February 10, 2012 Forecast Discussion

000
FXUS61 KALY 102203
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
503 PM EST FRI FEB 10 2012

.SYNOPSIS…
A COLD FRONT WILL SLOWLY APPROACH FROM THE NORTHWEST
LATE TONIGHT AND SATURDAY…WHILE A DEVELOPING LOW PRESSURE SYSTEM
TRACKS NORTHEASTWARD OFF THE MID ATLANTIC COAST. THE INTERACTION
BETWEEN THESE TWO SYSTEMS WILL ALLOW FOR SNOW SHOWERS TO DEVELOP
LATE TONIGHT INTO SATURDAY MORNING…WITH A PERIOD OF STEADIER LIGHT
SNOW POSSIBLE ACROSS SOUTHEAST AREAS. MUCH COLDER AIR WILL SWEEP
INTO THE REGION BEHIND THE FRONT FOR SATURDAY NIGHT AND
SUNDAY…ALONG WITH SCATTERED SNOW SHOWERS AND POSSIBLE LAKE EFFECT
SNOW SQUALLS.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/…
AS OF 450 PM EST…HIGH AND MID LEVEL CLOUDS HAVE OVERSPREAD THE
REGION…AS MID AND UPPER LEVEL MOISTURE FROM A SHORTWAVE ACROSS
THE LOWER MISSISSIPPI VALLEY ADVECTS NNE AHEAD OF AMPLIFYING UPPER
LEVEL NORTHERN STREAM TROUGH. THIS SOUTHERN STREAM WAVE IS
EXPECTED TO CONTINUE TRACKING ENE…EVENTUALLY ALLOWING FOR A SFC
LOW TO DEVELOP OFF THE NORTHERN MID ATLANTIC COAST AND HEAD ENE.
IN THE MEANTIME…AN ARCTIC FRONTAL BOUNDARY WILL CONTINUE SLOWLY
ADVANCING S AND E ACROSS THE GREAT LAKES. AS THE SFC LOW TRACKS
WELL SOUTH OF THE REGION…THE ARCTIC BOUNDARY WILL EVENTUALLY
ACCELERATE S/E LATER TONIGHT. THE INTERACTION BETWEEN THE
INCREASING MOISTURE AND LIFT AHEAD OF THE AMPLIFYING TROUGH
APPROACHING FROM THE W SHOULD ALLOW FOR AREAS OF LIGHT SNOW OR
SNOW SHOWERS TO DEVELOP FROM SW TO NE ACROSS THE REGION AFTER
MIDNIGHT…AND MORE LIKELY TOWARD DAYBREAK. SOMEWHAT BETTER MID
LEVEL FRONTOGENETICAL FORCING WILL TRANSLATE ACROSS SOUTHERN AREAS
TOWARD DAYBREAK…ALLOWING THE A PERIOD OF STEADIER…LIGHT SNOW
TO DEVELOP FROM THE MID HUDSON VALLEY INTO NW CT. IN THESE
AREAS…ACCUMS OF UP TO AN INCH COULD OCCUR BY DAYBREAK.
ELSEWHERE…EXPECT ANY ACCUMS TO RANGE FROM A DUSTING…TO LESS
THAN ONE INCH BY SUNRISE.

AS FOR TEMPS…SINCE MOST OF OUR REGION WILL REMAIN AHEAD OF THE
COLD FRONT…AND THE FACT THAT CLOUDS WILL BE RAPIDLY
THICKENING…IT APPEARS THAT THE MAIN COOLING POTENTIAL OVERNIGHT
WILL BE MAINLY FROM EVAPORATIONAL COOLING. WE HAVE THEREFORE
INDICATED MIN TEMPS A BIT ABOVE BOTH THE MAV AND MET MOS…WITH
GENERALLY 25-30 WITHIN THE HUDSON RIVER VALLEY FROM ALBANY
SOUTH…AND LOWER/MID 20S NORTH…AND ACROSS HIGHER ELEVATIONS
WITHIN WESTERN NEW ENGLAND. SLIGHTLY COLDER MINS WILL OCCUR ACROSS
THE WESTERN ADIRONDACKS…AS THE FRONT PASSES THROUGH BEFORE
DAYBREAK…ALLOWING FOR MINS TO FALL INTO THE MID/UPPER TEENS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/…
SATURDAY…THE INTERACTION BETWEEN THE INCOMING FRONT…AND
MOISTURE TRANSLATING NORTH FROM THE DEVELOPING SFC LOW WILL BE
MAXIMIZED DURING THE MORNING HOURS. THIS SHOULD PRODUCE WIDESPREAD
SNOW SHOWERS…ALONG WITH A PERIOD OF STEADY LIGHT SNOW ACROSS THE
MID HUDSON VALLEY/SE CATSKILLS…NORTHEAST ACROSS THE SOUTHERN
TACONICS AND BERKSHIRES. IN THIS REGION…EXPECT 1-3 INCHES OF
TOTAL SNOWFALL…EXCEPT FOR PERHAPS 2-4 INCHES ACROSS HIGHER
ELEVATIONS ACROSS NE LITCHFIELD CO CT. ELSEWHERE…EXPECT ACCUMS
TO REACH UP TO ONE INCH FROM THE SNOW SHOWERS. AS THE MAIN FORCING
PASSES E OF THE REGION IN THE AFTERNOON…EXPECT THE SNOW SHOWERS
TO DIMINISH IN AREAL COVERAGE…WITH THE POSSIBLE EXCEPTION OF A
BRIEF BURST OF SNOW WITH THE PASSAGE OF THE WEAKENING ARCTIC
BOUNDARY. SKIES SHOULD REMAIN MOSTLY CLOUDY INTO THE AFTERNOON
HOURS…ALTHOUGH SOME BREAKS MAY DEVELOP JUST PRIOR TO SUNSET AS
SLIGHTLY DRIER AIR FILTERS SOUTHEAST. FOR MAX TEMPS…TRICKY
CALL…AS THE MET MOS INDICATES MAXES REACHING THE MID OR UPPER 30S
WITHIN THE VALLEY REGIONS…WHILE THE MAV MOS REMAINS
COLDER…GENERALLY ONLY REACHING THE LOWER/MID 30S. WE HAVE SIDED
WITH THE COLDER MAV MOS FOR MAXES…AS COLDER AIR SHOULD FILTER
SOUTHWARD FAIRLY RAPIDLY DURING THE AFTERNOON…ESP DOWN THE
HUDSON RIVER VALLEY. HOWEVER…SHOULD LESS SNOWFALL OCCUR ACROSS
THE REGION THAN CURRENTLY EXPECTED…SLIGHTLY WARMER MAXES CLOSER
TO THE MET MOS CAN NOT BE RULED OUT.

