829
FXUS61 KCTP 101919
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
319 PM EDT MON AUG 10 2026
WHAT HAS CHANGED
* SVR TSTM WATCHES #552 AND #553 IN EFFECT THROUGH 21Z AND 23Z
RESPECTIVELY.
KEY MESSAGES
1) THUNDERSTORMS WITH SEVERE WIND GUSTS AND LOCALLY HEAVY RAIN
WILL BE LIKELY INTO EARLY THIS EVENING ACROSS PRIMARILY THE
LOWER SUSQ VALLEY
2) HUMID WITH ROUNDS OF HEAVY SHOWERS AND STRONG THUNDERSTORMS
FOCUSED OVER SOUTHWEST PENNSYLVANIA THROUGH MIDWEEK
DISCUSSION
KEY MESSAGE 1: THUNDERSTORMS WITH SEVERE WIND GUSTS AND LOCALLY
HEAVY RAIN WILL BE LIKELY INTO EARLY THIS EVENING ACROSS
PRIMARILY THE LOWER SUSQ VALLEY
3 PM EDT UPDATE: TSRA HAVE UNDERPERFORMED SO FAR TODAY, LIKELY
AS A RESULT OF THE AIRMASS UNABLE TO COMPLETELY RECOVER FROM
THE EARLY TO MID MORNING MCS AND SOME TRAILING CONVECTION THAT
MOVED QUICKLY ESE ACROSS CENTRAL PA AND THE LOWER SUSQ VALLEY.
NORTHERN, LEAD MCV IS EXITING OUR NE CWA ATTM AND OUR FOCUS WILL
TURN TO THE SCENT MTNS AND LOWER SUSQ VALLEY THROUGH 21Z, WHERE
FOCUSED SHEAR AND UVVEL AHEAD OF A SECOND MCV HAS LED TO THE
TALLEST REFL CORES OF THE DAY - PROMPTING THE ISSUANCE OF A FEW
SVRS AND ONE FFW.
WIDESPREAD MID AND UPPER LEVEL DEBRIS CLOUDS IN THE WAKE OF THIS
LINE WILL PREVENT SIGNIFICANT AIRMASS RECOVERY, EVEN THOUGH DEEP
LAYER SPEED AND DIRECTIONAL SHEAR (AND RESULTANT HODOGRAPHS)
ARE THE BEST THERE. SOME SCATTERED, STRONG STORMS ARE POSSIBLE
THERE, BUT LATEST HREF MEMBERS POINT TOWARD MAINLY A QUIET
EVENING ACROSS NW PA. BEST CHC FOR SHRA/TSRA LATER THIS EVENING
AND OVERNIGHT ARE ACROSS THE SW QUARTER OF PA.
WILL HAVE TO KEEP A CLOSE EYE ON THE EASTWARD EXTENT OF THE
NEXT, MCS TRACKING SE OVERNIGHT. A FURTHER EAST TRACK WOULD
PLACE PARTS OF OUR SW ZONES IN THE POTENTIAL OF HEAVY RAIN AND
FLASH FLOODING. FOR NOW, 6-12 PROBS FOR OVER 1 INCH OF RAIN
ACROSS CAMBRIA AND SOMERSET ARE QUITE LOW, SO WE'LL CONTINUE
WITH OUR HIGH CHC TO LOW LIKELY POPS AND A GLANCING BLOW WITH A
FEW TO SEVERAL TENTHS OF AN INCH OF RAIN, WITH THE REST OF THE
CWA SEEING GENERALLY LESS THAN 0.10 QPF FROM 11/00 TO 11/12Z.
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KEY MESSAGE 2: HUMID WITH ROUNDS OF HEAVY SHOWERS AND STRONG
THUNDERSTORMS FOCUSED OVER SOUTHWEST PENNSYLVANIA THROUGH
MIDWEEK
MODEL TRENDS ARE FOCUSING PRIMARY RISK FOR SEVERE STORMS AND
HEAVY RAIN ACROSS SOUTHWEST PA ON TUESDAY. THIS AREA LIES
CLOSEST TO THE EQUATORWARD EDGE OF THE WESTERLIES WITHIN VERY
MOIST INSTABILITY GRADIENT. SPC AND WPC HAVE OUTLOOKED THIS
AREA (SW PA) WITH A A LEVEL 2/5 SEVERE STORM RISK AND 2/4
EXCESSIVE RAIN RISK.
ROUNDS OF SHOWERS AND STORMS REMAIN POSSIBLE THROUGH MIDWEEK.
MULTIPLE SHORTWAVE DISTURBANCES WILL TRAVERSE THE NORTHERN TIER
AND INTERACT WITH A SLOW MOVING FRONTAL ZONE. THE COMBINATION
OF RICH LOW LEVEL MOISTURE, INSTABILITY AND REPEATED FORCING
ALONG THE BOUNDARY WILL SUPPORT SOME POTENTIAL FOR PERIODIC
CLUSTERS OF STORMS WITH LOCALLY HEAVY RAINFALL. WPC EXCESSIVE
RAIN OUTLOOKS (EROS) HAVE SHIFTED FARTHER TO THE SOUTH/WEST AND
ONLY CLIP THE FAR SOUTHWEST PORTION OF THE CWA ON DAYS 3-5 OR
WED-FRI.
