550  
FXUS61 KPBZ 110019  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
819 PM EDT THU JUL 10 2025  
   
SYNOPSIS  
 
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS EXPECTED DAILY  
THROUGH THE WEEKEND WITH THE HIGHEST CHANCE ON SUNDAY AS A WEAK  
COLD FRONT CROSSES THE AREA. THE FIRST HALF OF NEXT WEEK MAY BE  
DRIER AHEAD OF ANOTHER LATE WEEK DISTURBANCE. TEMPERATURES WILL  
REMAIN A FEW DEGREES ABOVE NORMAL.  
 
 
   
NEAR TERM /THROUGH FRIDAY/  
 
KEY MESSAGES:  
 
- THE THREAT OF THUNDERSTORMS HAVE COME TO END THIS EVENING  
- ANOTHER NIGHT OF FOG POTENTIAL TONIGHT  
---------------------------------------------------------------  
 
EVENING UPDATE...THE DAYTIME HEATING HAS BEGUN TO WANE AND THE  
CAP IS SETTING IN FOR THE EVENING. THIS SHOULD CUT OFF ANY  
FURTHER THUNDERSTORM DEVELOPMENT THROUGH THE REST OF THE  
EVENING AND OVERNIGHT. THUS HAVE REMOVED POPS AFTER 01Z. A STRAY  
SHOWER IS STILL POSSIBLE BUT THE OVERALL THREAT IS LARGELY  
OVER. SOME AREAS OF FOG WILL BE POSSIBLE TONIGHT.  
 
PREVIOUS DISCUSSION...STUBBORN LOW STRATUS WILL GRADUALLY ERODE  
THIS MORNING BUT IS TAKING ITS TIME DOING SO. WHERE IT HAS  
CLEARED, TEMPERATURES HAVE RISEN RATHER QUICKLY WITH EFFICIENT  
SOLAR INSOLATION. THIS WILL SET THE STAGE FOR SCATTERED  
AFTERNOON AND EVENING SHOWERS AND STORMS.  
 
INITIATION SHOULD BE OFF OF THE LAKE BREEZE AS WELL AS A  
DIFFERENTIAL HEATING BOUNDARY IN EAST-CENTRAL OHIO ON THE CLEAR SIDE  
OF THE MORNING STRATUS AFTER 17Z. THE ENVIRONMENT TODAY WILL BE  
SUPPORTIVE OF HEAVY RAIN AND POSSIBLY DAMAGING WIND WITHIN ANY OF  
THE STRONGEST STORMS. CAMS SUGGEST UP TO 2000 J/KG MLCAPE WITH WEAK  
EFFECTIVE SHEAR AROUND 15-20 KNOTS. CORFIDI UPSHEAR VECTORS VALUES  
ARE LOW, BUT A BIT MORE THAN WE'VE HAD IN THE PAST COUPLE DAYS, ALSO  
AROUND 15-20 KNOTS WHICH SHOULD ALLOW FOR THE STRONGER STORMS TO BE  
A BIT MORE TRANSIENT. STILL, WITH OUR 12Z SOUNDING OF A 1.34 PWAT,  
WE'LL STILL HAVE SOME HEAVY RAIN PRODUCERS AND A LOCALIZED FLASH  
FLOODING THREAT IF ANY STORMS SIT OR TRAIN LONG ENOUGH OVER THE SAME  
AREA. THE DAMAGING WIND THREAT WILL BE FROM DOWNBURSTS, THOUGH  
THERE'S SOME QUESTION AS TO HOW VIGOROUS THE UPDRAFTS WILL BE ABLE  
TO GET. OUR SOUNDING AND MOST OF THE 12Z CAMS DEPICT 1) A WARM LAYER  
AROUND 700 MB THAT MAY ACT AS A CAP, AT LEAST UNTIL REPEATED  
UPDRAFTS COULD ERODE IT, AND 2) A LOT OF DRY AIR ABOVE 600 MB,  
POTENTIALLY ENOUGH TO INHIBIT DEVELOPMENT ABOVE IT. THIS MEANS THAT  
UPDRAFTS COULD LOOK STRONG IN THE LOWER LEVELS, UP TO AROUND  
FREEZING LEVEL TO -10C, BUT WITH NOT MUCH STRUCTURE ABOVE THERE AT  
LEAST UNTIL WET-BULBING WOULD OCCUR AND COULD GROW THE CAPE PROFILE  
A BIT. SO THE DOWNBURST THREAT WILL BE THERE CONTINGENT ON HIGHER  
UPDRAFT HEIGHTS OF WHICH WE'D BE LOOKING SOLID FOR 50 DBZ RETURNS TO  
REACH AROUND 19-20KFT.  
 
TIMING OF STORMS AT ANY GIVEN LOCATION WILL BE TOUGH TO PIN DOWN AS  
COLD POOL INTERACTION WILL DRIVE DOWNSTREAM DEVELOPMENT, BUT THE  
BEST WINDOW FOR OUR AREA WILL BE AFTER 12PM THROUGH SUNSET, STARTING  
TO THE NORTH AND WEST BEFORE MEANDERING FARTHER SOUTH.  
 
