950
FXUS61 KALY 201817
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
117 PM EST SAT DEC 20 2025
WHAT HAS CHANGED
CONFIDENCE CONTINUES TO INCREASE IN A LIGHT TO MODERATE
SNOWFALL LATE MONDAY NIGHT THROUGH TUESDAY, AS A CLIPPER SYSTEM
MOVES ACROSS THE REGION.
KEY MESSAGES
1. A COLD FRONT WILL BRING SOME SNOW SHOWERS TO MAINLY HIGHER
TERRAIN AREAS LATE TONIGHT INTO SUNDAY MORNING. THIS WILL BE
FOLLOWED BY A PERIOD OF LAKE EFFECT SNOW SUNDAY AFTERNOON IN THE
WESTERN MOHAWK VALLEY AND SOUTHWEST ADIRONDACKS, WITH GUSTY
NORTHWEST WINDS DEVELOPING ACROSS THE AREA.
2. CONFIDENCE CONTINUES TO INCREASE IN THE POTENTIAL FOR A
LIGHT TO MODERATE SNOWFALL LATE MONDAY NIGHT THROUGH TUESDAY,
WHICH COULD IMPACT BOTH THE MORNING AND EVENING COMMUTES AS WELL
AS ANY PRE- HOLIDAY TRAVEL.
3. TEMPERATURES CONTINUE TO TREND ABOVE NORMAL FOR LATER NEXT
WEEK, WITH SOME CHANCES FOR MAINLY RAIN WITH SOME HIGH ELEVATION
WINTRY PRECIPITATION POSSIBLE AT TIMES.
DISCUSSION
KEY MESSAGE 1...
AS LOW PRESSURE TRACKS EAST FROM ONTARIO INTO QUEBEC LATE
TONIGHT INTO SUNDAY MORNING, THE SYSTEM'S COLD FRONT WILL PUSH
SOUTHEAST ACROSS OUR AREA. THERE IS LIMITED MOISTURE WITH THIS
SYSTEM, SO ONLY ISOLATED TO SCATTERED SNOW SHOWERS ARE EXPECTED
AND MAINLY ACROSS HIGHER TERRAIN AREAS.
AFTER THE COLD FRONT MOVES THROUGH, COLDER AIR ALOFT WILL
FILTER IN RESULTING IN LAKE EFFECT SNOW DEVELOPING DUE TO
CONDITIONAL LAKE INDUCED INSTABILITY AND A W-NW FLOW. THE ~290
DEGREE TRAJECTORY FAVORS THE SW. ADIRONDACKS AND W. MOHAWK
VALLEY SUN AFTERNOON INTO EARLY EVENING, WHERE 1-3" OF SNOW
COULD ACCUMULATE WHERE THE MOST PERSISTENT BANDS OCCUR. OUTSIDE
OF THE LAKE EFFECT, NW WINDS WILL INCREASE WITH GUSTS OF 25-35
MPH DEVELOPING IN MOST AREAS. TEMPERATURES WILL LIKELY PEAK LATE
MORNING TO EARLY AFTERNOON, THEN FALLING THE REST OF THE DAY.
LAKE EFFECT SNOW WILL DIMINISH SUN EVENING AS THE FLOW VEERS TO
305 DEGREES, LIMITING TO CENTRAL NY.
KEY MESSAGE 2...
LATE MON NIGHT INTO TUE, A CLIPPER SYSTEM QUICKLY APPROACHES
FROM THE UPPER GREAT LAKES AND SE CANADA IN A FAST NW FLOW
REGIME. THIS LOOKS TO BE A PROGRESSIVE, BUT FAIRLY VIGOROUS
SYSTEM. THERE IS STILL UNCERTAINTY IN THE TRACK OF THE SURFACE
CYCLONE, WITH THE ECWMF ENSEMBLES SHOWING THE CYCLONE CENTER
TRACKING NORTH OF OUR AREA, WHILE THE GFS ENSEMBLES INDICATE
MORE OF A SOUTHERLY TRACK OVER OUR AREA. A SOUTHERLY TRACK WOULD
RESULT IN A COLDER/SNOWIER SCENARIO, BUT EVEN THE NORTHERLY
TRACK WOULD RESULT IN AT LEAST SOME ACCUMULATING SNOW, BUT
TURNING MILDER TUE P.M. (35-40F) FAVORING SNOW MIXING WITH RAIN
IN LOWER ELEVATIONS. WILL STAY CLOSER TO THE NBM FOR NOW, BUT
ACCOUNT FOR WETBULB EFFECT AND LEANING SLIGHTLY SNOWIER TUE P.M.