SAT NT-SUN NT…INITIALLY…SAT NT SHOULD HAVE RELATIVELY FAIR
CONDITIONS…WITH PERHAPS JUST A FEW FLURRIES…AND PERHAPS SOME
BREAKS IN THE CLOUDS. HOWEVER…ANOTHER UPPER LEVEL SHORTWAVE AND
ATTENDANT SFC TROUGH WILL APPROACH FROM THE NW LATE AT NIGHT…AND
PASS THROUGH DURING SUNDAY. THIS SHOULD ALLOW SNOW SHOWERS TO
INCREASE IN AREAL COVERAGE ONCE AGAIN LATE SAT NT. THEN ON
SUNDAY…FAIRLY WIDESPREAD SNOW SHOWERS AND FLURRIES ARE EXPECTED.
IN ADDITION…THE POTENTIAL FOR LAKE EFFECT OR ENHANCED SNOWBANDS
LOOKS TO BE SOMEWHAT HIGH BY SUN AFTERNOON AND EVENING…AS WINDS
SHIFT INTO A GENERAL 300-310 DIRECTION…WITH AT LEAST
CONDITIONAL INSTABILITY…AND REDUCED WIND SHEAR…IN ADDITION TO
ADDED LOW LEVEL CONVERGENCE FROM THE AFOREMENTIONED SFC TROUGH
PASSING SOUTHWARD. THIS OVERALL PATTERN MAY ALLOW FOR ENHANCED
SNOW SHOWERS OR BANDS TO DEVELOP ACROSS THE WESTERN MOHAWK
VALLEY…BEFORE MIGRATING SLIGHTLY SOUTHWARD INTO THE SCHOHARIE
VALLEY…AND PERHAPS PORTIONS OF THE CAPITAL DISTRICT LATE SUN
AFTERNOON AND EARLY SUN NT. THIS COULD CREATE LOCALIZED ACCUMS OF
1-3 INCHES…AND POSSIBLY HIGHER…EVEN APPROACHING ADVISORY
LEVELS ACROSS SW HERKIMER CO…AND SCHOHARIE CO DURING THIS TIME
FRAME. WILL HIGHLIGHT THIS POTENTIAL IN THE HWOALY.
ESSENTIALLY…IT IS QUITE CONCEIVABLE THAT SOME AREAS RECEIVE MORE
SNOWFALL DURING THIS PERIOD THAN WITH SATURDAY/S SNOWFALL. FOR
TEMPS…GENERALLY WENT CLOSER TO THE SLIGHTLY WARMER MET MOS IN
MOST AREAS FOR SAT NT…EXCEPT ACROSS THE MID HUDSON VALLEY AND NW
CT WHERE SOME SNOWPACK MAY ALLOW FOR COLDER MINS…A BLEND OF
MAV/MET MOS FOR SUN…AND CLOSER TO THE COLDER MAV MOS FOR SUN NT.
AT THIS TIME…FORECAST WIND CHILL VALUES REMAIN UNDER ADVISORY
LEVELS…ALTHOUGH COULD GET CLOSE ACROSS PORTIONS OF THE WESTERN
ADIRONDACKS. WILL ALSO ADDRESS THIS IN THE HWOALY.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/…
THE PATTERN OF NO MAJOR EVENTS CONTINUES. WEAK HIGH PRESSURE RULES
THE EARLY PART OF THE PERIOD WITH INCREASINGLY ABOVE NORMAL
TEMPERATURES THROUGH THURSDAY AS A MILD SOUTHERLY FLOW ENSUES FROM
THE OUTSET…REACHING A PEAK OF HIGHS IN THE 35 TO 45 DEGREE RANGE.
THE ONLY MILDLY INTERESTING POINT DURING THE EXTENDED IS THURSDAY
NIGHT…WITH WEAK DEEP SOUTH LOW PRESSURE EXPECTED TO TRACK
EXPEDITIOUSLY OFF THE CAROLINAS COAST THROUGH LATE FRIDAY.
MEANWHILE…A WEAK CLIPPER SYSTEM APPROACHES US FROM THE NORTHERN
GREAT LAKES AND BECOMES DIFFUSE. HAVE CHC POPS…ACROSS THE WESTERN
PORTIONS OF THE ADIRONDACKS AND MOHAWK VALLEY FOR MAINLY SNOW
SHOWERS…AND ACROSS THE EXTREME SOUTHERN AREA FOR MAINLY SYNOPTIC
LIGHT SNOW. ELSEWHERE…GOING WITH SLGT CHC. THIS IS NOT THE ONLY
CHC FOR PRECIP THOUGH. WEAK BOUNDARIES IN THE VICINITY WITHIN OUR
OVERALL WEAK PATTERN NECESSITATES THE INCLUSION OF AREAS OF CHC POPS
ANYWHERE FROM TUESDAY TO WEDNESDAY NIGHT…HOWEVER…QPFS WILL BE
QUITE MINIMAL.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/…
VFR CONDITIONS WILL CONTINUE THIS AFTN INTO THIS EVENING WITH LIGHT
WINDS. INCREASING AMOUNTS OF MID LEVEL ALTOSTRATUS AND HIGH LEVEL
CIRRUS WILL CONTINUE THROUGH THE AFTN HOURS…WITH SKIES BECOMING
OVC BY THIS EVENING.

