886
FXUS61 KALY 182328
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
628 PM EST WED DEC 18 2024
SYNOPSIS
HIGH-ELEVATION, LIGHT SNOWFALL AND VALLEY RAIN WILL
OCCUR THIS AFTERNOON THROUGH TONIGHT BEFORE DRY CONDITIONS RETURN
TOMORROW. ADDITIONAL SNOWFALL COMES FRIDAY WHEN REGIONWIDE SNOW
SHOWERS ARE ANTICIPATED TO BRING LIGHT ACCUMULATIONS. DRY WEATHER
RETURNS FOR MUCH OF THE WEEKEND WITH INCREASING CONFIDENCE FOR BELOW
NORMAL TEMPERATURES.
NEAR TERM /THROUGH THURSDAY/
UPDATE
AS OF 630 PM EST, LIGHT TO MODERATE RAIN HAS
OVERSPREAD MOST AREAS ACROSS EASTERN NY/WESTERN NEW ENGLAND,
ALTHOUGH WET SNOW WAS OCCURRING MAINLY FOR ELEVATIONS ABOVE 1500
FEET ACROSS THE SW ADIRONDACKS PER LATEST NYS MESONET WEBCAMS.
RAINFALL RATES ARE GENERALLY 0.05-0.10"/HOUR, WITH SNOWFALL
RATES AROUND 0.5"/HOURS.
AREA OF RAIN WILL PERSIST ACROSS THE REGION FOR THE NEXT 3-5
HOURS, WITH A GRADUAL CHANGEOVER TO SNOW FROM NW TO SE ACROSS
HIGHER TERRAIN AREAS. VALLEY AREAS FROM ALBANY NORTH COULD SEE
SOME WET SNOW AS THE PRECIPITATION TAPERS OFF BETWEEN 10 PM AND
MIDNIGHT.
[PREVIOUS AFD]...
KEY MESSAGE: LIGHT SNOWFALL OF 1" TO 3" IS LIKELY IN THE
SOUTHWEST ADIRONDACKS AND SOUTHERN GREENS THIS AFTERNOON INTO
TONIGHT WITH A DUSTING TO 1" IN THE EASTERN CATSKILLS,
BERKSHIRES, MOHAWK VALLEY, AND UPPER-HUDSON VALLEY. TRAVEL COULD
BE SLIPPERY FOR THE MORNING COMMUTE TOMORROW MORNING ON
UNTREATED ROADWAYS IN HIGHER TERRAIN REGIONS WHOSE ELEVATION
EXCEEDS 500-1000 FT.
LATEST SCANS OF THE KENX RADAR SHOW WEAK REFLECTIVITY IN THE
SOUTHWEST ADIRONDACKS, WESTERN MOHAWK VALLEY, AND UPPER-HUDSON
VALLEY WITH NYS MESONET CAMERAS VALIDATING LIGHT SNOW AT OLD
FORGE, RAQUETTE LAKE, INDIAN LAKE, AND PISECO. WITH SUCH WEAK
RETURNS AND LIGHT RATES PER LATEST OBS, IT IS LIKELY THAT SOME
OF THE PRECIPITATION IS NOT REACHING THE GROUND AT THIS TIME.
ADDITIONAL PRECIPITATION IS ON ITS WAY, HOWEVER, WITH UPSTREAM
SCANS INDICATING REFLECTIVITY ADVANCING TOWARDS THE WESTERN
BOUNDARY OF OUR CWA. WITH TEMPERATURES NEAR OR JUST AT FREEZING
IN THE SOUTHWEST ADIRONDACKS, PRECIPITATION HERE WILL CONTINUE
AS SNOW. HOWEVER, MILD TEMPERATURES OF UPPER 30S TO LOW 40S IN
THE EASTERN CATSKILLS WILL ENSURE RAIN OR A POSSIBLE RAIN/SNOW
MIX AT THE HIGHEST ELEVATIONS, AT ONSET WITHIN THE NEXT HOUR.
LATEST SPC MESOANALYSIS AND WATER VAPOR IMAGERY INDICATE THE
EXPECTANT SHORTWAVE TROUGH CURRENTLY CUTTING THROUGH THE WESTERN
GREAT LAKES, ITS BASE SWINGING THROUGH CENTRAL MICHIGAN. AT THE
SURFACE, LOW PRESSURE HAS TRACKED INTO THE WESTERN MID-ATLANTIC,
WITH WARM AIR ADVANCING NORTHWARD INTO THE MID-HUDSON VALLEY
AHEAD OF ITS EASTWARD-EXTENDING WARM FRONT. THROUGHOUT THE
REMAINDER OF THE AFTERNOON AND INTO THIS EVENING, THE
AFOREMENTIONED SHORTWAVE WILL DIG SLIGHTLY FARTHER SOUTH AND
EAST AS THE SURFACE LOW TAKES A NORTHEASTERLY TRAJECTORY TOWARDS
THE LONG ISLAND COASTLINE. AN AREA OF STRATIFORM PRECIPITATION
WILL THEREFORE CONTINUE TO OVERSPREAD THE REGION FROM WEST TO
EAST WITH SOUTHERLY FLOW ADVECTING MOISTURE INTO THE REGION.
