846
FXUS61 KALY 191121
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
621 AM EST THU DEC 19 2024
SYNOPSIS
BEHIND A DEPARTING STORM SYSTEM, DRIER AND SEASONABLE
WEATHER IS EXPECTED TODAY WITH DECREASING CLOUDS AND A BREEZY
MORNING. A CLIPPER SYSTEM WILL RETURN THE THREAT FOR SOME LIGHT SNOW
TO THE ENTIRE REGION FOR FRIDAY INTO SATURDAY, WITH MUCH COLDER
TEMPERATURES EXPECTED OVER THE WEEKEND.
NEAR TERM /UNTIL 6 PM THIS EVENING/
AS OF 621 AM EST...SURFACE LOW PRESSURE IS LOCATED NEAR THE
SOUTHEASTERN CORNER OF NOVA SCOTIA. THIS SYSTEM WILL CONTINUE
TO RAPIDLY DEPART OFF TO THE NORTHEAST ACROSS ATLANTIC CANADA
FOR THIS MORNING. IR SATELLITE IMAGERY STILL SHOWS FAIRLY
WIDESPREAD CLOUDS OVER THE AREA, BUT THE DEEPEST MOISTURE IS NOW
EAST OF THE AREA AND MAINLY SHALLOW STRATOCU REMAINS BEHIND.
SOME BREAKS ARE ALSO STARTING TO OCCUR FOR SOME VALLEY AREAS AND
THERE WILL BE INCREASING AMOUNTS OF BREAKS IN THE CLOUD COVER
AS THE MORNING PROGRESSES. STILL, NORTHERN, WESTERN AND HIGH
TERRAIN AREAS WILL PROBABLY STAY FAIRLY CLOUDY THROUGH A GOOD
PART OF THE DAY. SOME DIURNAL CU OR STRATOCU MAY START TO RE-
DEVELOP IN VALLEY AREAS DURING THE AFTERNOON AS WELL, SO MOST
AREAS WILL JUST BE PARTLY TO MOSTLY CLOUDY FOR THE DAYLIGHT
HOURS TODAY.
WITH THE COLDER AIR WORKING ITS WAY INTO THE AREA, BRIEF LAKE
EFFECT SNOW SHOWERS HAVE DEVELOPED OFF LAKE ONTARIO, WHICH
COULD IMPACT THE WESTERN ADIRONDACKS INTO THE MORNING HOURS. ANY
PRECIP LOOKS FAIRLY LIGHT AND SHALLOW, WITH LITTLE SNOWFALL
ACCUMULATION EXPECTED. AS HIGH PRESSURE SLIDES ACROSS ONTARIO,
THE THREAT FOR LAKE EFFECT WILL DIMINISH BY THIS AFTERNOON AS
INVERSION HEIGHTS START TO LOWER.
WINDS HAVE BEEN STARTING TO PICKUP BEHIND THE DEPARTING STORM
SYSTEM, THANKS TO A DEVELOPING PRESSURE GRADIENT. BREEZY
CONDITIONS ARE POSSIBLE THIS MORNING, WITH SOME GUSTS IN THE
15 TO 30 MPH RANGE. HOWEVER, WINDS SHOULD START TO DIMINISH
TOWARDS AFTERNOON, AS HIGH PRESSURE STARTS TO GET CLOSER TO THE
AREA.
TEMPS LOOK FAIRLY SEASONABLE FOR TODAY WITH HIGHS A LITTLE
COOLER THAN YESTERDAY. MOST AREAS WILL TOP OUT IN THE 30S THIS
AFTERNOON.
SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/
KEY MESSAGE:
- A LIGHT SNOW ACCUMULATION IS LIKELY ACROSS THE FORECAST AREA
FOR FRIDAY INTO SATURDAY WITH SLIPPERY TRAVEL BEING THE MAIN
IMPACT.