DRIER CONDITIONS TAKE HOLD TONIGHT BUT EXPECT THAT ANOTHER NIGHT OF  
FOG IS LIKELY GIVEN A STAGNANT AIRMASS AND PERSISTENCE. IT WILL BE  
AT ITS MOST DENSE IN AREAS THAT SEEN RAIN TODAY, BUT PLENTY OF NEAR-  
SURFACE MOISTURE, CALM WIND, AND SCATTERING CLOUDS WILL SUPPORT IT  
ACROSS A LOT OF THE AREA AND IT COULD BE DENSE IN SPOTS AGAIN. LOWS  
WILL BE MILD IN THE MID TO UPPER 60S.  
 
 
   
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/  
 
KEY MESSAGES:  
 
- SCATTERED AFTERNOON AND EVENING SHOWERS AND STORMS FRIDAY AND  
SATURDAY  
- HEAVY RAIN AND DAMAGING WIND THREAT WITH STRONGER STORMS  
----------------------------------------------------------------  
 
DIURNALLY DRIVEN CONVECTION WILL CONTINUE TO BE THE STORY ON FRIDAY  
AND SATURDAY WITH CONTINUED WEAK FLOW ALOFT, THOUGH SUBTLE MID-LEVEL  
HEIGHT RISES WILL OCCUR. ENSEMBLE MEAN PWAT VALUES REMAIN SIMILAR TO  
THURSDAY AROUND 1.3-1.5" WITH WEAK FLOW AND A 50-80% CHANCE OF  
SBCAPE VALUES >1500 J/KG EACH DAY. DCAPE VALUES SIT AROUND 800-1100  
ACROSS THE 12Z CAMS AGAIN SUPPORTIVE OF A VERY LOCALIZED HEAVY  
RAIN AND DOWNBURST THREAT. PEGGING DOWN EXACT TIMING AND  
LOCATION OF DEVELOPMENT AGAIN IS A FOOL'S ERRAND, ESPECIALLY  
WITH THE INFLUENCE OF REMNANT OUTFLOW BOUNDARIES FROM PREVIOUS  
DAYS. THERE ARE SUGGESTIONS THAT IT MAY BE MORE TERRAIN DRIVEN  
WITH HIGHER COVERAGE IN THE RIDGES AND TO THE EAST, BUT WOULD  
HAVE TO BELIEVE THAT REMNANT OUTFLOW AND THE LAKE BREEZE COULD  
AGAIN PLAY A ROLE.  
 
OUTSIDE OF CONVECTION, TEMPERATURES WILL CLIMB A BIT INTO THE  
UPPER 80S ON FRIDAY AND INCREASED PROBABILITY AS HIGH AS 90% IN  
THE URBAN AREAS AND VALLEYS (50-70% ELSEWHERE) TO REACH 90F  
SATURDAY.  
 
 
   
LONG TERM /SUNDAY THROUGH THURSDAY/  
 
KEY MESSAGES:  
 
- WETTER ON SUNDAY WITH A CROSSING BOUNDARY  
- POTENTIALLY DRIER FIRST HALF OF NEXT WEEK AHEAD OF ANOTHER  
LOW PRESSURE SYSTEM PASSAGE BY MID TO LATE WEEK  
- TEMPERATURES REMAIN ABOVE AVERAGE  
-------------------------------------------------------------------  
 
SUNDAY LOOKS TO BE THE WETTEST DAY OF THE WEEKEND AS LOW PRESSURE  
TRACKING ACROSS THE GREAT LAKES DRAGS A SURFACE COLD FRONT THROUGH  
THE AREA. THE BEST SHORTWAVE SUPPORT WILL TRACK NORTH OF LAKE ERIE,  
BUT THERE WILL BE A PLENTY WARM AND MOIST AIRMASS IN PLACE FOR THE  
BOUNDARY TO WORK UPON. CONFIDENCE IS HIGH THAT IT PASSES ON SUNDAY,  
BUT THE DETERMINISTIC GUIDANCE STILL SUGGESTS DIFFERENT TIMING WHICH  
WOULD IMPACT ANY SEVERE OR FLOODING THREAT. MACHINE LEARNING  
SUGGESTS THERE COULD BE A SEVERE THREAT, CONTINGENT ON AN AFTERNOON  
TO EVENING TIMING, BUT ORGANIZED SEVERE WEATHER SEEMS LESS LIKELY  
GIVEN STILL WEAK SHEAR AS THE STRONGEST FLOW REMAINS TO OUR NORTH.  
WILL CONTINUE MONITORING AS THE CAMS COME INTO PLAY.  
 
