044
FXUS61 KCTP 080904
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
504 AM EDT THU MAY 8 2025
SYNOPSIS
*SHOWERS AND A COUPLE OF THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL ACROSS SOUTH CENTRAL PA THIS AFTERNOON AND EVENING
*COOLER END TO THE WEEK WITH PERIODS OF RAIN/SHOWERS FRIDAY
ENDING FROM SOUTHWEST TO NORTHEAST FRIDAY NIGHT-AM SATURDAY
*RAIN-FREE AND PLEASANT CONDITIONS THROUGH MOTHER'S DAY WEEKEND
NEAR TERM /THROUGH TONIGHT/
IR SAT TRENDS SHOW HIGH CLOUDS HAVE PEELED AWAY ACROSS THE
SOUTHERN 3/4 OF THE FORECAST AREA; THIS IS BULLISH FOR AREAS OF
VALLEY FOG TO DEVELOP THROUGH SUNRISE UNDER MORE IDEAL
RADIATIONAL COOLING. THE LATEST OBSERVATIONAL TRENDS 08-09Z
INDICATE A HYBRID FOG/STRATUS PATTERN DEVELOPING BEHIND THE SFC
COLD FRONT OVER THE NORTHERN TIER.
A COMPLEX UPPER-LEVEL EVOLUTION WILL BEGIN TODAY AND PORTEND
MORE WET WX THROUGH THE END OF THE WEEK. A POSITIVELY TILTED
UPPER TROUGH WILL SPLIT/BREAK INTO A COLD CLOSED 500MB LOW BY
TONIGHT OVER WESTERN PA. THIS LARGE SCALE PATTERN TRANSITION
WILL SLOW THE SOUTHEASTWARD PROGRESS OF THE AFOREMENTIONED COLD
FRONT, SETTING UP A TRIGGERING MECHANISM OR FOCUS FOR DIURNAL
CONVECTION ACROSS SOUTH CENTRAL PA THIS AFTERNOON AND EVENING.
THE AIRMASS ALONG AND TO THE SOUTH/EAST OF THE COLD FRONT WILL
BE ONLY MARGINALLY UNSTABLE, BUT FAIRLY MOIST WITH PWS 1-1.25
INCHES OVER THE LOWER SUSQUEHANNA VALLEY. THE 08/00Z HREF PMM
SHOWS THE HIGHEST NEIGHBORHOOD PROBS FOR >1"/3HR ALONG AND TO
THE SOUTHEAST OF I-81. SOIL SENSITIVITY IS RATHER VARIABLE OVER
THIS AREA BASED ON THE ONGOING DROUGHT CONDITIONS AND 3HR FFG
VALUES. THERE IS SOME SPREAD IN THE HIRES QPF AMOUNTS AND
LOCATIONS.
AN ISOLATED SHORT TERM FLOODING RISK WILL REMAIN HIGHLY
DEPENDENT ON EXACTLY WHERE THE HEAVY RAIN FALLS; AREAS THAT HAVE
EXPERIENCED EXCEPTIONALLY HIGH SOIL SATURATION/SENSITIVITY AND
ELEVATED SMALL STREAM FLOWS OVER THE PAST SEVERAL DAYS WOULD BE
MOST AT RISK. ADDITIONAL RAIN IS EXPECTED ACROSS THE SOUTHEAST
HALF OF THE CWA OVERNIGHT INTO EARLY FRIDAY MORNING AS A FRONTAL
WAVE RIDES NORTH ALONG THE QUASI-STATIONARY BOUNDARY.
THE NORTHERN TIER WILL SEE A NOTICEABLE COOL DOWN OF -10
DEGREES VS. YESTERDAY IN BOTH MAX (55-60F) AND MIN TEMPS
(40-45F).
