302
FXUS61 KCTP 051031
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
631 AM EDT MON MAY 5 2025
SYNOPSIS
* SLOW MOVING, TRAINING SHOWERS AND PM THUNDERSTORMS WILL LEAD
TO LOCALIZED HEAVY RAINFALL OF 1 TO 2+ INCHES WITH THE
POTENTIAL FOR SMALL STREAM AND POOR DRAINAGE FLOODING IN A FEW
LOCATIONS ACROSS CENTRAL PENNSYLVANIA AND THE WESTERN MTNS.
*BECOMING DRIER LATE IN THE WEEK WITH A TREND TOWARD BELOW
NORMAL TEMPERATURES.
NEAR TERM /THROUGH TONIGHT/
A QUASI-STNRY FRONT STRETCHED ABOUT 25 NM EITHER SIDE OF
INTERSTATE 80 (ALONG ITS ENTIRE LENGTH THROUGH PA) HAS HELPED
TO STRENGTHEN SEVERAL NARROW BANDS OF SHOWERS OVERNIGHT AS THEY
DRIFTED NNW OVER THE BOUNDARY THAT PROVIDED SOME ENHANCED MESO-B
LIFT.
AS WE HEAD THROUGH THE LATE MORRING AND INTO THE AFTERNOON HOURS,
THE FOCUS FOR THE MOST NUMEROUS BANDS OF CONVECTION AND THREAT
FOR HEAVIEST RAIN AND LOCALIZED SEVERE WEATHER WILL BE ACROSS
THE APPROX SW 1/2 OF THE CWA TODAY AS 2 SEPARATE MID/UPPER LEVEL
JET MAXES/LOBES OF DIFFERENTIAL VORT LIFT NORTH ACROSS THE
WESTERN AND CENTRAL MTNS. SLIGHTLY LOWER PROBS FOR SEVERE
WEATHER AND TRAINING HEAVY SHRA/TSRA EXIST ACROSS THE MIDDLE
SUSQ VALLEY AND ENDLESS MTNS REGION NE OF KIPT.
THE FIRST OF THE AFOREMENTIONED KINEMATIC FEATURES ALOFT WILL BE
THE ENHANCED LIFT/FOCUS FOR THE INITIAL TSRA BENEATH THE RIGHT
ENTRANCE REGION OF A UPPER LEVEL SPEED MAX STRETCHED FROM KPIT
TO KCLE LATE THIS MORNING THROUGH EARLY THIS AFTERNOON, FOLLOWED
BY A LINK WITH MESO-B UVVEL BENEATH THE LEFT EXIT REGION OF
ANOTHER SOUTHERLY JET SEGMENT DRIFTING NORTH ACROSS VA AND THE
MD PANHANDLE TOWARD EVENING.
A DISTINCT CHANNEL OF ENHANCED (DEEP AND SOMEWHAT THIN) CAPE OF
1000-1500 J/KG WILL EXIST BETWEEN RT 219 IN THE WESTERN MTNS
AND RT 15 NORTH THROUGH THE SUSQ VALLEY.
LATER SHIFTS WILL NEED TO KEEP A CLOSE EYE ON THE EVOLUTION OF
CONVECTION AND TRAINING CELLS WITHIN THIS PART OF THE CWA (WHICH
COVERED BY WPC'S MRGL RISK OF EXCESSIVE RAIN), AS PWAT VALUES
WILL BE JUST UNDER 1.5 INCHES COINCIDING WITH SOUNDINGS THAT
INDICATE A DEEP, MOIST, WARM CLOUD LAYER UP THROUGH 11-13 KFT
AGL LEADING TO HIGHLY EFFICIENT RAINFALL PRODUCTION. A SHORT-
FUSED FLOOD WATCH MAY NEED TO BE COLLABORATED/ISSUED AT SOME
POINT LATER THIS MORNING/AFTERNOON.
MAX TEMPS WILL DISPLAY A SMALL RANGE TODAY (ONLY ABOUT 5-6 DEG
F) FROM THE UPPER 60S TO LOW 70S. A FEW SPOTS THROUGHOUT SCENT
PA COULD SEE A 74 OR 75F THIS AFTERNOON.
SPC MAINTAINS A MRGL RISK FOR STRONGER UPDRAFTS CONTAINING 1
INCH HAIL AND LOCALLY DAMAGING WIND GUSTS. AS NOTED BY EARLIER
SHIFTS, ALTHOUGH NOT OUTLOOKED FOR TORNADOES, A BRIEF, WEAK
TORNADO CAN NOT BE RULED OUT GIVEN THE LOW LCLS AND SUFFICIENT
VEERING/MODERATELY STRONG LLVL SPEED SHEAR WITHIN THE WIND
PROFILE AT LOW LEVELS.
CONVECTION MAY BE SLOW TO WANE TONIGHT, WITH BOTH THE NAM AND
HRRR SHOWING POTENTIAL FOR NARROW SWATHS OF 1-2" OF RAIN FALLING
FROM MATURE CONVECTIVE LINES AND CLUSTERS IN JUST THE 12 HOUR
PERIOD FROM 00Z-12Z TUE.