DESPITE THE WARM AIR ADVECTION RESULTING FROM THE NEARING OF THE
WARM FRONT, WE WILL END UP ON THE COOL SIDE OF THE SURFACE LOW
WHICH WILL PROMOTE COOLING TEMPERATURES, ESPECIALLY IN AREAS OF
HIGHER TERRAIN WHERE UPSLOPE WINDS, SWIFTLY VEERING FROM THE
SOUTH TO NORTHWEST, WILL ENHANCE LIFT AND THEREFORE DYNAMIC
COOLING. HENCE, WHILE THE EASTERN CATSKILLS MAY BEGIN AS RAIN OR
A RAIN SNOW MIX, A QUICK TRANSITION TO SNOW, ESPECIALLY AT THE
HIGHEST ELEVATIONS, WILL BE REALIZED AS WETBULBING TAKES PLACE.
WHILST THE HIGHER ELEVATIONS OF THE SOUTHWEST ADIRONDACKS,
EASTERN CATSKILLS, AND SOUTHERN GREENS RECEIVE SNOW, LARGE
VALLEY AREAS WILL SEE PLAIN RAIN THROUGHOUT MUCH OF THE DURATION
OF THE EVENT. HOWEVER, AS TEMPERATURES COOL OVERNIGHT, WET
SNOWFLAKES COULD MIX IN WITH RAIN ESPECIALLY ON THE LEEWARD SIDE
OF HIGHER TERRAIN REGIONS.
STRATIFORM PRECIPITATION LOOKS TO BECOME GREATLY REDUCED IN
SPATIAL SPREAD BY 2 AM, WITH MERE SNOW OR RAIN/SNOW SHOWERS
LEFT OVER AS THE SURFACE LOW QUICKLY TRACKS INTO COASTAL NEW
ENGLAND AND THE UPPER-LEVEL SHORTWAVE BEGINS TO FILL ACROSS THE
REGION TO THE NORTH AND WEST. SHOWERS AT THIS POINT WILL BE
LIMITED PRIMARILY TO THE SOUTHWEST ADIRONDACKS, EASTERN
CATSKILLS, AND SOUTHERN GREENS COURTESY OF LAKE ENHANCEMENT AND
UPSLOPE FLOW. SHOWERS WILL CONTINUE TO TAPER OFF THROUGH THE
MORNING, WITH JUST SCATTERED, LIGHT SHOWERS IN THE SOUTHWEST
ADIRONDACKS BY THE MORNING COMMUTE TOMORROW. WHEN ALL IS SAID
AND DONE, SNOWFALL TOTALS WILL BE GREATEST IN THE SOUTHWEST
ADIRONDACKS AND SOUTHERN GREENS WHERE GENERALLY 1" TO 3" IS
EXPECTED WITH ISOLATED POCKETS OF UP TO 4". ELSEWHERE, IN THE
WESTERN MOHAWK VALLEY; UPPER-HUDSON VALLEY; BERKSHIRES; AND
EASTERN CATSKILLS, ACCUMULATIONS WILL GENERALLY RANGE FRO A
DUSTING TO 1". QPF FOR THIS EVENT WILL BE GREATEST WITHIN THE
GREATER CAPITAL DISTRICT SOUTH AND EAST WHERE 0.25" TO ABOUT
0.5" IS EXPECTED. ELSEWHERE, ABOUT 0.15" TO 0.3" IS EXPECTED.
AND WITH THE SWIFTNESS OF THIS EVENT, MINIMAL IMPACTS ARE
EXPECTED OTHER THAN THE POSSIBILITY OF SLIPPER TRAVEL TOMORROW
MORNING ON UNTREATED ROADWAYS FOR AREAS WHOSE ELEVATION MEETS OR
EXCEEDS 1000FT.
WITH COOLER AIR ADVECTING INTO THE REGION FROM FLOW VEERING TO
THE NORTHWEST, LOW TEMPERATURES WILL FALL TO THE MID 20S TO LOW
30S.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/
LIGHT SNOW SHOWERS WILL CONTINUE IN THE SOUTHWEST ADIRONDACKS
THROUGH TOMORROW MORNING AS CYCLONIC FLOW PERSISTS ACROSS THE
REGION WITHIN THE REAR FLANK OF THE DEPARTING SHORTWAVE.
