584
FXUS61 KALY 200845
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
345 AM EST FRI DEC 20 2024
SYNOPSIS
AN UPPER LEVEL DISTURBANCE WILL BRING PERIODS OF SNOW
FOR TODAY INTO TOMORROW WITH MOST AREAS SEEING A LIGHT ACCUMULATION.
IT WILL TURN BREEZY LATER TOMORROW ALONG WITH CLEARING SKIES AND
MUCH COLDER TEMPERATURES FOR THE REST OF THE WEEKEND. ANOTHER CHANCE
OF LIGHT SNOW IS EXPECTED FOR MONDAY NIGHT INTO CHRISTMAS EVE.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE:
-LIGHT SNOW EXPECTED TODAY AND TONIGHT DUE TO UPPER LEVEL
DISTURBANCE WILL RESULT IN LOCALLY SLIPPERY CONDITIONS,
ALTHOUGH THERE IS HIGH CONFIDENCE (GREATER THAN 80%) THAT
TOTAL AMOUNTS WILL REMAIN UNDER ADVISORY CRITERIA (4").
DISCUSSION:
AS OF 345 AM EST...UPPER LEVEL DISTURBANCE AND ASSOCIATED
WEAK SURFACE LOW WAVE OF LOW PRESSURE IS LOCATED OVER THE
MIDWEST. WELL AHEAD OF THIS FEATURE, PLENTY OF MID LEVEL CLOUDS
HAVE ALREADY BEEN STREAMING INTO OUR AREA, WITH OVERCAST SKIES
IN PLACE. HIGH PRESSURE LOCATED TO THE NORTH OVER QUEBEC AS
ALLOWED FOR A COLD NORTHERLY FLOW AND THE ENTIRE FORECAST AREA
HAS FALLEN INTO THE TEENS AND 20S.
THE UPPER LEVEL DISTURBANCE WILL HEAD TOWARDS THE EASTERN OHIO
VALLEY AND NORTHERN MID ATLANTIC STATES FOR THIS MORNING. THIS
APPROACHING UPPER LEVEL ENERGY WILL HELP DEVELOP A COASTAL WAVE,
BUT THIS SURFACE FEATURE WILL REMAIN TOO FAR SOUTH AND EAST OF
OUR AREA FOR A DIRECT IMPACT. HOWEVER, IT MAY HAVE SOME INDIRECT
INFLUENCE, AS IT ALLOWS FOR THE UPPER LEVEL SHORTWAVE TO
SHARPEN. ALTHOUGH THE PRIMARY SURFACE LOW MOVING ACROSS THE
MIDWEST WILL BE SLIDING BY TO THE SOUTH AND WEAKENING AS THE
SECONDARY SYSTEM TAKES OVER, THE UPPER LEVEL ENERGY WILL HELP
PROVIDE ENOUGH LIFT ACROSS THE AREA. WHILE THERE WON'T BE A TON
OF MOISTURE, THERE WILL BE JUST ENOUGH TO ALLOW FOR AN AREA OF
LIGHT SNOW TO BREAK OUT ACROSS OUR AREA, AS SOME WEAK WARM
ADVECTION OCCURS ON THE LEADING EDGE OF THE SYSTEM.
SNOW WILL BREAK OUT ACROSS THE ADIRONDACKS BY THE LATE MORNING
HOURS AND EXPAND ACROSS THE ENTIRE AREA DURING THE AFTERNOON
HOURS. MODEL SOUNDINGS SUGGEST THE BEST LIFT IS PROBABLY UNDER
THE DENDRITIC GROWTH ZONE FOR MOST OF THE TIME, ALTHOUGH IT MAY
BRIEFLY INTERSECT IT, ESPECIALLY ACROSS THE CATSKILLS. SNOWFALL
RATES LOOK LIGHT AND 00Z SPC HREF PROBS FOR >1" RATES ARE ALL
UNDER 20%. MOST LIKELY RATES DURING THE PEAK THIS AFTERNOON ARE
IN THE 0.25 TO 0.50" PER HOUR RANGE AND ONLY HIT THAT BRIEFLY.
AS A RESULT, SNOW RATES SHOULD BE MANAGEABLE, BUT THE COLD
TEMPS/GROUND WILL ALLOW FOR EASY ACCUMULATION AND ANY UNTREATED
SURFACES WILL BE SLIPPERY. THE AFTERNOON SHOULD BE ON AND OFF
LIGHT SNOW WITH TEMPS REACHING THE MID 20S TO MID 30S.
