January 17, 2012 Forecast Discussion

000
FXUS61 KALY 171132
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
632 AM EST TUE JAN 17 2012

.SYNOPSIS…
LOW PRESSURE WILL TRACK TOWARD THE GREAT LAKES TODAY…AND ACROSS
THE SAINT LAWRENCE RIVER VALLEY TONIGHT INTO WEDNESDAY. LIGHT
MIXED PRECIPITATION WILL TRANSITION TO RAIN BY LATE MORNING INTO
THE EARLY AFTERNOON…AS THE WARM FRONT SLOWLY MOVES NORTH OF THE
REGION. THE COLD FRONT WITH THE SYSTEM WILL QUICKLY MOVE ACROSS
EASTERN NEW YORK AND WESTERN NEW ENGLAND TONIGHT…WITH SCATTERED
SNOW SHOWERS…BLUSTERY…AND COLD CONDITIONS FOR WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 620 AM EST…HAVE UPDATED FORECAST TO REFLECT CURRENT LULL
IN PRECIP. HOWEVER…LATEST REGIONAL RADARS DEPICT AREAS OF
FREEZING DRIZZLE/DRIZZLE DEVELOPING…AND WILL WORD ACCORDINGLY
FOR AREAS SOUTH OF THE ADIRONDACKS. ACROSS THE SOUTHERN
ADIRONDACKS…OCCASIONAL LIGHT PRECIP REMAINS…SOME OF WHICH IS
SNOW…SO WILL RETAIN MIXED WORDING THERE.

ANOTHER AREA OF PRECIP HAS DEVELOPED ACROSS WESTERN NYS…POISED
TO REACH THE SOUTHERN ADIRONDACKS AROUND 9-10 AM. SOME OF THIS MAY
EXTEND FURTHER SOUTH…INTO THE MOHAWK RIVER VALLEY AND SOUTHERN
VT AS WELL. 12Z/KALY SOUNDING WILL BE CRUCIAL IN DETERMINING
P-TYPE FOR THIS AREA…WHICH…CURRENTLY LOOKS TO BE A MIX OF
SNOW/SLEET CHANGING TO FREEZING RAIN.

PREVIOUS DISCUSSION FOLLOWS…

AS OF 515 AM EST…MOST OF THE STEADIER PRECIP HAS BEEN SHUNTED
NORTHWARD…ACROSS THE SOUTHERN BERKSHIRES…WHILE ONLY PATCHY
FREEZING DRIZZLE/DRIZZLE/SNOW GRAINS REMAIN. LOW LEVEL ISENTROPIC
LIFT SHOULD ALLOW LIGHT FREEZING RAIN OR FREEZING DRIZZLE TO
PERSIST OVER THE NEXT FEW HOURS…AND GIVEN ROAD SURFACES WELL
BELOW FREEZING…WILL KEEP WINTER WEATHER ADVISORY
ONGOING…DESPITE THE LACK OF STEADIER/HEAVIER PRECIP.

STEADIER PRECIPITATION WILL REDEVELOP FROM SW TO NE THIS
AFTERNOON…AS A STRONGER SURGE OF LOW/MID LEVEL WARM ADVECTION
APPROACHES. THERMAL PROFILES SUGGEST MOST AREAS FROM ALBANY SOUTH
IN THE VALLEYS SHOULD BE PLAIN RAIN WHEN THIS ARRIVES.
HOWEVER…FOR AREAS N OF THE MOHAWK RIVER VALLEY…INTO SOUTHERN
VT…AT LEAST SOME POCKETS OF SUBFREEZING TEMPS WILL REMAIN. WILL
THEREFORE KEEP WINTER WX ADV FOR NORTHERN AREAS THROUGH EARLY
AFTERNOON. IN FACT…WOULD NOT BE COMPLETELY SURPRISED IF THE
WINTER WX ADV NEEDS TO BE EXTENDED IN TIME FOR AT LEAST SOME
AREAS…AS COLD LOW LEVEL AIR MAY BE TOUGH TO DISLODGE…ESP
ACROSS THE SOUTHERN ADIRONDACKS.

ELSEWHERE…EXPECT PERIODS OF RAIN THIS AFTERNOON…SOME OF WHICH
COULD BE MODERATE AT TIMES.

