237
FXUS61 KALY 181930
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
230 PM EST WED DEC 18 2024
SYNOPSIS
A FAST MOVING STORM SYSTEM WILL RETURN THE THREAT FOR
RAIN AND HIGHER ELEVATION SNOW TO THE REGION FOR THIS AFTERNOON INTO
TONIGHT. DRIER AND MORE SEASONABLE WEATHER IS EXPECTED FOR THURSDAY
BEFORE A WIDESPREAD LIGHT SNOW IMPACTS THE AREA FOR FRIDAY INTO
FRIDAY NIGHT. MUCH COLDER TEMPERATURES ARE EXPECTED ACROSS THE
REGION FOR THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE:
- FAST MOVING STORM SYSTEM WILL IMPACT THE REGION THIS AFTERNOON
INTO TONIGHT WITH A LIGHT SNOW ACCUMULATION ACROSS THE HIGH
TERRAIN.
UPDATE...AS OF 1250 PM...THE FORECAST REMAINS IN GOOD SHAPE WITH
THIS UPDATE WITH FEW CHANGES NEEDED. MADE MINOR ADJUSTMENTS TO
TEMPERATURES TO REFLECT LATEST OBS. ADJUSTMENTS WERE ALSO MADE
TO POPS TO REFLECT LATEST SCANS OF THE KENX RADAR WHICH SHOW A
BAND OF LIGHT SNOW ENTERING THE SOUTHWEST ADIRONDACKS. OTHERWISE
ALL REMAINS STEADY WITH ADDITIONAL DETAILS IN THE PREVIOUS
DISCUSSION BELOW.
PREVIOUS DISCUSSION....
AS OF 620 AM EST...IR SATELLITE IMAGERY CONTINUES TO SHOW
FAIRLY WIDESPREAD CLOUDS OVER MUCH OF THE REGION, WITH STRATUS
AND STRATOCU ACROSS NORTHERN AREAS WITHIN THE WEST-SOUTHWEST
FLOW ALOFT. FURTHER SOUTH, THERE ARE MORE BREAKS, ALTHOUGH THERE
ARE PLENTY OF PASSING HIGH CLOUDS.
WHILE THE MORNING WILL START OFF DRY, CLOUDS WILL CONTINUE TO BE
IN PLACE, AS UPSTREAM SATELLITE IMAGERY SHOWS CLOUDS WILL
CONTINUE TO SPREAD TOWARDS THE AREA THROUGH THE MORNING HOURS,
ALLOWING FOR ALL AREAS TO BECOME OVERCAST BY THE LATE MORNING
HOURS. TEMPS HAVE BEEN VARIABLE TO START THE DAY, AS NORTHERN
AREAS SEEING THE THICKER CLOUD COVER ARE STARTING OUT IN THE 30S
TO LOW 40S, WHILE SOUTHERN AREAS THAT SAW MORE BREAKS OVERNIGHT
ARE STARTING OUT IN THE MID 20S TO LOW 30S.
UPPER LEVEL DISTURBANCE WILL BE MOVING ACROSS THE GREAT LAKES
FOR TODAY AND WILL APPROACH THE AREA FOR TONIGHT. MEANWHILE, A
SURFACE STORM IS LOCATED OVER THE TENNESSEE VALLEY AND IT WILL
BE LIFTING NORTHEAST ACROSS THE MID ATLANTIC FOR LATER TODAY.
THE SURFACE LOW LOOKS TO PASS JUST SOUTHEAST OF THE AREA ALONG
THE NORTHEAST COAST FOR THIS EVENING, BEFORE PASSING OFF THE
COAST OF NEW ENGLAND FOR LATER TONIGHT.
DESPITE THE CLOUDS, A LIGHT SOUTHERLY FLOW WILL HELP TEMPS WARM
THIS MORNING. MOST AREAS WILL REACH THE UPPER 30S TO MID 40S
TOWARDS MIDDAY, ALTHOUGH HIGH TERRAIN AREAS WILL ONLY BE IN THE
LOW TO MIDDLE 30S.
