February 24, 2012 Forecast Discussion

000
FXUS61 KALY 241201
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
700 AM EST FRI FEB 24 2012

.SYNOPSIS…
A COMPLEX LOW PRESSURE SYSTEM WILL AFFECT THE REGION THROUGH TONIGHT
WITH SNOW AND RAIN. SOME LINGERING SNOW SHOWERS ALONG WITH WINDY
CONDITIONS WILL OCCUR IN THE WAKE OF THE STORM ON SATURDAY. FAIR AND
CHILLY CONDITIONS WILL RETURN FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 630 AM…INITIAL BAND OF HEAVY SNOW THAT WAS OVER THE SOUTHERN
PART OF THE FORECAST AREA EARLIER THIS MORNING HAS CONTINUED TO FALL
APART AS IT SHIFTS SLOWLY NORTH. VERY UNLIKELY THAT ANY AREA WHERE
ADVISORIES ARE IN EFFECT WILL GET ADVISORY LEVEL (4 INCHES OR MORE)
SNOW THIS MORNING. IN FACT…DRY SLOT MOVING INTO THE REGION WILL
RESULT IN MOST OF THE REGION ONLY HAVING CHANE POPS FOR MOST OF THE
REST OF THIS MORNING.

AFTER THAT…ANOTHER ROUND OF SIGNIFICANT PCPN MOVES IN LATER TODAY
AHEAD OF THE FRONTAL BOUNDARY ASSOCIATED WITH THE LOW MOVING THROUGH
THE EASTERN GREAT LAKES. THIS BAND OF PCPN MAY PRODUCE SOME
ACCUMULATING SNOW OVER THE ADIRONDACKS LATE THIS AFTERNOON AND EARLY
EVENING…SO HAVE LEFT THE ADVISORIES IN EFFECT THERE. ELSEWHERE IT
WILL BE TOO WARM FOR SNOW BY THEN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/…
AS STATED IN THE NEAR TERM DISCUSSION…ANOTHER ROUND OF SIGNIFICANT
PCPN WILL MOVE THROUGH THE REGION THIS EVENING AHEAD OF A FRONTAL
BOUNDARY. BY THAT TIME MOST AREAS WILL BE TOO WARM FOR SNOW
RAIN…BUT AREAS FROM THE ADIRONDACKS TO LAKE GEORGE AND SOUTHERN
VERMONT COULD STILL BE COLD ENOUGH TO GET SOME SNOW FROM THE NEXT
ROUND OF PCPN…SO THE WINTER WEATHER ADVISORIES REMAIN IN EFFECT
THERE. BEHIND THE FRONTAL BOUNDARY STRONG WESTERLY WINDS AND THE
APPROACH OF THE UPPER LEVEL TROF ASSOCIATED WITH THE SURFACE LOW
WILL PRODUCE A PERIOD OF SCATTERED TO WIDESPREAD SNOW SHOWERS ACROSS
THE REGION DUE TO A COMBINATION OF UPSLOPE AND LAKE ENHANCED SNOW
ACROSS THE REGION….WITH THIS PATTERN PERSISTING WELL INTO SATURDAY
NIGHT…BUT GRADUALLY DIMINISHING WITH TIME.

BEHIND THE SURFACE LOW EXPECT STRONG WEST TO NORTHWEST WINDS LATE
FRIDAY NIGHT THROUGH SATURDAY AND A WIND ADVISORY HAS BEEN ISSUED.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY WITH TRANQUIL BUT COLD
WEATHER.

