN SNOW THROUGH WEEKEND...AND THEN PERHAPS A SNOWIER
FINISH AS WE HEAD INTO TUESDAY DEPENDING HOW MUCH COLDER AIR ACTUALLY
MAKES IT IN.
FOR TEMPERATURES...GENERALLY ABOVE NORMAL READINGS LOOK ON TAP
THROUGH THE WEEKEND...WITH NEAR TO COOLER THAN NORMAL VALUES BY EARLY
NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EST TUE DEC 23 2014
THIS AFTERNOON MOST SPOTS ARE DRY...HOWEVER SHOWERS AND EVEN A FEW
THUNDERSTORMS ARE MOVING NE OUT OF MIDDLE TN. THESE SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO SLOWLY PROGRESS NE OVER THE NEXT FEW
HOURS AND AFFECT SME AND LOZ FIRST. THESE SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH THE DAY INTO THE
OVERNIGHT. MOST AREAS THIS AFTERNOON HAVE BEEN BETWEEN VFR/MVFR CIGS
AND THIS WILL TREND TOWARD MVFR AND EVEN CLOSER TO IFR OVER MUCH OF
THE TAF PERIOD AS WE SEE MULTIPLE ROUNDS OF SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS. HEAVIER SHOWERS COULD ALSO BRIEFLY REDUCE VIS TO
NEAR IFR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
355 PM EST TUE DEC 23 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EST TUE DEC 23 2014
THIS AFTERNOON MOST SPOTS ARE DRY...HOWEVER SHOWERS AND EVEN A FEW
THUNDERSTORMS ARE MOVING NE OUT OF MIDDLE TN. THESE SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO SLOWLY PROGRESS NE OVER THE NEXT FEW
HOURS AND AFFECT SME AND LOZ FIRST. THESE SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH THE DAY INTO THE
OVERNIGHT. MOST AREAS THIS AFTERNOON HAVE BEEN BETWEEN VFR/MVFR CIGS
AND THIS WILL TREND TOWARD MVFR AND EVEN CLOSER TO IFR OVER MUCH OF
THE TAF PERIOD AS WE SEE MULTIPLE ROUNDS OF SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS. HEAVIER SHOWERS COULD ALSO BRIEFLY REDUCE VIS TO
NEAR IFR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
103 PM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1020 AM EST TUE DEC 23 2014
SATELLITE THIS MORNING SHOWING A FEW BREAKS IN THE CLOUDS
PARTICULARLY ACROSS SE PORTIONS OF THE CWA. ALSO SEEING A FEW SHOWERS
MOVING ALONG THE WESTERN CWA BORDER. CLOUDS AND SHOWERS EXPECTED TO
INCREASE THROUGH THE DAY TODAY. EVEN SLIGHT CHANCE OF A THUNDERSTORM
ONCE WE MOVE INTO THE AFTERNOON HOURS FROM SW TO NE. NO MAJOR CHANGES
MADE THIS UPDATE. DID FRESHEN UP THE GRID WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EST TUE DEC 23 2014
THIS AFTERNOON MOST SPOTS ARE DRY...HOWEVER SHOWERS AND EVEN A FEW
THUNDERSTORMS ARE MOVING NE OUT OF MIDDLE TN. THESE SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO SLOWLY PROGRESS NE OVER THE NEXT FEW
HOURS AND AFFECT SME AND LOZ FIRST. THESE SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH THE DAY INTO THE
OVERNIGHT. MOST AREAS THIS AFTERNOON HAVE BEEN BETWEEN VFR/MVFR CIGS
AND THIS WILL TREND TOWARD MVFR AND EVEN CLOSER TO IFR OVER MUCH OF
THE TAF PERIOD AS WE SEE MULTIPLE ROUNDS OF SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS. HEAVIER SHOWERS COULD ALSO BRIEFLY REDUCE VIS TO
NEAR IFR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
1020 AM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1020 AM EST TUE DEC 23 2014
SATELLITE THIS MORNING SHOWING A FEW BREAKS IN THE CLOUDS
PARTICULARLY ACROSS SE PORTIONS OF THE CWA. ALSO SEEING A FEW SHOWERS
MOVING ALONG THE WESTERN CWA BORDER. CLOUDS AND SHOWERS EXPECTED TO
INCREASE THROUGH THE DAY TODAY. EVEN SLIGHT CHANCE OF A THUNDERSTORM
ONCE WE MOVE INTO THE AFTERNOON HOURS FROM SW TO NE. NO MAJOR CHANGES
MADE THIS UPDATE. DID FRESHEN UP THE GRID WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM EST TUE DEC 23 2014
A MIX OF VFR/MVFR CONDITIONS WILL BE SEEN OVER THE NEXT 12 TO 24
HOURS AS A NUMBER OF WEAK DISTURBANCES PUSH NORTH AHEAD OF AN UPPER
LEVEL TROUGH ADVANCING FROM THE WEST. SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE DAY TODAY...WITH THE BEST CHANCES FOR MORE
WIDESPREAD RAIN COMING LATER THIS EVENING. A DAMP NIGHT IS ON TAP FOR
TONIGHT AS MORE RAIN CONTINUES TO SPREAD NORTHWARD ACROSS THE AREA.
THIS WILL KEEP CIGS LOCKED AT MVFR LEVELS PERHAPS GETTING CLOSE TO
IFR. SOME REDUCED VISIBILITIES WILL ALSO BE LIKELY WITH THE HEAVIER
RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
638 AM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM EST TUE DEC 23 2014
A MIX OF VFR/MVFR CONDITIONS WILL BE SEEN OVER THE NEXT 12 TO 24
HOURS AS A NUMBER OF WEAK DISTURBANCES PUSH NORTH AHEAD OF AN UPPER
LEVEL TROUGH ADVANCING FROM THE WEST. SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE DAY TODAY...WITH THE BEST CHANCES FOR MORE
WIDESPREAD RAIN COMING LATER THIS EVENING. A DAMP NIGHT IS ON TAP FOR
TONIGHT AS MORE RAIN CONTINUES TO SPREAD NORTHWARD ACROSS THE AREA.
THIS WILL KEEP CIGS LOCKED AT MVFR LEVELS PERHAPS GETTING CLOSE TO
IFR. SOME REDUCED VISIBILITIES WILL ALSO BE LIKELY WITH THE HEAVIER
RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1212 AM EST Tue Dec 23 2014
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1000 PM EST Mon Dec 22 2014
Good area of rain continues to move northeast over west-central to
north-central KY and south-central IN at this time. This is in
response to strong shortwave tilting negatively to the south and
east of main upper low over central Plains. This shortwave trough
over MO will lift rapidly northeast overnight. The trough is
enhancing forcing over the lower Ohio Valley. Looking at model
soundings and Nashville`s 00 UTC observed sounding, there is a bit
of elevated instability. The combination of forcing and less stable
air aloft is leading to good ascent ahead of the shortwave and the
area of rain, some moderate to isolated heavy, in our forecast area.
As the shortwave lifts northeast, so will the rain. Given the weak
instability aloft and given a few specks of 50 dBZ on radar here and
there, plus a few lightning strikes earlier, will include a slight
chance of thunder overnight, also supported by a 40 kt low-level
jet. Will carry categorical POPs with this feature overnight but
rain should then diminish somewhat toward morning, as supported by
latest HRRR run and as suggested by 00z NAM. Nevertheless, scattered
showers still are expected. Temps won`t dip much overnight, perhaps
a couple degrees then steady. Showers should then pick up again
during the day on Tuesday over central KY.
Issued at 650 PM EST Mon Dec 22 2014
Quick update for latest trends. Central KY and south-central IN has
been largely devoid of precip other than a few sprinkles early this
evening. However, better area of showers is developing and moving
northeast over western parts of KY and TN at this time, with some
briefly heavier cells. This is in response to forcing associated
with tail end of shortwave trough entering MO as the trough rotates
around the underside of the upper low over the central Plains.
As this shortwave moves northeast tonight, the area of showers will
lift northeast as well, spreading across the western half of our
forecast area. The Bluegrass region may stay on eastern fringe of
precip with only scattered showers. Surface winds will pick up a bit
this evening as well, especially along the I-65 corridor in response
to the shortwave rotating through to our west and northwest. This
will keep temps pretty much in check this evening.
.SHORT TERM (Now through Tuesday Night)...
Issued at 310 PM EST Mon Dec 22 2014
Deep upper low is just about to close off over the Northern Plains
this afternoon, with deep=layer S-SW flow increasing over the
Mississippi and Ohio Valleys. This pattern will result in mild but
unsettled weather over the next 36 hrs or so, as a series of
disturbances will touch off rounds of showers.
Moisture transport is just getting established, so the main precip
shield associated with the lead disturbance has remained confined
mainly to the Wabash Valley and points west, with very little in the
way of precip over central Kentucky or southern Indiana. A
smattering of showers did develop over northern Alabama, but not
showing much organization as it lifts through Middle Tennessee.
Still expecting precip to blossom tonight as additional upper waves
interact with a 40-45 kt low-level jet, but QPF looks fairly modest.
Therefore will still carry categorical POPs, even though confidence
in getting any substantial rain amounts is decreasing. An isolated
rumble of thunder still can`t be completely ruled out, but continues
to look less likely as this system appears to come at us in pieces.
Therefore will go forward without mention of thunder at this time.
By daybreak the best feed of deep moisture will be shunted to our
north and east, so would expect a break of a few hours in the precip
Tuesday morning. However the next wave will take shape late in the
day, spreading rain back in from south to north late afternoon/early
evening. Deepening surface low still progged to run up between the
I-65/I-75 corridors, with tremendous bust potential depending on
exactly where it tracks. Categorical POPs and steady temps in the
50s along/east of the track, while farther west, precip chances are
barely 50-60% and temps could drop into the lower 40s by Wednesday
morning. There will be a tight gradient in between but the placement
is a little iffy, and for now we will assume that to be somewhere
near I-65.
.LONG TERM (Wednesday through Monday)...
Issued at 300 PM EST Mon Dec 22 2014
An active long term period with the main forecast challenge being
temperatures and precipitation timing/types Christmas Eve through
Christmas morning, followed by more precipitation chances this
weekend.
The 22.12z guidance is trending toward a similar solution with the
main surface low track Wednesday morning. Outside of the NAM, which
was an eastern outlier, the ECMWF/GFS/GEM show a strengthening low
lifting along a Nashville to Louisville to Indianapolis track during
the course of the day. A time trend analysis shows this is a slight
shift west and about 3-6 hours later than the previous consensus.
The impacts this has to precipitation timing and type were very
minimal, as there has been good consensus for steady rain to move
across the region during the course of the day. However, the change
does allow for warmer air to move through central/eastern Kentucky
and as a result, high temperatures were increased to the mid/upper
50s from the Cumberland to Bluegrass region, including the Lexington
metro area. For the Louisville area, the tighter baroclinic zone
will be right along the I-65 corridor, making Wednesday morning
temperatures difficult to pinpoint at this time. Nonetheless, the
area should warm into the low 50s before cold advection kicks in and
temperatures crash into the low/mid 40s by afternoon. Western
forecast area should see the coolest readings, likely stuck in the
upper 40s, then falling into the upper 30s by mid afternoon.
The main message/impact for the public will be a wet, unsettled
Christmas Eve with falling temperatures during the afternoon. It`ll
also be windy, both ahead and behind the surface low. Not ideal
holiday travel conditions, even if it`s just all liquid.
Soundings show a potential changeover from rain to snow west of I-65
during the evening hours /after 7 pm/. However, the greater
frontogenetical forcing and deformation precipitation band should be
west of the forecast area and we`ll be dealing with scattered, light
precipitation. Will continue to advertise a rain to rain/snow mix to
light snow during the nighttime hours. Little accumulations likely
as wet/warm surfaces and temperatures in the low/mid 30s will limit
accumulations. For Christmas, plan on clearing skies west to east as
a Pacific airmass high pressure quickly builds in from the
southwest. Temperatures will be around normal in the mid 40s.
The weekend forecast has some uncertainty as the whole upper level
flow remains amplified and active across the CONUS. At least
initially, there is some consensus that a surface low lifts through
the Great Lakes Friday night, dragging a cold front through the
local area Saturday. 30-40 percent rain chances look reasonable at
this time. Differences arise between the ECMWF/GFS/GEM as the 22.12z
ECMWF/GEM camp develop a secondary low along the Texas gulf coast
Saturday night, lifting it toward eastern Tennessee Sunday. This
would spread precipitation back across the area. Temperature
profiles this time would support a rain/snow mix for the northwest
half of the forecast area. However, the forecast details, including
any specific storm system/track, beyond Saturday have low confidence
as there are a wide range of solutions in this type of upper level
pattern. Next week looks to featuer similar uncertainity as both
ECMWF and GFS show varying storm systems to possibly impact the
area. An active stretch through the end of the year.
&&
.AVIATION (06Z TAF Update)...
Issued at 1209 AM EST Tue Dec 23 2014
Showers will continue off and on through this TAF period. Through
this morning a shortwave will continue to lift off to the northeast. Winds
at 2 kft will continue to increase to around 40 knots. Though it
will be marginal, have decided to keep LLWS in the TAFs for SDF and
BWG through 09-10Z. Winds aloft will decrease thereafter.
The other challenge for this forecast will be ceilings and
visibility. Visibility will likely bounce between VFR and MVFR as
multiple waves of showers cross the TAF sites. Guidance suggests
that ceilings will continue to lower overnight. SDF and particularly
BWG will likely drop to IFR. Some improvement will be possible at
SDF through the day, but BWG looks to remain IFR throughout after it
drops. LEX is more questionable, so have kept cigs more optimistic
there.
Winds will decrease through the morning hours to less than 7 knots.
An increase is then expected again tonight as a low approaches from
the south.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........TWF
Short Term.....RAS
Long Term......ZBT
Aviation.......EER
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
940 PM EST WED DEC 24 2014
.SYNOPSIS...
STRENGTHENING LOW PRESSURE WILL LIFT INTO THE GREAT LAKES
TONIGHT...BRINGING A COLD FRONT ACROSS THE REGION. MILD SOUTHERN
HIGH PRESSURE WILL MOVE IN FOR THE END OF THE WEEK. A WEAK COLD
FRONT WILL PUSH IN FROM THE NORTHWEST SUNDAY. THEN...LOW PRESSURE
FROM THE DEEP SOUTH WILL RIDE UP ALONG THAT FRONT AND OVER THE
REGION EARLY NEXT WEEK. COLDER HIGH PRESSURE WILL FOLLOW FOR MID
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
02Z WATER VAPOR IMAGERY INDICATING CENTER OF SFC LOW PIVOTING
THROUGH GREAT LAKES REGION...WITH ASSOCIATED COLD FRONT EXTENDING
SOUTH OVER WESTERN PA/CENTRAL WV. WARM FRONT SITUATED TO THE EAST
NOW...TAKING THE LIGHT RAIN WITH IT. MOIST AIRMASS IN PLACE HAS
RESULTED IN WIDESPREAD FOG WITH AREAS OF DENSE FOG MAINLY EAST OF
BLUE RIDGE. CONTINUING DENSE FOG ADV HERE TO ACCOUNT FOR VIS BEING
REDUCED TO 1/4 MILE OR LESS. AS THE PCPN MOVES IN...ENOUGH MIXING
SHOULD OCCUR TO IMPROVE VIS TO AT LEAST A MILE OR MORE.
A LINE OF SHOWERS WITH EMBEDDED HEAVIER SHOWERS NOTED RIGHT ALONG
THE COLD FRONT. ISO SVR TSTMS HAD BEEN OBSERVED IN THE LINE
EARLIER THIS EVENING...BUT WITH LOSS OF ANY INSTABILITY...WHICH
WAS MINIMAL TO BEGIN...NOT ANTICIPATING ANY THUNDER TO EXTEND INTO
OUR CWA. MATCHING WITH LATEST HRRR RUN AND TIMING OF THE
RADAR...STEP THE PCPN ACROSS DURING THE OVERNIGHT HOURS. HRRR ALSO
SUGGESTIVE OF A BIG WAVE OF PCPN COMING UP FROM THE SOUTH AHEAD OF
THIS LINE. WITH THE MOISTURE IN PLACE AND DECENT FORCING ALOFT NOT
QUESTIONING THE FORMATION OF THESE SHOWERS...JUST THE
INTENSITY/COVERAGE. AS SUCH...KEPT LIGHT SHOWER MENTION...WITH THE
PCPN TAPERING OFF FROM THE WEST THROUGH THE DAYLIGHT HOURS.
EXPECTING ALL PCPN TO HAVE CLEARED THE AREA BY 12Z.
ANOTHER CONCERN FOR THE NIGHT IS A WIND ADVISORY IN PLACE FOR THE
POTOMAC HIGHLANDS. STRONG LLJ EXPECTED TO MOVE WITH WINDS AT 850MB
45-55 KTS. WITH THE HIGHER ELEVATIONS...COULD SEE SOME OF THESE
STRONGER WINDS IMPACT THE AREA. WOULD ALSO LIKE TO NOTE THE
HEAVIER SHOWERS MOVING THROUGH WITH THE COLD FRONT COULD BRING
DOWN HEAVIER GUSTS. RIGHT NOW THE ADVISORY GOES THROUGH 11Z...BUT
COULD VERY WELL SEE IT END SOONER WITH THE STRONGEST LLJ WINDS
LOOKING TO MOVE THROUGH THAT AREA BY 08Z.
BREEZY CONDS WL RESIDE BHD CDFNT...W/ BETTER MIXING IN PLACE. SOURCE
RGN OF AMS NOT THAT COLD...AND WL HV DOWNSLOPING WNDS. THEREFORE...MAXT
TMRW SHUD BE SIMLR TO TDA...OR PERHAPS A PINCH WARMER. MRNG CLDS
FM PVA WL QUICKLY ERODE. MOSUN FOR THE REST OF THE DAY.
UPSLOPE CONDS GOOD FOR CONTD CLDCVR ALONG THE WRN SLOPES...BUT LACK
OF MSTR NOT FVRBL FOR PRODUCING PCPN. MTN POPS THU STILL CAPPED AT
CHC...AND HV PTYPE MIX RA/SN.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AFTER THE MULTI-DAY PERIOD OF INFLUENCE FROM ANOTHER MONSTROUSLY
LARGE LOW PRESSURE SYSTEM...BY THURS NIGHT - WE WILL BE ON THE CUSP
OF A MULTI-DAY REPRIEVE...AT LEAST A COUPLE OF DAYS. IN THE WAKE OF
THE EXITING LOW...SFC HIGH PRESSURE WILL BUILD IN TO OUR SOUTH...
WHICH IS AN IMPORTANT KEY BECAUSE IT WILL SPREAD WARMER TEMPS UP THE
ERN SEABOARD INTO THE WEEKEND. FRIDAY WILL BE CLEAR AND QUIET. AFTER
A BREEZY/WINDY THURSDAY...WINDS WILL DROP OFF TO A LIGHT SLY FLOW.
ALTHOUGH NOT AN INCREDIBLY WARM DAY...MAX TEMPS ON FRI SHOULD REACH
5-10F ABOVE AVG FOR LATE DEC.
WHILE THE HIGH ROLLS OFF THE CAROLINA COAST INTO SATURDAY...SLY FLOW
WILL AGAIN BRING IN SLIGHTLY WARMER AIR W/ MAX TEMPS A BIT HIGHER
THAN FRIDAY...TOPPING OUT IN THE M-U50S. ANOTHER LOW PRESSURE WAVE
WILL SET UP OVER THE SRN PLAINS/LOWER MS VLY. GULF COAST MOISTURE
WILL AGAIN BE TAPPED FOR THE EARLY STAGES OF THIS NEXT SYSTEM...BUT
IN TERMS OF NORTHWARD EXTENT - IT WILL HAVE TROUBLE W/ SECONDARY
WAVES COMING IN FROM THE NW. 12Z RUNS OF THE GFS/EURO ARE IN THE
CLOSEST ALIGNMENT W/ EACH OTHER IN THE PAST FEW DAYS AS TO THE
INTERACTIONS/PROGRESSIONS OF THESE FEATURES. A STRONG ENOUGH UPPER
JET WILL TRANSPORT THE SHEARED EDGE OF THE GULF MOISTURE UP ACROSS
THE UPPER MIDWEST LATE SAT NIGHT. HOWEVER...A POTENT UPPER LOW
SLIDING JUST SOUTH OF HUDSON BAY WILL TAKE THIS NRN MOISTURE UP AND
OVER THE REGION BEFORE THE SRN SYSTEM CAN GET FULLY ORGANIZED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL HANG ON INTO
SATURDAY NIGHT. DRY CONDITIONS WILL LINGER. THERE IS A CHANCE FOR
A FEW UPSLOPE SNOW SHOWERS IN THE HIGHER PARTS OF THE POTOMAC
HIGHLANDS. JUST TWENTY FOUR HOURS AGO...THE EURO AND GFS MODELS
WERE BOTH HINTING OF A COLD FRONTAL PASSAGE SATURDAY INTO SATURDAY
NIGHT. SINCE THEN...BOTH MODELS HAVE BACKED OFF ON THIS IDEA.
THE COLD FRONT SHOULD PUSH ACROSS THE AREA SUNDAY BEFORE SLIDING TO
THE SOUTH AND STALLING ACROSS THE CAROLINAS BY SUNDAY NIGHT. SOME
LIGHT STRATIFORM RAIN WILL ACCOMPANY THE FRONT SUNDAY AND INTO
MONDAY WITH THE FRONT JUST TO OUR SOUTH. THE 00Z EURO MODEL STILLS
WANTS TO HANG ONTO THE IDEA OF A LOW DEVELOPING ALONG THE STALLED
FRONT BUT NOW THE GFS JUST WANTS TO PUSH ELONGATED STRANDS OF ENERGY
ALONG THE SURFACE FRONT AND OUT TO SEA. CONSIDER THIS...HIGH
UNCERTAINTY ON WHETHER WE SEE ADDITIONAL PERIODS OF LIGHT RAIN OR
PERHAPS LIGHT SNOW IN OUR CWA BY MONDAY NIGHT.
THERE IS A SLIGHT CHANCE OF SOME DEPARTING RAIN OR SNOW SHOWERS
TUESDAY...SHOULD A LOW DEVELOP ALONG THE FRONT. OTHERWISE...DRY
CONDITIONS WILL BE BROUGHT ABOUT WITH HIGH PRESSURE BUILDING LATER
TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
IFR OR LOWER CONDITIONS THIS EVENING AHEAD OF APPROACHING FRONT.
LIFR CIGS ACROSS THE AREA THRU AT LEAST 05Z. CURRENTLY HAVE CIGS
IMPROVING TO IFR OR MVFR AS THE FRONT/SHOWERS MOVE THRU.
HOWEVER...IMPROVEMENT TIME COULD BE 2-3 HOURS LATER THAN IN TAF.
NOT EXPECTING VFR TILL LATE TONIGHT. LOW CONFIDENCE ON TIMING OF CIGS.
VIS VARYING FROM LESS THAN 1 MILE TO 3 MILES ACROSS THE TAF
SITES. WILL KEEP VIS DOWN THROUGH THE NIGHT TILL FROPA...IMPROVING
TO P6SM LATE TONIGHT. THE 1 MILE OR LESS COULD CONTINUE 1-2 HOURS
LATER THAN IN TAF.
HIGHEST CONFIDENCE IN FORECAST IS WINDS...SLY FLOW THIS
EVENING...BCMG SW THEN W OVERNIGHT WITH FROPA. PSBL OCNL GUSTS
WITH W FLOW LATE TONIGHT...THEN MORE PERSISTENT GUSTS 20-25 KTS
DURING THE DAY TOMORROW. VFR CONDITIONS AS WELL THRU THE DAY WITH
SCT CU.
HIGH PRESSURE BUILDS IN AS THE POTENT LOW PRESSURE SYSTEM MOVES OFF
THE COAST LATE THU. THE HIGH WILL KEEP CONDITIONS QUIET/SOLID VFR
INTO THE WEEKEND.
&&
.MARINE...
WINDS SLOW TO INCREASE THIS EVENING ON THE WATERS WITH QUITE A
STABLE AIRMASS IN PLACE. OCNL GUSTS TO 17-18 KTS MAINLY OVER THE
SOUTHERN WATERS...BUT OTHERWISE...NOT QUITE AT SCA YET.
HOWEVER...EXPECTING A STRONG LLJ TO MOVE OVER THE WATERS THROUGH
THE OVERNIGHT...WHICH COULD SEE ENOUGH ENERGY MIX DOWN TO RESULT
IN GUSTS TO 20 KTS. HIGHER CONFIDENCE OF SCA EXISTS THOUGH IN THE
WAKE OF THE COLD FRONT THURS.
CDFNT E OF WATERS BY THU. WHILE GLW CONDS NOT OUT OF THE QSTN...IT
WUD TAKE IDEAL MIXING. STICKING W/ MEAN MIXED LYR...AND CARRYING SCA
THRU THE DAY.
LIGHT WINDS TO CLOSE OUT THE WEEK AS A LARGE SFC HIGH DEVELOPS TO
OUR SOUTH AND CALMS DOWN THE AREA WIND FIELD. SLY CHANNELING
POSSIBLE INTO LATE SAT W/ THE HIGH MOVING OFF THE COAST AND ANOTHER
LOW PRESSURE SYSTEM APPROACHING FROM THE WEST.
&&
.TIDES/COASTAL FLOODING...
TIME OF HIGH TIDE HAS PASSED FOR LOWER CHESAPEAKER BAY WITH WATER
LEVELS SLOWLY COMING DOWN NOW. AS OF 7 PM...LEVELS BELOW ANY
FLOODING THRESHOLDS SO ALLOWED THE ADV TO EXPIRE THERE. CONTINUING
NORTHERN CHESAPEAKE BAY WESTERN SHORE AS ANNAPOLIS CURRENTLY
SHOWING IN SOLID MINOR LVLS...AND THE REMAINING AREAS EXPECTING TO
REACH MINOR LVLS WITH 1.5 FT ANOM PSBL.
A COLD FRONT CROSSES THE WATER TONIGHT. DIRECTION NOT ALL THAT
GREAT FOR BLOWOUT CONDITIONS. WE WILL NEED TO SEE HOW MUCH WATER
IS TRULY PUSHED OUT. MAY NEED AN ADVISORY FOR ANOTHR CYCLE...ESPECIALLY
MID BAY. ON THE FLIP SIDE...THE AM CYCLE IS THE LOWER OF THE TWO
ASTRONOMICALLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...DENSE FOG ADVISORY UNTIL 1 AM EST THURSDAY FOR DCZ001.
MD...DENSE FOG ADVISORY UNTIL 1 AM EST THURSDAY FOR MDZ004>006-011-
013-014-016>018-503>508.
WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MDZ501.
COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ011-
014-508.
VA...DENSE FOG ADVISORY UNTIL 1 AM EST THURSDAY FOR VAZ052>057-505-
506.
WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ503-504.
WV...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ501>503-505-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1222 PM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1220 PM EST TUE DEC 23 2014
EXPECT LIFR/VLIFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD AT ALL
3 TAF SITES. GUSTY ENE WINDS MAY CAUSE ENUF BLSN AT THE EXPOSED CMX
LOCATION TO CAUSE VSBYS THERE TO FALL TOWARD VLIFR AS
WELL...ESPECIALLY IN THE EARLY AFTN WHEN STRONGER DYNAMIC FORCING WL
IMPACT THAT LOCATION. THE DISTURBANCE/DEEP MSTR WL EXIT LATE TODAY/
TNGT...SO THE SN WL DIMINISH. BUT LINGERING ALBEIT WEAKENING CYC NNE
FLOW OFF LK SUP WL MAINTAIN OVC LO CLDS/LIFR CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 644 AM EST TUE DEC 23 2014
EXPECT LIFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD AT ALL 3 TAF
SITES AS A STRONG DISTURBANCE MOVING THRU THE GREAT LKS BRINGS SOME
SN TO THE AREA TODAY. SINCE IWD WILL BE FARTHER FROM THE TRACK OF
THIS SYSTEM AND THE LLVL ENE WIND INITIALLY DOES NOT PRESENT A SGNFT
UPSLOPE COMPONENT...CONDITIONS THERE EARLY IN THE TAF PERIOD WILL BE
MVFR. BUT AS THE LLVL WINDS SHIFT TOWARD A MORE FAVORABLE UPSLOPE NE
DIRECTION AND DEEPER MSTR/HEAVIER SN ARRIVES BY AFTN...CONDITIONS
THERE SHOULD FALL TO LIFR AS WELL. THE BEST CHANCE FOR LOWER VSBYS
APRCHG VLIFR WL BE SAW LATE THIS MRNG INTO EARLY AFTN AS A BAND OF
VERY HEAVY SN CLOSER TO THE TRACK OF THE RESPONSIBLE DISTURBANCE
MOVES OVHD. GUSTY ENE WINDS MAY CAUSE ENUF BLSN AT THE EXPOSED CMX
LOCATION TO CAUSE VSBYS THERE TO FALL TOWARD VLIFR AS WELL...
ESPECIALLY IN THE EARLY AFTN WHEN THE STRONGER DYNAMIC FORCING WL
IMPACT THAT LOCATION. THE DISTURBANCE/DEEP MSTR WL EXIT LATE TODAY/
TNGT...SO THE SN WL DIMINISH. BUT LINGERING ALBEIT WEAKENING CYC NNE
FLOW OFF LK SUP WL MAINTAIN OVC LO CLDS/LIFR CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING NORTHEAST TOWARDS THE
AREA. THERE WILL LIKELY BE TWO SURGES OF PRECIPITATION WITH THIS
LOW...THE FIRST COMING DURING THE OVERNIGHT HOURS AND THE SECOND
ARRIVING BY LATE MORNING OR EARLY AFTERNOON. THE SECOND WAVE WILL
PRODUCE THE HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 511 PM EST MON DEC 22 2014
HIGHS WILL REMAIN IN THE 30S THROUGH THE DAY FRIDAY...WITH PLENTY OF
GOING ON PRECIP WISE THIS PERIOD. SLUSHY TO WET ROADWAYS WILL GREET
HOLIDAY TRAVELERS THROUGH FRIDAY...UNLESS A QUICK BURST OF SNOW
OCCURS.
INITIALLY HAVE THE EXITING SFC LOW SHIFTING FROM WI AT 00Z
WEDNESDAY...SHIFTING ACROSS LAKE MI OVERNIGHT INTO
WEDNESDAY...BECOMING A PART OF THE NEXT LOW NEARING FROM THE TN
VALLEY WEDNESDAY MORNING. DRIZZLE/FREEZING DRIZZLE WILL LINGER
THROUGH WEDNESDAY OVER THE E THIRD OF THE CWA...BEFORE CHANGING TO
SNOW LATE IN THE DAY.
ALTHOUGH THERE ARE STILL SOME DISCREPANCIES IN EVEN THE WEDNESDAY
NIGHT FCST...I DID TAKE OUT THE MENTION OF THE LOW PUSHING NORTHWARD
OVER E LOWER MI AND LAKE HURON LATE WEDNESDAY INTO WEDNESDAY EVENING
FOR THE EAST HALF OF UPPER MICHIGAN IN THE HWO. THE 22/00Z ECMWF IS
STRONGER/MORE WRAPPED UP...AND AS A RESULT KEEPS WRAP AROUND PRECIP
WEDNESDAY NIGHT INTO THURSDAY OVER OR JUST E OF THE CWA. THE 22/12Z
RUN WAS SLOWER...AND STILL KEPT MUCH OF THE PRECIP AROUND LUCE
COUNTY AND E. THE 18Z GFS WENT BACK TO A SLIGHTLY MORE W IDEA WITH
THE PRECIP. STILL LOOKS LIKE THE COUNTIES ALONG LAKE MI...AND LUCE
COUNTY WILL BE THE MAIN IMPACTS...WITH SOME LAKE ENHANCEMENT OVER N
CENTRAL UPPER MI. IF THE 18Z GFS PANS OUT...MORE SIGNIFICANT CHANGES
BACK TO OUR PREVIOUS FCST/HWO DISCUSSION WILL BE NEEDED. THE 12Z
RUNS HOWEVER WERE MORE CONSISTENT ON KEEPING THE WIDESPREAD PRECIP E.
LOW PRESSURE TRACKING NORTHEASTWARD FROM THE CENTRAL PLAINS THURSDAY
NIGHT THROUGH THE UPPER GREAT LAKES LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL BRING THE POTENTIAL FOR WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO ALL OF UPPER MICHIGAN. THERE IS STILL PLENTY OF
DISCREPANCY...WITH THE 22/12Z ECMWF KEEPING MUCH OF THE PRECIP OVER
THE W THIRD TO HALF OF THE CWA. THE GFS IS A BIT MORE
GENEROUS...WITH A HEALTHY SWATH OF 0.1IN LIQUID. ADDED THE LIGHT TO
MODERATE SNOW POTENTIAL TO THE HWO FOR HOLIDAY TRAVELERS. RAIN MAY
MIX IN OVER LAKE MI FRIDAY AFTERNOON...BEFORE MUCH COOLER AIR PUSHES
IN ACROSS THE ENTIRE AREA FRIDAY NIGHT. 850MB TEMPS W AT 12Z
SATURDAY COULD BE AROUND -16C ON A FAVORABLE NW WIND...EXTENDING
SNOW OVER THE W INTO SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING NORTHEAST TOWARDS THE
AREA. THERE WILL LIKELY BE TWO SURGES OF PRECIPITATION WITH THIS
LOW...THE FIRST COMING DURING THE OVERNIGHT HOURS AND THE SECOND
ARRIVING BY LATE MORNING OR EARLY AFTERNOON. THE SECOND WAVE WILL
PRODUCE THE HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON DEC 22 2014
A LOW PRESSURE SYSTEM OVER THE MISSOURI RIVER VALLEY WILL LIFT
NORTHEAST ON TUESDAY THROUGH EASTERN UPPER MICHIGAN WHILE
WEAKENING. WINDS WILL TURN TO THE EAST-NORTHEAST TONIGHT AND
CONTINUE THROUGH TUESDAY. WHILE MOST LOCATIONS WILL SEE WINDS IN
THE 20-30KT RANGE...THERE MAY BE A FEW GALE FORCE GUSTS TO 35KTS
OVER WESTERN LAKE SUPERIOR. AS THE LOW CONTINUES TO WEAKEN ON
TUESDAY NIGHT...ANOTHER LOW WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY. THIS LOW WILL QUICKLY LIFT NORTHEAST ON
WEDNESDAY...CROSSING LAKE HURON ON WEDNESDAY NIGHT AND MOVING INTO
NORTHERN QUEBEC ON THURSDAY. AT THIS TIME...EXPECT NORTHERLY WINDS
TO STAY BELOW 25KTS OVER LAKE SUPERIOR DURING THAT PERIOD. ANOTHER
LOW WILL TAKE SHAPE IN THE CENTRAL PLAINS ON THURSDAY NIGHT AND
THEN MOVE NORTHEAST THROUGH THE UPPER GREAT LAKES REGION ON FRIDAY
NIGHT. NORTHEAST WINDS UP TO 30 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY BEHIND THIS LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
426 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. MIN
TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO LOWER THAN THE UPR
20S OVER THE INTERIOR W. MAINTAINED MENTION OF FOG THRU THE NGT OVER
THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN ABOVE 32 WITH MOIST AIR
OVER MELTING SN.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 511 PM EST MON DEC 22 2014
HIGHS WILL REMAIN IN THE 30S THROUGH THE DAY FRIDAY...WITH PLENTY OF
GOING ON PRECIP WISE THIS PERIOD. SLUSHY TO WET ROADWAYS WILL GREET
HOLIDAY TRAVELERS THROUGH FRIDAY...UNLESS A QUICK BURST OF SNOW
OCCURS.
INITIALLY HAVE THE EXITING SFC LOW SHIFTING FROM WI AT 00Z
WEDNESDAY...SHIFTING ACROSS LAKE MI OVERNIGHT INTO
WEDNESDAY...BECOMING A PART OF THE NEXT LOW NEARING FROM THE TN
VALLEY WEDNESDAY MORNING. DRIZZLE/FREEZING DRIZZLE WILL LINGER
THROUGH WEDNESDAY OVER THE E THIRD OF THE CWA...BEFORE CHANGING TO
SNOW LATE IN THE DAY.
ALTHOUGH THERE ARE STILL SOME DISCREPANCIES IN EVEN THE WEDNESDAY
NIGHT FCST...I DID TAKE OUT THE MENTION OF THE LOW PUSHING NORTHWARD
OVER E LOWER MI AND LAKE HURON LATE WEDNESDAY INTO WEDNESDAY EVENING
FOR THE EAST HALF OF UPPER MICHIGAN IN THE HWO. THE 22/00Z ECMWF IS
STRONGER/MORE WRAPPED UP...AND AS A RESULT KEEPS WRAP AROUND PRECIP
WEDNESDAY NIGHT INTO THURSDAY OVER OR JUST E OF THE CWA. THE 22/12Z
RUN WAS SLOWER...AND STILL KEPT MUCH OF THE PRECIP AROUND LUCE
COUNTY AND E. THE 18Z GFS WENT BACK TO A SLIGHTLY MORE W IDEA WITH
THE PRECIP. STILL LOOKS LIKE THE COUNTIES ALONG LAKE MI...AND LUCE
COUNTY WILL BE THE MAIN IMPACTS...WITH SOME LAKE ENHANCEMENT OVER N
CENTRAL UPPER MI. IF THE 18Z GFS PANS OUT...MORE SIGNIFICANT CHANGES
BACK TO OUR PREVIOUS FCST/HWO DISCUSSION WILL BE NEEDED. THE 12Z
RUNS HOWEVER WERE MORE CONSISTENT ON KEEPING THE WIDESPREAD PRECIP E.
LOW PRESSURE TRACKING NORTHEASTWARD FROM THE CENTRAL PLAINS THURSDAY
NIGHT THROUGH THE UPPER GREAT LAKES LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL BRING THE POTENTIAL FOR WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO ALL OF UPPER MICHIGAN. THERE IS STILL PLENTY OF
DISCREPANCY...WITH THE 22/12Z ECMWF KEEPING MUCH OF THE PRECIP OVER
THE W THIRD TO HALF OF THE CWA. THE GFS IS A BIT MORE
GENEROUS...WITH A HEALTHY SWATH OF 0.1IN LIQUID. ADDED THE LIGHT TO
MODERATE SNOW POTENTIAL TO THE HWO FOR HOLIDAY TRAVELERS. RAIN MAY
MIX IN OVER LAKE MI FRIDAY AFTERNOON...BEFORE MUCH COOLER AIR PUSHES
IN ACROSS THE ENTIRE AREA FRIDAY NIGHT. 850MB TEMPS W AT 12Z
SATURDAY COULD BE AROUND -16C ON A FAVORABLE NW WIND...EXTENDING
SNOW OVER THE W INTO SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING NORTHEAST TOWARDS THE
AREA. THERE WILL LIKELY BE TWO SURGES OF PRECIPITATION WITH THIS
LOW...THE FIRST COMING DURING THE OVERNIGHT HOURS AND THE SECOND
ARRIVING BY LATE MORNING OR EARLY AFTERNOON. THE SECOND WAVE WILL
PRODUCE THE HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON DEC 22 2014
A LOW PRESSURE SYSTEM OVER THE MISSOURI RIVER VALLEY WILL LIFT
NORTHEAST ON TUESDAY THROUGH EASTERN UPPER MICHIGAN WHILE
WEAKENING. WINDS WILL TURN TO THE EAST-NORTHEAST TONIGHT AND
CONTINUE THROUGH TUESDAY. WHILE MOST LOCATIONS WILL SEE WINDS IN
THE 20-30KT RANGE...THERE MAY BE A FEW GALE FORCE GUSTS TO 35KTS
OVER WESTERN LAKE SUPERIOR. AS THE LOW CONTINUES TO WEAKEN ON
TUESDAY NIGHT...ANOTHER LOW WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY. THIS LOW WILL QUICKLY LIFT NORTHEAST ON
WEDNESDAY...CROSSING LAKE HURON ON WEDNESDAY NIGHT AND MOVING INTO
NORTHERN QUEBEC ON THURSDAY. AT THIS TIME...EXPECT NORTHERLY WINDS
TO STAY BELOW 25KTS OVER LAKE SUPERIOR DURING THAT PERIOD. ANOTHER
LOW WILL TAKE SHAPE IN THE CENTRAL PLAINS ON THURSDAY NIGHT AND
THEN MOVE NORTHEAST THROUGH THE UPPER GREAT LAKES REGION ON FRIDAY
NIGHT. NORTHEAST WINDS UP TO 30 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY BEHIND THIS LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1130 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 810 PM CST MON DEC 22 2014
THE PRECIPITATION OVER MUCH OF NORTHLAND HAS DIMINISHED THIS
EVENING AS FORECAST BY MOST OF THE MODELS. THERE STILL REMAINS
AREAS OF LIGHT SNOW AND DRIZZLE...ESPECIALLY OVER OUR WESTERN
ZONES FROM THE BRAINERD LAKES NORTH TO INTERNATIONAL FALLS. HIGH
RES MODELS SUGGEST THIS WILL DECREASE AS WELL OVERNIGHT. THE
SURFACE LOW OVER WESTERN IOWA IS FORECAST TO LIFT TOWARD THE WI/IL
BORDER BY 12Z TUE. AN AREA OF PRECIP WAS MOVING N/NW TOWARD PRICE
COUNTY AND THAT SHOULD CONTINUE TO MOVE NORTH OVERNIGHT. THE
LATEST HRRR DOES WEAKEN THIS AS WELL OVERNIGHT BEFORE A LARGER
MORE INTENSE AREA OF SNOW MOVES IN TUESDAY MORNING. WE WILL NOT
CHANGE THE ADVISORY TIMING...BUT INSTEAD MENTIONED THE TIMING
ISSUES IN OUR VARIOUS PRODUCTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
MAIN FORECAST CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND
THE POTENTIAL FOR ACCUMULATING SNOW OVER THE EASTERN HALF OF THE
FORECAST AREA TONIGHT THROUGH THE DAY TUESDAY. THE WINTRY MIX OF
DRIZZLE...RAIN AND SNOW THIS AFTERNOON AND EARLY EVENING WILL
CHANGE OVER TO ALL SNOW LATER TONIGHT. PATCHY FOG...LOCALLY
DENSE...WILL ALSO PERSIST THROUGH TUESDAY.
A WINTER WEATHER ADVISORY CONTINUES FOR PORTIONS OF NW WISCONSIN
FROM LATE THIS EVENING THROUGH LATE TUESDAY NIGHT.
LARGE UPPER LOW WILL ROTATE EWD FROM SE/NE THROUGH IA/SRN MN
TONIGHT AND INTO SRN WI/GREAT LAKES AREA ON TUESDAY. ON THE
LEADING NERN EDGE OF THIS SYSTEM A DRY WEDGE OF AIR IS EXPECTED TO
ROTATE INTO THE SYSTEM OVER LAKE SUPERIOR AND NRN MN TONIGHT. THIS
FEATURE WILL ALLOW MUCH OF THE PRECIP ACROSS NE MN TO CHANGE TO DZ
OR FZDZ...WHILE THE SFC LOW FILLS OUT AT THE BOTTOM OF THE
SYNOPTIC TROUGH AND BEGINS TO LIFT TO THE NE...SNOW AND DZ/RA WILL
PUSH IN FROM THE SOUTH.
AS THE LOW MOVES INTO ERN WI AROUND GREEN BAY A WELL DEFINED
DEFORMATION ZONE IS EXPECTED TO FORM ACROSS NRN WI INTO THE U.P.
AND LAKE SUPERIOR. SNOW WILL BECOME ENHANCED IN THIS AREA DURING
THE DAY TUESDAY. THE MOST FAVORABLE TIME FOR HEAVY SNOW WILL BE
FROM TUE MORNING INTO THE AFTERNOON FROM SHELL LAKE TO ASHLAND AND
AREAS TO THE EAST. HIGH SNOWFALL RATES WILL ALLOW A QUICK 2 TO 4
INCHES TO FALL IN A RELATIVELY SHORT PERIOD OF TIME. TOTAL
SNOWFALL AMTS WILL RANGE FROM 3 TO 5 INCHES ACROSS THE ADVISORY
AREA WITH LOCALLY HIGHER SNOWFALL TO 6 INCHES ALONG THE ELEVATED
REGIONS OF THE SOUTH SHORE. AREAS TO THE WEST ALONG THE I-35
AND HIGHWAY 61 CORRIDORS AND INTO THE TWIN PORTS WILL SEE
SNOWFALL AROUND 1 TO 3 INCHES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
FAIRLY ACTIVE WEATHER PATTERN WILL PERSIST INTO THIS WEEKEND.
WIDESPREAD LIGHT SNOW SHOULD BE WINDING DOWN WEDNESDAY NIGHT AT THE
BEGINNING OF THE EXTENDED PERIODS. LAKE EFFECTS WILL PROVIDE SOME
ENHANCEMENT ALONG THE SOUTH SHORE OF LK SUPERIOR..BUT LACK OF TRUE
ARCTIC AIR SHOULD ACT TO LIMIT OVERALL AMOUNTS.
STRONG SURFACE LOW WILL DEVELOP OVER THE TENNESSEE VALLEY REGION
WEDNESDAY AND MOVE TOWARD LAKE HURON BY THURSDAY MORNING..BUT THIS
LOW IS EXPECTED TO REMAIN SUFFICIENTLY FAR EAST WHERE SENSIBLE
WEATHER EFFECTS ON THE DULUTH CWA WILL BE MINIMAL..IF ANY.
A VERY WEAK DISTURBANCE WILL BRUSH BY NORTHERN MINNESOTA WEDNESDAY
NIGHT/THURSDAY..WHICH MAY BRING A BIT OF LIGHT SNOW ACROSS THE VERY
FAR NORTH. OVERALL HOWEVER..THIS IS REALLY NOT EXPECTED TO BE A BIG
DEAL.
THE BIGGEST POTENTIAL WEATHER SYSTEM DURING THE EXTENDED PERIOD
APPEARS TO BE THE RAPIDLY MOVING S/W TROF THAT IS PROGGED TO MOVE
FROM ERN COLORADO TO THE U.P. OF MICHIGAN FROM LATE THURSDAY NIGHT
THROUGH FRIDAY EVENING. THE FAST MOVEMENT WILL ACT TO LIMIT THE
DURATION OF MODERATE TO STRONG FORCING FOR ASCENT..BUT THERE APPEARS
TO BE SOME SUPPORT FOR THE IDEA OF FRONTOGENESIS ENHANCEMENT
DEPICTED IN THE MEDIUM RANGE MODELS. GIVEN THE CHANGES THAT WERE
OBSERVED IN THE MODEL EVOLUTION FOR THE PREVIOUS TWO SIGNIFICANT
SYSTEMS..CONFIDENCE IS SOMEWHAT LESS THAN NORMAL. DETAILS WILL NEED
TO BE RESOLVED AS THE SYSTEM GETS CLOSER DURING THIS WEEK. WITH THAT
SAID..WITH THE AVAILABLE DATA RIGHT NOW..THIS APPEARS TO HAVE
POTENTIAL FOR A HIGH-END ADVISORY OR LOW-END WARNING TYPE EVENT FOR
SOMEWHERE IN..OR CLOSE TO THE DULUTH CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1129 PM CST MON DEC 22 2014
IFR CONDITIONS COVERED THE NORTHLAND LATE THIS EVENING AND WILL
CONTINUE THROUGH MOST OF THE PERIOD. CEILINGS MAY RISE TO LOW END
MVFR AT TIMES TUESDAY AFTERNOON/EVENING.
LOW PRESSURE IN SOUTHWEST IOWA WILL LIFT INTO SOUTHERN WISCONSIN
BY NOON TUESDAY...THEN CONTINUE NORTHEAST. SOME DRIZZLE/LIGHT SNOW
WILL CONTINUE TO BE POSSIBLE OVER NORTHEAST MINNESOTA TONIGHT...BUT
SHOULD DIMINISH IN COVERAGE. SNOW WAS MOVING NORTH THROUGH
NORTHERN WISCONSIN BUT MAY DIMINISH FOR A TIME TONIGHT BEFORE
HEAVIER SNOW MOVES IN TUESDAY MORNING. SOME DRIZZLE/FREEZING
DRIZZLE WILL ALSO BE POSSIBLE AT TIMES.
MORE SIGNIFICANT SNOWFALL WILL DEVELOP OVER MAINLY NORTHERN
WISCONSIN TUESDAY MORNING...THEN DIMINISH LATE TUESDAY AFTERNOON/EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 33 28 31 / 70 60 60 10
INL 32 33 27 31 / 80 30 30 20
BRD 32 33 29 32 / 90 60 50 10
HYR 33 34 30 32 / 80 90 60 20
ASX 33 34 31 32 / 80 100 60 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ002>004-
008-009.
LS...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 AM CST WEDNESDAY FOR
LSZ121-142>148.
&&
$$
UPDATE...MELDE
SHORT TERM...BJT
LONG TERM...MILLER
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
838 PM CST Wed Dec 24 2014
.UPDATE:
Issued at 831 PM CST Wed Dec 24 2014
Already updated the fcst once this evng to account for the
lingering precip across the area and it looks like another update
will be necessary as the pesky lght rain and drizzle will be slow
to exit the area. The precip has slowly been transitioning from
measurable to trace over the past several hrs. So that will be
the flavor thru midnight...lingering patchy drizzle. Temps have
also been slow to fall off and have been holding steady so far
this evng despite the CAA. Still think lows for tonight look good
with upstream obs across wrn MO in the low 30s. All other elements
look reasonable with only minor adjustments to account for short
term trends. A new update will be out shortly.
2%
&&
.SHORT TERM: (Through Tonight)
Issued at 325 PM CST Wed Dec 24 2014
An area of light rain possibly mixed with a few wet snowflakes
currently centered through St. Louis was moving east around 25-30
kts. This precipitation is occurring in association with a trailing
vort max within the cyclonic flow on the backside of the exiting
upper trof. Present indications are it should have exited or just
about exited the eastern CWA counties in south central/southwest IL
at 00z. There might be some lingering patchy drizzle for a few hours
into early evening. Satellite imagery has stratus hanging tough and
still well back into eastern KS and eastern OK at 21z. Trends along
with the RAP and NAM 925 mb RH suggests the clearing trend will be
slow and won`t commence in our CWA until well after midnight, and
the back edge of clouds around 50 miles west of STL at 12z Thursday.
The clouds will help keep temperatures a tad warmer overnight than
the previous forecast.
Glass
.LONG TERM: (Thursday through Next Wednesday)
Issued at 325 PM CST Wed Dec 24 2014
(Thursday through Saturday)
Primary focus thru this period will be precip chances late in the
period.
Mdls remain in good agreement thru Fri. Sfc winds quickly become sly
by tomorrow as ridge quickly moves off to the E. Expect current
cloud deck to move ewd tonight and shud be along/near the MS River
around 12z Thurs. These clouds shud be on the ern boarder of the CWA
by 18z. However, mdls suggest these low clouds will probably be
replaced with CI which shud hinder heating somewhat. Have therefore
kept temps twd the cooler guidance, esp across ern portions of the
CWA will clouds will linger. For Fri, have trended slightly warmer
as strong sly winds will be in place. However, with questions
regarding cloud cover, did not go as high as warmer MOS for now.
Cut off low over srn Rockies begins to open and eject into the
Plains by Fri evening. However, the GEM is a slower soln and
actually redevelops an upper low after the initial s/w is reaching
the nrn Plains. As this soln is an outlier, have trended away from
this soln and twd the other mdls which remain in good agreement.
Have kept PoPs in lower chance category for now as mdl soundings
suggest much of the QPF may be more DZ than RA. Not to mention that
the NAM and local WRF suggest the precip bifurcating with a branch
to the N and one to the S. However, with the trof approaching and
some low level forcing, light RA will be possible. Question becomes
p-types on Sat and Sat night as the cold air filters into the
region. While the GFS soundings suggest precip will end as a brief
period of IP, then SN, setup is typical of this area where precip
will likely end as RA just ahead of the surge of cold air. This is
more likely given the sfc ridge center is currently progd to be over
wrn KS. Regardless, close attention shud be paid to this time period
as mdls come into better agreement.
(Sunday through Wednesday)
Focus quickly turns to temps thru this period.
Will continue trends twd a GFS/ECMWF compromise due to issues with
the GEM mentioned above. The DGEX also becomes a fast outlier as the
next trof ejects into the Plains sometime on Wed.
Relatively cold air moves in place behind the cdfnt on Sat. A
secondary cdfnt is expected to push thru the region Sun night into
Mon ahead of the next system approaching the region late Mon night
into Wed. Have trended temps twd cooler guidance for Tues and beyond
placing temps nearly 20 degrees below seasonal avg.
A number of questions arise with the system on Tues/Wed. The GFS
cuts off an upper low over the swrn U.S. which it is known to do.
The ECMWF ejects this trof into the Plains, but given the weakening
jet upstream of this trof, am not convinced this soln is correct.
With both mdls suggesting very low QPF, will keep only slight chance
PoPs going for now with plenty of time to adjust. The one item both
mdls do agree on is the precip is expected to be all SN.
Tilly
&&
.AVIATION: (For the 00z TAFs through 00z Thursday Evening)
Issued at 542 PM CST Wed Dec 24 2014
Weak surface ridge building in behind system, so light rain,
sprinkles, and flurries to diminish this evening. Otherwise, MVFR
cigs to persist through the night. Low level RH in models begins
to dry out towards daybreak, so will see cigs lift and scatter out
by 09z Thursday at KCOU, 12z Thursday at KUIN and by 13z-14z
Thursday in metro area. As for winds, northwest winds to back to
the west late this evening, then back to the south by daybreak and
remain that way for rest of forecast period.
Specifics for KSTL:
Weak surface ridge building in behind system, so light rain,
sprinkles, and flurries to diminish this evening. Otherwise, MVFR
cigs to persist through the night. Low level RH in models begins
to dry out towards daybreak, so will see cigs lift and scatter out
by 13z-14z Thursday in metro area. As for winds, northwest winds
to back to the west by 06z Thursday, then back to the south by
14z Thursday and remain that way for rest of forecast period.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
543 PM CST Wed Dec 24 2014
.SHORT TERM: (Through Tonight)
Issued at 325 PM CST Wed Dec 24 2014
An area of light rain possibly mixed with a few wet snowflakes
currently centered through St. Louis was moving east around 25-30
kts. This precipitation is occurring in association with a trailing
vort max within the cyclonic flow on the backside of the exiting
upper trof. Present indications are it should have exited or just
about exited the eastern CWA counties in south central/southwest IL
at 00z. There might be some lingering patchy drizzle for a few hours
into early evening. Satellite imagery has stratus hanging tough and
still well back into eastern KS and eastern OK at 21z. Trends along
with the RAP and NAM 925 mb RH suggests the clearing trend will be
slow and won`t commence in our CWA until well after midnight, and
the back edge of clouds around 50 miles west of STL at 12z Thursday.
The clouds will help keep temperatures a tad warmer overnight than
the previous forecast.
Glass
.LONG TERM: (Thursday through Next Wednesday)
Issued at 325 PM CST Wed Dec 24 2014
(Thursday through Saturday)
Primary focus thru this period will be precip chances late in the
period.
Mdls remain in good agreement thru Fri. Sfc winds quickly become sly
by tomorrow as ridge quickly moves off to the E. Expect current
cloud deck to move ewd tonight and shud be along/near the MS River
around 12z Thurs. These clouds shud be on the ern boarder of the CWA
by 18z. However, mdls suggest these low clouds will probably be
replaced with CI which shud hinder heating somewhat. Have therefore
kept temps twd the cooler guidance, esp across ern portions of the
CWA will clouds will linger. For Fri, have trended slightly warmer
as strong sly winds will be in place. However, with questions
regarding cloud cover, did not go as high as warmer MOS for now.
Cut off low over srn Rockies begins to open and eject into the
Plains by Fri evening. However, the GEM is a slower soln and
actually redevelops an upper low after the initial s/w is reaching
the nrn Plains. As this soln is an outlier, have trended away from
this soln and twd the other mdls which remain in good agreement.
Have kept PoPs in lower chance category for now as mdl soundings
suggest much of the QPF may be more DZ than RA. Not to mention that
the NAM and local WRF suggest the precip bifurcating with a branch
to the N and one to the S. However, with the trof approaching and
some low level forcing, light RA will be possible. Question becomes
p-types on Sat and Sat night as the cold air filters into the
region. While the GFS soundings suggest precip will end as a brief
period of IP, then SN, setup is typical of this area where precip
will likely end as RA just ahead of the surge of cold air. This is
more likely given the sfc ridge center is currently progd to be over
wrn KS. Regardless, close attention shud be paid to this time period
as mdls come into better agreement.
