Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/20/12
AREA FORECAST DISCUSSION
NWS DENVER CO
821 PM MST THU JAN 19 2012
.UPDATE...
&&
.SHORT TERM...HAVE ADDED A SNOW AND BLOWING SNOW ADVISORY FOR MTN
AREAS NORTH OF I-70 THROUGH FRIDAY MORNING. AN UPPER LEVEL JET
WILL SAG SOUTHWARD OVER THE NRN MTNS OVERNIGHT AND COMBINE WITH
DEEPER MOISTURE TO ALLOW FOR SOME ENHANCEMENT OF SNOWFALL ALONG
WITH GUSTY WINDS AT TIMES ALTHOUGH LAPSE RATES ARE NOT THAT GREAT. MAY
STILL SEE A PERIOD OF HIGH WINDS IN THE NORMALLY WINDY AREAS OF
THE FOOTHILLS AFTER MIDNIGHT THRU EARLY FRI MORNING ALTHOUGH THE
SET UP IS NOT AS FAVORABLE AS LAST NIGHT.
.AVIATION...WINDS HAVE BECOME MORE WLY AT THE AIRPORT THIS EVENING. SHORT
RANGE MODELS HAVE BEEN USELESS IN FORECASTING WIND DIRECTIONS THIS
EVENING. WILL KEEP A GENERAL WLY COMPONENT OVERNIGHT ALTHOUGH THE
CURRENT NAM AND RUC SHOW WINDS BECOMING MORE SSW IN THE 10Z-12Z
TIMEFRAME.
&&
.PREV DISCUSSION... /ISSUED 225 PM MST THU JAN 19 2012/
SHORT TERM...MAIN CONCERN THROUGH FRIDAY MORNING IS YET MORE HIGH
WIND POTENTIAL IN THE FOOTHILLS TONIGHT AND EARLY FRIDAY MORNING.
LOOKS LIKE A SIMILAR SET UP LIKE LAST NIGHT FOR THE STRONG WINDS
TO DEVELOP. CROSS SECTIONS SHOW THE STRONG WINDS SLIDING DOWN EAST
SLOPES OF 60-75KT OF CROSS BARRIER FLOW. SHEAR PROFILE LOOKS GOOD
FROM AMPLIFIED WAVE AND STABILITY IMPROVES THROUGH THE NIGHT. WILL
GO AHEAD AND ISSUE A HIGH WIND WARNING FOR THE FOOTHILLS ZONES.
NOT SURE ABOUT THE BASE OF THE FOOTHILLS AS ANY HIGH WIND WOULD
LIKELY BE MORE LOCALIZED LIKE THIS MORNING AND CONFINED TO ONLY A
FEW SPOTS.
AS FOR THE MOUNTAINS QUITE A BIT OF DISCUSSION BETWEEN OFFICES IN
THE SNOW POTENTIAL FOR TONIGHT AND FRIDAY. OVERALL FEELING IS THAT
THE MOISTURE WON`T BE ALL THAT DEEP ALONG WITH MARGINAL LAPSE
RATES AROUND 4C/KM. UPSTREAM OBSERVATIONS ACROSS UTAH AND NEVADA
NOT SHOWING MUCH PRECIP WITH CEILINGS MAINLY ABOVE 6,000 FEET.
MODEL CROSS SECTIONS NOT ALL THAT DEEP WITH THE MOISTURE YET THE
NAM INDICATES ALMOST 10 INCHES OVER ZONE 31. THINK THIS IS
OVERDONE AND WILL GO MORE CONSERVATIVE.
ACROSS LOWER ELEVATIONS...AIRMASS WILL BE DRY AND MILD EXCEPT OVER
THE FAR NORTHEAST PLAINS WITH COOLER AIRMASS STILL IN PLACE.
LONG TERM...SNOW WILL BE DIMINISHING OVER THE HIGHER MOUNTAINS
FRIDAY NIGHT AS AN UPPER RIDGE MOVES OVERHEAD. WILL LIKELY SEE
COOLER TEMPERATURES FRIDAY NIGHT FORECAST AREA WIDE DESPITE THE
RIDGING AS THE SURFACE PRESSURE GRADIENT WEAKENS AND ALLOWS FOR
LIGHT WINDS AND RADIATIONAL COOLING.
THE NEXT PACIFIC TROUGH WILL QUICKLY MOVE WENCHER OVER THE WEST
COAST SATURDAY MORNING QUICKLY MOVING EAST TO AFFECT COLORADO THAT
DAY. SNOW WILL BE INCREASING DUE TO DYNAMICS AND OROGRAPHICS AS
THE MOISTURE DEEPENS IN WESTERLY FLOW AND LAPSE RATES BECOME
FAVORABLE. THIS ALONG WITH MODERATE UPWARD QG VERTICAL VELOCITIES
PASSING OVERHEAD WILL ALLOW FOR SNOW TO REACH DOWN INTO THE HIGH
VALLEYS AS WELL BUT STILL BE FOCUSED ON WESTERLY SLOPES. EXPECTING
A PERIOD OF MODERATE TO HEAVY SNOW FOR THE MOUNTAINS SATURDAY
NIGHT AS THE COLD FRONT ARRIVES TO BRING THE MORE FAVORABLE
NORTHWESTERLY FLOW. AMOUNTS OF 1 TO 2 FEET ALONG WEST SLOPES ARE
VERY POSSIBLE FOR THE NORTHERN AND CENTRAL MOUNTAINS...WILL LIKELY
NEED HIGHLIGHTS AS THIS TIME PERIOD NEARS. WINDS MAY BE A CONCERN
AS WELL WITH THE FRONT WHICH WOULD PRODUCE BLOWING SNOW. AS THE
FRONT MOVES SOUTHEAST ACROSS THE REST OF THE FORECAST AREA LATE
SATURDAY NIGHT INTO SUNDAY...MAY SEE A FEW SHOWERS FORM OVER THE
PLAINS BUT LIGHT PRECIPITATION AMOUNTS ARE EXPECTED. HIGH
TEMPERATURES WILL BE ABOUT 10 TO 15 DEGREES COOLER SUNDAY...AND
MAY NEED TO BE LOWERED STILL.
RIDGING BEHIND THIS STRONGER SYSTEM WILL QUICKLY DIMINISH THE
SNOW OVER THE MOUNTAINS SUNDAY NIGHT. MONDAY WILL BE ANOTHER SHORT
BREAK WITH WARMER TEMPERATURES BEFORE ANOTHER SYSTEM IN THE
PROGRESSIVE PATTERN APPROACHES FOR TUESDAY...THEN MORE OF A ZONAL
FLOW IS EXPECTED OVER THE STATE AS MODELS SHOW A CUTOFF LOW OVER
MEXICO. WILL KEEP POPS IN THE MOUNTAINS THROUGH THIS PERIOD DUE
TO THE RELATIVELY MOIST WESTERLY FLOW AND ALSO DUE TO UNCERTAINTIES
WITH THESE SYSTEMS. FOR THE PLAINS...OTHER THAN LOW POPS FOR THE
SYSTEM MONDAY NIGHT TUESDAY WILL KEEP THE FORECAST DRY. HIGHS WILL
BE NEAR NORMAL DURING AND AFTER THE TROUGH PASSAGE
TUESDAY...OTHERWISE ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
NORTHEAST COLORADO.
AVIATION...LOOKS LIKE WINDS AT APA AND DEN WILL REMAIN FROM THE
EAST AND BJC FROM THE WEST FOR THE REST OF THIS AFTERNOON AS
MESOCYCLONE REMAINS OVER SOUTHERN PORTIONS OF DENVER. BJC WILL
HAVE PUFFS OF WESTERLY WINDS AND MAYBE A BIT STRONGER LATER
TONIGHT BUT NOT ALL THAT CONFIDENT BASED ON THEIR LACK OF WIND
FROM LAST NIGHT. APA AND DEN SHOULD SHIFT A BIT MORE SW-W FOR
TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 10 AM MST FRIDAY FOR COZ035-036.
WINTER WEATHER ADVISORY UNTIL 11 AM MST FRIDAY FOR COZ031-033.
&&
$$
SHORT TERM...RPK
LONG TERM....KRIEDERMAN
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS ALBANY NY
1229 AM EST WED JAN 18 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS MOVES ALONG
THE SAINT LAWRENCE RIVER VALLEY TONIGHT. THE COLD FRONT TO THE
SYSTEM WILL SWING ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND
OVERNIGHT...WITH SCATTERED SNOW SHOWERS...BLUSTERY...AND COLD
CONDITIONS FOR WEDNESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN
WEDNESDAY AFTERNOON INTO THURSDAY MORNING...AS A CLIPPER LOW WILL
BRING SOME SCATTERED SHOWERS SHOWERS LATE THURSDAY AFTERNOON THROUGH
THURSDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
VERY STRONG WINDS JUST OUTSIDE THE FORECAST AREA COULD SCRAPE THE
SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY EARY THHIS MORNING
AND INTO MID MORNING. SO...A HIGH WIND WARNING HAS BEEN ISSUED
THERE. THE PRESSURE RISE FALL COUPLET IS TRACKING NORTHEAST ALONG
AND JUST NORTH OF THE U.S. CANADIAN BORDER WHICH IMPLIES THE
STRONGEST WINDS MAY JUST MISS THE SOUTHERN ADIRONDACKS...BUT CLOSE
ENOUGH WHERE IS WOULD BE BEST TO WARN PEOPLE OF THE POSSIBILITY OF
DAMAGING WINDS JUST IN CASE. OF COURSE THE WIND ADVISORY IS STILL
IN EFFECT FOR OTHER AREAS.
JUST SOME MINOR ADJUSTMENTS TO TEMPERATURES BASED ON CURRENT
OBSERVATIONS AND TRENDS.
PREV AFD BELOW...
AS OF 930 PM...FORECAST ON TRACK. UPDATED POPS TO TIME COLD FRONT
AND SHOWERS ACROSS FORECAST AREA. HAVE LIKELY POPS ALONG BOUNDARY.
WINDS WILL SHIFT AND INCREASE BECOMING GUSTY WITH THE FRONTAL
PASSAGE. ADJUSTED TEMPERATURES AND DEW POINTS BASED ON OBSERVATIONAL
DATA.
AS OF 630 PM EST...WE WILL BE ALLOWING THE WINTER WX ADVISORY FOR
THE MIXTURE OF SLEET AND FREEZING RAIN TO EXPIRE AT 7 PM. THE
MESONET OBSERVATIONS SHOW TEMPERATURES HAVE MOSTLY RISEN ABOVE
FREEZING AT THIS TIME...AND THE BATCH OF PRECIPITATION HAS MOVED
WELL EAST OF THE REGION. WE HAVE TRIED TO TIME THE SHOWERS IN
AHEAD OF THE COLD FRONT. A NARROW COLD FRONTAL RAIN BAND HAS
DEVELOPED AHEAD OF THE FRONT OVER WRN NY WITH SOME STRONG TO
SEVERE CONVECTION. HOWEVER...WE BELIEVE THIS SHOULD WEAKEN OVER
THE NEXT FEW HOURS. WE WILL CONTINUE WITH THE WIND ADVISORY OVER
THE FORECAST AREA WITH GUSTS TO 50-55 MPH. WE WILL CONTINUE TO
MONITOR THE UPSTREAM OBSERVATIONS IF ANY UPGRADE TO A HIGH WIND
WARNING IS NECESSARY. OVERALL...HAVE PCPN CHANGING FROM RAIN TO
SNOW SHOWERS SHORTLY BEFORE MIDNIGHT NORTH AND WEST OF THE CAPITAL
REGION....AND SOUTH AND EAST BTWN 06Z-09Z. THE SHOWALTER VALUES
ARE GENERALLY +1 TO +3C AHEAD OF THE FRONT...SO WE WILL NOT BE
INCLUDING THUNDER AT THIS TIME. WE WILL ADD SOME PATCHY FOG OVER
THE MID HUDSON VALLEY...AND NW CT PRIOR TO MIDNIGHT TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM...IT HAS BEEN ANOTHER ACTIVE AND BUSY DAY ACROSS THE
ALY FORECAST AREA. THE NRN TIER HAS HAD MANY LOCATIONS HUNG UP IN
THE UPPER 20S TO NEAR THE FREEZING MARK IN THE THE MID TO LATE
PM...AS THE CURRENT AREA OF PCPN ON THE KENX/NORTHEAST MOSAIC
RADAR HAS PRODUCED PERIODS OF FREEZING RAIN. WE HAD ONE REPORT
COME IN AT 3 PM IN FAIRFIELD OF HERKIMER COUNTY WITH TWO TENTHS OF
AN INCH OF ICE...AND A TEMP OF 31F. THE POTENT LOW PRESSURE SYSTEM
APPROACHING FROM JUST NORTHEAST OF LAKE ERIE THIS HOUR HAS A
DOUBLE WARM FRONT STRUCTURE. THE FIRST WEAK WARM FRONT WENT
THROUGH MOST THE REGION THIS MORNING. A SECOND WARM FRONT OR
THERMAL TROUGH WITH A SHORT-WAVE IN THE SW FLOW HAS FOCUSED THE
AREA OF PCPN. WE WILL BE EXTENDING THE WINTER WEATHER ADVISORY FOR
THE ERN DACKS...LAKE GEORGE-NRN SARATOGA REGION...AND SRN VT
UNTIL 7 PM. WE WILL BE EXPIRING HERKIMER...MONTGOMERY...SRN FULTON
COUNTIES AT 4 PM...AND PHRASE IT AS POCKETS OF FREEZING RAIN...AS
THE LATEST MESONET SITES SHOW TEMPERATURES WARMING ABOVE FREEZING
AT THIS TIME IN THESE SPOTS.
THE OTHER BIG ISSUE TONIGHT IS THE SFC CYCLONE MOVING NORTHEAST
ALONG THE ST LAWRENCE RIVER VALLEY. THE NAM20 INDICATES AN
IMPRESSIVE ISALLOBARIC RISE-FALL PRESSURE COUPLET. WE ARE
EXPECTING 10-12 HPA/3 HRS RISES MOVING NEAR MASSENA WITH THE
DEEPENING AND INTENSIFYING WAVE EARLY THIS EVENING. THE GREATEST PRESSURE
RISES IN OUR AREA ARE 5-6 HPA/3 HRS. WE HAVE EXPANDED THE WIND
ADVISORY TO INCLUDE THE WRN AND SRN DACKS...LAKE GEORGE NRN
SARATOGA REGION...AND SRN VT...AS WELL AS NRN LITCHFIELD CTY CT.
BASICALLY OUR ENTIRE FCST AREA IS IN A WIND ADVISORY BY 10 PM
TONIGHT TO 3 PM TOMORROW...EXCEPT FOR THE MID HUDSON VALLEY /ERN
ULSTER...AND DUTCHESS COUNTIES/...AND SRN LITCHFIELD CTY CT.
THANKS FOR THE COLLABORATION WITH BOX AND OKX FOR THE ADDITION OF
NRN LITCHFIELD CTY. THE H850 WINDS RAMP UP TO 50-70 KTS
TONIGHT...INITIALLY NORTH AND WEST OF KALB PRIOR TO
MIDNIGHT...THEN THEY OVERSPREAD THE REGION. THE 925 HPA WINDS
INCREASE TO 35-50 KTS BTWN 06Z-12Z WITH STRONG COLD AIR ADVECTION
OCCURRING ACROSS THE REGION WITH THE PASSAGE OF THE COLD FRONT.
THE LATEST 18Z NAM40 GUIDANCE HAS H850 TEMPS FALL TO -10C TO -15C
BY 12Z. WE MAY HAVE OUR ACTUAL MAX TEMPS OCCUR AROUND OR SHORTLY
AFTER 12Z TOMORROW.
THERE WILL BE A PERIOD OF UPSLOPE SNOWFALL ALONG THE WRN SPINE OF
THE WRN DACKS...N-CNTRL TACONICS...AND THE SRN GREENS. THE SHOWERS
QUICKLY TRANSITION TO SNOW SHOWERS WITH THE FRONTAL PASSAGE BTWN
03Z-06Z FROM KALB NORTH AND WEST...AND 06Z-09Z SOUTH AND EAST. WE
ARE DEALING WITH A OPEN WAVE...AND THE PERIOD OF OROGRAPHIC
UPSLOPE SNOWFALL SHOULD BE QUICK WITH POSSIBLY 1 TO 4 INCHES
ACROSS THE SRN DACKS/WRN MOHAWK VALLEY...AND 1-2 INCHES OVER THE
SRN GREENS.
WE DID NOT ISSUE ANY LAKE EFFECT/WINTER WX HEADLINES AT THIS TIME.
AGAIN...THE LATEST HIRES WRF...AND HRRR SHOW A NARROW PERIOD WITH
THIS SNOWFALL WITH IT TRANSLATING TO SOME MULTIBANDS TOWARDS
DAYBREAK. WE WILL CONTINUE TO EVALUATE IF ANY HEADLINES ARE
NEEDED...BUT AT THIS TIME THE WINDS LOOK LIKE THE BIGGEST ISSUE.
EXPECT TEMPS TO FALL INTO THE TEENS OVER THE SRN DACKS...AND 20S
OVER MOST OF THE REST OF THE REGION...EXCEPT FOR THE THE MID
HUDSON VALLEY...AND SRN LITCHFIELD CTY WHERE SOME LOWER 30S ARE POSSIBLE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
TOMORROW...THE BUFKIT MOMENTUM TRANSFER PROFILES INDICATE WIND
ADVISORY GUSTS ARE STILL POSSIBLE INTO THE AFTERNOON...ESPECIALLY
IF WE MIX TO 875-900 HPA OR SO. IF WE MIX HIGHER...THEN WE COULD
APPROACH SOME 50 KT GUSTS. OVERALL...NW WIND GUSTS OF 45-55 MPH
ARE POSSIBLE UNTIL ABOUT 20Z. KPOU IS MARGINAL WITH THE GUST
POTENTIAL AROUND 35 KTS OR SO. WE KEPT THAT LOCATION OUT OF THE
WIND ADVISORY. BLUSTERY AND COLD CONDITIONS WILL PERSIST WITH
TEMPS FALLING IN THE 20S AND TEENS IN THE AFTERNOON WITH COLD
ADVECTION CONTINUING WITH H850 TEMPS FALLING TO -15C TO -20C. THE
NW FLOW FAVORS MULTIBANDS OVER CNTRL NY TOMORROW. SOME OF THE
NARROW MULTIBANDS CREEP INTO THE WRN MOHAWK VALLEY...AND ERN
CATSKILLS. A COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE. WE
TENDED TO DECREASE THE POPS TO SLIGHT OR LOW CHC VALUES OVER THE
SRN GREENS...NRN TACONICS...AND BERKSHIRES WITH THE BOUNDARY LAYER
DRYING OUT /WE ARE LOSING THE MOISTURE HERE/ AND THE MESOSCALE
GUIDANCE SHOWING LESS OF AN UPSLOPE EVENT.
IN THE LATE AFTERNOON...THE UPSTREAM SOUNDINGS OVER KYSR...AND
KRME SHOW THE SUBSIDENCE INVERSION LOWERING TO 4-5 KFT AGL
SQUELCHING ANY LAKE EFFECT SNOW.
WEDNESDAY NIGHT...HIGH PRESSURE QUICKLY RIDGES IN OVER NY AND NEW
ENGLAND WITH COLD AND DRY WEATHER. THE WINDS WILL SUBSIDE...AND
EXPECT DECENT RADIATIONAL COOLING WITH LOWS ZERO TO 10 BELOW OVER
THE LAKE GEORGE REGION...AND SOUTHERN ADIRONDACKS...SINGLE DIGITS
ELSEWHERE...EXPECT 10 TO 15F IN THE MID HUDSON VALLEY...AND SRN
LITCHFIELD CTY CT.
THU-THU NIGHT...ANOTHER SYSTEM APPROACHES FROM THE GREAT LAKES
REGION AND SRN ONTARIO FOR LATE THU. MID AND HIGH CLOUDS INCREASE
DURING THE LATE MORNING INTO THE EARLY PM...AS THE WARM ADVECTION
INCREASES. WE PLACE SOME SLIGHT TO LOW CHC POPS IN DURING THE PM
FOR SOME SCT SNOW SHOWERS OR LIGHT SNOW. THE WAVE PASSES WELL
NORTH OVER S-CNTRL QUEBEC...WITH ITS ASSOCIATED WARM AND COLD
FRONTS BRINGING SOME LIGHT SNOW OR SNOW SHOWERS TO REGION WITH
LIGHT SNOW ACCUMULATIONS OF A COATING TO AN INCH OR TWO. WE WENT
WITH THE HIGHEST POPS OVER THE NRN TIER THU NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
NO MAJOR SYSTEMS DURING THIS PERIOD...BUT AREAS OF CHC POPS FOR
MOST. THERE WILL BE WEAK HIGH PRESSURE AREAS INTERSPERSED BETWEEN
WEAK FRONTS/SYSTEMS. A RELATIVELY MODEST WARM-UP IS IN STORE DURING
THE WEEKEND. HIGH TEMPERATURES IN THE TEENS AND 20S ON FRIDAY WILL
BECOME HIGHS FROM THE MID 30S TO LOWER 50S BY MONDAY WHEN 540
1000-500 MB THICKNESSES WILL LIE JUST NORTH OF OUR ZONES. INDEED...
MONDAY WILL BE THE NICEST DAY OF THE PERIOD...WITH THE GREATEST
AMOUNT OF SUNSHINE AND LOWEST POPS. OVERNIGHT LOWS FROM THE MINUS
SINGLE DIGITS IN THE WESTERN ADIRONDACKS...TO THE LOWER 30S IN THE
MID HUDSON VALLEY...WILL MODERATE TO LOWS MOSTLY IN THE 30S SUNDAY
NIGHT AS THERE WILL BE NO REAL DIURNAL COOLING TREND GIVEN THE WARM
FRONT LIFTING THROUGH THE AREA.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A STRONG COLD FRONT WILL CROSS THE TAF SITES OVER THE NEXT 1-3
HOURS...PASSING KGFL WITHIN THE NEXT FEW MINUTES...KALB BETWEEN
0540Z-0550Z...AND KPOU CLOSER TO 07Z-08Z. A BRIEF PERIOD OF
LIGHT/MODERATE RAIN SHOWERS...AND POSSIBLE WIND GUSTS UP TO 35 KT
WILL BE POSSIBLE DURING THE FRONTAL PASSAGE. IN ITS WAKE...EXPECT
W WINDS THROUGH DAYBREAK AT 10-20 KT AND GUSTS TO 25-35
KT...ALTHOUGH STRONGER GUSTS WILL BE POSSIBLE AT KALB...ESP
NEARING DAYBREAK. WINDS WILL INCREASE FURTHER AROUND...AND SEVERAL
HOURS AFTER DAYBREAK...POSSIBLY THROUGH EARLY AFTERNOON...FROM THE
W TO NW...INCREASING TO 15-25 KT...WITH GUSTS OF 35-45 KT
POSSIBLE...STRONGEST AT KALB. WINDS WILL BECOME NW AND SUBSIDE
RAPIDLY BETWEEN 23Z/WED AND 03Z/THU...LAST AT KALB.
AS FOR PRECIPITATION...OTHER THAN THE BRIEF RAIN SHOWERS WITH THE
FRONTAL PASSAGE...THE NEXT CHC FOR PRECIP WILL BE POSSIBLE
ISOLATED/SCATTERED SNOW SHOWERS DEVELOPING TOWARD DAYBREAK...WITH
BEST CHC AT KALB...WITH ISOLATED/SCATTERED SNOW SHOWERS POSSIBLY
CONTINUING UNTIL MIDDAY WED. ANY SNOW SHOWERS MAY PRODUCE BRIEF
PERIODS OF MVFR/IFR VSBYS...AND COULD PRODUCE A DUSTING.
OTHERWISE...EXPECT MAINLY VFR LEVEL CLOUDS/VSBYS THROUGH 06Z/THU.
OUTLOOK...
WED NIGHT...VFR. NO SIG WX.
THU...MAINLY VFR. SLIGHT CHC -SHSN WITH MVFR POSSIBLE.
THU NIGHT...MVFR. CHC -SHSN AT KALB AND KPOU WITH -SHSN LIKELY AT
KGFL WITH IFR POSSIBLE.
FRI...VFR. NO SIG WX.
SAT...VFR WITH MVFR POSSIBLE. CHC -SHSN.
SUN...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
THE WEEKEND.
A COLD FRONT WILL MOVE THROUGH THIS EVENING WITH SOME SCATTERED
RAIN AND SNOW SHOWERS WITH LIGHT LIQUID EQUIVALENT AMOUNTS WELL
UNDER A QUARTER OF AN INCH. THE HIGHEST SNOW TALLIES WILL BE ALONG
THE WESTERN SLOPES OF THE SOUTHERN ADIRONDACKS...AND THE SOUTHERN
GREEN MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY WITH SNOWFALL AMOUNTS
OF 1 TO 4 INCHES.
COLD AND DRY WEATHER WILL PREVAIL LATE WEDNESDAY INTO THURSDAY MORNING.
A CLIPPER LOW MAY BRING SCATTERED SNOW SHOWERS OR LIGHT SNOW
THURSDAY NIGHT INTO FRIDAY. ANOTHER SYSTEM FOR THE FIRST HALF OF
THE WEEKEND MAY BRING SOME LIGHT SNOWFALL AGAIN.
ICE FORMATION OR THICKENING WILL SLOW DOWN THROUGH TONIGHT WITH A
BRIEF SPELL OF MILDER WEATHER. ICE FORMATION SHOULD INCREASE AGAIN
WEDNESDAY INTO THURSDAY AS TEMPERATURES FALL BACK WELL BELOW
FREEZING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR CTZ001.
NY...WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR NYZ039>043-
047>054-058>061-063-082>084.
HIGH WIND WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NYZ032-033-
038.
MA...WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR MAZ001-025.
VT...WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR VTZ013>015.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AVIATION...KL
AREA FORECAST DISCUSSION
NWS ALBANY NY
1203 AM EST WED JAN 18 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS MOVES ALONG
THE SAINT LAWRENCE RIVER VALLEY TONIGHT. THE COLD FRONT TO THE
SYSTEM WILL SWING ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND
OVERNIGHT...WITH SCATTERED SNOW SHOWERS...BLUSTERY...AND COLD
CONDITIONS FOR WEDNESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN
WEDNESDAY AFTERNOON INTO THURSDAY MORNING...AS A CLIPPER LOW WILL
BRING SOME SCATTERED SHOWERS SHOWERS LATE THURSDAY AFTERNOON THROUGH
THURSDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
VERY STRONG WINDS JUST OUTSIDE THE FORECAST AREA COULD SCRAPE THE
SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY EARY THHIS MORNING
AND INTO MID MORNING. SO...A HIGH WIND WARNING HAS BEEN ISSUED
THERE. THE PRESSURE RISE FALL COUPLET IS TRACKING NORTHEAST ALONG
AND JUST NORTH OF THE U.S. CANADIAN BORDER WHICH IMPLIES THE
STRONGEST WINDS MAY JUST MISS THE SOUTHERN ADIRONDACKS...BUT CLOSE
ENOUGH WHERE IS WOULD BE BEST TO WARN PEOPLE OF THE POSSIBILITY OF
DAMAGING WINDS JUST IN CASE. OF COURSE THE WIND ADVISORY IS STILL
IN EFFECT FOR OTHER AREAS.
JUST SOME MINOR ADJUSTMENTS TO TEMPERATURES BASED ON CURRENT
OBSERVATIONS AND TRENDS.
PREV AFD BELOW...
AS OF 930 PM...FORECAST ON TRACK. UPDATED POPS TO TIME COLD FRONT
AND SHOWERS ACROSS FORECAST AREA. HAVE LIKELY POPS ALONG BOUNDARY.
WINDS WILL SHIFT AND INCREASE BECOMING GUSTY WITH THE FRONTAL
PASSAGE. ADJUSTED TEMPERATURES AND DEW POINTS BASED ON OBSERVATIONAL
DATA.
AS OF 630 PM EST...WE WILL BE ALLOWING THE WINTER WX ADVISORY FOR
THE MIXTURE OF SLEET AND FREEZING RAIN TO EXPIRE AT 7 PM. THE
MESONET OBSERVATIONS SHOW TEMPERATURES HAVE MOSTLY RISEN ABOVE
FREEZING AT THIS TIME...AND THE BATCH OF PRECIPITATION HAS MOVED
WELL EAST OF THE REGION. WE HAVE TRIED TO TIME THE SHOWERS IN
AHEAD OF THE COLD FRONT. A NARROW COLD FRONTAL RAIN BAND HAS
DEVELOPED AHEAD OF THE FRONT OVER WRN NY WITH SOME STRONG TO
SEVERE CONVECTION. HOWEVER...WE BELIEVE THIS SHOULD WEAKEN OVER
THE NEXT FEW HOURS. WE WILL CONTINUE WITH THE WIND ADVISORY OVER
THE FORECAST AREA WITH GUSTS TO 50-55 MPH. WE WILL CONTINUE TO
MONITOR THE UPSTREAM OBSERVATIONS IF ANY UPGRADE TO A HIGH WIND
WARNING IS NECESSARY. OVERALL...HAVE PCPN CHANGING FROM RAIN TO
SNOW SHOWERS SHORTLY BEFORE MIDNIGHT NORTH AND WEST OF THE CAPITAL
REGION....AND SOUTH AND EAST BTWN 06Z-09Z. THE SHOWALTER VALUES
ARE GENERALLY +1 TO +3C AHEAD OF THE FRONT...SO WE WILL NOT BE
INCLUDING THUNDER AT THIS TIME. WE WILL ADD SOME PATCHY FOG OVER
THE MID HUDSON VALLEY...AND NW CT PRIOR TO MIDNIGHT TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM...IT HAS BEEN ANOTHER ACTIVE AND BUSY DAY ACROSS THE
ALY FORECAST AREA. THE NRN TIER HAS HAD MANY LOCATIONS HUNG UP IN
THE UPPER 20S TO NEAR THE FREEZING MARK IN THE THE MID TO LATE
PM...AS THE CURRENT AREA OF PCPN ON THE KENX/NORTHEAST MOSAIC
RADAR HAS PRODUCED PERIODS OF FREEZING RAIN. WE HAD ONE REPORT
COME IN AT 3 PM IN FAIRFIELD OF HERKIMER COUNTY WITH TWO TENTHS OF
AN INCH OF ICE...AND A TEMP OF 31F. THE POTENT LOW PRESSURE SYSTEM
APPROACHING FROM JUST NORTHEAST OF LAKE ERIE THIS HOUR HAS A
DOUBLE WARM FRONT STRUCTURE. THE FIRST WEAK WARM FRONT WENT
THROUGH MOST THE REGION THIS MORNING. A SECOND WARM FRONT OR
THERMAL TROUGH WITH A SHORT-WAVE IN THE SW FLOW HAS FOCUSED THE
AREA OF PCPN. WE WILL BE EXTENDING THE WINTER WEATHER ADVISORY FOR
THE ERN DACKS...LAKE GEORGE-NRN SARATOGA REGION...AND SRN VT
UNTIL 7 PM. WE WILL BE EXPIRING HERKIMER...MONTGOMERY...SRN FULTON
COUNTIES AT 4 PM...AND PHRASE IT AS POCKETS OF FREEZING RAIN...AS
THE LATEST MESONET SITES SHOW TEMPERATURES WARMING ABOVE FREEZING
AT THIS TIME IN THESE SPOTS.
THE OTHER BIG ISSUE TONIGHT IS THE SFC CYCLONE MOVING NORTHEAST
ALONG THE ST LAWRENCE RIVER VALLEY. THE NAM20 INDICATES AN
IMPRESSIVE ISALLOBARIC RISE-FALL PRESSURE COUPLET. WE ARE
EXPECTING 10-12 HPA/3 HRS RISES MOVING NEAR MASSENA WITH THE
DEEPENING AND INTENSIFYING WAVE EARLY THIS EVENING. THE GREATEST PRESSURE
RISES IN OUR AREA ARE 5-6 HPA/3 HRS. WE HAVE EXPANDED THE WIND
ADVISORY TO INCLUDE THE WRN AND SRN DACKS...LAKE GEORGE NRN
SARATOGA REGION...AND SRN VT...AS WELL AS NRN LITCHFIELD CTY CT.
BASICALLY OUR ENTIRE FCST AREA IS IN A WIND ADVISORY BY 10 PM
TONIGHT TO 3 PM TOMORROW...EXCEPT FOR THE MID HUDSON VALLEY /ERN
ULSTER...AND DUTCHESS COUNTIES/...AND SRN LITCHFIELD CTY CT.
THANKS FOR THE COLLABORATION WITH BOX AND OKX FOR THE ADDITION OF
NRN LITCHFIELD CTY. THE H850 WINDS RAMP UP TO 50-70 KTS
TONIGHT...INITIALLY NORTH AND WEST OF KALB PRIOR TO
MIDNIGHT...THEN THEY OVERSPREAD THE REGION. THE 925 HPA WINDS
INCREASE TO 35-50 KTS BTWN 06Z-12Z WITH STRONG COLD AIR ADVECTION
OCCURRING ACROSS THE REGION WITH THE PASSAGE OF THE COLD FRONT.
THE LATEST 18Z NAM40 GUIDANCE HAS H850 TEMPS FALL TO -10C TO -15C
BY 12Z. WE MAY HAVE OUR ACTUAL MAX TEMPS OCCUR AROUND OR SHORTLY
AFTER 12Z TOMORROW.
THERE WILL BE A PERIOD OF UPSLOPE SNOWFALL ALONG THE WRN SPINE OF
THE WRN DACKS...N-CNTRL TACONICS...AND THE SRN GREENS. THE SHOWERS
QUICKLY TRANSITION TO SNOW SHOWERS WITH THE FRONTAL PASSAGE BTWN
03Z-06Z FROM KALB NORTH AND WEST...AND 06Z-09Z SOUTH AND EAST. WE
ARE DEALING WITH A OPEN WAVE...AND THE PERIOD OF OROGRAPHIC
UPSLOPE SNOWFALL SHOULD BE QUICK WITH POSSIBLY 1 TO 4 INCHES
ACROSS THE SRN DACKS/WRN MOHAWK VALLEY...AND 1-2 INCHES OVER THE
SRN GREENS.
WE DID NOT ISSUE ANY LAKE EFFECT/WINTER WX HEADLINES AT THIS TIME.
AGAIN...THE LATEST HIRES WRF...AND HRRR SHOW A NARROW PERIOD WITH
THIS SNOWFALL WITH IT TRANSLATING TO SOME MULTIBANDS TOWARDS
DAYBREAK. WE WILL CONTINUE TO EVALUATE IF ANY HEADLINES ARE
NEEDED...BUT AT THIS TIME THE WINDS LOOK LIKE THE BIGGEST ISSUE.
EXPECT TEMPS TO FALL INTO THE TEENS OVER THE SRN DACKS...AND 20S
OVER MOST OF THE REST OF THE REGION...EXCEPT FOR THE THE MID
HUDSON VALLEY...AND SRN LITCHFIELD CTY WHERE SOME LOWER 30S ARE POSSIBLE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
TOMORROW...THE BUFKIT MOMENTUM TRANSFER PROFILES INDICATE WIND
ADVISORY GUSTS ARE STILL POSSIBLE INTO THE AFTERNOON...ESPECIALLY
IF WE MIX TO 875-900 HPA OR SO. IF WE MIX HIGHER...THEN WE COULD
APPROACH SOME 50 KT GUSTS. OVERALL...NW WIND GUSTS OF 45-55 MPH
ARE POSSIBLE UNTIL ABOUT 20Z. KPOU IS MARGINAL WITH THE GUST
POTENTIAL AROUND 35 KTS OR SO. WE KEPT THAT LOCATION OUT OF THE
WIND ADVISORY. BLUSTERY AND COLD CONDITIONS WILL PERSIST WITH
TEMPS FALLING IN THE 20S AND TEENS IN THE AFTERNOON WITH COLD
ADVECTION CONTINUING WITH H850 TEMPS FALLING TO -15C TO -20C. THE
NW FLOW FAVORS MULTIBANDS OVER CNTRL NY TOMORROW. SOME OF THE
NARROW MULTIBANDS CREEP INTO THE WRN MOHAWK VALLEY...AND ERN
CATSKILLS. A COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE. WE
TENDED TO DECREASE THE POPS TO SLIGHT OR LOW CHC VALUES OVER THE
SRN GREENS...NRN TACONICS...AND BERKSHIRES WITH THE BOUNDARY LAYER
DRYING OUT /WE ARE LOSING THE MOISTURE HERE/ AND THE MESOSCALE
GUIDANCE SHOWING LESS OF AN UPSLOPE EVENT.
IN THE LATE AFTERNOON...THE UPSTREAM SOUNDINGS OVER KYSR...AND
KRME SHOW THE SUBSIDENCE INVERSION LOWERING TO 4-5 KFT AGL
SQUELCHING ANY LAKE EFFECT SNOW.
WEDNESDAY NIGHT...HIGH PRESSURE QUICKLY RIDGES IN OVER NY AND NEW
ENGLAND WITH COLD AND DRY WEATHER. THE WINDS WILL SUBSIDE...AND
EXPECT DECENT RADIATIONAL COOLING WITH LOWS ZERO TO 10 BELOW OVER
THE LAKE GEORGE REGION...AND SOUTHERN ADIRONDACKS...SINGLE DIGITS
ELSEWHERE...EXPECT 10 TO 15F IN THE MID HUDSON VALLEY...AND SRN
LITCHFIELD CTY CT.
THU-THU NIGHT...ANOTHER SYSTEM APPROACHES FROM THE GREAT LAKES
REGION AND SRN ONTARIO FOR LATE THU. MID AND HIGH CLOUDS INCREASE
DURING THE LATE MORNING INTO THE EARLY PM...AS THE WARM ADVECTION
INCREASES. WE PLACE SOME SLIGHT TO LOW CHC POPS IN DURING THE PM
FOR SOME SCT SNOW SHOWERS OR LIGHT SNOW. THE WAVE PASSES WELL
NORTH OVER S-CNTRL QUEBEC...WITH ITS ASSOCIATED WARM AND COLD
FRONTS BRINGING SOME LIGHT SNOW OR SNOW SHOWERS TO REGION WITH
LIGHT SNOW ACCUMULATIONS OF A COATING TO AN INCH OR TWO. WE WENT
WITH THE HIGHEST POPS OVER THE NRN TIER THU NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
NO MAJOR SYSTEMS DURING THIS PERIOD...BUT AREAS OF CHC POPS FOR
MOST. THERE WILL BE WEAK HIGH PRESSURE AREAS INTERSPERSED BETWEEN
WEAK FRONTS/SYSTEMS. A RELATIVELY MODEST WARM-UP IS IN STORE DURING
THE WEEKEND. HIGH TEMPERATURES IN THE TEENS AND 20S ON FRIDAY WILL
BECOME HIGHS FROM THE MID 30S TO LOWER 50S BY MONDAY WHEN 540
1000-500 MB THICKNESSES WILL LIE JUST NORTH OF OUR ZONES. INDEED...
MONDAY WILL BE THE NICEST DAY OF THE PERIOD...WITH THE GREATEST
AMOUNT OF SUNSHINE AND LOWEST POPS. OVERNIGHT LOWS FROM THE MINUS
SINGLE DIGITS IN THE WESTERN ADIRONDACKS...TO THE LOWER 30S IN THE
MID HUDSON VALLEY...WILL MODERATE TO LOWS MOSTLY IN THE 30S SUNDAY
NIGHT AS THERE WILL BE NO REAL DIURNAL COOLING TREND GIVEN THE WARM
FRONT LIFTING THROUGH THE AREA.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
STEADY PRECIPITATION MOVED OFF TO OUR EAST LATE TUESDAY AFTERNOON.
THE AREA IS NOW IN A PRECIPITATION LULL...WAITING ON APPROACHING
FRONTAL BOUNDARY. THE COLD FRONT IS MOVING ACROSS WESTERN NEW YORK
WITH THE SURFACE LOW MOVING NORTHEASTWARD ACROSS LAKE ONTARIO. LARGE
PRESSURE FALLS ARE OCCURRING JUST TO WEST OF THE LOW PRESSURE
CENTER. WINDS WILL SHIFT TO THE SOUTHWEST THEN WEST WITH PASSAGE
OF THE COLD FRONT AND BECOME STRONG AND GUSTY. AT THIS TIME...THERE
IS A LINE OF CONVECTION MOVING ACROSS WESTERN NEW YORK PRODUCING
VERY STRONG WIND GUSTS AND SOME DAMAGE...REFER TO NWS BUFFALO`S
PRELIMINARY LOCAL STORM REPORT (BUFLSRBUF) FOR DETAILS. EXPECT
THIS CONVECTION TO WEAKEN AS IT MOVES ACROSS THE STATE AND
ENCOUNTERS COLDER AND MORE STABLE AIR. HAVE ADDRESSED THE THREAT
FOR SHOWERS WITH THE COLD FRONT IN TAFS WITH VICINITY SHOWERS.
IFR CONDITIONS WILL IMPROVE TO MVFR THIS EVENING AS THE FRONT
APPROACHES WITH AN IMPROVEMENT TO VFR IN ITS WAKE. HOWEVER...MVFR
IS EXPECTED WITH SHOWER ACTIVITY.
HAVE A STRONG LOW LEVEL JET MOVING ACROSS AREA SO HAVE ADDED LOW
LEVEL SHEAR TO KGFL AND KPOU WHERE HAS LIGHT SURFACE WINDS.
OUTLOOK...
WED NIGHT...VFR. NO SIG WX.
THU...MAINLY VFR. SLIGHT CHC -SHSN WITH MVFR POSSIBLE.
THU NIGHT...MVFR. CHC -SHSN AT KALB AND KPOU WITH -SHSN LIKELY AT
KGFL WITH IFR POSSIBLE.
FRI...VFR. NO SIG WX.
SAT...VFR WITH MVFR POSSIBLE. CHC -SHSN.
SUN...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
THE WEEKEND.
A COLD FRONT WILL MOVE THROUGH THIS EVENING WITH SOME SCATTERED
RAIN AND SNOW SHOWERS WITH LIGHT LIQUID EQUIVALENT AMOUNTS WELL
UNDER A QUARTER OF AN INCH. THE HIGHEST SNOW TALLIES WILL BE ALONG
THE WESTERN SLOPES OF THE SOUTHERN ADIRONDACKS...AND THE SOUTHERN
GREEN MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY WITH SNOWFALL AMOUNTS
OF 1 TO 4 INCHES.
COLD AND DRY WEATHER WILL PREVAIL LATE WEDNESDAY INTO THURSDAY MORNING.
A CLIPPER LOW MAY BRING SCATTERED SNOW SHOWERS OR LIGHT SNOW
THURSDAY NIGHT INTO FRIDAY. ANOTHER SYSTEM FOR THE FIRST HALF OF
THE WEEKEND MAY BRING SOME LIGHT SNOWFALL AGAIN.
ICE FORMATION OR THICKENING WILL SLOW DOWN THROUGH TONIGHT WITH A
BRIEF SPELL OF MILDER WEATHER. ICE FORMATION SHOULD INCREASE AGAIN
WEDNESDAY INTO THURSDAY AS TEMPERATURES FALL BACK WELL BELOW
FREEZING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WIND ADVISORY UNTIL 3 PM EST WEDNESDAY FOR CTZ001.
NY...WIND ADVISORY UNTIL 3 PM EST WEDNESDAY FOR NYZ039>043-047>054-
058>061-063-082>084.
HIGH WIND WARNING UNTIL 3 PM EST WEDNESDAY FOR NYZ032-033-038.
MA...WIND ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MAZ001-025.
VT...WIND ADVISORY UNTIL 3 PM EST WEDNESDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
906 PM EST THU JAN 19 2012
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT AS A LOW PRESSURE SYSTEM TRACKS
ACROSS SOUTHEASTERN CANADA. ITS ASSOCIATED COLD FRONT WILL SWING
THROUGH OUR AREA LATE TONIGHT. MORE HIGH PRESSURE WILL BUILD INTO
THE MID ATLANTIC FOR FRIDAY. OVER THE WEEKEND, LOW PRESSURE WILL
DELIVER UNSETTLED WEATHER TO THE REGION SATURDAY, FOLLOWED BY HIGH
PRESSURE SETTLING IN FOR SUNDAY. MORE LOW PRESSURE MAY AFFECT OUR
AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE GFS AND WRF-NMM INITIALIZATION LOOKED PRETTY GOOD OFF OF THE 12Z
SOUNDINGS WITH NEITHER MODEL FAVORED. THE ECMWF AND HRRR VERIFIED
THE BEST WITH THE QPF GEOGRAPHICAL EXTENT TO OUR WEST AT 18Z AND THE
FORMER WAS USED TO FINE TUNE THE WX GRIDS FOR TONIGHT. THE MODELS
TRENDED COLDER AND THUS LESS OF A GEOGRAPHICAL MENTION OF RAIN FOR
TONIGHT.
THERE HAS NOT BEEN MUCH OF A MODEL CHANGE WITH RESPECT TO FORCING
AND THE LACK OF MOISTURE WITH WHAT UNDER OTHER CIRCUMSTANCES COULD
HAVE BEEN A MORE DYNAMICAL SYSTEM. THE ACTIVE SNOW AREA TO OUR NW IS
IN THE EXIT REGION OF A 160KT JET WHICH IS FORECAST TO WEAKEN
TONIGHT, BUT STILL WILL PASS ACROSS THE NORTHERN PART OF OUR CWA.
THE ISENTROPIC LIFT (AT 280K) AND THETA E ADVT PART OF THIS EVENT IS
FORECAST TO PASS OFFSHORE BY 00Z. MOST OF THEIR WORK IS TO TRY TO
BRING SOME MSTR INTO OUR CWA, BUT THE SOURCE REGION TO OUR SW IS
QUITE DRY. SO WHEN THE EXIT RGN OF THE JET AND THE FCST DEEP LEVEL
QVEC CONVERGENCE ARRIVE, THE WAA PART OF THE PROGRAM IS OVER. FOR
BETTER OR WORSE THIS DISCONTINUITY GOES A LONG WAY TOWARD GENERATING
THE LOW QPF ALL OF THE MODELS ARE FORECASTING.
NEVERTHELESS GIVEN THE LAST COUPLE OF FEATURES, WE INCREASED POPS
FAR NORTH FOR WATER EQUIVALENTS WHICH WILL PROBABLY BE ONLY SEVERAL
HUNDREDTHS. A QUARTER OF AN INCH OR GREATER SNOW FOLLOWED THE .01
QPF OFF THE ECMWF. THE NEXT SLICE DOWN THROUGH THE I95 CORRIDOR
WE SUGGEST A DUSTING POSSIBLE BY MORNING. FARTHER SE, WARMER
ANTECEDENT SURFACE TEMPS AND LIGHTER INTENSITY MIGHT MIX IN SOME
RAIN, BUT REGARDLESS SHOULD RESULT IN NO EXPECTED DUSTINGS.
THE MODELS TRY TO SHOW A POSSIBLE SECOND QPF MAX ALONG THE NJ COAST
(A COUPLE OF HUNDREDTHS MAYBE) LATE. THIS IS RELATED TO ANOTHER QVEC
CONVERGENCE AREA TRYING TO CATCH UP TO THE PRE FRONTAL ENVIRONMENT.
REASON FOR A POP IN THE POPS TOWARD MORNING THERE.
BECAUSE OF THE SW FLOW AND CLOUDS PRECEDING THE COLD FRONT WE
PREFERRED THE SLIGHTLY HIGHER DATA SETS FOR MINS. THE OVERALL
STRENGTH OF THE FCST LLJ IS ABOUT 5-10 KTS LOWER THAN THE 00Z
SOUNDING RUN, SO WE LOWERED LAND BASED GUSTS EAST ABOUT THE SAME AMT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A QUIET AND SEASONABLY COLD DAY IS FORECAST FOR FRIDAY. THE SOUNDING
INVERSION NORTHWEST SINKS RATHER QUICKLY SO WE LIMITED THE MENTION
OF FLURRIES IN THE POCONOS TO EARLY. THE FORECAST CONVECTIVE
TEMPERATURES GET PRETTY HIGH, SO WE ARE NOT EXPECTING MUCH HOME
GROWN CUMULUS CLOUDS. BY THE AFTERNOON WE SHOULD START SEEING THE
CIRRUS CLOUDS ASSOCIATED WITH THE NEXT SYSTEM. BASED ON THE FORECAST
FULL SUN MACROS, THE SLIGHTLY WARMER GFS MOS WAS PREFERRED FOR
TEMPERATURES. THERE MAY BE SOME WIND GUSTS IN THE MORNING, BUT
OVERALL THE WINDS WILL BE CLOSER TO SEASONAL AVERAGE AND NOT AS
ROBUST AS THE PREVIOUS COLD FRONTAL PASSAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
ACTIVE WEATHER WILL START OFF THE LONG TERM PERIOD AS ORGANIZING LOW
PRESSURE TO OUR SOUTHWEST APPROACHES FRIDAY NIGHT AND MOVES OVER THE
REGION DURING SATURDAY. MODEL ANALYSIS AND LOOKING AT FCST SOUNDINGS
CONTINUE TO DEPICT THIS AS A MIXED PRECIPITATION EVENT WITH AMPLE
MOISTURE MOVING OVER THE AREA AND SUFFICIENT COLD AIR IN PLACE AT
THE SURFACE TO START THE EVENT. MOST OF THE FORECAST AREA WILL
LIKELY SEE LIGHT SNOW AT THE ONSET OF PRECIPITATION DURING THE EARLY
MORNING HOURS OF SATURDAY. BUT WITH WARM ADVECTION TAKING PLACE
DURING THE COURSE OF SATURDAY, A TRANSITION TO SLEET OR EVEN
FREEZING RAIN AND THEN TO RAIN APPEARS PROBABLE FROM LATE MORNING TO
AFTERNOON FOR OUR SOUTHERN AND CENTRAL COUNTIES. THE TRANSITION TO
WINTRY MIX MAY REACH THE LEHIGH VALLEY, BUT AREAS IN THE POCONOS AND
NORTHWEST NJ LOOK TO RECEIVE PRIMARILY SNOW FROM THIS EVENT, WITH
SEVERAL INCHES OF ACCUMULATION PROBABLE AT THIS TIME. A WINTER STORM
WATCH HAS BEEN ISSUED WITH THIS FORECAST PACKAGE FOR CARBON AND
MONROE COUNTIES IN PA AND SUSSEX COUNTY IN NJ AS ACCUMULATIONS
RANGING FROM 4 TO 7 INCHES ARE ANTICIPATED AT THIS TIME. THE EURO IS
A BIT SLOWER THAN THE GFS WITH THE PASSAGE OF THIS SYSTEM OVER THE
REGION, WITH PRECIPITATION PROGGED TO LAST LONGER INTO SATURDAY
NIGHT. THE GFS WAS FAVORED A BIT WITH THE FASTER ONSET OF
PRECIPITATION WITH THE EVENT, AND ITS ALSO NOTED THAT THE GFS HAS
TRENDED COLDER.
DURING SUNDAY, STRONG HIGH PRESSURE SPREADS SOUTHWEST FROM EASTERN
CANADA AS THE LOW PRESSURE SYSTEM PUSHES EAST AND OUT TO SEA.
QUIETER CONDITIONS GENERALLY ARE EXPECTED TO RETURN SUNDAY, ALTHOUGH
THE MODELS HINT AT THE POSSIBILITY OF A COLD AIR DAMMING SITUATION
DEVELOPING. THE ODDS ON THIS HAPPENING AS EARLY AS SUNDAY ARE NOT
GREAT, AND THE SUNDAY POPS WITH THIS FORECAST ARE LOW. ANOTHER LOW
PRESSURE SYSTEM IS EXPECTED TO AFFECT OUR FORECAST AREA AS EARLY AS
SUNDAY NIGHT IN THE ACTIVE PATTERN. THIS LOW PRESSURE ORGANIZES OVER
THE CENTRAL PLAINS STATES DURING SUNDAY AND TRACKS NORTHEASTWARD TO
THE GREAT LAKES REGION SUNDAY NIGHT THROUGH MONDAY. ITS ASSOCIATED
FRONTS WILL MOVE THROUGH OUR REGION MONDAY AND MONDAY NIGHT.
TEMPERATURES AND THERMAL FIELDS GENERALLY ARE MILD ENOUGH TO SUPPORT
RAIN WITH THE PASSAGE OF THIS SYSTEM, ALTHOUGH COLD AIR THANKS TO
THE RECEDING HIGH TO THE NORTHEAST MAY GENERATE A PERIOD OF SNOW
CHANGING TO FREEZING RAIN FOR A WHILE NORTH. THE EURO AGAIN IS
SLOWER THAN THE GFS WITH THE PROGRESSION OF THIS SYSTEM THROUGH THE
EASTERN STATES. HOWEVER, AT THIS TIME, IT APPEARS THAT THIS SYSTEM
PUSHES EAST OF OUR AREA OVERNIGHT MONDAY. AFTER THAT, THE MODELS ARE
QUITE DIVERGENT (EVEN WITHIN THEMSELVES FROM RUN TO RUN).
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LATEST 18Z TAFS KEEP A VFR FORECAST GOING, BUT CONFIDENCE IS
LOWEST AT KABE.
A RAPID INCREASE IN MID AND HIGH LEVEL CLOUDINESS WILL CONTINUE THE
REST OF THE AFTERNOON. AS THE HIGH MOVES OFFSHORE, THERE WILL BE A
WINDOW FOR SOME BREEZINESS AND GUSTS FOR AROUND 15 KT WERE
MAINTAINED.
FOR TONIGHT, SNOW SHOWERS AND FLURRIES ASSOCIATED WITH AN
APPROACHING COLD FRONT WILL WORK THEIR WAY INTO THE TERMINALS.
GREATEST CHANCE FOR MVFR AND MAYBE EVEN BRIEFLY VSBY RELATED IFR
RESTRICTIONS IS EXPECTED AT LOCAL AIRPORTS NORTH OF A KRDG-KABE-
KTTN LINE WHERE FCST MOISTURE IS DEEPEST. SO IF WE ARE TOO
OPTIMISTIC ABOUT OUR TERMINALS, KABE IS MOST VULNERABLE. CIGS ARE
FORECAST TO LOWER, BUT REMAIN VFR.
THE 18Z NAM CAME IN WITH AN AREA OF 40 KT SOUTHWEST WINDS AT H925
THAT MOVES OVER EACH OF THE TAF SITES FROM PNE SOUTH. IT LOOKS
LIKE IT SPENDS 3 TO 4 HOURS OVER EACH SITE STARTING AT AROUND 01Z
OVER THE DELAWARE VALLEY SITES AND 02Z OR 03Z OVER THE
SOUTHEASTERN SITES. A 23Z AIRCRAFT SOUNDING FROM IAD SHOWED
H925 SOUTHWEST WINDS THERE HAD INCREASED TO BETWEEN 30 AND 35 KT,
AND THAT WAS CONSISTENT WITH THE NAM`S FORECAST STRENGTHENING OF
THE H925 FLOW. WE THEREFORE PUT IN A FOUR-HOUR PERIOD OF LLWS AT
THE APPROPRIATE SITES OVER THE APPROPRIATE TIME.
THE COLD FRONT SHOULD CLEAR THE TERMINALS FROM AROUND 09Z TO 11Z FROM
WEST TO EAST AND END ANY SNOW CHANCES. THE GRADIENT BEHIND THE
FRONT IS NOT THAT STRONG AND GUSTS WERE ONLY INCLUDED AT OUR TWO
WINDIEST AIRPORTS, KPHL AND KACY.
VFR CONDITIONS WITH NO CIGS ARE THEN FORECAST TO RETURN DURING
THE DAYLIGHT MORNING.
OUTLOOK...
LOW PRESSURE APPROACHES AND MOVES OVER THE REGION FROM FRIDAY NIGHT
THROUGH SATURDAY, BRINGING THE POTENTIAL FOR MIXED WINTRY
PRECIPITATION TO THE FORECAST AREA. LOWER CEILINGS AND VISIBILITIES
ARE EXPECTED DURING THIS TIMEFRAME. DEPENDING ON HOW QUICKLY THE
SYSTEM EXITS THE REGION, LOWER CONDITIONS MAY EXTEND INTO EARLY
SUNDAY. THE NEXT LOW PRESSURE SYSTEM THAT MAY AFFECT THE AREA,
BRINGING RAIN ALONG WITH LOWERED CEILING AND VISIBILITY VALUES, IS
EXPECTED SUNDAY NIGHT TO MONDAY NIGHT.
&&
.MARINE...
THE INCREASING SW FLOW WAS BRINGING SMALL CRAFT CONDITIONS THIS
EVENING. THE LOW LEVEL JET OF AROUND 40 KT LIKELY WILL CAUSE
OCCASIONAL GUSTS TO GALE FORCE INTO THE EARLY PRE-DAWN HOURS OVER
PARTS OF DELAWARE BAY AND OUR SOUTHERN ATLANTIC WATERS. WE EXPECT
THIS TO LAST FOR LESS THAN SIX HOURS, AND WE WILL ISSUE A MWS AND
ADDRESS IT IN THE CWF AND THE MWW.
THERE WILL BE A LULL LATE AS THE COLD FRONT NEARS, BUT THEN COULD BE
A COUPLE OF HOUR WINDOW OF OPPORTUNITY FOR MORE SCA CONDITIONS IN
THE FRESH COLD AIR ADVECTION BEHIND THE COLD FRONT ON FRIDAY
MORNING. AS THE NEXT HIGH PRESSURE SYSTEM THEN NEARS, BOTH WINDS AND
SEAS SHOULD DROP BELOW SMALL CRAFT ADVISORY CRITERIA BY THE
AFTERNOON.
WITH LOW PRESSURE MOVING OVER THE AREA SATURDAY THROUGH SATURDAY
NIGHT, REACHING SMALL CRAFT ADVISORY CRITERIA FOR SEAS IS EXPECTED,
THANKS TO A PERSISTENT EAST TO NORTHEAST FLOW. THE ELEVATED SEAS IN
THE 5 TO 6 FOOT RANGE ON OUR WATERS ARE ANTICIPATED SATURDAY NIGHT
THROUGH SUNDAY, AND THE ELEVATED SEAS MAY EXTEND INTO MONDAY WITH
THE PASSAGE OF ANOTHER WEATHER SYSTEM. WINDS AND GUSTS MAY
OCCASIONALLY REACH ADVISORY LEVELS DURING THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR PAZ054-055.
NJ...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR NJZ001.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST FRIDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...DELISI/KLINE
AVIATION...DELISI/GIGI/KLINE
MARINE...DELISI/GIGI/KLINE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
635 PM EST THU JAN 19 2012
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT AS A LOW PRESSURE SYSTEM TRACKS
ACROSS SOUTHEASTERN CANADA. ITS ASSOCIATED COLD FRONT WILL SWING
THROUGH OUR AREA LATE TONIGHT. MORE HIGH PRESSURE WILL BUILD INTO
THE MID ATLANTIC FOR FRIDAY. OVER THE WEEKEND, LOW PRESSURE WILL
DELIVER UNSETTLED WEATHER TO THE REGION SATURDAY, FOLLOWED BY HIGH
PRESSURE SETTLING IN FOR SUNDAY. MORE LOW PRESSURE MAY AFFECT OUR
AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE GFS AND WRF-NMM INITIALIZATION LOOKED PRETTY GOOD OFF OF THE 12Z
SOUNDINGS WITH NEITHER MODEL FAVORED. THE ECMWF AND HRRR VERIFIED
THE BEST WITH THE QPF GEOGRAPHICAL EXTENT TO OUR WEST AT 18Z AND THE
FORMER WAS USED TO FINE TUNE THE WX GRIDS FOR TONIGHT. THE MODELS
TRENDED COLDER AND THUS LESS OF A GEOGRAPHICAL MENTION OF RAIN FOR
TONIGHT.
THERE HAS NOT BEEN MUCH OF A MODEL CHANGE WITH RESPECT TO FORCING
AND THE LACK OF MOISTURE WITH WHAT UNDER OTHER CIRCUMSTANCES COULD
HAVE BEEN A MORE DYNAMICAL SYSTEM. THE ACTIVE SNOW AREA TO OUR NW IS
IN THE EXIT REGION OF A 160KT JET WHICH IS FORECAST TO WEAKEN
TONIGHT, BUT STILL WILL PASS ACROSS THE NORTHERN PART OF OUR CWA.
THE ISENTROPIC LIFT (AT 280K) AND THETA E ADVT PART OF THIS EVENT IS
FORECAST TO PASS OFFSHORE BY 00Z. MOST OF THEIR WORK IS TO TRY TO
BRING SOME MSTR INTO OUR CWA, BUT THE SOURCE REGION TO OUR SW IS
QUITE DRY. SO WHEN THE EXIT RGN OF THE JET AND THE FCST DEEP LEVEL
QVEC CONVERGENCE ARRIVE, THE WAA PART OF THE PROGRAM IS OVER. FOR
BETTER OR WORSE THIS DISCONTINUITY GOES A LONG WAY TOWARD GENERATING
THE LOW QPF ALL OF THE MODELS ARE FORECASTING.
NEVERTHELESS GIVEN THE LAST COUPLE OF FEATURES, WE INCREASED POPS
FAR NORTH FOR WATER EQUIVALENTS WHICH WILL PROBABLY BE ONLY SEVERAL
HUNDREDTHS. A QUARTER OF AN INCH OR GREATER SNOW FOLLOWED THE .01
QPF OFF THE ECMWF. THE NEXT SLICE DOWN THROUGH THE I95 CORRIDOR
WE SUGGEST A DUSTING POSSIBLE BY MORNING. FARTHER SE, WARMER
ANTECEDENT SURFACE TEMPS AND LIGHTER INTENSITY MIGHT MIX IN SOME
RAIN, BUT REGARDLESS SHOULD RESULT IN NO EXPECTED DUSTINGS.
THE MODELS TRY TO SHOW A POSSIBLE SECOND QPF MAX ALONG THE NJ COAST
(A COUPLE OF HUNDREDTHS MAYBE) LATE. THIS IS RELATED TO ANOTHER QVEC
CONVERGENCE AREA TRYING TO CATCH UP TO THE PRE FRONTAL ENVIRONMENT.
REASON FOR A POP IN THE POPS TOWARD MORNING THERE.
BECAUSE OF THE SW FLOW AND CLOUDS PRECEDING THE COLD FRONT WE
PREFERRED THE SLIGHTLY HIGHER DATA SETS FOR MINS. THE OVERALL
STRENGTH OF THE FCST LLJ IS ABOUT 5-10 KTS LOWER THAN THE 00Z
SOUNDING RUN, SO WE LOWERED LAND BASED GUSTS EAST ABOUT THE SAME AMT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A QUIET AND SEASONABLY COLD DAY IS FORECAST FOR FRIDAY. THE SOUNDING
INVERSION NORTHWEST SINKS RATHER QUICKLY SO WE LIMITED THE MENTION
OF FLURRIES IN THE POCONOS TO EARLY. THE FORECAST CONVECTIVE
TEMPERATURES GET PRETTY HIGH, SO WE ARE NOT EXPECTING MUCH HOME
GROWN CUMULUS CLOUDS. BY THE AFTERNOON WE SHOULD START SEEING THE
CIRRUS CLOUDS ASSOCIATED WITH THE NEXT SYSTEM. BASED ON THE FORECAST
FULL SUN MACROS, THE SLIGHTLY WARMER GFS MOS WAS PREFERRED FOR
TEMPERATURES. THERE MAY BE SOME WIND GUSTS IN THE MORNING, BUT
OVERALL THE WINDS WILL BE CLOSER TO SEASONAL AVERAGE AND NOT AS
ROBUST AS THE PREVIOUS COLD FRONTAL PASSAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
ACTIVE WEATHER WILL START OFF THE LONG TERM PERIOD AS ORGANIZING LOW
PRESSURE TO OUR SOUTHWEST APPROACHES FRIDAY NIGHT AND MOVES OVER THE
REGION DURING SATURDAY. MODEL ANALYSIS AND LOOKING AT FCST SOUNDINGS
CONTINUE TO DEPICT THIS AS A MIXED PRECIPITATION EVENT WITH AMPLE
MOISTURE MOVING OVER THE AREA AND SUFFICIENT COLD AIR IN PLACE AT
THE SURFACE TO START THE EVENT. MOST OF THE FORECAST AREA WILL
LIKELY SEE LIGHT SNOW AT THE ONSET OF PRECIPITATION DURING THE EARLY
MORNING HOURS OF SATURDAY. BUT WITH WARM ADVECTION TAKING PLACE
DURING THE COURSE OF SATURDAY, A TRANSITION TO SLEET OR EVEN
FREEZING RAIN AND THEN TO RAIN APPEARS PROBABLE FROM LATE MORNING TO
AFTERNOON FOR OUR SOUTHERN AND CENTRAL COUNTIES. THE TRANSITION TO
WINTRY MIX MAY REACH THE LEHIGH VALLEY, BUT AREAS IN THE POCONOS AND
NORTHWEST NJ LOOK TO RECEIVE PRIMARILY SNOW FROM THIS EVENT, WITH
SEVERAL INCHES OF ACCUMULATION PROBABLE AT THIS TIME. A WINTER STORM
WATCH HAS BEEN ISSUED WITH THIS FORECAST PACKAGE FOR CARBON AND
MONROE COUNTIES IN PA AND SUSSEX COUNTY IN NJ AS ACCUMULATIONS
RANGING FROM 4 TO 7 INCHES ARE ANTICIPATED AT THIS TIME. THE EURO IS
A BIT SLOWER THAN THE GFS WITH THE PASSAGE OF THIS SYSTEM OVER THE
REGION, WITH PRECIPITATION PROGGED TO LAST LONGER INTO SATURDAY
NIGHT. THE GFS WAS FAVORED A BIT WITH THE FASTER ONSET OF
PRECIPITATION WITH THE EVENT, AND ITS ALSO NOTED THAT THE GFS HAS
TRENDED COLDER.
DURING SUNDAY, STRONG HIGH PRESSURE SPREADS SOUTHWEST FROM EASTERN
CANADA AS THE LOW PRESSURE SYSTEM PUSHES EAST AND OUT TO SEA.
QUIETER CONDITIONS GENERALLY ARE EXPECTED TO RETURN SUNDAY, ALTHOUGH
THE MODELS HINT AT THE POSSIBILITY OF A COLD AIR DAMMING SITUATION
DEVELOPING. THE ODDS ON THIS HAPPENING AS EARLY AS SUNDAY ARE NOT
GREAT, AND THE SUNDAY POPS WITH THIS FORECAST ARE LOW. ANOTHER LOW
PRESSURE SYSTEM IS EXPECTED TO AFFECT OUR FORECAST AREA AS EARLY AS
SUNDAY NIGHT IN THE ACTIVE PATTERN. THIS LOW PRESSURE ORGANIZES OVER
THE CENTRAL PLAINS STATES DURING SUNDAY AND TRACKS NORTHEASTWARD TO
THE GREAT LAKES REGION SUNDAY NIGHT THROUGH MONDAY. ITS ASSOCIATED
FRONTS WILL MOVE THROUGH OUR REGION MONDAY AND MONDAY NIGHT.
TEMPERATURES AND THERMAL FIELDS GENERALLY ARE MILD ENOUGH TO SUPPORT
RAIN WITH THE PASSAGE OF THIS SYSTEM, ALTHOUGH COLD AIR THANKS TO
THE RECEDING HIGH TO THE NORTHEAST MAY GENERATE A PERIOD OF SNOW
CHANGING TO FREEZING RAIN FOR A WHILE NORTH. THE EURO AGAIN IS
SLOWER THAN THE GFS WITH THE PROGRESSION OF THIS SYSTEM THROUGH THE
EASTERN STATES. HOWEVER, AT THIS TIME, IT APPEARS THAT THIS SYSTEM
PUSHES EAST OF OUR AREA OVERNIGHT MONDAY. AFTER THAT, THE MODELS ARE
QUITE DIVERGENT (EVEN WITHIN THEMSELVES FROM RUN TO RUN).
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LATEST 18Z TAFS KEEP A VFR FORECAST GOING, BUT CONFIDENCE IS
LOWEST AT KABE.
A RAPID INCREASE IN MID AND HIGH LEVEL CLOUDINESS WILL CONTINUE THE
REST OF THE AFTERNOON. AS THE HIGH MOVES OFFSHORE, THERE WILL BE A
WINDOW FOR SOME BREEZINESS AND GUSTS FOR AROUND 15 KT WERE
MAINTAINED.
FOR TONIGHT, SNOW SHOWERS AND FLURRIES ASSOCIATED WITH AN
APPROACHING COLD FRONT WILL WORK THEIR WAY INTO THE TERMINALS.
GREATEST CHANCE FOR MVFR AND MAYBE EVEN BRIEFLY VSBY RELATED IFR
RESTRICTIONS IS EXPECTED AT LOCAL AIRPORTS NORTH OF A KRDG-KABE-
KTTN LINE WHERE FCST MOISTURE IS DEEPEST. SO IF WE ARE TOO
OPTIMISTIC ABOUT OUR TERMINALS, KABE IS MOST VULNERABLE. CIGS ARE
FORECAST TO LOWER, BUT REMAIN VFR.
THE 18Z NAM CAME IN WITH AN AREA OF 40 KT SOUTHWEST WINDS AT H925
THAT MOVES OVER EACH OF THE TAF SITES FROM PNE SOUTH. IT LOOKS
LIKE IT SPENDS 3 TO 4 HOURS OVER EACH SITE STARTING AT AROUND 01Z
OVER THE DELAWARE VALLEY SITES AND 02Z OR 03Z OVER THE
SOUTHEASTERN SITES. A 23Z AIRCRAFT SOUNDING FROM IAD SHOWED
H925 SOUTHWEST WINDS THERE HAD INCREASED TO BETWEEN 30 AND 35 KT,
AND THAT WAS CONSISTENT WITH THE NAM`S FORECAST STRENGTHENING OF
THE H925 FLOW. WE THEREFORE PUT IN A FOUR-HOUR PERIOD OF LLWS AT
THE APPROPRIATE SITES OVER THE APPROPRIATE TIME.
THE COLD FRONT SHOULD CLEAR THE TERMINALS FROM AROUND 09Z TO 11Z FROM
WEST TO EAST AND END ANY SNOW CHANCES. THE GRADIENT BEHIND THE
FRONT IS NOT THAT STRONG AND GUSTS WERE ONLY INCLUDED AT OUR TWO
WINDIEST AIRPORTS, KPHL AND KACY.
VFR CONDITIONS WITH NO CIGS ARE THEN FORECAST TO RETURN DURING
THE DAYLIGHT MORNING.
OUTLOOK...
LOW PRESSURE APPROACHES AND MOVES OVER THE REGION FROM FRIDAY NIGHT
THROUGH SATURDAY, BRINGING THE POTENTIAL FOR MIXED WINTRY
PRECIPITATION TO THE FORECAST AREA. LOWER CEILINGS AND VISIBILITIES
ARE EXPECTED DURING THIS TIMEFRAME. DEPENDING ON HOW QUICKLY THE
SYSTEM EXITS THE REGION, LOWER CONDITIONS MAY EXTEND INTO EARLY
SUNDAY. THE NEXT LOW PRESSURE SYSTEM THAT MAY AFFECT THE AREA,
BRINGING RAIN ALONG WITH LOWERED CEILING AND VISIBILITY VALUES, IS
EXPECTED SUNDAY NIGHT TO MONDAY NIGHT.
&&
.MARINE...
THE SMALL CRAFT ADVISORY WAS EXTENDED INTO FRIDAY MORNING FOR ALL
MARINE AREAS. THE INCREASING SW FLOW SHOULD BRING SMALL CRAFT
CONDITIONS TONIGHT. EVEN THOUGH THE WINDS ARE SOUTHWEST, IN THIS
INSTANCE IT STILL WILL BE COLDER AIR PASSING OVER WARMER WATER.
THERE WILL BE A LULL LATE AS THE COLD FRONT NEARS, BUT THEN COULD BE
A COUPLE OF HOUR WINDOW OF OPPORTUNITY FOR MORE SCA CONDITIONS IN
THE FRESH COLD AIR ADVECTION BEHIND THE COLD FRONT ON FRIDAY
MORNING. AS THE NEXT HIGH PRESSURE SYSTEM THEN NEARS, BOTH WINDS AND
SEAS SHOULD DROP BELOW SMALL CRAFT ADVISORY CRITERIA BY THE
AFTERNOON.
