745
FXUS61 KPBZ 100626
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
226 AM EDT MON AUG 10 2026
WHAT HAS CHANGED
THE OVERALL FORECAST REMAINS THE SAME, AND CONFIDENCE IN DETAILS
OF TIMING AND LOCATION OF STRONGEST STORMS REMAINS FAIRLY LOW.
KEY MESSAGES
1) DAILY SHOWER AND THUNDERSTORM CHANCES RETURN TODAY AND
REMAIN IN THE FORECAST THROUGH AT LEAST THURSDAY WITH BOTH THE
POTENTIAL FOR STRONG/SEVERE STORMS AND HEAVY RAINFALL.
DISCUSSION
KEY MESSAGE 1...
A CONVECTIVE LINE CROSSING NORTH OF PITTSBURGH, THE REMNANTS OF
EARLIER STOUT STORMS, ARE PRODUCING MAINLY BRIEF HEAVY RAIN AND
WIND GUSTS OF UP TO 40 MPH AS THEY CROSS. THESE, AS WELL AS
WEAKER ACTIVITY TO THE SOUTH, SHOULD EXIT TO THE EAST BY
SUNRISE.
AFTER A BRIEF BREAK LATER THIS MORNING, ADDITIONAL CONVECTION IS
LIKELY TO ARRIVE BY MIDDAY/EARLY AFTERNOON, LIKELY THE
CONTINUATION OF ACTIVITY CURRENTLY NEAR THE SOUTHERN END OF
LAKE MICHIGAN. ANOTHER ROUND IS THEN POSSIBLE AFTER SUNSET WITH
A SHORTWAVE PASSAGE. WHILE EXACT TIMING AND EVOLUTION OF
AFTERNOON/EVENING CONVECTION REMAINS IN QUESTION, THERE IS STILL
A DECENT LEVEL OF CONFIDENCE IN THE PRESENCE OF AN ENVIRONMENT
CONDUCIVE FOR SEVERE STORMS. MODEL SOUNDINGS SUGGEST MEAN-LAYER
CAPE VALUES WILL BE IN THE 1500 TO 2000 J/KG RANGE DURING THE
PEAK HEATING PERIOD, WITH DEEP-LAYER SHEAR ON THE ORDER OF 25 TO
35 KNOTS. THIS WILL SUPPORT ORGANIZED CONVECTION WITH MAINLY A
DAMAGING WIND THREAT, BOTH FROM COLD POOL CONSOLIDATION AND
DOWNBURST POTENTIAL (DCAPE OF AROUND 1000 J/KG). SOME AT LEAST
TRANSIENT SUPERCELL STRUCTURES/ROTATING STORMS ARE ALSO
POSSIBLE, THUS THE THREAT FOR A TORNADO OR TWO CANNOT BE
IGNORED.
FOR TUESDAY (AND POTENTIALLY WEDNESDAY AS WELL), THE MAIN THREAT
CORRIDOR SHIFTS SOUTH A BIT, WITH THE BEST POTENTIAL FOR SEVERE
STORMS MAINLY SOUTH OF I-70 (MATCHING SPC'S DAY 2 SLIGHT RISK
AREA). THIS IS WHERE RICHER INSTABILITY WILL RESIDE DURING THE
AFTERNOON AND EVENING. AGAIN, DAMAGING WINDS APPEAR TO BE THE
PRIMARY THREAT, AS THIS MAY BE THE MORE FAVORED REGION FOR
CONVECTIVE COMPLEX PASSAGE. THE MORE CONCENTRATED WIND DAMAGE
THREAT AREA LIKELY REMAINS JUST TO THE SOUTH OF OUR REGION, BUT
COULD CLIP PORTIONS OF AT LEAST EASTERN OHIO.
