094
FXUS61 KBUF 211140
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
640 AM EST SAT DEC 21 2024
SYNOPSIS
EXPANSIVE HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES WILL
GRADUALLY DRIFT SOUTHEAST AND CROSS OUR REGION BY SUNDAY. THIS WILL
RESULT IN DAY TO DAY IMPROVEMENT IN OUR OVERALL WEATHER... BUT IT
WILL DEFINITELY BE COLD WITH TEMPERATURES AVERAGING WELL BELOW
NORMAL. THE MERCURY ON SUNDAY WILL HAVE TROUBLE CLIMBING OUT OF THE
SINGLE DIGITS EAST OF LAKE ONTARIO...WHILE THE REMAINDER OF WESTERN
NEW YORK WILL NOT ESCAPE THE TEENS. LOOKING FURTHER AHEAD...A WEAK
STORM SYSTEM MONDAY NIGHT AND TUESDAY SHOULD BE ABLE TO GENERATE
ENOUGH NUISANCE SNOW TO SUPPORT A WHITE CHRISTMAS FOR MOST AREAS.
NEAR TERM /THROUGH SUNDAY/
A FULL LATITUDE LONGWAVE TROUGH CENTERED OVER QUEBEC WILL FEED SOME
OF THE COLDEST AIR THUS FAR THIS SEASON SOUTHWARDS ACROSS THE REGION
DURING THE COURSE OF THIS WEEKEND. H85 TEMPS OF -17 TO -20C WILL
KEEP THE LAKES ACTIVE FOR THE BULK OF THIS PERIOD...ESPECIALLY LAKE
ONTARIO WHERE SEVERAL MORE INCHES OF LIGHT SNOW ARE EXPECTED. THIS
AIRMASS WILL PUSH TEMPS SOME 10 TO 15 DEGREES BELOW NORMAL...AS
HIGHS TODAY WILL BE IN THE TEENS TO LOWER 20S. MERCURY READINGS ON
SUNDAY WILL HAVE TROUBLE CLIMBING OUT OF THE SINGLE DIGITS EAST OF
LAKE ONTARIO...WHILE THE REMAINDER OF WESTERN NEW YORK WILL NOT
ESCAPE THE TEENS. AS FOR THE DAY TO DAY DETAILS...INCLUDING THE
NUISANCE LAKE SNOWS...
A VERY COLD NORTH TO NORTHWEST FLOW OVER THE WIDE OPEN LAKES WILL
HELP TO MAINTAIN A WEALTH OF STRATO-CU CLOUD COVER OVER THE REGION
TODAY...ALTHOUGH THERE COULD BE SOME WELCOMED BREAKS OF SUNSHINE AT
TIMES OVER THE IAG FRONTIER AND ACROSS NORTHERN JEFFERSON COUNTY.
WHILE SOME LIGHT SNOW WILL BE POSSIBLE JUST ABOUT EVERYWHERE IN THE
REGION TODAY...NUISANCE LAKE SNOWS WILL BE FOCUSED SOUTHEAST OF BOTH
LAKES...AND IN PARTICULAR BETWEEN ROCHESTER AND WESTERN OSWEGO
COUNTY...INCLUDING THE WESTERN FINGER LAKES. A WINTER WEATHER
ADVISORY WILL REMAIN IN PLACE FOR THESE AREAS WHERE A COUPLE INCHES
OF FLUFF COULD ACCUMULATE TODAY. THIS WILL BE A MUCH MORE MUTED
RESPONSE THAN PREVIOUS EVENTS THIS SEASON...PRIMARILY BECAUSE OF A
LOW 5KFT SUBSIDENCE INVERSION THAT WILL SERIOUSLY LIMIT THE
CONVECTIVE DEPTH. SNOWFALL RATES WILL AVERAGE AROUND A QUARTER TO AT
MOST A HALF INCH AN HOUR WITH SLR IN THE VCNTY OF 20:1.
