095
FXUS61 KCTP 230213
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
913 PM EST SUN DEC 22 2024
SYNOPSIS
HIGH PRESSURE OVER ONTARIO CANADA JUST TO THE EAST OF GEORGIAN
BAY WILL DRIFT TO THE 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 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, INDICATED THAT
TEMPERATURES ARE ALREADY TRENDING BELOW THE 5TH PERCENTILE NBM
ACROSS PARTS OF THEIR AREA.
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 INTO AT LEAST THURSDAY.
UNCERTAINTY GROWS LATER IN THE WEEK, 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 BY
ANY MEANS OFF THE TABLE.
AVIATION /02Z 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...JUREWICZ/COLBERT
AVIATION...LAMBERT/GARTNER
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