January 29, 2013 Forecast Discussion

000
FXUS61 KALY 292142
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
442 PM EST TUE JAN 29 2013

.SYNOPSIS…
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TONIGHT…THEN LIFT
NORTH OF THE REGION WEDNESDAY…BRINGING MUCH WARMER TEMPERATURES
IN ITS WAKE. A PERIOD OF RAIN WILL BE POSSIBLE TONIGHT AS THE WARM
FRONT LIFTS NORTHWARD…WITH SOME FREEZING RAIN POSSIBLE ACROSS
NORTHERN AREAS. A STRONG COLD FRONT WILL PASS THROUGH THE AREA
WEDNESDAY NIGHT…ACCOMPANIED BY LOCALLY HEAVY RAIN SHOWERS…AND
FOLLOWED BY MUCH COLDER AND BLUSTERY CONDITIONS FOR THURSDAY AND
FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/…
AS OF 430 PM EDT…THE REMNANTS OF AN EARLIER MCV-LIKE FEATURE WAS
SLIDING EAST SOUTHEAST…INTO THE EASTERN CATSKILLS…AND WILL
THEN TRANSLATE ACROSS THE MID HUDSON VALLEY/SOUTHERN TACONICS AND
NW CT. LIGHT TO MODERATE PRECIPITATION IS OCCURRING WITH AND NORTH
OF THIS FEATURE…WITH MAINLY JUST SPRINKLES FURTHER N AND
E…INTO THE CAPITAL REGION AND BERKSHIRES. SFC TEMPS CONTINUE TO
HOVER NEAR OR BELOW FREEZING ACROSS HIGHER ELEVATIONS OF BERKSHIRE
AND LITCHFIELD COS…SO CAN NOT RULE OUT SOME POCKETS OF ICING ON
UNTREATED SURFACES AS THIS MOVES THROUGH. HAVE THEREFORE ISSUED A
FREEZING RAIN ADVISORY FOR THIS EVENING FOR ELEVATIONS ABOVE 1000
FT IN BERKSHIRE AND LITCHFIELD COS.

ACROSS THE WINTER WX ADVISORY AREA TO THE NORTH…THE FIRST PATCH
OF VERY LIGHT PRECIP HAS ALREADY MOVED THROUGH. HOWEVER…OF
GREATER CONCERN IS THE DEVELOPING PRECIP SHIELD ACROSS WESTERN NYS
AND POINTS S AND W. THIS APPEARS TO BE WITHIN LEADING EDGE OF LOW
LEVEL JET…WHICH IS REDEVELOPING FURTHER SOUTH AND WEST.
INCREASED MID LEVEL ISENTROPIC LIFT SHOULD SUPPORT A GREATER SURGE
OF PRECIP LATER THIS EVENING…INTO THE OVERNIGHT HOURS. EXPECT
OCCASIONAL FREEZING RAIN/SLEET TO OVERSPREAD THE WESTERN MOHAWK
VALLEY/SOUTHERN ADIRONDACKS AFTER 6 PM…AND INTO THE LAKE
GEORGE/SARATOGA REGION BETWEEN 7-9 PM…AND INTO SOUTHERN VT
BETWEEN 9 AND 10 PM. THIS SHOULD LAST THROUGH AROUND OR JUST AFTER
MIDNIGHT…BEFORE POTENTIALLY LIFTING FURTHER NORTH AS MID LEVEL
WINDS BACK. WILL HAVE TO WATCH THE ADVISORY AREA CLOSELY…AS SOME
ICE ACCRETION AMTS COULD APPROACH ONE QUARTER OF AN INCH IF PRECIP
PERSISTS.

IN ADDITION…STILL CAN NOT RULE OUT SOME SLEET AND/OR WET SNOW TO
BE MIXED IN AT TIMES ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS…AND PERHAPS HIGHER ELEVATIONS OF SOUTHERN VT.