CANADIAN HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES TODAY
WILL EASE TO THE SOUTHEAST AND EDGE ITS WAY OVER OUR FORECAST AREA
DURING THE COURSE OF TONIGHT. THIS WILL SET THE STAGE FOR A VERY
COLD NIGHT...ALTHOUGH LAKE CLOUDS WILL PERSIST ACROSS THE WESTERN
COUNTIES WITH CONTINUED LIGHT SNOW FOUND BETWEEN ROCHESTER AND
WESTERN OSWEGO COUNTY. ANOTHER INCH OR TWO OF ACCUMULATION WILL BE
POSSIBLE IN THAT AREA. MINS TONIGHT WILL RANGE FROM AROUND 10 IN THE
AFOREMENTIONED LAKE SNOW AREA TO THE SINGLE DIGITS FOR THE REMAINDER
OF WESTERN NEW YORK TO THE MINUS SINGLE DIGITS ACROSS THE NORTH
COUNTRY. APPARENT TEMPERATURES OVER THE TUG HILL AND IN THE WESTERN
FOOTHILLS OF THE 'DACKS WILL BE AS LOW AS -15F.
THE LARGE AREA OF HIGH PRESSURE WILL DRIFT DIRECTLY ACROSS OUR
FORECAST AREA ON SUNDAY. THIS WILL GUARANTEE DRY WEATHER FOR THE
MAJORITY OF THE REGION...ALTHOUGH RESIDUAL NUISANCE LAKE SNOW
SHOWERS WILL BE FOUND SOUTHEAST OF LAKE ONTARIO INTO THE MIDDAY
HOURS WHEN WEAK WARM ADVECTION WILL FINALLY KILL OFF THE LAKE
RESPONSE. OUR PERSISTENT CLOUD COVER WILL START TO 'OPEN UP'...
MAINLY OUTSIDE OF THE AFOREMENTIONED LAKE SNOW SHOWER AREA. THE MAIN
THING TO KNOW ABOUT SUNDAY IS THAT IT WILL BE COLDEST DAY SO FAR
THIS SEASON WITH AFTERNOON TEMPERATURES RANGING FROM THE TEENS OVER
THE WESTERN COUNTIES TO BETWEEN 10 AND 15 IN THE NORTH COUNTRY.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
CENTER OF ARCTIC HIGH PRESSURE AND CORE OF COLDEST AIR START TO
SHIFT EAST OF THE AREA SUNDAY NIGHT, HOWEVER WITH A GOOD RADIATIONAL
COOLING SETUP AND FAIRLY FRESH SNOWPACK, TEMPERATURES WILL PLUMMET.
WILL CONTINUE TO AIM BELOW GUIDANCE ALL AREAS, HOWEVER COULD SEE
THOSE FAVORED AREAS ACROSS THE NORTH COUNTRY REALLY TANKING WITH
CENTER OF ARCTIC HIGH NEARBY CENTERED OVER EASTERN NY/WESTERN NEW
ENGLAND. LOWS BELOW ZERO AGAIN NORTH COUNTRY (POSSIBLY SOME MINUS
TEENS IN THOSE CLIMATOLOGICALLY FAVORED AREAS), WITH MAINLY SINGLE
DIGITS ELSEWHERE.
HIGH PRESSURE DRIFTS EAST INTO NEW ENGLAND MONDAY, BUT WILL KEEP
MAINLY DRY WEATHER INTACT FOR THE START OF THE NEW WORK WEEK,
ALTHOUGH A FEW SNOW SHOWERS WILL BE POSSIBLE ACROSS NORTHWESTERN
AREAS LATE IN THE DAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST.
WARM AIR ADVECTION WILL ENSUE AS A LOW LEVEL SOUTHERLY RETURN FLOW
SETS UP ON THE BACK SIDE OF THE HIGH ALLOWING TEMPERATURES TO
RECOVER QUITE NICELY. HIGHS WILL REACH INTO THE UPPER TEENS TUG
HILL/WESTERN DACKS, WITH MAINLY 20S ELSEWHERE. EVEN SOME LOWER 30S
POSSIBLE ACROSS THE LOWER TERRAIN FROM THE GENESEE VALLEY WESTWARD.
