945
FXUS61 KCTP 302314
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
714 PM EDT SUN AUG 30 2026
WHAT HAS CHANGED
* INCREASED RAIN CHANCES ACROSS THE NORTHERN TIER THIS
AFTERNOON.
* LEVEL 2/SLIGHT SEVERE THUNDERSTORM RISK INTRODUCED FOR
TUESDAY (9/1)
KEY MESSAGES
1) LIGHT RAIN NORTH, SCATTERED THUNDERSTORMS SOUTHEAST TODAY
2) LATE SUMMER HEAT+HUMIDITY TO CLOSE AUGUST AND OPEN SEPTEMBER
3) BOUTS OF HEAVY RAIN & SEVERE STORMS POSSIBLE TUESDAY-
THURSDAY
DISCUSSION
KEY MESSAGE 1: LIGHT RAIN NORTH, SCATTERED THUNDERSTORMS
SOUTHEAST TODAY
AN ILL-DEFINED FRONT WILL CONTINUE TO DRIFT INTO CENTRAL PA THIS
AFTERNOON, BRINGING SOME WARM ADVECTION SHOWERS ACROSS THE
NORTHERN TIER. ALTHOUGH SHOWERS ARE EXPECTED TO WEAKEN WITH
EASTWARD EXTENT AS THEY ENCOUNTER SOME DRIER AIR, THE RADAR
PRESENTATION IS SHOWING NO SIGNS OF WEAKENING AND LIGHT RAIN IS
BECOMING INCREASINGLY LIKE ALONG AND NORTH OF I-80 THROUGH THE
AFTERNOON.
MEANWHILE, WE ARE STARTING TO SEE SOME CONVECTION INITIATION IN
THE LOWER SUSQUEHANNA VALLEY. 500 TO 750 J/KG OF MLCAPE WILL
PROVIDE SUFFICIENT FUEL FOR A FEW TALLER SHOWERS TO DEVELOP AND
PERHAPS SOME LIGHTNING. AS WE HEAD INTO THE OVERNIGHT HOURS, A
WAVE OF ENERGY DRIFTING ACROSS THE GREAT LAKES WILL BRING
MORE WIDESPREAD RAIN CHANCES INTO THE OVERNIGHT HOURS. ALL IN
ALL, RAINFALL TOTALS NORTH OF I-80 WILL BE BETWEEN A QUARTER AND
HALF INCH, WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. FARTHER
SOUTH, UP TO A QUARTER INCH IS POSSIBLE BUT LESS THAN A TENTH OF
AN INCH IS MOST LIKELY.
KEY MESSAGE 2: LATE SUMMER HEAT+HUMIDITY TO CLOSE AUGUST AND
OPEN SEPTEMBER
STRONG UPPER RIDGE EXPANDING EAST-NORTHEASTWARD FROM THE
SOUTH CENTRAL PLAINS THROUGH THE TN VALLEY INTO THE SOUTHERN
MID ATLANTIC AND SOUTHEAST STATES WILL DELIVER A STRETCH OF
ABOVE NORMAL LATE SUMMER WARMTH AND VERY HUMID CONDITIONS TO
CLOSE OUT AUGUST AND KICKOFF SEPTEMBER. FORECAST MAX/MIN
TEMPERATURES ARE PROJECTED TO RISE SEVERAL DEGREES ABOVE THE
HISTORICAL AVERAGE SUNDAY-THURSDAY WITH THE LARGEST DEPARTURE
FROM NORMAL (+10-20F) FOUND IN MIDWEEK OVERNIGHT LOWS. THE LATE
SUMMER HEAT IS FORECAST TO PEAK TUESDAY AND WEDNESDAY WITH MAX
HEAT INDICES APPROACHING ADVISORY LEVELS IN THE MID TO UPPER 90S
ACROSS PARTS OF SOUTH CENTRAL PA. THE WELL ABOVE NORMAL
TEMPERATURES COMBINED WITH HIGH HUMIDITY AND VERY WARM OVERNIGHT
LOWS WILL RESULT IN LEVEL 2 (MODERATE) TO LEVEL 3 (MAJOR)
HEATRISK VALUES TUESDAY AND WEDNESDAY. INCREASING TROUGHING
ACROSS THE NORTHEAST U.S. SHOULD DROP TEMPERATURES BACK TOWARD
SEASONAL CLIMO BY FRIDAY/SATURDAY.
