January 14, 2012 Forecast Discussion

000
FXUS61 KALY 141803
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
103 PM EST SAT JAN 14 2012

.SYNOPSIS…
COLDER AIR WILL BE USHERED IN A BRISK WESTERLY WINDS IN THE WAKE
OF AN ARCTIC BOUNDARY TODAY. HIGH PRESSURE WILL BUILD IN BEHIND
THIS FRONT FROM SOUTHEASTERN ONTARIO FOR TONIGHT INTO SUNDAY
NIGHT…WITH SUBSIDING WINDS…BUT FRIGID TEMPERATURES. THE HIGH
WILL MOVE OFF THE EAST COAST MONDAY…AS A LOW PRESSURE SYSTEM
APPROACHES FROM THE WEST…ALLOWING CLOUDS TO INCREASE MONDAY
AFTERNOON…WITH THE POSSIBILITY OF LIGHT SNOW OR A WINTRY MIX
CHANGING TO RAIN MONDAY NIGHT AND TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 830 AM…UPDATED TO EXPAND ON THE COVERAGE AND TIMING OF
THE LIKELY POPS THROUGH THIS MORNING ACROSS THE NORTHERN/CENTRAL
TACONICS…SOUTHERN GREEN MOUNTAINS AND BERKSHIRES. UPSLOPE SNOWS
CONTINUE ALONG WITH SEEDER FEEDER PROCESS WHICH CAN SEEN ON THE IR
SATELLITE…ENHANCED CLOUD TOPS. MINOR ADJUSTMENTS MADE TO
TEMPERATURES AND DEW POINTS BASED ON OBSERVATIONAL DATA. WITH COLD
AIR ADVECTION OCCURRING IN WAKE OF THE ARCTIC BOUNDARY WILL NOT SEE
MUCH CHANGE IN TEMPERATURES TODAY…WITH TEMPERATURES DROPPING OFF
RAPIDLY AFTER SUNSET. CHANCES FOR SNOW SHOWERS AND CLOUD COVER WILL
DECREASE THIS AFTERNOON AS HIGHER PRESSURE BEGINS TO BUILD IN AT THE
SURFACE AND HEIGHTS BEGIN TO RISE.

AS OF 635 AM EST…THE COMBINATION OF LOW LEVEL CONVERGENCE WITH
AND AHEAD OF ARCTIC FRONT…OROGRAPHIC LIFT…AND SEEDER FEEDER
PROCESSES FROM MID LEVEL CLOUDS ONTO A LOWER STRATUS DECK HAS
ALLOWED FOR SNOW SHOWERS AND FLURRIES TO BECOME MORE NUMEROUS OVER
THE PAST 1-2 HOURS. ENHANCEMENT OF SNOW SHOWERS SEEMS TO BE MOST
PREVALENT ACROSS THE NORTHERN TACONICS…AND SOUTHERN
GREENS…WHERE LATEST RADAR INDICATES 25-30 DBZ RETURNS. BASED ON
THIS…HAVE BOOSTED POPS INTO THE LIKELY RANGE ACROSS THIS
REGION…WITH 1-3 INCHES OF ADDITIONAL SNOWFALL ACCUM POSSIBLE
THROUGH MID MORNING. THIS AREA OF ENHANCED SNOW SHOWERS SHOULD
SINK SOUTHWARD INTO THE BERKSHIRES AS WELL…SO HAVE EXPANDED
LIKELY AND HIGH CHC POPS HERE AS WELL…WITH AT LEAST AN
ADDITIONAL INCH OR TWO OF ACCUM EXPECTED.

ELSEWHERE…HAVE ALSO INCREASED POPS BASED ON LATEST RADAR AND IR
SATELLITE…WHICH INDICATES COOLING CLOUD TOPS ACROSS THE REGION.
THESE SNOW SHOWERS AND FLURRIES COULD PRODUCE SEVERAL TENTHS OF AN
INCH OF ACCUM WHERE THEY PERSIST…WHICH SEEMS TO BE MAINLY S AND
E OF THE CAPITAL REGION.

SOME FLURRIES MAY EVEN REACH PORTIONS OF THE MID HUDSON VALLEY AND
NW CT…AND HAVE ADDED SLIGHT CHC FOR SNOW SHOWERS…OR CHC
FLURRIES HERE AS WELL. SOME PORTIONS OF THE LITCHFIELD HILLS COULD
RECEIVE SEVERAL TENTHS OF AN INCH OF SNOWFALL…IF NOT MORE…WITH
EVEN SCATTERED DUSTINGS POSSIBLE IN LOWER ELEVATIONS THROUGH MIDDAY.

