877
FXUS61 KALY 210544
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1244 AM EST THU NOV 21 2024
SYNOPSIS
A WEATHER SYSTEM BRINGING WIDESPREAD RAINFALL BEGINS TONIGHT THAT
CONTINUES INTO THE END OF THE WORK WEEK. IN THE SOUTHEAST AND
CENTRAL CATSKILLS AND SOUTHERN ADIRONDACKS, RAIN TRANSITIONS
OVER TO SNOW THURSDAY EVENING. BY SATURDAY MORNING, MOST
LOCATIONS BECOME DRY WITH A FEW LINGERING SNOW SHOWERS IN THE
SOUTHERN ADIRONDACKS, CENTRAL AND SOUTHEAST CATSKILLS AS OUR
WEATHER SYSTEM MOVES NORTHWARD. COOL TEMPERATURES CONTINUE
THROUGH THIS WEEKEND.
NEAR TERM /UNTIL 6 AM THIS MORNING/
UPDATE...AS OF 12:45 AM EST
CLOUDS CONTINUE TO INCREASE
ACROSS THE REGION, WITH THE LEADING EDGE OF THE RAIN RIGHT ON
THE DOORSTEP BETWEEN ALONG OUR CWA BORDER WITH WFO BGM. BASED ON
CURRENT TEMPERATURES(WHICH WERE RUNNING A FEW DEGREES ABOVE THE
PREVIOUS FORECAST) AND DEW POINTS, PRECIP SHOULD BEGIN AS ALL
RAIN, BUT SOME WET SNOW COULD BEGIN TO MIX IN ACROSS THE HIGHER
TERRAIN AREAS TOWARDS DAYBREAK, ALTHOUGH LITTLE TO NO
ACCUMULATION IS EXPECTED. OTHERWISE, PREVIOUS FORECAST REMAINS
IN GOOD SHAPE WITH MORE DETAILS BELOW...
PREVIOUS
CLOUDS CONTINUE TO INCREASE THIS EVENING AS A LOW
PRESSURE SYSTEM CONTINUES TO MOVE NORTHWARD ALONG THE ATLANTIC
COAST. TEMPERATURES TONIGHT REMAIN ABOVE FREEZING DUE TO THE
INCREASED CLOUDS, WITH LOWS IN THE UPPER 30S AND 40S.
FOR TONIGHT, HIGH RESOLUTION AND ENSEMBLE FORECAST MODEL
GUIDANCE IS IN GOOD AGREEMENT FOR THE ONSET TIMING OF RAINFALL
TO BEGIN FOR EASTERN NEW YORK AND WESTERN NEW ENGLAND TONIGHT.
BETWEEN 1 AM AND 5 AM EST, RAIN BEGINS TO MOVE FROM WEST TO EAST
THAT CONTINUES INTO THE DAY TOMORROW. RAINFALL COULD BE
PERIODICALLY MODERATE TO HEAVY IN SOUTHERN ULSTER AND DUTCHESS
COUNTIES.
SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/
*WINTER WEATHER ADVISORY ISSUED FOR WESTERN GREENE AND WESTERN
ULSTER COUNTIES FROM 4 PM THURSDAY THROUGH 1 AM SATURDAY*
KEY MESSAGES:
- RAIN CONTINUES THROUGH FRIDAY.
- RAIN TRANSITIONS TO SNOW THURSDAY NIGHT IN THE HIGH TERRAIN OF
THE GREENS, SOUTHERN ADIRONDACKS, AND SOUTHEAST AND CENTRAL
CATSKILLS WHERE THE CATSKILLS ARE FAVORED TO SEE THE MOST
SNOWFALL WITH THIS STORM.
THURSDAY... WIDESPREAD RAIN CONTINUES FOR EASTERN NEW YORK AND
WESTERN NEW ENGLAND. RAINFALL COULD BE PERIODICALLY MODERATE TO
HEAVY DURING THE MORNING HOURS AS THE CENTER OF THE LOW PRESSURE
SYSTEM CONTINUES TO MOVE UP THE ATLANTIC COAST. THIS IS WHERE
THE MY FORECAST CONFIDENCE BECOMES UNCERTAIN, HOW FAR WEST AND
INLAND DOES THE CENTER OF THE LOW GO. FORECAST MODELS ARE
FAVORING IT AT THIS FORECAST TIME TO PIVOT OVER CENTRAL NEW YORK
FOR THURSDAY NIGHT INTO FRIDAY MORNING WHERE THIS COULD BRING
WET AND HEAVY SNOWFALL ACROSS THE HIGHEST ELEVATIONS OF CENTRAL
AND SOUTHEAST CATSKILLS. THIS CAN'T BE STRESSED ENOUGH THAT THE
SNOWFALL IS GOING TO BE HIGHLY ELEVATION DEPENDENT. ELEVATIONS
ABOVE 3000 FEET (FOR EXAMPLE THE MOUNTAIN PEAKS OF THE
CATSKILLS) COULD SEE SNOWFALL AMOUNTS BETWEEN 6 AND 12 INCHES.