KEY MESSAGE 3: BOUTS OF HEAVY RAIN AND SEVERE STORMS POSSIBLE
TUESDAY-THURSDAY
A SERIES OF MID LEVEL IMPULSES TRACKING EASTWARD ALONG THE
NORTHERN PERIPHERY OF THE ELONGATED 500MB RIDGE WILL INTERACT
WITH ANOMALOUS MOISTURE/INSTABILITY AND STRONG FLOW ALOFT TO
PRODUCE A FEW EPISODES OF HEAVY RAINFALL AND POSSIBLE SEVERE
WEATHER THROUGH LATE WEEK. THERE ARE TYPICAL TIMING AND
AMPLITUDE DIFFERENCES OF THE SMALLER SCALE DISTURBANCES THAT
WILL NEED TO BE RESOLVED, BUT THE OVERALL CONVECTIVE SIGNAL FROM
OPERATIONAL/ENSEMBLE/ML/AI GUIDANCE IS SUPPORTIVELY BULLISH.
THERE IS A GROWING SIGNAL FOR SEVERE STORMS AND HEAVY RAIN ON
TUESDAY THROUGH THURSDAY.
SPC INTRODUCED A LEVEL 2 SEVERE T-STORM RISK FOR D3/TUESDAY AND
D5/THURSDAY AND MAINTAINED THE 15% OR LEVEL 2 EQUIVALENT RISK
FOR D4/WEDNESDAY. WPC CONTINUES TO COVER PARTS OF CPA WITH LEVEL
1 EXCESSIVE RAINFALL OUTLOOKS WHICH MAY BE REFINED/UPGRADED AS
THE CONVECTIVE DETAILS BECOME MORE CLEAR AND CONFIDENCE IN
TIMING AND LOCATION INCREASES. THE ENVIRONMENT WILL BE
CHARACTERIZED BY IMPRESSIVE CAPE (ON THE ORDER OF 2-3K J/KG) AND
SUFFICIENT SHEAR. A CORRIDOR OF STRONG STORMS IS LIKELY
SOMEWHERE ACROSS UPSTATE NY INTO PA EACH DAY THROUGH THE WEEK,
WITH THE INITIATING BOUNDARY EACH DAY BEING HIGHLY DEPENDENT ON
THE EXTENT/INTENSITY OF STORMS THE DAY BEFORE. THE BATTLEGROUND BETWEEN
A HOT/HUMID/DRY DAY AND PERHAPS MULTIPLE ROUNDS OF STRONG
THUNDERSTORMS WILL LIKELY BE DRAPED SOMEWHERE ACROSS CENTRAL PA
THIS WEEK, SO THOSE WITH OUTDOOR PLANS SHOULD CONTINUE TO
MONITOR THE FORECAST CLOSELY.
AVIATION /00Z MONDAY THROUGH FRIDAY/
CEILINGS WILL GRADUALLY LOWER ACROSS NORTHERN PENNSYLVANIA
THROUGH THE NIGHT AS SHOWERS INCREASE IN COVERAGE IN ASSOCIATION
WITH A WAVE MOVING ACROSS THE GREAT LAKES. SOME GUIDANCE,
INCLUDING THE GLAMP, SHOW MVFR OR IFR CEILINGS DEVELOPING AT BFD
OVERNIGHT, BUT CONFIDENCE IS LOW ON THIS OCCURRING. THE HREF
SHOWS A LESS THAN 20 PERCENT CHANCE OF CEILINGS DROPPING TO IFR
AND SOUNDINGS FROM THE HRRR SUGGEST THAT VFR CEILINGS WILL
PERSIST THROUGH THE NIGHT. VISIBILITY RESTRICTIONS APPEAR MORE
LIKELY AT BFD, HOWEVER, AS RAIN DEVELOPS. MVFR OR IFR VISIBILITY
IS EXPECTED AT TIMES INTO THE MORNING. OUTSIDE OF BFD,
CONFIDENCE IS LOW ON HOW FAR SOUTH AND EAST SHOWERS MAKE IT
TONIGHT. IPT HAS THE NEXT HIGHEST CHANCE OF SEEING RAIN, BUT IT
IS CERTAINLY POSSIBLE THAT ALL TAF SITES SEE AT LEAST A BRIEF
SHOWER.
VFR CONDITIONS ARE FAVORED FOR MUCH OF THE DAY ON MONDAY,
THOUGH ADDITIONAL SHOWERS ARE EXPECTED TO DEVELOP DURING THE
LATE MORNING AND EARLY AFTERNOON. CONFIDENCE ON TIMING AND
PLACEMENT IS LOW, BUT IPT WOULD BE MOST LIKELY TO SEE IMPACTS
FROM RAIN. WINDS WILL GENERALLY BE LESS THAN 5 KNOTS.
OUTLOOK...
TUE-FRI...SCATTERED SHRA/TSRA WITH BRIEF RESTRICTIONS POSSIBLE;
MORNING FOG POSSIBLE.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...STEINBUGL/BANGHOFF
KEY MESSAGES...STEINBUGL/BANGHOFF
DISCUSSION...STEINBUGL/BANGHOFF
AVIATION...BAUCO
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