WITH LOW PRESSURE MOVING OVER THE AREA SATURDAY THROUGH SATURDAY
NIGHT, REACHING SMALL CRAFT ADVISORY CRITERIA FOR SEAS IS EXPECTED,
THANKS TO A PERSISTENT EAST TO NORTHEAST FLOW. THE ELEVATED SEAS IN
THE 5 TO 6 FOOT RANGE ON OUR WATERS ARE ANTICIPATED SATURDAY NIGHT
THROUGH SUNDAY, AND THE ELEVATED SEAS MAY EXTEND INTO MONDAY WITH
THE PASSAGE OF ANOTHER WEATHER SYSTEM. WINDS AND GUSTS MAY
OCCASIONALLY REACH ADVISORY LEVELS DURING THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR PAZ054-055.
NJ...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
EVENING FOR NJZ001.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST FRIDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...DELISI/KLINE
AVIATION...DELISI/GIGI/KLINE
MARINE...DELISI/GIGI/KLINE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
935 AM EST WED JAN 18 2012
.SYNOPSIS...
HIGH PRESSURE FROM THE OHIO VALLEY WILL BUILD EAST FOR TODAY AND
THURSDAY. A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON
THURSDAY NIGHT WITH ANOTHER AREA OF HIGH PRESSURE FOLLOWING FOR
FRIDAY. LOW PRESSURE APPROACHING FROM THE SOUTHWEST IS EXPECTED TO
PASS OVER OR NEAR OUR REGION ON SATURDAY. A WEAK AREA LOW PRESSURE
OR A FRONTAL BOUNDARY FROM THE WEST MAY ARRIVE ON MONDAY OR MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO BIG CHANGES WITH THE UPDATE, ADJUSTED SKY COVER A BIT UPWARD
WEST AND REPOSITIONED THE CHANCE OF MRNG FLURRIES A BIT FTHR TO
THE SW BASED ON UPSTREAM RADARS. TEMP FCSTS LOOK ON TRACK.
BEHIND THE FRONT...MOISTURE TRAPPED UNDER THE INVERSION IN THE
COLD AIR ADVECTION COULD LINGER IN THE HIGHER TERRAIN THIS
MORNING. IN ADDITION...IT IS POSSIBLE WITH THE FLOW THIS MORNING
THAT FLURRIES OR EVEN SNOW SHOWERS FROM LAKE ERIE THEN ONTARIO COULD
AFFECT THE HIGHER TERRAIN BEFORE THE INVERSION LOWERS FARTHER.
ELSEWHERE...THE NEW AIRMASS IS DRY...AND MODEL SOUNDINGS SUGGEST
THAT MOST PLACES COULD SEE CONVECTIVE TEMPERATURES REACHED. RIGHT
NOW...THE AIRMASS LOOKS DRY ENOUGH FOR MOSTLY SUNNY TO WORK SOUTH
AND EAST OF THE I-95 CORRIDOR. NORTH AND WEST...THERE COULD BE A
PERIOD OF BROKEN STRATOCUMULUS...AND PARTLY SUNNY COULD WORK
BETTER THERE.
THE STRONGEST WINDS SHOULD BE THIS MORNING WITH THE TIGHTEST
GRADIENT AND BEST MIXING IN THE COLD AIR ADVECTION. WHILE WINDS
DROP OFF SOME THIS AFTERNOON...MOST PLACES PROBABLY SEE GUSTS FOR
MUCH OF THE DAY. FOR THE THE MOST PART...HIGHS WERE BASED ON THE
MOS BLEND. AFTER TEMPERATURES DROP THIS MORNING IN THE WAKE OF THE
FRONT...THEY SHOULD RISE IN SPITE OF GOOD COLD AIR
ADVECTION...THEN START FALLING OFF LATER THIS AFTERNOON. THE
EXCEPTION HERE COULD BE THE SOUTHERN POCONOS AND NORTHWEST NEW
JERSEY...WHERE MOS SHOULD TEMPERATURES FALLING SLOWLY MOST OF THE
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LAST OF THE GRADIENT EXITS IN THE EVENING AS HIGH PRESSURE
BUILDS TOWARD THE AREA. WINDS SHOULD DROP OFF IN PROTECTED AREAS
QUICKLY ENOUGH THIS EVENING TO PROMOTE GOOD RADIATIONAL COOLING
(HELPS THAT THE AIR IS DRY AS WELL. HIGH CLOUDINESS AHEAD OF THE
NEXT SHORT WAVE IN THE FAST NORTHERN FLOW WILL OVERSPREAD THE
REGION...MAINLY AFTER MIDNIGHT.
THIS SHOULD BE ENOUGH TIME FOR COLDER LOCATIONS TO DROP A FEW
DEGREES BELOW THE COLDEST MOS NUMBERS FOR LOWS. ELSEWHERE...A
BLEND OF MOS NUMBERS WAS USED FOR LOWS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE IS FORECAST TO BE LOCATED OVER OUR REGION ON
THURSDAY MORNING AND IT SHOULD DRIFT OFF THE COAST DURING THE
COURSE OF THE DAY. HIGH AND MID LEVEL CLOUDS AHEAD OF OUR NEXT
WEATHER SYSTEM WILL LIKELY BEGIN TO OVERSPREAD OUR REGION DURING
THE AFTERNOON HOURS.
A MID LEVEL SHORT WAVE IS FORECAST TO PASS OVER THE NORTHEASTERN
STATES ON THURSDAY NIGHT. ITS ASSOCIATED COLD FRONT SHOULD PASS
THROUGH OUR FORECAST AREA AT THAT TIME, AS WELL. THERE WILL NOT BE
A GREAT DEAL OF MOISTURE ASSOCIATED WITH THE SYSTEM. HOWEVER, SNOW
SHOWERS AND FLURRIES ARE POSSIBLE IN MUCH OF OUR REGION. THE
BOUNDARY LAYER MAY BE A LITTLE TOO WARM TO SUPPORT ALL SNOW IN OUR
FAR SOUTHERN COUNTIES. NEVERTHELESS, LITTLE OR NO SNOW
ACCUMULATION IS ANTICIPATED EXCEPT PERHAPS ACROSS OUR NORTHERN
COUNTIES WHERE A FEW TENTHS OF AN INCH ARE POSSIBLE.
COLD HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR FRIDAY, WHICH
SHOULD BE THE COLDEST OF THE NEXT SEVERAL DAYS. HIGHS ARE FORECAST
TO BE MAINLY IN THE 30S, WITH READINGS REMAINING IN THE 20S IN THE
ELEVATED TERRAIN.
WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE SOUTHWEST ON
FRIDAY NIGHT AND IT SHOULD PASS OVER THE SOUTHERN PART OF OUR
FORECAST AREA ON SATURDAY. PRECIPITATION ASSOCIATED WITH THE
SYSTEM IS EXPECTED TO MOVE INTO OUR REGION LATE ON FRIDAY NIGHT.
INITIALLY, TEMPERATURES AT THE SURFACE AND ALOFT SHOULD BE COLD
ENOUGH TO SUPPORT SNOW IN ALL BUT OUR FAR SOUTHEASTERN COUNTIES.
HOWEVER, WITH WARM ADVECTION TAKING PLACE DURING THE COURSE OF THE
DAY, THE SNOW SHOULD CHANGE TO SLEET, THEN RAIN FROM SOUTH TO
NORTH WITH A WINTRY MIX POSSIBLY HOLDING THROUGH THE ENTIRE EVENT
IN THE LEHIGH VALLEY, THE POCONOS AND NORTHWESTERN NEW JERSEY.
THE 0000 UTC GFS AND THE 0000 UTC ECMWF DIVERGE A BIT WITH THEIR
SOLUTIONS BEYOND SATURDAY. FOR NOW, WE WILL INDICATE A BIT OF
PRECIPITATION LINGERING INTO SATURDAY NIGHT. WE WILL CARRY A
SLIGHT CHANCE FOR PRECIPITATION ON SUNDAY DUE TO THE UNCERTAINTY
IN THE FORECAST.
A WEAK SYSTEM FROM THE WEST MAY AFFECT OUR REGION ON MONDAY OR
MONDAY NIGHT, SO WE WILL KEEP A SLIGHT CHANCE OF RAIN FOR THOSE
TWO PERIODS.
IT DOES CONTINUE TO APPEAR AS THOUGH A WARMING TREND WILL TAKE
PLACE FOR THE EARLY PART OF THE NEW WEEK.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CONDITIONS ARE VFR THIS MORNING ACROSS THE REGION.
THE PRESSURE GRADIENT SHOULD PEAK THIS MORNING...WITH GUSTS AT
JUST ABOUT ALL TERMINALS REACHING 28 TO 32 KNOTS. AS THE GRADIENT
EASES A BIT THIS AFTERNOON...THE GUST POTENTIAL WILL DROP
BACK...AND AFTER 1700 UTC MOST TERMINAL LOCATIONS SHOULD SEE GUSTS
CLOSER TO 25 KNOTS. MODEL SOUNDINGS SUGGEST THAT CONVECTIVE
TEMPERATURES WILL BE REACHED IN THE NEW AIRMASS...SO VFR CEILINGS
ARE ONCE AGAIN POSSIBLE AT KRDG AND KABE. ELSEWHERE...THE
STRATOCUMULUS COVER IS EXPECTED TO BE SCATTERED.
AS HIGH PRESSURE BUILDS TOWARD THE AREA LATE THIS AFTERNOON...THE
GUSTINESS SHOULD END BETWEEN 2100 AND 2300 UTC. ANY CUMULUS SHOULD
BE RELEGATED TO THE HIGHER TERRAIN...AND ALL TERMINALS SHOULD BE
CLEAR BY 2300 UTC. VFR CONDITIONS ARE EXPECTED TONIGHT WITH MAINLY
HIGH CLOUDINESS LATER TONIGHT...ALONG WITH LIGHT AND VARIABLE
WINDS.
OUTLOOK...
MAINLY VFR CONDITIONS ARE EXPECTED FOR THURSDAY AND FRIDAY, EVEN
THOUGH A COLD FRONT FROM THE NORTHWEST MAY BRING SCATTERED LIGHT
SNOW SHOWERS OR FLURRIES ON THURSDAY NIGHT.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST MAY BRING A WINTRY
MIX OF PRECIPITATION TO OUR REGION FROM LATE FRIDAY NIGHT INTO
SATURDAY EVENING. LOW CEILING AND VISIBILITY VALUES ARE
ANTICIPATED. THE LOW CONDITIONS MAY CONTINUE INTO AT LEAST PART OF
SUNDAY DEPENDING UPON HOW QUICKLY THE SYSTEM MOVES OUT TO SEA.
&&
.MARINE...
WINDS BEHIND THE COLD FRONT WILL GUST TO GALE FORCE ACROSS ALL
WATERS. THE BEST GRADIENT AND MIXING POTENTIAL WILL LAST UNTIL
ABOUT 1500 UTC. THE LATEST HRRR MODEL SHOWS THE BEST GUSTS BETWEEN
1000 UTC AND 1400 UTC...AND THIS MAKES SENSE BASED ON WHAT IS
OCCURRING TO THE WEST OVER LAND. FOR NOW...THE GALE WARNING ENDING
TIME WILL NOT BE CHANGED BASED ON THE ABOVE...BUT THE ENDING TIME
COULD BE WHITTLED AWAY LATER THIS MORNING IF WINDS DROP OFF FAST
ENOUGH.
THE GRADIENT PROBABLY SUPPORT SMALL CRAFT WINDS AFTER 1800 UTC
THROUGH ABOUT 2200 UTC...AS MODEL SOUNDINGS SHOW DECENT GUST
POTENTIAL IN THE WEAKENING COLD AIR ADVECTION. SEAS RESPONDED TO
THE SOUTH SOUTHWEST FETCH OVER THE OCEAN WATERS. IT COULD TAKE THE
BETTER PART OF THE DAY TO COME DOWN BACK BELOW 5 FEET AS THE SWELL
SORTS ITSELF OUT.
WINDS AND SEAS WILL DROP BELOW SMALL CRAFT LEVELS DURING THE
EVENING AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE GRADIENT
SHOULD RELAX ENOUGH SO THAT WINDS COULD DROP BELOW 10 KNOTS TOWARD
DAYBREAK THURSDAY.
A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON THURSDAY
NIGHT. AS A RESULT, WIND GUSTS OF 25 TO 30 KNOTS ARE POSSIBLE FROM
THURSDAY NIGHT INTO FRIDAY.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST SHOULD PASS OVER OR
NEAR OUR REGION ON SATURDAY. THE SYSTEM SHOULD NOT BE STRONG
ENOUGH TO PRODUCE WIND GUSTS IN EXCESS OF 25 KNOTS. HOWEVER, A
PERSISTENT NORTHEASTERLY FLOW ASSOCIATED WITH THE LOW MAY CAUSE
WAVE HEIGHTS TO BUILD TO 5 TO 6 FEET OVER THE WEEKEND ON OUR OCEAN
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GIGI/HAYES
SHORT TERM...HAYES
LONG TERM...IOVINO
AVIATION...IOVINO/HAYES
MARINE...IOVINO/HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
708 AM EST WED JAN 18 2012
.SYNOPSIS...
A STRONG COLD FRONT PASSED THROUGH OUR REGION DURING THE NIGHT.
HIGH PRESSURE FROM THE WEST WILL FOLLOW FOR TODAY AND THURSDAY. A
COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON THURSDAY
NIGHT WITH ANOTHER AREA OF HIGH PRESSURE FOLLOWING FOR FRIDAY. LOW
PRESSURE APPROACHING FROM THE SOUTHWEST IS EXPECTED TO PASS OVER
OR NEAR OUR REGION ON SATURDAY. A WEAK AREA LOW PRESSURE OR A
FRONTAL BOUNDARY FROM THE WEST MAY ARRIVE ON MONDAY OR MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE WIND THIS
MORNING.
THE WIND ADVISORY WAS ALLOWED TO EXPIRE. THE BEST PRESSURE
GRADIENT HAS PASSED...AND IT SHOULD SLOWLY DROP INTO THE EARLY
AFTERNOON. AMDAR SOUNDINGS STILL SHOW 40 KNOT WINDS AT 4000
FEET...AND THIS PROBABLY RESULTS IN GUSTS TO 35 KNOTS THIS MORNING
ACROSS THE HIGHER TERRAIN.
ELSEWHERE...IT DOES NOT APPEAR AS THOUGH THE TRANSFER WILL BE AS
EFFICIENT IN THE FRONTAL ZONE...EVEN THOUGH AMDAR SOUNDINGS SHOW
WINDS NEAR 50 KNOTS AT ABOUT 3000 FEET. WINDS ARE PEAKING NEAR 35
KNOTS ACROSS SOUTH CENTRAL PENNSYLVANIA BEHIND THE FRONT...AND
THIS IS DO IT AS FAR AS GUSTS ACROSS THE REMAINDER OF THE AREA. AS
OF NOW...A WIND ADVISORY IS NOT BEING CONSIDERED.
THE MAIN AREA OF MID AND HIGH CLOUDINESS SHOULD BE SHUNTED EAST
AS A STRONG SHORT WAVE CLEARS THE MID LEVELS THIS MORNING. BEHIND
THE FRONT...MOISTURE TRAPPED UNDER THE INVERSION IN THE COLD AIR
ADVECTION COULD LINGER IN THE HIGHER TERRAIN THIS MORNING. IN
ADDITION...IT IS POSSIBLE WITH THE FLOW THIS MORNING THAT FLURRIES
OR EVEN SNOW SHOWERS FROM LAKE ERIE COULD AFFECT THE HIGHER
TERRAIN.
ELSEWHERE...THE NEW AIRMASS IS DRY...AND MODEL SOUNDINGS SUGGEST
THAT MOST PLACES COULD SEE CONVECTIVE TEMPERATURES REACHED. RIGHT
NOW...THE AIRMASS LOOKS DRY ENOUGH FOR MOSTLY SUNNY TO WORK SOUTH
AND EAST OF THE I-95 CORRIDOR. NORTH AND WEST...THERE COULD BE A
PERIOD OF BROKEN STRATOCUMULUS...AND PARTLY SUNNY COULD WORK
BETTER THERE.
THE STRONGEST WINDS SHOULD BE THIS MORNING WITH THE TIGHTEST
GRADIENT AND BEST MIXING IN THE COLD AIR ADVECTION. WHILE WINDS
DROP OFF SOME THIS AFTERNOON...MOST PLACES PROBABLY SEE GUSTS FOR
MUCH OF THE DAY. FOR THE THE MOST PART...HIGHS WERE BASED ON THE
MOS BLEND. AFTER TEMPERATURES DROP THIS MORNING IN THE WAKE OF THE
FRONT...THEY SHOULD RISE IN SPITE OF GOOD COLD AIR
ADVECTION...THEN START FALLING OFF LATER THIS AFTERNOON. THE
EXCEPTION HERE COULD BE THE SOUTHERN POCONOS AND NORTHWEST NEW
JERSEY...WHERE MOS SHOULD TEMPERATURES FALLING SLOWLY MOST OF THE
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LAST OF THE GRADIENT EXITS IN THE EVENING AS HIGH PRESSURE
BUILDS TOWARD THE AREA. WINDS SHOULD DROP OFF IN PROTECTED AREAS
QUICKLY ENOUGH THIS EVENING TO PROMOTE GOOD RADIATIONAL COOLING
(HELPS THAT THE AIR IS DRY AS WELL. HIGH CLOUDINESS AHEAD OF THE
NEXT SHORT WAVE IN THE FAST NORTHERN FLOW WILL OVERSPREAD THE
REGION...MAINLY AFTER MIDNIGHT.
THIS SHOULD BE ENOUGH TIME FOR COLDER LOCATIONS TO DROP A FEW
DEGREES BELOW THE COLDEST MOS NUMBERS FOR LOWS. ELSEWHERE...A
BLEND OF MOS NUMBERS WAS USED FOR LOWS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE IS FORECAST TO BE LOCATED OVER OUR REGION ON
THURSDAY MORNING AND IT SHOULD DRIFT OFF THE COAST DURING THE
COURSE OF THE DAY. HIGH AND MID LEVEL CLOUDS AHEAD OF OUR NEXT
WEATHER SYSTEM WILL LIKELY BEGIN TO OVERSPREAD OUR REGION DURING
THE AFTERNOON HOURS.
A MID LEVEL SHORT WAVE IS FORECAST TO PASS OVER THE NORTHEASTERN
STATES ON THURSDAY NIGHT. ITS ASSOCIATED COLD FRONT SHOULD PASS
THROUGH OUR FORECAST AREA AT THAT TIME, AS WELL. THERE WILL NOT BE
A GREAT DEAL OF MOISTURE ASSOCIATED WITH THE SYSTEM. HOWEVER, SNOW
SHOWERS AND FLURRIES ARE POSSIBLE IN MUCH OF OUR REGION. THE
BOUNDARY LAYER MAY BE A LITTLE TOO WARM TO SUPPORT ALL SNOW IN OUR
FAR SOUTHERN COUNTIES. NEVERTHELESS, LITTLE OR NO SNOW
ACCUMULATION IS ANTICIPATED EXCEPT PERHAPS ACROSS OUR NORTHERN
COUNTIES WHERE A FEW TENTHS OF AN INCH ARE POSSIBLE.
COLD HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR FRIDAY, WHICH
SHOULD BE THE COLDEST OF THE NEXT SEVERAL DAYS. HIGHS ARE FORECAST
TO BE MAINLY IN THE 30S, WITH READINGS REMAINING IN THE 20S IN THE
ELEVATED TERRAIN.
WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE SOUTHWEST ON
FRIDAY NIGHT AND IT SHOULD PASS OVER THE SOUTHERN PART OF OUR
FORECAST AREA ON SATURDAY. PRECIPITATION ASSOCIATED WITH THE
SYSTEM IS EXPECTED TO MOVE INTO OUR REGION LATE ON FRIDAY NIGHT.
INITIALLY, TEMPERATURES AT THE SURFACE AND ALOFT SHOULD BE COLD
ENOUGH TO SUPPORT SNOW IN ALL BUT OUR FAR SOUTHEASTERN COUNTIES.
HOWEVER, WITH WARM ADVECTION TAKING PLACE DURING THE COURSE OF THE
DAY, THE SNOW SHOULD CHANGE TO SLEET, THEN RAIN FROM SOUTH TO
NORTH WITH A WINTRY MIX POSSIBLY HOLDING THROUGH THE ENTIRE EVENT
IN THE LEHIGH VALLEY, THE POCONOS AND NORTHWESTERN NEW JERSEY.
THE 0000 UTC GFS AND THE 0000 UTC ECMWF DIVERGE A BIT WITH THEIR
SOLUTIONS BEYOND SATURDAY. FOR NOW, WE WILL INDICATE A BIT OF
PRECIPITATION LINGERING INTO SATURDAY NIGHT. WE WILL CARRY A
SLIGHT CHANCE FOR PRECIPITATION ON SUNDAY DUE TO THE UNCERTAINTY
IN THE FORECAST.
A WEAK SYSTEM FROM THE WEST MAY AFFECT OUR REGION ON MONDAY OR
MONDAY NIGHT, SO WE WILL KEEP A SLIGHT CHANCE OF RAIN FOR THOSE
TWO PERIODS.
IT DOES CONTINUE TO APPEAR AS THOUGH A WARMING TREND WILL TAKE
PLACE FOR THE EARLY PART OF THE NEW WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CONDITIONS ARE VFR EARLY THIS MORNING ACROSS THE REGION. A STRONG
COLD FRONT WILL EXIT THE AREA AFTER 0900 UTC. AS THE FRONT CROSSED
WESTERN AND CENTRAL PENNSYLVANIA...WINDS GUSTED TO 40 KNOTS.
HOWEVER...AS THE FRONT HAS MOVED EAST....AND NOW ENCOUNTERING
STRATIFIED AIR AHEAD OF IT...THE WIND GUSTS ARE NOT EXPECTED TO BE
QUITE AS STRONG WHEN THE FRONT CROSSES THE TERMINAL LOCATIONS.
THERE IS NOT MUCH IN THE WAY OF PRECIPITATION WITH THE FRONT...AND
VFR CEILINGS ARE POSSIBLE FOR A TIME THROUGH 1200 UTC...MAINLY AT
KABE AND KRDG.
THE PRESSURE GRADIENT SHOULD PEAK THIS MORNING...WITH GUSTS AT
JUST ABOUT ALL TERMINALS REACHING 28 TO 32 KNOTS. AS THE GRADIENT
EASES A BIT THIS AFTERNOON...THE GUST POTENTIAL WILL DROP
BACK...AND AFTER 1700 UTC MOST TERMINAL LOCATIONS SHOULD SEE GUSTS
CLOSER TO 25 KNOTS. MODEL SOUNDINGS SUGGEST THAT CONVECTIVE
TEMPERATURES WILL BE REACHED IN THE NEW AIRMASS...SO VFR CEILINGS
ARE ONCE AGAIN POSSIBLE AT KRDG AND KABE. ELSEWHERE...THE
STRATOCUMULUS COVER IS EXPECTED TO BE SCATTERED.
AS HIGH PRESSURE BUILDS TOWARD THE AREA LATE THIS AFTERNOON...THE
GUSTINESS SHOULD END BETWEEN 2100 AND 2300 UTC. ANY CUMULUS SHOULD
BE RELEGATED TO THE HIGHER TERRAIN...AND ALL TERMINALS SHOULD BE
CLEAR BY 2300 UTC. VFR CONDITIONS ARE EXPECTED TONIGHT WITH MAINLY
HIGH CLOUDINESS LATER TONIGHT...ALONG WITH LIGHT AND VARIABLE
WINDS.
OUTLOOK...
MAINLY VFR CONDITIONS ARE EXPECTED FOR THURSDAY AND FRIDAY, EVEN
THOUGH A COLD FRONT FROM THE NORTHWEST MAY BRING SCATTERED LIGHT
SNOW SHOWERS OR FLURRIES ON THURSDAY NIGHT.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST MAY BRING A WINTRY
MIX OF PRECIPITATION TO OUR REGION FROM LATE FRIDAY NIGHT INTO
SATURDAY EVENING. LOW CEILING AND VISIBILITY VALUES ARE
ANTICIPATED. THE LOW CONDITIONS MAY CONTINUE INTO AT LEAST PART OF
SUNDAY DEPENDING UPON HOW QUICKLY THE SYSTEM MOVES OUT TO SEA.
&&
.MARINE...
WINDS AHEAD OF THE COLD FRONT REACHED THE UPPER END OF THE SMALL
CRAFT RANGE ACROSS THE LOWER DELAWARE BAY AND SOUTHERN OCEAN
WATERS. THE DEPTH OF THE MIXED LAYER WAS FAIRLY HIGH FOR A WARM
AIR ADVECTION EVENT...BUT THIS WILL CHANGE WITH THE PASSAGE OF A
STRONG COLD FRONT.
WINDS WITH AND JUST BEHIND THE COLD FRONT WILL GUST TO GALE FORCE
ACROSS ALL WATERS. THE BEST GRADIENT AND MIXING POTENTIAL WILL
LAST UNTIL ABOUT 1500 UTC. THE LATEST HRRR MODEL SHOWS THE BEST
GUSTS BETWEEN 1000 UTC AND 1400 UTC...AND THIS MAKES SENSE BASED
ON WHAT IS OCCURRING TO THE WEST OVER LAND. FOR NOW...THE GALE
WARNING ENDING TIME WILL NOT BE CHANGED BASED ON THE ABOVE...BUT
THE ENDING TIME COULD BE WHITTLED AWAY LATER THIS MORNING IF WINDS
DROP OFF FAST ENOUGH.
THE GRADIENT PROBABLY SUPPORT SMALL CRAFT WINDS AFTER 1800 UTC
THROUGH ABOUT 2200 UTC...AS MODEL SOUNDINGS SHOW DECENT GUST
POTENTIAL IN THE WEAKENING COLD AIR ADVECTION. SEAS RESPONDED TO
THE SOUTH SOUTHWEST FETCH OVER THE OCEAN WATERS. IT COULD TAKE THE
BETTER PART OF THE DAY TO COME DOWN BACK BELOW 5 FEET AS THE SWELL
SORTS ITSELF OUT.
WINDS AND SEAS WILL DROP BELOW SMALL CRAFT LEVELS DURING THE
EVENING AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE GRADIENT
SHOULD RELAX ENOUGH SO THAT WINDS COULD DROP BELOW 10 KNOTS TOWARD
DAYBREAK THURSDAY.
A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON THURSDAY
NIGHT. AS A RESULT, WIND GUSTS OF 25 TO 30 KNOTS ARE POSSIBLE FROM
THURSDAY NIGHT INTO FRIDAY.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST SHOULD PASS OVER OR
NEAR OUR REGION ON SATURDAY. THE SYSTEM SHOULD NOT BE STRONG
ENOUGH TO PRODUCE WIND GUSTS IN EXCESS OF 25 KNOTS. HOWEVER, A
PERSISTENT NORTHEASTERLY FLOW ASSOCIATED WITH THE LOW MAY CAUSE
WAVE HEIGHTS TO BUILD TO 5 TO 6 FEET OVER THE WEEKEND ON OUR OCEAN
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...IOVINO
AVIATION...IOVINO/HAYES
MARINE...IOVINO/HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
344 AM EST WED JAN 18 2012
.SYNOPSIS...
A STRONG COLD FRONT PASSED THROUGH OUR REGION DURING THE NIGHT.
HIGH PRESSURE FROM THE WEST WILL FOLLOW FOR TODAY AND THURSDAY. A
COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON THURSDAY
NIGHT WITH ANOTHER AREA OF HIGH PRESSURE FOLLOWING FOR FRIDAY. LOW
PRESSURE APPROACHING FROM THE SOUTHWEST IS EXPECTED TO PASS OVER
OR NEAR OUR REGION ON SATURDAY. A WEAK AREA LOW PRESSURE OR A
FRONTAL BOUNDARY FROM THE WEST MAY ARRIVE ON MONDAY OR MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE WIND THIS
MORNING.
A STRONG COLD FRONT IS CROSSING THE FORECAST AREA EARLY THIS
MORNING. AMDAR SOUNDINGS ARE SHOWING 50 KNOTS NEAR THE TOP OF THE
INVERSION NEAR AND JUST BEHIND THE FRONT. BASED ON WHAT HAS
OCCURRED ACROSS WESTERN AND CENTRAL PENNSYLVANIA WITH THE
FRONT...TOP GUSTS OF 40 KNOTS ARE POSSIBLE BEFORE DAWN ACROSS THE
HIGHER TERRAIN.
KMPO REPORTED GUSTS TO 42 KNOTS AFTER THE PASSAGE OF THE FRONT.
SINCE THERE IS POTENTIAL...AND THE OBSERVATIONS ARE SHOWING SOME
OF THE POTENTIAL REACHING THE GROUND...A WIND ADVISORY WAS ISSUED
EARLIER FOR THE HIGHER TERRAIN. IT IS SCHEDULED TO EXPIRE AT 1200
UTC...AND ITS DISPOSITION WILL BE MONITORED AS THE EXPIRATION TIME
APPROACHES.
ELSEWHERE...IT DOES NOT APPEAR AS THOUGH THE TRANSFER WILL BE AS
EFFICIENT IN THE FRONTAL ZONE...EVEN THOUGH AMDAR SOUNDINGS SHOW
WINDS NEAR 50 KNOTS AT ABOUT 3000 FEET. WINDS ARE PEAKING NEAR 35
KNOTS ACROSS SOUTH CENTRAL PENNSYLVANIA BEHIND THE FRONT...AND
THIS IS DO IT AS FAR AS GUSTS ACROSS THE REMAINDER OF THE AREA. AS
OF NOW...A WIND ADVISORY IS NOT BEING CONSIDERED.
THE MAIN AREA OF MID AND HIGH CLOUDINESS SHOULD BE SHUNTED EAST
AS A STRONG SHORT WAVE CLEARS THE MID LEVELS THIS MORNING. BEHIND
THE FRONT...MOISTURE TRAPPED UNDER THE INVERSION IN THE COLD AIR
ADVECTION COULD LINGER IN THE HIGHER TERRAIN THIS MORNING. IN
ADDITION...IT IS POSSIBLE WITH THE FLOW THIS MORNING THAT FLURRIES
OR EVEN SNOW SHOWERS FROM LAKE ERIE COULD AFFECT THE HIGHER
TERRAIN.
ELSEWHERE...THE NEW AIRMASS IS DRY...AND MODEL SOUNDINGS SUGGEST
THAT MOST PLACES COULD SEE CONVECTIVE TEMPERATURES REACHED. RIGHT
NOW...THE AIRMASS LOOKS DRY ENOUGH FOR MOSTLY SUNNY TO WORK SOUTH
AND EAST OF THE I-95 CORRIDOR. NORTH AND WEST...THERE COULD BE A
PERIOD OF BROKEN STRATOCUMULUS...AND PARTLY SUNNY COULD WORK
BETTER THERE.
THE STRONGEST WINDS SHOULD BE THIS MORNING WITH THE TIGHTEST
GRADIENT AND BEST MIXING IN THE COLD AIR ADVECTION. WHILE WINDS
DROP OFF SOME THIS AFTERNOON...MOST PLACES PROBABLY SEE GUSTS FOR
MUCH OF THE DAY. FOR THE THE MOST PART...HIGHS WERE BASED ON THE
MOS BLEND. AFTER TEMPERATURES DROP THIS MORNING IN THE WAKE OF THE
FRONT...THEY SHOULD RISE IN SPITE OF GOOD COLD AIR
ADVECTION...THEN START FALLING OFF LATER THIS AFTERNOON. THE
EXCEPTION HERE COULD BE THE SOUTHERN POCONOS AND NORTHWEST NEW
JERSEY...WHERE MOS SHOULD TEMPERATURES FALLING SLOWLY MOST OF THE
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LAST OF THE GRADIENT EXITS IN THE EVENING AS HIGH PRESSURE
BUILDS TOWARD THE AREA. WINDS SHOULD DROP OFF IN PROTECTED AREAS
QUICKLY ENOUGH THIS EVENING TO PROMOTE GOOD RADIATIONAL COOLING
(HELPS THAT THE AIR IS DRY AS WELL. HIGH CLOUDINESS AHEAD OF THE
NEXT SHORT WAVE IN THE FAST NORTHERN FLOW WILL OVERSPREAD THE
REGION...MAINLY AFTER MIDNIGHT.
THIS SHOULD BE ENOUGH TIME FOR COLDER LOCATIONS TO DROP A FEW
DEGREES BELOW THE COLDEST MOS NUMBERS FOR LOWS. ELSEWHERE...A
BLEND OF MOS NUMBERS WAS USED FOR LOWS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE IS FORECAST TO BE LOCATED OVER OUR REGION ON
THURSDAY MORNING AND IT SHOULD DRIFT OFF THE COAST DURING THE
COURSE OF THE DAY. HIGH AND MID LEVEL CLOUDS AHEAD OF OUR NEXT
WEATHER SYSTEM WILL LIKELY BEGIN TO OVERSPREAD OUR REGION DURING
THE AFTERNOON HOURS.
A MID LEVEL SHORT WAVE IS FORECAST TO PASS OVER THE NORTHEASTERN
STATES ON THURSDAY NIGHT. ITS ASSOCIATED COLD FRONT SHOULD PASS
THROUGH OUR FORECAST AREA AT THAT TIME, AS WELL. THERE WILL NOT BE
A GREAT DEAL OF MOISTURE ASSOCIATED WITH THE SYSTEM. HOWEVER, SNOW
SHOWERS AND FLURRIES ARE POSSIBLE IN MUCH OF OUR REGION. THE
BOUNDARY LAYER MAY BE A LITTLE TOO WARM TO SUPPORT ALL SNOW IN OUR
FAR SOUTHERN COUNTIES. NEVERTHELESS, LITTLE OR NO SNOW
ACCUMULATION IS ANTICIPATED EXCEPT PERHAPS ACROSS OUR NORTHERN
COUNTIES WHERE A FEW TENTHS OF AN INCH ARE POSSIBLE.
COLD HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR FRIDAY, WHICH
SHOULD BE THE COLDEST OF THE NEXT SEVERAL DAYS. HIGHS ARE FORECAST
TO BE MAINLY IN THE 30S, WITH READINGS REMAINING IN THE 20S IN THE
ELEVATED TERRAIN.
WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE SOUTHWEST ON
FRIDAY NIGHT AND IT SHOULD PASS OVER THE SOUTHERN PART OF OUR
FORECAST AREA ON SATURDAY. PRECIPITATION ASSOCIATED WITH THE
SYSTEM IS EXPECTED TO MOVE INTO OUR REGION LATE ON FRIDAY NIGHT.
INITIALLY, TEMPERATURES AT THE SURFACE AND ALOFT SHOULD BE COLD
ENOUGH TO SUPPORT SNOW IN ALL BUT OUR FAR SOUTHEASTERN COUNTIES.
HOWEVER, WITH WARM ADVECTION TAKING PLACE DURING THE COURSE OF THE
DAY, THE SNOW SHOULD CHANGE TO SLEET, THEN RAIN FROM SOUTH TO
NORTH WITH A WINTRY MIX POSSIBLY HOLDING THROUGH THE ENTIRE EVENT
IN THE LEHIGH VALLEY, THE POCONOS AND NORTHWESTERN NEW JERSEY.
THE 0000 UTC GFS AND THE 0000 UTC ECMWF DIVERGE A BIT WITH THEIR
SOLUTIONS BEYOND SATURDAY. FOR NOW, WE WILL INDICATE A BIT OF
PRECIPITATION LINGERING INTO SATURDAY NIGHT. WE WILL CARRY A
SLIGHT CHANCE FOR PRECIPITATION ON SUNDAY DUE TO THE UNCERTAINTY
IN THE FORECAST.
A WEAK SYSTEM FROM THE WEST MAY AFFECT OUR REGION ON MONDAY OR
MONDAY NIGHT, SO WE WILL KEEP A SLIGHT CHANCE OF RAIN FOR THOSE
TWO PERIODS.
IT DOES CONTINUE TO APPEAR AS THOUGH A WARMING TREND WILL TAKE
PLACE FOR THE EARLY PART OF THE NEW WEEK.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CONDITIONS ARE VFR EARLY THIS MORNING ACROSS THE REGION. A STRONG
COLD FRONT WILL EXIT THE AREA AFTER 0900 UTC. AS THE FRONT CROSSED
WESTERN AND CENTRAL PENNSYLVANIA...WINDS GUSTED TO 40 KNOTS.
HOWEVER...AS THE FRONT HAS MOVED EAST....AND NOW ENCOUNTERING
STRATIFIED AIR AHEAD OF IT...THE WIND GUSTS ARE NOT EXPECTED TO BE
QUITE AS STRONG WHEN THE FRONT CROSSES THE TERMINAL LOCATIONS.
THERE IS NOT MUCH IN THE WAY OF PRECIPITATION WITH THE FRONT...AND
VFR CEILINGS ARE POSSIBLE FOR A TIME THROUGH 1200 UTC...MAINLY AT
KABE AND KRDG.
THE PRESSURE GRADIENT SHOULD PEAK THIS MORNING...WITH GUSTS AT
JUST ABOUT ALL TERMINALS REACHING 28 TO 32 KNOTS. AS THE GRADIENT
EASES A BIT THIS AFTERNOON...THE GUST POTENTIAL WILL DROP
BACK...AND AFTER 1700 UTC MOST TERMINAL LOCATIONS SHOULD SEE GUSTS
CLOSER TO 25 KNOTS. MODEL SOUNDINGS SUGGEST THAT CONVECTIVE
TEMPERATURES WILL BE REACHED IN THE NEW AIRMASS...SO VFR CEILINGS
ARE ONCE AGAIN POSSIBLE AT KRDG AND KABE. ELSEWHERE...THE
STRATOCUMULUS COVER IS EXPECTED TO BE SCATTERED.
AS HIGH PRESSURE BUILDS TOWARD THE AREA LATE THIS AFTERNOON...THE
GUSTINESS SHOULD END BETWEEN 2100 AND 2300 UTC. ANY CUMULUS SHOULD
BE RELEGATED TO THE HIGHER TERRAIN...AND ALL TERMINALS SHOULD BE
CLEAR BY 2300 UTC. VFR CONDITIONS ARE EXPECTED TONIGHT WITH MAINLY
HIGH CLOUDINESS LATER TONIGHT...ALONG WITH LIGHT AND VARIABLE
WINDS.
OUTLOOK...
MAINLY VFR CONDITIONS ARE EXPECTED FOR THURSDAY AND FRIDAY, EVEN
THOUGH A COLD FRONT FROM THE NORTHWEST MAY BRING SCATTERED LIGHT
SNOW SHOWERS OR FLURRIES ON THURSDAY NIGHT.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST MAY BRING A WINTRY
MIX OF PRECIPITATION TO OUR REGION FROM LATE FRIDAY NIGHT INTO
SATURDAY EVENING. LOW CEILING AND VISIBILITY VALUES ARE
ANTICIPATED. THE LOW CONDITIONS MAY CONTINUE INTO AT LEAST PART OF
SUNDAY DEPENDING UPON HOW QUICKLY THE SYSTEM MOVES OUT TO SEA.
&&
.MARINE...
WINDS AHEAD OF THE COLD FRONT REACHED THE UPPER END OF THE SMALL
CRAFT RANGE ACROSS THE LOWER DELAWARE BAY AND SOUTHERN OCEAN
WATERS. THE DEPTH OF THE MIXED LAYER WAS FAIRLY HIGH FOR A WARM
AIR ADVECTION EVENT...BUT THIS WILL CHANGE WITH THE PASSAGE OF A
STRONG COLD FRONT.
WINDS WITH AND JUST BEHIND THE COLD FRONT WILL GUST TO GALE FORCE
ACROSS ALL WATERS. THE BEST GRADIENT AND MIXING POTENTIAL WILL
LAST UNTIL ABOUT 1500 UTC. THE LATEST HRRR MODEL SHOWS THE BEST
GUSTS BETWEEN 1000 UTC AND 1400 UTC...AND THIS MAKES SENSE BASED
ON WHAT IS OCCURRING TO THE WEST OVER LAND. FOR NOW...THE GALE
WARNING ENDING TIME WILL NOT BE CHANGED BASED ON THE ABOVE...BUT
THE ENDING TIME COULD BE WHITTLED AWAY LATER THIS MORNING IF WINDS
DROP OFF FAST ENOUGH.
THE GRADIENT PROBABLY SUPPORT SMALL CRAFT WINDS AFTER 1800 UTC
THROUGH ABOUT 2200 UTC...AS MODEL SOUNDINGS SHOW DECENT GUST
POTENTIAL IN THE WEAKENING COLD AIR ADVECTION. SEAS RESPONDED TO
THE SOUTH SOUTHWEST FETCH OVER THE OCEAN WATERS. IT COULD TAKE THE
BETTER PART OF THE DAY TO COME DOWN BACK BELOW 5 FEET AS THE SWELL
SORTS ITSELF OUT.
WINDS AND SEAS WILL DROP BELOW SMALL CRAFT LEVELS DURING THE
EVENING AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE GRADIENT
SHOULD RELAX ENOUGH SO THAT WINDS COULD DROP BELOW 10 KNOTS TOWARD
DAYBREAK THURSDAY.
A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON THURSDAY
NIGHT. AS A RESULT, WIND GUSTS OF 25 TO 30 KNOTS ARE POSSIBLE FROM
THURSDAY NIGHT INTO FRIDAY.
LOW PRESSURE APPROACHING FROM THE SOUTHWEST SHOULD PASS OVER OR
NEAR OUR REGION ON SATURDAY. THE SYSTEM SHOULD NOT BE STRONG
ENOUGH TO PRODUCE WIND GUSTS IN EXCESS OF 25 KNOTS. HOWEVER, A
PERSISTENT NORTHEASTERLY FLOW ASSOCIATED WITH THE LOW MAY CAUSE
WAVE HEIGHTS TO BUILD TO 5 TO 6 FEET OVER THE WEEKEND ON OUR OCEAN
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 7 AM EST THIS MORNING FOR PAZ054-055.
NJ...WIND ADVISORY UNTIL 7 AM EST THIS MORNING FOR NJZ001.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...IOVINO
AVIATION...IOVINO/HAYES
MARINE...IOVINO/HAYES
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
439 PM EST WED JAN 18 2012
.SYNOPSIS...
A PRESSURE RIDGE OVER THE FORECAST AREA TONIGHT WILL MOVE OFF THE
COAST THURSDAY. A COLD FRONT WILL MOVE INTO THE AREA FRIDAY AND
STALL.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SURFACE RIDGE SHOULD BE OVER THE FORECAST AREA TONIGHT. RUC MODEL
IS SHOWING A VORT MAX THAT MOVES ACROSS THE FORECAST AREA 05Z-06Z.
THIS MAY BRING SOME SCATTERED MID LEVEL CLOUDS TO THE REGION BUT
SKIES ARE EXPECTED TO CLEAR AGAIN BY 08Z. SO STRONG RADIATIONAL
COOLING BEFORE DAYBREAK THURSDAY. USED RADIATIVE COOLING LOW
TEMPERATURE RADIATIVE SCHEME WHICH GAVE CAE 29 AND AGS 28. SO
LOWERED LOW TEMPERATURES ONE DEGREE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
THE DRY AIR MASS SHOULD REMAIN IN CONTROL THURSDAY. THE NAM AND GFS
SHOW A WEAK COLD FRONT APPROACHING THURSDAY NIGHT WITH THE FRONT IN
THE FORECAST AREA FRIDAY. CONVERGENCE ASSOCIATED WITH THE FRONT AND
WARM ADVECTION SHOULD RESULT IN CONSIDERABLE CLOUDINESS FRIDAY. THE
MODELS KEEP THE MOISTURE SHALLOW AND LIFT WEAK SO THE RAIN CHANCE
APPEARS LOW. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FORECAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CONFIDENCE IS LOW DURING THE EXTENDED PERIOD. THE GFS ENSEMBLES
SHOW HIGH SPREAD. THE OPERATIONAL GFS DISPLAYS A COLD FRONT AND
ASSOCIATED MOISTURE APPROACHING THE FORECAST AREA SATURDAY WITH
THE FRONT IN THE AREA SATURDAY NIGHT. THE FRONT APPEARS TO LINGER
SUNDAY WITH DEEPER MOISTURE SHIFTING NORTHEASTWARD. ANOTHER FRONT
APPEARS TO MOVE INTO THE FORECAST AREA MONDAY NIGHT WITH BRIEF
DRYING MONDAY...AND YET ANOTHER SYSTEM APPROACHING WEDNESDAY.
TIMING UNCERTAINTY IS HIGH BECAUSE OF THE FAST LOW AMPLITUDE
UPPER-LEVEL FLOW DURING MUCH OF THE PERIOD. LEANED TOWARD THE GFS
ENSEMBLE MEANS AND CONTINUED THE FORECAST OF CHANCE POPS THROUGH
THE PERIOD. THE LOW AMPLITUDE FLOW SHOULD HELP BRING ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
HIGH CONFIDENCE FOR VFR THROUGH THE TAF PERIOD.
WITH THE INFLUX OF DRIER AIR...NO SIGNIFICANT FOG IS EXPECTED
TONIGHT. NORTHWEST TO NORTHEAST WINDS THIS AFTERNOON WILL
BECOME LIGHT AND VARIABLE OVERNIGHT...THEN SHIFT SOUTHEAST
THURSDAY AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE REGION.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIG/VSBY ARE POSSIBLE LATE
FRIDAY NIGHT INTO SUNDAY AS A COLD AFFECTS THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...07
NEAR TERM...07
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
710 PM EST THU JAN 19 2012
.AVIATION /00 UTC TAFS/...
PRIMARY FOCUS ON RAPIDLY DETERIORATION OF CIGS/VSBY MIDDAY WITH
ONSET OF SIG SNOWFALL. IN MEANTIME LAKE EFFECT CLOUDS SHOULD SUCCUMB
TO XTRMLY DRY UPSTREAM AIR ACRS WI...WHERE SFC DPS ARE IN NEG TEENS
F RANGE. DRY AIR ENTRAINMENT TO LIMIT ANY SHSN TO VERY LIGHT MULTI
BANDS FOR THIS EVENING. NEXT STORM SYSTEM ACRS INTMTN REGN TO
ADVANCE RAPIDLY OVERNIGHT AND DRIVE INTENSE MIDLVL
DEFORMATION/UPGLIDE ACRS NRN IN. ONCE TOP/DOWN SATURATION IS
COMPLETE EXPECT A PROLONGED PD OF IFR TEMPO LIFR MET CONDS AT BOTH
SITES WITH STRONG UVM COINCIDENT WITH DEEP /ABOUT 4KFT/ SATURATED
DENDRITIC GROWTH ZONE NOTED PER LATEST NAM BUFKIT.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
SIGNIFICANT SNOW ACCUMULATIONS FRIDAY/FRIDAY NIGHT WILL BE THE MAIN
CONCERN FOR THE SHORT TERM. A WINTER WEATHER ADVISORY WILL BE ISSUED
FOR LATE MORNING FRIDAY THROUGH FRIDAY NIGHT FOR APPROXIMATELY
NORTHERN TWO THIRDS OF THE FORECAST AREA.
ACCUMULATING LIGHT SNOW THIS AFTERNOON HAS SHIFTED WELL SOUTH OF
ROUTE 30 LATE THIS AFTERNOON...AND WILL CONTINUE TO SAG SOUTHWARD
THROUGH THE REMAINDER OF THE LATE AFTERNOON HOURS AS AXIS OF LOW
LEVEL FRONTOGENESIS PUSHES SOUTH OF THE FORECAST AREA. FURTHER TO
THE NORTH...LAKE EFFECT SNOW SHOWERS HAVE BEEN INCREASING IN
INTENSITY WITH FAIRLY STRONG 850 HPA/LAKE DELTA TEMPS ON THE ORDER
OF 20 TO 23 DEGREES. RUC SOUNDINGS SUGGEST A NEARLY ISOTHERMAL LAYER
FROM 850 TO 700 HPA WHICH IS LIMITING DEPTH OF THIS LAKE GENERATED
INSTABILITY WITH LAKE INDUCED EQUILIBRIUM HEIGHTS ON THE ORDER OF
ABOUT 5K FT. ANOTHER NEGATIVE FACTOR POINTING AGAINST SIGNIFICANT
LAKE EFFECT SNOW ACCUMULATIONS IS MUCH DRIER MID LEVEL AIR THAT WAS
WORKED INTO THE SOUTHERN GREAT LAKES REGION BEHIND THE SYSTEM WHICH
BROUGHT THE ACCUMULATING SNOW TODAY. THIS MARGINAL LAKE EFFECT SETUP
WILL CONTINUE FOR MUCH OF THE EVENING AND INTO THE OVERNIGHT...AND A
FEW LOCATIONS MAY PICK UP A HALF INCH TO AN INCH OF ADDITIONAL
ACCUMULATION BEFORE INVERSION HEIGHTS CRASH MORE SUBSTANTIALLY
DURING THE OVERNIGHT HOURS. AREAS AWAY FROM LAKE EFFECT
CLOUDS/PRECIP SHOULD CLEAR THIS EVENING. A WEAKENING GRADIENT WITH
SFC RIDGE AXIS BUILDING IN COMBINED WITH THIS CLEARING SHOULD
ALLOW FOR VERY COLD TEMPS TONIGHT INTO THE SINGLE DIGITS ABOVE
ZERO. SOME INCREASE IN HIGH CLOUDS IS EXPECTED LATE TONIGHT THAT
MAY LEVEL OUT TEMPERATURES AFTER 09Z.
ATTENTION WILL THEN TURN TO WHAT WILL BE A VERY FAST MOVING UPPER
LEVEL SYSTEM THAT IS APPROACHING THE PACIFIC NORTHWEST COAST AT THIS
TIME. LOW LEVEL WINDS WILL BACK SOUTHWESTERLY ON FRIDAY AHEAD OF
THIS TROUGH WHICH WILL SET UP A PERIOD OF INTENSE ISENTROPIC UPGLIDE
FRIDAY AFTERNOON/EARLY EVENING OVER THE SHALLOW RETREATING ARCTIC
AIR MASS. STRONG FRONTOGENETIC FORCING ALSO TO DEVELOP IN THE
850/700 LAYER AS THIS LOW LEVEL FLOW RAMPS UP. 12Z NAM REMAINS A
SLIGHTLY SLOWER AND FURTHER NORTH OUTLIER IN REGARDS TO THIS
SYSTEM...WITH 09Z SREF GENERALLY LENDING SUPPORT TO THE MORE RUN TO
RUN CONSISTENT GFS/ECMWF. GENERALLY UTILIZED A PREDOMINATELY
SREF/GFS/ECMWF BLEND FOR THIS FORECAST WITH A MUCH SMALLER
WEIGHTING TOWARD NAM. PERIOD OF MOST INTENSE SNOWFALL APPEARS TO
BE SHAPING UP IN THE 21Z-03Z TIMEFRAME WITH BEST COLOCATION OF
STRONGER SYNOPTIC LIFT WITH FAVORABLE DENDRITIC GROWTH ZONE.
MODEL QPF FROM 12Z SUITE OF MODELS STILL TEND TO SUPPORT MAINLY
HIGH END ADVISORY LEVEL SNOW ACCUMULATIONS WHEN CONSIDERING
EXPECTED SNOW TO LIQUID RATIOS ON THE ORDER OF 15:1 ACROSS THE
NORTH.
CONCERN WITH THESE TYPE OF INTENSE LOW/MID LEVEL BAROCLINIC ZONES IS
FOR AREAS OF ENHANCED BANDING WHICH COULD PUSH SOME AREAS INTO LOW
END WARNING ACCUMULATIONS. 12Z GFS MODEL CROSS SECTIONS STILL
INDICATE RELATIVELY HIGH STATIC STABILITY ATOP THIS LOW LEVEL
FRONTOGENESIS FORCING WHICH MAY TEND TO DISCOURAGE SMALLER SCALE
INTENSE BANDING...AND A BROADER RESPONSE IN UPWARD VERTICAL MOTION
FIELDS. SYSTEM ALSO WILL BE VERY PROGRESSIVE WITH SOME INDICATIONS
OF ISENTROPIC UPGLIDE WEAKENING SLIGHTLY FROM WEST TO EAST INTO
NORTHEAST INDIANA BY EVENING. TAKING THE ABOVE FACTORS INTO
CONSIDERATION HAVE OPTED TO GO WITH A HIGH END WINTER WEATHER
ADVISORY FOR SNOW ACCUMULATIONS OF 3 TO 7 INCHES NORTHERN TWO
THIRDS...WITH THE HIGHER ACCUMULATIONS EXPECTED FAR NORTHERN
INDIANA/SOUTHERN LOWER MICHIGAN. WINDS NOT EXPECTED TO BE AN OVERLY
HUGE CONCERN WITH THIS SYSTEM...BUT A BRIEF PERIOD IN THE 21Z-03Z
TIMEFRAME OF 1 TO 2 INCH PER HOUR SNOWFALL RATES APPEARS TO BE A
GOOD POSSIBILITY. IN TRENDING MORE TOWARD GFS...HAVE CONFINED MIXED
PRECIP MENTION TO A CHANCE OF SLEET ACROSS THE SOUTH BUT THIS WILL
NEED TO BE WATCHED IN FUTURE FORECASTS ONCE CONFIDENCE IN LOW LEVEL
THERMAL FIELDS INCREASES. SNOW WILL BEGIN TO WANE LATE FRIDAY NIGHT
WITH INDICATIONS OF FAR SOUTHEAST GETTING INTO SOME ENHANCED
SNOWFALL AS A PIECE OF EASTERN PACIFIC SHORT WAVE DIGS MORE
AGGRESSIVELY INTO THE OHIO RIVER VALLEY.
&&
.LONG TERM...
SUNDAY THROUGH THURSDAY
SIG PATTERN ADJUSTMENT TO OCCUR IN THE LONG TERM PERIOD AS REX BLOCK
RIDGING SHIFTS WEST OVER ALASKA...WITH SUBSTANTIAL UPPER LEVEL
TROUGHING EXPECTED THERE BY THIS WEEKEND. THIS WILL RESULT IN A
SWITCH BACK TO FAST WESTERLY GENERALLY MILD FLOW...WITH EMBEDDED
FAST MOVING IMPULSES PROVIDING PERIODIC CHANCES FOR RAIN/SNOW. THIS
WILL OCCUR AFTER THE ADVECTION OF A POTENT MID LATITUDE CYCLONE
EARLY NEXT WEEK...A SYSTEM WHICH COULD BRING A SUBSTANTIAL AMOUNT OF
RAIN/WIND/AND EVEN THUNDERSTORMS TO THE AREA SUNDAY NIGHT INTO
MONDAY MORNING. ECMWF/GFS/AND GEFS SOLUTIONS CONTINUE TO REMAIN
NEARLY PHASED PER HEIGHT SOLUTIONS IN THE PERIOD...WITH INCREASED
FORECAST CONFIDENCE IN THE PERIOD.
SAT-MON...FRIDAY SYSTEM WILL BE IN THE PROCESSES OF EXITING THE
REGION WITH A LOW CHANCE FOR LINGERING LIGHT SNOW FAR SE SAT AM.
WEAK SUBSIDENT REGIME WITH SFC RIDGING WILL SUPPORT GRADUAL EROSION
OF LINGERING LOW CLOUDS...WITH WINDS VEERING SE THROUGH THE SAT
PERIOD. MEANWHILE...A SIG MID LEVEL TROUGH IS EXPECTED TO DIG INTO
THE SW CONUS AND BEGIN TO EJECT TOWARD THE REGION. SYSTEM INFLUENCE
TO THE LOCAL AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY
FLOW INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC
ZONE IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE
EJECTING MID LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE
FALLS...SUPPORTING RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL
THETA-E ADV TO ENSUE SUNDAY IN THE REGION WITH SIG SFC LAYER
DEWPOINT RISES INTO SUNDAY NIGHT. STAUNCH LL FLOW WITH A 60 TO 70
KNOT LLJ PROGGED IN THE ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT
DEEP LAYER THETA-E RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A
SATURATED BL WITH DRIZZLE AND FOG EXPECTED TO DEVELOP SUNDAY
AFTERNOON INTO THE EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT.
ECMWF H7-H3 LAYER ANALYSIS REVEALS A RATHER IMPRESSIVE EML WITH
STEEP MID LEVEL LAPSE RATES GIVEN STRONG LOW CENTERED WAA. H85
THETA-E APPROACHES 325K BY LATE SUNDAY NIGHT...WITH SW INDICES
NEGATIVE...INDICATING A GOOD ENVIRONMENT FOR ELEVATED THUNDERSTORMS.
HAVE INTRODUCED A LOW CHANCE THUNDER AT THIS POINT. ALBEIT
SMALL...THERE IS A CONCERN FOR SEVERE WEATHER GIVEN INDICATED H5
JETLET IN EXCESS OF 90 KNOTS...WHICH WOULD BE CAPABLE QLCS JET
DRIVEN CELLS. PERHAPS THE BIGGEST CONCERN ATTM IS FOR INCREASED
FLOODING CONCERNS GIVEN FULL SNOWPACK MELT WITH THE POTENTIAL FOR
HEAVY RAIN. WILL HIGHLIGHT IN AN ESF. NEGATIVE TROUGH TILT INDICATED
IN FORECAST MODELS SUGGEST A NW TRACK ADJUSTMENT PER THE SFC
LOW...WITH A SLOWER SYSTEM ARRIVAL POSSIBLE...IN ADDITION TO WARMER
THERMAL FIELDS. HENCE DROPPED THE SNOW MENTION SUN NIGHT/TRIMMED
MONDAY SNOW MENTION/AND ADJUSTED TEMPS UP. CAA WILL DOMINATE MONDAY
WITH FALLING TEMPS IN THE DAYTIME PERIOD LIKELY. LINGERING LIGHT
SNOW SHOWERS WILL BE POSSIBLE MAINLY NW.
TUE-THUR...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED PERIOD AND HAVE RETAINED POPS THEN...OPTING TO
KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS.
OTHERWISE...ADJUSTED TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY
ONCE AGAIN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ FRIDAY TO 7
AM EST /6 AM CST/ SATURDAY FOR INZ003>009-012-014-016>018.
MI...WINTER WEATHER ADVISORY FROM 10 AM FRIDAY TO 7 AM EST SATURDAY
FOR MIZ077>081.
OH...WINTER WEATHER ADVISORY FROM 10 AM FRIDAY TO 7 AM EST SATURDAY
FOR OHZ001-002-004-005-015-016.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1056 AM MST WED JAN 18 2012
.UPDATE...
1007 AM MST WED JAN 18 2012
DUE TO THE PERSISTENT CLOUD COVER...HAVE LOWERED HIGH TEMPERATURES
FOR TODAY...KEEPING TEMPERATURES LOWER IN THE SNOW-COVERED AREAS.
HAVE ALSO LOWERED WIND SPEEDS AS THE CLOUDS SHOULD MAKE MIXING
MORE DIFFICULT.
CJS
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 222 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT.
JRM
&&
.AVIATION...
1056 AM MST WED JAN 18 2012
FOR THE 18Z TAFS...VFR CONDITIONS WILL PREVAIL THIS AFTERNOON AND EVENING
WITH RELATIVELY LIGHT WEST/SOUTHWEST WINDS. OVERNIGHT...THINGS BEGIN
TO CHANGE AS A BACKDOOR COLD FRONT PUSHES INTO THE AREA. AT KMCK...COLD
FRONT WILL MOVE THROUGH AROUND THE 09Z TIME FRAME BRINGING WITH IT A
SHIFT IN WIND DIRECTION TO THE NORTH/NORTHEAST AND LOW STRATUS. THERE
MAY BE A BRIEF PERIOD OF IFR CIGS HERE WITH INITIAL COLD FRONT PASSAGE
BUT SHOULD RISE TO LOW MVFR LEVELS AS COLD AIR LAYER DEEPENS. AT
KGLD...LOWER CONFIDENCE HERE AS COLD FRONT IS EXPECTED TO STALL NEAR
THE KGLD AREA. WILL LEAVE WIND DIRECTION VARIABLE DURING THE MORNING
HOURS TO ACCOUNT FOR UNCERTAINTY AND CONTINUE VFR CONDITIONS. IT SHOULD
BE NOTED HOWEVER THAT IFR CIGS WILL CERTAINLY BE A POSSIBILITY SHOULD
THE COLD FRONT PROGRESS SLIGHTLY FARTHER WEST THAN CURRENTLY EXPECTED.
FOR THIS I WILL INCLUDE A LOW FEW DECK FOR THE POTENTIAL FOR IFR CIGS
AND WILL LET NEXT SHIFT REASSESS FURTHER.
050
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1007 AM MST WED JAN 18 2012
.UPDATE...
1007 AM MST WED JAN 18 2012
DUE TO THE PERSISTENT CLOUD COVER...HAVE LOWERED HIGH TEMPERATURES
FOR TODAY...KEEPING TEMPERATURES LOWER IN THE SNOW-COVERED AREAS.
HAVE ALSO LOWERED WIND SPEEDS AS THE CLOUDS SHOULD MAKE MIXING
MORE DIFFICULT.
CJS
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 222 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT.
JRM
&&
.AVIATION...
428 AM MST WED JAN 18 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
BREEZY SOUTHWEST WINDS WILL DEVELOP BY LATE MORNING WITH GUSTS TO
AROUND 25KTS PERSISTING THROUGH THIS EVENING. A COLD FRONT WILL MOVE
THROUGH KMCK OVERNIGHT WITH WINDS VEERING TO NORTHEAST. /024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
454 AM MST WED JAN 18 2012
.UPDATE...
ISSUED AT 450 AM MST WED JAN 18 2012
MID-HIGH CLOUD DECK HAS DEVELOPED RAPIDLY OVER THE PAST 2 HOURS
AND HAS BECOME VERY WIDESPREAD ACROSS WESTERN CWA...AND WILL
LIKELY PERSIST THROUGH MUCH OF THE DAY. THIS MAY HOLD TEMPS BACK
SOME DURING THE DAY...BUT DIFFICULT TO REALLY GAGE WHAT KIND OF
IMPACT IT WILL HAVE UNTIL SUNRISE WHEN THE THICKNESS OF CLOUD
SHIELD CAN BE BETTER DETERMINED.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 222 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT.
JRM
&&
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 222 AM MST WED JAN 18 2012
SHALLOW COLD AIR DOME MAY HANG AROUND EARLY IN THE PERIOD
ESPECIALLY IN EASTERN PORTIONS OF THE AREA ON SATURDAY. MILDER
TEMPERATURES RETURN FOR SUNDAY AND MONDAY. NEXT COLD FRONT COMES
THROUGH MONDAY NIGHT. MODELS HAVE BACKED OFF ON SNOW CHANCES AND
MOST ARE NOW DRY. COLDEST DAY LOOKS TO BE TUESDAY WITH
TEMPERATURES NEAR NORMAL FOR LATE JANUARY...THEN WARMING UP TO
SLIGHTLY ABOVE NORMAL FOR WEDNESDAY.
024
&&
.AVIATION...
428 AM MST WED JAN 18 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
BREEZY SOUTHWEST WINDS WILL DEVELOP BY LATE MORNING WITH GUSTS TO
AROUND 25KTS PERSISTING THROUGH THIS EVENING. A COLD FRONT WILL MOVE
THROUGH KMCK OVERNIGHT WITH WINDS VEERING TO NORTHEAST. /024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
447 AM MST WED JAN 18 2012
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 444 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT.
JRM
&&
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 444 AM MST WED JAN 18 2012
SHALLOW COLD AIR DOME MAY HANG AROUND EARLY IN THE PERIOD
ESPECIALLY IN EASTERN PORTIONS OF THE AREA ON SATURDAY. MILDER
TEMPERATURES RETURN FOR SUNDAY AND MONDAY. NEXT COLD FRONT COMES
THROUGH MONDAY NIGHT. MODELS HAVE BACKED OFF ON SNOW CHANCES AND
MOST ARE NOW DRY. COLDEST DAY LOOKS TO BE TUESDAY WITH
TEMPERATURES NEAR NORMAL FOR LATE JANUARY...THEN WARMING UP TO
SLIGHTLY ABOVE NORMAL FOR WEDNESDAY.
024
&&
.AVIATION...
428 AM MST WED JAN 18 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
BREEZY SOUTHWEST WINDS WILL DEVELOP BY LATE MORNING WITH GUSTS TO
AROUND 25KTS PERSISTING THROUGH THIS EVENING. A COLD FRONT WILL MOVE
THROUGH KMCK OVERNIGHT WITH WINDS VEERING TO NORTHEAST. /024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
428 AM MST WED JAN 18 2012
.DISCUSSION...
219 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT. /JRM
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHALLOW COLD AIR DOME MAY
HANG AROUND EARLY IN THE PERIOD ESPECIALLY IN EASTERN PORTIONS OF
THE AREA ON SATURDAY. MILDER TEMPERATURES RETURN FOR SUNDAY AND
MONDAY. NEXT COLD FRONT COMES THROUGH MONDAY NIGHT. MODELS HAVE
BACKED OFF ON SNOW CHANCES AND MOST ARE NOW DRY. COLDEST DAY LOOKS
TO BE TUESDAY WITH TEMPERATURES NEAR NORMAL FOR LATE JANUARY...THEN
WARMING UP TO SLIGHTLY ABOVE NORMAL FOR WEDNESDAY. /024
&&
.AVIATION...
428 AM MST WED JAN 18 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
BREEZY SOUTHWEST WINDS WILL DEVELOP BY LATE MORNING WITH GUSTS TO
AROUND 25KTS PERSISTING THROUGH THIS EVENING. A COLD FRONT WILL MOVE
THROUGH KMCK OVERNIGHT WITH WINDS VEERING TO NORTHEAST. /024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 AM MST WED JAN 18 2012
.DISCUSSION...
219 AM MST WED JAN 18 2012
04Z WATER VAPOR IMAGERY INDICATED BROAD TROUGHING ACROSS MUCH OF THE
CENTRAL PLAINS...WITH RUC ANALYSIS INDICATING A 160KT JET STREAK
JUST OFF OF THE PAC NW COAST. 00Z RAOBS INDICATED A COLD...DRY AND
FOR THE MOST PART STABLE AIR MASS IN PLACE OVER THE REGION.
SOUNDINGS ALSO INDICATED A MUCH DEEPER COLD AIR MASS NOW IN PLACE
OVER THE AREA AS TEMPS ALOFT FELL IN EXCESS OF 15C AROUND H825 AT
DDC AND FELL 13C AT LBF AT H7. AT THE SFC...RIDGE WAS CENTERED OVER
SOUTHEAST KANSAS WITH A TROUGH OVER EASTERN WYOMING.
MAIN FORECAST CONCERNS THROUGH FRIDAY NIGHT WILL MAINLY BE
TEMPERATURES THROUGHOUT THE PERIOD AND WIND SPEEDS TODAY.
TODAY-TONIGHT...LEE TROUGH TROUGH WILL CONTINUE TO DEEPEN THROUGH
THE DAY AS WEAK RIDGING ALOFT OCCURS OVER THE AREA. WITH VERY STABLE
CONDITIONS AND LITTLE FORCING FOR ASCENT...EXPECT LITTLE MORE THAN
INCREASING HIGH CLOUDS THROUGH MUCH OF THE DAY. OVERNIGHT STRONG
COLD FRONT WILL BEGIN TO BACK INTO THE CWA BY 09Z. LOOKS LIKE A
PERIOD OF LOW STRATUS WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE
AREA. IF THE BOUNDARY LAYER WAS COMPLETELY SATURATED...COULD SEE A
THREAT FOR A BRIEF PERIOD OF FREEZING DRIZZLE FOLLOWED BY FLURRIES
AS COLD AIR DEEPENS...BUT GIVEN MOISTURE PROFILES WHERE THE FRONT
WILL ORIGINATE...AM DOUBTFUL THAT THINGS WOULD FULLY SATURATE. WILL
HAVE TO EXAMINE THE LATEST ENSEMBLE DATA BEFORE MAKING A FINAL
CALL...BUT CURRENT THINKING IS PROBABILITIES ARE TOO LOW TO MENTION
AT THIS TIME.
GUSTY SOUTHWESTERLY WINDS WILL DECREASE A BIT DURING THE MORNING
HOURS...BUT WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON
HOURS. VERY STRONG NORTHWEST WINDS EXPECTED ALOFT TODAY...BUT WITH
SFC FLOW BEING ABOUT 70 DEGREES DIFFERENT THAN WINDS ALOFT...WEAK
INVERSION EXPECTED TO KEEP DEEP MIXING AND SNOW COVER IN SOME AREAS
WILL INHIBIT MIXING THESE WINDS DOWN...BUT WILL HAVE TO KEEP A CLOSE
EYE ON THINGS DURING PEAK HEATING. WITH WINDS GUSTING TO AROUND 30
MPH AND HUMIDITIES FALLING TO AROUND 20 PERCENT FIRE DANGER WILL BE
HIGHER THAN THE PAST FEW DAYS...BUT WITH WEAK MOISTURE ADVECTION AND
SNOW MELT IN SOME AREAS DO NOT EXPECT LOW HUMIDITIES TO BECOME
WIDESPREAD.
THURSDAY-FRIDAY NIGHT...INITIAL CONCERN WILL FOR THURSDAY WILL BE HOW
FAR WEST BACK DOOR COLD FRONT MOVES AND HOW STRONG TEMPERATURE
GRADIENT ACROSS IT WILL BE. BY THURSDAY MORNING...COLD AIR WILL
DEEPEN ENOUGH THAT IF THERE IS ANY PRECIPITATION THREAT IT WOULD BE
FLURRIES...BUT RIGHT NOW THE MOST LIKELY SCENARIO IS FOR A STRATUS
DECK TO DEVELOP AS FRONT PASSES WITH LITTLE THREAT OF MEANINGFUL
PRECIPITATION. STRONG WARM AIR ADVECTION EXPECTED OVERNIGHT AS FRONT
RETREATS ACROSS THE AREA AND WHILE A FEW STATIC STABILITY PROFILES
SUGGEST ATMOSPHERE WILL DESTABILIZE SOME IN THIS PERIOD...WITH
EXPECTED FLOW PATTERN AM DOUBTFUL THAT ANY MEANINGFUL MOISTURE
RETURN WOULD OCCUR TO ALLOW ANY INSTABILITY TO BE REALIZED.
POTENTIAL VORTICITY FIELDS SUGGEST A COMPACT SHORT WAVE TROUGH WILL
SLIDE ACROSS THE AREA DURING THE DAY FRIDAY. WITH MID LEVELS LESS
STABLE THAN THE PAST FEW DAYS COULD SEE A DECENT RESPONSE...BUT
GIVEN THE OVERALL PATTERN AND AVAILABLE GUIDANCE...THINK DO NOT SEE
ANY REALLY GREAT SOURCES OF MOISTURE TO SUPPORT ANY PRECIPITATION.
WHILE TROUGH MAY NOT BRING A PRECIP THREAT...DOES LOOK LIKE THIS
SYSTEM WILL CAUSE COLD FRONT TO ONCE AGAIN BACK INTO THE AREA
OVERNIGHT BRINGING ANOTHER PERIOD OF LOW STRATUS AND POTENTIALLY A
LARGE GRADIENT IN TEMPERATURES.
FOR THURSDAY AND FRIDAY TEMPERATURES...EXPECT TEMPS TO RANGE FROM THE 50S
IN THE WEST TO THE 20S IN THE EAST AS SHALLOW ARCTIC FRONT BACKS
INTO THE AREA. AM FAIRLY CONFIDENT IN COLD TEMPS IN THE EAST...WITH
BIG QUESTION BEING HOW FAR WEST FRONT WILL GET BEFORE IT BEGINS TO
RETREAT. WITH DIV Q FIELDS SUGGESTING SOME AGEOSTROPHIC SUPPORT FOR
PUSHING THE FRONT WEST AND HAVE LEANED TOWARDS A MORE AGGRESSIVE
WESTERLY PUSH FOR THE TIME BEING. THIS FRONTAL ZONE MAY CONTINUE TO
CAUSE A FEW PROBLEMS ON FRIDAY AS LARGE DISCREPANCIES EXIST IN
OPERATIONAL GUIDANCE. WITH PV ANOMALY MOVING ACROSS...THINK THIS
WILL HELP DISPLACE COLD AIR TO THE EAST BUT GIVEN THE UNCERTAINTY
THINK HOLDING DOWN TEMPS IN THE EAST AND NORTHEAST REASONABLE AT
THIS POINT. /JRM
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHALLOW COLD AIR DOME MAY
HANG AROUND EARLY IN THE PERIOD ESPECIALLY IN EASTERN PORTIONS OF
THE AREA ON SATURDAY. MILDER TEMPERATURES RETURN FOR SUNDAY AND
MONDAY. NEXT COLD FRONT COMES THROUGH MONDAY NIGHT. MODELS HAVE
BACKED OFF ON SNOW CHANCES AND MOST ARE NOW DRY. COLDEST DAY LOOKS
TO BE TUESDAY WITH TEMPERATURES NEAR NORMAL FOR LATE JANUARY...THEN
WARMING UP TO SLIGHTLY ABOVE NORMAL FOR WEDNESDAY. /24
JRM
&&
.AVIATION...
