316
FXUS61 KCTP 211234
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
734 AM EST FRI FEB 21 2025
SYNOPSIS
* GUSTY NORTHWEST WINDS CONTINUE TODAY AS UPSLOPE SNOW SHOWERS
GRADUALLY TAPER OFF.
* DRY CONDITIONS PREVAIL THIS WEEKEND WITH HIGH PRESSURE
BUILDING IN AND TEMPERATURES TRENDING UP.
* A COUPLE SYSTEMS WILL BRING RAIN - AND PERHAPS SOME SNOW -
DURING THE LAST WEEK IN FEBRUARY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
A COLD NORTHWEST FLOW ORIGINATING OVER LK HURON CONTINUES TO
PRODUCE LIGHT, LAKE-ENHANCED SNOW/FLURRIES OVER THE ALLEGHENIES
EARLY THIS MORNING. MODEL QPF SUPPORT UP TO AN HALF INCH OF
ADDITIONAL ACCUMULATION ON LAUREL RIDGE EARLY THIS MORNING, WITH
NO MORE THAN A DUSTING ELSEWHERE. FALLING INVERSION HEIGHTS
UPON THE APPROACH OF HIGH PRESSURE WILL CAUSE ANY LINGERING
LIGHT SNOW SHOWERS/FLURRIES OVER THE NW MTNS AND LAURELS TO
TAPER OFF THIS AFTERNOON, WITH NO ADDITIONAL ACCUMULATION
EXPECTED.
A TIGHT GRADIENT BETWEEN EXPANSIVE HIGH PRESSURE IN THE MISS
VALLEY AND AN INTENSE LOW SOUTHEAST OF NEWFOUNDLAND WILL
CONTINUE TO PRODUCE FAIRLY GUSTY NORTHWEST WINDS TODAY. BUFKIT
SOUNDINGS SUPPORT GUSTS A BIT ABOVE NBM GUIDANCE WITH FREQUENT
GUSTS AROUND 25KTS TODAY.
MODEL RH PROFILES INDICATE LAKE EFFECT STRATOCU WILL BE
PERSISTENT TODAY ACROSS THE ALLEGHENIES, WHILE SUBSIDENCE TO
THE LEE OF THE MOUNTAINS SHOULD RESULT IN PARTLY TO MOSTLY SUNNY
SKIES IN THE SUSQ VALLEY. MODERATING TEMPS ARE EXPECTED TODAY
WITH THE DEPARTURE OF THE UPPER LOW. MIXING DOWN 900MB TEMPS OF
-10C TO -13C YIELDS EXPECTED HIGHS RANGING FROM AROUND 20F OVER THE
N MTNS, TO THE LOW 30S IN THE LOWER SUSQ VALLEY.
SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/
SURFACE HIGH PRESSURE OVER THE OHIO VALLEY WILL NOSE INTO PA
TONIGHT, PROVIDING THE REGION WITH FAIR/COLD CONDITIONS AND
RELATIVELY LIGHT WINDS. MODEL SOUNDINGS CONTINUE TO INDICATE LOW
LEVEL MOISTURE TRAPPED BENEATH A STRONG SUBSIDENCE INVERSION
WILL RESULT IN LINGERING LOW CLOUDS OVER THE ALLEGHENIES
TONIGHT, WHILE MAINLY CLEAR SKIES ARE ANTICIPATED TO THE LEE
(EAST) OF THE MOUNTAINS.
HIGH PRESSURE IS PROGGED TO PASS SOUTH OF PA THIS WEEKEND, RESULTING
IN FAIR WEATHER, WITH A WEST-SOUTHWEST FLOW IMPORTING MILDER
AIR INTO PA. A PAIR OF MOISTURE-STARVED SHORTWAVES SHOULD
TRAVERSE THE REGION, ONE SAT PM AND ANOTHER SUN PM. ALTHOUGH NO
PRECIPITATION IS EXPECTED FROM THESE SYSTEMS, COLD TEMPS ALOFT
SHOULD RESULT IN A DECENT AMOUNT OF AFTERNOON CUMULUS OVER THE
NORTHERN TIER OF THE STATE, ESPECIALLY SUNDAY.
GEFS 2M TEMP ANOMALIES SUGGEST READINGS THIS WEEKEND WILL GET
BACK TO NEAR NORMAL BY SUNDAY, WITH HIGHS RANGING FROM THE LOW
30S OVER THE N MTNS, TO THE MID 40S IN THE LOWER SUSQ VALLEY.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
LATE EVENING UPDATE.
NOT A LOT OF CHANGE TO THE EXTENDED PART OF THE FORECAST.
RAN FORECAST BUILDER, SOME MINOR CHANGES TO THE EARLIER
GRIDS. MAIN THING WAS A BIT WETTER LATER ON MONDAY AND COOLER
LATER NEXT WEEK.
