238
FXUS61 KCTP 200927
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
427 AM 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 /UNTIL 6 AM THIS MORNING/
REGIONAL RADAR AT 09Z SHOWS LIGHT SNOW SPREADING INTO WESTERN PA
IN REGION OF STRONG LARGE SCALE FORCING/UPPER LEVEL DIFFLUENCE
AHEAD OF A CLOSED UPPER LOW OVER OHIO. RADAR AND SURFACE OBS
INDICATES SOME VERY LIGHT SNOW MAY HAVE ALREADY ENTERED WARREN
COUNTY AND SHOULD REACH MOST OF THE ALLEGHENY PLATEAU BY DAWN.
UPSTREAM VSBYS ARE MAINLY IN THE 2-4SM RANGE, SO ANY
ACCUMULATIONS FOR THE MORNING COMMUTE SHOULD BE VERY LIMITED
(<0.5 INCH).
AHEAD OF THE UPPER LOW, LAKE EFFECT STRATOCU IS HOLDING TEMPS
IN CHECK ACROSS THE N MTNS, WHILE CLEAR SKIES AND LIGHT WIND HAS
RESULTED IN EFFICIENT RADIATIONAL COOLING WITH TEMPS FALLING
BELOW NBM GUIDANCE OVER THE SOUTHERN HALF OF THE FORECAST AREA.
MANY LOCATIONS ACROSS THE LAURELS AND SC MTNS HAVE DIPPED INTO
THE SINGLE DIGITS EARLY THIS MORNING. HOWEVER, ARRIVING CLOUDS
WILL LIKELY RESULT IN READINGS LEVELING OFF OR RISING TOWARD
DAWN OVER MUCH OF CENTRAL PA.
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/
THE DEEPENING UPPER LOW 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 MAXTEMPS, 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.
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 WEDNESDAY/
LATE EVENING UPDATE.
NOT A LOT OF CHANGE TO THIS SECTION. AS NOTED BELOW, HIGH
PRESSURE WILL RESULT IN A DRY WEEKEND, WITH MODERATING
TEMPERATURES.
SEVERAL WEAK SYSTEMS WILL BRING SOME PRECIPITATION TO THE
AREA NEXT WEEK, BUT NO REAL EXTREME EVENTS, THAT WE HAVE
SEEN LATELY.
EARLIER DISCUSSION BELOW.
HIGH PRESSURE AT THE SURFACE WILL PROVIDE DRY WEATHER THROUGH
THE WEEKEND. A COUPLE OF SHORTWAVES PASSING THROUGH WILL LEAD TO
NOTHING MORE THAN INCREASED CLOUD COVER, ESPECIALLY ACROSS THE
NORTHERN AND WESTERN MOUNTAINS. THE MOST NOTICEABLE THING THIS
WEEKEND WILL BE THE WARMER TEMPERATURES. HIGH TEMPS BY SUNDAY
WILL BE IN THE 40S IN THE LOWER SUSQUEHANNA VALLEY, WHILE THE
INCREASED CLOUD COVER OVER THE NORTH AND WEST WILL KEEP
TEMPERATURES IN THE 30S.
BY MONDAY NIGHT INTO TUESDAY, ANOTHER MORE POTENT SHORTWAVE IS
PROGGED TO DRIFT ACROSS PENNSYLVANIA AS LOW PRESSURE PASSES
NORTH OF THE STATE. THERE IS STILL SOME DIFFERENCES IN THE
MODELS AS TO HOW THIS SYSTEM EVOLVES, BUT RAIN WITH SOME SNOW
MIXED IN FOR HIGHER ELEVATIONS APPEARS MOST LIKELY AT THIS
POINT. UPSLOPE AND LAKE EFFECT PRECIPITATION WILL LINGER ACROSS
THE WESTERN HALF OF CENTRAL PA INTO WEDNESDAY. MOST GUIDANCE
INDICATES THE POTENTIAL FOR ANOTHER SYSTEM TO IMPACT THE REGION
IN THE THURSDAY/FRIDAY TIMEFRAME, BUT THERE IS TOO MUCH
UNCERTAINTY TO GET INTO ANY SPECIFICS YET.
AVIATION /09Z THURSDAY THROUGH MONDAY/
VFR CONDITIONS WITH THIN LAYERED MID AND HIGH CLOUDS CONTINUE
EVERYWHERE THIS EVENING, EXCEPT BFD WHERE MVFR CEILINGS WILL
PERSIST THROUGH THE TAF PERIOD. LIGHT NORTHWEST WINDS WILL ALSO
CONTINUE THROUGH THE OVERNIGHT.
A DEEP UPPER LEVEL LOW TRACKING ACROSS PA THURSDAY WILL BRING
WIDESPREAD SNOW SHOWERS TO THE REGION. CEILINGS WILL LOWER TO
MVFR OUTSIDE OF MDT AND LNS AS THE SNOW BEGINS TO FALL. IFR
VISIBILITY IS EXPECTED AT BFD, JST, AND AOO AS WELL. WIND GUSTS
BEGIN TO INCREASE THURSDAY AFTERNOON AFTER 18Z, WITH GUST OF 25
TO 35 KNOTS POSSIBLE.
OUTLOOK...
FRI...MVFR/IFR AT KBFD & KJST (MVFR TO LOW VFR ELSEWHERE). SNOW
SHOWERS AND GUSTY WINDS DIMINISHING BY FRIDAY NIGHT.
SAT-SUN...VFR/NO SIG WX.
MON...RAIN AND SNOW SHOWERS DEVELOPING IN THE AFTERNOON.
CTP WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR PAZ033.
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...BANGHOFF/MARTIN/BAUCO
AVIATION...BAUCO/RXR
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