000
FXUS61 KALY 080830
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
330 AM EST FRI MAR 8 2013
.SYNOPSIS…
STRONG LOW PRESSURE WELL OFFSHORE WILL MOVE OUT TO SEA THIS
EVENING…WITH SNOW ENDING THIS AFTERNOON OVER OUR REGION. HIGH
PRESSURE WILL BUILD ALONG THE EASTERN SEABOARD AT ALL LEVELS OF
THE ATMOSPHERE FOR THE WEEKEND BRINGING CONSIDERABLE SUNSHINE AND
SEASONABLE TEMPERATURES. A COLD FRONT WILL MOVE INTO THE REGION
AND STALL TO START THE WORKWEEK. LOW PRESSURE WILL DEVELOP ALONG
THE FRONT…WITH UNSETTLED WEATHER FOR THE FIRST PART OF THE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/…
RATHER IMPRESSIVE MOISTURE ENTRAINMENT FROM THE DEEP CYCLONE OVER
THE ATLANTIC WITH A SUB-TROPICAL CONNECTION PER THE H2O VAPOR LOOP
ANALYSIS. MEANWHILE…A WELL DEFINED UPPER LOW OVER THE KEYSTONE
STATE WAS ALSO ASSISTING WITH THE ADDITIONAL TRANSPORT OF MOISTURE
ALONG WITH ENHANCED DYNAMICS FOR THE SNOW WE ARE EXPERIENCING THIS
MORNING. MODEL DIAGNOSTICS FIELDS IN THIS ATYPICAL SITUATION FOR
ACCUMULATING SNOW POINT TOWARD MAX LIFT WITHIN THE DENDRITIC ZONE
BETWEEN 10K-15K FEET THROUGH THIS EARLY FRIDAY MORNING.
FURTHERMORE…2D FGEN FIELDS ALONG WITH MID LEVEL QG FORCING WILL
BE SURE TO KEEP THIS SNOW GOING THROUGH SUNRISE. SNOWFALL REPORTS
THUS FAR HAVE VARIED WITH THE BEST CONCENTRATION OF SNOWFALL PER
RADAR IMAGERY REMAINS ACROSS LITCHFIELD…BERKSHIRE AND THE
TACONICS. IN FACT…A CLOSER EXAMINATION OF THE METARS AND
STREAMLINES POINT TOWARD A MOHAWK-HUDSON CONVERGENCE INTO THE
CAPITAL REGION.
PER THE SHORT TERM NCEP MODEL SUITE…THE BEST LIFT WILL OCCUR
WITHIN A COUPLE OF HOURS OF SUNRISE. THEREAFTER…THE UPPER LOW
OVER PA DIVES SOUTHEAST AND EXITS THE CAPE MAY COASTLINE OF NJ BY
MID-LATE MORNING. THE ASSOCIATED QG FORCING AND DEFORMATION QUICKLY
SHIFT SOUTHEAST WHICH WILL ALLOW FOR DIMINISHING TRENDS FROM NORTH
TO SOUTH. THE BOUNDARY LAYER TEMPERATURES WILL ALSO CLIMB ABOVE
FREEZING RESULTING IN A MIXTURE OF RAIN/SNOW DEVELOPING BEFORE ALL
OF THE PRECIP ENDS THIS AFTERNOON. TOTAL SNOWFALL AMOUNTS FROM THIS
EVENT ARE LIKELY TO RANGE FROM 3-7 INCHES…ALTHOUGH…A FEW 8 INCH
REPORTS WOULD NOT BE A SURPRISE ACROSS THE HIGHER TERRAIN WHERE
FAVORABLE PERSISTENT UPSLOPE CONDITIONS HAVE OCCURRED. WE WILL
LEAVE HEADLINES IN PLACE AT THIS TIME.
WINDS WILL BECOME A BIT GUSTY TODAY AS THE COMBINATION OF TIGHT
PRESSURE GRADIENT AND MIXING LAYER HEIGHTS CLIMB TO NEAR 2K FEET
WHERE MID-UPR 20KTS RESIDES.
SUBSIDENCE QUICKLY OCCURS TOWARD FROM NORTH TO SOUTH TOWARD SUNSET
WITH CLEARING SKIES. THIS TOO WILL RELAX THE WIND FIELDS AS A
SURFACE HIGH SLIDES INTO THE REGION FROM THE WEST. A FRESH SNOWPACK
UNDER CLEARING SKIES AND LIGHT WINDS WILL RESULT IN NEAR IDEAL
RADIATIONAL COOLING WITH TEENS TO MID 20S EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/…
WEEKEND BEGINS WITH FAIRLY GOOD CONSISTENCY AMONG THE MODEL SUITE.
500HPA RIDGE AND SFC HIGH CREST OVER THE REGION…WITH RIDGE AXIS
MOVING EAST OF FCA DURING SUNDAY. RESULT WILL BE A SUNNY SAT AND
PS TO MS SUNDAY…WITH SOMEWHAT ABV NORMAL TEMPS.
