March 1, 2012 Forecast Discussion

000
FXUS61 KALY 010946
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
446 AM EST THU MAR 1 2012

.SYNOPSIS…
A COMPLEX STORM SYSTEM WILL CONTINUE TO IMPACT EASTERN
NEW YORK AND WESTERN NEW ENGLAND TODAY. ALL THE MIXED PRECIPITATION
THIS MORNING WILL TRANSITION TO SNOW…ESPECIALLY FROM THE GREATER
CAPITAL REGION…BERKSHIRES NORTH AND WEST…AS THE UPPER LOW MOVES
OVER UPSTATE NEW YORK AND NEW ENGLAND…AND THEN MOVES EASTWARD INTO
THE GULF OF MAINE THURSDAY NIGHT. HIGH PRESSURE WILL BRIEFLY BUILD
IN FROM THE OHIO VALLEY FOR FRIDAY WITH SEASONABLE TEMPERATURES AND
A BRIEF PERIOD OF DRY WEATHER.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 430 AM EST…MARCH HAS DEFINITELY COME IN LIKE A LION ACROSS
EASTERN NY AND WRN NEW ENGLAND. A COMPLEX…LONG DURATION STORM
SYSTEM CONTINUES TO IMPACT THE FORECAST AREA THIS MORNING. THE
PRIMARY SFC LOW AND ITS CLOSED COMPACT H500 UPPER LEVEL LOW ARE
MOVING EASTWARD ACROSS MICHIGAN AND THE ERN GREAT LAKES. THE WARM
FRONT TO THE SYSTEM STALLED OVER W-CNTRL PA…MD…AND NJ. SHORT-
WAVE ENERGY SHIFTED TO THE COAST WITH A SECONDARY LOW FORMING NEAR
SRN NJ THIS MORNING THAT IS MOVING E/SE SOUTH OF LONG ISLAND.

THE CONVECTION AHEAD OF THE SHORT-WAVE AND THE PRIMARY LOW MOVED
INTO E-CNTRL NY OVER THE PAST FEW HOURS. IT HAS PRODUCED VERY
HEAVY SNOWFALL OVER THE MOHAWK VALLEY….NRN CATSKILLS…SACANDAGA
REGION…SRN DACKS…LAKE GEORGE REGION…BERKSHIRES…SRN
VT…AND THE GREATER CAPITAL REGION. SOME MODERATE TO HEAVY SLEET
BRIEFLY MIXED IN OVER THE CAPITAL REGION. A SPOTTER IN DOLGEVILLE
IN HERKIMER COUNTY CALLED IN WITH SNOW RATES OF 1"/HR BACK AT 07Z.
WE HAVE EVEN HAD A FEW RUMBLES OF THUNDER OVER THE ERN CATSKILLS…AND
THE SRN BERKSHIRES WITHIN THE PAST HOUR. SNOWFALL RATES ARE LIKELY
IN THE 1 TO POSSIBLY 3"/HR. SEVERAL SPECIAL WEATHER STATEMENTS
HAVE BEEN ISSUED TO COVER THESE IMPRESSIVE SNOW RATES. THE RADAR
HAS SHOWED A FUZZY NATURE TO ECHOES FROM THE CAPITAL REGION NORTH
AND WEST OVER THE PAST SEVERAL HOURS…INDICATIVE OF A SNOW PTYPE.