AS FOR TEMPS…EXPECT THEM TO CONTINUE TRENDING DOWNWARD THROUGH
MID MORNING…BEFORE LEVELING OFF OR EVEN RISING A FEW DEGREES IN
VALLEY AREAS. THE ONE EXCEPTION COULD BE THE MID HUDSON
VALLEY…WHERE TEMPS COULD REACH THE LOWER/MID 30S BEFORE THE
FRONT PASSES…AND COLDER AIR MOVES IN.

PREVIOUS DISCUSSION FOLLOWS…

AS OF 420 AM EST…THE REMNANTS OF A LAKE EFFECT SNOW BAND ARE
APPROACHING THE CAPITAL REGION FROM THE NW…AND SHOULD MOVE
ACROSS WITHIN THE NEXT HOUR. A BURST OF LIGHT/MODERATE SNOW SHOULD
ACCOMPANY THIS…PRODUCING A DUSTING TO A FEW TENTHS OF AN INCH OF
ACCUMULATION. THESE SNOW SHOWERS MAY ALSO REACH THE TACONICS…AND
BERKSHIRES BETWEEN 5 AND 7 AM…AND COULD PRODUCE ANOTHER QUICK
COATING TO UP TO ONE INCH OF SNOW.

THE ARCTIC FRONT IS LOCATED ACROSS CENTRAL NYS…AND HEADING SE.
THIS SHOULD MOVE ACROSS NORTHERN PORTIONS OF THE REGION THROUGH
DAYBREAK…THE CAPITAL REGION SHORTLY AFTER DAYBREAK…AND FURTHER
S INTO THE MID HUDSON VALLEY AND NW CT BY MID TO LATE MORNING.
EXPECT SOME FLURRIES…OR LIGHT SNOW SHOWERS TO ACCOMPANY OR
IMMEDIATELY PRECEDE THIS BOUNDARY…PRODUCING AN ADDITIONAL
DUSTING IN SOME AREAS.

BEHIND THE FRONT…WINDS WILL INCREASE ONCE AGAIN…ALBEIT NOT
QUITE AS STRONG AS FRIDAY…AND WILL VEER INTO THE NW. THIS
VEERING FLOW…ALONG WITH A LOWERING SUBSIDENCE INVERSION…SHOULD
SQUELCH THE LAKE EFFECT ACTIVITY…WITH ANY LINGERING MULTIBANDS
PERHAPS AFFECTING THE EASTERN CATSKILLS AND SCHOHARIE VALLEY
REGION THROUGH EARLY AFTERNOON…PRODUCING MINOR ACCUMS OF AN INCH
OR LESS.

COLDER AIR WILL FILTER INTO THE REGION BEHIND THIS FRONT.
HOWEVER…GIVEN SUCH WARM INITIAL TEMPS…STILL EXPECT MAXES TO
REACH THE LOWER/MID 20S IN VALLEY REGIONS…EXCEPT
WARMER…PERHAPS LOWER TO MID 30S IN THE MID HUDSON VALLEY WHERE
SOME ENHANCED WARMING DUE TO DOWNSLOPING WILL BE POSSIBLE.

AS FOR SKY COVER…DESPITE THE PASSAGE OF THE FRONT…A SHORTWAVE
APPROACHING FROM THE WEST WILL KEEP ABUNDANT MID LEVEL CLOUDS
ACROSS THE REGION THROUGH AT LEAST EARLY AFTERNOON. THESE CLOUDS
SHOULD GRADUALLY THIN FROM W TO E DURING THE MID TO LATE
AFTERNOON. SO…DESPITE SOME EROSION FROM THE LOWER CLOUDS THIS
MORNING…THE MID LEVEL CLOUDS WILL KEEP CONDITIONS MOSTLY CLOUDY
THROUGH A GOOD PORTION OF THE DAY. WE HAVE KEPT MENTION OF
FLURRIES IN MANY AREAS THROUGH MIDDAY…EVEN BEHIND THE FRONT…AS
SOME SEEDER-FEEDER PROCESS FROM THE MID LEVEL CLOUDS OVER THE
LOWER CLOUDS MAY KEEP FLURRIES AROUND.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/…
TONIGHT…SKIES SHOULD CLEAR OUT IN MOST AREAS
OVERNIGHT…ALTHOUGH MAY BE A BIT SLOW INITIALLY ACROSS SOUTHERN
AND WESTERN PORTIONS OF THE REGION. WITH CLEARING SKIES…AND
SOMEWHAT LIGHT WINDS…AND A SNOWPACK ACROSS AT LEAST NORTHERN
PORTIONS OF THE REGION…TEMPERATURES SHOULD FALL INTO THE SINGLE
DIGITS ABOVE AND BELOW ZERO IN MANY VALLEY LOCALES…AND INTO THE
-10 TO -20 RANGE ACROSS HIGHER ELEVATIONS ACROSS THE WESTERN
ADIRONDACKS. IN THESE AREAS…ENOUGH WIND SHOULD PERSIST TO DROP
WIND CHILLS INTO THE -20 TO -25 RANGE…THEREFORE WIND CHILL
ADVISORIES HAVE BEEN HOISTED FOR THESE AREAS. THE ONLY OTHER
CAVEAT TO WATCH FOR WILL BE ANY CLOUDS AND/OR SNOW
SHOWERS/FLURRIES OFF LAKE CHAMPLAIN ACROSS PORTIONS OF THE UPPER
HUDSON VALLEY AND SW VT. CURRENT LOW LEVEL WIND TRAJECTORIES ARE
FROM THE NNW…WHICH COULD ALLOW AT LEAST SOME CLOUDS/FLURRIES TO
REACH NORTHERN WASHINGTON CO AND PORTIONS OF BENNINGTON CO VT.
TRENDS FOR THIS WILL NEED TO BE WATCHED.