DRY WEATHER WILL END MONDAY NIGHT AS TWO SHORTWAVES CLOSE IN ON THE
FORECAST AREA. THIS PAIR OF SHORTWAVES WILL MERGE AS THEY APPROACH
FROM THE WEST AND NORTHWEST, PHASING INTO A POSITIVELY TILTED
LONGWAVE TROUGH THAT WILL CROSS THE LOWER GREAT LAKES LATER MONDAY
NIGHT AND TUESDAY MORNING. TWO WEAK ATTENDANT SURFACE LOWS WILL ALSO
CONSOLIDATE INTO ONE, THEN TRAVERSE EASTWARD AND CROSS THE FORECAST
AREA LATE MONDAY NIGHT THROUGH TUESDAY MORNING AS WELL, BRINGING
ANOTHER ROUND OF WIDESPREAD MAINLY LIGHT SNOW. MODELS ARE IN GOOD
AGREEMENT ON BOTH THE TRACK AND SLOW WEAKENING TREND OF THE SURFACE
LOW. SYSTEM TRACKS EAST ACROSS LAKE ONTARIO LATER MONDAY NIGHT, THEN
TAKES A SLIGHT SHIFT EAST-SOUTHEASTWARD ACROSS CENTRAL NY TUESDAY
MORNING BEFORE EXITING EAST OF OUR FORECAST AREA. WITH THIS TRACK,
AREAS JUST NORTH OF THE LOW TRACK EAST OF LAKE ONTARIO STAND THE
BEST CHANCES FOR SEEING AT LEAST A COUPLE/FEW INCHES OF SNOW,
ESPECIALLY ALONG THE SOUTHERN SLOPES OF THE TUG HILL WITH A
SOUTHERLY UPSLOPE FLOW IN PLACE. MUCH LESS SNOW WOULD FALL SOUTH OF
LAKE ONTARIO (SOUTH OF THE LOW TRACK). WITH THE BULK OF THE PRECIP
OCCURRING MONDAY NIGHT AND TUESDAY MORNING, EXPECT ALL AREAS TO SEE
MAINLY SNOW, ALTHOUGH MAY WARM ENOUGH ACROSS THE LOWER ELEVATIONS
SOUTH LAKE ONTARIO THAT ANY LINGERING PRECIP POSSIBLY MIXES WITH A
LITTLE RAIN BY TUESDAY AFTERNOON. A BRIEF PERIOD OF SOME
NORTHWESTERLY FLOW UPSLOPE SNOW LOOKS POSSIBLE LATER TUESDAY MORNING
INTO THE AFTERNOON, WITH HIGHER TERRAIN EAST OF LAKE ERIE LOOKING TO
HAVE THE MORE FAVORABLE SETUP. TEMPS ALOFT NOT NEARLY AS COLD BEHIND
THIS SYSTEM, WITH 850MB TEMPS -6C TO -8C, JUST MARGINALLY COLD
ENOUGH FOR A LAKE RESPONSE. ANY LAKE RESPONSE WOULD BE SHORT-LIVED
HOWEVER AS HIGH PRESSURE AND WARMING TEMPS ALOFT START TO MOVE IN
MID WEEK. NOT AS COLD MONDAY NIGHT WITH MAINLY 20S FOR LOWS, TEENS
NORTH COUNTRY. HIGHS TUESDAY RANGE FROM THE MID/UPPER 20S NORTH
COUNTRY TO THE LOW AND MID 30S ELSEWHERE.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
THE PATTERN ACROSS NORTH AMERICA WILL BECOME VERY NON-WINTER LIKE
DURING THE SECOND HALF OF NEXT WEEK AS ANOMALOUS WARMTH FLOODS THE
ENTIRE CONTINENT. A BROAD, FLAT RIDGE AND ABOVE NORMAL MID/UPPER
LEVEL HEIGHTS WILL SPREAD FROM COAST TO COAST AND ACROSS THE
SOUTHERN HALF OF CANADA. THIS WILL BRING AN EXTENDED PERIOD OF ABOVE
AVERAGE TEMPERATURES AND BENIGN WEATHER TO OUR REGION STARTING THE
SECOND HALF OF NEXT WEEK. IN FACT, MAINLY DRY WEATHER LOOKS POSSIBLE
FOR THE BULK OF THIS PERIOD, WITH THE NEXT AREA OF LOW PRESSURE NOT
PROGGED TO APPROACH UNTIL VERY LATE IN THE WORK WEEK.