(Sunday through Wednesday)
Focus quickly turns to temps thru this period.
Will continue trends twd a GFS/ECMWF compromise due to issues with
the GEM mentioned above. The DGEX also becomes a fast outlier as the
next trof ejects into the Plains sometime on Wed.
Relatively cold air moves in place behind the cdfnt on Sat. A
secondary cdfnt is expected to push thru the region Sun night into
Mon ahead of the next system approaching the region late Mon night
into Wed. Have trended temps twd cooler guidance for Tues and beyond
placing temps nearly 20 degrees below seasonal avg.
A number of questions arise with the system on Tues/Wed. The GFS
cuts off an upper low over the swrn U.S. which it is known to do.
The ECMWF ejects this trof into the Plains, but given the weakening
jet upstream of this trof, am not convinced this soln is correct.
With both mdls suggesting very low QPF, will keep only slight chance
PoPs going for now with plenty of time to adjust. The one item both
mdls do agree on is the precip is expected to be all SN.
Tilly
&&
.AVIATION: (For the 00z TAFs through 00z Thursday Evening)
Issued at 542 PM CST Wed Dec 24 2014
Weak surface ridge building in behind system, so light rain,
sprinkles, and flurries to diminish this evening. Otherwise, MVFR
cigs to persist through the night. Low level RH in models begins
to dry out towards daybreak, so will see cigs lift and scatter out
by 09z Thursday at KCOU, 12z Thursday at KUIN and by 13z-14z
Thursday in metro area. As for winds, northwest winds to back to
the west late this evening, then back to the south by daybreak and
remain that way for rest of forecast period.
Specifics for KSTL:
Weak surface ridge building in behind system, so light rain,
sprinkles, and flurries to diminish this evening. Otherwise, MVFR
cigs to persist through the night. Low level RH in models begins
to dry out towards daybreak, so will see cigs lift and scatter out
by 13z-14z Thursday in metro area. As for winds, northwest winds
to back to the west by 06z Thursday, then back to the south by
14z Thursday and remain that way for rest of forecast period.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
901 AM MST TUE DEC 23 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SKIES HAVE CLEARED A BIT MORE THAN WHAT IS FORECASTED. MODELS ARE
NOT HAVING A GOOD HANDLE ON THIS VERY WELL...SO HAD TO USE THE
CONCEPTUAL MODEL. TWEAKED WINDS TO LATEST MODEL DATA. REST OF
FORECAST LOOKED GOOD. TFJ
PREVIOUS DISCUSSION...
THE SYNOPTIC PATTERN BEGINS WITH A LARGE TROUGH OF COLD AIR OVER
CENTRAL CONUS AND AN EQUALLY LONG-WAVE RIDGE OVER THE WEST. THIS
PLACES NORTHWEST FLOW ALOFT OVER NORTHEAST MONTANA. THERE ARE
STILL LINGERING EFFECTS FROM THE DEPARTING WINTER STORM...MAINLY
LIGHT RADAR ECHOES NEAR THE YELLOWSTONE RIVER VALLEY AREA. WITH
ONLY LIGHT ECHOES THE WINTER WEATHER ADVISORY WAS CANCELLED EARLY
THIS MORNING. THE APPROACHING RIDGE IS PUSHING WARM/COLD
BOUNDARY EAST AS A WARM FRONT THAT WILL OVERRUN THE LOCAL REGION
TONIGHT AND WEDNESDAY.
TODAY...WILL NOT SEE MUCH TEMPERATURES DIFFERENCE FROM
MONDAY...BUT WIND WILL BE LIGHT...ELIMINATING THE WIND CHILL
EFFECT. ALSO EXPECT CLEARING FROM THE WEST.
TONIGHT...THE WARM FRONT WILL INCREASE 850 MB TEMPERATURES WHICH
WILL RISE TO AROUND +2C TO +4C...AS A SURFACE TROUGH ALSO SLIDES
DOWN FROM CANADA. SOME PACIFIC MOISTURE RIDING THE TOP OF THE
FLATTENING RIDGE WILL MAKE IT INTO THE REGION FOR POSSIBLE LIGHT
FREEZING RAIN.
WEDNESDAY...AN UPPER DISTURBANCE MOVING ACROSS THE PRAIRIE
PROVINCES WILL SEND THE COLD BOUNDARY SOUTH AND ACT AS A COLD
FRONT. MODELS ARE SHOWING ANOTHER TROUGH SLAMMING INTO THE WEST
COAST. THIS WILL SEND MORE MOISTURE OVER THE DIVIDE...REACHING
PORTIONS OF NEMONT WITH MIXED PRECIPITATION. THE FREEZING RAIN
POTENTIAL SUGGESTS THAT SOME TRAVEL MAY BE IMPACTED BY ICE THROUGH
WEDNESDAY MORNING BEFORE TEMPERATURES RISE ABOVE FREEZING.
WEDNESDAY NIGHT AND THURSDAY...AS THE FRONT MOVES SOUTH SO DOES
THE PRECIPITATION. A BLEND OF THE MODELS ARE SHOWING BASICALLY THE
SOUTHWEST HALF OF THE CWA GETTING THE MOST QPF. TEMPERATURE
PROFILES SUGGEST ALL SNOW. THIS IS THE CHRISTMAS STORM THAT HAS
BEEN ADVERTISED FOR THE REGION. THE BRUNT OF IT FOR US WILL HAPPEN
THROUGH THURSDAY MORNING THEN RAPIDLY TAPER OFF FROM THE NORTH BY
AFTERNOON. BASED ON QPF AND SNOW RATIO THE TOTAL SNOW COULD RANGE
FROM AROUND 3.5 INCHES IN THE SOUTHWEST ZONES TO LESS THAN A
HALF INCH IN THE NORTHEAST ZONES. WITH MODELS COMING TOGETHER MORE
THE UNCERTAINTY IS DIMINISHING FOR A SNOW EVENT WEDNESDAY NIGHT
AND THURSDAY SPREAD OVER MOST OF CENTRAL AND EASTERN MONTANA.
SCT
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
UPPER RIDGE BUILDING ALONG THE WEST COAST WILL OPEN THE REGION TO
THE ARCTIC...RESULTING IN MUCH COLDER TEMPERATURES BETWEEN
CHRISTMAS AND NEW YEARS.
MIDWEEK GREAT BASIN STORM SYSTEM SHOULD BE WINDING DOWN ACROSS
NORTHERN MONTANA BY THURSDAY EVENING WITH CANADIAN HIGH PRESSURE
PUSHING INTO THE NORTHERN PLAINS. A SECONDARY SHORTWAVE DROPPING
ACROSS ALBERTA INTO THE LONGWAVE TROF COULD BRING A FEW FLURRIES
OR SNOW SHOWERS ON FRIDAY.
NEXT SHORTWAVE SLIDES DOWN THE CANADIAN ROCKIES FOR THE WEEKEND.
SLIGHT WARM FRONT/CHINOOK BOUNDARY DEVELOPS IN CENTRAL MONTANA ON
SATURDAY WITH WAVE SLIDING SOUTH ALONG THE BOUNDARY SATURDAY
NIGHT. ANOTHER SURGE OF COLD AIR FOLLOWS ALONG WITH PACIFIC
MOISTURE STREAMING EAST OF THE DIVIDE...SETTING THE STAGE FOR
UPSLOPE AND COLD AIR ADVECTION SNOW ON SUNDAY. BEST CHANCE WILL BE
THE SOUTHWEST WITH THE ADDITION OF TERRAIN INFLUENCES.
COLDEST AIR COMES OVER THE REGION ON MONDAY WITH THE UPPER TROF
AXIS. CANADIAN HIGH FOLLOWS WITH DRIER AIRMASS MONDAY NIGHT FOR A
GOOD POSSIBILITY OF TEMPERATURES DROPPING BELOW ZERO ACROSS MOST
OF THE CWA BY TUESDAY MORNING. EBERT
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR... ISOLATED MVFR POSSIBLE.
SYNOPSIS: A LOW PRESSURE SYSTEM CONTINUES TO EXIT THE REGION VIA
SOUTH DAKOTA WITH SOME LINGERING AVIATION ISSUES EARLY THIS
MORNING AT KOLF AND KSDY. LOW CLOUD DECK WILL GRADUALLY MOVE EAST
AND EXIT THE REMAINING TAFS.
FOG: AN ISOLATED CHANCE FOR FOG AT KOLF EXISTS TONIGHT IN BOTH
THE RAP AND NAMDNG5 MODELS. HOWEVER... WITH MID TO HIGH CLOUDS MOVING INTO
THE AREA AT PEAK FOG HOURS.... CONFIDENCE IS TOO LOW TO INCLUDE IN
THE TAF AT THIS TIME.
WINDS: OUT OF THE WEST FROM 5 TO 15 KTS THROUGH THIS AFTERNOON...
BACKING TO THE SOUTH AND SOUTHWEST AND DECREASING TO 5 TO 10 KTS
OVERNIGHT.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
300 PM CST TUE DEC 23 2014
.SHORT TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
BAND OF GENERALLY LIGHT MIXED PRECIP CONTINUES TO TRACK SLOWLY
SOUTH ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA AT 20Z. THIS
TREND IS EXPECTED TO CONTINUE INTO THE EVENING AS UPPER TROUGH
MOVES SLOWLY EAST. TEMPERATURES ARE IN THE MID TO UPPER 30S SO
WHATEVER SNOW DOES FALL MELTS FAIRLY QUICKLY. NDOR WEB CAMS SHOW
LITTLE TO NO SNOW COVER SOUTH OF A COLUMBUS TO TEKAMAH LINE.
LATEST RAP MODEL INDICATES A DIMINISHING TREND TO THE PRECIP THIS
EVENING WITH ONLY MINOR ACCUMULATIONS EXPECTED AS TEMPERATURES
FALL TO NEAR 32 THROUGH 06Z. STRONGER DYNAMICS SHIFT WELL EAST OF
THE AREA TONIGHT TO THE TENNESSEE AND LOWER OHIO VALLEY WITH
SHORT WAVE RIDGING BUILDING INTO THE NORTHERN PLAINS.
FORECAST SOUNDINGS SUGGEST DECREASING CLOUDS ACROSS THE AREA FOR
WEDNESDAY ALTHOUGH EASTERN AREAS MAY BE LIMITED TO LATE AFTERNOON
FOR ANY POTENTIAL VIEWING OF SUNSHINE. CLEARING TREND CONTINUES
WEDNESDAY NIGHT INTO THURSDAY BEFORE CLOUDS INCREASE ONCE AGAIN
THURSDAY NIGHT AND FRIDAY BEHIND THE NEXT COLD FRONT AND
APPROACHING UPPER TROUGH. SOME LIGHT SNOW IS LIKELY AGAIN WITH
THIS SYSTEM ON FRIDAY BUT NO MAJOR IMPACT ON TRAVEL IS EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
SNOW MAY LINGER INTO FRIDAY NIGHT FOR SOUTHERN PARTS OF THE AREA
THEN DRY BUT COLD FOR THE WEEKEND. STRONG TROUGHING DEVELOPS OVER
THE CENTRAL PART OF THE NATION EARLY NEXT WEEK WITH MUCH COLDER
AIR ON TAP FOR THE END OF THE YEAR.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1120 AM CST TUE DEC 23 2014
IFR CEILINGS WILL LIKELY PREVAIL THROUGH MOST OF THE PERIOD. BAND
OF PCPN...MIXED RAIN AND SNOW...WILL CONTINUE TO DROP SOUTHEAST
ACROSS KLNK AND KOMA. THIS WILL LIKELY TURN TO MAINLY SNOW LATER
THIS AFTN AND CONTINUE INTO EARLY EVENING BEFORE ENDING. VSBYS MAY
DROP TO AROUND 1 MILE IN THE PREVAILING SNOW. FOR KOFK...LOOK FOR
SCT AREAS OF LIGHT SNOW OR SNOW SHOWERS THE REST OF THE DAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS ELKO NV
454 PM PST WED DEC 24 2014
.SYNOPSIS...ON THE LATEST SATELLITE IMAGE THERE IS A SHIELD OF
CLOUDS FROM UTAH TO THE PACIFIC OCEAN. THIS LOW PRESSURE SYSTEM WILL
DELIVER A BATCH OF WINTRY WEATHER THIS EVENING....OVER NIGHT AND
TOMORROW. THE BULK OF THE SNOW IS ANTICIPATED OVER NIGHT. IN
ADDITION TO SNOW...EXPECTING GUSTY WINDS...BLOWING SNOW AND BRUTALLY
COLD TEMPERATURES.
&&
.UPDATE...DECIDED TO UPDATE THE FORECAST DUE TO RADAR TRENDS AND
MESONET OBSERVATIONS. PLACES IN HUMBOLDT COUNTY HAVE ALREADY SEEN
GUSTS BETWEEN 45 AND 65 MPH. KMWC GUSTED TO 59 MPH AND CHANGED
OVER TO SNOW. RAISED WIND GUSTS GRIDS...SO POINT/CLICK WOULD READ
HIGHER GUSTS RIGHT ALONG THE FRONT. THESE WINDS WILL IMPACT THE
REST OF EASTERN NEVADA THROUGH THE EVENING. SOME LIGHTNING MAY BE
POSSIBLE RIGHT ALONG THE FRONT...BUT NOT CONFIDENT ENOUGH TO PUT
IN WXGRIDS. LOCALIZED BLIZZ CONDITIONS WILL ALSO BE POSSIBLE RIGHT
NEAR THE FRONT. TRAVEL IS NOT RECOMMENDED AS THE FRONT PASSES.
&&
.PREV DISCUSSION... /ISSUED AT 215 PM /
SYNOPSIS...ON THE LATEST SATELLITE IMAGE THERE IS A SHIELD OF
CLOUDS FROM UTAH TO THE PACIFIC OCEAN. THIS LOW PRESSURE SYSTEM WILL
DELIVER A BATCH OF WINTRY WEATHER THIS EVENING....OVER NIGHT AND
TOMORROW. THE BULK OF THE SNOW IS ANTICIPATED OVER NIGHT. IN
ADDITION TO SNOW...EXPECTING GUSTY WINDS...BLOWING SNOW AND BRUTALLY
COLD TEMPERATURES.
SHORT TERM...TONIGHT THROUGH SATURDAY. AS ADVERTISED...EXPECTING A
SIGNIFICANT WINTER WEATHER STORM THIS EVENING...OVER NIGHT AND INTO
TOMORROW. THE NAM...THE GFS AND THE RAP ARE PRETTY CONSISTENT
BRINGING THE QPF INTO THE LKN CWA AFTER 4 PM TODAY. THE GFS ENSEMBLE
MEMBERS ARE TIGHTLY CLUSTERED WITH THE PLACEMENT OF THE SURFACE LOW
OVER NE NV...WHEREAS THE ECMWF INDIVIDUAL MEMBERS ARE ROUGHLY 50 TO
100 MILES SOUTH OF THE GFS MEAN. LITTLE SUBTLE DIFFERENCES LIKE THIS
WILL MAKE THE DIFFERENCE IN FINAL SNOW TOTAL ACCUMULATIONS. THE NCEP
RMOP IS WELL INTO BLUE TERRITORY EVEN AT 24 HRS. BUT THE DYNAMICS
ARE IN PLACE FOR A SNOW AND WIND EVENT. KEPT HEADLINES IN
PLACE...BUT ADDED AN NPW FOR NORTHERN NYE. IN THE WAKE OF THE
FRONTAL PASSAGE...EXPECTING CAA AND ROBUST NORTHERLY FLOW.
LONG TERM...SATURDAY NIGHT THROUGH NEXT WEDNESDAY. EC AND GFS IN
FAIRLY GOOD AGREEMENT WITH THE OVERALL PATTERN. EXPECT VERY COLD
AND LARGELY DRY WEATHER ACROSS NEVADA THIS WEEKEND AND INTO NEXT
WEEK. COLD FRONT DROPPING SOUTH FROM CANADA WILL IS EXPECTED TO BE
JUST NORTH OF THE IDAHO-NEVADA BORDER SATURDAY NIGHT. THE VERY COLD
PART OF THE AIRMASS ASSOCIATED WITH AN ARCTIC AIRMASS BEGINS TO MOVE
INTO CWA DURING THE DAY SUNDAY. SINCE THE AIRMASS IS COLD AND WITH
SOME LOW LEVEL MOISTURE AVAILABLE...EXPECT JUST MAINLY LIGHT SNOW
WITH HEAVIEST AMOUNTS IN THE UPSLOPE FAVORABLE AREAS THROUGH MONDAY.
THE COLD AIRMASS IS REINFORCED AND CONTINUES TO PUSH SOUTH OVER THE
CWA AS THE 700 MB TEMPERATURES DROP NEAR -20C BY MONDAY AFTERNOON.
WITH SNOW COVER...DAYTIME TEMPERATURES MONDAY IS EXPECTED TO BE ONLY
IN THE LOW 20S AND TUESDAY WILL BE LUCKY TO MAKE IT TO THE 20 DEGREE
MARK. HAVE DROP LOW TEMPERATURES 5 TO 15 DEGREES NEXT TUESDAY AND
WEDNESDAY WITH LOWS SHOULD BE -15 BELOW ZERO TO NEAR ZERO MOST
LOCATIONS TUESDAY AND WEDNESDAY MORNINGS. JH
AVIATION...CIGS WILL LOWER THIS EVENING WITH COLD FRONT EXPECTED TO
PUSH INTO WMC AROUND 01-02Z...EKO 03-04Z AND AROUND ELY 05-06Z.
AHEAD OF THE COLD FRONT...S/SW WINDS OF 15 TO 25KTS WITH G40KTS AT
ALL TAF SITES...FOLLOWED BY SEVERAL HOURS OF IFR/LIFR IN SN/BLSN AT
KWMC...KEKO AND KELY BEHIND THE FRONT. AFTER THE FRONTAL PASSAGE
AROUND 05Z...STRONG GUSTY NE WINDS OF 35 TO 45 KNOTS AT TPH WILL
DEVELOP. THESE GUSTY WINDS WILL CONTINUE THROUGH AT LEAST THURSDAY
AFTERNOON.
ADDITIONALLY...THIS EVENING AND OVER NIGHT...EXPECTING SNOW TO
ACCUMULATE ON THE RUNWAYS OF KEKO. THIS IS A HIGH CONFIDENCE
EVENT...AND SNOW IS VISIBLE OVER NE NV ON THE LATEST RADAR IMAGE.
ADDITIONAL IMPACTS TO THE AVIATION CUSTOMERS WILL
INCLUDE...OBSCURED MT TOPS...LIGHT TO OCNL MODERATE TURBULENCE
AND LIGHT TO MODERATE ICING. THIS STORM WILL ALSO IMPACT SLC ON
THURSDAY/FRIDAY...POSSIBLY IMPACTING COMMERCIAL TRAFFIC BETWEEN
EKO AND SLC.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR NORTHERN
ELKO COUNTY-SOUTH CENTRAL ELKO COUNTY-SOUTHWEST ELKO COUNTY-
WHITE PINE COUNTY.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THURSDAY FOR HUMBOLDT
COUNTY-NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY-
SOUTHERN LANDER COUNTY AND SOUTHERN EUREKA COUNTY.
WIND ADVISORY FROM 1 AM TO 4 PM PST THURSDAY FOR SOUTHEASTERN
ELKO COUNTY.
WINTER STORM WARNING UNTIL 4 PM PST THURSDAY FOR RUBY MOUNTAINS
AND EAST HUMBOLDT RANGE.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THURSDAY FOR
NORTHEASTERN NYE COUNTY-NORTHWESTERN NYE COUNTY.
WIND ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST THURSDAY FOR
NORTHEASTERN NYE COUNTY-NORTHWESTERN NYE COUNTY.
&&
$$
94/99
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
756 PM EST WED DEC 24 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
800 PM EST UPDATE..
UPDATED WIND ADVISORY... WIND ADVISORY NOW IN EFFECT STARTING 1 AM
EST...
RAIN SHOWERS HAVE PRETTY MUCH EXITED THE REGION TO THE EAST AND WE
SHOULD REMAIN IN A LULL FOR THE NEXT FEW HOURS. A COLD FRONT WILL
SURGE ACROSS THE REGION AFTER MIDNIGHT TONIGHT BRINGING AN
ADDITIONAL SHOT OF RAIN SHOWERS. A FEW RUMBLES OF THUNDER WILL BE
POSSIBLE AS THE FROPA MOVES EAST. WE ARE STILL EXPECTING STRONG
WINDS WITH THIS FRONT AND IS MOVING SLIGHTLY MORE QUICKLY THAN
EXPECTED.
COLD FRONT IS ADVANCING QUICKLY TO THE EAST AND IS JUST
CROSSING INTO WESTERN PENNSYLVANIA. EXPECT THIS FRONT TO START TO
IMPACT THE CWA AROUND 06Z IN THE FAR WESTERN EDGES... THUS CHANGED
THE START TIME OF THE WIND ADVISORY FROM 5 TO 1AM. HIGH WINDS WILL
QUICKLY SPREAD EAST DURING THE EARLY MORNING HOURS ON THURS.
LOOKING AT FORECAST SOUNDINGS AND CURRENT OBSERVATIONS... BELIEVE
GUSTS SHOULD REMAIN BELOW 45 KNOTS ACROSS THE CWA WHEN THE FRONT
PASSES THROUGH... DECIDED TO NOT UPGRADE TO A WARNING. WINDS ARE
EXPECTED TO REMAIN STRONG THROUGH MUCH OF DAY TOMORROW. FOR MORE
INFORMATION PLEASE READ PREVIOUS DISCUSSION BELOW.
PREVIOUS FORECAST...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB
WIND FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR
AREA. ONCE THIS LIFTS NE OF THE REGION LATER THIS
AFTERNOON...THERE WILL BE A LULL IN THE PRECIP UNTIL THE COLD
FRONT WHICH WAS PRESENTLY EXTENDED FROM SERN LWR MI TO FAR WRN OH
TO CNTRL KY RACES EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE
THAT WILL PASS THRU THE REGION LATER TONIGHT. THIS FEATURE WILL BE
THE IMPETUS TO FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY
AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRFNMM AND WRFARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECWMF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FOERCAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON-DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
00Z UPDATE...
STRONG COLD FRONTAL PASSAGE 05Z-08Z WITH SHOWERS AND WIND SHIFT
TO WSW INCLUDING GUSTS 30-35 KTS...EVENTUALLY WESTERLY BY LATER IN
THE MORNING. ISOLATED CB CONTAINED WITHIN SHOWER LINE...BUT NOT
ENOUGH COVERAGE NOR CONFIDENCE TO INCLUDE IN TAFS AT THIS TIME.
BEFORE THE FRONTAL PASSAGE...LOW LEVEL WIND SHEAR FROM
SSW FLOW 1500-2000 FT AGL NOW STRENGTHENING TO 45 KTS...VERSUS
RELATIVELY LIGHT SE TO S AT SURFACE UNDERNEATH THE INVERSION.
MOISTURE TRAPPED UNDER THAT INVERSION TOO...YIELDING LIFR CIGS AND
LOW VIS AT KBGM /NEAR AIRPORT MINS/...AND AT OR ON THE WAY TO FUEL
ALT REQ MVFR CIG FOR MOST OTHER TERMINALS. KSYR IS THE
EXCEPTION...VFR DUE TO DOWNSLOPING. KITH CIG TO WAVER BETWEEN IFR
AND MVFR. SOON AFTER FRONTAL PASSAGE...CIGS TO ACTUALLY LIFT /EVEN
SCT OUT FOR A TIME FOR SOME/ AS INVERSION DISAPPEARS AND DRIER AIR
STARTS WORKING IN...BUT GUSTY POST-FRONTAL WINDS WILL OCCUR
THROUGH MOST OF THE COMING DAY AND A HIGHER END MVFR CIG.
HOWEVER...WITH THAT LOSS OF INVERSION AND MIXING DOWN OF
WINDS...LLWS ALSO WILL GO AWAY WITH THE FRONTAL PASSAGE.
OUTLOOK...
THU NGT...LINGERING MVFR CIG KSYR-KRME.
FRI/SAT...VFR.
SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR NYZ009-
015>018-022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/KAH
SHORT TERM...DJN
LONG TERM...JAB/MSE/TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
708 PM EST WED DEC 24 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB WIND
FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO THE
RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR AREA.
ONCE THIS LIFTS NE OF THE REGION LATER THIS AFTERNOON...THERE WILL BE A
LULL IN THE PRECIP UNTIL THE COLD FRONT WHICH WAS PRESENTLY
EXTENDED FROM SERN LWR MI TO FAR WRN OH TO CNTRL KY RACES
EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE THAT WILL PASS THRU
THE REGION LATER TONIGHT. THIS FEATURE WILL BE THE IMPETUS TO
FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRFNMM AND WRFARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECWMF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FOERCAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON-DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
00Z UPDATE...
STRONG COLD FRONTAL PASSAGE 05Z-08Z WITH SHOWERS AND WIND SHIFT
TO WSW INCLUDING GUSTS 30-35 KTS...EVENTUALLY WESTERLY BY LATER IN
THE MORNING. ISOLATED CB CONTAINED WITHIN SHOWER LINE...BUT NOT
ENOUGH COVERAGE NOR CONFIDENCE TO INCLUDE IN TAFS AT THIS TIME.
BEFORE THE FRONTAL PASSAGE...LOW LEVEL WIND SHEAR FROM
SSW FLOW 1500-2000 FT AGL NOW STRENGTHENING TO 45 KTS...VERSUS
RELATIVELY LIGHT SE TO S AT SURFACE UNDERNEATH THE INVERSION.
MOISTURE TRAPPED UNDER THAT INVERSION TOO...YIELDING LIFR CIGS AND
LOW VIS AT KBGM /NEAR AIRPORT MINS/...AND AT OR ON THE WAY TO FUEL
ALT REQ MVFR CIG FOR MOST OTHER TERMINALS. KSYR IS THE
EXCEPTION...VFR DUE TO DOWNSLOPING. KITH CIG TO WAVER BETWEEN IFR
AND MVFR. SOON AFTER FRONTAL PASSAGE...CIGS TO ACTUALLY LIFT /EVEN
SCT OUT FOR A TIME FOR SOME/ AS INVERSION DISAPPEARS AND DRIER AIR
STARTS WORKING IN...BUT GUSTY POST-FRONTAL WINDS WILL OCCUR
THROUGH MOST OF THE COMING DAY AND A HIGHER END MVFR CIG.
HOWEVER...WITH THAT LOSS OF INVERSION AND MIXING DOWN OF
WINDS...LLWS ALSO WILL GO AWAY WITH THE FRONTAL PASSAGE.
OUTLOOK...
THU NGT...LINGERING MVFR CIG KSYR-KRME.
FRI/SAT...VFR.
SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY FROM 5 AM TO 7 PM EST THURSDAY FOR NYZ009-
015>018-022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB/MSE/TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
242 PM EST TUE DEC 23 2014
.SYNOPSIS...
A LARGE STORM SYSTEM WILL TRACK NORTHEAST FROM THE SOUTH CENTRAL
PLAINS TO THE EASTERN GREAT LAKES TONIGHT AND WEDNESDAY AND THEN
INTO CANADA BY CHRISTMAS DAY. THIS STORM WILL BRING A WIDESPREAD
RAIN TO OUR REGION BEGINNING LATER TONIGHT AND LASTING INTO
WEDNESDAY NIGHT. THE STORM WILL ALSO SWING A COLD FRONT THROUGH
THE REGION EARLY CHRISTMAS MORNING WITH RAIN SHOWERS AND EVEN A
FEW THUNDERSTORMS WITH GUSTY WINDS. AFTER THE FRONT PASSES BY CHRISTMAS
MORNING...IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR AND MILD WEATHER TO OUR REGION ON
FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
FOR WEDNESDAY NIGHT...MAIN CONCERN IS THE POTENTIAL FOR A QLCS OR
NARROW COLD FRONTAL RAIN BAND ALONG THE COLD FRONT WHICH SWINGS
THRU THE REGION BY 4-8Z THU. TIMING OF THIS FRONT IS STILL UNCERTAIN
BUT IT APPEARS IT WILL COME THRU JUST AFTER MIDNIGHT OR SO. THE
DYNAMICS ARE VERY IMPRESSIVE AS ALL SYNOPTIC MODELS SHOW A STRG
UPPER LEVEL PV MAX SWINGING THRU WITH SRG DVRG ALOFT ERLY THU AM.
THE LOW TO MID LEVEL WINDS AT FROPA WERE VERY STRG WITH 0-1 KM
BULK SHEAR AT 45 KNOTS, 0-3 KM ARND 50-60 KNOTS AND 0-6 KM FROM 80
TO 100 KNOTS DEPENDING ON THE MODEL. 0-1 KM HELICITIES WERE
PROGGED CLOSE TO 300 M2/S2. CAPES WERE MARGINAL WHICH IS TO BE
EXPECTED... RUNNING POTENTIALLY UP TO 250 J/KG OR SO MAINLY IN OUR
ERN ZONES. DEWPOINTS ARE PROJECTED TO CLIMB ABV 50F IN THE SRLY
FLOW...ESPECIALLY ACRS NE PA TO EC NY. MODELS SHOW THAT THE DWPTS
AT 850 MB CLIMB ABV 10C WHICH IS 50F AS WELL ACRS ENTIRE AREA. WE
RAN OUR LOCAL SVR WX ANALOG CHECKLIST WHICH COMPARES FORECAST
PARAMETERS WITH HISTORICAL EVENTS AND IT RETURNED 4 OUT OF 5
EVENTS THAT HAD SIGNIFICANT WIND DAMAGE. 3 OF THE 5 EVENTS HAD
ISOLATED TORNADOES INCLUDING THE F2 OF DEC 2006 WHICH HIT NE PA.
FOR NOW HAVE MENTION OF THUNDERSTORMS WITH GUSTY WINDS IN GRIDS
WED NGT/ERLY THU. WILL HIGHLIGHT POTENTIAL FOR STRONG TO LOCALLY
SEVERE THUNDERSTORMS IN THE HWO AS SPC HAS SOME OF OUR AREA IN A
MARGINAL RISK.
AFTER FROPA ON CHRISTMAS DAY...IT WILL BE WINDY WITH PRESSURE
RISES OF ABT 10 TO 15 MB / 12 HOURS IN C NY WHICH IS CLOSE TO
ADVY CRITERIA. WILL MENTION POTENTIAL FOR WIND GUSTS TO 50 MPH IN
HWO FOR C NY...MAINLY FINGER LAKES REGION TO SYR/RME AREAS. THERE
WILL ALSO BE SCT RAIN AND SNOW SHOWERS ARND IN THE BACKLASH OF
THIS LARGE CYCLONE WHICH TAPERS OFF THU NGT.
FRIDAY WILL BE FAIR AND STILL MILD AS A RDG OF HIGH PRESSUIE
BUILDS ACRS THE REGION AS HGHTS RAPIDLY RISE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
213 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
137 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB/TAC
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1256 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADARS SHOW A BAND OF RAIN LIFTING NORTHEAST INTO CENTRAL NY AND
NRN PA IN ASSCTN WITH A SHORT WAVE THAT WAS RIPPLING NORTHEASTWARD
INTO THE NE U.S. THIS FEATURE WAS SEEN AS SOME ENHANCED CLOUD TOPS
ON THE IR IMAGERY AT THIS TIME. THIS FEATURE WILL RACE OFF TO THE
NORTHEAST BY EARLY AFTERNOON AND THE RAIN WILL GO WITH IT LEAVING
BEHIND PATCHY AREAS OF LIGHT RAIN AND DRIZZLE FOR THE REST OF THE
AFTERNOON AND MUCH OF TONIGHT. A FEW PATCHES OF STEADIER RAIN CUD
ADVECT THRU THE REGION AS PER HRRR LATE AFTERNOON/EVENING. SO WILL KEEP
CHC POPS GOING FOR AFTERNOON AND MUCH OF TONIGHT TO COVER ANY
POCKETS OF LIGHT RAIN/DRIZZLE OR A BRIEF STEADIER PD OF RAIN. MAIN
SHIELD OF RAIN ARRIVES BTWN 8 AND 12Z WED AS ONE OF THE FIRST
SIGNIFICANT MAIN WAVES RIDES NORTHEASTWARD AHEAD OF THE DIGGING
TROUGH THAT DROPS INTO THE SRN U.S LATER TONIGHT. THIS WAVE WILL
ACCELERATE A SRLY LLJ WHICH ADVECTS PLENTY OF MOISTURE NORTHWARD
INTO NY AND PA AS IT GLIDES UP THE ISENTROPES LATE TONIGHT. IN
ADDTN...UPR DVRG INCREASES AS WELL. THIS IS RECIPE FOR A
WIDESPREAD AREA OF RAIN TO OVERSPREAD THE ENTIRE AREA BY 12Z WED. I
ALSO KEEP PATCHY DENSE FOG IN THE POCONOS AND CATSKILLS IN THE
HIGHER TERRAIN AS THE LL FLOW IS SERLY AND UPSLOPING UNTIL THE
HEAVIER RAIN ARRIVES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/PVF
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB/TAC
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1035 AM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADARS SHOW A BAND OF RAIN LIFTING NORTHEAST INTO CENTRAL NY AND
NRN PA IN ASSCTN WITH A SHORT WAVE THAT WAS RIPPLING NORTHEASTWARD
INTO THE NE U.S. THIS FEATURE WAS SEEN AS SOME ENHANCED CLOUD TOPS
ON THE IR IMAGERY AT THIS TIME. THIS FEATURE WILL RACE OFF TO THE
NORTHEAST BY EARLY AFTERNOON AND THE RAIN WILL GO WITH IT LEAVING
BEHIND PATCHY AREAS OF LIGHT RAIN AND DRIZZLE FOR THE REST OF THE
AFTERNOON AND MUCH OF TONIGHT. A FEW PATCHES OF STEADIER RAIN CUD
ADVECT THRU THE REGION AS PER HRRR LATE AFTERNOON/EVENING. SO WILL KEEP
CHC POPS GOING FOR AFTERNOON AND MUCH OF TONIGHT TO COVER ANY
POCKETS OF LIGHT RAIN/DRIZZLE OR A BRIEF STEADIER PD OF RAIN. MAIN
SHIELD OF RAIN ARRIVES BTWN 8 AND 12Z WED AS ONE OF THE FIRST
SIGNIFICANT MAIN WAVES RIDES NORTHEASTWARD AHEAD OF THE DIGGING
TROUGH THAT DROPS INTO THE SRN U.S LATER TONIGHT. THIS WAVE WILL
ACCELERATE A SRLY LLJ WHICH ADVECTS PLENTY OF MOISTURE NORTHWARD
INTO NY AND PA AS IT GLIDES UP THE ISENTROPES LATE TONIGHT. IN
ADDTN...UPR DVRG INCREASES AS WELL. THIS IS RECIPE FOR A
WIDESPREAD AREA OF RAIN TO OVERSPREAD THE ENTIRE AREA BY 12Z WED. I
ALSO KEEP PATCHY DENSE FOG IN THE POCONOS AND CATSKILLS IN THE
HIGHER TERRAIN AS THE LL FLOW IS SERLY AND UPSLOPING UNTIL THE
HEAVIER RAIN ARRIVES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
RAIN OVER THE AREA NOW WILL CONTINUE THROUGH THE FIRST 24 HOURS AT
LEAST. CONDITIONS MOSTLY MVFR CIGS AND VFR VSBYS.
BGM HAS IFR CIGS AND VFR VSBYS. MOST CONFIDENT HERE THAT CIGS WILL
REMAIN IFR WELL INTO WED. CIGS WILL BE AT OR CLOSE TO FLIGHT
MINIMUMS ESPECIALLY EARLY THIS MORNING. AS RAIN INCREASES TONIGHT
VSBYS MAY FALL TO IFR.
AVP WILL HAVE CIGS AROUND 1500 FT SO MVFR AND VSBYS VFR.
POSSIBILITY OF SOME IFR CIGS FIRST 3 HOURS.
ELM ALSO HAS IFR CIGS. EXTRA FUEL WITH ALTERNATE REQUIRED. CIGS
SHOULD RISE TO MVFR THIS AFTN BUT THEN FALL BACK TO IFR LATE EVE.
ITH HAS A 1K FT CIG. EXPECT THE CIG TO BECOME IFR THIS MORNING.
IMPROVEMENT TO MVFR LATE TODAY AND EVE THEN FALLING BACK TO IFR
LATE TONIGHT. VSBYS VFR BECOMING MVFR.
RME NOW MVFR CIGS BUT EXPECTED TO FALL TO IFR AT TIMES THIS
MORNING THEN FALL TO IFR TONIGHT.
SYR HAS THE BEST CONDITIONS. MVFR CIGS THROUGHOUT WITH VSBYS
FALLING TO MVFR IN STEADY RAIN STARTING THIS AFTN.
OUTLOOK...
WED TO WED NGT... MVFR LIKELY...CHANCE IFR. PERIODS OF RAIN.
THU...VFR. VERY WINDY AFTERNOON.
FRI/SAT...VFR. CHC SHRA SAT.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/PVF
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
148 AM EST TUE DEC 23 2014
.SYNOPSIS...
A SURFACE LOW DEVELOPING OVER THE NORTHERN MIDWEST IN COMBINATION
WITH A LOW MOVING UP THE EAST COAST WILL BRING A PERIOD OF LIGHT
MIXED PRECIPITATION EARLY THIS MORNING...FOLLOWED BY RAIN TODAY
THROUGH WEDNESDAY WITH MOSTLY CLOUDY SKIES. GUSTY WINDS ARE
EXPECTED CHRISTMAS DAY...WITH LINGERING RAIN SHOWERS MIXING WITH
SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TODAY/...
850 PM UPDATE...
OPTED FOR A SHORT TERM SPECIAL WEATHER STATEMENT FOR THE LOWER
TWO-THIRDS OF OUR FORECAST AREA.
RAIN SHOWERS ARE STREAMING INTO NY AND PA ATTM. IN THE NORMALLY
COOLER VALLEY LOCALES AND ON THE HIGH ELEVATIONS, TEMPERATURES ARE
BETWEEN 30 AND 34 DEGREES. THEREFORE ISOLATED LIGHT FREEZING RAIN
IS EXPECTED THROUGH THE EVENING HOURS.
JUDGING BY THE LATEST RAP AND THE CURRENT OBS TREND, TEMPERATURES
SHOULD WARM ABOVE THE FREEZING MARK BY 11 PM OR MIDNIGHT.
150 PM EST UPDATE...
CLOUDS ARE SLOWLY BUT SURELY BREAKING UP ACROSS THE WESTERN HALF
OF THE CWA THIS AFTERNOON. THE SHORTWAVE PASSING TO THE NORTH HAVE
FINALLY MANAGED TO BREAK UP THE CLOUDS AND IT FEELS GREAT TO
FINALLY SEE THE SUN... EVEN IF IT ONLY LASTS FOR A SHORT AMOUNT OF
TIME. SADLY... IT WILL NOT LAST FOR LONG AS OUR NEXT SYSTEM IS
ABOUT TO IMPACT THE REGION.
UNCERTAINTIES STILL EXIST WITH THE FRONT OF OF THE APPROACHING
STORM. ONE BIG FORECAST QUESTION FOR TONIGHT IS WILL TEMPS BE COLD
ENOUGH TO CREATE HAZARDOUS CONDITIONS. TEMPS ATTM ARE FAIRLY
WARM... AS IN 5 TO 10 DEGREES ABOVE FREEZING... EXCEPT FOR THE
HIGHER TERRAIN WHERE TEMPS HAVE RISEN CLOSE TO THE FREEZING MARK.
WE MAY COOL A FEW DEGREES WHEN THE SUN SETS DUE TO LOSS OF DIURNAL
HEATING AND WITH WET BULB EFFECT AS THE PRECIP FALLS... BUT EVEN
THEN WILL BE WARM ADVECTING.
WE DO EXPECT PRECIP TO START TONIGHT IN THE FORM OF A WINTRY MIX
OF FREEZING RAIN/SNOW/RAIN AND MAYBE SLEET. BUT THE OTHER FORECAST
PROBLEM FOR THE NIGHT IS WILL TEMPS AND ROADS STAY COLD ENOUGH
LONG ENOUGH FOR HAZARDOUS CONDITIONS TO DEVELOP FOR A PROLONGED
PERIOD OF TIME. ATTM CONFIDENCE IS NOT HIGH ENOUGH THAT THIS WILL
BE THE CASE. THUS... WE HAVE DECIDED TO NOT ISSUE AN ADVISORY FOR
TONIGHT. BELIEVE IT WOULD BE MORE APPROPRIATE FOR A SPS ISSUANCE
ENVIRONMENT.
BEFORE MIDNIGHT TONIGHT... EXPECT FREEZING RAIN/SNOW MIX. AFTER
MIDNIGHT EXPECT MORE OF WET SNOW EXCEPT FOR THE HIGHEST
ELEVATIONS... THEY MAY SEE MORE OF A VERY LIGHT FREEZING RAIN
THROUGH 4AM. BY 12Z TUESDAY EXPECT MOST ARES TO TRANSITION OVER TO
RAIN.
TEMPS THROUGH LATE TONIGHT ARE EXPECTED TO REMAIN IN THE LOW TO
MID 30S.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
255 PM EST UPDATE...
UNSETTLED WEATHER WILL BE THE MAIN THEME FOR THIS FORECAST PERIOD
AS A SFC LOW/OCCLUDED FRONT SLOWLY PUSHES IT`S WAY ACROSS THE
NORTHEAST.
TUESDAY MORNING... THE FIRST BATCH OF RAIN SHOWERS WITH THE
APPROACHING STORM SYSTEM WILL JUST START TO PUSH INTO THE AREA.
FOR THE MOST PART BY TUESDAY MORNING ALL PRECIP WILL BE RAIN. IF
THERE STILL ANY LINGERING WINTRY PRECIP FROM THE NIGHT BEFORE...
IT WILL QUICKLY TRANSITION OVER TO RAIN BY 15Z TUESDAY. TUESDAY
WILL HAVE FAIRLY LIGHT ACCUMULATIONS AROUND A HALF AN INCH OR LESS.
WAA WILL ALSO CONTINUE PREVAIL OVR THE REGION TUES INTO WED AS WE
REMAIN IN SOUTHERLY FLOW AHEAD OF THE UPPR LVL TROUGH. THIS WILL
RESULT IN UNSEASONABLY WARM TEMPERATURES OVER NY AND PA. TEMPS
WILL RISE INTO THE MID 40S ON TUESDAY AND CONTINUE TO RISE ON WED.
TEMPS ARE EXPECTED TO REACH THE UPPR 40S TO LOW 50S WED
AFTERNOON... THEN RISE INTO THE LOW TO MID 50S BY WED NIGHT. THE
REASON WHY WE WILL CONTINUE TO SEE A RISE IN TEMPS ACROSS THE CWA
WED NIGHT IS BECAUSE WE WILL HAVE A STRONG LLJ AROUND 40 TO 50
KNOTS. NOT ONLY WILL THIS INCREASE THE TEMPS IT WILL SEE A STRONG
INFLUX OF MOISTURE ACROSS THE NORTHEAST. WE ARE EXPECTED TO SEE
PWAT VALUES AROUND 4 STANDARD DEVIATIONS ABOVE NORMAL. THIS WILL
RESULT IN RAIN SHOWERS BECOMING HEAVY AT TIMES.
RAIN SHOWERS ARE EXPECTED TO PREVAIL THROUGH THE WHOLE FORECAST
PERIOD AS THE OCCLUDED FRONT WILL NOT PUSH COMPLETELY THROUGH THE
AREA TILL THURS. DO NOT EXPECT WATER PROBLEMS DUE TO LOW LIQUID
RATIOS IN SNOW PACK ACROSS OVR NY AND PA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
1230 AM UPDATE...
RAIN OVER THE AREA NOW WILL CONTINUE THROUGH THE FIRST 24 HOURS.
CONDITIONS DROPPING THIS MORNING THEN REMAINING MVFR/IFR.
BGM HAS IFR CIGS AND MVFR VSBYS. EXPECT IT TO CONTINUE INTO TUES
NGT. CIGS WILL BE AT OR CLOSE TO FLIGHT MINIMUMS ESPECIALLY EARLY
THIS MORNING.
AVP AND ITH WILL HAVE CIGS AROUND 1K FT SO IFR/MVFR AND VSBYS
MVFR. SOME IMPROVEMENT TO MVFR FOR AVP AROUND 15Z.
ELM WILL BE MVFR DUE TO CIGS AND VSBYS. EXTRA FUEL WITH ALTERNATE
REQUIRED.
RME/SYR NOW MVFR BUT EXPECTED TO FALL TO IFR CIGS BY 12Z, THEN
STAY LOW.
LLWS MARGINAL WITH 30 KT WINDS AT 2K FT. WITH NO RECENT PIREPS AND
VAD WINDS 20 KTS REMOVED LLWS AT ELM/AVP.
OUTLOOK...
TUE NGT TO WED NGT... MVFR LIKELY...CHANCE IFR. PERIODS OF RAIN.
THU...VFR. VERY WINDY AFTERNOON.
FRI/SAT...VFR. CHC SHRA SAT.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KAH
NEAR TERM...DJP/KAH
SHORT TERM...KAH
LONG TERM...JAB/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1022 PM EST WED DEC 24 2014
.SYNOPSIS...
PERIODS OF RAIN AND ISOLATED CONVECTION WILL CONTINUE THIS EVENING
AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS THE CAROLINAS AND OFF
THE COAST LATE TONIGHT. SUNSHINE IS EXPECTED TO MAKE A RETURN
CHRISTMAS DAY AS DRY HIGH PRESSURE SOUTHWEST OF THE AREA OVERSPREADS
THE CAROLINAS THURSDAY INTO THE EARLY WEEKEND. A COLD FRONT WILL
DROP INTO THE SOUTHEAST ON SUNDAY WITH A FEW WAVES OF LOW PRESSURE
DEVELOPING MONDAY THROUGH WEDNESDAY NEXT WEEK...RESULTING IN
UNSETTLED WEATHER ACROSS THE CAROLINAS.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1015 PM WEDNESDAY...THERE IS NO LONGER A SEVERE WX THREAT
ACROSS THE ILM CWA. THE BEST ORGANIZED CONVECTION IS NOW OVER THE
OFFSHORE WATERS PARALLELING THE CAROLINA COASTLINES FROM OFF
CAPE LOOKOUT SOUTHWARD TO OFF CAPE ROMAIN. THIS ACTIVITY CONTINUES
TO PULL FURTHER AWAY FROM THE U.S. MAINLAND. THIS UPDATE WILL
CONCENTRATE ON EVEN FURTHER LOWERING POPS FROM WEST TO EAST
THRUOUT THE REMAINDER OF THE EVENING AND OVERNIGHT PERIOD. THE
COLD FRONT REMAINS SLATED TO PUSH FROM WSW TO ENE ACROSS THE ILM
CWA AND OFF THE COAST DURING THE LATE EVENING HRS THRU THE
PRE-DAWN THU HOURS. LATEST HRRR INDICATES A THIN BAND OF POST
FRONTAL -SHRA TO OCCUR ACROSS THE FA...AND WILL LEAVE IN A LOW
CHANCE POP CHANCE UP TO AROUND OR JUST AFTER DAYBREAK THU. HAVE
RE-TWEAKED HOURLY SFC TEMPS AND DEWPOINTS TO ACCOUNT FOR THE
LATEST TRENDS. HAVE KEPT MORNING MINS BASICALLY THE SAME FROM THE
PREVIOUS 730 PM UPDATE. THE LOWS WILL LIKELY OCCUR AT OR 1-2 HRS
AFTER DAYBREAK THU.
PREVIOUS DISCUSSION....................................
AS OF 334 PM WEDNESDAY...A MESSY DAY CONTINUES ACROSS THE EASTERN
CAROLINAS ON THIS CHRISTMAS EVE.
CHRISTMAS TIME WEATHER IS NOT USUALLY THOUGHT OF AS TEMPS AROUND 70
WITH HEAVY RAIN AND SEVERE THUNDERSTORMS. HOWEVER...THAT IS JUST
WHAT WE ARE EXPERIENCING TODAY. A DEEP UPPER TROUGH MOVING SLOWLY
OVERHEAD THE MS VLY IS DRIVING STRENGTHENING LOW PRESSURE WHICH WILL
MOVE UP INTO THE GREAT LAKES...DRAGGING A COLD FRONT ACROSS THE AREA
LATE TONIGHT. AHEAD OF THIS FRONT...WIDESPREAD SHOWERS WITH EMBEDDED
TSTMS WILL CONTINUE...WITH SOME RESIDUAL LIGHT RAIN PERSISTING EVEN
A BIT BEHIND THE FROPA.
NO LESS THAN 3 CONVERGENT BOUNDARIES HAVE CROSSED THE ILM CWA
TODAY...THE LAST OF WHICH IS CURRENTLY MOVING INTO THE CAPE FEAR
REGION. THESE BOUNDARIES HAVE BEEN PRIMARILY CHARACTERIZED BY
TORRENTIAL RAINFALL AND FLOODING...BUT SOME ISOLATED WIND GUSTS AND
EVEN A BRIEF TORNADO HAVE ALSO OCCURRED. THE WRF HAS OUTPERFORMED
ALL OTHER HIGH-RES GUIDANCE THUS FAR TODAY...AND IS LEANED ON
HEAVILY FOR THE REMAINDER OF THE NEAR TERM. THIS SUGGESTS THAT THE
HEAVIEST RAINFALL WILL SLOWLY WIND DOWN THIS EVE AS WHAT INSTABILITY
EXISTS...AS LIMITED AS IT IS...ERODES DUE TO CONTINUED RAINFALL AND
LOSS OF DIURNAL HEATING. FORECAST PROFILES DO CONTINUE TO KEEP
DECENT SATURATION INTO LATE TONIGHT...AND THUS EXPECT MORE
STRATIFORM RAINFALL...WITH EMBEDDED CONVECTIVE ELEMENTS...TO
CONTINUE UNTIL FROPA...WHICH SHOULD OCCUR AN HOUR OR SO EITHER SIDE
OF MIDNIGHT EST. THE SEVERE THREAT IS BASICALLY 0 FOR THE REMAINDER
OF THE PERIOD...EXCEPT THE NEXT FEW HOURS WHERE THE STRONGER
CONVECTIVE ELEMENTS COULD STILL BRING DOWN A WIND GUST FROM THE
50KT/2KFT LLJ. BEHIND FROPA...SOME VERY LIGHT RAIN MAY CONTINUE INTO
MORNING...BUT IN A RAPIDLY DRYING STATE.
TEMPERATURES UNTIL FROPA WILL REMAIN NEARLY STATIONARY THANKS TO
WAA...BUT WILL BEGIN TO CRASH BEHIND THE COLD FRONT AFTER MIDNIGHT.
ONLY A FEW HOURS OF COOLING BEFORE DAYBREAK WILL LIMIT MINS TO
AROUND 50 WELL INLAND...AND NEAR 60 RIGHT ALONG THE COAST.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 334 PM WEDNESDAY...MAIN WEATHER HEADLINE IS THAT SUNSHINE IS
SLATED TO MAKE A DEBUT CHRISTMAS DAY AS SHARP DRYING FOLLOWS A
COLD FRONT SWEEPING OUT TO SEA BY DAYBREAK THURSDAY. HIGH PRESSURE
OF GULF COAST ORIGIN WILL RESULT IN WEAK COOL AIR ADVECTION AND
MAXIMUMS WILL REBOUND SLIGHT ABOVE NORMAL THURSDAY AND FRIDAY FOR
LATE DECEMBER. FRIDAY DAYBREAK LIKELY THE COLDEST TEMPS THIS
PERIOD WITH 30S WIDESPREAD ACROSS THE AREA...CLIMBING 25-28
DEGREES F BY AFTERNOON INTO THE LOW AND MIDDLE 60S UNDER SUNSHINE
AND A FEW STRANDS OF CIRRUS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM WEDNESDAY...BEGINNING OF THE WEEKEND PLEASANT BUT
HEIGHT FALLS AND AN APPROACHING COLD FRONT INTO SUNDAY WILL BRING
CLOUDS AND AN INCREASING CHANCE OF RAIN INTO SUNDAY NIGHT.
INDICATIONS ARE THE FRONT MAY STALL OVER OR NEAR THE FORECAST AREA
MONDAY THROUGH MID-WEEK...ALLOWING FOR UNSETTLED WEATHER AS A
SERIES OF WAVES TRAVEL ALONG THE STALLED BOUNDARY. BY DAYS 6/7
TUESDAY AND WEDNESDAY...A COLD FRONT LOOKS TO BRING COOLING AND
UNDERCUTS THE SW FLOW ALOFT. THIS MAY LEAD TO MURKY CONDITIONS
AND MULTIPLE CHANCES OF RAIN/SHOWERS.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...A MIXTURE OF VFR/MVFR/POSSIBLE IFR EXPECTED THROUGH
TONIGHT DUE TO VARYING LOW CIGS...AREAS OF FOG...AND SCATTERED
SHOWERS IN ASSOCIATION WITH AN APPROACHING COLD FRONT. CONDITIONS
GRADUALLY IMPROVE LATE OVERNIGHT INTO CHRISTMAS DAY AS COLD FRONT
PUSHES OFFSHORE.
LATEST RADAR IMAGERY DEPICTS LIGHT TO MODERATE SHOWERS PUSHING
EASTWARD ACROSS THE FORECAST AREA IN ASSOCIATION WITH AN APPROACHING
COLD FRONT. AS A RESULT...AREAS OF LOW CIGS AND FOG AS WELL AS
RAIN ARE CREATING MVFR AT A MAJORITY OF THE TERMINALS.
WHILE COULD NOT ENTIRELY RULE OUT BRIEF DIP IN RESTRICTIONS TO
IFR IN SOME LOCATIONS...CONFIDENCE IS LOW. SOUTH-SOUTHWEST WINDS
AOB 10 KTS...WITH OCCASIONAL GUSTS UP TO 20 KTS...WILL SHIFT TO
THE WEST BEHIND THE FRONT OVERNIGHT. BEHIND THE FRONT...EXPECT
IMPROVING CONDITIONS TO BEGIN WITH WIDESPREAD VFR BY CHRISTMAS
MORNING. EXPECT VFR AND GRADUALLY CLEARING SKIES THROUGHOUT THE
DAY...WITH WESTERLY WINDS AOB 10 KTS THROUGH THE END OF THE VALID
PERIOD.
EXTENDED OUTLOOK...VFR THURSDAY THROUGH SATURDAY. RAIN RETURNING
SUNDAY AND POSSIBLY MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 PM WEDNESDAY...BASED ON LATEST BUOY OBS...WINDS AND
SEAS TRENDS ACROSS THE ILM WATERS HAVE BASICALLY PEAKED DURING
THE AFTERNOON HRS...AND ARE NOW HOLDING MORE OR LESS STEADY.
DO EXPECT ANOTHER TEMPORARY INCREASE IN WINDS AND RESULTANT SEAS
DURING THE PRE-DAWN THU HRS...LEADING UP TO A FEW HRS AFTER
DAYBREAK. BASICALLY JUST AHEAD AND IMMEDIATELY AFTER THE CFP. AS
FOR ACTUAL WIND DIRECTIONS AND SPEEDS...WIND DIRECTIONS WILL VEER
FROM THE CURRENT SW DIRECTION...TO WESTERLY LATE TONIGHT INTO
DAYLIGHT THU. A TIGHTENED SFC PG WILL YIELD SPEEDS BETWEEN 15 TO
25 KT...WITH A FEW GUSTS TO 30 KT POSSIBLE LEADING UP TO AND JUST
AFTER THE CFP. SIGNIFICANT SEAS WILL HOLD RELATIVELY STEADY IN THE
5 TO 8 FT RANGE OVERNIGHT...HIGHEST ACROSS THE LOCAL WATERS
BETWEEN CAPE FEAR TO LITTLE RIVER INLET. AVERAGE PERIODS WILL RUN
5.0 TO 6.0 SECONDS.
PREVIOUS DISCUSSION....................................
AS OF 330 PM WEDNESDAY...TROPICAL AIRMASS CONTINUES TO ADVECT
ACROSS THE WATERS ON STRONG S/SW FLOW. ALTHOUGH DEWPOINT
TEMPERATURES HAVE RISEN TO AROUND 70 OVER THE COASTAL
WATERS...STRONG WINDS OF 20 KTS OR MORE AND AIR-TO-OCEAN TEMP
DIFFERENTIAL HAVE BEEN OUTSIDE THE CRITERIA TYPICALLY USED FOR
MARINE FOG...AND THUS HAVE DROPPED THE MARINE DENSE FOG ADVISORY.