1017 PM MST TUE JAN 17 2012
FOR THE 06Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
TIGHTER PRESSURE HAS DEVELOPED NEAR KGLD AS SURFACE HIGH MOVES TO
THE EAST AND LEE TROUGH STRENGTHENS. EXPECTED WINDS TO STAY GUSTY
THERE UNTIL NEAR 12Z. GRADIENT TIGHTENS UP AFTER SUNRISE AND WINDS
SHOULD BECOME GUSTY AGAIN UNTIL LATE IN THE DAY. WINDS WILL BECOME
VARIABLE LATE IN THE PERIOD AT KMCK AS A COLD FRONT BEGINS TO MOVE
INTO THE AREA.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
833 PM EST THU JAN 19 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE EAST THROUGH NEW ENGLAND AND THE GULF
OF MAINE OVERNIGHT. LOW PRESSURE WILL SHIFT INTO THE MARITIMES ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. HIGH PRESSURE
WILL SHIFT EAST FRIDAY NIGHT AS WEAK LOW PRESSURE APPROACHES NEW
ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS OUT TO SEA
SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE WILL BUILD IN FROM
THE NORTHWEST SATURDAY NIGHT AND SUNDAY. LOW PRESSURE LIFTING
NORTHEAST OUT OF THE NORTHERN GREAT LAKES WILL DRIVE A COLD FRONT
TOWARD NEW ENGLAND ON MONDAY. THE FRONT WILL CROSS THE AREA MONDAY
NIGHT WITH A TRAILING TROUGH OF LOW PRESSURE MOVING THROUGH THE
REGION ON TUESDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST
ON WEDNESDAY. LOW PRESSURE WILL PASS SOUTH OF NEW ENGLAND ON
THURSDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
0123Z UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW BANDS OF LIGHT SNOW SHOWERS
MOVING ONSHORE FROM THE GULF OF MAINE THIS EVENING. MUCH OF THIS
PRECIPITATION HAS BEEN VERY LIGHT IN NATURE. MEANWHILE...THE
TIMING OF THE STEADY SNOWFALL ENTERING THE FORECAST AREA IS IN
GOOD AGREEMENT WITH THE SHORT TERM FORECAST FROM THE LATEST HRRR
RUN.
WILL KEEP WINTER WEATHER ADVISORIES IN EFFECT FOR THE SOUTHEASTERN
PORTION OF OUR FORECAST AREA. MUCH OF THE PRECIPITATION ENTERING
THE FORECAST AREA REMAINS LIGHT...HOWEVER THERE SHOULD BE MODERATE
SNOWBANDS EMBEDDED WITHIN THIS PRECIPITATION FIELD AS NOTED
ENTERING THE CT/RI COASTLINE. WITH SURFACE WAVE ALREADY BEGINNING
TO FORM NEAR JFK AT 01Z...IN COMBINATION WITH A BRIEF PERIOD OF
ENHANCED VERITICAL MOTION (INCLUDING THE SNOW GROWTH
REGION)...EXPECT AREAS OF 3-6 INCHES SNOWFALLS SOUTHEASTERN ZONES.
HIGHEST SNOWFALL TOTALS SHOULD BE NEAR THE PENOBSCOT RIVER VALLEY.
PREV UPDATE...
ALSO...LATEST HRRR MODEL UPDATE HAS A GOOD HANDLE WITH OCEAN
EFFECT SNOW SHOWERS ENTERING ROCKINGHAM AND YORK COUNTIES THIS
HOUR. HAVE UPPED POPS QUITE A BIT FOR THIS AREA TO ACCOUNT FOR
THIS LOCAL PCPN. -SHSN WILL SPREAD NORTHWARD IN THE NEXT HOUR OR
TWO INTO THE PWM AND POSSIBLY THE NHZ AREAS.
HAVE UPDATED GRIDS TO INCREASE CLOUD COVER OVERNIGHT TO OVERCAST
CONDITIONS WITH ADVISORIES IN EFFECT. REST OF THE GRIDS WILL
REMAIN RELATIVELY UNCHANGED WITH ADVISORIES CONTINUING FOR THE ERN
HALF OF THE FORECAST AREA.
PREV DISC...
WEAK LOW PRESSURE APPROACHING FROM THE WEST WILL BRING A
BRIEF ROUND OF LIGHT TO MODERATE SNOW TO THE REGION OVERNIGHT. LOW
PRESSURE STILL FORECAST TO RE-DEVELOP OVER SOUTHERN NEW ENGLAND
AND MOVE INTO THE GULF OF MAINE BUT MODELS NOT AS STRONG WITH THIS
SYSTEM TODAY AND QPF FOR THE EVENT HAS DROPPED OFF SOMEWHAT.
EXPECT SNOW TO PUSH INTO THE CONNECTICUT VALLEY EARLY THIS EVENING
AND QUICKLY OVER-SPREAD THE REMAINDER OF THE FORECAST AREA THROUGH
MIDNIGHT. WILL STILL BE GOING WITH THE CURRENT ADVISORIES FOR
SOUTHERN AND COASTAL MAINE EXCLUDING YORK COUNTY FOR THE OVERNIGHT
HOURS. HAVE NOT CHANGED ACCUMULATIONS MUCH FROM YESTERDAY WITH 2
TO 4 INCHES OF ACCUMULATION EXPECTED ACROSS MUCH OF NEW HAMPSHIRE
AND EXTREME SOUTHWEST MAINE. REMAINDER OF SOUTHERN AND COASTAL
MAINE WILL SEE 3 TO 6 INCHES OF SNOWFALL THROUGH EARLY FRIDAY
MORNING. EXPECT SNOW TO QUICKLY END IN NEW HAMPSHIRE AND SOUTHWEST
MAINE BEFORE DAYBREAK ON FRIDAY. SHOULD BE A MUCH WARMER NIGHT
WITH TEMPS IN THE LOWER TO MID TEENS IN THE NORTH AND MID TEENS TO
LOWER 20S IN THE SOUTH.
&&
.SHORT TERM /FRIDAY NIGHT/...
HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRINGING CLEARING
SKIES AND MOSTLY SUNNY WEATHER TO MOST OF THE AREA ON FRIDAY.
SHOULD SEE MORNING CLOUDS CLEARING OUT OF THE MOUNTAINS AND FAR
EASTERN ZONES BY NOON. EXPECT TEMPS TO RANGE THROUGH THE TEENS IN
THE NORTH AND THROUGH THE 20S AND LOWER 30S IN THE SOUTH.
MID HIGH LEVEL CLOUDINESS WILL BE ON THE INCREASE FRIDAY NIGHT AS
WEAK OVER-RUNNING PATTERN SHIFTS INTO THE NORTHEAST AHEAD OF LOW
PRESSURE MOVING INTO THE MID ATLANTIC STATES. WILL INTRODUCE
LOW CHANCE POPS INTO SOUTHERN NEW HAMPSHIRE AFTER MIDNIGHT BUT
EXPECT LITTLE IF ANY ACCUMULATION THROUGH SATURDAY MORNING. LOW
TEMPS WILL RANGE FROM ZERO TO 10 BELOW IN THE NORTH AND 5 TO 15
ABOVE IN THE SOUTH.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MODELS TRACK WEAK SFC LOW OFF THE MID ATLANTIC COAST E AND OUT TO
SEA ON SATURDAY. THIS WILL PRODUCE -SN ACROSS THE FCST AREA WITH
LGT ACCUMULATIONS PSBL. HIGHEST CHC OF SN AND HIGHEST
ACCUMULATIONS OVER MORE SRN AREAS CLOSER TO THE LOW WITH LOWEST
CHC AND ACCUMULATION TO THE N. VERTICAL TEMP PROFILE CD ENOUGH TO
SUPPORT ALL SN FOR THIS EVENT.
THE LOW MOVES OUT TO SEA FAIRLY QUICKLY WITH -SN ENDING FROM W TO E
IN THE AFTERNOON. HIGH PRES FOLLOWS WITH FAIR WX SATURDAY NGT AND
SUNDAY. THE HIGH MOVES OUT TO THE E SUNDAY NGT AS THE UPR LVL
RIDGE CRESTS ALONG THE E COAST. A STRONG UPR LVL CUTOFF SYSTEM
OVER THE UPPER MID WEST CREATES A FAIRLY STRONG SFC LOW OVER THE
GREAT LAKES THAT WILL TRACK SLOWLY E WITH A TRAILING CD FNT
EXTENDING TO THE S. AHEAD OF THIS SYSTEM INCREASING S SW FLOW FROM
SFC TO H5 BRINGS IN MUCH WARMER AIR ALOFT AND EVENTUALLY TO THE
SFC AS PRCP EVENTUALLY MOVES IN LATE SUNDAY NGT AND MONDAY. MAY BE
SOME -SN OR MIXED SN AND ICE TO BEGIN WITH BUT GRADUALLY PRPC
CHANGES OVER TO RA FOR MONDAY AND MONDAY NGT THOUGH SOME -FZRA
STILL PSBL ACROSS THE NRN TIER OF ZONES WHERE IT WILL TAKE THE
LONGEST TO SCOUR OUT THE CD AIR AT THE SFC.
THE CD FNT MOVES THRU BY TUESDAY MORNING WITH COLDER AIR FOLLOWING
THE FNT AS TEMPS LIKELY TO FALL DURING THE DAY AFTER MILD PREDAWN
READINGS. A SECONDARY UPR LVL TROF MOVES THRU WHICH MAY PRODUCE A
FEW -SHSN BUT THE N/MT ZONES HAVE THE BEST CHC OF -SHSN DUE TO
DEVELOPING UPSLOPE FLOW IN THE CD AIR ADVECTION BEHIND THE FNT.
HIGH PRES BRINGS FAIR WX WEDNESDAY FOLLOWED BY A FAST MOVING SFC
LOW THAT WILL TRACK TO OUR S BRINGING THE CHC OF -SN WEDNESDAY NGT
AND THURSDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SATURDAY
THRU SATURDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST...
EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN
TEMPS.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...MVFR/IFR CEILINGS AND VSBY DEVELOPING THIS
EVENING...IMPROVING TO VFR ON FRIDAY. VFR FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...IFR PSBL WITH -SN SATURDAY.
IFR OR LIFR PSBL WITH MIXED PRCP DEVELOPING LATE SUNDAY NGT AND
CONTINUING THRU MONDAY.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY IN EFFECT THIS EVENING THROUGH FRIDAY.
LONG TERM /SATURDAY THROUGH MONDAY/...CONDITIONS BELOW SCA LEVELS
SATURDAY THRU SUNDAY NGT...THEN INCREASE TO SCA LEVELS OR PSBL
GALES MONDAY INTO MONDAY NGT IN STRENGTHEN S SW FLOW AHEAD OF THE
CD FNT. WINDS SHIFT TO THE W AS THE FNT MOVES OUT TO SEA AND CONT AT
SCA OR PSBL GALE LEVELS ON TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 11 AM EST FRIDAY FOR MEZ012>014-
019>022-024>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1214 AM EST WED JAN 18 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS NORTHERN MAINE WEDNESDAY MORNING.
HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY NIGHT THROUGH
THURSDAY...THEN MOVE EAST THURSDAY EVENING. ANOTHER DEVELOPING
AREA OF LOW PRESSURE FROM MID ATLANTIC STATES WILL MOVE TOWARD THE
GULF OF MAINE THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...DROPPED WINTER WEATHER ADVISORIES ACROSS INTERIOR
DOWNEAST AND CENTRAL MAINE. LEFT NORTHERN AREAS GOING FOR A WHILE
LONGER W/SNOW HANGING ON. STARTING TO SEE SOME CONVECTIVE SNOW
BURSTS ACROSS THE W AND NW AREAS AS COOLER MID LEVEL TEMPERATURES
START MOVING IN. TWEAKED TEMPERATURES DOWN MORE ACROSS THE NORTH
PER THE LATEST TRENDS AND HOW THE RUC IS NOW SHOWING THE WARM NOSE
FURTHER E AND S OF CAR-PQI.
.PREVIOUS DISCUSSION...
ALL WNTR WX ADVS CONTD FOR OUR FA. LGT SN AND SLEET AND PERHAPS A
LITTLE FZRA OVR INTERIOR DOWNEAST AND E CNTRL PTNS OF THE FA ERLY
AND MID EVE SHOULD TRANSITION TO RN LATE THIS EVE AND OVRNGT
BEFORE ENDING THERE. FURTHER N OVR N CNTRL AND NE PTNS OF THE
FA...MODEL CRITICAL THICKNESSES AND NOMOGRAMS SUGGEST MORE OF THE
PRECIPITATION FALLING AS SN BEFORE TRANSITIONING TO A BRIEF PD OF
SLEET AND FZRA LATE TNGT...AND EVEN ENDING AS RN AS LLVL WARM AIR
IS ABLE TO PUNCH UP AHEAD OF THE SFC LOW TRACKING NE ALG THE ST
LAWRENCE VLY. OVR THE FAR NW...PRECIP SHOULD BE MSLY ALL SN...WITH
PERHAPS A MIX OF SLEET AND FZRA BEFORE ENDING.
WITH MORE QPF AND MOST OF THE PRECIP FALLING AS SN OVR NW PTNS OF
THE FA...GREATEST SNFL WILL DEFINITELY FALL OVR THE NW WHERE 3TO 5
IN ARE XPCTD WITH LCL 6 IN AMOUNTS POSSIBLE. AMOUNTS DROP OFF
PROGRESSIVELY S AND E...WITH COASTAL AREAS EXPERIENCING LITTLE IF
ANY SN ACCUMULATION AND NO ICE...WITH PRECIP ONLY BRIEFLY MIXED
WITH SNOW OR SLEET AT THE ONSET. TEMPS TNGT WILL INITIALLY HOLD
STEADY THIS EVE...THEN RISE SIGNIFICANTLY LATE TNGT...TO ABV FZG
SPCLY OVR SRN AND ERN PTNS OF THE FA...INCLUDING ERN AROOSTOOK
COUNTY.
AFT THE LOW TRACKS N AND E OF THE FA WED TOWARD LABRADOR...LLVL
COLD ADVCN ACCOMPANIED BY BRISK WNW SFC WINDS WILL BE THE MAIN
ISSUE...WITH TYPICAL TRAILING SC CLD CVR AND SCT SN SHWRS OVR THE
N HLF OF THE FA. SOME CONCERN ABOUT WIND GUSTS POSSIBLY APCHG WIND
ADV CRITERIA WED AFTN WITH THE STRONGEST PTN OF THE BACK SIDE PRES
GRAD...SPCLY OVR HIER TRRN WRN PTNS OF THE FA. BREAKING FACTORS
PREVENTING WIND ADV WIND GUSTS HOWEVER INCLUDE HI SFC-BL STATIC
STABILITIES WITH ARCTIC AIR ADVCTG INTO THE FA ATTM...ALONG WITH
SC CLD CVR WHICH COULD PREVENT THE STRONGEST WINDS ALF FROM ARND
925 MB FROM REACHING THE SFC...XCPT HIER OPEN TRRN WHERE FEW
PEOPLE INHABIT. TEMPS WILL FALL CONTINUOUSLY FROM ERLY TO MID MORN
HI TEMPS TO THE TEENS N AND 20S S BY SUNSET. CANNOT RULE OUT THE
POSSIBILITY OF BLSN WITH THE STRONGER WINDS WED AFTN...BUT THIS
COULD BE LIMITED TO THE FAR NW WHERE TEMPS ARE NOT LIKELY TO GET
ABV FZG WED MORN...OTHERWISE OTHER AREAS GETTING SIG SNFL WILL
LIKELY SEE THE TOP LAYER GET SLUSHY...PREVENTING MUCH IN THE WAY
OF BLSN.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF THE STATE WEDNESDAY
NIGHT AS HIGH PRESSURE BUILDS EAST TOWARD THE REGION. EXPECT
MAINLY CLEAR SKIES WEDNESDAY NIGHT. WINDS SHOULD DROP OFF AFTER
MIDNIGHT WEDNESDAY ALLOWING FOR SOME DECENT RADIATIONAL COOLING BY
THURSDAY MORNING. EXPECT SUBZERO LOWS ACROSS THE NORTH AND ZERO TO
5 ABOVE DOWNEAST.
THURSDAY WILL BE A DRY DAY AS HIGH PRESSURE SLIDES EAST DURING
THURSDAY AFTERNOON. CLOUDS WILL BE ON THE INCREASE IN ADVANCE OF
THE NEXT SYSTEM APPROACHING FROM THE WEST. HIGHS ON THURSDAY WILL
BE 5 TO 10 ABOVE ACROSS THE NORTH AND 10 TO 20 ABOVE ACROSS MOST
OF DOWNEAST MAINE.
WEAK LOW PRESSURE WILL MOVE ACROSS QUEBEC THURSDAY NIGHT GIVING
WAY TO A WEAK SECONDARY LOW DEVELOPING ACROSS THE GULF OF MAINE BY
EARLY FRIDAY MORNING. THIS LOW IS THEN EXPECTED TO TRACK RAPIDLY
NORTHEAST ACROSS THE MARITIMES ON FRIDAY. CONSENSUS OF MODEL SOLUTIONS
LEAVES ENOUGH FORECAST CONFIDENCE TO GO WITH CATEGORICAL POPS LATE
THURSDAY NIGHT AND INTO FRIDAY. IT SHOULD BE COLD ENOUGH FOR ALL
SNOW WITH THIS SYSTEM. AT THE PRESENT TIME IT LOOKS LIKE MOST
AREAS WILL SEE LIGHT TO PERHAPS MODERATE SNOW ACCUMULATIONS...
ESPECIALLY ACROSS DOWNEAST MAINE...AS MOST OPERATIONAL MODELS
INDICATE THIS SYSTEM WILL BE RATHER PROGRESSIVE. IN ANY
EVENT...THE STEADIEST SNOW SHOULD TAPER TO SNOW SHOWERS BY FRIDAY
AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOW PRESSURE WILL BE PULLING AWAY FROM THE FORECAST AREA AT THE
START OF THE LONG TERM PERIOD. AS SUCH EXPECT SNOW TO BE WINDING
DOWN FRIDAY NIGHT WITH COLDER AIR STREAMING INTO THE REGION. HIGH
PRESSURE WILL BRIEFLY BUILD IN BEHIND THE LOW SATURDAY. THEN ANOTHER
LOW WILL MOVE BY TO OUR SOUTH BRINGING THE CHANCE FOR SNOW TO MAINLY
SOUTHERN MAINE SATURDAY NIGHT. ANOTHER HIGH FOLLOWS WITH DRY WEATHER
RETURNING BY SUNDAY AFTERNOON. THEREAFTER DISCREPANCIES BETWEEN THE
LONG TERM MODELS BEGINS TO GROW. ANOTHER LOW WILL AFFECT THE REGION
EARLY NEXT WEEK BUT THE ECMWF SAYS SUNDAY NIGHT INTO MONDAY MORNING
WHILE THE GFS INDICATES MONDAY INTO MONDAY NIGHT. HAVE GONE WITH
SLIGHT CHANCE OR LOW CHANCE POPS FOR NOW. BOTH MODELS INDICATE HIGH
PRESSURE RETURNS TUESDAY SO HAVE GONE DRY FOR THAT PERIOD. WITH
SEVERAL SYSTEMS PROGGED TO PASS THROUGH THE REGION TEMPERATURES WILL
BE FAIRLY UP AND DOWN. THEY SHOULD BE FAIRLY CLOSE TO NORMAL DURING
THE SNOWY PERIODS BUT COOLER CONDITIONS ARE EXPECTED WHEN THE REGION
IS UNDER HIGH PRESSURE.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: AWW FOR BIA/BGR DONE.
PREVIOUSLY...INITIALLY LOW VFR OR MVFR LATE THIS
AFTN...TRANSITIONING TO IFR ALL SITES THIS EVE WITH PRECIP WITH SN
OVR NRN SITES TRANSITIONING TO MIXED PRECIP LATE TO VERY LATE TNGT
AND MIXED PRECIP OVR DOWNEAST SITES TRANSITIONING TO SHWRS LATE
TNGT AS WARMER AIR MOVES NWRD. DOWNEAST SITES WILL TRANSITION
RAPIDLY TO VFR BY ERLY WED MORN WITH STRONG DOWNSLOPE WRLY WINDS
WITH NRN SITES TRANSITIONING TO MVFR WED MORN...WITH THOSE
CONDITIONS CONTG THRU THE REST OF THE DAY.
SHORT TERM: VFR CONDITIONS WILL PREVAIL WEDNESDAY NIGHT THROUGH
THURSDAY. MVFR/IFR CONDITIONS ARE THEN LIKELY LATER THURSDAY NIGHT
THROUGH FRIDAY MORNING...ESPECIALLY KBGR/KBHB TERMINALS IN SNOW.
VFR UNDER HIGH PRESSURE EXPECTED FRIDAY NIGHT AND SATURDAY WITH
PERHAPS SOME LINGERING IFR EARLY FRIDAY EVENING ACROSS THE FAR
NORTH DUE TO SNOW SHOWERS. LOW PRESSURE MOVING BY TO THE SOUTH OF
THE STATE WILL BRING THE POTENTIAL FOR MVFR OR EVEN SOME IFR IN
SNOW SHOWERS TO THE SOUTHERN TERMINALS SATURDAY NIGHT. HIGH
PRESSURE AND VFR RETURNS BY SUNDAY AFTERNOON.
&&
.MARINE...
NEAR TERM: WILL CONT THE GLW EARLIER ISSUED...BEGINNING LATE TNGT
WITH WSW WINDS AND CONTG THRU ALL OF THE DAY WED AS WINDS BECOME
WNW BEHIND DEPARTING DEEPENING LOW PRES. USED A BLEND OF NAM12 AND
GFS40 FOR WINDS AND KEPT CLOSE TO WW3 WV HTS FOR THIS UPDATE.
SHORT TERM: GALE FORCE WINDS ARE EXPECTED INTO EARLY WEDNESDAY
NIGHT WITH WINDS DIMINISHING TO SMALL CRAFT ADVISORY LEVELS BY
LATER WEDNESDAY NIGHT...AND THEN BELOW SMALL CRAFT ADVISORY LEVELS
BY EARLY THURSDAY MORNING. WINDS MAY THEN INCREASE TO NEAR GALE
FORCE BEHIND LOW PRESSURE ON FRIDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 8 AM EST THIS MORNING FOR
MEZ001>006-010.
MARINE...GALE WARNING UNTIL 9 PM EST THIS EVENING FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
424 PM EST WED JAN 18 2012
.SYNOPSIS...
HIGH PRESSURE, PASSING EAST, WILL PROVIDE A DRY BREAK TONIGHT
INTO MIDDAY THURSDAY. A COLD FRONT, COMING EAST FROM MINNESOTA, WILL
BRING SNOW SHOWERS THURSDAY AFTERNOON AND NIGHT. LOW PRESSURE,
COMING NORTHEAST FROM TEXAS, WILL PROVIDE A WINTRY MIX FRIDAY
NIGHT AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
PER BLEND OF RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED
WITH RECENT HRRR AND NAM MODEL OUTPUT, EXPECT ANY REMAINING
ISOLATED SNOW SHOWERS TO END EARLY THIS EVENING. CONDITIONS SHOULD
REMAIN DRY INTO MIDDAY THURSDAY.
FORECASTED LOW TEMPERATURES TO BE ABOUT 3 DEGREES COLDER THAN
NORMAL USING BLEND OF NAM AND GFS MOS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
BLEND OF RECENT SREF MODEL OUTPUT SHOWS LOW PRESSURE, COMING EAST
FROM MINNESOTA, WILL DRIVE A COLD FRONT THROUGH THE UPPER OHIO
VALLEY THURSDAY NIGHT. EXPECT TEMPERATURES TO REMAIN COLD ENOUGH
FOR THIS TO BE A SNOW EVENT. MORE RECENT MODEL MEMBERS, SUCH AS THE
NAM AND GFS, SHOW THE SNOW SHOWERS TO BEGIN AFFECTING MOST
LOCATIONS LATE IN THE AFTERNOON. THE BULK OF THE SNOW
ACCUMULATION, GENERALLY 1 TO 2 INCHES, WILL OCCUR THURSDAY
EVENING.
WITH THE UPPER LEVEL JET BACKING INTO A WESTSOUTHWEST ORIENTATION, RECENT
SREF MODEL OUTPUT THEN SHOWS LOW PRESSURE COMING NORTHEAST FROM
TEXAS. THE ASSOCIATED WARM AIR ADVECTION ALOFT WILL LIKELY CAUSE
MIXED PRECIPITATION ACROSS THE SOUTHERN TIER OF CWA FOR THIS
PERIOD. ONSET OF PRECIPITATION SATURDAY MORNING WILL CONSIST OF
RAIN...FREEZING RAIN...AND SLEET THROUGH SATURDAY AFTERNOON BEFORE
TURNING INTO RAIN AND SNOW IN THE EVENING. AREAS NEAR PITTSBURGH
AND NORTH WILL RECEIVE PRECIPITATION MOSTLY IN THE FORM OF SNOW.
SNOW ACCUMULATIONS AND POTENTIAL FOR ICING FROM FREEZING RAIN AND
SLEET MAY EVENTUALLY NECESSITATE WINTER WEATHER HEADLINES.
FORECASTED TEMPERATURES THIS PERIOD USING A BLEND OF NAM AND GFS.
THESE SHOWED TEMPERATURES TO BE NEAR NORMAL THURSDAY, GOING
COLDER THAN NORMAL FRIDAY, AND THEN REBOUNDING TO WARMER THAN
NORMAL VALUES SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SURFACE RIDGE WILL BUILD IN BEHIND A DEPARTING SYSTEM AND PROVIDE
DRY WEATHER LATE SATURDAY NIGHT INTO SUNDAY.
AN APPROACHING SHORTWAVE TROUGH WILL THEN PUSH A SURFACE LOW
ACROSS THE GREAT LAKES. PERIODS OF SHOWERS WILL ACCOMPANY THE
ASSOCIATED COLD FRONT MONDAY...WITH SCATTERED SHOWERS EXPECTED TO
CONTINUE INTO TUESDAY AS MOISTURE WRAPS BEHIND THE LOW.
DRIER CONDITIONS SHOULD RETURN BY WEDNESDAY AS A SURFACE HIGH
MOVES EASTWARD INTO THE OHIO VALLEY.
STAYED CLOSE TO HPC GUIDANCE WITH TEMPERATURES REMAINING WELL ABOVE
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
EXPECT STRATOCUMULUS CEILINGS TO BE REMAIN PREDOMINATELY IN THE VFR
RANGE THROUGH LATE AFTERNOON. BANDS OF SNOW SHOWERS IN NORTHWEST
FLOW WILL CAUSE BRIEF PERIODS OF MVFR RESTRICTIONS THROUGH 22Z.
BROKEN STRATOCUMULUS SHOULD SCATTER OUT BY EARLY EVENING AS LOW
LEVEL FLOW WEAKENS UNDER SURFACE HIGH PRESSURE.
NEXT LOW PRESSURE SYSTEM WILL CROSS THE GREAT LAKES ON THURSDAY AND
WILL SWING AN AREA OF LIGHT SNOW ACROSS THE UPPER OHIO VALLEY LATE
THURSDAY AFTERNOON INTO THURSDAY NIGHT. MVFR CONDITIONS WITH
OCCASIONAL IFR RESTRICTIONS CAN BE EXPECTED.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
VFR CONDITIONS WILL BRIEFLY RETURN BY FRIDAY AS A SURFACE HIGH
SLIDES ACROSS THE REGION. A SYSTEM TRACKING SOUTH OF THE AREA WILL
BRING RAIN AND SNOW SHOWERS WITH THE POTENTIAL FOR RESTRICTIONS
FRIDAY NIGHT AND SATURDAY. AFTER A PERIOD OF VFR WEATHER SATURDAY
NIGHT AND SUNDAY...AN APPROACHING FRONT IS PROGGED TO SPREAD
SCATTERED RAIN SHOWERS AND RESTRICTIONS ACROSS THE TERMINALS MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1106 AM EST WED JAN 18 2012
.SYNOPSIS...
COLD NORTHWEST WINDS WILL KEEP SCATTERED LIGHT SNOW SHOWERS ACROSS
THE UPPER OHIO VALLEY THIS AFTERNOON. HIGH PRESSURE WILL THEN PASS
BY TO PROVIDE A DRY BREAK TONIGHT INTO THURSDAY MORNING. A GREAT
LAKES LOW PRESSURE SYSTEM WILL BRING LIGHT SNOW SHOWERS THURSDAY
AFTERNOON AND EVENING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER BLEND OF RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED
WITH RECENT HRRR AND NAM MODEL OUTPUT, EXPECT BANDS OF SCATTERED
LIGHT SNOW SHOWERS TO CONTINUE ACROSS THE UPPER OHIO VALLEY INTO
MID AFTERNOON. ANY NEW SNOW ACCUMULATION WILL BE LIMITED AND
MAINLY ACROSS HIGHER ELEVATIONS.
THEN AS MIDWEST HIGH PRESSURE APPROACHES TOWARD EVENING, EXPECT
THE COLD WINDS ALOFT TO WEAKEN WHICH HELP STABILIZE THE SURFACE
LAYER AND END THE SNOW SHOWERS AND DECREASE THE CLOUD COVER.
TEMPERATURES WILL CHANGE LITTLE THROUGH THE AFTERNOON AS INDICATED
BY RECENT HRRR AND GFS LAMP VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DRY WEATHER IS FORECAST FOR TONIGHT AS HIGH PRESSURE IS PROJECTED
TO QUICKLY SLIDE ACRS THE REGION, AND A LOW DEVELOPS NORTH OF THE
GREAT LAKES. THE ADVANCE OF THAT SYSTEMS COLD FRONT SHOULD BRING
ANOTHER ROUND OF SNOW SHOWERS ON THURSDAY...AND LIKELY POPS WERE
INCLUDED FOR MUCH OF THE REGION...ALTHOUGH BETTER NUMBERS WERE
CONTINUED ALONG THE I 80 CORRIDOR. PROGRESSIVE NATURE OF THE
SYSTEM SHOULD LIMIT ACCUMULATION ONCE AGAIN, WITH ABOUT AN INCH
ANTICIPATED.
ANOTHER SHORTWAVE IS GFS/NAM TIMED FOR A FRIDAY APPROACH AND
SATURDAY PASSAGE. THAT SYSTEM AS CURRENTLY FORECAST COULD BRING
MORE SIGNIFICANT PRECIPITATION DESPITE ITS PROGRESSIVE NATURE. WIND
FIELDS/JET STRUCTURE...AND TEMPERATURE PROFILE WILL HAVE TO
MONITORED AS THAT SCENARIO MATURES.
SHORT TERM TEMPERATURES ARE FORECAST PRETTY CLOSE TO THE AVERAGES
WITH THE PROGRESSIVE PATTERN PROGGED OVR THE REGION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
ECMWF AND GFS MODELS ARE PROJECTING DEVELOPMENT OF AN UPR TROUGH OVR
THE MOUNTAIN/PLAINS STATES EARLY NEXT WEEK. FLOW OVR THE GREAT LAKES
AND UPR OH REGIONS SHOULD THEN BACK TO THE SOUTHWEST AND SUPPORT A
WARMER TEMPERATURE FORECAST. HOWEVER...A SERIES OF DISTURBANCES
WITHIN THAT FLOW IS EXPECTED TO SUPPORT PERIODIC SHOWERS.
MAGNITUDE OF THE TROUGH AND TIMING ARE QUESTIONABLE...THUS
CONFIDENCE IN SPECIFICS IS MINIMAL.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA, EXPECT STRATOCUMULUS CEILINGS
TO BE MAINLY IN THE VFR RANGE THIS AFTERNOON. SCATTERED BANDS OF
LIGHT SNOW SHOWERS CAN CAUSE BRIEF MVFR INTERLUDES THROUGH 20Z.
NORTHWEST WINDS CAN GUST TO 25 KTS.
EXPECT VFR TONIGHT AS STRATOCUMULUS DISSIPATES THIS EVENING. WINDS
WILL BECOME SOUTH 5 TO 8 KTS TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THERE CAN BE RESTRICTIONS LATE THURSDAY DUE TO COLD FRONTAL SNOW
SHOWERS. VFR CONDITIONS WILL PREVAIL ON FRIDAY AS A SURFACE HIGH
PASSES ACROSS THE TERMINALS. A SURFACE LOW PASSING SOUTH OF THE
AREA WILL RETURN THE CHANCE OF RAIN AND SNOW SHOWERS WITH
RESTRICTIONS ON SATURDAY AND SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
436 PM EST WED JAN 18 2012
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WEAK SHRTWV RDGING
IMPACTING THE UPR GRT LKS WITHIN LO AMPLITUDE TROFFING OVER CENTRAL
NAMERICA TO THE S OF CLOSED LO OVER HUDSON BAY. AS OF EARLY THIS
AFTN...THE SUBSIDENCE ASSOCIATED WITH THE SHRTWV RDG HAS ENDED PCPN
EVERYWHERE EXCEPT OVER THE N HALF OF THE KEWEENAW PENINSULA...WHERE
A LO PRES TROF LINGERS TO THE N OF SFC HI PRES IN THE OH RIVER
VALLEY. BUT AS THE FLOW CONTINUES TO BACK TO THE SW BTWN THE
DEPARTING HI TO THE SE AND ANOTHER SHRTWV MOVING E THRU THE NRN
PLAINS...THESE SHSN ARE TENDING TO DRIFT NEWD INTO LK SUP. THE
DISTURBANCE TO THE W IS A POTENT ONE WITH SUPPORTING H5/H3 JET MAX
AND WIND SPEEDS OF 100KT/150KT DIGGING ESEWD THRU THE NW PLAINS.
HOWEVER...SINCE UPSTREAM AIRMASS IS FAIRLY DRY...THE BULK OF THE
PCPN IS FALLING TO THE N OF WARM FNT AND ON THE COLD SIDE OF COLD
FNT ATTENDANT TO SFC LO IN WCNTRL MN. GUSTY NW WINDS UP TO 35-40KTS
ARE DRIVING VERY COLD AIR SEWD INTO THE NRN PLAINS BEHIND THIS LO
AND AHEAD OF VIGOROUS PRES RISE CENTER IN THE DAKOTAS. THE 12Z H85
TEMP AT GREAT FALLS MT WAS -31C.
&&
.SHORT TERM DISCUSSION /TNGT AND THU/...
TNGT...SHRTWV TO THE W IS FCST TO SLIDE ESEWD THRU NRN WI AND INTO
NRN LWR MI BY 12Z THU WHILE SFC LO CENTER SHIFTS ENEWD ACRS THE
KEWEENAW AND INTO ERN LK SUP BY 12Z THU. STRONG SLY FLOW OF H85
TEMPS ARND -12C OFF THE 4C WARM WATERS OF LK MI AHEAD OF THIS
FEATURE INDICATE THERE WL BE ENUF INSTABILITY TO GENERATE LES...
WITH SOME ENHANCEMENT AS DEEP LYR QVECTOR CNVGC/MSTR ASSOCIATED WITH
APRCHG SHRTWV ARRIVE OVHD. 12Z NAM/CNDN MODELS SHOW QPF OF 0.20-0.30
INCH NEAR ERY. CONSIDERING FVRBL OMEGA PROFILE WITHIN DGZ...EXPECT
HI SN/WATER RATIO ARND 25:1 AND UP TO 6 INCHES OF SN E OF ERY. THE
WINDOW OF OPPORTUNITY WL BE RATHER NARROW AS THE FLOW IS PROGGED TO
VEER MORE TO THE WSW OVERNGT...SHIFTING THE HEAVIER SHSN TO THE E.
ISSUED LES ADVY EARLIER TDAY FOR THIS EXPECTED SN. FARTHER
W...FAIRLY DRY ENVIRONMENT AHEAD OF THE COLD FNT AS OBSVD THIS AFTN
SUG THERE WL BE LTL IN THE WAY OF SN UNTIL THE COLD FROPA...ABOUT
03Z OVER THE FAR W AT IWD TO ARND 12Z AT ERY. WITH SHARP THERMAL
GRADIENT/FGEN...SUSPECT THERE WL BE A PERIOD OF SN WITH THE
FROPA...ESPECIALLY NEAR LK SUP WHERE THERE WL BE EXTRA
MOISTENING/UPSLOPE FLOW. OVER THE SCNTRL... EXPECT ONLY SCT -SHSN
WITH MORE DOWNSLOPE FLOW. ALTHOUGH THE SYNOPTIC SN WL CUT OFF
QUICKLY WITH FAST ARRIVAL OF DEEP LYR QVECTOR DVGC/SUBSIDENCE...LES
WL DVLP IN THE STRENGTHENING NW FLOW OF ARCTIC AIR LEFT IN THE WAKE
OF DEPARTING LO. H85 TEMPS ARE PROGGED TO PLUMMET TO ARND -25C AT
IWD BY 12Z THU. ANOTHER SGNFT FEATURE TNGT WL BE STRENGTHENING NW
FLOW ASSOCIATED WITH STRONG CAD/IN ADVANCE OF APRCHG PRES RISE
CENTER THAT IS FCST TO REACH THE W TOWARD 12Z. PREFER THE STRONGER
H925 WINDS UP TO 40-45KTS SHOWN BY THE 12Z GFS/LOCAL WRF-ARW RUNS
GIVEN THE STRENGTH OF THIS DISTURBANCE...AND THESE WINDS WL MIX
EFFICIENTLY TO THE SFC WITH VIGOROUS CAD. THE COMBINATION OF THE
STRONG WINDS AND FALLING TEMPS WL PUSH WIND CHILLS AS LO AS -20 TO
-25F OVER GOGEBIC COUNTY.
THU...GUSTY NW WINDS/VIGOROUS CAD WITH H85 TEMPS FALLING TO ARND
-25C AND STRONG SUBSIDENCE/DEEP LYR QVECTOR DVGC WL BE IN PLACE
BEHIND THE DEPARTING SFC LO/UPR DISTURBANCE AT DAYBREAK. EXPECT THE
WINDS TO DIMINISH THU AFTN FOLLOWING PASSAGE OF PRES RISE CENTER TO
THE E AFT 18Z. WITH THE SLOW APRCH OF HI PRES FM THE W...MODEL FCST
SDNGS SHOW THE INVRN BASE AT IWD SINKING TO AOB 3K FT AGL BY LATE IN
THE DAY AS WINDS BACK MORE TO THE W...DIMINISHING THE PCPN IN THAT
AREA. THIS FLOW WL REMAIN FAVORABLE FOR AREAS FARTHER TO THE N THRU
THE KEWEENAW...MAINTAINING HIER INVRN HGTS. EXPECT LES TO INTENSIFY
OVER THE E WITH ENHANCED LLVL CNVGC PERSISTING AT THE END OF LONG NW
FETCH OVER THE OPEN WATERS OF LK SUP. WITH INVRN BASE FCST ARND 5K
FT AGL OVER THE KEWEENAW AND OVER THE E...LES CHART SUGS UP TO 6
INCHES OF SN PER 12 HR PERIOD. ALTHOUGH THESE AMOUNTS MAY NOT EASILY
EXCEED WARNING THRESHOLDS...THE ARRIVAL OF MUCH COLDER AIR THAT
DROPS H85 TEMPS TO ARND -25C AND THE DGZ ALMOST TO THE SFC OVER THE
W AS WELL AS THE GUSTY WINDS WL HAMPER SN GROWTH...LEADING TO
SMALLER SN FLAKES. WITH GUSTY WINDS...EXPECT EFFICIENT REDUCTION IN
VSBY THAT JUSTIFIES GOING WITH WRNGS IN MOST COUNTIES EXCEPT FOR
GOGEBIC COUNTY...WHICH WL NOT BE AS EXPOSED TO THE STRONG WINDS.
WITH THE INFLUX OF COLD AIR...TEMPS WL BE STEADY OR SLOWLY FALLING
THRU THE DAY.
.LONG TERM /00Z FRI THROUGH NEXT WED/...
THURSDAY NIGHT INTO FRI...NW LES WILL BE ONGOING AT THE START OF THE
PERIOD...BUT INTENSITY SHOULD BE LIGHTER THAN THU MORNING AS DRY AIR
AND SUBSIDENCE ALOFT LOWERS INVERSION HEIGHTS TOWARDS 4-5KFT.
A SECONDARY SURGE OF LLVL MOISTURE WILL ARRIVE TOWARDS MIDNIGHT AS
MID LVL RIDGING SLIDES TO THE E OF THE AREA. THIS ADDITIONAL
MOISTURE BOOSTS THE INVERSION HEIGHTS TO 5-6KFT BY 06Z. AS THE HIGH
MOVES FARTHER SE AND A WEAK TROUGH SLIDES OVER NRN LAKE
SUPERIOR...LOW LEVEL FLOW WILL BECOME MORE FROM THE WSW. 850MB TEMPS
WILL WARM SOME TO AROUND -22C...WHICH PLACES MORE OF THE DGZ IN THE
BEST LIFT. THIS IS ALSO NOTED BY THE LAKE EFFECT SNOW PARAMETER
INCREASING TO AROUND 0.75 OVER THE KEWEENAW BY 03Z FRI. THE BACKING
WINDS WILL TEND TO FAVOR A STRONGER LES BAND FOCUSING SOMEWHERE OVER
NWRN UPPER MI FROM NEAR ONTONAGON INTO THE KEWEENAW...AND SHOULD
MOVE N THROUGH THE DAY AS WINDS BECOME MORE SWLY. LIKELY POPS FROM
THE PREVIOUS FORECAST LOOK GOOD...SO WILL MAKE MINOR TREAKS TO THOSE
GRIDS. ONGOING MULTI BANDED LES OVER ERN UPPER MI WILL MOVE OFFSHORE
BY 18Z FRI AS WINDS BECOME SWLY...BUT THERE MAY BE A PERIOD OF
STRONGER SNOW DUE TO CONVERGENCE AS WINDS BACK...BUT THAT MAY STAY
JUST OFFSHORE AS WELL.
WENT WITH THE LOW END OF GUIDANCE FOR TEMPS THU NIGHT. COLD...DRY
AIR AND DECREASING WINDS WILL BRING LOW TEMPS DOWN TO NEAR -20 OVER
THE INTERIOR WEST. WINDS WILL BE LIGHT AT AROUND 5KTS...BUT WIND
CHILLS WILL STILL FALL TO AROUND -30. CONTINUED TO HIGHLIGHT THIS
THREAT IN THE HWO. HIGHS WILL BE IN THE TEENS FRI.
AN UPPER SHORTWAVE MOVES TO OUR S FRI AFTERNOON...LEADING TO SOME
PRECIP SKIRTING THE SRN CWA. AT THIS TIME...THE MENOMINEE AREA LOOKS
TO GET THE MOST SNOW FROM THIS SYSTEM...BUT WOULD BE AN INCH AT
MOST. IF THE SYSTEM ENDS UP MOVING FARTHER N...SNOWFALL TOTALS WOULD
BE HIGHER.
SATURDAY...MODELS START TO DIVERGE ON SOLUTIONS AT THIS
POINT...ALTHOUGH NOT DRASTICALLY...YET. MAIN DIFFERENCES COME FROM
THE TIMING OF SFC RIDGING MOVING THROUGH. THE GFS IS ON THE SLOWER
END OF GUIDANCE...WITH THE RIDGE AXIS OF THE CWA AT 18Z SAT. THE
ECMWF IS FASTER...WITH THE AXIS OVER THE CWA AT 12Z SAT. THE BIG
DIFFERENCE FROM THIS IS WITH WIND DIRECTIONS. AHEAD OF THE RIDGE
AXIS...WINDS LOOK TO BE MORE NWLY...WHICH WOULD BRING SOME LIGHT LES
NEAR LAKE SUPERIOR E OF MUNISING. WILL GO WITH A MORE BLENDED
SOLUTION RIGHT NOW...WITH THE GREATEST POPS IN NW FLOW AREAS LATE
FRI NIGHT/SAT MORN. HIGHS WILL BE IN THE TEENS TO LOW 20S SAT.
SAT NIGHT THROUGH WED...A SERIES OF UPPER LEVEL DISTURBANCES
MOVES THROUGH DURING THIS TIME...BUT MODELS ARE HAVING A HARD TIME
HANDLING THESE SYSTEMS. NOT ONLY IS MODEL AGREEMENT POOR...RUN TO
RUN DISCONTINUITY IS ALSO A PROBLEM DURING THIS TIME. THESE FACTORS
LEAD TO WELL BELOW NORMAL CONFIDENCE IN THIS PART OF THE FORECAST.
OVERALL...STUCK WITH CONSENSUS MODEL BLENDS FOR THIS PERIOD.
THE GENERAL FEEL FROM THE MODELS IS THAT A LOW PRESSURE SYSTEM WILL
MOVE INTO THE NRN PLAINS SAT NIGHT INTO SUN. THIS LEADS TO
INCREASING TEMPS IN THE SW FLOW WAA REGIME AHEAD OF THE SYSTEM. THE
BEST CHANCE FOR PRECIP CURRENLTY LOOKS TO BE SAT NIGHT INTO
SUN...BUT AS STATED BEFORE CONFIDENCE IS LIMITED.
A PERIOD OF DRIER WEATHER WILL PROBABLY RESULT LATE MON OR TUE AS
UPPER LEVEL RIDGING MOVES OVER THE CWA. MODELS THEN SHOW A SHARP
UPPER TROUGH MOVING TO THE CENTRAL CONUS WED...WHICH WOULD RESULT IN
PRECIP OVER PARTS OF THE REGION.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
AS A HIGH PRESSURE RIDGE PASSES UPPER MI TODAY...CONDITIONS SHOULD
REMAIN AT VFR AT ALL SITES THROUGH THIS AFTERNOON. AN ARCTIC COLD
FRONT WILL SPREAD LIGHT SNOW FROM WEST TO EAST THIS EVENING...THOUGH
DRY AIR AHEAD OF THE FRONT SUGGESTS LIMITED VIS REDUCTION THROUGH
MID EVENING. LOW LEVEL JET AHEAD OF FRONT COMBINED WITH HIGH LOW
LEVEL LAPSE RATES SHOULD ALLOW FOR AN INCREASE IN WINDS NEAR THE
SURFACE INTO THIS EVENING...THOUGH SOME LLWS MAY DEVELOP IF ENOUGH
DECOUPLING OCCURS. BEHIND THE FRONT OVERNIGHT...NORTHWEST WINDS
INCREASE AT ALL THREE SITES...FAVORING MDT/HVY LES AT IWD AND CMX.
THE COMBINATION OF HEAVY LES AND STRONGER WINDS WILL SIGNIFICANTLY
REDUCE VIS AT CMX DURING THE OVERNIGHT HOURS. LES SHOULD BEGIN TO
EASE SLIGHTLY AROUND 18Z ON THURSDAY AS WINDS BEGIN TO BACK TO THE
WEST AND DRIER AIR MOVES INTO THE AREA.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GOING S GALES UP TO 35 KTS OVER ERN LK SUP THIS EVNG STILL APPEAR ON
TRACK WITH SHARPENING PRES GRADIENT/AREA OF PRES FALLS PASSING TO
THE N. AS THE SFC LO PASSES W-E LATE TNGT INTO THU...EXPECT SHARP
WSHFT TO THE NW. INFLUX OF BITTERLY COLD AIR WILL ENHANCE MIXING OF
WINDS UP TO 40-45 KTS JUST ABOVE THE SURFACE...GALES WILL DEVELOP IN
MOST AREAS. WITH HI WAVES AS WELL...EXPECT HEAVY FREEZING SPRAY OVER
THE ENTIRE LAKE. THE STRONGEST WINDS WILL TEND TO DIMINISH ON THU
AFTERNOON. HIGH PRESSURE WILL BRIEFLY MOVE THROUGH THURSDAY NIGHT
BEFORE A WEAK LOW PRESSURE SYSTEM MOVES OVER LAKE SUPERIOR ON FRIDAY.
HIGH PRESSURE WILL RETURN ON SATURDAY...THEN WILL MOVE EAST SATURDAY
NIGHT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS LOW PRESSURE
SYSTEM LOOKS TO MOVE INTO THE AREA SUNDAY NIGHT INTO MONDAY BEFORE
MOVING EAST MONDAY NIGHT. THERE IS STILL A LARGE AMOUNT OF
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR
MIZ084.
LAKE EFFECT SNOW WARNING FROM 7 AM THURSDAY TO 1 AM EST FRIDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW WARNING FROM 1 AM THURSDAY TO 7 AM EST FRIDAY
FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY FROM 9 PM THIS EVENING TO NOON CST
THURSDAY FOR MIZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ007.
LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 7 PM EST
THURSDAY FOR MIZ002.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 AM THURSDAY TO 7 AM EST
FRIDAY FOR LSZ243>251-264>267.
GALE WARNING UNTIL 7 PM EST THURSDAY FOR LSZ266-267.
GALE WARNING FROM 1 AM TO 7 PM EST THURSDAY FOR LSZ249>251-264-
265.
GALE WARNING FROM 7 AM TO 1 PM EST THURSDAY FOR LSZ242>245-248.
HEAVY FREEZING SPRAY WARNING FROM 1 AM EST /MIDNIGHT CST/
THURSDAY TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-240>242-
263.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 AM EST /6 AM CST/
THURSDAY FOR LSZ240-241.
GALE WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 1 PM EST
/NOON CST/ THURSDAY FOR LSZ162-263.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST THURSDAY FOR LMZ221-
248-250.
GALE WARNING UNTIL 1 PM EST THURSDAY FOR LMZ221-248-250.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TK
MARINE...KC/TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1217 AM EST WED JAN 18 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS... ISSUED AT 503 PM EST
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW STRONG UPR
DISTURBANCE IN THE MID MS RIVER VALLEY AND ACCOMPANYING SFC LO OVER
SRN LWR MI MOVING STEADILY TO THE E. ANOTHER DISTURBANCE IS A BIT
FARTHER N OVER MN. ALTHOUGH THE SHARPER DYNAMICS/WAD/MORE
SUBSTANTIAL MSTR ASSOCIATED WITH THE SOUTHERN DISTURBANCE IS
REMAINING TO THE S...ENHANCED H4-2 DVGC OVER THE CWA IN RRQ OF UPR
JET JUST S OF JAMES BAY AND THE UPR JET TO THE S THAT IS SUPPORTING
THE SOUTHERN SHRTWV AS WELL AS SLOPED FGEN ON THE COLD SIDE SYNOPTIC
FNT TO THE SE IS PROVIDING ENUF LIFT TO OVERCOME GENERAL CAD AT H85
TO BRING A WIDESRPEAD SN. THIS PCPN IS HEAVIEST IN THE N WIND SN
BELTS NEAR LK SUP WHERE THE INCOMING AIRMASS...H85 TEMPS AOB
-15C...IS CAUSING SOME ENHANCEMENT TO THE SN WITH UNIDIRECTIONAL N
WIND SHOWN ON THE MQT VWP THRU 8K FT MSL. SPOTTER NEAR IWD REPORTED
6-8 INCHES OF SN AS OF ABOUT 1630Z. HOWEVER...LATEST RADAR TRENDS
SHOW DIMINISHING MSTR/RETURNS ARRIVING W-E AS DISTURBANCES ARE
MOVING STEADILY E IN PROGRESSIVE UPR FLOW. UPSTREAM ARCTIC AIRMASS
IN MN IS QUITE DRY/STABLE PER 12Z INL RAOB...WHERE THE 12Z H85 TEMP
WAS -19C. SFC TEMPS ARE NOT MUCH ABV ZERO F IN THIS AREA...WITH
DEWPTS WELL BLO 0F.
&&
.SHORT TERM /TNGT AND WED/... ISSUED AT 503 PM EST
MAIN FCST CONCERNS ARE LES TRENDS/AMOUNTS AND GOING HEADLINES/NEED
TO MAKE ANY ADJUSTMENTS TO THESE.
TNGT...AS PAIR OF DISTURBANCES/UPR JETS SHIFT TO THE E...SHRTWV RDG
AXIS/DRIER AIR IS PROGGED TO FOLLOW INTO THE UPR LKS. LINGERING
SYNOPTIC PCPN SHOULD DIMINISH LATE THIS AFTN OVER THE E WITH THE
ARRIVAL OF THE DRYING ALF AND RECENT RADAR TRENDS. ALTHOUGH THE
INCOMING AIRMASS WL BE MORE THAN SUFFICIENTLY COLD FOR LES WITH H85
TEMPS FALLING TO ARND -20C...THE DRYNESS/STABILITY OF THE UPSTREAM
AIRMASS AS WELL THE STEADILY BACKING WINDS ACCOMPANYING THE MOVEMENT
OF SFC HI PRES INTO THE MID MS RIVER VALLEY BY 12Z WED WL TEND TO
LIMIT LES AMOUNTS. FCST SDNGS FOR IWD SHOW INVRN BASE SINKING TO 2K
FT AGL BY 12Z WITH A SW SFC WIND...SO LES SHOULD END ENTIRELY THERE
BY THAT TIME. LES WL BE MORE RESILIENT E OF MQT WITH LONGER FETCH...
MORE PERSISTENT LLVL CNVGC AND INVRN BASE HANGING CLOSER TO 5K FT
MOST OF THE NGT. WITH BACKING LLVL FLOW/ARRIVAL OF DRIER AIR...
EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR W HALF...WHERE SOME
CLRG IS LIKELY GIVEN DRYNESS OF UPSTREAM AIRMASS.
AS FOR HEADLINES...PLAN TO ALLOW THE GOING WRNGS/ADVYS FOR THE W TO
EXPIRE AS SCHEDULED AT 00Z. OPTED TO CANX BARAGA COUNTY WITH
UNFAVORABLE NNW FLOW...BUT EXTENDED THE MQT ADVY UNTIL 00Z TO
ACCOUNT FOR LINGERING SHSN TOWARD THE ALGER COUNTY LINE. WL LET THE
ALGER ADVY GO THRU THE NGT WITH BULK OF SHSN SHIFTING INTO THAT
AREA. CONSIDERED A HEADLINE FOR NRN SCHOOLCRAFT AND LUCE COUNTIES AS
WELL...BUT THESE AREAS MISSED OUT ON THE BULK OF THE SN TDAY. WITH
SHIFTING WINDS TNGT... SUSPECT SN TOTALS IN THIS AREA WL BE LESS
THAN THE 3-5" INDICATED BY LES CHART FOR EXPECTED CONDITIONS EVEN
THOUGH THERE MAY BE PERIODS WHERE LLVL CNVGC IS ENHANCED BY LAND
BREEZE FLOW OFF ONTARIO.
WED...NEXT SHRTWV IN PROGRESSIVE FLOW ALF IS FCST TO MOVE FM THE NRN
PLAINS TO MN BY LATE IN THE DAY...WITH DVPA/WAD/DEEP LYR QVECTOR
CNVGC ARRIVING OVER THE W IN THE AFTN IN INCRSG SLY FLOW. WITH THE
BACKING FLOW...ANY LINGERING LES OVER THE KEWEENAW AND E OF GRAND
MARAIS WL SHIFT BACK INTO LK SUP. SINCE THE LO/MID LVLS WL BE
DRY...INITIAL DYNAMICS WL RESULT IN MAINLY THICKER MID/HI CLDS. WL
RETAIN GOING POPS ONLY FOR THE FAR W. WITH THE RETURN SSW FLOW OFF
LK MI...THERE COULD BE SOME LK CLDS/SHSN THERE AS WELL. BUT AIRMASS
APPEARS TOO DRY OVERALL TO SUPPORT MORE THAN LO CHC POPS.
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN AGREEMENT WITH THE NEXT SFC LOW TO BE POSITIONED OVER
WESTERN LS AT 00Z THURSDAY TO RESIDE OVER CENTRAL LS/CENTRAL UPPER
MI BY 06Z...AND JUST EAST OF THE CWA BY 12Z THURSDAY. THERE ARE
SMALL DIFFERENCES WHICH SHOULD BE SMOOTHED OUT WITH ANOTHER RUN OR
2. THE 17/09Z SRF WAS THE SLOWEST/MOST NW OF THE OPTIONS WHILE THE
GFS WAS THE FARTHEST SOUTH. ALL SOLUTIONS WHERE STILL UNDER THE
RHELM OF POSSIBILITY.
THE SFC LOW WILL BE ASSISTED EASTWARD BY A 500MB TROUGH SWINGING
FROM MN AT 00Z THURSDAY...SLIDING EAST OF UPPER MI BY MID MORNING
THURSDAY. EVEN THROUGH HIGH PRESSURE WILL ATTEMPT TO BUILD IN FROM
THE DAKOTAS ON THURSDAY...A TYPICIAL LINGERING SFC TROUGH CAN BE
EXPECTED OVER LAKE SUPERIOR THROUGH AT LEAST FRIDAY MORNING. THE
TROUGH SHOULD DIMINISH IN STRENGTH FRIDAY...BUT WILL QUICKLY BE
REPLACED BY ANOTHER TROUGH OUT AHEAD OF THE NEXT LOW PUSHING
EASTWARD FROM THE DAKOTAS.
THE COLDEST TEMPERATURES WILL LIKELY BE THURSDAY NIGHT INTO FRIDAY
MORNING...PARTICULARLY INTERIOR WEST IF CLOUDS CLEAR OUT AS MUCH AS
EXPECTED.
DAYS 4 THROUGH 7...SATURDAY THROUGH TUESDAY
DISAGREEMENTS REMAIN WITH THE HANDLING OF THE FEATURE FOR THIS
WEEKEND. AT 500MB THE ECMWF IS APPROX 6 HOURS QUICKER THAN THE GFS
BY SUNDAY MONRNING. ADDING TO THE ISSUES THE CANADIAN IS NEARLY FLAT
WITH THE INCOMING THROUGH...WHILE THE ECMWF/GFS SHOW SIMILAR
STRENGTH. IN SUPPORT OF THE ECMWF...THE 17/00Z ENSEMBLE RUNS OF THE
GFS WERE GENERALLY QUICKER THAN THE OPERATIONAL GFS.
LOOK FOR A DOMINANT RIDGE TO DEVELOP OVER THE CENTRAL AND SOUTHERN
PLAINS LATE IN THE WEEKEND...AND BUILD ACROSS THE UPPER GREAT LAKES
MONDAY...BEFORE SHIFTING TO THE EAST MONDAY NIGHT INTO EARLY
TUESDAY. MORE SIGNIFICANT DIFFERENCES CREEP IN MODEL WISE FOR
DAY7/TUESDAY. THE ECMWF STRENGTHENS THE 500MB TROUGH OFF THE WEST
COAST SUNDAY INTO A SIZABLE CUT OFF LOW ACROSS AZ/NM MONDAY
AFTERNOON THROUGH TUESDAY. THE GFS IS MUCH MORE PROGRESSIVE. EITHER
WAY...THE NEXT 500MB TROUGH WILL LIKELY SLIDE IN DURING THE DAY
TUESDAY.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
GRADUAL BACKING OF WINDS FROM NW TO SW OVERNIGHT THRU THE MORNING
WILL BRING AN END TO LAKE EFFECT SNOW SHOWERS...AND MVFR CIGS WILL
CLEAR OUT. LINGERING MVFR GIGS SHOULD CLEAR OUT AT KIWD IN THE NEXT
HR OR TWO PER SATELLITE TRENDS. AT KSAW...LINGERING FLURRIES AND
MVFR CIGS SHOULD CLEAR OUT TOWARD 12Z. AT KCMX...OVERLAKE
TRAJECTORIES WILL MAINTAIN FREQUENT -SHSN THRU THE NIGHT WITH MVFR
VIS AT TIMES. WIND SHIFT TO THE S TOWARD MID MORNING MAY BRING A
PERIOD OF IFR VIS IN HEAVIER SNOW SHOWERS AS THE NORTHWARD MOVING
CONVERGENCE ZONE PASSES. VFR CONDITIONS ARE EXPECTED AT ALL SITES
THIS AFTN. ARCTIC FRONT WILL SURGE ACROSS THE UPPER GREAT LAKES
TONIGHT. AHEAD OF THE FRONT...40-50KT LOW-LEVEL JET WILL TRANSLATE
ACROSS THE AREA THIS AFTN/EVENING. AT THIS POINT...EXPECT ENOUGH
MIXING PER FCST SOUNDINGS TO MAINTAIN GUSTINESS AT THE SFC AND
PRECLUDE LLWS. WILL BE SOMETHING TO KEEP IN MIND. SOME -SN MAY BREAK
OUT AHEAD OF THE FRONT...BUT MUCH BIGGER STORY WILL BE STRONG WINDS
AND MDT/HVY LAKE EFFECT SHSN ALONG AND BEHIND FRONT LATE EVENING AND
THRU THE NIGHT. NW WINDS WILL FAVOR KIWD/KCMX FOR WORST
CONDITIONS...ESPECIALLY KCMX. SNOW/BLSN MAY RESULT IN CONDITIONS
FALLING BLO AIRPORT MINS AT KCMX AFTER MIDNIGHT TONIGHT.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT N WINDS UP TO 30 KTS EARLY THIS EVNG TO DIMINISH WITH
APPROACH OF HI PRES RIDGE FROM THE W. AS THIS HI CENTER SHIFTS TO
THE E WELL S OF THE UPPER LAKES...THE FLOW WILL ALSO BACK STEADILY
TO THE S ON WED AND INCREASE LATE IN THE DAY/EVNG AS ANOTHER LO PRES
CENTER MOVES TOWARD WESTERN LAKE SUP. ONCE THIS LO MOVES BY TO THE
E...A STRONG NW WIND WILL DRIVE BITTERLY COLD ARCTIC AIR OVER THE
AREA ON THU. THE MIXING ENHANCED BY THE CONSIDERABLE OVERWATER
INSTABILITY WILL DRAG STRONG NW WINDS TO THE SURFACE...SO MAINTAINED
GALE WATCH FOR WED NIGHT THRU THU. ALSO OPTED TO ISSUE HEAVY
FREEZING SPRAY WATCH FOR LATE WED NGT THRU THU NGT FOR ALL LK ZNS
WITH THE BITTERLY COLD AIR MOVING OVERHEAD. WINDS WILL DIMINISH AFT
THU NGT WITH WEAK PRES GRADIENT DOMINATING INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ006.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 AM THURSDAY TO 7 AM EST
FRIDAY FOR LSZ264>267.
GALE WARNING FROM 6 PM THIS EVENING TO 7 PM EST THURSDAY FOR
LSZ266-267.
HEAVY FREEZING SPRAY WARNING FROM 1 AM EST /MIDNIGHT CST/
THURSDAY TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-263.
GALE WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 1 PM EST
/NOON CST/ THURSDAY FOR LSZ162-263.
GALE WARNING FROM 1 AM TO 7 PM EST THURSDAY FOR LSZ264-265.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
545 PM CST THU JAN 19 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
/305 PM CST THU JAN 19 2012/
High momentum quasi-zonal flow will persist across the conus through
the weekend, becoming more amplified yet still in a progressive
state by Sunday. Shortwave trough and attendant rich Pacific
moisture source affecting the Pacific NW today will shear eastward
across the Rockies inducing weak lee cyclogenesis Friday with a
modified boundary layer return flow pulling into the mid Mississippi
River valley. The vast majority of elevated waa and top down
saturation via Pacific moisture should be relegated to the I-80
corridor and points north, though flurries/light snow could
potentially affect far northern/northeast Missouri as weak
uvv/isentropic ascent in the cold cloud bearing layer supportive for
ice crystal growth clip this region. Overall, would expect little if
any accumulation.
Will also need to watch trajectories of return flow from the south
and the potential for extensive low clouds and drizzle through a
largely part of the cwa. Am quite skeptical of model moisture
profile initializations this morning; and consequently this leads to
higher uncertainty regarding any saturation in the boundary layer
Friday morning. NAM-WRF is most aggressive with low clouds north of
a developing warm front, with other models only partially becoming
saturated. Feel central Missouri stands the best chance for low
clouds and possible some drizzle, yet sounding profiles are not
quite indicative of drizzle. Further west, more veered wind profiles
just below the H8 inversion layer suggest drier air precluding
saturation. Have hedged towards the drier solutions feeling modeled
soil/atmosphere interface is too cold and saturated versus reality.
Nevertheless, with or without low clouds, more extensive mid/high
clouds streaming over the Rockies should limit overall insolation,
and have kept forecast temps near a model blend around climatology,
or about a category lower than previously advertised.
Dry and cool high pressure will maintain its influence over the
region on Saturday insuring temperatures once again near or slightly
below the climatological average. Renewed stronger lee cyclogenesis
late Saturday afternoon will allow sfc winds to back around to a sly
direction, strengthening through the evening and overnight hours.
Thus, expect temperatures to actually begin to rise not long after
sunset Saturday into Sunday morning.
21
Sunday - Wednesday:
Models continue to struggle with the timing and intensity of a
system for the early part of next week. However there has been
increased consistency for a few runs in bringing the system into the
area Sunday into Monday. Both the ECMWF and the GFS show a rather
strong wave moving through the Central Plains Sunday and this has
some support from the GFS ensemble mean and the ECMWF ensemble mean.
The GEM looks to be a bit too fast compared to the other models but
also moves a wave through the area Sunday. The placement of the wave
from the current suite of models brings the main energy associated
with the system a bit further north but again there is agreement
amongst the deterministic models and their ensemble partners. With
the placement possibly a bit further north and with the wave
currently looking rather robust, have increased temperatures for
Sunday. There is the potential to see temperatures in the 60s for at
least southern zones but if trends continue we could see more
widespread 60+ degree readings. In fact, if this were springtime and
not mid January the warm sector dynamics would be fairly conducive
for severe weather. Fortunately it is still January and it should
just lead to a warm and windy day with perhaps a few showers during
the afternoon before the system lifts away and temperatures begin to
drop on the backside of the low. Models produce a well pronounced
deformation area which for now would affect mainly northern Kansas
through Nebraska and Iowa. Some wrap around precipitation is likely
though, given current forecast track and as cold air advects into
the region, in the wake of the departing low, a transition to some
light snow is expected. This should mainly impact northern Missouri.
Models show another wave entering the region Wednesday into Thursday
but the GFS seems too intense with its QPF given that the wave tries
to split into a northern stream wave and southwestern closed low.
Given this have eased up on POPs for the middle of the week which
were fairly heavily influenced by the going forecast and the and GFS.
CDB
&&
.AVIATION...
For the 00z TAF...Will maintain VFR forecast with east-northeast
winds veering to the east-southeast by Friday morning. Confidence
remains low on MVFR cigs developing overnight. NAM and to a lesser
extent the GFS have been forecasting MVFR clouds since at least the
12z Wednesday run. Inspection of 12z Thursday TOP sounding revealed
that this moisture was real. However, it appears the subsidence was
strong enough within this layer to prevent clouds from forming.
Overall, the latest RUC forecast sounding is doing best on cloud
forecast but it does hint at MVFR cloud cover forming after 09z
Friday. Will monitor the situation later tonight as warm air
advection processes may indeed result in MVFR cigs forming.
Since confidence remains low will leave out for now.
Otherwise, a second cold front is expected to drive through the
terminals by mid Friday afternoon with only a change in wind
direction.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1237 PM CST WED JAN 18 2012
.AVIATION...
ARCTIC FRONT WILL PUSH SOUTH LATER TODAY AND TONIGHT. WINDS WILL
SWITCH FROM GUSTY WEST TO NORTHWEST THEN NORTH. TEMPS WILL ALSO
PLUMMET...WELL BELOW FREEZING. FRONT WILL PUSH THROUGH KVTN
FIRST...AROUND 20Z...WITH THE BITTER COLD AIR ARRIVING AFTER 00Z.
ARRIVAL AT KLBF NOT AS WELL AGREED UPON IN THE MODELS...WITH A
TIME ESTIMATE AND MODEL CONCENSUS AROUND 01Z. BEHIND FRONT FRONT
WILL BE THE POTENTIAL FOR SOME MVFR CIGS. HIGHER CONFIDENCE IMPACT
FOR KVTN AND NORTH CENTRAL NEBRASKA...WHERE LIGHT SNOW IS ALSO
LIKELY OVERNIGHT. FURTHER SOUTH...FOR KLBF...CIGS STILL LOOK
PROBABLE...HOWEVER LIMITED LIFT RESULTING IN DRY CONDITIONS.
CIGS ARE EXPECTED TO SLOWLY LIFT LATE TOMORROW MORNING OR EARLY
AFTERNOON...LIKELY STILL MVFR BY 18Z.
&&
.PREV DISCUSSION... /ISSUED 536 AM CST WED JAN 18 2012/
UPDATE...
AVIATION...
VFR IS EXPECTED THROUGH 00Z. THEREAFTER AN ARCTIC FRONT WILL BEGIN
MOVING SOUTH THROUGH NRN NEB PRODUCING MVFR AND POSSIBLY IFR CIGS.
NOTE THAT THERE IS TIMING UNCERTAINTIES WITH THE ARRIVAL OF THE
MVFR AND IT COULD BEGIN AS EARLY AS 21Z BASED ON THE RUC MODEL.
THE FRONT AND ASSOCIATED FLIGHT RESTRICTIONS SHOULD DROP AS FAR
SOUTH AS KOGA AND KIML BY 12Z THURSDAY. LIGHT SNOW IS POSSIBLE AS
THE FRONT MOVES SOUTH.
WINDS TODAY ARE EXPECTED TO INCREASE TO 27030G40KT ACROSS THE
SANDHILLS...MAINLY THE WRN SANDHILLS WITH LESSER SPEEDS EAST THROUGH
KTIF AND KBBW.
PREV DISCUSSION... /ISSUED 417 AM CST WED JAN 18 2012/
UPDATE...
SHORT TERM...
BEST GUESS ON THE WIND SPEEDS TODAY AS DISCUSSED BELOW SUGGESTED
ADDING A FEW COUNTIES TO THE WIND ADVISORY.
PREV DISCUSSION... /ISSUED 344 AM CST WED JAN 18 2012/
DISCUSSION...
FORECAST CONCERNS IN THE SHORT TERM DEAL WITH ADVISORY CRITERIA WIND
SPEEDS ACROSS OUR WESTERN ZONES TODAY...AND TEMPERATURE FORECAST
THROUGH THE END OF THE WORK WEEK. ALSO OF IMPORTANCE WILL BE THE
POSSIBILITY OF FLURRIES LATE TONIGHT...AND THE CHANCE OF LIGHT SNOW
AND/OR FREEZING DRIZZLE EARLY FRIDAY MORNING.
WIND ADVISORY CONDITIONS ARE EXPECTED ACROSS PARTS OF WRN NEB TODAY.
THESE WEST WINDS ARE DEVELOPING AHEAD OF AN ARCTIC FRONT. A BLEND OF
500M AGL WINDS FROM THE NAM AND MAV AND MET GUIDANCE WERE USED FOR
SPEEDS. MOSGUIDE AND NAMDNG WAS USED FOR GUSTS WHICH SHOULD REACH
40KT ACROSS PARTS OF WRN NEB.
WARM AIR ADVECTION AND WESTERLY DOWNSLOPING WINDS WILL HELP PUSH
TEMPERATURES BACK NEAR IF NOT ABOVE SEASONAL AVERAGE THIS AFTERNOON
FOR MUCH OF THE CWA. THE EXCEPTION WILL BE THE NORTHERN REACHES OF
THE FORECAST AREA WHERE THE ABOVE MENTIONED COLD FRONT WILL DROP
SOUTH FROM THE DAKOTAS BRINGING ANOTHER ARCTIC PUSH OF COLD AIR.
LOOKING AT A WIDE RANGE OF HIGHS ONCE AGAIN ACROSS THE FORECAST
AREA...WITH THE WARMEST READINGS OVER SOUTHWEST NEBRASKA /READINGS
IN THE MID TO UPPER 40S/. OVER NORTHERN NEBRASKA...HIGHS WILL BE
REACHED EARLY IN THE DAY...AS CAA WILL TAKE HOLD AFTER THE NOON
HOUR...SO LOOKING FOR HIGHS ONLY IN THE 30S ALONG THE NIOBRARA RIVER
VALLEY.