AS YOU GO LOWER IN ELEVATION IN THE CATSKILLS (BELOW 2500 FEET
IN ELEVATION), WARMER AIR TEMPERATURES COULD ALLOW RAIN TO
PERSIST LONGER BEFORE TRANSITIONING OVER TO SNOW WHERE 2 TO 6
INCHES IS FORECASTED. IF FUTURE FORECAST MODELS SHOW A SHIFT TO
THE WEST OR SOUTH OF THE CENTER OF THE LOW PRESSURE SYSTEM,
LOWER OR HIGHER SNOWFALL AMOUNTS COULD OCCUR. AS CURRENT
SNOWFALL AMOUNTS CONTINUE TO BE LOWER THAN WARNING CRITERIA FOR
THE POPULATED CITIES IN WESTERN ULSTER AND GREENE COUNTIES, WE
KEPT THE WINTER WEATHER ADVISORY FOR THESE LOCATIONS AS
SLIPPERY CONDITIONS WILL OCCUR THURSDAY NIGHT INTO FRIDAY
MORNING.
RAINFALL AMOUNTS ARE BETWEEN 1 INCH AND 2 INCHES WIDESPREAD FROM
TONIGHT THROUGH SATURDAY MORNING AS CONFIDENCE IS HIGH (GREATER
THAN 75 PERCENT) ACROSS EASTERN NEW YORK AND WESTERN NEW
ENGLAND FOR LOCATIONS TO EXPERIENCE THIS AS LATEST NATIONAL
BLEND OF MODELS DATA 4.2 HAS HIGH PROBABILITIES FOR GREATER THAN
1 INCH OF RAINFALL FOR 48 HOUR TOTALS.
FOR TOMORROW AFTERNOON, HIGH RESOLUTION FORECAST MODELS ARE
SUGGESTING A BRIEF BREAK IN THE PRECIPITATION FROM THE GREATER
CAPITAL DISTRICT TO THE LAKE GEORGE-SARATOGA REGION. THIS IS WHY
RAINFALL AMOUNTS HAVE LOWERED FOR THESE AREAS TO BETWEEN 0.5
INCHES AND 1.5 INCHES. WHAT WE CALL A DRY SLOT COULD OCCUR
DURING TOMORROW AFTERNOON WHICH GIVES US THIS BRIEF BREAK IN THE
PRECIPITATION. RAIN DOES RETURN FOR THURSDAY NIGHT THROUGH
FRIDAY MORNING.
FRIDAY AND SATURDAY...THE SURFACE LOW PRESSURE SYSTEM DEPARTS
OUR AREA FROM WEST TO EAST FRIDAY. A FEW LINGERING RAIN SHOWERS
AND HIGHER ELEVATION SNOW SHOWERS COULD OCCUR FRIDAY INTO
SATURDAY. TEMPERATURES FRIDAY MORNING COOL TO THE MID 30S FOR
VALLEYS AND INTO THE 20S FOR MOUNTAINOUS TERRAIN. FOR HIGH
TEMPERATURES FRIDAY, HIGHER TERRAIN LOCATIONS STRUGGLE TO REACH
ABOVE FREEZING BASED ON LATEST FORECAST GUIDANCE SO HIGHS ARE
FORECASTED IN THE LOW 30S. FOR SATURDAY, DRY CONDITIONS RETURNS
FROM SOUTH TO NORTH ACROSS EASTERN NEW YORK AND WESTERN NEW
ENGLAND AS OUR WEATHER SYSTEM DEPARTS TO THE EAST.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
THE VERTICALLY STACKED LOW PRESSURE SYSTEM MOVES FROM NEAR NEW
BRUNSWICK TO THE CANADIAN MARITIMES TO CLOSE THE WEEKEND. NORTH
TO NORTHWEST FLOW CONTINUES ALOFT OVER NY AND NEW ENGLAND. A
SFC TROUGH ROTATING AROUND THE OCCLUDED CYCLONE WILL FOCUS SOME
ISOLATED TO SCATTERED SNOW SHOWERS OVER THE WESTERN ADIRONDACKS
WITH SOME ISOLATED TO SCATTERED SNOW TO RAIN SHOWERS OVER THE
WESTERN AND CENTRAL MOHAWK VALLEY. IT WILL REMAIN BRISK AND
CHILLY IN THE CYCLONIC FLOW. MAX TEMPS WILL BE IN THE 30S TO
LOWER 40S OVER THE HILLS AND MTNS AND MID AND UPPER 40S IN THE
VALLEYS. THE SCATTERED SNOW SHOWERS AND FLURRIES DIMINISH SUNDAY
NIGHT WITH ONLY LIGHT ACCUMS EXPECTED OVER THE ADIRONDACK PARK.