ADDITIONAL ACCUMULATIONS WILL BE MINIMAL, MAXIMIZING AT A COUPLE
TENTHS AT BEST. REGIONWIDE DRY CONDITIONS WILL BE REINFORCED BY
TOMORROW AFTERNOON AS WEAK, SHORTWAVE RIDGING BUILDS IN FROM THE
WEST AND SURFACE HIGH PRESSURE SLIDES EAST OVERHEAD FROM
SOUTHERN ONTARIO. HIGH TEMPERATURES WILL BE COOLER THAN TODAY
WITH MID/UPPER 20S TO LOW 30S ABOVE 500 FT AND MID/UPPER 30S TO
LOW 40S IN VALLEY AREAS. DRY CONDITIONS WILL THEN PERSIST INTO
THE OVERNIGHT PERIOD TOMORROW NIGHT WITH LOWS DROPPING INTO THE
MID/UPPER 10S TO MID/UPPER 20S AND POCKETS OF LOW 10S AT THE
HIGHEST PEAKS OF THE SOUTHWEST ADIRONDACKS.
WHILE CONFIDENCE IS INCREASING IN WIDESPREAD, LIGHT SNOWFALL FOR
FRIDAY, THERE REMAINS SOME UNCERTAINTY IN THE EVOLUTION OF THE
SYSTEM(S) WHICH WILL CAUSE IT. BY FRIDAY MORNING, ANOTHER
SHORTWAVE TROUGH WILL BE SETTLING INTO THE OHIO VALLEY WITH A
WEAKENING SURFACE CYCLONE DIRECTLY BENEATH. AS THE SHORTWAVE
DEEPENS AND SINKS SOUTH AND EAST, THE SURFACE LOW WILL CONTINUE
TO WEAKEN INTO A WAVE, BECOMING ABSORBED INTO THE DEEPENING LOW
OFF THE MID- ATLANTIC SHORELINE. LIGHT SNOW SHOWERS ARE
CURRENTLY PROGGED TO SPREAD INTO THE REGION FROM WEST TO
EAST AS A RESULT OF EMBEDDED SHORTWAVE PULSES WITHIN THE MAIN
TROUGH DRIVING VERTICAL ASCENT THROUGHOUT OUR REGION. AS THE
FORECAST CURRENTLY STANDS, LITTLE PRECIPITATION WILL RESULT FROM
THE COASTAL LOW UNDERGOING CYCLOGENESIS OTHER THAN POSSIBLY OUR
WESTERN NEW ENGLAND ZONES. THIS RESULTS FROM THE LACK OF PHASING
OF THE DEEPENING LOW AND THE DEEPENING SHORTWAVE TROUGH.
HOWEVER, SHOULD THE NORTHEAST TRACK OF THE COASTAL LOW END UP
BEING SLOWER THAN LATEST GUIDANCE INDICATES, PHASING OF THIS
WITH THE SHORTWAVE COULD RESULT IN ADDITIONAL, AND POTENTIAL
ENHANCEMENT OF, PRECIPITATION ACROSS THE REGION. EITHER WAY,
WITH A COLD ANTECEDENT AIRMASS AND OUR POSITION RELATIVE TO THE
LOW, ALL PRECIPITATION WILL BE SNOW. AS THE CURRENT FORECAST
STANDS, WIDESPREAD ACCUMULATIONS OF 1" TO 3" ARE POSSIBLE
THROUGH SATURDAY.
HIGH TEMPERATURES FRIDAY WILL RANGE FROM THE MID 20S TO LOW 30S
WITH POCKETS OF LOW 20S IN THE HIGHEST PEAKS OF THE SOUTHWEST
ADIRONDACKS AND MID 30S IN THE MID-HUDSON VALLEY. LOW
TEMPERATURES FRIDAY NIGHT WILL THEN DROP INTO THE LOW/UPPER 10S
TO LOW/MID 20S.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
SNOW SHOWERS WILL CONTINUE INTO SATURDAY AS UNSETTLED MID AND
UPPER-LEVELS LEAD TO THE ROTATION OF ADDITIONAL SHORTWAVES
THROUGH THE REGION. AND, WITH THE ONCE SHORTWAVE TROUGH
DEEPENING INTO ONE ON A MUCH LARGER SCALE, A SIGNIFICANTLY
COOLER AIRMASS WILL BE INFLICTED ACROSS THE REGION WITH
DOMINATING NORTHWEST FLOW. HIGH TEMPERATURES SATURDAY WILL
THEREFORE BE IN THE MID/UPPER 10S AT HIGHER TERRAIN REGIONS AND
LOW TO UPPER 20S ELSEWHERE.