FOR TONIGHT...CONTINUED THE MENTION OF FLURRIES ACROSS THE SAND
HILLS REGION OF NEBRASKA AS A SHORTWAVE RAPIDLY ADVANCES SOUTHEAST
FROM WESTERN CANADA TOWARD THE GREAT LAKES REGION. ALSO WENT AHEAD
AND INTRODUCED SLIGHT CHANCE POPS ACROSS NORTHERN NEBRASKA. WHILE THE
MODELS ARE STILL STRUGGLING ON THE TIMING OF THE PASSING BAROCLINIC
ZONE...THE NAM...GFS AND A LESSER EXTENT THE EURO DEVELOP QPF
OVERNIGHT TONIGHT. FLURRIES SEEM THE OPERATIVE MODE...HOWEVER
DECENT ISENTROPIC LIFT IN THE BAROCLINIC ZONE ALONG THE 285-295K
LAYERS INDICATE THE POTENTIAL FOR ACCUMULATION. A QUICK CHECK OF
PWATS INDICATE VALUES REACHING THE 75 PERCENTILE...SO
MOISTURE WILL BE AVAILABLE. POSSIBLE ACCUMULATIONS OF A QUARTER
TO A HALF INCH IS NOT OUT OF THE QUESTION LATE TONIGHT INTO TOMORROW
MORNING ALONG THE SOUTH DAKOTA BORDER...ESPECIALLY SINCE THE FALLING
SNOW WILL BE FLUFFY IN NATURE. ON TO OVERNIGHT LOWS TONIGHT...THE
GFS IS THE MOST PROGRESSIVE WITH THE COLD AIR DUMP...FOLLOWED BY THE
NAM AND EURO. THE MODELS SEEM TO CENTER ON THE AIRMASS REACHING -17C
AT 850MB BY 12Z THURSDAY OVER OUR NORTHERN ZONES. WITH THESE
READINGS...WOULDN/T BE SURPRISED TO SEE SUB ZERO READING ACROSS
NORTHERN NEBRASKA...UNLESS CLOUD COVER MODERATES TEMPERATURES. MAV
AND MET GUIDANCE INDICATES MINUS 9 AND 7 RESPECTIVELY AT VTN...WON/T
VENTURE THAT LOW YET...BUT ANY CLEARING WOULD ALLOW FOR THESE
READINGS...IF NOT COLDER. FURTHER SOUTH...SINGLE DIGIT READINGS
SEEM PLAUSIBLE...WITH THE EXCEPTION OF FAR SOUTHWEST NEBRASKA. WITH
THE HIGHER TERRAIN...THE COLD AIR IS STRUGGLING TO PUSH ANY FURTHER
WEST THAN THE COLORADO BORDER...SO MID TEENS WILL BE QUITE POSSIBLE
ACROSS THE SOUTHWESTERN ZONES EARLY TOMORROW. INTO THURSDAY
AFTERNOON...ARCTIC HIGH PRESSURE BUILDS EAST WITH RETURN SOUTHERLY
FLOW PUMPING H85 TEMPERATURES ABOVE 0C ACROSS THE SOUTHWEST. THIS
SETS THE STAGE FOR A WIDE RANGE OF HIGH TEMPERATURES OVER THE CWA.
LOOKING FOR HIGHS TO RETURN TO NEAR CLIMO OVER WESTERN AND SOUTHWEST
NEBRASKA...BUT REMAIN IN THE MID TEENS ACROSS NORTH CENTRAL
NEBRASKA.
FORECAST GETS INTERESTING THURSDAY NIGHT INTO FRIDAY...AS WARM AIR
ALOFT AND INCREASING MOISTURE COMBINE WITH A FRONTOGENETIC SUPPORT
TO PRODUCE LIGHT QPF OVER MUCH OF THE FORECAST AREA. THE
PREVIOUS FORECAST HAD INTRODUCED A SLIGHT CHANCE OF SNOW INTO THE
FORECAST...WILL CONTINUE...BUT ALSO INTRODUCE THE MENTION OF
FREEZING DRIZZLE. BUFR SOUNDINGS INDICATE TEMPERATURES ALOFT RISING
ABOVE 0C...WITH A SATURATED PROFILE INDICATIVE OF PERIODS OF FREEZING
RAIN. INTRODUCING FREEZING DRIZZLE IS A GOOD START...AND THEN CAN
GO FROM THERE...ESPECIALLY SINCE THESE SOUNDINGS INDICATE PERIODS OF
DRIER AIR IN THE MID LEVELS...MESSING WITH THE SEEDER FEEDER
PROCESSES.
LONG TERM...LOW CONFIDENCE IN THE EXTENDED AS THE MODELS ARE
STRUGGLING GREATLY ON RUN TO RUN CONSISTENCY AND GENERAL AGREEMENT.
IN FACT...ON FRIDAY THERE IS A GREATER THAN 15C DIFFERENCE IN H85
TEMPERATURES OVER PARTS OF THE CWA WHEN COMPARING THE GFS AND NAM.
WITH THE LACK OF AGREEMENT...GENERALLY SIDED WITH THE COLDER GFS
SOLUTION...WHICH WOULD SUGGEST BELOW AVERAGE HIGHS ON FRIDAY...WITH
THE EXCEPTION OF THE HIGHER TERRAIN OF SOUTHWEST AND WESTERN
NEBRASKA. FOR SATURDAY AND THE REST OF THE WEEKEND...MODELS
ACTUALLY DO AGREE ON WARMING TEMPERATURES...THUS TRENDED HIGHS BACK
INTO THE 40S AND 50S BOTH DAYS. BEYOND SUNDAY...SIGNIFICANT
DIFFERENCES BETWEEN THE THE LONGER RANGE MODELS WILL KEEP THE
FORECAST AS STATUS QUO...WITH ONLY SLIGHT CHANCE POPS GOING ACROSS
THE NORTH ON SUNDAY. OTHERWISE WILL KEEP THE EXTENDED DRY...WITH
NEAR SEASONAL TEMPERATURES UNTIL BETTER AGREEMENT IS DISPLAYED FROM
THE SOLUTIONS.
AVIATION...
VFR IS EXPECTED THROUGH 00Z. THEREAFTER AN ARCTIC FRONT WILL BEGIN
MOVING SOUTH THROUGH NRN NEB PRODUCING MVFR AND POSSIBLY IFR CIGS.
THE FRONT AND ASSOCIATED FLIGHT RESTRICTIONS COULD DROP AS FAR SOUTH
AS KOGA AND KLBF BY 12Z THURSDAY. ISOLATED FLURRIES ARE EXPECTED TO
ACCOMPANY THE FRONT AS IT MOVES SOUTH.
WINDS TODAY ARE EXPECTED TO INCREASE TO 27030G40KT ACROSS THE
SANDHILLS...MAINLY THE WRN SANDHILLS WITH LESSER SPEEDS EAST THROUGH
KTIF AND KBBW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR NEZ004-022-023-
035-056-057.
&&
$$
SHORT TERM/EXTENDED...99
AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
536 AM CST WED JAN 18 2012
.UPDATE...
.AVIATION...
VFR IS EXPECTED THROUGH 00Z. THEREAFTER AN ARCTIC FRONT WILL BEGIN
MOVING SOUTH THROUGH NRN NEB PRODUCING MVFR AND POSSIBLY IFR CIGS.
NOTE THAT THERE IS TIMING UNCERTAINTIES WITH THE ARRIVAL OF THE
MVFR AND IT COULD BEGIN AS EARLY AS 21Z BASED ON THE RUC MODEL.
THE FRONT AND ASSOCIATED FLIGHT RESTRICTIONS SHOULD DROP AS FAR
SOUTH AS KOGA AND KIML BY 12Z THURSDAY. LIGHT SNOW IS POSSIBLE AS
THE FRONT MOVES SOUTH.
WINDS TODAY ARE EXPECTED TO INCREASE TO 27030G40KT ACROSS THE
SANDHILLS...MAINLY THE WRN SANDHILLS WITH LESSER SPEEDS EAST THROUGH
KTIF AND KBBW.
&&
.PREV DISCUSSION... /ISSUED 417 AM CST WED JAN 18 2012/
UPDATE...
SHORT TERM...
BEST GUESS ON THE WIND SPEEDS TODAY AS DISCUSSED BELOW SUGGESTED
ADDING A FEW COUNTIES TO THE WIND ADVISORY.
PREV DISCUSSION... /ISSUED 344 AM CST WED JAN 18 2012/
DISCUSSION...
FORECAST CONCERNS IN THE SHORT TERM DEAL WITH ADVISORY CRITERIA WIND
SPEEDS ACROSS OUR WESTERN ZONES TODAY...AND TEMPERATURE FORECAST
THROUGH THE END OF THE WORK WEEK. ALSO OF IMPORTANCE WILL BE THE
POSSIBILITY OF FLURRIES LATE TONIGHT...AND THE CHANCE OF LIGHT SNOW
AND/OR FREEZING DRIZZLE EARLY FRIDAY MORNING.
WIND ADVISORY CONDITIONS ARE EXPECTED ACROSS PARTS OF WRN NEB TODAY.
THESE WEST WINDS ARE DEVELOPING AHEAD OF AN ARCTIC FRONT. A BLEND OF
500M AGL WINDS FROM THE NAM AND MAV AND MET GUIDANCE WERE USED FOR
SPEEDS. MOSGUIDE AND NAMDNG WAS USED FOR GUSTS WHICH SHOULD REACH
40KT ACROSS PARTS OF WRN NEB.
WARM AIR ADVECTION AND WESTERLY DOWNSLOPING WINDS WILL HELP PUSH
TEMPERATURES BACK NEAR IF NOT ABOVE SEASONAL AVERAGE THIS AFTERNOON
FOR MUCH OF THE CWA. THE EXCEPTION WILL BE THE NORTHERN REACHES OF
THE FORECAST AREA WHERE THE ABOVE MENTIONED COLD FRONT WILL DROP
SOUTH FROM THE DAKOTAS BRINGING ANOTHER ARCTIC PUSH OF COLD AIR.
LOOKING AT A WIDE RANGE OF HIGHS ONCE AGAIN ACROSS THE FORECAST
AREA...WITH THE WARMEST READINGS OVER SOUTHWEST NEBRASKA /READINGS
IN THE MID TO UPPER 40S/. OVER NORTHERN NEBRASKA...HIGHS WILL BE
REACHED EARLY IN THE DAY...AS CAA WILL TAKE HOLD AFTER THE NOON
HOUR...SO LOOKING FOR HIGHS ONLY IN THE 30S ALONG THE NIOBRARA RIVER
VALLEY.
FOR TONIGHT...CONTINUED THE MENTION OF FLURRIES ACROSS THE SAND
HILLS REGION OF NEBRASKA AS A SHORTWAVE RAPIDLY ADVANCES SOUTHEAST
FROM WESTERN CANADA TOWARD THE GREAT LAKES REGION. ALSO WENT AHEAD
AND INTRODUCED SLIGHT CHANCE POPS ACROSS NORTHERN NEBRASKA. WHILE THE
MODELS ARE STILL STRUGGLING ON THE TIMING OF THE PASSING BAROCLINIC
ZONE...THE NAM...GFS AND A LESSER EXTENT THE EURO DEVELOP QPF
OVERNIGHT TONIGHT. FLURRIES SEEM THE OPERATIVE MODE...HOWEVER
DECENT ISENTROPIC LIFT IN THE BAROCLINIC ZONE ALONG THE 285-295K
LAYERS INDICATE THE POTENTIAL FOR ACCUMULATION. A QUICK CHECK OF
PWATS INDICATE VALUES REACHING THE 75 PERCENTILE...SO
MOISTURE WILL BE AVAILABLE. POSSIBLE ACCUMULATIONS OF A QUARTER
TO A HALF INCH IS NOT OUT OF THE QUESTION LATE TONIGHT INTO TOMORROW
MORNING ALONG THE SOUTH DAKOTA BORDER...ESPECIALLY SINCE THE FALLING
SNOW WILL BE FLUFFY IN NATURE. ON TO OVERNIGHT LOWS TONIGHT...THE
GFS IS THE MOST PROGRESSIVE WITH THE COLD AIR DUMP...FOLLOWED BY THE
NAM AND EURO. THE MODELS SEEM TO CENTER ON THE AIRMASS REACHING -17C
AT 850MB BY 12Z THURSDAY OVER OUR NORTHERN ZONES. WITH THESE
READINGS...WOULDN/T BE SURPRISED TO SEE SUB ZERO READING ACROSS
NORTHERN NEBRASKA...UNLESS CLOUD COVER MODERATES TEMPERATURES. MAV
AND MET GUIDANCE INDICATES MINUS 9 AND 7 RESPECTIVELY AT VTN...WON/T
VENTURE THAT LOW YET...BUT ANY CLEARING WOULD ALLOW FOR THESE
READINGS...IF NOT COLDER. FURTHER SOUTH...SINGLE DIGIT READINGS
SEEM PLAUSIBLE...WITH THE EXCEPTION OF FAR SOUTHWEST NEBRASKA. WITH
THE HIGHER TERRAIN...THE COLD AIR IS STRUGGLING TO PUSH ANY FURTHER
WEST THAN THE COLORADO BORDER...SO MID TEENS WILL BE QUITE POSSIBLE
ACROSS THE SOUTHWESTERN ZONES EARLY TOMORROW. INTO THURSDAY
AFTERNOON...ARCTIC HIGH PRESSURE BUILDS EAST WITH RETURN SOUTHERLY
FLOW PUMPING H85 TEMPERATURES ABOVE 0C ACROSS THE SOUTHWEST. THIS
SETS THE STAGE FOR A WIDE RANGE OF HIGH TEMPERATURES OVER THE CWA.
LOOKING FOR HIGHS TO RETURN TO NEAR CLIMO OVER WESTERN AND SOUTHWEST
NEBRASKA...BUT REMAIN IN THE MID TEENS ACROSS NORTH CENTRAL
NEBRASKA.
FORECAST GETS INTERESTING THURSDAY NIGHT INTO FRIDAY...AS WARM AIR
ALOFT AND INCREASING MOISTURE COMBINE WITH A FRONTOGENETIC SUPPORT
TO PRODUCE LIGHT QPF OVER MUCH OF THE FORECAST AREA. THE
PREVIOUS FORECAST HAD INTRODUCED A SLIGHT CHANCE OF SNOW INTO THE
FORECAST...WILL CONTINUE...BUT ALSO INTRODUCE THE MENTION OF
FREEZING DRIZZLE. BUFR SOUNDINGS INDICATE TEMPERATURES ALOFT RISING
ABOVE 0C...WITH A SATURATED PROFILE INDICATIVE OF PERIODS OF FREEZING
RAIN. INTRODUCING FREEZING DRIZZLE IS A GOOD START...AND THEN CAN
GO FROM THERE...ESPECIALLY SINCE THESE SOUNDINGS INDICATE PERIODS OF
DRIER AIR IN THE MID LEVELS...MESSING WITH THE SEEDER FEEDER
PROCESSES.
LONG TERM...LOW CONFIDENCE IN THE EXTENDED AS THE MODELS ARE
STRUGGLING GREATLY ON RUN TO RUN CONSISTENCY AND GENERAL AGREEMENT.
IN FACT...ON FRIDAY THERE IS A GREATER THAN 15C DIFFERENCE IN H85
TEMPERATURES OVER PARTS OF THE CWA WHEN COMPARING THE GFS AND NAM.
WITH THE LACK OF AGREEMENT...GENERALLY SIDED WITH THE COLDER GFS
SOLUTION...WHICH WOULD SUGGEST BELOW AVERAGE HIGHS ON FRIDAY...WITH
THE EXCEPTION OF THE HIGHER TERRAIN OF SOUTHWEST AND WESTERN
NEBRASKA. FOR SATURDAY AND THE REST OF THE WEEKEND...MODELS
ACTUALLY DO AGREE ON WARMING TEMPERATURES...THUS TRENDED HIGHS BACK
INTO THE 40S AND 50S BOTH DAYS. BEYOND SUNDAY...SIGNIFICANT
DIFFERENCES BETWEEN THE THE LONGER RANGE MODELS WILL KEEP THE
FORECAST AS STATUS QUO...WITH ONLY SLIGHT CHANCE POPS GOING ACROSS
THE NORTH ON SUNDAY. OTHERWISE WILL KEEP THE EXTENDED DRY...WITH
NEAR SEASONAL TEMPERATURES UNTIL BETTER AGREEMENT IS DISPLAYED FROM
THE SOLUTIONS.
AVIATION...
VFR IS EXPECTED THROUGH 00Z. THEREAFTER AN ARCTIC FRONT WILL BEGIN
MOVING SOUTH THROUGH NRN NEB PRODUCING MVFR AND POSSIBLY IFR CIGS.
THE FRONT AND ASSOCIATED FLIGHT RESTRICTIONS COULD DROP AS FAR SOUTH
AS KOGA AND KLBF BY 12Z THURSDAY. ISOLATED FLURRIES ARE EXPECTED TO
ACCOMPANY THE FRONT AS IT MOVES SOUTH.
WINDS TODAY ARE EXPECTED TO INCREASE TO 27030G40KT ACROSS THE
SANDHILLS...MAINLY THE WRN SANDHILLS WITH LESSER SPEEDS EAST THROUGH
KTIF AND KBBW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FROM 9 AM THIS MORNING TO 5 PM MST THIS AFTERNOON
FOR NEZ004-022-023-035-056-057.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1032 PM EST THU JAN 19 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC STATES. THIS STORM WILL BRING MODERATE
ACCUMULATING SNOW TO THE SOUTHERN TIER AND CATSKILLS OF NEW YORK,
AND NORTHEASTERN PENNSYLVANIA.
&&
.NEAR TERM /THROUGH FRIDAY/...
10 PM UPDATE...SOME BIG CHANGES WITH THIS UPDATE. FIRST OFF...WE
GOT A REPORT OF 8" OF SNOW IN BOONVILLE FROM A SPOTTER THROUGH
FACEBOOK. WE CONFIRMED THIS AMOUNT WITH A FEW REPORTS OF AROUND 6"
IN THE SAME AREA. WITH CRITERIA FOR A WARNING BEING 7" IN 12 HOURS
OR 9" IN 24 HOURS...AND EXPECTING MORE SNOW DUE TO LAKE EFFECT
LATER TONIGHT...AN UPGRADE TO A WARNING WAS AN EASY CALL. TOUGHER
CALL ON WHAT TO CALL IT (LAKE EFFECT VS. WINTER STORM). AFTER
COORDINATION WITH BUFFALO AND ALBANY...DECIDED TO GO THE WINTER
STORM ROUTE SINCE THIS WOULD BE AN UPGRADE FROM THE ADVISORY WE
ALREADY HAD OUT...AND JUST MENTION THE TRANSITION TO LAKE EFFECT
SNOW IN THE PRODUCT ITSELF. FARTHER SOUTH AND EAST...AN AREA OF
SNOW HAS PRODUCED 1 TO 3 INCHES OF SNOW IN ISOLATED AREAS OF
CORTLAND...CHENANGO...BROOME...DELAWARE COUNTIES ALONG WITH SOME
OF NEPA. THIS IS IN ASSOCIATION WITH THE LEFT EXIT REGION OF A
JET. THESE AREAS MAY APPROACH 4" IN ISOLATED AREA WITH ANOTHER
INCH EXPECTED OVERNIGHT FROM A SQUALL LINE...BUT THE AVERAGE FOR
THIS WHOLE AREA WILL BE CLOSER TO 1 TO 2 INCHES...THUS NO
ADVISORY WILL BE ISSUED.
LAST BUT NOT LEAST...THE SQUALL LINE WE HAVE BEEN TRACKING IS NOW
MOVING THROUGH CENTRAL NY. THE LINE HAS HELD TOGETHER QUITE NICELY
AND WE STILL EXPECT A QUICK HALF TO 1.5 INCHES OF SNOW IN A BURST.
WE CONTINUE TO STRESS THAT THESE AMOUNTS ARE NOT HIGH BUT WILL
CREATE SLICK TRAVEL IN A SHORT PERIOD OF TIME. THE PREVIOUS AFD IS
BELOW...
730 PM UPDATE...THE FORECAST IS IN PRETTY GOOD SHAPE. SOME SNOW
HAS DEVELOPED NEAR THE BINGHAMTON AND NORWICH AREAS RECENTLY. THIS
IS RESPONSE TO A JET STREAK AT AROUND 400 MB ACROSS WEST CENTRAL
PA. THE SNOW OVER CENTRAL PA IS BEING CAUSED BY THE RIGHT ENTRANCE
REGION TO THE JET...WITH OUR LIGHT SNOW BEING CAUSED BY THE LEFT
EXIT REGION. AS THIS JET STREAK SLIDES SOUTHEAST AND WEAKENS
THROUGH 9 PM...EXPECT THE SNOW TO DIMINISH AND MOVE EAST.
NOW TO THE REAL ACTION. AN INTENSE LINE OF SNOW CONTINUES TO MARCH
EAST ACROSS WESTERN NY AND IS JUST ON THE DOORSTEPS OF OUR AREA.
OUR FIRST SPS HAS BEEN ISSUED AND WE WILL LIKELY TO CONTINUE TO
ISSUE SPECIAL WEATHER STATEMENTS THROUGH MIDNIGHT AS THE LINE HEADS
EAST. SNOWFALL AMOUNTS OF AN INCH OR SO ARE POSSIBLE WITH THE
LINE...BUT IT WILL BE THE FACT THAT THE SNOW WILL FALL IN SUCH A
SHORT PERIOD OF TIME THAT IS CAUSE FOR CONCERN. ROUGH TIMING IS
BETWEEN 8 PM AND 10 PM FOR THE WESTERN PART OF THE CWA...ALONG
I-81 IN NY BETWEEN 10 PM AND MIDNIGHT...AND THE SOUTHEASTERN CWA
BETWEEN MIDNIGHT AND 3 AM. THE MODELS DO SHOW THE LINE WEAKENING A
BIT AS IT MARCHES EAST...SO WE MAY SEE THE BIGGEST IMPACT TO OUR
CWA COMING BETWEEN NOW AND MIDNIGHT. THE REST OF THE FORECAST IS
IN GOOD SHAPE REGARDING THE TRANSITION TO LAKE EFFECT SNOW LATER
TONIGHT. THE PREVIOUS AFD IS BELOW...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
330 PM UPDATE...
HGTS BLD SUN NGT WITH MID AND LL WAA AHD OF A WRN LAKES LOW. LGT
PCPN SEEM PSBL WITH MUCH UNCERTAINTY ABT THE TEMP PROFILE. MIXED
PCPN SEEMS LIKELY WITH SFC TEMPS NEAR OR BLO FRZG...SO SOME FRZG
RAIN PSBL. LOW MVES SLWLY EAST AS AN OCCLUDED FNT RACES EWRD THRU
THE OH VLY AND WRN NY. TIMING PUSHES THE FNT THRU THE AREA MON
EVE...BUT WITH MODIFIED COLD AIR PUSHING IN FROM THE SW...DO NOT
XPCT A DRAMATIC TEMP DROP LATE MON INTO TUE. UPR LOW LIFTS NORTH
TUE AS THE TROF AXIS PASSES. AIR IS JUST NOT THAT COLD WITH H8
TEMPS FCSTD IN THE -6C TO -8C RANGE. XPCT SOME MOISTURE WITH THE
UPR TROF AND SOME MRGNL LE SNOW SHWRS INTO WED. LATE WED A SFC HI
OVER THE OH VLY BLDS IN BUT WITH ZONAL FLOW OVER THE FCST
AREA...TEMPS RATHER NEUTRAL AND WITH A WEAK SFC TROF AND APRCHG
WC...JUST SOME LGT PCPN IN THE AREA FOR THE END OF THE PD.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
630 PM UPDATE...
COLD FRONT IN WRN NY WILL CROSS THROUGH THE TAF SITES BETWEEN 2
AND 5Z. WITH THIS WILL BE IFR MODERATE SNOW FOR UP TO AN HOUR.
AHEAD OF THIS FRONT IS SOME MVFR VSBY AND CIG SNOW SHOWERS.
BEHIND THE FRONT WILL BE LAKE EFFECT FOR CENTRAL NY. RME SHOULD
STAY WITH MVFR/IFR CONDITIONS MOST OF THE NIGHT. THIS SINGLE BAND
WILL SHIFT SOUTH THROUGH SYR BETWEEN 9 AND 15Z. ITH AND BGM SHOULD
HAVE SOME MVFR CONDITIONS IN LIGHT SNOW SHOWERS OFF OF LAKE
ONTARIO AND THE FINGER LAKES LATE TONIGHT AND FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN DURING THE AFTN SHUTTING DOWN THE LAKE
EFFECT AND RETURNING ALL SITES TO VFR BY 19Z AND REMAINING VFR
THROUGH MOST OF THE EVENING.
S WINDS AT 5 TO 10 KTS SHIFTING TO SW JUST AHEAD OF THE FRONT THEN
TO THE W AND NW BEHIND THE FRONT. LATE FRI AFTN WINDS WILL BECOME
LIGHT AND VARIABLE.
.OUTLOOK...
FRI NGT...VFR BECOMING IFR AFTER MIDNIGHT WITH WIDESPREAD SNOW
MOVES IN.
SAT...IFR IN SNOW DURING THE MORNING IMPROVING TO VFR DURING THE
AFTN.
SAT NGT AND SUN...MAINLY VFR.
SUN NGT TO MON NGT..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 11 AM EST FRIDAY FOR NYZ018-036-
037.
WINTER STORM WARNING UNTIL 9 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP/HEDEN
SHORT TERM...DJP
LONG TERM...DGM
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
730 PM EST THU JAN 19 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC STATES. THIS STORM WILL BRING MODERATE
ACCUMULATING SNOW TO THE SOUTHERN TIER AND CATSKILLS OF NEW YORK,
AND NORTHEASTERN PENNSYLVANIA.
&&
.NEAR TERM /THROUGH FRIDAY/...
730 PM UPDATE...THE FORECAST IS IN PRETTY GOOD SHAPE. SOME SNOW
HAS DEVELOPED NEAR THE BINGHAMTON AND NORWICH AREAS RECENTLY. THIS
IS RESPONSE TO A JET STREAK AT AROUND 400 MB ACROSS WEST CENTRAL
PA. THE SNOW OVER CENTRAL PA IS BEING CAUSED BY THE RIGHT ENTRANCE
REGION TO THE JET...WITH OUR LIGHT SNOW BEING CAUSED BY THE LEFT
EXIT REGION. AS THIS JET STREAK SLIDES SOUTHEAST AND WEAKENS
THROUGH 9 PM...EXPECT THE SNOW TO DIMINISH AND MOVE EAST.
NOW TO THE REAL ACTION. AN INTENSE LINE OF SNOW CONTINUES TO MARCH
EAST ACROSS WESTERN NY AND IS JUST ON THE DOORSTEPS OF OUR AREA.
OUR FIRST SPS HAS BEEN ISSUED AND WE WILL LIKELY TO CONTINUE TO
ISSUE SPECIAL WEATHER STATEMENTS THROUGH MIDNIGHT AS THE LINE HEADS
EAST. SNOWFALL AMOUNTS OF AN INCH OR SO ARE POSSIBLE WITH THE
LINE...BUT IT WILL BE THE FACT THAT THE SNOW WILL FALL IN SUCH A
SHORT PERIOD OF TIME THAT IS CAUSE FOR CONCERN. ROUGH TIMING IS
BETWEEN 8 PM AND 10 PM FOR THE WESTERN PART OF THE CWA...ALONG
I-81 IN NY BETWEEN 10 PM AND MIDNIGHT...AND THE SOUTHEASTERN CWA
BETWEEN MIDNIGHT AND 3 AM. THE MODELS DO SHOW THE LINE WEAKENING A
BIT AS IT MARCHES EAST...SO WE MAY SEE THE BIGGEST IMPACT TO OUR
CWA COMING BETWEEN NOW AND MIDNIGHT. THE REST OF THE FORECAST IS
IN GOOD SHAPE REGARDING THE TRANSITION TO LAKE EFFECT SNOW LATER
TONIGHT. THE PREVIOUS AFD IS BELOW...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
330 PM UPDATE...
HGTS BLD SUN NGT WITH MID AND LL WAA AHD OF A WRN LAKES LOW. LGT
PCPN SEEM PSBL WITH MUCH UNCERTAINTY ABT THE TEMP PROFILE. MIXED
PCPN SEEMS LIKELY WITH SFC TEMPS NEAR OR BLO FRZG...SO SOME FRZG
RAIN PSBL. LOW MVES SLWLY EAST AS AN OCCLUDED FNT RACES EWRD THRU
THE OH VLY AND WRN NY. TIMING PUSHES THE FNT THRU THE AREA MON
EVE...BUT WITH MODIFIED COLD AIR PUSHING IN FROM THE SW...DO NOT
XPCT A DRAMATIC TEMP DROP LATE MON INTO TUE. UPR LOW LIFTS NORTH
TUE AS THE TROF AXIS PASSES. AIR IS JUST NOT THAT COLD WITH H8
TEMPS FCSTD IN THE -6C TO -8C RANGE. XPCT SOME MOISTURE WITH THE
UPR TROF AND SOME MRGNL LE SNOW SHWRS INTO WED. LATE WED A SFC HI
OVER THE OH VLY BLDS IN BUT WITH ZONAL FLOW OVER THE FCST
AREA...TEMPS RATHER NEUTRAL AND WITH A WEAK SFC TROF AND APRCHG
WC...JUST SOME LGT PCPN IN THE AREA FOR THE END OF THE PD.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
630 PM UPDATE...
COLD FRONT IN WRN NY WILL CROSS THROUGH THE TAF SITES BETWEEN 2
AND 5Z. WITH THIS WILL BE IFR MODERATE SNOW FOR UP TO AN HOUR.
AHEAD OF THIS FRONT IS SOME MVFR VSBY AND CIG SNOW SHOWERS.
BEHIND THE FRONT WILL BE LAKE EFFECT FOR CENTRAL NY. RME SHOULD
STAY WITH MVFR/IFR CONDITIONS MOST OF THE NIGHT. THIS SINGLE BAND
WILL SHIFT SOUTH THROUGH SYR BETWEEN 9 AND 15Z. ITH AND BGM SHOULD
HAVE SOME MVFR CONDITIONS IN LIGHT SNOW SHOWERS OFF OF LAKE
ONTARIO AND THE FINGER LAKES LATE TONIGHT AND FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN DURING THE AFTN SHUTTING DOWN THE LAKE
EFFECT AND RETURNING ALL SITES TO VFR BY 19Z AND REMAINING VFR
THROUGH MOST OF THE EVENING.
S WINDS AT 5 TO 10 KTS SHIFTING TO SW JUST AHEAD OF THE FRONT THEN
TO THE W AND NW BEHIND THE FRONT. LATE FRI AFTN WINDS WILL BECOME
LIGHT AND VARIABLE.
.OUTLOOK...
FRI NGT...VFR BECOMING IFR AFTER MIDNIGHT WITH WIDESPREAD SNOW
MOVES IN.
SAT...IFR IN SNOW DURING THE MORNING IMPROVING TO VFR DURING THE
AFTN.
SAT NGT AND SUN...MAINLY VFR.
SUN NGT TO MON NGT..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 11 AM EST FRIDAY FOR NYZ018-036-
037.
WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP/HEDEN
SHORT TERM...DJP
LONG TERM...DGM
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
658 PM EST THU JAN 19 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC STATES. THIS STORM WILL BRING MODERATE
ACCUMULATING SNOW TO THE SOUTHERN TIER AND CATSKILLS OF NEW YORK,
AND NORTHEASTERN PENNSYLVANIA.
&&
.NEAR TERM /THROUGH FRIDAY/...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
330 PM UPDATE...
HGTS BLD SUN NGT WITH MID AND LL WAA AHD OF A WRN LAKES LOW. LGT
PCPN SEEM PSBL WITH MUCH UNCERTAINTY ABT THE TEMP PROFILE. MIXED
PCPN SEEMS LIKELY WITH SFC TEMPS NEAR OR BLO FRZG...SO SOME FRZG
RAIN PSBL. LOW MVES SLWLY EAST AS AN OCCLUDED FNT RACES EWRD THRU
THE OH VLY AND WRN NY. TIMING PUSHES THE FNT THRU THE AREA MON
EVE...BUT WITH MODIFIED COLD AIR PUSHING IN FROM THE SW...DO NOT
XPCT A DRAMATIC TEMP DROP LATE MON INTO TUE. UPR LOW LIFTS NORTH
TUE AS THE TROF AXIS PASSES. AIR IS JUST NOT THAT COLD WITH H8
TEMPS FCSTD IN THE -6C TO -8C RANGE. XPCT SOME MOISTURE WITH THE
UPR TROF AND SOME MRGNL LE SNOW SHWRS INTO WED. LATE WED A SFC HI
OVER THE OH VLY BLDS IN BUT WITH ZONAL FLOW OVER THE FCST
AREA...TEMPS RATHER NEUTRAL AND WITH A WEAK SFC TROF AND APRCHG
WC...JUST SOME LGT PCPN IN THE AREA FOR THE END OF THE PD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
630 PM UPDATE...
COLD FRONT IN WRN NY WILL CROSS THROUGH THE TAF SITES BETWEEN 2
AND 5Z. WITH THIS WILL BE IFR MODERATE SNOW FOR UP TO AN HOUR.
AHEAD OF THIS FRONT IS SOME MVFR VSBY AND CIG SNOW SHOWERS.
BEHIND THE FRONT WILL BE LAKE EFFECT FOR CENTRAL NY. RME SHOULD
STAY WITH MVFR/IFR CONDITIONS MOST OF THE NIGHT. THIS SINGLE BAND
WILL SHIFT SOUTH THROUGH SYR BETWEEN 9 AND 15Z. ITH AND BGM SHOULD
HAVE SOME MVFR CONDITIONS IN LIGHT SNOW SHOWERS OFF OF LAKE
ONTARIO AND THE FINGER LAKES LATE TONIGHT AND FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN DURING THE AFTN SHUTTING DOWN THE LAKE
EFFECT AND RETURNING ALL SITES TO VFR BY 19Z AND REMAINING VFR
THROUGH MOST OF THE EVENING.
S WINDS AT 5 TO 10 KTS SHIFTING TO SW JUST AHEAD OF THE FRONT THEN
TO THE W AND NW BEHIND THE FRONT. LATE FRI AFTN WINDS WILL BECOME
LIGHT AND VARIABLE.
.OUTLOOK...
FRI NGT...VFR BECOMING IFR AFTER MIDNIGHT WITH WIDESPREAD SNOW
MOVES IN.
SAT...IFR IN SNOW DURING THE MORNING IMPROVING TO VFR DURING THE
AFTN.
SAT NGT AND SUN...MAINLY VFR.
SUN NGT TO MON NGT..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 11 AM EST FRIDAY FOR NYZ018-036-
037.
WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP
SHORT TERM...DJP
LONG TERM...DGM
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
640 AM EST WED JAN 18 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING. HIGH
PRESSURE WILL BUILD ACROSS THE AREA TONIGHT AND THURSDAY. A WEAK
FRONT WILL DROP SOUTH INTO THE AREA FRIDAY. LOW PRESSURE WILL
DEVELOP TO OUR WEST FRIDAY AND SATURDAY WITH UNSETTLED WEATHER
POSSIBLE THROUGH THE WEEKEND. ABOVE-NORMAL TEMPERATURES ARE EXPECTED
NEXT WEEK WITH SOUTHERLY WINDS.
&&
.NEAR TERM /THROUGH 6 AM THURSDAY/...
AS OF 630 AM WEDNESDAY...THE STRONG COLD FRONT SHOWS UP VERY WELL ON
DOPPLER RADAR IMAGERY...EXTENDING FROM LUMBERTON THROUGH DILLON AND
DARLINGTON. THE BOUNDARY SHOULD CONTINUE MAKING GOOD SOUTHEASTWARD
PROGRESS THIS MORNING AND WILL BE OFFSHORE BY 11 AM. SHOWER ACTIVITY
HAS BECOME MORE SCATTERED IN COVERAGE ACROSS SOUTH CAROLINA BUT A
CONCENTRATED BATCH OF RAIN IS SET TO MOVE EAST ACROSS SOUTHEASTERN
NORTH CAROLINA IN THE NEXT TWO HOURS. TODAY`S HIGH TEMPERATURES ARE
ESSENTIALLY WHAT YOU HAVE ON THE THERMOMETER RIGHT NOW: UPPER 50S
MOST AREAS. BEHIND THE FRONT TEMPERATURES SHOULD FALL INTO THE LOWER
50S BY EARLY AFTERNOON...FLAT-LINING THROUGH 4 PM OR SO...THEN
FALLING PRECIPITOUSLY TONIGHT AS THE SURFACE HIGH MOVES ALMOST
OVERHEAD LATE.
WE HAVE USED THE LATEST HRRR AND RUC MODELS TO HELP ADJUST THE
FRONTAL TIMING IN THE FORECAST GRIDS THROUGH THE MORNING HOURS. THE
HRRR HAS BEEN PARTICULARLY USEFUL SHOWING THE INCREASING NE-SW
ORIENTATION THE FRONT HAS TAKEN OVER THE PAST FEW HOURS. THIS MEANS
GEORGETOWN WILL PROBABLY THE LAST LOCATION IN OUR FORECAST AREA TO
SEE THE FRONT PUSH THROUGH...POSSIBLY AS LATE AS 11 AM TO NOON.
SKIES SHOULD CLEAR OUT FROM WEST TO EAST LATE THIS MORNING INTO THE
AFTERNOON...REMAINING MOSTLY CLEAR TONIGHT EXCEPT FOR INCREASING
THIN CIRRUS LATE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PROGRESSIVE WEATHER PATTERN SFC AND ALOFT TO
RULE THE SHORT TERM. THE ILM CWA WILL BE UNDER THE INFLUENCE OF A
LOW AMPLITUDE LONGWAVE TROF THU WHICH WILL TRANSLATE TO MORE OF A
WEST TO EAST ZONAL FLOW AT 5H BY FRIDAY NIGHT. AT THE SFC...WEAK SFC
RIDGING TO SLIDE OFF THE SE U.S. COAST BY EARLY FRIDAY...ALLOWING A
WEAK BUT DRY COLD FRONT TO APPROACH LATE THU NITE AND PUSH ACROSS
THE ILM CWA BEFORE STALLING SOUTH OF THE FA AS IT BECOMES PARALLEL
TO THE UPPER FLOW. THE NAM SEEMS LIKE THE OUTLIER BY STALLING THE
FRONT ACROSS THE FA WHEREAS THE GFS AND EUROPEAN SLIDE IT FAR ENOUGH
SOUTH B4 STALLING. MODELS HINT AT WEAK WEDGE-ING POSSIBLE FRIDAY
NIGHT. DUE TO THE PROGRESSIVE NATURE OF THE FLOW ESPECIALLY
ALOFT...WILL NOT BUY THIS SOLUTION. WILL STAY AT OR SLITELY COOLER
THAN GFS MOS GUIDANCE THRU THE SHORT TERM...WHICH BASICALLY RIGHT AT
CLIMATOLOGICAL NORMS FOR THIS TIME OF YEAR.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...THE LONG TERM WILL BE HIGHLIGHTED WITH
ZONAL FLOW ALOFT AT THE START...TRANSLATING TO A LOW AMPLITUDE
LONGWAVE UPPER TROF BY THE BEGINNING OF NEXT WEEK. GFS A BIT MORE
VIGOROUS THAN THE EUROPEAN WITH A 5H S/W TROF FROM THE DESERT SW
THAT TRACKS ENE AND INTERACTS WITH THE STALLED FRONT BY PRODUCING AN
AREA OF LOW PRESSURE ON THE FRONT. EUROPEAN AND GFS KEEP THE ACTUAL
SFC LOW INLAND AND NORTH OF THE ILM CWA AS IT MOVES NE OF THE FA BY
SUNDAY. LOOK FOR ITS ASSOCIATED SFC COLD FRONT TO DROP AND STALL
ACROSS OR JUST SOUTH OF THE ILM CWA. HAVE INDICATED DECENT CHANCE
POPS DURING THE LOWS PASSAGE AND AHEAD OF ITS COLD FRONT DURING
SATURDAY INTO SATURDAY NIGHT. NO PCPN TYPE ISSUES WITH TEMPS ON THE
MILD SIDE. AS FOR EARLY NEXT WEEK...POTENTIAL FOR BLOWN FORECAST TO
EXIST WITH A STATIONARY SFC FRONT TO LIE ACROSS OR JUST SOUTH OF THE
ILM CWA...WITH LONG-TERM MODELS INDICATING A POTENTIAL SFC LOW TO
TRACK ALONG AND AFFECT THE ILM CWA. FOR NOW...ONLY INDICATED 20-30
POPS LATE SUNDAY INTO TUESDAY AND WILL AWAIT FURTHER MODEL
CONSENSUS. EITHER SIDE OF THE STATIONARY FRONT COULD SEE A 20 DEGREE
TEMPERATURE DIFFERENTIAL. FOR NOW...STAYED ON THE MILDER/WARMER SIDE
OF GUIDANCE WHICH KEEPS TEMPS ABOVE CLIMO NORMS. COULD EVEN SEE 70+
DEGREE READINGS ON MONDAY AND/OR TUESDAY IF THE FA REMAINS ON THE
SOUTH SIDE OF THE FRONTAL BOUNDARY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...FRONTAL BOUNDARY POISED JUST WEST OF THE CWA...AND WILL
BE BLASTING THROUGH OVER THE NEXT SEVERAL HOURS. AHEAD OF THE
FRONT...LOOK FOR GUSTY SOUTHWEST FLOW WITH INTERMITTENT MVFR/NEAR
IFR CONDITIONS...PARTICULARLY AT THE WESTERN TERMINALS. LOOK FOR
FROPA FROM 12-13Z INLAND...AND AROUND 14Z AT THE COAST. BEHIND THE
FRONT...CONDITIONS WILL SLOWLY IMPROVE TO VFR...WITH A VEERING WIND
TO THE NORTH...GUSTY BY MID MORNING. SHOWERS MAY LINGER ALONG THE
COAST THROUGH 15Z...WITH VFR EXPECTED BY AFTERNOON.
TONIGHT...DIMINISHING NORTH WIND WITH SCATTERED SKIES.
EXTENDED OUTLOOK...SLIGHT CHANCE MVFR VISIBILITIES THURSDAY AND
FRIDAY MORNINGS. LOW CONFIDENCE FOR SHOWERS SATURDAY EVENING INTO
SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...WINDS/SEAS AND SHOWER COVERAGE MATCHES THE
PREVIOUS FORECAST. NO SIGNIFICANT CHANGES ARE NEEDED THIS MORNING.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
A STRONG COLD FRONT IN THE WESTERN CAROLINAS WILL MOVE EAST AND OFF
THE COAST AROUND MID-MORNING. SOUTHWEST WINDS AHEAD OF THE FRONT
WILL ABRUPTLY SHIFT TO THE NORTH AS COLDER AIR POURS OFFSHORE BEHIND
THE FRONT. SO FAR THIS MORNING THE STRONGEST WINDS HAVE REMAINED
15-20+ MILES OFFSHORE WHERE WATER AND AIR TEMPERATURES ARE HIGHEST.
THE COOLER CONDITIONS NEARSHORE HELP INSULATE THE OCEAN SURFACE FROM
MUCH STRONGER WINDS ONLY 500-1000 FEET UP. THIS REDUCTION IN WIND IS
ALSO PRODUCING MUCH LOWER SEA HEIGHTS THAN ONE MIGHT EXPECT AHEAD OF
SUCH A STRONG FRONT. NORTH WINDS THIS AFTERNOON WILL BECOME
NORTHEAST TONIGHT WITH WIND SPEEDS REDUCING TO 15 KNOTS OR LESS AS
HIGH PRESSURE MOVES INTO NORTH CAROLINA AND VIRGINIA.
THE SMALL CRAFT ADVISORY WILL REMAIN POSTED THROUGH 1 PM FOR THE NC
WATERS...WITH AN EXERCISE CAUTION HEADLINE FOR THE SC WATERS. THERE
IS SOME POTENTIAL THAT 20 KNOT WINDS MAY CONTINUE INTO THE MIDDLE OF
THE AFTERNOON WHICH MAY NECESSITATE AN EXTENSION OF THE EXERCISE
CAUTION HEADLINE. SEAS WILL SUBSIDE TONIGHT WITH THE LIGHTER WIND
SPEEDS DEVELOPING.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...ELONGATED CENTER OF HIGH PRESSURE TO
PROGRESS ACROSS THE ILM WATERS THURSDAY THEN SLIDE FURTHER EAST THU
NIGHT. THIS WILL ALLOW A COLD FRONT BASICALLY TO BACKDOOR THE ILM
WATERS FROM THE NORTH DURING FRIDAY BEFORE TEMPORARILY STALLING JUST
SOUTH OF THE WATERS LATE FRIDAY. MODELS INDICATE THE VEERING WIND
FROM LIGHT NE EARLY THURSDAY VEERING TO THE SW AHEAD OF THE FRONT
THU NIGHT INTO FRIDAY. HAVE TONED DOWN THE SW WIND SPEEDS AHEAD OF
THE FRONT DUE TO WAA WINDS PUSHING ACROSS SSTS IN THE 50S...WHICH
WILL WILL HAVE DIFFICULTY MIXING DOWN TO THE OCEAN SFC. WILL HAVE TO
RELY ON THE TEMPORARILY TIGHTENING OF THE SFC PG TO GET THESE HIER
WINDS BY EARLY FRI. AS FOR SEAS...AN EASTERLY 8-10 SECOND 1-2 FOOT
GROUND SWELL WILL OCCASIONALLY MIX WITH WEAK NE WIND WAVES
THURSDAY...THEN BECOME MORE DOMINATED BY SW WIND DRIVEN SHORT PERIOD
WAVES THU NITE INTO FRIDAY. OVERALL...WINDS AND SEAS TO STAY BELOW
SCA THRESHOLDS.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...FOR SATURDAY INTO SUNDAY THE STALLED FRONT
TO MEANDER ACROSS THE ILM WATERS AND INCREASE THE POTENTIAL FOR A
BUSTED FORECAST. FOR THE MOST PART...INDICATED THE STALLED FRONT
RETURNING NORTH OF THE AREA SATURDAY RESULTING WITH INCREASING SW
WINDS. THE LAST SFC LOW TO EXIT NE OF THE ILM CWA LATE
SUNDAY...ALLOWING THE COLD FRONT TO DRIFT BACK TO THE SOUTH LATE
SUNDAY INTO SUNDAY NIGHT. MODELS DIFFER ON THE SFC PRESSURE GRADIENT
AS WELL AS WHERE THE FINAL RESTING GROUND OF THE COLD FRONT. WILL
INDICATE INCREASING SEAS FROM SW WINDS...JUST NOT AS LARGE AS
WAVEWATCH3 GUIDANCE INDICATES. HAVE LEANED CLOSER TO SWAN DUE TO
BETTER HANDLE OF WAA WINDS OVER COOLER SHELF WATERS. WILL HAVE
BORDERLINE SCEC OR SCA CONDITIONS LATE SATURDAY INTO SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
300 AM EST WED JAN 18 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING. SHOWERS AND AN
ISOLATED THUNDERSTORM COULD PRECEDE THE FRONT. HIGH PRESSURE WILL
BUILD ACROSS THE AREA LATE TODAY AND THURSDAY...BRINGING DRY AND
SEASONABLE TEMPERATURES. A WEAK FRONT WILL DROP SOUTH INTO THE AREA
LATE FRIDAY BEFORE TEMPORARILY STALLING. AREAS OF LOW PRESSURE WILL
RIDE E TO NE ALONG THE FRONT KEEPING THE AREA UNSETTLED INTO THE
WEEKEND. WITH THE FRONT STALLED NORTH OF THE AREA INTO EARLY NEXT
WEEK...THE AREA WILL EXPERIENCE 70 PLUS DEGREE HIGHS DURING EARLY
NEXT WEEK. THE FRONT WILL FINALLY DROP SOUTH OF THE AREA BY THE
MIDDLE OF NEXT WEEK WITH A RETURN TO NEAR NORMAL TEMPERATURES
&&
.NEAR TERM /THROUGH 6 AM THURSDAY/...
AS OF 300 AM WEDNESDAY...A STRONG COLD FRONT CURRENTLY IN THE
WESTERN PIEDMONT OF THE CAROLINAS WILL SWEEP EAST AND OFFSHORE
BEFORE NOON. THE MILD AIRMASS WE HAVE ENJOYED FOR THE PAST 24 HOURS
WILL BE PUSHED OFFSHORE...REPLACED BY MUCH COLDER AIR ORIGINATING
OVER THE UPPER MIDWEST STATES. UNTIL THE FRONT ARRIVES...WIDESPREAD
SHOWERS WILL CONTINUE WITH STORM-TOTAL RAINFALL AMOUNTS AVERAGING A
THIRD OF AN INCH.
THE TIMING OF THE FRONT WILL BE OF TREMENDOUS IMPORTANCE IN OUR HIGH
TEMPERATURE FORECASTS FOR TODAY. FOR NWS VERIFICATION PURPOSES THE
HIGH TEMPERATURE IS DEFINED AS THE HIGHEST READING OBSERVED WITHIN
THE 12Z-00Z WINDOW...OR 7AM-7PM. SINCE THE FRONT WILL BE VERY NEAR
BOTH LBT AND FLO AT 7 AM THERE IS A SIGNIFICANT POTENTIAL TO BUST
THE HIGH AT THESE TWO LOCATIONS. THE 04Z AND 05Z HRRR RUNS APPEAR TO
BE VERIFYING VERY WELL WITH THE FRONTAL POSITION TO OUR WEST...AND
BOTH ARE ABOUT AN HOUR SLOWER THAN THE POSITION FORECAST BY THE 00Z
GFS. GFS LAMP GUIDANCE (SORT OF A RAPID-UPDATE MOS ADJUSTING THE
LATEST GFS RUN EACH HOUR) ALSO IMPLIES A SLOWER MOVEMENT OF THE
FRONT WITH ITS WIND SHIFT TIMING AT LBT AND FLO. WE ARE THEREFORE
FORECASTING HIGHS SEVERAL DEGREES ABOVE MOS GUIDANCE AT ALL SITES
TODAY...PARTICULARLY EAST OF I-95. AFTER THE FRONT MOVES THROUGH
TEMPERATURES WILL CRASH INTO THE UPPER 40S TO LOWER 50S.
EVEN WITH GRADUALLY CLEARING SKIES THIS AFTERNOON COLD ADVECTION
WILL OFFSET MUCH OF OUR INSOLATION...WITH A NEARLY STEADY
TEMPERATURE CURVE EXPECTED NOON THROUGH 4 PM. TEMPERATURES WILL THEN
FALL PRECIPITOUSLY TONIGHT AS THE SURFACE HIGH MOVES ALMOST OVERHEAD
LATE. LOWS SHOULD GENERALLY REACH THE UPPER 20S AWAY FROM THE COAST.
ONE FACTOR THAT WILL KEEP TEMPERATURES FROM FALLING DEEP INTO THE
20S TONIGHT WILL BE SOME CIRRUS CLOUDS ADVECTING OVERHEAD. BOTH THE
00Z NAM AND GFS SHOW 200-400 MB LAYER AVERAGE RELATIVE HUMIDITY IN
THE 70-90 PERCENT RANGE PERIODICALLY AFTER 03Z THIS EVENING.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PROGRESSIVE WEATHER PATTERN SFC AND ALOFT TO
RULE THE SHORT TERM. THE ILM CWA WILL BE UNDER THE INFLUENCE OF A
LOW AMPLITUDE LONGWAVE TROF THU WHICH WILL TRANSLATE TO MORE OF A
WEST TO EAST ZONAL FLOW AT 5H BY FRIDAY NIGHT. AT THE SFC...WEAK SFC
RIDGING TO SLIDE OFF THE SE U.S. COAST BY EARLY FRIDAY...ALLOWING A
WEAK BUT DRY COLD FRONT TO APPROACH LATE THU NITE AND PUSH ACROSS
THE ILM CWA BEFORE STALLING SOUTH OF THE FA AS IT BECOMES PARALLEL
TO THE UPPER FLOW. THE NAM SEEMS LIKE THE OUTLIER BY STALLING THE
FRONT ACROSS THE FA WHEREAS THE GFS AND EUROPEAN SLIDE IT FAR ENOUGH
SOUTH B4 STALLING. MODELS HINT AT WEAK WEDGE-ING POSSIBLE FRIDAY
NIGHT. DUE TO THE PROGRESSIVE NATURE OF THE FLOW ESPECIALLY
ALOFT...WILL NOT BUY THIS SOLUTION. WILL STAY AT OR SLITELY COOLER
THAN GFS MOS GUIDANCE THRU THE SHORT TERM...WHICH BASICALLY RIGHT AT
CLIMATOLOGICAL NORMS FOR THIS TIME OF YEAR.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...THE LONG TERM WILL BE HIGHLIGHTED WITH
ZONAL FLOW ALOFT AT THE START...TRANSLATING TO A LOW AMPLITUDE
LONGWAVE UPPER TROF BY THE BEGINNING OF NEXT WEEK. GFS A BIT MORE
VIGOROUS THAN THE EUROPEAN WITH A 5H S/W TROF FROM THE DESERT SW
THAT TRACKS ENE AND INTERACTS WITH THE STALLED FRONT BY PRODUCING AN
AREA OF LOW PRESSURE ON THE FRONT. EUROPEAN AND GFS KEEP THE ACTUAL
SFC LOW INLAND AND NORTH OF THE ILM CWA AS IT MOVES NE OF THE FA BY
SUNDAY. LOOK FOR ITS ASSOCIATED SFC COLD FRONT TO DROP AND STALL
ACROSS OR JUST SOUTH OF THE ILM CWA. HAVE INDICATED DECENT CHANCE
POPS DURING THE LOWS PASSAGE AND AHEAD OF ITS COLD FRONT DURING
SATURDAY INTO SATURDAY NIGHT. NO PCPN TYPE ISSUES WITH TEMPS ON THE
MILD SIDE. AS FOR EARLY NEXT WEEK...POTENTIAL FOR BLOWN FORECAST TO
EXIST WITH A STATIONARY SFC FRONT TO LIE ACROSS OR JUST SOUTH OF THE
ILM CWA...WITH LONG-TERM MODELS INDICATING A POTENTIAL SFC LOW TO
TRACK ALONG AND AFFECT THE ILM CWA. FOR NOW...ONLY INDICATED 20-30
POPS LATE SUNDAY INTO TUESDAY AND WILL AWAIT FURTHER MODEL
CONSENSUS. EITHER SIDE OF THE STATIONARY FRONT COULD SEE A 20 DEGREE
TEMPERATURE DIFFERENTIAL. FOR NOW...STAYED ON THE MILDER/WARMER SIDE
OF GUIDANCE WHICH KEEPS TEMPS ABOVE CLIMO NORMS. COULD EVEN SEE 70+
DEGREE READINGS ON MONDAY AND/OR TUESDAY IF THE FA REMAINS ON THE
SOUTH SIDE OF THE FRONTAL BOUNDARY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT GRADUALLY DETERIORATING CONDITIONS DUE TO SHOWERS
AND LOWERED VISIBILITY/CIGS WITH AN APPROACHING COLD FRONT. CURRENT
RADAR DEPICTS AN AREA OF SHOWERS ACROSS THE INLAND SITES...WITH
SCATTERED SHOWERS DEVELOPING AHEAD OF THIS ACTIVITY APPROACHING THE
COASTAL SITES. LOW LEVEL CLOUDS WILL CONTINUE TO THICKEN AND
OCCASIONALLY LOWER INTO THE LOW MVFR RANGE...PERSISTING UNTIL THE
FRONT HAS MOVED THROUGH THE AREA 12-15Z WEDNESDAY. AHEAD OF THE
FRONT...SOUTHWEST FLOW WILL CONTINUE WITH WINDS 12G18 KTS.
TIME-HEIGHT ANALYSIS...FCST SOUNDINGS AND OTHER MODEL GUIDANCE ALL
SUPPORT A DEEP LAYER OF MOISTURE UP THROUGH 18Z WED. THEREFORE
ANTICIPATE RAIN TO PERSIST INTO THE MORNING HOURS. WOULD ANTICIPATE
WITH HEAVIER RAIN THAT VISIBILITIES AND CIGS WILL DROP TO MVFR/NEAR
IFR STATUS AT MOST SITES. HOWEVER...CONFIDENCE IS LOW AT THIS TIME
REGARDING IFR STATUS. AS THE FROPA MOVES FROM WEST TO EAST THIS
MORNING...WINDS WILL SHIFT FROM SOUTHWEST TO GENERALLY NORTH...WITH
WINDS GUSTY. CONDITIONS WILL IMPROVE BEHIND THE FRONT...BACK TO VFR
BY THIS AFTERNOON. ANTICIPATE NORTH WINDS TO BECOME LIGHT AFTER
SUNSET.
EXTENDED OUTLOOK...SLIGHT CHANCE MVFR VISIBILITIES THURSDAY AND
FRIDAY MORNINGS. LOW CONFIDENCE FOR SHOWERS SATURDAY EVENING INTO
SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...A STRONG COLD FRONT IN THE WESTERN
CAROLINAS WILL MOVE EAST AND OFF THE COAST AROUND MID-MORNING.
SOUTHWEST WINDS AHEAD OF THE FRONT WILL ABRUPTLY SHIFT TO THE NORTH
AS COLDER AIR POURS OFFSHORE BEHIND THE FRONT. SO FAR THIS MORNING
THE STRONGEST WINDS HAVE REMAINED 15-20+ MILES OFFSHORE WHERE WATER
AND AIR TEMPERATURES ARE HIGHEST. THE COOLER CONDITIONS NEARSHORE
HELP INSULATE THE OCEAN SURFACE FROM MUCH STRONGER WINDS ONLY
500-1000 FEET UP. THIS REDUCTION IN WIND IS ALSO PRODUCING MUCH
LOWER SEA HEIGHTS THAN ONE MIGHT EXPECT AHEAD OF SUCH A STRONG
FRONT. NORTH WINDS THIS AFTERNOON WILL BECOME NORTHEAST TONIGHT WITH
WIND SPEEDS REDUCING TO 15 KNOTS OR LESS AS HIGH PRESSURE MOVES INTO
NORTH CAROLINA AND VIRGINIA.
THE SMALL CRAFT ADVISORY WILL REMAIN POSTED THROUGH 1 PM FOR THE NC
WATERS...WITH AN EXERCISE CAUTION HEADLINE FOR THE SC WATERS. THERE
IS SOME POTENTIAL THAT 20 KNOT WINDS MAY CONTINUE INTO THE MIDDLE OF
THE AFTERNOON WHICH MAY NECESSITATE AN EXTENSION OF THE EXERCISE
CAUTION HEADLINE. SEAS WILL SUBSIDE TONIGHT WITH THE LIGHTER WIND
SPEEDS DEVELOPING.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...ELONGATED CENTER OF HIGH PRESSURE TO
PROGRESS ACROSS THE ILM WATERS THURSDAY THEN SLIDE FURTHER EAST THU
NIGHT. THIS WILL ALLOW A COLD FRONT BASICALLY TO BACKDOOR THE ILM
WATERS FROM THE NORTH DURING FRIDAY BEFORE TEMPORARILY STALLING JUST
SOUTH OF THE WATERS LATE FRIDAY. MODELS INDICATE THE VEERING WIND
FROM LIGHT NE EARLY THURSDAY VEERING TO THE SW AHEAD OF THE FRONT
THU NIGHT INTO FRIDAY. HAVE TONED DOWN THE SW WIND SPEEDS AHEAD OF
THE FRONT DUE TO WAA WINDS PUSHING ACROSS SSTS IN THE 50S...WHICH
WILL WILL HAVE DIFFICULTY MIXING DOWN TO THE OCEAN SFC. WILL HAVE TO
RELY ON THE TEMPORARILY TIGHTENING OF THE SFC PG TO GET THESE HIER
WINDS BY EARLY FRI. AS FOR SEAS...AN EASTERLY 8-10 SECOND 1-2 FOOT
GROUND SWELL WILL OCCASIONALLY MIX WITH WEAK NE WIND WAVES
THURSDAY...THEN BECOME MORE DOMINATED BY SW WIND DRIVEN SHORT PERIOD
WAVES THU NITE INTO FRIDAY. OVERALL...WINDS AND SEAS TO STAY BELOW
SCA THRESHOLDS.
.LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...FOR SATURDAY INTO SUNDAY THE STALLED FRONT
TO MEANDER ACROSS THE ILM WATERS AND INCREASE THE POTENTIAL FOR A
BUSTED FORECAST. FOR THE MOST PART...INDICATED THE STALLED FRONT
RETURNING NORTH OF THE AREA SATURDAY RESULTING WITH INCREASING SW
WINDS. THE LAST SFC LOW TO EXIT NE OF THE ILM CWA LATE
SUNDAY...ALLOWING THE COLD FRONT TO DRIFT BACK TO THE SOUTH LATE
SUNDAY INTO SUNDAY NIGHT. MODELS DIFFER ON THE SFC PRESSURE GRADIENT
AS WELL AS WHERE THE FINAL RESTING GROUND OF THE COLD FRONT. WILL
INDICATE INCREASING SEAS FROM SW WINDS...JUST NOT AS LARGE AS
WAVEWATCH3 GUIDANCE INDICATES. HAVE LEANED CLOSER TO SWAN DUE TO
BETTER HANDLE OF WAA WINDS OVER COOLER SHELF WATERS. WILL HAVE
BORDERLINE SCEC OR SCA CONDITIONS LATE SATURDAY INTO SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRARMSTRONG
SHORT TERM...DOUGCH
LONG TERM...DOUGCH
AVIATION...TRARMSTRONG/SGLACORTE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
629 AM EST WED JAN 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTROL THE WEATHER OVER THE OHIO VALLEY
TODAY...WITH SNOW SHOWERS TAPERING OFF BY LATE MORNING. LOW PRESSURE
WILL MOVE THROUGH THE GREAT LAKES ON THURSDAY...WITH A COLD FRONT
PROVIDING A CHANCE OF SHOW FOR THE REGION. ANOTHER WEATHER
DISTURBANCE WILL BRING MIXED PRECIPITATION FOR FRIDAY NIGHT AND
SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW SHOWERS AND FLURRIES HAVE PERSISTED OVER THE REGION A BIT
LONGER THAN PREVIOUSLY ANTICIPATED...AND CERTAINLY LONGER THAN
DEPICTED BY THE PRIMARY SUITE OF MODELS. THE HRRR WAS HELPFUL IN
DETERMINING THE EXTENT OF THE REMAINING SNOWFALL...AND ITS GRADUAL
DIMINISHING OVER THE COURSE OF THE MORNING.
SKIES WILL GRADUALLY CLEAR FROM WEST TO EAST...AS HIGH PRESSURE
MOVES INTO THE AREA AND GETS STRETCHED OUT SW-TO-NE. THE COOL AIR
MASS WILL KEEP TEMPERATURES FROM RISING SIGNIFICANTLY...WITH HIGHS
IN THE FORECAST ABOUT 5 DEGREES BELOW CLIMATOLOGY. WINDS WILL
SHIFT FROM NW (COLD ADVECTION) TO SW (WARM ADVECTION) LATE IN THE
DAY...BUT NOT SOON ENOUGH TO RAISE TEMPERATURES IN THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERE ARE TWO MAIN CONCERNS FOR THE SHORT TERM OF THE FORECAST.
THE FIRST IS A COLD FRONT WITH SNOW ON THURSDAY...AND THE SECOND
IS A SYSTEM BRINGING MIXED PRECIPITATION ON FRIDAY NIGHT INTO
SATURDAY.
WARM ADVECTION WILL BEGIN TONIGHT ON SOUTHWESTERLY WINDS...AS
SURFACE HIGH PRESSURE MOVES EAST OF THE REGION. A COLD FRONT WILL
MOVE SOUTHWEST FROM THE GREAT LAKES...AND WHILE THE FRONT IS
SOMEWHAT STRONG WITH REGARDS TO THE TEMPERATURE
GRADIENT...FORCING AND MOISTURE OVER THE CWA APPEAR TO BE
MARGINAL. THE BETTER FORCING APPEARS TO SET UP OVER THE NORTHERN
HALF (ESPECIALLY THE NORTHEASTERN QUARTER) OF THE CWA...WHERE THE
ORIENTATION OF THE FRONT IS A BIT MORE PERPENDICULAR TO ITS MOTION
VECTOR. IN ADDITION...TEMPERATURES AHEAD OF THE FRONT WILL GET
WARM ENOUGH TO SUPPORT A BIT OF MIXING WITH RAIN IN THE FAR SOUTH
DURING THE AFTERNOON. THUS...THE HIGHEST SNOWFALL TOTALS WILL BE
FORECAST IN THE NORTH...WITH AROUND AN INCH EXPECTED NEAR THE
NORTHERN BORDER. LITTLE TO NO ACCUMULATION IS EXPECTED IN THE FAR
SOUTH.
WHILE LINGERING LOW-LEVEL MOISTURE MAY NOT ALLOW FOR TOTAL
CLEARING ON THURSDAY NIGHT...THE CENTER OF THE HIGH BEHIND THE
FRONT WILL BE OVER THE REGION. TEMPERATURES IN THE TEENS
(ESPECIALLY IN THE NORTHERN HALF OF THE CWA) WILL BE A NEAR
CERTAINTY. IF CLEARING DEVELOPS IN SOME PLACES...THESE NUMBERS
COULD BE EVEN A LITTLE BIT HIGH.
IT IS BEGINNING TO APPEAR THAT THE WEATHER DISTURBANCE FOR FRIDAY
NIGHT AND EARLY SATURDAY WILL HAVE A RESPECTABLE IMPACT FOR THE
AREA...INCLUDING A MIX OF PRECIPITATION TYPES. HOWEVER...THERE ARE
STILL SIGNIFICANT DIFFERENCES IN TIMING AND PLACEMENT...REGARDING
BOTH THE MID-LEVEL SHORTWAVE AND THE DEVELOPING SURFACE LOW. THESE
DIFFERENCES PRECLUDE MAKING AN EXTREMELY SPECIFIC OR DETERMINISTIC
FORECAST. HOWEVER...WHAT HAS BECOME CLEAR IS THAT THERE WILL BE A
ZONE OF A RELATIVELY DEEP LAYER (100 MB OR A FEW THOUSAND FEET AT
LEAST) OF TEMPERATURES ABOVE FREEZING ABOVE THE SURFACE...WITH
TEMPS IN THE LOWER 30S TO UPPER 20S AT THE GROUND. AT THIS
TIME...THE ECMWF IS FORECASTING A STRONGER SURFACE LOW...WARMER
TEMPERATURES...AND A TIMING DIFFERENCE (FASTER) OF ABOUT SIX HOURS
AS COMPARED TO THE GFS. WITH VARYING DEGREES OF AGREEMENT (OR
DISAGREEMENT) BETWEEN SOME OF THE OTHER MODELS...WILL KEEP THINGS
RATHER GENERAL AND PROBABILISTIC IN THE FORECAST FOR NOW.
IN MAKING THE FIRST ATTEMPT TO INCLUDE THESE MIXED PRECIPITATION
ELEMENTS IN THE GRIDS...A TRANSITION ZONE BETWEEN ALL-RAIN AND
ALL-SNOW ELEMENTS HAS BEEN INCLUDED ROUGHLY COINCIDENT WITH
SURFACE TEMPS BETWEEN 28 AND 32 DEGREES. THUS...THE BEST
INDICATIONS AT THIS TIME ARE THAT THE MIX ZONE WILL CUT THROUGH
THE CENTER OF THE CWA...WITH ALL RAIN POSSIBLE SOUTH OF THE OHIO
RIVER AND ALL SNOW POSSIBLE IN THE FAR NORTHWEST. THE EXACT
PLACEMENT AND TIMING (AND EVENTUALLY...MAGNITUDE) OF THE
TRANSITIONAL ZONE WILL BE ABLE TO BE REFINED ONCE MODEL AGREEMENT
IMPROVES. THE SNOW NORTH OF THE TRANSITION ZONE WILL LIKELY BE OF
THE ACCUMULATING NATURE.
AS THE PRECIPITATION PULLS OUT OF THE REGION...THE WARM AIR ALOFT
WILL DEPART BEFORE ALL OF THE SUB-FREEZING AIR AT THE SURFACE IS
IN PLACE. THUS...THE TRANSITION ON THE BACK EDGE OF THE SYSTEM
SHOULD JUST BE RAIN TO SNOW.
NON-DIURNAL TEMPERATURES WERE RUN THROUGH SATURDAY AFTERNOON...WITH
ADVECTION DOMINATING THE RADIATIONAL COMPONENTS OF THE TEMPERATURE
FORECAST. THIS WAS MOST NECESSARY FOR THURSDAY...AND FRIDAY NIGHT
INTO SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
A ZONAL FLOW REGIME SUNDAY AND MONDAY WILL FEATURE A LACK OF
WEATHER PRODUCING SYSTEMS...SO KEPT POPS BELOW THE 25 PERCENT
THRESHOLD FOR MENTION OF PRECIP IN THE 3 TO 7 DAY FORECAST. DURING
THIS PERIOD...IT APPEARS THAT PRECIPITATION ASSOCIATED WITH A
COUPLE OF SHORT WAVES WILL STAY OUT OF THE ILN AREA. SHOWERS ALONG
THE NEXT FRONTAL ZONE MAY ENTER THE AREA FROM THE WEST LATE ON
TUESDAY.
TEMPERATURES ARE FORECAST TO BE BELOW NORMAL ON FRIDAY...WITH HIGHS
AVERAGING ABOUT 30. READINGS ARE FORECAST TO INCREASE
THEREAFTER...REACHING AROUND 50 BY TUESDAY. THESE MILD FORECAST
TEMPS ARE ABOVE THE GFS BUT BELOW THE WARM ECMWF WHICH SUGGESTS
HIGHS IN THE 60S SUNDAY THROUGH TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TODAY. CAA INDUCED
STRATOCUMULUS CLOUDS WILL BE SLOW TO ERODE...BUT SHOULD SCATTER
OUT BETWEEN 18Z AND 00Z. SOME BRIEF PERIODS OF MVFR CIGS AND
SCATTERED FLURRIES CAN BE EXPECTED EARLY ON.
FOR TONIGHT...HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST
TONIGHT AS A COLD FRONT DROPS SOUTHEAST INTO THE WESTERN GREAT
LAKES AND MID MISSISSIPPI RIVER VALLEY. MID AND HIGH LVL
CLOUDINESS WILL INCREASE ACROSS THE REGION. WINDS WILL BECOME
SOUTHERLY.
OUTLOOK...MVFR CEILINGS AND MVFR/IFR VISIBILITIES POSSIBLE ON
THURSDAY. MVFR/IFR CEILINGS AND VISIBILITIES POSSIBLE FRIDAY
NIGHT AND SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
417 AM EST WED JAN 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTROL THE WEATHER OVER THE OHIO VALLEY
TODAY...WITH SNOW SHOWERS TAPERING OFF BY LATE MORNING. LOW PRESSURE
WILL MOVE THROUGH THE GREAT LAKES ON THURSDAY...WITH A COLD FRONT
PROVIDING A CHANCE OF SHOW FOR THE REGION. ANOTHER WEATHER
DISTURBANCE WILL BRING MIXED PRECIPITATION FOR FRIDAY NIGHT AND
SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW SHOWERS AND FLURRIES HAVE PERSISTED OVER THE REGION A BIT
LONGER THAN PREVIOUSLY ANTICIPATED...AND CERTAINLY LONGER THAN
DEPICTED BY THE PRIMARY SUITE OF MODELS. THE HRRR WAS HELPFUL IN
DETERMINING THE EXTENT OF THE REMAINING SNOWFALL...AND ITS GRADUAL
DIMINISHING OVER THE COURSE OF THE MORNING.
SKIES WILL GRADUALLY CLEAR FROM WEST TO EAST...AS HIGH PRESSURE
MOVES INTO THE AREA AND GETS STRETCHED OUT SW-TO-NE. THE COOL AIR
MASS WILL KEEP TEMPERATURES FROM RISING SIGNIFICANTLY...WITH HIGHS
IN THE FORECAST ABOUT 5 DEGREES BELOW CLIMATOLOGY. WINDS WILL
SHIFT FROM NW (COLD ADVECTION) TO SW (WARM ADVECTION) LATE IN THE
DAY...BUT NOT SOON ENOUGH TO RAISE TEMPERATURES IN THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERE ARE TWO MAIN CONCERNS FOR THE SHORT TERM OF THE FORECAST.
THE FIRST IS A COLD FRONT WITH SNOW ON THURSDAY...AND THE SECOND
IS A SYSTEM BRINGING MIXED PRECIPITATION ON FRIDAY NIGHT INTO
SATURDAY.