ABV NORMAL TEMPS CONTINUE THROUGH THE PERIOD. THINGS BEGIN TO
DIVERGE SUN AFTN SLIGHTLY AND MORE SO INTO MONDAY. NEXT SYSTEM AN
ANNA TYPE CDFNT…MOVES INTO GRTLKS RGN SUNDAY…NAM BRINGS SOME
INCRG MID CLOUDS INTO RGN SUN AFTN…GFS LESS SO…AND GEM HOLDS
THIS OFF TILL LATE SUN NT. MOST OF THE GUID BRINGS THE CDFNT INTO
THE E GRTLKS MONDAY…WITH CHC -SHRA TWRD DAYBREAK OVER FCA. AFTER
THAT THINGS BEGIN TO REALLY SPREAD. NAM KEEPS THE SYSTEM PROGRESSIVE
AND MOVING ALONG THROUGHOUT THE FCA WITH A PERIOD POST CDFNT PCPN
AND SUGGEST A QUICK EXIT MON EVNG. 21UTC SREF ENSEMBLES ARE ALONG
THIS THINKING AS WELL. HWVR THE REST OF THE MODEL SUITE PLAY OUT
DIFFERENTLY AND ATTM I CONSIDER THE NAM AN OUTLIER.
THE GFS/HPC/GEM PHASE A STRONGER S STREAM SHORT WV WHICH RUNS
500HPA FLOW MORE SW-NE. CDFNT MOVES INTO RGN SUN NT AND STALLS
SW-NE FM SVT TO IPT. SFC LOW WV FORMS IN RESPONSE TO 500HPA
FORCING…AND ANNA FRONT EVOLVES INTO A WIDESPREAD STRATOFORM PCN
EVENT…MOSTLY RAIN MONDAY INTO TUE. MOST OF THE 18UTC GFS
ENSEMBLES ALSO SUPPORTED THIS SOLUTION.
THE GEM/ECMWF ARE SIMILAR AND FASTER IN THE SYSTEMS PROGRESSION
AND HAVE MUCH LESS SFC LOW DEVELOPMENT THAN THE GFS WITH THIS
SYSTEM…WITH BULK OF IT EXITING RGN MON NT. AT THIS POINT THIS IS
THE MID POINT SOLUTION BETWEEN THE NAM OFF TO THE RACES AND THE
GFS FULL BLOWN CYCLOGENISUS. HPC IS MIDWAY BETWEEN GFS/GEM. AT
THIS POINT ITS RN/SHRA HI CHC TO LKLY MONDAY AND MON NT. .
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/…
TUESDAY SFC CDFNT CLEARS FCA…USHERING IN A RETURN TO NORMAL
TEMPS. 500HPA CUT OFF LOW REMAINS OVER THE UPR GRTLKS WITH
SERIES OF TROFS ROTATING AROUND IT. TUES FCA WILL BE IN CAA
SUBSIDENCE AND DRY SLOT WITH TROF WELL WEST OF FCA. TEMPS WILL BE
NR NORMAL WITH VRBL CLOUDS. TUES NT AND WED TROF WILL MOVE ACROSS
FCA…WITH INCRG CLOUDS SCT SHRA-SHSN. WED NT IT MOVES EAST OF
RGN..WITH MORE TYPICAL WINTER WX..STRATO-CU…SCT -SHSN..SOME LK
RESPONSE BUT NOT TERRIBLY FAVORABLE FOR THAT. COLDER..BUT SEASONABLE
AIR SURGES INTO FCA BY END OF PERIOD WITH BLO NORMAL TEMPS TO END
EFP.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/…
IFR CONDITIONS WITH SNOW WILL CONTINUE OVER THE ENTIRE REGION
THROUGH THE NIGHT TIME PERIOD…AND GRADUALLY DIMINISH DURING THE
EARLY DAYLIGHT HOURS. BOTH THE CEILINGS AND VISIBILITIES SHOULD
IMPROVE FROM NORTH TO SOUTH TOWARD NOON WITH VFR CONDITIONS EXPECTED
BY MID-LATE AFTERNOON HOURS.
NORTH TO NORTHEAST WINDS TONIGHT WILL GRADUALLY BACK MORE INTO
THE NORTH AT AROUND 10 KT…THEN PICK UP FROM THE NORTH TO
NORTHWEST ON FRIDAY AT 10 TO 15 KTS WITH GUSTS OF 20 TO 25 KTS.
OUTLOOK…
FRI NT-SUN EVE…VFR. NO SIG WX.
SUN NT-TUE…VFR/MVFR. CHC RAIN SHOWERS/PERIOD OF -RA.
&&
.HYDROLOGY…
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS.
NO TIDAL FLOODING IS EXPECTED NEAR POUGHKEEPSIE AT THIS TIME BASED
ON THE LATEST FORECASTS FROM THE NERFC…AND THE LOW LEVEL WINDS BE
FROM THE NORTH TO NORTHEAST TONIGHT INTO TOMORROW.
TEMPERATURES ARE EXPECTED TO MODERATE TO ABOVE NORMAL ON THE
WEEKEND…HOWEVER WITH TEMPERATURES FALLING BELOW FREEZING AT
NIGHT…THERE WILL ONLY BE DIURNAL SNOWMELT.
A COLD FRONT AND PASSING LOW PRESSURE AREA WILL BRING SHOWERS TO
THE REGION MONDAY THROUGH TUESDAY WITH 0.25 TO 0.75 QPF MOSTLY AS
RAIN. THIS MAY ENHANCE SNOWMELT…BUT WITH TEMPERATURES TRENDING
COLDER TOWARD THE END OF THE WEEK…WILL ONLY RESULT IN WITHIN BANK
RISES.
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…WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY…WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ040-047-
048-051-054-058-061-063>066.
MA…WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT…WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS…SNYDER
NEAR TERM…BGM
SHORT TERM…SNYDER
LONG TERM…SNYDER
AVIATION…BGM
HYDROLOGY…BGM/SNYDER/WASULA