WHILE WE GET A BREAK FROM THE COLD WEATHER THIS WEEKEND INTO
THE FIRST PART OF NEXT WEEK, THE LARGE SCALE WEATHER PATTERN
REMAINS SIMILAR TO MUCH OF THE WINTER SO FAR. A LARGE SCALE
TROUGH IS LIKELY TO BE IN PLACE ACROSS THE EAST BY EARLY
MARCH, WHICH WOULD SUPPORT BELOW NORMAL TEMPERATURES AGAIN.
ANYWAY, EARLIER INFORMATION BELOW.
KEY TAKEAWAYS: MONDAY, FEBRUARY 24 - THURSDAY, FEBRUARY 27
------------------------------------------------------------
*WARMING TREND TO NEAR/ABOVE HISTORICAL AVERAGES TO END FEBRUARY
*QUICK MOVING SYSTEMS BRING PASSING RAIN/SNOW SHOWERS MON-TUE
*HIGHEST PROBABILITY & CONFIDENCE IN WIDESPREAD PRECIP THU-FRI
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 /13Z FRIDAY THROUGH TUESDAY/
12Z UPDATE: LITTLE CHANGE FROM THE EARLIER DISCUSSION, OTHER
THAN SLIGHTLY LOWERING VSBYS ACROSS THE CENTRAL AND WESTERN TAF
SITES AND EXTENDING THESE CONDITIONS THROUGH 15Z WITH TEMPOS FOR
IMPROVED MVFR/VFR CONDITIONS. THE MESOSCALE VOR CENTER MENTIONED
BELOW IS ON TRACK TO SLIDE ACROSS THE LAUREL HIGHLANDS WITHIN
THE NEXT FEW HOURS, ACCOMPANIED BY IFR TO BRIEF LIFR VSBYS AT
KJST AND GENERALLY MVFR CIGS AND BRIEF MVFR VSBYS AT KAOO AND
KUNV. ELSEWHERE, KBFD WILL BE SIMILAR TO KJST IN CIGS AND VSBYS
THROUGH LATE THIS MORNING (VARYING BETWEEN 3/4SM AND 1 1/2SM),
BEFORE RISING TO 6SM+. THE SUSQ AIRFIELDS WILL SEE VARYING
AMOUNTS OF STRATOCU IN THE MVFR (035-045) RANGE.
06Z UPDATE: A FAIRLY WELL-ALIGNED NW FLOW WAS SEEN IN THE LOW
TO MID LEVELS EARLY TODAY, WITH ABOUT 30-40 DEGREES OF
DIRECTIONAL SHEAR AND ABOUT +30 KTS OF SPEED SHEAR BETWEEN THE
SURFACE AND 5 KFT AGL. (LEADING TO PLENTY OF TURBULENT MIXING
AND MODERATE SFC GUSTS INTO THE MID AND UPPER 20S WITH SOME PEAK
GUSTS OVER 30 KTS).
MRMS RADAR COMPOSITE LOOP SHOWS A WELL-DEFINED MESOSCALE
VORTICITY MAX AND AREA OF ENHANCED SNOW SHOWERS THAT WILL BE
MOVING ACROSS SWRN PA AND THE LAUREL HIGHLANDS THROUGH 13Z (SE
AT AROUND 32KTS). THIS FEATURE COULD DROP VSBYS DOWN TO AROUND
1SM WITH MVFR CIGS DIPPING INTO THE IFR RANGE AT TIMES. KBFD
COULD SEE A SIMILAR TREND TO OCNLY IFR CIGS AND VSBYS.
THESE 2 WRN MTN TAF SITES WILL LIKELY SEE -SHSN AND VARIABLE
MVFR TO IFR CONDITIONS THROUGH ABOUT 17Z-18Z AS THE ENTIRE ~
3KFT DEPTH OF THE LAKE ENHANCED/UPSLOPE STRATO CU RESIDES WITHIN
THE FAVORABLE DENDRITIC SNOW GROWTH THERMAL ZONE OF -12C TO
-18C.
MUCH THINNER CLOUD COVER WILL EXIST ACROSS THE CENTRAL RIDGE
AND VALLEY REGION AND SUSQ VALLEY WITH MVFR AT KAOO AND KUNV AND
MAINLY VFR CIGS AT KIPT (WITH BRIEF MVFR AT KIPT THIS MORNING)
AND PERSISTENT VFR CONDITIONS AT KMDT AND KLNS.
THE NW WIND WILL BEGIN TO DIMINISH LATE TODAY AS SUNSET
APPROACHES, BUT SOME G20KT LINGER FRI EVENING.
GENERALLY VFR ACROSS THE CENTRAL AND SE TAF SITES TONIGHT INTO
SATURDAY, BUT A WEAKENING BUT STILL RELATIVELY MOIST LLVL
UPSLOPE FLOW WILL LIKELY LEAD TO MVFR TO IFR CIGS AND POSSIBLY
BRIEF LIFR AT KBFD AROUND OR AFTER 05Z SAT.
OUTLOOK...
SAT-SUN...VFR/NO SIG WX.
MON...RAIN AND SNOW SHOWERS DEVELOPING IN THE AFTERNOON NW.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...BANGHOFF
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/BANGHOFF
LONG TERM...STEINBUGL/MARTIN
AVIATION...LAMBERT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page