December 22, 2012 Forecast Discussion

000
FXUS61 KALY 221502
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1002 AM EST SAT DEC 22 2012

.SYNOPSIS…
A POWERFUL STORM SYSTEM LOCATED ACROSS SOUTHERN QUEBEC WILL SLOWLY
DRIFT NORTHWARD THIS AFTERNOON THROUGH SUNDAY. THIS STORM WILL KEEP
CLOUDS…STRONG WINDS…AS WELL AS SNOW SHOWERS AND FLURRIES
ACROSS THE REGION TODAY…WITH THE MOST PERSISTENT SNOW SHOWERS
EXPECTED ACROSS HIGHER ELEVATIONS. AS THE STORM MOVES FURTHER AWAY
FROM THE REGION TONIGHT AND SUNDAY…SNOW SHOWERS AND STRONG WINDS
WILL DECREASE…WITH SOME BREAKS OF SUNSHINE POSSIBLE ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 945 AM EST…A SFC TROUGH OR SECONDARY COLD FRONT WAS
MOVING ACROSS W-CNTRL NEW ENGLAND THIS MORNING. NARROW BANDS OF
SNOW SHOWERS CONTINUE IN THE WAKE OF THE TROUGH IN THE CYCLONIC
FLOW. ALSO…OROGRAPHIC WESTERLY UPSLOPE FLOW SNOWS CONTINUE ALONG
THE SPINE OF THE WRN DACKS…AND SRN GREENS AND TACONICS. WE
SLIGHTLY BROADENED THE RANGE IN THE WRN DACKS TO 3 TO 8". A COCORAHS
REPORT CAME IN WITH 4" OF SNOW AT INLET OVER THE PAST 24
HOURS…SOME OF THAT SNOW MAY BE FROM LATE YESTERDAY MORNING INTO
THE AFTERNOON. ALSO…THE CAROGA LAKE REPORT INCLUDES 3 INCHES
FROM YESTERDAY (5.5 INCH REPORT FROM LATEST PNS). PORTIONS OF THE
NRN CATSKILLS…INCLUDING SCHOHARIE COUNTY MAY GETS 1 TO 3 INCHES
OF SNOW IN THE NARROW BANDS.

LOCALLY HEAVY SNOWS WILL BE POSSIBLE ACROSS PORTIONS OF THE
WESTERN ADIRONDACKS AND MOHAWK VALLEY…AS WELL AS ACROSS
HIGHER…WEST FACING ELEVATIONS OF THE SOUTHERN GREEN MTNS INTO
THE BERKSHIRES. SNOWFALL ACCUMS OF 3 TO 7 INCHES MAY OCCUR IN
LOCALIZED AREAS OF THE SRN GREENS…AS A DEEP MOIST LAYER THROUGH
700 MB IS STRONGLY LIFTED ACROSS THE TERRAIN DUE TO THE STRONG
WESTERLY LOW LEVEL FLOW. IN BETWEEN THESE AREAS…DOWNSLOPING
WESTERLY WINDS SHOULD ALLOW SNOW SHOWERS TO REMAIN SOMEWHAT
LIMITED IN AREAL COVERAGE. THE COMBINATION OF STRONG WINDS…AND
FALLING SNOW WILL LIKELY LEAD TO BLOWING/DRIFTING OF THE
SNOW…POTENTIALLY LIMITING VISIBILITIES AT TIMES TO ONE HALF MILE
OR LESS.

THE WIND ADVISORY WILL CONTINUE…BUT ACHIEVING WIDESPREAD WIND
GUSTS OF 45-50 MPH MAY BE LIMITED DUE TO THE DEGREE OF CLOUD COVER
IN THE MOIST CYCLONIC FLOW ALOFT. HOWEVER…A WIND ADVISORY WILL
CONTINUE THIS AFTERNOON INTO EARLY THIS EVENING.

STRONG WEST TO NORTHWEST WINDS WILL MATERIALIZE…AS THE DEEP
STORM SYSTEM LIFTS FURTHER NORTHWARD…AND HIGH PRESSURE BUILDS IN
FROM THE SOUTHWEST. THE TIGHTENING PRESSURE GRADIENT BETWEEN THESE
TWO FEATURES WILL TRANSLATE FROM SOUTH TO NORTH ACROSS THE REGION
LATE THIS MORNING INTO THIS EVENING. FUNNELING DUE TO A FAVORABLE
ALIGNMENT OF THE WEST/NORTHWEST LOW LEVEL FLOW INTERACTING WITH
THE TERRAIN OF THE MOHAWK RIVER VALLEY WILL LIKELY FURTHER ENHANCE
THIS GUST POTENTIAL…ESPECIALLY AROUND…OR JUST AFTER SUNSET IN
THE ERN CATSKILLS…AND THE CAPITAL DISTRICT.

