FXUS61 KALY 031135
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
635 AM EST THU DEC 3 2009
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL TRACK FROM THE EASTERN GREAT LAKES
INTO NORTHERN NEW ENGLAND TODAY. A WARM FRONT WILL LIFT NORTH ACROSS
THE REGION EARLY THIS MORNING...FOLLOWED BY A COLD FRONT BY MIDDAY.
THESE FEATURES WILL TRIGGER SHOWERS AND POSSIBLE THUNDERSTORMS
THROUGH NOON...ALONG WITH GUSTY WINDS. COLDER BUT GENERALLY FAIR
WEATHER WILL FOLLOW IN THE WAKE OF THIS STORM THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 415 AM EST...AFTER A SIGNIFICANT LULL IN THE PRECIP...ANOTHER
SURGE OF MOD-HVY RAINFALL WAS ADVANCING NORTH NORTHEAST UP THE
HUDSON VALLEY AND SW NEW ENGLAND. THIS APPEARS TO BE IN ASSOCIATION
WITH AN EMBEDDED SHORTWAVE TRANSLATING NE...AS WELL AS WITHIN THE
RIGHT ENTRANCE OF A STRONG JETLET PASSING TO OUR N/W. WE EXPECT THIS
PERIOD OF MOD-HVY RAIN TO PERSIST FOR ABOUT 1-3 HOURS...ALONG WITH
PERHAPS A FEW RUMBLES OF THUNDER GIVEN PREVIOUS LIGHTNING
STRIKES...AND MODEL SHOWALTER INDICES OF -1 TO -2 PASSING ACROSS THE
REGION.
HOWEVER...OF GREATER SIGNIFICANCE WILL BE THE CONVECTIVE
LINE...CURRENTLY CROSSING CENTRAL PA. THIS APPEARS TO BE IN
ASSOCIATION WITH TAIL END OF POWERFUL VORT MAX...THE REMNANTS OF
PREVIOUS UPPER LEVEL GULF COAST LOW...WHICH IS CURRENTLY CROSSING
WESTERN PA. THIS LINE IS EXPECTED TO TRANSLATE NE...ACROSS MUCH OF
THE REGION SHORTLY AFTER DAYBREAK...THROUGH ABOUT 10 AM EST. WITHIN
THIS LINE...THERE IS THE POTENTIAL TO MIX STRONG WINDS TO THE SFC.
WE CAN NOT RULE OUT ISOLATED DAMAGING WINDS WITHIN THIS LINE. SINCE
THIS IS CLEARLY A CONVECTIVE FEATURE...WE WILL HANDLE STATEMENTS
WITH SPS/S AND/OR SVR/S AS NECESSARY.
IN THE WAKE OF THIS...GRADIENT WINDS WILL INCREASE RAPIDLY FROM THE
SW TO W...BUT ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS. WE STILL
COULD SEE SOME GUSTS REACH 40-45 MPH...ESP ACROSS THE WESTERN
DACKS...AND ALSO LATER THIS AFTERNOON/EVENING WITHIN THE MOHAWK
RIVER VALLEY AND CAPITAL REGION AS WINDS GRADUALLY VEER INTO A MORE
FAVORABLE W/WNW DIRECTION TOWARD SUNSET FOR CHANNELING DOWN THE
MOHAWK RIVER VALLEY.
SKIES SHOULD BRIEFLY BECOME PARTLY TO PERHAPS MOSTLY SUNNY LATER
THIS MORNING...ESP FROM THE HUDSON RIVER VALLEY EASTWARD...BEFORE
CLOUDS REDEVELOP FROM W TO E DURING THE AFTERNOON WITHIN
STRENGTHENING COLD ADVECTION.
AS FOR MAXES...GIVEN THE EXPECTATION FOR A PERIOD OF STRONG
DOWNSLOPING WINDS AND SOME SUN...WE ARE FORECASTING RECORD MAXES FOR
MANY AREAS...SOME OF WHICH ARE LISTED BELOW WITHIN THE CLIMATE
SECTION. THESE MAXES ARE IN LINE WITH THE WARMER MET MOS...WITH
LOWER/MID 60S QUITE POSSIBLE ACROSS VALLEY REGIONS...ALBEIT A BIT
COOLER ACROSS NORTHERN PORTIONS OF THE HUDSON RIVER VALLEY AND LAKE
GEORGE/SARATOGA REGION WHERE A LOW LEVEL NNE AGEOSTROPHIC FLOW MAY
ALLOW COOLER AIR...AND LOW CLOUDS TO LINGER A BIT LONGER INTO THE
LATE MORNING HOURS. TEMPERATURES WILL THEN FALL DURING THE
AFTERNOON...THROUGH THE 50S AND INTO THE 40S BY EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
TONIGHT...DESPITE FAVORABLE OROGRAPHICAL EFFECTS ACROSS THE
DACKS...OVERALL LAKE EFFECT SNOWBAND POTENTIAL LOOKS LOW...GIVEN
RAPIDLY LOWERING SUBSIDENCE INVERSION...HIGH SHEAR...AND WITH CLOUD
TOP TEMPS FORECAST TO REMAIN WARMER THAN -10 C. THIS SHOULD FAVOR
MORE OF A GRAINY TEXTURE TO THE SNOW...RATHER THAN
DENDRITIC...LIMITING ACCUM POTENTIAL. WE THEREFORE EXPECT ONLY LIGHT
ACCUMS...GENERALLY AN INCH OR LESS OVERNIGHT ACROSS CENTRAL AND
NORTHERN HERKIMER CO AND PERHAPS WEST CENTRAL HAMILTON CO...WITH A
COATING POSSIBLE INTO THE WESTERN MOHAWK VALLEY. AS SUBSIDENCE
INVERSION LOWERS RAPIDLY...WE EXPECT LAKE MOISTURE TO BECOME TRAPPED
UNDERNEATH FROM THE CAPITAL REGION N AND NE. SO...IN THESE
AREAS...WILL INDICATE MOSTLY CLOUDY SKIES OVERNIGHT...ALONG WITH
MILDER OVERNIGHT MINS...GENERALLY IN THE LOWER/MID 30S.