THE SMALL CRAFT ADVISORY REMAINS UNCHANGED HOWEVER...AS WINDS AND
SEAS ARE WELL ABOVE THRESHOLDS. IN FACT...WILMINGTON HARBOR BUOY
/41108/ RECENTLY HIT 9 FT...WITH FRYING PAN SHOALS /41013/ UP TO
11 FT. LOCAL SWAN GUIDANCE INITIALIZED TOO LOW SO BUMPED FORECAST
WAVE HEIGHTS ABOUT 1 FT ACROSS ALL WATERS...AND EXPECT SEAS TO
REMAIN WELL ABOVE 6 FT UNTIL FRONTAL PASSAGE AFTER MIDNIGHT. AT
THAT TIME...WINDS WILL SHIFT QUICKLY TO THE W/NW WITH SPEEDS
CONTINUING AROUND 20 KTS. HOWEVER...THE OFFSHORE WIND COMPONENT
WILL PUSH THE HIGHEST SEAS AWAY FROM SHORE...AND SEAS WILL FALL TO
4-6 FT BY THURSDAY MORNING.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 PM WEDNESDAY...MODERATE WINDS THURSDAY WILL EASE AND
TURN NW LATER IN THE DAY. RESIDUAL WAVE ENERGY WILL TAKE MORNING
TO SETTLE AND RECOVER...AND THE ADVISORY MAY NEED TO RUN THROUGH
MOST IF NOT ALL OF MORNING. THURSDAY ANY STORMS WILL BE CONFINED
TO THE GULF STREAM AND POINTS FARTHER TO SEA. LIGHT WINDS FRIDAY
AND PLEASANT AS SURFACE HIGH PRESSURE MOVES NEARLY OVERHEAD OR JUST
NORTH OF THE AREA. WINDS FRIDAY 10 KT OR LESS FROM NE-ESE.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 330 PM WEDNESDAY...SATURDAY FEATURES A SURFACE HIGH
MIGRATING OFFSHORE AND WEAK RETURN WINDS FROM THE S. A COLD FRONT
WILL DROP FROM THE N VERY LATE IN THE PERIOD MONDAY NIGHT AND
BRING INCREASING NE WINDS...ALTHOUGH AT THIS TIME AN ADVISORY MAY
NOT BE NEEDED. RAIN MAY REDUCE VSBYS BELOW 2-3 NM SUNDAY NIGHT
THROUGH MONDAY IN PERIODS OF LIGHT RAIN OR DRIZZLE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/JDW
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
232 PM EST TUE DEC 23 2014
.SYNOPSIS...A COLD AIR DAMMING RIDGE WILL REMAIN LOCKED IN PLACE
EAST OF THE APPALACHIANS THROUGH THIS EVENING. A WARM FRONT WILL
LIFT NORTHWARD THROUGH THE AREA WEDNESDAY MORNING AS A LOW PRESSURE
SYSTEM STRENGTHENS WEST OF THE MOUNTAINS. AN ASSOCIATED COLD FRONT
WILL SURGE EASTWARD ACROSS THE CAROLINAS WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM TUESDAY...
CAD WEDGE REMAINS STRONGLY ANCHORED IN PLACE AS EVIDENT FROM THE
VERY STRONG INVERSION ON THE CURRENT RAP FORECAST SOUNDINGS. THIS
DOES NOT CHANGE HARDLY AT ALL OVERNIGHT AND SO THE FOG/MIST AND LOW
CEILINGS WILL ALSO CONTINUE THROUGH TONIGHT. AFTER 00Z A WARM FRONT
WILL BEGIN ITS NORTHWARD ADVANCEMENT THROUGH OUR CWA AND WITH IT
WILL COME A PERIOD OF RAIN BEGINNING ABOUT 00Z IN THE SOUTH AND A
COUPLE HOURS LATER IN THE NORTH. THIS FIRST BOUT OF RAIN WILL LAST
UNTIL 6-8Z BEFORE HIGH RESOLUTION MODELS PREDICT A LULL IN
PRECIPITATION. DURING THIS LULL EXPECT FOG TO BECOME AN ISSUE WITH
AREAS OF 1/2 SM VISIBILITIES AND PROBABLY LESS IN SOME SPOTS. WOULD
NOT BE SURPRISED TO HAVE TO ISSUE A DENSE FOG ADVISORY SOMETIME
AFTER 6Z THROUGH DAYBREAK FOR THE ENTIRE AREA. A SECOND WAVE OF
PRECIPITATION WILL APPROACH THE AREA FROM THE SOUTHWEST CLOSER TO
DAYBREAK. THIS AGAIN IS ACCORDING TO HIGH RESOLUTION
MODELS...WHEREAS THE GFS AND ECMWF HAVE A MORE CONTINUOUS
PRECIPIATION PATTERN OVERNIGHT. HAVE HEDGED THE FORECAST TOWARDS THE
HIGH RES MODELS. EARLIER INDICATIONS WERE THAT SOME ELEVATED
INSTABILITY MIGHT CREATE ENOUGH LIFT FOR SOME THUNDERSTORMS THIS
EVENING. WHILE CURRENT SHORT TERM MODELS ARE STILL SHOWING DECENT
MID LEVEL LAPSE RATES FOR THIS TIME OF YEAR...THEY ARE LACKING THE
INSTABILITY THAT WAS THERE IN THIS MORNINGS RUN. AS A RESULT HAVE
TAKEN MENTION OF THUNDER OUT OF THE FORECAST FOR NOW. RADAR IS
HOWEVER DEPICTING SOME LIGHTNING STRIKES IN THE CHARLOTTE AREA AND
DOWN ALONG THE COAST SOUTH OF WILMINGTON. TRENDS IN THE ACTIVITY
OVER THE PAST HOUR OR SO ARE WEAKENING SO WHILE IT IS NOT IMPOSSIBLE
THAT WE WILL SEE A LIGHTNING STRIKE OR TWO...THE CHANCES ARE GETTING
LESS LIKELY.
TEMPERATURES WILL FOLLOW A NON-DIURNAL PATTERN THIS EVENING INTO THE
OVERNIGHT HOURS AS THE WARM FRONT MOVES NORTH...EXPECT TEMPERATURES
TO RISE OVERNIGHT...AND LOWS ARE MOST LIKELY TO OCCUR DURING THE
EVENING HOURS TONIGHT IN THE LOW TO MID 40S BEFORE RISING OVERNIGHT.
THE WARMING TREND WILL BE VERY MUTED IN THE TRIAD WHERE THE WARM AIR
WILL END UP RISING UP OVER THE COLD DOME LOCKED IN BY THE CAD WEDGE.
THEREFORE EXPECT LOW 40S IN THE TRIAD NEAR DAYBREAK WITH MUCH WARMER
MID TO UPPER 50S IN THE SOUTH AND EAST. THE PROGRESSION OF
TEMPERATURES WILL DEPEND ON THE FRONTAL ADVANCEMENT AND THEREFORE
HOURLY TEMPERATURES OVERNIGHT ARE A LOW CONFIDENCE FORECAST AT BEST.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 200 PM TUESDAY...
...ACTIVE WEATHER DAY ON TAP WITH CAD...HEAVY RAIN AND A SMALL
THREAT OF SEVERE WEATHER IN THE COASTAL PLAIN...
NWP GUIDANCE IS IN GOOD AGREEMENT WITH THE OVERALL EVOLUTION OF THE
WEATHER PATTERN DURING THE SHORT TERM PERIOD WITH A HIGH AMPLITUDE
DIGGING TROUGH AT 500 HPA THAT EXTENDS INTO THE WESTERN GULF OF
MEXICO AT DAYBREAK WEDNESDAY. THE TROUGH CLOSES OFF WITH AN UPPER
LOW DURING THE MORNING AS IT LIFTS FROM NEAR KSTL TO NORTHEAST OF
KDET TOWARD MIDNIGHT AS THE TROUGH AXIS SLOWLY SHIFTS EAST TO NEAR
OR JUST WEST OF THE APPALACHIANS BY DAYBREAK CHRISTMAS MORNING. AT
THE SURFACE...AN AREA OF LOW PRESSURE DEVELOPING IN THE LOWER OH
VALLEY RAPIDLY DEEPENS AS IT MOVES TO NORTH OF THE GREAT LAKES AFTER
MIDNIGHT. THE ATTENDANT COLD FRONT REACHES THE SOUTHWESTERN
APPALACHIANS AROUND MIDDAY WEDNESDAY...THE TRIANGLE TOWARD MIDNIGHT
AND THE COAST BY DAYBREAK CHRISTMAS MORNING.
AFTER AFTER A PREDAWN LULL...WIDESPREAD RAIN WITH EMBEDDED HEAVIER
SHOWERS WILL OVERSPREAD CENTRAL NC AFTER DAYBREAK FROM THE SOUTHWEST
AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. THE RAIN WILL
OVERWHELM MUCH OF CENTRAL NC DURING THE MORNING INTO THE EARLY
AFTERNOON HOURS. GUIDANCE DIFFERS IN THE HANDLING OF THE DETAILS OF
THE PRECIPITATION WITH THE CONVECTION ALLOWING MODELS (CAMS)
SUGGESTING THE CONVECTION WILL OUTRUN THE COLD FRONT AND THE LAGGING
UPPER TROUGH WITH THE LINE OF CONVECTION REACHING THE COASTAL PLAIN
TOWARD MID/LATE AFTERNOON WITH A LULL BEHIND THE LINE. OTHER
CONVECTION PARAMETERIZED MODELS SHOW A MORE OR LESS CONTINUOUS
PERIOD OF PRECIPITATION THROUGH THE LATE NIGHT HOURS. FEEL THE CAMS
DEPICT THE EVOLUTION OF THE EVENT MORE REALISTICALLY AND WILL USE
THEM TO CONSTRUCT THE GRIDS AND HIGHLIGHT A BAND OF HEAVIER SHOWERS
AND THUNDERSTORMS. PRECIPITATION CHANCES WILL DECREASE DURING THE
EVENING IN A RELATIVE LULL BETWEEN THE DEPARTING SQUALL LINE AND THE
APPROACHING UPPER TROUGH. GUIDANCE HAS TRENDED SLOWER WITH THE
PASSAGE OF THE COLD FRONT AND THE UPPER TROUGH AND SUGGEST ANOTHER
LINE OF SHOWERS WILL LIKELY REDEVELOP IN THE WESTERN PIEDMONT JUST
PRIOR TO MIDNIGHT AND EXPAND IN COVERAGE AND INTENSITY AS IT MOVES
EAST AND REACHES THE COASTAL PLAIN WELL AFTER MIDNIGHT.
THE THREAT FOR SEVERE CONVECTION WED AFTERNOON IS LIMITED IN CENTRAL
NC BUT HAS BEEN TRENDING UPWARD SLIGHTLY. THE AMOUNT OF BOUNDARY
LAYER DESTABILIZATION IS STILL RATHER SMALL BUT THE MOST RECENT RUN
OF THE SREF SHOWS ALL 21 MEMBERS WITH AT LEAST SOME SFC CAPE AT 18-
20Z AT KFAY WITH NEARLY HALF OF THE MEMBERS SHOWING CAPE VALUES
GREATER THAN 250 UNITS. THESE ARE STILL PRETTY MEAGER VALUES BUT
THEY HAVE BEEN TRENDING UPWARD AND COMBINED WITH BULK SHEAR VALUES
AROUND 50KTS...A LIMITED THREAT OF SEVERE WEATHER IS PRESENT IN THE
COASTAL PLAIN AND SANDHILLS DURING THE MID TO LATE AFTERNOON HOURS
WEDNESDAY. FURTHER NORTH AND WEST THE BOUNDARY LAYER IS MORE STABLE
SO CONVECTION IS LIKELY TO INTENSIFY NOTABLY AS IT PUSHES EAST OF
U.S. 1.. MODEL CONSENSUS EXPERIMENTAL SHERB HSLC VALUES ARE ELEVATED
IN THE 0.7 TO 0.9 RANGE AT 18Z ON WEDNESDAY IN THE EASTERN PIEDMONT
AND SOUTHERN COASTAL PLAIN OF NC...NEAR BUT LESS THAN THE CRITICAL
VALUE OF 1. THE LIMITING FACTOR IN ADDITION TO INSTABILITY IS THE
LAGGING UPPER TROUGH AND ITS HEIGHTS FALLS AND INCREASED LAPSE
RATES.
AS IS TYPICALLY THE CASE...THE INSITU COLD AIR DAMMING WILL PERSIST
IN THE NORTHWEST PIEDMONT LONGER THAN MOST OF THE NWP GUIDANCE
SUGGESTS...ALTHOUGH THE HIGH RES WINDOW SIMULATIONS HOLD ONTO COOLER
TEMPS LONGER COMPARED TO THE NAM/GFS/EC. EVENTUALLY THE APPROACHING
COLD FRONT WILL SCOUR OUT THE CAD AIRMASS IN THE TRIAD BUT THE
ASSOCIATED MIXING WILL ACTUALLY PRODUCE A WINDOW OF WARMING
TEMPERATURES DURING THE EVENING THROUGH MIDNIGHT.
ELSEWHERE...TEMPERATURES WILL RISE INTO THE 60S WITH SOME LOWER 70S
IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN BY AFTERNOON.
STILL SOME CONCERN FOR THE POTENTIAL OF FLASH FLOODING AND EVENTUAL
MINOR RIVER FLOODING BUT THE PRECIPITATION IS LIKELY TO ARRIVE IN
MULTIPLE WAVES DURING THE PERIOD. IN ADDITION...TIME LAGGED
ENSEMBLES FOR BOTH THE NAM AND GFS SUGGEST RECENT RUNS ARE TRENDING
WITH LOWER QPF...GENERALLY RANGING BETWEEN 1.0 AND 1.5 INCHES. A
MORE GENERAL URBAN AND SMALL STREAM THREAT SEEMS MOST PROBABLE AT
THIS POINT. SEE HYDRO DISCUSSION BELOW FOR MORE DETAILS. -BLAES
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 215 PM MONDAY...
THURSDAY AND THURSDAY NIGHT: THERE MAY BE A FEW SHOWERS IN THE
PROCESS OF EXITING THE FAR EASTERN ZONES CHRISTMAS MORNING...
OTHERWISE EXPECT A WEST TO EAST CLEARING TRENDING IN THE WAKE OF THE
EXITING COLD FRONT. ADDITIONALLY...DEEPENING SURFACE LOW LIFTING
NEWD INTO SE CANADA WILL RESULT IN BREEZY CONDITIONS ON CHRISTMAS
DAY...WITH WEST-NORTHWESTERLY WINDS GUSTING INTO THE UPPER TEENS TO
LOWER 20S...STRONGEST DURING THE FIRST HALF OF THE DAY. WEAK CAA
BEHIND THE FRONT WILL STILL ALLOW FOR SEASONABLY MILD TEMPERATURES.
HIGHS IN THE MID 50S NW TO LOWER 60S SE. LOWS IN THE LOWER TO MID
30S.
FRIDAY THROUGH SATURDAY: DRY CONDITIONS WILL PERSIST WITH ABOVE
NORMAL TEMPERATURES THROUGH SATURDAY AS HIGH PRESSURE OVER THE THE
GULF COAST STATES BUILDS OVER THE AREA ON FRIDAY...WITH LIGHT SWLY
RETURN FLOW ON SATURDAY AS THE HIGH CENTER SHIFTS OFFSHORE. HIGHS
RANGING FROM THE UPPER 50S NW TO MID 60S SE. LOWS FRIDAY NIGHT IN
THE LOWER TO MID 30S.
SATURDAY NIGHT THROUGH TUESDAY: WHILE THE NEXT TROUGH/SYSTEM TO
IMPACT THE REGION IS NOT COMPLETELY RESOLVED YET...THERE IS AT LEAST
A GENERAL CONSENSUS THAT IT WILL BE A WET LATTER HALF OF THE
WEEKEND/EARLY NEXT WEEK.
ANOTHER BATCH OF PACIFIC SHORTWAVE ENERGY IS FORECAST TO EMERGE FROM
THE SOUTHERN ROCKIES ON SATURDAY AND IS PROGGED TO PROGRESS EASTWARD
INTO THE SOUTHERN PLAINS/ARKLATEX REGION SATURDAY NIGHT AND INTO
SUNDAY...EVENTUALLY DAMPENING AS IT ROUNDS THE BASE OF THE LONG WAVE
TROUGH AND MOVES INTO THE REGION LATE SUNDAY-MONDAY. IN
RESPONSE...WEAK SFC CYCLOGENESIS ENSUES ON THE SOUTHERN END OF A
COLD FRONT...INVOF THE LOWER MS VALLEY...THAT WILL EVENTUALLY RIDE
NORTHEASTWARD TOWARDS THE SOUTHERN MID-ATLANTIC REGION...SUPPORTING
WHAT COULD END BEING ANOTHER SIGNIFICANT WIDESPREAD RAIN EVENT FOR
THE CAROLINAS SUNDAY-SUNDAY NIGHT. IN SHORT...THE MORE
AMPLIFIED/PHASED EC SOLUTION WOULD SUPPORT A SLOWER MORE CONVECTIVE
RAINFALL SCENARIO AS THE AREA OF LOW PRESSURE TRACKS THROUGH THE
SOUTHERN APPALACHIANS. THE MORE PROGRESSIVE GFS DEPICTS YET ANOTHER
OVERRUNNING DAMMING EVENT IN THE WAKE OF AN EARLIER NORTHERN STREAM
COLD FRONTAL PASSAGE SATURDAY NIGHT AS AN AREA OF LOW PRESSURE
TRACKS FROM THE NORTHERN GULF TO OFF THE SOUTHEAST COAST. GIVEN
THESE LARGE MODEL DIFFERENCES..FORECAST WILL REFLECT A
MODEL/ENSEMBLE BLEND WITH CHANCE POPS SUNDAY AND SUNDAY NIGHT WITH
NO P-TYPE CONCERNS. TEMPERATURES DROPPING BACK TO NEAR NORMAL GIVEN
WIDESPREAD RAIN AND CLOUDS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 100 PM TUESDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE OF LIFR OR WORSE CONDITIONS
THROUGH THE END OF THE TAF PERIOD. CONDITIONS THIS AFTERNOON HAVE
BEEN VARIABLE AS FAR AS VISIBILITIES GO...RANGING FROM 1/4 SM UP TO
AS HIGH AS 5SM BUT THE COMMON DENOMINATOR HAS BEEN VERY LOW CEILINGS
BELOW 500 FEET. THIS SHOULD CONTINUE THROUGH THE TAF PERIOD. WINDS
THIS AFTERNOON ARE FAIRLY CALM BUT WILL BE LIGHT AND VARIABLE
OVERNIGHT SHIFTING TO A MORE SOUTHERLY DIRECTION BY WEDNESDAY
AFTERNOON. LATE IN THE TAF PERIOD WIND SPEEDS COULD PICK UP TO NEAR
10 KTS. NOT MUCH PRECIPITATION IN THE AREA OTHER THAN MIST OR
DRIZZLE RIGHT NOW BUT THAT WILL CHANGE THIS EVENING AS RAIN WILL
MOVE UP FROM THE SOUTHWEST AND WILL BEGIN TO AFFECT TAF SITES AROUND
00Z WITH KRDU AND KRWI A COUPLE OF HOURS LATER. THIS FIRST ROUND OF
RAIN WILL LAST UNTIL ABOUT 6-8Z AND THEN THERE IS EXPECTED TO BE A
LULL IN PRECIPIATION. DURING THIS LULL...EXPECT WIDESPREAD FOG
ACROSS THE CWA WITH VISIBILITIES AS LEAST AS LOW AS 1/2 A MILE BUT
WOULD COUNT ON SOME AREAS OF DENSE FOG OF LESS THAN A 1/4 MILE
VISIBILITY. AROUND DAYBREAK...A SECOND ROUND OF PRECIPITATION IS
PROGGED TO MOVE INTO THE AREA WHICH MAY HELP IMPROVE VISIBILITIES A
LITTLE BUT CEILINGS WILL STILL BE BELOW 500 FEET.
LONG TERM: PERIODS OF PRECIPITATION...AND ADVERSE AVIATION
CONDITIONS WILL PERSIST THROUGH WEDNESDAY NIGHT INTO THURSDAY
MORNING BEFORE MOVING OFF TO THE EAST. THE NEXT CHANCE AFTER THAT
FOR ADVERSE CONDITIONS WILL BE WITH A SOUTHERN STREAM SYSTEM THAT
WILL MOVE INTO CENTRAL NC FOR SUNDAY INTO MONDAY.
&&
.HYDROLOGIC DISCUSSION /TONIGHT THROUGH THURSDAY/...
AS OF 210 PM TUESDAY...
THERE HAVE BEEN THREE FAIRLY SIGNIFICANT RAINFALL EVENTS OVER
CENTRAL NORTH CAROLINA DURING THE PAST TWO WEEKS...WITH HEAVIER
RAINFALL AMOUNTS (>1 INCH TOTAL) GENERALLY FROM THE TRIANGLE AND
FAYETTEVILLE AREAS EAST TO THE COAST. AS A RESULT...RELATIVE SOIL
MOISTURE IS UNIFORMLY HIGH THROUGH A 200 CM DEEP COLUMN...WHICH WILL
PROMOTE FASTER RUNOFF AS WELL AS A HIGHER PERCENTAGE OF RAINFALL-TO-
RUNOFF FROM THE UPCOMING EVENT TONIGHT THROUGH CHRISTMAS MORNING.
CURRENT QUANTITATIVE PRECIPITATION FORECASTS RANGE FROM 1.25 INCHES
TO NEARLY 2 INCHES...AND HAVE BEEN TRENDING DOWNWARD WITH SUCCESSIVE
MODEL RUNS. AT THIS TIME...OUR PREFERRED RAINFALL FORECAST IS FOR
WIDESPREAD AMOUNTS OF LESS THAN 1.5 INCHES...WHICH WILL CAUSE
MAINSTEM RIVERS TO RISE SEVERAL FEET FROM CHRISTMAS DAY INTO THE
WEEKEND...BUT RIVER FORECAST POINTS WOULD CREST BELOW MINOR FLOOD
STAGE. WIDESPREAD RAIN NEARER THE HIGH END OF THIS RANGE (1.75 TO
2 INCHES) WOULD LIKELY PRODUCE MINOR FLOODING ON EASTERN RIVERS...
PARTICULARLY THE HAW...NEUSE...AND TAR RIVERS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...ELLIS
SHORT TERM...BLAES
LONG TERM...CBL
AVIATION...ELLIS
HYDROLOGY...MLM/BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 AM EST TUE DEC 23 2014
.SYNOPSIS...A COLD AIR DAMMING RIDGE WILL REMAIN LOCKED IN PLACE
EAST OF THE APPALACHIANS THROUGH THIS AFTERNOON. A WARM FRONT WILL
LIFT NORTHWARD THROUGH THE REGION TONIGHT AND EARLY WEDNESDAY AS A
STRONG COLD FRONT APPROACHES FROM THE WEST. THIS FRONT WILL MOVE
EAST THROUGH OUR REGION WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1025 PM MONDAY...
TONIGHT: WV SATELLITE AND UPPER AIR DATA THIS EVENING REVEAL A
STRONGLY DIGGING/AMPLIFYING TROUGH OVER THE EASTERN ROCKIES...WITH
PERTURBED SOUTHWESTERLY FLOW EAST OF THE TROUGH AXIS FROM THE EAST
PACIFIC TO THE EASTERN US COAST. ONE SUCH PERTURBATION AND
ASSOCIATED AREA OF SHOWERS FROM NE GA AND THE SC UPSTATE WILL TRACK
NE ACROSS THE WESTERN PIEDMONT TONIGHT...AND IN CONJUNCTION WITH A
STRONG 925 MB FRONTAL ZONE OVER THE PIEDMONT CHARACTERIZED BY A 13 C
TEMP DIFFERENTIAL BETWEEN GSO AND MHX PER 00Z RAOB DATA...WILL
SUPPORT PERIODS OF RAIN OVER THE WESTERN PIEDMONT. UPSTREAM HOURLY
RAINFALL AMOUNTS SUPPORT THE LATEST RAP AND HRRR QPF OF AROUND A
TENTH TO TWO TENTHS OF ADDITIONAL RAIN...VERSUS LIGHTER AMOUNTS
NOTED BY THE EC/GFS/NAM. OTHERWISE AND ELSEWHERE...PERIODS OF
NORTHERLY 5-10 MPH WIND-BLOWN DRIZZLE...AND A CHANCE OF MEASURABLE
RAIN...WILL PREVAIL. A SATURATED AND NEAR-FULLY WET-BULBED LOWEST
SEVERAL THOUSAND FT...OWING TO CAD FROM A PARENT 1032 MB SURFACE
HIGH NEAR NOVA SCOTIA...WILL SUPPORT LITTLE VARIATION IN
TEMPERATURES FROM THEIR 10 PM READINGS IN THE MIDDLE 30S TO AROUND
40 DEGREES. -MWS
TUESDAY...NO MECHANISM NOTED TO SCOUR OUT THE CAD AIR MASS SO EXPECT
A CONTINUATION OF THE EXTENSIVE OVERCAST WITH PATCHES OF LIGHT
RAIN/DRIZZLE. EXPECT TO SEE A NOTEWORTHY INCREASE IN RAIN COVERAGE
AND INTENSITY LATE IN THE DAY AS S/W (NOW CROSSING CENTRAL TX)
ADVANCES EAST TOWARD OUR REGION. THIS FEATURE WILL INCREASE
DIVERGENCE ALOFT AS WELL AS INCREASE ISENTROPIC UPGLIDE IN THE LOWER
LAYERS OF THE ATMOSPHERE. THESE FACTORS IN COMBINATION WITH PRECIP
WATER VALUES WELL ABOVE NORMAL SHOULD RESULT IN AREAS OF MODERATE-
BRIEFLY HEAVY RAINFALL LATE IN THE DAY OR EARLY EVENING ACROSS THE
WESTERN PIEDMONT.
DAYTIME TEMPS WILL REMAIN WELL BELOW NORMAL. USED THE HIGH RES WRF-
ARW FOR HOURLY TEMPS AS GFS-BASED GUIDANCE APPEARS TO BE ERODING THE
CAD (AND ITS LINGERING EFFECTS) TOO QUICKLY. TEMPS BY LATE AFTERNOON
SHOULD VARY FROM THE UPPER 30S/LOWER 40S OVER THE PIEDMONT TO NEAR
50 OVER THE FAR SE.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 240 AM TUESDAY...
...WARMER... BREEZY... WITH HEAVY RAIN THREAT WEDNESDAY INTO
WEDNESDAY EVENING...
OVERALL... MODELS ARE IN GOOD AGREEMENT WITH THE STORM TRACK TO THE
WEST OF THE APPALACHIANS. WEDNESDAY WILL BEGIN WITH LINGERING CAD IN
THE PIEDMONT DAMMING REGION... BUT A WARM FRONT WILL BE SURGING
NORTHWARD WITH WIDESPREAD RAIN... LOCALLY HEAVY EARLY IN THE DAY.
THE WARM FRONT WILL SURGE INTO VA IN THE AFTERNOON... THEN A LINE OF
CONVECTION CAN BE EXPECTED WITH THE MAIN COLD FRONT LATER IN THE DAY
INTO THE EVENING.
THE AFOREMENTIONED WARM FRONT IS EXPECTED TO BE LIFTING NORTHWARD
THROUGH THE PIEDMONT WEDNESDAY MORNING WITH CATEGORICAL POP. THE NW
QUADRANT OF THE PIEDMONT WILL BE THE LAST REGION TO HANG ON TO THE
RESIDUAL CAD WITH LOW CEILINGS AND VISIBILITIES/COOL STABLE SURFACE
TEMPERATURES BEFORE EVEN THAT REGION BREAKS INTO THE WARM SECTOR
WEDNESDAY AFTERNOON. THERE IS STILL A QUESTION OF TIMING OF THE WARM
FRONT WHICH WILL AFFECT HIGH TEMPERATURES IN THE PIEDMONT WEDNESDAY.
IN ADDITION... SOME ENSEMBLE MEMBERS OF BOTH THE GFS AND EC INDICATE
SHOWERY CONDITIONS AND LOW CEILINGS EVEN AFTER THE WARM FRONT MOVES
INTO VA. HOWEVER... A LULL IN SIGNIFICANT RAINS IS EXPECTED AFTER
THE WARM FRONT IN THE EAST AND SOUTH. HIGHS SHOULD REACH WELL INTO
THE 60S AND EVEN SOME 70S DOWN EAST. SOUTHWEST WINDS WILL INCREASE
TO 10-20 MPH.
A PRE-FRONTAL CONVECTION LINE AND/OR A LINE OF CONVECTION WITH THE
ACTUAL COLD FRONT WILL FOLLOW LATER WEDNESDAY INTO WEDNESDAY EVENING
(PROGRESSING FROM WEST TO EAST ACROSS THE STATE). SOME LOCALLY VERY
HEAVY RAIN CAN BE EXPECTED. A FLASH FLOOD WATCH HAS BEEN CONSIDERED.
HOWEVER... GIVEN THE RELATIVELY DRY ANTECEDENT CONDITIONS...
ESPECIALLY IN THE WEST DURING THE PAST MONTH - FLASH FLOOD GUIDANCE
REMAINED HIGH. THE QPF FOR STORM TOTAL OF 2-3 INCHES WOULD GET MOST
AREAS NEAR THE THRESHOLD. HOWEVER... GIVEN THAT THE HEAVIEST RAIN
SHOULD COME IN 2-3 ROUNDS... THE GROUND SHOULD BE ABLE TO RECOVER
SOMEWHAT IN BETWEEN THE HEAVIEST RAINS. THEREFORE... LOCAL RUNOFF
PROBLEMS WILL LIKELY BE THE END RESULT WHICH SHOULD AFFECT MOSTLY
URBAN AREAS. WE WILL ADD THIS TO THE HAZARDOUS WEATHER OUTLOOK. THE
FINAL LINE OF CONVECTION MAY DROP LOCAL 1 TO 1.5 INCHES IN AN
HOUR... SO SOME URBAN FLASH FLOODING MAY OCCUR IF THIS HAPPENS. THIS
WOULD MOST LIKELY OCCUR LATE WEDNESDAY IN THE WEST... AND LATE
AFTERNOON INTO THE EVENING IN THE EAST.
SEVERE STORMS ARE NOT EXPECTED AT THIS TIME. HOWEVER... GUSTY WINDS
TO 40-45 MPH ARE LIKELY TO OCCUR WITH THE FINAL LINE OF CONVECTION
WEDNESDAY AFTERNOON AND EVENING. MLCAPES IN ADVANCE OF THE FRONT
SHOULD BE HELD DOWN BY THE EXTENSIVE MOISTURE AND CLOUDS/SHOWERS
KEEPING THE SEVERE THREAT LIMITED.
SENSIBLE WEATHER WILL BE FOR RAIN INTO WEDNESDAY MORNING... TAPERING
TO SCATTERED SHOWERS DURING THE DAY. BECOMING BREEZY FROM THE
SOUTHWEST AND TEMPS RISING INTO THE 60S TO LOWER 70S. ANOTHER LINE
OF TWO OF SHOWERS/ISO THUNDERSTORMS SOME WITH GUSTY WINDS WED
AFTERNOON INTO THE EVENING. PARTIAL CLEARING WEDNESDAY NIGHT WITH
LOWS IN THE 40S TO LOWER 50S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 235 AM TUESDAY...
MILD AND DRIER THURSDAY INTO SATURDAY...
BREEZY WEST WINDS CHRISTMAS DAY WITH SKIES BECOMING PARTLY TO MOSTLY
SUNNY. MILD HIGHS IN THE 50S TO LOWER 60S EXPECTED. WINDS SHOULD
DIMINISH DURING THE MID TO LATE AFTERNOON AS THE PRESSURE GRADIENT
WEAKENS AS THE SURFACE HIGH BUILDS IN FROM THE GULF COAST STATES.
MILD TEMPERATURES AND MOSTLY CLEAR SKIES ARE EXPECTED FRIDAY INTO
SATURDAY AS HIGH PRESSURE BUILDS OVER THE SOUTHEAST STATES.
EXPECT LOWS IN THE 30S AND HIGHS IN THE 50S.
MODEL SPREAD STILL INCREASES THROUGH THE WEEKEND...WITH THE EC
CONTINUING MUCH DEEPER WITH THE NEXT MID/UPPER LEVEL
TROUGH...RESULTING IN A STRONGER SURFACE WAVE THAT WOULD BRING YET
ANOTHER WET AND UNSETTLED PERIOD SUNDAY INTO MONDAY. WHEN THE
ENSEMBLES ARE CONSIDERED... A MUCH WEAKER WAVE RESULTS. THEREFORE...
WE WILL SIMPLY INDICATE AN INCREASE IN CLOUDINESS THEN WITH COOLER
TEMPERATURES. THERE MAY BE AN IMPORTANT STORM IF THE EC DOES INDEED
VERIFY LATER SUNDAY INTO EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 715 PM MONDAY...
AVIATION CONDITIONS WILL REMAIN POOR WELL ON THROUGH TONIGHT AND
TUESDAY...WITH PERIODS OF RAIN/DRIZZLE AND A LIGHT NORTHEASTERLY
WIND ALONG WITH THE ALREADY LOW CLOUDS AND LIMITED VSBYS. THERE IS
HIGH CONFIDENCE OF LIFR CONDITIONS THROUGH THE NIGHT AND THERE MAY
ALSO BE SOME VLIFR CONDITIONS RESULTING FROM FOG BETWEEN 06Z AND 12Z.
THERE WILL BE NO CHANGE IN THE AIRMASS OVER NC ON TUESDAY...SO ONLY
MINIMAL IMPROVEMENT IN CONDITIONS IS EXPECTED. CEILINGS MAY LIFT A
LITTLE DURING THE AFTERNOON ALLOWING IFR CONDITIONS TO DEVELOP...BUT
CONFIDENCE IN THIS IS LOW GIVEN HOW LITTLE CONDITIONS CHANGED
EARLIER TODAY. PERIODS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE.
OUTLOOK... AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
APPROACH THE REGION TUESDAY NIGHT AND WEDNESDAY...LEADING TO AN
INCREASED CHANCE OF SHOWERS...ALONG WITH GUSTY WINDS AND A FEW
ISOLATED THUNDERSTORMS (MAINLY OVER EASTERN NC). THUS...AVIATION
CONDITIONS WILL REMAIN POOR THROUGH AT LEAST WEDNESDAY....BEFORE A
COLD FRONT CROSSES THE AREA LATE WEDNESDAY NIGHT AND EARLY THURSDAY.
BEHIND THE FRONT...BLUSTERY WESTERLY WINDS WILL OCCUR CHRISTMAS DAY
WITH GUSTS 30-35KTS POSSIBLE. OTHERWISE VFR CONDITIONS EXPECTED TO
RETURN CHRISTMAS DAY AND PERSIST THROUGH SATURDAY.
&&
.HYDROLOGY...
AS OF 245 AM TUESDAY...
THIS IS THE OUTLOOK FOR AREA RIVERS THROUGH THE UPCOMING STORM.
RAINFALL OVER THE PAST 24 HOURS RANGED FROM AROUND 0.10 IN THE
WESTERN PIEDMONT TO OVER 1 INCH IN THE NORTHEAST PIEDMONT AND
COASTAL PLAIN. THIS WILL PRODUCE ONLY MINOR RISES ON THE
TAR/ROANOKE/NEUSE AND CAPE FEAR RIVERS.
THIS IS THE THIRD SIGNIFICANT RAINFALL EVENT (>0.5 INCHES) OVER THE
AREA SINCE 12/10. RELATIVE SOIL MOISTURE PERCENTAGES IN THE 0-200 CM
COLUMN HAVE BEEN INCREASING...WITH HIGHER WATER PERCENTILES NEARER
THE SURFACE. THEREFORE MORE RUNOFF IS EXPECTED FROM OUR UPCOMING
RAIN EVENT.
CURRENT QUANTITATIVE PRECIPITATION FORECASTS FROM THE MODELS
INCLUDING THE GEFS AND NAEFS ENSEMBLES ARE IN AGREEMENT WITH 1 TO
1.5 INCHES TONIGHT THROUGH EARLY WEDNESDAY... THEN ANOTHER ROUND OF
LOCALY 1+ INCH TOTALS LATER WEDNESDAY AND WEDNESDAY NIGHT WITH THE
COLD FRONT.
STORM TOTAL RAINFALL OF 2 TO LOCALLY 3 INCHES FOR THE ENTIRE EVENT
ENDING WEDNESDAY NIGHT WILL POTENTIALLY CAUSE MINOR FLOODING ON THE
NEUSE RIVER AND TAR RIVER LATE ON CHRISTMAS DAY. HOWEVER... IT WOULD
BE LOW IMPACT WITH THOSE RIVERS LIKELY ONLY REACHING MINOR FLOOD
STAGE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$ SYNOPSIS...VINCENT
NEAR TERM...MWS/WSS
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...BLS
HYDROLOGY...MLM/BADGETT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
248 PM CST TUE DEC 23 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
THE MAIN CONCERN IN THE SHORT WILL BE LINGERING LIGHT SNOW
CHANCES THIS AFTERNOON/EVENING...WITH CHANCES FOR RAIN OR SNOW ON
WEDNESDAY.
AFTERNOON REGIONAL RADAR MOSAIC SHOWS LIGHT SNOW ACROSS PARTS OF
WESTERN AND CENTRAL NORTH DAKOTA. THE SNOW HAS DIMINISHED IN
COVERAGE OVER THE PAST COUPLE HOURS...AND SHORT TERM MODELS
SUPPORT THAT TREND. WILL CARRY ONLY SMALL POPS WITH LITTLE TO NO
ADDITIONAL SNOW ACCUMULATION EXPECTED.
CONSIDERED ADDING PATCHY FOG IN THE WEST IN PROXIMITY TO A SURFACE
RIDGE AXIS. THE LATEST HRRR INDICATES THERE IS A CHANCE OF REDUCED
VISIBILITIES LATE TONIGHT INTO EARLY WEDNESDAY...BUT WAS NOT QUITE
CONFIDENT ENOUGH TO PUT IT IN YET. WILL LET LATER SHIFTS MONITOR
AND ADD IF NECESSARY.
H85 WARM AIR ADVECTION INCREASES WEDNESDAY WITH MODELS DIFFERING
IN REGARDS TO THE AREAL COVERAGE OF PRECIPITATION ASSOCIATED WITH
IT. THE SREF GENERALLY SUPPORTS KEEPING THE PRIMARY PRECIPITATION
CHANCES CONFINED TO NORTHERN PARTS OF THE STATE THROUGH WEDNESDAY
AFTERNOON...WHILE THE DETERMINISTIC NAM/GFS/ECMWF BRING CHANCES
FARTHER SOUTH. HAVE EXPANDED SLIGHT CHANCE POPS SOUTHWARD TO
ACKNOWLEDGE THE DETERMINISTIC SOLUTIONS...WHICH ALSO LINES UP WITH
THE H85 WARM AIR ADVECTION. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH H85 TEMPERATURES RISING ABOVE ZERO DEGREES CELSIUS IN
THE SOUTHWEST. THE GOOD NEWS IS SURFACE TEMPERATURES ALSO WARM
ABOVE FREEZING IN THAT AREA...BUT IT WILL BE SOMETHING TO WATCH IN
REGARDS TO PRECIPITATION TYPE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
FOCUS IN THE LONG TERM IS ON THE LARGE SCALE UPPER LEVEL TROUGH
MOVING ACROSS THE CENTRAL CONUS THURSDAY INTO THE WEEKEND AND THE
COOLING TREND COMING THIS WEEKEND.
THE 12 UTC MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE LARGE SCALE
PATTERN...PROGRESSING A DEEP UPPER LEVEL TROUGH FROM THE ROCKIES
EARLY THURSDAY TO THE GREAT LAKES REGION SATURDAY. FOR THE NORTHERN
PLAINS THE 12 UTC MODEL GUIDANCE SHOWS THE MAJORITY OF PRECIPITATION
FALLING ACROSS SOUTHEASTERN MONTANA AS WELL AS NORTHERN AND WESTERN
SOUTH DAKOTA WEDNESDAY NIGHT THROUGH FRIDAY...WITH ONLY MINOR
ACCUMULATIONS ACROSS SOUTHERN NORTH DAKOTA. HOWEVER THE 12 UTC RUNS
OF THE NAM AND GEM-NHEM SHOW PRECIPITATION FALLING FURTHER NORTH
ALONG AND SOUTH OF THE I-94 CORRIDOR IN WESTERN AND CENTRAL NORTH
DAKOTA WEDNESDAY NIGHT THROUGH THURSDAY MORNING. WITH THAT SAID
THESE LATEST 12 UTC RUNS ARE OUTLIERS WITH PREVIOUS MODEL RUNS AND
THE CURRENT 12 UTC RUNS OF THE GFS AND ECMWF. WILL HAVE TO WATCH TO
SEE IF THE HEAVIER PRECIPITATION SOLUTIONS OF THE NAM AND GEM-NHEM
CONTINUE OVER THE NEXT FEW MODELS RUNS...AS THEY SUGGEST BETWEEN 2
AND 4 INCHES COULD FALL OVER THE PERIOD WHICH MAY PROMPT HEADLINES.
HOWEVER...AT THIS TIME WENT WITH A MODEL BLEND FOR THE FORECAST AND
THINKING ONLY AROUND AN INCH TO TWO OF SNOW IN THE SOUTHWEST WITH
GENERALLY LESS THAN AN INCH ELSEWHERE...WHICH DOES NOT REQUIRE ANY
HEADLINES.
PRECIPITATION TYPE WEDNESDAY NIGHT THROUGH FRIDAY APPEARS TO BE ALL
SNOW. MID LEVELS SHOULD BE MOIST ENOUGH FOR ICE CRYSTALS AND
TEMPERATURE PROFILES WILL BE BELOW FREEZING SO THAT NO MELTING
OCCURS. SOME FREEZING DRIZZLE IS POSSIBLE AT TIMES THURSDAY NIGHT AS
THE SYSTEM MOVES SOUTHEAST AND MID LEVELS DRY OUT...HOWEVER
ACCUMULATION WOULD BE MINOR AND ANY PERIOD OF FREEZING DRIZZLE WOULD
BE BRIEF. THUS ONLY MENTION OF SNOW IN THE GRIDS FOR NOW.
ARCTIC AIR WILL FILTER IN BEHIND THIS SYSTEM WITH HIGHS DROPPING
FROM THE 20S CHRISTMAS DAY TO THE SINGLE DIGITS NORTH ON FRIDAY AND
TEENS ELSEWHERE. WIND CHILLS SUNDAY NIGHT AND MONDAY NIGHT WILL BE
VERY COLD. CURRENT FORECAST HAS WIND CHILLS APPROACHING 25 BELOW
ZERO ACROSS THE NORTHERN HALF OF THE STATE EARLY MONDAY MORNING AND
DROPPING TO 25 BELOW ZERO TO 35 BELOW ZERO ACROSS MUCH OF THE STATE
MONDAY NIGHT INTO TUESDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 245 PM CST TUE DEC 23 2014
LIGHT SNOW CONTINUES TO DIMINISH ACROSS WESTERN AND CENTRAL NORTH
DAKOTA. A BRIEF PERIOD OF FLURRIES IS STILL POSSIBLE FROM MINOT TO
BISMARCK AND JAMESTOWN...BUT ANY IMPACTS SHOULD BE MINIMAL.
CEILINGS HAVE GENERALLY TRENDED TO MVFR...AND WENT WITH A FAIRLY
OPTIMISTIC OUTLOOK OVERNIGHT WITH SUGGESTIONS THAT THE MVFR MAY
LIFT TO VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CK
LONG TERM...MM
AVIATION...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1151 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 1151 PM CST MON DEC 22 2014
TEMPS IN THE CENTRAL RED RIVER VALLEY HAVE CONTINUE TO HOLD IN THE
34-36 DEGREE RANGE...BUT SOME SNOW IS STARTING TO MIX IN ACROSS
THE FARGO AREA. DRIZZLE REMAINS AT GFK AND BJI...WITH TEMPS STILL
ABOVE FREEZING. WILL CONTINUE TO KEEP A DRIZZLE CHANGING OVER TO
SNOW...WITH FREEZING DRIZZLE IN THE NORTHWEST WHERE TEMPS ARE
LOWER AND THE RAP SHOWS MORE DRYING IN THE -12 TO -18C DENDRITIC
GROWTH ZONE. WILL HOLD HEADLINES AS THEY ARE.
UPDATE ISSUED AT 1005 PM CST MON DEC 22 2014
SPOTTER REPORTS HAVE PRECIP IN DEVILS LAKE STARTING TO CHANGE OVER
TO SNOW. THERE HAVE BEEN SOME REPORTS OF SLICK ROADS IN EASTERN
WALSH AND PEMBINA COUNTIES EVEN THOUGH SFC TEMPS HAVE BEEN MAINLY
ABOVE FREEZING. HOWEVER...RADAR SHOWS PRECIP WILL MOVE FURTHER
WEST OUT OF THOSE AREAS AND INTO THE DEVILS LAKE BASIN. THINK THAT
THERE WILL BE SOME LINGERING FREEZING DRIZZLE CHANGING OVER TO
SNOW IN THE ADVISORY AREA...SO WILL KEEP THE HEADLINE GOING FOR A
BIT LONGER.
FURTHER SOUTH...THE AREAS AROUND FORMAN EASTWARD TO THE PARK
RAPIDS AREA HAVE TRANSITIONED OVER TO SNOW. SHORT TERM MODELS HAVE
THIS BAND HANGING AROUND A BIT LONGER THEN DISSIPATING AFTER
MIDNIGHT. THINK THAT AROUND A HALF AN INCH IS POSSIBLE...SO
ADJUSTED GRIDS OVER TO ALL SNOW. WILL KEEP AN EYE IN CASE THE SNOW
PERSISTS AND DROPS MORE THAN EXPECTED...BUT FOR NOW DO NOT THINK
AN ADVISORY IS NEEDED.
UPDATE ISSUED AT 703 PM CST MON DEC 22 2014
TWEAKED POPS AND PRECIP TYPE A BIT AS A BAND OF RAIN SHOWERS
CONTINUES TO SLOWLY MOVE ACROSS THE CWA. TEMPS HAVE BEEN STEADY OR
RISING IN THE DEVILS LAKE BASIN...BUT WITH SOME SPOTS STILL NEAR
THE FREEZING MARK AND SOME SPOTTY ICE ON ROADS BEING REPORTED BY
ND DOT...WILL KEEP THE ADVISORY GOING FOR RIGHT NOW. MODELS HAVE
TEMPS SLOWLY FALLING OFF THIS EVENING AND A SWITCH OVER TO SNOW
LATER ON OVERNIGHT. WILL KEEP THE HEADLINES AS THEY ARE AND WILL
TAKE A SECOND LOOK AT THE UPDATE IN A FEW HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CST MON DEC 22 2014
THE DENSE FOG ACROSS BARNES COUNTY HAS IMPROVED ACCORDING TO
WEB CAMS...AND WILL LET THAT ADVISORY EXPIRE AT 4PM.
ACROSS THE DEVILS LAKE BASIN (WINTER WEATHER ADVISORY UNTIL
12Z)...A FEW SITES STILL AT 32F...WITH OTHERS UP TO 34F. ROADS ARE
MOSTLY WET NOW...BUT IMAGINE SECONDARY ROADS ARE STILL ICY IN
AREAS WHERE TEMPERATURES REMAIN NEAR FREEZING. THERE REMAINS
DRIZZLE/FREEZING DRIZZLE AND AREAS OF DENSE FOG. ANTICIPATE
TEMPERATURES WILL FALL BELOW FREEZING THIS EVENING. FORCING (850MB
WARM AIR ADVECTION) WILL BE INCREASING INTO THIS AREA DURING THE
EVENING AS SEEN ON RADAR IMAGERY WITH STRONGER RETURNS FROM
COOPERSTOWN TO THIEF RIVER FALLS. NOT SURE OF THE PTYPE...WHICH
WILL BE DEPENDENT ON THE AIRMASS ALOFT (MOIST OR DRY?). IF ICE
NUCLEI CAN BE INTRODUCED EXPECT SNOW...IF NOT EXPECT FREEZING
DRIZZLE. LIKELY WILL BE A MIX...WHICH WILL CAUSE WIDESPREAD HAZARDOUS
TRAVEL CONDITIONS (AGAIN). NEXT SHIFTS WILL NEED TO MONITOR PTYPE
AND INCREASE/DECREASE SNOW AMOUNTS ACCORDINGLY (WILL GO AROUND AN
INCH FOR NOW...ANTICIPATE ALL SNOW BY TUESDAY MORNING). THERE HAVE
ALSO BEEN REPORTS OF ICE ACCRETION ON POWER LINES...SO IF MORE
FREEZING DRIZZLE/RAIN OCCURS THIS MAY BE AN ADDITIONAL HAZARD.
THERE WILL BE ANOTHER HEAVIER AREA OF PRECIP ASSOCIATED WITH THE
SFC LOW/INVERTED (SOUTHEAST NORTH DAKOTA) THIS EVENING. THE
RAIN/SNOW LINE LOOKS LIKE IT WILL SET UP JUST WEST OF THE FA...BUT
WILL NEED TO MONITOR.
TO THE EAST...LIKELY WILL BE SNOW MIXING IN WITH DRIZZLE BY TUESDAY
MORNING...JUST NOT SURE WHEN. FORCING IS MUCH WEAKER THAN TO THE
WEST...AND WARM AIR WILL LAST LONGER...AND ONLY EXPECT A DUSTING
OF SNOW (MAYBE UP TO AN INCH OR TWO DEPENDING ON TIMING OF
SWITCH-OVER TO SNOW AND IF/WHERE ANY STRONGER BANDS SET UP ON
TUESDAY).
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 PM CST MON DEC 22 2014
FOR TUESDAY NIGHT INTO THURSDAY...TEMPS WILL STAY MILD TUESDAY
NIGHT INTO CHRISTMAS DAY. UPPER RIDGE FLATTENS OUT INTO MORE OF A
ZONAL FLOW AS THE JET CORE PASSES ACROSS SRN CANADA. OTHERWISE...A
WEAK SFC LOW WILL CROSS JUST NORTH OF THE BORDER WITH A TRAILING
TROF CROSSING THE REGION. EXPECTING SOME LIGHT PCPN...MAINLY IN
THE NORTHERN PART OF THE AREA.
THURSDAY NIGHT THROUGH SUNDAY....UPPER TROF DIGGING IN OVER THE
INTERMOUNTAIN WEST...AND A VIGOROUS SHORTWAVE WILL INDUCE
CYCLOGENESIS AND DEVELOP AN AREA OF LOW PRESSURE THAT IS FORECAST TO
TRACK NE INTO IOWA AND WISCONSIN. MODELS PLACE THE BAROCLINIC ZONE
ON THE NW SIDE OF THE LOW ACROSS THE SE PORTION OF THE FORECAST
AREA...WITH ACCOMPANYING PCPN CHANCES. SOME QUESTION ON EXACT
PLACEMENT OF PCPN BAND ATTM...BUT LOOKING AT LEAST SOME MEASURABLE
PCPN ACROSS LAKES COUNTRY BACK TOWARD SE ND. COOLER AIR WILL FILTER
IN BEHIND THE LOW...BRINGING TEMPERATURES BACK DOWN CLOSER TO
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CST MON DEC 22 2014
IFR TO LIFR CONDITIONS CONTINUE AT MOST AREAS...WITH SOME PEAKS OF
MVFR AT TIMES. DRIZZLE AND LIGHT SNOW WILL REDUCE VIS TO AROUND
2-4SM AT TIMES...AND SOME 1SM IS POSSIBLE IN THE HEAVIER BANDS SO
INCLUDED THAT AT MOST TAF SITES TOWARDS MORNING. THINK THAT ANY
SNOW WILL BEGIN TO TAPER OFF MID DAY BUT WINDS WILL PICK UP OUT OF
THE NORTHWEST AT 15 KTS OR SO. CIGS WILL REMAIN IN THE 500-700 FT
RANGE AND THERE SHOULD STILL BE SOME MIST HANGING AROUND AND KEEPING
VIS DOWN IN THE 3-5SM RANGE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006-007-
014-015-024-026-028-054.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...HOPKINS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
104 PM EST TUE DEC 23 2014
.SYNOPSIS...
LOW PRESSURE OVER NORTHEASTERN IOWA WILL WEAKEN AS IT MOVES TO THE
NORTHEAST THROUGH THE AFTERNOON. A SECONDARY AREA OF LOW PRESSURE
WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID DEEPENING
AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT. THIS
SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH GUSTY
WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT THIS POINT HAVE ONLY MADE MINOR CHANGES TO THE GRIDS TO REFLECT
CURRENT CONDITIONS.
70 KNOT 5H JET IS NOSING INTO SOUTHERN OHIO WHICH SHOULD CONTINUE
TO PROVIDE SOME LIFT ACROSS THE SOUTHEASTERN THIRD OF THE COUNTY
WARNING AREA. HAVE EITHER SCATTERED OR LIKELY WORDING FOR THIS
REGION. STILL CANT RULE OUT A FEW SHOWERS ELSEWHERE SO KEPT A
CHANCE GOING.
PREVIOUS DISCUSSION...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST
CHANCE OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS
AFTERNOON ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF
SHOWERS WILL BE HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT
IT SEEMS REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE
MOVING UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL
BE IN THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
LOW PRESSURE LOCATED WEST OF CHICAGO WILL LIFT A WARM FRONT NORTH
ACROSS THE AREA TODAY WHICH IS CONTRIBUTING TO LOW CEILINGS AND
LOCALIZED RESTRICTIONS TO VISIBILITY. DOWNSLOPING WINDS AT CLE/ERI
WILL LIKELY KEEP CEILINGS IN THE MVFR RANGE WHILE OTHER SITES ARE
MOSTLY IFR. CAK/YNG MAY SEE CEILINGS LIFT FOR A FEW HOURS BEFORE
LOWERING AGAIN TONIGHT.
SCATTERED SHOWERS WILL INCREASE FROM THE SOUTH AFTER 22Z AND FILL
IN TONIGHT AS A STRONGER LOW PRESSURE SYSTEM TRACKS UP FROM THE
SOUTH. EXPECTING POOR AVIATION CONDITIONS WITH CEILINGS BELOW 500
FEET FOR MOST SITES EXCEPT ERI BY 09Z. EASTERN AREA MAY SEE A BREAK
IN THE RAIN DURING THE DAY ON WEDNESDAY. LEANED TOWARDS THE SLOWER
TRACK/TIMING OF THE NAM WHICH DOES NOT BRING THE REAL STRONG WINDS
ASSOCIATED WITH THE COLD FRONT INTO THE TAFS UNTIL CLOSER TO 00Z
SO DID NOT INCLUDE IN THE TERMINALS WITH THIS PACKAGE.
.OUTLOOK...STRONG SOUTHWEST WINDS GUSTING TO 40 KNOTS POSSIBLE
02-10Z THURS. NON VFR POSSIBLE THROUGH THURSDAY THEN AGAIN
SATURDAY AND SUNDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA/MULLEN
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...KEC
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1004 AM EST TUE DEC 23 2014
.SYNOPSIS...
LOW PRESSURE OVER NORTHEASTERN IOWA WILL WEAKEN AS IT MOVES TO THE
NORTHEAST THROUGH THE AFTERNOON. A SECONDARY AREA OF LOW PRESSURE
WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID DEEPENING
AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT. THIS
SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH GUSTY
WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT THIS POINT HAVE ONLY MADE MINOR CHANGES TO THE GRIDS TO REFLECT
CURRENT CONDITIONS.
70 KNOT 5H JET IS NOSING INTO SOUTHERN OHIO WHICH SHOULD CONTINUE
TO PROVIDE SOME LIFT ACROSS THE SOUTHEASTERN THIRD OF THE COUNTY
WARNING AREA. HAVE EITHER SCATTERED OR LIKELY WORDING FOR THIS
REGION. STILL CANT RULE OUT A FEW SHOWERS ELSEWHERE SO KEPT A
CHANCE GOING.
PREVIOUS DISCUSSION...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST
CHANCE OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS
AFTERNOON ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF
SHOWERS WILL BE HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT
IT SEEMS REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE
MOVING UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL
BE IN THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTING NORTH AT THIS TIME FORCING PRECIPITATION TO
MOVE NORTHEAST OF THE AREA AT THIS TIME. LITTLE TO NO
PRECIPITATION AT THIS TIME BEHIND THE FRONT AND NOT EXPECTING ANY
THING MORE THAN JUST SOME PATCHY DRIZZLE THROUGH MUCH OF THE DAY.