IN ADDITION TO SEVERE THREATS, THERE REMAINS THE RISK OF FLASH
FLOODING. GIVEN PRECIPITABLE WATER VALUES LIFTING BACK INTO THE
1.6 TO 1.7 INCH RANGE (90TH TO 95TH PERCENTILE IN THE
CLIMATOLOGY), AS WELL AS THE POTENTIAL FOR MULTIPLE THUNDERSTORM
COMPLEXES, WPC CONTINUES TO HIGHLIGHT OUR REGION IN A SLIGHT
(LEVEL 2 OF 4) RISK FOR EXCESSIVE RAIN FOR TODAY INTO TUESDAY
NIGHT, WITH THE MAIN HEAVY RAIN THREAT AREA SHIFTING SOUTH OF
THE MASON-DIXON LINE BY WEDNESDAY. 48-HOUR NBM MEAN
PRECIPITATION TOTALS ARE IN THE 1.5 TO 2.5 INCH RANGE GENERALLY
SOUTH OF US-422, WITH 90TH PERCENTILE TOTALS IN THE SAME AREA OF
3 TO 4 INCHES. GIVEN THE STILL RELATIVELY MOIST SOIL ACROSS THE
REGION, SUCH RAINFALL TOTALS COULD CREATE AT LEAST ISOLATED
FLASH FLOODING ISSUES IN THE HEAVIER CONVECTION. STILL, WITH THE
UNCERTAINTY IN TIMING AND LOCATION OF THE GREATEST POTENTIAL,
WILL HOLD OFF ON THE ISSUANCE OF A FLOOD WATCH AT THIS TIME.
BY THURSDAY, BOTH HEAVY RAIN AND SEVERE WEATHER THREATS SHOULD
BEGIN TO SUBSIDE AS A STRONGER GREAT LAKES SHORTWAVE PUSHES A
BOUNDARY ACROSS THE AREA, LEADING TO LESS THREATENING WEATHER.
AVIATION /06Z MONDAY THROUGH FRIDAY/
VFR IS GENERALLY FAVORED OUTSIDE OF CONVECTIVE PERIODS, THOUGH
DIURNAL HEATING/MIXING BETWEEN 13Z-18Z MONDAY MAY YIELD BRIEF
MVFR CU.
CURRENT THUNDERSTORM LINE NORTH OF PITTSBURGH SHOULD AFFECT DUJ
BRIEFLY WITH IFR VISIBILITY IN HEAVY RAIN, AS WELL AS A WIND
GUST TO 30 KNOTS. TIMING OF FUTURE THUNDERSTORM COMPLEXES
REMAINS TRICKY TODAY. TWO GENERAL ROUNDS ARE FORESEEN DURING THE
TAF PERIOD: ONE FROM 14Z TO 20Z, ASSOCIATED WITH CURRENT
SOUTHERN GREAT LAKES STORMS, AND ANOTHER MAINLY AFTER 00Z WITH A
SHORTWAVE PASSAGE. THESE DETAILS ARE SUBJECT TO CHANGE AS THE
MESOSCALE ENVIRONMENT EVOLVES. IN ANY CASE, STORMS WILL BE
CAPABLE OF BRIEF IFR TO LIFR VISIBILITY AS WELL AS GUSTY WIND -
PERHAPS TO BETWEEN 40 AND 50 KNOTS PEAK IN THE STRONGEST STORMS,
AND EVEN HAIL IS A POSSIBILITY. SUCH WINDS ARE MORE LIKELY WITH
THE DAYTIME ACTIVITY AS OPPOSED TO THE EVENING STORMS. THE
CURRENT TAFS REPRESENT BEST GUESS TIMING BASED ON LATEST
AVAILABLE DATA BUT IS OF LOW CONFIDENCE.
OUTLOOK... ACTIVE WEATHER THROUGH MUCH OF THE WEEK WITH VARYING
ROUNDS OF SHOWERS AND THUNDERSTORMS. TIMING OF STORMS FOR A
GIVEN DAY IS LIKELY TO BE OF LOWER CONFIDENCE AND DEPENDENT ON
UPSTREAM STORM PROGRESSION. MOST RESTRICTIONS DURING THIS PERIOD
WILL BE TIED TO STORM ACTIVITY AND/OR MORNING FOG/STRATUS
RESULTANT OF RAIN PLUS OVERNIGHT CLEARING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...CL/FRAZIER
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