FURTHER SOUTH…EXPECT A FEW PERIODS OF LIGHT TO MODERATE RAIN
THROUGH MIDNIGHT…ALTHOUGH WILL NEED TO WATCH FOR POCKETS OF
FREEZING RAIN…ESP CLOSER TO THE IMMEDIATE CAPITAL DISTRICT IF
ANY BREAKS IN THE CLOUDS OCCUR SHORTLY AFTER SUNSET.

THERE ARE SOME HINTS OF ELEVATED INSTABILITY ACROSS NORTHERN AREAS
LATER TONIGHT. SO…CAN NOT COMPLETELY RULE OUT SOME RUMBLES OF
THUNDER WITHIN AREAS OF RAIN ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS.

FOR TEMPS…HAVE GENERALLY WENT WITH THE COLDER MAV MOS…WITH
UPPER 20S TO LOWER 30S ACROSS MUCH OF THE ADV AREA…WITH MID 30S
ELSEWHERE. TEMPS SHOULD SLOWLY RISE TOWARD DAYBREAK.

AREAS OF FOG WILL LIKELY DEVELOP AND THICKEN LATER TONIGHT AS THE
LOW LEVEL AIR MASS CONTINUES TO MOISTEN.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/…
WED…THE INITIAL WARM SURGE ALOFT SHOULD TRANSLATE WELL N AND E
OF THE REGION. HOWEVER…THE BOUNDARY LAYER MAY BE SLOW TO RESPOND
GIVEN SUCH A COLD/FROZEN GROUND…AND SOME LINGERING SNOW PACK. AS
ANOMALOUSLY WARM AND MOIST AIR ADVECTS NORTHWARD…AREAS OF
FOG/DRIZZLE WILL LIKELY DEVELOP…WITH SOME DENSE FOG POSSIBLE.
INCREASED FORCING AHEAD OF THE INCOMING COLD FRONT SHOULD ALLOW
FOR SHOWERS TO DEVELOP…ESP ACROSS WESTERN AREAS DURING THE LATE
MORNING INTO THE AFTERNOON HOURS. THERE IS SOME HINT OF ELEVATED
INSTABILITY…SO CAN NOT RULE OUT SOME ISOLATED RUMBLES OF
THUNDER. SHOWERS WILL BECOME MORE WIDESPREAD DURING THE MID TO
LATE AFTERNOON HOURS…WITH SOME LOCALLY HEAVY RAINFALL
POSSIBLE…ESP TOWARD AND AFTER SUNSET.

WED NT…THE STRONG COLD FRONT WILL SLOWLY MOVE E ACROSS THE
REGION BEFORE MIDNIGHT. AS THE MID/UPPER LEVEL TROUGH BECOMES
SLIGHTLY NEGATIVE TILTED…THERE IS THE POTENTIAL FOR A NARROW
COLD FRONTAL RAINBAND TO DEVELOP…WHICH WOULD GREATLY ENHANCE
RAINFALL AMTS/RATES. GIVEN A DEEP FROZEN GROUND…THIS COULD LEAD
TO HYDRO ISSUES. SEE HYDRO SECTION BELOW FOR MORE DETAILS. SOME
EMBEDDED TSTMS WILL BE POSSIBLE AS WELL. BEHIND THE INTIAL
FRONT…AN AREA OF STRATIFORM LIGHT TO MODERATE PRECIPITATION IS
LIKELY TO LINGER UNTIL ANOTHER SFC FRONT PASSES CLOSER TO
DAYBREAK THU. COOLING ALOFT COULD ALLOW SOME OF THIS TO CHANGE
BACK TO SNOW ACROSS HIGHER ELEVATIONS OF THE WESTERN
ADIRONDACKS…AND CATSKILLS…WITH MINOR ACCUMS POSSIBLE.