WARM ADVECTION WILL BEGIN TONIGHT ON SOUTHWESTERLY WINDS...AS
SURFACE HIGH PRESSURE MOVES EAST OF THE REGION. A COLD FRONT WILL
MOVE SOUTHWEST FROM THE GREAT LAKES...AND WHILE THE FRONT IS
SOMEWHAT STRONG WITH REGARDS TO THE TEMPERATURE
GRADIENT...FORCING AND MOISTURE OVER THE CWA APPEAR TO BE
MARGINAL. THE BETTER FORCING APPEARS TO SET UP OVER THE NORTHERN
HALF (ESPECIALLY THE NORTHEASTERN QUARTER) OF THE CWA...WHERE THE
ORIENTATION OF THE FRONT IS A BIT MORE PERPENDICULAR TO ITS MOTION
VECTOR. IN ADDITION...TEMPERATURES AHEAD OF THE FRONT WILL GET
WARM ENOUGH TO SUPPORT A BIT OF MIXING WITH RAIN IN THE FAR SOUTH
DURING THE AFTERNOON. THUS...THE HIGHEST SNOWFALL TOTALS WILL BE
FORECAST IN THE NORTH...WITH AROUND AN INCH EXPECTED NEAR THE
NORTHERN BORDER. LITTLE TO NO ACCUMULATION IS EXPECTED IN THE FAR
SOUTH.
WHILE LINGERING LOW-LEVEL MOISTURE MAY NOT ALLOW FOR TOTAL
CLEARING ON THURSDAY NIGHT...THE CENTER OF THE HIGH BEHIND THE
FRONT WILL BE OVER THE REGION. TEMPERATURES IN THE TEENS
(ESPECIALLY IN THE NORTHERN HALF OF THE CWA) WILL BE A NEAR
CERTAINTY. IF CLEARING DEVELOPS IN SOME PLACES...THESE NUMBERS
COULD BE EVEN A LITTLE BIT HIGH.
IT IS BEGINNING TO APPEAR THAT THE WEATHER DISTURBANCE FOR FRIDAY
NIGHT AND EARLY SATURDAY WILL HAVE A RESPECTABLE IMPACT FOR THE
AREA...INCLUDING A MIX OF PRECIPITATION TYPES. HOWEVER...THERE ARE
STILL SIGNIFICANT DIFFERENCES IN TIMING AND PLACEMENT...REGARDING
BOTH THE MID-LEVEL SHORTWAVE AND THE DEVELOPING SURFACE LOW. THESE
DIFFERENCES PRECLUDE MAKING AN EXTREMELY SPECIFIC OR DETERMINISTIC
FORECAST. HOWEVER...WHAT HAS BECOME CLEAR IS THAT THERE WILL BE A
ZONE OF A RELATIVELY DEEP LAYER (100 MB OR A FEW THOUSAND FEET AT
LEAST) OF TEMPERATURES ABOVE FREEZING ABOVE THE SURFACE...WITH
TEMPS IN THE LOWER 30S TO UPPER 20S AT THE GROUND. AT THIS
TIME...THE ECMWF IS FORECASTING A STRONGER SURFACE LOW...WARMER
TEMPERATURES...AND A TIMING DIFFERENCE (FASTER) OF ABOUT SIX HOURS
AS COMPARED TO THE GFS. WITH VARYING DEGREES OF AGREEMENT (OR
DISAGREEMENT) BETWEEN SOME OF THE OTHER MODELS...WILL KEEP THINGS
RATHER GENERAL AND PROBABILISTIC IN THE FORECAST FOR NOW.
IN MAKING THE FIRST ATTEMPT TO INCLUDE THESE MIXED PRECIPITATION
ELEMENTS IN THE GRIDS...A TRANSITION ZONE BETWEEN ALL-RAIN AND
ALL-SNOW ELEMENTS HAS BEEN INCLUDED ROUGHLY COINCIDENT WITH
SURFACE TEMPS BETWEEN 28 AND 32 DEGREES. THUS...THE BEST
INDICATIONS AT THIS TIME ARE THAT THE MIX ZONE WILL CUT THROUGH
THE CENTER OF THE CWA...WITH ALL RAIN POSSIBLE SOUTH OF THE OHIO
RIVER AND ALL SNOW POSSIBLE IN THE FAR NORTHWEST. THE EXACT
PLACEMENT AND TIMING (AND EVENTUALLY...MAGNITUDE) OF THE
TRANSITIONAL ZONE WILL BE ABLE TO BE REFINED ONCE MODEL AGREEMENT
IMPROVES. THE SNOW NORTH OF THE TRANSITION ZONE WILL LIKELY BE OF
THE ACCUMULATING NATURE.
AS THE PRECIPITATION PULLS OUT OF THE REGION...THE WARM AIR ALOFT
WILL DEPART BEFORE ALL OF THE SUB-FREEZING AIR AT THE SURFACE IS
IN PLACE. THUS...THE TRANSITION ON THE BACK EDGE OF THE SYSTEM
SHOULD JUST BE RAIN TO SNOW.
NON-DIURNAL TEMPERATURES WERE RUN THROUGH SATURDAY AFTERNOON...WITH
ADVECTION DOMINATING THE RADIATIONAL COMPONENTS OF THE TEMPERATURE
FORECAST. THIS WAS MOST NECESSARY FOR THURSDAY...AND FRIDAY NIGHT
INTO SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
A ZONAL FLOW REGIME SUNDAY AND MONDAY WILL FEATURE A LACK OF
WEATHER PRODUCING SYSTEMS...SO KEPT POPS BELOW THE 25 PERCENT
THRESHOLD FOR MENTION OF PRECIP IN THE 3 TO 7 DAY FORECAST. DURING
THIS PERIOD...IT APPEARS THAT PRECIPITATION ASSOCIATED WITH A
COUPLE OF SHORT WAVES WILL STAY OUT OF THE ILN AREA. SHOWERS ALONG
THE NEXT FRONTAL ZONE MAY ENTER THE AREA FROM THE WEST LATE ON
TUESDAY.
TEMPERATURES ARE FORECAST TO BE BELOW NORMAL ON FRIDAY...WITH HIGHS
AVERAGING ABOUT 30. READINGS ARE FORECAST TO INCREASE
THEREAFTER...REACHING AROUND 50 BY TUESDAY. THESE MILD FORECAST
TEMPS ARE ABOVE THE GFS BUT BELOW THE WARM ECMWF WHICH SUGGESTS
HIGHS IN THE 60S SUNDAY THROUGH TUESDAY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
MID LEVEL DISTURBANCE WILL TRACK ACROSS THE REGION THROUGH 12Z.
THIS FEATURE COMBINED WITH CAA CROSSING OVER THE RELATIVELY WARM
WATERS OF THE GREAT LAKES WILL RESULT IN SOME FLURRIES AND
EMBEDDED SNOW SHOWERS. CONDITIONS SHOULD STAY MVFR FOR THE MOST
PART...BUT A BRIEF PERIOD OF IFR VSBYS CAN NOT BE TOTALLY RULED
OUT IN HEAVIER SNOW SHOWERS. AFTER THE DISTURBANCE DEPARTS TO THE
EAST...LOW LEVEL FLOW WILL BECOME ANTICYCLONIC AS SURFACE HIGH
PRESSURE BUILDS INTO THE OHIO VALLEY. STRATOCUMULUS CLOUDS WILL
GRADUALLY SCATTER FROM WEST TO EAST BETWEEN 12Z AND 18Z.
HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST TONIGHT AS A COLD
FRONT DROPS SOUTHEAST INTO THE WESTERN GREAT LAKES AND MID
MISSISSIPPI RIVER VALLEY.
OUTLOOK...MVFR CIGS AND MVFR/IFR VSBYS POSSIBLE ON THURSDAY. MVFR/IFR
CIGS AND VSBYS POSSIBLE FRIDAY NIGHT AND SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS PORTLAND OR
1046 PM PST TUE JAN 17 2012
.SYNOPSIS...A STRONG SURFACE LOW WILL MOVE TO NEAR ASTORIA BY
WEDNESDAY AFTERNOON BEFORE WEAKENING AND DRIFTING NORTH. THIS WILL
BRING VERY STRONG GUST WINDS TO THE COAST...THE CASCADES AND TO A
SMALLER EXTENT THE WILLAMETTE VALLEY LATE TONIGHT AND WEDNESDAY.
SEVERAL MORE STORM SYSTEMS WILL BATTER THE FORECAST AREA THURSDAY
THROUGH EARLY NEXT WEEK.
&&
...URGENT NOTICE OF UPDATE...
THIS IS JUST A VERY QUICK UPDATE TO LET EVERYONE KNOW WE ARE IN THE
PROCESS OF UPGRADING TO A WINTER STORM WARNING FOR THE PORTLAND AND
VANCOUVER METRO AREA...AND OUR LOWLANDS TO THE NORTH. THE WARNING
WILL BE ISSUED SHORTLY...AND THE APPROPRIATE ADJUSTMENTS WILL BE
MADE FOR THE FORECASTS.
SNOW HAS ALREADY ACCUMULATED UP TO AROUND AN INCH HERE AT THE OFFICE
IN NE PORTLAND AND LOCALLY UP TO 3 INCHES IN PARTS OF GRESHAM...
SEVERAL INCHES MORE ARE EXPECTED BEFORE CHANGEOVER TO RAIN OCCURS
WEDNESDAY MORNING. MUCH LESSER ACCUMULATIONS THUS FAR ON THE WEST
SIDE...BUT THEY ARE LIKELY TO START ACCUMULATING SOON. THIS IS
SHAPING UP TO BE A WIDESPREAD SIGNIFICANT WINTER WEATHER EVENT FOR
THE PORTLAND AND VANCOUVER METRO AREA.
.SHORT TERM...STILL QUITE A BIT OF UNCERTAINTY AS TO THE EXTENT OF
FINER DETAILS REGARDING THE POTENTIAL SNOW EVENT LATE TONIGHT.
STATING THE OBVIOUS...SNOWFALL TONIGHT WILL BE HIGHLY DEPENDENT ON
ELEVATION AND HOW FAR NORTH ONE GETS. A MAJOR DRAWBACK PREVENTING
THIS FROM BEING A WIDESPREAD MAJOR SNOW EVENT IS THE LACK OF A COLD
AIR SOURCE. GRANTED...COLD AIR HAS WORKED ITS WAY INTO NORTHERN AND
CENTRAL WASHINGTON...BUT IT IS HAVING A HARD TIME MIGRATING SOUTH.
03Z TEMPS IN THE COLUMBIA BASIN WERE IN THE 30S...WHICH IS CERTAINLY
NOT FAVORABLE FOR DRAWING THE NEEDED COLD AIR THROUGH THE GORGE INTO
THE PORTLAND/VANCOUVER METRO AREA.
THE 00Z KSLE SOUNDING SHOWED ABOUT -4C AT 850 MB...WHICH WAS CLOSER
TO THE GFS FORECAST THAN THE NAM. ACTUALLY...THE GFS WAS A TOUCH TOO
WARM AND THE NAM A TAD COOL. RAPID UPDATE CYCLE (RUC) SOUNDING VIA
BUFKIT FOR KPDX INDICATES SNOW FROM ABOUT 07Z-16Z. THE RUC SOUNDING
FOR KSLE SHOWS ALL RAIN...WITH SNOW DOWN TO ABOUT 500 FEET. THUS...AS
HAS BEEN SAID THE PAST COUPLE OF DAYS...THERE IS A FINE LINE BETWEEN
THOSE THAT GET SOME SNOW AND THOSE THAT DO NOT. LOOK FOR OFFSHORE
LOW-LEVEL FLOW TO DEVELOP IN THE GORGE AROUND MIDNIGHT AND GET A
LITTLE STRONGER THROUGH THE LATE-NIGHT HOURS. NAM HAS THE SURFACE LOW
HEADED TOWARD ABOUT KTMK AT 15Z...BUT IT ENDS UP AT KAST
18Z-21Z...SIMILAR TO PAST COUPLE RUNS. STILL THINK THE OFFSHORE FLOW
WILL PULL JUST ENOUGH COLD AIR TO GIVE A PERIOD OF SNOW TO THE METRO
AREA...ESPECIALLY ABOVE 500 FEET. THE 12KM MM5-NAM SHOWS ABOUT 1 TO 4
INCHES FOR KPDX BETWEEN 09Z AND 15Z...THEN EVERYTHING TURNS TO RAIN.
THE SAME MODEL SHOWS 1-2 INCH/HR...LOCALLY UP TO 3 IN/HR...SNOWFALL
RATES IN THE CASCADES. THE SKI AREAS HAVE ALREADY PICKED UP AROUND 2
FEET SINCE MON AFTERNOON (SEE PNS AND LSR). POINTS SOUTH OF SALEM
WILL LIKELY SEE LITTLE TO NO SNOW. THE CENTRAL AND SOUTH WILLAMETTE
VALLEY ABOVE 500 TO 1000 FEET WILL GET SOME OVERNIGHT...BUT IT WILL
NOT LAST LONG.
LATEST AVAILABLE MODELS MAINTAIN AN ABRUPT SHIFT TO STRONG SOUTH
LOW-LEVEL FLOW WED. THE CURRENT WIND WARNINGS REMAIN ON TRACK.
INTERESTING TO NOTE THAT THE RUC SOUNDING FOR KSLE VALID 17Z HAS SW
WIND OF 50 KTS AT 2100 FT...AND UP TO 80 KT AT 5000 FT. WOULD NOT BE
SURPRISED TO SEE 100 MPH AT THE 7000 FT TIMBERLINE LODGE SENSOR.
ELSEWHERE...SOUTH WIND WILL BEGIN TO STRENGTHEN ALONG THE CENTRAL
COAST AROUND MIDNIGHT...THEN SPREAD NORTH OVERNIGHT AND EARLY WED
MORNING. STILL LOOKS LIKE HIGH-END WIND ADVISORY CONDITIONS FOR THE
WILLAMETTE VALLEY WED...ESPECIALLY SOUTH OF SALEM. THE LATEST MET
GUIDANCE SHOWS SUSTAINED WIND OF 28 KT FOR KSLE AT 18Z.
ANOTHER CONCERN WILL BE THE QPF. AMSU TOTAL PRECIPITABLE WATER VALUES
WERE AROUND 2.0 INCHES OUT AT 40N/144W. LATEST GFS HAS 6-HR RAINFALL
UP TO AN INCH ALONG THE COAST 06Z-12Z WED AND UP TO 2 INCHES 12Z-18Z.
COMBINE THAT WITH 60-75 KT 850 MB SWLY FLOW...THE OROGRAPHIC
COMPONENT SHOULD BE TREMENDOUS. BY 00Z THU THE CASCADE SNOW LEVELS
WILL BE UP ABOVE 3500 FEET...EXCEPT FOR THE S WA CASCADES AND EXTREME
N OREGON CASCADES CLOSEST TO THE GORGE. BY 06Z THU SNOW LEVELS GO UP
TO 4000 FEET NEAR MT. HOOD TO OVER 7000 FEET IN THE LANE COUNTY
CASCADES. THE NAM SHOWS ANOTHER SYSTEM DEVELOPING ALONG THE LEFT-OVER
BAROCLINIC ZONE OVER SWRN OREGON AND NRN CA THU WILL IMPACT THE
FORECAST AREA THU. WEISHAAR
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SEVERAL
SIGNIFICANT STORMS WILL TRACK OVER THE PACIFIC NORTHWEST THROUGH MUCH
FOR THE EXTENDED PERIOD. SNOW LEVELS REMAIN WELL ABOVE 3000 FEET WITH
THE SYSTEM THE MOVES THROUGH LATE FRIDAY...MAINTAINING HEAVY RAIN
ACROSS THE FORECAST AREA INTO SATURDAY. THE NEXT SYSTEM APPROACHES
LATE SATURDAY... BRINGING A THREAT FOR STRONG WINDS ALONG THE COAST
SATURDAY NIGHT INTO SUNDAY. SNOW LEVELS ARE EXPECTED TO DROP WITH
THIS SYSTEM...SO AREAS ABOVE ABOUT 1500 TO 2000 FEET CAN EXPECT SNOW
THROUGH SUNDAY. MODERATE PRECIPITATION CONTINUES INTO EARLY NEXT WEEK
UNDER A WESTERLY FLOW PATTERN...WITH ANOTHER POSSIBLY STRONG SYSTEM
BY MONDAY NIGHT. WILL CONTINUE TO MAINTAIN ABUNDANT PRECIPITATION
AMOUNTS AND COOLER TEMPERATURES THROUGH NEXT WEEKEND.
WILL BE KEEPING A CLOSE EYE ON ANY HYDRO ISSUES THAT WILL LIKELY
APPEAR BY THURSDAY AND FRIDAY AS RISING RIVER LEVELS ARE A CONCERN.
BROWN
&&
.AVIATION...STEADY LIGHT TO MODERATE RAIN WILL CONTINUE THIS EVENING
WITH WIDESPREAD MVFR CONDITIONS AND TRENDING TO IFR AS
PRECIPITATION PICKS UP LATER TONIGHT. LOCATIONS NORTH AND WEST OF
KPDX WILL SEE SNOW MIXED IN...AS WELL AS IN THE COLUMBIA RIVER
GORGE. BUT SOUTHERLY WINDS HAVE NOW EASED AROUND PORTLAND AND
TROUTDALE...AND NOW WE ARE SEEING SNOW AT KTTD AND RAIN/SNOW AT
KPDX. FEEL PRETTY CONFIDENT THAT VALLEY LOCATIONS SOUTH OF AURORA OR
SO WILL REMAIN ALL RAIN TONIGHT. THE POTENTIAL FOR SNOW ARE THE VERY
STRONG WINDS EXPECTED AT THE COAST AND POTENTIALLY INLAND AS
WELL...THOUGH THE INLAND WINDS ARE LESS CERTAIN AT THIS TIME.
PRECIPITATION TRANSITIONS TO ALL MODERATE TO HEAVY RAIN DURING THE
DAY BEFORE EASING TOMORROW NIGHT...AND EXPECT ALL LOCATIONS EXCEPT
THE GORGE TO BE RAIN BY MIDDAY. EXPECT A MIX OF MVFR AND MORE LIKELY
IFR TO CONTINUE. OF ADDITIONAL CONCERN ARE THE STRONG SOUTHERLY
WINDS TOMORROW THAT WILL BE FOUND NOT ONLY AT THE COAST...BUT EXPECT
BREEZY TO WINDY CONDITIONS IN THE VALLEY...WITH THE STRONGEST VALLEY
WINDS FROM SALEM SOUTH.
KPDX AND APPROACHES...EXPECT A RAIN/SNOW MIX TO CONTINUE THIS
EVENING...AND THEREFORE VARYING CONDITIONS FROM MVFR TO
IFR...BEFORE HEAVY PRECIPITATION ARRIVES OVERNIGHT WITH
PREDOMINANT IFR REGARDLESS OF PRECIP TYPE. IT IS POSSIBLE TO SEE
ACCUMULATING SNOW AT THE TERMINAL MAINLY OVERNIGHT. LIKE MOST
STORMS IT WILL BE SPLITTING HAIRS TO DETERMINE IF IT WILL STICK AT
KPDX OR NOT. LATEST GUIDANCE HAS NOT CHANGED MUCH...BUT WE WILL
CONTINUE TO WATCH AS TROUTDALE IS NOW SEEING ALL SNOW AND FALLING
TEMPERATURES. IF COLD AIR LINGERS LONG ENOUGH THE WORST CASE
SCENARIO WOULD BE 4 PLUS INCHES WHILE MOST GUIDANCE POINTS TO 1 TO
3 INCHES OF VERY WET SLUSHY ACCUMULATION IF ANY BEFORE A CHANGE OVER
TO RAIN. THAT SAID...MOST GUIDANCE IS TOO WARM ON SFC TEMPS AND
DEWPOINTS AT THE MOMENT...AND HAVE INCREASED CONCERNS ON STICKING
SNOW...GIVEN HEAVIER PRECIP RATES OVERNIGHT. SNOW WILL BE FALLING
HARD AT ELEVATIONS ABOVE 500 FT.
CONFIDENCE LOW ON SPECIFIC SOUTHERLY WINDS TOMORROW...BUT EXPECT
BREEZY CROSS RUNWAY WINDS. KMD/WOLFE
&&
.MARINE...AFTER A RELATIVE LULL IN COASTAL WATERS WINDS THIS
EVENING...EXPECT
WINDS AND SEAS TO RAPIDLY INCREASE LATE TONIGHT AND TOMORROW NAM
AND GFS BOUNDARY LAYER WIND SPEED BOTH REACH 60-70 KT FOR A SHORT
TIME IN THE MORNING...AND WITH 925-850 MB WINDS IN THE 80+ KNOT
RANGE. SOLID STORM FORCE WINDS WITH A PERIOD OF HURRICANE FORCE
WINDS STILL ON TRACK.
STARTING WEDNESDAY MORNING MORNING A VERY STRONG SYSTEM ARRIVES AND
BRINGS WIND GUSTS IN EXCESS OF 65 KTS TO A GOOD PORTION OF THE
CENTRAL OREGON COASTAL WATERS...SO HAVE ISSUED A HURRICANE FORCE
WIND WARNING FROM 4 AM UNTIL 1 PM PST FOR THE CENTRAL COASTAL
WATERS. THE CENTER OF LOW PRES LOOKS TO PASS RIGHT OVER ASTORIA.
THEREFORE THE NORTHERN WATERS LOOK TO ESCAPE THE STRONGEST WINDS
BUT WINDS WILL LIKELY BE IN THE STRONG STORM FORCE GUST ARENA
DUE TO THE LOW PLACEMENT...THERE MAY BE AREAS WHERE WINDS QUICKLY
SWITCH FROM STRONG OFFSHORE TO VERY STRONG SOUTHWEST. THIS IS AN
EXTREMELY DANGEROUS STORM. PLEASE TAKE NECESSARY PRECAUTIONS!
WILL MAINTAIN A HIGH SURF ADVISORY FOR THE CENTRAL OREGON COAST
WEDNESDAY AND THE COASTAL FLOOD ADVISORY FOR TIDAL OVERFLOW FOR
BOTH THE NORTH AND CENTRAL OREGON COAST. HIGH TIDE IN THE EARLY
MORNING AND STRONG TIDAL ANOMALY EXPECTED GIVEN THE STORM
STRENGTH. S/SW FACING LOCALES WILL EXPERIENCE THE ROUGHEST SURF
CONDITIONS. CONFIDENCE IS LOWER FOR THE NORTH OREGON COAST WITH
LOWER FORECAST SEAS WITH SHORT LOW PERIODS...BUT AGAIN NOT OUT OF
THE QUESTION EITHER AS WE GET CLOSER TO THE EVENT AND SEE HOW
QUICKLY SEAS BUILD. KMD/WOLFE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING UNTIL 6 PM PST WEDNESDAY FOR NORTHERN
OREGON CASCADE FOOTHILLS-NORTHERN OREGON CASCADES-UPPER
HOOD RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE.
WINTER STORM WARNING UNTIL 3 PM PST WEDNESDAY FOR CASCADE
FOOTHILLS IN LANE COUNTY-CASCADES IN LANE COUNTY.
WINTER WEATHER ADVISORY UNTIL 1 PM PST WEDNESDAY FOR GREATER
PORTLAND METRO AREA.
WIND ADVISORY FROM NOON TO 6 PM PST WEDNESDAY FOR GREATER
PORTLAND METRO AREA.
WINTER WEATHER ADVISORY UNTIL 10 AM PST WEDNESDAY FOR CENTRAL
WILLAMETTE VALLEY-LOWER COLUMBIA-NORTH OREGON COAST-SOUTH
WILLAMETTE VALLEY.
HIGH WIND WARNING FROM 11 PM THIS EVENING TO 4 PM PST WEDNESDAY
FOR CENTRAL COAST RANGE OF WESTERN OREGON-CENTRAL OREGON
COAST.
WINTER STORM WARNING UNTIL 6 AM PST WEDNESDAY FOR CENTRAL COAST
RANGE OF WESTERN OREGON.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM PST WEDNESDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
HIGH SURF ADVISORY FROM 4 AM TO 7 PM PST WEDNESDAY FOR CENTRAL
OREGON COAST.
WINTER STORM WARNING UNTIL NOON PST WEDNESDAY FOR COAST RANGE
OF NORTHWEST OREGON.
WIND ADVISORY FROM 6 AM TO 4 PM PST WEDNESDAY FOR CENTRAL
WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY.
HIGH WIND WARNING FROM 1 AM TO 4 PM PST WEDNESDAY FOR COAST
RANGE OF NORTHWEST OREGON-NORTH OREGON COAST.
WA...WINTER STORM WARNING UNTIL 6 PM PST WEDNESDAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS-SOUTH WASHINGTON CASCADES-
WESTERN COLUMBIA RIVER GORGE.
WINTER WEATHER ADVISORY UNTIL 1 PM PST WEDNESDAY FOR GREATER
VANCOUVER AREA.
WIND ADVISORY FROM NOON TO 6 PM PST WEDNESDAY FOR GREATER
VANCOUVER AREA.
WINTER WEATHER ADVISORY UNTIL 10 AM PST WEDNESDAY FOR I-5
CORRIDOR IN COWLITZ COUNTY-SOUTH WASHINGTON COAST.
WINTER STORM WARNING UNTIL NOON PST WEDNESDAY FOR WILLAPA HILLS.
PZ...STORM WARNING FROM 1 AM TO 4 PM PST WEDNESDAY FOR COASTAL
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10
NM-WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM
10 TO 60 NM.
STORM WARNING FROM 1 AM TO 4 AM PST WEDNESDAY FOR COASTAL
WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-WATERS FROM
CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
HURRICANE FORCE WIND WARNING FROM 4 AM TO 1 PM PST WEDNESDAY
FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH WED
AFTERNOON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
851 PM PST TUE JAN 17 2012
.SYNOPSIS...A STRONG SURFACE LOW WILL MOVE TO NEAR ASTORIA BY
WEDNESDAY AFTERNOON BEFORE WEAKENING AND DRIFTING NORTH. THIS WILL
BRING VERY STRONG GUST WINDS TO THE COAST...THE CASCADES AND TO A
SMALLER EXTENT THE WILLAMETTE VALLEY LATE TONIGHT AND WEDNESDAY.
SEVERAL MORE STORM SYSTEMS WILL BATTER THE FORECAST AREA THURSDAY
THROUGH EARLY NEXT WEEK.
&&
.SHORT TERM...STILL QUITE A BIT OF UNCERTAINTY AS TO THE EXTENT OF
FINER DETAILS REGARDING THE POTENTIAL SNOW EVENT LATE TONIGHT.
STATING THE OBVIOUS...SNOWFALL TONIGHT WILL BE HIGHLY DEPENDENT ON
ELEVATION AND HOW FAR NORTH ONE GETS. A MAJOR DRAWBACK PREVENTING
THIS FROM BEING A WIDESPREAD MAJOR SNOW EVENT IS THE LACK OF A COLD
AIR SOURCE. GRANTED...COLD AIR HAS WORKED ITS WAY INTO NORTHERN AND
CENTRAL WASHINGTON...BUT IT IS HAVING A HARD TIME MIGRATING SOUTH.
03Z TEMPS IN THE COLUMBIA BASIN WERE IN THE 30S...WHICH IS CERTAINLY
NOT FAVORABLE FOR DRAWING THE NEEDED COLD AIR THROUGH THE GORGE INTO
THE PORTLAND/VANCOUVER METRO AREA.
THE 00Z KSLE SOUNDING SHOWED ABOUT -4C AT 850 MB...WHICH WAS CLOSER
TO THE GFS FORECAST THAN THE NAM. ACTUALLY...THE GFS WAS A TOUCH TOO
WARM AND THE NAM A TAD COOL. RAPID UPDATE CYCLE (RUC) SOUNDING VIA
BUFKIT FOR KPDX INDICATES SNOW FROM ABOUT 07Z-16Z. THE RUC SOUNDING
FOR KSLE SHOWS ALL RAIN...WITH SNOW DOWN TO ABOUT 500 FEET. THUS...AS
HAS BEEN SAID THE PAST COUPLE OF DAYS...THERE IS A FINE LINE BETWEEN
THOSE THAT GET SOME SNOW AND THOSE THAT DO NOT. LOOK FOR OFFSHORE
LOW-LEVEL FLOW TO DEVELOP IN THE GORGE AROUND MIDNIGHT AND GET A
LITTLE STRONGER THROUGH THE LATE-NIGHT HOURS. NAM HAS THE SURFACE LOW
HEADED TOWARD ABOUT KTMK AT 15Z...BUT IT ENDS UP AT KAST
18Z-21Z...SIMILAR TO PAST COUPLE RUNS. STILL THINK THE OFFSHORE FLOW
WILL PULL JUST ENOUGH COLD AIR TO GIVE A PERIOD OF SNOW TO THE METRO
AREA...ESPECIALLY ABOVE 500 FEET. THE 12KM MM5-NAM SHOWS ABOUT 1 TO 4
INCHES FOR KPDX BETWEEN 09Z AND 15Z...THEN EVERYTHING TURNS TO RAIN.
THE SAME MODEL SHOWS 1-2 INCH/HR...LOCALLY UP TO 3 IN/HR...SNOWFALL
RATES IN THE CASCADES. THE SKI AREAS HAVE ALREADY PICKED UP AROUND 2
FEET SINCE MON AFTERNOON (SEE PNS AND LSR). POINTS SOUTH OF SALEM
WILL LIKELY SEE LITTLE TO NO SNOW. THE CENTRAL AND SOUTH WILLAMETTE
VALLEY ABOVE 500 TO 1000 FEET WILL GET SOME OVERNIGHT...BUT IT WILL
NOT LAST LONG.
LATEST AVAILABLE MODELS MAINTAIN AN ABRUPT SHIFT TO STRONG SOUTH
LOW-LEVEL FLOW WED. THE CURRENT WIND WARNINGS REMAIN ON TRACK.
INTERESTING TO NOTE THAT THE RUC SOUNDING FOR KSLE VALID 17Z HAS SW
WIND OF 50 KTS AT 2100 FT...AND UP TO 80 KT AT 5000 FT. WOULD NOT BE
SURPRISED TO SEE 100 MPH AT THE 7000 FT TIMBERLINE LODGE SENSOR.
ELSEWHERE...SOUTH WIND WILL BEGIN TO STRENGTHEN ALONG THE CENTRAL
COAST AROUND MIDNIGHT...THEN SPREAD NORTH OVERNIGHT AND EARLY WED
MORNING. STILL LOOKS LIKE HIGH-END WIND ADVISORY CONDITIONS FOR THE
WILLAMETTE VALLEY WED...ESPECIALLY SOUTH OF SALEM. THE LATEST MET
GUIDANCE SHOWS SUSTAINED WIND OF 28 KT FOR KSLE AT 18Z.
ANOTHER CONCERN WILL BE THE QPF. AMSU TOTAL PRECIPITABLE WATER VALUES
WERE AROUND 2.0 INCHES OUT AT 40N/144W. LATEST GFS HAS 6-HR RAINFALL
UP TO AN INCH ALONG THE COAST 06Z-12Z WED AND UP TO 2 INCHES 12Z-18Z.
COMBINE THAT WITH 60-75 KT 850 MB SWLY FLOW...THE OROGRAPHIC
COMPONENT SHOULD BE TREMENDOUS. BY 00Z THU THE CASCADE SNOW LEVELS
WILL BE UP ABOVE 3500 FEET...EXCEPT FOR THE S WA CASCADES AND EXTREME
N OREGON CASCADES CLOSEST TO THE GORGE. BY 06Z THU SNOW LEVELS GO UP
TO 4000 FEET NEAR MT. HOOD TO OVER 7000 FEET IN THE LANE COUNTY
CASCADES. THE NAM SHOWS ANOTHER SYSTEM DEVELOPING ALONG THE LEFT-OVER
BAROCLINIC ZONE OVER SWRN OREGON AND NRN CA THU WILL IMPACT THE
FORECAST AREA THU. WEISHAAR
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SEVERAL
SIGNIFICANT STORMS WILL TRACK OVER THE PACIFIC NORTHWEST THROUGH MUCH
FOR THE EXTENDED PERIOD. SNOW LEVELS REMAIN WELL ABOVE 3000 FEET WITH
THE SYSTEM THE MOVES THROUGH LATE FRIDAY...MAINTAINING HEAVY RAIN
ACROSS THE FORECAST AREA INTO SATURDAY. THE NEXT SYSTEM APPROACHES
LATE SATURDAY... BRINGING A THREAT FOR STRONG WINDS ALONG THE COAST
SATURDAY NIGHT INTO SUNDAY. SNOW LEVELS ARE EXPECTED TO DROP WITH
THIS SYSTEM...SO AREAS ABOVE ABOUT 1500 TO 2000 FEET CAN EXPECT SNOW
THROUGH SUNDAY. MODERATE PRECIPITATION CONTINUES INTO EARLY NEXT WEEK
UNDER A WESTERLY FLOW PATTERN...WITH ANOTHER POSSIBLY STRONG SYSTEM
BY MONDAY NIGHT. WILL CONTINUE TO MAINTAIN ABUNDANT PRECIPITATION
AMOUNTS AND COOLER TEMPERATURES THROUGH NEXT WEEKEND.
WILL BE KEEPING A CLOSE EYE ON ANY HYDRO ISSUES THAT WILL LIKELY
APPEAR BY THURSDAY AND FRIDAY AS RISING RIVER LEVELS ARE A CONCERN.
BROWN
&&
.AVIATION...STEADY LIGHT TO MODERATE RAIN WILL CONTINUE THIS EVENING
WITH WIDESPREAD MVFR CONDITIONS AND TRENDING TO IFR AS
PRECIPITATION PICKS UP LATER TONIGHT. LOCATIONS NORTH AND WEST OF
KPDX WILL SEE SNOW MIXED IN...AS WELL AS IN THE COLUMBIA RIVER
GORGE. BUT SOUTHERLY WINDS HAVE NOW EASED AROUND PORTLAND AND
TROUTDALE...AND NOW WE ARE SEEING SNOW AT KTTD AND RAIN/SNOW AT
KPDX. FEEL PRETTY CONFIDENT THAT VALLEY LOCATIONS SOUTH OF AURORA OR
SO WILL REMAIN ALL RAIN TONIGHT. THE POTENTIAL FOR SNOW ARE THE VERY
STRONG WINDS EXPECTED AT THE COAST AND POTENTIALLY INLAND AS
WELL...THOUGH THE INLAND WINDS ARE LESS CERTAIN AT THIS TIME.
PRECIPITATION TRANSITIONS TO ALL MODERATE TO HEAVY RAIN DURING THE
DAY BEFORE EASING TOMORROW NIGHT...AND EXPECT ALL LOCATIONS EXCEPT
THE GORGE TO BE RAIN BY MIDDDAY. EXPECT A MIX OF MVFR AND MORE LIKELY
IFR TO CONTINUE. OF ADDITIONAL CONCERN ARE THE STRONG SOUTHERLY
WINDS TOMORROW THAT WILL BE FOUND NOT ONLY AT THE COAST...BUT EXPECT
BREEZY TO WINDY CONDITIONS IN THE VALLEY...WITH THE STRONGEST VALLEY
WINDS FROM SALEM SOUTH.
KPDX AND APPROACHES...EXPECT A RAIN/SNOW MIX TO CONTINUE THIS
EVENING...AND THEREFORE VARYING CONDITIONS FROM MVFR TO
IFR...BEFORE HEAVY PRECIPITATION ARRIVES OVERNIGHT WITH
PREDOMINANT IFR REGARDLESS OF PRECIP TYPE. IT IS POSSIBLE TO SEE
ACCUMULATING SNOW AT THE TERMINAL MAINLY OVERNIGHT. LIKE MOST
STORMS IT WILL BE SPLITTING HAIRS TO DETERMINE IF IT WILL STICK AT
KPDX OR NOT. LATEST GUIDANCE HAS NOT CHANGED MUCH...BUT WE WILL
CONTINUE TO WATCH AS TROUTDALE IS NOW SEEING ALL SNOW AND FALLING
TEMPERATURES. IF COLD AIR LINGERS LONG ENOUGH THE WORST CASE
SCENARIO WOULD BE 4 PLUS INCHES WHILE MOST GUIDANCE POINTS TO 1 TO
3 INCHES OF VERY WET SLUSHY ACCUMULATION IF ANY BEFORE A CHANGE OVER
TO RAIN. THAT SAID...MOST GUIDANCE IS TOO WARM ON SFC TEMPS AND
DEWPOINTS AT THE MOMENT...AND HAVE INCREASED CONCERNS ON STICKING
SNOW...GIVEN HEAVIER PRECIP RATES OVERNIGHT. SNOW WILL BE FALLING
HARD AT ELEVATIONS ABOVE 500 FT.
CONFIDENCE LOW ON SPECIFIC SOUTHERLY WINDS TOMORROW...BUT EXPECT
BREEZY CROSS RUNWAY WINDS. KMD/WOLFE
&&
.MARINE...AFTER A RELATIVE LULL IN COASTAL WATERS WINDS THIS
EVENING...EXPECT
WINDS AND SEAS TO RAPIDLY INCREASE LATE TONIGHT AND TOMORROW NAM
AND GFS BOUNDARY LAYER WIND SPEED BOTH REACH 60-70 KT FOR A SHORT
TIME IN THE MORNING...AND WITH 925-850 MB WINDS IN THE 80+ KNOT
RANGE. SOLID STORM FORCE WINDS WITH A PERIOD OF HURRICANE FORCE
WINDS STILL ON TRACK.
STARTING WEDNESDAY MORNING MORNING A VERY STRONG SYSTEM ARRIVES AND
BRINGS WIND GUSTS IN EXCESS OF 65 KTS TO A GOOD PORTION OF THE
CENTRAL OREGON COASTAL WATERS...SO HAVE ISSUED A HURRICANE FORCE
WIND WARNING FROM 4 AM UNTIL 1 PM PST FOR THE CENTRAL COASTAL
WATERS. THE CENTER OF LOW PRES LOOKS TO PASS RIGHT OVER ASTORIA.
THEREFORE THE NORTHERN WATERS LOOK TO ESCAPE THE STRONGEST WINDS
BUT WINDS WILL LIKELY BE IN THE STRONG STORM FORCE GUST ARENA
DUE TO THE LOW PLACEMENT...THERE MAY BE AREAS WHERE WINDS QUICKLY
SWITCH FROM STRONG OFFSHORE TO VERY STRONG SOUTHWEST. THIS IS AN
EXTREMELY DANGEROUS STORM. PLEASE TAKE NECESSARY PRECAUTIONS!
WILL MAINTAIN A HIGH SURF ADVISORY FOR THE CENTRAL OREGON COAST
WEDNESDAY AND THE COASTAL FLOOD ADVISORY FOR TIDAL OVERFLOW FOR
BOTH THE NORTH AND CENTRAL OREGON COAST. HIGH TIDE IN THE EARLY
MORNING AND STRONG TIDAL ANOMALY EXPECTED GIVEN THE STORM
STRENGTH. S/SW FACING LOCALES WILL EXPERIENCE THE ROUGHEST SURF
CONDITIONS. CONFIDENCE IS LOWER FOR THE NORTH OREGON COAST WITH
LOWER FORECAST SEAS WITH SHORT LOW PERIODS...BUT AGAIN NOT OUT OF
THE QUESTION EITHER AS WE GET CLOSER TO THE EVENT AND SEE HOW
QUICKLY SEAS BUILD. KMD/WOLFE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING UNTIL 6 PM PST WEDNESDAY FOR NORTHERN
OREGON CASCADE FOOTHILLS-NORTHERN OREGON CASCADES-UPPER
HOOD RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE.
WINTER STORM WARNING UNTIL 3 PM PST WEDNESDAY FOR CASCADE
FOOTHILLS IN LANE COUNTY-CASCADES IN LANE COUNTY.
WINTER WEATHER ADVISORY UNTIL 1 PM PST WEDNESDAY FOR GREATER
PORTLAND METRO AREA.
WIND ADVISORY FROM NOON TO 6 PM PST WEDNESDAY FOR GREATER
PORTLAND METRO AREA.
WINTER WEATHER ADVISORY UNTIL 10 AM PST WEDNESDAY FOR CENTRAL
WILLAMETTE VALLEY-LOWER COLUMBIA-NORTH OREGON COAST-SOUTH
WILLAMETTE VALLEY.
HIGH WIND WARNING FROM 11 PM THIS EVENING TO 4 PM PST WEDNESDAY
FOR CENTRAL COAST RANGE OF WESTERN OREGON-CENTRAL OREGON
COAST.
WINTER STORM WARNING UNTIL 6 AM PST WEDNESDAY FOR CENTRAL COAST
RANGE OF WESTERN OREGON.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM PST WEDNESDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
HIGH SURF ADVISORY FROM 4 AM TO 7 PM PST WEDNESDAY FOR CENTRAL
OREGON COAST.
WINTER STORM WARNING UNTIL NOON PST WEDNESDAY FOR COAST RANGE
OF NORTHWEST OREGON.
WIND ADVISORY FROM 6 AM TO 4 PM PST WEDNESDAY FOR CENTRAL
WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY.
HIGH WIND WARNING FROM 1 AM TO 4 PM PST WEDNESDAY FOR COAST
RANGE OF NORTHWEST OREGON-NORTH OREGON COAST.
WA...WINTER STORM WARNING UNTIL 6 PM PST WEDNESDAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS-SOUTH WASHINGTON CASCADES-
WESTERN COLUMBIA RIVER GORGE.
WINTER WEATHER ADVISORY UNTIL 1 PM PST WEDNESDAY FOR GREATER
VANCOUVER AREA.
WIND ADVISORY FROM NOON TO 6 PM PST WEDNESDAY FOR GREATER
VANCOUVER AREA.
WINTER WEATHER ADVISORY UNTIL 10 AM PST WEDNESDAY FOR I-5
CORRIDOR IN COWLITZ COUNTY-SOUTH WASHINGTON COAST.
WINTER STORM WARNING UNTIL NOON PST WEDNESDAY FOR WILLAPA HILLS.
PZ...STORM WARNING FROM 1 AM TO 4 PM PST WEDNESDAY FOR COASTAL
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10
NM-WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM
10 TO 60 NM.
STORM WARNING FROM 1 AM TO 4 AM PST WEDNESDAY FOR COASTAL
WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-WATERS FROM
CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
HURRICANE FORCE WIND WARNING FROM 4 AM TO 1 PM PST WEDNESDAY
FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH WED
AFTERNOON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1105 AM CST WED JAN 18 2012
.UPDATE...CLEARING TREND IS A BIT SLOWER THAN ANTICIPATED. THUS
HAVE ADJUSTED CLOUD CONDITIONS AND LOWERS MAX TEMPS IN THE ERN
HALF BY 1-2 DEGREES.
JLM
&&
.PREV DISCUSSION... /ISSUED 635 AM CST WED JAN 18 2012/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
LOW CLOUDS < 3K FEET CONTINUING TO STREAM DOWN FROM THE NORTH AND
INTO THE TENNESSEE VALLEY. 12Z OHX RAOB SHOWING ABOUT A 50
MILLIBAR LAYER OF MOISTURE BASED AROUND 900 MILLIBARS WITH COLD
AIR ADVECTION ON TOP OF THIS LAYER AND A STRONG SUBSIDENCE
INVERSION. CLEARED CLOUDS AT BNA AROUND 16Z AND 18Z AT CSV. THIS
IS IN LINE WITH LATEST RUC AND LAMP GUIDANCE. ONCE CLOUDS CLEAR
LOOK FOR VFR THROUGH THE PERIOD.
BOYD
PREV DISCUSSION... /ISSUED 319 AM CST WED JAN 18 2012/
DISCUSSION...
FEW OVERALL CHANGES MADE TO THE FORECAST OVER THE NEXT WEEK
DESPITE A VERY ACTIVE WEATHER PATTERN IN STORE FOR THE MID STATE.
FOR TODAY...NOTABLY COLDER THIS MORNING VERSUS 24 HOURS AGO WITH
TEMPERATURES NOW IN THE UPPER 20S TO LOW 30S ACROSS THE MID STATE.
MICROWAVE SATELLITE IMAGERY SHOWS BROKEN LOW STRATUS CONTINUING TO
SPREAD IN FROM THE NORTH...SO APPEARS MOSTLY CLOUDY SKIES WILL BE
SEEN THIS MORNING BEFORE CLOUDS BREAK SOME BY THIS AFTERNOON.
DESPITE THIS...1024MB COLD SURFACE HIGH WILL SETTLE OVER THE CWA
TODAY AND HIGHS WILL STRUGGLE TO REACH 40 DEGREES.
SURFACE HIGH SHIFTS EAST TONIGHT WITH SOUTHERLY FLOW RETURNING TO
MID TN INTO THURSDAY...WITH TEMPS WARMING UP INTO THE UPPER 40S
AND 50S BY THURSDAY AFTERNOON. CLIPPER TYPE SYSTEM MOVING ACROSS
THE GREAT LAKES WILL CAUSE ANOTHER COLD FRONT TO SAG INTO THE AREA
THURSDAY NIGHT...BUT ANY PRECIP WITH FRONT EXPECTED TO STAY WELL
TO OUR NORTH AND EAST. NEXT UPPER WAVE MOVING INTO THE PLAINS ON
FRIDAY WILL INDUCE CYCLOGENESIS OVER THE ARKLATEX FRIDAY
NIGHT...WITH SURFACE LOW THEN MOVING ACROSS THE MID STATE THROUGH
SATURDAY. INCREASING WAA REGIME AHEAD OF LOW WILL ALLOW FOR A FEW
SHOWERS TO DEVELOP DURING THE DAY ON FRIDAY...BUT MUCH MORE
NUMEROUS SHOWERS AND EVEN A FEW THUNDERSTORMS ARE EXPECTED FRIDAY
NIGHT INTO SATURDAY WITH LIKELY POPS AS A COLD FRONT SWEEPS ACROSS
BEHIND THE SURFACE LOW.
CWA BRIEFLY DRIES OUT SATURDAY NIGHT BEFORE SOUTHERLY FLOW RETURNS
YET AGAIN WITH SHOWERS DEVELOPING ON SUNDAY AND EXPANDING IN
INTENSITY AND COVERAGE SUNDAY NIGHT INTO MONDAY. VERY LOW
CONFIDENCE ON FORECAST FROM THIS POINT ONWARD AS ECMWF HAS SHOWN
CONSIDERABLE INCONSISTENCY FROM RUN TO RUN...BUT 00Z RUN APPEARS
TO BE COMING CLOSER TO LATEST GFS. FOR NOW...HAVE GONE WITH A
BLEND OF THE TWO FOR TEMPS...WHICH ARE CONSIDERABLY ABOVE MEX MOS
IN SOME CASES...AND KEPT LOW POPS THROUGH THE END OF THE FORECAST
PERIOD UNTIL BETTER MODEL CONSENSUS EMERGES. LONG RANGE MODELS
CONTINUE TO DEPICT A VERY ACTIVE WEATHER PATTERN CONTINUING
THROUGH THE REST OF JANUARY WITH SYSTEMS AFFECTING THE TN VALLEY
EVERY 3 DAYS OR SO...WHICH KEEPS THE MID STATE IN A GENERAL WARM
AND RAINY REGIME.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
18
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
635 AM CST WED JAN 18 2012
.UPDATE...FOR 12Z AVIATION FORECAST
&&
.AVIATION...
LOW CLOUDS < 3K FEET CONTINUING TO STREAM DOWN FROM THE NORTH AND
INTO THE TENNESSEE VALLEY. 12Z OHX RAOB SHOWING ABOUT A 50
MILLIBAR LAYER OF MOISTURE BASED AROUND 900 MILLIBARS WITH COLD
AIR ADVECTION ON TOP OF THIS LAYER AND A STRONG SUBSIDENCE
INVERSION. CLEARED CLOUDS AT BNA AROUND 16Z AND 18Z AT CSV. THIS
IS IN LINE WITH LATEST RUC AND LAMP GUIDANCE. ONCE CLOUDS CLEAR
LOOK FOR VFR THROUGH THE PERIOD.
BOYD
&&
.PREV DISCUSSION... /ISSUED 319 AM CST WED JAN 18 2012/
DISCUSSION...
FEW OVERALL CHANGES MADE TO THE FORECAST OVER THE NEXT WEEK
DESPITE A VERY ACTIVE WEATHER PATTERN IN STORE FOR THE MID STATE.
FOR TODAY...NOTABLY COLDER THIS MORNING VERSUS 24 HOURS AGO WITH
TEMPERATURES NOW IN THE UPPER 20S TO LOW 30S ACROSS THE MID STATE.
MICROWAVE SATELLITE IMAGERY SHOWS BROKEN LOW STRATUS CONTINUING TO
SPREAD IN FROM THE NORTH...SO APPEARS MOSTLY CLOUDY SKIES WILL BE
SEEN THIS MORNING BEFORE CLOUDS BREAK SOME BY THIS AFTERNOON.
DESPITE THIS...1024MB COLD SURFACE HIGH WILL SETTLE OVER THE CWA
TODAY AND HIGHS WILL STRUGGLE TO REACH 40 DEGREES.
SURFACE HIGH SHIFTS EAST TONIGHT WITH SOUTHERLY FLOW RETURNING TO
MID TN INTO THURSDAY...WITH TEMPS WARMING UP INTO THE UPPER 40S
AND 50S BY THURSDAY AFTERNOON. CLIPPER TYPE SYSTEM MOVING ACROSS
THE GREAT LAKES WILL CAUSE ANOTHER COLD FRONT TO SAG INTO THE AREA
THURSDAY NIGHT...BUT ANY PRECIP WITH FRONT EXPECTED TO STAY WELL
TO OUR NORTH AND EAST. NEXT UPPER WAVE MOVING INTO THE PLAINS ON
FRIDAY WILL INDUCE CYCLOGENESIS OVER THE ARKLATEX FRIDAY
NIGHT...WITH SURFACE LOW THEN MOVING ACROSS THE MID STATE THROUGH
SATURDAY. INCREASING WAA REGIME AHEAD OF LOW WILL ALLOW FOR A FEW
SHOWERS TO DEVELOP DURING THE DAY ON FRIDAY...BUT MUCH MORE
NUMEROUS SHOWERS AND EVEN A FEW THUNDERSTORMS ARE EXPECTED FRIDAY
NIGHT INTO SATURDAY WITH LIKELY POPS AS A COLD FRONT SWEEPS ACROSS
BEHIND THE SURFACE LOW.
CWA BRIEFLY DRIES OUT SATURDAY NIGHT BEFORE SOUTHERLY FLOW RETURNS
YET AGAIN WITH SHOWERS DEVELOPING ON SUNDAY AND EXPANDING IN
INTENSITY AND COVERAGE SUNDAY NIGHT INTO MONDAY. VERY LOW
CONFIDENCE ON FORECAST FROM THIS POINT ONWARD AS ECMWF HAS SHOWN
CONSIDERABLE INCONSISTENCY FROM RUN TO RUN...BUT 00Z RUN APPEARS
TO BE COMING CLOSER TO LATEST GFS. FOR NOW...HAVE GONE WITH A
BLEND OF THE TWO FOR TEMPS...WHICH ARE CONSIDERABLY ABOVE MEX MOS
IN SOME CASES...AND KEPT LOW POPS THROUGH THE END OF THE FORECAST
PERIOD UNTIL BETTER MODEL CONSENSUS EMERGES. LONG RANGE MODELS
CONTINUE TO DEPICT A VERY ACTIVE WEATHER PATTERN CONTINUING
THROUGH THE REST OF JANUARY WITH SYSTEMS AFFECTING THE TN VALLEY
EVERY 3 DAYS OR SO...WHICH KEEPS THE MID STATE IN A GENERAL WARM
AND RAINY REGIME.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1117 PM CST TUE JAN 17 2012
.DISCUSSION...SEE AVIATION SECTION BELOW.
&&
.AVIATION...MVFR LEVEL CLOUDS HAVE REFORMED ACROSS THE COASTAL
COUNTIES IN THE WAKE OF A COLD FRONT THAT MOVED THROUGH THE AREA
EARLIER THIS EVENING. SATELLITE IMAGES SHOW THAT THIS CLOUD DECK
IS ERODING FROM N TO S AND A HIGH LEVEL CIRRUS DECK IS MOVING IN
FROM THE SW WHICH IS INHIBITING LOW CLOUDS FROM FORMING ACROSS THE
W CWA. NAM FCSTD SOUNDINGS AND TIME HEIGHT ANALYSIS SHOW MVFR
CLOUD DECK WHICH LOWERS THROUGH WED AFTERNOON. ON THE OTHERHAND
THE GFS FCSTD SOUNDINGS/TIME HEIGHT SHOW CIGS RISING THROUGH WED
MORNING AND ARE PROGD TO BE MORE SCT. WENT WITH PREVAILING VFR
CONDITIONS WITH TEMPO BKN MVFR FOR ONLY ALI AND CRP THROUGH AROUND
10Z. THEN VFR AREA WIDE THROUGH WED AFTERNOON. MVFR CIGS ARE
EXPECTED BY WED EVENING AS LIGHT NLY WINDS SHIFT AROUND TO THE SE
AND S.
&&
.PREV DISCUSSION... /ISSUED 746 PM CST TUE JAN 17 2012/
DISCUSSION...FRONTAL BDRY IS CURRENTLY APPROACHING CORPUS AND IS
ORIENTED FROM SW TO NE ALONG THE COAST. THE FRONT SHOULD BE
THROUGH KINGSVILLE 815-830PM TIMEFRAME AND ACROSS THE COASTAL
WATERS BTWN 8-10PM. DEWPOINTS HAVE DROPPED AROUND 20 DEGREES
ACROSS THE NRN TIER OF THE CWA SINCE THIS AFTERNOON. THIS DRIER
AIRMASS WILL CONTINUE TO MOVE S THROUGH TONIGHT WITH MUCH COOLER
MN TEMPS EXPECTED OVERNIGHT. STRONG OFFSHORE WINDS ARE STILL
EXPECTED TO DVLP OVER THE MARINE ZONES IN THE WAKE OF THE FRONT.
CURRENT FCST LOOKS ON TRACK WITH CURRENT TRENDS AND EXPECTED
CONDITIONS...THEREFORE NO MAJOR CHANGES AT THIS TIME.
PREV DISCUSSION... /ISSUED 540 PM CST TUE JAN 17 2012/
DISCUSSION...SEE 00Z AVIATION DISCUSSION.
AVIATION...VFR THROUGH THE PERIOD WITH ONLY MID/HI CLOUDS/CIGS
MAINLY TONIGHT. WINDS SHOULD PICK UP WHERE THEY HAVE NOT...WITH
WINDS BECOMING NNE AT KCRP BY 02Z (SEA BREEZE HAS GONE THROUGH
AIRPORT). GUSTY NNE WINDS THIS EVENING AND MUCH OF OVERNIGHT AS
AREA GET STRONG PRESSURE RISES (WITH STRONG PRESSURE
GRADIENT)...THEN DECREASES BY DAYBREAK WITH WINDS EVENTUALLY
BECOMING NE/E LATE AS HIGH BEGINS TO MOVE EAST.
PREV DISCUSSION... /ISSUED 337 PM CST TUE JAN 17 2012/
SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...A COLD FRONT IS
CURRENTLY DRAPED FROM NORTH OF VICTORIA TO NEAR LAREDO. THE FRONT
WILL PUSH THROUGH THE REST OF THE AREA LATE THIS
AFTERNOON...PUSHING OFFSHORE BY EVENING. WITH A CAP REMAINING OVER
THE AREA DONT EXPECT TO SEE SHOWERS OVER LAND...BUT MAY BE ABLE TO
DEVELOP A FEW OFFSHORE THIS EVENING. RUC GUIDANCE HAS SEEMED
PRETTY REASONABLE WITH FRONTAL TIMING AND WINDS SO LARGELY GOING
WITH THAT FOR WINDS THIS EVENING...EXPECTING A BRIEF INCREASE OVER
LAND AREAS AND THEN AN INCREASE TO 20 TO 25 KNOTS OVER THE WATER.
A SMALL CRAFT ADVISORY IS IN EFFECT FROM 8PM THIS EVENING THROUGH
9AM TOMORROW. BEHIND THE FRONT HIGH PRESSURE WILL QUICKLY BUILD IN
AND LEAD TO LIGHT WINDS TOMORROW ACROSS THE AREA. BY WEDNESDAY
NIGHT WINDS ARE ALREADY SHIFTING TO THE SOUTHEAST. AN AREA OF MID
AND HIGH LEVEL CLOUDS PUSHING IN FROM THE WEST SHOULD KEEP TEMPS
MAINLY IN THE 40S THIS EVENING...WITH SOME UPPER 30S IN THE FAR
NORTHEAST. AFTER NEAR RECORD HIGHS TODAY...MAX TEMPS WILL BE IN
THE 60S AREA WIDE TOMORROW. SOUTHERLY WINDS KEEP TEMPS UP
WEDNESDAY NIGHT.
LONG TERM (THURSDAY THROUGH TUESDAY)...THURSDAY THROUGH SATURDAY
WILL FEATURE A MAINLY ZONAL FLOW ALOFT WITH A WARMING TREND ACROSS
SOUTH TEXAS...AND ABOVE NORMAL HIGHS. A GRADUAL MOISTENING OF THE
LOWER LEVELS WILL ALSO TAKE PLACE...WITH PERIODS OF OVERNIGHT AND
MORNING FOG/SEA FOG TO CONTEND WITH FRI/SAT. A WEAK FRONTAL BOUNDARY
WILL STALL OVER THE NORTHERN CWA SATURDAY MORNING AND WASH OUT. NEXT
CHANCE OF PRECIP WILL COME LATE SUNDAY INTO MONDAY MORNING AS A
SOUTHERN STREAM SHORTWAVE APPROACHES FROM BAJA CALIFORNIA. WILL KEEP
POPS IN THE 20% RANGE FOR NOW AS THERE HAVE BEEN SOME MODEL
CONSISTENCY ISSUES WITH TIMING/STRENGTH OF DISTURBANCE. THE
DISTURBANCE BECOMES ABSORBED INTO LARGER TROUGH TO THE NORTHWEST ON
MONDAY...WHICH EVENTUALLY PUSHES A COLD FRONT INTO THE AREA TUESDAY.
AGAIN...TIMING AND STRENGTH DIFFERENCES WITH RESPECT TO UPPER LEVEL
TROUGH AND CORRESPONDING COLD FRONT BETWEEN ECMWF/GFS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 63 48 79 58 / 10 0 0 0 0
VICTORIA 38 61 46 75 57 / 10 0 0 0 0
LAREDO 47 64 52 78 58 / 0 0 0 0 0
ALICE 45 64 48 80 58 / 10 0 0 0 0
ROCKPORT 43 60 49 69 58 / 10 0 0 0 0
COTULLA 41 63 43 78 54 / 0 0 0 0 0
KINGSVILLE 46 64 48 80 58 / 10 0 0 0 0
NAVY CORPUS 47 61 51 73 60 / 10 0 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR...
COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...
COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL
OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20
TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP
CHANNEL FROM 20 TO 60 NM.
&&
$$
TE/81...SHORT TERM/AVIATION
GW/86...LONG TERM
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
903 PM CST THU JAN 19 2012
.SHORT TERM...TONIGHT THROUGH TOMORROW
903 PM CST THU JAN 19 2012
MAIN CONCERN CONTINUES TO BE WITH THE SNOW FOR TOMORROW WITH NO
CHANGES PLANNED FOR THE HEADLINES THIS EVENING.
A MID LEVEL SHORTWAVE TROUGH IS MAKING ITS WAY ACROSS ROCKIES WITH
SOME MID TO UPPER LEVEL CLOUD COVER STARTING TO ADVECT INTO THE
REGION ALONG A STRONG UPPER LEVEL JET STREAK OF ABOUT 160KTS AT
250MB BASED ON 20.00Z RAOBS.
AS THIS TROUGH EJECTS OUT OF THE ROCKIES INTO THE PLAINS...SNOW
WILL BEGIN TO FORM OVERNIGHT AND START SPREADING INTO THE
REGION AROUND 3AM OR SO. THE 20.00Z NAM AND 19.21Z SREF HAVE
TRICKLED IN AND ARE STILL PAINTING A SIMILAR PICTURE TO THEIR
PREVIOUS RUNS. THE 19.21Z SREF IS SHOWING SOME HIGHER
PROBABILITIES OF 4 INCHES OR MORE IN A 12 HOUR PERIOD ALONG THE
AXIS OF WHERE THE CURRENT ADVISORY IS LAID OUT WITH 0 PERCENT
PROBABILITIES OF 8 INCHES OR MORE. THE NAM CONTINUES TO BE THE
WORRISOME MODEL WITH HIGHER SNOWFALL TOTALS ALONG A NARROW BAND
ACROSS NORTHEAST IOWA WHERE THE QPF AMOUNTS CAME UP A BIT WITH THE
20.00Z RUN. THE OTHER ISSUE IS WITH THE 750MB WARM LAYER AND HOW
WARM IT WILL BE TOMORROW WHICH WILL DIRECTLY AFFECT HOW DEEP THE
DENDRITIC GROWTH ZONE IS. THE NAM HAS TRENDED TO BE WARMER IN THIS
LAYER WHILE THE GFS HAS BEEN COOLER WITH MUCH OF THE THERMAL
PROFILE FROM THE SURFACE UP TO 550MB IN THE DGZ. THE 19.22Z TO
20.01Z RUC FORECAST SOUNDINGS HAVE NOT HELPED MUCH TO THIS POINT
IN DETERMINING WHICH WAY TO TREND AS EARLIER THEY HAD GONE WITH A
COOLER WARM LAYER...BUT THE LATEST COUPLE OF RUNS HAVE GONE TOWARD
THE NAM THINKING SO PERHAPS THAT IS THE WAY TO TREND.
LONG STORY SHORT...HAVE COLLABORATED WITH NEIGHBORING OFFICES AND
HAVE DECIDED TO HOLD OFF ON ANY UPGRADES OR EXPANSIONS OF THE
CURRENT HEADLINED AREA. THE MAIN CONCERNS WERE WHETHER TO UPGRADE
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN TO A WINTER STORM
WARNING FOR SOME POSSIBLE BANDING AND HIGHER SNOWFALL
TOTALS IN THE 6 TO 8 INCH RANGE...ALONG WITH PUSHING THE ADVISORY
NORTH A TIER OF COUNTIES FROM WABASHA COUNTY TO JACKSON COUNTY.
WITH MUCH OF THE OTHER 20.00Z GUIDANCE NOT IN YET...HAVE DECIDED
THAT IT WOULD BE MORE PRUDENT TO LET THE MIDNIGHT CREW GET SOME
MORE INFORMATION TO TAKE A BETTER SHOT AT HOW THE SYSTEM LOOKS AS
IT GETS OUT OF THE ROCKIES.
PLEASE SEE THE PREVIOUS AFD FOR COMMENTS ON THE WEATHER BEYOND
TOMORROW.
20.00Z NAM AND 19.21Z SREF GUIDANCE HAS STARTED TRICKLING
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
320 PM CST THU JAN 19 2012
UPPER TROUGH OVER THE PLAINS LOOKS TO LIFT NORTHEAST THROUGH THE
AREA SUNDAY NIGHT AND AWAY FROM THE AREA ON MONDAY. CERTAINLY THIS
BEARS WATCHING FOR TIMING GIVEN THE TREND FOR THIS TROUGH TO BE
AMPLIFIED AND SLOWER. IN FACT THE NEW 19.12Z ECMWF SLOWED DOWN THE
TROUGH A BIT MORE. SHOULD SEE ANY RAIN/FREEZING RAIN CHANGE OVER TO
SNOW THROUGH THE NIGHT SUNDAY NIGHT...WITH ALL SNOW MONDAY...THOUGH
AGAIN THE PRECIPITATION SHOULD BE WINDING DOWN MONDAY. MAY HAVE TO
WATCH FOR POTENTIAL ADVISORY SNOW SUNDAY NIGHT...AND POSSIBLY INTO
MONDAY IF THE NEW ECMWF IS CORRECT.
REST OF NEXT WEEK CONTINUES TO SHOW A SOMEWHAT ACTIVE PATTERN...WITH
MODELS IN VERY GOOD AGREEMENT SHOWING SHORTWAVE TROUGHS MOVING
THROUGH TUESDAY NIGHT INTO WEDNESDAY...AS WELL AS ON THURSDAY.
HOWEVER...NONE OF THESE TROUGHS LOOK TO HAVE A LOT OF MOISTURE WITH
THEM...LIKELY SHUNTED OFF BY THE DEEPER SUNDAY NIGHT/MONDAY TROUGH.
FOLLOWED A CONSENSUS APPROACH GIVEN THE GOOD AGREEMENT...RESULTING
IN MOSTLY 20-40 PERCENT CHANCES FOR THESE TROUGHS. TEMPERATURES WILL
BE WARMER NEXT WEEK THAN THIS WEEK...THANKS TO THE MAIN POLAR
WESTERLIES SHIFTING WELL NORTH INTO CANADA. IT DOES NOT APPEAR THAT
ENOUGH WARM AIR ENTERS ANY OF THE TROUGHS TO RESULT IN LIQUID
PRECIPITATION...THOUGH.
&&
.AVIATION...TONIGHT AND FRIDAY
539 PM CST THU JAN 19 2012
THE FOCUS AT THE TAF SITES CONTINUES TO BE ON THE SNOW HEADED THIS
WAY TOMORROW MORNING AND AFTERNOON.
CONDITIONS WILL BE IDEAL THIS EVENING INTO THE EARLY OVERNIGHT
HOURS AS WINDS WILL BE LIGHT AND SKIES CLEAR AS THE CORE OF A
RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION.
THE INITIAL QUESTION IS WHEN THE SNOW WILL BEGIN TO FALL AT RST
AND LSE. THE PREVIOUS TIMING FROM THE 18Z TAFS STILL LOOKS ON
TRACK RIGHT NOW WITH THE SNOW STARTING AT RST AROUND 10Z AND LSE
AROUND 12Z. THE STRONGEST FORCING WILL COME IN SHORTLY AFTER THE
SNOW STARTS AND SHOULD LAST FOR A GOOD 5 TO 7 HOURS THAT WILL
LIKELY RESULT IN VISIBILITY DROPPING TO 1/4 TO 1/2SM OVER THAT
TIME FRAME. THIS STRONGER FORCING WILL MOVE EAST OF THE TAF REGION
EARLY IN THE AFTERNOON...BUT THERE STILL COULD BE ENOUGH LEFT OVER
TO PROVIDE A FEW MORE HOURS OF LIGHT SNOW. SOME OF THE SHORT TERM
GUIDANCE IS SUGGESTING THAT THE SNOW SHOULD END AT RST BY MID
AFTERNOON...POSSIBLY AS WELL AT LSE. HOWEVER...AN IFR CLOUD DECK
SHOULD HOLD ON THROUGH 00Z...SO HAVE HELD ONTO THE LOW CONDITIONS
GOING THROUGH THE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 PM CST THU JAN 19 2012
WI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR
WIZ041>044-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
MNZ086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
539 PM CST THU JAN 19 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
320 PM CST THU JAN 19 2012
MAIN FORECAST CONCERNS ARE ON THE ACCUMULATING SNOW EVENT FOR LATE
TONIGHT INTO FRIDAY...AS WELL AS A MIXED PRECIPITATION EVENT FOR
SUNDAY.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A WEST-NORTHWEST FLOW FROM THE PACIFIC NORTHWEST INTO THE
OHIO VALLEY WITH A TROUGH OVER THE WESTERN GREAT LAKES REGION.
ALSO NOTED ON WATER VAPOR IS A SHORTWAVE TROUGH JUST OFF THE COAST
OF OREGON. FAST JET STREAM IN THE WEST-NORTHWEST FLOW...WITH THE
RUC TROPOPAUSE WIND SPEEDS SHOWING 130-160KT FROM FAR SOUTHERN
SASKATCHEWAN INTO FAR WESTERN KENTUCKY. WITH THE FORECAST AREA ON
THE NORTHEAST/SUBSIDENT SIDE OF THE UPPER JET AND ON THE BACK SIDE
OF THE WESTERN GREAT LAKES TROUGH...HIGH PRESSURE IS FAVORED AT
THE SURFACE. THIS HIGH IS CENTERED OVER SOUTHERN MINNESOTA AND
IOWA. ARCTIC AIR REMAINS IN PLACE...NOTED BY SURFACE TEMPERATURES
ONLY JUST ABOVE ZERO...DESPITE PLENTY OF SUN. 12Z SOUNDING PLOT OF
850MB TEMPERATURES REFLECTIVE OF BOTH THE ARCTIC AIR AND THE FAST
UPPER JET...WITH READINGS OF -21 TO -25C AT ABR...MPX AND GRB
WHILE ONLY -9C AT OAX AND -12C AT DVN. A SIMILAR DRAMATIC
DIFFERENCE CAN BE SEEN IN PRECIPITABLE WATER PLOTS. ABR...MPX AND
GRB HAD READINGS OF 0.05 TO 0.1 INCHES OR 20-30 PERCENT OF
NORMAL...WHILE DVN AND OAX REPORTED 0.26 INCHES OR ALMOST 100
PERCENT OF NORMAL. LAST ITEM OF NOTE IS A FRONTOGENETIC BAND OF
SNOW OVER CENTRAL MONTANA. THIS AREA OF FRONTOGENESIS IS ALONG THE
WESTERN EXTENT OF THE AFOREMENTIONED SHARP CONTRAST IN
MOISTURE/850MB TEMPS.
TONIGHT AND FRIDAY...UPPER LEVEL FLOW IS PROGGED TO TURN MORE
WESTERLY/ZONAL DURING THE NEXT 24 HOURS...MOSTLY IN RESPONSE TO THE
TROUGH OFF THE OREGON COAST RAPIDLY MOVING INLAND. THIS TROUGH IS
VERY IMPORTANT TO THE FORECAST AND SPECIFICALLY HOW AMPLIFIED IT IS
AS IT MOVES THROUGH THE CENTRAL PLAINS ON FRIDAY. THE REASON IS THAT
AS THE DPVA AND WARM ADVECTION APPROACHES AHEAD OF THE TROUGH...THE
SHARP CONTRAST IN TEMPERATURES AND MOISTURE NOTED IN THE CURRENT
DISCUSSION WILL LIGHT UP WITH SNOW. ANOTHER FEATURE HELPING TO
PRODUCE THE SNOW WILL END UP BEING A RIGHT ENTRANCE REGION OF THE
CURRENT STRONG UPPER JET...WHICH LIFTS NORTHEAST TONIGHT AND FRIDAY
WITH THE CHANGE IN UPPER FLOW. THEREFORE...WHERE THIS SNOW BAND SETS
UP AND HOW STRONG DEPENDS ON THE AMPLITUDE OF THE TROUGH. RUN TO RUN
THE NAM HAS BEEN THE MOST POTENT WITH THIS TROUGH...THOUGH IT HAS
SPED UP SOME TO COME IN CLOSER WITH THE CONSENSUS WITH THE 19.12Z
RUN. THE CANADIAN HAS BEEN CONSISTENTLY SHOWING A LESS POTENT
TROUGH...KEEPING THE HEAVIER BAND MOSTLY SOUTH OF THE FORECAST
AREA...THOUGH THE LATEST 19.12Z RUN SHOWED A SLIGHT NORTHWARD DRIFT.
THE GFS REMAINS A CONSISTENT COMPROMISE APPROACH BETWEEN THE
CANADIAN AND NAM. ANOTHER ISSUE TO DEAL WITH REMAINS SNOW RATIOS. A
FLATTER SOLUTION ALLOWS FOR A SLOWER EXIT OF THE CURRENT ARCTIC
AIR...SETTING THE STAGE FOR A DEEPER DENDRTIC SNOW GROWTH LAYER.
THIS IS ESPECIALLY TRUE FOR ABOUT THE NORTHERN TWO THIRDS OF THE
FORECAST AREA...WHERE 20 TO 1 SNOW RATIOS ARE LIKELY...NO MATTER
WHAT SOLUTION IS FOLLOWED. ON THE OTHER HAND...THE MORE AMPLIFIED
SOLUTION LIKE THE NAM ADVECTS WARMER MID LEVEL AIR INTO THE
SOUTHERN THIRD OF THE FORECAST AREA...DECREASING THE DENDRITIC
GROWTH ZONE. AROUND 15 TO 1 RATIOS WOULD BE MORE REASONABLE IN
THIS ZONE. IN TERMS OF TIMING...GOOD CONSENSUS FOR THE SNOW TO
MOVE INTO AREAS WEST OF THE MISSISSIPPI RIVER BETWEEN
09-12Z...OVERSPREAD MUCH OF THE AREA FOR 12-18Z WHICH ALSO LOOKS
TO BE THE HEAVIEST SNOW TIME...THEN BEGIN TO EXIT WEST TO EAST
BETWEEN 18-00Z. TRICKY DETERMINING THE HAZARD SCENARIO WITH
QUESTIONS ON THE SNOW TO WATER RATIO AS WELL AS PLACEMENT OF THE
HEAVIER BAND. HIGH CERTAINTY THAT LOCATIONS ALONG AND SOUTH OF
I-90 WILL SEE ADVISORY CRITERIA. NOT ENOUGH CERTAINTY EXISTS TO
PLACE ANY WARNINGS...THOUGH...WITH THE UNCERTAINTY ON MAX QPF
PLACEMENT...FORCING AND SNOW TO WATER RATIOS. 19.15Z SREF PLUMES
ALSO SHOWS A LARGE AMOUNT OF UNCERTAINTY REGARDING AMOUNTS. FUTURE
SHIFTS MAY UPGRADE TO WARNINGS IF THE ZONE OF HEAVIEST QPF CAN BE
NARROWED DOWN. QUICKLY REGARDING TEMPERATURES...SHOULD SEE LOWS
THIS EVENING THEN READINGS RISE AFTER MIDNIGHT TONIGHT INTO FRIDAY
WITH THE CLOUDS/WARM ADVECTION MOVING IN.