FRI/FRI NT...WE EXPECT SNOW SHOWERS TO PERSIST ACROSS THE SW DACKS
IN THE MORNING...WITH ANY BAND GRADUALLY LIFTING NORTH IN THE
AFTERNOON IN RESPONSE TO BACKING LOW LEVEL WINDS. ELSEWHERE...WE
EXPECT PARTLY TO MOSTLY SUNNY SKIES...ALTHOUGH CLOUDS MAY LINGER FOR
AREAS IMMEDIATELY N AND NW OF THE CAPITAL REGION THROUGH LATE
MORNING. WE EXPECT MIXING TO AROUND 850 MB...YIELDING MAXES IN THE
MID/UPPER 40S WITHIN THE VALLEYS...AND UPPER 30S/LOWER 40S FOR
HIGHER ELEVATIONS. FOR FRI NT...SOME SNOW SHOWERS ARE STILL POSSIBLE
FOR THE SW DACKS...WITH GENERALLY DRY CONDITIONS ELSEWHERE. MINS
SHOULD BE COLDER THAN FRI AM...GENERALLY IN THE MID/UPPER 20S...WITH
UPPER TEENS TO LOWER 20S POSSIBLE ACROSS PORTIONS OF THE NORTH
COUNTRY.
SAT...ALL EYES WILL BE ON SOUTHERN STREAM SHORTWAVE TRAVERSING THE
TN VALLEY REGION AND HEADING ENE. THE GFS KEEPS MOST PRECIP S OF
REGION...WHILE THE NAM/UKMET ALLOW SOME LIGHT PRECIP TO REACH FAR
SOUTHERN AREAS. AT THIS TIME...WILL INDICATE SLIGHT CHC TO LOW CHC
POPS FOR EXTREME SOUTHERN AREAS...AND CHC POPS FOR LAKE EFFECT
ACROSS FAR NW AREAS. P-TYPE WOULD FAVOR SNOW GIVEN DEEP COLD LAYER.
AND...GIVEN HISTORY OF DEEP CONVECTION ASSOCIATED WITH GULF COAST
LOWS...IT IS POSSIBLE THAT SYSTEM COULD TREND FURTHER N/W WITH
FUTURE MODEL RUNS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WHILE MOST GLOBAL MODEL GUIDANCE SUGGESTS THE NEXT COASTAL WAVE WILL
BE FAR ENOUGH OFFSHORE WITH ASSOCIATED SHORT WAVE ALSO TRACKING
OFFSHORE SATURDAY EVENING ACROSS THE MID ATLANTIC...INTERESTING THAT
SEVERAL OF THE GFS ENSEMBLE AND SREF MEMBERS DO SUGGEST THIS WAVE
MIGHT TRACK A LITTLE FURTHER WEST. THIS COULD POSE AN ISSUE WITH AN
ACCUMULATING SNOW EVENT FROM THE CAPITAL DISTRICT AND POINTS SOUTH
AND EAST AS BAROCLINIC ZONE WILL BE NEARBY. WE WILL RAISE POPS
SLIGHTLY AT THIS TIME AND CONTINUE TO MONITOR TRENDS. THIS IS IN
CLOSE COLLABORATION WITH NEIGHBORING OFFICES AS WELL.
IN THE WAKE OF THIS COASTAL SYSTEM...A NARROW WEDGE OF HIGH PRESSURE
CRESTS OVER THE REGION AS 850MB TEMPS DROP BACK TO AROUND -10C.
