752
FXUS61 KALY 211132
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
632 AM EST SAT DEC 21 2024
SYNOPSIS
LIGHT SNOW TAPERS OFF THIS MORNING, GIVING WAY TO A
MAINLY DRY REST OF THE DAY TODAY. AN UNUSUALLY COLD AIRMASS MOVES IN
THIS AFTERNOON AND LASTS INTO MONDAY, WITH WIND CHILLS EXPECTED TO
REACH COLD WEATHER ADVISORY CRITERIA IN SOME HIGH TERRAIN AREAS.
ANOTHER CLIPPER SYSTEM SHOULD BRING SOME ADDITIONAL LIGHT SNOW
MONDAY NIGHT INTO TUESDAY, WITH DRY WEATHER AND MODERATING
TEMPERATURES THEN EXPECTED THROUGH THE REMAINDER OF NEXT WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGE:
- LIGHT SNOW TAPERS TO SNOW SHOWERS THIS MORNING BEFORE ENDING.
SLIPPERY TRAVEL CONDITIONS ARE POSSIBLE THIS MORNING.
DISCUSSION:
UPDATE...AS OF 6:30 AM EST
LIGHT SNOW CONTINUES ACROSS THE
REGION THIS MORNING, ALTHOUGH WE'RE STARTING TO SEE SOME MORE
HOLES IN THE PRECIP SHIELD AS DRIER AIR WORKS ITS WAY INTO THE
REGION AND THE BEST UPPER FORCING BEGINS TO MOVE OFF TO THE
EAST OVER THE NEXT FEW HOURS. 2 MAIN AREAS OF LOCALIZED
ENHANCEMENT IN SNOWFALL INTENSITY PER LATEST RADAR IMAGERY ARE
1) ACROSS THE MID HUDSON VALLEY AND WESTERN CT CLOSER TO THE
INVERTED TROUGH AND 2) AROUND THE CAPITAL DISTRICT WHERE MOHAWK
HUDSON CONVERGENCE IS OCCURRING. ASOS OBS SHOW NORTHERN FLOW
DOWN THE HUDSON VALLEY AND WESTERLY FLOW DOWN THE MOHAWK VALLEY,
WITH THE NYS MESONET SHOWING THE BEST LOCALIZED CONVERGENCE
ACROSS SARATOGA AND SCHENECTADY COUNTIES. THIS MHC BAND SHOULD
GRADUALLY SHIFT SOUTH AND EASTWARDS THROUGH THE NEXT FEW HOURS,
BEFORE EVENTUALLY TAPERING OFF BY MID-MORNING. OVERALL, MOSTLY
MINOR ADJUSTMENTS WITH THIS UPDATE, AS PREVIOUS FORECAST REMAINS
IN GOOD SHAPE. PLEASE SEE PREVIOUS DISCUSSION BELOW FOR MORE
DETAILS...
PREVIOUS
AN UPPER TROUGH CONTINUES TO TRACK EASTWARDS INTO
WESTERN/CENTRAL NY AND PA, WHILE A 992 MB COASTAL LOW WILL
CONTINUE TO INTENSIFY AS IT TRACKS WELL EAST OF CAPE COD TODAY.
AN INVERTED TROUGH EXTENDS WESTWARDS FROM THE MAIN SFC LOW
TOWARDS THE UPPER TROUGH, AND WE ARE SEEING CONTINUED LIGHT SNOW
ACROSS MOST OF OUR FORECAST AREA NORTH OF THE INVERTED
TROUGH/AHEAD OF THE UPPER TROUGH AXIS. SO FAR, SNOWFALL RATES
HAVE GENERALLY BEEN UP TO AROUND A HALF INCH PER HOUR WITH
ISOLATED HALF TO THREE QUARTER INCH PER HOUR RATES WEST OF THE
CAPITAL DISTRICT OVER THE PAST FEW HOURS. LIGHT SNOW IS EXPECTED
TO CONTINUE THROUGH AROUND DAYBREAK THEN BEGIN TO TAPER TO SNOW
SHOWERS THROUGH MID-MORNING AS THE UPPER TROUGH AXIS SWINGS
THROUGH AND DRIER AIR WORKS ITS WAY INTO THE REGION.
