February 26, 2012 Forecast Discussion

000
FXUS61 KALY 270052
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
752 PM EST SUN FEB 26 2012

.SYNOPSIS…
HIGH PRESSURE WILL BUILD INTO OUR REGION THROUGH TONIGHT…AND
THEN DRIFT OFFSHORE MONDAY. LOW PRESSURE WILL APPROACH FROM THE
GREAT LAKES MONDAY AND TRACK ALONG THE UNITED STATES…CANADA
BORDER AND NORTHERN NEW ENGLAND…TRACKING OFFSHORE TUESDAY
MORNING. HIGH PRESSURE WILL CONTROL THE REGIONAL WEATHER TUESDAY
AND TUESDAY NIGHT. THEN LOW PRESSURE IN THE GREAT LAKES WILL TRACK
THROUGH THE NORTHEASTERN UNITED STATES WEDNESDAY AND OFFSHORE NEW
ENGLAND WEDNESDAY NIGHT AND THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/…
- Changed Discussion -
LATEST SURFACE ANALYSIS SHOWS RIDGE OVER THE REGION CONTINUING TO
SHIFT EASTWARD. ALOFT…HAVE RIDGING WHICH WILL FLATTEN AS IT ALSO
SHIFTS EASTWARD. LOW PRESSURE WAS LOCATED OVER THE WESTERN GREAT
LAKES WITH A WARM FRONT EXTENDING EASTWARD INTO THE OHIO VALLEY.
WILL HAVE HIGH AND MID LEVEL WARM ADVECTION CLOUDS MOVING INTO THE
AREA MAINLY AFFECTING NORTHERN PORTION OVERNIGHT. THE FORECAST IS ON
TRACK…ONLY MADE SOME MINOR ADJUSTMENTS BASED ON OBSERVATIONAL
DATA. TEMPERATURES WILL BE SEASONAL AND WINDS LIGHT.
— End Changed Discussion -

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/…
WEAK NORTHERN STREAM UPPER IMPULSE WILL TRACK ACROSS NORTHERN
AREAS LATE MONDAY AFTERNOON AND EVENING. A QUICK SHOT OF STRONG
WARM ADVECTION AND STRONG BOUNDARY LAYER FLOW WILL RESULT IN
PERIODS OF MID AND HIGH CLOUDS. BUT INCREASING SUN ANGLE AND SOUTH
TO SOUTHWEST WINDS OCCASIONALLY BREEZY SHOULD AID IN MIXING. HIGHS
MONDAY WELL INTO THE 40S…SOME LOWER 50S SOUTHERN AREAS AND
UPPER 30S SOUTHERN ADIRONDACKS.

SOME SCATTERED TO ISOLATED RAIN/SNOW SHOWERS POSSIBLE MONDAY
EVENING…ESPECIALLY IN THE SOUTHERN ADIRONDACKS…LAKE GEORGE
SARATOGA REGION AND SOUTHERN GREEN MOUNTAINS. THEN THE COLD FRONT
WILL TRACK THROUGH WITH RELATIVELY STRONG COLD ADVECTION. WEST TO
NORTHWEST WINDS BEHIND THE FRONT SHOULD BE RELATIVELY BREEZY SO
COOLING MONDAY NIGHT MAY BE LIMITED WITH LOWS IN THE WARMER SIDE
OF GUIDANCE. LOWS MONDAY NIGHT IN THE MID 20S TO AROUND 30 WITH
SOME UPPER TEENS IN THE SOUTHERN ADIRONDACKS.

STRONG HIGH PRESSURE BUILDS IN FROM CANADA TUESDAY AND TUESDAY
NIGHT. BASED ON FORECASTED BOUNDARY LAYER TEMPERATURES AND MIXING
POTENTIAL…HIGHS TUESDAY IN THE UPPER 30S TO LOWER 40S…SOME
LOWER TO MID 30S IN THE HIGHER ELEVATIONS. THE LOW LEVEL RIDGING
SHOULD BE ABOUT DIRECTLY OVERHEAD TUESDAY EVENING AND BUILD EAST
LATE TUESDAY NIGHT. SOME DECENT RADIATIONAL COOLING CONDITIONS
SHOULD EXIST. SOME MID AND HIGH CLOUDS COULD SPREAD ACROSS THE
REGION AHEAD OF THE NEXT SYSTEM TOWARD DAYBREAK. LOWS IN THE LOWER
TO MID 20S…WITH TEENS IN THE SOUTHERN ADIRONDACKS AND SOUTHERN
GREEN MOUNTAINS. CLOUD COVER SPREADING EAST AND THICKENING TOWARD
DAYBREAK WEDNESDAY SHOULD KEEP MOST OF NOT THE ENTIRE REGION COLD
ENOUGH FOR SNOW TO BREAK OUT DURING THE DAY WEDNESDAY…PERHAPS
DURING THE MORNING…BUT THAT IS A DISCUSSION FOR THE LONG
TERM…WHICH FOLLOWS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/…
ACTIVE PATTERN EXPECTED FOR THE LONG TERM WITH UPPER LEVEL CLOSED
LOW OVER NORTH CENTRAL USA MOVING EASTWARD WILL BRING ASSOCIATED
CLOSED SFC LOW OVER THE SOUTHERN GREAT LAKES REGION AND A WARM
FRONT AHEAD OF IT INTO THE NE.