ALTHOUGH TEMPS ALOFT WILL BE COOLING TODAY, THE BOUNDARY LAYER
WILL REMAIN SOMEWHAT MILD. AS THE LOW PRESSURE APPROACHES, AN
AREA OF STEADY PRECIP WILL BE MOVING INTO THE AREA FROM THE
WEST. PRECIP MAY ACTUALLY BEGIN ACROSS THE ADIRONDACKS FIRST BY
THE EARLY TO MID AFTERNOON HOURS, BEFORE SPREADING ACROSS THE
REST OF THE AREA FOR THE LATE AFTERNOON. ALTHOUGH TEMPS ALOFT
WILL SUPPORT SNOWFALL, THE BOUNDARY LAYER WILL BE WARM FOR MANY
AREAS. BECAUSE OF THIS, SNOWFALL WILL BE ELEVATION DEPENDENT,
WITH ONLY THE WESTERN AND CENTRAL ADIRONDACKS AND SOUTHERN
GREENS EXPECTED TO SEE ALL SNOW. MOST VALLEY AREAS WILL BE
SEEING JUST RAIN, ALTHOUGH A BRIEF CHANGEOVER OR MIX WITH SNOW
IS POSSIBLE LATE AS WET BULB EFFECTS ALLOWS THE SURFACE TO COOL
OFF, ESPECIALLY FOR AREAS NORTH AND WEST OF THE CAPITAL REGION
FOR LATE THIS EVENING.
MOST OF THE STEADY PRECIP SHOULD BE ENDING AROUND MIDNIGHT OR
SO, SO THIS WILL BE A QUICK STORM SYSTEM. QPF IS FAIRLY LIMITED,
BUT 1-4 INCHES OF SNOW IS EXPECTED FOR THE ADIRONDACKS AND
GREENS. ELSEWHERE FOR AREAS NORTH AND WEST OF THE CAPITAL REGION,
A COATING TO AN INCH OR SO WILL BE POSSIBLE AS RAIN CHANGES TO
SNOW BEFORE ENDING, WITH NO SNOW FOR AREAS SOUTH AND EAST OF THE
CAPITAL REGION. LOCALLY SLICK TRAVEL IS POSSIBLE FOR THE HIGHEST
TERRAIN. SNOW WILL BE WET, WITH LOW SNOW-TO-LIQUID RATIOS.
ALTHOUGH THE STEADY PRECIP WILL END TOWARDS MIDNIGHT, THE
PASSING UPPER LEVEL DISTURBANCE MAY STILL ALLOW FOR A FEW MORE
SNOW SHOWERS OVERNIGHT, MAINLY ACROSS THE HIGH TERRAIN OF
WESTERN NEW ENGLAND AND ACROSS LAKE-EFFECT FAVORED AREAS OF THE
ADIRONDACKS. ANY ADDITIONAL SNOW ACCUMULATION WILL JUST BE A
COATING TO AN INCH OR SO AND LIMITED TO JUST THE HIGHEST
TERRAIN. LOWS WILL FALL INTO THE MID 20S TO LOW 30S, WITH SOME
BREAKS EXPECTED IN THE CLOUD COVER BY LATE TONIGHT IN VALLEY
AREAS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
KEY MESSAGE:
-INCREASING POTENTIAL FOR A LIGHT SNOW ACCUMULATION ACROSS MUCH
OF THE REGION FRIDAY INTO FRIDAY NIGHT.
DISCUSSION:
BEHIND THE DEPARTING STORM SYSTEM, AN AREA OF HIGH PRESSURE WILL
BE PASSING BY TO THE NORTH FOR THURSDAY INTO THURSDAY NIGHT. ANY
LAKE EFFECT ACTIVITY SHOULD END EARLY THURSDAY, ALLOWING FOR
MAINLY DRY AND SEASONABLE WEATHER FOR THURSDAY INTO THURSDAY
NIGHT. NORTHWEST WINDS MAY BE A LITTLE BREEZY TO START ON
THURSDAY, BUT WINDS SHOULD DECREASE BY LATER IN THE DAY AND INTO
THURSDAY NIGHT.
