878
FXUS61 KCTP 231818
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
118 PM EST THU JAN 23 2025
SYNOPSIS
*SLOW CLIMB OUT OF THE DEEP FREEZE THROUGH THE WEEKEND WITH
TEMPERATURES TRENDING CLOSER TO AVERAGE FOR LATE JANUARY
*SNOW SHOWERS TONIGHT INTO FRIDAY WITH MINOR/LIGHT ACCUMULATION
ACROSS THE NORTHWEST MOUNTAINS AND LAUREL HIGHLANDS
*ADDITIONAL PERIODS OF SNOW SHOWERS LIKELY SUNDAY AND EARLY
NEXT WEEK OVER THE ALLEGHENY PLATEAU
NEAR TERM /THROUGH TONIGHT/
ABUNDANT SUNSHINE ACROSS CENTRAL PA AT MIDDAY WITH TEMPS IN THE
20S. 18Z VISIBLE SAT LOOP SHOWS CLOUDS APPROACHING THE WESTERN
ALLEGHENIES WITH VERY LIGHT SNOW/FLURRIES (VIS >=6-7SM) ALONG
THE PA/OH BORDER. HOURLY POPS WILL TREND STEADILY HIGHER OVER
THE WESTERN PART OF THE FORECAST AREA THROUGH 7PM/00Z.
CYCLONIC FLOW WILL BE AMPLIFIED BY A SHORTWAVE MOVING THROUGH
THE FLOW WHICH WILL PUSH A COLD FRONT EASTWARD ACROSS THE GREAT
LAKES AND OHIO VALLEY TODAY AND THROUGH PA TONIGHT (00-12Z FRI).
RENEWED CAA AND NWLY UPSLOPE FLOW WILL DRIVE MINOR/LIGHT
ACCUMULATION ACROSS THE NW MTNS AND LAUREL HIGHLANDS INTO
FRIDAY. WE INCREASED POP/QPF/SNOW FOR LATE TONIGHT WITH HIGH
CONFIDENCE IN LIGHT SNOW ACCUMULATION GIVEN THE FAVORABLE
SYNOPTIC PATTERN AND LIFT WITHIN THE DGZ. EXPECT PARTLY TO
MOSTLY CLOUDY SKIES DOWNWIND OF THE ALLEGHENY FRONT WITH SOME
FLURRIES OR BRIEF SNOW SHOWERS POSSIBLY REACHING THE I99
CORRIDOR LATER TONIGHT INTO AM FRIDAY.
AFTER ANOTHER (BUT THE LAST) VERY COLD START TODAY WITH MIN
TEMPS IN THE NEGATIVE AND POSITIVE SINGLE DIGITS, TEMPS WILL
SLOWLY CLIMB OUT THE RECENT ARCTIC PLUNGE/DEEP FREEZE WITH
AFTERNOON MAXES 10 TO 15 DEGREES HIGHER VS. YESTERDAY (20-30F
RANGE) BUT STILL 5 TO 10 DEGREES BELOW THE HISTORICAL AVERAGE
FOR LATE JANUARY. A SOUTHWEST WIND WILL GUST UP TO 20-25 MPH
ACROSS THE WESTERN ELEVATIONS AS P-GRADIENT TIGHTENS AHEAD OF
THE APPROACHING COLD FRONT WITH WIND CHILLS KNOCKING 10F OFF OF
AFTERNOON HIGHS - MAKING IT FEEL LIKE THE LOW TEENS TO AROUND
20F ACROSS CENTRAL PA.
SHORT TERM /FRIDAY THROUGH SUNDAY/
SNOW SHOWERS CONTINUE INTO FRIDAY FOCUSING MORE OVER THE NW
MTNS. LOW INVERSION HEIGHTS AND A MAINLY FROZEN LK ERIE WILL
CONTINUE TO LIMIT ACCUMULATION TO SOME EXTENT WITH 1-3" FCST
NEAR AND TO THE WEST OF US-219 BY FRIDAY NIGHT (HIGHEST AMOUNTS
IN NORTHWEST WARREN COUNTY AND LAUREL RIDGETOPS/SUMMITS. SNOW
SHOWERS SHOULD END FRIDAY NIGHT, AS SURFACE RIDGING BUILDS INTO
THE STATE AND BOUNDARY LAYER FLOW SHIFTS/BACKS TO THE SOUTHWEST.
NO PRECIP EXPECTED TO START THE LAST WEEKEND OF JANUARY AS SFC
RIDGE AXIS MIGRATES EAST-SOUTHEAST TO THE MID ATLANTIC COAST.