CEILINGS BEGIN TO LOWER FROM WEST TO EAST LATER IN THE DAY INTO
TONIGHT AS NEXT STORM SYSTEM APPROACHES FROM THE SOUTHWEST.
EXPECTING WINDS TO REMAIN LIGHT THROUGH THE DAY INTO TONIGHT OVER
MUCH OF THE AREA. HIGHEST WINDS WILL REMAIN CONFINED TO ERIE
PENNSYLVANIA NEAR THE LAKE.
.OUTLOOK...NON VFR POSSIBLE THROUGH THURSDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA/MULLEN
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
628 AM EST TUE DEC 23 2014
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE OVER THE NORTHERN PLAINS WILL LIFT A
WARM FRONT NORTH ACROSS THE AREA TODAY. A SECONDARY AREA OF LOW
PRESSURE WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID
DEEPENING AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT.
THIS SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH
GUSTY WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST CHANCE
OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS AFTERNOON
ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF SHOWERS WILL BE
HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT IT SEEMS
REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE MOVING
UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL BE IN
THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTING NORTH AT THIS TIME FORCING PRECIPITATION TO
MOVE NORTHEAST OF THE AREA AT THIS TIME. LITTLE TO NO
PRECIPITATION AT THIS TIME BEHIND THE FRONT AND NOT EXPECTING ANY
THING MORE THAN JUST SOME PATCHY DRIZZLE THROUGH MUCH OF THE DAY.
CEILINGS BEGIN TO LOWER FROM WEST TO EAST LATER IN THE DAY INTO
TONIGHT AS NEXT STORM SYSTEM APPROACHES FROM THE SOUTHWEST.
EXPECTING WINDS TO REMAIN LIGHT THROUGH THE DAY INTO TONIGHT OVER
MUCH OF THE AREA. HIGHEST WINDS WILL REMAIN CONFINED TO ERIE
PENNSYLVANIA NEAR THE LAKE.
.OUTLOOK...NON VFR POSSIBLE THROUGH THURSDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS NORMAN OK
1132 PM CST MON DEC 22 2014
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH 24/00Z... BUT THEN MVFR CIGS
ARE EXPECTED TO RETURN TO MANY AREAS AFTER 24/00Z. NORTHWEST WINDS
WILL INCREASE AND BECOME GUSTY AFTER SUNRISE TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1021 PM CST MON DEC 22 2014/
UPDATE...
INCREASED RAIN CHANCES FOR THE REST OF TONIGHT ACROSS WESTERN
NORTH TEXAS...SOUTH OF A CROWELL TO WICHITA FALLS LINE.
DISCUSSION...
BASED ON LATEST RADAR AND THE KNOX CITY WEST TEXAS MESONET
REPORTING 0.06 INCHES OF RAINFALL IN THE PAST HOUR...INCREASED
RAIN CHANCES IN THE LOCATIONS MENTIONED ABOVE...INCLUDING
THE SEYMOUR...ARCHER CITY...AND KNOX CITY AREAS. LIGHT RAIN
MAY AFFECT PARTS OF FAR SOUTHERN OKLAHOMA...SOUTH OF A WALTERS
TO COALGATE LINE LATER TONIGHT. ANY RAINFALL IS EXPECTED TO
REMAIN LIGHT...GENERALLY 0.01 TO 0.25 INCHES WITH THE HIGHEST
AMOUNTS IN THE LOCATIONS MENTIONED ABOVE.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 641 PM CST MON DEC 22 2014/
UPDATE...
INCREASED CLOUD COVER TONIGHT AND DELAYED RAIN CHANCES A FEW
HOURS IN WESTERN NORTH TEXAS.
DISCUSSION...
LIGHT RAIN MAY IMPACT LOCATIONS SOUTH OF THE RED RIVER
TONIGHT...MAINLY AFTER MIDNIGHT.
BASED ON LATEST SATELLITE AND HRRR MODEL OUTPUT...INCREASED
CLOUD COVER TONIGHT ACROSS THE AREA...ESPECIALLY SOUTH OF I-40.
LATEST RADARS INDICATED LIGHT PRECIPITATION OVER THE TEXAS HIGH
PLAINS TO OUR WEST...SOME OF WHICH WAS NOT REACHING THE GROUND
DUE TO DRY LOW LEVELS. THINK SOME OF THIS PRECIPITATION WILL REACH
THE GROUND ONCE IT ENTERS WESTERN NORTH TEXAS IN THE NEXT FEW
HOURS...BUT FOR THE MOST PART...MEASURABLE PRECIPITATION...0.01
INCH OF RAINFALL OR GREATER...IS EXPECTED TO OCCUR AFTER MIDNIGHT.
MODEL PROFILES SUPPORT ALL LIQUID AT THE GROUND WITH THIS
PRECIPITATION WITH WET BULB ZERO HEIGHTS ABOVE 1500 FT AGL.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 539 PM CST MON DEC 22 2014/
AVIATION...
MOSTLY VFR CONDITIONS IN THE 00Z TAFS... FINALLY. AN EXCEPTION MAY
BE OVER FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TUESDAY
MORNING AS SOME MVFR VSBY/CIGS WILL BE POSSIBLE... MOST LIKELY AT
KSPS. THE HIGHEST CHANCES OF PRECIPITATION WILL BE SOUTH OF OUR
TAF SITES.
PREV DISCUSSION... /ISSUED 303 PM CST MON DEC 22 2014/
DISCUSSION...
A FEW WEAK ECHOES ARE SHOWING UP ON AREA RADARS. MEASURABLE
PRECIPITATION IS NOT EXPECTED THROUGH EARLY EVENING...ALTHOUGH A
FEW SMALL PATCHES OF DRIZZLE OR SPRINKLES CANNOT BE RULED OUT.
AN AREA OF MOISTURE AND ISENTROPIC LIFT WILL ACCOMPANY A MID-LEVEL
WAVE ACROSS OUR TEXAS AND FAR SOUTHERN OKLAHOMA COUNTIES
OVERNIGHT AND EARLY TUESDAY. THERE WILL BE A TIGHT GRADIENT OF
RAIN CHANCES ALONG THE NORTHERN EDGE. TEMPERATURES WILL BE WARM
ENOUGH FOR ALL RAIN...EXCEPT POSSIBLY ALONG THE NORTHERN
FRINGE...WHERE A MIX OF RAIN/SNOW MAY OCCUR EARLY TOMORROW
MORNING.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ANOTHER GLOB OF MOISTURE
IS FORECAST TO FOLLOW BEHIND THE DEPARTING STORM SYSTEM. THIS
WILL BRING A CHANCE OF LIGHT SNOW TO NORTHERN OKLAHOMA. MINIMAL
LIFT IS EXPECTED IN THIS PART OF THE STORM SYSTEM...SO ONLY VERY
LIGHT ACCUMULATION IS EXPECTED IN THE NORTHWEST. A MIX OF LIGHT
RAIN AND SNOW MAY EXTEND AS FAR SOUTH AS CENTRAL OKLAHOMA.
STRONG NORTHWEST WINDS ARE EXPECTED TOMORROW...ENHANCED BY COLD
AIR ADVECTION. A WIND ADVISORY MAY BE NEEDED TOMORROW...DEPENDING
ON THE WIND GUIDANCE TRENDS.
CHRISTMAS DAY WILL BE WINDY...WARM...AND DRY. IF CURRENT MODEL
GUIDANCE IS ANYWHERE CLOSE TO CORRECT...A WIND ADVISORY WILL BE
NECESSARY...AND A HIGH WIND WATCH/WARNING MAY NEED TO BE
CONSIDERED. MOST MODELS SHOW 30-50 KT WINDS BETWEEN 850 MB AND THE
LOWEST LAYER ABOVE THE SURFACE.
A COLD FRONT WILL ARRIVE FRIDAY...BRINGING A NOTICEABLE DROP IN
TEMPERATURES. THE WEEKEND IS CURRENTLY BEYOND THE RANGE OF
COHERENT MODEL FORECASTS. THEY DIVERGE QUITE SERIOUSLY AROUND
SATURDAY...SO THE WEEKEND FORECAST IS CURRENTLY A MIX OF GUIDANCE
WITH LOW CONFIDENCE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 48 33 43 / 0 10 20 10
HOBART OK 36 48 31 46 / 10 10 10 0
WICHITA FALLS TX 40 51 34 48 / 20 20 10 0
GAGE OK 32 42 28 45 / 0 20 20 0
PONCA CITY OK 34 46 33 41 / 0 10 20 10
DURANT OK 42 51 36 45 / 20 50 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
99/99/01
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1021 PM CST MON DEC 22 2014
.UPDATE...
INCREASED RAIN CHANCES FOR THE REST OF TONIGHT ACROSS WESTERN
NORTH TEXAS...SOUTH OF A CROWELL TO WICHITA FALLS LINE.
&&
.DISCUSSION...
BASED ON LATEST RADAR AND THE KNOX CITY WEST TEXAS MESONET
REPORTING 0.06 INCHES OF RAINFALL IN THE PAST HOUR...INCREASED
RAIN CHANCES IN THE LOCATIONS MENTIONED ABOVE...INCLUDING
THE SEYMOUR...ARCHER CITY...AND KNOX CITY AREAS. LIGHT RAIN
MAY AFFECT PARTS OF FAR SOUTHERN OKLAHOMA...SOUTH OF A WALTERS
TO COALGATE LINE LATER TONIGHT. ANY RAINFALL IS EXPECTED TO
REMAIN LIGHT...GENERALLY 0.01 TO 0.25 INCHES WITH THE HIGHEST
AMOUNTS IN THE LOCATIONS MENTIONED ABOVE.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 641 PM CST MON DEC 22 2014/
UPDATE...
INCREASED CLOUD COVER TONIGHT AND DELAYED RAIN CHANCES A FEW
HOURS IN WESTERN NORTH TEXAS.
DISCUSSION...
LIGHT RAIN MAY IMPACT LOCATIONS SOUTH OF THE RED RIVER
TONIGHT...MAINLY AFTER MIDNIGHT.
BASED ON LATEST SATELLITE AND HRRR MODEL OUTPUT...INCREASED
CLOUD COVER TONIGHT ACROSS THE AREA...ESPECIALLY SOUTH OF I-40.
LATEST RADARS INDICATED LIGHT PRECIPITATION OVER THE TEXAS HIGH
PLAINS TO OUR WEST...SOME OF WHICH WAS NOT REACHING THE GROUND
DUE TO DRY LOW LEVELS. THINK SOME OF THIS PRECIPITATION WILL REACH
THE GROUND ONCE IT ENTERS WESTERN NORTH TEXAS IN THE NEXT FEW
HOURS...BUT FOR THE MOST PART...MEASURABLE PRECIPITATION...0.01
INCH OF RAINFALL OR GREATER...IS EXPECTED TO OCCUR AFTER MIDNIGHT.
MODEL PROFILES SUPPORT ALL LIQUID AT THE GROUND WITH THIS
PRECIPITATION WITH WET BULB ZERO HEIGHTS ABOVE 1500 FT AGL.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 539 PM CST MON DEC 22 2014/
AVIATION...
MOSTLY VFR CONDITIONS IN THE 00Z TAFS... FINALLY. AN EXCEPTION MAY
BE OVER FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TUESDAY
MORNING AS SOME MVFR VSBY/CIGS WILL BE POSSIBLE... MOST LIKELY AT
KSPS. THE HIGHEST CHANCES OF PRECIPITATION WILL BE SOUTH OF OUR
TAF SITES.
PREV DISCUSSION... /ISSUED 303 PM CST MON DEC 22 2014/
DISCUSSION...
A FEW WEAK ECHOES ARE SHOWING UP ON AREA RADARS. MEASURABLE
PRECIPITATION IS NOT EXPECTED THROUGH EARLY EVENING...ALTHOUGH A
FEW SMALL PATCHES OF DRIZZLE OR SPRINKLES CANNOT BE RULED OUT.
AN AREA OF MOISTURE AND ISENTROPIC LIFT WILL ACCOMPANY A MID-LEVEL
WAVE ACROSS OUR TEXAS AND FAR SOUTHERN OKLAHOMA COUNTIES
OVERNIGHT AND EARLY TUESDAY. THERE WILL BE A TIGHT GRADIENT OF
RAIN CHANCES ALONG THE NORTHERN EDGE. TEMPERATURES WILL BE WARM
ENOUGH FOR ALL RAIN...EXCEPT POSSIBLY ALONG THE NORTHERN
FRINGE...WHERE A MIX OF RAIN/SNOW MAY OCCUR EARLY TOMORROW
MORNING.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ANOTHER GLOB OF MOISTURE
IS FORECAST TO FOLLOW BEHIND THE DEPARTING STORM SYSTEM. THIS
WILL BRING A CHANCE OF LIGHT SNOW TO NORTHERN OKLAHOMA. MINIMAL
LIFT IS EXPECTED IN THIS PART OF THE STORM SYSTEM...SO ONLY VERY
LIGHT ACCUMULATION IS EXPECTED IN THE NORTHWEST. A MIX OF LIGHT
RAIN AND SNOW MAY EXTEND AS FAR SOUTH AS CENTRAL OKLAHOMA.
STRONG NORTHWEST WINDS ARE EXPECTED TOMORROW...ENHANCED BY COLD
AIR ADVECTION. A WIND ADVISORY MAY BE NEEDED TOMORROW...DEPENDING
ON THE WIND GUIDANCE TRENDS.
CHRISTMAS DAY WILL BE WINDY...WARM...AND DRY. IF CURRENT MODEL
GUIDANCE IS ANYWHERE CLOSE TO CORRECT...A WIND ADVISORY WILL BE
NECESSARY...AND A HIGH WIND WATCH/WARNING MAY NEED TO BE
CONSIDERED. MOST MODELS SHOW 30-50 KT WINDS BETWEEN 850 MB AND THE
LOWEST LAYER ABOVE THE SURFACE.
A COLD FRONT WILL ARRIVE FRIDAY...BRINGING A NOTICEABLE DROP IN
TEMPERATURES. THE WEEKEND IS CURRENTLY BEYOND THE RANGE OF
COHERENT MODEL FORECASTS. THEY DIVERGE QUITE SERIOUSLY AROUND
SATURDAY...SO THE WEEKEND FORECAST IS CURRENTLY A MIX OF GUIDANCE
WITH LOW CONFIDENCE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 48 33 43 / 10 10 20 10
HOBART OK 36 48 31 46 / 10 10 10 0
WICHITA FALLS TX 40 51 34 48 / 20 20 10 0
GAGE OK 32 42 28 45 / 10 20 20 0
PONCA CITY OK 34 46 33 41 / 10 10 20 10
DURANT OK 42 51 36 45 / 20 50 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 PM EST WED DEC 24 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM WILL MOVE UP THROUGH THE EASTERN
GREAT LAKES THIS EVENING...DRAGGING A COLD FRONT THROUGH THE
REGION OVERNIGHT. GUSTY WEST WINDS WILL DEVELOP BEHIND THE FRONT
LATE TONIGHT AND THURSDAY. ANOTHER LESS POTENT COLD FRONT WILL
MOVE ACROSS THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EARLIER RAIN HAS SHIFTED EAST OF THE AREA WITH AXIS OF LL JET AND
PLUME OF HIGHEST PWATS. LOOP OF SATL-DERIVED PWATS SHOW THIS
ATMOSPHERIC RIVER...WITH ORIGINS OVR THE GULF OF MEX...PUSHING JUST
OFF THE E COAST AS OF 00Z. FOCUS IS NOW ON SHARP COLD FRONT
APPROACHING FROM THE WEST. WATER VAPOR LOOP SHOWS UPPER LVL
SHORTWAVE LIFTING NE THRU LOWER MICHIGAN EARLY THIS EVENING.
GIVEN THIS TRAJECTORY...EXPECT BULK LG SCALE FORCING TO PASS NORTH
OF PA. THUS...SVR WX THREAT FROM APPROACHING SQUALL LINE SHOULD BE
LIMITED TO THE NW MTNS...WHERE COMBINATION OF SOME MEAGER CAPE AND
STRONG FORCING IS EXPECTED. LATEST HRRR OUTPUT SUGGEST THE THREAT
WINDOW WILL BE BTWN 02Z- 04Z ACROSS THE NW COUNTIES.
A MORE STABLE AIR MASS ACROSS THE REST OF CENTRAL PA WILL LIKELY
PRECLUDE SVR WX. HOWEVER...COLD FRONT WILL BE ACCOMPANIED BY
SHOWERS OVR MOST OF THE AREA LATER TONIGHT. HAVE PLACED THE
HIGHEST POPS ACROSS THE SUSQ VALLEY...WHERE POSITIVE PWAT
ANOMALIES THE HIGHEST. IT WILL BE AN UNSEASONABLY MILD CHRISTMAS
EVE...AS THE REGION REMAINS WITHIN DEEP SOUTHERLY FLOW AHEAD OF
GRT LKS LOW PRES SYSTEM. AREAS OF DRIZZLE AND FOG WILL PRECEDE THE
ARRIVAL OF THE FRONTAL SHOWERS...WHICH SHOULD ARRIVE OVR THE SUSQ
VALLEY JUST AFTER MIDNIGHT.
THE COLD FRONT SHOULD BE ENTERING THE ALLEGHENY PLATEAU ARND
02Z-03Z AND EXITING THE SUSQ VALLEY DURING THE PRE-DAWN HOURS.
BEST CHC OF THUNDER WILL BE ACROSS THE NW MTNS CLOSEST TO PATH OF
MID LVL SHORTWAVE. HOWEVER...CAN/T COMPLETELY RULE OUT A RUMBLE
FURTHER SE WITH FROPA. ALTHOUGH THE GREATEST THREAT OF SVR WX WILL
BE ACROSS THE NW MTNS...SOME FAIRLY STRONG GUSTS WILL MIX TO THE
SFC IMMEDIATELY FOLLOWING FRONTAL PASSAGE OVERNIGHT. LATEST BUFKIT
SOUNDINGS SUPPORT GUSTS TO BTWN 40-45KTS OVR THE ALLEGHENY
PLATEAU...WITH SLIGHTLY LOWER GUST POTENTIAL FURTHER EAST.
STEADY OR SLOWLY RISING TEMPS EXPECTED OVERNIGHT UNTIL FRONT
ARRIVES. BY DAWN...THE FRONT WILL HAVE CLEARED THE ENTIRE STATE
AND TEMPS SHOULD RANGE FROM THE M30S OVR THE ALLEGHENY MTNS...TO
THE M40S ACROSS THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
CHRISTMAS DAY WILL BRING A TRANSITION INTO A PRETTY TYPICAL POST
FRONTAL COOL SEASON PATTERN...WITH CLOUDS AND BLUSTERY GUSTY
WESTERLY WINDS. HIGHER ELEVATIONS WILL LIKELY SEE GUSTS AS HIGH
AS 40-45 MPH...WHILE BUKFIT DATA IMPLIES TOP WGUSTS IN THE
35-40MPH RANGE FOR THE REST OF US.
THE AIR MASS WILL BE FAR FROM COLD FOR LATE DECEMBER
STANDARDS...BUT COLD ENOUGH TO SUPPORT SCT OROGRAPHIC SNOW SHOWERS
OVR THE ALLEGHENY PLATEAU...WITH THE CENTRAL RIDGE-VALLEY REGION
SEEING LITTLE MORE THAN A PASSING LIGHT RAIN OR SNOW SHOWER. WITH
SFC TEMPS EXPECTED TO BE ABV FREEZING EVERYWHERE AND SNOW SHOWERS
LIGHT...EXPECT NO ACCUMULATION EXCEPT PERHAPS A DUSTING OVR THE
HIGHEST RIDGETOPS.
ENS MEAN 925/850 TEMPS SUPPORT HIGH TEMPS CHRISTMAS DAY FROM THE
M30S OVR THE ALLEGHENY MTNS...TO NR 50F ACROSS THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
POTENT LONGWAVE UPPER TROF EXITING THE EAST COAST AT THE START OF
THE PERIOD WILL BE REPLACED BY UPPER RIDGING INTO THE WEEKEND. AS
LONGWAVE UPPER TROFFING IS FORECAST TO DEVELOP OVER THE WRN US
STARTING EARLY IN THE PD AND NRN STREAM ENERGY RETREATS INTO
EASTERN CANADA...MDT TO STRONG SWRLY FLOW ALOFT IS THEN FORECAST
TO DOMINATE THE EASTERN CONUS FROM LATE IN THE WEEKEND THROUGH THE
REMAINDER OF THE YEAR.
MEDIUM RANGE GUIDANCE IS FAIRLY CONSISTENT ESPECIALLY EARLY IN
THE PERIOD...BUT THEN SOME DIFFERENCES ARISE IN 500MB FLOW
PATTERN AFTER MONDAY AS THE ECMWF MOVES ENERGY EAST FASTER...WHILE
THE GFS CLOSES OFF AN UPPER LOW OVER THE DESERT SW.
A NORTHERN STREAM WAVE IS FORECAST TO SUPPORT A COLD FRONT MOVING
EAST ACROSS THE STATE LATE IN THE WEEKEND...POSSIBLY STALLING
NEAR THE MASON DIXON LINE INTO MONDAY AS IT ENCOUNTERS RESISTANCE
FROM THE BUILDING UPPER FLOW. THIS FRONT LOOKS TO BE THE MAIN
FOCUS FOR PCPN IN THE LONG TERM PERIOD. WITH SNOW TO THE NORTH AND
WEST...AND A MIX TO RAIN ACROSS THE SOUTH.
WITH RIDGING OR SWRLY FLOW ALOFT MUCH OF THE PERIOD WILL FEATURE
ABOVE NORMAL TEMPS...WITH A COOL DOWN TOWARD NORMAL BY NEW YEARS
EVE.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
THE MAIN CONCERNS REMAINS LIFR TO MVFR CONDITIONS AND LLWS
THIS EVENING FOR MUCH OF THE AREA.
STILL WATCHING LINE OF STORMS ALONG THE PA...OH BORDER. SINCE
WE ARE AT LEAST 10 DEGREES COOLER AND DEWPOINTS LOWER...THINK ANY
REAL STRONG STORMS WILL WEAKEN AS THEY MOVE TOWARD CENTRAL PA.
WILL CONTINUE TO MONITOR. SOME OF THE STRONGER STORMS WILL
TRACK ACROSS NW WARREN COUNTY...JUST WEST OF BFD.
HOWEVER...EXPECT SOME GUSTY WINDS WITH THE COLD FRONT AND
JUST BEHIND THE FRONT. WINDS WILL SLOWLY DIE DOWN DURING THE
DAY ON THU.
LOW CIGS WILL PERSIST THE FIRST PART OF CRHISTMAS ACROSS THE
AREA. EXPECT CONDITIONS TO BECOME VFR LATER IN THE DAY.
NOT LOOKING BAD INTO FRIDAY AND SAT.
OUTLOOK...
FRI...MAINLY VFR.
SAT...VFR.
SUN-MON...MVFR TO IFR WITH SCATTERED RAIN AND SNOW SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON EST THURSDAY FOR PAZ004>006-010>012-
017-018-024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
747 PM EST WED DEC 24 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM WILL MOVE UP THROUGH THE EASTERN
GREAT LAKES THIS EVENING...DRAGGING A COLD FRONT THROUGH THE
REGION OVERNIGHT. GUSTY WEST WINDS WILL DEVELOP BEHIND THE FRONT
LATE TONIGHT AND THURSDAY. ANOTHER LESS POTENT COLD FRONT WILL
MOVE ACROSS THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EARLIER RAIN HAS SHIFTED EAST OF THE AREA WITH AXIS OF LL JET AND
PLUME OF HIGHEST PWATS. LOOP OF SATL-DERIVED PWATS SHOW THIS
ATMOSPHERIC RIVER...WITH ORIGINS OVR THE GULF OF MEX...PUSHING JUST
OFF THE E COAST AS OF 00Z. FOCUS IS NOW ON SHARP COLD FRONT
APPROACHING FROM THE WEST. WATER VAPOR LOOP SHOWS UPPER LVL
SHORTWAVE LIFTING NE THRU LOWER MICHIGAN EARLY THIS EVENING.
GIVEN THIS TRAJECTORY...EXPECT BULK LG SCALE FORCING TO PASS NORTH
OF PA. THUS...SVR WX THREAT FROM APPROACHING SQUALL LINE SHOULD BE
LIMITED TO THE NW MTNS...WHERE COMBINATION OF SOME MEAGER CAPE AND
STRONG FORCING IS EXPECTED. LATEST HRRR OUTPUT SUGGEST THE THREAT
WINDOW WILL BE BTWN 02Z- 04Z ACROSS THE NW COUNTIES.
A MORE STABLE AIR MASS ACROSS THE REST OF CENTRAL PA WILL LIKELY
PRECLUDE SVR WX. HOWEVER...COLD FRONT WILL BE ACCOMPANIED BY
SHOWERS OVR MOST OF THE AREA LATER TONIGHT. HAVE PLACED THE
HIGHEST POPS ACROSS THE SUSQ VALLEY...WHERE POSITIVE PWAT
ANOMALIES THE HIGHEST. IT WILL BE AN UNSEASONABLY MILD CHRISTMAS
EVE...AS THE REGION REMAINS WITHIN DEEP SOUTHERLY FLOW AHEAD OF
GRT LKS LOW PRES SYSTEM. AREAS OF DRIZZLE AND FOG WILL PRECEDE THE
ARRIVAL OF THE FRONTAL SHOWERS...WHICH SHOULD ARRIVE OVR THE SUSQ
VALLEY JUST AFTER MIDNIGHT.
THE COLD FRONT SHOULD BE ENTERING THE ALLEGHENY PLATEAU ARND
02Z-03Z AND EXITING THE SUSQ VALLEY DURING THE PRE-DAWN HOURS.
BEST CHC OF THUNDER WILL BE ACROSS THE NW MTNS CLOSEST TO PATH OF
MID LVL SHORTWAVE. HOWEVER...CAN/T COMPLETELY RULE OUT A RUMBLE
FURTHER SE WITH FROPA. ALTHOUGH THE GREATEST THREAT OF SVR WX WILL
BE ACROSS THE NW MTNS...SOME FAIRLY STRONG GUSTS WILL MIX TO THE
SFC IMMEDIATELY FOLLOWING FRONTAL PASSAGE OVERNIGHT. LATEST BUFKIT
SOUNDINGS SUPPORT GUSTS TO BTWN 40-45KTS OVR THE ALLEGHENY
PLATEAU...WITH SLIGHTLY LOWER GUST POTENTIAL FURTHER EAST.
STEADY OR SLOWLY RISING TEMPS EXPECTED OVERNIGHT UNTIL FRONT
ARRIVES. BY DAWN...THE FRONT WILL HAVE CLEARED THE ENTIRE STATE
AND TEMPS SHOULD RANGE FROM THE M30S OVR THE ALLEGHENY MTNS...TO
THE M40S ACROSS THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
CHRISTMAS DAY WILL BRING A TRANSITION INTO A PRETTY TYPICAL POST
FRONTAL COOL SEASON PATTERN...WITH CLOUDS AND BLUSTERY GUSTY
WESTERLY WINDS. HIGHER ELEVATIONS WILL LIKELY SEE GUSTS AS HIGH
AS 40-45 MPH...WHILE BUKFIT DATA IMPLIES TOP WGUSTS IN THE
35-40MPH RANGE FOR THE REST OF US.
THE AIR MASS WILL BE FAR FROM COLD FOR LATE DECEMBER
STANDARDS...BUT COLD ENOUGH TO SUPPORT SCT OROGRAPHIC SNOW SHOWERS
OVR THE ALLEGHENY PLATEAU...WITH THE CENTRAL RIDGE-VALLEY REGION
SEEING LITTLE MORE THAN A PASSING LIGHT RAIN OR SNOW SHOWER. WITH
SFC TEMPS EXPECTED TO BE ABV FREEZING EVERYWHERE AND SNOW SHOWERS
LIGHT...EXPECT NO ACCUMULATION EXCEPT PERHAPS A DUSTING OVR THE
HIGHEST RIDGETOPS.
ENS MEAN 925/850 TEMPS SUPPORT HIGH TEMPS CHRISTMAS DAY FROM THE
M30S OVR THE ALLEGHENY MTNS...TO NR 50F ACROSS THE LOWER SUSQ
VALLEY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
POTENT LONGWAVE UPPER TROF EXITING THE EAST COAST AT THE START OF
THE PERIOD WILL BE REPLACED BY UPPER RIDGING INTO THE WEEKEND. AS
LONGWAVE UPPER TROFFING IS FORECAST TO DEVELOP OVER THE WRN US
STARTING EARLY IN THE PD AND NRN STREAM ENERGY RETREATS INTO
EASTERN CANADA...MDT TO STRONG SWRLY FLOW ALOFT IS THEN FORECAST
TO DOMINATE THE EASTERN CONUS FROM LATE IN THE WEEKEND THROUGH THE
REMAINDER OF THE YEAR.
MEDIUM RANGE GUIDANCE IS FAIRLY CONSISTENT ESPECIALLY EARLY IN
THE PERIOD...BUT THEN SOME DIFFERENCES ARISE IN 500MB FLOW
PATTERN AFTER MONDAY AS THE ECMWF MOVES ENERGY EAST FASTER...WHILE
THE GFS CLOSES OFF AN UPPER LOW OVER THE DESERT SW.
A NORTHERN STREAM WAVE IS FORECAST TO SUPPORT A COLD FRONT MOVING
EAST ACROSS THE STATE LATE IN THE WEEKEND...POSSIBLY STALLING
NEAR THE MASON DIXON LINE INTO MONDAY AS IT ENCOUNTERS RESISTANCE
FROM THE BUILDING UPPER FLOW. THIS FRONT LOOKS TO BE THE MAIN
FOCUS FOR PCPN IN THE LONG TERM PERIOD. WITH SNOW TO THE NORTH AND
WEST...AND A MIX TO RAIN ACROSS THE SOUTH.
WITH RIDGING OR SWRLY FLOW ALOFT MUCH OF THE PERIOD WILL FEATURE
ABOVE NORMAL TEMPS...WITH A COOL DOWN TOWARD NORMAL BY NEW YEARS
EVE.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
THE MAIN CONCERNS REMAIN LIFR TO MVFR CONDITIONS AND LLWS
THIS EVENING.
HOWEVER...WATCHING LINE OF STORMS WEST OF PA. SINCE WE ARE
AT LEAST 10 DEGREES COOLER AND DEWPOINTS LOWER...THINK ANY
REAL STRONG STORMS WILL WEAKEN AS THEY MOVE TOWARD CENTRAL
PA. WILL CONTINUE TO MONITOR.
21Z TAFS SENT.
EARLIER DISCUSSION BELOW.
WIDESPREAD MVFR/IFR WITH RAIN AND AREAS OF FOG WILL CONTINUE
INTO THE EVENING AS A STORM SYSTEM MOVES INTO THE EASTERN GREAT
LAKES THIS EVENING.
THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL
PENNSYLVANIA TONIGHT. ISOLATED EMBEDDED THUNDERSTORMS CANNOT BE
RULED OUT ALONG THE FRONT. STRONG AND GUSTY WEST WINDS WILL
DEVELOP BEHIND THE FRONT TONIGHT AND THURSDAY.
INCLUDED LLWS FOR ALL TAF SITES AS WINDS ALOFT BEGIN TO INCREASE
AHEAD OF THE APPROACHING FRONTAL SYSTEM WHILE SFC WINDS REMAIN
RELATIVELY LIGHT OUT OF THE SE.
WESTERN HIGH TERRAIN TERMINALS WILL HOLD ONTO REDUCED CONDITIONS
THROUGH MUCH OF CHRISTMAS DAY AFTER WINDS SHIFT TO THE WEST
BEHIND THE COLD FRONT...WHILE CENTRAL AND EASTERN TERMINALS WILL
SEE CEILINGS IMPROVE TO THE 3000-5000` RANGE BY LATE TONIGHT OR
FAIRLY EARLY CHRISTMAS MORNING.
OUTLOOK...
FRI...FAIR AND MOSTLY VFR.
SAT...VFR.
SUN...MVFR TO IFR WITH SCATTERED RAIN SHOWERS.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON EST THURSDAY FOR PAZ004>006-010>012-
017-018-024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
215 AM EST TUE DEC 23 2014
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE DELMARVA PENINSULA WILL
DRIFT SLOWLY TO THE NORTHEAST THIS MORNING. AN INTENSIFYING STORM
SYSTEM WILL TRACK WEST AND NORTH OF PENNSYLVANIA WEDNESDAY
NIGHT...PUSHING A COLD FRONT THROUGH THE STATE ON CHRISTMAS EVE.
ANOTHER LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE REGION BY
NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
PERSISTENT...AND RATHER DEEP SOUTH-SWRLY ISENTROPIC LIFT IN THE
295-305 K THETA LAYER /ATOP A LIGHT EASTERLY FLOW AT THE SFC/ WILL
BE FOCUSED ACRS CENTRAL AND NERN PENN EARLY TODAY.
PERIODS OF LIGHT RAIN...FZRA...AND DRIZZLE WILL OCCUR THROUGH THE
MID MORNING...AND WITH TEMPS TEETERING ON THE 32F MARK THROUGHOUT
MUCH OF THE CENTRAL AND NRN MTNS...WILL MAINTAIN FZRA ADVISORY
THROUGH 09Z. OUTSIDE OF THE ADVISORY AREA...TEMPS WERE MAINLY
IN THE 33-36F RANGE WITH JUST SOME SPOTTY LIGHT RAIN...DRIZZLE AND
PATCHY -FZRA/FZDZ. A FEW LOCATIONS COULD SEE UP TO ONE TENTH OF AN
INCH ICE ACCUM...BUT MOST PLACES WILL SEE LESS. STILL...UNTREATED
ROADS AND WALKWAYS WILL BE TREACHEROUS IN SPOTS.
LATEST RAP MAY BE A FEW HOURS TOO FAST WARMING UP TEMPS
SUFFICIENTLYABOVE THE 32 DEG MARK DURING THE PREDAWN HOURS
TODAY...SO WE MAY OPT TO EXTEND THE ADVISORY THROUGH 13Z.
AFTERWARD...TEMPS CLIMBING INTO THE UPPER 30S TO MID 40S WILL BE
ACCOMPANIED BY DECREASING AREAS OF LIGHT RAIN/SHOWERS OR DRIZZLE
WITH QPF AOB 0.10 OF AN INCH.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
LOOKING AT MAINLY A CLOUDY LATE MORNING AND AFTERNOON TODAY
WITH SOME PATCHY LIGHT RAIN OR DRIZZLE. TEMPERATURES WILL BE
ABOVE NORMAL...BUT MAINLY IN THE 40S...AS THE MAIN LOW IS TOO FAR
WEST FOR CENTRAL PA TO BE IN MUCH OF A SOUTHERLY GRADIENT.
A BETTER CHANCE OF RAIN ARRIVES LATER TONIGHT INTO WED...AS COLD
FRONT MOVES TO THE EAST.
TEMPERATURES WILL CLIMB INTO THE 50S WED AFTERNOON INTO WED
NIGHT...AS STRONGER SOUTHERLY WINDS DEVELOP.
WENT WITH A CHANCE OF THUNDER WED EVENING...GIVEN DEWPOINTS
IN THE UPPER 40S TO LOWER 50S. ALSO FAIRLY STRONG DYNAMICS
AND WIND FIELDS. LIMITING FACTOR FOR SEVERE STORMS WILL BE
TIME OF DAY AND THERMAL RIDGE WELL TO THE EAST OF THE FRONT.
WIND GUST COULD BE IN THE ADVISORY RANGE LATE.
DID NOT BUY INTO THE NAM SOLUTION AT THIS POINT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
CLOUDS SHOULD BREAK BEHIND THE COLD FRONT ON THU. A FEW SNOW
AND RAIN SHOWERS WILL BE POSSIBLE WITH THE UPPER LEVEL TROUGH.
MUCH OF THE DAY WILL BE DRY. NOT REAL COLD BEHIND THE FRONT.
SW FLOW ON FRIDAY WILL BRING IN MILD AIR.
A FEW MORE SHOWERS LATE FRIDAY INTO SUNDAY...AS THE NEXT COLD
FRONT MOVES ACROSS THE AREA. SHOWERS WILL BE MAINLY IN THE
FORM OF SNOW SHOWERS.
WENT WITH MAINLY DRY CONDITIONS FOR MONDAY. NOT REAL COLD FOR
LATE DEC. THERE COULD BE SOME SNOW SHOWERS LATE MONDAY
NIGHT...BUT WENT WITH A DRY FCST FOR NOW.
WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA ANYTIME
FROM SUNDAY INTO MID WEEK...BUT AT THIS TIME...LOOKS LIKE
ANYTHING WOULD BE FAST MOVING...AND MAINLY TO THE SOUTH.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
MAIN CONCERN REMAINS THE LIGHT ICING...AND THE TRAPPED LOW LEVEL
STRATOCU GIVEN THE COLD AIR DAMMING AND THE STRONG INVERSION.
LIGHT FREEZING RAIN AND FREEZING DRIZZLE CONTINUES THROUGH ALL
OF CENTRAL PA. THE LOW STRATOCU CONTINUES TO THICKEN WITH ALL TAF
SITES CURRENTLY IFR. THIS STRATOCU IS RELATED TO THE STRONG
INVERSION PRESENT AND AS SUCH MOST SITES SHOULD REMAIN IFR THROUGH
MOIST OF THE PERIOD. THE SOUTHERN TAF SITES...MAINLY LNS AND MDT
COULD SEE SOME RISE IN CIGS TOMORROW AFTERNOON...THOUGH GIVEN THE
WARM MOIST SOUTHWESTERLY FLOW THAT WILL TAKE OVER...CIGS SHOULD
CONTINUES.
TEMPERATURES THROUGH THE CENTRAL AND WESTERN TERMINALS ARE BELOW
FREEZING AND FREEZING PRECIPITATION SHOULD CONTINUE UNTIL AROUND
9Z...WHERE SFC TEMPERATURES SHOULD INCREASE ABOVE FREEZING. THE
LIGHT RAIN/DRIZZLE REMAINS PROBABLE THROUGH TUESDAY...WITH
REDUCING CIGS CONTINUING INTO TOMORROW NIGHT. LLWS IS POSSIBLE AT
JST DUE TO THE DECOUPLE SFC WINDS AND STRONGER WINDS ALOFT.
THE EASTERN TAF SITES SHOULD SEE PRECIPITATION CONTINUE AND THE
LOW CIGS AND VSBYS CONTINUE...WITH THE VSBYS INCREASE DURING THE
DAYTIME TOMORROW. THE CIG REDUCTIONS SHOULD CONTINUE INTO
WEDNESDAY.
OUTLOOK...
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. BREEZY.
LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
SAT...FAIR AND MOSTLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
PAZ006-010>012-017>019-024>028-033>037-041-042-045-046-049-050-
056-063>065.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/MARTIN
LONG TERM...MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 AM CST TUE DEC 23 2014
.UPDATE...
GIVEN TRENDS...HAVE INCREASE WIND SPEEDS THIS AFTERNOON AND
HOISTED A WIND ADVISORY. THERE IS A BIT OF A CLEARING MOVING
THROUGH THE CWFA WHICH IS HELPING TO MIX WINDS DOWNWARD YIELDING
SPEEDS IN THE LOWER 30S JUST TO OUR NORTH. THE HRX AND REE WEST TEXAS
MESONET SODARS HAVE ALSO INDICATED 50KT SPEEDS NOT FAR OFF THE DECK.
MORE CLOUDINESS CONTINUES TO MOVE SOUTH THROUGH THE PANHANDLE AND
SHOULD HELP SUPPRESS SPEEDS A BIT MORE LATER THIS AFTERNOON BEFORE
BOUNDARY LAYER DECOUPLING ALLOWS SIGNIFICANTLY LOWER SPEEDS THIS
EVENING AND OVERNIGHT.
&&
.AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED NEXT 24 HOURS WITH SOME
POTENTIAL FOR MVFR CEILINGS MAINLY AFTER 03Z AT ALL THREE
TERMINALS. MAIN CONCERN WILL BE GUSTY NORTHERLY WINDS WITH
SUSTAINED SPEEDS IN THE 25 TO 30 KT RANGE ALONG WITH HIGHER GUSTS.
NOTE THAT INCREASING MID LEVEL MOISTURE MAY INCREASE ICING
POTENTIAL THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 525 AM CST TUE DEC 23 2014/
AVIATION...
VFR CONDITIONS IN PLACE AT ALL THREE TAF SITES BUT EXPECT KLBB AND
KPVW TO BOUNCE AROUND BETWEEN VFR AND MVFR. LIGHT PRECIPITATION
MAY IMPACT KPVW AND KLBB OVER THE NEXT 3 HOURS BUT COVERAGE WILL
BE SO SPOTTY AND AMOUNTS SO LIGHT THAT GOING WITH ANY MENTION
WOULD NOT BE WARRANTED. WILL WATCH THROUGH THE MORNING AND AMEND
IF NECESSARY. WIND SPEED WILL CONTINUE TO RAMP UP THROUGH THE DAY
POSSIBLY REACHING THE 25 TO 30 KT SUSTAINED OUT OF THE NORTH WITH
HIGHER GUSTS. ADDITIONAL SHOWERS THIS AFTERNOON MAY IMPACT KCDS
BUT REMAIN EAST OF KLBB AND KPVW. THESE SHOULD BE HIGH ENOUGH TO
KEEP VFR CONDITIONS IN PLACE. AFTER SUNSET...WIND SPEEDS WILL
DECREASE AND VFR CONDITIONS WILL PREVAIL.
JORDAN
PREV DISCUSSION... /ISSUED 432 AM CST TUE DEC 23 2014/
SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>038.
&&
$$
26/99/26
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
525 AM CST TUE DEC 23 2014
.AVIATION...
VFR CONDITIONS IN PLACE AT ALL THREE TAF SITES BUT EXPECT KLBB AND
KPVW TO BOUNCE AROUND BETWEEN VFR AND MVFR. LIGHT PRECIPITATION
MAY IMPACT KPVW AND KLBB OVER THE NEXT 3 HOURS BUT COVERAGE WILL
BE SO SPOTTY AND AMOUNTS SO LIGHT THAT GOING WITH ANY MENTION
WOULD NOT BE WARRANTED. WILL WATCH THROUGH THE MORNING AND AMEND
IF NECESSARY. WIND SPEED WILL CONTINUE TO RAMP UP THROUGH THE DAY
POSSIBLY REACHING THE 25 TO 30 KT SUSTAINED OUT OF THE NORTH WITH
HIGHER GUSTS. ADDITIONAL SHOWERS THIS AFTERNOON MAY IMPACT KCDS
BUT REMAIN EAST OF KLBB AND KPVW. THESE SHOULD BE HIGH ENOUGH TO
KEEP VFR CONDITIONS IN PLACE. AFTER SUNSET...WIND SPEEDS WILL
DECREASE AND VFR CONDITIONS WILL PREVAIL.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 432 AM CST TUE DEC 23 2014/
SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93/14
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
432 AM CST TUE DEC 23 2014
.SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
&&
.LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1137 PM CST MON DEC 22 2014
.UPDATE...
FINAL EVENING UPDATE TO THE FORECAST TO EXPAND ONGOING DENSE FOG
ADVISORY TO INCLUDE AREAS ALONG AND SOUTH OF INTERSTATE 10 AND
WEST OF INTERSTATE 45. VISIBILITIES MAY FLUCTUATE OVER THE
REMAINDER OF THE EVENING HOURS...BUT WILL BE LOW ENOUGH TO PROVIDE
TRAVEL IMPACTS. NO OTHER CHANGES MADE TO ONGOING FORECAST.
HUFFMAN
&&
.PREV DISCUSSION... /ISSUED 1121 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
AVIATION...
A MESSY 18-20 HOURS FOR AVIATION INTERESTS IS ON TAP. VSBYS
CONTINUE TO BOUNCE AROUND BUT MANY SITES ARE NOW REPORTING VSBY
BELOW A MILE. HRRR VSBY PROG SHOWS FOG WITH VSBY 1/2 MILE OR LESS
OVER MUCH OF THE SE HALF OF THE AREA INCLUDING KIAH...KHOU...KLBX
AND KGLS. FCST SOUNDINGS SHOWS A BKN015 DEVELOPING BETWEEN 09-12Z
WITH IFR CIGS DEVELOPING ON TUESDAY MORNING. WARM AIR ADVECTION
WILL YIELD SOME LIGHT RAIN OR DRIZZLE ON TUESDAY AND SOME SCT SHRA
ALONG THE FRONT IN THE LATE MORNING INTO AFTN. WINDS WILL INCREASE
RAPIDLY IN THE WAKE OF TOMORROW AFTNS FRONT. EXPECTING VFR CONDS
TO DEVELOP AFTER 03Z. 43
PREV DISCUSSION... /ISSUED 851 PM CST MON DEC 22 2014/
UPDATE...
TWO PRIMARY CONCERNS WITH THE FORECAST UPDATE TONIGHT...FOG /SOME
POTENTIALLY DENSE/ AND TIMING SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH INCOMING FRONT.
SURFACE ANALYSIS AS OF 7 PM PLACED THE COLD FRONT SURGING THROUGH
TEXAS ROUGHLY ALONG A TEXARKANA TO TEMPLE TO OZONA TO CARLSBAD NM
LINE...WITH SURFACE PRESSURE RISES BEHIND THE FRONT ON THE ORDER
OF 2 TO 3 MB OVER THE PAST 3 HOURS. THE COLDER AIR ASSOCIATED WITH
THIS FRONT IS LAGGING BEHIND THIS BOUNDARY A BIT AS 30S AND 40S
OOZE INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA ...WITH LITTLE
IMMEDIATE CHANGE IN TEMPERATURES BOTH AHEAD AND BEHIND THE FRONT
IN THE MID TO UPPER 50S TO NEAR 60. BECAUSE OF THIS LAG IN COLDER
AIR...LOW TEMPERATURES IN THE LOW 50S IN CENTRAL TEXAS TO LOW 60S
ALONG THE COAST SHOULD BE ON TRACK. PRESENT TIMING FOR THE COLD
FRONT HAS IT ENTERING THE HOUSTON METRO AREA AROUND 7-9 AM TUESDAY
MORNING.
BOTH INLAND AND COASTAL AREAS ARE AT RISK FOR AT LEAST PATCHY FOG
DEVELOPMENT TONIGHT. GENERALLY CLEAR SKIES AND LIGHT WINDS ALONG
AND SOUTH OF THE HIGHWAY 59 CORRIDOR HAVE SET THE STAGE FOR A
RADIATION FOG EVENT...WITH SEVERAL COASTAL COUNTIES ALREADY
REPORTING REDUCED VISIBILITIES FROM FOG. LATEST RAP/HRRR RUNS
SHOW FOG CONTINUING TO DEVELOP ALONG AND SOUTH OF HIGHWAY 59
OVERNIGHT AND THE PREVIOUS FORECAST UPDATE HANDLES THIS
ANTICIPATED DEVELOPMENT WELL. MAIN QUESTION WILL BE HOW DENSE FOG
WILL ACTUALLY GET /VISIBILITY AT KBYY HAS ALREADY DROPPED BELOW 1
MILE/. WILL CONTINUE TO MONITOR TRENDS FOR POTENTIAL DENSE FOG
ADVISORY LATER TONIGHT. FOR MORE INFORMATION REGARDING THE UPDATE
TO THE MARINE FORECAST...PLEASE SEE THE MARINE DISCUSSION APPENDED
BELOW.
REGARDING RAIN CHANCES...REGIONAL RADAR MOSAIC AS OF 830 PM
SHOWED A COMPLEX OF SHOWERS AND THUNDERSTORMS OVER THE PERMIAN
BASIN DEVELOPING ALONG AND BEHIND THE FRONT. 00Z MODEL DATA
CONTINUES TO TRICKLE IN BUT THE LATEST SOLUTIONS STILL INDICATE
THAT THIS ACTIVITY WILL CONTINUE TO SPREAD EAST TOWARDS SOUTHEAST
TEXAS AS THE ASSOCIATED UPPER LEVEL SYSTEM MOVES ACROSS THE STATE.
RAIN CHANCES WILL BEGIN INCREASING ALONG AND BEHIND THE PASSAGE OF
THE FRONT TONIGHT BUT BEST FORCING FOR RAIN DEVELOPMENT WILL BE
ALONG THE 850 MB FRONT...DELAYING HIGHEST RAIN CHANCES AROUND 3-6
HOURS AFTER FRONTAL PASSAGE. CURRENT FORECAST HANDLES THE
EVOLUTION OF TOMORROW/S RAIN...INCREASING FROM WEST TO EAST DURING
THE DAY AS THE UPPER LEVEL TROUGH PASSES...FAIRLY WELL AND NO
CHANGES WERE MADE TO ONGOING RAIN CHANCES.
HUFFMAN
MARINE...
SURFACE DEW PTS ARE IN THE MID 60S AND WATER TEMPS ARE NEAR 60.
SOME PATCHY SEA FOG DEVELOPED NEAR GALVESTON EARLIER AND FEEL SOME
PATCHY FOG COULD PLAGUE MARINE AREAS OFF AND ON THROUGH TUESDAY
AFTERNOON. NOT SURE HOW WIDESPREAD OR DENSE THE FOG WILL BECOME SO
WILL JUST CALL FOR AREAS OF FOG AND WATCH TRENDS.
A STRONG COLD FRONT SHOULD REACH MATAGORDA BAY BY EARLY
AFTERNOON...GALVESTON BAY AROUND 3 PM AND CROSS THE COASTAL WATERS
BY 6 PM. NORTHWEST WINDS WILL INCREASE RAPIDLY IN THE WAKE OF THE
FRONT AND SPEEDS SHOULD EXCEED 20 KNOTS OVER THE ENTIRE MARINE
AREA BY 00Z WITH OCCASIONAL GUSTS TO GALE FORCE. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED FOR THE MARINE AREAS FOR LATE TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT. THE STRONG OFFSHORE FLOW WILL
DRIVE WATER OUT OF GALVESTON BAY AND FEEL THE UPPER REACHES OF
GALVESTON BAY NEAR MORGANS PT AND MANCHESTER WILL SUFFER FROM LOW
WATER ISSUES. A LOW WATER ADVISORY MAY BE REQUIRED LATE TUESDAY
NIGHT INTO WEDNESDAY. MODERATE TO STRONG WINDS WILL PREVAIL ON
WEDNESDAY BEFORE SPEEDS BEGIN TO DECREASE WEDNESDAY NIGHT. AN
ONSHORE FLOW WILL REDEVELOP THURSDAY AND STRENGTHEN ON FRIDAY.
ANOTHER COLD FRONT WILL CROSS THE MARINE AREA ON SATURDAY NIGHT.
43
PREV DISCUSSION... /ISSUED 619 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
VFR CONDS WILL PREVAIL AT MOST TAF SITES THROUGH 06Z WITH SKY
CONDS TRANSITIONING TO MVFR AHEAD OF A COLD FRONT. KGLS HAD A
BRIEF BOUT WITH LOW CIGS EARLIER IN THE EVENING ASSOCIATED WITH
SOME SEA FOG JUST OFF THE COAST. FCST SOUNDINGS SHOW A REASONABLY
DEEP SATURATE LAYER THAT FEEL SOME LIGHT RAIN WILL BE POSSIBLE
ALONG AND BEHIND TUESDAYS COLD FRONT. CIGS WILL ALSO LOWER TO
IFR/LIFR IN THE WAKE OF THE FRONT. WINDS WILL BECOME STRONG IN THE
WAKE OF THE FRONT AS WELL SO WILL CARRY A GUST GROUP AGAIN. VFR
CONDS EXPECTED TO GRADUALLY RETURN AFTER 00Z WED. 43
PREV DISCUSSION... /ISSUED 535 PM CST MON DEC 22 2014/
UPDATE...
QUICK UPDATE TO GRIDS TO ADD MENTION OF PATCHY FOG FOR COASTAL
AREAS THIS EVENING WHERE AFTERNOON VISIBLE SATELLITE AND
GALVESTON WEBCAMS SHOW A LOW STRATUS DECK/FOG BANK SITTING JUST
OFFSHORE. GUIDANCE DEPICTS WINDS BACKING FROM THE SOUTHWEST TO THE
SOUTHEAST DURING THE OVERNIGHT HOURS AND EXPANDED FOG MENTION TO
INLAND AREAS AS THIS OCCURS...WITH AREAS OF FOG LIKELY DEVELOPING
ALONG THE COAST COURTESY CONTINUED LOW LEVEL MOISTURE ADVECTION.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 53 57 37 53 35 / 20 40 10 10 0
HOUSTON (IAH) 58 61 40 54 36 / 20 40 20 10 0
GALVESTON (GLS) 63 65 45 54 44 / 10 30 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR THE FOLLOWING
ZONES: AUSTIN...BRAZORIA...COLORADO...FORT BEND...HARRIS...
JACKSON...MATAGORDA...WALLER...WHARTON.
GM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...14
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1121 PM CST MON DEC 22 2014
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
&&
.AVIATION...
A MESSY 18-20 HOURS FOR AVIATION INTERESTS IS ON TAP. VSBYS
CONTINUE TO BOUNCE AROUND BUT MANY SITES ARE NOW REPORTING VSBY
BELOW A MILE. HRRR VSBY PROG SHOWS FOG WITH VSBY 1/2 MILE OR LESS
OVER MUCH OF THE SE HALF OF THE AREA INCLUDING KIAH...KHOU...KLBX
AND KGLS. FCST SOUNDINGS SHOWS A BKN015 DEVELOPING BETWEEN 09-12Z
WITH IFR CIGS DEVELOPING ON TUESDAY MORNING. WARM AIR ADVECTION
WILL YIELD SOME LIGHT RAIN OR DRIZZLE ON TUESDAY AND SOME SCT SHRA
ALONG THE FRONT IN THE LATE MORNING INTO AFTN. WINDS WILL INCREASE
RAPIDLY IN THE WAKE OF TOMORROW AFTNS FRONT. EXPECTING VFR CONDS
TO DEVELOP AFTER 03Z. 43
&&
.PREV DISCUSSION... /ISSUED 851 PM CST MON DEC 22 2014/
UPDATE...
TWO PRIMARY CONCERNS WITH THE FORECAST UPDATE TONIGHT...FOG /SOME
POTENTIALLY DENSE/ AND TIMING SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH INCOMING FRONT.
SURFACE ANALYSIS AS OF 7 PM PLACED THE COLD FRONT SURGING THROUGH
TEXAS ROUGHLY ALONG A TEXARKANA TO TEMPLE TO OZONA TO CARLSBAD NM
LINE...WITH SURFACE PRESSURE RISES BEHIND THE FRONT ON THE ORDER
OF 2 TO 3 MB OVER THE PAST 3 HOURS. THE COLDER AIR ASSOCIATED WITH
THIS FRONT IS LAGGING BEHIND THIS BOUNDARY A BIT AS 30S AND 40S
OOZE INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA ...WITH LITTLE
IMMEDIATE CHANGE IN TEMPERATURES BOTH AHEAD AND BEHIND THE FRONT
IN THE MID TO UPPER 50S TO NEAR 60. BECAUSE OF THIS LAG IN COLDER
AIR...LOW TEMPERATURES IN THE LOW 50S IN CENTRAL TEXAS TO LOW 60S
ALONG THE COAST SHOULD BE ON TRACK. PRESENT TIMING FOR THE COLD
FRONT HAS IT ENTERING THE HOUSTON METRO AREA AROUND 7-9 AM TUESDAY
MORNING.
BOTH INLAND AND COASTAL AREAS ARE AT RISK FOR AT LEAST PATCHY FOG
DEVELOPMENT TONIGHT. GENERALLY CLEAR SKIES AND LIGHT WINDS ALONG
AND SOUTH OF THE HIGHWAY 59 CORRIDOR HAVE SET THE STAGE FOR A
RADIATION FOG EVENT...WITH SEVERAL COASTAL COUNTIES ALREADY
REPORTING REDUCED VISIBILITIES FROM FOG. LATEST RAP/HRRR RUNS
SHOW FOG CONTINUING TO DEVELOP ALONG AND SOUTH OF HIGHWAY 59
OVERNIGHT AND THE PREVIOUS FORECAST UPDATE HANDLES THIS
ANTICIPATED DEVELOPMENT WELL. MAIN QUESTION WILL BE HOW DENSE FOG
WILL ACTUALLY GET /VISIBILITY AT KBYY HAS ALREADY DROPPED BELOW 1
MILE/. WILL CONTINUE TO MONITOR TRENDS FOR POTENTIAL DENSE FOG
ADVISORY LATER TONIGHT. FOR MORE INFORMATION REGARDING THE UPDATE
TO THE MARINE FORECAST...PLEASE SEE THE MARINE DISCUSSION APPENDED
BELOW.