LOWS FRIDAY NIGHT WILL BE BETWEEN 20 AND 30 WITH WIND GUSTS UP TO 50
MPH POSSIBLE BY LATE AT NIGHT. HIGHS SATURDAY WILL BE IN THE UPPER
20S TO LOWER 40S WITH WIND GUSTS UP TO 50 MPH POSSIBLE THROUGHOUT
THE DAY. WINDS WILL DECREASE SOMEWHAT SATURDAY NIGHT…BUT STILL
BLOW AT 10 TO 20 MPH WITH GUSTS TO 30 MPH. LIGHTER WINDS FINALLY
SUNDAY WITH GUSTS UP TO AROUND 20 MPH…BUT DECREASING EVEN FURTHER
BY LATE IN THE DAY. HIGHS WILL BE IN THE MID 20S TO THE 30S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/…
DETERMINISTIC…BOTH 00Z EURO AND 00Z GFS SHOW WEAK UPPER IMPULSE
MOVING NORTH OF THE AREA ON MONDAY. SOME TIMING DIFFERENCES BUT
OVERALL IMPACT WILL BE FOR CLOUDS/CHANCE POPS OVER NORTHERN THIRD OF
AREA. REST OF AREA SHOULD REMAIN PARTLY SUNNY AND DRY. AFTER
IMPULSE PASSES BY A WEAK COLD FRONT CROSSES AREA MONDAY NIGHT. COLD
ADVECTION MAY LEAD TO SOME SCATTERED LAKE EFFECT SNOW SHOWERS SO
SLT/CHC POPS NORTHWEST EARLY TUESDAY BUT RIDGING SHOULD LEAD TO
MAINLY FAIR WEATHER ACROSS AREA. BY WEDNESDAY ANOTHER STORM SYSTEM
MOVES INTO GREAT LAKES REGION AND UP SAINT LAWRENCE AND LIKE PRESENT
STORM…THIS ONE BRINGS WINTRY MIX CHANGING TO RAIN AND BACK TO SNOW
DOWNWIND OF LAKE ONTARIO AND OVER HIGHER TERRAIN. EURO A LITTLE
SLOWER BUT BY LATE THURSDAY ALL BUT FAR NORTHWEST SHOULD BE DRY WITH
LINGERING LAKE EFFECT AND UPSLOPE SNOW SHOWERS. BOTH MODELS SHOW
RIDGING BUILDING INTO THE AREA ON FRIDAY WITH FAIR WEATHER.

PROBABILISTIC…00Z GEFS ENSEMBLES SHOW HIGHEST PROBABILITY OF
PRECIP ON WEDNESDAY INTO THURSDAY. EXTENDED STATISTICAL GUIDANCE
SHOWS TEMPS AVERAGING ABOVE NORMAL ALTHOUGH SATURDAY THROUGH MONDAY
WILL BE NEAR NORMAL.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/…
LOW PRESSURE OVER OHIO THIS MORNING WILL MOVE UP THE SAINT LAWRENCE
VALLEY TONIGHT. A WARM FRONT WILL BRING PERIODS OF SNOW AND RAIN TO
KALB AND KGFL WHILE KPOU WILL SEE PERIODS OF RAIN. MVFR CONDITIONS
ARE EXPECTED AT THE TAF SITES MOST OF TODAY INTO THIS EVENING BEFORE
A COLD FRONT SWEEPS THROUGH. BEHIND THE FRONT SOME LIGHT SNOW OR
SNOW SHOWERS ARE POSSIBLE OVERNIGHT AT KGFL AND KALB WITH MVFR. VFR
BEHIND FRONT AT KPOU.

WINDS WILL BE EAST NORTHEAST AT 6 KTS OR LESS FRIDAY MORNING AND
EAST TO SOUTHEAST AROUND 10 KTS OR LESS FRIDAY AFTERNOON. WINDS WILL
SWITCH TO SOUTHWEST TO WEST NEAR MIDNIGHT AND BECOME GUSTY. WINDS
SATURDAY WEST TO NORTHWEST 15 TO 25 KTS WITH OCCASIONAL GUST TO 40KT.

OUTLOOK….
LATE FRI NGT…VFR/MVFR…CHC -SHSN. BECOMING WINDY.
SAT…VFR…SLIGHT CHC -SHSN. WINDY.
SAT NIGHT-SUN…VFR…DECREASING WINDS.
MON…VFR SLIGHT CHC -SHRA/-SHSN.
TUE…VFR.

&&

.HYDROLOGY…
SOME MODERATE RIVER RISES ARE POSSIBLE OVER THE SOUTHERN THIRD OF
OUR AREA TONIGHT AS RUNOFF FROM MELTING SNOW COMBINES WITH RUNOFF
FROM SOME HEAVIER DOWNPOURS AHEAD OF A COLD FRONT. SOME PONDING OF
WATER IN LOW LYING AND POOR DRAINAGE AREAS MAY SLOW THE EVENING
COMMUTE. NO LARGER RIVER FLOODING IS EXPECTED DURING THE NEXT 5 DAYS.

SOME GAGES ARE STILL BEING IMPACTED BY ICE ACROSS NORTHERN PORTIONS
OF THE HYDROLOGIC SERVICE AREA. PERSISTENT COLD TEMPERATURES THIS
WEEKEND MAY ALLOW ADDITIONAL ICE FORMATION TO OCCUR LATE SATURDAY
INTO EARLY MONDAY IN BASINS NORTH OF THE MOHAWK RIVER VALLEY.

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 FROM 1 AM TO 7 PM EST SATURDAY FOR CTZ001-013.
NY…WIND ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
NYZ032-033-042-082.
MA…WIND ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR MAZ001-025.
VT…WIND ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR VTZ013>015.

&&

$$
SYNOPSIS…GJM
NEAR TERM…GJM
SHORT TERM…GJM
LONG TERM…SND
AVIATION…SND
HYDROLOGY…SND

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