January 25, 2012 Forecast Discussion

000
FXUS61 KALY 260017
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
717 PM EST WED JAN 25 2012

.SYNOPSIS…
A WEAK UPPER LEVEL DISTURBANCE WILL PASS SOUTH OF THE
REGION OVERNIGHT…BRINGING CLOUDS…AND PERHAPS A FEW SNOW SHOWERS
OR FLURRIES. A MORE POTENT STORM SYSTEM DEVELOPING ACROSS THE LOWER
MISSISSIPPI VALLEY WILL TRACK NORTHEAST TOWARD THE EASTERN GREAT
LAKES THURSDAY INTO FRIDAY. THIS SYSTEM WILL BRING MAINLY RAIN TO
AREAS SOUTH OF ALBANY THURSDAY NIGHT AND EARLY FRIDAY…WITH A
WINTRY MIX CHANGING TO RAIN FOR AREAS NORTH AND EAST OF ALBANY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/…
AS OF 7 PM…LOW STRATUS CLOUDS REMAIN TRAPPED BENEATH A STRONG
INVERSION ACROSS MUCH THE FORECAST AREA. EXCEPT THESE CLOUDS TO
REMAIN IN PLACE THROUGH MUCH OF THE NIGHT. HIGHER LEVEL CLOUDS
WILL MOVE IN OVERHEAD TONIGHT. ONLY MINOR ADJUSTMENTS MADE MAINLY
TO CLOUD COVER AND EXPANDED THREAT FOR FLURRIES.

AS OF 445 PM EST…LOW CLOUDS REMAIN TRAPPED BENEATH STRONG
INVERSION ACROSS CENTRAL AND NORTHERN AREAS. THERE HAS BEEN SOME
EROSION FROM THE SOUTH OVER THE LAST FEW HOURS.
UNFORTUNATELY…MID LEVEL CLOUDS ARE RAPIDLY APPROACHING FROM THE
W…SO ANY CLEARING WILL GIVE WAY TO MOSTLY CLOUDY SKIES BY LATER
THIS EVENING ACROSS THE ENTIRE REGION.

THE MID LEVEL CLOUDS ARE ASSOCIATED WITH A BURST OF MID LEVEL WARM
ADVECTION…WELL E AND SE OF AN SHORTWAVE TRAVERSING N OF THE
GREAT LAKES. SOME OF THIS MOISTURE HAS BEEN TRANSPORTED NORTH FROM
THE MORNING CONVECTION ACROSS THE LOWER MS VALLEY. THIS MID LEVEL
ISENTROPIC LIFT MAY SUPPORT SOME SPOTTY LT SNOW OR FLURRIES ACROSS
THE EASTERN CATSKILLS…AND POSSIBLY THE MID HUDSON VALLEY REGION
LATER THIS EVENING THROUGH THE EARLY MORNING HOURS. HAVE THEREFORE
INDICATED SLIGHT CHC TO VERY LOW CHC POPS IN THIS AREA FOR THIS
POSSIBILITY. ELSEWHERE…THE COMBINATION OF MID LEVEL CLOUDS
SEEDING/FEEDING THE LINGERING LOWER CLOUDS BENEATH SHOULD ALLOW
FOR SOME FLURRIES OR VERY LIGHT SNOW SHOWERS TO REDEVELOP FURTHER
N AND E AS WELL…WHICH HAVE BEEN INDICATED IN THE FORECAST.
A DUSTING COULD OCCUR IN SOME AREAS WHERE FLURRIES/SNOW SHOWERS
DEVELOP…ALTHOUGH AMTS OF A FEW TENTHS OF AN INCH COULD OCCUR IN
THE EASTERN CATSKILLS.