CAMS SUGGEST MOST AREAS WILL SEE A LULL AROUND 00Z, ALTHOUGH THE
CATSKILLS AND MOHAWK VALLEY MAY HAVE THE BEST CHANCE FOR SEEING
MORE PERSISTENT SNOW THIS EVENING. MEANWHILE, IT WILL REMAIN
CLOUDY AND CHILLY FOR THIS EVENING INTO TONIGHT WITH LOWS
FALLING INTO THE TEENS TO MID 20S.
ANOTHER BATCH OF SNOW MAY START TO REDEVELOP FOR THE LATE NIGHT
HOURS AND TOWARDS DAYBREAK SATURDAY AS THE UPPER LEVEL TROUGH
AXIS ACROSS THE AREA. THIS COULD ALLOW FOR ANOTHER BATCH OF
STEADY SNOW TO OCCUR, ESPECIALLY OVER THE CAPITAL REGION, FOR
THE LATE NIGHT HOURS. AGAIN, RATES WON'T BE ANYTHING TOO HIGH,
BUT IT WILL ALLOW FOR SOME ADDITIONAL LIGHT ACCUMULATION. BY
DAYBREAK, MOST AREAS IN WESTERN NEW ENGLAND WILL HAVE A COATING
TO AN INCH, WITH 1 TO 3 INCHES ACROSS EASTERN NY, WITH THE
HIGHEST TOTALS IN THE MOHAWK AND SCHOHARIE VALLEYS, HELDERBERGS
AND EASTERN CATSKILLS. MUCH OF THE CAPITAL REGION WILL SEE
AROUND 2 INCHES OF FLUFFY SNOW.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
KEY MESSAGE:
-BELOW NORMAL TEMPERATURES EXPECTED THIS WEEKEND WITH FRIGID
OVERNIGHT LOWS ON BOTH SATURDAY AND SUNDAY NIGHT.
DISCUSSION:
SOME ADDITIONAL LIGHT SNOW MAY LINGER INTO SATURDAY MORNING,
ESPECIALLY WITHIN THE CAPITAL REGION, WHERE HUDSON-MOHAWK
CONVERGENCE COULD ALLOW FOR SNOWFALL TO CONTINUE FOR A FEW
HOURS. OTHERWISE, PRECIP WILL BE WINDING DOWN TOWARDS MIDDAY, AS
THE TROUGH AXIS SHIFTS EASTWARD AND FAST DEVELOPING COASTAL LOW
LIFTS INTO ATLANTIC CANADA. NORTHWEST FLOW IN PLACE WILL ALLOW
FOR SOME LAKE EFFECT SNOW SHOWERS ACROSS CENTRAL NY, BUT MOST OF
THIS ACTIVITY WILL STAY WEST OF THE AREA, WITH JUST SOME
ADDITIONAL LIGHT SNOW SHOWERS OR FLURRIES IMPACTING WESTERN
AREAS. SOME BREAKS IN THE CLOUDS WILL START TO OCCUR BY LATE
MORNING OR AFTERNOON AND NORTHWEST WINDS WILL START TO PICK UP
AND BECOME GUSTY, AS THE PRESSURE GRADIENT INCREASES BETWEEN THE
DEPARTING STORM AND HIGH PRESSURE NORTH OF THE GREAT LAKES. HIGH
TEMPS WILL ONLY TOP OUT IN THE TEENS AND 20S AND IT WILL FEEL
EVEN COLDER WITH GUSTY WINDS, WHICH MAY EXCEED 25 MPH AT TIMES.
VERY COLD TEMPS ARE EXPECTED ON SATURDAY NIGHT. WHILE NORTHWEST
WINDS WILL DIMINISH SLIGHTLY, THEY STILL WILL BE A LITTLE BREEZY
ON SATURDAY NIGHT WITH WINDS OF AROUND 10 MPH AND GUSTS UP TO
20 MPH AT TIMES. SKIES WILL BE CLEARING OUT AS HIGH PRESSURE
GETS CLOSER TO THE AREA. LOWS WILL BE IN THE SINGLE DIGITS FOR
MOST, WITH HIGH CONFIDENCE (GREATER THAN 75%) FOR BELOW ZERO
READINGS ACROSS THE ADIRONDACKS (ACCORDING TO THE LATEST NBM).
WIND CHILL VALUES MAY COME CLOSE TO COLD ADVISORY CRITERIA IN
HIGH TERRAIN AREAS FOR LATE SATURDAY NIGHT.
ON SUNDAY INTO SUNDAY NIGHT, DRY WEATHER IS EXPECTED AS HIGH
PRESSURE BUILDS DIRECTLY OVER THE AREA. THIS SHOULD FOR WINDS TO
DIMINISH AND BECOME LIGHTER WITH PLENTY OF CLEAR SKIES.