REGARDING RAIN CHANCES...REGIONAL RADAR MOSAIC AS OF 830 PM
SHOWED A COMPLEX OF SHOWERS AND THUNDERSTORMS OVER THE PERMIAN
BASIN DEVELOPING ALONG AND BEHIND THE FRONT. 00Z MODEL DATA
CONTINUES TO TRICKLE IN BUT THE LATEST SOLUTIONS STILL INDICATE
THAT THIS ACTIVITY WILL CONTINUE TO SPREAD EAST TOWARDS SOUTHEAST
TEXAS AS THE ASSOCIATED UPPER LEVEL SYSTEM MOVES ACROSS THE STATE.
RAIN CHANCES WILL BEGIN INCREASING ALONG AND BEHIND THE PASSAGE OF
THE FRONT TONIGHT BUT BEST FORCING FOR RAIN DEVELOPMENT WILL BE
ALONG THE 850 MB FRONT...DELAYING HIGHEST RAIN CHANCES AROUND 3-6
HOURS AFTER FRONTAL PASSAGE. CURRENT FORECAST HANDLES THE
EVOLUTION OF TOMORROW/S RAIN...INCREASING FROM WEST TO EAST DURING
THE DAY AS THE UPPER LEVEL TROUGH PASSES...FAIRLY WELL AND NO
CHANGES WERE MADE TO ONGOING RAIN CHANCES.
HUFFMAN
MARINE...
SURFACE DEW PTS ARE IN THE MID 60S AND WATER TEMPS ARE NEAR 60.
SOME PATCHY SEA FOG DEVELOPED NEAR GALVESTON EARLIER AND FEEL SOME
PATCHY FOG COULD PLAGUE MARINE AREAS OFF AND ON THROUGH TUESDAY
AFTERNOON. NOT SURE HOW WIDESPREAD OR DENSE THE FOG WILL BECOME SO
WILL JUST CALL FOR AREAS OF FOG AND WATCH TRENDS.
A STRONG COLD FRONT SHOULD REACH MATAGORDA BAY BY EARLY
AFTERNOON...GALVESTON BAY AROUND 3 PM AND CROSS THE COASTAL WATERS
BY 6 PM. NORTHWEST WINDS WILL INCREASE RAPIDLY IN THE WAKE OF THE
FRONT AND SPEEDS SHOULD EXCEED 20 KNOTS OVER THE ENTIRE MARINE
AREA BY 00Z WITH OCCASIONAL GUSTS TO GALE FORCE. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED FOR THE MARINE AREAS FOR LATE TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT. THE STRONG OFFSHORE FLOW WILL
DRIVE WATER OUT OF GALVESTON BAY AND FEEL THE UPPER REACHES OF
GALVESTON BAY NEAR MORGANS PT AND MANCHESTER WILL SUFFER FROM LOW
WATER ISSUES. A LOW WATER ADVISORY MAY BE REQUIRED LATE TUESDAY
NIGHT INTO WEDNESDAY. MODERATE TO STRONG WINDS WILL PREVAIL ON
WEDNESDAY BEFORE SPEEDS BEGIN TO DECREASE WEDNESDAY NIGHT. AN
ONSHORE FLOW WILL REDEVELOP THURSDAY AND STRENGTHEN ON FRIDAY.
ANOTHER COLD FRONT WILL CROSS THE MARINE AREA ON SATURDAY NIGHT.
43
PREV DISCUSSION... /ISSUED 619 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
VFR CONDS WILL PREVAIL AT MOST TAF SITES THROUGH 06Z WITH SKY
CONDS TRANSITIONING TO MVFR AHEAD OF A COLD FRONT. KGLS HAD A
BRIEF BOUT WITH LOW CIGS EARLIER IN THE EVENING ASSOCIATED WITH
SOME SEA FOG JUST OFF THE COAST. FCST SOUNDINGS SHOW A REASONABLY
DEEP SATURATE LAYER THAT FEEL SOME LIGHT RAIN WILL BE POSSIBLE
ALONG AND BEHIND TUESDAYS COLD FRONT. CIGS WILL ALSO LOWER TO
IFR/LIFR IN THE WAKE OF THE FRONT. WINDS WILL BECOME STRONG IN THE
WAKE OF THE FRONT AS WELL SO WILL CARRY A GUST GROUP AGAIN. VFR
CONDS EXPECTED TO GRADUALLY RETURN AFTER 00Z WED. 43
PREV DISCUSSION... /ISSUED 535 PM CST MON DEC 22 2014/
UPDATE...
QUICK UPDATE TO GRIDS TO ADD MENTION OF PATCHY FOG FOR COASTAL
AREAS THIS EVENING WHERE AFTERNOON VISIBLE SATELLITE AND
GALVESTON WEBCAMS SHOW A LOW STRATUS DECK/FOG BANK SITTING JUST
OFFSHORE. GUIDANCE DEPICTS WINDS BACKING FROM THE SOUTHWEST TO THE
SOUTHEAST DURING THE OVERNIGHT HOURS AND EXPANDED FOG MENTION TO
INLAND AREAS AS THIS OCCURS...WITH AREAS OF FOG LIKELY DEVELOPING
ALONG THE COAST COURTESY CONTINUED LOW LEVEL MOISTURE ADVECTION.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 53 57 37 53 35 / 20 40 10 10 0
HOUSTON (IAH) 58 61 40 54 36 / 20 40 20 10 0
GALVESTON (GLS) 63 65 45 54 44 / 10 30 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR THE FOLLOWING
ZONES: BRAZORIA...FORT BEND...JACKSON...MATAGORDA...WHARTON.
GM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
945 PM EST WED DEC 24 2014
.SYNOPSIS...
A WEDGE OF HIGH PRESSURE ALONG THE EASTERN SLOPES OF THE BLUE
RIDGE WILL SLOWLY GIVE WAY TO AN APPROACHING COLD FRONT OVERNIGHT.
THIS FRONT WILL MOVE THROUGH MOST OF THE REGION BY EARLY THURSDAY
...BRINGING COLDER TEMPERATURES AND GUSTY WINDS AS IT PASSES.
HIGH PRESSURE WILL THEN BUILD OVER THE EASTERN UNITED STATES INTO
THE WEEKEND WITH GENERALLY FAIR WEATHER EXPECTED INTO SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 925 PM EST WEDNESDAY...
COLD FRONT NOW PUSHING ACROSS THE FAR WESTERN COUNTIES SHOULD
REACH THE BLUE RIDGE BY MIDNIGHT AND OUT EAST DURING THE EARLY
MORNING HOURS. MOST SHOWERS HAVE ALL BUT DISSIPATED ALONG THE
BOUNDARY UPON ENCOUNTERING THE LINGERING WEDGE BUT STILL APPEARS A
FEW LIGHTER BANDS OF SHOWERS POSSIBLE OVER THE WEST DURING THE
NEXT COUPLE OF HOURS. HOWEVER NOT ENOUGH TO KEEP ANY THUNDER GOING
NW WITH A GRADUAL REDUCTION IN POPS WEST UNTIL SEEING THE BRIEF
UPSLOPE KICK IN LATER ON. OTHER CONCERN IS OUT EAST WHERE THE
FRONT WILL LIKELY SLOW UNDER THE SW FLOW ALOFT ALLOWING PERHAPS
ANOTHER SPEED MAX TO ZIP UP FROM THE SOUTH INTO THE EARLY MORNING
HOURS. LATEST HRRR CONTINUES TO SUGGEST A FEW ADDED HOURS OF RAIN
ESPCLY PIEDMONT AND SUPPORTED BY THE 00Z NAM SO ADDED IN MORE
CHANCE POPS EAST OVERNIGHT ESPCLY GIVEN FILLING BACK IN OF PRECIP
ON REGIONAL RADARS TO THE SOUTH ATTM. OTRW SEEING A TEMP DROP OF
ALMOST 10 DEGREES IN AN HOUR DURING THE FROPA WITH GUSTS TO 30-35
KTS BUT STILL BELOW ADVISORY GIVEN LEVELING OFF OF SPEEDS ONCE THE
BOUNDARY CROSSES. EXPECT FOG TO FINALLY FADE ENOUGH AFTER MIDNIGHT
TO DROP MENTION FOR THE MOST PART OVERNIGHT AS WELL. BUMPED UP LOW
TEMPS IN THE EAST WHERE ONCE THE WEDGE BREAKS EXPECT A BRIEF TEMP
SURGE FOR A COUPLE HOURS BEFORE GRADUAL COOLING REDEVELOPS BEHIND
THE FRONT. HOWEVER GIVEN MIXING EXPECT LOWS TO BE A FEW DEGREES
WARMER THAN EARLIER THOUGHT.
PREVIOUS UPDATE AS OF 520 PM EST WEDNESDAY...
SENT AN UPDATE TO BOOST DENSE FOG COVERAGE ALONG/EAST OF THE BLUE
RIDGE THIS EVENING BEFORE THE COLD FRONT FINALLY ARRIVES AND HELPS
MIX THINGS OUT BEFORE MIDNIGHT. ALSO ISSUED A SPS FOR THE
FOOTHILLS AND PIEDMONT GIVEN THE QUICK DROPOFF IN VISIBILITIES
OVER THE PAST HOUR. MAY NEED A BRIEF ADVISORY IF CONDITIONS WORSEN
BUT HOLDING OFF FOR NOW GIVEN THE GRADUAL APPROACH OF THE FRONT
FROM THE WEST. ALSO TWEAKED POPS DOWN AND ADDED MORE DRIZZLE BLUE
RIDGE EAST WHILE DELAYING CONVECTION OVER THE WEST. MOST LATEST
SHORT TERM SOLUTIONS QUICKLY WEAKEN THIS SHALLOW CONVECTION UPON
CROSSING THE WESTERN SLOPES IN THE NEXT COUPLE OF HOURS BUT
SOMETHING TO WATCH. TEMPS REMAIN STUCK IN THE 40S ACROSS THE
CENTRAL AND EAST SO ADJUSTED DOWN FOR STEADY READINGS THERE THIS
EVENING BEFORE SEEING A QUICK JUMP WHEN THE FRONT ARRIVES AFTER
00Z.
PREVIOUS DISCUSSION AS OF 340 PM EST WEDNESDAY...
AT 3 PM...THE WEDGE OF COOL SHALLOW AIR REMAINED ALONG AND EAST
OF THE BLUE RIDGE. THIS MORNING...A SHORT WAVE PASSED OVER THIS
WEDGE AND BROUGHT A FAIR AMOUNT OF RAIN (0.50 TO 1.50 INCHES) TO
THE REGION. THIS WAVE HAS PASSED WITH ONLY LIGHT RAIN/DRIZZLE LEFT
IN ITS WAKE. GRAY CLOUDY CONDITIONS WILL PERSIST INTO THIS EVENING
WHILE A LULL IN THE RAIN WILL LAST FOR A FEW HOURS BEFORE A COLD
FRONT AND ASSOCIATED SHOWERS ENTER THE WEST LATE THIS
AFTERNOON...EXITING THE PIEDMONT LATE THIS EVENING. THE WEDGE HAS
LEFT MOST OF THE AREA IN A STABLE ENVIRONMENT BUT CAN NOT RULE OUT
A RUMBLE OF THUNDER FROM ELEVATED CONVECTION AS THE COLD FRONT
PASSES THIS EVENING.
SHOWERS WITH THE FRONT MAY HAVE SOME GUSTY WINDS WITH THEM...BUT
IT WILL BE THE SHARP PRESSURE RISES BEHIND THE FRONT THAT WILL
BRING A FEW HOURS OF BREEZY AND GUSTY CONDITIONS TO THE REGION.
THE STRONGER LONGER LASTING BREEZY AND GUSTY WINDS WILL OCCUR
EARLY CHRISTMAS MORNING WITH A TIGHT PRESSURE GRADIENT...MODEST
COLD AIR ADVECTION AND A 50 KT LOW LEVEL JET. HIGH PRESSURE BUILDS
IN QUICKLY THURSDAY AFTERNOON TO SHUT DOWN THE WINDS.
AS THE WEDGE ERODES...TEMPERATURES ARE WARMING INTO THE MID TO
UPPER 50S. AREA ALONG AND EAST OF THE BLUE RIDGE...PARTICULARLY IN
THE FOOTHILLS AND PIEDMONT COUNTIES...MAY NOT SEE HIGH
TEMPERATURES TODAY UNTIL THIS EVENING (5P-7P). ONCE THE FRONT
MOVES EAST...TEMPERATURES WILL SLOWLY DROP INTO THE 30S AND 40S.
AS THE UPPER LEVEL TROUGH PASSES OVERHEAD FRIDAY MORNING...A FEW
SHOWERS ARE POSSIBLE. TEMPERATURES AND BOUNDARY LAYER ARE TO WARM
FOR SNOW EXCEPT FOR HIGHER ELEVATIONS AND WESTERN SLOPES. AFTER A
BREEZY COOL MORNING...AFTERNOON HIGHS WILL WARM INTO THE 40S WEST
TO 50S EAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 250 PM EST WEDNESDAY...
TRANQUIL AND MILD CONDITIONS ARE IN STORE FOR THE INITIAL POST-
CHRISTMAS PERIOD OVER THE CENTRAL/SOUTHERN APPALACHIAN REGION. A
SURFACE AND UPPER RIDGE OF HIGH PRESSURE CENTERED OVER THE
SOUTHEASTERN U.S. WILL DOMINATE THE PATTERN IN OUR REGION FOR
SEVERAL DAYS AS UPPER TROUGHING AND STORMINESS IS CONFINED TO THE
WESTERN CONUS. VERY MILD TEMPS ON FRIDAY WITH WIDESPREAD 50S
LIKELY FOR HIGHS UNDER A PLEASANT LATE DECEMBER SUN. WINTER
WEATHER LOVERS PREPARE TO BE LESS THAN PLEASED.
THE HIGH WILL SHIFT OFF THE EAST COAST BY LATE SATURDAY AS HEIGHT
FALLS AND A COLD FRONT OVER THE MID-MISSISSIPPI VALLEY SLOWLY PUSH
EAST. SKIES WILL BE CLEAR FRIDAY NIGHT AND MOST OF SATURDAY WITH
TEMPERATURES AGAIN RUNNING 10-15F ABOVE LATE DECEMBER
NORMALS...LOWS IN LOW TO MID-30S AND HIGHS LOW 50S TO NEAR 60.
HIGH CLOUDS WILL INCREASE LATE SATURDAY AHEAD OF THE FRONT WITH
ANOTHER MILD NIGHT IN STORE AS TEMPS LIKELY TO REMAIN ABOVE
FREEZING IN NEARLY ALL AREAS. POPS SLOWLY INCREASE AS WELL TO CHC
BY EARLY SUNDAY IN THE FAR WEST WITH RAIN AS THE P-TYPE IN ALL BUT
VERY COLDEST LOCATIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
SUNDAY INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
A LITTLE MORE CONFIDENCE AT THE BEGINNING OF THIS PERIOD...SO
HAVE SOME LIKELY AND HIGH CHC POPS IN FOR SUNDAY...BUT ALL
RAIN...AND MOST LIKELY LIGHT. AS WE GET INTO THE WEEK...THE LARGE
SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A LITTLE COOLER
THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE TEMPERATURE
FORECAST. WHILE I HAVE LOWERING POPS EACH DAY...LARGELY DUE TO
INCREASING UNCERTAINTY...AM KEEPING A LOW CHC TO SLIGHT CHC IN
THROUGH THE PERIOD WITH MORE INDICATION OF SOME WINTRY PRECIP AS
WE GET INTO TUES NIGHT AND WED. OVERALL...FORECAST REALLY REFLECTS
A VERY BROAD BRUSH RATHER THAN GOING EXACTLY WITH ANY ONE
SOLUTION...AND EXPECT THERE WILL BE QUITE A FEW CHANGES TO THE
EARLY WEEK FORECAST AS WE GET INTO THE WEEKEND. NOT MUCH CHANCE
FOR A MAJOR STORM DURING THIS PERIOD...AND AFTER SUNDAY ITS
POSSIBLE THAT DRY BUT COOL HIGH PRESSURE MANAGES TO DOMINATE...BUT
BEST GUESS FOR NOW IS SOMETHING IN BETWEEN. AS ALWAYS...STAY
TUNED!
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AS OF 610 PM EST WEDNESDAY...
POOR FLYING CONDITIONS CONTINUE ACROSS MOST OF THE REGION THIS
EVENING WITH LOW CLOUDS...FOG AND DRIZZLE CAUSING PERIODIC
LOWERING TO IFR/LIFR FROM KROA EAST...WITH OVERALL MVFR CIGS TO
THE WEST. COLD FRONT NOW JUST WEST OF THE MOUNTAINS WILL BE
PRECEDED BY A BROKEN BAND OF SHOWERS AND POSSIBLE ISOLATED TSRA
WITH STRONG WINDS BETWEEN 00Z/7PM AND 02Z/9PM AT KBLF/KLWB AND
PERHAPS KBCB SHORTLY THEREAFTER. MIXING AHEAD OF THIS FRONT SHOULD
FINALLY HELP TO MIX OUT THE LOW CONDITIONS OUT EAST WITH
IMPROVEMENT TO MVFR POSSIBLE BY MIDNIGHT EAST OF THE BLUE RIDGE
AND THEN VFR OVERNIGHT. SOME POTENTIAL TO SEE A FEW WESTERN
SHOWERS SNEAK OUT EAST WHILE LATEST SHORT TERM GUIDANCE INDICATES
PERHAPS ANOTHER ROUND OF SHOWERS DEVELOPING OUT EAST BUT LOW
CONFIDENCE AT THIS POINT SO WONT ADD. HOWEVER WILL AGAIN CONTINUE
TO MENTION LLWS FOR THE STRONG SW JET JUST ABOVE THE SURFACE OUT
EAST WHILE MIXING TO THE GROUND PROMPTS ADDITION OF TEMPO STRONGER
WIND GUSTS TO 40 KTS OUT WEST WITH THE FRONT.
EXPECT A RETURN TO VFR OUT EAST OF THE MOUNTAINS LATE TONIGHT WITH
PROLONGED MVFR LINGERING MOUNTAINS WITH KBLF LIKELY DROPPING BACK
INTO IFR/LIFR BEHIND THE FRONT PER DEVELOPING UPSLOPE. WEST WINDS
SHOULD ALSO CRANK UP IN THE WAKE OF THE FRONT WITH GUSTS TO 30 KTS
POSSIBLE MOUNTAINS AFTER MIDNIGHT.
THURSDAY...MVFR CEILINGS AND UPSLOPE RAIN/SNOW SHOWERS SHOULD
PERSIST IN THE MOUNTAINS...MAINLY KBLF/KLWB INTO THE AFTERNOON WITH
VFR CONDITIONS RETURNING IN THE PIEDMONT. IN BETWEEN...SOME
LINGERING MVFR STRATO-CU POSSIBLE AROUND KBCB/KROA THURSDAY
MORNING BEFORE THINGS MIX OUT UNDER GUSTY WESTERLY WINDS BY
MIDDAY. WINDS AGAIN MAY GUST TO 25-30 KTS THURSDAY MORNING BEFORE
QUICKLY DIMINISHING DURING THURSDAY AFTERNOON AS HIGH PRESSURE
BUILDS IN.
EXTENDED DISCUSSION...
THURSDAY NIGHT AND FRIDAY HIGH PRESSURE SHOULD BUILD OVER THE
SOUTHEAST...WHICH WILL PROVIDE VFR WEATHER WITH LIGHTER WINDS.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. GIVEN
THE SLOWER TRENDS...APPEARS WEATHER MAY STAY VFR FOR SATURDAY WITH
SUB-VFR CONDITIONS RETURNING WITH CLOUDS/PRECIP ON SUNDAY FOR NOW.
BOUNDARY MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT
WEEK WITH POSSIBLE RETURN TO VFR MONDAY AFTERNOON AT THIS POINT.
&&
.HYDROLOGY...
AS OF 335 PM EST WEDNESDAY...
WITH THE BULK OF THE RAINFALL HAVING SHIFTED NORTHEAST THIS
AFTERNOON STORM TOTAL RAINFALL FROM THE RAIN GAGE NETWORK THROUGH
18Z HAS RANGED GENERALLY FROM 0.50 TO 1.50 INCHES WITH THE HIGHEST
AMOUNTS OVER NW NORTH CAROLINA IN PARTS OF THE UPPER NEW AND
TENNESSEE BASINS RIVER BASIN AND ACROSS THE UPPER DAN BASIN.
RIVERS HAVE SEEN ONLY MINOR RISES OF A FEW FEET AND DO NOT EXPECT
ANY GAGED LOCATIONS TO EVEN REACH ACTION STAGE. IN FACT LONGER-
TERM PRECIPITATION DEFICITS EXTANT OVER PARTS OF THE PIEDMONT WILL
REMAIN AFTER THIS EVENT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/RCS
NEAR TERM...JH/RCS
SHORT TERM...PC
LONG TERM...SK
AVIATION...JH/RCS
HYDROLOGY...PC
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
938 PM CST WED DEC 24 2014
.UPDATE...
SHOULD SEE THE LAST BAND OF MIXED PRECIPITATION OVER FAR EASTERN
WISCONSIN...MAINLY VERY LIGHT SNOW MIXED WITH RAIN NORTH OF
I-94...WITH DRIZZLE...LIGHT RAIN...AND SOME SLEET FROM I-94
SOUTH...EXITING OUT OVER LAKE MICHIGAN BETWEEN 1030 PM AND 11 PM.
AIR TEMPERATURES ARE STILL ABOVE FREEZING BUT WILL SLOWLY FALL TO
AROUND 30F...THOUGH NOT UNTIL WELL AFTER THE PCPN HAS GONE. WITH ROAD
SURFACE TEMPS STILL WELL ABOVE 32F LITTLE IN THE WAY OF ICING
EXPECTED. WEAK RETURNS ON UPSTREAM RADARS INDICATE WE COULD SEE A
FEW SNOW FLURRIES AHEAD OF A WEAK RIPPLE CROSSING IL OVERNIGHT
INTO THURSDAY MORNING...BUT NO ACCUMULATIONS EXPECTED.
&&
.AVIATION/06Z TAFS/...
ANY MIXED PCPN SHOULD BE OUT OF KMKE AND KENW BY 0430Z. CIGS ARE
CLIMBING TO ABOVE 1K FT...WITH SOME MVFR CIGS IN THE WESTERN
FORECAST AREA. LATEST RAP SOUNDINGS SHOW CIGS AT 2K FT OR HIGHER
WILL BE SHORT-LIVED SO WILL KEEP CIGS AT FUEL ALTERNATE MINIMUMS
THROUGH THE OVERNIGHT...THEN RAISE THEM TO MVFR MID MORNING...AND
VFR BY LATE MORNING. EASTERN TAF SITES HAVE THE BEST CHANCE TO SEE
CLOUDS SCATTER OUT THURSDAY AFTERNOON...WITH OVERCAST SKIES
RETURNING THURSDAY EVENING WITH WARM ADVECTION ON DEVELOPING SW
WINDS AHEAD OF DEEPENING WESTERN TROUGH. NAM GUIDANCE WANTS TO
DROP CIGS BACK TO FUEL ALTERNATE MINIMUMS BY 03Z AT KMSN AND
BETWEEN 06Z AND 09Z AT KMKE...EVEN AS LOW AS IFR BY 09Z 12/26 AT
KMKE. WILL KEEP CIGS NO LOWER THAN 1000 TO 1500 FT FOR NOW.
&&
.MARINE...
LAKESHORE OB SITES NOT GUSTING TO CRITERIA...BUT LATEST RAP AND
00Z NAM SOUNDINGS OVER THE WATER INDICATE MIXING UP TO 24-27 KNOT
WINDS AT LEAST INTO EARLY THURSDAY MORNING. WILL LET ADVISORY
CONTINUE AND LET OVERNIGHT CREW RE-ASSESS.
&&
.PREV DISCUSSION... /ISSUED 320 PM CST WED DEC 24 2014/
TONIGHT AND CHRISTMAS DAY...CONFIDENCE - HIGH
SURFACE TEMPERATURES ARE EXPECTED TO MAINLY STAY ABOVE FREEZING
DURING THE TIME OF PRECIP CHANCES. WITH SATURATION ONLY UP TO
ABOUT -10C AND MUCH OF THE SATURATED LAYER BELOW FREEZING...PRECIP
TYPE WILL DEPEND ON ICE CRYSTAL FORMATION. SEEMS A RAIN/SNOW MIX
IS THUS THE WAY TO GO THROUGH THE REMAINDER OF THIS EVENT. EITHER
WAY...PRECIP AMOUNTS WILL BE VERY LIGHT...LIKELY STRUGGLING TO
MEASURE RAIN OR SNOW MOST PLACES.
LOW CLOUDS WILL LIKELY LINGER THROUGH AT LEAST TONIGHT...WITH A
CHANCE FOR SOME SUNSHINE BY TOMORROW AFTERNOON. THE SUN MAY BE
FILTERED THROUGH HIGH CLOUDS...BUT SUN OF ANY FORM WOULD PROBABLY BE
WELCOME AFTER THIS RECENT STRETCH OF CLOUDS. WITH THE THE POSSIBLE
AFTERNOON SUN...MILD SOUTHERLY LOW LEVEL FLOW...AND INCREASING TEMPS
ALOFT...LOOKS LIKE HIGHS WILL BE UP NEAR 40 FOR CHRISTMAS.
THURSDAY NIGHT THROUGH SATURDAY...CONFIDENCE - MEDIUM.
SHORT TERM GUIDANCE IN FAIR AGREEMENT ON INCOMING SHORT WAVE TROF
INTO THE PACIFIC NORTHWEST DIGGING SOUTHEAST AND AMPLIFYING. ONCE
WEAK HIGH PRESSURE PASSES BY THE EAST...INCREASING SOUTHERLY WINDS
AHEAD OF UPSTREAM TROFFING WILL PULL DEEPER COLUMN MOISTURE
NORTHWARD INTO THE REGION THURSDAY NIGHT INTO SATURDAY. COLUMN PWAT
VALUES INCREASE SLIGHTLY TO AROUND ONE HALF INCH DURING THIS
TIME...WHICH IS AROUND THE 75TH PERCENTILE FOR LATE DECEMBER.
WHILE CONFIDENCE IS HIGHER ON MILDER TEMPS AND DEEPER
MOISTURE...SHORT TERM GUIDANCE DIFFER ON TIMING OF EJECTION OF
UPSTREAM TROF ACROSS THE PLAINS. PREFERRING SIMILAR NAM AND ECMWF
SOLUTIONS WHICH HAVE BETTER Q-VECTOR CONVERGENCE AND SYNOPTIC SCALE
FORCING AFFECTING SRN WI LATER FRIDAY NIGHT INTO SATURDAY. HENCE
PREFER SLIGHTLY SLOWER SOLUTION WHICH KEEPS WARMER LOW LEVEL THERMAL
BOUNDARY ACROSS SRN WI INTO SATURDAY...RESULTING IN A BETTER CHANCE
FOR MORE LIQUID PRECIP IN THE EAST. SOME WEAK LOW TO MID LAYER
FRONTOGENETICAL FORCING ENHANCING SYNOPTICS...SO WL BUMP UP POPS TO
HIGH CHANCE CATEGORY FOR SAT MRNG. TEMPS EXPECTED TO BE ABOVE
FREEZING MOST OF THE DAY SO ONLY LIGHT SNOW ACCUMULATIONS...IF
ANY...EXPECTED.
SATURDAY NIGHT THROUGH WEDNESDAY...CONFIDENCE - MEDIUM.
WILL NEED TO CARRY SMALL POPS FOR LINGERING PRECIP INTO SATURDAY
EVENING AS BOTH ECMWF AND GEM IN AGREEMENT ON SLOWER EWD PROGRESS OF
SFC TROF AS WELL AS WEAKENING ELONGATED ELEVATED TROFFING. HOWEVER
EXPECT THIS FEATURE TO SLIDE OFF TO THE EAST SAT NGT IN RESPONSE TO
UPSTREAM KICKER WAVE MOVING ACROSS THE WESTERN CONUS OVER THE
WEEKEND. COLDER...MORE SEASONAL TEMPERATURES ARE EXPECTED TO RETURN
BEHIND THE DEPARTING SYSTEM FOR THE WEEKEND.
WEAK HIGH PRESSURE BETWEEN THESE TWO FEATURES WILL RESULT IN DRY BUT
COLDER CONDITIONS FOR SUNDAY. DURING THIS PERIOD...INCREASING
NORTHWEST WINDS ACROSS SOUTHERN CANADA WILL BE PULLING COLDER AIR
INTO THE BORDER AREA...WHICH WILL BE POISED TO SURGE ACROSS THE
UPPER MIDWEST EARLY NEXT WEEK.
AN AMPLIFYING LONG WAVE TROF OVER THE CENTRAL CONUS IN RESPONSE TO
LOW PRESSURE MOVING ACROSS THE SOUTHEAST CONUS WILL ALLOW THE COLDER
AIR TO SURGE SWD AND AFFECT SRN WI HEADING INTO THE NEW YEAR.
HOWEVER STEERING FLOW ALOFT REMAINS MORE WESTERLY AS COLD AIR
SETTLES INTO THE REGION. LAYER RH LOOKS LOW...BUT A WEAK WAVE
MOVING IN WESTERLIES MAY BRING A PERIOD OF -SN TO THE AREA MON AND
TUE. 925H TEMPS FALL TO AROUND -20C BY WED...WHICH WOULD RESULT IN
DAYTIME TEMPS IN THE SINGLE DIGITS AND TEENS WITH A LACK OF
SIGNIFICANT SNOW COVER. SOME RECOVERY IN TEMP EXPECTED FOR NEW
YEARS DAY.
AVIATION/00Z TAFS/...
LATEST MODELS CONTINUE TO THE DOWNWARD TREND IN PRECIP
CHANCES...WITH NO APPRECIABLE RAIN OR SNOW EXPECTED THROUGH THE
REMAINDER OF THE DAY. STILL MAY SEE A LITTLE LIGHT SNOW OR RAIN AT
TIMES INTO THE EVENING HOURS AS THE UPPER THROUGH SWINGS THROUGH.
A FEW LOWER VISIBILITIES ARE LINGERING OUT THERE...BUT THESE SHOULD
CONTINUE TO IMPROVE THROUGH THE AFTERNOON. LOW CLOUDS WILL LIKELY
PERSIST INTO TONIGHT. SHOULD THEN SEE A RETURN TO VFR CONDITIONS BY
MID OR LATE THURSDAY MORNING.
MARINE...
THE SMALL CRAFT ADVISORY IN EFFECT FOR THIS EVENING THROUGH
CHRISTMAS MORNING IS LOOKING A BIT MORE MARGINAL...BUT STILL
PROBABLY WORTH KEEPING. BEST CHANCE FOR GUSTS TO 25 KNOTS WILL BE
TOWARD OPEN WATERS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST THURSDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/THURSDAY AND AVIATION/MARINE...DDV
THURSDAY NIGHT THROUGH WEDNESDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1129 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 913 PM CST MON DEC 22 2014
CONFIDENCE IS INCREASING THAT SOME HEAVIER SNOWS WILL BE MAKING IT
INTO CLARK COUNTY TONIGHT INTO TOMORROW AFTERNOON...SO HAVE
DECIDED TO ADD THEN INTO THE ADVISORY. 23.01Z RAP SOUNDINGS FROM
CLARK COUNTY SHOW THE THERMAL PROFILE STAYING BELOW FREEZING WITH
THE EXCEPTION OF THE NEAR SURFACE LAYER WHICH ONLY GETS TO 33F OR
SO. AT LEAST FOR THIS EVENING 34F APPEARS TO BE THE CHANGEOVER
LEVEL FROM RAIN TO SNOW...SO WILL USE THAT INTO TONIGHT INTO
TOMORROW. OUTSIDE OF THE ADJUSTMENT TO ADD CLARK TO THE
ADVISORY...WILL BE WAITING ON THE 23.00Z DATA TO COME IN BEFORE
MAKING ANY CHANGES TO THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
CHALLENGES CONTINUE WITH THE WINTER STORM THIS EVENING THROUGH
TUESDAY...NAMELY PRECIPITATION TYPE AND SNOW AMOUNTS. 22.12Z MODEL
SUITE MASS FIELDS IN GOOD OVERALL AGREEMENT THROUGH THE EVENT.
HOWEVER...MINOR DIFFERENCES IN THE THERMAL PROFILES...COMPOUNDED
BY THE FACT THAT SOUNDINGS WOBBLE ABOUT THE ZERO DEGREE ISOTHERM
MAKE PRECIPITATION TYPE PARTICULARLY DIFFICULT. ALL SAID...THERE
HAS STILL BEEN A SOUTHERN TREND IN THE TRACK OF THE SURFACE LOW AS
IT BRIEFLY DIPS INTO NORTHERN MO THIS EVENING BEFORE EJECTING
NORTHEASTWARD ACROSS SOUTHERN WI ON TUESDAY. THIS ALLOWS THE
PRIMARY DEFORMATION AXIS TO SET-UP ACROSS THE NORTHWEST THIRD OF
THE FORECAST AREA AND ENHANCES THE CHANCE FOR ACCUMULATING
SNOWFALL PRIMARILY ON TUESDAY.
FOR THIS EVENING...FIRST WAVE OF PRECIPITATION WILL LIFT ACROSS
THE FORECAST AREA. THERMAL PROFILES ARE WARM ENOUGH FOR MOSTLY
RAIN...EXCEPT ACROSS TAYLOR/CLARK COUNTIES WHERE SOME ACCUMULATING
SNOW (LESS THAN AN INCH) IS POSSIBLE. TEMPERATURES WILL CHANGE
VERY LITTLE AND REMAIN IN THE MID TO UPPER 30S.
FOR TONIGHT...LOW-MID LEVEL WARM FRONT WILL SURGE NORTHWARD AS
SURFACE LOW MOVES INTO NORTHEAST IA. A SECONDARY WAVE OF
PRECIPITATION WILL SWEEP ACROSS THE FORECAST AREA FROM SOUTH TO
NORTH ALONG AXIS OF STRONG WARM AIR ADVECTION AND ISENTROPIC LIFT.
IN GENERAL...EXPECT A NARROW CORRIDOR OF A RAIN SNOW MIX NEAR THE
TRACK OF THE SURFACE LOW WITH SNOW TO THE NORTHWEST AND RAIN TO
THE SOUTHEAST. MODELS ARE HINTING AT A 925 TO 850 HPA WARM TONGUE
TO WRAP AROUND THE LOW BY TUESDAY MORNING...BUT ITS IMPACT ON
PRECIPITATION TYPE SHOULD BE FELT MAINLY FOR AREAS THAT WILL
ALREADY BE SEEING RAIN.
ACCUMULATING SNOW IS MAINLY A CONCERN ON TUESDAY WEST OF A LINE
FROM OELWEIN TO LA CROSSE TO WAUSAU. EXPECT RAIN OR A RAIN/SNOW MIX
FARTHER SOUTH AND EAST. WARM AIR THIS EVENING AND A SLOW
TRANSITION TO A COLDER AIR MASS MAY INITIALLY LIMIT SNOWFALL...
BUT MODELS SHOW ALL BUT THE NEAR SURFACE LAYER DROPPING BELOW
FREEZING BY 23.12Z. EXPECT STRONG LIFT FROM 5 TO 8 UBAR/SECOND
ALONG THE -15 C ISOTHERM WITHIN DEFORMATION SNOW AXIS TO GENERATE
SNOWFALL RATES HIGH ENOUGH TO OVERCOME WARM SURFACE TEMPERATURES
AND ACCUMULATE. NEW FORECAST CALLS FOR 1-3 INCHES OF HEAVY WET
SNOW ACROSS PORTIONS OF NORTHEAST IA/SOUTHEAST MN/WESTERN WI WITH
THE HIGHEST AMOUNTS ACROSS ELEVATED TERRAIN. THIS MATCHES FAIRLY
WELL WITH LATEST GFS/NAM COBB OUTPUT AND SREF PLUMES. ACCUMULATING
SNOWFALL WILL BE BEST REALIZED ACROSS GRASSY SURFACES...BUT COULD
STILL SEE SLUSH ACCUMULATIONS ON UNTREATED ROADWAYS MAKING TRAVEL
DIFFICULT...ESPECIALLY DURING THE TUESDAY MORNING COMMUTE. WILL
KEEP CURRENT WINTER WEATHER ADVISORY FOR TAYLOR COUNTY AND MONITOR
ALL OTHER AREAS FOR POSSIBLE EXPANSION. SEE SPS FOR ADDITIONAL
INFORMATION.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
PRECIPITATION WILL DISSIPATE TUESDAY NIGHT WITH ONLY SOME
LINGERING LIGHT SNOW POSSIBLE ON CHRISTMAS EVE DAY. TEMPERATURES
WILL REMAIN IN THE MID 30S. CHRISTMAS DAY WILL BE DRY WITH LITTLE
CHANGE IN TEMPERATURE AS A BROAD SURFACE RIDGE SLIDES ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY.
SNOW CHANCES INCREASE THURSDAY NIGHT THROUGH FRIDAY AS THE NEXT
TROUGH CARVES ITS WAY ACROSS THE WESTERN CONUS. SURFACE LOW TRACK
IS SIMILAR BETWEEN THE 22.12Z GFS/ECMWF/GEM...BUT PRECIPITATION
PLACEMENT DIFFERS BETWEEN THE DRIER ECMWF AND WETTER GFS/GEM. FOR
NOW...WILL FOLLOW SUPERBLEND GUIDANCE AND BROAD BRUSH CHANCE POPS
ACROSS THE FORECAST AREA.
AFTER A COLD FRONT SWEEPS ACROSS THE REGION FRIDAY NIGHT...THE
UPCOMING WEEKEND LOOKS DRY BUT COLDER WITH DAILY HIGH TEMPERATURES
IN THE 20S AND NIGHTTIME LOWS MAINLY IN THE TEENS. THERE IS A
SLIGHT CHANCE FOR SNOW SUNDAY NIGHT INTO MONDAY...BUT GIVEN VAST
MODEL DIFFERENCES...WILL KEEP 20 POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1129 PM CST MON DEC 22 2014
MVFR/IFR CONDITIONS TO PERSIST INTO TUESDAY AS A LOW PRESSURE
SYSTEM LIFTS UP INTO THE REGION. THE MAIN QUESTION WILL BE WITH
PRECIPITATION TYPE AS TEMPERATURES ARE RIGHT AROUND FREEZING. LSE
HAS A HIGHER CHANCE OF BEING MORE RAIN THAN RST...BUT COULD EASILY
CHANGE OVER ON TUESDAY MORNING. LOW CONDITIONS WILL LIKELY HANG ON
THROUGH TUESDAY NIGHT AND POSSIBLY INTO WEDNESDAY. WINDS WILL BE
SHIFTING FROM THE NORTHEAST TO THE NORTHWEST ON TUESDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
356 AM CST THU DEC 25 2014
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/06Z
ISSUED AT 1133 PM CST WED DEC 24 2014
HIGH PRESSURE RIDGE OVER IA WILL MOVE TO THE EAST. IFR CONDITIONS
WILL IMPROVE FROM THE WEST AFTER RIDGE PASSAGE WITH CIGS LIFTING
TO VFR AFTER 12Z. VFR CONDITIONS WILL PREVAIL THROUGH CHRISTMAS
DAY INTO THE EVENING.
OUTLOOK...DETERIORATING CONDITIONS FROM THE NORTHWEST AS THE NEXT
FRONTAL SYSTEM APPROACHES FRIDAY. IFR AND MVFR WILL SPREAD INTO
NWRN IA DURING THE DAY...AND OVER THE TAF SITES FRIDAY NIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...MS DEC 14
AREA FORECAST DISCUSSION
NWS JACKSON KY
326 AM EST THU DEC 25 2014
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 130 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH WORKS ACROSS THE REGION AND LOW LEVEL
MOISTURE REMAINS...AND DRIZZLE AND SOME ISOLATED SHOWERS ALONG WITH
CIGS IN THE MVFR/FUEL ALTERNATE RANGE WILL LINGER THROUGH ABOUT
12Z. ANY LINGERING LIGHT PRECIP SHOULD END BETWEEN 12Z AND 18Z. MVFR
CIGS SHOULD LINGER AS LONG AS 18Z OR LATER IN THE EAST...BUT AS
RIDGING BUILDS INTO THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO
EAST. WINDS WILL REMAIN SOUTHWEST TO WEST SOUTHWEST FOR THE FIRST 12
HOURS OF THE PERIOD AND THEN BECOME LIGHT AND VARIABLE AS THE CENTER
OF HIGH PRESSURE NEARS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1109 PM EST WED DEC 24 2014
.SYNOPSIS...
STRENGTHENING LOW PRESSURE WILL LIFT INTO THE GREAT LAKES
TONIGHT...BRINGING A COLD FRONT ACROSS THE REGION. MILD SOUTHERN
HIGH PRESSURE WILL MOVE IN FOR THE END OF THE WEEK. A WEAK COLD
FRONT WILL PUSH IN FROM THE NORTHWEST SUNDAY. THEN...LOW PRESSURE
FROM THE DEEP SOUTH WILL RIDE UP ALONG THAT FRONT AND OVER THE
REGION EARLY NEXT WEEK. COLDER HIGH PRESSURE WILL FOLLOW FOR MID
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
1109PM UPDATE...DENSE FOG ADVISORY CANCELLED.
02Z WATER VAPOR IMAGERY INDICATING CENTER OF SFC LOW PIVOTING
THROUGH GREAT LAKES REGION...WITH ASSOCIATED COLD FRONT EXTENDING
SOUTH OVER WESTERN PA/CENTRAL WV. WARM FRONT SITUATED TO THE EAST
NOW...TAKING THE LIGHT RAIN WITH IT. MOIST AIRMASS IN PLACE HAS
RESULTED IN WIDESPREAD FOG WITH AREAS OF DENSE FOG MAINLY EAST OF
BLUE RIDGE. CONTINUING DENSE FOG ADV HERE TO ACCOUNT FOR VIS BEING
REDUCED TO 1/4 MILE OR LESS. AS THE PCPN MOVES IN...ENOUGH MIXING
SHOULD OCCUR TO IMPROVE VIS TO AT LEAST A MILE OR MORE.
A LINE OF SHOWERS WITH EMBEDDED HEAVIER SHOWERS NOTED RIGHT ALONG
THE COLD FRONT. ISO SVR TSTMS HAD BEEN OBSERVED IN THE LINE
EARLIER THIS EVENING...BUT WITH LOSS OF ANY INSTABILITY...WHICH
WAS MINIMAL TO BEGIN...NOT ANTICIPATING ANY THUNDER TO EXTEND INTO
OUR CWA. MATCHING WITH LATEST HRRR RUN AND TIMING OF THE
RADAR...STEP THE PCPN ACROSS DURING THE OVERNIGHT HOURS. HRRR ALSO
SUGGESTIVE OF A BIG WAVE OF PCPN COMING UP FROM THE SOUTH AHEAD OF
THIS LINE. WITH THE MOISTURE IN PLACE AND DECENT FORCING ALOFT NOT
QUESTIONING THE FORMATION OF THESE SHOWERS...JUST THE
INTENSITY/COVERAGE. AS SUCH...KEPT LIGHT SHOWER MENTION...WITH THE
PCPN TAPERING OFF FROM THE WEST THROUGH THE DAYLIGHT HOURS.
EXPECTING ALL PCPN TO HAVE CLEARED THE AREA BY 12Z.
ANOTHER CONCERN FOR THE NIGHT IS A WIND ADVISORY IN PLACE FOR THE
POTOMAC HIGHLANDS. STRONG LLJ EXPECTED TO MOVE WITH WINDS AT 850MB
45-55 KTS. WITH THE HIGHER ELEVATIONS...COULD SEE SOME OF THESE
STRONGER WINDS IMPACT THE AREA. WOULD ALSO LIKE TO NOTE THE
HEAVIER SHOWERS MOVING THROUGH WITH THE COLD FRONT COULD BRING
DOWN HEAVIER GUSTS. RIGHT NOW THE ADVISORY GOES THROUGH 11Z...BUT
COULD VERY WELL SEE IT END SOONER WITH THE STRONGEST LLJ WINDS
LOOKING TO MOVE THROUGH THAT AREA BY 08Z.
BREEZY CONDS WL RESIDE BHD CDFNT...W/ BETTER MIXING IN PLACE. SOURCE
RGN OF AMS NOT THAT COLD...AND WL HV DOWNSLOPING WNDS. THEREFORE...MAXT
TMRW SHUD BE SIMLR TO TDA...OR PERHAPS A PINCH WARMER. MRNG CLDS
FM PVA WL QUICKLY ERODE. MOSUN FOR THE REST OF THE DAY.
UPSLOPE CONDS GOOD FOR CONTD CLDCVR ALONG THE WRN SLOPES...BUT LACK
OF MSTR NOT FVRBL FOR PRODUCING PCPN. MTN POPS THU STILL CAPPED AT
CHC...AND HV PTYPE MIX RA/SN.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AFTER THE MULTI-DAY PERIOD OF INFLUENCE FROM ANOTHER MONSTROUSLY
LARGE LOW PRESSURE SYSTEM...BY THURS NIGHT - WE WILL BE ON THE CUSP
OF A MULTI-DAY REPRIEVE...AT LEAST A COUPLE OF DAYS. IN THE WAKE OF
THE EXITING LOW...SFC HIGH PRESSURE WILL BUILD IN TO OUR SOUTH...
WHICH IS AN IMPORTANT KEY BECAUSE IT WILL SPREAD WARMER TEMPS UP THE
ERN SEABOARD INTO THE WEEKEND. FRIDAY WILL BE CLEAR AND QUIET. AFTER
A BREEZY/WINDY THURSDAY...WINDS WILL DROP OFF TO A LIGHT SLY FLOW.
ALTHOUGH NOT AN INCREDIBLY WARM DAY...MAX TEMPS ON FRI SHOULD REACH
5-10F ABOVE AVG FOR LATE DEC.
WHILE THE HIGH ROLLS OFF THE CAROLINA COAST INTO SATURDAY...SLY FLOW
WILL AGAIN BRING IN SLIGHTLY WARMER AIR W/ MAX TEMPS A BIT HIGHER
THAN FRIDAY...TOPPING OUT IN THE M-U50S. ANOTHER LOW PRESSURE WAVE
WILL SET UP OVER THE SRN PLAINS/LOWER MS VLY. GULF COAST MOISTURE
WILL AGAIN BE TAPPED FOR THE EARLY STAGES OF THIS NEXT SYSTEM...BUT
IN TERMS OF NORTHWARD EXTENT - IT WILL HAVE TROUBLE W/ SECONDARY
WAVES COMING IN FROM THE NW. 12Z RUNS OF THE GFS/EURO ARE IN THE
CLOSEST ALIGNMENT W/ EACH OTHER IN THE PAST FEW DAYS AS TO THE
INTERACTIONS/PROGRESSIONS OF THESE FEATURES. A STRONG ENOUGH UPPER
JET WILL TRANSPORT THE SHEARED EDGE OF THE GULF MOISTURE UP ACROSS
THE UPPER MIDWEST LATE SAT NIGHT. HOWEVER...A POTENT UPPER LOW
SLIDING JUST SOUTH OF HUDSON BAY WILL TAKE THIS NRN MOISTURE UP AND
OVER THE REGION BEFORE THE SRN SYSTEM CAN GET FULLY ORGANIZED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL HANG ON INTO
SATURDAY NIGHT. DRY CONDITIONS WILL LINGER. THERE IS A CHANCE FOR
A FEW UPSLOPE SNOW SHOWERS IN THE HIGHER PARTS OF THE POTOMAC
HIGHLANDS. JUST TWENTY FOUR HOURS AGO...THE EURO AND GFS MODELS
WERE BOTH HINTING OF A COLD FRONTAL PASSAGE SATURDAY INTO SATURDAY
NIGHT. SINCE THEN...BOTH MODELS HAVE BACKED OFF ON THIS IDEA.
THE COLD FRONT SHOULD PUSH ACROSS THE AREA SUNDAY BEFORE SLIDING TO
THE SOUTH AND STALLING ACROSS THE CAROLINAS BY SUNDAY NIGHT. SOME
LIGHT STRATIFORM RAIN WILL ACCOMPANY THE FRONT SUNDAY AND INTO
MONDAY WITH THE FRONT JUST TO OUR SOUTH. THE 00Z EURO MODEL STILLS
WANTS TO HANG ONTO THE IDEA OF A LOW DEVELOPING ALONG THE STALLED
FRONT BUT NOW THE GFS JUST WANTS TO PUSH ELONGATED STRANDS OF ENERGY
ALONG THE SURFACE FRONT AND OUT TO SEA. CONSIDER THIS...HIGH
UNCERTAINTY ON WHETHER WE SEE ADDITIONAL PERIODS OF LIGHT RAIN OR
PERHAPS LIGHT SNOW IN OUR CWA BY MONDAY NIGHT.
THERE IS A SLIGHT CHANCE OF SOME DEPARTING RAIN OR SNOW SHOWERS
TUESDAY...SHOULD A LOW DEVELOP ALONG THE FRONT. OTHERWISE...DRY
CONDITIONS WILL BE BROUGHT ABOUT WITH HIGH PRESSURE BUILDING LATER
TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
IFR OR LOWER CONDITIONS THIS EVENING AHEAD OF APPROACHING FRONT.
LIFR CIGS ACROSS THE AREA THRU AT LEAST 05Z. CURRENTLY HAVE CIGS
IMPROVING TO IFR OR MVFR AS THE FRONT/SHOWERS MOVE THRU.
HOWEVER...IMPROVEMENT TIME COULD BE 2-3 HOURS LATER THAN IN TAF.
NOT EXPECTING VFR TILL LATE TONIGHT. LOW CONFIDENCE ON TIMING OF CIGS.
VIS VARYING FROM LESS THAN 1 MILE TO 3 MILES ACROSS THE TAF
SITES. WILL KEEP VIS DOWN THROUGH THE NIGHT TILL FROPA...IMPROVING
TO P6SM LATE TONIGHT. THE 1 MILE OR LESS COULD CONTINUE 1-2 HOURS
LATER THAN IN TAF.
HIGHEST CONFIDENCE IN FORECAST IS WINDS...SLY FLOW THIS
EVENING...BCMG SW THEN W OVERNIGHT WITH FROPA. PSBL OCNL GUSTS
WITH W FLOW LATE TONIGHT...THEN MORE PERSISTENT GUSTS 20-25 KTS
DURING THE DAY TOMORROW. VFR CONDITIONS AS WELL THRU THE DAY WITH
SCT CU.
HIGH PRESSURE BUILDS IN AS THE POTENT LOW PRESSURE SYSTEM MOVES OFF
THE COAST LATE THU. THE HIGH WILL KEEP CONDITIONS QUIET/SOLID VFR
INTO THE WEEKEND.
&&
.MARINE...
WINDS SLOW TO INCREASE THIS EVENING ON THE WATERS WITH QUITE A
STABLE AIRMASS IN PLACE. OCNL GUSTS TO 17-18 KTS MAINLY OVER THE
SOUTHERN WATERS...BUT OTHERWISE...NOT QUITE AT SCA YET.
HOWEVER...EXPECTING A STRONG LLJ TO MOVE OVER THE WATERS THROUGH
THE OVERNIGHT...WHICH COULD SEE ENOUGH ENERGY MIX DOWN TO RESULT
IN GUSTS TO 20 KTS. HIGHER CONFIDENCE OF SCA EXISTS THOUGH IN THE
WAKE OF THE COLD FRONT THURS.
CDFNT E OF WATERS BY THU. WHILE GLW CONDS NOT OUT OF THE QSTN...IT
WUD TAKE IDEAL MIXING. STICKING W/ MEAN MIXED LYR...AND CARRYING SCA
THRU THE DAY.
LIGHT WINDS TO CLOSE OUT THE WEEK AS A LARGE SFC HIGH DEVELOPS TO
OUR SOUTH AND CALMS DOWN THE AREA WIND FIELD. SLY CHANNELING
POSSIBLE INTO LATE SAT W/ THE HIGH MOVING OFF THE COAST AND ANOTHER
LOW PRESSURE SYSTEM APPROACHING FROM THE WEST.
&&
.TIDES/COASTAL FLOODING...
TIME OF HIGH TIDE HAS PASSED FOR LOWER CHESAPEAKER BAY WITH WATER
LEVELS SLOWLY COMING DOWN NOW. AS OF 7 PM...LEVELS BELOW ANY
FLOODING THRESHOLDS SO ALLOWED THE ADV TO EXPIRE THERE. CONTINUING
NORTHERN CHESAPEAKE BAY WESTERN SHORE AS ANNAPOLIS CURRENTLY
SHOWING IN SOLID MINOR LVLS...AND THE REMAINING AREAS EXPECTING TO
REACH MINOR LVLS WITH 1.5 FT ANOM PSBL.
A COLD FRONT CROSSES THE WATER TONIGHT. DIRECTION NOT ALL THAT
GREAT FOR BLOWOUT CONDITIONS. WE WILL NEED TO SEE HOW MUCH WATER
IS TRULY PUSHED OUT. MAY NEED AN ADVISORY FOR ANOTHR CYCLE...ESPECIALLY
MID BAY. ON THE FLIP SIDE...THE AM CYCLE IS THE LOWER OF THE TWO
ASTRONOMICALLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MDZ501.
COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ011-
014-508.
VA...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ503-504.
WV...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ501>503-505-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ530>543.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1133 PM CST Wed Dec 24 2014
.UPDATE:
Issued at 831 PM CST Wed Dec 24 2014
Already updated the fcst once this evng to account for the
lingering precip across the area and it looks like another update
will be necessary as the pesky light rain and drizzle will be slow
to exit the area. The precip has slowly been transitioning from
measurable to trace over the past several hrs. So that will be
the flavor thru midnight...lingering patchy drizzle. Temps have
also been slow to fall off and have been holding steady so far
this evng despite the CAA. Still think lows for tonight look good
with upstream obs across wrn MO in the low 30s. All other elements
look reasonable with only minor adjustments to account for short
term trends. A new update will be out shortly.
2%
&&
.SHORT TERM: (Through Tonight)
Issued at 325 PM CST Wed Dec 24 2014
An area of light rain possibly mixed with a few wet snowflakes
currently centered through St. Louis was moving east around 25-30
kts. This precipitation is occurring in association with a trailing
vort max within the cyclonic flow on the backside of the exiting
upper trof. Present indications are it should have exited or just
about exited the eastern CWA counties in south central/southwest IL
at 00z. There might be some lingering patchy drizzle for a few hours
into early evening. Satellite imagery has stratus hanging tough and
still well back into eastern KS and eastern OK at 21z. Trends along
with the RAP and NAM 925 mb RH suggests the clearing trend will be
slow and won`t commence in our CWA until well after midnight, and
the back edge of clouds around 50 miles west of STL at 12z Thursday.
The clouds will help keep temperatures a tad warmer overnight than
the previous forecast.
Glass
.LONG TERM: (Thursday through Next Wednesday)
Issued at 325 PM CST Wed Dec 24 2014
(Thursday through Saturday)
Primary focus thru this period will be precip chances late in the
period.
Mdls remain in good agreement thru Fri. Sfc winds quickly become sly
by tomorrow as ridge quickly moves off to the E. Expect current
cloud deck to move ewd tonight and shud be along/near the MS River
around 12z Thurs. These clouds shud be on the ern boarder of the CWA
by 18z. However, mdls suggest these low clouds will probably be
replaced with CI which shud hinder heating somewhat. Have therefore
kept temps twd the cooler guidance, esp across ern portions of the
CWA will clouds will linger. For Fri, have trended slightly warmer
as strong sly winds will be in place. However, with questions
regarding cloud cover, did not go as high as warmer MOS for now.
Cut off low over srn Rockies begins to open and eject into the
Plains by Fri evening. However, the GEM is a slower soln and
actually redevelops an upper low after the initial s/w is reaching
the nrn Plains. As this soln is an outlier, have trended away from
this soln and twd the other mdls which remain in good agreement.
