FXUS61 KALY 281909
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
209 PM EST SAT NOV 28 2009
.SYNOPSIS...
A VERY STRONG LOW PRESSURE SYSTEM NEAR NOVA SCOTIA WILL
MOVE NORTHEAST THROUGH THE CANADIAN MARITIMES THIS AFTERNOON. THE
STRONG GUSTY WINDS WILL DIMINISH THIS EVENING. HIGH PRESSURE WILL
BUILD INTO THE AREA FROM THE SOUTHWEST LATER TONIGHT INTO EARLY
SUNDAY...BEFORE ANOTHER STORM SYSTEM APPROACHES OUR REGION FROM THE
GREAT LAKES SUNDAY EVENING BRINGING MORE UNSETTLED WEATHER SUNDAY
NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 200 PM EST...QUICK EARLY AFTERNOON UPDATE TO CANCEL THE HIGH WIND
WARNING AND WIND ADVISORY FOR THE REGION. THE GUSTS HAVE BEEN
DIMINISHING BELOW 46 MPH BASED ON THE OBSERVATIONS THE PAST FEW
HOURS. A ROGUE GUST OR TWO IS STILL POSSIBLE...BUT THE SFC
PRESSURE GRADIENT BTWN THE INTENSE SFC CYCLONE NEAR NOVA
SCOTIA...AND HIGH PRESSURE OVER THE SOUTHEAST WILL CONTINUE TO
WEAKEN. SKY COVER WAS ALSO ADJUSTED BASED ON THE VISIBLE SATELLITE
PICTURE TOO.
PREVIOUS NEAR TERM...
AS OF 930 AM EST...THE RUC13 HAS THE OCCLUDED LOW /978 HPA/
CENTERED BTWN NOVA SCOTIA AND NEW BRUNSWICK WITH BLUSTERY NW WINDS
CONTINUING OVER THE FCST AREA. THE WIND HEADLINES WILL REMAIN
INTACT. KALB CONTINUES TO RECORD WIND GUSTS OF 40-45 KTS DUE TO
STRONG MOMENTUM TRANSFER FROM 2-3.5 KFT AGL /40-50 KTS/.
WE CUT BACK THE POPS TO JUST SLIGHT CHANCE AND LOW CHANCE VALUES WEST
OF THE HUDSON RIVER VALLEY...AND NO POPS EAST. THE BOUNDARY LAYER
IS DRYING OUT...AND THE LAKE FETCH OFF LAKE ONTARIO IS MINIMAL.
THE RADAR COVERAGE AREA HAS SHRUNK SIGNIFICANTLY IN THE PAST FEW
HOURS TOO. WE ALSO INCREASED THE SUNSHINE POTENTIAL IN THE HUDSON
RIVER VALLEY EAST DUE TO THE DOWNSLOPING OFF THE ERN
CATSKILLS...AND ADIRONDACKS. WE WILL USE PARTLY SUNNY EAST...AND
PARTLY TO MOSTLY CLOUDY WEST. TEMPS TRENDS WERE ALSO REDONE BASED
ON OBS.
PREVIOUS NEAR TERM FCST DISCUSSION BELOW... THE STRONGEST WINDS
HAVE OCCURRED IN MOST PLACES SINCE 06Z AND EXPECT THAT THERE STILL
MAY BE A FEW HIGHER GUSTS AS WINDS MAX OUT ACROSS BULK OF FA BTWN
NOW AND 15Z THIS MORNING BASED ON PRESSURE GRADIENT...0-30 MB AGL
WINDS WHICH STILL HAVE NUMEROUS FLAGS ORIENTED FROM SRN VT AND
BERKS BACK WEST INTO THE ERN CATSKILLS AT 12Z...AND ISALLOBARIC
COUPLET AT 12Z OF +5 TO -10 ON THE GFS AND +6 TO -8 ON THE NAM.
THE LOW BECOMES VERTICALLY STACKED AS IT DRIFTS INTO THE CANADIAN
MARITIMES LATER THIS MORNING INTO EARLY THIS AFTERNOON AND THE
PRESSURE GRADIENT SHOULD START TO WEAKEN AFTER 18Z. THUS WIND
ADVISORY AND HIGH WIND WARNING WILL BE LEFT IN TACT WITH NO CHANGE
TO WIND FIELDS FOR THE NEAR TERM. FOR INFORMATION ON WIND GUSTS
REFER TO ALBPNSALY AND FOR WIND DAMAGE REPORTS REFER TO ALBLSRALY.
