227
FXUS61 KCTP 291851
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
251 PM EDT WED APR 29 2026
WHAT HAS CHANGED
* ADDED DETAILS ABOUT THIS AFTERNOON'S SEVERE THREAT.
* EXPANDED DISCUSSION ABOUT FROST/FREEZE POTENTIAL THROUGH THE
WEEKEND.
KEY MESSAGES
1) WET WEDNESDAY WITH WIDESPREAD DRENCHING RAINFALL AND A FEW STRONG
THUNDERSTORMS POSSIBLE IN SOUTHWEST PA
2) CHILLY PATTERN FOR THE END OF APRIL WITH FROST/FREEZE RISK
THROUGH THE FIRST WEEKEND OF MAY
DISCUSSION
KEY MESSAGE 1: WET WEDNESDAY WITH WIDESPREAD DRENCHING RAINFALL AND
A FEW STRONG THUNDERSTORMS POSSIBLE IN SOUTHWEST PA
EXTENSIVE LOW CLOUDS AND RIDGE-SHROUDING/LOCALLY DENSE FOG ACROSS
CPA THIS MORNING. WE ADDED +FG AT ELEVATIONS AOA 2000FT BASED ON
BLEND OF ASOS/RWIS DATA WITH VISIBILITY 0.5-1KFT.
DRENCHING RAINFALL IS EXPECTED TO EXPAND FROM SOUTHWEST TO NORTHEAST
THROUGH THE AFTERNOON AND EVENING BEFORE TAPERING OFF AND SHIFTING
TO THE EAST LATE TONIGHT INTO EARLY THURSDAY MORNING. RAIN MAY BE
HEAVY AT TIMES PARTICULARLY ACROSS THE NW ALLEGHENIES WITH >1"
AMOUNTS POSSIBLE BASED ON HREF/REFS PMM QPF SIGNAL. WHILE LARGELY
BENEFICIAL ESPECIALLY IN D1-D2 DROUGHT AREAS IN THE FAR SOUTHEAST
PART OF THE CWA, SOME ROADWAY PONDING OR MINOR LOW LYING/POOR
DRAINAGE RUNOFF ISSUES ARE POSSIBLE.
SPC HAS MAINTAINED A LEVEL 1/5 MRGL RISK SWO ACROSS THE LAURELS,
WHERE SBCAPE VALUES ARE BETWEEN 500-1000 J/KG & 0-6 KM SHEAR IS
AROUND 40-50 KTS, WITH MINIMAL INSTABILITY EAST OF THE LAURELS
PRECLUDING ANY SEVERE THREAT AT THIS TIME. A MESSY STORM MODE IS IN
PLACE, WITH NEARLY SATURATED PROFILES UP TO 500 MB + UPPER-LEVEL
DIVERGENCE OVER THE LEFT EXIT REGION OF A JET STREAK RESULTING IN A
MIX OF CELLS, CLUSTERS, AND LOOSELY-ORGANIZED LINEAR STORM SEGMENTS.
GIVEN THE MOISTURE IN PLACE, THE THREAT FOR SEVERE WINDS (>=58 KTS)
MAY BE LIMITED DUE TO RELATIVELY WARM COLD-POOL TEMPERATURES, THOUGH
STRONGER CELLS & ORGANIZED LINE SEGMENTS MAY BRING STRONG TO LOCALLY
SEVERE WIND GUSTS. A MARGINAL THREAT OF TORNADOES IS ALSO IN PLACE,
WITH DECENT 0-1KM SRH (100-200 M2/S2) + MEAGER CAPE HINTING AT THE
POTENTIAL FOR LOW-TOPPED SUPERCELLS, THOUGH THREAT FOR TORNADOES
REMAINS LOW GIVEN THE ENVIRONMENT.