SHORT TERM /TUESDAY THROUGH WEDNESDAY/
ACTIVE WEATHER WILL LIKELY CONTINUE TUESDAY/TUESDAY EVENING AS
THE CORE OF THE UPPER LOW MOVES INTO WESTERN PA. THIS WILL PUSH
THE HIGHEST INSTABILITY AND GREATEST CHANCE FOR SEVERE WEATHER
EAST INTO THE LOWER SUSQUEHANNA VALLEY.
THE THREAT FOR SEVERE WEATHER APPEARS TO DECREASE WEDNESDAY AS
THE SLOW MOVING UPPER LOW GRADUALLY FILLS IN AND THE CENTER
MOVES ACROSS THE EASTERN THIRD OF THE STATE IN THE AFTERNOON,
WITH PRECIP LIKELY COMING TO AN END ACROSS THE BULK OF CENTRAL
PA BY WED EVENING.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
BY THE LATTER HALF OF THE WEEK, THE UPPER LOW WILL BE REPLACED
BY A FAIRLY POTENT UPPER TROUGH AS HIGH PRESSURE BUILDS IN AT
THE SURFACE. MUCH LOWER PWATS (0.25 - 0.75") WILL USHER IN A
STRETCH OF COOLER AND LESS-RAINY CONDITIONS FOR THE WEEKEND.
COOL TEMPS ALOFT WILL KEEP A CHANCE FOR DIURNAL SHOWERS IN THE
FORECAST EACH AFTERNOON, BUT ENSEMBLE MEAN RAINFALL FOR THE
PERIOD IS LESS THAN A QUARTER INCH ACROSS THE WHOLE AREA.
HIGH PRESSURE AMIDST A COOLER AIRMASS WILL SUPPORT A RISK FOR
FROST FRIDAY AND SATURDAY MORNING, ESPECIALLY WEST OF I-99 AND
NORTH OF I-80. THE GROWING SEASON IS CURRENTLY ACTIVE FOR ONLY
THE COUNTIES ALONG/EAST OF I-99 AND ALONG/SOUTH OF I-80, BUT AS
WE APPROACH THE MEDIAN DATE OF THE FIRST FREEZE FOR MUCH OF THE
LAUREL HIGHLANDS AND NORTHWEST MOUNTAINS (MAY 11TH),
FROST/FREEZE PRODUCTS MAY BE NEEDED THERE LATER THIS WEEK.
AFTER THE BRIEF COOL SNAP THURSDAY NIGHT THROUGH FRIDAY NIGHT,
ENSEMBLES FAVOR A RETURN TO NEAR NORMAL TEMPERATURES WITH HIGHS
IN THE 60S TO 70S AND LOWS IN THE 40S TO 50S.
AVIATION /12Z MONDAY THROUGH FRIDAY/
NOT A BAD MORNING SO FAR, NOT MUCH LEFT ON THE RADAR. THIS
HAS RESULTED IN ENOUGH CLEARING FOR SOME PATCHY FOG IN
SPOTS AT SUNRISE. STILL EXPECT FOG TO BE LIMITED IN SPACE AND
TIME.
EARLIER DISCUSSION BELOW.
LIKE LAST NIGHT, CONDITIONS IN MANY LOCATIONS NOT QUITE AS
LOW AS FCST SO FAR. HOWEVER, EXPECT A WIDE RANGE OF CONDITIONS
OVERNIGHT INTO AT LEAST TUESDAY, WITH CLUSTERS OF SHOWERS AND
ISOLATED THUNDERSTORMS AT TIMES.
SPEAKING OF THUNDER, HAD A STORM FORM JUST EAST OF THE OFFICE
HERE AROUND 11 PM AND IS NOW TO THE NORTH. CELL MOVEMENT IS
FROM THE SOUTH.
SOME SHOWERS AND STORMS WILL HAVE HEAVY DOWNPOURS INTO TUESDAY.
GUSTY WINDS AND SMALL HAIL POSSIBLE, BUT MORE ON THE ISOLATED
SIDE.
CONDITIONS COULD BE A BIT BETTER BY MID WEEK, AS LOWER DEWPOINTS
WORK IN. HOWEVER, TREND WITH TIME HAS HINTED THAT THE UPPER
LEVEL PATTERN MAY END UP KEEPING SOME SHOWERS AROUND ALL WEEK.
OUTLOOK...
TUE...FREQUENT RAIN SHOWERS; SOME LOCALLY HEAVY WITH PROLONGED
SUB-VFR CONDITIONS. CHANCE OF TSRA/CB.
WED-FRI...SHOWERS BECOME MORE SCATTERED WITH HIGHER CHANCES IN
THE AFTERNOON/EVENING HOURS. RESTRICTIONS POSSIBLE.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/BANGHOFF/COLBERT
LONG TERM...BANGHOFF
AVIATION...MARTIN
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