SFC HIGH PRESSURE JUST WEST OF NEWFOUNDLAND WILL HELP FILTER
COLDER AIR INTO THE FA BEFORE WAA OCCURS. THIS WILL ALSO HELP
KEEP AREAS IN THE NORTH COUNTRY AND ADK IN THE COLDER
AIR…KEEPING PRECIP AS SNOW. PRECIP WILL START OUT AS SNOW FOR
THE ENTIRE FA DUE TO THE COLDER AIR FROM CIRCULATION AROUND THE
HIGH PRESSURE…BUT AS THE RIDGE OF HIGH PRESSURE WEAKENS AND IS
PUSHED EASTWARD BY THE SFC LOW…WAA WILL CHANGE SNOW TO WINTRY
MIX LATE WEDNESDAY INTO WEDNESDAY NIGHT. 1000-500 HPA AND
1000-850 HPA THICKNESSES WILL INCREASE TO 534-546 AND 1290-1320
RESPECTIVELY WEDNESDAY NIGHT. GEFS PLUME DIAGRAMS SHOW MOST
MEMBERS STARTING PRECIP AS SNOW…CHANGING TO RAIN AND/OR
FREEZING RAIN AT THIS TIME.

THE SFC LOW WILL DEVELOP A SECONDARY LOW…TRANSFERRING ITS
ENERGY TO THIS LOW OFF THE ATLANTIC COAST. ECMWF AND GFS DIFFER
ON TIMING AND TRACK…BUT GFS SHOWING THE MORE AGGRESSIVE
TRANSLATION. AS SUCH…GFS HAS HIGH PRESSURE RIDGE BUILDING IN
FROM EASTERN CANADA ON FRIDAY…WHILE ECMWF HAVE UL TROUGH
REMAINING OVER THE AREA THROUGH LATE FRIDAY.

COME SATURDAY…BOTH MODELS SHOW DEEP UL LOW OVER NORTHERN GREAT
LAKES REGION PROGRESSING EASTWARD…ASSOCIATED WITH LARGE CLOSED
SFC LOW…WHICH WILL BRING MORE PRECIP TO THE REGION EARLY
SATURDAY THROUGH EARLY SUNDAY. THIS SYSTEM LOOKS TO HAVE MUCH
STRONGER WAA…CHANGING EARLY MORNING SNOW ON SATURDAY TO RAIN
FOR ALL BUT THE HIGH ELEVATIONS AHEAD OF THE COLD FRONT. BEHIND
THE COLD FRONT TEMPS WILL COOL TO ALLOW FOR LIGHT SNOWFALL
SATURDAY NIGHT INTO EARLY SUNDAY.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/…
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AS HIGH
PRESSURE CONTINUES OVER THE NE. MID AND HIGH LEVEL CLOUDS WILL
INCREASE OVERNIGHT INTO MONDAY…AHEAD OF A SFC LOW PRESSURE
SYSTEM TRAVELING EASTWARD OVER THE NORTHERN GREAT LAKES. A DECK
OF VFR LOW CLOUDS WILL MOVE INTO THE AREA LATE MONDAY MORNING
INTO MONDAY AFTERNOON. AS THE COLD FRONT ASSOCIATED WITH THE
AFOREMENTIONED LOW PRESSURE SYSTEM APPROACHES THE REGION MONDAY
AFTERNOON…A SLGT CHC OF -SHRASN EXISTS AT KGFL AND POSSIBLY
KALB.

WINDS WILL BECOME LGT TO CALM OVERNIGHT…INCREASING MONDAY
MORNING TO 5-10 KTS OUT OF THE S TO SSW.

OUTLOOK….
MON PM…VFR…SLGT CHC -SHRASN FOR KGFL.
TUE…VFR…NO SIG WX.
TUE NGT-THU…VFR/MVFR…CIG…CHC IFR IN -SN/-RA.
THU NGT-FRI…VFR…NO SIG WX.

&&

.HYDROLOGY…
NO HYDRO RELATED PROBLEMS ARE EXPECTED FOR THE NEXT 5 DAYS.

SOME GAGES ARE STILL BEING IMPACTED BY ICE ACROSS NORTHERN PORTIONS
OF THE HYDROLOGIC SERVICE AREA.

SOME VERY LIGHT SPOTTY RAIN OR SNOW (NORTH) TOMORROW AFTERNOON
AND EVENING WITH ANY MEASURABLE QPF AMOUNTS WELL UNDER QUARTER OF
AN INCH.

PRECIPITATION IS POSSIBLE WEDNESDAY INTO THURSDAY BUT THIS LOOKS
TO BE MOSTLY SNOW AND NOT ALL THAT HEAVY.

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…NAS
NEAR TERM…IAA/NAS
SHORT TERM…NAS
LONG TERM…KGM
AVIATION…KGM
HYDROLOGY…NAS

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