311
FXUS61 KCTP 022319
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
719 PM EDT FRI MAY 2 2025
SYNOPSIS
* PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY; SOME
STORMS MAY PRODUCE ISOLATED WIND DAMAGE, HAIL, AND LOCALLY
HEAVY RAINFALL
* 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 /THROUGH SATURDAY/
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE THROUGH
CENTRAL PA THIS EVENING. IN SPITE OF SUFFICIENT INSTABILITY,
WEAK SHEAR HAS LARGELY LIMITED STORMS FROM BECOMING SEVERE.
STILL, CAN'T RULE OUT A FEW STRONG WIND GUSTS OR MARGINALLY
SEVERE HAIL THROUGH THE REST OF THE EVENING.
HIRES MODELS INDICATE A LULL IN PRECIP IN THE 00-06Z WINDOW,
THEN SHOW A WAVE OF LOW PRESSURE BRINGING ANOTHER ROUND OF RAIN
ACROSS THE WESTERN/NORTHWEST ZONES DURING THE PREDAWN AND EARLY
MORNING HOURS SATURDAY. LOW REMAIN ON THE MILD SIDE OF CLIMO
WITH MIN TEMPS 50-60F OR +10-15F ABOVE NORMAL FOR EARLY MAY.
SHORT TERM /SATURDAY NIGHT 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/
LATE FRI EVENING UPDATE DOESN'T MAKE ANY CHANGES TO THE NEWEST
NBM GUIDANCE. THE CONFIDENCE IS NOW VERY HIGH FOR A VERY RAINY
PERIOD FOR ALMOST ALL OF THE LONG RANGE PERIOD. IT MAY DRY OUT
IN THE SECOND HALF OF THE WEEK, BUT SOME UNCERTAINTY EXISTS AS
TO HOW QUICKLY THE UPPER LOW MOVES TO THE EAST. CLOSED LOWS
USUALLY DON'T MOVE TOO QUICKLY, BUT MOST GUIDANCE DOES HAVE IT
MOVING EAST OF OUR LONGITUDE BY LATE WED OR THURSDAY AT THE
LATEST.
PREV...
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. MODELS SHOW THE UPPER LOW FEATURE FINALLY STARTING TO
ACCELERATE TO THE NORTHEAST AS IT INTERACTS WITH THE NORTHERN
STREAM FLOW, WHICH SHOULD RESULT IN DRIER CONDITIONS TOWARD
MIDWEEK.
AVIATION /23Z FRIDAY THROUGH WEDNESDAY/
VFR FLYING WITH BRIEF MVFR/IFR RESTRICTIONS DUE TO SCATTERED
SHOWERS AND T-STORMS THROUGH 00Z. A FEW STRONG TO SEVERE STORMS
ARE POSSIBLE ACROSS THE FAR NORTHWEST PORTION OF THE AIRSPACE.
DUE TO THE TRANSIENT NATURE OF CONVECTION, HAVE ACCOUNTED FOR
T-STORM IMPACTS THROUGH PROB30S AT ALL TAF SITES. THERE IS A
STRONG SIGNAL FOR LIFR LATE TONIGHT INTO SATURDAY MORNING AT
KBFD WITH ANOTHER ROUND OF RAIN PROBABLE AFTER 06Z.
OUTLOOK...
SAT...PERIODS OF RAIN/SHOWERS; ISOLATED STRONG TO SVR T-STORMS
POSSIBLE ACROSS THE SOUTHEAST 1/2 OF THE AIRSPACE.
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
NEAR TERM...STEINBUGL/BAUCO
SHORT TERM...STEINBUGL/BAUCO
LONG TERM...DANGELO/STEINBUGL
AVIATION...STEINBUGL
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