Have kept PoPs in lower chance category for now as mdl soundings
suggest much of the QPF may be more DZ than RA. Not to mention that
the NAM and local WRF suggest the precip bifurcating with a branch
to the N and one to the S. However, with the trof approaching and
some low level forcing, light RA will be possible. Question becomes
p-types on Sat and Sat night as the cold air filters into the
region. While the GFS soundings suggest precip will end as a brief
period of IP, then SN, setup is typical of this area where precip
will likely end as RA just ahead of the surge of cold air. This is
more likely given the sfc ridge center is currently progd to be over
wrn KS. Regardless, close attention shud be paid to this time period
as mdls come into better agreement.
(Sunday through Wednesday)
Focus quickly turns to temps thru this period.
Will continue trends twd a GFS/ECMWF compromise due to issues with
the GEM mentioned above. The DGEX also becomes a fast outlier as the
next trof ejects into the Plains sometime on Wed.
Relatively cold air moves in place behind the cdfnt on Sat. A
secondary cdfnt is expected to push thru the region Sun night into
Mon ahead of the next system approaching the region late Mon night
into Wed. Have trended temps twd cooler guidance for Tues and beyond
placing temps nearly 20 degrees below seasonal avg.
A number of questions arise with the system on Tues/Wed. The GFS
cuts off an upper low over the swrn U.S. which it is known to do.
The ECMWF ejects this trof into the Plains, but given the weakening
jet upstream of this trof, am not convinced this soln is correct.
With both mdls suggesting very low QPF, will keep only slight chance
PoPs going for now with plenty of time to adjust. The one item both
mdls do agree on is the precip is expected to be all SN.
Tilly
&&
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Dec 24 2014
Back edge of SC deck is making its way east across western MO as
of 0530z. KCOU should begin to scatter out around 08z Thursday,
while KUIN and metro area tafs should scatter out between 11z-12z
Thursday. Otherwise, west winds to back to the south by daybreak
and pickup by mid morning to between 10 and 15kts and remain that
way through rest of forecast period.
Specifics for KSTL:
Back edge of SC deck is making its way east across western MO as
of 0530z. Metro area should scatter out between 11z-12z Thursday.
Otherwise, west winds to back to the south by 12z and pickup
by 18z to between 10 and 15kts and remain that way through
rest of forecast period.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
404 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1133 PM CST WED DEC 24 2014
FOR THE KLBF TERMINAL...EXPECT BROKEN HIGH CLOUDS RANGING FROM
15000 TO 20000 FT AGL THROUGH 21Z THURSDAY. CIGS WILL LOWER TO
MVFR AFTER 21Z THURSDAY WITH CIGS RANGING FROM 800 TO 1500 FT AGL
BY EVENING. THERE IS A SMALL THREAT FOR SNOW THURSDAY EVENING AND
IT WILL BE HANDLED WITH A PROB 30 GROUP ATTM. FOR THE KVTN
TERMINAL...EXPECT HIGH CLOUDS OVERNIGHT WITH CIGS LOWERING TO 5000
TO 10000 FT AGL THURSDAY MORNING. CIGS WILL LOWER TO 1500 FT AGL
BY EARLY AFTERNOON. LIGHT SNOW IS EXPECTED TO DEVELOP AFTER 21Z
WITH CIGS AROUND 1200 FT AGL AND VISBYS AS LOW AS 2 SM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON CST /11 AM MST/ TODAY TO NOON
CST /11 AM MST/ FRIDAY FOR NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
230 AM EST THU DEC 25 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
800 PM EST UPDATE..
UPDATED WIND ADVISORY... WIND ADVISORY NOW IN EFFECT STARTING 1 AM
EST...
RAIN SHOWERS HAVE PRETTY MUCH EXITED THE REGION TO THE EAST AND WE
SHOULD REMAIN IN A LULL FOR THE NEXT FEW HOURS. A COLD FRONT WILL
SURGE ACROSS THE REGION AFTER MIDNIGHT TONIGHT BRINGING AN
ADDITIONAL SHOT OF RAIN SHOWERS. A FEW RUMBLES OF THUNDER WILL BE
POSSIBLE AS THE FROPA MOVES EAST. WE ARE STILL EXPECTING STRONG
WINDS WITH THIS FRONT AND IS MOVING SLIGHTLY MORE QUICKLY THAN
EXPECTED.
COLD FRONT IS ADVANCING QUICKLY TO THE EAST AND IS JUST
CROSSING INTO WESTERN PENNSYLVANIA. EXPECT THIS FRONT TO START TO
IMPACT THE CWA AROUND 06Z IN THE FAR WESTERN EDGES... THUS CHANGED
THE START TIME OF THE WIND ADVISORY FROM 5 TO 1AM. HIGH WINDS WILL
QUICKLY SPREAD EAST DURING THE EARLY MORNING HOURS ON THURS.
LOOKING AT FORECAST SOUNDINGS AND CURRENT OBSERVATIONS... BELIEVE
GUSTS SHOULD REMAIN BELOW 45 KNOTS ACROSS THE CWA WHEN THE FRONT
PASSES THROUGH... DECIDED TO NOT UPGRADE TO A WARNING. WINDS ARE
EXPECTED TO REMAIN STRONG THROUGH MUCH OF DAY TOMORROW. FOR MORE
INFORMATION PLEASE READ PREVIOUS DISCUSSION BELOW.
PREVIOUS FORECAST...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB
WIND FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR
AREA. ONCE THIS LIFTS NE OF THE REGION LATER THIS
AFTERNOON...THERE WILL BE A LULL IN THE PRECIP UNTIL THE COLD
FRONT WHICH WAS PRESENTLY EXTENDED FROM SERN LWR MI TO FAR WRN OH
TO CNTRL KY RACES EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE
THAT WILL PASS THRU THE REGION LATER TONIGHT. THIS FEATURE WILL BE
THE IMPETUS TO FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY
AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRF-NMM AND WRF-ARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
230 AM UPDATE...
AFTER FRONT MVS THRU AREA BY 12Z SUNDAY, PATTERN BCMS MAINLY ZONAL
THRU END OF THE EXTNDD. CANADIAN HIPRES EXPECTED TO DOMINATE WITH
OCNL LK PCPN AND CLDS FILTERING DOWN ON NRLY FLOW. AIRMASS WL BCM
INCREASINGLY COLD THRU THE MIDDLE PART OF THE WEEK. NO MAJOR CHGS
ANTICIPATED TO LONG TERM GRIDS THIS MRNG.
PREV DISCUSSION BLO...
GFS/ECMWF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FORECAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON- DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
AREA OF SHOWERS WITH STRONG WIND SHIFT WILL BE AT ELM AND ITH AT
START OF TAF VALID TIME THEN QUICKLY MOVING INTO RME AND AVP BY
07Z. MVFR RESTRICTIONS AS SHOWERS MOVE THROUGH THE AREA TONIGHT.
BEHIND THESE SHOWERS EXPECT TERMINALS WILL STAY MVFR CIGS THROUGH
THE COURSE OF THE DAY BEFORE BECOMING VFR AFTER 20Z FOR ALL SITES
WITH EXCEPTION OF RME. RME SHOULD REMAIN MVFR THROUGH END OF TAF
VALID TIME.
FOR A BRIEF HOUR TONIGHT, EXPECT LLWS AT RME, SYR, BGM AND AVP.
WINDS WILL QUICKLY SHIFT AROUND TO THE SW BY 07Z TONIGHT AT ALL
TERMINALS WITH 15-20KTS SUSTAINED, GUSTING TO 30-35KTS AT TIMES.
OUTLOOK...
FRI/SAT...VFR.
LATE SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-
SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ009-015>018-
022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/KAH
SHORT TERM...DJN
LONG TERM...MSE/PVF
AVIATION...PVF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1243 AM EST THU DEC 25 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
800 PM EST UPDATE..
UPDATED WIND ADVISORY... WIND ADVISORY NOW IN EFFECT STARTING 1 AM
EST...
RAIN SHOWERS HAVE PRETTY MUCH EXITED THE REGION TO THE EAST AND WE
SHOULD REMAIN IN A LULL FOR THE NEXT FEW HOURS. A COLD FRONT WILL
SURGE ACROSS THE REGION AFTER MIDNIGHT TONIGHT BRINGING AN
ADDITIONAL SHOT OF RAIN SHOWERS. A FEW RUMBLES OF THUNDER WILL BE
POSSIBLE AS THE FROPA MOVES EAST. WE ARE STILL EXPECTING STRONG
WINDS WITH THIS FRONT AND IS MOVING SLIGHTLY MORE QUICKLY THAN
EXPECTED.
COLD FRONT IS ADVANCING QUICKLY TO THE EAST AND IS JUST
CROSSING INTO WESTERN PENNSYLVANIA. EXPECT THIS FRONT TO START TO
IMPACT THE CWA AROUND 06Z IN THE FAR WESTERN EDGES... THUS CHANGED
THE START TIME OF THE WIND ADVISORY FROM 5 TO 1AM. HIGH WINDS WILL
QUICKLY SPREAD EAST DURING THE EARLY MORNING HOURS ON THURS.
LOOKING AT FORECAST SOUNDINGS AND CURRENT OBSERVATIONS... BELIEVE
GUSTS SHOULD REMAIN BELOW 45 KNOTS ACROSS THE CWA WHEN THE FRONT
PASSES THROUGH... DECIDED TO NOT UPGRADE TO A WARNING. WINDS ARE
EXPECTED TO REMAIN STRONG THROUGH MUCH OF DAY TOMORROW. FOR MORE
INFORMATION PLEASE READ PREVIOUS DISCUSSION BELOW.
PREVIOUS FORECAST...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB
WIND FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR
AREA. ONCE THIS LIFTS NE OF THE REGION LATER THIS
AFTERNOON...THERE WILL BE A LULL IN THE PRECIP UNTIL THE COLD
FRONT WHICH WAS PRESENTLY EXTENDED FROM SERN LWR MI TO FAR WRN OH
TO CNTRL KY RACES EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE
THAT WILL PASS THRU THE REGION LATER TONIGHT. THIS FEATURE WILL BE
THE IMPETUS TO FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY
AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRF-NMM AND WRF-ARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECMWF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FORECAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON-DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
AREA OF SHOWERS WITH STRONG WIND SHIFT WILL BE AT ELM AND ITH AT
START OF TAF VALID TIME THEN QUICKLY MOVING INTO RME AND AVP BY
07Z. MVFR RESTRICTIONS AS SHOWERS MOVE THROUGH THE AREA TONIGHT.
BEHIND THESE SHOWERS EXPECT TERMINALS WILL STAY MVFR CIGS THROUGH
THE COURSE OF THE DAY BEFORE BECOMING VFR AFTER 20Z FOR ALL SITES
WITH EXCEPTION OF RME. RME SHOULD REMAIN MVFR THROUGH END OF TAF
VALID TIME.
FOR A BRIEF HOUR TONIGHT, EXPECT LLWS AT RME, SYR, BGM AND AVP.
WINDS WILL QUICKLY SHIFT AROUND TO THE SW BY 07Z TONIGHT AT ALL
TERMINALS WITH 15-20KTS SUSTAINED, GUSTING TO 30-35KTS AT TIMES.
OUTLOOK...
FRI/SAT...VFR.
LATE SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-
SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ009-015>018-
022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/KAH
SHORT TERM...DJN
LONG TERM...JAB/MSE/TAC
AVIATION...PVF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1236 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE OFFSHORE BEFORE DAYBREAK THIS MORNING.
SUNSHINE IS EXPECTED TO MAKE A RETURN THIS AFTERNOON AS DRY HIGH
PRESSURE BUILDS INTO THE CAROLINAS TODAY AND FRIDAY...MOVING
OFFSHORE SATURDAY. A COLD FRONT WILL DROP INTO THE SOUTHEAST ON
SUNDAY WITH AREAS OF LOW PRESSURE DEVELOPING MONDAY THROUGH
WEDNESDAY NEXT WEEK...RESULTING IN UNSETTLED WEATHER ACROSS THE
CAROLINAS.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1230 AM THURSDAY...COLD FRONT WILL CROSS THE INTERSTATE 95
CORRIDOR BETWEEN 1 AND 2 AM...AND SHOULD REACH THE COAST BETWEEN 3-5
AM. AN ABRUPT WIND SHIFT IS EXPECTED WITH THE FRONT ALONG WITH COLD
ADVECTION WHICH WILL CONTINUE THROUGH THE DAYLIGHT HOURS LATER
TODAY. CHANGES WITH THIS NEAR-TERM UPDATE FOCUS ON PRECIP COVERAGE
WITH THE FRONT AND HOURLY TEMPERATURES/DEWPOINTS/WINDS. PREVIOUS
DISCUSSION FROM 1000 PM FOLLOWS...
THERE IS NO LONGER A SEVERE WX THREAT ACROSS THE ILM CWA. THE BEST
ORGANIZED CONVECTION IS NOW OVER THE OFFSHORE WATERS PARALLELING THE
CAROLINA COASTLINES FROM OFF CAPE LOOKOUT SOUTHWARD TO OFF CAPE
ROMAIN. THIS ACTIVITY CONTINUES TO PULL FURTHER AWAY FROM THE U.S.
MAINLAND. THIS UPDATE WILL CONCENTRATE ON EVEN FURTHER LOWERING POPS
FROM WEST TO EAST THRUOUT THE REMAINDER OF THE EVENING AND OVERNIGHT
PERIOD. THE COLD FRONT REMAINS SLATED TO PUSH FROM WSW TO ENE ACROSS
THE ILM CWA AND OFF THE COAST DURING THE LATE EVENING HRS THRU THE
PRE-DAWN THU HOURS. LATEST HRRR INDICATES A THIN BAND OF POST
FRONTAL -SHRA TO OCCUR ACROSS THE FA...AND WILL LEAVE IN A LOW
CHANCE POP CHANCE UP TO AROUND OR JUST AFTER DAYBREAK THU. HAVE
RE-TWEAKED HOURLY SFC TEMPS AND DEWPOINTS TO ACCOUNT FOR THE LATEST
TRENDS. HAVE KEPT MORNING MINS BASICALLY THE SAME FROM THE PREVIOUS
730 PM UPDATE. THE LOWS WILL LIKELY OCCUR AT OR 1-2 HRS AFTER
DAYBREAK THU.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 334 PM WEDNESDAY...MAIN WEATHER HEADLINE IS THAT SUNSHINE IS
SLATED TO MAKE A DEBUT CHRISTMAS DAY AS SHARP DRYING FOLLOWS A
COLD FRONT SWEEPING OUT TO SEA BY DAYBREAK THURSDAY. HIGH PRESSURE
OF GULF COAST ORIGIN WILL RESULT IN WEAK COOL AIR ADVECTION AND
MAXIMUMS WILL REBOUND SLIGHT ABOVE NORMAL THURSDAY AND FRIDAY FOR
LATE DECEMBER. FRIDAY DAYBREAK LIKELY THE COLDEST TEMPS THIS
PERIOD WITH 30S WIDESPREAD ACROSS THE AREA...CLIMBING 25-28
DEGREES F BY AFTERNOON INTO THE LOW AND MIDDLE 60S UNDER SUNSHINE
AND A FEW STRANDS OF CIRRUS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM WEDNESDAY...BEGINNING OF THE WEEKEND PLEASANT BUT
HEIGHT FALLS AND AN APPROACHING COLD FRONT INTO SUNDAY WILL BRING
CLOUDS AND AN INCREASING CHANCE OF RAIN INTO SUNDAY NIGHT.
INDICATIONS ARE THE FRONT MAY STALL OVER OR NEAR THE FORECAST AREA
MONDAY THROUGH MID-WEEK...ALLOWING FOR UNSETTLED WEATHER AS A
SERIES OF WAVES TRAVEL ALONG THE STALLED BOUNDARY. BY DAYS 6/7
TUESDAY AND WEDNESDAY...A COLD FRONT LOOKS TO BRING COOLING AND
UNDERCUTS THE SW FLOW ALOFT. THIS MAY LEAD TO MURKY CONDITIONS
AND MULTIPLE CHANCES OF RAIN/SHOWERS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...A COLD FRONT MOVING EASTWARD WILL REACH FLO AROUND
0600Z...LBT AROUND 0700Z...MYR AND CRE AROUND 0800Z...AND ILM AROUND
0930Z. SOME LOW CLOUDS CONTINUE TO AFFECT THE COAST WITH CEILINGS
POTENTIALLY BELOW 1000 FEET AT CRE AND ILM FOR THE NEXT COUPLE OF
HOURS. THIS THREAT SHOULD END WITH THE FRONTAL PASSAGE. EXPECT SW
WINDS TO TURN WEST WITH AN HOUR OR TWO OF GUSTS TO 20 KT AS COLDER
AIR PUNCHES IN BEHIND THE FRONT. MAINLY LIGHT SHOWERS NEAR THE
BOUNDARY SHOULD CLEAR OUT WITHIN 1 HR OF THE FRONTAL PASSAGE.
BY DAYBREAK A MID-LEVEL CLOUD CEILING WILL REMAIN...BUT EVEN THIS
SHOULD PUSH OFFSHORE BY LATE MORNING OR EARLY AFTERNOON WITH VFR
CONDITIONS EXPECTED.
EXTENDED OUTLOOK...VFR THURSDAY THROUGH SATURDAY. RAIN RETURNING
SUNDAY AND POSSIBLY MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM THURSDAY...CHANGES TO THE NEAR-TERM PORTION OF THE
COASTAL WATERS FORECAST FOCUS ON THE COLD FRONT WHICH WILL REACH THE
SC COAST AROUND 3 AM...AND THE NC COAST BETWEEN 330 AM AND 500 AM.
AS THE FRONT ITSELF MOVES ACROSS WINDS WILL ABRUPTLY SHIFT FROM SW
TO W WITH GUSTS POTENTIALLY REACHING 30 KNOTS. OTHER FORECAST
ELEMENTS REMAIN LARGELY UNCHANGED. PREVIOUS DISCUSSION FROM 1000 PM
FOLLOWS...
BASED ON LATEST BUOY OBS...WINDS AND SEAS TRENDS ACROSS THE ILM
WATERS HAVE BASICALLY PEAKED DURING THE AFTERNOON HRS...AND ARE NOW
HOLDING MORE OR LESS STEADY. DO EXPECT ANOTHER TEMPORARY INCREASE IN
WINDS AND RESULTANT SEAS DURING THE PRE-DAWN THU HRS...LEADING UP TO
A FEW HRS AFTER DAYBREAK. BASICALLY JUST AHEAD AND IMMEDIATELY AFTER
THE CFP. AS FOR ACTUAL WIND DIRECTIONS AND SPEEDS...WIND DIRECTIONS
WILL VEER FROM THE CURRENT SW DIRECTION...TO WESTERLY LATE TONIGHT
INTO DAYLIGHT THU. A TIGHTENED SFC PG WILL YIELD SPEEDS BETWEEN 15
TO 25 KT...WITH A FEW GUSTS TO 30 KT POSSIBLE LEADING UP TO AND JUST
AFTER THE CFP. SIGNIFICANT SEAS WILL HOLD RELATIVELY STEADY IN THE 5
TO 8 FT RANGE OVERNIGHT...HIGHEST ACROSS THE LOCAL WATERS BETWEEN
CAPE FEAR TO LITTLE RIVER INLET. AVERAGE PERIODS WILL RUN 5.0 TO 6.0
SECONDS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 PM WEDNESDAY...MODERATE WINDS THURSDAY WILL EASE AND
TURN NW LATER IN THE DAY. RESIDUAL WAVE ENERGY WILL TAKE MORNING
TO SETTLE AND RECOVER...AND THE ADVISORY MAY NEED TO RUN THROUGH
MOST IF NOT ALL OF MORNING. THURSDAY ANY STORMS WILL BE CONFINED
TO THE GULF STREAM AND POINTS FARTHER TO SEA. LIGHT WINDS FRIDAY
AND PLEASANT AS SURFACE HIGH PRESSURE MOVES NEARLY OVERHEAD OR JUST
NORTH OF THE AREA. WINDS FRIDAY 10 KT OR LESS FROM NE-ESE.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 330 PM WEDNESDAY...SATURDAY FEATURES A SURFACE HIGH
MIGRATING OFFSHORE AND WEAK RETURN WINDS FROM THE S. A COLD FRONT
WILL DROP FROM THE N VERY LATE IN THE PERIOD MONDAY NIGHT AND
BRING INCREASING NE WINDS...ALTHOUGH AT THIS TIME AN ADVISORY MAY
NOT BE NEEDED. RAIN MAY REDUCE VSBYS BELOW 2-3 NM SUNDAY NIGHT
THROUGH MONDAY IN PERIODS OF LIGHT RAIN OR DRIZZLE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/TRA
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1151 PM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 1151 PM CST WED DEC 24 2014
THE RADAR CONTINUES TO SHOW SOME LIGHT RETURNS OVER THE SOUTHERN
COUNTIES...AND THE HRRR IS NOT DOING TOO BAD CAPTURING THIS. ALL
THE SHORT RANGE MODELS HAVE THE WEAK PRECIP IN THE NEXT FEW HOURS
DISSIPATING AND THEN THE NEXT STRONGER SNOW BAND MOVES IN...MAINLY
TO OUR SOUTH. TRIED TO SHOW THAT IN THE GRIDS BY TAPERING POPS
DOWN AND THEN BACK UP. ADJUSTED CLOUDS TO INCLUDE THE CLEARING IN
THE NORTHWEST THAT WILL BE SHORT LIVED.
UPDATE ISSUED AT 949 PM CST WED DEC 24 2014
A FEW RADAR RETURNS HAVE DEVELOPED OVER THE SOUTHWESTERN COUNTIES
OVER THE LAST FEW HOURS. NO REPORTS FROM OBS SITES IN OUR
COUNTIES...BUT WEB CAM AT OAKES SHOWS SOME DECENT LIGHT SNOW
FALLING. INCLUDED SOME MEASURABLE POPS IN THE SOUTHWEST ALONG WITH
SCATTERED FLURRIES IN THE REST OF THE FORECAST AREA THAT HAS
CLOUDS. AMOUNTS WILL BE NO MORE THAN A DUSTING. THE CLEAR SKIES
HAVE PERSISTED IN THE DEVILS LAKE BASIN AND HAVE BEEN SPREADING
EAST...BUT SOME STRATUS HAS ALREADY STARTED TO MOVE DOWN OUT OF
CANADA. ADJUSTED CLOUDS TO ACCOUNT FOR THIS AND HAVE THE DROP IN
TEMPS STEADYING OFF AS THE CLOUDS MOVE IN FROM THE NORTH.
UPDATE ISSUED AT 657 PM CST WED DEC 24 2014
SAT LOOP SHOWS SOME CLEARING IN OUR NORTHWESTERN COUNTIES ALONG
THE SFC TROUGH AXIS...ALTHOUGH WITH MORE STRATUS SEEN UPSTREAM DO
NOT THINK THE CLEARING WILL LAST ALL NIGHT. ADJUSTED SKY GRIDS TO
INCLUDE SOME CLEARING FOR A PERIOD THIS EVENING...AND LOWERED
TEMPS A BIT IN THAT AREA. SOME LIGHT SNOW MOVING ACROSS MAINLY THE
NORTHERN CWA...SO KEPT LOW POPS AND A SCATTERED FLURRY MENTION
FURTHER SOUTH.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM CST WED DEC 24 2014
MAIN 500 MB SHORT WAVE MOVING THROUGH SOUTHERN MANITOBA THIS AFTN
WITH SNOW MOSTLY CONFINED TO WINNIPEG AND POINTS NORTH. RADAR
RETURNS STRONG ENOUGH TO SIGNAL PROBABLY SOME LIGHT SNOW REACHING
THE GROUND IN AREAS SOUTHWARD INTO NE NORTHEAST NORTH DAKOTA TO
DEVILS LAKE. WILL KEEP LOW POPS FOR MEASURABLE IN THE FAR NORTHERN
RRV OVER TO LAKE OF THE WOODS THIS EVENING WITH FLURRIES FURTHER
SOUTH.
OVERNIGHT...SOUTH WINDS AHD OF TROUGH TO LIKELY SATURATE THE LOW
LEVELS FOR SOME PATCHY FREEZING DRIZZLE OR FLURRIES/FOG EAST OF
THE RED RIVER VALLEY SO MENTIONED THAT. BY 09Z TROUGH WILL BE IN
THE RED RIVER VALLEY AND MOVE EAST PAST BEMIDJI 12Z-15Z PERIOD.
KEPT FLURRIES AND SOME FZDZ EAST OF THE VALLEY THRU CHRISTMAS
MORNING UNTIL FRONT CLEARS AREA AND A BIT COLDER AIRMASS ARRIVES.
FARTHER SOUTH...MODELS CONTINUE IDEA OF A NARROW BAND OF
FRONTOGENETIC FORCING MOVING EAST THRU NRN SD INTO CNTRL MN VERY
LATE TONIGHT AND INTO CHRISTMAS DAY AND NIGHT. EXPECT SOME LIGHT
SNOW IN THIS BAND BUT FORCING AND MOISTURE FOR ANY SIGNIFICANT
SNOWFALL IS NOT THERE IN OUR AREA WITH ONLY 1 INCH PSBL IN FAR
SOUTHERN GRANT COUNTY MN WITH LIKELY A DUSTING TO A FEW TENTHS
ALONG THE IMMEDIATE SOUTH DAKOTA BORDER EAST TO FERGUS FALLS AND
WADENA.
COLDER AIR WILL ARRIVE THURSDAY OVERNIGHT AND HOPEFUL FOR SOME
CLEARING INTO THE DVL REGION AS COLDER AND DRIER AIRMASS MOVES IN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 PM CST WED DEC 24 2014
FRIDAY WILL SEE COLDER AIR MOVING SOUTHEAST GRADUALLY AND DRIER
AIRMASS MOVING IN. ANY LIGHT SNOW OR FLURRIES IN SOUTHEAST OF A
BDE-DTL LINE WILL END IN THE MORNING. HIGH PRESSURE WILL MOVE IN
FRIDAY NIGHT WITH LOWS A LOT COLDER THAN WE ARE USED TOO LATELY
WITH LOWS -5F TO 10 ABOVE NORTHWEST TO SOUTHEAST. SATURDAY WILL BE
DRY AND FOR A CHANGE SEASONABLY COLD WITH SOME SUNSHINE.
LONG WAVE UPPER LEVEL RIDGE BUILDS OVER THE NORTHEASTERN PACIFIC ON
DAY 4. DOWNSTREAM LONG WAVE TROUGH TO EXTEND FROM HUDSON BAY TO THE
DESERT SOUTHWEST. LONG WAVE TROUGH EXPANDS FARTHER SOUTH AND EAST
THROUGH DAY 8. WHILE LONG WAVE PATTERN IS RELATIVELY STATIC, THE
UPPER AIR PATTERN IS MODERATELY PROGRESSIVE WITH SHORT WAVES MOVING
THROUGH THE FLOW.
ECMWF AND GFS WERE IN REASONABLE AGREEMENT AT 84 HOURS. HOWEVER THE
ECMWF BECOMES THE FASTER SOLUTION AT THE BEGINNING, THEN THE GFS
BECOMES THE FASTER SOLUTION AFTER TUE. WILL BLEND THE TWO MODELS.
WILL ADD LOW POPS IN THE SOUTHERN ZONES FOR SUN WITH FRONTAL
BOUNDARY MOVING THROUGH.
HIGH TEMPS WERE DECREASED ONE TO FIVE DEGREES ON SUN, DECREASED A
DEGREE OR SO FOR MON AND TUE, AND INCREASED FOUR TO ELEVEN DEGREES
ON WED FROM THIS MORNINGS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1151 PM CST WED DEC 24 2014
KDVL REMAINS VFR WITH THE DRY AIR REDUCING STRATUS...BUT GIVING
THE STRATUS ON SATELLITE ALREADY MOVING DOWN INTO TOWNER COUNTY TO
THE NORTH IT WILL BE VERY SHORT LIVED. JUDGING BY SAT TRENDS THINK
THAT KGFK AND KFAR COULD GO VFR FOR A SHORT PERIOD IN THE NEXT FEW
HOURS BUT THEN GO BACK DOWN TO MVFR AND IFR AS MORE STRATUS MOVES
IN FROM THE NORTH. NOT SO SURE KBJI AND KTVF WILL SEE MUCH
CLEARING...ALTHOUGH KBJI HAS 5000 FT CEILINGS AT THE CURRENT TIME.
THINK THAT TOWARDS MORNING THERE WILL BE MORE IFR CIGS...AND ANY
SNOW WILL STAY SOUTH OF THE TAF SITES. THERE SHOULD BE SOME
IMPROVEMENT TO MVFR TOWARDS AFTERNOON. WINDS WILL SHIFT TO THE
NORTHWEST AT AROUND 8 TO 12 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...RIDDLE
LONG TERM...HOPPES/RIDDLE
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
407 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WAS MOVING EAST TOWARD THE COAST THIS MORNING. HIGH
PRESSURE OVER THE GULF COAST WILL THEN BUILD ACROSS THE EASTERN
UNITED STATES TODAY AND REMAIN OVER THE REGION THROUGH SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...
AT 4AM...COLD FRONT WAS JUST EXITING THE FAR EASTERN COUNTIES OF THE
FORECAST AREA. THE WESTERN EDGE OF THE FRONTAL PRECIPITATION
EXTENDED FROM CHARLOTTESVILLE TO DANVILLE. LATEST HRRR HAS THIS
PRECIPITATION EXITING THE EASTERN COUNTY WARNING AREA AROUND
10Z/5AM. WILL KEEP CHANCE OF SHOWERS IN THE WESTERN UPSLOPE AREAS
THIS MORNING. MOISTURE ABOVE 700 MB MOVES OUT OF THE FORECAST AREA
THIS MORNING ALONG WITH THE COLD FRONT. MODELS ERODE THE LOW LEVEL
MOISTURE THIS EVENING. WILL KEEP SOME CLOUD COVER IN THE NORTHWEST
THROUGH THIS EVENING. LOCATIONS TO THE EAST WILL CLEAR OUT THIS
MORNING.
SURFACE HIGH PRESSURE WAS OVER THE GULF COAST. THE HIGH MOVES ACROSS
THE SOUTHEAST UNITED STATES TODAY AND WILL BE CENTERED OVER THE
FORECAST AREA BY FRIDAY MORNING. SURFACE DEW POINTS DROP INTO THE
20S BY LATE TODAY. WITH THE DRY AIR MASS THAT WILL BE IN
PLACE...DIURNAL VARIATION IN TEMPERATURES WILL BE 20 TO 25 DEGREES.
EXPECT VALLEYS TO DECOUPLE THIS EVENING. WILL KEEP LOW TEMPERATURES
AT OR BELOW GUIDANCE TONIGHT.
MSAS SHOWED BEST PRESSURE RISES OVER THE GREAT LAKES EXTENDING INTO
NORTHERN VIRGINIA. 850 WINDS WILL BE AROUND 50 KNOTS FROM THE WEST
EARLY THIS MORNING...BUT WILL STEADILY DIMINISH TO BELOW 20 KNOTS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EST THURSDAY...
HIGH PRESSURE WILL KEEP THE REGION DRY THROUGH SATURDAY.
TEMPERATURES WILL MODERATE AS THE CENTER OF THE HIGH SHIFTS EAST AND
INCREASING SOUTHWEST WINDS USHER IN A WARM AIR ADVECTION PATTERN
ACROSS THE REGION.
SATURDAY NIGHT THROUGH SUNDAY NIGHT A BAROCLINIC ZONE WILL ESTABLISH
ITSELF FROM NEAR THE MISSISSIPPI DELTA NORTHEAST INTO THE LOWER OHIO
VALLEY. A SERIES OF DISTURBANCES WILL TRACK ALONG THIS
BOUNDARY AND BRING MULTIPLE PERIODS OF RAIN ACROSS THE FORECAST
AREA. CONFIDENCE IS LOW REGARDING TIMING AND TRACK OF EACH OF THESE
SYSTEMS BASED UPON THE GENEROUS SPREAD IN MODEL SOLUTIONS OF THE
FEATURES. HOWEVER...BY THE DAY SUNDAY...IT IS LIKELY THAT RAIN WILL
OCCUR DURING SOME PERIOD OF THE DAY TIME HOURS...AND LIKEWISE DURING
THE SUNDAY NIGHT PERIOD.
TEMPERATURES WILL BE ABOVE NORMAL DURING THIS PERIOD OF THE FORECAST.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
THE LARGE SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A
LITTLE COOLER THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE
TEMPERATURE FORECAST. WHILE I HAVE LOWERING POPS EACH
DAY...LARGELY DUE TO INCREASING UNCERTAINTY...AM KEEPING A LOW CHC
TO SLIGHT CHC IN THROUGH THE PERIOD WITH MORE INDICATION OF SOME
WINTRY PRECIP AS WE GET INTO TUES NIGHT AND WED.
OVERALL...FORECAST REALLY REFLECTS A VERY BROAD BRUSH RATHER THAN
GOING EXACTLY WITH ANY ONE SOLUTION...AND EXPECT THERE WILL BE
QUITE A FEW CHANGES TO THE EARLY WEEK FORECAST AS WE GET INTO THE
WEEKEND. NOT MUCH CHANCE FOR A MAJOR STORM DURING THIS
PERIOD...AND AFTER SUNDAY ITS POSSIBLE THAT DRY BUT COOL HIGH
PRESSURE MANAGES TO DOMINATE...BUT BEST GUESS FOR NOW IS SOMETHING
IN BETWEEN. AS ALWAYS...STAY TUNED!
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
FLYING CONDITIONS WILL GRADUALLY IMPROVE OVERNIGHT AS A COLD
FRONT SWEEPS ACROSS FROM THE WEST AND REMOVES THE LINGERING LOW
CLOUDS...FOG AND DRIZZLE THAT HAVE PERSISTED WITHIN A STRONG WEDGE
FOR THE LAST COUPLE OF DAYS. HOWEVER EASTERN SITES SUCH AS
KLYH/KDAN MAY STILL BE SLOW TO IMPROVE TO MVFR UNTIL EARLY
THURSDAY WHEN BETTER MIXING BEHIND THE FRONT DEVELOPS. THUS WILL
BE HOLDING ONTO LINGERING IFR THERE INTO THE OVERNIGHT WITH A SLOW
RISE IN BOTH CIGS AND VSBYS BY DAWN. ELSW STILL LOOKING AT MVFR
CIGS FOR THE MOST PART WITH IFR FAR WEST GIVEN UPSLOPE FLOW INTO
KBLF OVERNIGHT. A FEW SHOWERS STILL POSSIBLE OVER THE AREA DURING
THE NEXT FEW HOURS BEFORE MORE UPSLOPE NATURE RAIN/SNOW SHOWERS
GET GOING TOWARD SUNRISE.
WEST WINDS WILL REMAIN STRONG AT TIMES OVER THE WEST OVERNIGHT
WITH GUSTS TO 30-40 MPH POSSIBLE WITH LIGHTER SPEEDS WITHIN THE
LINGERING WEDGE AT KLYH/KDAN.
THURSDAY...MVFR CEILINGS AND UPSLOPE RAIN/SNOW SHOWERS SHOULD
PERSIST IN THE MOUNTAINS...MAINLY KBLF/KLWB INTO EARLY AFTERNOON
WITH VFR CONDITIONS RETURNING IN THE PIEDMONT. IN BETWEEN...SOME
LINGERING MVFR STRATO-CU POSSIBLE AROUND KBCB/KROA THURSDAY
MORNING BEFORE THINGS MIX OUT UNDER GUSTY WESTERLY WINDS BY
MIDDAY. WINDS AGAIN MAY GUST TO 25-30 KTS THURSDAY MORNING BEFORE
QUICKLY DIMINISHING DURING THURSDAY AFTERNOON AS HIGH PRESSURE
BUILDS IN.
EXTENDED DISCUSSION...
THURSDAY NIGHT AND FRIDAY HIGH PRESSURE SHOULD BUILD OVER THE
SOUTHEAST...WHICH WILL PROVIDE VFR WEATHER WITH LIGHTER WINDS.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. GIVEN
THE SLOWER TRENDS...APPEARS WEATHER MAY STAY VFR FOR SATURDAY WITH
SUB-VFR CONDITIONS RETURNING WITH CLOUDS/PRECIP ON SUNDAY FOR NOW.
BOUNDARY MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT
WEEK WITH POSSIBLE RETURN TO VFR MONDAY AFTERNOON AT THIS POINT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...SK
AVIATION...JH/RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1134 PM EST WED DEC 24 2014
.SYNOPSIS...
A COLD FRONT WILL SWING EAST ACROSS THE REGION OVERNIGHT BRINGING
GUSTY WEST WINDS AND DRIER AIR BY CHRISTMAS MORNING. HIGH
PRESSURE WILL THEN BUILD OVER THE EASTERN UNITED STATES THURSDAY INTO
THE WEEKEND WITH GENERALLY FAIR WEATHER EXPECTED INTO SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
SHOWERS FOR LATE IN THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 925 PM EST WEDNESDAY...
COLD FRONT NOW PUSHING ACROSS THE FAR WESTERN COUNTIES SHOULD
REACH THE BLUE RIDGE BY MIDNIGHT AND OUT EAST DURING THE EARLY
MORNING HOURS. MOST SHOWERS HAVE ALL BUT DISSIPATED ALONG THE
BOUNDARY UPON ENCOUNTERING THE LINGERING WEDGE BUT STILL APPEARS A
FEW LIGHTER BANDS OF SHOWERS POSSIBLE OVER THE WEST DURING THE
NEXT COUPLE OF HOURS. HOWEVER NOT ENOUGH TO KEEP ANY THUNDER GOING
NW WITH A GRADUAL REDUCTION IN POPS WEST UNTIL SEEING THE BRIEF
UPSLOPE KICK IN LATER ON. OTHER CONCERN IS OUT EAST WHERE THE
FRONT WILL LIKELY SLOW UNDER THE SW FLOW ALOFT ALLOWING PERHAPS
ANOTHER SPEED MAX TO ZIP UP FROM THE SOUTH INTO THE EARLY MORNING
HOURS. LATEST HRRR CONTINUES TO SUGGEST A FEW ADDED HOURS OF RAIN
ESPCLY PIEDMONT AND SUPPORTED BY THE 00Z NAM SO ADDED IN MORE
CHANCE POPS EAST OVERNIGHT ESPCLY GIVEN FILLING BACK IN OF PRECIP
ON REGIONAL RADARS TO THE SOUTH ATTM. OTRW SEEING A TEMP DROP OF
ALMOST 10 DEGREES IN AN HOUR DURING THE FROPA WITH GUSTS TO 30-35
KTS BUT STILL BELOW ADVISORY GIVEN LEVELING OFF OF SPEEDS ONCE THE
BOUNDARY CROSSES. EXPECT FOG TO FINALLY FADE ENOUGH AFTER MIDNIGHT
TO DROP MENTION FOR THE MOST PART OVERNIGHT AS WELL. BUMPED UP LOW
TEMPS IN THE EAST WHERE ONCE THE WEDGE BREAKS EXPECT A BRIEF TEMP
SURGE FOR A COUPLE HOURS BEFORE GRADUAL COOLING REDEVELOPS BEHIND
THE FRONT. HOWEVER GIVEN MIXING EXPECT LOWS TO BE A FEW DEGREES
WARMER THAN EARLIER THOUGHT.
PREVIOUS UPDATE AS OF 520 PM EST WEDNESDAY...
SENT AN UPDATE TO BOOST DENSE FOG COVERAGE ALONG/EAST OF THE BLUE
RIDGE THIS EVENING BEFORE THE COLD FRONT FINALLY ARRIVES AND HELPS
MIX THINGS OUT BEFORE MIDNIGHT. ALSO ISSUED A SPS FOR THE
FOOTHILLS AND PIEDMONT GIVEN THE QUICK DROPOFF IN VISIBILITIES
OVER THE PAST HOUR. MAY NEED A BRIEF ADVISORY IF CONDITIONS WORSEN
BUT HOLDING OFF FOR NOW GIVEN THE GRADUAL APPROACH OF THE FRONT
FROM THE WEST. ALSO TWEAKED POPS DOWN AND ADDED MORE DRIZZLE BLUE
RIDGE EAST WHILE DELAYING CONVECTION OVER THE WEST. MOST LATEST
SHORT TERM SOLUTIONS QUICKLY WEAKEN THIS SHALLOW CONVECTION UPON
CROSSING THE WESTERN SLOPES IN THE NEXT COUPLE OF HOURS BUT
SOMETHING TO WATCH. TEMPS REMAIN STUCK IN THE 40S ACROSS THE
CENTRAL AND EAST SO ADJUSTED DOWN FOR STEADY READINGS THERE THIS
EVENING BEFORE SEEING A QUICK JUMP WHEN THE FRONT ARRIVES AFTER
00Z.
PREVIOUS DISCUSSION AS OF 340 PM EST WEDNESDAY...
AT 3 PM...THE WEDGE OF COOL SHALLOW AIR REMAINED ALONG AND EAST
OF THE BLUE RIDGE. THIS MORNING...A SHORT WAVE PASSED OVER THIS
WEDGE AND BROUGHT A FAIR AMOUNT OF RAIN (0.50 TO 1.50 INCHES) TO
THE REGION. THIS WAVE HAS PASSED WITH ONLY LIGHT RAIN/DRIZZLE LEFT
IN ITS WAKE. GRAY CLOUDY CONDITIONS WILL PERSIST INTO THIS EVENING
WHILE A LULL IN THE RAIN WILL LAST FOR A FEW HOURS BEFORE A COLD
FRONT AND ASSOCIATED SHOWERS ENTER THE WEST LATE THIS
AFTERNOON...EXITING THE PIEDMONT LATE THIS EVENING. THE WEDGE HAS
LEFT MOST OF THE AREA IN A STABLE ENVIRONMENT BUT CAN NOT RULE OUT
A RUMBLE OF THUNDER FROM ELEVATED CONVECTION AS THE COLD FRONT
PASSES THIS EVENING.
SHOWERS WITH THE FRONT MAY HAVE SOME GUSTY WINDS WITH THEM...BUT
IT WILL BE THE SHARP PRESSURE RISES BEHIND THE FRONT THAT WILL
BRING A FEW HOURS OF BREEZY AND GUSTY CONDITIONS TO THE REGION.
THE STRONGER LONGER LASTING BREEZY AND GUSTY WINDS WILL OCCUR
EARLY CHRISTMAS MORNING WITH A TIGHT PRESSURE GRADIENT...MODEST
COLD AIR ADVECTION AND A 50 KT LOW LEVEL JET. HIGH PRESSURE BUILDS
IN QUICKLY THURSDAY AFTERNOON TO SHUT DOWN THE WINDS.
AS THE WEDGE ERODES...TEMPERATURES ARE WARMING INTO THE MID TO
UPPER 50S. AREA ALONG AND EAST OF THE BLUE RIDGE...PARTICULARLY IN
THE FOOTHILLS AND PIEDMONT COUNTIES...MAY NOT SEE HIGH
TEMPERATURES TODAY UNTIL THIS EVENING (5P-7P). ONCE THE FRONT
MOVES EAST...TEMPERATURES WILL SLOWLY DROP INTO THE 30S AND 40S.
AS THE UPPER LEVEL TROUGH PASSES OVERHEAD FRIDAY MORNING...A FEW
SHOWERS ARE POSSIBLE. TEMPERATURES AND BOUNDARY LAYER ARE TO WARM
FOR SNOW EXCEPT FOR HIGHER ELEVATIONS AND WESTERN SLOPES. AFTER A
BREEZY COOL MORNING...AFTERNOON HIGHS WILL WARM INTO THE 40S WEST
TO 50S EAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 250 PM EST WEDNESDAY...
TRANQUIL AND MILD CONDITIONS ARE IN STORE FOR THE INITIAL POST-
CHRISTMAS PERIOD OVER THE CENTRAL/SOUTHERN APPALACHIAN REGION. A
SURFACE AND UPPER RIDGE OF HIGH PRESSURE CENTERED OVER THE
SOUTHEASTERN U.S. WILL DOMINATE THE PATTERN IN OUR REGION FOR
SEVERAL DAYS AS UPPER TROUGHING AND STORMINESS IS CONFINED TO THE
WESTERN CONUS. VERY MILD TEMPS ON FRIDAY WITH WIDESPREAD 50S
LIKELY FOR HIGHS UNDER A PLEASANT LATE DECEMBER SUN. WINTER
WEATHER LOVERS PREPARE TO BE LESS THAN PLEASED.
THE HIGH WILL SHIFT OFF THE EAST COAST BY LATE SATURDAY AS HEIGHT
FALLS AND A COLD FRONT OVER THE MID-MISSISSIPPI VALLEY SLOWLY PUSH
EAST. SKIES WILL BE CLEAR FRIDAY NIGHT AND MOST OF SATURDAY WITH
TEMPERATURES AGAIN RUNNING 10-15F ABOVE LATE DECEMBER
NORMALS...LOWS IN LOW TO MID-30S AND HIGHS LOW 50S TO NEAR 60.
HIGH CLOUDS WILL INCREASE LATE SATURDAY AHEAD OF THE FRONT WITH
ANOTHER MILD NIGHT IN STORE AS TEMPS LIKELY TO REMAIN ABOVE
FREEZING IN NEARLY ALL AREAS. POPS SLOWLY INCREASE AS WELL TO CHC
BY EARLY SUNDAY IN THE FAR WEST WITH RAIN AS THE P-TYPE IN ALL BUT
VERY COLDEST LOCATIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
SUNDAY INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
A LITTLE MORE CONFIDENCE AT THE BEGINNING OF THIS PERIOD...SO
HAVE SOME LIKELY AND HIGH CHC POPS IN FOR SUNDAY...BUT ALL
RAIN...AND MOST LIKELY LIGHT. AS WE GET INTO THE WEEK...THE LARGE
SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A LITTLE COOLER
THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE TEMPERATURE
FORECAST. WHILE I HAVE LOWERING POPS EACH DAY...LARGELY DUE TO
INCREASING UNCERTAINTY...AM KEEPING A LOW CHC TO SLIGHT CHC IN
THROUGH THE PERIOD WITH MORE INDICATION OF SOME WINTRY PRECIP AS
WE GET INTO TUES NIGHT AND WED. OVERALL...FORECAST REALLY REFLECTS
A VERY BROAD BRUSH RATHER THAN GOING EXACTLY WITH ANY ONE
SOLUTION...AND EXPECT THERE WILL BE QUITE A FEW CHANGES TO THE
EARLY WEEK FORECAST AS WE GET INTO THE WEEKEND. NOT MUCH CHANCE
FOR A MAJOR STORM DURING THIS PERIOD...AND AFTER SUNDAY ITS
POSSIBLE THAT DRY BUT COOL HIGH PRESSURE MANAGES TO DOMINATE...BUT
BEST GUESS FOR NOW IS SOMETHING IN BETWEEN. AS ALWAYS...STAY
TUNED!
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
FLYING CONDITIONS WILL GRADUALLY IMPROVE OVERNIGHT AS A COLD
FRONT SWEEPS ACROSS FROM THE WEST AND REMOVES THE LINGERING LOW
CLOUDS...FOG AND DRIZZLE THAT HAVE PERSISTED WITHIN A STRONG WEDGE
FOR THE LAST COUPLE OF DAYS. HOWEVER EASTERN SITES SUCH AS
KLYH/KDAN MAY STILL BE SLOW TO IMPROVE TO MVFR UNTIL EARLY
THURSDAY WHEN BETTER MIXING BEHIND THE FRONT DEVELOPS. THUS WILL
BE HOLDING ONTO LINGERING IFR THERE INTO THE OVERNIGHT WITH A SLOW
RISE IN BOTH CIGS AND VSBYS BY DAWN. ELSW STILL LOOKING AT MVFR
CIGS FOR THE MOST PART WITH IFR FAR WEST GIVEN UPSLOPE FLOW INTO
KBLF OVERNIGHT. A FEW SHOWERS STILL POSSIBLE OVER THE AREA DURING
THE NEXT FEW HOURS BEFORE MORE UPSLOPE NATURE RAIN/SNOW SHOWERS
GET GOING TOWARD SUNRISE.
WEST WINDS WILL REMAIN STRONG AT TIMES OVER THE WEST OVERNIGHT
WITH GUSTS TO 30-40 MPH POSSIBLE WITH LIGHTER SPEEDS WITHIN THE
LINGERING WEDGE AT KLYH/KDAN.
THURSDAY...MVFR CEILINGS AND UPSLOPE RAIN/SNOW SHOWERS SHOULD
PERSIST IN THE MOUNTAINS...MAINLY KBLF/KLWB INTO EARLY AFTERNOON
WITH VFR CONDITIONS RETURNING IN THE PIEDMONT. IN BETWEEN...SOME
LINGERING MVFR STRATO-CU POSSIBLE AROUND KBCB/KROA THURSDAY
MORNING BEFORE THINGS MIX OUT UNDER GUSTY WESTERLY WINDS BY
MIDDAY. WINDS AGAIN MAY GUST TO 25-30 KTS THURSDAY MORNING BEFORE
QUICKLY DIMINISHING DURING THURSDAY AFTERNOON AS HIGH PRESSURE
BUILDS IN.
EXTENDED DISCUSSION...
THURSDAY NIGHT AND FRIDAY HIGH PRESSURE SHOULD BUILD OVER THE
SOUTHEAST...WHICH WILL PROVIDE VFR WEATHER WITH LIGHTER WINDS.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. GIVEN
THE SLOWER TRENDS...APPEARS WEATHER MAY STAY VFR FOR SATURDAY WITH
SUB-VFR CONDITIONS RETURNING WITH CLOUDS/PRECIP ON SUNDAY FOR NOW.
BOUNDARY MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT
WEEK WITH POSSIBLE RETURN TO VFR MONDAY AFTERNOON AT THIS POINT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/RCS
NEAR TERM...JH/RCS
SHORT TERM...PC
LONG TERM...SK
AVIATION...JH/RCS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
350 AM MST THU DEC 25 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 346 AM MST THU DEC 25 2014
AN UPPER LEVEL LOW WILL CLOSE OFF OVER UTAH TODAY AND THEN MOVE INTO
THE FOUR CORNERS AREA BY LATE TONIGHT. AT THE SFC LOW PRES WILL
INTENSIFY JUST SOUTH OF DENVER THRU THE AFTN AND THEN MOVE SE INTO
SERN CO BY EARLY THIS EVENING. MEANWHILE A SURGE OF COOLER AIR WILL
GRADUALLY MOVE INTO NERN CO THRU THE DAY WITH INCREASING UPSLOPE
FLOW NORTH OF THE BNDRY LATER THIS AFTN INTO THE EVENING HOURS.
MEANWHILE WILL SEE SOME MID LVL ASCENT ACROSS THE AREA LATER THIS
AFTN INTO TONIGHT WITH DIFFLUENT FLOW ALOFT. SNOW WILL INCREASE IN
THE MTNS THIS AFTN AND AT LOWER ELEVATIONS NR THE WY BORDER BY 21Z
WITH ADDITIONAL DEVELOPMENT SPREADING SOUTH ACROSS THE NRN FOOTHILLS
AND IN AREAS FROM FORT COLLINS TOWARDS BOULDER. AM SOMEWHAT
CONCERNED WITH INCREASING ENE FLOW AND POTENTIAL FOR HEAVIER
SNOWFALL IN ZNS 38 AND 39 FOR THIS EVENING ALONG AND WEST OF I-25.
LATEST RAP IS SHOWING INCREASING POTENTIAL FOR 6 TO 8 INCHES OVER A
3 TO 4 HOUR PERIOD FROM 23Z TO 03Z. THUS WILL UPGRADE ADVISORY TO A
WARNING FOR THESE AREAS. FURTHER SOUTH OVER DENVER HEAVIER SNOW MAY
ALSO DEVELOP OVER THE WRN SUBURBS AT SOME POINT WITH SOME POTENTIAL
FOR WARNING CRITERIA LATER THIS EVENING HOWEVER OVERALL CONFIDENCE
IS NOT AS HIGH SO WILL KEEP CURRENT ADVISORY IN PLACE.
OVER THE PLAINS WILL SEE SNOW GRADUALLY DEVELOP THIS EVENING WITH
ADVISORY AMOUNTS POSSIBLE IN SOME AREAS. WINDS WILL NOT BE REAL
STRONG HOWEVER WILL PROBABLY SEE SOME REDUCED VISBILITIES AT TIMES.
IN THE MTNS AND FOOTHILLS WILL KEEP PREVIOUS HIGHLIGHTS INTACT
ALTHOUGH SRN FOOTHILLS AND PALMER DIVIDE MAY NOT SEE HEAVIER
SNOWFALL UNTIL AFTER 03Z.
FOR LATER TONIGHT AROUND MIDNIGHT SNOW INTENSITIES MAY BEGIN TO
DECREASE HOWEVER WILL LIKELY SEE AREAS OF STEADIER LIGHT SNOW
THROUGH SUNRISE IN MOST AREAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MST THU DEC 25 2014
ON FRIDAY...THE UPPER TROUGH WILL BE IN THE VICINITY OF THE FOUR
CORNERS AT 12Z...IT WILL GRADUALLY OPEN UP AND SHIFT EASTWARD
THROUGH THE DAY. THE TROUGH AXIS ITSELF IN PROGGED TO SHIFT TO THE
EAST OF COLORADO BY FRIDAY EVENING. WEAK QG ASCENT WILL BE PRESENT
FRIDAY MORNING...THEN DECREASE THROUGH THE REST OF THE DAY.
ADDITIONAL ACCUMULATIONS ON FRIDAY WILL BE LIGHT...MAYBE ANOTHER 1
TO 4 INCHES IN THE HIGH COUNTRY...AND ANOTHER 1 TO 2 INCHES OVER
THE NORTHEAST PLAINS. A DRIER NORTHWEST TO WESTERLY FLOW ALOFT
WILL DEVELOP LATE FRIDAY NIGHT INTO SATURDAY. LINGERING MOISTURE
AROUND FRIDAY NIGHT SO WL KEEP CHC POPS IN THE MOUNTAINS. MAIN
ADJUSTMENT TO THE GRIDS ON FRIDAY AND FRIDAY NIGHT WAS TO SLOW THE
TIMING A BIT. SATURDAY AND SATURDAY NIGHT...A SHORT WAVE RIDGE
WILL BE OVER THE REGION WITH THE FLOW ALOFT INCREASING AHEAD OF
THE NEXT SYSTEM IN THE PACIFIC NORTHWEST. MOISTURE WILL INCREASE
OVER THE MOUNTAINS BY SUNDAY AFTERNOON WITH INCREASING MID AND
UPPER LEVEL QG ASCENT DEVELOPING AS THE TROUGH MOVES INTO SRN
ID/SWRN WY. THE MDLS KEEP THE TROF AXIS TO THE NORTH AND WEST OF
COLORADO SUNDAY NIGHT WITH A 100 KT WEST TO EAST UPPER JET
TRANSLATING SOUTHWARD ACROSS THE STATE. COULD SEE SOME ENHANCED
CSI BANDS DEVELOP AS WE SLIP TO THE NORTHERN SIDE OF THE JET MAX.
WL GO WITH LIKELY POPS IN THE MOUNTAINS...AND AGAIN SOME
HIGHLIGHTS MAY NEED TO BE POSTED AT SOME POINT. AN ARCTIC COLD
FRONT WILL MOVE INTO THE FRONT RANGE SUNDAY NIGHT INTO MONDAY
MORNING. TEMPERATURES ON MONDAY WL ONLY REACH THE UPPER TEENS. WL
GO WITH CHC POPS AS WELL. ALTHOUGH TIMING WL AGAIN BE AN
ISSUE...WL GO WITH THE TREND OF DRIER BUT CONTINUED COLD FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 346 AM MST THU DEC 25 2014
AT THIS TIME IT APPEARS BEST CHC OF SNOW AT DIA WILL HOLD OFF UNTIL
AFTER 5 PM WITH AN INCREASE IN COVERAGE AND INTENSITY THRU THE EARLY
EVENING HOURS. SNOW INTENSITY WILL DECREASE BY MIDNIGHT HOWEVER
WILL CONTINUE TO SEE LIGHT SNOW THRU SUNRISE. RIGHT NOW WILL GO
WITH ACCUMULATIONS IN THE 3 TO 5 INCH RANGE FOR DIA FM 5 PM THRU 5
AM.
AS FOR WINDS OVERALL CONFIDENCE NOT THAT HIGH FOR LATER THIS MORNING
THRU THE AFTN. LATEST HRRR AND RAP HAVE BEEN SHOWN A SFC LOW
DEVELOPING JUST TO THE SOUTH OF THE AIRPORT BY MID TO LATE MORNING
WHICH SHIFTS SLOWLY SOUTH THRU THE AFTN. AS A RESULT SSW WINDS THIS
MORNING MAY BECOME MORE ELY BY 18Z AND STAY THAT WAY THRU LATE AFTN.
