370
FXUS61 KCTP 230400
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1100 PM EST SUN DEC 22 2024
SYNOPSIS
HIGH PRESSURE DRIFT EAST ACROSS THE ADIRONDACKS TONIGHT. A WEAK
AREA OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL TRACK NORTH
OF THE STATE MONDAY NIGHT INTO EARLY CHRISTMAS EVE. A PAIR OF
WEAKENING SHORTWAVES ARE LIKELY TO RIDE THE NORTHERN PERIPHERY
OF A BUILDING RIDGE OVER PA THE SECOND HALF OF NEXT WEEK, AS A
LARGE SURFACE HIGH REMAINS ANCHORED NORTH OF NEW ENGLAND.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
RIDGE OF SFC HIGH PRESSURE OVER THE REGION TONIGHT WILL
SUPPORT MAINLY CLEAR SKIES AND LIGHT WIND. ALONG WITH FRESH
SNOW COVER ACROSS THE REGION, IDEAL RADIATIONAL COOLING
CONDITIONS WILL LEAD TO VERY COLD TEMPERATURES. DAYBREAK MONDAY
MINS OF A FEW TO SEVERAL DEG F BELOW ZERO ARE LIKELY IN THE
PERENNIAL COLD SPOTS UP NORTH. TEMPERATURES ACROSS THE NORTHERN
TIER ARE ALREADY TRENDING BELOW EXPECTATION TONIGHT. IN THE NWS
BINGHAMTON FORECAST AREA, WHICH IS DIRECTLY UNDER THE HIGH,
TEMPERATURES ARE ALREADY TRENDING BELOW THE 5TH PERCENTILE OF
THE NATIONAL BLEND OF MODELS.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
A RETURN SOUTHEAST TO SOUTHERLY FLOW BEHIND THE DEPARTING
SURFACE HIGH WILL HELP TEMPERATURES REBOUND SLIGHTLY ON MONDAY
AS HIGH, THEN THICKENING MID CLOUDS STREAM IN FROM THE WEST AHEAD
OF AN UPSTREAM SHORTWAVE OVER THE W GRT LKS. GEFS 2M TEMPS
INDICATE MAX TEMPS WILL REMAIN SEVERAL DEGREES BELOW AVERAGE.
THE SHORTWAVE AN ASSOCIATED WEAK SFC LOW IS PROGGED TO PASS
JUST NORTH OF THE REGION MONDAY NIGHT INTO EARLY TUESDAY. THE
STRONGEST FORCING WITH THIS FEATURE SHOULD REMAIN NORTH OF THE
AREA AND MOISTURE RETURN ALONG THE ATTENDANT LOW LEVEL JET IS
UNIMPRESSIVE. STILL, PERIODS OF WEAK UVVEL WILL PRODUCE AREAS OF
LIGHT SNOW/SNOW SHOWERS LATE MONDAY/MONDAY NIGHT.
A COATING OF SNOW IS LIKELY NEAR THE ALLEGHENY FRONT WHILE
UP TO A COUPLE INCHES ARE POSSIBLE ACROSS THE NW MTNS AS SOME
ADDED MOISTURE FROM LAKE ERIE IS INJECTED INTO THE REGION POST
COLD FRONTAL EARLY CHRISTMAS EVE. THE SOUTHERN VALLEYS AND SUSQ
REGION COULD SEE A LIGHT ACCUMULATION OF SNOW BEFORE DAYBREAK. MODEL
SOUNDINGS INDICATE THERE IS SOME RISK FOR A BIT OF VERY LIGHT
FREEZING RAIN OVER THE LOWER SUSQ VALLEY AROUND DAYBREAK
TUESDAY. HIGHEST PROBABILITY IS CURRENTLY ALONG AND SOUTHEAST OF
THE US-30 CORRIDOR THROUGH YORK AND LANCASTER COUNTIES.
THE BEST FORCING AND DEEPEST MOISTURE SHOULD HAVE PASSED PA BY
LATE TUESDAY MORNING LIKELY LEAVING A FAIRLY EXTENSIVE DECK OF
GENERALLY NON-PRECIPITATING STRATOCU. THIS RESIDUAL LOW LEVEL
MOISTURE ASCENDING THE ALLEGHENIES COULD RESULT IN SPOTTY VERY
LIGHT SNOW/DRIZZLE INTO THE AFTERNOON OVER THE WESTERN PART OF
THE FORECAST AREA.