THE NAM HAS BEEN THE MODEL OF CHOICE…AND WE CONTINUED TO FOLLOW
THE THERMAL FIELDS/BUFKIT PROFILES. THERE MAYBE A BRIEF LULL IN
THE PCPN OVER THE NEXT FEW HOURS…BUT WE ARE SEEING SEVERAL BANDS
OF PCPN UPSTREAM OVER LAKE ONTARIO AND W-CNTRL NY. THE UPPER LOW
IS EXPECTED TO MOVE OVER NRN NY BTWN 12Z-18Z. THE QG LIFT
GENERATED BY THE DIFFERENTIAL CYCLONIC VORTICITY OF THE UPPER LOW
WILL PRODUCE PERIODS OF MODERATE TO HEAVY SNOW. WE EXPECT ANY
LEFTOVER MIXED PCPN TO TRANSITION TO ALL SNOW AND RAIN BY ABOUT
14Z-15Z. THE STEEP MID LEVEL LAPSE RATES WITH THE UPPER LEVEL LOW
WILL ALLOW THE COLUMN TO COOL SUBSTANTIALLY WITH THE PCPN
TRANSITIONING TO ALL SNOW NORTH AND WEST OF THE MID HUDSON RIVER
VALLEY. BEFORE THAT TRANSITION WE CONTINUED TO BE CONCERNED ABOUT
SOME ELEVATED -FZRA OVER THE SE CATSKILLS…SRN BERKS…AND
LITCHFIELD HILLS. WE DROPPED THE ADVISORIES OVER THE MID HUDSON
VALLEY…SRN TACONICS…AND SRN LITCHFIELD COUNTY AS THE MESONET
OBSERVATIONS HAVE PRETTY MUCH RISEN ABOVE FREEZING. NRN LITCHFIELD
COUNTY IS A DIFFERENT STORY WHERE A FEW HOURS OF ICING…TURNING
TO SLEET AND SNOW WILL LIKELY OCCUR BY THE LATE MORNING.

ALL THE WARNING REMAINS UP…WITH AN ADDITIONAL 4 TO 10 INCHES OF
SNOW EXPECTED NORTH AND WEST OF THE CAPITAL REGION…INCLUDING THE
SRN GREEN MTNS. ANOTHER 3 TO 6 INCHES IS ANTICIPATED OVER THE
CAPITAL REGION…N-CTRNL TACONICS…ANS SRN BERKS. 4-8 INCHES IS
LIKELY OVER THE CATSKILLS. WE ARE EXPECTING A COATING TO AN INCH
OR TWO OVER THE SOUTHERN MOST ZONES WITH A MIXTURE WITH RAIN UNTIL
THE COLUMN COOLS DOWN.

WE WENT WITH THE METMOS MAX TEMPS TODAY WITH HIGHS IN THE MID AND
UPPER 30S OVER THE VALLEYS…AND HILLS…WITH M20S TO L30S OVER
THE MTNS.

IT IS INTERESTING DESPITE THE STRONG E TO SE WINDS OVER THE SRN
GREENS…AND NRN BERKS…THE HEAVY SNOW CONTINUES TO MOVE INTO
THESE AREAS. THE E/SE UPSLOPE IS LIKELY TREMENDOUS RIGHT
NOW…AND WE WOULD BE SURPRISE IF THE ERN DACKS/SACANDAGA REGION
GETS CLOSE TO 10 TO 20 INCHES OF SNOW BEFORE ALL IS SAID AND DONE.

TONIGHT…THE UPPER LOW AND ITS ATTENDANT PRIMARY SFC LOW MOVE
EAST OF NEW ENGLAND INTO THE GULF OF MAINE. SFC HIGH PRESSURE
WILL TRY TO BUILD IN FROM THE OH VALLEY. WESTERLY UPSLOPE SNOWFALL
WILL PERSIST ALONG THE WRN SPINE OF THE SRN GREENS AND WRN DACKS
BEFORE TAPERING OFF. ADDITIONAL SNOWFALL AMOUNTS WILL BE LIGHT
WITH COATING TO A FEW INCHES. LOWS WILL RANGE FROM THE TEENS TO
LOWER 20S OVER THE FCST AREA.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/…
ACTIVE WEATHER EXPECTED FOR THE FIRST HALF OF THE WEEKEND AFTER A
LULL IN THE ACTION ON FRIDAY.

ON FRIDAY…EXPECT HIGH PRESSURE WILL BE CENTERED OVER THE REGION
EARLY IN THE DAY AND THEN SLIDE OFF THE EAST COAST DURING THE
AFTERNOON. HIGHS ON FRIDAY ARE EXPECTED TO BE IN THE 30S ACROSS THE
NORTHEAST HALF OF THE FA WITH THE UPPER 30S TO MID 40S ACROSS THE
SOUTHWEST HALF OF THE FA.