THERE HAVE BEEN CONSISTENT SIGNALS FROM HI-RES GUIDANCE FOR A
PERIOD OF MOHAWK HUDSON CONVERGENCE (MHC) EARLY THIS MORNING
AROUND THE CAPITAL DISTRICT. THIS SETUP IS A GOOD MATCH TO THE
CONCEPTUAL MODEL DEVELOPED THROUGH COLLABORATIVE CSTAR RESEARCH
WITH SUNY ALBANY, AND WE ARE ALREADY SEEING THIS OCCUR BASED ON
THE CONVERGENCE SIGNAL SEEN FROM NYS MESONET DATA. WITHIN THE
MHC BAND, SNOWFALL RATES OF A HALF TO THREE QUARTERS OF AN INCH
COULD RESULT IN AN ADDITIONAL QUICK INCH OR TWO OF SNOW THIS
MORNING. OVERALL, STORM TOTAL SNOWFALL AMOUNTS WILL GENERALLY BE
ON THE ORDER OF 1 TO 3 INCHES, WITH SOME LOCALIZED 3 TO 4 INCH
TOTALS POSSIBLE ACROSS THE HIGH TERRAIN OF THE EASTERN
CATSKILLS, AND HELDERBERGS, AND WESTERN PORTIONS OF THE CAPITAL
DISTRICT.
MOST AREAS SHOULD SEE THE SNOW END BY LATE THIS MORNING,
ALTHOUGH SOME CONTINUED LAKE EFFECT AND UPSLOPE-ENHANCED SNOW
WILL BE POSSIBLE INTO THIS AFTERNOON FOR THE HIGH TERRAIN AREAS.
WITH FROUDE NUMBERS BELOW 0.5, THE UPSLOPE SNOW IS EXPECTED TO
BE MORE ON THE UPSTREAM SIDE OF THE MOUNTAINS. A COLD FRONT
TRACKING THROUGH THE REGION LATE THIS MORNING AND EARLY
AFTERNOON WILL USHER A MUCH COLDER AIRMASS INTO THE REGION, AND
IT WILL BECOME BREEZY AS THE SURFACE LOW TO OUR EAST CONTINUES
TO STRENGTHEN AND A 1035 MB SURFACE HIGH BUILDS INTO THE GREAT
LAKES. TEMPERATURES SHOULD THEREFORE DROP AS WE HEAD THROUGH
THIS AFTERNOON INTO THE 10S (VALLEYS) TO SINGLE DIGITS (TERRAIN).
SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/
KEY MESSAGE:
- COLD WEATHER ADVISORIES ISSUED FOR PORTIONS OF THE SOUTHERN
ADIRONDACKS, EASTERN CATSKILLS, AND BERKSHIRES FROM MIDNIGHT
TONIGHT THROUGH 9 AM SUNDAY, AS WE HAVE HIGH CONFIDENCE IN
UNUSUALLY COLD TEMPERATURES AND WIND CHILLS DURING THIS
TIMEFRAME.
- HIGH CONFIDENCE ON A LIGHT SNOW EVENT MONDAY NIGHT INTO
TUESDAY, BUT EXACT SNOWFALL TOTALS WILL STILL NEED TO BE
REFINED OVER THE COMING DAYS.
DISCUSSION:
TONIGHT, WE WILL SEE STRONG COLD ADVECTION CONTINUING AS WE WILL
BE UNDER/JUST WEST OF THE UPPER TROUGH. 850 MB TEMPERATURES DROP
BELOW -20C IN THE ADIRONDACKS, RESULTING IN SURFACE TEMPERATURES
AS LOW AS 5 TO 10F BELOW 0. ELSEWHERE, TEMPERATURES WILL REACH
THE SINGLE DIGITS TO -5F. WITH CONTINUED BREEZY CONDITIONS, WIND
CHILLS LOOK TO REACH COLD WEATHER ADVISORY CRITERIA (-20F FOR
THE ADKS; -15F FOR THE CATSKILLS AND BERKSHIRES), AND THUS
HEADLINES WERE ISSUED FOR THESE AREAS IN COLLABORATION WITH
WFOS BTV, BGM, AND BOX. THERE WILL LIKELY BE SOME LINGERING LAKE
EFFECT CLOUDS AROUND TONIGHT IN THE WESTERN MOHAWK VALLEY AND
CATSKILLS WITH NW FLOW TRAJECTORIES, AND WHILE A FEW FLURRIES
HERE CAN'T BE RULED OUT, MOST OF THE AREA SHOULD BE DRY AS
SUBSIDENCE BUILDS IN.