THE END OF THE WEEK INTO THE START OF THE WEEKEND LOOKS LESS
HUMID (MORE REFRESHING) AS PUSH OF RELATIVELY COOLER AND DRIER
AIR ACCOMPANIES SEASONABLY STRONG/CANADIAN HIGH PRESSURE
BUILDING SOUTHEAST FROM THE UPPER MIDWEST.
AVIATION /19Z MONDAY THROUGH SATURDAY/
12Z TAF UPDATE: A LOOSELY ORGANIZED CLUSTER OF SHOWERS AND
THUNDERSTORMS IS MOVING ACROSS CENTRAL PA AS OF 1030Z, LOCATED
AROUND KJST/KAOO/KUNV, CORRESPONDING TO LIFT ALONG THE LEADING
EDGE OF HIGHER PWATS (UP TO AROUND 1.5") AND INSTABILITY (MUCAPE
TO 1000 J/KG). THIS ACTIVITY MAY CONTINUE INTO OUR EASTWARD
TERMINALS BETWEEN 12Z-14Z MONDAY (KMDT/KLNS, AND PERHAPS KIPT
DEPENDING THE NORTHERN EXTENT OF THIS CONVECTION), WITH
ADDITIONAL ROUNDS OF CONVECTION TO BE MONITORED LATER TODAY.
OTHERWISE, DISCUSSION POINTS REMAIN LARGELY THE SAME AS WITH THE
06Z TAF DISCUSSION PROVIDED BELOW.
PREVIOUS DISCUSSION: REMNANT MCS OVER WESTERN PA AS OF 06Z WILL
TRACK EASTWARD THROUGH THE MORNING HOURS, LIKELY DECAYING AS IT
ENCOUNTERS LIMITED INSTABILITY (MUCAPE OF 100-250 J/KG EAST OF
THE ALLEGHENY RIDGE). TIMING THIS FEATURE OUT ACROSS THE
TERMINALS, PROB30S FOR -TSRA WERE INCLUDED BETWEEN 08Z-14Z, WITH
CONFIDENCE STILL LOW REGARDING THE SYSTEM'S EVOLUTION.
RELATIVELY STEEP MID-LEVEL LAPSE RATES OF AROUND 6-7 C/KM WITH
EASTWARD EXTENT MAY ALLOW FOR THE SYSTEM TO PERSIST FOR LONGER,
WHILE RELATIVELY LIMITED MOISTURE (PWATS OF AROUND 1") AND THE
LOWER MUCAPE FAVOR A CONTINUED DOWNTREND. FOR THIS TIME, THE
FEATURE WAS TIMED OUT IN CASE IT PERSISTS.
LOW-LEVEL MOISTURE MAY SUPPORT A PERIOD OF MVFR CUMULUS AS THE
BOUNDARY LAYER DEEPENS DURING THE MORNING/AFTERNOON HOURS, WITH
HIGHER CONFIDENCE IN MVFR CEILINGS OVER OUR WESTERNMOST
TERMINALS (KBFD/KJST) & DECREASING CONFIDENCE WITH EASTWARD
EXTENT. OTHERWISE, THE MAIN WINDOW FOR AVIATION HAZARDS IS
EXPECTED TO BE THE AFTERNOON/EVENING FROM SCATTERED
THUNDERSTORMS, WITH MODERATE INSTABILITY (MLCAPE OF AROUND 1500
J/KG), DECENT SUPPORT FOR GUSTY DOWNDRAFT WINDS (DCAPE AROUND
1000 J/KG), AND FAVORABLE WIND SHEAR FOR ORGANIZED CONVECTION
(35 KTS OF 0-6 KM WIND SHEAR) IN PLACE. THIS PARAMETER SPACE
SUPPORTS MULTICELL CLUSTERS AND SQUALL LINES CAPABLE OF GUSTY TO
LOCALLY SEVERE WIND GUSTS. TIMING OF THESE POTENTIAL STORMS
WILL DEPEND ON UPSTREAM INITIATION AND ORGANIZATION, WITH COLD
POOL DEVELOPMENT POTENTIALLY ACCELERATING STORM MOTION.
STORM COVERAGE/INTENSITY IS EXPECTED TO DECREASE AFTER 00Z
TUESDAY, THOUGH ADDITIONAL SHOWERS/THUNDERSHOWERS CAN'T BE RULED
OUT. VFR IS CURRENTLY FAVORED AT MOST TERMINALS MONDAY NIGHT,
WITH THE MAIN EXCEPTION BEING KBFD WHERE ONSHORE FLOW FROM THE
GREAT LAKES MAY BRING RESTRICTIONS DUE TO LOW STRATUS AND MIST.
OUTLOOK...
MON-THU...SCATTERED SHOWERS/STORMS. RESTRICTIONS POSSIBLE.
FRI...MAINLY VFR. A FEW SHOWERS OR STORMS POSSIBLE OVER
SOUTHWESTERN PA.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...LAMBERT/STEINBUGL
KEY MESSAGES...LAMBERT/STEINBUGL
DISCUSSION...LAMBERT/STEINBUGL
AVIATION...TEARE
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