FRIDAY NIGHT AND SATURDAY...SHORTWAVE TROUGH THAT MOVED INTO THE
CENTRAL PLAINS FRIDAY CONTINUES HEADING RAPIDLY OFF TO THE EAST
FRIDAY NIGHT...ALLOWING HIGH PRESSURE TO BUILD OVER THE ENTIRE
AREA BY SATURDAY MORNING. SKIES LOOK TO CLEAR AS THE HIGH MOVES
IN...THEREFORE...WITH THE FRESH SNOW WENT TOWARDS THE LOW END OF
GUIDANCE FOR LOWS. FOR SATURDAY...MODELS ARE IN GOOD AGREEMENT
BRINGING A DEEP TROUGH INTO THE WESTERN U.S. AS THIS OCCURS...
HEIGHTS BUILD DOWNSTREAM OVER THE FORECAST AREA...RESULTING IN
FAIRLY STRONG WARM ADVECTION BY THE END OF THE DAY. 850MB TEMPS
CLIMB FROM -8 TO -12C AT 12Z SATURDAY TO -2 TO -6C BY 00Z SUNDAY.
NOT ANTICIPATING ANY PRECIPITATION ON SATURDAY...DUE TO THE DRY
HIGH PRESSURE AREA STILL IN PLACE...THOUGH AN INCREASE OF MID AND
HIGH CLOUD COVER IS LIKELY AS THE DAY GOES ON. GENERALLY FOLLOWED
A BLEND OF GUIDANCE FOR HIGHS.
SATURDAY NIGHT AND SUNDAY...FOCUS OF ATTENTION IS ON THAT NEXT DEEP
TROUGH IN THE WESTERN U.S. AT 00Z SUNDAY. DPROG/DT OF ALL MODELS
SHOWS THIS TROUGH TRENDING RAPIDLY DEEPER AND SLOWING SOMEWHAT.
RIGHT NOW MOST MODELS ARE IN AGREEMENT OF THE TROUGH MOVING INTO THE
PLAINS ON SUNDAY. ALSO OF NOTE IS THAT A POTENT SHORTWAVE IS
INDICATED AT THE BOTTOM OF THE TROUGH...WHICH MAY TURN NEGATIVE TILT
AS IT LIFTS UP THE EAST SIDE OF THE TROUGH TOWARDS THE FORECAST AREA
LATE SUNDAY AND INTO SUNDAY NIGHT. THIS MEANS THE WEATHER IS GOING
TO BE ACTIVE AGAIN...BUT THIS TIME THE TROUGH HAS A SURGE OF WARM
AND MORE MOIST AIR FROM THE GULF OF MEXICO...RESULTING IN ISSUES
WITH PRECIPITATION TYPE. FIRST FOR SATURDAY NIGHT...WARM ADVECTION
DOWNSTREAM SHOULD ALLOW TEMPERATURES TO CLIMB THROUGH THE NIGHT.
ANY PRECIPITATION ASSOCIATED WITH THE WARM ADVECTION LOOKS TO STAY
OFF TO OUR NORTHWEST...MAINLY OVER WESTERN AND NORTHERN MINNESOTA.
BETTER SHOT FOR PRECIPITATION EXISTS ON SUNDAY...ESPECIALLY IN THE
AFTERNOON...AS HEIGHT FALLS FROM THE UPPER TROUGH AND ISENTROPIC
LIFT AHEAD OF THE TROUGH MOVES INTO THE AREA. WITH THE PERSISTENT
WARM ADVECTION...2 METER TEMPERATURES ARE LIKELY TO CLIMB ABOVE
FREEZING FOR MOST OF THE AREA...RESULTING IN POTENTIAL FOR A
MIX/CHANGE TO RAIN AND SNOW. WITH GROUND AND SNOW TEMPERATURES
PROBABLY STAYING BELOW FREEZING...THIS RAIN COULD TURN TO ICE ON
UNTREATED ROADS...THUS THE INTRODUCTION OF FREEZING RAIN TOO INTO
THE FORECAST. NOTE...THERE IS A MID LEVEL DRY AIR LAYER NOTED IN
SOUNDINGS...THOUGH IT DOES NOT LOOK TO BE DEEP ENOUGH OR DRY ENOUGH
AT THIS TIME TO PREVENT ICE FROM ALOFT REACHING DOWN TO THE SURFACE.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
320 PM CST THU JAN 19 2012
UPPER TROUGH OVER THE PLAINS LOOKS TO LIFT NORTHEAST THROUGH THE
AREA SUNDAY NIGHT AND AWAY FROM THE AREA ON MONDAY. CERTAINLY THIS
BEARS WATCHING FOR TIMING GIVEN THE TREND FOR THIS TROUGH TO BE
AMPLIFIED AND SLOWER. IN FACT THE NEW 19.12Z ECMWF SLOWED DOWN THE
TROUGH A BIT MORE. SHOULD SEE ANY RAIN/FREEZING RAIN CHANGE OVER TO
SNOW THROUGH THE NIGHT SUNDAY NIGHT...WITH ALL SNOW MONDAY...THOUGH
AGAIN THE PRECIPITATION SHOULD BE WINDING DOWN MONDAY. MAY HAVE TO
WATCH FOR POTENTIAL ADVISORY SNOW SUNDAY NIGHT...AND POSSIBLY INTO
MONDAY IF THE NEW ECMWF IS CORRECT.
REST OF NEXT WEEK CONTINUES TO SHOW A SOMEWHAT ACTIVE PATTERN...WITH
MODELS IN VERY GOOD AGREEMENT SHOWING SHORTWAVE TROUGHS MOVING
THROUGH TUESDAY NIGHT INTO WEDNESDAY...AS WELL AS ON THURSDAY.
HOWEVER...NONE OF THESE TROUGHS LOOK TO HAVE A LOT OF MOISTURE WITH
THEM...LIKELY SHUNTED OFF BY THE DEEPER SUNDAY NIGHT/MONDAY TROUGH.
FOLLOWED A CONSENSUS APPROACH GIVEN THE GOOD AGREEMENT...RESULTING
IN MOSTLY 20-40 PERCENT CHANCES FOR THESE TROUGHS. TEMPERATURES WILL
BE WARMER NEXT WEEK THAN THIS WEEK...THANKS TO THE MAIN POLAR
WESTERLIES SHIFTING WELL NORTH INTO CANADA. IT DOES NOT APPEAR THAT
ENOUGH WARM AIR ENTERS ANY OF THE TROUGHS TO RESULT IN LIQUID
PRECIPITATION...THOUGH.
&&
.AVIATION...TONIGHT AND FRIDAY
539 PM CST THU JAN 19 2012
THE FOCUS AT THE TAF SITES CONTINUES TO BE ON THE SNOW HEADED THIS
WAY TOMORROW MORNING AND AFTERNOON.
CONDITIONS WILL BE IDEAL THIS EVENING INTO THE EARLY OVERNIGHT
HOURS AS WINDS WILL BE LIGHT AND SKIES CLEAR AS THE CORE OF A
RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION.
THE INITIAL QUESTION IS WHEN THE SNOW WILL BEGIN TO FALL AT RST
AND LSE. THE PREVIOUS TIMING FROM THE 18Z TAFS STILL LOOKS ON
TRACK RIGHT NOW WITH THE SNOW STARTING AT RST AROUND 10Z AND LSE
AROUND 12Z. THE STRONGEST FORCING WILL COME IN SHORTLY AFTER THE
SNOW STARTS AND SHOULD LAST FOR A GOOD 5 TO 7 HOURS THAT WILL
LIKELY RESULT IN VISIBILITY DROPPING TO 1/4 TO 1/2SM OVER THAT
TIME FRAME. THIS STRONGER FORCING WILL MOVE EAST OF THE TAF REGION
EARLY IN THE AFTERNOON...BUT THERE STILL COULD BE ENOUGH LEFT OVER
TO PROVIDE A FEW MORE HOURS OF LIGHT SNOW. SOME OF THE SHORT TERM
GUIDANCE IS SUGGESTING THAT THE SNOW SHOULD END AT RST BY MID
AFTERNOON...POSSIBLY AS WELL AT LSE. HOWEVER...AN IFR CLOUD DECK
SHOULD HOLD ON THROUGH 00Z...SO HAVE HELD ONTO THE LOW CONDITIONS
GOING THROUGH THE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 PM CST THU JAN 19 2012
WI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR
WIZ041>044-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
MNZ086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1119 AM MST WED JAN 18 2012
.UPDATE...HIGH WINDS MAINLY ON TRACK FOR TODAY. THICKER CLOUD
COVER THIS MORNING HAS DELAYED THE ONSET OF WINDS IN SOME
LOCATIONS BY INHIBITING MIXING AT THE SURFACE. CLOUDS HAVE STARTED
TO THIN AS THE SUBSIDENCE SIDE OF THE JET MOVES ACROSS THE AREA.
THE LACK OF SURFACE HEATING THIS MORNING DOES BRING SOME QUESTION
AS TO HOW FAR EAST THE STRONGER WINDS WILL MAKE IT...ALTHOUGH
STARTING TO SEE SITES IN WESTERN NEBRASKA GUSTING OVER 40 MPH AS
OF 18Z. MOST LIKELY NEBRASKA ZONES WILL ONLY SEE A BRIEF PERIOD OF
MARGINAL WIND WARNING CONDITIONS. FARTHER WEST...FREQUENT GUSTS
OVER 60 MPH OCCURRING OVER MUCH OF SOUTHEAST WYOMING. AS FEW
LOCATIONS HAVE GUSTED TO 70 TO 80 MPH IN THE WIND PRONE AREAS.
WINDS WILL DECREASE ACROSS THE PLAINS TONIGHT AS AN ARCTIC COLD
FRONT BACKS INTO THE AREA. WINDS WILL REMAIN ELEVATED TONIGHT INTO
THE WIND PRONE LOCATIONS.
&&
.AVIATION...18Z TAF ISSUANCE...VERY WINDY CONDITIONS AND SCT TO BKN MID
LEVEL CLOUD DECK WILL CONTINUE THROUGH THE EARLY EVENING TIMEFRAME
ACROSS SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE.
SLIGHTLY DIMINISHED WINDS WILL OCCUR AFTER SUNSET...BUT THEN WILL
RAMP UP AGAIN OVERNIGHT AND CONTINUE THROUGH MIDMORNING ACROSS
SOUTHEAST WYOMING SITES. A COLD FRONT WILL ATTEMPT TO BACK INTO
THE NEBRASKA PANHANDLE FROM THE NORTHEAST THIS EVENING AND
OVERNIGHT...WITH MVFR CIGS POSSIBLE. WINDS WILL SHIFT TO THE NORTH
AND NORTHEAST BEHIND THE FRONT AS WELL...BUT WILL THEN BACK TO THE
WEST AS THE FRONT IS PUSHED EAST BY RESURGING WEST WINDS THROUGH
THE MORNING. SNOW SHOWER ACTIVITY WILL INCREASE ACROSS THE
MOUNTAINS THIS AFTERNOON AND WILL CONTINUE THROUGH TOMORROW. A FEW
SHOWERS COULD MOVE OFF THE TERRAIN TOWARD KRWL AND KLAR...BUT WILL
KEEP WITH VCSH FOR NOW AS CONFIDENCE IS MARGINAL WHETHER THESE
TERMINALS WILL SEE SHOWERS MOVE OVERHEAD. MVFR TO IFR CONDITIONS
CAN BE EXPECTED WITH THE SNOW SHOWERS...AND THE MOUNTAINS WILL
REMAIN OBSCURED THROUGH THE PERIOD. IN ADDITION...MODERATE
MOUNTAIN WAVE ACTIVITY WILL MAINTAIN MODERATE TO STRONG TURBULENCE
ACROSS THE FORECAST AREA THROUGH TOMORROW. RJM
&&
SHORT TERM...TODAY THROUGH FRIDAY NIGHT... IMPRESSIVE HIGH WIND
EVENT STILL ON TRACK FOR TODAY. WINDS HAVE BEGUN TO INCREASE OVER
THE LAST FEW HOURS IN THE ARLINGTON HIGH WIND CORRIDOR...WITH
GUSTS 60 TO 70 KTS BEING REPORTED. THE MEDICINE BOW PROFILER SHOWS
700MB WINDS AROUND 70 KTS...WHICH HAS BEEN ON THE INCREASE THROUGH
THE OVERNIGHT HOURS. THE RUC ANALYZES THE UPPER LEVEL JET AXIS
PASSING OVER SOUTHEAST WY RIGHT NOW...MEANING THE CWA WILL BE IN
THE RIGHT EXIT REGION OF THE JET THROUGH THE AFTERNOON WITH LARGE
SCALE SUBSIDENCE. THIS SUBSIDENCE COMBINED WITH FCSTED 700 MB
WINDS OF 75 KTS AND A STRONG SFC PRESSURE GRADIENT WILL PRODUCE
VERY STRONG WINDS ACROSS THE LOWER ELEVATIONS THROUGH THIS
EVENING. BUFKIT SOUNDINGS AT KSNY AND KBFF SUPPORT GUSTS TO 60 MPH
DURING THE AFTN MIXING. WITH THE LARGE SCALE SUBSIDENCE MOVING
EAST...WINDS WILL BEGIN TO DECREASE DURING THE EVENING ACROSS THE
LOWER ELEVATIONS. HOWEVER...THE WRKHGT PRODUCT SHOWS THE 700MB
CAG-CPR GRADIENT REMAINING ABOVE 75 METERS THROUGH 00Z FRI...SO
THE WIND PRONE AREAS OF ARLINGTON...BORDEAUX...AND THE SOUTH
LARAMIE RANGE WILL CONTINUE TO EXPERIENCE STRONG WINDS THROUGH
THURSDAY. NEXT POTENTIAL HIGH WIND EVENT FOR THE WIND PRONE AREAS
LOOKS TO BE FRI AFTN AS THE NEXT SHORTWAVE IN THE FAST WESTERLY
MIDLEVEL FLOW MOVES OVER WY. MAIN DIFFERENCE BETWEEN TODAY`S EVENT
AND FRI IS THE UPPER LEVEL JET IS FCSTED OVER CO ON FRI...WITH
LARGE SCALE RISING MOTION OVER THE CWA. THUS...NOT EXPECTING AREAS
OUTSIDE THE WIND PRONE AREAS TO REACH HIGH WIND CRITERIA AT THIS
TIME.
NEXT WEATHER CONCERN IS THE OROGRAPHIC SNOWS EXPECTED OVER THE
SIERRA MADRE AND SNOWY RANGES STARTING THIS EVENING AND LASTING
THROUGH FRI. THE SHORT RANGE MODELS ARE IN AGREEMENT IN SHOWING
PERSISTENT MOIST WESTERLY TO NORTHWESTERLY FLOW SLAMMING INTO THE
MOUNTAINS. LOOKS LIKE SNOWFALL RATES WILL BE GREATEST ON FRI AS QG
LIFT ASSOCIATED WITH THE SHORTWAVE INTERACTS WITH THE MOIST FLOW.
FOR SNOWFALL AMOUNTS...WENT CLOSER TO THE NAM DEPICTION OF HIGHER
AMOUNTS DUE TO OROGRAPHIC ENHANCEMENT...WITH A TOTAL OF 12 TO 18
INCHES OVER THE PERIOD FROM THIS EVENING THROUGH FRI. WOULD NOT BE
SURPRISED TO SEE AMOUNTS APPROACHING TWO FEET ON THE WESTERN SLOPES
OF THE SIERRA MADRE RANGE. UPGRADED THE WINTER STORM WATCH TO A
WARNING DUE TO THE ABOVE CONSIDERATIONS.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
THE 00Z MEDIUM RANGE MODEL SUITES ARE CONSISTENT IN PLACING AN
UPSTREAM REX BLOCK NR THE BERING SEA/ALEUTIAN CHAIN THIS WEEKEND.
THIS WILL RESULT IN THE CONTINUATION OF THE PERSISTENT PROGRESSIVE
PATTERN IMPACTING MUCH OF THE LOWER 48. THE MAIN IMPACT LOCALLY IN
THIS PATTERN WILL CONTINUE TO BE OROGRAPHICALLY ENHANCED SNOW ACROSS
THE SNOWY/SIERRA MADRE RANGES AS WELL AS BREEZY TO LOCALLY WINDY
CONDITIONS IN THE ADJACENT FOOTHILLS/PLAINS. AFTER A DRY START TO
THE DAY ON SATURDAY...THE FIRST OF A SERIES OF PV ANOMALIES WILL
MOVE THROUGH THE CWA. AS A RESULT...SNOW WILL AGAIN DEVELOP OVER THE
SNOWY/SIERRA MADRE RANGES. LLVL GRADIENTS CLIMB ABOVE CRITICAL
THRESHOLDS ON SATURDAY AND SATURDAY NIGHT AS WELL...SO MORE
BREEZY/LOCALLY WINDY CONDITIONS CAN BE EXPECTED AT ARLINGTON...
BORDEAUX AND THE SOUTHERN LARAMIE RANGE. THE JET STRUCTURE REMAINS
ZONAL AND TO THE SOUTH...WHICH WILL BE LESS FAVORABLE FOR THESE
STRONG WINDS TO SPREAD TO OTHER AREAS. ANOTHER PV ANOMALY WILL
TRAIL THROUGH ON SUNDAY AS WELL BRINGING ANOTHER ROUND OF SNOW TO
THE SNOWY/SIERRA MADRES. PRECIPITATION CHANCES WILL NOT BE ALL
THAT GREAT OUTSIDE OF THE MOUNTAINS...ALTHOUGH A PERIOD OF LIGHT
SNOW WILL BE POSSIBLE ACROSS LOWER ELEVATIONS OF CARBON COUNTY
FROM TIME TO TIME. MORE SIGNIFICANT SNOW ACCUMULATIONS WILL BE
POSSIBLE FROM THIS EVENT FOR THE SNOWY/SIERRA MADRE RANGES. MEDIUM
RANGE MODEL OUTPUT IS BECOMING INCREASINGLY CONGRUENT ON A SPLIT
FLOW PATTERN EARLY NEXT WEEK...BUT TIMING DIFFERENCES BEGIN TO
CREEP IN. THE GFS IS SLOWER IN CLOSING OFF THE SOUTHERN ENERGY IN
THE SPLIT FLOW AND IS FASTER IN MOVING THE NORTHERN STREAM INTO
THE PLAINS. IN EITHER CASE...DO NOT ANTICIPATE MUCH IN
PRECIPITATION CHANCES OUTSIDE OF THE MOUNTAINS DURING THIS PERIOD.
SATURDAY AND SUNDAY WILL BE THE WARMEST DAYS OF THE EXTENDED WITH
HIGHS CLIMBING INTO THE 30S/40S WEST OF THE LARAMIE RANGE AND
40S/50S EAST. HIGH TEMPERATURES WILL BE COOLER WITH A FROPA
ANTICIPATED THE FIRST OF NEXT WEEK. AS A RESULT...HIGH
TEMPERATURES WILL FALL INTO THE 30S AND 40S EVERYWHERE.
FIRE WEATHER...
STRONG WINDS WILL OCCUR OVER MOST OF SOUTHEAST WYOMING AND THE
WESTERN NEBRASKA PANHANDLE THROUGH THIS EVENING. SUSTAINED WINDS
35 TO 45 MPH WITH GUSTS TO 70 MPH ARE POSSIBLE THIS AFTERNOON. MINIMUM
AFTERNOON RELATIVE HUMIDITY VALUES WILL GENERALLY BE ABOVE 25
PERCENT FOR THE LOW ELEVATIONS EAST OF THE LARAMIE RANGE. WINDS
WILL BEGIN TO DECREASE THIS EVENING BUT REMAIN BREEZY TO WINDY
THROUGH THURSDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 6 PM WEDNESDAY FOR WYZ101-WYZ102-WYZ103-
WYZ104-WYZ105-WYZ107-WYZ108-WYZ109-WYZ112-WYZ113-WYZ114-
WYZ115-WYZ118-WYZ119.
WINTER STORM WARNING FROM 6 PM WEDNESDAY TO 6 PM FRIDAY FOR
WYZ112-WYZ114.
HIGH WIND WARNING UNTIL NOON THURSDAY FOR WYZ106-WYZ110-WYZ116-
WYZ117.
NE...WIND ADVISORY UNTIL 6 PM WEDNESDAY FOR NEZ002-NEZ003-NEZ095.
HIGH WIND WARNING UNTIL 6 PM WEDNESDAY FOR NEZ019-NEZ020-NEZ021-
NEZ054-NEZ055-NEZ096.
&&
$$
UPDATE...LIEBL
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...HAHN
AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
457 AM MST WED JAN 18 2012
.AVIATION...12Z TAF ISSUANCE...
THE PRIMARY AVIATION CONCERN WILL BE THE VERY STRONG WEST WINDS
THAT WILL OCCUR AT AREA TERMINALS TODAY. WIND GUSTS WILL CLIMB
INTO THE 40 TO 55 KNOT RANGE ESPECIALLY LATE THIS MORNING THROUGH
THE AFTERNOON. THESE VERY STRONG WINDS WILL CAUSE SIGNIFICANT
TURBULENCE ACROSS ALL OFF SOUTHEAST WYOMING AND THE WESTERN
NEBRASKA PANHANDLE TODAY. OTHERWISE EXPECT GENERALLY VFR
CONDITIONS TO PREVAIL AT MOST AREA AIRFIELDS WITH SCT-BKN MID-
LEVEL CLOUD DECK. IFR/MVFR CONDITIONS CAN BE EXPECTED AT KRWL THIS
EVENING...WITH EVEN SOME LIGHT SNOW SHOWERS POSSIBLE. AM NOT
CONFIDENT THAT SNOW COVERAGE WILL BE ALL THAT GREAT...SO ONLY
INCLUDED VCSH FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 345 AM MST WED JAN 18 2012/
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
IMPRESSIVE HIGH WIND EVENT STILL ON TRACK FOR TODAY. WINDS HAVE
BEGUN TO INCREASE OVER THE LAST FEW HOURS IN THE ARLINGTON HIGH
WIND CORRIDOR...WITH GUSTS 60 TO 70 KTS BEING REPORTED. THE
MEDICINE BOW PROFILER SHOWS 700MB WINDS AROUND 70 KTS...WHICH HAS
BEEN ON THE INCREASE THROUGH THE OVERNIGHT HOURS. THE RUC ANALYZES
THE UPPER LEVEL JET AXIS PASSING OVER SOUTHEAST WY RIGHT
NOW...MEANING THE CWA WILL BE IN THE RIGHT EXIT REGION OF THE JET
THROUGH THE AFTERNOON WITH LARGE SCALE SUBSIDENCE. THIS SUBSIDENCE
COMBINED WITH FCSTED 700 MB WINDS OF 75 KTS AND A STRONG SFC
PRESSURE GRADIENT WILL PRODUCE VERY STRONG WINDS ACROSS THE LOWER
ELEVATIONS THROUGH THIS EVENING. BUFKIT SOUNDINGS AT KSNY AND KBFF
SUPPORT GUSTS TO 60 MPH DURING THE AFTN MIXING. WITH THE LARGE
SCALE SUBSIDENCE MOVING EAST...WINDS WILL BEGIN TO DECREASE DURING
THE EVENING ACROSS THE LOWER ELEVATIONS. HOWEVER...THE WRKHGT
PRODUCT SHOWS THE 700MB CAG-CPR GRADIENT REMAINING ABOVE 75
METERS THROUGH 00Z FRI...SO THE WIND PRONE AREAS OF
ARLINGTON...BORDEAUX...AND THE SOUTH LARAMIE RANGE WILL CONTINUE
TO EXPERIENCE STRONG WINDS THROUGH THURSDAY. NEXT POTENTIAL HIGH
WIND EVENT FOR THE WIND PRONE AREAS LOOKS TO BE FRI AFTN AS THE
NEXT SHORTWAVE IN THE FAST WESTERLY MIDLEVEL FLOW MOVES OVER WY.
MAIN DIFFERENCE BETWEEN TODAY`S EVENT AND FRI IS THE UPPER LEVEL
JET IS FCSTED OVER CO ON FRI...WITH LARGE SCALE RISING MOTION OVER
THE CWA. THUS...NOT EXPECTING AREAS OUTSIDE THE WIND PRONE AREAS
TO REACH HIGH WIND CRITERIA AT THIS TIME.
NEXT WEATHER CONCERN IS THE OROGRAPHIC SNOWS EXPECTED OVER THE
SIERRA MADRE AND SNOWY RANGES STARTING THIS EVENING AND LASTING
THROUGH FRI. THE SHORT RANGE MODELS ARE IN AGREEMENT IN SHOWING
PERSISTENT MOIST WESTERLY TO NORTHWESTERLY FLOW SLAMMING INTO THE
MOUNTAINS. LOOKS LIKE SNOWFALL RATES WILL BE GREATEST ON FRI AS QG
LIFT ASSOCIATED WITH THE SHORTWAVE INTERACTS WITH THE MOIST FLOW.
FOR SNOWFALL AMOUNTS...WENT CLOSER TO THE NAM DEPICTION OF HIGHER
AMOUNTS DUE TO OROGRAPHIC ENHANCEMENT...WITH A TOTAL OF 12 TO 18
INCHES OVER THE PERIOD FROM THIS EVENING THROUGH FRI. WOULD NOT BE
SURPRISED TO SEE AMOUNTS APPROACHING TWO FEET ON THE WESTERN SLOPES
OF THE SIERRA MADRE RANGE. UPGRADED THE WINTER STORM WATCH TO A
WARNING DUE TO THE ABOVE CONSIDERATIONS.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
THE 00Z MEDIUM RANGE MODEL SUITES ARE CONSISTENT IN PLACING AN
UPSTREAM REX BLOCK NR THE BERING SEA/ALEUTIAN CHAIN THIS WEEKEND.
THIS WILL RESULT IN THE CONTINUATION OF THE PERSISTENT PROGRESSIVE
PATTERN IMPACTING MUCH OF THE LOWER 48. THE MAIN IMPACT LOCALLY IN
THIS PATTERN WILL CONTINUE TO BE OROGRAPHICALLY ENHANCED SNOW ACROSS
THE SNOWY/SIERRA MADRE RANGES AS WELL AS BREEZY TO LOCALLY WINDY
CONDITIONS IN THE ADJACENT FOOTHILLS/PLAINS. AFTER A DRY START TO
THE DAY ON SATURDAY...THE FIRST OF A SERIES OF PV ANOMALIES WILL
MOVE THROUGH THE CWA. AS A RESULT...SNOW WILL AGAIN DEVELOP OVER THE
SNOWY/SIERRA MADRE RANGES. LLVL GRADIENTS CLIMB ABOVE CRITICAL
THRESHOLDS ON SATURDAY AND SATURDAY NIGHT AS WELL...SO MORE
BREEZY/LOCALLY WINDY CONDITIONS CAN BE EXPECTED AT ARLINGTON...
BORDEAUX AND THE SOUTHERN LARAMIE RANGE. THE JET STRUCTURE REMAINS
ZONAL AND TO THE SOUTH...WHICH WILL BE LESS FAVORABLE FOR THESE
STRONG WINDS TO SPREAD TO OTHER AREAS. ANOTHER PV ANOMALY WILL
TRAIL THROUGH ON SUNDAY AS WELL BRINGING ANOTHER ROUND OF SNOW TO
THE SNOWY/SIERRA MADRES. PRECIPITATION CHANCES WILL NOT BE ALL
THAT GREAT OUTSIDE OF THE MOUNTAINS...ALTHOUGH A PERIOD OF LIGHT
SNOW WILL BE POSSIBLE ACROSS LOWER ELEVATIONS OF CARBON COUNTY
FROM TIME TO TIME. MORE SIGNIFICANT SNOW ACCUMULATIONS WILL BE
POSSIBLE FROM THIS EVENT FOR THE SNOWY/SIERRA MADRE RANGES. MEDIUM
RANGE MODEL OUTPUT IS BECOMING INCREASINGLY CONGRUENT ON A SPLIT
FLOW PATTERN EARLY NEXT WEEK...BUT TIMING DIFFERENCES BEGIN TO
CREEP IN. THE GFS IS SLOWER IN CLOSING OFF THE SOUTHERN ENERGY IN
THE SPLIT FLOW AND IS FASTER IN MOVING THE NORTHERN STREAM INTO
THE PLAINS. IN EITHER CASE...DO NOT ANTICIPATE MUCH IN
PRECIPITATION CHANCES OUTSIDE OF THE MOUNTAINS DURING THIS PERIOD.
SATURDAY AND SUNDAY WILL BE THE WARMEST DAYS OF THE EXTENDED WITH
HIGHS CLIMBING INTO THE 30S/40S WEST OF THE LARAMIE RANGE AND
40S/50S EAST. HIGH TEMPERATURES WILL BE COOLER WITH A FROPA
ANTICIPATED THE FIRST OF NEXT WEEK. AS A RESULT...HIGH
TEMPERATURES WILL FALL INTO THE 30S AND 40S EVERYWHERE.
&&
.FIRE WEATHER...
STRONG WINDS WILL OCCUR OVER MOST OF SOUTHEAST WYOMING AND THE
WESTERN NEBRASKA PANHANDLE THROUGH THIS EVENING. SUSTAINED WINDS
35 TO 45 MPH WITH GUSTS TO 70 MPH ARE POSSIBLE THIS AFTERNOON. MINIMUM
AFTERNOON RELATIVE HUMIDITY VALUES WILL GENERALLY BE ABOVE 25
PERCENT FOR THE LOW ELEVATIONS EAST OF THE LARAMIE RANGE. WINDS
WILL BEGIN TO DECREASE THIS EVENING BUT REMAIN BREEZY TO WINDY
THROUGH THURSDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 6 PM WEDNESDAY FOR WYZ103-WYZ104-WYZ105-
WYZ107-WYZ109-WYZ112-WYZ113-WYZ114-WYZ115-WYZ118.
WINTER STORM WARNING FROM 6 PM WEDNESDAY TO 6 PM FRIDAY FOR
WYZ112-WYZ114.
HIGH WIND WARNING UNTIL NOON THURSDAY FOR WYZ106-WYZ110-WYZ116-
WYZ117.
HIGH WIND WARNING FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR
WYZ101-WYZ102-WYZ108-WYZ119.
NE...WIND ADVISORY FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR NEZ002-
NEZ003-NEZ095.
HIGH WIND WARNING FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR
NEZ019-NEZ020-NEZ021-NEZ054-NEZ055-NEZ096.
&&
$$
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM/AVIATION...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
345 AM MST WED JAN 18 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
IMPRESSIVE HIGH WIND EVENT STILL ON TRACK FOR TODAY. WINDS HAVE
BEGUN TO INCREASE OVER THE LAST FEW HOURS IN THE ARLINGTON HIGH
WIND CORRIDOR...WITH GUSTS 60 TO 70 KTS BEING REPORTED. THE
MEDICINE BOW PROFILER SHOWS 700MB WINDS AROUND 70 KTS...WHICH HAS
BEEN ON THE INCREASE THROUGH THE OVERNIGHT HOURS. THE RUC ANALYZES
THE UPPER LEVEL JET AXIS PASSING OVER SOUTHEAST WY RIGHT
NOW...MEANING THE CWA WILL BE IN THE RIGHT EXIT REGION OF THE JET
THROUGH THE AFTERNOON WITH LARGE SCALE SUBSIDENCE. THIS SUBSIDENCE
COMBINED WITH FCSTED 700 MB WINDS OF 75 KTS AND A STRONG SFC
PRESSURE GRADIENT WILL PRODUCE VERY STRONG WINDS ACROSS THE LOWER
ELEVATIONS THROUGH THIS EVENING. BUFKIT SOUNDINGS AT KSNY AND KBFF
SUPPORT GUSTS TO 60 MPH DURING THE AFTN MIXING. WITH THE LARGE
SCALE SUBSIDENCE MOVING EAST...WINDS WILL BEGIN TO DECREASE DURING
THE EVENING ACROSS THE LOWER ELEVATIONS. HOWEVER...THE WRKHGT
PRODUCT SHOWS THE 700MB CAG-CPR GRADIENT REMAINING ABOVE 75
METERS THROUGH 00Z FRI...SO THE WIND PRONE AREAS OF
ARLINGTON...BORDEAUX...AND THE SOUTH LARAMIE RANGE WILL CONTINUE
TO EXPERIENCE STRONG WINDS THROUGH THURSDAY. NEXT POTENTIAL HIGH
WIND EVENT FOR THE WIND PRONE AREAS LOOKS TO BE FRI AFTN AS THE
NEXT SHORTWAVE IN THE FAST WESTERLY MIDLEVEL FLOW MOVES OVER WY.
MAIN DIFFERENCE BETWEEN TODAY`S EVENT AND FRI IS THE UPPER LEVEL
JET IS FCSTED OVER CO ON FRI...WITH LARGE SCALE RISING MOTION OVER
THE CWA. THUS...NOT EXPECTING AREAS OUTSIDE THE WIND PRONE AREAS
TO REACH HIGH WIND CRITERIA AT THIS TIME.
NEXT WEATHER CONCERN IS THE OROGRAPHIC SNOWS EXPECTED OVER THE
SIERRA MADRE AND SNOWY RANGES STARTING THIS EVENING AND LASTING
THROUGH FRI. THE SHORT RANGE MODELS ARE IN AGREEMENT IN SHOWING
PERSISTENT MOIST WESTERLY TO NORTHWESTERLY FLOW SLAMMING INTO THE
MOUNTAINS. LOOKS LIKE SNOWFALL RATES WILL BE GREATEST ON FRI AS QG
LIFT ASSOCIATED WITH THE SHORTWAVE INTERACTS WITH THE MOIST FLOW.
FOR SNOWFALL AMOUNTS...WENT CLOSER TO THE NAM DEPICTION OF HIGHER
AMOUNTS DUE TO OROGRAPHIC ENHANCEMENT...WITH A TOTAL OF 12 TO 18
INCHES OVER THE PERIOD FROM THIS EVENING THROUGH FRI. WOULD NOT BE
SURPRISED TO SEE AMOUNTS APPROACHING TWO FEET ON THE WESTERN SLOPES
OF THE SIERRA MADRE RANGE. UPGRADED THE WINTER STORM WATCH TO A
WARNING DUE TO THE ABOVE CONSIDERATIONS.
.LONG TERM...SATURDAY THROUGH WEDNESDAY...
THE 00Z MEDIUM RANGE MODEL SUITES ARE CONSISTENT IN PLACING AN
UPSTREAM REX BLOCK NR THE BERING SEA/ALEUTIAN CHAIN THIS WEEKEND.
THIS WILL RESULT IN THE CONTINUATION OF THE PERSISTENT PROGRESSIVE
PATTERN IMPACTING MUCH OF THE LOWER 48. THE MAIN IMPACT LOCALLY IN
THIS PATTERN WILL CONTINUE TO BE OROGRAPHICALLY ENHANCED SNOW ACROSS
THE SNOWY/SIERRA MADRE RANGES AS WELL AS BREEZY TO LOCALLY WINDY
CONDITIONS IN THE ADJACENT FOOTHILLS/PLAINS. AFTER A DRY START TO
THE DAY ON SATURDAY...THE FIRST OF A SERIES OF PV ANOMALIES WILL
MOVE THROUGH THE CWA. AS A RESULT...SNOW WILL AGAIN DEVELOP OVER THE
SNOWY/SIERRA MADRE RANGES. LLVL GRADIENTS CLIMB ABOVE CRITICAL
THRESHOLDS ON SATURDAY AND SATURDAY NIGHT AS WELL...SO MORE
BREEZY/LOCALLY WINDY CONDITIONS CAN BE EXPECTED AT ARLINGTON...
BORDEAUX AND THE SOUTHERN LARAMIE RANGE. THE JET STRUCTURE REMAINS
ZONAL AND TO THE SOUTH...WHICH WILL BE LESS FAVORABLE FOR THESE
STRONG WINDS TO SPREAD TO OTHER AREAS. ANOTHER PV ANOMALY WILL
TRAIL THROUGH ON SUNDAY AS WELL BRINGING ANOTHER ROUND OF SNOW TO
THE SNOWY/SIERRA MADRES. PRECIPITATION CHANCES WILL NOT BE ALL
THAT GREAT OUTSIDE OF THE MOUNTAINS...ALTHOUGH A PERIOD OF LIGHT
SNOW WILL BE POSSIBLE ACROSS LOWER ELEVATIONS OF CARBON COUNTY
FROM TIME TO TIME. MORE SIGNIFICANT SNOW ACCUMULATIONS WILL BE
POSSIBLE FROM THIS EVENT FOR THE SNOWY/SIERRA MADRE RANGES. MEDIUM
RANGE MODEL OUTPUT IS BECOMING INCREASINGLY CONGRUENT ON A SPLIT
FLOW PATTERN EARLY NEXT WEEK...BUT TIMING DIFFERENCES BEGIN TO
CREEP IN. THE GFS IS SLOWER IN CLOSING OFF THE SOUTHERN ENERGY IN
THE SPLIT FLOW AND IS FASTER IN MOVING THE NORTHERN STREAM INTO
THE PLAINS. IN EITHER CASE...DO NOT ANTICIPATE MUCH IN
PRECIPITATION CHANCES OUTSIDE OF THE MOUNTAINS DURING THIS PERIOD.
SATURDAY AND SUNDAY WILL BE THE WARMEST DAYS OF THE EXTENDED WITH
HIGHS CLIMBING INTO THE 30S/40S WEST OF THE LARAMIE RANGE AND
40S/50S EAST. HIGH TEMPERATURES WILL BE COOLER WITH A FROPA
ANTICIPATED THE FIRST OF NEXT WEEK. AS A RESULT...HIGH
TEMPERATURES WILL FALL INTO THE 30S AND 40S EVERYWHERE.
&&
.AVIATION...06Z TAFS
VFR CONDITIONS EXPECTED NEXT 24 HOURS AT ALL SOUTHEAST WYOMING AND
NEBRASKA PANHANDLE. MAJOR IMPACT FOR FLIGHT OPERATIONS WILL BE
STRONG WINDS THROUGH MOST OF THE DAY WEDNESDAY. STRONGEST WINS
EXPECTED AT OUR WYOMING AIRPORTS WHERE GUSTS IN EXCESS OF 50KT
VERY LIKELY. MOST LIKELY TIMES FOR THESE WINDS WILL BE 15Z THROUGH
22Z OR SO.
CLAYCOMB
&&
.FIRE WEATHER...
STRONG WINDS WILL OCCUR OVER MOST OF SOUTHEAST WYOMING AND THE
WESTERN NEBRASKA PANHANDLE THROUGH THIS EVENING. SUSTAINED WINDS
35 TO 45 MPH WITH GUSTS TO 70 MPH ARE POSSIBLE THIS AFTERNOON. MINIMUM
AFTERNOON RELATIVE HUMIDITY VALUES WILL GENERALLY BE ABOVE 25
PERCENT FOR THE LOW ELEVATIONS EAST OF THE LARAMIE RANGE. WINDS
WILL BEGIN TO DECREASE THIS EVENING BUT REMAIN BREEZY TO WINDY
THROUGH THURSDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 6 PM WEDNESDAY FOR WYZ103-WYZ104-WYZ105-
WYZ107-WYZ109-WYZ112-WYZ113-WYZ114-WYZ115-WYZ118.
WINTER STORM WARNING FROM 6 PM WEDNESDAY TO 6 PM FRIDAY FOR
WYZ112-WYZ114.
HIGH WIND WARNING UNTIL NOON THURSDAY FOR WYZ106-WYZ110-WYZ116-
WYZ117.
HIGH WIND WARNING FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR
WYZ101-WYZ102-WYZ108-WYZ119.
NE...WIND ADVISORY FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR NEZ002-
NEZ003-NEZ095.
HIGH WIND WARNING FROM 9 AM WEDNESDAY TO 6 PM WEDNESDAY FOR
NEZ019-NEZ020-NEZ021-NEZ054-NEZ055-NEZ096.
&&
$$
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...HAHN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1224 AM EST FRI JAN 20 2012
.AVIATION..../06Z TAFS/
MVFR DECK TO E-SE OF LM APPEARS TO BE EXPANDING ON SATELLITE
IMAGERY EARLY THIS MORNING. WITH LOW LEVEL FLOW BECOMING
LIGHT/VARIABLE AS HIGH PRESSURE MOVES ACROSS THE AREA EARLY THIS
MORNING...THIS CLOUD DECK MAY NOT FULLY DISSIPATE BEFORE CIGS
LOWER AGAIN IN THE AFTERNOON AS ANOTHER SHRTWV BRINGS WIDESPREAD
ACCUMULATING SNOW BACK INTO NRN INDIANA RESULTING IN IFR/LIFR
CONDITIONS FRI AFTN/EVE.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
SIGNIFICANT SNOW ACCUMULATIONS FRIDAY/FRIDAY NIGHT WILL BE THE MAIN
CONCERN FOR THE SHORT TERM. A WINTER WEATHER ADVISORY WILL BE ISSUED
FOR LATE MORNING FRIDAY THROUGH FRIDAY NIGHT FOR APPROXIMATELY
NORTHERN TWO THIRDS OF THE FORECAST AREA.
ACCUMULATING LIGHT SNOW THIS AFTERNOON HAS SHIFTED WELL SOUTH OF
ROUTE 30 LATE THIS AFTERNOON...AND WILL CONTINUE TO SAG SOUTHWARD
THROUGH THE REMAINDER OF THE LATE AFTERNOON HOURS AS AXIS OF LOW
LEVEL FRONTOGENESIS PUSHES SOUTH OF THE FORECAST AREA. FURTHER TO
THE NORTH...LAKE EFFECT SNOW SHOWERS HAVE BEEN INCREASING IN
INTENSITY WITH FAIRLY STRONG 850 HPA/LAKE DELTA TEMPS ON THE ORDER
OF 20 TO 23 DEGREES. RUC SOUNDINGS SUGGEST A NEARLY ISOTHERMAL LAYER
FROM 850 TO 700 HPA WHICH IS LIMITING DEPTH OF THIS LAKE GENERATED
INSTABILITY WITH LAKE INDUCED EQUILIBRIUM HEIGHTS ON THE ORDER OF
ABOUT 5K FT. ANOTHER NEGATIVE FACTOR POINTING AGAINST SIGNIFICANT
LAKE EFFECT SNOW ACCUMULATIONS IS MUCH DRIER MID LEVEL AIR THAT WAS
WORKED INTO THE SOUTHERN GREAT LAKES REGION BEHIND THE SYSTEM WHICH
BROUGHT THE ACCUMULATING SNOW TODAY. THIS MARGINAL LAKE EFFECT SETUP
WILL CONTINUE FOR MUCH OF THE EVENING AND INTO THE OVERNIGHT...AND A
FEW LOCATIONS MAY PICK UP A HALF INCH TO AN INCH OF ADDITIONAL
ACCUMULATION BEFORE INVERSION HEIGHTS CRASH MORE SUBSTANTIALLY
DURING THE OVERNIGHT HOURS. AREAS AWAY FROM LAKE EFFECT
CLOUDS/PRECIP SHOULD CLEAR THIS EVENING. A WEAKENING GRADIENT WITH
SFC RIDGE AXIS BUILDING IN COMBINED WITH THIS CLEARING SHOULD
ALLOW FOR VERY COLD TEMPS TONIGHT INTO THE SINGLE DIGITS ABOVE
ZERO. SOME INCREASE IN HIGH CLOUDS IS EXPECTED LATE TONIGHT THAT
MAY LEVEL OUT TEMPERATURES AFTER 09Z.
ATTENTION WILL THEN TURN TO WHAT WILL BE A VERY FAST MOVING UPPER
LEVEL SYSTEM THAT IS APPROACHING THE PACIFIC NORTHWEST COAST AT THIS
TIME. LOW LEVEL WINDS WILL BACK SOUTHWESTERLY ON FRIDAY AHEAD OF
THIS TROUGH WHICH WILL SET UP A PERIOD OF INTENSE ISENTROPIC UPGLIDE
FRIDAY AFTERNOON/EARLY EVENING OVER THE SHALLOW RETREATING ARCTIC
AIR MASS. STRONG FRONTOGENETIC FORCING ALSO TO DEVELOP IN THE
850/700 LAYER AS THIS LOW LEVEL FLOW RAMPS UP. 12Z NAM REMAINS A
SLIGHTLY SLOWER AND FURTHER NORTH OUTLIER IN REGARDS TO THIS
SYSTEM...WITH 09Z SREF GENERALLY LENDING SUPPORT TO THE MORE RUN TO
RUN CONSISTENT GFS/ECMWF. GENERALLY UTILIZED A PREDOMINATELY
SREF/GFS/ECMWF BLEND FOR THIS FORECAST WITH A MUCH SMALLER
WEIGHTING TOWARD NAM. PERIOD OF MOST INTENSE SNOWFALL APPEARS TO
BE SHAPING UP IN THE 21Z-03Z TIMEFRAME WITH BEST COLOCATION OF
STRONGER SYNOPTIC LIFT WITH FAVORABLE DENDRITIC GROWTH ZONE.
MODEL QPF FROM 12Z SUITE OF MODELS STILL TEND TO SUPPORT MAINLY
HIGH END ADVISORY LEVEL SNOW ACCUMULATIONS WHEN CONSIDERING
EXPECTED SNOW TO LIQUID RATIOS ON THE ORDER OF 15:1 ACROSS THE
NORTH.
CONCERN WITH THESE TYPE OF INTENSE LOW/MID LEVEL BAROCLINIC ZONES IS
FOR AREAS OF ENHANCED BANDING WHICH COULD PUSH SOME AREAS INTO LOW
END WARNING ACCUMULATIONS. 12Z GFS MODEL CROSS SECTIONS STILL
INDICATE RELATIVELY HIGH STATIC STABILITY ATOP THIS LOW LEVEL
FRONTOGENESIS FORCING WHICH MAY TEND TO DISCOURAGE SMALLER SCALE
INTENSE BANDING...AND A BROADER RESPONSE IN UPWARD VERTICAL MOTION
FIELDS. SYSTEM ALSO WILL BE VERY PROGRESSIVE WITH SOME INDICATIONS
OF ISENTROPIC UPGLIDE WEAKENING SLIGHTLY FROM WEST TO EAST INTO
NORTHEAST INDIANA BY EVENING. TAKING THE ABOVE FACTORS INTO
CONSIDERATION HAVE OPTED TO GO WITH A HIGH END WINTER WEATHER
ADVISORY FOR SNOW ACCUMULATIONS OF 3 TO 7 INCHES NORTHERN TWO
THIRDS...WITH THE HIGHER ACCUMULATIONS EXPECTED FAR NORTHERN
INDIANA/SOUTHERN LOWER MICHIGAN. WINDS NOT EXPECTED TO BE AN OVERLY
HUGE CONCERN WITH THIS SYSTEM...BUT A BRIEF PERIOD IN THE 21Z-03Z
TIMEFRAME OF 1 TO 2 INCH PER HOUR SNOWFALL RATES APPEARS TO BE A
GOOD POSSIBILITY. IN TRENDING MORE TOWARD GFS...HAVE CONFINED MIXED
PRECIP MENTION TO A CHANCE OF SLEET ACROSS THE SOUTH BUT THIS WILL
NEED TO BE WATCHED IN FUTURE FORECASTS ONCE CONFIDENCE IN LOW LEVEL
THERMAL FIELDS INCREASES. SNOW WILL BEGIN TO WANE LATE FRIDAY NIGHT
WITH INDICATIONS OF FAR SOUTHEAST GETTING INTO SOME ENHANCED
SNOWFALL AS A PIECE OF EASTERN PACIFIC SHORT WAVE DIGS MORE
AGGRESSIVELY INTO THE OHIO RIVER VALLEY.
LONG TERM...
SUNDAY THROUGH THURSDAY
SIG PATTERN ADJUSTMENT TO OCCUR IN THE LONG TERM PERIOD AS REX BLOCK
RIDGING SHIFTS WEST OVER ALASKA...WITH SUBSTANTIAL UPPER LEVEL
TROUGHING EXPECTED THERE BY THIS WEEKEND. THIS WILL RESULT IN A
SWITCH BACK TO FAST WESTERLY GENERALLY MILD FLOW...WITH EMBEDDED
FAST MOVING IMPULSES PROVIDING PERIODIC CHANCES FOR RAIN/SNOW. THIS
WILL OCCUR AFTER THE ADVECTION OF A POTENT MID LATITUDE CYCLONE
EARLY NEXT WEEK...A SYSTEM WHICH COULD BRING A SUBSTANTIAL AMOUNT OF
RAIN/WIND/AND EVEN THUNDERSTORMS TO THE AREA SUNDAY NIGHT INTO
MONDAY MORNING. ECMWF/GFS/AND GEFS SOLUTIONS CONTINUE TO REMAIN
NEARLY PHASED PER HEIGHT SOLUTIONS IN THE PERIOD...WITH INCREASED
FORECAST CONFIDENCE IN THE PERIOD.
SAT-MON...FRIDAY SYSTEM WILL BE IN THE PROCESSES OF EXITING THE
REGION WITH A LOW CHANCE FOR LINGERING LIGHT SNOW FAR SE SAT AM.
WEAK SUBSIDENT REGIME WITH SFC RIDGING WILL SUPPORT GRADUAL EROSION
OF LINGERING LOW CLOUDS...WITH WINDS VEERING SE THROUGH THE SAT
PERIOD. MEANWHILE...A SIG MID LEVEL TROUGH IS EXPECTED TO DIG INTO
THE SW CONUS AND BEGIN TO EJECT TOWARD THE REGION. SYSTEM INFLUENCE
TO THE LOCAL AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY
FLOW INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC
ZONE IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE
EJECTING MID LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE
FALLS...SUPPORTING RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL
THETA-E ADV TO ENSUE SUNDAY IN THE REGION WITH SIG SFC LAYER
DEWPOINT RISES INTO SUNDAY NIGHT. STAUNCH LL FLOW WITH A 60 TO 70
KNOT LLJ PROGGED IN THE ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT
DEEP LAYER THETA-E RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A
SATURATED BL WITH DRIZZLE AND FOG EXPECTED TO DEVELOP SUNDAY
AFTERNOON INTO THE EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT.
ECMWF H7-H3 LAYER ANALYSIS REVEALS A RATHER IMPRESSIVE EML WITH
STEEP MID LEVEL LAPSE RATES GIVEN STRONG LOW CENTERED WAA. H85
THETA-E APPROACHES 325K BY LATE SUNDAY NIGHT...WITH SW INDICES
NEGATIVE...INDICATING A GOOD ENVIRONMENT FOR ELEVATED THUNDERSTORMS.
HAVE INTRODUCED A LOW CHANCE THUNDER AT THIS POINT. ALBEIT
SMALL...THERE IS A CONCERN FOR SEVERE WEATHER GIVEN INDICATED H5
JETLET IN EXCESS OF 90 KNOTS...WHICH WOULD BE CAPABLE QLCS JET
DRIVEN CELLS. PERHAPS THE BIGGEST CONCERN ATTM IS FOR INCREASED
FLOODING CONCERNS GIVEN FULL SNOWPACK MELT WITH THE POTENTIAL FOR
HEAVY RAIN. WILL HIGHLIGHT IN AN ESF. NEGATIVE TROUGH TILT INDICATED
IN FORECAST MODELS SUGGEST A NW TRACK ADJUSTMENT PER THE SFC
LOW...WITH A SLOWER SYSTEM ARRIVAL POSSIBLE...IN ADDITION TO WARMER
THERMAL FIELDS. HENCE DROPPED THE SNOW MENTION SUN NIGHT/TRIMMED
MONDAY SNOW MENTION/AND ADJUSTED TEMPS UP. CAA WILL DOMINATE MONDAY
WITH FALLING TEMPS IN THE DAYTIME PERIOD LIKELY. LINGERING LIGHT
SNOW SHOWERS WILL BE POSSIBLE MAINLY NW.
TUE-THUR...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED PERIOD AND HAVE RETAINED POPS THEN...OPTING TO
KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS.
OTHERWISE...ADJUSTED TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY
ONCE AGAIN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 7 AM EST /6 AM CST/ SATURDAY FOR INZ003>009-012-014-
016>018.
MI...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
SATURDAY FOR MIZ077>081.
OH...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
SATURDAY FOR OHZ001-002-004-005-015-016.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
LMZ043-046.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...JT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
220 AM MST FRI JAN 20 2012
.DISCUSSION...
220 AM MST FRI JAN 20 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS CONTINUES TO SHOW LONG
FETCH OF W/NW FLOW ACROSS THE CENTRAL US WITH TROUGH OVER THE
NORTHEAST. AT THE SURFACE A STRONG COLD FRONT CONTINUES TO LINGER
ALONG THE COLORADO/KANSAS STATE LINE WITH A 15-20F SPREAD IN TEMPS
FROM THE EAST TO THE WEST ACROSS THE CWA.
TODAY-SATURDAY...MAIN FOCUS DURING THESE PERIODS CONTINUES TO BE ON
TEMPS ACROSS THE CWA...COMPLICATED BY LINGERING FRONT. THE FRONT IS
EXPECTED TO BEGIN TO LIFT EAST THIS MORNING. WESTERLY FLOW AT THE
SURFACE SHOULD BRING MILD TEMPS INTO THE WESTERN HALF OF THE
CWA...WITH COLD TEMPS LINGER ALL DAY ACROSS THE EASTERN PART OF
THE CWA. A WEAK SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS
LATER TODAY WILL PUSH A REINFORCING SHOT OF COLD AIR SOUTH
TOWARDS THE CWA...RESULTING IN THE COLD FRONT SWINGING BACK
TOWARDS THE W/SW THIS AFTERNOON/EVENING. HIGH TEMPS TODAY MAY BE
REACHED BEFORE NOON OVER CENTRAL PARTS OF THE CWA...WITH A NON-
DIURNAL COOLING TREND POSSIBLE THIS AFTERNOON OVER PARTS OF THE
CWA. CURRENTLY EXPECTING ABOUT A 30F SPREAD IN HIGH TEMPS FROM THE
EAST TO THE WEST...WITH HIGHS NEAR 60F IN EASTERN COLORADO...AND
IN THE UPPER 20S NEAR NORTON. S/SW FLOW DEVELOPS SATURDAY...WHICH
WILL HELP SOUR OUT THE COLDEST AIR FROM MOST OF THE CWA...THOUGH
EASTERN LOCATIONS WILL STILL LIKELY REMAIN BELOW NORMAL.
SUNDAY...A TROUGH DEVELOPING OVER GREAT BASIN WILL PUSH
EAST...WITH THE MEAN TROUGH AXIS OVER WESTERN KANSAS BY 18Z
SUNDAY. LARGE SCALE ASCENT COMBINED WITH INCREASING MOISTURE AHEAD
OF TROUGH AXIS WILL WILL OVERSPREAD CWA SUNDAY MORNING...QUICKLY
PUSHING E/NE OF THE CWA DURING THE AFTERNOON. ECMWF CONTINUES TO
BE THE WETTEST SOLUTION...THOUGH GFS AT LEAST SHOWS SOME SUPPORT
FOR PRECIP IN THE NE CWA. MAIN CHANGE TO PREVIOUS FORECAST WAS TO
BUMP UP POPS UP IN THE N/NE...AND SPEED UP THE EXIT OF PRECIP
DURING THE AFTERNOON FROM THE WEST TO THE EAST. VERY DRY AIR WILL
ADVECT INTO THE CWA FROM THE WEST DURING THE AFTERNOON...WITH
WINDY CONDITIONS DEVELOPING BY MIDDAY. WE MAY NEED TO ISSUE A RED
FLAG WARNING FOR WESTERN PARTS OF THE CWA AND A WIND ADVISORY FOR
THE MAJORITY OF THE CWA...HOWEVER ITS STILL TOO EARLY FOR THIS
FORECAST CYCLE.
DR
FOR THE PERIOD MONDAY THROUGH THURSDAY...A COLD FRONT WILL MOVE
THROUGH THE REGION ON TUESDAY WITH BREEZY NORTHWEST WINDS AND COLDER
TEMPERATURES. MODELS SHOW SOME LIGHT PRECIPITATION WITH THE FRONT
WHICH MAY END UP NOTHING MORE THAN FLURRIES. TEMPERATURES REBOUND
QUICKLY WITH ABOVE NORMAL TEMPERATURES WEDNESDAY AND THURSDAY.
024
&&
.AVIATION...
931 PM MST THU JAN 19 2012
FOR THE 06Z TAFS...VFR THROUGH THE PERIOD. GUSTY WINDS CURRENTLY
AT KGLD WILL SUBSIDE THE NEXT FEW HOURS. A COLD FRONT WILL MOVE
ACROSS THE REGION LATER THIS MORNING WHICH WILL CAUSE WINDS TO
VEER FROM THE SOUTHEAST TO THE NORTHWEST WITH TIME AND BECOME
GUSTY. GUSTS WILL DIMINISH CLOSE TO 00Z. MID/HIGH CLOUDS WILL
CONTINUE TO OVERSPREAD THE REGION WITH BASES 10K-15K FEET.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
153 AM EST FRI JAN 20 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE EAST THROUGH NEW ENGLAND AND THE GULF
OF MAINE OVERNIGHT. LOW PRESSURE WILL SHIFT INTO THE MARITIMES ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. HIGH PRESSURE
WILL SHIFT EAST FRIDAY NIGHT AS WEAK LOW PRESSURE APPROACHES NEW
ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS OUT TO SEA
SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE WILL BUILD IN FROM
THE NORTHWEST SATURDAY NIGHT AND SUNDAY. LOW PRESSURE LIFTING
NORTHEAST OUT OF THE NORTHERN GREAT LAKES WILL DRIVE A COLD FRONT
TOWARD NEW ENGLAND ON MONDAY. THE FRONT WILL CROSS THE AREA MONDAY
NIGHT WITH A TRAILING TROUGH OF LOW PRESSURE MOVING THROUGH THE
REGION ON TUESDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST
ON WEDNESDAY. LOW PRESSURE WILL PASS SOUTH OF NEW ENGLAND ON
THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
2AM UPDATE...
SNOWFALL RATES HAVE INCREASED AS LOW PRESSURE HAS DEVELOPED AND
PUSHED OFFSHORE OF MASSACHUSETTS AND INTO THE GULF OF MAINE. SNOW
RATIOS HAVE BEEN IN THE 15 TO 20 TO 1 RANGE... ALLOWING SNOWFALL
TO PILE UP QUICKLY. HAVE SOME CONCERNS THAT AREAS FROM CENTRAL
CUMBERLAND COUNTY EASTWARD THROUGH ANDROSCOGGIN AND KENNEBEC COUNTY
MAY RECEIVE 6 TO 7 INCHES OF SNOW AS HEAVIER SNOW CONTINUES FOR
THE NEXT SEVERAL HOURS. ONSHORE FLOW CONTINUES TO SLING MORE
MOISTURE INTO WESTERN MAINE... AND IS BEING LIFTED ALONG AND
INLAND OF THE COASTAL FRONT. BIGGEST REASON FOR NOT UPGRADING TO A
WINTER STORM WARNING IS DUE TO THE LIMITED SNOWFALL AMOUNTS THAT
HAVE LIKELY FALLEN SO FAR ACROSS KENNEBEC COUNTY AND EASTWARD. THIS
WILL CHANGE QUICKLY AS HEAVY SNOW MOVES EAST. AT THE OFFICE IN
GRAY 1.8 INCHES FELL BETWEEN MIDNIGHT AND 1AM... FOR A TOTAL OF
AROUND 3 INCHES. EXPECT ANOTHER 3 INCHES TO BE POSSIBLE BEFORE THE
ACCUMULATIONS END. SNOWFALL TOTALS WILL FLIRT WITH THE 6 INCH
WARNING CRITERIA... BUT MAY NOT BE WIDESPREAD ENOUGH FOR AN UPGRADE.
0123Z UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW BANDS OF LIGHT SNOW SHOWERS
MOVING ONSHORE FROM THE GULF OF MAINE THIS EVENING. MUCH OF THIS
PRECIPITATION HAS BEEN VERY LIGHT IN NATURE. MEANWHILE...THE
TIMING OF THE STEADY SNOWFALL ENTERING THE FORECAST AREA IS IN
GOOD AGREEMENT WITH THE SHORT TERM FORECAST FROM THE LATEST HRRR
RUN.
WILL KEEP WINTER WEATHER ADVISORIES IN EFFECT FOR THE SOUTHEASTERN
PORTION OF OUR FORECAST AREA. MUCH OF THE PRECIPITATION ENTERING
THE FORECAST AREA REMAINS LIGHT...HOWEVER THERE SHOULD BE MODERATE
SNOWBANDS EMBEDDED WITHIN THIS PRECIPITATION FIELD AS NOTED
ENTERING THE CT/RI COASTLINE. WITH SURFACE WAVE ALREADY BEGINNING
TO FORM NEAR JFK AT 01Z...IN COMBINATION WITH A BRIEF PERIOD OF
ENHANCED VERITICAL MOTION (INCLUDING THE SNOW GROWTH
REGION)...EXPECT AREAS OF 3-6 INCHES SNOWFALLS SOUTHEASTERN ZONES.
HIGHEST SNOWFALL TOTALS SHOULD BE NEAR THE PENOBSCOT RIVER VALLEY.
PREV UPDATE...
ALSO...LATEST HRRR MODEL UPDATE HAS A GOOD HANDLE WITH OCEAN
EFFECT SNOW SHOWERS ENTERING ROCKINGHAM AND YORK COUNTIES THIS
HOUR. HAVE UPPED POPS QUITE A BIT FOR THIS AREA TO ACCOUNT FOR
THIS LOCAL PCPN. -SHSN WILL SPREAD NORTHWARD IN THE NEXT HOUR OR
TWO INTO THE PWM AND POSSIBLY THE NHZ AREAS.
HAVE UPDATED GRIDS TO INCREASE CLOUD COVER OVERNIGHT TO OVERCAST
CONDITIONS WITH ADVISORIES IN EFFECT. REST OF THE GRIDS WILL
REMAIN RELATIVELY UNCHANGED WITH ADVISORIES CONTINUING FOR THE ERN
HALF OF THE FORECAST AREA.
PREV DISC...
WEAK LOW PRESSURE APPROACHING FROM THE WEST WILL BRING A
BRIEF ROUND OF LIGHT TO MODERATE SNOW TO THE REGION OVERNIGHT. LOW
PRESSURE STILL FORECAST TO RE-DEVELOP OVER SOUTHERN NEW ENGLAND
AND MOVE INTO THE GULF OF MAINE BUT MODELS NOT AS STRONG WITH THIS
SYSTEM TODAY AND QPF FOR THE EVENT HAS DROPPED OFF SOMEWHAT.
EXPECT SNOW TO PUSH INTO THE CONNECTICUT VALLEY EARLY THIS EVENING
AND QUICKLY OVER-SPREAD THE REMAINDER OF THE FORECAST AREA THROUGH
MIDNIGHT. WILL STILL BE GOING WITH THE CURRENT ADVISORIES FOR
SOUTHERN AND COASTAL MAINE EXCLUDING YORK COUNTY FOR THE OVERNIGHT
HOURS. HAVE NOT CHANGED ACCUMULATIONS MUCH FROM YESTERDAY WITH 2
TO 4 INCHES OF ACCUMULATION EXPECTED ACROSS MUCH OF NEW HAMPSHIRE
AND EXTREME SOUTHWEST MAINE. REMAINDER OF SOUTHERN AND COASTAL
MAINE WILL SEE 3 TO 6 INCHES OF SNOWFALL THROUGH EARLY FRIDAY
MORNING. EXPECT SNOW TO QUICKLY END IN NEW HAMPSHIRE AND SOUTHWEST
MAINE BEFORE DAYBREAK ON FRIDAY. SHOULD BE A MUCH WARMER NIGHT
WITH TEMPS IN THE LOWER TO MID TEENS IN THE NORTH AND MID TEENS TO
LOWER 20S IN THE SOUTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/...
HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRINGING CLEARING
SKIES AND MOSTLY SUNNY WEATHER TO MOST OF THE AREA ON FRIDAY.
SHOULD SEE MORNING CLOUDS CLEARING OUT OF THE MOUNTAINS AND FAR
EASTERN ZONES BY NOON. EXPECT TEMPS TO RANGE THROUGH THE TEENS IN
THE NORTH AND THROUGH THE 20S AND LOWER 30S IN THE SOUTH.
MID HIGH LEVEL CLOUDINESS WILL BE ON THE INCREASE FRIDAY NIGHT AS
WEAK OVER-RUNNING PATTERN SHIFTS INTO THE NORTHEAST AHEAD OF LOW
PRESSURE MOVING INTO THE MID ATLANTIC STATES. WILL INTRODUCE
LOW CHANCE POPS INTO SOUTHERN NEW HAMPSHIRE AFTER MIDNIGHT BUT
EXPECT LITTLE IF ANY ACCUMULATION THROUGH SATURDAY MORNING. LOW
TEMPS WILL RANGE FROM ZERO TO 10 BELOW IN THE NORTH AND 5 TO 15
ABOVE IN THE SOUTH.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
MODELS TRACK WEAK SFC LOW OFF THE MID ATLANTIC COAST E AND OUT TO
SEA ON SATURDAY. THIS WILL PRODUCE -SN ACROSS THE FCST AREA WITH
LGT ACCUMULATIONS PSBL. HIGHEST CHC OF SN AND HIGHEST
ACCUMULATIONS OVER MORE SRN AREAS CLOSER TO THE LOW WITH LOWEST
CHC AND ACCUMULATION TO THE N. VERTICAL TEMP PROFILE CD ENOUGH TO
SUPPORT ALL SN FOR THIS EVENT.
THE LOW MOVES OUT TO SEA FAIRLY QUICKLY WITH -SN ENDING FROM W TO E
IN THE AFTERNOON. HIGH PRES FOLLOWS WITH FAIR WX SATURDAY NGT AND
SUNDAY. THE HIGH MOVES OUT TO THE E SUNDAY NGT AS THE UPR LVL
RIDGE CRESTS ALONG THE E COAST. A STRONG UPR LVL CUTOFF SYSTEM
OVER THE UPPER MID WEST CREATES A FAIRLY STRONG SFC LOW OVER THE
GREAT LAKES THAT WILL TRACK SLOWLY E WITH A TRAILING CD FNT
EXTENDING TO THE S. AHEAD OF THIS SYSTEM INCREASING S SW FLOW FROM
SFC TO H5 BRINGS IN MUCH WARMER AIR ALOFT AND EVENTUALLY TO THE
SFC AS PRCP EVENTUALLY MOVES IN LATE SUNDAY NGT AND MONDAY. MAY BE
SOME -SN OR MIXED SN AND ICE TO BEGIN WITH BUT GRADUALLY PRPC
CHANGES OVER TO RA FOR MONDAY AND MONDAY NGT THOUGH SOME -FZRA
STILL PSBL ACROSS THE NRN TIER OF ZONES WHERE IT WILL TAKE THE
LONGEST TO SCOUR OUT THE CD AIR AT THE SFC.
THE CD FNT MOVES THRU BY TUESDAY MORNING WITH COLDER AIR FOLLOWING
THE FNT AS TEMPS LIKELY TO FALL DURING THE DAY AFTER MILD PREDAWN
READINGS. A SECONDARY UPR LVL TROF MOVES THRU WHICH MAY PRODUCE A
FEW -SHSN BUT THE N/MT ZONES HAVE THE BEST CHC OF -SHSN DUE TO
DEVELOPING UPSLOPE FLOW IN THE CD AIR ADVECTION BEHIND THE FNT.
HIGH PRES BRINGS FAIR WX WEDNESDAY FOLLOWED BY A FAST MOVING SFC
LOW THAT WILL TRACK TO OUR S BRINGING THE CHC OF -SN WEDNESDAY NGT
AND THURSDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SATURDAY
THRU SATURDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST...
EXCEPT USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN
TEMPS.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...MVFR/IFR CEILINGS AND VSBY DEVELOPING THIS
EVENING...IMPROVING TO VFR ON FRIDAY. VFR FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...IFR PSBL WITH -SN SATURDAY.
IFR OR LIFR PSBL WITH MIXED PRCP DEVELOPING LATE SUNDAY NGT AND
CONTINUING THRU MONDAY.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY IN EFFECT THIS EVENING THROUGH FRIDAY.
LONG TERM /SATURDAY THROUGH MONDAY/...CONDITIONS BELOW SCA LEVELS
SATURDAY THRU SUNDAY NGT...THEN INCREASE TO SCA LEVELS OR PSBL
GALES MONDAY INTO MONDAY NGT IN STRENGTHEN S SW FLOW AHEAD OF THE
CD FNT. WINDS SHIFT TO THE W AS THE FNT MOVES OUT TO SEA AND CONT AT
SCA OR PSBL GALE LEVELS ON TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR
MEZ012>014-019>022-024>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ150>154.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
358 AM CST Fri Jan 20 2012
.DISCUSSION...
Forecast challenges continue aplenty thanks to the many shortwaves
within the prevailing zonal flow that is currently dominating the
nation. Water vapor imagery from early this morning shows one of the
shortwaves of note, shifting through the central Rockies, accompanied
by a fair amount of mid and high level Pacific moisture, as noted by
the cloud cover spilling over the continental divide. Another
shortwave that will be effecting our weather over the Sunday/Monday
periods is noted shifting through the eastern Pacific under a low
anchored in the Gulf of Alaska. Closer to home, a cold surface high
is seen shifting from the Northern Plains into the Great Lakes.
For today, verity of models all advertise that the shortwave
shifting through the Rocky Mountains will continue due east across
the Central and Northern Plains States today, undergoing only minor
amplification as it crosses the Nation. Isentropic lift on surfaces
from 280K and up has already begun to result in bands of snow across
western Iowa this morning. This activity is expected to shift off to
the east through the day along with the parent shortwave. A dry
easterly surface wind should limit how far south the snow will
settle as top down saturation through the dry boundary layer will be
difficult, but not impossible. Have kept a modest chance of snow and
flurries for today along the Iowa border as a result. Otherwise, low
clouds could be an issue farther south as a weak inverted trough
tries to focus some moisture along the backside of the exiting
surface high. Some fleeting sprinkles or - if cold enough - flurries
could fall from the clouds as far south as central Missouri today as
a result, though have opted not to include in the forecast at this
time owing to the low potential.
For the weekend, it looks like a bit of a roller coaster ride for
our temperatures, among other things. Saturday, temperatures will
stay around to below normal as another cold surface high oozes
through the region behind the shortwave bringing snow to Iowa
today. However, our attention then turns towards the East Pacific
shortwave, and Sunday. At this time, both mid and short range models
advertise the Pacific shortwave amplifying as it cross the United
States, allowing a quick return flow to spread into the Southern and
Central Plains. This will result in our jumping from below normal
temperatures Saturday, to above normal temperatures Sunday. The
accompanying moisture return will also result in the potential for
more precipitation during the afternoon and overnight hours of
Sunday.
Looking at next work week, mid range models continue to hint at
another amplifying shortwave moving across the nation. Confidence in
any particular solution is a bit low, but the consensus is
sufficient to warrant keeping some POPs in for Tuesday into
Wednesday, with the emphasis on Tuesday night.
Cutter
&&
.AVIATION...
For the 06z TAF...Will continue VFR conditions overnight but changes
now considered after 12z Friday. Short range models, NAM/GFS Bufr
and RUC soundings now more adamant that MVFR cigs will develop
around sunrise Friday over northwest MO as an inverted surface trof
extends through west central MO. With an east to ese boundary layer
wind this sets up the potential for warm air advection which would
allow the stratus deck to form. Confidence has improved enough to
warrant adding MVFR cigs until the inverted surface trough is pushed
east in the afternoon in response to a fast moving shortwave
streaking through KS. Should see drier air/subsidence flow back into
the terminals after sunset which should scatter out the stratus deck
leaving VFR conditions for tomorrow night.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1132 PM CST THU JAN 19 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
/305 PM CST THU JAN 19 2012/
High momentum quasi-zonal flow will persist across the conus through
the weekend, becoming more amplified yet still in a progressive
state by Sunday. Shortwave trough and attendant rich Pacific
moisture source affecting the Pacific NW today will shear eastward
across the Rockies inducing weak lee cyclogenesis Friday with a
modified boundary layer return flow pulling into the mid Mississippi
River valley. The vast majority of elevated waa and top down
saturation via Pacific moisture should be relegated to the I-80
corridor and points north, though flurries/light snow could
potentially affect far northern/northeast Missouri as weak
uvv/isentropic ascent in the cold cloud bearing layer supportive for
ice crystal growth clip this region. Overall, would expect little if
any accumulation.