MAX TEMPS SHOULD BE REACHED CLOSE TO OR AFTER 7 PM…GENERALLY
FOLLOWED A MAV/MET MOS BLEND.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/…
TONIGHT…WARMER AIR SHOULD SURGE INTO THE REGION JUST AHEAD OF
COLD FRONT. THIS SHOULD ALLOW ALL AREAS TO RECEIVE RAIN SHOWERS.
SOME WEAK ELEVATED INSTABILITY APPROACHES THE REGION JUST AHEAD OF
THE FRONT…SO WOULD NOT BE COMPLETELY SURPRISED IF AN ISOLATED
TSTMS OCCURRED. THEN…STRONG WINDS WILL BRING COLDER AIR BACK
INTO THE REGION AFTER MIDNIGHT. BUFKIT PROFILES INDICATE STRONG
WIND POTENTIAL…ESP WITHIN THE MOHAWK RIVER
VALLEY…BERKSHIRES…CAPITAL REGION AND EASTERN CATSKILLS…WITH
GUSTS OF 50-55 MPH POSSIBLE. HAVE HOISTED A WIND ADVISORY FOR THIS
POTENTIAL IN AREAS WHERE GREATEST THREAT EXISTS. LAKE
EFFECT/UPSLOPE SNOW WILL DEVELOP ACROSS THE WESTERN ADIRONDACKS
TOWARD DAYBREAK…WITH 1-3 INCHES POSSIBLE.

WED…MAIN STORY WILL BE STRONG WINDS ONGOING THROUGH EARLY
AFTERNOON…WITH GUSTS OF 50-55 MOH POSSIBLE. SNOW
SHOWERS/FLURRIES WILL INCREASE IN AREAL COVERAGE IN THE
MORNING…WITH UPSLOPE/LAKE EFFECT SNOWS POSSIBLE. LOW LEVEL WIND
FLOW INDICATES BEST POTENTIAL ACROSS SOUTHERN HERKIMER CO…FOR
NOW DID NOT ISSUE ANY ADVISORIES…BUT THIS WILL NEED TO BE
WATCHED. ALSO…UPSLOPE SNOW ACROSS THE TACONICS/BERKSHIRES AND
GREENS COULD REACH 2-4 INCHES. EXPECT TEMPS TO FALL FROM MORNING
HIGHS IN THE 20S AND 30S.

WED NT/THU…HIGH PRESSURE RIDGE SLIDES ACROSS WED NT WITH CLEAR
SKIES AND DECREASING WIND. HAVE FOLLOWED CLOSE TO MAV MOS FOR MINS
AND MAXES. THU…EXPECT INCREASING CLOUDS AS NEXT CLIPPER TYPE
SYSTEM APPROACHES FROM THE W. SOME LIGHT SNOW COULD REACH WESTERN
AREAS BY LATE AFTERNOON.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/…
BROAD CYCLONIC UPPER FLOW DOMINATES THE REGION THROUGH THE FIRST
PART OF THE WEEKEND. THEN…UPPER RIDGING BUILDS INTO THE
SOUTHEASTERN U.S. THE SECOND PART OF THE WEEKEND INTO THE BEGINNING
OF NEXT WEEK.

ONE NORTHERN STREAM UPPER IMPULSE TRACKS THROUGH THE GREAT LAKES
THURSDAY NIGHT AND EARLY FRIDAY THAT WILL PICK UP SOME GREAT LAKES
MOISTURE BUT NOT MUCH ELSE. STILL..THERE SHOULD BE ENOUGH UPPER
ENERGY…MOISTURE AND ISENTROPIC LIFT TO PRODUCE SNOW SHOWER
ACTIVITY…WITH SOME LIGHT ACCUMULATIONS IN MANY AREAS. LOWS
THURSDAY NIGHT IN THE TEENS…SINGLE NUMBERS IN THE SOUTHERN
ADIRONDACKS. HIGHS FRIDAY IN THE 20S…TEENS IN THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS. A QUICK SHOT OF COLDER AIR
SHOULD BUILD IN BEHIND THIS SYSTEM FOR FRIDAY NIGHT…THEN WARM
ADVECTION COULD BEGIN AS SOON AS SATURDAY WITH SOME SCATTERED SNOW
SHOWERS POSSIBLE.