AS FOR WIND POTENTIAL WED THROUGH WED NT…GOOD CONSENSUS FOR
EXCEPTIONALLY STRONG SOUTH TO SOUTHWEST BOUNDARY LAYER FLOW TO
DEVELOP TOMORROW AND CONTINUE TOMORROW NIGHT AHEAD OF THE COLD
FRONT. WINDS COULD BE ABOVE 70 MPH ABOVE 5000 FEET LATE TOMORROW
AND TOMORROW NIGHT. THE QUESTION IS…HOW MUCH OF THESE STRONG
SOUTH TO SOUTHWEST WINDS WILL MIX TO THE GROUND? THE GROUND IS
QUITE COLD…AND FROZEN TO QUITE A DEPTH…AND FORECAST SOUNDINGS
FROM GUIDANCE SHOWS LESS THAN IDEAL LAPSE RATES TO FULLY MIX DOWN
WINDS ALOFT…OUTSIDE OF ANY POTENTIAL CONVECTION. IF WINDS ARE
MAINLY ASSOCIATED WITH CONVECTIVE DOWNDRAFTS…THEN IT WOULD
REQUIRE SHORT TERM WARNINGS…NOT LONG TERM WIND ADVISORIES AND
HIGH WIND WARNINGS.

IN THE HEART OF WINTER…IT IS OFTEN RARE TO GET THE FULL BOUNDARY
LAYER FLOW TO REACH THE SURFACE OUTSIDE OF THE ISOLATED HIGHEST
PEAKS IN THE EASTERN CATSKILLS…SOUTHERN ADIRONDACKS AND SOUTHERN
GREEN MOUNTAINS. THERE COULD BE MORE WIDESPREAD ADVISORY LEVEL SOUTH
TO SOUTHWEST WINDS WITHIN AREAS OF TERRAIN…AND MAYBE FUNNELING
THROUGH THE HUDSON VALLEY. NOT ENOUGH CONFIDENCE OF WIDESPREAD
EFFICIENT MIXING OF THE WINDS TO THE SURFACE TO ISSUE ANY HIGH WIND
WATCHES OR WIND ADVISORIES FOR THE WARM SOUTH TO SOUTHWEST
WINDS…FOR LATE TOMORROW AND TOMORROW NIGHT. HEADLINES MAY BE
ISSUED TONIGHT FOR ANY POTENTIAL WIND PROBLEMS LATER TOMORROW AND
TOMORROW NIGHT…ONCE THE NEXT SET OF GUIDANCE PROVIDES MORE CLUES
AND IF CONFIDENCE INCREASES.

THU…SOME LINGERING SHOWERS OF RAIN/SNOW IN THE
MORNING…OTHERWISE WINDY AND PROGRESSIVELY COLDER. LAKE EFFECT
SNOWBANDS MAY DEVELOP ACROSS NORTHERN HERKIMER CO LATE IN THE
DAY…AND COULD SHIFT SLIGHTLY SOUTHWARD INTO CENTRAL OR SOUTHERN
HERKIMER CO THU NT. ONCE THE COLD FRONT TRACKS THROUGH…THERE
COULD BE A MORE WIDESPREAD WIND ADVISORY NEEDED WITH WEST TO
NORTHWEST WINDS ASSOCIATED WITH THE STRONG COOLING ACROSS THE
REGION. THAT CAN BE ADDRESSED AFTER THE PRE FRONTAL WIND POTENTIAL
SINCE THE POTENTIALLY STRONG WINDS ASSOCIATED WITH THE COOLING
WOULD BE THURSDAY…A BIT TOO FAR IN THE FUTURE FOR HIGH ENOUGH
CONFIDENCE FOR WIND HEADLINES.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/…
MULTIPLE NORTHERN STREAM UPPER SHORT WAVES ARE PREDICTED TO TRACK
THROUGH THE CYCLONIC FLOW AROUND THE MEAN NORTH AMERICAN UPPER
TROUGH. EACH UPPER SHORT WAVE SHOULD INTERACT WITH SOME LAKE EFFECT
MOISTURE…BUT OTHER THAN THAT…EACH SYSTEM SHOULD BE RELATIVELY
MOISTURE STARVED. EACH UPPER IMPULSE SHOULD REINFORCE THE COLDER AIR
OVER THE REGION…AND ENHANCE LAKE EFFECT SNOW SHOWER ACTIVITY…
ESPECIALLY IN THE WESTERN MOHAWK VALLEY…SOUTHERN ADIRONDACKS…
SCHOHARIE VALLEY…MAYBE TO THE EASTERN CATSKILLS…DEPENDING ON HOW
WEST OR NORTHWEST THE LOW LEVEL FLOW IS.