AFTER MIDNIGHT…AN APPROACHING ARCTIC FRONTAL BOUNDARY MAY ALLOW
FOR SOME SCT -SHSN. AT THE SAME TIME…A DEVELOPING AREA OF LOW
PRESSURE OFF THE ATLANTIC COAST WILL TRY TO SPREAD SOME LIGHT SNOW
NORTHWARD INTO THE REGION. THERE MAY BE A PERIOD OF STEADY SNOWFALL
AFTER 09Z. WHILE IT SHOULD BE FAIRLY LIGHT…FLYING CONDITIONS WILL
DROP TO DUE TO VSBYS TO MVFR LEVELS. THERE IS A POSSIBLY THERE MAY
EVEN BE A PERIOD OF IFR CONDITIONS…MAINLY FOR KPOU. THIS STEADY
SNOW WILL CONTINUE FOR A FEW HOURS INTO SATURDAY MORNING. BY THE
LATE MORNING…ANY STEADY SNOWFALL WILL END…TAPERING TO JUST SCT
-SHSN/FLURRIES AS THE STORM PULLS AWAY AND THE ARCTIC BOUNDARY SINKS
SOUTH OF THE REGION. THIS SHOULD ALLOW FOR VSBYS TO RETURN TO VFR
LEVELS…ALTHOUGH SOME MVFR CIGS COULD CONTINUE FOR A FEW HOURS INTO
THE AFTN.

WINDS OVERNIGHT WILL BE LIGHT TO NEARLY CALM. TOWARDS SUNRISE…THEY
WILL BE OUT OF A NORTHEASTERLY DIRECTION AT LESS THAN 5
KTS…BECOMING NORTHWEST BY MID TO LATE MORNING AROUND 5 KTS.

OUTLOOK…
SUN…VFR-MVFR. CHC -SHSN AT KALB AND SLIGHT CHC KGFL AND KPOU.
SUN NT-MON NT…VFR. NO SIG WX.
TUE-WED…VFR/MVFR. SLIGHT CHC -SHRA/-SHSN.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED INTO NEXT WEEK. SOME GAGES WILL
CONTINUE TO BE IMPACTED BY ICE ACROSS NORTHERN PORTIONS OF THE
HYDROLOGIC SERVICE AREA.

COLDER AIR WILL BE USHERED IN THE REGION THIS WEEKEND AND LIGHT SNOW
IS EXPECTED. THE COLDER TEMPERATURES MAY ALLOW ADDITIONAL ICE
FORMATION TO OCCUR LATE SATURDAY INTO EARLY MONDAY…ESPECIALLY
ACROSS THE SOUTHERN ADIRONDACKS…AND AREAS NORTH OF THE MOHAWK
RIVER VALLEY. TEMPERATURES WILL GRADUALLY MODERATE NEXT WEEK.

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…KL
NEAR TERM…KL
SHORT TERM…KL
LONG TERM…ELH
AVIATION…FRUGIS
HYDROLOGY…KL/IAA

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