307
FXUS61 KCTP 030515
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
115 AM EDT SAT MAY 3 2025
SYNOPSIS
* SHOWERS AND THUNDERSTORMS CONTINUE THROUGH SATURDAY. A FEW
STORMS SATURDAY AFTERNOON MAY PRODUCE DAMAGING WIND GUSTS AND
LARGE HAIL OVER THE LOWER SUSQUEHANNA VALLEY.
* LARGELY BENEFICIAL MULTI-DAY RAINFALL EVENT LIKELY SUNDAY
THROUGH TUESDAY; SOME MINOR FLOODING WILL BE POSSIBLE WITH ANY
REPEATED ROUNDS OF HEAVY RAIN
NEAR TERM /UNTIL 7 AM THIS MORNING/
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE EASTERN
HALF OF THE REGION, WHILE MAINLY DRY CONDITIONS WILL CONTINUE
FOR THE NEXT FEW HOURS ACROSS THE WEST. A WAVE OF LOW PRESSURE
APPROACHING FROM THE WEST WILL BRING ANOTHER ROUND OF RAINFALL
TO CENTRAL PA BEFORE SUNRISE. LOW TEMPERATURES TONIGHT WILL
RANGE FROM THE LOW 50S ACROSS THE NORTHERN TIER, TO NEAR 60 FOR
THE SOUTHEAST. MOISTURE FROM TODAY'S RAINFALL ALONG WITH LIGHT
WINDS SHOULD ALLOW FOR SOME PATCHY FOG TO DEVELOP ACROSS THE
NORTH.
SHORT TERM /7 AM THIS MORNING THROUGH MONDAY/
BLOCKING PATTERN SETS UP OVER THE WEEKEND WITH A DEEP/VERTICALLY
STACKED LOW IN THE OH VALLEY. RAIN IS EXPECTED TO EXTEND TO THE
NORTHEAST ALONG A COLD FRONT EXTENDING THROUGH CPA INTO NEW
ENGLAND. CONVECTION IS EXPECTED TO DEVELOP DURING THE AFTERNOON
AHEAD OF THE ADVANCING COLD FRONT WITHIN A MODESTLY DESTABILIZING
AIRMASS. THE MAIN QUESTING REGARDING CONVECTION IS HOW MUCH
INSTABILITY DEVELOPS DURING THE AFTERNOON WITH LOTS OF CLOUD
COVER EXPECTED TO REMAIN IN PLACE. SPC ADDED A SLIGHT RISK
ACROSS THE LOWER SUSQUEHANNA VALLEY WHERE DIFFERENTIAL
HEATING/INSTABILITY AND EFFECTIVE SHEAR VALUES WOULD TEND TO
FAVOR MORE ORGANIZED/STRONGER UPDRAFTS.
THE UPPER LEVEL CLOSED LOW MEANDERS IN THE OHIO VALLEY INTO
EARLY NEXT WEEK. SOUTHERLY FLOW ON THE EAST SIDE OF THE LOW WILL
CHANNEL MOISTURE INTO THE AREA WITH PERIODS OF RAIN EXPECTED
SUNDAY AND MONDAY. WHILE RAINFALL WILL BE CERTAINLY BENEFICIAL
AND BRING SOME RELIEF TO DROUGHT CONDITIONS PARTICULARLY IN THE
SOUTHEAST PART OF THE FORECAST AREA, WE WILL NEED TO MONITOR
CONDITIONS FOR REPEATED ROUNDS OF HEAVY RAINFALL WHICH COULD
PRODUCE LOCALLY HEAVY TOTALS AND MAY RESULT IN LOCALIZED
FLOODING IN URBAN AND POOR DRAINAGE AREAS. WPC HAS MAINTAINED
MARGINAL EXCESSIVE RAIN RISKS FOR SATURDAY-MONDAY.
THIS PERIOD WILL REMAIN MILD RELATIVE VS. CLIMO WITH THE
LARGEST DEPARTURES FROM NORMAL IN THE OVERNIGHT MIN TEMPS
ON THE ORDER OF +10-20F ABOVE THE HISTORICAL AVERAGE.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
BLOCKY PATTERN WITH CLOSED LOW LIFTING VERY SLOWLY TO THE
NORTHEAST FROM THE OHIO VALLEY WILL MAINTAIN A STRONG WET
PATTERN SIGNAL OVER THE AREA THROUGH MIDWEEK. INITIALLY,
RAINFALL SHOULD BE BENEFICIAL PARTICULARLY OVER THE SOUTHEAST
ZONES/LOWER SUSQ WHERE D1/D2 DROUGHT CONDITIONS HAVE PERSISTED
FOR SOME TIME. WPC HAS INDICATED A MARGINAL RISK OF EXCESSIVE
RAIN WITH SOME POTENTIAL FOR REPEATED ROUNDS OF RAIN CAPABLE OF
PRODUCING LOCALIZED FLOODING RISK IN URBAN AND POOR DRAINAGE
AREAS. THE MAIN UNCERTAINTY IN THE FORECAST PERIOD IS IN REGARD
TO HOW QUICKLY THE UPPER LOW BEGINS TO MOVE OFF TO THE EAST.
SOME GUIDANCE SUGGESTS A MAINLY DRY SECOND HALF OF THE WEEK AS
HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING UPPER LOW, WHILE
SOME MODELS KEEP THE LOW AROUND A LITTLE LONGER. BECAUSE OF
THIS UNCERTAINTY, WE HAVE NOT DEVIATED FROM THE NBM THROUGH THE
END OF THE EXTENDED PERIOD.
AVIATION /05Z SATURDAY THROUGH WEDNESDAY/
LOOKING AT CLEAR SKIES WITH SOME FOG ACROSS THE REGION EARLY
ON, THEN THE REMAINS OF SHOWERS AND STORMS TO THE WEST WILL
TAPER THE FOG AT SITES LIKE UNV AND AOO, AS THERE WILL BE MORE
CLOUDS IN A FEW HOURS.
FOR MOST OF THE DAY, EXPECT SOME SHOWERS AND STORMS TO FORM
AGAIN, WITH A WIDE RANGE OF CONDITIONS.
NO REAL CHANGE TO THE PATTERN BEFORE THE MIDDLE OF NEXT WEEK.
THERE WILL BE A DAILY CHANCE OF SHOWERS AND STORMS OVER THE
NEXT FEW DAYS.
OUTLOOK...
SUN-TUE...FREQUENT RAIN SHOWERS; SOME LOCALLY HEAVY WITH
PROLONGED SUB-VFR CONDITIONS.
WED...SOME IMPROVEMENT EXPECTED WITH A DECREASING CHANCE OF
SHOWERS.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...STEINBUGL/BAUCO
NEAR TERM...BAUCO
SHORT TERM...STEINBUGL/BAUCO
LONG TERM...STEINBUGL/BAUCO
AVIATION...MARTIN
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