AFTER 00Z WINDS MAY WILL BECOME MORE NELY AND THEN MORE NLY AROUND
MIDNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ035-036-039.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ031-033-034.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 8 AM MST FRIDAY
FOR COZ038.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM MST
FRIDAY FOR COZ042-043.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ040-045-046.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ041.
&&
$$
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
706 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 704 AM CST THU DEC 25 2014
LITTLE CHANGE WAS MADE TO THE FORECAST AT THIS POINT. SOME
ADJUSTMENT TO CLOUD COVER DUE TO STRATUS TAILING BACK ACROSS THE
NORTHEAST.
&&
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/12Z
ISSUED AT 554 AM CST THU DEC 25 2014
STRATUS CURRENTLY FROM JUST EAST OF KMCW TO JUST WEST OF KCID AND
WILL CONTINUE TO PUSH EAST TODAY. MID LEVEL CLOUD COVER WILL
INCREASE IN WARM ADVECTION TODAY PRODUCING VFR CIGS. SOUTHERLY
WINDS WILL INCREASE TODAY IN STRENGTHENING WARM ADVECTION AHEAD OF
THE NEXT SYSTEM WHICH WILL MOVE INTO TAF LOCATIONS BY LATE IN THE
PERIOD. CIGS WILL ONCE AGAIN GO BACK TO IFR WITH A WIND SHIFT TO
THE NORTH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...FAB
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
554 AM CST THU DEC 25 2014
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/12Z
ISSUED AT 554 AM CST THU DEC 25 2014
STRATUS CURRENTLY FROM JUST EAST OF KMCW TO JUST WEST OF KCID AND
WILL CONTINUE TO PUSH EAST TODAY. MID LEVEL CLOUD COVER WILL
INCREASE IN WARM ADVECTION TODAY PRODUCING VFR CIGS. SOUTHERLY
WINDS WILL INCREASE TODAY IN STRENGTHENING WARM ADVECTION AHEAD OF
THE NEXT SYSTEM WHICH WILL MOVE INTO TAF LOCATIONS BY LATE IN THE
PERIOD. CIGS WILL ONCE AGAIN GO BACK TO IFR WITH A WIND SHIFT TO
THE NORTH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS JACKSON KY
938 AM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 938 AM EST THU DEC 25 2014
UPDATED GRIDS FOR LATEST HOURLY OBS AND TRENDS. THIS RESULTED IN VERY
MINOR CHANGES TO THE FORECAST. OVERALL FORECAST IS IN EXCELLENT SHAPE
THIS CHRISTMAS MORNING. STILL PICKING UP ON SOME PATCHY DRIZZLE IN
THE OBS AND ON RADAR. CLOUD TOP TEMPS SUGGEST THERE IS SOME FLURRY
ACTIVITY OUT THERE AS WELL...MAINLY IN THE HIGHER ELEVATIONS. NO
UPDATE TO THE ZONES PLANNED AT THIS TIME.
UPDATE ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 735 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH DEPARTS THE REGION AND LOW LEVEL MOISTURE
REMAINS...DRIZZLE WILL BE POSSIBLE EARLY AT THE TAF SITES WITH LITTLE
OR NO REDUCTION IN VIS. MVFR CIGS ARE EXPECTED...HOWEVER...IN MOST
AREAS FOR THE FIRST 6 HOURS OF THE PERIOD. AS RIDGING BUILDS INTO
THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO EAST AND THEN REMAIN
THERE THROUGH THE END OF THE PERIOD. WINDS WILL REMAIN SOUTHWEST TO
WEST SOUTHWEST AND GENERALLY LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
755 AM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 735 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH DEPARTS THE REGION AND LOW LEVEL MOISTURE
REMAINS...DRIZZLE WILL BE POSSIBLE EARLY AT THE TAF SITES WITH LITTLE
OR NO REDUCTION IN VIS. MVFR CIGS ARE EXPECTED...HOWEVER...IN MOST
AREAS FOR THE FIRST 6 HOURS OF THE PERIOD. AS RIDGING BUILDS INTO
THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO EAST AND THEN REMAIN
THERE THROUGH THE END OF THE PERIOD. WINDS WILL REMAIN SOUTHWEST TO
WEST SOUTHWEST AND GENERALLY LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS BILLINGS MT
336 AM MST THU DEC 25 2014
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL IMPACT KBIL KSHR AND KLVM THIS MORNING BUT SNOW HAS
LARGELY ENDED FOR KMLS. AREAS OF SNOW S AND W OF AND INCLUDING
KBIL WILL CAUSE WIDESPREAD IFR AND AREAS OF LIFR CONDITIONS UNTIL
17Z. CONDITIONS WILL IMPROVE DURING THE AFTERNOON. NORTH AND EAST
OF KBIL EXPECT AREAS OF MVFR CONDITIONS MOSTLY DUE TO CEILINGS.
BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
+/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
+/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
+/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
4/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
+/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
3/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 30-34>37-39>41-57-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
526 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 526 AM CST THU DEC 25 2014
IFR IN SNOW AND LOW CEILINGS WILL SPREAD SOUTH AND WEST TO NEAR
KVTN-KOGA TODAY. THE SAME FLIGHT RESTRICTIONS WILL CREEP SOUTH TO
NEAR KIML-KLBF-KONL BY 12Z FRIDAY MORNING. OTHERWISE VFR WILL
BECOME MVFR WITH THE PASSAGE OF A COLD FRONT TODAY AND TONIGHT.
THE FRONT IS CURRENTLY MOVING THRU SRN SD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON CST /11 AM MST/ TODAY TO NOON
CST /11 AM MST/ FRIDAY FOR NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
954 AM EST THU DEC 25 2014
.SYNOPSIS...
LOW PRESSURE WILL BE PULLING NORTHEAST FROM ONTARIO INTO QUEBEC
TODAY. MEANWHILE HIGH PRESSURE WILL BUILD ACROSS THE OHIO AND
TENNESSEE VALLEYS. THIS WILL SHIFT EAST EARLY SATURDAY AND ALLOW A
COLD FRONT TO CROSS NORTHERN OHIO/PA SATURDAY EVENING. HIGH
PRESSURE RETURNS IN ITS WAKE FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW RAIN SHOWERS/DRIZZLE LOCATED ACROSS THE REGION...MAINLY FROM
THE CENTRAL HIGHLANDS EASTWARD INTO NW PA. CANT COMPLETELY RULE
OUT A FEW SNOW FLAKES BUT IT WONT BE MUCH. OTHERWISE IT LOOKS LIKE
WE MAY ATTEMPT TO SEE A FEW BREAKS OF CLOUDS FOR THE AFTERNOON.
PREVIOUS DISCUSSION...
REALLY NOT A LOT OF COLD AIR BEHIND YESTERDAYS COLD FRONT AND THE
MAJORITY OF THE PRECIP ON THE BACKSIDE PULLED UP THROUGH MI AND
INTO CANADA. THEREFORE NO WHITE CHRISTMAS. STILL A FEW RAIN
SHOWERS OUT THERE EARLY THIS MORNING WITH THE UPPER TROUGH. MAY
SEE SOME WET SNOWFLAKES MIX IN AND ALSO MAY JUST SEE SOME PLAIN
DRIZZLE. TEMPERATURES WILL REMAIN ABOVE FREEZING. THE
PRECIPITATION CHANCES REALLY CONFINED TO THIS MORNING AS WE
QUICKLY TRANSITION TO RIDGING AND WARM ADVECTION. HIGHS FOR TODAY
WILL BE PRETTY MUCH WHERE THEY ARE AT RIGHT NOW...UPPER 30S WITH A
FEW IN THE LOWER 40S. MOSTLY CLOUDY...BUT WILL BE OPTIMISTIC FOR
SOME BREAKS ACROSS SOUTHWEST COUNTIES BEFORE SUNSET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
DRY CONDITIONS FOR TONIGHT THROUGH FRIDAY WITH HIGH PRESSURE
BUILDING ACROSS THE OHIO VALLEY. STILL RELATIVELY MILD WITH NO
SOURCE OF COLD AIR WITH THE WEST-SOUTHWEST FLOW. A SHORTWAVE EMERGES
FROM THE ROCKIES LONGWAVE TROUGH FRIDAY NIGHT TOWARD THE GREAT
LAKES REGION. SURFACE LOW PRESSURE WILL TRACK ACROSS THE LAKES
INTO CANADA AND TAKE A COLD FRONT ACROSS OH/PA SATURDAY NIGHT. AS
IT DOES SO...THE FRONT WILL SLOW AND WEAKEN WHILE THE RIDGE ACROSS
THE SOUTHEAST STATES HOLDS AND ONLY FLATTENS WITH TIME. IT WILL
TAKE SOME TIME ON SATURDAY TO BE ABLE TO GET PRECIP INTO NW OHIO.
WILL FOCUS THE MAJORITY OF THE PRECIP CHANCES ON SATURDAY NIGHT.
TEMPERATURES WILL STILL BE MILD SO EXPECTING THE MAJORITY OF THE
PRECIP TO FALL AS RAIN WITH SOME SNOW CHANCES WITH THE ADVANCING
COLD AIR TOWARD SUNDAY MORNING. TEMPERATURES CLOSER TO NORMAL FOR
SUNDAY. WILL LINGER SNOW SHOWER CHANCES INTO SUNDAY BUT HIGH
BUILDING IN MAY END THAT ALL TOGETHER. WILL KEEP CLOUDS AROUND
SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES FOR THE PERIOD WITH A
RIDGE BUILDING IN FROM THE NORTH. THE MODELS DISAGREE ON THE
MOISTURE. THE GFS IS VERY DRY FOR THE PERIOD WHILE THE ECMWF HAS
MUCH MORE MOISTURE FOR MONDAY THROUGH TUESDAY MORNING. BECAUSE OF
THAT KEPT CHANCE POPS FOR SNOW SHOWERS OVER NE OH AND NW PA AS THE
LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 16C. AS THE
RIDGE BUILDS IN LATER TUESDAY INTO WEDNESDAY THE FLOW BECOMES
SOUTHWEST SO WENT DRY ACROSS THE ENTIRE FORECAST AREA. WENT A LITTLE
COLDER THAN GUIDANCE MAINLY FOR THE HIGHS BASED ON THE FORECASTED
850 MB TEMPERATURES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A RIDGE WILL BE BUILDING INTO THE AREA TODAY. SOME WIDELY
SCATTERED RAIN AND SNOW SHOWERS WILL OCCUR THIS MORNING. OTHERWISE
MVFR CEILINGS WILL SLOWLY RISE. SOME QUESTION ON THE CLEARING FOR
TONIGHT. IT MAKES SENSE WITH THE RIDGE MOVING EAST OF THE AREA.
THE HRRR MODEL KEEPS THE LOW CLOUDS. DELAYED THE CLEARING OF THE
LOW CLOUDS A FEW HOURS...HOWEVER...SOME CIRRUS WILL BE ALOFT.
.OUTLOOK...NON-VFR LATE SATURDAY THROUGH SUNDAY NIGHT AND THEN
MAINLY OVER NE OH AND NW PA MONDAY THROUGH TUESDAY.
&&
.MARINE...
GALE WARNINGS HAVE BEEN DISCONTINUED. WINDS HAVE DIMINISHED BELOW
GALE FORCE ACROSS MUCH OF THE LAKE SO WILL GO AHEAD AND DROP THE
WARNING. WATER LEVELS ON THE WEST END HAVE RISEN ABOVE THE
CRITICAL MARK SO WILL GO AHEAD AND DROP THE LOW WATER ADVISORY.
SINCE WAVES WILL REMAIN WELL ABOVE 4 FEET WILL HOIST AND EXTEND
SMALL CRAFT ADVISORY THROUGH TOMORROW AFTERNOON.
PREVIOUS DISCUSSION...
GALE FORCE WINDS WILL DIMINISH SOMEWHAT QUICKLY FROM THE WEST
TODAY AS WARM ADVECTION WILL BE STARTING AROUND DAYBREAK. WILL
DOWNGRADE THE GALE ON THE WEST END OF THE LAKE TO A SMALL CRAFT
ADVISORY FOR 20 TO 25 KNOT WINDS THROUGH MID AFTERNOON. ON THE
EAST END CONTINUING THE GALE THROUGH 21Z/4PM TODAY AND THEN A
SMALL CRAFT ADVISORY WILL BE NEEDED AFTER THAT. THE FLOW ON THE
LAKE WILL BECOME SOUTHWEST TODAY AS A RIDGE BUILDS INTO THE OHIO
VALLEY. ON FRIDAY SOME QUESTION HOW STRONG THE SOUTHWEST WINDS
WILL BE AND WHETHER A SMALL CRAFT ADVISORY WILL BE
NEEDED...ESPECIALLY ON THE EAST END.
THE WATER LEVEL HAS DROPPED BELOW THE CRITICAL MARK. SOME QUESTION
HOW LOW WILL IT GET WITH THE WINDS NOT THAT STRONG ON THE WEST END.
WILL NOT LET IT DROP BELOW 2 FEET BELOW THE CRITICAL MARK AND
THEN IT SHOULD SLOSH BACK ABOVE THE CRITICAL MARK BY NOON.
A FRONT WILL MOVE ACROSS THE LAKE LATE SATURDAY PROMPTING YET
ANOTHER THREAT FOR A SMALL CRAFT ADVISORY ON THE EAST END. BY SUNDAY
MORNING A RIDGE WILL BE OVER THE LAKE AND THE WINDS WILL DECREASE.
THE RIDGE WILL BE IN CONTROL OF THE WEATHER THROUGH TUESDAY...THUS
NOT EXPECTING THE NEED FOR A SMALL CRAFT ADVISORY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA/LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
702 AM EST THU DEC 25 2014
.SYNOPSIS...
LOW PRESSURE WILL BE PULLING NORTHEAST FROM ONTARIO INTO QUEBEC
TODAY. MEANWHILE HIGH PRESSURE WILL BUILD ACROSS THE OHIO AND
TENNESSEE VALLEYS. THIS WILL SHIFT EAST EARLY SATURDAY AND ALLOW A
COLD FRONT TO CROSS NORTHERN OHIO/PA SATURDAY EVENING. HIGH
PRESSURE RETURNS IN ITS WAKE FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE DROPPED THE REMAINING WIND ADVISORY WITH THE EARLY MORNING
UPDATE. REMAINING GUSTS THIS MORNING TO 40 MPH...BUT STRONGER
GUSTS ARE NO LONGER EXPECTED. EVEN DUNKIRK NY IS DOWN TO 40 KNOTS.
JUST A FEW HOURS AGO THEY STILL WERE GUSTING TO 50 KNOTS. PRESQUE
ISLE IS DOWN TO 30 KNOTS.
REALLY NOT A LOT OF COLD AIR BEHIND YESTERDAYS COLD FRONT AND THE
MAJORITY OF THE PRECIP ON THE BACKSIDE PULLED UP THROUGH MI AND
INTO CANADA. THEREFORE NO WHITE CHRISTMAS. STILL A FEW RAIN
SHOWERS OUT THERE EARLY THIS MORNING WITH THE UPPER TROUGH. MAY
SEE SOME WET SNOWFLAKES MIX IN AND ALSO MAY JUST SEE SOME PLAIN
DRIZZLE. TEMPERATURES WILL REMAIN ABOVE FREEZING. THE
PRECIPITATION CHANCES REALLY CONFINED TO THIS MORNING AS WE
QUICKLY TRANSITION TO RIDGING AND WARM ADVECTION. HIGHS FOR TODAY
WILL BE PRETTY MUCH WHERE THEY ARE AT RIGHT NOW...UPPER 30S WITH A
FEW IN THE LOWER 40S. MOSTLY CLOUDY...BUT WILL BE OPTIMISTIC FOR
SOME BREAKS ACROSS SOUTHWEST COUNTIES BEFORE SUNSET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
DRY CONDITIONS FOR TONIGHT THROUGH FRIDAY WITH HIGH PRESSURE
BUILDING ACROSS THE OHIO VALLEY. STILL RELATIVELY MILD WITH NO
SOURCE OF COLD AIR WITH THE WEST-SOUTHWEST FLOW. A SHORTWAVE EMERGES
FROM THE ROCKIES LONGWAVE TROUGH FRIDAY NIGHT TOWARD THE GREAT
LAKES REGION. SURFACE LOW PRESSURE WILL TRACK ACROSS THE LAKES
INTO CANADA AND TAKE A COLD FRONT ACROSS OH/PA SATURDAY NIGHT. AS
IT DOES SO...THE FRONT WILL SLOW AND WEAKEN WHILE THE RIDGE ACROSS
THE SOUTHEAST STATES HOLDS AND ONLY FLATTENS WITH TIME. IT WILL
TAKE SOME TIME ON SATURDAY TO BE ABLE TO GET PRECIP INTO NW OHIO.
WILL FOCUS THE MAJORITY OF THE PRECIP CHANCES ON SATURDAY NIGHT.
TEMPERATURES WILL STILL BE MILD SO EXPECTING THE MAJORITY OF THE
PRECIP TO FALL AS RAIN WITH SOME SNOW CHANCES WITH THE ADVANCING
COLD AIR TOWARD SUNDAY MORNING. TEMPERATURES CLOSER TO NORMAL FOR
SUNDAY. WILL LINGER SNOW SHOWER CHANCES INTO SUNDAY BUT HIGH
BUILDING IN MAY END THAT ALL TOGETHER. WILL KEEP CLOUDS AROUND
SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES FOR THE PERIOD WITH A
RIDGE BUILDING IN FROM THE NORTH. THE MODELS DISAGREE ON THE
MOISTURE. THE GFS IS VERY DRY FOR THE PERIOD WHILE THE ECMWF HAS
MUCH MORE MOISTURE FOR MONDAY THROUGH TUESDAY MORNING. BECAUSE OF
THAT KEPT CHANCE POPS FOR SNOW SHOWERS OVER NE OH AND NW PA AS THE
LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 16C. AS THE
RIDGE BUILDS IN LATER TUESDAY INTO WEDNESDAY THE FLOW BECOMES
SOUTHWEST SO WENT DRY ACROSS THE ENTIRE FORECAST AREA. WENT A LITTLE
COLDER THAN GUIDANCE MAINLY FOR THE HIGHS BASED ON THE FORECASTED
850 MB TEMPERATURES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A RIDGE WILL BE BUILDING INTO THE AREA TODAY. SOME WIDELY
SCATTERED RAIN AND SNOW SHOWERS WILL OCCUR THIS MORNING. OTHERWISE
MVFR CEILINGS WILL SLOWLY RISE. SOME QUESTION ON THE CLEARING FOR
TONIGHT. IT MAKES SENSE WITH THE RIDGE MOVING EAST OF THE AREA.
THE HRRR MODEL KEEPS THE LOW CLOUDS. DELAYED THE CLEARING OF THE
LOW CLOUDS A FEW HOURS...HOWEVER...SOME CIRRUS WILL BE ALOFT.
.OUTLOOK...NON-VFR LATE SATURDAY THROUGH SUNDAY NIGHT AND THEN
MAINLY OVER NE OH AND NW PA MONDAY THROUGH TUESDAY.
&&
.MARINE...
GALE FORCE WINDS WILL DIMINISH SOMEWHAT QUICKLY FROM THE WEST TODAY
AS WARM ADVECTION WILL BE STARTING AROUND DAYBREAK. WILL DOWNGRADE
THE GALE ON THE WEST END OF THE LAKE TO A SMALL CRAFT ADVISORY FOR
20 TO 25 KNOT WINDS THROUGH MID AFTERNOON. ON THE EAST END
CONTINUING THE GALE THROUGH 21Z/4PM TODAY AND THEN A SMALL CRAFT
ADVISORY WILL BE NEEDED AFTER THAT. THE FLOW ON THE LAKE WILL BECOME
SOUTHWEST TODAY AS A RIDGE BUILDS INTO THE OHIO VALLEY. ON FRIDAY
SOME QUESTION HOW STRONG THE SOUTHWEST WINDS WILL BE AND WHETHER A
SMALL CRAFT ADVISORY WILL BE NEEDED...ESPECIALLY ON THE EAST END.
THE WATER LEVEL HAS DROPPED BELOW THE CRITICAL MARK. SOME QUESTION
HOW LOW WILL IT GET WITH THE WINDS NOT THAT STRONG ON THE WEST END.
WILL NOT LET IT DROP BELOW 2 FEET BELOW THE CRITICAL MARK AND
THEN IT SHOULD SLOSH BACK ABOVE THE CRITICAL MARK BY NOON.
A FRONT WILL MOVE ACROSS THE LAKE LATE SATURDAY PROMPTING YET
ANOTHER THREAT FOR A SMALL CRAFT ADVISORY ON THE EAST END. BY SUNDAY
MORNING A RIDGE WILL BE OVER THE LAKE AND THE WINDS WILL DECREASE.
THE RIDGE WILL BE IN CONTROL OF THE WEATHER THROUGH TUESDAY...THUS
NOT EXPECTING THE NEED FOR A SMALL CRAFT ADVISORY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LEZ061-145>149-
165>169.
LOW WATER ADVISORY UNTIL NOON EST TODAY FOR LEZ142>144-162>164.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LEZ142>144.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
942 AM CST THU DEC 25 2014
.UPDATE...
FORECAST PACKAGE LOOKS ON TRACK FOR TEMPS AND DEWPOINTS. WENT
AHEAD AND UPDATED WIND AND WIND GUST GRIDS WITH LATEST RAP MODEL
AS IT WAS CAPTURING THE GUSTY WINDS ALREADY OBSERVED ON THE
ESCARPMENT AND NORTHERN HILL COUNTRY.
ALSO RE-RAN THE FIRE WX GRIDS USING LATEST MODEL DATA TO ADD SOME
PRECISION TO THE MIN RH VALUES. APPEARS THAT RH VALUES SHOULD STAY
ABOVE 20 PERCENT. WILL CONTINUE TO MONITOR CLOSELY.
TB3
&&
.PREV DISCUSSION... /ISSUED 549 AM CST THU DEC 25 2014/
AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THIS
EVENING. SURFACE SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING
CONTINUING THROUGH THE AFTERNOON AS MIXING TAKES PLACE AND A
SURFACE TROUGH PUSHES ACROSS NORTHWEST TEXAS. EXPECT GUSTS UP TO
25 KNOTS. LOW LEVEL MOISTURE WILL INCREASE TONIGHT AS SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST. WE ARE ANTICIPATING MVFR
CONDITIONS FOR ALL AREA TERMINALS OVERNIGHT AROUND 09Z AND 11Z
ACROSS KDRT. VFR CONDITIONS SHOULD RETURN BY 18Z FRIDAY.
PREV DISCUSSION... /ISSUED 336 AM CST THU DEC 25 2014/
SHORT TERM (TODAY THROUGH FRIDAY)...
UPPER AIR ANALYSIS LAST EVENING SHOWED A DEEP TROUGH EXTENDING
FROM THE GREAT LAKES TO EAST TEXAS WITH A RIDGE BUILDING UP
THROUGH THE ROCKIES. THERE WAS ANOTHER TROUGH EXTENDING FROM
WASHINGTON TO NORTHERN CALIFORNIA. WATER VAPOR SATELLITE IMAGERY
SHOWED MID-LEVEL DRY AIR OVER SOUTH CENTRAL TEXAS WITH MOISTURE
SPREADING INTO WEST TEXAS. AT THE SURFACE HIGH PRESSURE WAS
CENTERED ALONG THE COAST NEAR SOUTH PADRE ISLAND. THE PRESSURE
GRADIENT WAS NOT WELL DEFINED...BUT WINDS WERE TURNING TO THE WEST
AND SOUTHWEST. THE WEST COAST UPPER TROUGH WILL DIG DOWN INTO THE
SOUTHWEST AND THE UPPER FLOW OVER TEXAS WILL BECOME SOUTHWESTERLY.
BENEATH THIS TROUGH A FRONTAL SYSTEM WILL MOVE INTO WEST TEXAS
REACHING JUST NORTHWEST OF VAL VERDE COUNTY BY THE END OF THE
PERIOD. THE SURFACE HIGH WILL MOVE OUT INTO THE GULF AND LOW LEVEL
WINDS WILL BE SOUTHEASTERLY BRINGING WARM...MOIST AIR TO THE
REGION. THERE MAY BE SUFFICIENT ISENTROPIC LIFT FRIDAY TO PRODUCE
LIGHT RAIN OVER THE EASTERN COUNTIES. OTHERWISE THIS PERIOD WILL
BE WARM AND DRY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
MODELS SHOW THE UPPER TROUGH CONTINUING TO DIG SOUTH INTO MEXICO
INITIALLY...BUT THEN THERE ARE DIFFERENCES ON WHEN IT KICKS OUT TO
THE EAST. THEY ALL AGREE ON FRONTAL PASSAGE THROUGH OUR CWA FRIDAY
NIGHT AND SATURDAY MORNING. BEST MOISTURE WILL BE OVER THE EASTERN
HALF OF THE AREA...SO THAT IS WHERE THE BEST CHANCES FOR RAIN WILL
BE. MODELS DIFFER ON THE MOVEMENT OF THE UPPER TROUGH ACROSS TEXAS
SUNDAY. THE ECMWF IS FASTEST AND THE CANADIAN IS SLOWEST. WILL
LEAN TOWARD THE GFS WHICH IS IN THE MIDDLE. THIS WILL MEAN
CONTINUED CHANCES FOR RAIN SUNDAY. AFTER THIS TROUGH PASSES THE
UPPER PATTERN WILL BECOME ZONAL FOR THE FIRST PART OF NEXT WEEK
RETURNING DRY WEATHER FOR MONDAY. TUESDAY ANOTHER COLD FRONT WILL
MOVE INTO THE REGION. THIS WILL BRING ANOTHER SLIGHT CHANCE FOR
PRECIPITATION AND COLDER AIR. DEPENDING ON TIMING THERE IS A
CHANCE FOR SOME WINTER TYPE PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY MORNING OVER THE NORTHEASTERN PART OF THE FORECAST AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 63 52 68 55 59 / 0 - 10 20 40
AUSTIN BERGSTROM INTL AIRPORT 63 49 69 56 60 / 0 - 10 20 40
NEW BRAUNFELS MUNI AIRPORT 64 50 70 57 62 / 0 - 10 20 40
BURNET MUNI AIRPORT 60 49 65 49 52 / 0 - 10 20 40
DEL RIO INTL AIRPORT 63 44 65 46 60 / 0 0 - 10 10
GEORGETOWN MUNI AIRPORT 61 51 66 52 54 / 0 - 10 20 40
HONDO MUNI AIRPORT 64 45 68 52 60 / 0 - 10 20 30
SAN MARCOS MUNI AIRPORT 64 50 69 57 61 / 0 - 10 20 40
LA GRANGE - FAYETTE REGIONAL 64 53 71 59 64 / 0 - 20 30 40
SAN ANTONIO INTL AIRPORT 63 51 69 56 61 / 0 - 10 20 40
STINSON MUNI AIRPORT 64 50 70 56 62 / 0 - 10 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
618 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WAS MOVING EAST TOWARD THE COAST THIS MORNING. HIGH
PRESSURE OVER THE GULF COAST WILL THEN BUILD ACROSS THE EASTERN
UNITED STATES TODAY AND REMAIN OVER THE REGION THROUGH SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...
AT 4AM...COLD FRONT WAS JUST EXITING THE FAR EASTERN COUNTIES OF THE
FORECAST AREA. THE WESTERN EDGE OF THE FRONTAL PRECIPITATION
EXTENDED FROM CHARLOTTESVILLE TO DANVILLE. LATEST HRRR HAS THIS
PRECIPITATION EXITING THE EASTERN COUNTY WARNING AREA AROUND
10Z/5AM. WILL KEEP CHANCE OF SHOWERS IN THE WESTERN UPSLOPE AREAS
THIS MORNING. MOISTURE ABOVE 700 MB MOVES OUT OF THE FORECAST AREA
THIS MORNING ALONG WITH THE COLD FRONT. MODELS ERODE THE LOW LEVEL
MOISTURE THIS EVENING. WILL KEEP SOME CLOUD COVER IN THE NORTHWEST
THROUGH THIS EVENING. LOCATIONS TO THE EAST WILL CLEAR OUT THIS
MORNING.
SURFACE HIGH PRESSURE WAS OVER THE GULF COAST. THE HIGH MOVES ACROSS
THE SOUTHEAST UNITED STATES TODAY AND WILL BE CENTERED OVER THE
FORECAST AREA BY FRIDAY MORNING. SURFACE DEW POINTS DROP INTO THE
20S BY LATE TODAY. WITH THE DRY AIR MASS THAT WILL BE IN
PLACE...DIURNAL VARIATION IN TEMPERATURES WILL BE 20 TO 25 DEGREES.
EXPECT VALLEYS TO DECOUPLE THIS EVENING. WILL KEEP LOW TEMPERATURES
AT OR BELOW GUIDANCE TONIGHT.
MSAS SHOWED BEST PRESSURE RISES OVER THE GREAT LAKES EXTENDING INTO
NORTHERN VIRGINIA. 850 WINDS WILL BE AROUND 50 KNOTS FROM THE WEST
EARLY THIS MORNING...BUT WILL STEADILY DIMINISH TO BELOW 20 KNOTS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EST THURSDAY...
HIGH PRESSURE WILL KEEP THE REGION DRY THROUGH SATURDAY.
TEMPERATURES WILL MODERATE AS THE CENTER OF THE HIGH SHIFTS EAST AND
INCREASING SOUTHWEST WINDS USHER IN A WARM AIR ADVECTION PATTERN
ACROSS THE REGION.
SATURDAY NIGHT THROUGH SUNDAY NIGHT A BAROCLINIC ZONE WILL ESTABLISH
ITSELF FROM NEAR THE MISSISSIPPI DELTA NORTHEAST INTO THE LOWER OHIO
VALLEY. A SERIES OF DISTURBANCES WILL TRACK ALONG THIS
BOUNDARY AND BRING MULTIPLE PERIODS OF RAIN ACROSS THE FORECAST
AREA. CONFIDENCE IS LOW REGARDING TIMING AND TRACK OF EACH OF THESE
SYSTEMS BASED UPON THE GENEROUS SPREAD IN MODEL SOLUTIONS OF THE
FEATURES. HOWEVER...BY THE DAY SUNDAY...IT IS LIKELY THAT RAIN WILL
OCCUR DURING SOME PERIOD OF THE DAY TIME HOURS...AND LIKEWISE DURING
THE SUNDAY NIGHT PERIOD.
TEMPERATURES WILL BE ABOVE NORMAL DURING THIS PERIOD OF THE FORECAST.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
THE LARGE SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A
LITTLE COOLER THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE
TEMPERATURE FORECAST. WHILE I HAVE LOWERING POPS EACH
DAY...LARGELY DUE TO INCREASING UNCERTAINTY...AM KEEPING A LOW CHC
TO SLIGHT CHC IN THROUGH THE PERIOD WITH MORE INDICATION OF SOME
WINTRY PRECIP AS WE GET INTO TUES NIGHT AND WED.
OVERALL...FORECAST REALLY REFLECTS A VERY BROAD BRUSH RATHER THAN
GOING EXACTLY WITH ANY ONE SOLUTION...AND EXPECT THERE WILL BE
QUITE A FEW CHANGES TO THE EARLY WEEK FORECAST AS WE GET INTO THE
WEEKEND. NOT MUCH CHANCE FOR A MAJOR STORM DURING THIS
PERIOD...AND AFTER SUNDAY ITS POSSIBLE THAT DRY BUT COOL HIGH
PRESSURE MANAGES TO DOMINATE...BUT BEST GUESS FOR NOW IS SOMETHING
IN BETWEEN. AS ALWAYS...STAY TUNED!
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
COLD FRONT WAS WELL EAST OF THE REGION THIS MORNING AND RAIN HAS
MOVED OUT OF THE VIRGINIA AND NORTH CAROLINA FOOTHILLS. WINDS WILL
GUST FROM THE WEST UP TO 30 KNOTS BEHIND THE FRONT THIS MORNING.
THIS WILL COMBINE WITH LINGERING LOW LEVEL MOISTURE TO PRODUCE
MVFR CLOUDS IN KBLF AND KLWB AS WELL AS RAIN AND SNOW SHOWERS IN
THE MOUNTAINS.
HIGH PRESSURE OVER THE GULF COAST REGION WILL MOVE INTO THE AREA
TONIGHT...RESULTING IN DIMINISHING WINDS AND UPSLOPE CLOUDS. HIGH
CONFIDENCE THAT RAIN/SNOW SHOWERS WILL DISSIPATE BY 00Z TONIGHT
WITH THE CLOUDS OVER THE MOUNTAINS BECOMING SCATTERED THIS
EVENING. VFR CONDITIONS ARE EXPECTED FRIDAY.
EXTENDED DISCUSSION...
HIGH PRESSURE SHOULD BUILD OVER THE SOUTHEAST...WHICH WILL
PROVIDE VFR WEATHER WITH LIGHTER WINDS THROUGH FRIDAY NIGHT.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. BOUNDARY
MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT WEEK WITH
POSSIBLE RETURN TO VFR MONDAY AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
946 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST THU DEC 25 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CLOUD COVER/TEMPERATURES
FOLLOWED BY THE CHANCES FOR DRIZZLE/FREEZING DRIZZLE TONIGHT.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE IS ALIGNED ALONG THE
MISSISSIPPI RIVER AND DRIFTING EASTWARD AS A BROAD AREA OF LOW
PRESSURE DEVELOPS IN THE PLAINS. FURTHER ALOFT...THE MID LEVEL
FLOW IS FLATTENING OUT ACROSS THE NORTHERN PLAINS/UPPER
MISSISSIPPI RIVER VALLEY AS A TROUGH DIGS ACROSS THE ROCKIES. A
LOW LEVEL STRATUS DECK IS PRODUCING SOME SCATTERED FLURRIES DUE TO
THE TOP OF THE SATURATED LAYER/CLOUD DECK BEING AROUND -10C
ACCORDING TO IR SATELLITE. THIS IS COLDER THAN WHAT LOCAL SHORT
TERM SOUNDINGS SUGGEST IS OCCURRING. IR SATELLITE/OBS ACTUALLY
SHOW THE WESTERN EDGE OF IT RAPIDLY CLEARING IN ACROSS CENTRAL
IOWA/SOUTHWEST MINNESOTA AND IS TIMED TO BE MOVING THROUGH THE
REGION THIS MORNING INTO EARLY AFTERNOON WITH EROSION OCCURRING
FROM SOUTHWEST TO NORTHEAST. HOWEVER...HIGH LEVEL CLOUD COVER IS
QUICK ON ITS HEELS AND WILL LIMIT THE POTENTIAL OF SEEING ANY
SUNLIGHT UNLESS IT ENDS UP THINNING OUT AS IT APPROACHES. BASED
ON THE LOW CLOUDS CLEARING OUT...BUMPED UP FORECAST HIGH
TEMPERATURES A FEW DEGREES AS SURFACE WINDS COME AROUND TO THE
SOUTHWEST AND BRING SOME WARMER AIR INTO THE REGION.
GOING INTO TONIGHT THE QUESTION IS WITH WHETHER ANY
DRIZZLE/FREEZING DRIZZLE WILL OCCUR AS LOW LEVEL MOISTURE
TRANSPORT RAMPS UP INTO THE REGION. THE 25.00Z MODELS ARE ALL IN
AGREEMENT THAT A 30-40KT LOW LEVEL JET WILL DEVELOP ACROSS THE
SOUTHERN PLAINS THIS EVENING WITH IT NOSING NORTHEASTWARD AS THE
NIGHT PROGRESSES. FORECAST SOUNDINGS FROM THE NAM/GFS BOTH SHOW A
DEEPENING SATURATED LOW LEVEL LAYER WHICH IS NOT COLD ENOUGH TO
FORM ICE. THERE APPEARS TO BE SOME WEAK LIFT THANKS TO THE LLJ
NOSE/SURFACE BOUNDARY PROVIDING SOME CONVERGENCE. THE 25.00/06Z
NAM SURFACE REFLECTIVITY PANES SHOW THIS DRIZZLE DEVELOPING FROM
THE WEST OVERNIGHT...PARTICULARLY AFTER MIDNIGHT AND ALONG WHERE
THE CONVERGENCE IS IN THE SURFACE/LOW LEVELS. WITH THE SOUTHERLY
WINDS KEEPING THE WARMER AIR IN PLACE...THERE IS SOME QUESTION
ABOUT HOW COLD TEMPERATURES WILL BE AND WHETHER THE DRIZZLE WILL
BE FREEZING OR NOT. WILL HAVE TO MONITOR TRENDS...BUT WITH
TEMPERATURES AT OR JUST ABOVE FREEZING...EXPECT THAT THE IMPACT
WILL NOT BE THAT GREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU DEC 25 2014
GOING INTO THIS WEEKEND ON INTO THE MIDDLE OF NEXT WEEK...THE
FOCUS IS ON THE POTENTIAL FOR AN ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY FOLLOWED BY THE DRASTICALLY COLDER AIR MASS THAT
WILL SETTLE IN BY MIDWEEK.
EYES WILL BE ON THE MID LEVEL TROUGH DIGGING ACROSS THE
SOUTHWESTERN US AND HOW IT WILL EJECT INTO THE UPPER MIDWEST.
PREVIOUS MODEL RUNS HAD THIS WAVE COMING THROUGH AS MAINLY AN OPEN
TROUGH/SURFACE LOW BUT THE 25.00Z TRENDS WITH THE NAM/GFS/ECMWF
ARE TO GO DEEPER. THE ECMWF IS THE DEEPEST/SLOWEST WITH THIS
FEATURE AND BRINGS THE HEAVIEST SNOW TOTALS...POSSIBLY ADVISORY
WORTHY...ALONG WITH IT. ALL THREE MODELS ARE SHOWING A BAND OF
HEAVIER SNOW OCCURRING IN THE DEFORMATION AREA OF THE TROUGH WHICH
RUNS FROM SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. MOST
OF THE AREA SHOULD JUST SEE SNOW FROM THIS SYSTEM...BUT SOME
PORTIONS OF EASTERN IOWA AND SOUTHWEST WISCONSIN COULD BE WARM
ENOUGH TO CHANGE IT OVER TO RAIN. THE ECMWF TRENDS WILL HAVE TO BE
MONITORED BECAUSE IT WOULD SET US UP FOR SOME HIGHER SNOWFALL
TOTALS THAN CURRENTLY BEING FORECAST. WITH IT BEING A NEW
DIRECTION BEING TAKEN WITH THIS ONE MODEL...DECIDED IT WOULD BE
BEST TO JUST BLEND THAT SOLUTION WITH THE NAM/GFS IDEA TO COME UP
WITH SNOW ACCUMULATIONS OF 1 TO 3 INCHES. THE MAIN PERIOD TO WATCH
WILL BE SATURDAY MORNING AS THE ECMWF HAS AROUND 0.25 INCHES OF
QPF IN THAT PERIOD WHEN THE NAM/GFS ONLY HAS 0.01 INCHES OR SO.
BEYOND THIS SYSTEM IT LOOKS LIKE WE WILL HAVE AN EXTENDED PERIOD
OF HAVING A COLDER AIR MASS WHERE HIGHS ONLY GET INTO THE
TEENS...PARTICULARLY GOING INTO TUESDAY AND WEDNESDAY. PERHAPS THE
SILVER LINING HERE IS THAT WITH THIS COLD AIR AND A BROAD RIDGE OF
HIGH PRESSURE DROPPING DOWN ACROSS MUCH OF THE CENTRAL US...SKIES
SHOULD BE CLEAR WHICH WOULD BE WELCOME AFTER THIS EXTENDED PERIOD
OF OVERCAST CONDITIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 946 AM CST THU DEC 25 2014
946 AM UPDATE...LAST FEW MODEL RUNS OF THE RAP AS WELL AS TRENDS
IN OBSERVATIONS IN SOUTHEAST MINNESOTA HAVE SHOWN THAT THE STRATUS
REMAINS STUCK. AS SUCH...HAVE WENT MORE PESSIMISTIC WITH THE
FORECASTS AND HAVE HELD LOW CEILINGS IN PLACE FOR THE NEXT 24
HOURS. DID ALLOW RST TO CLIMB TO MVFR THIS AFTERNOON AS DAYTIME
HEATING HELPS. ADDITIONALLY...THERE APPEARS THERE COULD BE A BRIEF
SCATTERING OF THE CLOUDS AT LSE BETWEEN 21-01Z...WHICH HAVE BEEN
HONORED WITH A TEMPO GROUP.
541 AM DISCUSSION...
CURRENTLY WATCHING BACK EDGE OF IFR/MVFR STRATUS ACROSS SOUTH
CENTRAL MN INTO EASTERN IA ERODING NORTHEASTWARD TOWARD THE
KRST/KLSE TAF SITES. EXPECTING KRST TO BREAK OUT OF STRATUS BY
15Z AND KLSE BY 17Z. AS THIS CLEARS OUT...LOOK FOR ALTOCUMULUS TO
SPREAD IN FROM THE WEST AHEAD OF A WEAK AREA OF LOW PRESSURE OVER
THE PLAINS. AS THIS LOW CLOSES IN ON THE REGION TONIGHT...PLAN ON
A RETURN OF MVFR STRATUS BETWEEN 03-05Z. KRST LOOKS TO DIP INTO
IFR AFTER 09Z. WITH THE RETURN OF THIS STRATUS AND WEAK
LIFT...EXPECTING PATCHY LIGHT FREEZING DRIZZLE TO DEVELOP AFTER
MIDNIGHT. FEEL THIS DRIZZLE WILL BE HIT AND MISS...SO OPTED NOT TO
INCLUDE IN THE BODY OF THE TAFS AT THIS POINT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS/AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
340 PM MST THU DEC 25 2014
.SYNOPSIS...EXPECT BREEZY TO WINDY CONDITIONS EARLY THIS EVENING
FOLLOWED BY A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT.
THE BEST CHANCE OF PRECIPITATION WILL BE SOUTHEAST OF TUCSON. A FEW
LINGERING SHOWERS WILL OCCUR ACROSS EASTERN SECTIONS FRIDAY...THEN
DRY CONDITIONS WILL PREVAIL THIS WEEKEND AND EARLY NEXT WEEK.
WIDESPREAD FREEZING TEMPERATURES WILL PREVAIL FRIDAY NIGHT...AND A
HARD FREEZE MAY OCCUR ACROSS THE TUCSON METRO AREA.
&&
.DISCUSSION...SHOWERS HAVE YET TO DEVELOP WEST OF TUCSON AT THIS
TIME AS HAS BEEN CONSISTENTLY ADVERTISED VIA VARIOUS NWP MODELS.
HOWEVER...CLOUDS CONTINUE TO THICKEN ACROSS CENTRAL PIMA COUNTY AND
SRN PINAL COUNTY. HAVE NOTED THAT THE LATEST RUC HRRR DEVELOPS LIGHT
PRECIP ECHOES SW OF TUCSON BY 5 PM MST FOLLOWED BY AN EXPANSIVE AREA
OF PRECIP ECHOES...SOME PERHAPS THAT MAY PRODUCE HEAVY RAINFALL...
FROM THE FAR SRN PORTIONS OF THE TUCSON METRO AREA SWWD INTO SOUTH
CENTRAL PIMA COUNTY EARLY THIS EVENING. THE BULK OF THESE ECHOES ARE
THEN PROGGED TO MOVE SEWD MAINLY ACROSS COCHISE/SANTA CRUZ COUNTIES
LATER THIS EVENING.
AT ANY RATE...HAVE CONTINUED WITH A GOOD CHANCE OF VALLEY RAIN/
MOUNTAIN SNOW SHOWERS MOSTLY FROM TUCSON EWD/SWD THIS EVENING. HAVE
ENDED PRECIP FROM TUCSON WWD LATE TONIGHT...BUT HAVE KEPT SCATTERED
TO NUMEROUS SHOWERS ACROSS ERN SECTIONS. A SLIGHT CHANCE OF SHOWERS
WILL CONTINUE ACROSS ERN SECTIONS FRI MORNING...AND A FEW LINGERING
SHOWERS MAY YET CONTINUE NEAR THE NEW MEXICO BORDER FRI AFTERNOON.
STORM TOTAL LIQUID AMOUNTS AND SNOW ACCUMULATIONS REMAIN UNCHANGED.
THUS...LIQUID AMOUNTS WILL GENERALLY RANGE BETWEEN ONE TENTH OF AN
INCH AND ONE THIRD OF AN INCH...WITH SNOW ACCUMULATIONS OF 2-5
INCHES ABOVE 7000 FEET.
DRY CONDITIONS WILL THEN PREVAIL STARTING FRI EVENING AND CONTINUE
THRU TUE. THE FOCUS OF ATTENTION WILL THEN TURN TOWARD THE NEXT
DEEPENING UPPER TROUGH AND CLOSED LOW OVER THE SWRN CONUS BY THE
MIDDLE OF NEXT WEEK. 25/12Z GFS/ECWMF/CMC WERE IN GOOD AGREEMENT
THAT THIS SYSTEM WILL BRING ANOTHER CHANCE OF VALLEY RAIN/MOUNTAIN
SNOW...ESPECIALLY WED NIGHT AND NEW YEARS DAY. HAVE MAINTAINED A
SLIGHT CHANCE OF SHOWERS ACROSS THE HIGHER TERRAIN EAST OF TUCSON
TUE NIGHT. THERE IS A SLIGHT CHANCE OF VALLEY RAIN/MOUNTAIN SNOW
SHOWERS WED...AND POPS WERE INCREASED WED NIGHT INTO THE CHANCE-
CATEGORY ACROSS ERN SECTIONS. A CHANCE OF MOUNTAIN SNOW SHOWERS WILL
CONTINUE EAST OF TUCSON NEXT THUR...WITH A SLIGHT CHANCE OF SHOWERS
AS FAR WEST AS TUCSON. THIS SYSTEM HOLDS THE POTENTIAL TO PRODUCE
SNOW LEVELS AS LOW AS THE VALLEY FLOORS ACROSS COCHISE COUNTY AND
GRAHAM COUNTY.
FINALLY...A FREEZE WARNING WAS ISSUED FOR MUCH OF PIMA COUNTY AND
SRN PINAL COUNTY LATE FRIDAY NIGHT INTO EARLY SAT MORNING. THE
POTENTIAL EXISTS FOR A HARD FREEZE TO OCCUR ACROSS MUCH OF THE
TUCSON METRO AREA...AT LEAST FOR A FEW HOURS. THUS...THIS FREEZE
WARNING WILL POSSIBLY BE MODIFIED FOR A HARD FREEZE WARNING...
PARTICULARLY FOR ERN PIMA COUNTY INCLUDING TUCSON. OTHERWISE...
DAYTIME TEMPS FRI-SAT WILL BE WELL BELOW SEASONAL NORMALS FOLLOWED
BY A WARMING TREND SUN-MON. EXPECT NEAR NORMAL HIGH TEMPS TUE...
THEN MUCH COOLER TEMPS WILL RETURN WED-THUR.
&&
.AVIATION...VALID THRU 26/23Z.
A LOW PRESSURE SYSTEM MOVING ACROSS THE FOUR CORNERS REGION WILL
RESULT IN SCATTERED TO NUMEROUS -SHRA AND HIGHER TERRAIN -SHSN THIS
EVENING AND TONIGHT...MAINLY FROM TUCSON EASTWARD. SCT-BKN CLOUDS AT
4-7K FT AGL. MVFR CONDITIONS WILL OCCUR AT TIMES...ESPECIALLY ACROSS
HIGHER TERRAIN. ISOLATED -SHRA AND HIGHER TERRAIN -SHSN WILL PREVAIL
EAST OF TUCSON FRIDAY MORNING. SURFACE WIND WILL GENERALLY BE
SWLY/WLY AT 15-30 KTS WITH GUSTS TO AROUND 40 KTS THRU 26/02Z.
DIMINISHING SURFACE WIND THIS EVENING AND TONIGHT...WITH SURFACE
WIND LESS THAN 15 KTS BY 26/10Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...A STRONG STORM SYSTEM WILL MOVE THROUGH THE FOUR
CORNERS AREA TONIGHT...AND EAST OF THE REGION ON FRIDAY. BREEZY TO
WINDY CONDITIONS WILL PERSIST INTO THE EARLY EVENING HOURS TONIGHT
BEFORE DIMINISHING. LESS WIND IS EXPECTED OVER THE WEEKEND. THERE
WILL BE A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT. A
CONTINUED SLIGHT CHANCE OF SHOWERS WILL OCCUR MAINLY NEAR THE NEW
MEXICO BORDER FRIDAY...FOLLOWED BY DRY CONDITIONS THIS WEEKEND AND
EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ503-507-508-
512-513.
FREEZE WARNING FROM MIDNIGHT FRIDAY NIGHT TO 9 AM MST SATURDAY
FOR AZZ501-502-504>506.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...ZELL
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
909 AM MST THU DEC 25 2014
.SYNOPSIS...
A SOMEWHAT DRY LOW PRESSURE SYSTEM WILL SLIDE THROUGH THE AREA TODAY
BEFORE SLOWING AND LINGERING OVER THE FOUR CORNERS THROUGH THE
WEEKEND. THIS SYSTEM WILL BRING COOLER AND BREEZY CONDITIONS ALONG
WITH A CHANCE OF SOME LIGHT SHOWERS...AND POSSIBLY A LIGHT DUSTING OF
SNOW...OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA THIS
AFTERNOON AND EVENING INTO FRIDAY. A DRY AND CONTINUED COOL WEATHER
PATTERN WILL PERSIST FROM THROUGH EARLY NEXT WEEK.
&&
.DISCUSSION...
MID MORNING WATER VAPOR IMAGERY REVEALS LOW PRESSURE OVER UTAH WITH
A SHORTWAVE TROUGH EXTENDING SOUTHWARD THROUGH PORTIONS OF
ARIZONA...SOUTHEAST NEVADA...AND SOUTHEAST CALIFORNIA. A SURFACE
COLD/COOL FRONT IS POSITIONED ROUGHLY FROM FLAGSTAFF TO LAKE HAVASU
AS OF 16Z WITH SOME LIGHT SHOWERS NOTED ON RADAR ACROSS NORTHERN
ARIZONA. ACROSS THE LOWER AZ DESERTS...CONDITIONS REMAIN DRY BUT
CLOUDS ARE INCREASING JUST A BIT AHEAD OF THE FRONT.
IN THE SHORT TERM...THE FRONT WILL MOVE THROUGH THE AREA RELATIVELY
QUICKLY...A BIT FASTER THAN MODELS HAD PREVIOUSLY INDICATED...AND
COULD VERY WELL BE EXITING THE STATE BY EARLY EVENING. LATEST HI-RES
GUIDANCE INCLUDING THE HRRR AND LOCAL WRFS SUGGEST A FEW SHOWERS
DEVELOPING EARLY THIS AFTERNOON IN THE HIGHER TERRAIN LOCATIONS
NORTH/EAST OF PHOENIX...WITH MORE COVERAGE ACROSS PORTIONS OF
SOUTHEAST ARIZONA. ACROSS THE PHOENIX AREA...ANY SHOWERS THAT
DEVELOP WOULD BE WIDELY SCATTERED AT BEST AND WOULD BE VERY SHORT
LIVED. THE INHERITED FORECAST OF 10 POPS ACROSS THE METRO STILL
SEEMS VALID WITH 30-40 POPS CERTAINLY WARRANTED EAST OF PHOENIX. I
TRIMMED THINGS BACK JUST A BIT AFTER 06Z AS THE FRONT SHOULD BE WELL
SOUTH/EAST OF THE AREA BY THEN AND DRIER AIR SHOULD BE MOVING IN
FROM THE NORTH.
IN TERMS OF SNOWFALL...IT WILL BE A RACE BETWEEN HOW QUICKLY THE
COLDER AIR MOVES INTO PLACE VS HOW QUICKLY THE PRECIPITATION EXITS
THE AREA. SNOW LEVELS ARE EXPECTED TO FALL BELOW 5000 FEET THIS
AFTERNOON ALTHOUGH GIVEN THE RAPID NATURE OF THE FRONT...PRECIP
SHOULD BE COMING TO AN END RIGHT AROUND THE SAME TIME. COULD BE A
BRIEF MIX OF RAIN/SNOW WITH LITTLE TO NO ACCUMULATION ABOVE 5000FT
THIS AFTERNOON/EARLY EVENING BUT THAT`S ABOUT IT. NO MAJOR
WINTER-TYPE CONCERNS EXPECTED WITH THIS SYSTEM.
FINALLY...THERE SHOULD BE SOME BREEZINESS COINCIDENT WITH THE
FRONTAL PASSAGE LATER THIS AFTERNOON...GENERALLY IN THE 10-20MPH
RANGE WITH OCCASIONAL HIGHER GUSTS ON THE RIDGES NORTH/EAST OF
PHOENIX. OVERALL THE FORECAST IS IN GOOD SHAPE. LOOK FOR HIGHS TO
REACH THE LOWER 60S THIS AFTERNOON...ABOUT 2-3 DEGREES BELOW NORMAL
FOR LATE DECEMBER. SHOULD BE A CHILLY NIGHT ESPECIALLY IN THE
PROTECTED AREAS OF LA PAZ COUNTY AND THE LOW LYING AREAS NEAR THE
COLORADO RIVER WHERE THE WINDS CALM DOWN AFTER SUNSET. EVEN COLDER
TEMPERATURES ARE EXPECTED FRIDAY/FRIDAY NIGHT.
&&
.PREVIOUS DISCUSSION...
FRIDAY MORNING INTO EARLY NEXT WEEK...
UPPER TROUGHING WILL LINGER OVER THE FOUR CORNERS AS THE JET STREAM
DIPS FURTHER TO OUR SOUTH FRIDAY. CLEAR SKIES AND LIGHTER WINDS WILL
TAKE FULL ADVANTAGE OF THE COOLER AIRMASS BEHIND THE FRONT AND RESULT
IN SOME OF OUR COOLEST MORNINGS SO FAR THIS LATE FALL/WINTER FOR
FRIDAY AM AND THE COMING WEEKEND. DAYTIME TEMPERATURES FRIDAY COULD
BE ANYWHERE FROM 8 TO 10 DEGREES BELOW SEASONAL NORMALS WITH
WIDESPREAD 50S ACROSS THE LOWER DESERTS. FRIDAY NIGHT HAS THE
POTENTIAL TO BRING FREEZING TEMPERATURES TO NORTHERN PINAL
COUNTY...INCLUDING THE FAR SOUTHEAST AND WESTERN FRINGES OF THE
PHOENIX METRO...AS WELL AS RURAL AREAS OF SOUTHWEST ARIZONA. HIGH
TEMPERATURES FOR THE WEEKEND COULD STRUGGLE TO BREAK INTO THE 60S
ACROSS MANY OF THE LOWER DESERT LOCALES WITH OVERNIGHT LOWS DIPPING
INTO THE 30S...AND BRIEFLY THE UPPER 20S...IN SPOTS. IN ANTICIPATION
OF THE UPCOMING COLD MORNINGS...A SPECIAL WEATHER STATEMENT (SPSPSR)
HAS BEEN ISSUED FOR LA PAZ CO. FOR FRIDAY MORNING AND A FREEZE
WARNING HAS BEEN ISSUED FOR SATURDAY MORNING ACROSS LA PAZ...NW
MARICOPA...AND NW PINAL COUNTIES.
TAKING A BROAD BRUSH APPROACH FROM THE WIDELY VARYING MODEL FCST FOR
THE EXTENDED...MOSTLY DRY AND COOL NORTHWEST FLOW WITH EMBEDDED
SHORTWAVES WILL HOLD OVER THE REGION FOR EARLY NEXT WEEK...KEEPING
TEMPERATURES AT OR BELOW SEASONAL NORMALS WHILE PERIODICALLY BRINGING
CLOUDS INTO THE REGION. 00Z OPERATIONAL SOLNS FROM THE GFS/ECMWF/GEM
ALL ADVERTISE A LARGE UPPER LOW DEVELOPING INTO THE SW STATES WITH
CONSIDERABLE MOISTURE FIELDS AND QPF VALUES BY TUESDAY.