THIS WILL LIKELY BRING SOME LAKE EFFECT ACTIVITY BUT A COUPLE OF
QUESTIONS REMAIN. IF THIS AFOREMENTIONED WAVE IS A LITTLE
CLOSER...THEN IN ITS WAKE THE SUBSIDENCE WILL BE A BIT MORE
PRONOUNCED WHICH WILL LEAD TOWARD HIGHER SURFACE PRESSURES. IN
ADDITION...UPSTREAM SHORT WAVE ROUNDING THE BASE OF THE HUDSON
BAY/GREAT LAKE UPPER LOW REMAINS IN QUESTION WITH RESPECT TO
INTENSITY AND ORIENTATION. AT THIS POINT...PREFER TO KEEP POPS LOW
UNTIL THESE FEATURES BECOME MORE DEFINED.
THEN A WEAK WARM ADVECTION PATTERN EVOLVES FOR EARLY NEXT WEEK WITH
AN INCREASE IN CLOUD COVER AND PERHAPS A LITTLE LIGHT PRECIP EVENT.
THEN ATTENTION QUICKLY SHIFTS UPSTREAM AS POTENT SHORT WAVE
CURRENTLY SITUATED OVER THE BERING STRAITS ATTEMPTS TO SUCCESSFUL
INTERACT WITH VORTEX OVER THE WESTERN ARCTIC CIRCLE /PER THE PVU1.5
TRACE/. GENERALLY SPEAKING...THE GLOBAL MODELS ARE IN GENERAL
AGREEMENT WITH THE PATTERN EVOLUTION FOR NORTH AMERICA WITH A DEEP
AND COLD LONG WAVE TROUGH DEVELOPING. THIS TOO AGREES WITH MJO
FORECAST PHASE 7 WHICH FAVORS NOT ONLY COLDER PATTERN
DEVELOPING...BUT EAST COAST CYCLOGENESIS FOR MID WEEK. THE GFS IS
WARMER WITH A WINTRY MIX TO MAINLY RAIN AND THE THE ECMWF IS QUITE
COLDER WITH MAINLY SNOW. AT THIS POINT...WE WILL RAISE POPS A BIT
AND GO WITH A WINTRY MIXTURE. CONFIDENCE NOT HIGH ENOUGH TO MENTION
IN THE HWO BUT SOMETHING TO WATCH.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LINE OF CONVECTION WAS QUICKLY PROGRESSING ACROSS THE HUDSON RIVER
VALLEY WITH MODERATE TO HEAVY RAINFALL AND WIND GUSTS 30-40
KTS...WITH LLWS CRITERIA. MVFR/IFR CIGS AND VIS WILL BE COMMON THIS
EARLY THURSDAY MORNING TO BE FOLLOWED BY IMPROVEMENTS THROUGH THE
MID MORNING HOURS. WITH THE IMPROVEMENT WILL COME ABOUT AN INCREASE
IN SURFACE WINDS AS GUSTS ARE EXPECTED TO BE WELL INTO THE UPPER
20KT RANGE. CLOUDS WILL VARY FROM VFR TO SCT-BKN MVFR FOR THE
REMAINDER OF THE DAY AS STORM LIFTS NORTHEAST AWAY FROM THE REGION.
OUTLOOK...
FRI-SUN...VFR...NO SIG WX.
MON...VFR TO MVFR...SLGT CHC -SN.
&&
.HYDROLOGY...
TOTAL QPF FROM THIS STORM SYSTEM SHOULD RANGE FROM 0.50 TO 1.25
INCHES INTO THIS MORNING. THIS RAINFALL WILL CAUSE SIGNIFICANT
RISES ON AREA RIVERS...BUT WILL LIKELY REMAIN WITHIN THEIR BANKS.
SOME DRAINAGE PROBLEMS ON ROADS AND PARKING AREAS ARE POSSIBLE GIVEN
LEAVES CLOGGING SOME STORM DRAINS. AN EMBEDDED THUNDERSTORM OR TWO
WILL REMAIN POSSIBLE THIS MORNING WHICH COULD LOCALLY ENHANCE
RAINFALL AMOUNTS.
SOME LIGHT LAKE EFFECT SNOW MAY OCCUR THURSDAY NIGHT AND FRIDAY
ACROSS PORTIONS OF THE WESTERN ADIRONDACKS IN THE WAKE OF THE STORM
AS COLDER AIR MOVES BACK IN...BUT OTHERWISE IT WILL BE DRY ACROSS
MUCH OF THE AREA. MAINLY DRY WEATHER IS EXPECTED THE REMAINDER OF
THE PERIOD INTO THE WEEKEND...WITH JUST A CHANCE OF SOME LIGHT SNOW
FROM THE FRINGES OF AN OCEAN LOW MOVING WELL OFF SHORE.
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.
&&
.CLIMATE...
LOCATION RECORD YEAR FORECAST HIGH
ALBANY 58 1998 61
POUGHKEEPSIE 58 1962 64
GLENS FALLS 55 1998 59
PITTSFIELD 57 1950 61
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...BGM
AVIATION...BGM
HYDROLOGY...SND/KL
CLIMATE...KL/JPV
WWW.WEATHER.GOV/ALBANY