A MORE POTENT MID-LEVEL WAVE SWINGS THROUGH ON MONDAY IN BETTER  
AMPLIFIED FLOW AND COULD PROVIDE MORE AFTERNOON AND EVENING SHOWERS  
AND STORMS, THOUGH ENSEMBLES DEVIATE A BIT HERE WITH THE POST-  
FRONTAL ENVIRONMENT. SOME SUGGEST A SURFACE HIGH QUICKLY BUILDING IN  
THE WAKE OF THE FRONT WHILE OTHERS DON'T BRING THE HIGH IN QUITE  
THAT QUICKLY AND ALLOW FOR ANOTHER UNSETTLED DAY ON MONDAY. NBM  
STILL SUPPORTS 30-60% POPS, HIGHEST TO THE SOUTH AND EAST, BUT IT'S  
POSSIBLE THAT THAT COULD TREND DRIER IF THE MORE PROGRESSIVE  
SOLUTIONS PROVE CORRECT. NOT MUCH OF AN AIRMASS CHANGE IS LIKELY  
BEHIND THE FRONT, SO STILL EXPECTING ABOVE AVERAGE HIGHS ON MONDAY.  
 
TUESDAY AND WEDNESDAY SHOW INDICATIONS OF BEING DRIER ACROSS THE  
BOARD AS AFOREMENTIONED HIGH PRESSURE DOES SETTLE IN AND UPPER  
RIDGING BUILDS FROM THE SOUTHWEST. THIS WILL ALLOW TEMPERATURES  
TO CLIMB WITH WARM ADVECTION IN SOUTHWESTERLY FLOW BUMPING 90F  
PROBABILITY BACK UP TO 50-70% ON TUESDAY AND 60-80% ON  
WEDNESDAY, AGAIN HIGHEST IN THE URBAN AREAS. ENSEMBLES TRACK YET  
ANOTHER LOW PRESSURE SYSTEM OUT OF THE GREAT LAKES THURSDAY  
INTO FRIDAY WHICH WILL LIKELY BRING ANOTHER COLD FRONT THROUGH  
AND RETURN RAIN CHANCES. STILL SEEING A GOOD BIT OF DISAGREEMENT  
ON TIMING AND AMPLIFICATION OF THE RESPONSIBLE MID-LEVEL  
TROUGH, SO CONFIDENCE IS LOW THIS FAR OUT, BUT IT'S LESS LIKELY  
THAT WE KEEP THE DRY WEATHER AROUND THROUGH THE END OF THE WEEK.  
 
 
   
AVIATION /00Z FRIDAY THROUGH TUESDAY/  
 
THE LOSS OF DIURNAL HEATING AND SURFACE HIGH PRESSURE WILL  
DWINDLE LOW PROBABILITY SHOWERS AFTER SUNSET.  
 
A MOIST BOUNDARY LAYER COMBINED WITH CALM WIND AND CLEAR  
OVERNIGHT SKIES WILL FOSTER STRONG RADIATIONAL COOLING THAT  
RESULTS IN FOG BETWEEN 06Z-12Z. AN ANALYSIS OF THE PRIOR NIGHTS'  
FOG/STRATUS SHOWED THAT THE UPS FOG METHOD (FOCUSING ON DAYTIME  
MINIMUM DEW POINT AND THE TIME OVERNIGHT TEMPERATURES REACH THAT  
VALUE) PERFORMED WELL. GIVEN MINIMAL ENVIRONMENTAL CHANGES,  
TRENDED FORECAST BASED ON THIS FOG FORECAST METHOD WHICH  
RESULTED IN A LOWERING OF FOG POTENTIAL (BUT STILL PRESENT) AT  
MOST TERMINALS. THE BIGGEST VARIABLE CHANGE IS THE LACK OF RAIN  
TO REINFORCE SURFACE MOISTURE AND DIURNAL MIXING THAT INTRODUCED  
SOME DRIER AIR TO THE SURFACE.  
 
INSOLATION WILL BURN OFF ANY DEVELOPED IFR/LIFR FOG/STRATUS  
FRIDAY AND AID IN ISOLATED THUNDERSTORM DEVELOPMENT AFT 18Z.  
HI-RES MODELING IS BEARISH ON POTENTIAL, FAVORING LOCATIONS EAST  
OF I-77, SO ADDED PROB30 WORDING FOR THOSE TERMINALS.  
 
OUTLOOK...  
A WEAKLY FORCED BUT WARM/HUMID ENVIRONMENT IS FAVORED THROUGH  
SATURDAY THAT WILL ALLOW FOR INTERMITTENT PERIODS OF  
SHOWERS/THUNDERSTORMS. CONFIDENCE IS LIKELY TO BE LOWER ON  
TIMING VARIOUS ROUNDS OF PRECIPITATION AS WELL AS THE RESULTANT  
CIG/VSBY IMPACTS THEY COULD HAVE DURING THE MORNING HOURS.  
 
MORE SIGNIFICANT UPPER-LEVEL AND SURFACE BOUNDARY MOVEMENT  
APPEARS TO ARRIVE SUNDAY, WHICH WILL CREATE A BETTER FOCUSED  
PERIOD FOR CONVECTION AND RESTRICTION DEVELOPMENT.  
 
 
   
PBZ WATCHES/WARNINGS/ADVISORIES  
 
PA...NONE.  
OH...NONE.  
WV...NONE.  
 
 
 
 
 
SYNOPSIS...MLB  
NEAR TERM...MLB/SHALLENBERGER  
SHORT TERM...MLB  
LONG TERM...MLB  
AVIATION...FRAZIER  
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