MEANWHILE...ONLY A SMALL PERCENTAGE OF ENSEMBLE MEMBERS SUPPORT
THEIR OPERATIONAL COUNTERPARTS. FOR NOW...MAINTAINED A COOL FORECAST
FOR BOTH HIGHS AND LOWS AND BLENDED INTO CLIMO POP INFLUENCE IN THE
EXTENDED FOR TUESDAY AND BEYOND.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A COLD FRONT WILL PASS THROUGH THE PHOENIX TERMINALS AROUND 18Z
CAUSING A RATHER ABRUPT WIND SHIFT. WHILE A BRIEF HIGHER GUST MAY BE
POSSIBLE...SPEEDS SHOULD LARGELY REMAIN BELOW 15KT. COINCIDENT WITH
FROPA...A RATHER NARROW BAND OF CIGS IN A 5K-8K AGL WILL AFFECT THE
AERODROME SPACE WITH SOME ACCOMPANYING VIRGA. THERE IS MODERATE
CONFIDENCE CIGS WILL ONLY PREVAIL FOR A COUPLE HOURS AND REMAIN
MOSTLY ABOVE 6K FT...BUT SOME PARTIAL MOUNTAIN OBSCURATION MAY BE AN
IMPACT. RAPID CLEARING BY SUNSET WILL YIELD NO AVIATION CONCERNS
OVERNIGHT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
A COLD FRONT WILL PASS THROUGH SOUTHEAST CALIFORNIA THIS MORNING
CAUSING A PERIOD OF GUSTY WINDS. THE INITIAL POST FRONTAL PRESSURE
PACKING HAS CAUSED GUSTS OVER 35KT AT KIPL...THOUGH THESE SPEEDS
SHOULD DECREASE RAPIDLY WHILE THE DIRECTION TURN MORE TO THE N/NW
THROUGH THE MORNING. OTHERWISE...PERSISTENT HIGHER GUSTS NEAR 25 KT
WILL PREVAIL INTO THE LATE AFTERNOON. SOME RESIDUAL MOISTURE BEHIND
THE FRONT MAY CAUSE A BRIEF PERIOD OF CIGS IN A 5K-7K AGL...BUT
THESE CIGS SHOULD BE SHORT LIVED. WIND SPEEDS WILL DECREASE BY
SUNSET WITH NO AVIATION IMPACTS OVERNIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
TRANQUIL DRY AND ABNORMALLY COOL WEATHER WILL PREVAIL OVER THE
WEEKEND INTO EARLY NEXT WEEK WITH NO FIRE WEATHER CONCERNS. ONLY A
BRIEF PERIOD OF SOMEWHAT GUSTY WINDS DOWN THE COLORADO RIVER VALLEY
WILL DISRUPT OTHERWISE NEARLY CALM CONDITIONS. AFTERNOON HUMIDITY
VALUES WILL ONLY FALL INTO A 20 TO 30 PERCENT RANGE WITH GOOD TO
EXCELLENT OVERNIGHT RECOVERY. THE POTENTIAL EXISTS FOR ANOTHER WIND
PRODUCING AND WETTER WEATHER SYSTEM AFFECTING THE DISTRICT BY THE
MIDDLE OF NEXT WEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING FROM MIDNIGHT FRIDAY NIGHT TO 8 AM MST SATURDAY
AZZ021-022-028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/NOLTE
AVIATION...MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
929 AM MST THU DEC 25 2014
.UPDATE...
ISSUED AT 929 AM MST THU DEC 25 2014
HAVE REINITIALIZED THE FORECAST GRIDS WITH THE LATEST
OBSERVATIONS. FRONTAL PUSH HAS BEGUN TO DROP INTO NORTHERN
COLORADO WITH SNOW ALREADY BEING REPORTED IN CHEYENNE. SOME DRYING
IS MOVING IN WITH THE SOUTHWEST FLOW ALOFT WHICH IS CLEARING
SKIES OVER MOST OF THE AREA EXCEPT FAR NORTHERN COLORADO. HOWEVER
WITH THE FRONT PUSHING DOWN AND UPSLOPE FLOW INCREASING...EXPECT
THE NORTHERN FRONT RANGE TO INCREASE IN CLOUD COVER OVER THE
COUPLE HOURS. A SECONDARY PUSH IS STILL SHOWN IN THE MODELS AROUND
5 PM TONIGHT WITH STRONGER WINDS AND BETTER MOISTURE...WHICH WILL
LIKELY BRING THE HEAVIER SNOWFALL. THIS STILL LINES UP WELL WITH
THE CURRENT HIGHLIGHTS...SO WILL NOT ADJUST ANYTHING AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 346 AM MST THU DEC 25 2014
AN UPPER LEVEL LOW WILL CLOSE OFF OVER UTAH TODAY AND THEN MOVE INTO
THE FOUR CORNERS AREA BY LATE TONIGHT. AT THE SFC LOW PRES WILL
INTENSIFY JUST SOUTH OF DENVER THRU THE AFTN AND THEN MOVE SE INTO
SERN CO BY EARLY THIS EVENING. MEANWHILE A SURGE OF COOLER AIR WILL
GRADUALLY MOVE INTO NERN CO THRU THE DAY WITH INCREASING UPSLOPE
FLOW NORTH OF THE BNDRY LATER THIS AFTN INTO THE EVENING HOURS.
MEANWHILE WILL SEE SOME MID LVL ASCENT ACROSS THE AREA LATER THIS
AFTN INTO TONIGHT WITH DIFFLUENT FLOW ALOFT. SNOW WILL INCREASE IN
THE MTNS THIS AFTN AND AT LOWER ELEVATIONS NR THE WY BORDER BY 21Z
WITH ADDITIONAL DEVELOPMENT SPREADING SOUTH ACROSS THE NRN FOOTHILLS
AND IN AREAS FROM FORT COLLINS TOWARDS BOULDER. AM SOMEWHAT
CONCERNED WITH INCREASING ENE FLOW AND POTENTIAL FOR HEAVIER
SNOWFALL IN ZNS 38 AND 39 FOR THIS EVENING ALONG AND WEST OF I-25.
LATEST RAP IS SHOWING INCREASING POTENTIAL FOR 6 TO 8 INCHES OVER A
3 TO 4 HOUR PERIOD FROM 23Z TO 03Z. THUS WILL UPGRADE ADVISORY TO A
WARNING FOR THESE AREAS. FURTHER SOUTH OVER DENVER HEAVIER SNOW MAY
ALSO DEVELOP OVER THE WRN SUBURBS AT SOME POINT WITH SOME POTENTIAL
FOR WARNING CRITERIA LATER THIS EVENING HOWEVER OVERALL CONFIDENCE
IS NOT AS HIGH SO WILL KEEP CURRENT ADVISORY IN PLACE.
OVER THE PLAINS WILL SEE SNOW GRADUALLY DEVELOP THIS EVENING WITH
ADVISORY AMOUNTS POSSIBLE IN SOME AREAS. WINDS WILL NOT BE REAL
STRONG HOWEVER WILL PROBABLY SEE SOME REDUCED VISIBILITIES AT
TIMES. IN THE MTNS AND FOOTHILLS WILL KEEP PREVIOUS HIGHLIGHTS
INTACT ALTHOUGH SRN FOOTHILLS AND PALMER DIVIDE MAY NOT SEE
HEAVIER SNOWFALL UNTIL AFTER 03Z.
FOR LATER TONIGHT AROUND MIDNIGHT SNOW INTENSITIES MAY BEGIN TO
DECREASE HOWEVER WILL LIKELY SEE AREAS OF STEADIER LIGHT SNOW
THROUGH SUNRISE IN MOST AREAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MST THU DEC 25 2014
ON FRIDAY...THE UPPER TROUGH WILL BE IN THE VICINITY OF THE FOUR
CORNERS AT 12Z...IT WILL GRADUALLY OPEN UP AND SHIFT EASTWARD
THROUGH THE DAY. THE TROUGH AXIS ITSELF IN PROGGED TO SHIFT TO THE
EAST OF COLORADO BY FRIDAY EVENING. WEAK QG ASCENT WILL BE PRESENT
FRIDAY MORNING...THEN DECREASE THROUGH THE REST OF THE DAY.
ADDITIONAL ACCUMULATIONS ON FRIDAY WILL BE LIGHT...MAYBE ANOTHER 1
TO 4 INCHES IN THE HIGH COUNTRY...AND ANOTHER 1 TO 2 INCHES OVER
THE NORTHEAST PLAINS. A DRIER NORTHWEST TO WESTERLY FLOW ALOFT
WILL DEVELOP LATE FRIDAY NIGHT INTO SATURDAY. LINGERING MOISTURE
AROUND FRIDAY NIGHT SO WL KEEP CHC POPS IN THE MOUNTAINS. MAIN
ADJUSTMENT TO THE GRIDS ON FRIDAY AND FRIDAY NIGHT WAS TO SLOW THE
TIMING A BIT. SATURDAY AND SATURDAY NIGHT...A SHORT WAVE RIDGE
WILL BE OVER THE REGION WITH THE FLOW ALOFT INCREASING AHEAD OF
THE NEXT SYSTEM IN THE PACIFIC NORTHWEST. MOISTURE WILL INCREASE
OVER THE MOUNTAINS BY SUNDAY AFTERNOON WITH INCREASING MID AND
UPPER LEVEL QG ASCENT DEVELOPING AS THE TROUGH MOVES INTO SRN
ID/SWRN WY. THE MDLS KEEP THE TROF AXIS TO THE NORTH AND WEST OF
COLORADO SUNDAY NIGHT WITH A 100 KT WEST TO EAST UPPER JET
TRANSLATING SOUTHWARD ACROSS THE STATE. COULD SEE SOME ENHANCED
CSI BANDS DEVELOP AS WE SLIP TO THE NORTHERN SIDE OF THE JET MAX.
WL GO WITH LIKELY POPS IN THE MOUNTAINS...AND AGAIN SOME
HIGHLIGHTS MAY NEED TO BE POSTED AT SOME POINT. AN ARCTIC COLD
FRONT WILL MOVE INTO THE FRONT RANGE SUNDAY NIGHT INTO MONDAY
MORNING. TEMPERATURES ON MONDAY WL ONLY REACH THE UPPER TEENS. WL
GO WITH CHC POPS AS WELL. ALTHOUGH TIMING WL AGAIN BE AN
ISSUE...WL GO WITH THE TREND OF DRIER BUT CONTINUED COLD FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 929 AM MST THU DEC 25 2014
STILL LOOKS AT THIS TIME THAT EVEN THOUGH LIGHT SNOW MAY BEGIN MID
AFTERNOON AT KDEN AND KBJC...IT APPEARS BEST CHANCE FOR HEAVIER SNOW
WILL HOLD OFF UNTIL AFTER 5 PM WITH A SECONDARY COLD PUSH. THEN
EXPECT AN INCREASE IN COVERAGE AND INTENSITY THRU THE EARLY
EVENING HOURS AS IT PUSHES DOWN TO KAPA. SNOW INTENSITY WILL
DECREASE BY MIDNIGHT...BUT WILL CONTINUE TO SEE LIGHT SNOW THRU
SUNRISE. RIGHT NOW WILL GO WITH ACCUMULATIONS IN THE 3 TO 5 INCH
RANGE FOR DIA...5 TO 8 INCH RANGE FOR KBJC AND KAPA FROM 5 PM
THRU 5 AM.
AS FOR WINDS...OVERALL CONFIDENCE IS NOT THAT HIGH FOR LATER THIS
MORNING THRU THE AFTN. THE FIRST INITIAL PUSH HAS COME THROUGH THE
AIRPORTS TO SWITCH THEM TO THE NORTHWEST. LATEST HRRR AND RAP
HAVE HAD VERY DIFFERENT SOLUTIONS FOR THE WIND FIELDS AROUND THE
AIRPORT AS THE LOW PUSHES SOUTH. WITH NORTHWEST WINDS SHOWING
UP...IT SEEMS AS THE RAP HAS THE BETTER HANDLE ON THE SITUATION.
WILL SWITCH THE WINDS TO THE NNW THEN WILL HAVE THEM SLOWLY BACK
TO THE NE OR E BEFORE THE SECOND NORTHERLY PUSH IS EXPECTED
AROUND 01Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ035-036-039.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ031-033-034.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 8 AM MST FRIDAY
FOR COZ038.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM MST
FRIDAY FOR COZ042-043.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ040-045-046.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ041.
&&
$$
UPDATE...KRIEDERMAN
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
116 PM EST THU DEC 25 2014
.SYNOPSIS...
HIGH PRESSURE BUILDS OVER THE SOUTHEASTERN U.S. THROUGH SATURDAY. A
COLD FRONT CROSSES THE TRI-STATE ON SUNDAY. THIS FRONT STALLS OUT
WELL TO THE SOUTH OF LONG ISLAND...AS COLD CANADIAN HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WELL...PANCAKE STRATO-CU HAS FILLED A LOT MORE THAN EXPECTED. THE
SUN WAS NICE WHILE IT LASTED. NARRE-TL HAD NO CLUE ON THESE CLOUDS
AS SEEN IN RAP AND HRRR SOUNDINGS UNDER ESTIMATING SATURATION AT
THE BASE OF THE INVERSION. EXPECT THE CLOUDS TO MIX OUT WITH LOSS
OF SURFACE HEATING STARTING IN THE NEXT 1-2 HOURS AS LAYER IS
THIN.
TEMPERATURES SLOWLY FALL OFF FROM HERE INTO LATE AFTERNOON.
WINDS GUSTS TO 30-40 MPH CONTINUE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
GUSTY WINDS LAST INTO EARLY THIS EVENING...THEN FAIRLY RAPIDLY
DIMINISH THROUGH THE REMAINDER OF THE EVENING.
DEEP LAYERED RIDGING BEGINS TO BUILD IN TONIGHT...WITH ITS AXIS
BUILDING OVER THE AREA ON SATURDAY...THEN SLIDING OFF TO THE EAST
SATURDAY NIGHT. ASSOCIATED SUBSIDENCE UNDER THE RIDGE SHOULD KEEP
THINGS DRY FROM THURSDAY NIGHT-SATURDAY NIGHT...WITH MINIMAL CLOUD
COVER THROUGH SATURDAY...THEN INCREASING MID-HIGH CLOUDS AHEAD OF
A COLD FRONT SATURDAY NIGHT.
FOR LOWS TONIGHT...USED A BLEND OF ECS/MAV/MET GUIDANCE WITH NAM
2-METER TEMPERATURES...WITH VALUES FORECAST TO BE AROUND 10
DEGREES ABOVE NORMAL. A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM
2-METER TEMPERATURES AND A MIX DOWN FROM 975-950 HPA PER BUFKIT
SOUNDINGS WAS USED FOR HIGHS ON FRIDAY...WITH READINGS EXPECTED TO
BE 5-10 DEGREES ABOVE NORMAL.
FOR LOWS FRIDAY NIGHT A BLEND OF MAV/MET GUIDANCE WAS USED...WITH
VALUES AROUND 10-15 DEGREES ABOVE NORMAL. FOR HIGHS SATURDAY A
BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX
DOWN FROM 975 HPA PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD BE
AROUND 10 DEGREES ABOVE NORMAL. A BLEND OF MEX/MEN/EKD/ECM/ECE/WPC
GUIDANCE WITH NAM 2-METER TEMPERATURES WAS USED FOR LOWS SATURDAY
NIGHT...WITH VALUES FORECAST TO BE 10-15 DEGREES ABOVE NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
WITH EXCEPTION OF 24/12Z CMC GPDS - MODELS REMAIN FAIRLY GOOD
AGREEMENT WITH THE IDEA THAT THE COLD FRONT THAT PASSES THROUGH
THE AREA SUNDAY...ENDS UP STALLING OUT TO FAR TO THE SOUTH. LOW
PRESSURE PASSING ALONG THE FRONT HAVE LITTLE, IF ANY, IMPACT ON
THE AREA. TWO POSSIBLE EXCEPTIONS ARE WITH THE INITIAL WAVE OF LOW
PRESSURE AND SECONDARY COLD FRONTAL PASSAGE SUNDAY NIGHT...AND
ANOTHER WAVE OF LOW PRESSURE ON TUESDAY.
FOR NOW...HAVE SLIGHT CHANCE TO CHANCE POPS WITH THE COLD FRONTAL
PASSAGE...THEN SLIGHT CHANCE POPS ACROSS SOUTHERN ZONES WITH THE
PASSAGE OF THE FIRST WAVE. FOR NOW IT APPEARS THE BOUNDARY LAYER
SHOULD BE WARM ENOUGH TO SUPPORT ONLY RAIN IN THIS TIME FRAME.
THE REGION REMAINS IN BETWEEN A CLOSED UPPER LOW TO THE N AND
RIDGING OFF THE FL COAST THROUGH AT LEAST TUESDAY NIGHT...WITH THE
TIMING AND PLACEMENT OF SHORTWAVE TROUGHS EMBEDDED IN THE FLOW
BETWEEN THE TWO DETERMINING THE EXACT TRACK/STRENGTH OF WAVES OF
LOW PRESSURE ALONG THE STALLED COLD FRONT. FOR NOW APPEARS
STRONGEST SHORTWAVE WILL PASS ON TUESDAY...SO HAVE SLIGHT CHANCE
POPS ACROSS SOUTHERN AREAS MONDAY NIGHT/TUESDAY...OTHERWISE HAVE
GONE DRY OVER LAND MONDAY- TUESDAY NIGHT. LIKELY WILL BE COLD
ENOUGH IN THE LOWEST LAYERS TO SUPPORT MAINLY SNOW...EXCEPT FOR
MAYBE AT THE IMMEDIATE COAST. FOR NOW THOUGH ANY PRECIPITATION IS
EXPECTED TO BE LIGHT...AS THE AREA SHOULD BE IN THE NORTHERN
PERIPHERY OF THE SYSTEM.
WEDNESDAY SHOULD BE DRY WITH NORTHERN STREAM RIDGING PASSING OVER
THE AREA.
FOR TEMPERATURES SUNDAY-WEDNESDAY A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED. AFTER ABOVE NORMAL
TEMPERATURES ON SUNDAY...BELOW NORMAL TEMPERATURES ARE FORECAST
MONDAY-WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE BUILDS IN TODAY WITH VFR AND A STRONG SURFACE WESTERLY
FLOW GUSTING UP TO 35 KT AT NYC METRO UNTIL ABOUT 21Z. BKN-45-050
CIGS SHOULD SCATTER BY ABOUT 21Z AS WELL. WINDS AND GUSTS SHOULD
THEN GRADUALLY DIMINISH AFTER SUNSET.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KEWR FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KTEB FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KHPN FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KISP FCSTER COMMENTS: MAY SEE AN OCCASIONAL WIND GUST HIGHER
THAN FCST THIS AFTERNOON.
.OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY...
.FRI-SAT...VFR.
.SUNDAY...MVFR WITH CHANCE OF LIGHT RAIN.
.MON...VFR.
.TUE...LOW CONFIDENCE VFR.
&&
.MARINE...
GALE WARNING...WINDS NOW GUSTING TO GALE FORCE ON LAND IN THE NYC
AREA AND THIS WILL MOVE OUT OVER ALL WATERS BY NOON.
THIS EVENING...WINDS LOWER TO SCA LEVEL QUICKLY THIS EVENING...TAPERING
OFF TO BELOW SCA LEVELS AFTER MIDNIGHT TONIGHT.
SUB-SCA CONDITIONS ARE ANTICIPATED ON FRIDAY INTO NEXT WEEK.
&&
.HYDROLOGY...
DRY THROUGH SATURDAY NIGHT WITH NO SIGNIFICANT PRECIPITATION EXPECTED
FROM SUNDAY-WEDNESDAY AT THIS TIME.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ330-335-338-
340-345-350-353-355.
&&
$$
SYNOPSIS...MALOIT
NEAR TERM...TONGUE
SHORT TERM...MALOIT
LONG TERM...MALOIT
AVIATION...GOODMAN
MARINE...BC/TONGUE
HYDROLOGY...MALOIT
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1145 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 704 AM CST THU DEC 25 2014
LITTLE CHANGE WAS MADE TO THE FORECAST AT THIS POINT. SOME
ADJUSTMENT TO CLOUD COVER DUE TO STRATUS TAILING BACK ACROSS THE
NORTHEAST.
&&
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/18Z
ISSUED AT 1145 AM CST THU DEC 25 2014
VFR CONDITIONS INITIALLY WITH SOUTHERLY FLOW...WITH CLOUD
BASES LOWERING THROUGH THE PERIOD. HAVE BROUGHT A FEW NORTHERN
TAF SITES DOWN INTO THE MVFR RANGE...AND GUIDANCE/MODELS SUGGEST
POTENTIAL FOR FURTHER LOWERING TOWARD THE END OF THE PERIOD.
ALSO HINTS THAT SOME FZDZ IS POSSIBLE ACROSS THE FAR NORTH VERY
LATE IN THE PERIOD...SO WILL CONTINUE TO MONITOR AND MAY HAVE TO
INTRODUCE IF CERTAINTY INCREASES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...FAB
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1246 PM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 1246 PM EST THU DEC 25 2014
WILL BE UPDATING THE FORECAST PACKAGE TO HANG ONTO CLOUDS JUST A BIT
LONGER AS PESKY LOW SC DECK GRADUALLY DISSIPATES THROUGH THE LATE
AFTERNOON AND EARLY EVENING TIME FRAME. OTHERWISE JUST MINOR TWEAKS
TO THE HOURLY GRIDS TO ACCOUNT FOR LATEST OBSERVATIONS.
UPDATE ISSUED AT 938 AM EST THU DEC 25 2014
UPDATED GRIDS FOR LATEST HOURLY OBS AND TRENDS. THIS RESULTED IN VERY
MINOR CHANGES TO THE FORECAST. OVERALL FORECAST IS IN EXCELLENT SHAPE
THIS CHRISTMAS MORNING. STILL PICKING UP ON SOME PATCHY DRIZZLE IN
THE OBS AND ON RADAR. CLOUD TOP TEMPS SUGGEST THERE IS SOME FLURRY
ACTIVITY OUT THERE AS WELL...MAINLY IN THE HIGHER ELEVATIONS. NO
UPDATE TO THE ZONES PLANNED AT THIS TIME.
UPDATE ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIR MASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWN SLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1246 PM EST THU DEC 25 2014
WIND FLOW AT THE SFC AND ALOFT CONTINUES TO BACK TO THE SOUTHWEST.
LOW MVFR STRATOCU DECK WILL ONLY GRADUALLY DISSIPATE THROUGH THE
FIRST 6 HOURS OR SO OF THE FORECAST. OTHERWISE WE FINALLY CLEAR OUT
WITH LIGHT WINDS...GENERALLY FROM THE SOUTH...SOUTHWEST THROUGH THE
REMAINDER OF THE FORECAST PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM...KAS
AVIATION...RAY
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1108 AM MST THU DEC 25 2014
.UPDATE...
SNOW CONTINUES TO WIND DOWN FROM NORTH TO SOUTH. ENDED ADVISORIES
FOR YELLOWSTONE AND NORTHERN BIG HORN COUNTIES. TWH
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL CONTINUE TO IMPACT SHERIDAN INTO THE AFTERNOON...WITH
SNOW COMING TO AN END AROUND BILLINGS AND LIVINGSTON BY LATE
MORNING. CEILINGS WILL REMAIN IFR TO MVFR UNTIL THE SNOW
ENDS...WITH CONDITIONS GENERALLY IMPROVING TO MVFR AFTER THE SNOW
MOVES OUT. MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH MUCH OF
THE DAY AND INTO THE EVENING. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
5/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
9/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
5/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
2/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
6/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
2/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 34-36-37-39>41-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
921 AM MST THU DEC 25 2014
.UPDATE...
KBLX RADAR SHOWING SNOW WINDING DOWN OVER NORTHERN ZONES AS
COLDER AND DRIER AIR GRADUALLY WORKS IN. TAPERED SNOW OFF OVER THE
NORTH TO A FEW SNOW SHOWERS THE REST OF THE MORNING. SNOW WILL
CONTINUE FROM LIVINGSTON TO BILLINGS TO EKALAKA AND AREAS SOUTH
THROUGH THE MORNING. THE SNOW WILL TAPER OFF FROM NORTH TO SOUTH
INTO EARLY AFTERNOON WITH THE SNOW DECREASING TO A FEW SNOW
SHOWERS IN BILLINGS BY NOON. DROPPED THE ADVISORY FOR TREASURE
COUNTY AS ACCUMULATING SNOW HAS EFFECTIVELY STOPPED THERE. A
REPORT OF 10 INCHES WAS RECEIVED AT RED LODGE AS LOCATIONS SOUTH
OF BILLINGS WILL CONTINUE TO SEE ACCUMULATING SNOW INTO EARLY
AFTERNOON. WILL LEAVE THE REST OF THE HIGHLIGHTS IN PLACE.
TEMPERATURES WILL NOT MOVE MUCH TODAY WITH COLD AIR ADVECTION. TWH
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL CONTINUE TO IMPACT SHERIDAN INTO THE AFTERNOON...WITH
SNOW COMING TO AN END AROUND BILLINGS AND LIVINGSTON BY LATE
MORNING. CEILINGS WILL REMAIN IFR TO MVFR UNTIL THE SNOW
ENDS...WITH CONDITIONS GENERALLY IMPROVING TO MVFR AFTER THE SNOW
MOVES OUT. MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH MUCH OF
THE DAY AND INTO THE EVENING. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
+/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
+/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
+/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
4/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
+/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
3/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 34>37-39>41-57-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1149 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU DEC 25 2014
COMPLICATED AVIATION FORECAST AS THE MODELS DEVELOP TWO SEPARATE
BANDS OF SNOW DURING THE 18Z AVIATION FORECAST PERIOD...EACH OF
WHICH WILL BRING SNOW...LOWERED CEILINGS AND REDUCED VISIBILITIES
TO PORTIONS OF THE FORECAST AREA. RIGHT NOW...SNOW AND FZFG IS
SPREADING EAST ACROSS NORTHWESTERN NEBRASKA. KVTN HAS LOWERED BELOW
1SM AS FZFG IMPACTS THE SITE...THE PERIOD OF FOG SHOULD BE BRIEF
HOWEVER...AS SNOW WILL BECOME THE PRIMARY IMPACT LATE THIS
AFTERNOON. SNOW WILL CONTINUE ACROSS NORTHERN NEBRASKA AND THE
WESTERN SANDHILLS INTO THE OVERNIGHT. FRIDAY...THE SECOND BAND
WILL DEVELOP ACROSS SOUTHWEST NEBRASKA DURING THE 12-15Z
TIME FRAME...AND THEN SPREAD NORTHEAST ACROSS KLBF AND KBBW BY
EARLY AFTERNOON /RIGHT AT OR JUST BEFORE 18Z/. SNOW...REDUCED
VISIBILITY AND LOWERED CEILINGS ARE ANTICIPATED ONCE AGAIN. A
PERIOD OF FZDZ MAY BE A CONCERN AS WELL...BUT CONFIDENCE WAS NOT
SUFFICIENT ENOUGH FOR A MENTION IN THE FORECAST. ALL IN ALL FORECAST
UPDATES ARE ANTICIPATED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ FRIDAY FOR
NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1154 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 1152 AM CST THU DEC 25 2014
LATEST RADAR MOSAIC SHOWS SHALLOW WEAK RETURNS MOVING ACROSS
PARTS OF NORTH DAKOTA. THE HRRR SHOWS THE POTENTIAL FOR FLURRIES
THROUGH THE AFTERNOON...AND THAT IS COVERED IN THE GOING FORECAST.
HAVE A SMALL CONCERN THERE COULD BE LIGHT FREEZING DRIZZLE IN SOME
LOCATIONS..BUT FORECAST SOUNDINGS SHOW TEMPERATURES COLD ENOUGH TO
INTRODUCE ICE INTO THE LOW LEVEL CLOUD LAYER...SO CONTINUE WITH
FLURRIES AT THIS POINT. TEMPERATURES HAVE MAXED OUT IN MOST AREAS
WITH A SLOW DECLINE EXPECTED FOR THE AFTERNOON DUE TO LOW LEVEL
COLD AIR ADVECTION.
UPDATE ISSUED AT 950 AM CST THU DEC 25 2014
LIGHT SNOW CONTINUES TO MOVE SLOWLY SOUTH AND EAST AWAY FROM NORTH
DAKOTA THIS MORNING AS PER REGIONAL RADAR MOSAIC. THE LATEST SHORT
TERM MODELS CONFIRM THE TREND WILL CONTINUE...SO AFTER
COLLABORATION WITH SURROUNDING OFFICES HAVE OPTED TO GO WITH FLURRIES
IN THE FORECAST FOR THE REMAINDER OF TODAY. THE REST OF THE
FORECAST IS IN GOOD SHAPE...ONLY CHANGE WAS TO BLEND IN CURRENT
CONDITIONS.
UPDATE ISSUED AT 634 AM CST THU DEC 25 2014
FORECAST IS ON TRACK. ONLY CHANGES WERE TO BLEND TO LATEST OBS.
LATEST HOURLY OBS SHOWED TEMPS RUNNING A LITTLE HIGHER THAN
FORECAST ACROSS THE NORTH UNDER LOWER CEILINGS. ONLY SEEING A
COUPLE REPORTS OF PRECIPITATION...INCLUDING STANLEY WITH ITS
LATEST OBSERVATION. BOWMAN RADAR CONTINUES TO SHOW RETURNS ACROSS
THE SOUTHWEST WHERE HIGH POPS/LOW QPF ARE ALREADY IN PLACE IN THE
FORECAST WITH A DIMINISHING TREND EARLY THIS MORNING. ANY SNOW
ACCUMULATION IN THAT AREA WILL BE MINIMAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST THU DEC 25 2014
THE MAIN CONCERN FOR THE SHORT TERM IS LIGHT SNOW CHANCES ACROSS THE
SOUTHERN TIER OF COUNTIES TODAY.
CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED AT THE BORDER OF
MANITOBA/ONTARIO/MINNESOTA WITH A COLD FRONT EXTENDING WESTWARD
ACROSS NORTH DAKOTA FROM NEAR GRAND FORKS TO BISMARCK TO HETTINGER.
A LARGE LOW LEVEL STRATUS DECK OF CLOUDS WAS BEHIND THE FRONT AND
WAS MOVING SOUTH ACROSS NORTHERN NORTH DAKOTA. THE LOW STRATUS
CLOUDS ARE EXPECTED TO MOVE SOUTH AND REMAIN OVER THE STATE FOR THE
DAYLIGHT HOURS.
ATTENTION TURNS TO SOUTHERN NORTH DAKOTA AND THE SCATTERED AREA OF
LIGHT PRECIPITATION MOVING EAST ALONG THE SOUTH DAKOTA BORDER. THIS
PRECIPITATION IS ASSOCIATED WITH SOME WEAK UPPER LEVEL ENERGY
IMPULSES MOVING EAST IN THE ZONAL FLOW ALOFT. THE ONLY SITE THAT
REPORTED LIGHT SNOW WAS LATE WEDNESDAY EVENING AT OAKES. FARTHER
WEST A LARGER STORM SYSTEM CONTINUES TO DEVELOP...AS THE MAIN UPPER
LEVEL TROUGH OVER THE ROCKIES AT THIS TIME EMERGES INTO THE WESTERN
PLAINS LATER THIS MORNING. THE MODELS CONTINUE TO DEVELOP THIS
SYSTEM FARTHER SOUTH...AND ONLY THE FAR SOUTHWESTERN CORNER OF NORTH
DAKOTA IS FORECAST TO RECEIVE MEASURABLE LIGHT SNOW - NOW LOOKING
LIKE LESS THAN AN INCH OF SNOW IN THE BOWMAN AREA. THUS HAVE LOWERED
PRECIPITATION CHANCES TODAY...THOUGH KEPT CHANCES ALONG THE SOUTH
DAKOTA BORDER THIS MORNING...THEN REDUCED CHANCES TO SLIGHT CHANCE
THIS AFTERNOON.
THUS A CLOUDY CHRISTMAS DAY WITH CHANCES OF LIGHT SNOW IN THE FAR
SOUTHERN TIER OF COUNTIES...AND A CHANCE OF FLURRIES ELSEWHERE.
HIGHS FROM THE LOWER 20S NORTH AND MID TO UPPER 20S SOUTH.
CLEARING FROM NORTHWEST TO SOUTHEAST TONIGHT. LOWS FROM JUST BELOW
ZERO IN THE FAR NORTH CENTRAL TO THE TEENS SOUTH OF JAMESTOWN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 323 AM CST THU DEC 25 2014
THE EXTENDED PERIOD WILL BE CATEGORIZED BY MOSTLY DRY AND MUCH
COLDER WEATHER. 00Z MODELS AND GEFS IN DECENT AGREEMENT WITH UPPER
LEVEL PATTERN...INITIALLY SHOWING CUTOFF LOW APPROACHING HUDSON
BAY AND BROAD TROUGH OVER NORTH AMERICA. EMBEDDED SHORTWAVE IN
NORTHWEST FLOW ON BACKSIDE OF CUTOFF LOW WILL SUPPORT CHANCE OF
SNOW ACROSS THE NORTH ON SATURDAY AND REINFORCING SHOT OF ARCTIC
AIR. WILL ALSO MAINTAIN LOW POPS FOR MAINLY SOUTHWEST ND ON SUNDAY
AS FRONT PROGRESSES SOUTHWARD. MEANWHILE STRONG SURFACE HIGH
BUILDS SOUTHWARD FROM CANADA WITH 1056MB HIGH CENTERED FROM
MONTANA TO WESTERN ND BY 06Z TUE. SURFACE HIGH TO OUR WEST WILL
SUPPORT NORTHERLY SURFACE WINDS FROM LATE WEEKEND INTO TUESDAY
HELPING WIND CHILLS REACH VERY LOW LEVELS. THE CURRENT FORECAST
SHOWS WIND CHILLS LOWER THAN 25 BELOW ZERO SUNDAY NIGHT MAINLY
NORTH AND EAST OF THE MISSOURI RIVER. MONDAY NIGHT AND TUESDAY
NIGHT SHOULD SEE MAJORITY OF CWA HAVING WIND CHILLS IN 25 BELOW
ZERO TO 30 BELOW RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1152 AM CST THU DEC 25 2014
MVFR CEILINGS WILL PREVAIL AT THE AERODROMES...WITH SOME POTENTIAL
FOR BRIEF IFR. PASSING FLURRIES ARE EXPECTED...THOUGH VISIBILITY
RESTRICTIONS ASSOCIATED WITH THEM SHOULD BE MINOR. CEILINGS ARE
EXPECTED TO IMPROVE TO VFR FROM NORTHWEST TO SOUTHEAST STARTING
LATER TONIGHT...WITH THE TREND CONTINUING INTO FRIDAY MORNING.
WINDS SHOULD GENERALLY BE FROM A NORTHWEST DIRECTION...AND WILL
DECREASE IN SPEED TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JV
LONG TERM...JNS
AVIATION...CK
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1144 AM CST THU DEC 25 2014
.AVIATION...
ONLY AVIATION CONCERN FOR THE FIRST 9 HOURS WILL BE GUSTY WINDS AT
ALL TERMINALS. WIND GUST UP TO 30 KTS WILL BE POSSIBLE WITH BEST
POTENTIAL AT KAUS AND NORTH. WIND DIRECTION WILL BE OUT OF THE
SOUTH GENERALLY AND DIE DOWN TO BELOW 12 KTS BY 00Z TONIGHT.
OVERNIGHT...WINDS WILL SHIFT TO THE SOUTHEAST AND MOISTURE WILL
INCREASE RESULTING IN MVFR/IFR CIG DEVELOPMENT BY EARLY MORNING.
ALSO...MODELS ARE SUGGESTING BELOW 1 SM FOG ALONG THE I35 CORRIDOR
TERMINALS BUT CONFIDENCE IN THE DENSITY OF THE FOG IS LOW DUE TO
THE VERY DRY ATMOSPHERE TODAY. WENT AHEAD AND INCLUDED FOG BUT
KEPT IT AT LOW MVFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 942 AM CST THU DEC 25 2014/
UPDATE...
FORECAST PACKAGE LOOKS ON TRACK FOR TEMPS AND DEWPOINTS. WENT
AHEAD AND UPDATED WIND AND WIND GUST GRIDS WITH LATEST RAP MODEL
AS IT WAS CAPTURING THE GUSTY WINDS ALREADY OBSERVED ON THE
ESCARPMENT AND NORTHERN HILL COUNTRY.
ALSO RE-RAN THE FIRE WX GRIDS USING LATEST MODEL DATA TO ADD SOME
PRECISION TO THE MIN RH VALUES. APPEARS THAT RH VALUES SHOULD STAY
ABOVE 20 PERCENT. WILL CONTINUE TO MONITOR CLOSELY.
TB3
PREV DISCUSSION... /ISSUED 549 AM CST THU DEC 25 2014/
AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THIS
EVENING. SURFACE SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING
CONTINUING THROUGH THE AFTERNOON AS MIXING TAKES PLACE AND A
SURFACE TROUGH PUSHES ACROSS NORTHWEST TEXAS. EXPECT GUSTS UP TO
25 KNOTS. LOW LEVEL MOISTURE WILL INCREASE TONIGHT AS SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST. WE ARE ANTICIPATING MVFR
CONDITIONS FOR ALL AREA TERMINALS OVERNIGHT AROUND 09Z AND 11Z
ACROSS KDRT. VFR CONDITIONS SHOULD RETURN BY 18Z FRIDAY.
PREV DISCUSSION... /ISSUED 336 AM CST THU DEC 25 2014/
SHORT TERM (TODAY THROUGH FRIDAY)...
UPPER AIR ANALYSIS LAST EVENING SHOWED A DEEP TROUGH EXTENDING
FROM THE GREAT LAKES TO EAST TEXAS WITH A RIDGE BUILDING UP
THROUGH THE ROCKIES. THERE WAS ANOTHER TROUGH EXTENDING FROM
WASHINGTON TO NORTHERN CALIFORNIA. WATER VAPOR SATELLITE IMAGERY
SHOWED MID-LEVEL DRY AIR OVER SOUTH CENTRAL TEXAS WITH MOISTURE
SPREADING INTO WEST TEXAS. AT THE SURFACE HIGH PRESSURE WAS
CENTERED ALONG THE COAST NEAR SOUTH PADRE ISLAND. THE PRESSURE
GRADIENT WAS NOT WELL DEFINED...BUT WINDS WERE TURNING TO THE WEST
AND SOUTHWEST. THE WEST COAST UPPER TROUGH WILL DIG DOWN INTO THE
SOUTHWEST AND THE UPPER FLOW OVER TEXAS WILL BECOME SOUTHWESTERLY.
BENEATH THIS TROUGH A FRONTAL SYSTEM WILL MOVE INTO WEST TEXAS
REACHING JUST NORTHWEST OF VAL VERDE COUNTY BY THE END OF THE
PERIOD. THE SURFACE HIGH WILL MOVE OUT INTO THE GULF AND LOW LEVEL
WINDS WILL BE SOUTHEASTERLY BRINGING WARM...MOIST AIR TO THE
REGION. THERE MAY BE SUFFICIENT ISENTROPIC LIFT FRIDAY TO PRODUCE
LIGHT RAIN OVER THE EASTERN COUNTIES. OTHERWISE THIS PERIOD WILL
BE WARM AND DRY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
MODELS SHOW THE UPPER TROUGH CONTINUING TO DIG SOUTH INTO MEXICO
INITIALLY...BUT THEN THERE ARE DIFFERENCES ON WHEN IT KICKS OUT TO
THE EAST. THEY ALL AGREE ON FRONTAL PASSAGE THROUGH OUR CWA FRIDAY
NIGHT AND SATURDAY MORNING. BEST MOISTURE WILL BE OVER THE EASTERN
HALF OF THE AREA...SO THAT IS WHERE THE BEST CHANCES FOR RAIN WILL
BE. MODELS DIFFER ON THE MOVEMENT OF THE UPPER TROUGH ACROSS TEXAS
SUNDAY. THE ECMWF IS FASTEST AND THE CANADIAN IS SLOWEST. WILL
LEAN TOWARD THE GFS WHICH IS IN THE MIDDLE. THIS WILL MEAN
CONTINUED CHANCES FOR RAIN SUNDAY. AFTER THIS TROUGH PASSES THE
UPPER PATTERN WILL BECOME ZONAL FOR THE FIRST PART OF NEXT WEEK
RETURNING DRY WEATHER FOR MONDAY. TUESDAY ANOTHER COLD FRONT WILL
MOVE INTO THE REGION. THIS WILL BRING ANOTHER SLIGHT CHANCE FOR
PRECIPITATION AND COLDER AIR. DEPENDING ON TIMING THERE IS A
CHANCE FOR SOME WINTER TYPE PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY MORNING OVER THE NORTHEASTERN PART OF THE FORECAST AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 63 52 68 55 59 / 0 - 10 20 40
AUSTIN BERGSTROM INTL AIRPORT 63 49 69 56 60 / 0 - 10 20 40
NEW BRAUNFELS MUNI AIRPORT 64 50 70 57 62 / 0 - 10 20 40
BURNET MUNI AIRPORT 60 49 65 49 52 / 0 - 10 20 40
DEL RIO INTL AIRPORT 63 44 65 46 60 / 0 0 - 10 10
GEORGETOWN MUNI AIRPORT 61 51 66 52 54 / 0 - 10 20 40
HONDO MUNI AIRPORT 64 45 68 52 60 / 0 - 10 20 30
SAN MARCOS MUNI AIRPORT 64 50 69 57 61 / 0 - 10 20 40
LA GRANGE - FAYETTE REGIONAL 64 53 71 59 64 / 0 - 20 30 40
SAN ANTONIO INTL AIRPORT 63 51 69 56 61 / 0 - 10 20 40
STINSON MUNI AIRPORT 64 50 70 56 62 / 0 - 10 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
254 PM CST THU DEC 25 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 254 PM CST THU DEC 25 2014
MAIN FORECAST CONCERNS ARE ON LIGHT FREEZING DRIZZLE POTENTIAL
TONIGHT. FOCUS THEN TURNS TO SNOW ACCUMULATIONS FRIDAY NIGHT
THROUGH SATURDAY MORNING.
LIGHT FREEZING DRIZZLE OR SNOW IS POSSIBLE TONIGHT OVER PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. A MID LEVEL
TROUGH WILL PUSH EAST OUT OF THE DAKOTAS TONIGHT INTO FRIDAY
PRODUCING A BAND OF LIGHT SNOW AND POSSIBLY LIGHT FREEZING
DRIZZLE...MAINLY NORTHWEST OF THE FORECAST AREA. CONFIDENCE IS LOW
ON THE FREEZING DRIZZLE OCCURRING TONIGHT SO DECIDED TO KEEP IT
AS PROBABILITY INSTEAD OF COVERAGE. IF THE DRIZZLE DEVELOPS...SOME
VERY LIGHT ICING IS POSSIBLE ON UNTREATED ROADS AND ELEVATED
SURFACES. ALSO...MESOSCALE MODELS ARE SUGGESTING THE POTENTIAL FOR
SOME FOG TONIGHT RIGHT ALONG THE SURFACE TROUGH LATE TONIGHT INTO
FRIDAY MORNING. WILL HAVE TO KEEP AN EYE ON THIS DURING THE
EVENING AND OVERNIGHT HOURS. OTHERWISE PLAN ON LOWS FALLING INTO
THE UPPER 20S TO LOWER 30S TONIGHT.
ANOTHER TROUGH MOVES EAST OUT OF THE NORTHERN PLAINS FRIDAY AS A
SEPARATE TROUGH LIFTS NORTHEAST OUT OF THE SOUTHWEST CONUS. SNOW AND
RAIN LOOKS TO DEVELOP LATE FRIDAY AFTERNOON...INCREASING IN
COVERAGE GOING INTO FRIDAY NIGHT. OTHERWISE...PLAN ON MOSTLY
CLOUDY SKIES WITH AREAS OF DRIZZLE AND POSSIBLY SOME FOG ON FRIDAY
WITH HIGH TEMPERATURES RANGING FROM THE LOWER 30S OVER SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN TO AROUND 40 ACROSS FAR
SOUTHWEST WISCONSIN.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 254 PM CST THU DEC 25 2014
BY FRIDAY EVENING...A BAND OF SNOW SHOULD BE IN PLACE FROM PORTIONS
OF NORTHEAST IOWA...SOUTHEAST MINNESOTA...INTO NORTH CENTRAL
WISCONSIN. A MIX OF RAIN OR SNOW IS EXPECTED ACROSS FAR NORTHEAST
IOWA INTO SOUTHWEST WISCONSIN. THERE IS UNCERTAINTY ON WHETHER OR
NOT THE SOUTHERN STREAM AND NORTHERN STREAM TROUGHS WILL INTERACT
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. THE NAM AND GFS OFFER
MORE PROGRESSIVE SOLUTIONS WHICH WOULD YIELD LIGHTER SNOWFALL
AMOUNTS. THE GEM AND ECMWF SOLUTIONS ARE MUCH STRONGER...AND
DEEPEN THE TROUGH OVER THE FORECAST AREA. IF THESE STRONGER
SOLUTIONS VERIFY...WE WOULD SEE SNOW ACCUMULATIONS IN THE 2 TO 4
INCH RANGE WITH HIGHER AMOUNTS POSSIBLE. EITHER WAY...TRAVEL WILL
BE IMPACTED BY THIS SYSTEM WITH SLIPPERY ROADS EXPECTED FRIDAY
NIGHT INTO SATURDAY MORNING. CONFIDENCE IS HIGH ON SEEING
ACCUMULATIONS IN THE 1 TO 2 INCH RANGE. LOW CONFIDENCE ON SEEING
AMOUNTS IN THE 2 TO 4 INCH PLUS RANGE AT THIS TIME.
THE STORM SYSTEM WILL EXIT THE REGION LATE SATURDAY AFTERNOON INTO
SATURDAY NIGHT WITH SEASONABLE TEMPERATURES EXPECTED THROUGH SUNDAY.
A MUCH COLDER AIRMASS THEN SWEEPS INTO THE REGION MONDAY AFTERNOON
INTO MONDAY NIGHT WITH TEMPERATURES PLUMMETING INTO THE SINGLE
DIGITS BELOW ZERO ACROSS MUCH OF THE REGION. SOME LIGHT SNOW IS
POSSIBLE MONDAY AFTERNOON MAINLY SOUTH OF INTERSTATE 90 AS A WEAK
SHORTWAVE MOVES THROUGH. OTHERWISE...THE MAIN FOCUS IS ON THE COLD
TEMPERATURES MOVING IN. HIGHS WILL ONLY BE IN THE SINGLE DIGITS
TO LOWER TEENS TUESDAY..WITH LOWS FALLING INTO THE SINGLE DIGITS
BELOW ZERO TUESDAY NIGHT. WIND CHILLS MAY ALSO BE A CONCERN MONDAY
NIGHT AND TUESDAY NIGHT OVER THE OPEN AREAS OF NORTHEAST IOWA...
SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN WHERE WIND CHILL
VALUES COULD FALL TO AROUND -20.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1132 AM CST THU DEC 25 2014
THE SOUTH TO SOUTHWESTERLY FLOW ABOVE THE GROUND HAS BEEN STRONG
ENOUGH TO HELP BRING IN SOME DRIER AIR FROM IOWA AND SCATTER OUT
THE CLOUDS AT RST. RAP MODEL RUNS HAVE BEEN A BIT TOO
PESSIMISTIC...SO HAVE REVERTED AND MADE THE TAFS MORE OPTIMISTIC.
HAVE NOW BROUGHT SCATTERING TO VFR CONDITIONS AT LSE AT 21Z. A
CONDITIONS SHOULD REMAIN VFR THROUGH A GOOD DEAL OF TONIGHT. LATE
IN THE NIGHT...A TROUGH OVER SOUTHWEST MN LOOKS ON TRACK TO CROSS
RST...AND TOWARDS SUNRISE AT LSE. LOW CEILING STRATUS RETURNS IN
THE WAKE OF THE TROUGH...WITH RST LIKELY DROPPING TO IFR AND
LIFR. MEANWHILE...THE VALLEY SHOULD HELP PREVENT LSE FROM DROPPING
BELOW MVFR. ADDITIONALLY...SOME LOWER VISIBILITIES APPEAR LIKELY
TO ACCOMPANY THE LOW STRATUS...PARTICULARLY OVER THE HIGHER
TERRAIN SITE OF RST. SOME GUIDANCE WANTS TO BRING THEM DOWN TO
LIFR. CONFIDENCE ONLY HIGH ENOUGH TO BRING IT DOWN TO IFR. THERE
COULD ALSO BE SOME PATCHY FREEZING DRIZZLE WITH THESE LOW
VISIBILITIES. COVERAGE AT THIS TIME NOT WIDESPREAD ENOUGH TO
INCLUDE IN THE TAF.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST THU DEC 25 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CLOUD COVER/TEMPERATURES
FOLLOWED BY THE CHANCES FOR DRIZZLE/FREEZING DRIZZLE TONIGHT.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE IS ALIGNED ALONG THE
MISSISSIPPI RIVER AND DRIFTING EASTWARD AS A BROAD AREA OF LOW
PRESSURE DEVELOPS IN THE PLAINS. FURTHER ALOFT...THE MID LEVEL
FLOW IS FLATTENING OUT ACROSS THE NORTHERN PLAINS/UPPER
MISSISSIPPI RIVER VALLEY AS A TROUGH DIGS ACROSS THE ROCKIES. A
LOW LEVEL STRATUS DECK IS PRODUCING SOME SCATTERED FLURRIES DUE TO
THE TOP OF THE SATURATED LAYER/CLOUD DECK BEING AROUND -10C
ACCORDING TO IR SATELLITE. THIS IS COLDER THAN WHAT LOCAL SHORT
TERM SOUNDINGS SUGGEST IS OCCURRING. IR SATELLITE/OBS ACTUALLY
SHOW THE WESTERN EDGE OF IT RAPIDLY CLEARING IN ACROSS CENTRAL
IOWA/SOUTHWEST MINNESOTA AND IS TIMED TO BE MOVING THROUGH THE
REGION THIS MORNING INTO EARLY AFTERNOON WITH EROSION OCCURRING
FROM SOUTHWEST TO NORTHEAST. HOWEVER...HIGH LEVEL CLOUD COVER IS
QUICK ON ITS HEELS AND WILL LIMIT THE POTENTIAL OF SEEING ANY
SUNLIGHT UNLESS IT ENDS UP THINNING OUT AS IT APPROACHES. BASED
ON THE LOW CLOUDS CLEARING OUT...BUMPED UP FORECAST HIGH
TEMPERATURES A FEW DEGREES AS SURFACE WINDS COME AROUND TO THE
SOUTHWEST AND BRING SOME WARMER AIR INTO THE REGION.
GOING INTO TONIGHT THE QUESTION IS WITH WHETHER ANY
DRIZZLE/FREEZING DRIZZLE WILL OCCUR AS LOW LEVEL MOISTURE
TRANSPORT RAMPS UP INTO THE REGION. THE 25.00Z MODELS ARE ALL IN
AGREEMENT THAT A 30-40KT LOW LEVEL JET WILL DEVELOP ACROSS THE
SOUTHERN PLAINS THIS EVENING WITH IT NOSING NORTHEASTWARD AS THE
NIGHT PROGRESSES. FORECAST SOUNDINGS FROM THE NAM/GFS BOTH SHOW A
DEEPENING SATURATED LOW LEVEL LAYER WHICH IS NOT COLD ENOUGH TO
FORM ICE. THERE APPEARS TO BE SOME WEAK LIFT THANKS TO THE LLJ
NOSE/SURFACE BOUNDARY PROVIDING SOME CONVERGENCE. THE 25.00/06Z
NAM SURFACE REFLECTIVITY PANES SHOW THIS DRIZZLE DEVELOPING FROM
THE WEST OVERNIGHT...PARTICULARLY AFTER MIDNIGHT AND ALONG WHERE
THE CONVERGENCE IS IN THE SURFACE/LOW LEVELS. WITH THE SOUTHERLY
WINDS KEEPING THE WARMER AIR IN PLACE...THERE IS SOME QUESTION
ABOUT HOW COLD TEMPERATURES WILL BE AND WHETHER THE DRIZZLE WILL
BE FREEZING OR NOT. WILL HAVE TO MONITOR TRENDS...BUT WITH
TEMPERATURES AT OR JUST ABOVE FREEZING...EXPECT THAT THE IMPACT
WILL NOT BE THAT GREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU DEC 25 2014
GOING INTO THIS WEEKEND ON INTO THE MIDDLE OF NEXT WEEK...THE
FOCUS IS ON THE POTENTIAL FOR AN ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY FOLLOWED BY THE DRASTICALLY COLDER AIR MASS THAT
WILL SETTLE IN BY MIDWEEK.
EYES WILL BE ON THE MID LEVEL TROUGH DIGGING ACROSS THE
SOUTHWESTERN US AND HOW IT WILL EJECT INTO THE UPPER MIDWEST.
PREVIOUS MODEL RUNS HAD THIS WAVE COMING THROUGH AS MAINLY AN OPEN
TROUGH/SURFACE LOW BUT THE 25.00Z TRENDS WITH THE NAM/GFS/ECMWF
ARE TO GO DEEPER. THE ECMWF IS THE DEEPEST/SLOWEST WITH THIS
FEATURE AND BRINGS THE HEAVIEST SNOW TOTALS...POSSIBLY ADVISORY
WORTHY...ALONG WITH IT. ALL THREE MODELS ARE SHOWING A BAND OF
HEAVIER SNOW OCCURRING IN THE DEFORMATION AREA OF THE TROUGH WHICH
RUNS FROM SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. MOST
OF THE AREA SHOULD JUST SEE SNOW FROM THIS SYSTEM...BUT SOME
PORTIONS OF EASTERN IOWA AND SOUTHWEST WISCONSIN COULD BE WARM
ENOUGH TO CHANGE IT OVER TO RAIN. THE ECMWF TRENDS WILL HAVE TO BE
MONITORED BECAUSE IT WOULD SET US UP FOR SOME HIGHER SNOWFALL
TOTALS THAN CURRENTLY BEING FORECAST. WITH IT BEING A NEW
DIRECTION BEING TAKEN WITH THIS ONE MODEL...DECIDED IT WOULD BE
BEST TO JUST BLEND THAT SOLUTION WITH THE NAM/GFS IDEA TO COME UP
WITH SNOW ACCUMULATIONS OF 1 TO 3 INCHES. THE MAIN PERIOD TO WATCH
WILL BE SATURDAY MORNING AS THE ECMWF HAS AROUND 0.25 INCHES OF
QPF IN THAT PERIOD WHEN THE NAM/GFS ONLY HAS 0.01 INCHES OR SO.
BEYOND THIS SYSTEM IT LOOKS LIKE WE WILL HAVE AN EXTENDED PERIOD
OF HAVING A COLDER AIR MASS WHERE HIGHS ONLY GET INTO THE
TEENS...PARTICULARLY GOING INTO TUESDAY AND WEDNESDAY. PERHAPS THE
SILVER LINING HERE IS THAT WITH THIS COLD AIR AND A BROAD RIDGE OF
HIGH PRESSURE DROPPING DOWN ACROSS MUCH OF THE CENTRAL US...SKIES
SHOULD BE CLEAR WHICH WOULD BE WELCOME AFTER THIS EXTENDED PERIOD
OF OVERCAST CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1132 AM CST THU DEC 25 2014
THE SOUTH TO SOUTHWESTERLY FLOW ABOVE THE GROUND HAS BEEN STRONG
ENOUGH TO HELP BRING IN SOME DRIER AIR FROM IOWA AND SCATTER OUT
THE CLOUDS AT RST. RAP MODEL RUNS HAVE BEEN A BIT TOO
PESSIMISTIC...SO HAVE REVERTED AND MADE THE TAFS MORE OPTIMISTIC.
HAVE NOW BROUGHT SCATTERING TO VFR CONDITIONS AT LSE AT 21Z. A
CONDITIONS SHOULD REMAIN VFR THROUGH A GOOD DEAL OF TONIGHT. LATE
IN THE NIGHT...A TROUGH OVER SOUTHWEST MN LOOKS ON TRACK TO CROSS
RST...AND TOWARDS SUNRISE AT LSE. LOW CEILING STRATUS RETURNS IN
THE WAKE OF THE TROUGH...WITH RST LIKELY DROPPING TO IFR AND
LIFR. MEANWHILE...THE VALLEY SHOULD HELP PREVENT LSE FROM DROPPING
BELOW MVFR. ADDITIONALLY...SOME LOWER VISIBILITIES APPEAR LIKELY
TO ACCOMPANY THE LOW STRATUS...PARTICULARLY OVER THE HIGHER
TERRAIN SITE OF RST. SOME GUIDANCE WANTS TO BRING THEM DOWN TO
LIFR. CONFIDENCE ONLY HIGH ENOUGH TO BRING IT DOWN TO IFR. THERE
COULD ALSO BE SOME PATCHY FREEZING DRIZZLE WITH THESE LOW
VISIBILITIES. COVERAGE AT THIS TIME NOT WIDESPREAD ENOUGH TO
INCLUDE IN THE TAF.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