SUNDAY THROUGH MONDAY...COLD WILL BE THE THEME FOR THIS TIME
PERIOD. THE COLDEST WIND CHILLS ARE EXPECTED TONIGHT INTO SUNDAY
MORNING, AS WINDS SHOULD DIMINISH THROUGH THE DAY SUNDAY AS THE
SURFACE HIGH BUILDS CLOSER TO OUR REGION, BECOMING CENTERED
OVERHEAD SUNDAY NIGHT. HIGHS SUNDAY REMAIN QUITE COLD, WITH
MOST AREAS TOPPING OUT IN THE 10S, WITH SOME HIGH TERRAIN AREAS
REMAINING IN THE SINGLE DIGITS. THE COLDEST TEMPERATURES OF THE
SEASON ARE EXPECTED SUNDAY NIGHT, AS THE COMBINATION OF A STRONG
SURFACE ANTICYCLONE OVERHEAD, CLEARING SKIES AS THE 850 MB
RIDGE AXIS MOVES OVERHEAD, LIGHT WINDS, AND SNOW COVER WILL LEAD
TO IDEAL RADIATIONAL COOLING CONDITIONS. GIVEN THIS SETUP, WE
UNDERCUT NBM LOWS BY SEVERAL DEGREES, WITH PORTIONS OF THE ADKS
HITTING -10F AND MOST OF THE REST OF THE REGION IN THE LOW
SINGLE DIGITS OR BELOW 0. HOWEVER, WINDS WILL BE CALM SO WIND
CHILLS ARE NOT EXPECTED TO BE AS COLD AS SATURDAY NIGHT. WITH
LARGE-SCALE SUBSIDENCE IN PLACE, DRY WEATHER CONTINUES THROUGH
THIS TIMEFRAME. MONDAY STARTS OFF COLD AND DRY, BUT WINDS SWITCH
TO THE SOUTHWEST AS THE SURFACE HIGH SLIDES OFF TO OUR EAST,
RESULTING IN WARM ADVECTION. TEMPERATURES WILL STILL BE WELL
BELOW NORMAL, BUT SHOULD BE WARMER THAN SUNDAY WITH MOST AREAS
IN THE 10S TO 20S. CLOUDS WILL INCREASE DURING THE AFTERNOON
AHEAD OF OUR NEXT CLIPPER SYSTEM, BUT MOST OF THE DAY REMAINS
DRY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...AN UPPER SHORTWAVE AND
ASSOCIATED WEAKENING SFC LOW WILL TRACK FROM THE GREAT LAKES
THROUGH UPSTATE NY INTO NORTHERN NEW ENGLAND MONDAY NIGHT INTO
TUESDAY, BRINGING A WIDESPREAD LIGHT SNOWFALL TO THE REGION.
MOISTURE LOOKS FAIRLY LIMITED AND THIS SYSTEM WILL BE
PROGRESSIVE, SO QPF AMOUNTS GENERALLY LOOK LIGHT. THIS LOOKS
LIKE A GENERAL 1-3" EVENT, WITH THE HIGHEST AMOUNTS ALONG AND
NORTH OF I-90. A STRENGTHENING WESTERLY LLJ MAY LEAD TO SOME
LAKE ENHANCEMENT ACROSS THE WESTERN MOHAWK VALLEY AND IN THE
WEST FACING SLOPES OF THE SOUTHERN GREENS. AREAS CLOSER TO THE
I-84 WILL SEE SNOWFALL AMOUNTS ON THE LOWER END OF THE SPECTRUM,
AS THE BEST UPPER FORCING WILL REMAIN TO THE NORTH. PRECIP SHOULD
BE ALL SNOW, EVEN FOR VALLEY AREAS AS TEMPERATURES WILL BE IN
THE 10S MONDAY NIGHT. VALLEY AREAS SOUTH OF ALBANY DO WARM INTO
THE 30S TUESDAY, BUT LIKELY NOT UNTIL AFTER PRECIP ENDS. SNOW
SHOWERS SHOULD END BY TUESDAY AFTERNOON OR EVENING, WITH DRY
CONDITIONS EXPECTED TUESDAY NIGHT AS HEIGHTS RISE ALOFT AND A
RIDGE OF HIGH PRESSURE BUILDS IN FROM THE N/NW. WITH THE SURFACE
HIGH BUILDING IN, TEMPERATURES SHOULD BE ON THE COOLER SIDE OF
GUIDANCE TUESDAY NIGHT, WITH LOWS IN THE SINGLE DIGITS ACROSS
THE ADIRONDACKS AND 10S ELSEWHERE.
