717
FXUS61 KPBZ 012325
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
725 PM EDT TUE SEP 1 2026
WHAT HAS CHANGED
A HEAT ADVISORY HAS BEEN ISSUED FOR WEDNESDAY, SEPTEMBER 2.
UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
1) ADDITIONAL SHOWER AND THUNDERSTORM CHANCES AT TIMES THROUGH
LATE WEEK, WITH SOME POSSIBILITY FOR SEVERE STORMS.
2) HEAT AND HUMIDITY BUILD THROUGH THURSDAY. HEAT ADVISORY
ISSUED FOR WEDNESDAY, SEPTEMBER 2.
DISCUSSION
KEY MESSAGE 1...
THE 500MB RIDGE OVER THE CENTRAL CONUS WILL SHIFT EAST AS
NORTHWEST FLOW SETS UP OVER THE GREAT LAKES AND INTO THE UPPER
OHIO VALLEY. THIS WILL SET UP A SERIES OF SHORTWAVES TO TRAVEL
SOUTHEAST OVER THE REGION THE NEXT FEW DAYS. THE TIMING OF THE
SHORTWAVES OVER THE NEXT FEW DAYS WILL BE THE MAIN ISSUE AS HI-
RES MODELS AND ENSEMBLES ARE NOT HANDLING THE SETUP VERY WELL
IN THE TIMING AND PLACEMENT.
THERE IS A CONDITIONAL POTENTIAL FOR SEVERE STORMS TODAY. IF
STORMS CAN DEVELOP, THE ML CAPE BETWEEN 2000-3000 J/KG AND
25-30KT 0-6 KM SHEAR WOULD SUPPORT SEVERE STORMS. HOWEVER,
CONSENSUS IN THE MODELS SUGGESTS A MORE EARLY WEDNESDAY MORNING
THREAT WITH THE POTENTIAL DEVELOPMENT OF STORMS MOVING IN OFF
THE GREAT LAKES.
THERE WILL BE A SECOND THREAT WEDNESDAY DURING THE LATE
AFTERNOON AND EVENING. CURRENT INDICATIONS ARE THE RIDGE SHOULD
BEGIN TO BREAK DOWN LATE WEDNESDAY AND THURSDAY, AS A SHORTWAVE
AND SURFACE COLD FRONT APPROACHING. THE POTENTIAL FOR SEVERE
STORMS WILL ALSO INCREASE BY WEDNESDAY EVENING, INCREASING AGAIN
ON THURSDAY AS CONVECTION INCREASES IN DIURNAL HEATING ALONG
THE SLOW MOVING FRONT. INCREASING NW FLOW ALOFT SHOULD RESULT IN
INCREASED SHEAR AND DIURNAL INSTABILITY. THE POTENTIAL
CONTINUES FOR SEVERE STORMS INTO THURSDAY. THE LATEST ML
GUIDANCE INDICATES THE INCREASING SEVERE POTENTIAL, ESPECIALLY
LATE WEDNESDAY AND THURSDAY.
KEY MESSAGE 2...
A 500MB RIDGE EXTENDING OVER THE GREAT LAKES AND OHIO RIVER
VALLEY WILL HELP BRING IN THE WARMER TEMPERATURES THROUGH
THURSDAY. THE HEAT SHOULD PEAK WEDNESDAY WITH HIGHS IN THE
UPPER 80S TO LOWER 90S FOR MOST AREAS. THIS COMBINED WITH HIGHER
HUMIDITY IS LIKELY TO RESULT IN HEAT INDEX VALUES IN THE UPPER
90S TO 100 WEDNESDAY. A HEAT ADVISORY WAS ISSUED FOR EASTERN
OHIO, MOST OF NORTHERN WEST VIRGINIA, AND SOUTHWESTERN PA FOR
AREAS THAT ARE LIKELY TO REACH HEAT INDICES OF 100F.