SUNDAY-SUNDAY NIGHT…A RIDGE OF HIGH PRESSURE WILL SLOWLY MOVE
E…CRESTING OVER THE REGION SUNDAY EVENING BEFORE DRIFTING E OF
THE REGION LATE SUNDAY NIGHT. THIS SHOULD ALLOW FOR MOSTLY SUNNY
SKIES SUNDAY…WITH LIGHTER WINDS THAN RECENT DAYS.
HOWEVER…DESPITE MORE SUNSHINE AND LESS WIND…IT WILL BE QUITE
COLD…WITH MAX TEMPS GENERALLY ONLY REACHING 15-20 ACROSS MUCH OF
THE HUDSON RIVER VALLEY…EXCEPT FOR LOWER/MID 20S IN THE MID
HUDSON VALLEY…WITH MANY HIGHER ELEVATIONS WITHIN THE NORTH
COUNTRY AND WESTERN NEW ENGLAND ONLY REACHING THE SINGLE DIGITS OR
LOWER TEENS. TEMPS WILL FALL RAPIDLY SUNDAY NIGHT…ALTHOUGH SOME
CLOUDS MAY REACH THE REGION LATE. IF THE CLOUDS HOLD OFF…SUN NT
COULD BE EVEN COLDER THAN SAT NT/SUN AM IN SOME AREAS.
HOWEVER…AT THIS TIME…WILL ASSUME SOME CLOUDS…AND A LIGHT
SOUTH WIND DEVELOPING LATE WILL KEEP TEMPS A SHADE
WARMER…GENERALLY IN THE ZERO TO 10 ABOVE RANGE IN VALLEY
REGIONS…AND ZERO TO 10 BELOW ACROSS THE NORTH COUNTRY AND HIGHER
ELEVATIONS IN WESTERN NEW ENGLAND.

MONDAY…AS THE HIGH MOVES OFF TO THE EAST…WARM ADVECTION WILL
COMMENCE. HOWEVER…MID LEVEL CLOUDS WILL LIKELY INCREASE AS
A STRONG SURGE OF MID LEVEL THETA/E ADVECTION DEVELOPS. HAVE ALSO
INCLUDED SLIGHT CHC POPS FOR SNOW SHOWERS LATE IN THE DAY ACROSS
THE WESTERN ADIRONDACKS…WHERE THE COMBINATION OF MID LEVEL WARM
ADVECTION MAY WORK IN TANDEM WITH SOME LAKE MOISTURE. HAVE KEPT
MOST OTHER AREAS DRY AT THIS TIME…ALTHOUGH…GIVEN THE STRENGTH
OF MID LEVEL WARM ADVECTION…CAN NOT COMPLETELY RULE OUT SOME
SNOW SHOWERS DEVELOPING ELSEWHERE PRIOR TO SUNSET. AS FOR
TEMPS…GENERALLY SIDED CLOSE TO THE MAV MOS IN MOST AREAS…WITH
UPPER 20S TO LOWER 30S IN MOST VALLEYS…AND MAINLY 20S ACROSS
HIGHER ELEVATIONS.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/…
AN ACTIVE WEEK IS SHAPING UP FOR THE REGION WITH THE INITIAL WAVE
IMPACTING THE REGION DURING THE START OF THE WEEK TO BE FOLLOWED BY
A SERIES OF WAVES WITHIN THE POLAR JET ACROSS THE NORTHERN CONUS.