ANY LINGERING SNOW SHOWERS FINALLY CEASE BY SATURDAY NIGHT,
YIELDING DRY CONDITIONS THROUGH THE REST OF THE WEEKEND AND INTO
THE BEGINNING OF NEXT WEEK AS HIGH PRESSURE BUILDS IN AND
BECOMES SITUATED ACROSS MUCH OF EASTERN CONUS BY MONDAY. LOW
TEMPERATURES SATURDAY NIGHT WILL THEN FALL WIDELY TO THE SINGLE
DIGITS WITH NEGATIVE SINGLE DIGITS IN THE MOUNTAINS (POSSIBLE
POCKETS OF NEGATIVE LOW 10S IN THE HIGHEST PEAKS OF THE
SOUTHWEST ADIRONDACKS). HIGHS SUNDAY WILL THEN ONLY REACH THE
SINGLE DIGITS ACROSS HIGHER TERRAIN TO THE UPPER 10S AND POCKETS
OF LOW 20S IN THE VALLEYS. SUNDAY NIGHT, TEMPERATURES FALL ONCE
AGAIN TO THE NEGATIVE SINGLE DIGITS TO SINGLE DIGITS WITH
POCKETS OF NEGATIVE LOW 10S AT THE HIGHEST PEAKS OF THE
SOUTHWEST ADIRONDACKS. THERE REMAINS SOME UNCERTAINTY IN WIND
SPEEDS FOR SATURDAY AND SUNDAY, BUT WILL CONTINUE TO MONITOR AS
COLD WEATHER ADVISORIES MAY BE NEEDED ESPECIALLY SATURDAY AND
SUNDAY NIGHTS.
TEMPERATURES WILL GRADUALLY BEGIN TO MODERATE FOR THE BEGINNING
OF NEXT WEEK AS FLOW SHIFTS TO THE SOUTHWEST AND THE HIGH
DEPARTS TO THE EAST. ADDITIONAL CHANCES FOR PRECIPITATION ARE
POSSIBLE TUESDAY AND WEDNESDAY AS AN UNSETTLED PATTERN LOOKS TO
RETURN. HIGHS MONDAY WILL REACH THE 10S TO 20S BEFORE LOWS FALL
TO THE SINGLE DIGITS TO LOW 10S. HIGHS TUESDAY WILL REACH
WIDESPREAD 20S WITH LOW 30S IN THE MID-HUDSON VALLEY WITH LOWS
TUESDAY NIGHT IN THE 10S AND 20S.
AVIATION /23Z WEDNESDAY THROUGH MONDAY/
THROUGH 00Z FRIDAY...AREA OF LIGHT TO MODERATE RAIN WILL
CONTINUE ACROSS THE TAF SITES THROUGH AROUND 04Z-06Z/THU, WITH
MVFR VSBYS AND MVFR/IFR CIGS DEVELOPING. SOME SNOW COULD MIX IN
TOWARD/AFTER 04Z/THU AT KPSF, AND PERHAPS ENDING AS A MIX OF
RAIN AND SNOW BETWEEN 04Z-06Z/THU AT KGFL AND KALB. MVFR CIGS
MAY LINGER FOR SEVERAL HOURS AT KGFL/KALB BEFORE LIFTING TO VFR
AFTER 08Z/THU. HOWEVER, MVFR/IFR CIGS MAY CONTINUE INTO THURSDAY
MORNING AT KPSF. IN ADDITION, AFTER THE RAIN ENDS, THERE COULD
BE A BRIEF PERIOD OF FOG AT KPOU PRODUCING IFR/LIFR CONDITIONS.
MVFR CIGS MAY LINGER THROUGHOUT THURSDAY AT KPSF, WITH
OCCASIONAL VFR CIGS EXPECTED ELSEWHERE. AS A WEAK COLD FRONT
SETTLES SOUTHWARD IN THE AFTERNOON, A FEW FLURRIES/SNOW SHOWERS
COULD PRODUCE MVFR VSBYS/CIGS AT KGFL AND KALB.
LIGHT/VARIABLE WINDS WILL BECOME WEST TO NORTHWEST AT 5-10 KT
LATER TONIGHT, INCREASING TO 8-12 KT THURSDAY WITH A FEW GUSTS
OF 15-20 KT POSSIBLE.
OUTLOOK...
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
FRIDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHSN.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...GANT
NEAR TERM...GANT/KL
SHORT TERM...GANT
LONG TERM...GANT
AVIATION...KL/JPV
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