430
FXUS61 KBGM 212339
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
639 PM EST SUN DEC 21 2025
WHAT HAS CHANGED
LAKE EFFECT SNOW THIS AFTERNOON AND EARLY EVENING IS MORE
ORGANIZED THAN FORECAST. GREATER CONFIDENCE IN WIDESPREAD
ACCUMULATIONS OF SNOW MONDAY NIGHT INTO TUESDAY MORNING.
KEY MESSAGES
1) LAKE EFFECT SNOW PERSISTING THROUGH TONIGHT, MAINLY NORTH OF
THE THRUWAY.
2) CLIPPER SYSTEM PASSING THROUGH MONDAY NIGHT INTO TUESDAY
BRINGING SNOW AND MIXED PRECIPITATION TO THE REGION.
3) ADDITIONAL CLIPPER SYSTEMS INTO THE END OF THE WEEK; A
FAVORABLE PATTERN FOR POTENTIAL OVERRUNNING PRECIPITATION
EVENTS.
DISCUSSION
KEY MESSAGE 1...
A FAIRLY ROBUST LAKE EFFECT SNOW PLUME HAS DEVELOPED OFF OF LAKE
ONTARIO THIS AFTERNOON. THE BAND HAS NOT REALLY ORGANIZED BUT
DESPITE IT BEING MOSTLY CELLULAR, WEBCAMS ARE STILL SHOWING
HEAVY SNOW AND QUICK ACCUMULATIONS, ESPECIALLY AT CAMDEN NYSM
SITE. FORECAST SOUNDINGS SHOW THE MEAN BOUNDARY LAYER WINDS
REMAIN OUT OF THE WEST FOR A FEW MORE HOURS, THEN WINDS SHIFT TO
OUT OF THE NW. THIS SHOULD CAUSE THE BAND TO DROP MORE INTO THE
NY THRUWAY LATER THIS EVENING AND INTO TONIGHT. UPPER LEVEL
RIDGING WITH COLD AIR ADVECTION WEAKENING OVERNIGHT WILL ALSO
HELP KEEP THE LAKE EFFECT BAND MORE DIFFUSE OVERNIGHT AS IT
DROPS SOUTH SO ACCUMULATIONS REMAIN LIGHTER OVERNIGHT. CHANCES
OF SNOW WERE ALSO KEPT INTO THE EARLY MORNING AS THE 850 MB
RIDGE DOES NOT BUILD IN UNTIL AFTER 8 AM TOMORROW WITH WINDS
SHIFTING BACK SW AND THE 850 MB TEMPERATURES GETTING BACK ABOVE
-7C.
KEY MESSAGE 2...
A WEAK CLIPPER SYSTEM MOVING THROUGH THE NORTHERN GREAT LAKES
MONDAY NIGHT INTO TUESDAY ALONG WITH A RIDGE BUILDING BRINGS A
WARM FRONT INTO NY AND PA. OVERRUNNING PRECIPITATION MOVES IN
MONDAY NIGHT AND WITH PLENTY OF ANTECEDENT COLD AIR IN PLACE,
PRECIPITATION TYPES OVERNIGHT ARE EXPECTED TO BE ALL SNOW. QPF
AMOUNTS LOOK TO BE AROUND A QUARTER INCH AND SNOW RATIOS ARE
EXPECTED TO BE AROUND 10:1 AS TEMPERATURES WARM ALOFT AND NEAR
THE SURFACE TOWARDS FREEZING TUESDAY MORNING. RIGHT NOW,
WIDESPREAD 2 TO 3 INCHES OF SNOW IS EXPECTED, WITH LOWER AMOUNTS
LIKELY OVER NEPA INTO THE WESTERN SOUTHERN TIER WHERE THE
TEMPERATURES RISE TO NEAR FREEZING SO SOME MIXING TO RAIN IS
POSSIBLE.
LOOKING AT FORECAST SOUNDINGS, THERE IS A SMALL CHANCE OF
FREEZING RAIN LATE MONDAY NIGHT INTO EARLY TUESDAY JUST AS THE
PRECIPITATION IS WINDING DOWN. SURFACE TEMPERATURES REMAIN JUST
BELOW FREEZING IN PARTS OF THE SOUTHERN TIER AND EASTERN NEPA
WHILE TEMPERATURES ALOFT RISE JUST ABOVE FREEZING. THE MELT
LAYER IS SMALL SO COMPLETE MELTING MAY NOT HAPPEN AND
PRECIPITATION ENDS UP BEING MORE PARTIALLY MELTED SNOW TO A
SLEET MIXTURE RATHER THAN FREEZING RAIN. CONFIDENCE IN ITS
LOCATION AND IF IT WOULD EVEN HAPPEN OR NOT WAS TOO HIGH SO
FREEZING RAIN AND SLEET WERE REMOVED FROM THE GRIDS FOR NOW.