AFTER SATURDAY THERE IS LOTS OF SPREAD IN THE DETERMINISTIC AND
ENSEMBLE GUIDANCE AS TO THE TIMING AND STRENGTH OF SMALL UPPER
IMPULSES THAT TRACK NEAR THE REGION…AS THE UPPER RIDGING BUILDS
INTO THE EASTERN U.S. SO…GRADUAL WARMING SUNDAY AND MONDAY…WITH
SMALL CHANCES FOR SNOW SHOWERS DURING THE TIME WINDOW WHEN THE
STRONGEST WARM ADVECTION IS POSSIBLE SOME TIME SATURDAY OR SATURDAY
NIGHT. STILL…FOR SUNDAY AND MONDAY……KEEPING DRY UNTIL MORE
CONFIDENCE IN POTENTIAL TIME WINDOWS THAT MAY HAVE A CHANCE OF
PRECIPITATION. JUST GOING WITH PERIODS OF CLOUDS AND TEMPERATURES
WARMING TO THE MID 30S TO MID 40S.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/…
MUCH OF THE PRECIPITATION HAS ENDED AND THERE ARE AREAS OF DRIZZLE
AND FREEZING DRIZZLE ACROSS THE REGION. THE TEMPERATURES ARE BELOW
FREEZING AT KALB AND KGFL…BUT ABOVE FREEZING AT KPOU.
TEMPERATURES WILL RISE ABOVE FREEZING AT KALB AND KGFL LATER THIS
MORNING WHICH WILL TURN ANY LINGERING AREAS OF FREEZING DRIZZLE INTO
JUST DRIZZLE. CEILINGS SHOULD BE MOSTLY MVFR THROUGH ABOUT 17Z-18Z
WHILE VISIBILITIES SHOULD BE VFR. IN AREAS OF DRIZZLE AND FREEZING
DRIZZLE…VISIBILITIES SHOULD BE MVFR.

A MORE SOLID AREA OF RAIN IS TRACKING TOWARD THE REGION AND SHOULD
SPREAD ACROSS THE REGION THIS AFTERNOON WITH VARYING MVFR/IFR
CEILINGS AND VISIBILITIES AFTER 17Z…AND THROUGH ABOUT 03Z AT ALL
THE TAF SITES. AFTER ABOUT 03Z…THE RAIN SHOULD END AND CEILINGS
SHOULD BEGIN TO LIFT…GETTING BACK TO VFR AFTER MIDNIGHT.

SOUTH WINDS THROUGH THIS AFTERNOON AT 10 KT OR LESS WILL BECOME WEST
AND NORTHWEST AFTER MIDNIGHT AND INCREASE TOWARD 15 KT.

OUTLOOK…
TUE…MVFR/IFR…-SHRA LIKELY.
TUE NIGHT…MVFR WITH IFR POSSIBLE…CHANCE OF -SHRA/-SHSN.
WED…VFR…WINDY. SLIGHT CHC -SHSN.
WED NIGHT…VFR…NO SIG WX.
THU…MAINLY VFR…SLIGHT CHC -SHSN WITH MVFR POSSIBLE.
FRI…VFR. NO SIG WX.
SAT…VFR/MVFR CHC -SHSN.

&&

.HYDROLOGY…
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT
5 DAYS.

A LIGHT MIXED PRECIPITATION EVENT WILL CHANGE TO RAIN TODAY WITH
TOTAL QPF GENERALLY UNDER A QUARTER OF AN INCH. A COLD FRONT WILL
MOVE THROUGH THIS EVENING WITH SOME SCATTERED RAIN AND SNOW
SHOWERS WITH LIGHT LIQUID EQUIVALENT AMOUNTS WELL UNDER A QUARTER
OF AN INCH. THE HIGHEST SNOW TALLIES WILL BE ALONG THE WESTERN
SLOPES OF THE SOUTHERN ADIRONDACKS…AND THE SOUTHERN GREEN
MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY. COLD AND DRY WEATHER WILL
PREVAIL LATE WEDNESDAY THROUGH THURSDAY. A CLIPPER LOW MAY BRING
SOME LIGHT SNOW THURSDAY NIGHT INTO FRIDAY.

ICE FORMATION OR THICKENING WILL SLOW DOWN THROUGH TONIGHT WITH A BRIEF
SPELL OF MILDER WEATHER. ICE FORMATION SHOULD INCREASE AGAIN
WEDNESDAY INTO THURSDAY AS TEMPERATURES FALL BACK WELL BELOW
FREEZING.

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 WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
CTZ001-013.
NY…WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ047>054-058>061-063>066.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM EST WEDNESDAY FOR
NYZ038>040-047>054-058>061-063-082.
WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038>043-082>084.
MA…WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MAZ001-025.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM EST WEDNESDAY FOR
MAZ001-025.
VT…WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
VTZ013>015.

&&

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

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