ASSUMING MOSTLY CLOUDY SKIES PERSIST…HAVE GENERALLY GONE ABOVE
THE MAV/MET MOS FOR MINS…EXCEPT CLOSE TO THE MET MOS ACROSS
NORTHERN AREAS WHERE CLOUDS MAY THIN OUT TOWARD DAYBREAK.
SO…EXPECT MAINLY 20S ACROSS THE REGION…AND TEENS ACROSS THE
SOUTHERN ADIRONDACKS.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/…
THU…THE BEST CHANCE FOR SOME SUNSHINE WILL BE IN THE
MORNING…BUT WILL BE A VERY SHORT WINDOW…AS HIGH/MID LEVEL
CLOUDS THICKEN RAPIDLY FROM LATE MORNING INTO THE AFTERNOON. GIVEN
AN EVOLVING WARM ADVECTION PATTERN…AND AS WINTNESSED BY OTHER
RECENT SIMILAR WARM ADVECTION PATTERNS…HAVE BOOSTED POPS INTO
THE CHC TO LIKELY RANGE FROM ALBANY SOUTH AND WEST BY LATE
AFTERNOON/EARLY EVENING…AND WOULD NOT BE SURPRISED IF EVEN THIS
IS TOO SLOW…AS WARM ADVECTION PRECIP OFTEN DEVELOPS MUST FASTER
THAN MOST MODELS INDICATE. P-TYPE AT START SHOULD BE IN THE FORM
OF RAIN ACROSS SOUTHERN AREAS…EXCEPT FOR A RAIN/SLEET MIX IN THE
CATSKILLS AND BERKSHIRES…AS WELL AS WITHIN THE CAPITAL REGION.
MAX TEMPS SHOULD REACH THE MID 30S TO NEAR 40 IN VALLEY
REGIONS…AND MAINLY LOWER TO MID 30S ACROSS HIGHER
ELEVATIONS…EXCEPT POSSIBLY ONLY NEAR 30 ACROSS THE SOUTHERN
ADIRONDACKS. SHOULD THE PRECIP DEVELOP MORE QUICKLY…SOME SNOW
COULD OCCUR FOR AREAS N OF THE MOHAWK RIVER VALLEY.

THU NT…COMPLEX SCENARIO EVOLVING FOR THIS TIME PERIOD…ESP FOR
AREAS N AND E OF ALBANY. WARM AIR IS EXPECTED TO THURST NORTHWARD
ALOFT…MAINLY AOA 850 MB. HOWEVER…BENEATH THIS…ESP BELOW 925
MB…COLD AIR MAY LINGER…ESP IN SOME VALLEY REGIONS ACROSS SE
VT…AND POSSIBLY PORTIONS OF THE SOUTHERN DACKS/UPPER HUDSON
RIVER VALLEY…DESPITE THE STRONG SOUTH/SOUTHEAST WINDS DEVELOPING
ALOFT. IN THESE AREAS…A BRIEF MIX OF SNOW/SLEET SHOULD CHANGE TO
FREEZING RAIN TOWARD OR AFTER MIDNIGHT…WITH FREEZING RAIN
POSSIBLY LINGERING IN SOME AREAS UNTIL AROUND DAYBREAK FRIDAY.
THIS COULD PRODUCE ICE ACCRETION OF ONE QUARTER…TO LESS THAN ONE
HALF INCH…ESP IN SE VT/EASTERN WINDHAM CO/.
EVENTUALLY…WINTER WX ADVISORIES WILL LIKELY BE NEEDED FOR
PORTIONS OF THE SOUTHERN DACKS/UPPER HUDSON RIVER VALLEY AND SE VT
FOR THU NT…IF NOT A BIT FURTHER S INTO THE BERKSHIRES…WHERE
ONE TENTH TO ONE QUARTER OF AN INCH OF ICE IS POSSIBLE. SNOW/SLEET
ACCUMS SHOULD REMAIN LIGHT…GENERALLY AROUND AN INCH…EXCEPT
LOCALLY 1-3 INCHES POSSIBLE ACROSS THE EASTERN ADIRONDACKS.
OVERALL…WE HAVE FOLLOWED CLOSE TO THE ECMWF OVERALL FOR QPF AND
TEMPS…WHICH IS ON THE WARMER SIDE OF THE ENVELOPE OF SOLUTIONS.
SHOULD COLDER AIR NAH TIGHTER THAN EXPECTED…MORE SIGNIFICANT
ICING COULD OCCUR IN PORTIONS OF THE SOUTHERN ADIRONDACKS AND SE
VT. FOR TEMPS…GENERALLY SIDED CLOSE TO THE MAV MOS FOR
MINS…WHICH SHOULD OCCUR IN THE EVENING…WITH RISING TEMPS
OVERNIGHT. THE OTHER ISSUE WILL BE LOCALLY STRONG WINDS ACROSS
PORTIONS OF THE GREEN MOUNTAINS AND BERKSHIRES…GIVEN THE
DEVELOPING LOW LEVEL JET MAX APPROACHING/PASSING LATE AT NIGHT. IN
THESE AREAS…SOME GUSTS OF 35-45 MPH ARE POSSIBLE.