DRY CONDITIONS WITH LIGHT WIND AND VARYING AMOUNTS OF STRATO CU
AND CIRRUS WILL SUPPORT GOOD/COMFORTABLE FLIGHT CONDITIONS
FOR SANTA'S PERIOD OF HEAVY WORKLOAD LATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH TEMPS RANGING THROUGH THE 20S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ON THE LARGE-SCALE, THE AMPLIFIED, COLD EASTERN
CANADIAN/NORTHEASTERN CONUS UPPER TROUGH DOMINATING AT THE
PRESENT TIME SHOULD BE A THING OF THE PAST BY CHRISTMAS DAY, AS
THIS FEATURE LIFTS OUT INTO THE NORTHERN ATLANTIC. IT WILL
REPLACED BY BUILDING HEIGHTS AND A GENERALLY MORE ZONAL FLOW
PATTERN ALOFT. THIS TRANSLATES INTO MORE SEASONABLE TEMPERATURES
FOR LATE DECEMBER ACROSS PA, EVEN TRENDING ABOVE CLIMO TOWARDS
NEXT WEEKEND.
AS FOR THE SENSIBLE WEATHER, THERE IS INCREASING CONFIDENCE THAT
SURFACE HIGH PRESSURE FROM SOUTHEASTERN CANADA DOWN INTO THE
NORTHEASTERN U.S. WILL KEEP THE WEATHER DRY FOR THE COMMONWEALTH
FROM CHRISTMAS DAY THROUGH FRIDAY. UNCERTAINTY GROWS INTO THE
WEEKEND, AS LOW- LEVEL EASTERLY FLOW AND THE APPROACH OF WEAK
SHORT- WAVE ENERGY FROM THE MIDWEST COULD BRING BOUTS OF LIGHT
PRECIPITATION, ESPECIALLY FOR SOUTHERN AND WESTERN SECTIONS OF
THE STATE. AT THIS EARLY JUNCTURE, LIGHT RAIN APPEARS TO BE THE
MOST PROBABLE PRECIPITATION TYPE, BUT POCKETS OF LIGHT WINTRY
MIX ARE NOT OUT OF THE QUESTION.
AVIATION /04Z MONDAY THROUGH FRIDAY/
VFR (MAINLY SKC) EXPECTED AT ALL TAF SITES THROUGH TONIGHT AND
LIKELY ALL OF THE DAYLIGHT HOURS MONDAY AS WELL AS A RIDGE OF
HIGH PRESSURE EXTENDING SOUTH ACROSS CENTRAL PA SLIDES SLOWLY TO
THE EAST.
A THICKENING LAYER OF MID LEVEL CLOUDS AOA 10KFT AGL WILL DRIFT
OVER THE REGION LATER MONDAY MORNING AND MON AFTERNOON.
CLOUD BASES WILL LOWER MONDAY NIGHT (ESP ACROSS THE NORTHERN
AND WESTERN MOUNTAINS OF PA) WITH SOME PERIODS OF LIGHT
SNOW/SNOW SHOWERS DEVELOPING.
OUTLOOK...
MON...NO SIG WX.
TUE...LIGHT SNOW ENTERS W PA MONDAY EVENING AND OVERSPREADS THE
REST OF THE AREA OVERNIGHT MONDAY NIGHT/EARLY TUESDAY. MVFR CIGS
AND VSBYS FOCUSED OVER KJST AND KBFD.
WED...NO SIG WX.
WED NIGHT...PATCHY LIGHT FREEZING RAIN POSSIBLE.
THU...LIGHT RAIN POSSIBLE SOUTH.
FRI...NO SIG WX.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT/FITZGERALD
NEAR TERM...LAMBERT/BANGHOFF
SHORT TERM...LAMBERT/FITZGERALD/BANGHOFF
LONG TERM...BANGHOFF/COLBERT
AVIATION...LAMBERT/GARTNER
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