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
THE SLOW MOVING, CLOSED 500MB LOW WILL TRACK ALONG THE MD LINE
ON FRIDAY BEFORE REACHING THE NYC AREA BY 12Z SATURDAY. BROAD
SYNOPTIC LIFT AND FGEN/DEFORMATION WILL DRIVE FAIRLY WIDESPREAD
SHOWER ACTIVITY TO END THE WEEK. CLOUDY, COOL AND WET
CONDITIONS ARE EXPECTED OVER MOST OF CPA WITH A ~10F SETBACK IN
DAYTIME HIGHS ACROSS THE BOARD. THIS TRANSLATES TO MAX TEMPS IN
THE 50-65F RANGE OR 10-15F BELOW CLIMO ACROSS THE SOUTHERN 3/4
OF THE CWA. WE WILL NEED TO MONITOR POTENTIAL COMMA HEAD WRAP
AROUND PRECIP WHICH MAY SETUP OVER A LONGER DURATION AND PIVOT
ACROSS THE NORTHEAST ZONES WHICH HAVE SOME OF THE LOWEST FFGS IN
THE CWA. THANKFULLY, IT APPEARS THAT ADDITIONAL RAINFALL ON
FRIDAY WILL BE MORE OF A STEADIER, LIGHT TO MODERATE INTENSITY.
THE LATEST MODEL TIMING IS FOR RAIN TO END FROM SOUTHWEST TO
NORTHEAST BY 12Z SATURDAY AS THE FRONTAL SYSTEM LIFTS AWAY AND
ACCELERATES TO THE NORTHEAST ALONG THE NEW ENGLAND COAST. HIGH
PRESSURE BUILDING INTO CPA WILL PROVIDE A BEAUTIFUL AND RAIN-
FREE START TO MOTHER'S DAY WEEKEND WITH LOW HUMIDITY.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
A REALLY NICE MOTHER'S DAY SHAPING UP ACROSS CPA WITH SUNSHINE
AND WARMER TEMPS IN THE 65-75F RANGE. AS HIGH PRESSURE MOVES
OFF THE EAST COAST MON, RETURN FLOW WILL USHER IN INCREASING
MOISTURE FOR MON-TUE. LONGER RANGE GUIDANCE SUGGESTS A DEEP
LONGWAVE TROUGH IN THE SOUTHERN BRANCH OF THE JET STREAM THAT
MAY BRING UNSETTLED WEATHER ONCE AGAIN BY NEXT WEEK.
AVIATION /07Z THURSDAY THROUGH MONDAY/
LIGHT WIND AND COOLING OF THE MOIST GROUND WILL CREATE LOCALLY
DENSE FOG AND A SEVERAL HOUR PERIOD OF LOW CIGS LATER TONIGHT
INTO THE MID MORNING HOURS ON FRIDAY, ESPECIALLY WHERE RAN FELL
THE LAST TWO DAYS. THE CHANCE FOR FOG IS HIGHEST AT BFD AND JST
(50-60 PCT CHANCE) WITH CHANCES DROPPING TO 30-40 PCT INTO
AOO, UNV, AND IPT, AND LESS THAN 30 PCT AT LNS AND MDT. VSBY IS
EXPECTED TO IMPROVE BETWEEN 12-14Z THU.
LAYERED STRATUS AND STRATOCU WILL SPREAD EAST ACROSS THE REGION
DURING THE LATE MORNING (NW) THROUGH MID HOURS (SE) WITH
SHOWERS AND PERHAPS TSRA IN THE AFTERNOON (MAINLY ACROSS THE SE
HALF OF PA). CIGS UNDER A LIGHT NORTHERLY FLOW COULD DIP
INTO/OR STAY IN THE IFR TO LOW IFR RANGE FOR THE LATE MORNING
AND EARLY AFTERNOON AT KBFD AND KJST, WHILE OTHER AIRFIELDS IN
THE CENTRAL RIDGE AND VALLEY REGION WILL DEAL WITH MAINLY
PERIODS OF MVFR OR LOW END VFR CIGS THROUGH THE DAY THURSDAY
ALONG WITH A RELATIVELY LIGHT NORTH TO NNE BREEZE. RESTRICTIONS
IN PERIODS OF RAIN ARE POSSIBLE THU NIGHT INTO THE FIRST HALF
OF FRI, WITH IMPROVEMENT FROM NW TO SE LATER FRI.
OUTLOOK...
SAT-SUN...NO SIG WX.
MON...SLGT CHC -SHRA ACROSS THE SOUTH
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...LAMBERT/COLBERT/BAUCO
AVIATION...LAMBERT/COLBERT
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