Will also need to watch trajectories of return flow from the south
and the potential for extensive low clouds and drizzle through a
largely part of the cwa. Am quite skeptical of model moisture
profile initializations this morning; and consequently this leads to
higher uncertainty regarding any saturation in the boundary layer
Friday morning. NAM-WRF is most aggressive with low clouds north of
a developing warm front, with other models only partially becoming
saturated. Feel central Missouri stands the best chance for low
clouds and possible some drizzle, yet sounding profiles are not
quite indicative of drizzle. Further west, more veered wind profiles
just below the H8 inversion layer suggest drier air precluding
saturation. Have hedged towards the drier solutions feeling modeled
soil/atmosphere interface is too cold and saturated versus reality.
Nevertheless, with or without low clouds, more extensive mid/high
clouds streaming over the Rockies should limit overall insolation,
and have kept forecast temps near a model blend around climatology,
or about a category lower than previously advertised.
Dry and cool high pressure will maintain its influence over the
region on Saturday insuring temperatures once again near or slightly
below the climatological average. Renewed stronger lee cyclogenesis
late Saturday afternoon will allow sfc winds to back around to a sly
direction, strengthening through the evening and overnight hours.
Thus, expect temperatures to actually begin to rise not long after
sunset Saturday into Sunday morning.
21
Sunday - Wednesday:
Models continue to struggle with the timing and intensity of a
system for the early part of next week. However there has been
increased consistency for a few runs in bringing the system into the
area Sunday into Monday. Both the ECMWF and the GFS show a rather
strong wave moving through the Central Plains Sunday and this has
some support from the GFS ensemble mean and the ECMWF ensemble mean.
The GEM looks to be a bit too fast compared to the other models but
also moves a wave through the area Sunday. The placement of the wave
from the current suite of models brings the main energy associated
with the system a bit further north but again there is agreement
amongst the deterministic models and their ensemble partners. With
the placement possibly a bit further north and with the wave
currently looking rather robust, have increased temperatures for
Sunday. There is the potential to see temperatures in the 60s for at
least southern zones but if trends continue we could see more
widespread 60+ degree readings. In fact, if this were springtime and
not mid January the warm sector dynamics would be fairly conducive
for severe weather. Fortunately it is still January and it should
just lead to a warm and windy day with perhaps a few showers during
the afternoon before the system lifts away and temperatures begin to
drop on the backside of the low. Models produce a well pronounced
deformation area which for now would affect mainly northern Kansas
through Nebraska and Iowa. Some wrap around precipitation is likely
though, given current forecast track and as cold air advects into
the region, in the wake of the departing low, a transition to some
light snow is expected. This should mainly impact northern Missouri.
Models show another wave entering the region Wednesday into Thursday
but the GFS seems too intense with its QPF given that the wave tries
to split into a northern stream wave and southwestern closed low.
Given this have eased up on POPs for the middle of the week which
were fairly heavily influenced by the going forecast and the and GFS.
CDB
&&
.AVIATION...
For the 06z TAF...Will continue VFR conditions overnight but changes
now considered after 12z Friday. Short range models, NAM/GFS Bufr
and RUC soundings now more adamant that MVFR cigs will develop
around sunrise Friday over northwest MO as an inverted surface trof
extends through west central MO. With an east to ese boundary layer
wind this sets up the potential for warm air advection which would
allow the stratus deck to form. Confidence has improved enough to
warrant adding MVFR cigs until the inverted surface trough is pushed
east in the afternoon in response to a fast moving shortwave
streaking through KS. Should see drier air/subsidence flow back into
the terminals after sunset which should scatter out the stratus deck
leaving VFR conditions for tomorrow night.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
348 AM EST FRI JAN 20 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SNOW SQUALLS TO THE REGION TONIGHT AND
EARLY FRIDAY MORNING. FRIDAY NIGHT, A STRONGER STORM WILL MOVE
THROUGH THE MID ATLANTIC STATES. THIS STORM WILL BRING MODERATE
ACCUMULATING SNOW TO THE SOUTHERN TIER AND CATSKILLS OF NEW YORK,
AND NORTHEASTERN PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 PM UPDATE...SOME BIG CHANGES WITH THIS UPDATE. FIRST OFF...WE
GOT A REPORT OF 8" OF SNOW IN BOONVILLE FROM A SPOTTER THROUGH
FACEBOOK. WE CONFIRMED THIS AMOUNT WITH A FEW REPORTS OF AROUND 6"
IN THE SAME AREA. WITH CRITERIA FOR A WARNING BEING 7" IN 12 HOURS
OR 9" IN 24 HOURS...AND EXPECTING MORE SNOW DUE TO LAKE EFFECT
LATER TONIGHT...AN UPGRADE TO A WARNING WAS AN EASY CALL. TOUGHER
CALL ON WHAT TO CALL IT (LAKE EFFECT VS. WINTER STORM). AFTER
COORDINATION WITH BUFFALO AND ALBANY...DECIDED TO GO THE WINTER
STORM ROUTE SINCE THIS WOULD BE AN UPGRADE FROM THE ADVISORY WE
ALREADY HAD OUT...AND JUST MENTION THE TRANSITION TO LAKE EFFECT
SNOW IN THE PRODUCT ITSELF. FARTHER SOUTH AND EAST...AN AREA OF
SNOW HAS PRODUCED 1 TO 3 INCHES OF SNOW IN ISOLATED AREAS OF
CORTLAND...CHENANGO...BROOME...DELAWARE COUNTIES ALONG WITH SOME
OF NEPA. THIS IS IN ASSOCIATION WITH THE LEFT EXIT REGION OF A
JET. THESE AREAS MAY APPROACH 4" IN ISOLATED AREA WITH ANOTHER
INCH EXPECTED OVERNIGHT FROM A SQUALL LINE...BUT THE AVERAGE FOR
THIS WHOLE AREA WILL BE CLOSER TO 1 TO 2 INCHES...THUS NO
ADVISORY WILL BE ISSUED.
LAST BUT NOT LEAST...THE SQUALL LINE WE HAVE BEEN TRACKING IS NOW
MOVING THROUGH CENTRAL NY. THE LINE HAS HELD TOGETHER QUITE NICELY
AND WE STILL EXPECT A QUICK HALF TO 1.5 INCHES OF SNOW IN A BURST.
WE CONTINUE TO STRESS THAT THESE AMOUNTS ARE NOT HIGH BUT WILL
CREATE SLICK TRAVEL IN A SHORT PERIOD OF TIME. THE PREVIOUS AFD IS
BELOW...
730 PM UPDATE...THE FORECAST IS IN PRETTY GOOD SHAPE. SOME SNOW
HAS DEVELOPED NEAR THE BINGHAMTON AND NORWICH AREAS RECENTLY. THIS
IS RESPONSE TO A JET STREAK AT AROUND 400 MB ACROSS WEST CENTRAL
PA. THE SNOW OVER CENTRAL PA IS BEING CAUSED BY THE RIGHT ENTRANCE
REGION TO THE JET...WITH OUR LIGHT SNOW BEING CAUSED BY THE LEFT
EXIT REGION. AS THIS JET STREAK SLIDES SOUTHEAST AND WEAKENS
THROUGH 9 PM...EXPECT THE SNOW TO DIMINISH AND MOVE EAST.
NOW TO THE REAL ACTION. AN INTENSE LINE OF SNOW CONTINUES TO MARCH
EAST ACROSS WESTERN NY AND IS JUST ON THE DOORSTEPS OF OUR AREA.
OUR FIRST SPS HAS BEEN ISSUED AND WE WILL LIKELY TO CONTINUE TO
ISSUE SPECIAL WEATHER STATEMENTS THROUGH MIDNIGHT AS THE LINE HEADS
EAST. SNOWFALL AMOUNTS OF AN INCH OR SO ARE POSSIBLE WITH THE
LINE...BUT IT WILL BE THE FACT THAT THE SNOW WILL FALL IN SUCH A
SHORT PERIOD OF TIME THAT IS CAUSE FOR CONCERN. ROUGH TIMING IS
BETWEEN 8 PM AND 10 PM FOR THE WESTERN PART OF THE CWA...ALONG
I-81 IN NY BETWEEN 10 PM AND MIDNIGHT...AND THE SOUTHEASTERN CWA
BETWEEN MIDNIGHT AND 3 AM. THE MODELS DO SHOW THE LINE WEAKENING A
BIT AS IT MARCHES EAST...SO WE MAY SEE THE BIGGEST IMPACT TO OUR
CWA COMING BETWEEN NOW AND MIDNIGHT. THE REST OF THE FORECAST IS
IN GOOD SHAPE REGARDING THE TRANSITION TO LAKE EFFECT SNOW LATER
TONIGHT. THE PREVIOUS AFD IS BELOW...
EVENT #1 IS VISIBLE ON RADAR, WITH BUF SHOWING ENHANCED RETURNS
OVER THE WESTERN EDGE OF LAKE ONTARIO. THIS SHARP COLD FRONT IS
WELL DEPICTED BY THE LATEST RUC13 LOW LEVEL LAPSE RATES, AND WE
ARE USING THIS MESOSCALE MODEL TO FORECAST A POTENTIAL SQUALL
MOVING THROUGH THE FINGER LAKES AND CENTRAL SOUTHERN TIER BY 2-4Z.
BASED ON CURRENT RADAR UPSTREAM AND THE STEEP LAPSE RATES, I CAN
SEE A QUICK INCH OR TWO FROM THIS SQUALL ALONE BEING POSSIBLE. WE
WILL NEED TO CONTINUE TO MONITOR THIS FOR A POTENTIAL SPS TONIGHT.
ONCE THE COLD FRONT MOVES THROUGH, WINDS SHIFT OFF THE LAKE
OVERNIGHT AND BRING A SOLID 2 TO 4 INCHES OF ADDITIONAL SNOW TO
NORTHERN ONEIDA.
NOW BELIEVE THE BAND WILL AFFECT EXTREME NORTHERN ONONDAGA,
NORTHWESTERN MADISON, AND SOUTHWESTERN ONEIDA WITH 1 TO 3 INCHES
OF SNOW. THIS ON TOP OF THE 1 TO 2 INCHES OF SYNOPTIC SNOWFALL
JUSTIFIES AN ADVISORY, THOUGH ONLY A SMALL PORTION OF THE NEW
ADVISORY COUNTIES WILL BE AFFECTED.
A COMBINATION OF SHEAR AND DECREASING LAPSE RATES IN ASSOCIATION
WITH FAST APPROACHING ANTICYCLONE WILL KILL OFF THE LAKE MACHINE
BY MID MORNING. A FEW LIGHT SNOW SHOWERS MAY PERSIST INTO EARLY
AFTERNOON, BUT THE ADVISORY WILL NO LONGER BE NEEDED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
EVENT #2 HAS A STORM SYSTEM SLIDING THROUGH THE MID ATLANTIC
REGION FRIDAY NIGHT INTO SATURDAY. GFS REMAINS THE QUICKEST TO
MOVE SNOW IN FRIDAY EVENING, WITH THE EURO AND NAM A FEW HOURS
SLOWER. HOWEVER THERE IS GOOD AGREEMENT IN STORM TRACK, STRENGTH,
AND QPF.
THE MODELS WERE COLDER THIS MORNING, BUT THE TREND ALL WINTER HAS
BEEN FOR THE MODELS TO BRING THE STORM CENTERS TO THE NORTH IN THE
FINAL RUNS, WITH WARM AIR ENCROACHING FROM THE SOUTH. THERE ARE
SOME HINTS THAT SOME SLEET COULD MIX IN WITH THE SNOW OVER OUR FAR
SOUTHERN FA, BUT RIGHT NOW THE MODEL SOUNDINGS ARE MOST INDICATIVE
OF SNOW.
THE MODEL QPF LOOKS A LITTLE ON THE HIGH SIDE. HOWEVER EVEN WITH A
REDUCTION IN QPF WE ARE VERY CLOSE TO ADVISORY ACCUMS OVER THE
SOUTHERN THIRD OF THE FA.
THE STORM PULLS OUT QUICKEST ON THE GFS, WITH THE EURO AND NAM
AGAIN A FEW HOURS SLOWER. EITHER WAY THE EVENT SHOULD BE DONE BY
LATE AFTERNOON SATURDAY, IF NOT SOONER. WINDS SHIFT AROUND TO A
NORTHEASTERLY DIRECTION, SO IT DOES NOT APPEAR AS THOUGH OUR FA
WILL BE DEALING WITH POST EVENT LAKE SNOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
330 PM UPDATE...
HGTS BLD SUN NGT WITH MID AND LL WAA AHD OF A WRN LAKES LOW. LGT
PCPN SEEM PSBL WITH MUCH UNCERTAINTY ABT THE TEMP PROFILE. MIXED
PCPN SEEMS LIKELY WITH SFC TEMPS NEAR OR BLO FRZG...SO SOME FRZG
RAIN PSBL. LOW MVES SLWLY EAST AS AN OCCLUDED FNT RACES EWRD THRU
THE OH VLY AND WRN NY. TIMING PUSHES THE FNT THRU THE AREA MON
EVE...BUT WITH MODIFIED COLD AIR PUSHING IN FROM THE SW...DO NOT
XPCT A DRAMATIC TEMP DROP LATE MON INTO TUE. UPR LOW LIFTS NORTH
TUE AS THE TROF AXIS PASSES. AIR IS JUST NOT THAT COLD WITH H8
TEMPS FCSTD IN THE -6C TO -8C RANGE. XPCT SOME MOISTURE WITH THE
UPR TROF AND SOME MRGNL LE SNOW SHWRS INTO WED. LATE WED A SFC HI
OVER THE OH VLY BLDS IN BUT WITH ZONAL FLOW OVER THE FCST
AREA...TEMPS RATHER NEUTRAL AND WITH A WEAK SFC TROF AND APRCHG
WC...JUST SOME LGT PCPN IN THE AREA FOR THE END OF THE PD.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
A BRIEF PERIOD OF HIGH PRESSURE WILL BUILD LATER THIS MORNING.
HOWEVER, BEFORE IT DOES, A LAKE EFFECT SNOW BAND WILL MOVE SOUTH
FROM NORTHERN ONEIDA COUNTY AND AFFECT RME AND SYR TAFS SITES. SO
FAR, IT HAS BEEN STUBBORN TO MOVE, SO TIMING HAS BECOME VERY
UNCERTAIN. STILL EXPECTING IT TO MOVE SOUTH BEFORE SUNRISE. AS IT
DOES, IT WILL WEAKEN, THEN DISSIPATE. THIS WILL ALLOW FOR VFR
CONDITIONS FOR MOST OF THE DAY TODAY. ANOTHER LOW PRESSURE SYSTEM
WILL BRING ANOTHER ROUND OF SNOW SHOWERS TONIGHT. THIS LOW,
HOWEVER, IS EXPECTED TO STAY WELL SOUTH OF THE FORECAST AREA. THIS
WILL CAUSE THE HEAVIER SNOW TO BE IN THE AVP AREA. BGM AND ELM
WILL ALSO LIKELY SEE A FEW INCHES OF SNOW TONIGHT. THIS SYSTEM
WILL TAKE MOST OF SATURDAY TO MOVE THROUGH BEFORE HIGH PRESSURE
BUILD AGAIN SATURDAY NIGHT.
WINDS WILL BE OUT OF THE WEST TO NORTHWEST THIS MORNING AROUND
10KTS, WITH SOME LOCATIONS CLOSER TO 15KTS. AS HIGH PRESSURE
BUILDS IN TODAY, THE WINDS WILL TAPER OFF AND, SHOULD GO TO LIGHT
AND VARIABLE TONIGHT.
.OUTLOOK...
FRI NGT...VFR BECOMING IFR AFTER MIDNIGHT WITH WIDESPREAD SNOW
MOVES IN.
SAT...IFR IN SNOW DURING THE MORNING IMPROVING TO VFR DURING THE
AFTN.
SAT NGT AND SUN...MAINLY VFR.
SUN NGT TO MON NGT..MVFR POSSIBLE IN RAIN OR SNOW.
TUE...MVFR IN SNOW SHWRS
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ018-036-037.
WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR NYZ009.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP/HEDEN
SHORT TERM...DJP
LONG TERM...DGM
AVIATION...SLI
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
301 AM MST FRI JAN 20 2012
.DISCUSSION...09Z SURFACE ANALYSIS HAD SHARP ARCTIC BOUNDARY FROM
WEST CENTRAL MT INTO EAST CENTRAL WY INTO SOUTHWEST NE.
TEMPERATURE CONTRAST ACROSS THE FRONT STUNNING...AND VERY SHALLOW
EVIDENCED BY READINGS IN THE LOWER TO MID 30S IN THE BLACK HILLS
AND READINGS AROUND ZERO ON THE ADJACENT PLAINS. WATER VAPOUR
SHOWED SHORTWAVE ENERGY MOVING INTO EASTERN MT WITH ISENTROPIC
LIFT AHEAD OF WAVE PRODUCING A BAND OF -SN FROM CENTRAL MT INTO
EASTERN SD. 00Z NAM/06Z RUC IN GOOD AGREEMENT WITH RADAR
RETURNS/FORECAST...WHICH MEANS -SN WILL END THIS MORNING IN
NORTHWEST SD WITH MINOR ACCUMULATIONS. HIGHS TRICKY TODAY AGAIN
WITH STRONG CONTRAST ACROSS CWA.
TONIGHT...UPPER RIDGE BUILDS TOWARD THE NORTHERN PLAINS WITH
ARCTIC BOUNDARY MORPHING INTO A STRONG WARM FRONT...MAKING IT
THROUGH HALF THE CWA BY MORNING WITH NON-DIURNAL TEMPERATURES
WHERE ARCTIC AIR IS IN PLACE TODAY.
SATURDAY...RIDGE SHIFTS EAST AS UPPER LEVEL TROUGH MOVES INTO THE
ROCKIES. GRADIENT TIGHTENS AS LEE TROUGH/LOW DEVELOPS. 50KT 850MB
WINDS EXPECTED OVER EASTERN PORTIONS OF THE CWA. AMOUNT OF MIXING
BIG QUESTION THOUGH...AS 1KM VISIBLE SATELLITE IMAGERY FROM
THURSDAY SHOWED SNOW COVER OVER THESE AREAS. WILL SPLIT THE
DIFFERENCE AND GO WITH 20-30G40 FOR SOUTHERLY WINDS. WINDS WON/T
BE AS STRONG IN THE WEST. TEMPERATURES WILL BE DRAMATICALLY
WARMER. LIFT AHEAD OF TROUGH MAY PRODUCE SOME -SNRA IN THE FAR
WEST.
SATURDAY NIGHT...MODEST QG-FORCING WILL COMBINE WITH PACIFIC
MOISTURE TO BRING A NICE BAND OF -RASN THROUGH THE CWA. HAVE
INCREASED POPS TO LIKELY. ACCUMULATIONS LOOKED TO BE MINOR GIVEN
RAIN/SNOW MIX.
SUNDAY...COLD FRONT MOVES THROUGH AS SURFACE LOW SHIFTS EAST OF
THE AREA. STRONG GRADIENT EXPECTED WITH GUSTY NORTHWEST WINDS.
TEMPERATURES WILL BE SOMEWHAT COOLER THAN SATURDAY.
EXTENDED...AN UPPER TROUGH WILL CROSS THE WESTERN CONUS
MONDAY...BRINGING CHANCES FOR PRECIP MONDAY NIGHT. NOT MUCH MOISTURE
WILL BE ASSOCIATED WITH THIS SYSTEM...SO QPF IS EXPECTED TO REMAIN
LIGHT. DRIER WEATHER IS EXPECTED TUESDAY AS UPPER RIDGING BUILDS
BEHIND THE DEPARTING TROUGH. A FAST MOVING WAVE IS PROGGED TO CROSS
THE AREA WEDNESDAY BRINGING A RETURN OF LIGHT PRECIP. A SERIES OF
WAVES MAY BRING ADDITIONAL CHANCES FOR LIGHT PRECIP FOR THE SECOND
HALF OF THE WEEK...BUT AT THIS TIME THERE REMAINS MUCH UNCERTAINTY.
TEMPERATURES ARE EXPECTED TO REMAIN NEAR TO SLIGHTLY ABOVE AVERAGE
THROUGH MOST OF THE EXTENDED PERIOD.
&&
.AVIATION...12Z TAFS
LIGHT SNOW WILL CONTINUE THIS MORNING PRIMARILY ACROSS NORTHWEST
INTO CENTRAL SOUTH DAKOTA...RESULTING IN IFR CONDITIONS. CIGS AND
VSBY WILL IMPROVE TO VFR HEADING INTO THE AFTERNOON AS PRECIP SHIFTS
EASTWARD. VFR CONDITIONS ARE THEN EXPECTED TO REMAIN THROUGH FRIDAY
NIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM....CALDERON
AVIATION...CALDERON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 PM CST THU JAN 19 2012
.SHORT TERM...TONIGHT THROUGH TOMORROW
903 PM CST THU JAN 19 2012
MAIN CONCERN CONTINUES TO BE WITH THE SNOW FOR TOMORROW WITH NO
CHANGES PLANNED FOR THE HEADLINES THIS EVENING.
A MID LEVEL SHORTWAVE TROUGH IS MAKING ITS WAY ACROSS ROCKIES WITH
SOME MID TO UPPER LEVEL CLOUD COVER STARTING TO ADVECT INTO THE
REGION ALONG A STRONG UPPER LEVEL JET STREAK OF ABOUT 160KTS AT
250MB BASED ON 20.00Z RAOBS.
AS THIS TROUGH EJECTS OUT OF THE ROCKIES INTO THE PLAINS...SNOW
WILL BEGIN TO FORM OVERNIGHT AND START SPREADING INTO THE
REGION AROUND 3AM OR SO. THE 20.00Z NAM AND 19.21Z SREF HAVE
TRICKLED IN AND ARE STILL PAINTING A SIMILAR PICTURE TO THEIR
PREVIOUS RUNS. THE 19.21Z SREF IS SHOWING SOME HIGHER
PROBABILITIES OF 4 INCHES OR MORE IN A 12 HOUR PERIOD ALONG THE
AXIS OF WHERE THE CURRENT ADVISORY IS LAID OUT WITH 0 PERCENT
PROBABILITIES OF 8 INCHES OR MORE. THE NAM CONTINUES TO BE THE
WORRISOME MODEL WITH HIGHER SNOWFALL TOTALS ALONG A NARROW BAND
ACROSS NORTHEAST IOWA WHERE THE QPF AMOUNTS CAME UP A BIT WITH THE
20.00Z RUN. THE OTHER ISSUE IS WITH THE 750MB WARM LAYER AND HOW
WARM IT WILL BE TOMORROW WHICH WILL DIRECTLY AFFECT HOW DEEP THE
DENDRITIC GROWTH ZONE IS. THE NAM HAS TRENDED TO BE WARMER IN THIS
LAYER WHILE THE GFS HAS BEEN COOLER WITH MUCH OF THE THERMAL
PROFILE FROM THE SURFACE UP TO 550MB IN THE DGZ. THE 19.22Z TO
20.01Z RUC FORECAST SOUNDINGS HAVE NOT HELPED MUCH TO THIS POINT
IN DETERMINING WHICH WAY TO TREND AS EARLIER THEY HAD GONE WITH A
COOLER WARM LAYER...BUT THE LATEST COUPLE OF RUNS HAVE GONE TOWARD
THE NAM THINKING SO PERHAPS THAT IS THE WAY TO TREND.
LONG STORY SHORT...HAVE COLLABORATED WITH NEIGHBORING OFFICES AND
HAVE DECIDED TO HOLD OFF ON ANY UPGRADES OR EXPANSIONS OF THE
CURRENT HEADLINED AREA. THE MAIN CONCERNS WERE WHETHER TO UPGRADE
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN TO A WINTER STORM
WARNING FOR SOME POSSIBLE BANDING AND HIGHER SNOWFALL
TOTALS IN THE 6 TO 8 INCH RANGE...ALONG WITH PUSHING THE ADVISORY
NORTH A TIER OF COUNTIES FROM WABASHA COUNTY TO JACKSON COUNTY.
WITH MUCH OF THE OTHER 20.00Z GUIDANCE NOT IN YET...HAVE DECIDED
THAT IT WOULD BE MORE PRUDENT TO LET THE MIDNIGHT CREW GET SOME
MORE INFORMATION TO TAKE A BETTER SHOT AT HOW THE SYSTEM LOOKS AS
IT GETS OUT OF THE ROCKIES.
PLEASE SEE THE PREVIOUS AFD FOR COMMENTS ON THE WEATHER BEYOND
TOMORROW.
20.00Z NAM AND 19.21Z SREF GUIDANCE HAS STARTED TRICKLING
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
320 PM CST THU JAN 19 2012
UPPER TROUGH OVER THE PLAINS LOOKS TO LIFT NORTHEAST THROUGH THE
AREA SUNDAY NIGHT AND AWAY FROM THE AREA ON MONDAY. CERTAINLY THIS
BEARS WATCHING FOR TIMING GIVEN THE TREND FOR THIS TROUGH TO BE
AMPLIFIED AND SLOWER. IN FACT THE NEW 19.12Z ECMWF SLOWED DOWN THE
TROUGH A BIT MORE. SHOULD SEE ANY RAIN/FREEZING RAIN CHANGE OVER TO
SNOW THROUGH THE NIGHT SUNDAY NIGHT...WITH ALL SNOW MONDAY...THOUGH
AGAIN THE PRECIPITATION SHOULD BE WINDING DOWN MONDAY. MAY HAVE TO
WATCH FOR POTENTIAL ADVISORY SNOW SUNDAY NIGHT...AND POSSIBLY INTO
MONDAY IF THE NEW ECMWF IS CORRECT.
REST OF NEXT WEEK CONTINUES TO SHOW A SOMEWHAT ACTIVE PATTERN...WITH
MODELS IN VERY GOOD AGREEMENT SHOWING SHORTWAVE TROUGHS MOVING
THROUGH TUESDAY NIGHT INTO WEDNESDAY...AS WELL AS ON THURSDAY.
HOWEVER...NONE OF THESE TROUGHS LOOK TO HAVE A LOT OF MOISTURE WITH
THEM...LIKELY SHUNTED OFF BY THE DEEPER SUNDAY NIGHT/MONDAY TROUGH.
FOLLOWED A CONSENSUS APPROACH GIVEN THE GOOD AGREEMENT...RESULTING
IN MOSTLY 20-40 PERCENT CHANCES FOR THESE TROUGHS. TEMPERATURES WILL
BE WARMER NEXT WEEK THAN THIS WEEK...THANKS TO THE MAIN POLAR
WESTERLIES SHIFTING WELL NORTH INTO CANADA. IT DOES NOT APPEAR THAT
ENOUGH WARM AIR ENTERS ANY OF THE TROUGHS TO RESULT IN LIQUID
PRECIPITATION...THOUGH.
&&
.AVIATION...THROUGH 06Z SATURDAY
1130 PM CST THU JAN 19 2012
CONTINUED FOCUS IS FOR THE SNOW ON FRIDAY...MAINLY WHEN IT WILL
START AND STOP ALONG WITH WHEN THE HEAVIEST SNOW WILL FALL. 20.00Z
UPPER AIR SOUNDINGS FROM MPX AND DVN SHOW A FAIRLY DRY LOW LEVEL
LAYER FROM THE SURFACE ON UP TO 800MB THAT WILL HAVE TO BE WORKED
ON BEFORE THE SNOW CAN REACH THE GROUND. THE LATEST TREND IN THE
SHORT TERM GUIDANCE IS TO PUSH THE START TIME BACK A FEW HOURS DUE
TO THE LOW LEVEL DRY LAYER THAT THE SNOW WILL HAVE TO WORK ON
INITIALLY. OTHERWISE...SNOWFALL RATES WILL LIKELY BE THE STRONGEST
FROM LATE MORNING INTO THE EARLY AFTERNOON WITH VISIBILITY
DROPPING TO 1/4SM TO 1/2SM OVER THIS PERIOD. THIS SNOW SHOULD COME
TO AN END LATE IN THE AFTERNOON AT RST AND EARLY IN THE EVENING AT
LSE...BUT SOME MVFR TO IFR CEILINGS MAY HANG ON THROUGH THE
NIGHT...SO HAVE PLAYED IT A BIT PESSIMISTIC ON CIGS GOING TO 6Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
320 PM CST THU JAN 19 2012
WI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR
WIZ041>044-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
MNZ086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST FRIDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
430 AM MST FRI JAN 20 2012
.DISCUSSION...
220 AM MST FRI JAN 20 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS CONTINUES TO SHOW LONG
FETCH OF W/NW FLOW ACROSS THE CENTRAL US WITH TROUGH OVER THE
NORTHEAST. AT THE SURFACE A STRONG COLD FRONT CONTINUES TO LINGER
ALONG THE COLORADO/KANSAS STATE LINE WITH A 15-20F SPREAD IN TEMPS
FROM THE EAST TO THE WEST ACROSS THE CWA.
TODAY-SATURDAY...MAIN FOCUS DURING THESE PERIODS CONTINUES TO BE ON
TEMPS ACROSS THE CWA...COMPLICATED BY LINGERING FRONT. THE FRONT IS
EXPECTED TO BEGIN TO LIFT EAST THIS MORNING. WESTERLY FLOW AT THE
SURFACE SHOULD BRING MILD TEMPS INTO THE WESTERN HALF OF THE
CWA...WITH COLD TEMPS LINGER ALL DAY ACROSS THE EASTERN PART OF
THE CWA. A WEAK SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS
LATER TODAY WILL PUSH A REINFORCING SHOT OF COLD AIR SOUTH
TOWARDS THE CWA...RESULTING IN THE COLD FRONT SWINGING BACK
TOWARDS THE W/SW THIS AFTERNOON/EVENING. HIGH TEMPS TODAY MAY BE
REACHED BEFORE NOON OVER CENTRAL PARTS OF THE CWA...WITH A NON-
DIURNAL COOLING TREND POSSIBLE THIS AFTERNOON OVER PARTS OF THE
CWA. CURRENTLY EXPECTING ABOUT A 30F SPREAD IN HIGH TEMPS FROM THE
EAST TO THE WEST...WITH HIGHS NEAR 60F IN EASTERN COLORADO...AND
IN THE UPPER 20S NEAR NORTON. S/SW FLOW DEVELOPS SATURDAY...WHICH
WILL HELP SOUR OUT THE COLDEST AIR FROM MOST OF THE CWA...THOUGH
EASTERN LOCATIONS WILL STILL LIKELY REMAIN BELOW NORMAL.
SUNDAY...A TROUGH DEVELOPING OVER GREAT BASIN WILL PUSH
EAST...WITH THE MEAN TROUGH AXIS OVER WESTERN KANSAS BY 18Z
SUNDAY. LARGE SCALE ASCENT COMBINED WITH INCREASING MOISTURE AHEAD
OF TROUGH AXIS WILL WILL OVERSPREAD CWA SUNDAY MORNING...QUICKLY
PUSHING E/NE OF THE CWA DURING THE AFTERNOON. ECMWF CONTINUES TO
BE THE WETTEST SOLUTION...THOUGH GFS AT LEAST SHOWS SOME SUPPORT
FOR PRECIP IN THE NE CWA. MAIN CHANGE TO PREVIOUS FORECAST WAS TO
BUMP UP POPS UP IN THE N/NE...AND SPEED UP THE EXIT OF PRECIP
DURING THE AFTERNOON FROM THE WEST TO THE EAST. VERY DRY AIR WILL
ADVECT INTO THE CWA FROM THE WEST DURING THE AFTERNOON...WITH
WINDY CONDITIONS DEVELOPING BY MIDDAY. WE MAY NEED TO ISSUE A RED
FLAG WARNING FOR WESTERN PARTS OF THE CWA AND A WIND ADVISORY FOR
THE MAJORITY OF THE CWA...HOWEVER ITS STILL TOO EARLY FOR THIS
FORECAST CYCLE.
DR
FOR THE PERIOD MONDAY THROUGH THURSDAY...A COLD FRONT WILL MOVE
THROUGH THE REGION ON TUESDAY WITH BREEZY NORTHWEST WINDS AND COLDER
TEMPERATURES. MODELS SHOW SOME LIGHT PRECIPITATION WITH THE FRONT
WHICH MAY END UP NOTHING MORE THAN FLURRIES. TEMPERATURES REBOUND
QUICKLY WITH ABOVE NORMAL TEMPERATURES WEDNESDAY AND THURSDAY.
024
&&
.AVIATION...
430 AM MST FRI JAN 20 2012
FOR THE 12Z TAFS...VFR THROUGH THE PERIOD. A COLD FRONT WILL MOVE
ACROSS THE REGION LATER THIS MORNING WHICH WILL CAUSE WINDS TO VEER
FROM THE SOUTHEAST TO THE NORTHWEST WITH TIME AND BECOME GUSTY.
GUSTS WILL DIMINISH CLOSE TO 00Z. MID/HIGH CLOUDS WILL CONTINUE TO
OVERSPREAD THE REGION WITH BASES 10K-15K FEET.
024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
646 AM EST FRI JAN 20 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(330 AM EST FRI JAN 20 2012)
AN UPPER LEVEL DISTURBANCE WILL BRING ANOTHER ROUND OF SNOW TO THE
AREA TODAY INTO TONIGHT...AFFECTING THE FRIDAY EVENING COMMUTE.
COLD AIR WILL EXIT THE AREA SATURDAY AND THEN THE FOLLOWING WORK
WEEK WILL SEE ABOVE NORMAL TEMPERATURES WITH RAIN EXPECTED SUNDAY
NIGHT INTO MONDAY AND AGAIN IN THE MIDDLE OF THE WEEK.
&&
.SHORT TERM...(330 AM EST FRI JAN 20 2012)
(TODAY THROUGH SATURDAY)
NO SIGNIFICANT CHANGES WERE MADE TO THE INHERITED FORECAST. THE
WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR SOUTHERN HALF OF THE
FORECAST AREA FOR 3 TO 5 INCHES OF SNOW TODAY AND TONIGHT.
ADVISORY HEADLINES STILL LOOK ON TRACK. ALTHOUGH MOST OF THE SNOW
SHOULD FALL AROUND THE GENERAL TIME OF THE AFTERNOON COMMUTE...
MODEST SNOWFALL RATES AROUND HALF AN INCH PER HOUR WILL MINIMIZE
IMPACTS. THE GENERAL SETUP /A SHALLOW DGZ WAY UP ABOVE 10KFT/
CERTAINLY DOES NOT FAVOR HEAVY SNOWFALL. GIVEN A DEEP SATURATED
LAYER BENEATH THE DGZ ALONG WITH DEEP UPWARD VERTICAL MOTION...SNOW
RATIOS SHOULD BE QUITE LOW /10-15:1/...WHICH IS SUPPORTED BY THE
SNOW TOOL. THE RELATIVELY DENSE FLAKES COMBINED WITH LIGHT WINDS
SHOULD PREVENT SIGNIFICANT VISIBILITY RESTRICTIONS FROM BEING AN
ISSUE. SNOW IS EXPECTED TO END FRIDAY NIGHT SHORTLY AFTER MIDNIGHT.
SNOW TOTALS STILL LOOK TO BE 4-5 INCHES ALONG AND SOUTH OF I-96...
WITH GENERALLY 2-4 INCHES BETWEEN US-10 AND I-96.
&&
.LONG TERM...(400 AM EST FRI JAN 20 2012)
(SUNDAY THROUGH THURSDAY)
THERE ARE TWO STORM EVENTS TO WATCH THIS COMING WEEK. THE
FIRST IS THE SYSTEM SUNDAY NIGHT INTO TUESDAY MORNING. THEN
THERE IS THE POTENTIAL FOR ANOTHER SIGNIFICANT STORM IN THE
WEDNESDAY TO THURSDAY TIME FRAME.
ZONAL FLOW RETURNS THIS COMING WEEK...DISPLACING THE ARCTIC AIR. A
RETROGRADING UPPER LOW OVER CENTRAL CANADA DUMPS MOST OF ITS ENERGY
INTO A DEVELOPING SYSTEM OVER THE GULF OF ALASKA BY MONDAY. THAT
RESULTS IN A MORE ZONAL FLOW OVER THE CONUS UNTIL THE PACIFIC LONG
WAVE TROUGH MOVES EAST INTO THE CENTRAL UNITED STATES (BEYOND OUR
FORECAST RANGE).
THAT IN TURN LOCKS THE ARCTIC AIR WELL NORTH IN CENTRAL CANADA AND
ALASKA MOST OF THIS COMING WEEK AND WILL BRING ABOVE NORMAL
TEMPERATURES. WITH THIS PATTERN WE WILL SEE FREQUENT PERIODS OF
PRECIPITATION AS THE STORM TRACK WILL REMAIN NEAR MICHIGAN.
AS FOR THE SUNDAY NIGHT AND MONDAY STORM...CONTINUITY IS BEST WITH
THE ECMWF THE FOUR MOST RECENT RUNS OF THE ECMWF SHOW A VERY SIMILAR
SOLUTION... WHICH IS A MUCH MORE WRAPPED UP SYSTEM THAT TAKES UNTIL
TUESDAY MORNING TO CLEAR THE AREA. IT IS ALSO SLOWER TO BRING THE
PRECIPITATION INTO THE AREA SUNDAY. I FAVORED THE ECMWF SO I PUSHED
THE POPS TOWARD A SLOWER SOLUTION OF THE ECMWF. THIS WOULD BRING A
SIGNIFICANT AMOUNT OF RAIN TO THE AREA AS THE SURFACE LOW TRACKS
WELL WEST OF SOUTHWEST LOWER MICHIGAN. THERE WOULD BE AROUND A HALF
INCH OF RAIN WITH THIS SYSTEM NO MATTER WHICH MODEL IS CORRECT.
HOWEVER WITH THE ECMWF BEING SLOWER TO START THE PRECIPITATION AND A
TOUCH WETTER WE COULD SEE A HALF TO ONE INCH OF QPF. THE PCPN THAT
FALLS MON AFTERNOON INTO MONDAY NIGHT WOULD BE RAIN TO SNOW ON
EITHER MODEL. THE ECMWF WOULD PRODUCE MEASURABLE SNOW MONDAY NIGHT
ACROSS THE CWA.
THE NEXT SYSTEM IN THE WED/THURSDAY TIME FRAME IS A PHASING ISSUE
WITH THE NORTHERN AND SOUTHERN STREAM. THE LATEST VERSION OF THE GFS
PHASES THE NORTHERN AND SOUTHERN STREAM WAVES WHILE ECMWF DOES NOT.
NEITHER MODEL HAS A DECENT CONTINUITY WITH THIS SYSTEM SO WE WILL
STICK WITH LOW POPS FOR NOW AND SEE HOW THIS PLAYS OUT.
NO MATTER WHAT HAPPENS TEMPERATURES WILL RUN WELL ABOVE NORMAL ALL
WEEK.
&&
.AVIATION...(645 AM EST FRI JAN 20 2012)
THE LOW CLOUDS (MVFR CIGS FROM LAKE EFFECT CLOUDS) HAVE DRIFTED TO
THE I-69 AREA AS OF 1130Z. THESE WILL COVER THE CWA BY 13Z ONLY TO
DISSIPATE BY LATE MORNING LAKE CLOUD LEVEL WINDS BECOME MORE SOUTH
SOUTHEAST (NOT OFF LAKE MICHIGAN). I EXPECT ALL TAF SITES (JXN
SHOULD BE IN THE CLOUDS SOON) WILL BE MVFR FOR SEVERAL HOURS THIS
MORNING.
THE SNOW AREA WILL MOVE INTO SOUTHWEST LOWER MICHIGAN BY MID
AFTERNOON. MY TIMING WAS BASED ON THE HRRR TIMING AND SOME
CONSIDERATION WAS GIVEN TO THE 09Z RUN ISENTROPIC LIFT NEAR 700 MB.
THIS SEEMS TO MATCH THE PROGRESSION OF THE SNOW ACROSS IOWA EARLY
THIS MORNING NICELY. THE HEAVIEST SNOW WILL BE BETWEEN 5 PM AND 9 PM
THIS EVENING. JXN SHOULD BE THE LAST SITE TO LOSS THE SNOW. ONCE THE
SNOW ENDS... MVFR CIGS SHOULD PERSIST INTO SATURDAY MORNING.
&&
.MARINE...(330 AM EST FRI JAN 20 2012)
WILL BE ENDING THE SMALL CRAFT ADVISORY WITH THIS FORECAST PACKAGE
AS WINDS AND WAVES SHOULD CONTINUE TO RAPIDLY SUBSIDE. NO HEADLINES
ARE EXPECTED UNTIL POSSIBLY SATURDAY NIGHT NORTH OF MUSKEGON WHEN
SOUTHEAST WINDS WILL STRENGTHEN CONSIDERABLY IN ADVANCE OF THE NEXT
APPROACHING LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...(330 AM EST FRI JAN 20 2012)
SOME FLUCTUATIONS DUE TO ICE EFFECTS ARE POSSIBLE THROUGH SATURDAY.
A RAPID WARM UP BEGINNING SUNDAY ACCOMPANIED WITH RAIN SUNDAY NIGHT
COULD SEND RIVER LEVELS BACK UP EARLY NEXT WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WX ADVISORY ALONG AND SOUTH OF INTERSTATE 96 TODAY
AND TONIGHT.
LM...NONE.
&&
$$
SYNOPSIS: TJT
SHORT TERM: TJT
LONG TERM: WDM
AVIATION: WDM
MARINE: TJT
HYDROLOGY: TJT
AREA FORECAST DISCUSSION
NWS NORMAN OK
528 AM CST FRI JAN 20 2012
.AVIATION...
LOW CLOUDS...WITH CEILING AROUND 400 FT...HAVE MOVED INTO
FAR SOUTHEAST OKLAHOMA THIS MORNING. EXTRAPOLATION MOVES
LOW CLOUDS INTO/NEAR OUN/OKC AROUND 14Z. WILL ADD A MENTION
OF IFR CEILINGS AT OUN/OKC AROUND 800 FEET FOR A FEW HOURS
AFTER 14Z BUT OVERALL CONFIDENCE THAT THIS WILL OCCUR IS NOT
HIGH. FLOW SHOULD LIMIT LOW CLOUD COVER TO EASTERN OKLAHOMA
BY MID TO LATE MORNING. A COLD FRONT AND NORTH WINDS WILL GRADUALLY
MOVE SOUTH TODAY BRINGING NORTH WINDS TO ALL TAF SITES BY 22Z.
&&
.PREV DISCUSSION... /ISSUED 416 AM CST FRI JAN 20 2012/
DISCUSSION...
SKIES ARE GENERALLY CLEAR ACROSS THE FA EARLY THIS MORNING...HOWEVER
LOW CLOUDS AND AREAS OF FOG ARE CLOSE TO FAR SOUTHEAST OKLAHOMA.
THE LATEST RUC SLOWLY ADVECTS HIGHER DEWPOINT AIR INTO BRYAN AND
ATOKA COUNTIES SHORTLY AFTER SUNRISE WHICH MAY RESULT IN SOME FOG
AND OR/VERY LOW CEILINGS. FARTHER NORTH...SEVERAL MODELS INCREASE
9H HUMIDITY INTO CENTRAL AND NORTH CENTRAL OKLAHOMA DURING THE
EARLY TO MID MORNING HOURS. JUST ENOUGH UPGLIDE MAY BE PRESENT FOR
LOW CLOUDS TO FORM MAINLY EAST OF I-35. FLOW SHOULD VEER ENOUGH
AHEAD OF ANOTHER FRONT TO CLEAR CLOUDS (IF ANY) BY LATE MORNING.
HAVE FOLLOWED 6Z NAM12 FOR GUIDANCE ON DAYTIME HIGHS TODAY...WHICH
IS COLDER ACROSS THE NORTH THAN THE 00Z RUN. STILL SHOULD SEE VERY
WARM TEMPS ACROSS SOUTHERN THIRD OF THE AREA...ESPECIALLY TEXAS
COUNTIES. THIS WILL RESULT IN A HIGHER RISK OF WILDFIRES AS
HUMIDITY LEVELS DROP BELOW 20% FOR AWHILE DURING THE AFTERNOON. NORTH
WINDS AND MORE HUMID AIR SHOULD REACH SOUTHWEST OK/WESTERN N
TEXAS BY LATE AFTERNOON HOWEVER.
THE COLD FRONT TODAY SHOULD BE THE LAST ONE THAT WILL TAP INTO MUCH
COLDER AIR ACROSS SOUTHERN CANADA AND THE NORTHERN PLAINS.
SATURDAY WILL BE CHILLY MOST AREAS BUT SOUTH WINDS WILL RETURN
MOST AREAS DURING THE AFTERNOON. WIND SPEEDS WILL INCREASE
OVERNIGHT WHICH WILL HOLD TEMPERATURES UP...AS A STRONG TROUGH
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. THE EC MODEL IS A
LITTLE SLOWER WITH THE MOVEMENT OF THIS TROUGH WHICH WILL BRING
RATHER GUSTY NORTHWEST WINDS AND MUCH DRIER AIR. ALTHOUGH THE
FORCING WILL BRING RATHER STRONG...LITTLE IF ANY PRECIPITATION IS
EXPECTED. THE MAIN CONCERN WITH THIS SYSTEM WILL BE AN INCREASE
RISK OF WILDFIRES WITH GUSTY WINDS AND RELATIVELY LOW HUMIDITY
(ESPECIALLY WEST).
WIND SPEEDS SHOULD DIMINISH QUICKLY SUNDAY NIGHT AS THE UPPER SYSTEM
MOVES EAST AND SURFACE GRADIENT DECREASES.
WILL KEEP THE CHANCES FOR RAIN NEXT WEEK HIGHEST ON TUESDAY. STILL SOME
UNCERTAINTIES WITH THIS SYSTEM. EC HAS MUCH STRONGER FLOW ON WESTERN
SIDE OF TROUGH AND EVENTUALLY DEVELOPS A CLOSED LOW OVER
SOUTHWEST TEXAS BY WEDNESDAY. GFS MORE PROGRESSIVE AND BALANCED AND
MOVES THIS TROUGH EAST BY MID TO LATE WEDNESDAY. THE GFS SEEMS
MORE REALISTIC BUT SEVERAL ENSEMBLE MEMBERS ARE CLOSE TO 00Z EC
RUN. EVEN IF EC IS CLOSER...MAIN IMPACT WOULD ALSO BE TUESDAY
INTO EARLY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 52 22 44 37 / 0 0 0 10
HOBART OK 61 22 45 37 / 0 0 0 0
WICHITA FALLS TX 68 27 50 38 / 0 0 0 0
GAGE OK 49 18 45 39 / 0 0 0 0
PONCA CITY OK 47 17 40 35 / 0 10 0 10
DURANT OK 69 33 51 43 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
416 AM CST FRI JAN 20 2012
.DISCUSSION...
SKIES ARE GENERALLY CLEAR ACROSS THE FA EARLY THIS MORNING...HOWEVER
LOW CLOUDS AND AREAS OF FOG ARE CLOSE TO FAR SOUTHEAST OKLAHOMA.
THE LATEST RUC SLOWLY ADVECTS HIGHER DEWPOINT AIR INTO BRYAN AND
ATOKA COUNTIES SHORTLY AFTER SUNRISE WHICH MAY RESULT IN SOME FOG
AND OR/VERY LOW CEILINGS. FARTHER NORTH...SEVERAL MODELS INCREASE
9H HUMIDITY INTO CENTRAL AND NORTH CENTRAL OKLAHOMA DURING THE
EARLY TO MID MORNING HOURS. JUST ENOUGH UPGLIDE MAY BE PRESENT FOR
LOW CLOUDS TO FORM MAINLY EAST OF I-35. FLOW SHOULD VEER ENOUGH
AHEAD OF ANOTHER FRONT TO CLEAR CLOUDS (IF ANY) BY LATE MORNING.
HAVE FOLLOWED 6Z NAM12 FOR GUIDANCE ON DAYTIME HIGHS TODAY...WHICH
IS COLDER ACROSS THE NORTH THAN THE 00Z RUN. STILL SHOULD SEE VERY
WARM TEMPS ACROSS SOUTHERN THIRD OF THE AREA...ESPECIALLY TEXAS
COUNTIES. THIS WILL RESULT IN A HIGHER RISK OF WILDFIRES AS
HUMIDITY LEVELS DROP BELOW 20% FOR AWHILE DURING THE AFTERNOON. NORTH
WINDS AND MORE HUMID AIR SHOULD REACH SOUTHWEST OK/WESTERN N
TEXAS BY LATE AFTERNOON HOWEVER.
THE COLD FRONT TODAY SHOULD BE THE LAST ONE THAT WILL TAP INTO MUCH
COLDER AIR ACROSS SOUTHERN CANADA AND THE NORTHERN PLAINS.
SATURDAY WILL BE CHILLY MOST AREAS BUT SOUTH WINDS WILL RETURN
MOST AREAS DURING THE AFTERNOON. WIND SPEEDS WILL INCREASE
OVERNIGHT WHICH WILL HOLD TEMPERATURES UP...AS A STRONG TROUGH
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. THE EC MODEL IS A
LITTLE SLOWER WITH THE MOVEMENT OF THIS TROUGH WHICH WILL BRING
RATHER GUSTY NORTHWEST WINDS AND MUCH DRIER AIR. ALTHOUGH THE
FORCING WILL BRING RATHER STRONG...LITTLE IF ANY PRECIPITATION IS
EXPECTED. THE MAIN CONCERN WITH THIS SYSTEM WILL BE AN INCREASE
RISK OF WILDFIRES WITH GUSTY WINDS AND RELATIVELY LOW HUMIDITY
(ESPECIALLY WEST).
WIND SPEEDS SHOULD DIMINISH QUICKLY SUNDAY NIGHT AS THE UPPER SYSTEM
MOVES EAST AND SURFACE GRADIENT DECREASES.
WILL KEEP THE CHANCES FOR RAIN NEXT WEEK HIGHEST ON TUESDAY. STILL SOME
UNCERTAINTIES WITH THIS SYSTEM. EC HAS MUCH STRONGER FLOW ON WESTERN
SIDE OF TROUGH AND EVENTUALLY DEVELOPS A CLOSED LOW OVER
SOUTHWEST TEXAS BY WEDNESDAY. GFS MORE PROGRESSIVE AND BALANCED AND
MOVES THIS TROUGH EAST BY MID TO LATE WEDNESDAY. THE GFS SEEMS
MORE REALISTIC BUT SEVERAL ENSEMBLE MEMBERS ARE CLOSE TO 00Z EC
RUN. EVEN IF EC IS CLOSER...MAIN IMPACT WOULD ALSO BE TUESDAY
INTO EARLY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 52 22 44 37 / 0 0 0 10
HOBART OK 61 22 45 37 / 0 0 0 0
WICHITA FALLS TX 68 27 50 38 / 0 0 0 0
GAGE OK 49 18 45 39 / 0 0 0 0
PONCA CITY OK 47 17 40 35 / 0 10 0 10
DURANT OK 69 33 51 43 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1243 PM EST FRI JAN 20 2012
.UPDATE...
REGIONAL RADAR MOSAIC CONTINUES TO SHOW INTENSIFYING BAND OF SNOW
FROM EAST CENTRAL IOWA INTO NORTH CENTRAL ILLINOIS. THIS ZONE OF
STRONGER ISENTROPIC ASCENT WILL OVERSPREAD NORTHERN HALF OF AREA
LATER THIS AFTERNOON INTO TONIGHT. A FEW REPORTS OF 5 TO 6 INCHES
OF SNOW ACCUMULATION ALREADY HAVE BEEN REPORTED ACROSS NORTHWEST
IOWA. STILL SOME CONCERN FOR SOME AREAS RECEIVING WARNING CRITERIA
ACCUMULATIONS BY LATE EVENING. NAM/GFS ISENTROPIC PROGS CONTINUE
TO INDICATE SOME SLIGHT WEAKENING OF ISENTROPIC UPGLIDE AS
STRONGEST FORCING FROM EASTERN IOWA/NORTHERN ILLINOIS TRACKS INTO
NORTHERN INDIANA AS NORTHERN VORT MAX ACROSS IOWA/SOUTHERN
MINNESOTA TENDS TO GET MORE SHEARED ACROSS THE SOUTHERN GREAT
LAKES REGION. WILL CONTINUE TO ASSESS 12Z DATA AND OBSERVATIONAL
TRENDS BUT AT THIS TIME WILL MAINTAIN A HIGHER END WINTER WEATHER
ADVISORY FOR SNOW ACCUMULATIONS OF 4 TO 7 INCHES. PERIOD OF MOST
INTENSE SNOWFALL RATES STILL APPEARS TO BE IN THE 21Z-03Z
TIMEFRAME WHEN ISENTROPIC LIFT IS MAXIMIZED ALONG WITH AN
INCREASINGLY FAVORABLE COLOCATION OF DENDRITIC GROWTH ZONE AND
UPWARD MOTION. ONLY OTHER TWEAK TO FORECAST WAS TO CONTINUE TREND
OF INCREASING SNOWFALL AMOUNTS ACROSS SOUTHERN HALF OF CWA. SOME
INDICATIONS IN HRRR OUTPUT OF SECONDARY BANDED AREA OF SNOW DEVELOPING
LATER THIS EVENING ACROSS LOCATIONS FURTHER SOUTH AS LOW LEVEL
FRONTOGENESIS BEGINS TO INCREASE IN RESPONSE TO SECONDARY UPPER
LEVEL WAVE PROGRESSING THROUGH THE CENTRAL PLAINS THIS AFTERNOON.
&&
.AVIATION...
18Z TAFS...DETERIORATING CONDITIONS FOR AVIATION WEATHER THROUGH
THE REMAINDER OF THE AFTERNOON. LOW LEVELS WILL CONTINUE TO
SATURATE OVER THE NEXT FEW HOURS AS AN AREA OF STRONG WARM
ADVECTION SHIFTS EASTWARD FROM THE WESTERN GREAT LAKES REGION.
STRONGEST FORCING STILL APPEARS TO BE IN THE 22Z-03Z TIMEFRAME
WHEN THE HEAVIEST SNOWFALL RATES ARE EXPECTED ALONG WITH PERIODS
OF LIFR CONDITIONS IN HEAVIER SNOWFALL. SYSTEM SHOULD BEGIN TO
EXIT TO THE EAST AFTER 06Z...ALTHOUGH SNOW MAY LINGER INTO MUCH OF
THE OVERNIGHT AT KFWA AS A SECONDARY UPPER LEVEL SHORT WAVE LIFTS
NORTHEAST FROM THE CENTRAL PLAINS. TREND TO VFR CONDITIONS IS THEN
EXPECTED FOR SATURDAY MORNING AS THE SYSTEM EXITS THE AREA. EAST
SOUTHEAST WINDS THIS AFTERNOON WILL BACK MORE NORTHERLY TOWARD THE
END OF THE PERIOD AS THE SFC LOW ASSOCIATED WITH THIS SYSTEM TRACK
SOUTH OF THE AREA.
&&
PREV DISCUSSION... /ISSUED 422 AM EST FRI JAN 20 2012/
SHORT TERM.../TODAY THROUGH SATURDAY NIGHT/
SHRTWV MOVG ACROSS THE ROCKIES THIS MORNING RESULTING IN AN AREA
OF SNOW OVER SD/MN/IA. THIS SYSTEM WILL MOVE RAPIDLY EAST TODAY
AND TONIGHT CAUSING SNOW TO OVERSPREAD OUR AREA. STRONG H85
THETA-E ADVECTION AND DECENT UPR LEVEL DIVERGENCE IN RIGHT
ENTRANCE REGION OF JET AHEAD OF THE SHRTWV ALONG WITH MODEST
H85-H7 FRONTOGENESIS APPEAR TO BE MAIN FORCING MECHANISMS FOR
PRECIP SPREADING INTO OUR AREA. MODELS SIMILAR IN MOVG A MODERATE
AREA OF SNOW ACROSS THE AREA TODAY. GFS/SREF ARE A BIT FASTER TO
MOVE THE PRECIP INTO THE CWA... AND APPEAR TO BE HANDLING THE
EASTWARD PROGRESSION BETTER THAN THE NAM. THUS, CONTD WITH LIKELY
POPS BY MIDDAY ACROSS NW 1/3 OF CWA WITH SNOW EXPECTED TO
OVERSPREAD THE ENTIRE AREA THIS AFTN. EMPIRICAL SNOWFALL FCSTG
METHODS AND MODEL QPF CONT TO SUGGEST 5-7 INCHES IN 12-18HRS
ACROSS NRN PORTION OF THE CWA. MODELS HAVE ALSO TRENDED FARTHER
SOUTH WITH SGFNT QPF SUGGESTING 2-4 INCHES OF ACCUMS ACROSS SRN
PORTION OF CWA AS WELL SO EXPANDED EARLIER ISSUED WINTER WX
ADVISORY ACROSS REMAINDER OF THE CWA. TEMPS OFF TO A COLD START
THIS MORNING...GENERALLY IN THE SINGLE DIGITS AND DESPITE FAIRLY
STRONG H85 WAA DVLPG TODAY WILL STRUGGLE TO REACH THE L20S AS
DVLPG SFC EASTERLY FLOW...CLOUD COVER AND PRECIP HINDER RISES. WK
CAA BEHIND THE SHRTWV OVERNIGHT ALONG WITH LINGERING CLOUD COVER
SHOULD ONLY ALLOW TEMPS TO FALL 5-10F FROM AFTN HIGHS. SFC HIGH
PRESSURE WILL MOVE ACROSS THE GRTLKS SATURDAY/SATURDAY NIGHT
PROVIDING FAIR WX. WAA WILL GRADUALLY STRENGTHEN DURING THIS
PERIOD BUT WITH FRESH SNOW COVER IN PLACE EXPECT TEMPS WILL REMAIN
RATHER COLD WITH HIGHS IN THE M20S AND LOWS IN THE TEENS.
LONG TERM... / SUNDAY THROUGH THURSDAY /
PROGRESSIVE FLOW PATTERN FROM EAST ASIA TO NOAM WILL ALLOW PACIFIC
AIR TO FLOOD INTO MUCH OF THE LOWER 48 THIS PERIOD AS POLAR VORTEX
RE-FOCUSES INTO THE GULF OF ALASKA. THIS WILL SUPPORT TEMPS
GENERALLY ABOVE NORMAL AND SEVERAL CHANCES FOR PCPN SUNDAY INTO NEXT
WEEK. OPTED TO TAILOR GRIDS/FCST TOWARDS THE MORE CONSISTENT 12/00Z
ECMWF DAYS 3/4 AND CLOSER TO A MODEL CONSENSUS THEREAFTER.
A POTENT SHORTWAVE TROUGH WILL LIKELY EJECT INTO THE CENTRAL PLAINS
ON SUNDAY AND THEN TAKE ON A NEGATIVE TILT AS IT PIVOTS INTO THE MID
MS VALLEY AND GREAT LAKES BY SUNDAY NIGHT/MONDAY. MID LVL HEIGHT
FALLS WITH THIS FEATURE WILL INDUCE SFC CYCLOGENESIS WITH A
DEEPENING CYCLONE PROGGED TO TRACK WEST OF THE FA TOWARDS THE
WESTERN GREAT LAKES DURING THIS TIME...WITH A DEVELOPING 50-60 KT
LLJ SUPPORTING SIGNIFICANT LOW LVL MOISTURE/THETA-E ADVECTION NWD
INTO THE AREA. GEM/ECMWF PROGS BRING SFC DEWPOINTS INTO THE MID 40S
TO LOW 50S TOWARDS DAYBREAK MONDAY. THIS LOOKS TO BE CONCURRENT WITH
THE ARRIVAL OF STEEP MID LVL LAPSE RATES WHICH SUPPORTS THE
INHERITED SLIGHT CHC FOR THUNDER AND HVY RAIN LATER SUNDAY NIGHT
INTO MONDAY MORNING. ISSUED A ESF TO COVER HYDRO CONCERNS GIVEN SNOW
MELT...RECENT HEAVY RAINFALL IN THE SOUTH/EAST...AND THE POTENTIAL
FOR LOCALIZED HEAVIER RAIN. OTHERWISE...EXPECT MAINLY DRY CONDITIONS
DURING THE DAY ON SUNDAY WITH A COMBINATION OF MELTING
SNOW...MOISTURE ADVECTION...AND THE RESULTING INVERSION SUPPORTING
INCREASING/LOWERING STRATUS AND THE POTENTIAL FOR SOME
DRIZZLE/FOG/LIGHT SHOWERS BY LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING BEFORE STRONGER FORCING ARRIVES.
LOW LEVEL CAA IN THE WAKE OF THE SYSTEM CDFNT MONDAY MORNING SHOULD
ALLOW FOR FALLING TEMPS MONDAY AFTERNOON...WITH SCT RAIN SHOWERS
CHANGING TO SNOW SHOWERS BY MONDAY AFTN/EVE AS WRAP AROUND MOISTURE
PIVOTS THROUGH. ONLY MINOR ACCUMS EXPECTED...MAINLY NW. DRY WITH
NEAR NORMAL TEMPS TUESDAY AS SHORTWAVE TROUGH LIFTS OUT. A MODEL
CONSENSUS KEEPS THE NEXT UPPER TROUGH IN PROGRESSIVE FLOW FRACTURED
AND UNPHASED RESULTING IN A WEAKER SYSTEM AND ONLY LOWER CHC POPS
FOR SOME LIGHT RAIN OR SNOW BY WEDNESDAY/THURSDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ SATURDAY FOR
INZ003>009-012>018-020-022>027-032>034.
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ077>081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR OHZ001-002-
004-005-015-016-024-025.
LM...NONE.
&&
$$
SHORT TERM...JT
LONG TERM...STEINWEDEL
AVIATION...MARSILI
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1045 AM MST FRI JAN 20 2012
.DISCUSSION...
220 AM MST FRI JAN 20 2012
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS CONTINUES TO SHOW LONG
FETCH OF W/NW FLOW ACROSS THE CENTRAL US WITH TROUGH OVER THE
NORTHEAST. AT THE SURFACE A STRONG COLD FRONT CONTINUES TO LINGER
ALONG THE COLORADO/KANSAS STATE LINE WITH A 15-20F SPREAD IN TEMPS
FROM THE EAST TO THE WEST ACROSS THE CWA.
TODAY-SATURDAY...MAIN FOCUS DURING THESE PERIODS CONTINUES TO BE ON
TEMPS ACROSS THE CWA...COMPLICATED BY LINGERING FRONT. THE FRONT IS
EXPECTED TO BEGIN TO LIFT EAST THIS MORNING. WESTERLY FLOW AT THE
SURFACE SHOULD BRING MILD TEMPS INTO THE WESTERN HALF OF THE
CWA...WITH COLD TEMPS LINGER ALL DAY ACROSS THE EASTERN PART OF
THE CWA. A WEAK SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS
LATER TODAY WILL PUSH A REINFORCING SHOT OF COLD AIR SOUTH
TOWARDS THE CWA...RESULTING IN THE COLD FRONT SWINGING BACK
TOWARDS THE W/SW THIS AFTERNOON/EVENING. HIGH TEMPS TODAY MAY BE
REACHED BEFORE NOON OVER CENTRAL PARTS OF THE CWA...WITH A NON-
DIURNAL COOLING TREND POSSIBLE THIS AFTERNOON OVER PARTS OF THE
CWA. CURRENTLY EXPECTING ABOUT A 30F SPREAD IN HIGH TEMPS FROM THE
EAST TO THE WEST...WITH HIGHS NEAR 60F IN EASTERN COLORADO...AND
IN THE UPPER 20S NEAR NORTON. S/SW FLOW DEVELOPS SATURDAY...WHICH
WILL HELP SOUR OUT THE COLDEST AIR FROM MOST OF THE CWA...THOUGH
EASTERN LOCATIONS WILL STILL LIKELY REMAIN BELOW NORMAL.
SUNDAY...A TROUGH DEVELOPING OVER GREAT BASIN WILL PUSH
EAST...WITH THE MEAN TROUGH AXIS OVER WESTERN KANSAS BY 18Z
SUNDAY. LARGE SCALE ASCENT COMBINED WITH INCREASING MOISTURE AHEAD
OF TROUGH AXIS WILL WILL OVERSPREAD CWA SUNDAY MORNING...QUICKLY
PUSHING E/NE OF THE CWA DURING THE AFTERNOON. ECMWF CONTINUES TO
BE THE WETTEST SOLUTION...THOUGH GFS AT LEAST SHOWS SOME SUPPORT
FOR PRECIP IN THE NE CWA. MAIN CHANGE TO PREVIOUS FORECAST WAS TO
BUMP UP POPS UP IN THE N/NE...AND SPEED UP THE EXIT OF PRECIP
DURING THE AFTERNOON FROM THE WEST TO THE EAST. VERY DRY AIR WILL
ADVECT INTO THE CWA FROM THE WEST DURING THE AFTERNOON...WITH
WINDY CONDITIONS DEVELOPING BY MIDDAY. WE MAY NEED TO ISSUE A RED
FLAG WARNING FOR WESTERN PARTS OF THE CWA AND A WIND ADVISORY FOR
THE MAJORITY OF THE CWA...HOWEVER ITS STILL TOO EARLY FOR THIS
FORECAST CYCLE.
DR
FOR THE PERIOD MONDAY THROUGH THURSDAY...A COLD FRONT WILL MOVE
THROUGH THE REGION ON TUESDAY WITH BREEZY NORTHWEST WINDS AND COLDER
TEMPERATURES. MODELS SHOW SOME LIGHT PRECIPITATION WITH THE FRONT
WHICH MAY END UP NOTHING MORE THAN FLURRIES. TEMPERATURES REBOUND
QUICKLY WITH ABOVE NORMAL TEMPERATURES WEDNESDAY AND THURSDAY.
024
&&
.AVIATION...
1006 AM MST FRI JAN 20 2012
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE
PREVAILING PERIOD. MODEL SOUNDING ANALYSIS INDICATES SURFACE
SATURATION AFTER 03Z THIS EVENING...INDICATING A CHANCE FOR FOG
DEVELOPMENT. WILL LET NEXT SHIFT EVALUATE. OTHERWISE...GUSTY
NORTHWEST WINDS WILL BECOME CALM OVERNIGHT AS PRESSURE GRADIENT
RELAXES AND SURFACE HIGH MOVES EASTWARD. GUSTY WINDS WILL RETURN
BY MID MORNING AS PRESSURE GRADIENT TIGHTENS ACROSS THE HIGH
PLAINS.
PMM
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
520 PM EST FRI JAN 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL CREST OVER THE REGION TONIGHT AS LOW PRESSURE
APPROACHES NEW ENGLAND FROM THE SOUTHWEST. LOW PRESSURE WILL PASS
OUT TO SEA WELL SOUTH OF NEW ENGLAND ON SATURDAY. HIGH PRESSURE
WILL BUILD IN FROM THE NORTHWEST SATURDAY NIGHT AND WILL GRADUALLY
SHIFT INTO THE MARITIMES ON SUNDAY. A WARM FRONT WILL LIFT INTO
SOUTHERN NEW ENGLAND ON MONDAY AND WILL BE QUICKLY FOLLOWED BY A
COLD FRONT MONDAY NIGHT. A TRAILING TROUGH OF LOW PRESSURE WILL
SLOWLY MOVE THROUGH NEW ENGLAND ON TUESDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY..CRESTING OVER
THE AREA ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
VERY LITTLE CHANGE TO THE CURRENT PACKAGE. WITH LOW TDS AND A VERY
DRY SOUNDING...TEMPS WILL TAKE A NOSEDIVE LATER THIS EVENING AS
THE GRADIENT COLLAPSES.
LATEST 3 KM HRRR BRINGS SNOW TO THE FAR WESTERN REACHES OF NH BY
07Z...REACHING MAINE BY AROUND 09Z WHICH APPEARS TOO FAST
CONSIDERING OUR DRY/ARCTIC AIR IN PLACE.
PREV DISC...
CLEAR AND VERY COLD FIRST HALF OF THE NIGHT AS HIGH PRESSURE
CRESTS OVER THE REGION...BUT CLOUDS WILL QUICKLY PUSH BACK INTO
THE REGION AS LOW PRESSURE APPROACHES NEW ENGLAND FROM THE
SOUTHWEST. CLOUDS WILL GRADUALLY LOWER AND THICKEN FROM WEST TO
EAST AND SOME LIGHT SNOW OR SNOW SHOWERS WILL EDGE INTO THE
CONNECTICUT VALLEY AND SOUTHERN NEW HAMPSHIRE TOWARD DAYBREAK. NOT
LOOKING FOR MUCH IN THE WAY OF ACCUMULATION THROUGH 12Z WITH JUST
A DUSTING LIKELY IN FAR SOUTHWEST ZONES. EXPECTING LOWS 5 TO 15
BELOW IN THE NORTH AND 5 BELOW TO 5 ABOVE IN THE SOUTH.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
LIGHT SNOW WILL PERSIST IN SOUTHERN ZONES MAINLY DURING THE MORNING
HOURS BEFORE TAPERING OFF IN THE AFTERNOON. MODELS NOT PUTTING
OUT MUCH IN THE WAY OF QPF WITH MOST AREAS SEEING A TENTH OF AN INCH
OR LESS BUT A DECENT FLUFF FACTOR MAY PRODUCE UP TO TWO INCHES OF
SNOW IN FAR SOUTHERN NEW HAMPSHIRE. LOOKING FOR AROUND AN INCH OR
LESS ACROSS THE REMAINDER OF THE FORECAST AREA. EXPECT PARTIAL
CLEARING FROM NORTHWEST TO SOUTHEAST LATER IN THE AFTERNOON AS
LOW PRESSURE HEADS OUT TO SEA SOUTH OF NEW ENGLAND. HIGH
TEMPERATURES WON`T GET PAST THE TEENS IN THE NORTH AND MID TEENS
TO LOWER 20S IN THE SOUTH.
COLD HIGH PRESSURE WILL BUILD SOUTHEAST FROM CANADA SATURDAY NIGHT
CLEARING SKIES AND ALLOWING TEMPERATURES TO PLUMMET ONCE AGAIN.
LOOKING FOR LOWS 5 TO 15 BELOW IN THE NORTH AND 5 BELOW TO 10
ABOVE IN THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGH PRES BRINGS FAIR WX SUNDAY. LOW PRES AND A TRAILING CD FRONT
APPROACH FROM THE W SUNDAY NGT AS A WRM FNT EXTENDING E FROM THE
LOW HAS ANOTHER WEAKER LOW FORM ALONG THE COAST. AS THIS SYSTEM
MOVES TOWARD NEW ENGLAND THE COASTAL LOW WILL COMBINE WITH THE
HIGH TO THE NE TO HELP KEEP COLDER AIR IN OVER THE FCST AREA
ESPECIALLY WHEN THE COASTAL FNT FORMS.
GRADUALLY THOUGH THE WRM AIR STREAMING NE IN AN INCREASINGLY
STRONGER S SW FLOW ALOFT EVENTUALLY ERODES THE CD AIR FORCING SN
TO CHANGE TO MIX THEN TO RA FROM SW TO NE ACROSS THE FCST AREA. SN
AMOUNTS MAY BE LIMITED TO MORE NRN AND NE AREAS AND AMOUNTS, IF
ANY, WOULD LIKELY BE MINIMAL. ICING FROM SLEET AND FREEZING RA MAY
BE MORE OF AN ISSUE DEPENDING ON HOW LONG THE CD AIR HOLDS IN AT
LOW LEVELS AND AT THE SFC.
MODELS VARY ON QPF AMOUNTS BUT AN INCH OF QPF THRU THE EVENT
APPEARS VERY PSBL WITH A MAJORITY OF IT LIKELY FALLING AS RA. THE
GFS IS SHOWING EVEN HIGHER QPF WHILE NAM AND ECMWF SHOW
CONSIDERABLY LESS..AT LEAST THRU 00Z TUESDAY.
THE CD FNT SWEEPS THRU MONDAY NGT WITH PRCP ENDING OR AT LEAST
TAPERING OFF FROM SW TO NE. ON TUESDAY COLDER AIR FILTERS IN AND
AN UPR LEVEL TROF ALONG WITH UPSLOPE LOW LVL FLOW WILL HELP
PRODUCE -SHSN ACTIVITY..ESPECIALLY ACROSS THE N/MT ZONES.