TEMPS MAY REACH THERE PEAK IN NORTH AND WEST OF THE CAPITAL REGION
TOWARDS NOONTIME…WITH MAXES IN THE 20S TO L30S. HIGHS SOUTH AND
EAST OF THE CAPITAL REGION WILL VARY FROM THE LOWER 30S TO NEAR
40F.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/…
TONIGHT…MODELS INDICATE POTENTIAL DRYING ABOVE 700 MB FROM WEST
TO EAST DURING THE EVENING HOURS. AS THIS OCCURS…WE EXPECT THE
AREAL COVERAGE OF SNOW SHOWERS TO DECREASE FROM THE HUDSON VALLEY
REGION EAST…INTO WESTERN NEW ENGLAND AS ANY SEEDER/FEEDER
PROCESSES TAPER OFF. THIS SHOULD ALLOW THE OROGRAPHIC SNOWS ACROSS
WESTERN NEW ENGLAND TO TAPER OFF BY LATER THIS EVENING.
HOWEVER…AS THE LOW LEVEL FLOW VEERS SLIGHTLY INTO THE
WEST/NORTHWEST…A GREATER OVER LAKE TRAJECTORY SHOULD
DEVELOP…WITH SOME ADDED LAKE CONTRIBUTIONS FROM HURON/GEORGIAN
BAY POSSIBLE. THIS MAY ALLOW FOR SOMEWHAT MORE ORGANIZED SNOWBANDS
TO DEVELOP LATER TONIGHT…WHICH COULD IMPACT PORTIONS OF EXTREME
SOUTHWEST HERKIMER CO…AND WESTERN SCHOHARIE VALLEY LATER
TONIGHT. WILL KEEP POPS WITHIN THE HIGH CHC RANGE IN THESE
AREAS…WHILE TAPERING TO SLIGHT CHC OR LESS ELSEWHERE. STRONG
WINDS WILL GRADUALLY DIMINISH OVERNIGHT…ALTHOUGH GUSTS OF 25-35
MPH WILL REMAIN POSSIBLE THROUGHOUT THE NIGHT WITHIN THE IMMEDIATE
CAPITAL REGION/MOHAWK VALLEY AND BERKSHIRES. EXPECT MINS TO FALL
INTO THE LOWER/MID 20S IN VALLEY REGIONS…AND TEENS ACROSS THE
SOUTHERN ADIRONDACKS AND SOME HIGHER ELEVATIONS ACROSS WESTERN NEW
ENGLAND.

SUNDAY-SUNDAY NIGHT…THE LOW LEVEL FLOW IS EXPECTED TO BACK
INTO THE WEST…AND PERHAPS WEST/SOUTHWEST DURING SUNDAY…BEFORE
VEERING SLIGHTLY SUNDAY NIGHT. HOWEVER…INVERSION LEVELS ARE
EXPECTED TO DROP SIGNIFICANTLY. SO…SNOW SHOWERS MAY BE ONGOING
ACROSS THE EXTREME WESTERN MOHAWK/SCHOHARIE VALLEY EARLY
SUNDAY…BEFORE GRADUALLY LIFTING NORTHWARD AND WEAKENING DURING
THE AFTERNOON/EVENING. ADDITIONAL MINOR ACCUMS COULD OCCUR IN
THESE AREAS…ESP IN THE MORNING. SOME FLURRIES MAY EVEN EXTEND
EAST INTO VALLEY REGIONS…ESP NORTH OF ALBANY SUNDAY AFTERNOON.
OTHERWISE…EXPECT QUITE A BIT OF CLOUDS TO REDEVELOP ACROSS
CENTRAL AND NORTHERN AREAS SUNDAY AFTERNOON AS MOISTURE BECOMES
TRAPPED BENEATH LOWERING INVERSION LEVELS. FOR MAX
TEMPS…GENERALLY SIDED CLOSER TO THE SLIGHTLY COOLER MAV MOS. FOR
SUN NT…EXPECT SOME FLURRIES/SNOW SHOWERS ACROSS THE EXTREME
WESTERN ADIRONDACKS…OTHERWISE EXPECT CLEAR TO PARTLY CLOUDY
SKIES…WITH MINS FALLING INTO THE TEENS TO LOWER 20S.