AS FOR PCPN SHIELD IT HAS STARTED TO SHRINK IN COVERAGE AND WEAKEN
IN INTENSITY THE LAST COUPLE OF HOURS AND LITTLE ADDITIONAL
ACCUMULATION IS EXPECTED AT THIS POINT. HOWEVER...THE HIGHER
ELEVATIONS OF THE BERKSHIRES AND SOUTHERN GREEN MOUNTAINS PICKED
UP SEVERAL INCHES OF SNOW FROM FRIDAY EVENING THROUGH THE
OVERNIGHT PERIOD WHILE ELEVATIONS BELOW 1000 FEET REMAINED ALL
RAIN. PLEASE REFER TO ALBPNSALY FOR THE LATEST SNOWFALL
ACCUMULATIONS. FOR THIS AFTERNOON EXPECT SOME SUBSIDENCE/DOWN
SLOPING WHICH WILL ACTUALLY RESULT IN SOME BREAKS OF SUN AND ANY
LINGERING PCPN WHICH MAY HAVE SOME LAKE ENHANCEMENT WOULD BE
CONFINED TO FAR WESTERN PORTION OF FA. HIGHS WILL BE IN THE UPPER
30S TO UPPER 40S IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
FOR TONIGHT...ANY LINGERING SNOW SHOWERS EXPECTED TO BE CONFINED
TO THE WESTERN THIRD OF FA THIS EVENING WITH THE SNOW ENDING LAST
ACROSS THE WESTERN ADIRONDACKS WHERE A LITTLE LAKE ENHANCEMENT IS
POSSIBLE. FOR NOW WILL JUST GO WITH CHANCE POPS. LOWS TONIGHT
EXPECTED TO BE IN THE MID 20S TO LOWER 30S.
SUNDAY...LOOKS DRY AS HIGH PRESSURE BUILDS INTO FA WITH HIGHS IN
THE UPPER 30S TO LOWER 50S AND MUCH LESS WIND. CLOUDS WILL
INCREASE AGAIN ESPECIALLY DURING THE AFTERNOON AHEAD OF THE NEXT
SHORT WAVE.
ON SUNDAY NIGHT AND MONDAY...CLIPPER SYSTEM MOVING THROUGH THE
EASTERN GREAT LAKES SUNDAY EVENING WILL TRACK NORTHEAST UP THE
SAINT LAWRENCE RIVER VALLEY LATE SUNDAY NIGHT INTO MONDAY WHICH
WILL ONCE AGAIN BRING MIXED PCPN TO OUR REGION ALTHOUGH ANY LIGHT
SNOW SHOULD BE CONFINED MAINLY TO THE WESTERN ADIRONDACKS WHERE
AROUND AN INCH OF ACCUMULATION IS POSSIBLE BEFORE CHANGING OVER
TO MAINLY RAIN FOR A SHORT TIME ON MONDAY BEFORE COLDER AIR FUNNELS
BACK INTO THE REGION. MOST OTHER AREAS WILL HAVE RAIN WITH MAINLY
LIGHT QPF AMOUNTS IN THE QUARTER TO THIRD OF AN INCH RANGE.
EXPECT LOWS SUNDAY NIGHT IN THE UPPER 20S TO UPPER 30S WITH HIGHS
ON MONDAY IN THE UPPER 30S TO UPPER 40S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE GRADUALLY BUILDS IN FROM THE TN VALLEY MONDAY NIGHT.
THE WEST TO NORTHWEST FLOW...ALONG WITH RAPIDLY COOLING BOUNDARY
LAYER TEMPERATURES...SHOULD PROMOTE SOME LAKE EFFECT MOISTURE AND
CLOUDINESS. SOME LAKE EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE IN THE
ADIRONDACKS. LAKE EFFECT MOISTURE AND CLOUDS WILL PERIODICALLY
SPREAD ACROSS MUCH OF THE REGION THROUGH WEDNESDAY...ALONG WITH
ISOLATED/SCATTERED SNOW SHOWERS IN THE ADIRONDACKS. SOME FLAT UPPER
RIDGING BUILDS INTO THE REGION TUESDAY AND WEDNESDAY...SO BOUNDARY
LAYER TEMPERATURES WILL WARM GRADUALLY THROUGH WEDNESDAY.
LOWS MONDAY NIGHT IN THE 20S...SOME TEENS IN THE ADIRONDACKS. HIGHS
TUESDAY IN THE 40S...BUT 30S IN THE ADIRONDACKS...CATSKILLS AND
SOUTHERN GREEN MOUNTAINS. LOWS TUESDAY NIGHT WILL BE IN THE 20S TO
AROUND 30. HIGHS WEDNESDAY SHOULD BE IN THE MID TO UPPER 40S...SOME
UPPER 30S IN THE ADIRONDACKS AND AROUND 40 CATSKILLS AND SOUTHERN
GREEN MOUNTAINS.
THE NEXT SYSTEM APPROACHES FROM THE CENTRAL U.S. WEDNESDAY
NIGHT...WITH SOME HINTS AT A SOUTHERN STREAM PIECE OF UPPER ENERGY
TRACKING OUT OF THE NORTHERN GULF COAST STATES. THERE IS
CONSIDERABLE SPREAD IN LONG RANGE DETERMINISTIC GUIDANCE AND THE
ENSEMBLES AS TO THE TRACK OF THE UPPER AND SURFACE FEATURES...AND
POSITION OF THE ASSOCIATED BOUNDARY LAYER THERMAL GRADIENT. BASED
ON THE LONGWAVE PATTERN ACROSS NORTH AMERICA...EVEN IF THE SYSTEM
TRACKS ALONG THE COAST...BOUNDARY LAYER TEMPERATURES WITHIN THE
FRONTOGENETIC THERMAL GRADIENT NORTHWEST OF THE STORM MAY BE JUST A
LITTLE TOO WARM FOR SNOW IN MANY AREAS. AGAIN...LOTS OF UNCERTAINTY
IN TRACK OF SURFACE AND UPPER FEATURES...AND THERMAL PROFILES AND
RESULTANT PRECIPITATION TYPES.