HIGH PRES BRINGS FAIR WX WEDNESDAY. A WEAK UPR LVL SHORT WAVE
TROF MOVING THRU IN AN UPR LVL NW FLOW MAY BRING THE CHC OF SOME
-SHSN ON THURSDAY...MAINLY ACROSS MORE NRN AND NE AREAS. HIGH PRES
TRIES TO BUILD IN BRIEFLY FOR FRIDAY.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
THRU SUNDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TONIGHT WITH SOME AREAS OF MVFR CEILINGS/VSBY
DEVELOPING OVER SOUTHERN NEW HAMPSHIRE TOWARD MORNING. MVFR/IFR
CEILINGS AND VSBY MAINLY IN SOUTHERN AREAS ON SATURDAY...IMPROVING
IN THE AFTERNOON. VFR SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...IFR OR LIFR IN MIXED PRCP
DEVELOPING SUNDAY NGT...CONTINUING THRU MONDAY AND ENDING MONDAY
NGT AS IT TRANSITIONS OVER TO RA.
&&
.MARINE...
SHORT TERM...SCA IN EFFECT THROUGH EARLY EVENING. SCA`S WILL LIKELY
BE NEEDED LATE SATURDAY AFTERNOON THROUGH MIDNIGHT SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...WINDS AND SEAS INCREASE ON
MONDAY...REACHING SCA LEVELS WITH WINDS POSSIBLY REACHING GALE
FORCE...AHEAD OF LOW PRES AND A TRAILING CD FNT. CONDITIONS
BRIEFLY LET UP LATE MONDAY NGT AS THE CD FNT MOVES THRU...ONLY TO
INCREASE TO SCA OR GALE FORCE TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
343 PM CST FRI JAN 20 2012
.DISCUSSION...
/336 PM CST FRI JAN 20 2012/
A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE/RAIN WAS ISSUED
EARLIER THIS AFTN BASED ON MODEL DEPICTIONS OF WEAK LIFT OCCURRING
WITHIN AN INCREASINGLY SATURATED ATMOSPHERE /SFC TO ABOUT 10KFT/.
REGIONAL OBSERVATIONS FROM ASOS/AWOS...INCREASING SATURATION
INFERRED FROM VAD WIND PROFILES...AND SATELLITE IMAGERY ALL SUPPORT
THE IDEA THAT THE LOWER ATMOSPHERE IS BECOMING SATURATED WITH
TIME. WITH A MODIFIED ARCTIC AIR MASS IN PLACE...SFC TEMPERATURES
HAVE BEEN BELOW FREEZING FOR LONG ENOUGH THAT ANY LIQUID PCPN
SHOULD FREEZE ON CONTACT WITH ELEVATED AND UNTREATED SURFACES. IN
OTHER WORDS...A LIGHT GLAZE IS EXPECTED TO FORM ON UNTREATED AND
ELEVATED SURFACES AND AFFECT THE EVENING RUSH HOUR COMMUTE. PCPN
SHOULD END BY MIDNIGHT AS FORCING MOVES EAST OF THE AREA.
SFC HIGH BUILDS ACROSS THE REGION LATER TONIGHT AND PERSISTS THROUGH
TOMORROW NIGHT AS THE UPPER LEVEL FLOW BECOMES INCREASINGLY
DIFFLUENT AHEAD OF THE NEXT SHORTWAVE. LATEST MODEL RUNS ARE NEARLY
UNANIMOUS IN DEPICTING A STRONG TROF BECOMING NEGATIVELY TILTED AS
IT LIFTS THROUGH THE REGION ON SUNDAY AFTN AND EVENING ALTHOUGH
THERE IS SOME MODEL DISAGREEMENT ABOUT WHERE THE SRN SFC LOW WILL
DVLP /GEM DEPICTS SFC CYCLOGENESIS IN NEBRASKA WHILE THE GFS PUTS IT
IN OKLAHOMA/. REGARDLESS...SFC LOW WILL LIFT A WARM FRONT THROUGH
THE CWA ON SUNDAY CAUSING TEMPERATURES TO WARM NEARLY 15 DEGREES
ABOVE AVERAGE FOR THIS TIME OF YEAR. DIFFLUENT FLOW ALOFT AND A LLJ
RIDING OVER THE LIFTING WMFNT MAY PRODUCE SOME SPOTTY TO SCT RAIN
SHOWERS ON SUNDAY MORNING HOWEVER THE MAIN PCPN EVENT WILL PROBABLY
OCCUR ON SUNDAY AFTERNOON AND EVENING. FACTORS SUPPORTING
THUNDERSTORMS OVER PART OF THE AREA ON SUNDAY NIGHT INCLUDE
INCREASING LAPSE RATES...PW VALUES AROUND 0.7 IN...DECREASED
STABILITY FROM THE COLD AIR ALOFT WITHIN A NEGATIVELY TILTED
TROF...AND FAVORABLE PLACEMENT BENEATH THE LEFT EXIT REGIONS OF
CYCLONICALLY CURVED JET STREAKS AT H5 AND H3. PCPN SHOULD END AFTER
THE COLD FRONT MOVES THROUGH WITH PERHAPS SOME CLOUDS PERSISTING DUE
TO CYCLONIC FLOW ALOFT.
AFTER A BRIEF PD OF RIDGING ON MON NIGHT AND TUE...MODELS SHOW
ANOTHER SYSTEM CUTTING OFF OVER NRN MEXICO OR SWRN TEXAS ON TUE
NIGHT. LOW CONFIDENCE ATTM IN THE FORECAST FOR THE MIDDLE AND END OF
NEXT WEEK GIVEN MODEL VARIABILITY WITH THIS SYSTEM OVER THE PAST
COUPLE OF DAYS.
KANOFSKY/BRITT
&&
.AVIATION...
/1101 AM CST FRI JAN 20 2012/
LOCAL WRF AND RUC MODEL RUNS THIS MORNING ARE TRENDING THE
FORECAST TOWARD A MORE ICY LATE AFTERNOON/EVENING SOLUTION FOR
LOCATIONS ALONG AND SOUTH OF I-44 CORRIDOR IN MISSOURI AND I-70 IN
ILLINOIS. ATMOSPHERE WILL CONTINUE TO SATURATE THIS AFTERNOON WITH
PERSISTENT LOW LEVEL MOISTURE CONVERGENCE. RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET WILL PROVIDE ADDITIONAL LIFT LATE THIS
AFTERNOON TO PRODUCE A BAND OF FREEZING DRIZZLE OR LIGHT FREEZING
RAIN FROM THE OZARKS NORTHEAST TOWARD THE ST. LOUIS METRO AREA.
THIS BAND WILL EXPAND WITH TIME THIS EVENING TO THE EAST ACROSS
SOUTHERN ILLINOIS BEFORE EXITING THE CWA AROUND 06Z. ICE
ACCUMULATION SHOULD REMAIN BELOW ONE TENTH OF AN INCH.
OTHERWISE...EAST WIND WILL BECOME NORTH THROUGH THE PERIOD. SHOULD
SEE IMPROVING CONDITIONS AFTER MIDNIGHT WITH SKIES SCT OUT.
SPECIFICS FOR KSTL...
FREEZING DRIZZLE OR LIGHT FREEZING RAIN WILL DEVELOP THIS
AFTERNOON AND IMPACT THE TERMINAL THIS EVENING BETWEEN 23Z AND
02Z. CEILING WILL FALL TO LOW END MVFR WITH LOCAL REDUCTIONS IN
VISIBILITY THIS EVENING. EAST WIND WILL BECOME NORTH THROUGH THE
PERIOD. ICE ACCUMULATION SHOULD REMAIN LESS THAN A TENTH OF AN
INCH...BUT AMBIENT TEMPERATURES IN THE 20S WILL CAUSE UNTREATED
RUNWAYS TO BECOME VERY SLICK.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CRAWFORD
MO-FRANKLIN MO-IRON MO-JEFFERSON MO-MADISON MO-REYNOLDS MO-
ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS
MO-STE. GENEVIEVE MO-WASHINGTON MO.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BOND IL-
CLINTON IL-FAYETTE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL-ST. CLAIR IL-
WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1137 AM CST FRI JAN 20 2012
.UPDATE...
/1137 AM CST FRI JAN 20 2012/
...WINTER WEATHER ADVISORY ISSUED FOR LIGHT ACCUMULATION OF ICE...
HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE SOUTHEASTERN HALF OF
THE CWA FOR LATE THIS AFTERNOON AND THIS EVENING. RUC...NAM AND
LOCAL WRF SOUNDINGS ARE ALL INDICATING THE LOW CLOUDS OVER THE
AREA SHOULD THICKEN THROUGH THE AFTERNOON...WITH THE RUC SOUNDING
SHOWING SATURATION BETWEEN THE SURFACE TO 10K FT AT FAM BY 3 PM
AND STL BY 5 PM. THIS STRONGLY SUGGESTS THE POTENTIAL FOR AT LEAST
DRIZZLE FORMATION. MODELS ARE ALSO SHOWING THAT THERE WILL BE
INCREASED ASCENT OVER THE AREA DURING THIS SAME TIME FRAME CAUSED
BY SHORTWAVE MOVING QUICKLY EASTWARD FROM THE CENTRAL PLAINS.
MODEL QPF FIELDS ALSO ARE SHOWING AROUND A TENTH OF AN INCH OF QPF
OVER THE SOUTHERN CWA. EASTERLY WINDS AND LOW CLOUDS WILL LIMIT
TEMPERATURE RISES...SO EXPECT PRECIPITATION TO FALL AS MAINLY
FREEZING DRIZZLE OR LIGHT FREEZING RAIN. TEMPERATURES OVER THE FAR
SOUTHERN PART OF THE CWA MAY ALLOW FOR A BRIEF CHANGEOVER TO
LIQUID. OTHERWISE...HAVE LEFT ONLY CHANCES FOR SNOW OVER THE THE
NORTHERN CWA AS MAIN SNOW BAND IS STAYING WELL NORTH OF THE AREA.
BRITT
&&
.DISCUSSION...
/340 AM CST FRI JAN 20 2012/
DEALING WITH A NORTHERN STREAM AND SOUTHERN STREAM SYSTEM...THAT
WILL TRY TO CONVERGE OVER THE FORECAST AREA LATER TODAY.
STARTING OFF RATHER COLD THIS MORNING WITH TEMPS IN THE SINGLE
DIGITS FAR NORTH TO THE MID 20S FAR SOUTH. IN THE MEANTIME...SC DECK
ADVECTING NORTHWARD INTO SOUTHEAST MISSOURI AND SOUTHERN
ILLINOIS...AND COULD REACH METRO AREA BY MID MORNING. THEN IN THE
NORTH...MID CLOUD DECK WITH NORTHERN STREAM SYSTEM HAS BEGUN TO MOVE
IN. THIS COULD STIFLE TEMPS TODAY. SO BACKED OFF ON HIGH TEMPS...
RANGING FROM THE MID 20S FAR NORTH TO THE MID 30S SOUTH...THOUGH
COULD SEE UPPER 30S OVER CENTRAL MO...SINCE THEY WILL SEE A BIT MORE
SUN TODAY.
AS FOR PCPN CHANCES...SOME LIGHT SNOW WILL BE POSSIBLE OVER
NORTHEAST MO...WEST CENTRAL ILLINOIS THIS MORNING AS FIRST IN A
SERIES OF SHORTWAVES MOVES THROUGH. SOME CONCERN ABOUT FREEZING
DRIZZLE OVER SOUTHERN MISSOURI THIS MORNING AS SC DECK SLIDES IN.
CONDENSATION PRESSURE DEFICITS ARE FAIRLY HIGH...BUT DO BEGIN TO
LOWER TOWARDS MIDDAY...WITH SOME WEAK WAA WHICH COULD HELP TO
PRODUCE SOME FREEZING DRIZZLE/DRIZZLE. FOR NOW KEPT THAT AREA DRY
TIL THIS AFTERNOON. AS FOR THIS AFTERNOON...START TO SEE SYSTEMS
CONVERGE OVER REGION...WITH AREAS ALONG I-70 POSSIBLY IN THE DRY
SLOT BETWEEN THE TWO SYSTEMS. KEPT MENTION OF PATCHY FREEZING
DRIZZLE/DRIZZLE ALONG I-70 CORRIDOR...MAINLY FOR AREAS EAST OF A
MEXICO TO MONTGOMERY CITY TO OWENSVILLE LINE. THIS INCLUDES THE ST.
LOUIS METRO AREA. OTHERWISE...REST OF AREA TO SEE ONLY LIGHT QPF AS
WELL...BUT ENOUGH TO KEEP LOW CHANCE POPS GOING...AND DID RAISE THEM
A BIT OVER SOUTHEAST MO AND SOUTHERN IL. COULD SEE UP TO A TENTH OF
AN INCH OF LIGHT SNOW OVER NORTHEAST MO/WEST CENTRAL IL THIS
AFTERNOON. AS FOR ANY ICE ACCUMULATION...CAN JUST EXPECT A VERY
LIGHT GLAZE AT THIS TIME.
BYRD
THINGS WILL REACH A CRESCENDO EARLY THIS EVENING AS ALL OF THE
ELEMENTS...AS BEST THEY CAN...TRY TO COME TOGETHER OVER THE FA. NAM
IS A BIT SLOWER AND AN OUTLIER WITH THE FORWARD SPEED WHICH IS HARD
TO UNDERSTAND GIVEN SUCH A ZONAL MID LEVEL FLOW...AND PREFER A RAPID
TRANSIT THRU THE FA THIS EVENING OF THE LIFT AND MOISTURE. DEEPER
MOISTURE...THAT WILL BE ABLE TO RESULT IN ICE PRODUCTION...WILL
REMAIN LARGELY TO OUR N...LEAVING BEHIND A MOSTLY DRIZZLE SETUP OVER
THE FA THAT WILL BE DRIVEN PRIMARILY BY A WEAK INVERTED TROF
TRAVELLING THRU THE CNTRL/SRN FA...BEFORE A MORE CONGEALED SFC LO
CAN FORM TO OUR E. SFC TEMPS OVER MUCH OF THE AREA ARE EXPECTED TO
BE AT OR BELOW 32F FROM THE START OF TONIGHT...AND THIS WILL
ULTIMATELY RESULT IN FREEZING DRIZZLE. THANKS TO THE RAPID SPEED OF
ANY SOURCES OF LIFT...AMOUNTS WILL STRUGGLE TO MEASURE AND HAVE GONE
WITH POPS AT OR BELOW 50PCT FOR THE REGION. BY 9PM...PCPN IS
EXPECTED TO LEAVE OR COME TO AN END OVER THE STL METRO AREA AND
AREAS TO THE NW...WHILE THE PCPN SHOULD END BY MIDNIGHT FOR AREAS TO
THE SE. NAM SUGGESTS THAT PCPN MAY BE MORE SUBSTANTIAL AND HANG ON
LONGER DUE TO THE SLOWER EWD MOVEMENT OF THE DEVELOPING SFC LO...
WHICH WILL LINGER LO LEVEL CONVERGENCE FOR LONGER WHICH WILL DRIVE
THE FZDZ. THIS SOLUTION OVERALL REJECTED FOR ITS SLOWER MOVEMENT...
BUT CONSIDERING HOW THE SYSTEM WAS STILL JUST COMING ONSHORE AT 00Z
THIS EVENING...IF THIS PLAYS OUT...IT WILL RESULT IN MORE
SUBSTANTIAL ICE ACCRETION.
PREFERRED WARMER MOS TEMPS ON SATURDAY AS DECENT AMOUNT OF SUNSHINE
EXPECTED. STRENGTHENING S FLOW ON SUNDAY WILL ALLOW TEMPS TO SURGE
WELL ABOVE AVERAGE THANKS TO RISING TEMPS THE NIGHT BEFORE.
QUESTIONABLE AMOUNTS OF STRATUS WITH INCREASED MOISTURE MAY RESULT
IN LOWER MET MOS NUMBERS PANNING OUT. CDFNT WILL THEN COME THRU
LATE IN THE DAY...AND SIMILAR TO WHAT WE ARE GOING TO SEE TODAY...
EVERYTHING COMES TOGETHER BRIEFLY FOR A SHORT-LIVED PCPN EVENT LATE
IN THE DAY...BUT WITH MUCH WARMER TEMPS...THIS WILL BE RAIN. ECMWF
EVEN GOES SO FAR TO SUGGEST THUNDER POTENTIAL.
AFTER ANOTHER QUIET PERIOD EARLY NEXT WEEK...ECMWF AND GFS DIVERGE
SIGNIFICANTLY ON WHAT TO DO WITH THE NEXT BIG WRN CONUS SYSTEM.
ECMWF CUTS IT OFF INTO NRN OLD MEXICO...WHILE GFS KEEPS IT AS A
STRONG PROGRESSIVE WAVE THAT WILL PUSH THRU THE FA DURING
WEDNESDAY-THURSDAY. WHILE ECMWF EVEN PUSHES THRU A GREATLY REDUCED
NRN STREAM SYSTEM AT THIS TIME...NEEDLESS TO SAY...LO CONFIDENCE
CONTINUES FOR THE MEDIUM RANGE. MAINTAINED LO CHC POPS FROM
PREVIOUS FCST. TEMPS SHOULD BE NOT TOO FAR AWAY FROM AVERAGE.
TES
&&
.AVIATION...
/1101 AM CST FRI JAN 20 2012/
LOCAL WRF AND RUC MODEL RUNS THIS MORNING ARE TRENDING THE
FORECAST TOWARD A MORE ICY LATE AFTERNOON/EVENING SOLUTION FOR
LOCATIONS ALONG AND SOUTH OF I-44 CORRIDOR IN MISSOURI AND I-70 IN
ILLINOIS. ATMOSPHERE WILL CONTINUE TO SATURATE THIS AFTERNOON WITH
PERSISTENT LOW LEVEL MOISTURE CONVERGENCE. RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET WILL PROVIDE ADDITIONAL LIFT LATE THIS
AFTERNOON TO PRODUCE A BAND OF FREEZING DRIZZLE OR LIGHT FREEZING
RAIN FROM THE OZARKS NORTHEAST TOWARD THE ST. LOUIS METRO AREA.
THIS BAND WILL EXPAND WITH TIME THIS EVENING TO THE EAST ACROSS
SOUTHERN ILLINOIS BEFORE EXITING THE CWA AROUND 06Z. ICE
ACCUMULATION SHOULD REMAIN BELOW ONE TENTH OF AN INCH.
OTHERWISE...EAST WIND WILL BECOME NORTH THROUGH THE PERIOD. SHOULD
SEE IMPROVING CONDIITONS AFTER MIDNIGHT WITH SKIES SCT OUT.
SPECIFICS FOR KSTL...
FREEZING DRIZZLE OR LIGHT FREEZING RAIN WILL DEVELOP THIS
AFTERNOON AND IMPACT THE TERMINAL THIS EVENING BETWEEN 23Z AND
02Z. CEILING WILL FALL TO LOW END MVFR WITH LOCAL REDUCTIONS IN
VISIBILITY THIS EVENING. EAST WIND WILL BECOME NORTH THROUGH THE
PERIOD. ICE ACCUMULATION SHOULD REMAIN LESS THAN A TENTH OF AN
INCH...BUT AMBIENT TEMPERATURES IN THE 20S WILL CAUSE UNTREATED
RUNWAYS TO BECOME VERY SLICK.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR CRAWFORD MO-FRANKLIN MO-IRON MO-JEFFERSON MO-
MADISON MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST.
LOUIS CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WASHINGTON MO.
IL...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR BOND IL-CLINTON IL-FAYETTE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1118 AM CST FRI JAN 20 2012
.DISCUSSION...
/340 AM CST FRI JAN 20 2012/
DEALING WITH A NORTHERN STREAM AND SOUTHERN STREAM SYSTEM...THAT
WILL TRY TO CONVERGE OVER THE FORECAST AREA LATER TODAY.
STARTING OFF RATHER COLD THIS MORNING WITH TEMPS IN THE SINGLE
DIGITS FAR NORTH TO THE MID 20S FAR SOUTH. IN THE MEANTIME...SC DECK
ADVECTING NORTHWARD INTO SOUTHEAST MISSOURI AND SOUTHERN
ILLINOIS...AND COULD REACH METRO AREA BY MID MORNING. THEN IN THE
NORTH...MID CLOUD DECK WITH NORTHERN STREAM SYSTEM HAS BEGUN TO MOVE
IN. THIS COULD STIFLE TEMPS TODAY. SO BACKED OFF ON HIGH TEMPS...
RANGING FROM THE MID 20S FAR NORTH TO THE MID 30S SOUTH...THOUGH
COULD SEE UPPER 30S OVER CENTRAL MO...SINCE THEY WILL SEE A BIT MORE
SUN TODAY.
AS FOR PCPN CHANCES...SOME LIGHT SNOW WILL BE POSSIBLE OVER
NORTHEAST MO...WEST CENTRAL ILLINOIS THIS MORNING AS FIRST IN A
SERIES OF SHORTWAVES MOVES THROUGH. SOME CONCERN ABOUT FREEZING
DRIZZLE OVER SOUTHERN MISSOURI THIS MORNING AS SC DECK SLIDES IN.
CONDENSATION PRESSURE DEFICITS ARE FAIRLY HIGH...BUT DO BEGIN TO
LOWER TOWARDS MIDDAY...WITH SOME WEAK WAA WHICH COULD HELP TO
PRODUCE SOME FREEZING DRIZZLE/DRIZZLE. FOR NOW KEPT THAT AREA DRY
TIL THIS AFTERNOON. AS FOR THIS AFTERNOON...START TO SEE SYSTEMS
CONVERGE OVER REGION...WITH AREAS ALONG I-70 POSSIBLY IN THE DRY
SLOT BETWEEN THE TWO SYSTEMS. KEPT MENTION OF PATCHY FREEZING
DRIZZLE/DRIZZLE ALONG I-70 CORRIDOR...MAINLY FOR AREAS EAST OF A
MEXICO TO MONTGOMERY CITY TO OWENSVILLE LINE. THIS INCLUDES THE ST.
LOUIS METRO AREA. OTHERWISE...REST OF AREA TO SEE ONLY LIGHT QPF AS
WELL...BUT ENOUGH TO KEEP LOW CHANCE POPS GOING...AND DID RAISE THEM
A BIT OVER SOUTHEAST MO AND SOUTHERN IL. COULD SEE UP TO A TENTH OF
AN INCH OF LIGHT SNOW OVER NORTHEAST MO/WEST CENTRAL IL THIS
AFTERNOON. AS FOR ANY ICE ACCUMULATION...CAN JUST EXPECT A VERY
LIGHT GLAZE AT THIS TIME.
BYRD
THINGS WILL REACH A CRESCENDO EARLY THIS EVENING AS ALL OF THE
ELEMENTS...AS BEST THEY CAN...TRY TO COME TOGETHER OVER THE FA. NAM
IS A BIT SLOWER AND AN OUTLIER WITH THE FORWARD SPEED WHICH IS HARD
TO UNDERSTAND GIVEN SUCH A ZONAL MID LEVEL FLOW...AND PREFER A RAPID
TRANSIT THRU THE FA THIS EVENING OF THE LIFT AND MOISTURE. DEEPER
MOISTURE...THAT WILL BE ABLE TO RESULT IN ICE PRODUCTION...WILL
REMAIN LARGELY TO OUR N...LEAVING BEHIND A MOSTLY DRIZZLE SETUP OVER
THE FA THAT WILL BE DRIVEN PRIMARILY BY A WEAK INVERTED TROF
TRAVELLING THRU THE CNTRL/SRN FA...BEFORE A MORE CONGEALED SFC LO
CAN FORM TO OUR E. SFC TEMPS OVER MUCH OF THE AREA ARE EXPECTED TO
BE AT OR BELOW 32F FROM THE START OF TONIGHT...AND THIS WILL
ULTIMATELY RESULT IN FREEZING DRIZZLE. THANKS TO THE RAPID SPEED OF
ANY SOURCES OF LIFT...AMOUNTS WILL STRUGGLE TO MEASURE AND HAVE GONE
WITH POPS AT OR BELOW 50PCT FOR THE REGION. BY 9PM...PCPN IS
EXPECTED TO LEAVE OR COME TO AN END OVER THE STL METRO AREA AND
AREAS TO THE NW...WHILE THE PCPN SHOULD END BY MIDNIGHT FOR AREAS TO
THE SE. NAM SUGGESTS THAT PCPN MAY BE MORE SUBSTANTIAL AND HANG ON
LONGER DUE TO THE SLOWER EWD MOVEMENT OF THE DEVELOPING SFC LO...
WHICH WILL LINGER LO LEVEL CONVERGENCE FOR LONGER WHICH WILL DRIVE
THE FZDZ. THIS SOLUTION OVERALL REJECTED FOR ITS SLOWER MOVEMENT...
BUT CONSIDERING HOW THE SYSTEM WAS STILL JUST COMING ONSHORE AT 00Z
THIS EVENING...IF THIS PLAYS OUT...IT WILL RESULT IN MORE
SUBSTANTIAL ICE ACCRETION.
PREFERRED WARMER MOS TEMPS ON SATURDAY AS DECENT AMOUNT OF SUNSHINE
EXPECTED. STRENGTHENING S FLOW ON SUNDAY WILL ALLOW TEMPS TO SURGE
WELL ABOVE AVERAGE THANKS TO RISING TEMPS THE NIGHT BEFORE.
QUESTIONABLE AMOUNTS OF STRATUS WITH INCREASED MOISTURE MAY RESULT
IN LOWER MET MOS NUMBERS PANNING OUT. CDFNT WILL THEN COME THRU
LATE IN THE DAY...AND SIMILAR TO WHAT WE ARE GOING TO SEE TODAY...
EVERYTHING COMES TOGETHER BRIEFLY FOR A SHORT-LIVED PCPN EVENT LATE
IN THE DAY...BUT WITH MUCH WARMER TEMPS...THIS WILL BE RAIN. ECMWF
EVEN GOES SO FAR TO SUGGEST THUNDER POTENTIAL.
AFTER ANOTHER QUIET PERIOD EARLY NEXT WEEK...ECMWF AND GFS DIVERGE
SIGNIFICANTLY ON WHAT TO DO WITH THE NEXT BIG WRN CONUS SYSTEM.
ECMWF CUTS IT OFF INTO NRN OLD MEXICO...WHILE GFS KEEPS IT AS A
STRONG PROGRESSIVE WAVE THAT WILL PUSH THRU THE FA DURING
WEDNESDAY-THURSDAY. WHILE ECMWF EVEN PUSHES THRU A GREATLY REDUCED
NRN STREAM SYSTEM AT THIS TIME...NEEDLESS TO SAY...LO CONFIDENCE
CONTINUES FOR THE MEDIUM RANGE. MAINTAINED LO CHC POPS FROM
PREVIOUS FCST. TEMPS SHOULD BE NOT TOO FAR AWAY FROM AVERAGE.
TES
&&
.AVIATION...
/1101 AM CST FRI JAN 20 2012/
LOCAL WRF AND RUC MODEL RUNS THIS MORNING ARE TRENDING THE
FORECAST TOWARD A MORE ICY LATE AFTERNOON/EVENING SOLUTION FOR
LOCATIONS ALONG AND SOUTH OF I-44 CORRIDOR IN MISSOURI AND I-70 IN
ILLINOIS. ATMOSPHERE WILL CONTINUE TO SATURATE THIS AFTERNOON WITH
PERSISTENT LOW LEVEL MOISTURE CONVERGENCE. RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET WILL PROVIDE ADDITIONAL LIFT LATE THIS
AFTERNOON TO PRODUCE A BAND OF FREEZING DRIZZLE OR LIGHT FREEZING
RAIN FROM THE OZARKS NORTHEAST TOWARD THE ST. LOUIS METRO AREA.
THIS BAND WILL EXPAND WITH TIME THIS EVENING TO THE EAST ACROSS
SOUTHERN ILLINOIS BEFORE EXITING THE CWA AROUND 06Z. ICE
ACCUMULATION SHOULD REMAIN BELOW ONE TENTH OF AN INCH.
OTHERWISE...EAST WIND WILL BECOME NORTH THROUGH THE PERIOD. SHOULD
SEE IMPROVING CONDIITONS AFTER MIDNIGHT WITH SKIES SCT OUT.
SPECIFICS FOR KSTL...
FREEZING DRIZZLE OR LIGHT FREEZING RAIN WILL DEVELOP THIS
AFTERNOON AND IMPACT THE TERMINAL THIS EVENING BETWEEN 23Z AND
02Z. CEILING WILL FALL TO LOW END MVFR WITH LOCAL REDUCTIONS IN
VISIBILITY THIS EVENING. EAST WIND WILL BECOME NORTH THROUGH THE
PERIOD. ICE ACCUMULATION SHOULD REMAIN LESS THAN A TENTH OF AN
INCH...BUT AMBIENT TEMPERATURES IN THE 20S WILL CAUSE UNTREATED
RUNWAYS TO BECOME VERY SLICK.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR CRAWFORD MO-FRANKLIN MO-IRON MO-JEFFERSON MO-
MADISON MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST.
LOUIS CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WASHINGTON MO.
IL...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR BOND IL-CLINTON IL-FAYETTE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
318 PM CST FRI JAN 20 2012
.SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
.LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.PREV DISCUSSION... /ISSUED 1143 AM CST FRI JAN 20 2012/
AVIATION...18Z KGRI TAF. VFR CONDITIONS EXPECTED THROUGH THE NEXT
24 HOURS. HIGH LEVEL DECKS WILL LIKELY PERSIST THROUGH THIS
EVENING...WITH DIMINISHING CLOUDS EXPECTED THEREAFTER. SURFACE
WINDS WILL GENERALLY REMAIN LIGHT AND VARIABLE THROUGH THE NEXT
FEW HOURS...BUT BECOME MORE ESTABLISHED FROM THE NORTH AT AROUND
13KTS TOWARDS 21Z. SURFACE WINDS WILL THEN BECOME LIGHT AND
VARIABLE OVERNIGHT...AND THEN INCREASE FROM THE SOUTH DURING THE
DAY SATURDAY. VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE
NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...BRYANT
LONG TERM...KING
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1253 PM EST FRI JAN 20 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE MIDWEST WILL MOVE TO THE EAST AND SETTLE OVER
NEW YORK STATE THIS AFTERNOON. ANY ONGOING LAKE EFFECT FLURRIES WILL
END AS THE HIGH BUILDS ACROSS THE AREA. LOW PRESSURE TRACKING
ACROSS THE LOWER OHIO VALLEY WILL BRING ANOTHER BATCH OF SNOWFALL
TONIGHT...BEFORE HIGH PRESSURE BRINGS ANOTHER PERIOD OF QUIETER
WEATHER WITH A WARM UP BY THE END OF THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE CONTINUES MOVE ACROSS THE REGION THIS AFTERNOON WITH
LOWERING INVERSION HEIGHTS WITH MAINLY FLURRIES NEAR THE LAKES.
TONIGHT...THE RIDGE WILL SLIDE OFF THE NEW ENGLAND COAST WHILE
LOW PRESSURE LIFTS NORTHEAST TOWARD THE LOWER OHIO VALLEY. WILL BE
SPEEDING UP THE TIMING OF THE PRECIP BY A FEW HOURS WITH THE NEXT
FORECAST UPDATE BASED OFF OF OBSERVATIONS AND HRRR RUNS. FORECAST SNOW
AMOUNTS LOOK GOOD...WITH A SUBTLE BUMP LATE TONIGHT ALONG THE
IMMEDIATE LAKE ONTARIO SHORE DUE TO SOME LAKE ENHANCEMENT...BUT
WITH GENERALLY LIGHT WINDS...THIS WILL BE HARDLY NOTICEABLE.
AN INVERTED SURFACE TROUGH EXTENDING NORTH OF THE PARENT LOW WILL
HELP TO FOCUS LOW LEVEL MOISTURE WHICH WILL BE INCREASING ON THE
NOSE OF A 40 TO 50 KNOT LOW LEVEL JET. THE INCREASING LOW LEVEL
THETA-E ADVECTION WILL COMBINE WITH ADDED LIFT FROM AN UPPER LEVEL
JET THAT WILL BE IN PLACE OVER NEW YORK STATE. THE RESULTING LARGE
SCALE LIFT WILL ALLOW SNOW TO SPREAD NORTH ACROSS THE AREA THIS
EVENING. STILL LOOKS LIKE THE HIGHEST SNOW ACCUMULATIONS WILL BE
SEEN ACROSS OUR THREE SOUTHERN TIER COUNTIES...WHERE A WINTER
WEATHER ADVISORY WILL BE ISSUED FOR LOW END ADVISORY
ACCUMULATIONS.
EAST OF LAKE ONTARIO...EXPECT A GENERAL SOUTH TO NORTH DECREASE IN
SNOWFALL TOTALS. A RELATIVELY WEAK PRESSURE GRADIENT OVER THE
LOWER LAKES MEANS THAT WINDS WILL NOT HAVE ANYWHERE NEAR THE
IMPACT THAT WAS FELT FELT THURSDAY.
WITH THE SYSTEM RACING EAST...WILL ALSO SPEED UP THE END TIME OF
THE PRECIP OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
LOW PRESSURE WILL CONTINUE TO TRACK EASTWARD ON SATURDAY...WITH
LINGERING SNOW EXPECTED TO END QUITE QUICKLY. MODEL SOUNDING
INDICATE A PERIOD OF LOW LEVEL MOISTURE WITH A WEAK UPSLOPE
NORTHERLY FLOW WHILE UPPER LEVEL MOISTURE RACES OFF TO THE EAST.
WILL ADD A POSSIBILITY OF SOME FREEZING DRIZZLE TO THE FORECAST.
WITH LACKING MOISTURE ALOFT...DO NOT EXPECT ANY LAKE EFFECT SATURDAY.
HIGH PRESSURE WILL BUILD ACROSS THE REGION SATURDAY NIGHT...THEN
THE HIGH WILL MOVE EASTWARD ACROSS NEW ENGLAND ON SUNDAY. LOWS ON
SATURDAY NIGHT ARE A BIT TRICKY...WITH THE NAM HANGING ONTO LOW
LEVEL MOISTURE THROUGH MUCH OF THE NIGHT...WHILE THE GFS IS MORE
BULLISH IN CLEARING THINGS OUT. FOR NOW...WILL HEDGE LOWS A
BIT...WITH BOTH LOW AND HIGH CLOUDS POSSIBLY LIMITING RADIATIONAL
COOLING. THE PERIOD WILL BE DRY...WITH WARMER TEMPERATURES BEHIND
THE HIGH ON SUNDAY. HIGHS SHOULD RISE INTO THE 30S ACROSS THE
REGION.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A SIGNIFICANT AREA OF LOW PRESSURE WILL TRACK ACROSS THE UPPER LAKES
EARLY IN THE LONG TERM PERIOD...HOWEVER THE EXACT TRACK AND TIMING
OF THE LOW REMAINS UNCERTAIN. THE MAIN CHALLENGE HERE IS THAT SOME
MODELS (00Z EUROPEAN/GGEM) CLOSE OFF THE LOW ALOFT QUITE
QUICKLY...WHICH SLOWS THE TRACK AND INTENSIFIES THE LOW.
MEANWHILE...OTHER MODELS (00Z GFS/NAM) KEEP IT AN OPEN WAVE ALOFT
LONGER...LIFTING THE LOW TO OUR NORTH SIGNIFICANTLY FASTER. ITS
INTERESTING TO NOTE THAT LOOKING AT THE GFS ENSEMBLE MEMBERS...FEW
IF ANY ARE IN AGREEMENT WITH THE GGEM/EURO. THE EVENTUAL IMPACT ON
OUR REGION WILL LARGELY BE THE SAME...WITH TIMING THE MAIN ISSUE.
WILL CONTINUE TO USE A CONSENSUS AMONG THE GFS/GGEM/EUROPEAN.
REGARDLESS OF WHICH MODEL IS CORRECT ON TIMING...THIS SYSTEM WILL
BRING THREE THINGS TO WESTERN NEW YORK...WINDY CONDITIONS...RAIN
SHOWERS...AND WARM TEMPERATURES. MUCH LIKE LOW PRESSURE EARLIER THIS
WEEK...A STRONG SSE FLOW ALOFT WILL MOVE IN AHEAD OF THIS SYSTEM.
WINDS WILL INCREASE SUNDAY NIGHT AND MONDAY AHEAD OF THE
FRONT...MAINLY ACROSS HIGHER TERRAIN...AND IN FAVORABLE FUNNELING
LOCATIONS NEAR THE CHAUTAUQUA RIDGE AND BLACK RIVER VALLEYS. THEN
WINDS WILL SHIFT TO THE SW BEHIND THE FRONT...FOCUSING STRONGEST
WINDS ALONG THE NIAGARA FRONTIER. IN EACH CASE...WIND GUSTS TO
ADVISORY CRITERIA (IN EXCESS OF 45 MPH) ARE POSSIBLE...WITH EVEN
STRONGER GUSTS POSSIBLE DEPENDING ON HOW CLOSE THE LOW TRACKS...AND
HOW STRONG IT TURNS OUT TO BE.
AHEAD OF THIS FRONT...TEMPERATURES WILL WARM SIGNIFICANTLY. AS IS
OFTEN THE CASE...EXPECT ALL GUIDANCE IS UNDER-DOING THIS. EXPECT
WARMEST TEMPERATURES WILL LIKELY BE MONDAY MORNING...JUST AHEAD OF
THE CONSENSUS TIMING OF FROPA. WILL FORECAST WIDESPREAD UPPER
40S...WITH LOWER 50S ALONG THE LAKE ERIE SHORELINE AND NIAGARA
FRONTIER...WHERE DOWNSLOPING SHOULD AID IN WARMING.
OTHERWISE...EXPECT A ROUND OF SHOWERS WITH THE FRONT. THIS WILL POSE
A MODEST THREAT FOR FLOODING...AS RECENT SNOWFALL IS LIKELY TO MELT.
HOWEVER...QPF WITH THE FROPA DOES NOT APPEAR TO BE TOO GREAT...WHICH
MAY LIMIT RISES IN THE CREEKS. WILL ALSO HAVE TO WATCH FOR ICE BUILD
UP...WITH RECENT CREEK RISES CAUSING SOME MODEST ICE BUILD UPS ON A
FEW CREEKS. THIS EVENT MAY SWEEP OUT THE CREEKS...LEAVING MANY ICE
FREE IN LATE JANUARY.
FOLLOWING THE PASSAGE OF MONDAY`S COLD FRONT...SEASONABLY COOLER AIR
WILL FILTER BACK INTO THE REGION MONDAY NIGHT AND TUESDAY ALONG WITH
A CYCLONIC FLOW OF FAIRLY DEEP WRAPAROUND MOISTURE. THIS WILL RESULT
IN A CONTINUATION OF SCATTERED SHOWERS...WITH PTYPE TRANSITIONING
BACK FROM RAIN TO SNOW SHOWERS AS TEMPS COOL. THIS SAID...TEMPS
ALOFT NOW ONLY LOOK TO DROP TO ABOUT -10C AT THEIR COLDEST ON
TUESDAY...WHICH MAY MAKE IT TOUGH FOR ANY LAKE RESPONSE AT ALL TO
DEVELOP...EVEN OFF OF LAKE ONTARIO.
AFTER THIS...INCREASING RIDGING AND SUBSIDENCE WILL THEN BRING A
RETURN TO DRY CONDITIONS TUESDAY NIGHT AND WEDNESDAY...BEFORE THE
NEXT IN A SERIES OF QUICK-MOVING SYSTEMS APPROACHES THE AREA ON
THURSDAY. WITH A GENERALLY MILD AND PROGRESSIVE ZONAL FLOW
CONTINUING THROUGH MID TO LATE NEXT WEEK...TEMPS THROUGH THE BALANCE
OF THE EXTENDED WILL TEND TO REMAIN ON THE MILD SIDE OF NORMAL AND
FAVORABLE FOR MORE OF A RAIN OR RAIN/SNOW MIX...AND RATHER
UNFAVORABLE FOR ADDITIONAL LAKE EFFECT SNOW.
A SLOW MOVING LOW IS LIKELY TO DEVELOP IN THE GULF STATES ON
WEDNESDAY AND THURSDAY. THIS LOW MAY LIFT TOWARD OUR REGION...OR IT
MAY STAY TO THE SOUTH ON THURSDAY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL DETERIORATE THIS EVENING TO IFR IN -SN AS A LOW
PRESSURE SYSTEM MOVES ACROSS THE TN RIVER VALLEY AND OFF THE MID
ATLANTIC COAST BY 18Z SATURDAY. SOME FZDZ IS POSSIBLE FOR A FEW
HOURS ON THE BACK SIDE OF THE SYSTEM WITH CONTINUED IFR CONDITIONS
IN AN NORTHERLY UPSLOPE FLOW. SOME IMPROVEMENT POSSIBLE LATE
SATURDAY.
OUTLOOK...
SUNDAY...VFR.
MONDAY...MVFR/IFR WITH RAIN SHOWERS LIKELY.
TUESDAY...MVFR IN SCT SNOW SHOWERS.
WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE OVER THE MIDWEST WILL MOVE TO THE EAST AND CREST OF
NEW YORK STATE THIS AFTERNOON. THIS WILL ALLOW NORTHWEST WINDS TO
SUBSIDE FROM WEST TO EAST AS THE DAY WEARS ON.
AN AREA OF LOW PRESSURE IS FORECAST TO LIFT NORTH TOWARD THE LOWER
OHIO VALLEY TONIGHT...THEN SLIDE OFF THE VIRGINA COAST ON SATURDAY.
BASED ON THIS TRACK...LOOKS LIKE THE PRESSURE GRADIENT OVER THE
LOWER LAKES WILL STAY WEAK ENOUGH TO PRECLUDE SMALL CRAFT ADVISORY
CONDITIONS FROM SETTING UP. SOUTHERLY WINDS WILL START TO PICK UP
AGAIN ON SUNDAY AHEAD OF YET ANOTHER APPROACHING LOW PRESSURE
SYSTEM.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
SATURDAY FOR NYZ019>021.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP/ZAFF
NEAR TERM...TJP/ZAFF
SHORT TERM...APFFEL/ZAFF
LONG TERM...APFFEL/JJR
AVIATION...ZAFF
MARINE...APFFEL/TJP/ZAFF
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1229 PM CST FRI JAN 20 2012
.DISCUSSION...SYNOPTIC UPDATE AND AVIATION DISCUSSION BELOW.
.UPDATE...FOG AND HAZE PERSIST EARLY THIS AFTERNOON ACROSS LA
SALLE AND WEBB COUNTIES. SURFACE BOUNDARY EXPECTED TO DRIFT
EASTWARD THIS AFTERNOON AND CROSS RIO GRANDE RESULTING IN CLEARING
SKIES AND QUICKLY WARMING TEMPS. HAVE LOWERED FORECAST HIGHS FOR
WESTERN ZONES DUE TO DELAYED WARMING TODAY. HAVE ALSO LOWERED
WINDS ACROSS WESTERN HALF OF CWA AND INCREASED WINDS ACROSS
COASTAL LOCATIONS. STRONG LOW LEVEL JET OF 35 TO 40 KTS AT H925
EXISTS FROM KBRO NORTHEASTWARD TO KPKV AND SOME OF THESE HIGHER
WINDS ARE MIXING TO THE SURFACE. EXPECTING WINDS TO DECREASE BY
LATE AFTERNOON ACROSS EASTERN AREAS AS JET PULLS EASTWARD. UPDATED
PRODUCTS ALREADY OUT.
&&
.AVIATION...MIX OF MVFR/VFR CONDITIONS THIS AFTERNOON ALL
TERMINALS THEN BECOMING IFR/LIFR LATER TONIGHT...THEN BACK TO MVFR
BY LATE IN THE TAF FCST PERIOD. LOW STRATUS WITH IFR CIGS AT KLRD
EARLY THIS AFTERNOON SHOULD MIX OUT WITH SCT TO BKN CU TO EXIST AT
REMAINING TERMINALS. TONIGHT TO FEATURE LOW STRATUS AND FOG/BR
DEVELOPING...ESPECIALLY AFTER 06Z WITH IFR/LIFR CIGS/VSBYS
OCCURRING. WEAK FRONTAL BOUNDARY TO DRIFT SWRD THROUGH REGION
AROUND/SHORTLY AFTER 12Z SATURDAY WITH INCREASING VSBYS AND MVFR
CIGS AFTER FROPA. LIGHT AND VARIABLE WINDS THIS AFTN AT KLRD AND
SSW AND GUSTY ELSEWHERE. TONIGHT WINDS SHOULD BECOME LIGHT AND
THEN NRLY AFTER FROPA SAT MRNG.
&&
.PREV DISCUSSION... /ISSUED 1021 AM CST FRI JAN 20 2012/
DISCUSSION...DENSE FOG ADVISORY HAS BEEN EXTENDED/EXPANDED FOR
WESTERN TWO COUNTIES UNTIL 11AM CST. MOISTURE HAS POOLED THIS
MORNING ALONG HIGHER TERRAIN OF OLD MEX AND ALONG A BOUNDARY
LOCATED JUST WEST OF THE RIO GRANDE. RESULTANT FOG HAS DEVELOPED
DUE TO HIGH MOISTURE AND LIGHT WINDS. RUC AND NAM BOTH INDICATE
BOUNDARY SHOULD BEGIN TO MOVE EASTWARD SHORTLY ACTING AS A QUASI-
DRYLINE THIS AFTERNOON WITH FOG QUICKLY MIXING OUT BETWEEN 17 AND
18Z. AREA OBS AND WEBCAMS INDICATE FOG MAY BE BEGINNING TO MIX OUT
AS OF WRITING AND WILL CONTINUE TO MONITOR TRENDS. OTHER UPDATES
TO FORECAST THIS MORNING HAVE BEEN TO INCREASE DEWPOINT VALUES FOR
TODAY AND TO ALTER SKY COVER. MAX TEMPS ACROSS WESTERN AREAS WILL
BE DEPENDENT ON HOW FAR EAST SAID BOUNDARY MOVES THIS AFTERNOON
BUT FOR NOW HAVE LEFT FORECAST VALUES INTACT. ADDITIONAL UPDATES
POSSIBLE AROUND MIDDAY. UPDATED PRODUCTS ALREADY SENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 82 64 78 62 79 / 10 10 10 10 10
VICTORIA 78 62 74 58 77 / 10 10 10 10 10
LAREDO 85 62 83 63 84 / 0 0 10 10 10
ALICE 85 63 81 61 82 / 10 0 10 10 10
ROCKPORT 74 64 72 62 73 / 10 10 10 10 10
COTULLA 80 55 81 57 81 / 0 0 10 10 10
KINGSVILLE 84 63 79 63 82 / 10 10 10 10 10
NAVY CORPUS 75 64 73 64 74 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
UPDATE/AVIATION...HART/79
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1021 AM CST FRI JAN 20 2012
.DISCUSSION...DENSE FOG ADVISORY HAS BEEN EXTENDED/EXPANDED FOR
WESTERN TWO COUNTIES UNTIL 11AM CST. MOISTURE HAS POOLED THIS
MORNING ALONG HIGHER TERRAIN OF OLD MEX AND ALONG A BOUNDARY
LOCATED JUST WEST OF THE RIO GRANDE. RESULTANT FOG HAS DEVELOPED
DUE TO HIGH MOISTURE AND LIGHT WINDS. RUC AND NAM BOTH INDICATE
BOUNDARY SHOULD BEGIN TO MOVE EASTWARD SHORTLY ACTING AS A QUASI-
DRYLINE THIS AFTERNOON WITH FOG QUICKLY MIXING OUT BETWEEN 17 AND
18Z. AREA OBS AND WEBCAMS INDICATE FOG MAY BE BEGINNING TO MIX OUT
AS OF WRITING AND WILL CONTINUE TO MONITOR TRENDS. OTHER UPDATES
TO FORECAST THIS MORNING HAVE BEEN TO INCREASE DEWPOINT VALUES FOR
TODAY AND TO ALTER SKY COVER. MAX TEMPS ACROSS WESTERN AREAS WILL
BE DEPENDENT ON HOW FAR EAST SAID BOUNDARY MOVES THIS AFTERNOON
BUT FOR NOW HAVE LEFT FORECAST VALUES INTACT. ADDITIONAL UPDATES
POSSIBLE AROUND MIDDAY. UPDATED PRODUCTS ALREADY SENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 82 64 78 62 79 / 10 10 10 10 10
VICTORIA 78 62 74 58 77 / 10 10 10 10 10
LAREDO 87 62 83 63 84 / 0 0 10 10 10
ALICE 85 63 81 61 82 / 10 0 10 10 10
ROCKPORT 74 64 72 62 73 / 10 10 10 10 10
COTULLA 85 55 81 57 81 / 0 0 10 10 10
KINGSVILLE 84 63 79 63 82 / 10 10 10 10 10
NAVY CORPUS 75 64 73 64 74 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 11 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: LA SALLE...WEBB.
GM...NONE.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
254 PM CST FRI JAN 20 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
254 PM CST FRI JAN 20 2012
MAIN FORECAST CONCERNS THIS PACKAGE...SN/FZRA CHANCES SUN...MAINLY
SNOW CHANCES SUN NIGHT/MON...TEMPERATURES THRU THE PERIOD.
18Z DATA ANALYSIS HAD A BROAD AREA OF LIGHT TO MDT SNOW MOVING EAST
ACROSS SOUTHERN MN/WI AND NORTHERN IA INTO NORTHERN IL. SNOW
TAPERING OFF ALONG/WEST OF I-35 EARLY THIS AFTERNOON AS LOWER LEVEL
MOISTURE TRANSPORT/WARM ADVECTION INTO A RATHER TIGHT/COLD THERMAL
ZONE AND DIVERGENCE ALOFT IN RIGHT ENTRANCE REGION OF A 500 AND
300MB JET MAX TRANSLATE EAST OF THE AREA. WV IMAGERY SHOWED THE WEAK
MID LEVEL SHORTWAVE AND TROUGH MOVING ACROSS MN/IA. WITH DEEP CLOUDS
AND LIGHT WINDS...18-19Z TEMPS ACROSS MUCH OF MN/IA/WI REMAINED ON
THE COLD SIDE...MOSTLY IN THE SINGLE DIGITS ABOVE ZERO.
NO LARGE ERRORS NOTED IN 20.12Z MODELS INITIALIZATIONS. SOLUTIONS
REASONABLY SIMILAR THRU 12Z SUN. FOR SUN THRU MON NIGHT MODELS THEN
DIVERGE INTO TWO CAMPS WITH THE HANDLING OF THE NEXT STRONGER SYSTEM
TO IMPACT THE UPPER MIDWEST...THE FASTER NCEP VS. SLOWER/STRONGER
NON-NCEP SOLUTIONS. DPROG/DT OF 500MB HGTS AT 20.12ZS SHOWED MODEL
RUNS OF 18.12Z AND 19.12Z VERIFIED RATHER WELL ACROSS NOAM/EASTERN
PAC...WITH A TREND TOWARD A BLEND OF THE EARLIER RUNS. THRU TONIGHT/
SAT MODELS TREND IS TOWARD STRONGER OF THE EARLIER RUNS WITH THE
NEXT TROUGH DIGGING INTO THE CENTRAL/SOUTHERN ROCKIES. GOOD
CONSISTENCY FOR SHORTWAVE RIDGING TO BUILD ACROSS THE UPPER MIDWEST
TONIGHT/SAT. TREND CONTINUES TO FAVOR STRONGER OF EARLIER SOLUTIONS
SAT NIGHT/SUN AS THE ROCKIES TROUGH EJECTS INTO THE CENTRAL/SOUTHERN
PLAINS. MODELS QUICKLY DIVERGE WITH THE EVOLUTION OF THE TROUGH AS
IT LIFTS ACROSS THE MID/UPPER MS VALLEY SUN NIGHT/MON...WITH NAM/GFS
OFFERING A FASTER/MORE OPEN WAVE SOLUTION AND UKMET/ECMWF/GEM
OFFERING A SLOWER/STRONGER MORE CLOSED 500MB LOW SOLUTION. TREND
SEEMS TO FAVOR THE SLOWER/STRONGER SOLUTIONS SUN NIGHT/MON. THE
BETTER RUN-TO-RUN CONSISTENCY IN THE SUN-MON TIME-FRAME SHOWN BY
ECMWF. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL QUITE GOOD SFC
MASS FIELDS OVER THE CENTRAL CONUS AND WITH THE SNOW MOVING ACROSS
THE REGION TODAY. PER WV IMAGERY...MODEL HAVE THE GENERAL IDEA OF
THE SHORTWAVE TROUGH MOVING ACROSS MN/IA BUT DIFFER ON ACTUAL
SHORTWAVE DETAILS. ALL APPEAR REASONABLE WITH THE NEXT ENERGY
APPROACHING THE WEST COAST. NO CLEAR MODEL FAVORITE BASED ON THE 18Z
ANALYSIS...BUT WITH THE BETTER RUN-TO-RUN CONSISTENCY SHOWN BY THE
ECMWF...FAVORED A MODEL COMPROMISE WEIGHTED TOWARD THE ECMWF
ESPECIALLY IN THE SUN NIGHT/MON TIME-FRAME. SHORT TERM FCST
CONFIDENCE GENERALLY GOOD TONIGHT INTO SUN...THEN AVERAGE SUN
NIGHT INTO MON NIGHT WITH THE MODELS IN TWO CAMPS.
FOR THE SHORT TERM...FORCING/LIFT/SNOW EXITING EAST OF THE AREA
RATHER QUICKLY AT MID AFTERNOON AND WAS ALREADY ENDING WEST OF A
KEAU-KALO LINE AS OF 20Z. WILL CANCEL WESTERN PORTIONS OF THE
WINTER WEATHER ADVISORY WEST/NORTH OF KLSE WITH THE AFTERNOON
PACKAGE ISSUANCE IF NOT BEFORE. BIG QUESTION TONIGHT BECOME CLOUD
COVER NOT AND IMPACTS ON LOW TEMPS. SFC RIDGE AXIS WITH LIGHT/CALM
WINDS OVER THE FRESH SNOW COVER WOULD ALLOW TEMPS TO PLUMMET WELL
BELOW ZERO TONIGHT. IF CLOUD COVER WOULD REMAIN ALL NIGHT...LOWS
WOULD BE MORE IN THE ZERO TO -5F RANGE. LOOKING UPSTREAM...PLENTY OF
LOW TO MID CLOUDS PRESENT...AND PLENTY OF THIN SPOTS/HOLES IN THOSE
CLOUD DECKS. WILL TREND TOWARD THE MIDDLE FOR NOW AND PASS ALONG
CONCERNS TO EVENING CREW TO WATCH THE CLOUD TRENDS AND POTENTIAL
LOWS TONIGHT. SOUTH/SOUTHWEST FLOW AND MDT/STRONG LOW LEVEL WARM
ADVECTION QUICKLY RETURN ON SAT AS THE NEXT LEE TROUGH DEVELOPS IN
THE CENTRAL/NORTHERN PLAINS. 850MB TEMPS CLIMB TO NEAR/ABOVE 0C BY
LATE SAT AND FOR SAT NIGHT AS THE SFC-MID LEVEL TROUGH MOVE EAST.
MID/HIGH LEVEL MOISTURE/INCREASING HIGH CLOUDS AHEAD OF THE TROUGH
SPREAD ACROSS THE AREA FOR SAT AFTERNOON/NIGHT. MODEL SOUNDINGS
INDICATE A STRENGTHENING LOW LEVEL INVERSION NEAR 900MB OVER THE
AREA SAT/SAT NIGHT. THIS WITH THE INCREASING CLOUDS WILL LIMIT THE
WARMUP OVER THE SNOWCOVER SAT. WITH CONTINUED SOUTHERLY FLOW AND
POTENTIAL FOR A LOW CLOUD BLANKET SAT NIGHT...LOWS LIKELY TO BE
EARLY IN THE EVENING WITH STEADY/SLOWLY RISING TEMPS MUCH OF THE
NIGHT. FIRST IMPACTS/PRECIP CHANCES WITH THE NEXT TROUGH ARRIVE SUN.
WITH THE SNOW COVER AND CLOUDS...HAVE DOUBTS ABOUT SUN HIGHS RISING
MUCH ABOVE UPPER 20S/LOW 30S. WITH POTENTIAL FOR 850MB TEMPS TO BE
ABOVE 0C AHEAD OF THE TROUGH ON SUN...AND COLD/FROZEN GROUND
SURFACES...CONTINUED THE -FZRA CHANCE OVER THE SOUTH 3/4 OF THE FCST
AREA. MID LEVEL TROUGH MOVES INTO THE REGION SUN NIGHT WITH THE
COLUMN COOLING TO BELOW 0C. BULK OF ANY PRECIP SUN NIGHT LOOKING TO
BE SNOW BUT CONTINUED A -FZRA CHANCE OVER THE SOUTHEAST END OF THE
FCST AREA WHERE THE COOLING WILL BE LAST TO OCCUR. WITH DIVERGENCE
OF SOLUTIONS...FAST NAM/GFS VS. SLOWER UKMET/GEM/ECMWF...VAST
DIFFERENCES IN POTENTIAL SENSIBLE WEATHER LATER SUN NIGHT INTO MON
NIGHT. WITH TREND FAVORING THE MORE CONSISTENT ECMWF...RAISED PRECIP
CHANCES SUN NIGHT INTO THE 45 TO 65 PERCENT RANGE AND SNOW CHANCES
MON INTO THE 25 TO 45 PERCENT RANGE FOR NOW. IF TREND CONTINUES
STRONGLY TOWARD THE ECMWF CAMP SUN NIGHT/MON...PRECIP CHANCES THESE
PERIODS WILL NEED TO BE TRENDED TO 70 PERCENT OR HIGHER FOR MUCH OF
THE FCST AREA. FOR NOW THE MID-RANGE PROBABILITIES SUN NIGHT/MON
BLEND WELL WITH THE NEIGHBORING GRIDS. TROUGH AXIS LIFTS NORTHEAST
OF THE AREA MON NIGHT WITH SUBSIDENCE/DRYING SPREADING ACROSS MN/IA
AND MUCH OF WI.
FAVORED COLDER OF GUIDANCE LOWS/HIGHS TONIGHT THRU SAT NIGHT.
FAVORED A BLEND OF GUIDANCE HIGHS/LOWS FOR SUN THRU MON NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY
254 PM CST FRI JAN 20 2012
20.00Z MEDIUM RANGE MODELS IN REASONABLY GOOD AGREEMENT TUE AS ONE
TROUGH EXITS EAST OF THE REGION AND SHORTWAVE RIDGING ALOFT BUILDS
ACROSS THE UPPER MIDWEST. GFS REMAINS A MORE PROGRESSIVE SOLUTION
BUT ITS 20.06Z RUN TRENDED SLOWER/CLOSER TO THE GEM/UKMET/ECMWF
CONSENSUS. CONSENSUS IMPROVING FOR A MDT MID LEVEL TROUGH TO MOVE
ACROSS THE REGION WED. SOLUTIONS BEGIN TO DIVERGE ON THE DETAILS
THU/FRI BUT SOME CONSENSUS FOR A SECOND NORTHERN STREAM TROUGH
TO PUSH ACROSS THE UPPER MIDWEST THU THEN YET ANOTHER SHORTWAVE
TROUGH TO APPROACH ALONG THE US/CAN BORDER IN QUASI-ZONAL FLOW
FRI. BETTER RUN-TO-RUN CONSISTENCY THRU THE TUE-FRI TO ECMWF. WITH
BETTER CONSISTENCY...GFS TRENDING TOWARD IT AND PMDEPD SIDING TOWARD
THE ECMWF/ENSEMBLE MEAN...ALSO FAVORED A BLEND WEIGHTED TOWARD THE
ECMWF. GIVEN WED-FRI PORTION OF THE FCST DEPENDENT ON PROGRESSIVE
SHORTWAVES IN A RATHER FLAT...FAST FLOW...LONG TERM FCST CONFIDENCE
AVERAGE AT BEST THIS CYCLE. TUE LOOKS DRY/SEASONAL WITH SFC HIGH
PRESSURE RIDGING AND THE SHORTWAVE RIDGING ALOFT OVER THE WESTERN
GREAT LAKES. -SN CHANCE CENTERED ON WED REASONABLE WITH THE BETTER
CONSENSUS FOR A MDT STRENGTH MID LEVEL SHORTWAVE TROUGH TO BE MOVING
ACROSS THE REGION. PLENTY OF MODEL DETAIL DIFFERENCE WITH
STRENGTH/TIMING OF THE NEXT WEAK TO MDT SHORTWAVE IN THE FLOW FOR
THU...GFS FASTER/WEAKER...ECMWF SLOWER/STRONGER. 20.12Z GFS/ECMWF
SUPPORT THEIR RESPECTIVE TRENDS THU. SOME CONSISTENCY FOR A SFC
TROUGH/FRONT TO BE PUSHING ACROSS THE AREA FRI. MODEL CONSENSUS
LEAVES MUCH OF THU/FRI DRY FOR NOW AND THIS REASONABLE PENDING
BETTER/MORE CONSISTENT MODEL SIGNALS IN THE DAY 6/7 TIME-FRAME. WITH
MORE OF A ZONAL FLOW ACROSS THE NORTHERN CONUS NEXT WEEK AND NO
INTRUSIONS OF ARCTIC AIR...TEMPS FOR TUE-FRI LOOKING TO BE
NEAR/ABOVE NORMAL. THIS WELL TRENDED BY THE MODEL CONSENSUS DATA
SETS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1127 AM CST FRI JAN 20 2012
SHORT WAVE TROUGH MOVING OVER THE REGION THIS MORNING WILL BEGIN
TO PASS TO THE EAST DURING THE AFTERNOON AND EVENING. THE 20.12Z
NAM AND SEVERAL RUNS OF THE RUC INDICATE THE FORCING FROM THE SHORT
WAVE TROUGH IS AT IS MAXIMUM NOW AND WILL BE DECREASING FOR THE
REMAINDER OF THE DAY AS THE WAVE BEGINS TO MOVE AWAY. BASED ON RADAR
TRENDS...EXPECT THE VISIBILITY AT KRST TO COME UP TO AROUND A MILE
AND THEN HOLD THERE OR SLOWLY IMPROVE...BUT REMAIN IFR...UNTIL THE
SNOW ENDS LATE THIS AFTERNOON. KLSE WILL SEE THE VISIBILITY REMAIN
UNDER A MILE FOR A COUPLE OF MORE HOURS...BEFORE ALSO IMPROVING TO
AROUND A MILE. THE SNOW AT KLSE IS ALSO EXPECTED TO END VERY LATE
THIS AFTERNOON. CEILINGS EXPECTED TO COME UP TO MVFR AS THE
VISIBILITY GO TO A MILE AND THEN HOLD THERE THROUGH THE EVENING
UNTIL THE SURFACE RIDGE BUILDS IN FROM THE WEST TO SCATTER THE
CLOUDS OUT. ONCE THIS HAPPENS...VFR CONDITIONS THEN EXPECTED THROUGH
SATURDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
254 PM CST FRI JAN 20 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ042>044-053>055-061.
MN...NONE.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ011-029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1127 AM CST FRI JAN 20 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
300 AM CST FRI JAN 20 2012
ITS GOING TO SNOW ACROSS THE FORECAST AREA TODAY...WITH THE MAIN
QUESTIONS BEING HOW MUCH AND WHERE THE HIGHER TOTALS WILL BE FOUND.
THE UPPER LEVEL SHORTWAVE TROUGH HELPING TO BRING THE SNOW IS NOT
OVERLY APPARENT VIA THE LATEST WATERVAPOR IMAGERY...AND 20.00Z
MODEL RUNS POINT TO A SOMEWHAT WEAK...WEST-EAST ORIENTATED ELONGATED
WAVE MOVING ACROSS THE FORECAST AREA BETWEEN 15-00Z. QG CONVERGENCE
ISN/T ALL THAT IMPRESSIVE...BEST IN THE 850-700 MB LAYER AND ACROSS
IA/NORTHERN ILL. GOOD LOW LEVEL THERMODYNAMICS THOUGH...WITH
ISENTROPIC UPGLIDE ON THE 275-295 K SFC AND WARM AIR ADVECTION IN
THE 925-700 MB LAYER. AGAIN THOUGH...THIS IS STRONGEST ACROSS
IA/NORTHERN ILL. A NORTHEAST-SOUTHWEST RUNNING X-SECTION DOES
INDICATE SLOPING 2-D FRONTOGENETIC LIFT ACROSS THE FORECAST
AREA...STRONGEST THIS MORNING. SOME HINTS OF -EPV ACROSS THE TOP OF
THIS FRONTOGENETIC FORCING ACROSS THE SOUTHERN 1/2 OF THE
AREA...SUGGESTIVE THAT SOME ENHANCED BANDING COULD DEVELOP.
OVERALL...FORCING POINTS TO THE HIGHER ACCUMULATIONS ACROSS
NORTHEAST IA/SOUTHWEST WI TODAY. HOWEVER...A COUPLE QUESTIONS ADD
SOME COMPLEXITY TO THE SNOW POTENTIAL - OVERCOMING THE DRY AIR
ACROSS THE REGION AND WHERE THE DEEPER DENDRITIC GROWTH ZONE WILL
LIE.
20.00Z DVN/MPX SOUNDINGS SHOW A VERY DRY LOW LAYER THAT WILL HAVE TO
BE SATURATED BEFORE ANY SNOW CAN REACH THE GROUND. SECOND...BUFKIT
SOUNDINGS SHOW A VERY DEEP DENDRITIC ZONE GROWTH REGION...UPWARDS OF
15 KFT TO THE SFC...BUT THIS IS SHIFTED NORTH OF THE BETTER
FORCING...MORE AROUND THE I-90 CORRIDOR. 19.21Z SREF HAS THE HIGHEST
PROBABILITIES FOR 2 INCH/HOUR SNOW RATES ALSO IN THIS REGION. SO...A
SLIGHT DISCONNECT BETWEEN WHERE THE BETTER FORCING IS EXPECTED...AND
WHERE THE MORE FAVORABLE HIGH SNOW RATIO REGION WILL BE. AND
AGAIN...SNOW AMOUNTS WILL HAVE TO TAKE INTO CONSIDERATION THE
SATURATION THAT NEEDS TO OCCUR FIRST.
ALL THAT SAID...BELIEVE THE HIGHER TOTALS STILL LOOK GOOD ACROSS
NORTHEAST IA/SOUTHWEST WI. THERE IS A BIT LESS DRY AIR TO OVERCOME
IN THIS REGION AND IT WILL HAVE THE STRONGER FORCING THROUGH THE
DAY. 4 TO 6 INCHES ALSO LOOKS PROBABLE...BUT A FEW 7 INCH
TOTALS WOULD NOT SURPRISE. WILL STAY WITH THE ADVISORY FOR NOW...BUT
TRENDS WILL HAVE TO BE MONITORED. THE BULK OF THE SNOW SHOULD FALL
THIS MORNING.
SUNDAY PRESENTS ANOTHER FORECAST CHALLENGE AS A STRONGER UPPER LEVEL
TROUGH WORKS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...AND WARMER
AIR BRINGS THE THREAT OF MIXED WINTER PCPN INTO THE PICTURE. THERE
ARE DIFFERENCES WITH HOW THE MODELS HANDLE THIS SYSTEM...AND THEY
WOULD HAVE AN IMPACT ON THE FORECAST AREA. THE 20.00Z NAM AND GFS
ARE MORE PROGRESSIVE/NOT AS STRONG COMPARED TO THE EC/GEM...WITH THE
NAM THE QUICKEST OF THE MODELS. THE STRONGER AND SLOWER EC/GEM
RESULTS IN A DEEPENING SFC LOW CLOSER TO THE FORECAST AREA...AND AN
ENHANCED PCPN REGION AROUND/WEST OF THE LOW. BOTH OF THESE MODELS
HAVE PCPN IMPACTING AT LEAST THE EASTERN 1/2 OF THE FORECAST AREA
THROUGH 12Z MON WHILE THE GFS/NAM HAVE SHIFTED MOST OF THE
PCPN...AND MUCH SMALLER QPF AMOUNTS...EAST. TRENDS HAVE BEEN FARTHER
SOUTH IN THE GFS/EC OVER THE PAST FEW DAYS...THE GEM HAS JUMPED
AROUND A LOT...WHILE THE NAM HAS STAYED NORTH/WEAKER. CONFIDENCE
SHAKY WITH SUCH A VARIETY OF POSSIBILITIES...BUT WILL LEAN ON THE
MORE FAVORED SOUTHERN TRACK. THE EC LOOKS A BIT OVERDONE AND
ALTHOUGH PROBABLY TOO FAST...THE GFS SEEMS LIKE A DECENT COMPROMISE.
WILL LEAN ON A GFS/CONSENSUS SOLUTION IN THIS TIME FRAME FOR NOW.
ON THE FRONT END OF THIS SUNDAY SYSTEM...NORTHEAST-SOUTHWEST RUNNING
X-SECTIONS AND BUFKIT SOUNDINGS SUGGEST THAT THE MOISTURE WILL BE
SHALLOW...AND DEVOID OF ANY ICE. ANY PCPN WOULD BE LIQUID -
POTENTIALLY FREEZING BASED ON SFC TEMPS. HOWEVER...THIS DOESN/T LAST
LONG AS UPWARD SATURATION INTO ICE IS RATHER QUICK. SNOW APPEARS TO
BE THE MOST LIKELY PCPN TYPE WHEN THE BEST FORCING MOVES IN...SUNDAY
NIGHT. COULD STILL SEE A PERIOD OF SOME FREEZING PCPN OVER SOUTHWEST
WI SUN AFTERNOON/EVENING AS SOME LOW LEVEL WARMING COULD RESULT IN
RAIN...BUT HITS COLD GROUNDS FROM THE RECENT COLD SNAP ACROSS THE
REGION. CONFIDENCE IS LOW FOR THE VARIETY OF TYPES WITH THIS
SYSTEM...AND EXPECT REFINEMENT TO THE FORECAST OVER THE NEXT DAY OR
TWO AS MODELS BUILD SOME CONSENSUS.
.LONG TERM...MONDAY THROUGH THURSDAY
300 AM CST FRI JAN 20 2012
ANOTHER SHORTWAVE TROUGH LOOKS TO TRACK EAST ACROSS THE
PLAINS...EVENTUALLY SPINNING ACROSS THE REGION TUE-WED.
DIFFERENCES ON TIMING WITH THIS FEATURE...WITH THE GFS QUICKER THAN
THE EC. QPF IS KIND OF MEAGER VIA BOTH SOLUTIONS...BUT IT DOES LOOK
COLD ENOUGH FOR JUST SNOW. COULD SEE AN INCH OUT OF THIS QUICK
MOVING SHORTWAVE. WILL LEAN ON THE CONSENSUS SOLUTION FOR TIMING.
TEMPERATURES LOOK TO HOLD NEAR OR ABOVE NORMAL FOR MUCH OF THE NEW
WORK WEEK.
&&
.AVIATION...THROUGH 18Z SATURDAY
1127 AM CST FRI JAN 20 2012
SHORT WAVE TROUGH MOVING OVER THE REGION THIS MORNING WILL BEGIN
TO PASS TO THE EAST DURING THE AFTERNOON AND EVENING. THE 20.12Z
NAM AND SEVERAL RUNS OF THE RUC INDICATE THE FORCING FROM THE
SHORT WAVE TROUGH IS AT IS MAXIMUM NOW AND WILL BE DECREASING FOR
THE REMAINDER OF THE DAY AS THE WAVE BEGINS TO MOVE AWAY. BASED ON
RADAR TRENDS...EXPECT THE VISIBILITY AT KRST TO COME UP TO AROUND
A MILE AND THEN HOLD THERE OR SLOWLY IMPROVE...BUT REMAIN
IFR...UNTIL THE SNOW ENDS LATE THIS AFTERNOON. KLSE WILL SEE THE
VISIBILITY REMAIN UNDER A MILE FOR A COUPLE OF MORE HOURS...BEFORE
ALSO IMPROVING TO AROUND A MILE. THE SNOW AT KLSE IS ALSO EXPECTED
TO END VERY LATE THIS AFTERNOON. CEILINGS EXPECTED TO COME UP TO
MVFR AS THE VISIBILITY GO TO A MILE AND THEN HOLD THERE THROUGH
THE EVENING UNTIL THE SURFACE RIDGE BUILDS IN FROM THE WEST TO
SCATTER THE CLOUDS OUT. ONCE THIS HAPPENS...VFR CONDITIONS THEN
EXPECTED THROUGH SATURDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 AM CST FRI JAN 20 2012
WI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST TODAY FOR
WIZ041>044-053>055-061.
MN...WINTER WEATHER ADVISORY TO 6 PM CST TODAY FOR
MNZ086>088-094>096.
IA...WINTER WEATHER ADVISORY TO 6 PM CST TODAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04