LONG TERM /WEDNESDAY THROUGH FRIDAY/
KEY MESSAGES:
-MAINLY DRY WEATHER THROUGH THE EXTENDED PERIOD WITH TEMPERATURES
LEANING TOWARDS MODERATING SLIGHTLY ABOVE NORMAL BY THE LATE WEEK
DISCUSSION:
CLOSED UPPER LEVEL DISTURBANCE WILL BE LOCATED OFF THE COAST OF NEW
ENGLAND ON CHRISTMAS MORNING AND IT WILL BE DEPARTING EASTWARD
THROUGH THE DAY, WITH RISING HEIGHTS ACROSS OUR AREA. SURFACE HIGH
PRESSURE WILL BE LOCATED JUST NORTH OF THE AREA ACROSS QUEBEC. AS A
RESULT, CHRISTMAS WILL BE A DRY AND PARTLY TO MOSTLY SUNNY SKY.
DESPITE THE SUNSHINE AND RISING HEIGHTS, THE COOL NORTHERLY FLOW
WILL STILL KEEP TEMPERATURES IN THE LOWER TO MIDDLE 30S FOR MOST
VALLEY AREAS FOR HIGHS ON CHRISTMAS DAY.
WITH AN UPPER LEVEL RIDGE ESTABLISHING ITSELF ALONG THE EASTERN
SEABOARD, THURSDAY AND FRIDAY SHOULD FEATURE CONTINUED DRY WEATHER,
WITH MODERATING TEMPERATURES. ALTHOUGH MORNING LOWS WILL STILL BE
CHILLY IN THE TEENS AND 20S, HIGHS LOOK TO REACH THE MIDDLE TO UPPER
30S FOR BOTH THURSDAY AND FRIDAY IN VALLEY AREAS.
THE NEXT CHANCE FOR WIDESPREAD PRECIP MAY BE TOWARDS SATURDAY, AS AN
APPROACHING SHORTWAVE FROM THE WEST MAY TRY TO BREAK DOWN THE RIDGE
AND BRING SOME STEADY PRECIP. WITH THIS SYSTEM COMING FROM THE
SOUTHWEST AND FAIRLY MILD TEMPS IN PLACE ALOFT, ODDS LEAN TOWARDS P-
TYPE BEING RAIN WITH THIS SYSTEM, ALTHOUGH IT'S FAR OUT IN TIME SO
THINGS COULD CERTAINLY CHANGE AS IT GETS CLOSER IN TIME. HIGHS LOOK
TO BE AROUND 40 IN VALLEY AREAS ON SATURDAY, WITH 30S ACROSS THE
HIGH TERRAIN.
AVIATION /11Z SATURDAY THROUGH WEDNESDAY/
UPPER LEVEL TROUGH AXIS IS MOVING ACROSS THE REGION THIS MORNING.
SOME ADDITIONAL LIGHT SNOW, AIDED BY LOCAL TERRAIN INFLUENCES, IS
ONGOING ACROSS THE AREA AND WILL LINGER FOR THE NEXT HOUR OR TWO.
THIS WILL RESULT IN IFR VISIBILITY, ESPECIALLY FOR KALB/KPOU,
THROUGH ABOUT 13Z OR 14Z.
SNOW WILL TAPER OFF TOWARDS MID-MORNING OR SO AS THE UPPER LEVEL
SHORTWAVE MOVES EASTWARD. WILL CONTINUE TO MENTION A VCSH FOR A FEW
HOURS IN CASE A FEW SNOW SHOWERS LINGER AROUND (ESPECIALLY NEAR
KALB), BUT VISIBILITY WILL BE IMPROVING. NORTHWEST WINDS WILL BE
PICKING UP BEHIND THE DEPARTING SYSTEM WITH SUSTAINED WINDS AROUND
10-15 KTS. THESE WINDS WILL PEAK IN THE LATE MORNING THROUGH LATE
AFTERNOON HOURS, WITH SOME GUSTS UP TO 25 KTS POSSIBLE, ESPECIALLY
AT KALB/KPSF. FLYING CONDITIONS WILL GO BACK TO VFR BY THE MID TO
LATE MORNING HOURS AS CEILINGS IMPROVE BACK TO AROUND 3500-5000 FT.
CLOUDS WILL DECREASE, WITH A MOSTLY CLEAR TO CLEAR SKY BY EVENING
INTO TONIGHT. VFR CONDITONS ARE EXPECTED FOR ALL OF TONIGHT. WINDS
WILL DECREASE SLIGHTLY, BUT STILL REMAIN BREEZY AROUND 10 KTS FROM A
NORTHWESTERLY DIRECTION INTO TONIGHT.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHSN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
CHRISTMAS DAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...MAIN
NEAR TERM...MAIN
SHORT TERM...MAIN/SPECIALE
LONG TERM...FRUGIS
AVIATION...FRUGIS
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