DISCUSSION:
DRY AND QUIET WEATHER IS EXPECTED FOR TONIGHT. HIGH PRESSURE
WILL BE PASSING BY TO THE NORTH ACROSS QUEBEC WHILE THE NEXT
SYSTEM STATS TO APPROACH FROM THE GREAT LAKES AND MIDWEST.
DESPITE SOME INCREASING MID AND HIGH LEVEL CLOUDS, TEMPS WILL
FALL INTO THE TEENS AND 20S FOR TONIGHT.
A CLIPPER SYSTEM WILL BE MOVING FROM THE MIDWEST TOWARDS THE
NORTHERN MID ATLANTIC STATES. THE SURFACE LOW WILL BE WEAKENING
AS A NEW STORM STARTS TO DEVELOP WELL OFF THE EASTERN SEABOARD
ON FRIDAY. ALTHOUGH THE MAIN SURFACE SYSTEM WILL BE SOUTH OF THE
REGION, THERE WILL BE A SHARP UPPER LEVEL TROUGH ASSOCIATED WITH
THIS SYSTEM. MOISTURE IS FAIRLY LIMITED AND THE BEST MOISTURE
PLUME ASSOCIATED WITH THE DEVELOPING COASTAL STORM WILL STAY
WELL EAST OF THE REGION. STILL, THE COMBINATION OF DECENT
FORCING, SOME LIFT THROUGH THE DENDRITIC GROWTH ZONE AND JUST
ENOUGH MOISTURE SHOULD ALLOW FOR A LIGHT SNOWFALL ACROSS THE
REGION FOR FRIDAY INTO SATURDAY. NBM SHOWS ABOUT 50% TO 75%
PROBABILITY OF AT LEAST AN INCH ACROSS A GOOD PART OF THE AREA,
INCLUDING THE MOHAWK VALLEY, CAPITAL REGION, CATSKILLS,
BERKSHIRES, NW CT AND MID HUDSON VALLEY. HOWEVER, PROBABILITIES
DROP OFF BELOW 30% FOR 4" OR GREATER, SO IT LOOKS TO BE A SUB-
ADVISORY TYPE OF EVENT. SNOWFALL RATES PROBABLY WON'T BE TOO
HIGH AT ANY ONE PARTICULAR TIME, BUT A LIGHT AND FLUFFY SNOW IS
LOOKING LIKELY. GUIDANCE SEEMS TO SUGGEST THAT THE MAIN TIMING
WILL BE BEGINNING AROUND OR SHORTLY AFTER MIDDAY FRIDAY AND
CONTINUING INTO THE OVERNIGHT BEFORE TAPERING OFF DURING THE DAY
ON SATURDAY. SOME BREAKS IN THE CLOUDS ARE EXPECTED BY SATURDAY
AFTERNOON, WITH BETTER CLEARING EXPECTED BY SATURDAY NIGHT.
LOCALLY SLIPPERY TRAVEL SEEMS TO BE MAIN THREAT WITH TYPE OF
EVENT.
TEMPS WILL ONLY BE IN THE MID 20S TO MID 30S ON FRIDAY WITH THE
CLOUDS AND LIGHT SNOW. THEY WILL FALL INTO THE TEENS AND 20S ON
FRIDAY NIGHT AND REMAIN AROUND THIS INTO THE DAY ON SATURDAY, AS
AN ARCTIC BOUNDARY CROSSES THE AREA. NORTHWESTERLY WINDS WILL
START TO PICK UP BY SATURDAY AFTERNOON AS WELL. BY SATURDAY
NIGHT, TEMPS WILL BE IN THE SINGLE DIGITS, ALTHOUGH SOME SPOTS
IN THE ADIRONDACKS WILL DROP BELOW ZERO. WIND CHILL VALUES LOOK
TO BE RATHER LOW, WITH VALUES OF 0 TO -15 F AND THE COLDEST
READINGS ACROSS THE HIGH TERRAIN. THIS COULD ALLOW FOR AN
INCREASED RISK FOR FROSTBITE AND HYPOTHERMIA FOR ANYONE OUTDOORS
FOR A PROLONGED PERIOD OF TIME.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
KEY MESSAGES:
- HIGH CONFIDENCE IN UNUSUALLY COLD TEMPERATURES SUNDAY AND SUNDAY
NIGHT.