HOWEVER, TEMPS WILL REMAIN VERY COLD, AS 850 HPA TEMPS FALL TO
-12 TO -18 C. HIGHS LOOK TO ONLY REACH THE TEENS FOR MOST AREAS
ON SUNDAY. HAVE LEANED TOWARDS THE LOWER END OF THE BLENDED
GUIDANCE FOR SUNDAY NIGHT CONSIDERING THE GOOD RADIATIONAL
COOLING SETUP AND FRESH SNOWPACK, WITH LOWS NEAR ZERO IN THE
CAPITAL REGION AND MID HUDSON VALLEY, WITH BELOW ZERO TEMPS IN
THE OUTLYING AREAS AND HIGHER TERRAIN.
LONG TERM /MONDAY THROUGH THURSDAY/
KEY MESSAGES:
- CONFIDENCE IS INCREASING IN A WIDESPREAD LIGHT SNOWFALL ACROSS THE
REGION ON MONDAY NIGHT INTO TUESDAY.
- FORECAST HAS TRENDED DRIER FOR CHRISTMAS DAY THROUGH THE END OF
THE WEEK, BUT FORECAST CONFIDENCE REMAINS LOW THIS FAR OUT.
DISCUSSION:
LONG TERM PERIOD WILL START OFF QUITE COLD MONDAY MORNING WITH
TEMPERATURES BELOW 0F FOR MANY HIGH TERRAIN AREAS. HIGH PRESSURE AND
UPPER RIDGING OVERHEAD WILL KEEP US DRY THROUGH THE DAY MONDAY, BUT
AS THESE FEATURES SLIDE OFF TO THE EAST, OUR LOW-LEVEL FLOW TURNS
SOUTHWESTERLY AND ALLOWS FOR WARM ADVECTION INTO THE REGION AHEAD OF
AN APPROACHING UPPER SHORTWAVE AND ASSOCIATED SURFACE LOW THAT WILL
MOVE IN FROM THE GREAT LAKES REGION MONDAY NIGHT. WHILE DAYTIME
HIGHS WILL BE WARMER THAN SUNDAY, DAYTIME HIGHS WILL STILL BE
SEVERAL DEGREES BELOW NORMAL WITH TEMPERATURES RANGING FROM THE 10S
IN THE HIGH TERRAIN TO 20S IN THE VALLEYS.
MONDAY NIGHT THROUGH TUESDAY...DETERMINISTIC AND ENSEMBLE GUIDANCE
CONTINUE TO COME INTO BETTER AGREEMENT ON THE POTENTIAL FOR A LIGHT
SNOWFALL EVENT MONDAY NIGHT AND TUESDAY. THE AFOREMENTIONED UPPER
SHORTWAVE AND SURFACE LOW ARE EXPECTED TO WEAKEN AS THEY TRACK
THROUGH UPSTATE NY INTO NEW ENGLAND, BUT UPPER DYNAMICS AND
INCREASING MOISTURE SHOULD ALLOW FOR MOST AREAS TO SQUEEZE OUT SOME
LIGHT PRECIP. NBM PROBS FOR MEASURABLE PRECIP HAVE INCREASED
CONSIDERABLY FROM LAST NIGHT, AND ARE NOW >60% REGION-WIDE FOR
MONDAY NIGHT THROUGH TUESDAY TIMEFRAME. THERMAL PROFILES FAVOR
MAINLY SNOW, EVEN IN THE VALLEYS, BUT PRECIP WILL LIKELY BE LIGHT.
CONFIDENCE REMAINS LOW IN EXACT AMOUNTS THIS FAR OUT, THIS LOOKS
LIKE A SUB-ADVISORY TYPE EVENT WITH PERHAPS UP TO A COUPLE INCHES OF
SNOW POSSIBLE. NEVERTHELESS, WITH INCREASED TRAVEL AROUND CHRISTMAS,
SLIPPERY TRAVEL CONDITIONS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
THIS SYSTEM ALSO LOOKS TO COME IN SLIGHTLY EARLIER COMPARED TO THE
PREVIOUS FORECAST, WITH PRECIPITATION POTENTIALLY BEGINNING AS EARLY
AS 06Z TUESDAY FOR AREAS WEST OF I-87. WITH FASTER PROGRESSION OF
THE SYSTEM, WE WILL SEE MORE CLOUDS MONDAY AFTERNOON AND NIGHT, SO
OVERNIGHT LOWS MONDAY WERE BUMPED UP A FEW DEGREES FROM THE PREVIOUS
FORECAST, WITH MOST AREAS IN THE 10S EXCEPT FOR SOME SINGLE DIGITS
IN THE HIGH TERRAIN. HIGHS TUESDAY WILL BE WARMER, WITH 20S FOR THE
TERRAIN TO MID 30S IN THE VALLEYS ESPECIALLY SOUTH OF I-90.