HEAT IS FORECAST TO LINGER INTO THURSDAY AS THE 500MB RIDGE
WEAKENS AND MOVES SOUTHEASTWARD. TEMPERATURES IN THE UPPER 80S
AND LOWER 90S WITH HEAT INDICES IN THE UPPER 90S IS EXPECTED. A
TROUGH MOVING INTO THE AREA BEHIND THE RIDGE WILL BRING CLOUD
COVER AND THE CHANCE FOR SHOWERS/STORMS WHICH COULD INHIBIT
DAYTIME HEATING.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AN ONGOING CLUSTER OF STORMS MOVING TOWARDS DUJ CAN BRING BRIEF
MVFR TO IFR RESTRICTIONS BUT ALL OTHER PORTS ARE EXPECTED TO
BEGIN THE TAF PERIOD WITH A LONG STRETCH OF VFR CONDITIONS.
MODELS CONTINUE TO FAVOR RECURRING RESTRICTIONS AT DUJ, COMING
NEXT IN THE FORM OF POSSIBLE LOW LEVEL FOG OR STRATUS BEFORE
SUNRISE RESULTING FROM SOME LOW-LEVEL CONVERGENCE AND RECENT
MOISTURE IN THE GROUND. AFTER THIS, MODELS CONTINUE TO HINT AT
THE POSSIBILITY OF ANOTHER THUNDERSTORM COMPLEX RUMBLING ACROSS
THE REGION AND CLIPPING FKL/DUJ BETWEEN 10Z-14Z TOMORROW
MORNING, THOUGH INTENSITY OF SUCH SYSTEM IS UNCERTAIN. IF NEAR
PEAK STRENGTH, HEAVY RAIN SIGNIFICANTLY REDUCING VISIBILITIES
AND GUSTY WIND AROUND/GREATER THAN 30KTS CAN BE EXPECTED.
MUCH OF THE TAF WINDOW WILL BE VFR FOR MANY PORTS, SAVE FKL/DUJ.
STORM CHANCES NEAR THE END OF THE CURRENT TAF PERIOD ARE
DIFFICULT TO PIN DOWN. THERE IS LOWER THAN USUAL CONFIDENCE IN
THIS CURRENT SETUP. STORM CHANCES EXIST TOMORROW AFTERNOON BUT
GIVEN A WIDE ARRAY OF OUTCOMES IN TERMS OF COVERAGE AND
INTENSITY, THESE STORMS HAVE NOT BEEN MENTIONED IN THE CURRENT
TAF.
OUTLOOK...
SHORTWAVE MOVEMENT ALONG THE NORTHERN PERIPHERY OF THE RIDGE
COULD CREATE SHORT PERIODS THROUGH THE WEEK WHERE
SHOWERS/THUNDERSTORMS MAY OCCUR. DUE TO DIFFICULTIES MODELING
THESE FEATURES, TIMING/COVERAGE OF STORM POTENTIAL MAY BE
DIFFICULT UNTIL 6-12 HOURS BEFORE ARRIVAL AND CAUSE LARGER-
THAN-NORMAL FLUCTUATIONS IN TAF STORM TIMING. ADDITIONALLY,
STORM ENVIRONMENTS MAY BE CONDUCIVE TO GUSTY, ERRATIC WINDS PLUS
HEAVY DOWNPOURS THAT COULD CONTRIBUTE TO RESTRICTION
DEVELOPMENT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY FROM 8 AM TO 8 PM EDT WEDNESDAY FOR PAZ013-014-
020>022-029-031-073-075.
OH...HEAT ADVISORY FROM 8 AM TO 8 PM EDT WEDNESDAY FOR OHZ039>041-
048>050-057>059-068-069.
WV...HEAT ADVISORY FROM 8 AM TO 8 PM EDT WEDNESDAY FOR WVZ001>004-
012-021-509.
DISCUSSION...SHALLENBERGER/LUPO
AVIATION...FRAZIER/AK
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