FRIDAY NIGHT AND SATURDAY…A MID LEVEL TROUGH IS EXPECTED TO LIFT
EAST NORTHEAST FROM THE UPPER GREAT LAKES INTO SOUTHEAST CANADA…
AS THE SURFACE LOW TRACKS THROUGH THE UPPER GREAT LAKES AND EASTERN
QUEBEC LIFTING A WARM FRONT TOWARD OUR REGION SATURDAY MORNING AND
DRAGGING AN OCCLUDED FRONT THROUGH OUR REGION SATURDAY AFTERNOON.
THE GFS AND ECMWF HAVE A SECONDARY LOW DEVELOPING ON THE TRIPLE
POINT. THIS WILL NEED TO BE WATCHED CLOSELY AS THIS TYPE OF SCENARIO
HAS THE POTENTIAL TO INCREASE THE QPF DRAWING MORE MOISTURE OFF THE
ATLANTIC OCEAN.

PTYPE WILL BE ANOTHER ISSUE WITH THE GEFS AND SREF PLUMES INDICATING
A MAINLY RAIN EVENT…ALTHOUGH IT MAY BE INITIALLY COLD ENOUGH FOR
SOME LIGHT SNOW AT THE ONSET WHEN PCPN ARRIVES LATER FRIDAY NIGHT.
PARTIAL THICKNESS VALUES AND BUFKIT MODEL SOUNDINGS WOULD SUPPORT
SNOW AND SLEET CHANGING TO RAIN WITH TEMPS RISING OVERNIGHT AND HAVE
GONE IN THIS DIRECTION WITH PTYPE IN THE GRIDS. THIS ALSO MAKES
SENSE GIVEN THAT STRONG WARM AIR ADVECTION IS EXPECTED WITH A WARM
FRONT LIFTING NORTH TOWARD THE REGION ON SATURDAY…THUS A QUICK
CHANGEOVER TO RAIN IS LIKELY…BEFORE CHANGING BACK TO SCATTERED
SNOW SHOWERS SATURDAY NIGHT IN THE WAKE OF THE OCCLUDED FRONT WHICH
IS EXPECTED TO BE WELL EAST OF THE FA BY LATE SATURDAY. SOME
STRONG GUSTY SOUTHERLY WINDS ARE POSSIBLE LATE FRIDAY NIGHT INTO
SATURDAY MORNING AND WILL INCLUDE MENTION IN THE HWO. MOST FAVORED
AREAS WOULD BE HIGHER TERRAIN AS WELL AS AREAS PRONE TO
SOUTH-SOUTHEAST WINDS SUCH AS THE TACONICS…BERKSHIRES AND SOUTHERN
GREEN MOUNTAINS INCLUDING KAQW AND KDDH. NAM 0-30 MB AGL WINDS OVER
40 KTS ACRS THE AFOREMENTIONED AREAS. THUS WIND ADVISORIES MAY BE
NEEDED. IN ADDITION HAVE ADDED ISOLATED THUNDERSTORMS TO THE GRIDS
LATE FRIDAY NIGHT THROUGH SATURDAY MORNING AS SHOWALTER INDICES
AROUND OR SLIGHTLY BELOW ZERO. EXPECT LOWS FRIDAY NIGHT IN THE UPPER
30S TO AROUND 40 WITH THE LOWS OCCURRING MID EVENING AND THEN TEMPS
RISING OVERNIGHT. HIGHS ON SATURDAY ARE EXPECTED TO RANGE FROM THE
LOW TO MID 40S NORTHWEST TO THE MID TO UPPER 50S SOUTHEAST WITH
ISOLATED 60 DEGREE READINGS POSSIBLE. ANOTHER CONCERN WILL BE THE
POTENTIAL FOR SIGNIFICANT STREAM AND RIVER RISES ON SATURDAY WHICH
WILL BE ADDRESSED IN THE HYDROLOGY SECTION BELOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/…
SATURDAY NIGHT…EXPECT MAINLY DRY CONDITIONS AS WEAK HIGH PRESSURE
WILL BUILD ACROSS THE SOUTHERN HALF OF THE FA IN THE WAKE OF THE
OCCLUDED FRONT. NORTHWEST PORTION OF FA MAY SEE SOME SCATTERED SNOW
SHOWERS IN ADVANCE OF A SECONDARY FRONT DROPPING SOUTHEAST FROM
ONTARIO ALONG WITH SOME LAKE ENHANCEMENT OF THESE SNOW SHOWERS.
EXPECT LOWS IN THE UPPER TEENS TO UPPER 20S.