TUESDAY NIGHT THROUGH FRIDAY...SNOW SHOWERS SHOULD TAPER OFF TUESDAY
EVENING, WITH THE REMAINDER OF THE LONG TERM CURRENTLY LOOKING DRIER
COMPARED TO PREVIOUS FORECASTS. THIS COMES WITH A DISCLAIMER THAT
THERE IS STILL LOW FORECAST CONFIDENCE THIS FAR OUT GIVEN THAT THE
UPPER FLOW PATTERN BECOMES VERY CONVOLUTED BY THE MIDDLE OF NEXT
WEEK WITH A SPLIT FLOW REGIME AND SEVERAL SHORTWAVE DISTURBANCES
TRACKING ACROSS NORTH AMERICA. THAT BEING SAID, RECENT TRENDS HAVE
BEEN FOR MORE CONFLUENT FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE
OVER OUR AREA DURING THIS TIMEFRAME. THUS, HAVE BACKED OFF ON POPS
DURING THIS TIME PERIOD FROM WHAT NBM GUIDANCE HAD WITH JUST SOME
SLIGHT CHANCES, MAINLY IN THE HIGH TERRAIN. DAYTIME HIGHS SHOULD BE
CLOSE TO NORMAL, MAINLY IN THE 30S WITH SOME 20S IN THE HIGH
TERRAIN. FOR OVERNIGHT LOWS, WE ARE CURRENTLY FORECASTING MAINLY 10S
(TERRAIN) TO 20S (VALLEYS), BUT IF RECENT TRENDS CONTINUE FOR HIGH
PRESSURE OVERHEAD DURING THIS TIME PERIOD, THEN OVERNIGHT LOWS COULD
END UP SEVERAL DEGREES COOLER THAN THE CURRENT FORECAST. AT THIS
TIME, HOWEVER, CONFIDENCE IS TOO LOW TO DEVIATE SIGNIFICANTLY FROM
THE NBM.
AVIATION /08Z FRIDAY THROUGH TUESDAY/
THROUGH 06Z SATURDAY...FLYING CONDITIONS ARE CURRENTLY VFR AT ALL
TERMINALS AND SHOULD STAY VFR THROUGH THE REMAINDER OF TONIGHT. LOW
PROBABILITY FOR SOME PATCHY CLOUDS BETWEEN 2000-3000 FT LATE TONIGHT
AT PSF, BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE MVFR CIGS.
CLOUD BASES LOWER THROUGH THE MORNING TOMORROW, BECOMING OVERCAST
BETWEEN 3000-4000 FT BY EARLY TO MID-MORNING. LIGHT SNOW IS EXPECTED
TO BEGIN TOMORROW AFTERNOON. STILL MAY NEED TO ADJUST TIMING
SLIGHTLY, BUT BETWEEN 17-19Z AT ALB/GFL/POU AND 18-20Z AT PSF STILL
SEEMS LIKE THE MOST LIKELY START TIME OF SNOW. SNOW WILL LEAD TO IFR
VSBYS, POSSIBLY DOWN TO 1SM TOMORROW AFTERNOON AND EARLY EVENING.
EXPECTING CIGS TO DROP BELOW FUEL-ALTERNATE CRITERIA AS WELL
TOMORROW SHORTLY AFTER SNOW BEGINS, WITH POCKETS OF IFR CIGS
POSSIBLE AS WELL TOMORROW AFTERNOON AND EVENING. SNOW MAY TAPER OFF
TOMORROW EVENING AND EARLY TOMORROW NIGHT FOR A PERIOD, BUT SHOULD
REDEVELOP AROUND 06Z. EVEN IF SNOW DOES TAPER OFF FOR A PERIOD, CIGS
SHOULD REMAIN BELOW 2000 FT. WINDS WILL BE FROM THE NORTHEAST AT 4-8
KT THROUGH MOST OF THE TAF PERIOD, BECOMING MORE NORTHERLY AT 4-8 KT
TOMORROW AFTER 00-03Z.
OUTLOOK...
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.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
CHRISTMAS DAY: LOW OPERATIONAL IMPACT. NO SIG WX.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...MAIN
AVIATION...MAIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page