506
FXUS61 KCTP 231900
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
200 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 WEDNESDAY/
THE BULK OF CENTRAL PENNSYLVANIA IS EXPECTED TO EXPERIENCE DRY
AND COOLER THAN AVERAGE TEMPERATURES; HOWEVER, TEMPERATURES ARE
EXPECTED TO WARMER COMPARED TO THE RECENT COLD SNAP OBSERVED
ACROSS THE REGION. MODEL GUIDANCE CONTINUES TO INDICATE A
MULTITUDE OF SHORTWAVES APPROACHING THE REGION THROUGHOUT THE
LONG-TERM PERIOD; HOWEVER, GUIDANCE DOES CONTINUE TO INDICATE
THAT MOISTURE WITH THESE SHORTWAVES WILL BE LACKING, WITH
RECENT GFS MODEL GUIDANCE OUTLINING NEGATIVE PWAT ANOMALIES
THROUGHOUT MUCH OF THE WEEK. FORCING WILL REMAIN FAVORABLE WITH
THESE SHORTWAVE, COUPLED WITH WESTERLY WINDS, SO HAVE CONTINUED
MENTIONS OF SNOW SHOWERS ACROSS THE FAVORED AREAS OF NW PA AND
THE LAUREL HIGHLANDS, WITH MINIMAL ACCUMULATIONS EXPECTED.
THE PASSAGE OF AN ARCTIC FRONT LATE TUESDAY AND INTO WEDNESDAY,
COUPLED WITH A SLIGHT SURGE IN MOISTURE, HAS THE POTENTIAL TO
BRING ABOUT A FAVORABLE SETUP FOR SNOW SQUALLS; HOWEVER,
CONFIDENCE REMAINS LOW IN THIS SOLUTION GIVEN SOME MODEL TIMING
DIFFERENCES AND UNCERTAINTY WITH REGARDS TO HOW MUCH
INSTABILITY WILL BE PRESENT AS IT SEEMS MORE PLAUSIBLE THAT THE
FRONTAL MOVES IN WELL AFTER SUNSET ON TUESDAY. GIVEN THAT RECENT
ANALOGS HAVE ALSO OUTLINED THIS POTENTIAL ACROSS THE NORTHERN
TIER OF PENNSYLVANIA AND GIVEN THE SYNOPTIC SETUP LEADING UP TO
THIS POTENTIAL, THIS POTENTIAL IS WORTHY OF MENTIONING IN THE
AFD WHILE ALSO OUTLINING THE UNCERTAINTY IN THIS SOLUTION. THE
THREAT IS EXPECTED TO END PRIOR TO SUNRISE ON WEDNESDAY, WHERE
DRIER AIR BEHIND THE FRONT WILL LEAD TO DRY AND RELATIVELY
COLDER CONDITIONS COMPARED TO THE WEEKEND/EARLY WEEK, OUTSIDE OF
NW PA/THE LAURELS WHERE UPSLOPE AND LAKE EFFECT SNOW SHOWERS
REMAIN POSSIBLE.
AVIATION /19Z THURSDAY THROUGH TUESDAY/
THE BULK OF MODEL GUIDANCE IS IN AGREEMENT THAT VFR CONDITIONS
WILL PREVAIL AT ALL AIRFIELDS OUTSIDE OF BFD/JST WITH HIGH
CONFIDENCE (~80-90%) THROUGH 18Z FRIDAY, WITH THE MAIN CONCERN
AT AOO/UNV/IPT/MDT/LNS BEING BREEZY SUSTAINED WINDS NEAR 5-10KTS
AT 250-300, WITH GUSTS UP TO 20KTS AFTER 12Z FRIDAY.
AT BFD/JST, LAKE EFFECT AND OROGRAPHICALLY ENHANCED SNOW
SHOWERS WILL BRING ABOUT MVFR VISIBILITIES WITH BORDERLINE
IFR/MVFR CEILINGS, MAINLY SITUATED LATER THIS EVENING (22Z TO
04Z FRIDAY) AND AFTER SUNRISE ON FRIDAY (12Z TO 18Z FRIDAY). A
COMBINATION OF HREF/RAP MODEL GUIDANCE DOES SUGGEST THE
POTENTIAL FOR PERIOD WHERE SNOW SHOWERS DO NOT IMPACT THESE
AIRFIELDS; HOWEVER, GIVEN SOME RESIDUAL MOISTURE, HAVE LEFT
MENTIONS OF VCSH IN THE TAFS THROUGHOUT THIS TIMEFRAME WITH
MODERATE (40-50%) CONFIDENCE. ANY ALTERNATIVE SOLUTION AT
BFD/JST WILL MAINLY ENTAIL LESS SNOW COVERAGE, WHICH COULD ALLOW
FOR A LONGER DURATION OF MVFR CONDITIONS WITH IFR CONDITIONS
LESS LIKELY; HOWEVER, THIS IS A LOWER CONFIDENCE (~30%) SOLUTION
AT THIS TIME.
OUTLOOK...
SAT...VFR/NO SIG WX.
SUN-TUE...MVFR POSSIBLE IN -SHSN ACROSS 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...NPB
AVIATION...NPB
CLIMATE...STEINBUGL
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