MONDAY…AT THIS TIME…LOOKS MOSTLY SUNNY AND SEASONABLY
CHILLY…WITH MAX TEMPS MAINLY IN THE LOWER/MID 30S IN
VALLEYS…AND 20S TO LOWER 30S ACROSS HIGHER ELEVATIONS. SOME
HIGH/MID LEVEL CLOUDS MAY INCREASE ACROSS SOUTHERN AREAS BY LATE
AFTERNOON.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/…
A VERY ACTIVE WEATHER PATTERN IS EXPECTED DURING THE LONG TERM
PERIOD.

CHRISTMAS EVE INTO CHRISTMAS DAY…A QUICK MOVING AREA OF LOW
PRESSURE WILL SPREAD SNOW ACROSS AT LEAST THE SOUTHERN HALF OF THE
FA MONDAY NIGHT INTO EARLY TUESDAY AS IT MOVES FROM THE MID ATLANTIC
REGION OFF THE NEW JERSEY COAST MONDAY NIGHT AND PASSES WELL
SOUTHEAST OF CAPE COD TUESDAY MORNING. THE BIG QUESTION WILL BE HOW
FAR NORTH THE PRECIPITATION SHIELD EXTENDS ESPECIALLY WITH HIGH
PRESSURE ANCHORED JUST NORTH OF THE CANADIAN BORDER. FOR NOW HAVE
HIGH CHANCE POPS SOUTH TAPERING TO LITTLE IF ANY SNOW NORTHWEST. QPF
WILL BE LIMITED WITH THIS SYSTEM AS IT WILL HAVE LITTLE TIME TO TAP
ATLANTIC MOISTURE. STILL THERE MAY BE A FEW INCHES OF SNOW ACROSS
SOUTHERN AREAS MONDAY NIGHT INTO TUESDAY MORNING WITH ANY LINGERING
SNOW TAPERING OFF DURING TUESDAY AFTERNOON. EXPECT LOWS MONDAY NIGHT
TO RANGE FROM THE MID SINGLE DIGITS NORTHWEST TO THE MID 20S
SOUTHEAST WITH HIGHS ON TUESDAY RANGING FROM THE MID 20S NORTHWEST
TO MID 30S SOUTHEAST.

TUESDAY NIGHT THROUGH WEDNESDAY MORNING…EXPECT A BRIEF BREAK IN
THE PCPN AS HIGH PRESSURE BRIEFLY BUILDS BACK INTO THE FA FROM
SOUTHERN QUEBEC. EXPECT LOWS TUESDAY NIGHT TO RANGE FROM THE MID
SINGLE DIGITS NORTHWEST TO LOWER 20S SOUTHEAST.

WEDNESDAY AFTERNOON THROUGH THURSDAY…A MUCH LARGER STORM IS
EXPECTED TO IMPACT THE FA AS IT TRACKS FROM THE GULF COAST STATES
TUESDAY NIGHT INTO THE TENNESSEE VALLEY AND CAROLINAS ON WEDNESDAY
AFTERNOON AND TO THE MIDDLE ATLANTIC COAST WEDNESDAY EVENING. THE
GFS AT THIS POINT THEN RAPIDLY LIFTS THE LOW NORTHEAST TO THE GULF
OF MAINE BY EARLY THURSDAY MORNING WHILE THE GGEM AND ECMWF SLOW THE
SYSTEM TO A CRAWL WITH THE LOW CENTER REMAINING ACROSS OR JUST OF THE
NJ COAST INTO THURSDAY MORNING BEFORE LIFTING NORTHEAST. WILL START
TO INCREASE POPS ON WEDNESDAY AFTERNOON WITH BEST CHANCE OF SNOW
WEDNESDAY NIGHT INTO THURSDAY. DUE TO THE SIZABLE NATURE OF THIS
STORM WILL INCLUDE IN HOW AT THIS POINT IN TIME. EXPECT HIGHS ON
WEDNESDAY IN THE MID 20S TO MID 30S WITH LOWS WEDNESDAY NIGHT IN THE
MID TEENS TO MID 20S AND HIGHS ON THURSDAY IN THE UPPER TEENS TO
LOWER 30S.

