626
FXUS61 KCTP 201829
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
129 PM EST THU FEB 20 2025
SYNOPSIS
AN UPPER LEVEL LOW WILL TRACK ACROSS PENNSYLVANIA TODAY, THEN A
MORE ZONAL PATTERN WILL DEVELOP OVER THE CONUS THIS WEEKEND. A
WEAK SHORTWAVE AND ASSOCIATED COLD FRONT IS LIKELY TO PUSH
THROUGH THE REGION TUESDAY OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
SNOW HAS BEEN VERY LIGHT ACROSS ALL OF THE AREA. HIDDEN VALLEY
DID HAVE ALMOST AN INCH (0.9") OF SNOWFALL BY THEIR CO-OPERATIVE
OBSERVATION THIS MORNING. JST HAS DIPPED AS LOW AS 1/2SM VISBY
THIS AM. SO, THOSE HILLS ARE PRODUCING WHAT THEY SHOULD. SEE NO
REASONS TO MODIFY THE FORECAST BEYOND TEMP/DEW TWEAKS FOR THE
NEAR TERM. WILL CONTINUE TO MENTION 0.1" ACCUMS ACROSS THE
ENTIRE CWA, AS IT HAS STARTED TO SNOW OVER THE SE AND MAY
CONTINUE THROUGH THE MIDDLE OF THE AFTN. WHILE IT HAS BARELY
STARTED TO MAKE THE TOPS OF THE CARS SLUSHY IN THE PARKING LOT,
WE STILL HAVE A COUPLE MORE HOURS OF LIGHT SNOW TO GO.
PREV...
A DEEPENING UPPER LOW OVER OHIO WILL PASS OVER PA LATER TODAY.
STRONG LARGE SCALE FORCING/UPPER LEVEL DIFFLUENCE AHEAD OF THIS
FEATURE SHOULD SUPPORT A PERIOD OF LIGHT SNOW OVER MOST OF
CENTRAL PA. HOWEVER, A LACK OF MOISTURE WITH THIS SYSTEM SHOULD
KEEP ACCUMULATIONS VERY LIGHT. ENSEMBLE MEAN QPF SUPPORTS SNOW
TOTALS RANGING FROM <1 INCH SOUTHEAST OF THE ALLEGHENY PLATEAU,
TO AS MUCH AS 3-4 INCHES ALONG LAUREL RIDGE IN SOMERSET COUNTY,
WHERE LINGERING LAKE-ENHANCED UPSLOPE SNOW WILL LAST THROUGH
TONIGHT. MODEL TIME/HEIGHT PROFILES INDICATE MUCH OF THE CLOUD
LAYER WILL FALL WITHIN THE DGZ, SUPPORTING SNOW/WATER RATIOS
CLOSE TO 20/1.
AS THE UPPER LOW EXITS THE REGION LATE TODAY, EXPECT THE LIGHT
SNOW TO TAPER OFF OVER MUCH OF CENTRAL PA. HOWEVER, A COLD
NORTHWEST FLOW WILL GENERATE LINGERING LIGHT SNOW SHOWERS OVER
THE ALLEGHENIES THAT WILL LAST THROUGH TONIGHT. A TIGHT
PRESSURE GRADIENT, AIDED BY SUBSIDENCE FORCED BY DIFFERENTIAL
ANTICYCLONIC VORTICITY ADVECTION, WILL RESULT IN GUSTY NORTHWEST
WINDS LATE THIS AFTERNOON INTO TONIGHT. BUFKIT SOUNDINGS SUPPORT
HIGHER WINDS THAN NBM GUIDANCE, WITH GUSTS LATE TODAY AND THIS
EVENING IN THE 25-35KT RANGE, WITH THE HIGHEST GUSTS OVER THE
LAURELS/SC MTNS. THESE WINDS, COMBINED WITH AN INCH OR TWO OF
DRY, FLUFFY SNOW, SHOULD CAUSE SOME BLOWING/DRIFTING OVER THE
LAURELS LATE TODAY/EVENING
MAINLY OVERCAST SKIES AND A POOL OF ANOMALOUSLY COLD AIR ALOFT
WILL RESULT IN MAX TEMPS WELL BELOW SEASONAL NORMALS TODAY. SEE
NO REASON TO DEVIATED FROM TODAY'S NBM MAX TEMPS, WHICH RANGE
FROM THE UPPER TEENS OVER THE ALLEGHENIES, TO THE UPPER 20S OVER
THE LOWER SUSQ VALLEY. THE UPPER LOW AND ASSOCIATED CORE OF
COLDEST AIR ALOFT WILL BE EXITING THE STATE TONIGHT, SO DON'T
ANTICIPATE TEMPS FALLING MUCH OVERNIGHT. READINGS BY DAWN
SHOULD RANGE FROM THE TEENS OVER MOST OF CENTRAL PA.
SHORT TERM /FRIDAY/
FALLING INVERSION HEIGHTS SHOULD CAUSE LINGERING LAKE EFFECT
SNOW SHOWERS/FLURRIES TO TAPER OFF FRIDAY OVER THE NW
MTNS/LAURELS, WITH INCREASING SUNSHINE TO THE LEE OF THE
ALLEGHENIES. GEFS 2M TEMP ANOMALIES INDICATE HIGHS FRIDAY WILL
BE 7-12F BELOW AVERAGE, TRANSLATING TO HIGHS FROM AROUND 20F
OVER THE N MTNS, TO MID 30S IN THE LOWER SUSQ VALLEY. A GUSTY
NORTHWEST WIND WILL ADD TO THE CHILL. MODEL SOUNDING SUPPORT
FREQUENT GUSTS TO AROUND 25KTS.
LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/
SURFACE RIDGE AXIS WILL RIPPLE THROUGH CPA FRIDAY NIGHT AND
SATURDAY. FRIDAY NIGHT WILL MARK A SHORT TERM BOTTOM FOR TEMPS
WITH LOWS IN THE +SINGLE DIGITS AND TEENS. LOW LEVEL MOISTURE
TRAPPED BENEATH A SUBSIDENCE INVERSION MAY YIELD LINGERING LOW
CLOUDS ACROSS THE NW MTNS AND LAUREL HIGHLANDS FRIDAY NIGHT INTO
EARLY SATURDAY. OTHERWISE, MODEL RH PROFILES SUPPORT A PARTLY
TO MOSTLY SUNNY START TO THE LAST WEEKEND OF FEBRUARY WITH MAX
TEMPS CLIMBING +10 DEGREES DAY OVER DAY (VS. FRIDAY) INTO THE
30-40F RANGE.
KEY TAKEAWAYS: SATURDAY, FEBRUARY 22 - THURSDAY, FEBRUARY 27
------------------------------------------------------------
*WARMING TREND TO NEAR/ABOVE HISTORICAL AVERAGES TO END FEBRUARY
*NO PRECIPITATION FOR THE LAST WEEKEND OF FEBRUARY
*QUICK MOVING SYSTEMS BRING PASSING RAIN/SNOW SHOWERS MON-TUE
*HIGHEST PROBABILITY & CONFIDENCE IN WIDESPREAD PRECIP THU-FRI
DRY WEATHER AND MODERATING TEMPERATURES [WARMING TREND] EXPECTED
FOR THE LAST WEEKEND OF FEBRUARY 2025. THERE WILL BE INTERVALS
OF CLOUDS AND SUN WITH MORE SUNSHINE IN THE SOUTH/EASTERN PART
OF THE FORECAST AREA.
A PAIR OF FAST MOVING NORTHERN STREAM SHORTWAVES WILL BRING
PASSING RAIN/SNOW SHOWERS EARLY NEXT WEEK. SNOW SHOWERS ARE
MOST LIKELY OVER THE HIGHER ELEVATIONS WITH RAIN SHOWERS IN THE
VALLEYS. MAX POPS ARE ON TUESDAY BASED ON NBM AND EC/CMC/GFS
LIKELY FOLLOWED BY SOME LINGERING LIGHT PRECIP DOWNWIND OF LAKE
ERIE AND OVER THE WESTERN ALLEGHENIES/LAUREL HIGHLANDS TUE NIGHT
INTO EARLY WEDNESDAY. THE LATEST DETERMINISTIC, ENSEMBLE, AND
MACHINE LEARNING MODELS SHOW A LARGER STORM SYSTEM IMPACTING THE
REGION IN THE THURSDAY/FRIDAY TIMEFRAME WITH THE POTENTIAL FOR
RAIN AND SNOW. WE HAVE ABOVE AVERAGE CONFIDENCE IN MEASURABLE
PRECIP IN THIS TIME WINDOW (STICKING WITH NBM MAX POP 65-80%),
BUT DETAILS CONCERNING WINTER WX/PTYPE/ACCUMULATION ARE STILL
NOT CLEAR AT THIS RANGE. SOME LOCATIONS IN THE LOWER SUSQUEHANNA
VALLEY COULD REACH THE 50F MARK FOR 4 CONSECUTIVE DAYS MON-THU.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
JUST TEMPORARY DIPS BELOW 1SM AT JST AND BFD, BUT GENERALLY 2SM+
VISBYS AT AOO-UNV-IPT. MDT JUST STARTED SNOWING BUT HAS ALREADY
BOUNCED BACK UP (FROM 3SM) INTO VFR VISBY AND A CIG JUST DOWN
INTO MVFR (FL027) AT 16Z. LNS STILL WAITING FOR THEIR FLAKES TO
START. SHOULD BE THERE SOON.
WIND GUSTS HAVE ALREADY BEGUN TO INCREASE AND SHOULD KEEP
GETTING STRONGER WITH GUST OF 25 TO 35 KNOTS POSSIBLE. STEADY
SNOW EXITS BY EARLY EVENING (EARLIER IN MANY PLACES), BUT
ADDITIONAL UPSLOPE AND LAKE ENHANCED SNOW SHOWERS WILL CONTINUE
INTO THE LAUREL HIGHLANDS AND NW MTNS (KJST AND KBFD), WITH MVFR
TO IFR CIGS HOLDING ON THERE INTO AT LEAST FRIDAY MORNING. BFD
WILL BE THE LAST PLACE TO GO VFR ON FRIDAY WITH THE STRATOCU
HANGING ON LONGEST OVER NRN PA. THE WIND WILL BEGIN TO DIMINISH
FRIDAY MID-DAY, BUT SOME G20KT LINGER INTO FRI EVENING.
OUTLOOK...
FRI NIGHT-SUN...VFR/NO SIG WX.
MON...RAIN AND SNOW SHOWERS DEVELOPING IN THE AFTERNOON NW.
CTP WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR PAZ033.
SYNOPSIS...FITZGERALD/DANGELO
NEAR TERM...FITZGERALD/DANGELO
SHORT TERM...FITZGERALD
LONG TERM...STEINBUGL
AVIATION...DEVOIR/DANGELO
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