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KEY MESSAGE 2: CHILLY PATTERN FOR THE END OF APRIL WITH FROST/FREEZE
RISK THROUGH THE FIRST WEEKEND OF MAY
SEVERAL DISTURBANCES ROTATING AROUND A PERSISTENT UPPER LEVEL CLOSED
LOW CENTERED OVER ONTARIO AND QUEBEC WILL HELP TO REINFORCE BROADLY
DEEP TROUGHING ACROSS THE EASTERN U.S. INTO NEXT WEEK. THIS PATTERN
WILL KEEP CONDITIONS COOL AND UNSETTLED WITH TEMPERATURES BELOW
SEASONAL NORMS. CHILLY NIGHTTIME LOWS WILL ALSO LEAD TO FROST AND
FREEZE CONCERNS THURSDAY-SATURDAY NIGHT, PARTICULARLY NOW THAT THE
GROWING SEASON IS NOW ACTIVE ACROSS ALL CPA ZONES. PATCHY FROST MAY
ALSO DEVELOP ACROSS OUR FAR-NORTHERN COUNTIES TONIGHT, BUT HIGHER
UNCERTAINTY EXISTS GIVEN MILDER TEMPERATURES AND MOSTLY CLOUDY
SKIES. FOR THURSDAY & FRIDAY NIGHTS, FROST/FREEZE CHANCES ARE
PRIMARILY NORTH AND WEST OF I-80/I-99, WITH LIMITING FACTORS BEING
850 MB TEMPERATURES A COUPLE DEGREES WARMER ON THOSE DAYS + CLOUD
COVER FRIDAY NIGHT LIMITING RADIATIONAL COOLING. FROST/FREEZE
POTENTIAL IS HIGHEST SATURDAY NIGHT, WITH HIGH PRESSURE NOSING IN
FROM THE TENNESSEE VALLEY HELPING SKIES TO CLEAR AND WINDS TO
LIGHTEN, WITH THE GREATEST POTENTIAL FOR FROST/FREEZE NORTH AND WEST
OF I-78/I-81.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
AS OF 18Z, WIDESPREAD RAIN IS OVERSPREADING THE REGION, LEADING
TO IFR CONDITIONS TAKING SHAPE IN THE AFTERNOON AND INTO THE
EVENING. CLOUD CEILINGS WILL TAKE SOME MORE TIME TO LOWER IN
MDT & LNS; THEY WILL LIKELY REMAIN MVFR FOR LONGER BEFORE A
TRANSITION TO IFR.
THE COMBINATION OF PRECIPITATION LOWERING VISIBILITIES AND
CLOUD CEILINGS DURING THE EVENING AND OVERNIGHT LEADS TO
CONFIDENCE IN LIFR DEVELOPMENT DURING THIS TAF PERIOD IN BFD,
JST, AOO, AND UNV. CEILINGS AND VISIBILITIES LOOK TO IMPROVE
THROUGHOUT THE MORNING AS DRIER CONDITIONS SET IN.
A LOW PRESSURE SYSTEM AND COLD FRONT WILL TRAVEL WEST TO EAST
THROUGH THE FORECAST PERIOD, LEADING A WIND SHIFT SWEEPING
ACROSS PA. THE SOUTHERLY FLOW REGIME WILL BE REPLACE BY ONE OUT
OF THE NORTHWEST. BFD WILL SEE THE WIND SHIFT FIRST IN THE
EVENING AND IT CROSSES MDT & LNS IN THE LATE NIGHT/EARLY
MORNING. WINDS ARE EXPECTED TO BE LIGHT REGION WIDE WITH SOME
GUSTINESS POSSIBLE LATE IN THE TAF PERIOD FOR MDT & LNS.
OUTLOOK...
THU... DRIER CONDITIONS SET IN, MAINLY MVFR & VFR WITH BFD
POSSIBLY HAVING SOME IFR LINGER INTO THE AFTERNOON. VFR WILL BE
FAVORED IN THE AFTERNOON WITH MANY AREAS SEEING DECREASING CLOUD
COVER.
FRI-SAT...MAINLY VFR WITH BRIEF RESTRICTIONS POSSIBLE IN
SHOWERS.
SUN...RESTRICTIONS POSSIBLE NORTHWEST IN -RA AND POSSIBLY SOME
-SN.
MON... MODELS HINTING AT ANOTHER LOW PRESSURE WAVE TO OUR WEST,
PRECIP MAY LEAD TO RESTRICTIONS, PARTICULARLY IN THE WEST.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...BANGHOFF/TEARE/LAMBRECH
KEY MESSAGES...STEINBUGL/TEARE
DISCUSSION...STEINBUGL/TEARE
AVIATION...LAMBRECH
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