THURSDAY NIGHT AND FRIDAY…SNOW MAY LINGER INTO THURSDAY EVENING
ESPECIALLY ACROSS NORTHEAST PORTION OF FA WITH ANY SNOW ON FRIDAY
EXPECTED TO BE MAINLY LAKE EFFECT ACROSS THE WESTERN ADIRONDACKS.
EXPECT LOWS THURSDAY NIGHT IN THE UPPER SINGLE DIGITS TO AROUND 20
WITH HIGHS ON FRIDAY IN THE MID TEENS TO AROUND 30.

OVERALL EXPECT TEMPERATURES TO BE BELOW NORMAL WITH PRECIPITATION
ABOVE NORMAL DURING THE LONG TERM PERIOD.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/…
VFR/MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE END OF
THE TAF PERIOD ENDING AT 12Z SUNDAY…EXCEPT AT KPSF WHERE MORE
PERSISTENT UPSLOPE SNOW SHOWERS WILL LIKELY RESULT IN IFR/MVFR
CONDITIONS INTO EARLY THIS AFTERNOON.

A STRONG CYCLONIC FLOW OF AIR WILL REMAIN ACRS THE TAF SITES ALONG
WITH A STRONG PRESSURE GRADIENT IN PLACE. AS THE CYCLONIC FLOW MOVES
OVER THE GREAT LAKES IT WILL PICK UP MOISTURE RESULTING IN PLENTY OF
CLOUDS AND SCATTERED FLURRIES AND PERHAPS A BRIEF SNOW SHOWER AT THE
TAF SITES. WHILE DOWNSLOPING WILL LIMIT THE IMPACT OF THE SNOW
SHOWERS IN THE HUDSON VALLEY…MORE PERSIST UPSLOPE SNOW SHOWERS ARE
POSSIBLE AT KPSF. CONDITIONS WILL IMPROVE THIS EVENING AS THE CLOUDS
START TO GRADUALLY BREAK UP WITH SCT-BKN035-040 EXPECTED AT MOST
SITES AFT 03Z-04Z…AND SKC-SCT035 AFT 07Z.

IT WILL BE VERY WINDY AT THE TAF SITES WITH WEST TO NORTHWEST WINDS
INCREASING TO 15 TO 25 KTS WITH GUSTS 30-36 KTS THIS AFTERNOON. A
FEW GUSTS OVER 40 KTS ARE PSBL AT ALB DUE TO CHANNELED FLOW DOWN THE
MOHAWK VALLEY. THE WINDS WILL THEN GRADUALLY DIMINISH LATE THIS
EVENING.

OUTLOOK…
SAT NT-SUN…MAINLY VFR. CHC MVFR -SHSNS AT KPSF. WINDY.
SUN NT-MON…VFR. NO SIG WX.
MON NT-TUE…MVFR/IFR. CHC -SN.
TUE NT-WED AM. VFR. NO SIG WX.
WED PM…MVFR/IFR. CHC -SN.

&&

.HYDROLOGY…
MOST RIVER LEVELS HAVE CRESTED…AND ARE NOW FALLING.

THE PREDOMINANT PTYPE WILL BE SNOW OVER THE NEXT 5 DAYS. THE
STACKED LOW PRESSURE SYSTEM OVER SRN QUEBEC…AND NRN NY WILL
PRODUCE UPSLOPE SNOW ALONG THE WRN SPINE OF THE
ADIRONDACKS…GREENS…TACONICS AND BERKSHIRES. TOTAL LIQUID
EQUIVALENT AMOUNTS WILL RANGE FROM A FEW HUNDREDTHS TO A FEW
TENTHS OF AN INCH. LIGHT TO MODERATE SNOW AMOUNTS WILL BE POSSIBLE
THIS EVENING.

SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
TONIGHT THRU SUNDAY WEST OF THE HUDSON RIVER VALLEY WITH LESS THAN
A TENTH OF AN INCH OF QPF.

A BRIEF PERIOD OF DRY WEATHER IS EXPECTED SUNDAY NIGHT THROUGH
MONDAY…BEFORE A LOW PRESSURE SYSTEM POSSIBLY BRINGS SOME LIGHT
SNOW TO THE REGION MONDAY NIGHT THROUGH TUESDAY. ANOTHER MORE
POTENT SYSTEM MAY IMPACT THE HYDRO SERVICE AREA DURING THE MID
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…WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR CTZ001-013.
NY…WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ032-
033-038.
MA…WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MAZ001-025.
WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR MAZ001-025.
VT…WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR VTZ013>015.
WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR VTZ013-014.

&&

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

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