FORCING FROM ISENTROPIC LIFT AND A SHORT WAVE ALOFT WILL LEAD
TO A PERIOD OF SNOW LATE MON NIGHT THROUGH AT LEAST TUE MORNING.
THE TUE P.M. TIMEFRAME IS LESS CERTAIN DUE TO POSSIBLE PTYPE
ISSUE OF RAIN MIXING WITH SNOW IN LOWER ELEVATIONS. CONFIDENCE
SHOULD INCREASE AS THE SYSTEM GETS CLOSER OVER THE NEXT FEW
DAYS. AT THIS TIME WILL MENTION PRELIMINARY SNOW AMOUNTS OF 2-4"
IN VALLEYS WITH 3-6" IN THE HIGHER TERRAIN. GREATEST AMOUNTS IN
FAVORED UPSLOPE AREAS OF THE SW ADIRONDACKS. LATEST 24-HR NBM
PROBS FOR SNOWFALL INDICATE A 45-85% CHANCE FOR > 2" (GREATEST
IN THE MOUNTAINS) AND A 30-50% CHANCE FOR > 4" IN THE HIGHER
TERRAIN. WILL CONTINUE TO MONITOR TRENDS FOR A POSSIBLE WINTER
WEATHER ADVISORY ISSUANCE IF CONFIDENCE CONTINUES TO INCREASE.
KEY MESSAGE 3...
AFTER A PERIOD OF SEASONABLY COOL TEMPERATURES CHRISTMAS EVE
THROUGH CHRISTMAS DAY, TEMPERATURES LOOK TO TREND ABOVE BY LATE
WEEK. ANOTHER POTENTIAL CLIPPER SYSTEM COULD BRING PRECIPITATION
IN LATE CHRISTMAS DAY TO FRI TIMEFRAME, WITH NBM INDICATING
MAINLY RAIN AT THIS TIME. HOWEVER, DEPENDING ON TIMING AND THE
EVENTUAL TRACK OF THE CLIPPER THERE COULD BE SOME WINTRY PRECIP,
ESPECIALLY AT HIGHER ELEVATIONS. CONFIDENCE IS LOW AT THIS
TIME. WILL MONITOR TRENDS AS POST-HOLIDAY TRAVEL COULD BE
AFFECTED.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
VFR CONDITIONS CONTINUE THROUGH THE TAF PERIOD FOR ALL TAF
SITES. PASSING MID-LEVEL CLOUDS ARRIVE LATER THIS AFTERNOON INTO
THIS EVENING. LIGHT AND VARIABLE WINDS INCREASE LATER TONIGHT
TO BETWEEN 5 AND 10 KNOTS. WINDS ALSO CHANGE DIRECTION DURING
THE MORNING HOURS FROM SOUTHERLY TO WESTERLY. WIND GUSTS ALSO
INCREASE FOR TOMORROW MORNING INTO THE END OF THE TAF PERIOD
RANGING BETWEEN 20 AND 28 KNOTS AT KPSF, KALB, AND KGFL. LOW
LEVEL WIND SHEAR MENTION IN THE TAFS CONTINUE FOR THE OVERNIGHT
HOURS TONIGHT AT KPOU FOR UP TO 35 KNOT WINDS AT 2 KFT, BUT
CONFIDENCE IS LOWER TO INCLUDE MENTION AT KPSF AND KALB FOR
AFTER 00Z TONIGHT. BUT, CONFIDENCE COULD INCREASE ONCE AGAIN
WITH THE NEXT FORECAST AND ADDED BACK IN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. BREEZY. NO SIG WX.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SN.
TUESDAY: HIGH OPERATIONAL IMPACT. DEFINITE RA...SN.
TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF RA...SN.
WEDNESDAY: LOW OPERATIONAL IMPACT. BREEZY. NO SIG WX.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
CHRISTMAS DAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
DISCUSSION...07
AVIATION...05
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page