WAA AHEAD OF THE NEXT NORTHERN STREAM SYSTEM SHOULD BRING AN
INCREASE IN CLOUD COVER BY SATURDAY NIGHT. SOME LIGHT SNOW IS
EVEN POSSIBLE AHEAD OF THE NEXT FRONT OVER THE NORTHWEST
ALLEGHENIES BY 00Z SUNDAY. ANOTHER MOISTURE STARVED COLD FRONT
IS FCST TO TRAVERSE CPA SATURDAY NIGHT->EARLY SUNDAY WITH
ENSUING CAA EXPECTED TO DRIVE ANOTHER PERIOD OF LAKE EFFECT
UPSLOPE SNOW SHOWERS OVER THE WESTERN AND NORTHERN MTNS (MINOR
TO LIGHT ACCUMS).
REINFORCING SHOT OF COLD AIR WILL RESULT IN A NEUTRAL TO
NEGATIVE RATE OF CHANGE IN MAX TEMPS ON FRIDAY WITH HIGHS 10 TO
20 DEGREES BELOW CLIMO. A GRADUAL MODERATION (THAWING?) IS THEN
PROJECTED THROUGH THE WEEKEND.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
MEDIUM RANGE GUIDANCE SUPPORTS MAINLY DRY AND SEASONABLY COLD
WEATHER THIS WEEKEND INTO EARLY NEXT WEEK, AS UPPER LEVEL
TROUGHING REMAINS OVER THE REGION DESPITE THE DEPARTURE OF THE
ANOMALOUS COLD. THE 18Z EPS INDICATES A SERIES OF WEAK,
MOISTURE-STARVED SHORTWAVES WILL TRAVERSE THE REGION IN THE
NORTHWEST FLOW. THE PASSAGE OF EACH OF THESE SYSTEMS WILL BRING
THE CHANCE OF A BIT OF VERY LIGHT SNOW OVER THE NW MTNS,
FOLLOWED BY SCATTERED LAKE-ENHANCED OROGRAPHIC SNOW SHOWERS OVER
THE ALLEGHENIES. HOWEVER, A LARGELY FROZEN LK ERIE SHOULD
RESULT IN MINIMAL ACCUMULATIONS.
A FEW ENSEMBLE MEMBERS ARE A BIT DEEPER WITH A PAIR OF
SHORTWAVES EARLY NEXT WEEK, RESULTING IN A WAVE OF LOW PRESSURE
PASSING SOUTH OF PA. THIS SCENARIO WOULD RESULT IN A PERIOD OF
SNOW OVER PRIMARILY SOUTHERN PA. HOWEVER, THIS APPEARS A LOW
PROBABILITY, WITH THE BULK OF GUIDANCE CURRENTLY SUPPORTING DRY
WEATHER OUTSIDE OF SOME VERY LIGHT LAKE-ENHANCED OROGRAPHIC SNOW
OVER THE N AND W MTNS.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE BULK OF THE
DAY TODAY AT ALL TAF SITES, AND WILL CONTINUE TONIGHT AND FRIDAY
THROUGHOUT THE CENTRAL RIDGE AND VALLEY REGION OF THE STATE AND
AT AIRFIELDS IN THE SUSQUEHANNA VALLEY.
THE ARRIVAL OF A COLD FRONT TONIGHT WILL BE ACCOMPANIED AND
FOLLOWED BY A WIND SHIFT TO THE WEST-SOUTHWEST THEN WESTERLY
WITH LIMITED AND RELATIVELY SHALLOW MOISTURE, WHICH WILL SUPPORT
THE DEVELOPMENT OF MVFR CIGS AND PERIODS OF MVFR VSBYS WITH
JUST SOME OCCASIONAL LIGHT SNOW AND FLURRIES ACROSS THE NW MTNS
AND LAUREL HIGHLANDS (KBFD AND KJST).
SIMILAR CONDITIONS WILL PERSIST TONIGHT THROUGH FRIDAY.
OUTLOOK...
THU NIGHT...RESTRICTIONS POSSIBLE AT BFD AND JST WITH -SHSN.
FRI...MVFR/IFR CONDITIONS POSSIBLE WITH -SHSN IN NORTHERN &
WESTERN PA MAINLY DURING THE DAY.
SAT...VFR/NO SIG WX.
SUN-MON...MVFR IN -SHSN POSSIBLE IN NORTHERN & WESTERN PA.
CLIMATE
A RECORD LOW TEMPERATURE OF -11 DEGREES WAS SET AT ALTOONA, PA
EARLY WEDNESDAY MORNING. THE OLD RECORD WAS -5 DEGREES SET IN
1984.
A RECORD LOW TEMPERATURE OF -11 DEGREES WAS ALSO SET AT
JOHNSTOWN, PA EARLY WEDNESDAY MORNING. THE OLD RECORD WAS -9
DEGREES SET IN 1984.
A RECORD LOW TEMPERATURE OF -18 DEGREES WAS TIED AT BRADFORD,
PA EARLY WEDNESDAY MORNING. THE PREVIOUS RECORD LOW TEMPERATURE
DATE WAS 2022.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...LAMBERT/FITZGERALD
AVIATION...LAMBERT/GARTNER
CLIMATE...STEINBUGL
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