SUNDAY AND SUNDAY NIGHT…THE SECONDARY COLD FRONT IS EXPECTED TO DROP
SOUTH FROM THE SAINT LAWRENCE VALLEY SUNDAY MORNING THROUGH OUR
REGION LATE SUNDAY AND SUNDAY NIGHT. EXPECT SCATTERED RAIN OR SNOW
SHOWERS MAINLY ACROSS NORTHERN HALF OF FA SUNDAY INTO SUNDAY
EVENING. ONCE AGAIN SOME LAKE ENHANCEMENT OF THE SNOW IS EXPECTED
AND HAVE PLACED LIKELY POPS ON SUNDAY ACROSS THE NORTHWESTERN
ADIRONDACKS. EXPECT HIGHS ON SUNDAY TO BE IN THE LOWER 30S NORTHWEST
TO THE MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT IN THE UPPER SINGLE
DIGITS NORTHWEST TO MID 20S SOUTHEAST.

MONDAY THROUGH WEDNESDAY LOOKS MAINLY DRY AT THIS POINT IN TIME WITH
A LARGE RIDGE OF HIGH PRESSURE BUILDING ACROSS THE REGION. EXPECT A
SIGNIFICANT WARMING TREND THROUGH THE PERIOD AS THE RIDGE OF HIGH
PRESSURE MOVES OVER US AND THEN SLIDES EAST SETTING UP A RETURN
FLOW. HIGHS ARE EXPECTED TO RISE FROM THE MID 20S TO UPPER 30S ON
MONDAY TO THE MID 40S TO UPPER 50S ON WEDNESDAY. LOWS ARE EXPECTED
TO BE IN THE SINGLE DIGITS AND TEENS MONDAY NIGHT AND 20S TO AROUND
30 TUESDAY NIGHT.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/…
…A WINTER STORM WILL CONTINUE TO IMPACT ALL THE TERMINALS
THROUGHOUT MUCH OF TODAY AS THE ACTUAL UPPER AIR LOW AND ENERGY
MOVE ACROSS THE REGION…

KGFL…WILL SEE MAINLY IFR OR LIFR THROUGH MIDDAY AS A SECOND SURGE
OF SNOW…MIXED WITH SLEET MOVES BACK INTO THE TERMINAL BEFORE THE
AM PEAK. SNOW WILL TAPER TO SNOW SHOWERS DURING THE AFTERNOON…SO
CONDITIONS LOOK TO SLOWLY IMPROVE BACK TO MVFR WITHOUT FUEL
RESTRICTIONS. THE SURFACE WIND WILL BE LIGHT FROM THE NORTHEAST.
WITH A PRETTY STRONG SOUTHEASTERLY WIND ABOUT 2500 FEET OFF THE DECK
THROUGH EARLY MORNING…WIND SHEAR THRESHOLD WILL BE CLOSED BUT IT
LOOKS NOT TO BE FULLY REALIZED.

KALB…WILL ALSO SEE MAINLY IFR…OCCASIONALLY LIFR…AS A SECOND
BATCH OF SNOW…MIXED WITH SLEET…MOVES BEFORE THE MORNING PEAK AS
WELL. SNOW WILL TAPER TO SNOW SHOWERS DURING THE AFTERNOON…SO
CONDITIONS LOOK TO SLOWLY IMPROVE BACK TO MVFR WITHOUT FUEL
RESTRICTIONS. THE SURFACE WIND WILL BE LIGHT FROM THE NORTHEAST.
WITH A PRETTY STRONG SOUTHEASTERLY WIND ABOUT 2500 FEET OFF THE DECK
THROUGH EARLY MINORING…WIND SHEAR THRESHOLD WILL BE CLOSE BUT IT
LOOKS NOT TO BE FULLY REALIZED.