FRI-FRI NT…WILL INDICATE LIKELY TO CAT POPS INTO FRI MORNING…ESP
BASED ON THE 12Z/ECMWF WHICH IS SLOWER THAN OTHER
MODELS…INDICATING A MORE WAVY NATURE TO THE COLD/OCCLUDED FRONT
APPROACHING FROM THE W. THIS COULD ALSO LEAD TO GREATER QPF…WITH
RAINFALL AMTS OF 1.5-2 INCHES POSSIBLE IN SOME AREAS. SEE HYDRO
DISCUSSION FOR MORE INFO. RAIN SHOULD TAPER TO SHOWERS IN THE
AFTERNOON…WITH SNOW SHOWERS OCCURRING IN NORTHERN AREAS AS TEMPS
COOL ALOFT. FOR MAX TEMPS…SIDED CLOSER TO THE MAV MOS. SOME LAKE
EFFECT/UPSLOPE SNOW SHOWERS MAY LINGER FRI AFTN INTO FRI EVE.
THEN…SNOW SHOWERS SHOULD DIMINISH IN AREAL COVERAGE AS A WEAK
LOW LEVEL RIDGE APPROACHES. BUT…MID LEVEL CLOUDS MAY INCREASE
BEFORE DAYBREAK SAT AHEAD OF A FAST MOVING UPPER LEVEL
DISTURBANCE APPROACHING FROM THE GREAT LAKES. FOLLOWED MAV MOS FOR
FRI NT MINS.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/…
EXPECT THE LONG TERM PERIOD TO FEATURE MAINLY DRY CONDITIONS WITH
TEMPS AVERAGING ABOVE NORMAL.

A SERIES OF CLIPPER TYPE SYSTEMS ARE EXPECTED TO IMPACT MAINLY
NORTHERN PORTIONS OF THE FA DURING THE LONG TERM PERIOD WITH THE
SOUTHERN TWO THIRDS OF THE FA REMAINING MAINLY DRY EXCEPT FOR SUNDAY
AND SUNDAY NIGHT WHEN MOST OF THE FA WILL HAVE A CHANCE OF SNOW
SHOWERS ALTHOUGH SOUTHERN PORTIONS OF THE FA MAY HAVE SCATTERED RAIN
SHOWERS SUNDAY AFTERNOON WITH THE SECOND CLIPPER SYSTEM. NORTHERN PORTIONS
OF THE FA CAN EXPECT MAINLY SCATTERED SNOW SHOWERS SATURDAY
AFTERNOON WITH THE FIRST CLIPPER SYSTEM AND AGAIN LATE TUESDAY WITH
THE THIRD CLIPPER SYSTEM WHICH WILL BE MOVING INTO THE UPPER GREAT
LAKES REGION.