UPPER LEVEL SHORTWAVE WILL BE MOVING TOWARDS THE AREA FROM THE
GREAT LAKES FOR FRIDAY AND PASSING ACROSS THE AREA ON FRIDAY
NIGHT. SURFACE CYCLOGENESIS WILL BE TAKING PLACE WELL OFFSHORE
THE EASTERN SEABOARD. WHILE THE COASTAL STORM WILL BE TOO FAR
AWAY TO HAVE MUCH OF A DIRECT IMPACT, IT MAY HELP ALLOW FOR SOME
LIGHT PRECIP TO BREAK OUT WITHIN THE CYCLONIC FLOW OF THE
PASSING UPPER LEVEL DISTURBANCE. WITH SURFACE TEMPS AND TEMPS
ALOFT SUFFICIENTLY COLD, ANY PRECIP WILL BE IN THE FORM OF LIGHT
SNOW. THE COLD AIR MASS IN PLACE SHOULD HELP PROMOTE DECENT
SNOW- TO- LIQUID RATIOS. PRECIP RATES WILL BE LIGHT, BUT
INTERMITTENT LIGHT SNOW IS EXPECTED BY LATE MORNING OR EARLY
AFTERNOON FRIDAY THROUGH THE REST OF THE DAY AND INTO A GOOD
PART OF FRIDAY NIGHT. NBM PROBABILITIES SHOW ABOUT A 20% TO 50%
OF AT LEAST 1 INCH ACROSS THE REGION. LATEST MOST LIKELY
FORECAST HAS ABOUT AN INCH OR TWO OF FLUFFY SNOW FOR MANY AREAS,
ESPECIALLY FROM THE CAPITAL REGION ON WESTWARD ACROSS THE
MOHAWK VALLEY AND CATSKILLS. DAYTIME TEMPS WILL ONLY BE IN THE
UPPER 20S TO MID 30S, AND LOWS ON FRIDAY NIGHT LOOK CHILLY IN
THE TEENS AND 20S.
LONG TERM /SATURDAY THROUGH TUESDAY/
KEY MESSAGES:
- HIGH CONFIDENCE IN VERY COLD TEMPERATURES THIS WEEKEND.
DISCUSSION:
HIGH-AMPLITUDE UPPER-LEVEL TROUGHING WILL BE CENTERED OVER THE
NORTHEAST SATURDAY MORNING BEHIND A DEPARTING UPPER SHORTWAVE AND
ASSOCIATED COASTAL LOW. NORTHWESTERLY FLOW REINFORCED BY A WEAKER
SHORTWAVE IMPULSE SATURDAY INTO SATURDAY NIGHT WILL DRIVE POTENT
COLD ADVECTION YIELDING 850-HPA TEMPERATURES BETWEEN -15 AND -20C,
AND PUSHING SURFACE TEMPERATURES 10 TO 20 DEGREES BELOW NORMAL FOR
MID TO LATE DECEMBER. BREEZY CONDITIONS SATURDAY INTO SATURDAY NIGHT
MAY PRODUCE BITTERLY COLD WIND CHILLS, WITH PORTIONS OF THE SOUTHERN
ADIRONDACKS POSSIBLY SEEING DANGEROUSLY COLD VALUES BELOW -20F.