SO…MORE CLOUDS THAN SUN IN MANY AREAS THROUGH THE PERIOD…ALONG
WITH INTERVALS OF ISOLATED TO SCATTERED SNOW SHOWERS THROUGH THE
PERIOD. AGAIN…THE BEST CHANCES FOR SNOW SHOWERS WILL BE IN CLOSEST
PROXIMITY TO LAKE ONTARIO.

BY TUESDAY..THERE ARE HINTS OF A POTENTIAL COASTAL STORM OF SOME
SORT…BUT QUITE A LOT OF SPREAD SUGGESTING THERE IS JUST AS MUCH OF
A CHANCE THAT IT WILL BE TOO FAR SOUTH AND EAST TO AFFECT OUR
FORECAST AREA. SO…JUST GOING GENERIC CHANCES FOR SNOW SHOWERS
MONDAY AND TUESDAY. THERE IS LOTS OF TIME TO WATCH FOR THE
POTENTIAL…OR NON POTENTIAL FOR THIS SYSTEM.

TEMPERATURES THROUGH THE PERIOD SHOULD BE AROUND TO A LITTLE BELOW
NORMAL. HIGHS EACH DAY IN THE 20S TO MID 30S…WITH AROUND 20
SOUTHERN ADIRONDACKS AND MID 30S MID HUDSON VALLEY AND NW CT. BY
TUESDAY WITH POTENTIAL WARM ADVECTION IN PROXIMITY TO THE POTENTIAL
COASTAL SYSTEM…HIGHS IN THE MID TO UPPER 30S MANY AREAS…MID TO
UPPER 20S SOUTHERN ADIRONDACKS.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/…
CONDITIONS WILL ONLY IMPROVE SLIGHTLY TO MVFR FOR THIS
AFTERNOON…BEFORE A FRONTAL BOUNDARY AND ASSOCIATED RAIN
DETERIORATES CONDITIONS BACK TO IFR/LIFR LEVELS.

THIS AFTERNOON…MOST TAF SITES REMAIN UNDER CLOUDY SKIES ASSOCIATED
WITH A FRONTAL BOUNDARY DRAPED ACROSS THE AREA…EXCEPT AT KPOU
WHERE A FEW BREAKS HAVE ALLOWED VISIBILITIES AND CEILINGS TO IMPROVE
TO MVFR/VFR LEVELS. GUIDANCE AND FORECAST SOUNDINGS CONTINUE TO
DEPICT VERY MOIST LOW LEVELS WHICH WILL KEEP CEILINGS GENERALLY
BELOW 3 KFT AT KALB…KPSF…AND KGFL. WINDS WILL BE LIGHT AND
VARIABLE GENERALLY LESS THAN 5 KNOTS.

TONIGHT INTO WEDNESDAY…AFOREMENTIONED FRONTAL BOUNDARY WILL BEGIN
TO SLOWLY SHIFT NORTHWARDS AHEAD OF AN APPROACHING SYSTEM FROM THE
MIDWEST. LIFT ALONG THIS FRONT WILL AID IN WIDESPREAD RAIN SHOWERS
TO OCCUR AT ALL TAF SITES THROUGH MUCH OF THE OVERNIGHT
PERIOD…WITH CEILINGS AND VISIBILITIES DETERIORATING TO IFR/LIFR BY
THE EVENING HOURS. HAVE MENTIONED THE POSSIBILITY OF -FZRA AT KGFL
DURING THE OVERNIGHT PERIOD AS WELL AS SURFACE TEMPERATURES MAY BE
COLD ENOUGH FOR A PERIOD TO ALLOW FOR ACCUMULATING ICE UP TO A
QUARTER OF AN INCH.