AS WE BEGIN THE LONG TERM PERIOD…A SHORT WAVE WILL EJECT OUT ONTO
THE CENTRAL PLAINS WITH LEE CYCLOGENESIS EVOLVING MONDAY NIGHT. DUE
TO >100KT JET…THIS WAVE WILL QUICKLY TRACK EAST-NORTHEAST AND
INTERACT WITH THE NORTHERN STREAM DURING TUESDAY. MEANWHILE…LARGE
SURFACE HIGH SLIDES OFF THE MID ATLANTIC COAST AND ITS RETURN FLOW
WILL BRING WARMER AND MOIST AIR FROM THE GULF OF MEXICO INTO THE
OHIO VALLEY. CLOUDS WILL QUICKLY INCREASE WITH PRECIP POTENTIAL
INCREASING THROUGH TUESDAY. BASED ON FORECAST SURFACE TEMPERATURES
AND PARTIAL THICKNESS SCHEMES FROM THE GLOBAL MODELS…A WINTRY
MIXTURE OF SNOW/SLEET/FZRA TRANSITIONING TO RAIN FROM SOUTH TO NORTH
THROUGH THE DAY. HOWEVER…PORTIONS OF THE DACKS AND LAKE GEORGE
REGION INCLUDING PORTIONS OF SOUTHERN VT COULD SEE THE COLD AIR
LOCKED IN LONGER FOR A PROLONGED PERIOD OF WINTRY MIXTURE.

SURFACE PRESSURES CONTINUE TO DROP AS THE DEEPENING SURFACE LOW IS
EXPECTED TO TRACK ACROSS THE ST LAWRENCE VALLEY TUESDAY NIGHT INTO
WEDNESDAY MORNING. COLD ADVECTION WILL PURSUE AS THIS WILL USHER IN
ANOTHER ROUND OF MODIFIED ARCTIC AIR FOR THE MID WEEK PERIOD. A
FAST MOVING CLIPPER APPROACHES THE GREAT LAKES REGION ON THURSDAY.
THIS MAY BRING A ROUND OF LIGHT SNOW OR SNOW SHOWERS TO THE MOST OF
THE REGION. THE EXCEPTION MAYBE THE MID HUDSON VALLEY INTO NW CT
WHERE FAVORABLE DOWNSLOPING MAY PROHIBIT SNOWFALL.

THEN A BRIEF BREAK IS EXPECTED FOR THE END OF THE WEEK BEFORE
ANOTHER SYSTEM APPROACHES FOR NEXT WEEKEND.

TEMPERATURES FOR THE UPCOMING WEEK ARE EXPECTED TO AVERAGE NEAR TO
BELOW NORMAL WITH PRECIPITATION AMOUNTS ABOVE NORMAL.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/…
VFR CONDITIONS THROUGH TAF PERIOD…18Z/SUNDAY. HIGH PRESSURE WILL
BUILD IN AT THE SURFACE WITH HEIGHTS RISING ALOFT AS UPPER TROUGH
AXIS MOVES OFF TO THE EAST AND RIDGING BUILDS IN. WILL CONTINUE TO
HAVE SOME LOW LEVEL…SCT035…LAKE EFFECT CLOUDS AT KALB AND
KPOU IN THE WEST-NORTHWESTERLY FLOW. GENERALLY CLOUD COVER WILL
BE ON THE DECREASE THIS EVENING…HOWEVER WILL HAVE SOME HIGH
CIRRUS CLOUDS MOVING OVERHEAD. CLEAR SKIES ARE EXPECTED TO DEVELOP
OVERNIGHT AND PERSIST ON SUNDAY.

AT KALB AND KPOU GUSTY WEST-NORTHWESTERLY WINDS WILL CONTINUE THIS
AFTERNOON…WEAKENING LATER THIS AFTERNOON INTO THE EVENING. A
NORTHWEST WIND PERSIST TONIGHT WITH GUSTINESS DEVELOPING AT KALB
SUNDAY MORNING. AT KGFL…A NORTHERLY WINDS WILL SHIFT TO THE
NORTHWEST THIS AFTERNOON WITH A LIGHT AND VARIABLE WIND DEVELOPING
THIS EVENING. EXPECT A LIGHT NORTHERLY WIND TO DEVELOP SUNDAY
MORNING.

OUTLOOK…
SUN NIGHT-SUN…VFR. NO SIG WX.
MON NIGHT…LOWERING. CHC SNOW WITH A WINTRY MIX POSSIBLE AT KPOU.
TUE…MVFR/IFR. PCPN LIKELY WITH A WINTRY MIX CHANGING TO RAIN.
TUE NIGHT…MVFR WITH IFR POSSIBLE. CHC OF WINTRY MIX OF PCPN.
WED-THU…VFR. NO SIG WX.

&&

.HYDROLOGY…
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT
5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS…LAKES…AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL BY
TUESDAY.

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…WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR NYZ032-033-082.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…IAA/KL/NAS/WASULA
NEAR TERM…IAA/KL
SHORT TERM…KL
LONG TERM…BGM
AVIATION…IAA
HYDROLOGY…KL/WASULA

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