KEY MESSAGE 3...
THE UPPER LEVEL PATTERN IN THE NORTHERN HEMISPHERE LOOKS TO BE
BLOCKED WITH 3 LARGE RIDGES IN WESTERN ALASKA, THE CENTRAL US,
AND NORTHERN EUROPE. THIS MEANS THAT WE WILL BE STUCK ON THE
BACKSIDE OF A TROUGH OFF OF THE EASTERN US AND THE CENTRAL US
RIDGE LEADING TO PLENTY OF CHANCES OF CLIPPERS TO DRIVE OUT OF
THE NW INTO THE MID ATLANTIC. GIVEN THE AMOUNT OF WARM AIR IN
THE CENTRAL PLAINS AS WELL AS ACCESS TO COLD AIR IN EASTERN
CANADA, THE SET UP IS FAVORABLE FOR OVERRUNNING PRECIPITATION
EVENTS THROUGH CHRISTMAS WEEK AND INTO NEXT WEEKEND. RIGHT NOW,
THERE IS NO FREEZING RAIN OR SLEET IN THE FORECAST FOR WEDNESDAY
ONWARD, IF THERE CAN BE STRONG ENOUGH HIGH PRESSURE OVER
NORTHERN NEW ENGLAND DURING A PASSAGE OF A SHORTWAVE, THERE CAN
BE SOME LOW LEVEL COLD AIR ADVECTING IN WHILE WARM AIR ALOFT
MELTS THE PRECIPITATION SO THAT.
AVIATION /00Z MONDAY THROUGH FRIDAY/
- LAKE EFFECT SNOW TO IMPACT RME AND SYR THIS EVENING
A HEAVY LAKE EFFECT SNOW BAND ACROSS NORTHERN ONEIDA COUNTY WILL
DROP SOUTH THIS EVENING AND CAUSE RESTRICTIONS FOR A FEW HOURS
AT RME AND EVENTUALLY SYR. CONDITIONS ARE EXPECTED TO FLUCTUATE
BETWEEN MVFR AND LIFR AT RME THROUGH ABOUT 00-03Z BEFORE
SHIFTING SOUTH. THERE IS SOME UNCERTAINTY WITH HOW QUICKLY THE
SNOW SHOWERS DRIFT SOUTH INTO SYR THIS EVENING WITH THE TREND
CONTINUING TO BE SLOWER, GENERALLY AFTER 01Z NOW. THERE IS THE
POTENTIAL FOR MORE OF A DEFINED BAND TO DEVELOP FOR A FEW HOURS
THIS EVENING IF WE GET A MULTI-LAKE CONNECTION TO SET UP. AS
HIGH PRESSURE BEGINS TO BUILD IN OVERNIGHT AND THE LAKE EFFECT
SNOW WILL EVENTUALLY COME TO END, BUT CONFIDENCE REMAINS LOW ON
THE TIMING AND INTENSITY.
ITH AND BGM ARE BOTH EXPECTED TO SEE SOME MVFR CEILINGS DEVELOP
LATER TONIGHT AS THE LAKE EFFECT SNOW SHOWERS SHIFT SOUTH.
CONFIDENCE WAS TOO LOW TO BRING RESTRICTIONS FROM THE SNOW
SHOWERS AT THIS TIME HERE, BUT MVFR HAVE BEEN ADDED.
OUTLOOK...
MONDAY NIGHT...SNOW OVERSPREADS THE AREA ALONG WITH ASSOCIATED
RESTRICTIONS.
TUESDAY INTO TUESDAY NIGHT...OCCASIONAL RESTRICTIONS POSSIBLE
IN RAIN AND SNOW.
WEDNESDAY...MAINLY VFR.
THURSDAY...A LOW CHANCE OF RAIN AND SNOW SHOWERS AND ASSOCIATED
RESTRICTIONS.
FRIDAY...RAIN AND SNOW SHOWERS LIKELY ALONG WITH ASSOCIATED
RESTRICTIONS.
BGM WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ009.
DISCUSSION...AJG
AVIATION...DK/MPK
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