- LIGHT PRECIPITATION REMAINS POSSIBLE FOR THE MIDDLE OF NEXT WEEK,
BUT CONFIDENCE IS LOW REGARDING TIMING, AMOUNT, AND TYPE OF ANY
PRECIP
DISCUSSION:
LONG TERM PERIOD BEGINS AT 12Z SUNDAY WITH THE CORE OF THE COLD AIR
ALOFT MOVING OVERHEAD AS THE UPPER TROUGH SLIDES EASTWARDS INTO
WESTERN NEW ENGLAND. SUNDAY REMAINS BREEZY WITH A 1036+ MB SURFACE
HIGH CENTERED TO OUR WEST OVER THE GREAT LAKES REGION. 850 MB
TEMPERATURES SUNDAY SHOULD APPROACH -20C ACROSS PORTIONS OF THE
ADIRONDACKS AND SOUTHERN GREENS, WHICH WILL TRANSLATE TO DAYTIME
HIGHS ONLY IN THE UPPER 10S TO AROUND 20 IN THE VALLEYS AND SINGLE
DIGIT HIGHS IN THE TERRAIN. SUNDAY NIGHT, THE SURFACE HIGH MOVES
OVERHEAD, ALLOWING FOR WINDS TO DIMINISH. ANY LINGERING LAKE EFFECT
CLOUDS SHOULD DIMINISH AS THE 850 MB RIDGE AXIS MOVES OVERHEAD. THIS
WILL LEAD TO VERY EFFICIENT RADIATIONAL COOLING CONDITIONS,
ESPECIALLY FOR ANY AREAS THAT HAVE SNOW ON THE GROUND. SUNDAY NIGHT
WILL LIKELY BE THE COLDEST NIGHT SO FAR THIS YEAR WITH LOWS DROPPING
BELOW 0 FOR MOST HIGH TERRAIN AREAS AND SINGLE DIGIT LOWS EVEN IN
THE VALLEYS. THE COLDEST TEMPERATURES WILL BE ACROSS THE ADKS AND
SOUTHERN GREENS WHERE OVERNIGHT LOWS COULD APPROACH -10F. THE
CURRENTLY EXPECTED APPARENT TEMPERATURES/WIND CHILLS FALL SHORT OF
COLD WEATHER ADVISORY CRITERIA AS THE WINDS WILL BE DIMINISHING
SUNDAY NIGHT WHEN WE SEE THE COLDEST TEMPERATURES.
AFTER A VERY COLD START TEMPERATURES SHOULD MODERATE AS THE UPPER
RIDGE AXIS MOVES OVERHEAD AND WINDS TURNING TO THE SOUTHWEST ALLOW
FOR WARM ADVECTION INTO OUR REGION. NEVERTHELESS, HIGHS WILL STILL
RUN SEVERAL DEGREES BELOW NORMAL WITH HIGHS RANGING FROM 10S IN THE
HIGH TERRAIN TO 20S IN THE VALLEYS. SUNDAY AND MONDAY SHOULD BE
MAINLY DRY WITH LARGE-SCALE SUBSIDENCE IN PLACE.
MONDAY NIGHT THROUGH THURSDAY...THE SURFACE HIGH SLIDES TO THE EAST
MONDAY NIGHT AS THE FIRST IN A SERIES OF UPPER SHORTWAVES APPROACHES
FROM THE WEST. FORECAST CONFIDENCE DECREASES SUBSTANTIALLY BEGINNING
TUESDAY AS THE UPPER FLOW PATTERN BECOMES VERY CONVOLUTED WITH
MULTIPLE SHORTWAVE DISTURBANCES MOVING THROUGH THE MEAN FLOW ALOFT.