LOWS FALL BACK INTO THE MID 20S TO LOWER 30S.
SOME FLAT MID AND UPPER LEVEL RIDGING BUILDS IN OVER THE REGION ON
MONDAY. HOWEVER, A LOW PRESSURE SYSTEM APPROACHES FROM THE
MIDWEST AND LOWER GREAT LAKES REGION. MID AND UPPER LEVEL
DIFFLUENT FLOW SETS UP OVER THE FORECAST AREA. CLOUDS WILL BE
THICKENING AND LOWER AS WARM ADVECTION INCREASES AHEAD OF THE
WARM FRONT. NBM PROBABILISTIC GUIDANCE INDICATES 25-50% CHANCES
FOR A MIXTURE OF LIGHT RAIN/SNOW TO OVERSPREAD THE REGION MONDAY
NIGHT INTO TUESDAY. THE BEST CHANCE FOR LIGHT SNOW ACCUMS WILL
BE OVER THE HIGHER TERRAIN AND NORTH/NORTHWEST OF THE CAPITAL
REGION MONDAY NIGHT INTO TUESDAY. MAX TEMPS WILL RUN A LITTLE
ABOVE NORMAL ON MONDAY IN THE UPPER 40S TO LOWER 50S IN THE
VALLEY AREAS AND UPPER 30S TO MID 40S OVER THE HIGHER TERRAIN.
TEMPS MONDAY NIGHT WILL BE OF THE WET BULB VARIETY IN THE UPPER
20S TO MID 30S. THE PRECIPITATION TRANSITIONS TO RAIN DURING THE
DAY TUESDAY WITH CONTINUED HIGH CHANCE TO LIKELY POPS. TEMPS
WILL GENERALLY IN THE 40S TO LOWER 50S. SOME UPPER 30S ARE
POSSIBLE OVER THE NORTHERN MTNS.
A COLD FRONT MOVES THROUGH TUESDAY NIGHT INTO WEDNESDAY WITH SOME
ISOLATED TO SCATTERED RAIN TO SNOW SNOW SHOWERS. THE BEST
CHANCE FOR SNOW SHOWERS WILL BE OVER THE WEST FACING SLOPES OF
THE ADIRONDACKS, SOUTHERN GREENS AND BERKSHIRES. TEMPS COOL DOWN
TO SEASONABLE READINGS AND IT WILL BE BRISK WITH CYCLONIC FLOW
PERSISTING. THE LATEST CPC DAY 8 TO 14 FORECAST 27 NOV TO 3 DEC
FOR EASTERN NY AND WESTERN NEW ENGLAND IS FOR NEAR NORMAL TEMPS
AND SLIGHTLY ABOVE NORMAL PRECIPITATION.
AVIATION /06Z THURSDAY THROUGH MONDAY/
THROUGH 06Z FRIDAY...MOST SITES TO SEE VFR INITIALLY, BUT THIS WILL
BEGIN TO CHANGE OVER THE NEXT SEVERAL HOURS AS A SYSTEM BRINGS A
STEADY RAIN ACROSS THE REGION. EXPECT CONDITIONS TO DETERIORATE WITH
THE RAIN'S ARRIVAL, WITH MVFR/IFR CEILINGS AND VISIBILITIES EXPECTED
BY DAYBREAK. THESE CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF
THE PERIOD AT ALL TERMINALS AS THE SYSTEM SLOWLY TRAVERSES THE AREA.
LIGHT & VARIABLE WINDS INITIALLY WILL INCREASE OUT OF THE EAST TO
NORTHEAST AROUND 10 KTS AFTER DAYBREAK, AND WILL SHIFT TO THE
NORTHWEST MAINLY AT KPOU/KALB AS THE SURFACE LOW NEARS THE TERMINALS
LATE IN THE PERIOD. KPSF WILL ALSO SEE LLWS LATE IN THE PERIOD WITH
A 40-50 KT LLJ PASSING NEAR THE TERMINAL.
OUTLOOK...
THURSDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY RA.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SATURDAY: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHRA.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. WINDY WITH GUSTS TO 31 KTS. NO SIG WX.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. BREEZY. NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 1 AM EST
SATURDAY FOR NYZ058-063.
MA...NONE.
VT...NONE.
SYNOPSIS...WEBB
NEAR TERM...MAIN/PICARD/WEBB
SHORT TERM...WEBB
LONG TERM...WASULA
AVIATION...SPECK
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