KPOU…WILL BE LITTLE WARMER THOUGH THE COLUMN SO IT LOOKS MORE LIKE
MORE RAIN THAN SNOW AND SLEET. THEREFORE IFR CONDITIONS WILL BE
OCCASIONAL BUT WE THINK MUCH OF THE TIME COULD SEE MVFR WITH FUEL
RESTRICTIONS (CIG BELOW OVC020 AND OR VISIBLITY BELOW 3SM). AS THE
COLUMN COOLS THERE MIGHT BE TENDENCY TO GO MORE TO SNOW RIGHT AROUND
OR SHORTLY AFTER THE MORNING COMMUTE. THEN…AS DRIER AIR SLOWLY
MOVES IN CONDITIONS SHOULD IMPROVE TO HIGH END MVFR LATER DURING THE
AFTERNOON (NO FUEL RESTRICTIONS). THE SURFACE WIND WILL BE LIGHT
FROM THE NORTHEAST. WITH A PRETTY STRONG SOUTHEASTERLY WIND ABOUT
2500 FEET OFF THE DECK…WIND SHEAR THRESHOLD WILL BE CLOSE BUT IT
LOOKS NOT TO BE FULLY REALIZED.

ANY AND ALL PRECIPITATION SHOULD DWINDLE AROUND OR A LITTLE AFTER
THE EVENING PEAK. MVFR CLOUDS MIGHT LINGER AWHILE LONGER INTO
THURSDAY NIGHT.

OUTLOOK…
FRI…VFR. NO SIG WX.
FRI NIGHT-SAT…SUB-VFR CIG. RAIN SHOWERS LIKELY.
SAT NIGHT-SUN…VFR. NO SIG WX.
SUN NIGHT…VFR. CIG. SCHC IFR -SHSN.
MON…VFR NO SIG WX.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT 48 HOURS ON THE MAIN STEM
RIVERS. SOME HYDRO GAGES ARE STILL BEING IMPACTED BY ICE FROM THE
MOHAWK RIVER VALLEY NORTHWARD INTO THE ADIRONDACKS. SOME PROBLEMS
MAY ARISE ON THE WEEKEND.

A HEAVY PRECIPITATION EVENT IS ONGOING AND WILL CONTINUE THROUGH
TODAY WITH TOTAL QPF AROUND AN INCH TO AN INCH AND A QUARTER.
THERE COULD BE SOME LOCALLY HIGHER AMOUNTS. A LARGE PORTION OF THE
PRECIPITATION WILL FALL AS SNOW AND SLEET…MIXING WITH SOME RAIN
OR FREEZING RAIN ESPECIALLY ACROSS AREAS SOUTH OF THE CAPITAL
REGION. SEVERAL INCHES OF SNOW AND SLEET ARE EXPECTED FOR MUCH OF
THE REGION…SO NOT MUCH RIVER RESPONSE IS ANTICIPATED EXCEPT FOR
SOME MINOR RISES ACROSS SOUTHERN AREAS WHERE SOME OF THE PRECIP
WILL FALL AS RAIN AND THERE WILL SLIGHT RUNOFF.

DRY WEATHER WILL BRIEFLY RETURN ON FRIDAY…BEFORE ANOTHER SYSTEM
BRINGS A ROUND OF RAIN AND MIXED PRECIP TO THE REGION FRIDAY NIGHT
WITH PLAIN RAIN ON SATURDAY. THERE COULD BE SOME DECENT SNOW MELT
AS TEMPERATURES SOAR ABOVE NORMAL INTO THE 40S AND 50S COUPLED
WITH STRONG SOUTHERLY WINDS AND DEWPOINTS RISING INTO THE 40S.

WE WILL MENTION IN THE HWO…THE POSSIBILITY OF FLOODING WITH AT
LEAST MINIMUM SIGNIFICANT RISES ON STREAMS AND RIVERS WITH SNOW
MELT COMBINED WITH MODERATE TO HEAVY PRECIPITATION.

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…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR CTZ001.
NY…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-038>043-047>054-058>061-063-082>084.
MA…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MAZ001-
025.
VT…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR
VTZ013>015.

&&

$$
SYNOPSIS…WASULA
NEAR TERM…WASULA
SHORT TERM…11
LONG TERM…11
AVIATION…HWJIV
HYDROLOGY…JPV/WASULA

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