GIVEN THE SMALL WAVELENGTH OF THESE FEATURES, THEY WILL NOT BE WELL
RESOLVED BY THE RELATIVELY COARSE GLOBAL MODELS, AND THUS WE WILL
LIKELY SEE SEVERAL CHANGES TO THE FORECAST AROUND CHRISTMAS OVER THE
NEXT SEVERAL DAYS. NEVERTHELESS, THE MOST LIKELY SCENARIO IS FOR
INCREASING PRECIP CHANCES LATE MONDAY NIGHT AND TUESDAY, WITH SLIGHT
CHANCE TO LOW-END CHANCE POPS CONTINUING THROUGH THURSDAY.
INITIALLY, TEMPERATURES TUESDAY SHOULD BE COLD ENOUGH TO SUPPORT
MAINLY SNOW FOR WHATEVER PRECIP DOES FALL, BUT PRECIPITATION IS
CURRENTLY EXPECTED TO REMAIN ON THE LIGHT SIDE TUESDAY AND BEYOND.
NBM PROBABILITIES FOR >1" OF SNOW IN 24 HOURS TOP OUT AT AROUND 30-
40% FOR TUESDAY AND WEDNESDAY ACROSS THE ADIRONDACKS WITH LOWER
PROBABILITIES ELSEWHERE. NEVERTHELESS, WILL KEEP A CLOSE EYE ON
FORECAST TRENDS OVER THE COMING DAYS GIVEN THE EXPECTED UPTICK IN
HOLIDAY TRAVEL. LOOKING AHEAD TO DAYS 8-14, THE CPC IS LEANING
TOWARDS ABOVE NORMAL TEMPERATURES AND PRECIP.
AVIATION /12Z THURSDAY THROUGH MONDAY/
AS OF 6:15 AM EST, FLYING CONDITIONS HAVE IMPROVED TO VFR AT
ALB/GFL/POU BUT REMAIN VFR AT PSF WITH CIGS NEAR 2000 FT. EXPECTING
MVFR CIGS TO PERSIST AT PSF THROUGH THE MIDDLE OF THIS AFTERNOON
BEFORE CLOUDS SCATTER OUT. AT THE OTHER TERMINALS, VFR CONDITIONS
SHOULD PERSIST THROUGH MOST OF THE TAF PERIOD. SCT TO BKN SKIES
EXPECTED TODAY AND TONIGHT WITH CLOUD BASES BETWEEN 4000-6000 FT
TODAY DECREASING TO 3500-4500 FT TONIGHT. WHILE CURRENT THINKING IS
THAT PSF SHOULD SEE VFR CONDITIONS TONIGHT AS WELL, THERE MAY BE
SCATTERED CLOUDS BETWEEN 2000-3000 FT LINGERING THROUGH TONIGHT.
HIGH CLOUDS ALSO INCREASE TONIGHT AHEAD OF OUR NEXT WEATHER SYSTEM.
WEST WINDS THIS MORNING ARE GUSTING HIGHER THAN EXPECTED IN THE
PREVIOUS TAF ISSUANCE AT ALB/PSF, SO HAVE BUMPED UP THE WINDS AT
THESE SITES THIS MORNING. THE LOW-LEVEL JET IS EXPECTED TO WEAKEN
THROUGH THE DAY TODAY, AND SO MORE MINOR ADJUSTMENTS TO THE PREVIOUS
TAFS WERE MADE BEYOND 15Z TODAY, AS WE ARE STILL EXPECTING 15-20 KT
GUSTS FROM MID-MORNING THROUGH LATE THIS AFTERNOON AT ALL TERMINALS.
GUSTS DIMINISH AROUND SUNSET AND WINDS VEER TO THE NORTH/NORTHWEST,
AND THEN EVENTUALLY SWITCH TO THE NORTHEAST AT 4-7 KT BETWEEN 00 AND
04Z TONIGHT.
OUTLOOK...
FRIDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SN.
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.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
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
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