EXPECT HIGHS ON SATURDAY AND SUNDAY TO RANGE FROM THE UPPER 20S AND
LOWER 30S NORTHWEST TO THE LOWER 40S SOUTHEAST. HIGHS ON MONDAY WILL
BE COOLER IN THE WAKE OF THE SECOND CLIPPER SYSTEM RANGING FROM THE
LOW TO MID 20S NORTHWEST TO LOW TO MID 30S SOUTHEAST WITH HIGHS ON
TUESDAY RANGING FROM THE LOWER 30S NORTHWEST TO LOWER 40S SOUTHEAST.
LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM THE TEENS NORTHWEST
TO 20S SOUTHEAST WITH LOWS SUNDAY NIGHT AND MONDAY NIGHT RANGING
FROM THE UPPER SINGLE DIGITS AND LOWER TEENS NORTHWEST TO LOW TO MID
20S SOUTHEAST.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/…
LOW STRATUS CLOUDS REMAIN TRAPPED BENEATH A STRONG INVERSION AT KALB
AND KGFL. EXCEPT THESE MVFR CLOUDS TO REMAIN IN PLACE THROUGH MUCH
OF THE NIGHT WITH THEM BREAKING UP THURSDAY MORNING. HIGHER LEVEL
CLOUDS WILL CONTINUE TO MOVE IN OVERHEAD TONIGHT. CEILINGS WILL
LOWER TO MVFR AS WARM AIR ADVECTION PRECIPITATION MOVES IN/DEVELOPS
OVER THE AREA BY LATE AFTERNOON AS A WARM FRONT APPROACHES AND
LOW LEVEL JET MOVES IN. WESTERLY WINDS WILL BECOME LIGHT AND
VARIABLE TO CALM TONIGHT WITH A LIGHT SOUTHEAST FLOW DEVELOPING
THURSDAY AFTERNOON.

OUTLOOK…
THU NT-FRI AM…MVFR/IFR. MIXED PCPN TRANSITIONING TO -RA.
FRI AFTN…VFR/MVFR. CHC -SHRA EARLY.
FRI NT-SAT…VFR. NO SIG WX.
SUN…VFR/MVFR. CHC -SHSN/-SHRA.
MON…VFR. NO SIG WX.

&&

.HYDROLOGY…
A COMPLEX STORM SYSTEM WILL APPROACH THE REGION FROM THE SOUTHWEST
LATE THU INTO FRI. OVERALL QPF HAS INCREASED REGIONWIDE…WITH
AVERAGE AMTS OF AROUND AN INCH EXPECTED. SOME OF THIS WILL FALL AS
A WINTRY MIX ACROSS NORTHERN AREAS. HOWEVER…SHOULD THE
12Z/ECMWF PROVE CORRECT…EVEN HIGHER AMTS COULD OCCUR…PERHAPS
AS MUCH AS 1.5 TO 2 INCHES…HIGHEST ACROSS WESTERN NEW ENGLAND
AND POSSIBLY THE MID HUDSON VALLEY REGION…WITH A GOOD PORTION
OCCURRING AS RAIN. SHOULD THESE HIGHER AMTS OCCUR…THEN MINOR
FLOODING COULD OCCUR ON SOME RIVERS/STREAMS ON FRIDAY. IN
ADDITION…GIVEN THE RELATIVELY FROZEN GROUND STILL ACROSS MUCH OF
THE REGION…THERE SHOULD BE LITTLE ROOM FOR ASBORPTION…WHICH
WILL LIKELY LEAD TO WIDESPREAD PONDING OF WATER IN LOW
LYING…POOR DRAINAGE AND URBAN AREAS…AND ON ROADWAYS SHOULD
HEAVIER RAINFALL AMOUNTS OCCUR.

GENERALLY DRY CONDITIONS ARE THEN EXPECTED FOR SAT INTO SUNDAY.

&&

.ALY WATCHES/WARNINGS/ADVISORIES…
CT…NONE.
NY…NONE.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…KL
NEAR TERM…IAA/KL
SHORT TERM…KL
LONG TERM…11
AVIATION…IAA/FRUGIS
HYDROLOGY…KL

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