TUESDAY NIGHT, THE LAST OF THE COLD AIR WILL STILL BE IN THE PROCESS
OF DEPARTING. THIS MAY STILL SUPPORT A FEW SCATTERED LIGHT SNOW
SHOWERS EAST OF THE LAKES IN UPSLOPE AREAS. HIGH PRESSURE WILL THEN
BUILD EAST ACROSS THE GREAT LAKES AND INTO NEW ENGLAND LATER TUESDAY
NIGHT THROUGH CHRISTMAS DAY, BRINGING A RETURN TO DRY WEATHER.
CLOUDS MAY LINGER MUCH OF THE DAY BENEATH A STEEPENING INVERSION,
AND TEMPERATURES WILL REMAIN NEAR AVERAGE THROUGH CHRISTMAS DAY.
THURSDAY THROUGH FRIDAY, A MID LEVEL RIDGE WILL CONTINUE TO BUILD
OVER THE OHIO VALLEY AND EASTERN GREAT LAKES, WITH CONTINUED WARM
ADVECTION ALLOWING TEMPERATURES TO CLIMB ABOVE AVERAGE. HIGH
PRESSURE WILL REMAIN NEARBY ALONG OR JUST OFF THE EAST COAST, WHICH
SHOULD KEEP MOST OF THE PRECIPITATION ASSOCIATED WITH A TROUGH OVER
THE CENTER OF THE NATION TO OUR WEST, POSSIBLY ALL THE WAY THROUGH
THE END OF THE WEEK.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
WE CAN ANTICIPATE THAT MVFR CIGS WILL PERSIST FOR MOST OF THE TAF
SITES THROUGH TODAY....ALTHOUGH A RETURN TO VFR WEATHER IS EXPECTED
AT KART. THE LOWER CIGS WILL BE ACCOMPANIED BY SOME LIGHT LAKE
SNOWS...ESPECIALLY SOUTHEAST OF BOTH LAKES WHERE SOME IFR VSBYS WILL
BE POSSIBLE.
MAINLY MVFR CIGS ARE THEN FORECAST FOR THE REGION TONIGHT WITH LESS
WIDESPREAD LAKE SNOWS...MAINLY BEING FOCUSED SOUTHEAST OF LAKE
ONTARIO.
OUTLOOK...
SUNDAY...MAINLY VFR BUT WITH AREAS OF MVFR CONDITIONS IN LIGHT LAKE
SNOWS BETWEEN KROC AND KSYR.
MONDAY...VFR.
TUESDAY...RESTRICTIONS POSSIBLE WITH RAIN/SNOW SHOWERS LIKELY.
WEDNESDAY...VFR.
MARINE
WIDESPREAD SMALL CRAFT ADVISORIES WILL REMAIN IN PLACE TODAY....AS
MODERATE TO FRESH NORTHERLIES WILL BACK TO THE NORTHWEST...COURTESY
OF A LARGE AREA OF CANADIAN HIGH PRESSURE THAT WILL APPROACH FROM
THE UPPER GREAT LAKES. WINDS WILL THEN SUBSIDE TONIGHT...AS THE AREA
OF HIGH PRESSURE WILL MAKE ITS WAY OVER THE LOWER GREAT LAKES. THIS
WILL ALLOW WINDS AND WAVES TO DROP BELOW SMALL CRAFT LEVELS.
LIGHT NORTHERLIES AND NEGLIGIBLE WAVES ARE EXPECTED FOR SUNDAY AS
THE AREA OF HIGH PRESSURE WILL BE DIRECTLY OVER THE REGION.
BUF WATCHES/WARNINGS/ADVISORIES
NY...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ004-005-014.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
LEZ041.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON
FOR LOZ030.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ042.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LOZ043>045.
SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JM
LONG TERM...HITCHCOCK/JM
AVIATION...RSH
MARINE...RSH
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