WINDS WILL SLOWLY INCREASE DURING THE DAY WEDNESDAY AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF A POWERFUL STORM SYSTEM. A STRONG
SOUTHWESTERLY LOW LEVEL JET WILL INTRODUCE LLWS INTO THE TAFS DURING
THE DAY WEDNESDAY AS WELL. CEILINGS AND VISIBILITIES WILL BE TRAPPED
UNDERNEATH A STRONG INVERSION…STRUGGLING TO REACH MVFR LEVELS.

OUTLOOK…
WED NIGHT…MVFR/IFR. RA LIKELY. WINDY.
THU…MAINLY VFR. CHC SUB-VFR -SHRA/-SHSN. WINDY.
FRI-SAT…MAINLY VFR. SCHC SUB-VFR -SHSN.

&&

.HYDROLOGY…
A STRONG STORM SYSTEM WILL BRING 1 TO 3 INCHES OF RAINFALL TO THE
ALBANY FORECAST AREA FROM TONIGHT INTO THURSDAY MORNING. THIS IS
EXPECTED TO BE ACCOMPANIED BY ABOVE FREEZING TEMPERATURES AND SOME
SNOW MELT. IN ADDITION…THE GROUND IS FROZEN ACROSS MOST OF THE
AREA.

THE COMBINATION OF MODERATE TO HEAVY RAIN AND SNOW MELT ON FROZEN
GROUND WILL LIKELY CAUSE LOCALIZED SMALL STREAM FLOODING. WITH SOME
ROAD CULVERTS CLOGGED WITH ICE…A FEW RURAL ROAD WASHOUTS ARE ALSO
LIKELY. PAST HISTORY SAYS THAT EVENTS LIKE THIS ALSO PRODUCE A COUPLE
OF HILLSIDE SLIPS OR MUD SLIDES IN STEEP TERRAIN. BASEMENT FLOODING
IS ALSO POSSIBLE.

SHORT LIVED RIVER ICE JAMS ARE ALSO POSSIBLE. ICE IS NOT YET THICK
ENOUGH FOR LONG LIVED ICE JAMS THAT WOULD CAUSE SERIOUS FLOODING.
SOME MINOR FLOODING IS POSSIBLE FROM ICE JAMS.

THERE IS A LOW CHANCE FOR LARGER RIVER FLOODING AT THIS TIME. NO
LARGER RIVER FLOODING IS FORECAST BY THE RIVER FORECAST CENTER.
HOWEVER…LATER FORECASTS SHOULD BE MONITORED.

TIMING…BEST CHANCE FOR FLOODING LOOKS TO BE WEDNESDAY NIGHT AND
THURSDAY.

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.

&&

.CLIMATE…
RECORD HIGHS FOR JANUARY 30TH…
ALBANY: 54 DEGREES 1974 (RECORDS DATE BACK TO 1874)
GLENS FALLS: 50 DEGREES 1974 (RECORDS DATE BACK TO 1949)
POUGHKEEPSIE: 60 DEGREES 2006 (RECORDS DATE BACK TO 1949)
BENNINGTON: 60 DEGREES 2006 (RECORDS DATE BACK TO 1998)

&&

.ALY WATCHES/WARNINGS/ADVISORIES…
CT…FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR CTZ001-013.
FREEZING RAIN ADVISORY UNTIL 10 PM EST THIS EVENING FOR CTZ001-
013.
NY…FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR NYZ032-
033-038>043-082>084.
MA…FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR MAZ001-025.
FREEZING RAIN ADVISORY UNTIL 10 PM EST THIS EVENING FOR MAZ001-
025.
VT…FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR VTZ013>015.
WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR
VTZ013>015.

&&

$$
SYNOPSIS…KL
NEAR TERM…KL
SHORT TERM…KL/NAS
LONG TERM…NAS
AVIATION…IRL/NAS
HYDROLOGY…SND
CLIMATE…ALY STAFF

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