SO DEPENDING ON ELEVATION AND SURFACE TEMPERATURES...SOME MIX LIKELY
IN HIGHER ELEVATIONS WEDNESDAY NIGHT AND THURSDAY MORNING...WITH
JUST SOME CHANCES FOR MIXING IN VALLEYS. TRANSITION TO RAIN DURING
THE DAY THURSDAY...ENDING AS SNOW SHOWERS MANY AREAS THURSDAY NIGHT.
LOWS WEDNESDAY NIGHT IN THE MID 20S TO AROUND 30 IN HIGHER
ELEVATIONS...LOWER TO MID 30S VALLEYS. HIGHS THURSDAY IN THE LOWER
TO MID 40S...LOWER TO MID 30S IN THE MOUNTAINS.
MEAN NORTHERN STREAM UPPER TROUGH AXIS NUDGES EVER SO SLIGHTLY
EAST...ALLOWING A LITTLE MORE COLD AIR TO GET INTO EASTERN NORTH
AMERICA TOWARD THE END OF THE WEEK. HIGH PRESSURE AGAIN BUILDS IN
FROM THE TN VALLEY THURSDAY NIGHT AND FRIDAY. WITH COOLING OF
BOUNDARY LAYER TEMPERATURES AND WEST TO NORTHWEST WINDS...LAKE
EFFECT CLOUDS AND ISOLATED/SCATTERED SNOW SHOWER ACTIVITY STARTS UP
AGAIN. LOWS THURSDAY NIGHT IN THE 20S...TEENS IN THE MOUNTAINS.
HIGHS FRIDAY IN THE 30S TO AROUND 40.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
WITH A STRONG PRESSURE GRADIENT BETWEEN A STORM OVER NOVA SCOTIA AND
HIGH PRESSURE OVER THE OHIO VALLEY...WINDS WILL CONTINUE TO BE GUSTY
THIS AFTN...ESP AT KALB...WHERE AIR FUNNELING DOWN THE MOHAWK VALLEY
WILL INCREASE THE WIND SPEEDS SOMEWHAT FOR KALB. GUSTS HERE WILL BE
HIGH AS 35-40 KTS THROUGH THE MID AFTN HOURS. BY LATE THIS
AFTN...THE LOSS OF DAYTIME HEATING WILL DECREASE MIXING AND THE
PRESSURE GRADIENT WILL BEGIN TO WEAKEN SOMEWHAT...DECREASING THE
WINDS SPEEDS ACROSS THE REGION. WINDS WILL EVENTUALLY FALL TO 5-10
KTS BY LATE TONIGHT...AND WILL BE LIGHT OUT OF THE SOUTH ON SUNDAY.
SKIES ARE VFR ACROSS THE HUDSON VALLEY TAF SITES AND WILL CONTINUE
TO BE SO THROUGH THE TAF PERIOD WITH JUST FEW-SCT CU THIS AFTN.
TONIGHT...SOME LAKE EFFECT MOISTURE WILL BRING A SCT-BKN DECK AT 3-4
KFT OVERNIGHT TO KALB/KGFL...BUT VFR SKIES WILL CONTINUE AND NO
PRECIP IS EXPECTED. SKIES WILL SCT OUT FOR SUNDAY WITH SOME JUST
PASSING CU AROUND 3 KFT AS HIGH PRESSURE BUILDS INTO THE REGION.
OUTLOOK...
SUN PM...VFR. NO SIG WX.
SUN NT-MON...MVFR/IFR. -RA/-SN.
TUE...VFR. SLGT CHC -SHRA/-SHSN.
WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
LIQUID EQUIVALENT PCPN AMOUNTS WITH THIS SYSTEM HAVE BEEN VERY
LIGHT WITH LESS THAN A TENTH OF AN INCH IN MANY AREAS EXCEPT
ACROSS THE TACONICS AND WESTERN NEW ENGLAND WHERE A HALF INCH TO
AROUND AN INCH FELL. RIVER RISES IN THESE AREAS ARE FORECAST TO
BE AROUND A FOOT. ELSEWHERE..RISES ARE FORECAST TO BE LESS THAN
HALF A FOOT. LITTLE ADDITIONAL QPF IS EXPECTED TODAY WITH MAINLY
DRY WEATHER TONIGHT AND SUNDAY BEFORE NEXT SYSTEM ARRIVES SUNDAY
NIGHT INTO MONDAY WITH GENERALLY A QUARTER TO A THIRD OF AN INCH
OF QPF.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...11/WASULA
NEAR TERM...11/WASULA
SHORT TERM...11
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...11