SOME SNOW SHOWERS MAY LINGER INTO SATURDAY MORNING AS THE PREVIOUS
COASTAL LOW EXITS EASTWARD, ESPECIALLY WEST OF THE HUDSON NEARER TO
LAKE MOISTURE, AS WELL AS IN HIGHER TERRAIN EAST OF THE HUDSON DUE
TO UPSLOPE ENHANCEMENT, BUT DRY WEATHER WILL OTHERWISE RETURN ACROSS
THE REGION BY SATURDAY NIGHT. SATURDAY AFTERNOON HIGHS IN THE 10S TO
20S FOR MOST WILL FALL TO THE SINGLE DIGITS BELOW ZERO IN HIGHER
TERRAIN AND SINGLE DIGITS ABOVE ZERO AT LOWER ELEVATIONS SATURDAY
NIGHT, BUT GUSTY NORTHWEST WINDS WILL MAKE TEMPERATURES FEEL MUCH
COLDER. OVERNIGHT WIND CHILLS MAY FALL AS LOW AS 5F TO -10F WITHIN
THE MAJOR VALLEYS, AND -10F TO -25F IN HIGHER TERRAIN. CANADIAN
SURFACE HIGH PRESSURE BUILDING INTO THE REGION FROM THE NORTHWEST
SUNDAY WILL SEE CONTINUED COLD TEMPERATURES, AS HIGH REACH ONLY THE
SINGLE DIGITS TO MID TEENS IN HIGH TERRAIN AND MID-10S TO LOW 20S AT
LOWER ELEVATIONS. SUNDAY NIGHT WILL FEATURE SIMILARLY COLD
TEMPERATURES BETWEEN -10F AND 10F ACROSS THE REGION, BUT DIMINISHED
WINDS WILL REDUCE THE RISK FOR DANGEROUSLY COLD WIND CHILLS.
AS UPPER-LEVEL RIDGING BUILDS IN FROM THE WEST MONDAY INTO TUESDAY,
DEVELOPING SOUTHWESTERLY MID-LEVEL WILL PUSH TEMPERATURES BACK
TOWARD SEASONAL NORMS, WITH VALUES POSSIBLY RISING ABOVE FREEZING IN
THE MID-HUDSON VALLEY BY CHRISTMAS EVE AFTERNOON. LONG-RANGE
NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT THAT A SHORTWAVE TROUGH
ON THE BACKSIDE OF UPPER RIDGING WILL BRING LOW TO MEDIUM CHANCES
(20-40%) FOR PRECIPITATION INTO CHRISTMAS EVE NIGHT, WITH SNOW
REMAINING THE FAVORED P-TYPE FOR MUCH OF THE REGION.
AVIATION /20Z WEDNESDAY THROUGH MONDAY/
THROUGH 18Z THURSDAY...VFR CONDITIONS IN PLACE TO START THIS
AFTERNOON WITH INCREASING MID LEVEL CLOUDS. CONDITIONS WILL LOWER TO
MVFR LEVELS THIS EVENING BETWEEN 21Z-23Z AS RAIN QUICKLY DEVELOPS
FROM WEST TO EAST. A FEW HOURS AFTER ONSET, IFR CONDITIONS ARE
EXPECTED TO DEVELOP STARTING BETWEEN 01Z-03Z THU. RAIN MAY MIX WITH
SNOW AT KGFL AFTER 00Z THU, AND CHANGE TO SNOW AT KPSF. THIS WILL BE
A FAST-MOVING SYSTEM, SO PRECIP SHOULD END FROM WEST TO EAST BETWEEN
04Z-06Z. THERE COULD BE SOME LINGERING MIST AND MVFR CONDITIONS FOR
A FEW HOURS, THEN IMPROVING TO VFR AROUND 09Z-10Z AS BETTER MIXING
DEVELOPS. WINDS WILL BE SOUTH-SOUTHWEST AROUND 3-6 KT, BECOMING
NORTHWEST AND INCREASING TO 7-10 KT AFTER 06Z THU.
OUTLOOK...
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: MODERATE OPERATIONAL IMPACT. LIKELY SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SN.
SATURDAY: LOW OPERATIONAL IMPACT. BREEZY. SLIGHT 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...FRUGIS
NEAR TERM...FRUGIS/GANT
SHORT TERM...FRUGIS
LONG TERM...PICARD
AVIATION...JPV
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