729  
FXUS61 KPBZ 181134  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
734 AM EDT THU SEP 18 2025  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL MAINTAIN WARM AND MOSTLY-DRY WEATHER INTO  
THE WEEKEND. RAIN CHANCES RETURN TO THE FORECAST NEXT WEEK,  
THOUGH THE CHANCE FOR WIDESPREAD WETTING RAIN REMAINS LOW.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
KEY MESSAGES:  
 
- AREAS OF FOG POSSIBLE EARLY THIS MORNING, ESPECIALLY IN  
VALLEYS  
- ABOVE-NORMAL TEMPERATURES CONTINUE  
---------------------------------------------------------------  
 
EASTERN-CONUS LOW PRESSURE WEAKENS INTO AN OPEN WAVE AS IT  
TRACKS INTO THE NORTHEASTERN CONUS TODAY. MOST OF ITS  
ASSOCIATED CLOUD COVER HAS DEPARTED, AND THE COMBINATION OF  
CLEAR SKY, LIGHT WIND, AND LINGERING SURFACE MOISTURE COULD  
SUPPORT SOME VALLEY FOG EARLY THIS MORNING. THE HREF CONTINUES  
TO SUPPORT THIS, SHOWING A MODERATE SIGNAL (40-50% PROBABILITY)  
OF BELOW 0.5 MI VISIBILITY FOR SOME LOCATIONS NORTH AND EAST OF  
PITTSBURGH, ESPECIALLY IN A CORRIDOR FROM CONNELLSVILLE TO  
DUBOIS PA, AND FROM FRANKLIN PA TO YOUNGSTOWN OH.  
 
WARM TEMPERATURES ARE FORECAST ACROSS THE BOARD THIS AFTERNOON  
WITH PLENTY OF SUN AND BUILDING HEIGHTS. EXPECT WIDESPREAD  
HIGHS ROUGHLY 10 DEGREES ABOVE NORMAL (LOWER AND MIDDLE 80S).  
 

 
   
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
 
 
KEY MESSAGES:  
 
- DRY WEATHER CONTINUES TO END THE WORK WEEK  
- A WEAK FRONT BRINGS COOLER TEMPERATURES NORTH OF US-422, WHILE  
AREAS FARTHER SOUTH REMAIN AROUND 10 DEGREES ABOVE NORMAL  
--------------------------------------------------------------  
 
AS THE NERN CONUS TROUGH CONTINUES TO DEPART TO THE EAST, A  
BLOCKING RIDGE CENTERED OVER THE LOWER MISSISSIPPI VALLEY AND  
WESTERN GREAT LAKES MAKES SLOW EASTWARD PROGRESS WITH TIME AND  
SETS UP SHOP OVER THE MIDDLE AND UPPER OHIO VALLEY BY FRIDAY. AT  
THE SURFACE, A WEAK BOUNDARY WILL LIKELY SETTLE INTO OUR REGION  
BEFORE STALLING OUT. A FEW MODEL SOLUTIONS ACTUALLY ATTEMPT TO SPIT  
OUT SOME LIGHT QPF WITH THIS FRONT FRIDAY/FRIDAY NIGHT, BUT THAT  
APPEARS UNLIKELY GIVEN THE MAGNITUDE OF DRY AIR CURRENTLY IN  
PLACE THAT WOULD NEED TO BE OVERCOME (VIA MOISTURE ADVECTION OR  
SUB-CLOUD EVAPORATION) AS WELL AS THE LACK OF SUFFICIENT  
SUPPORT/FORCING WITH INCREASING HEIGHTS. THE MOST RECENT NBM  
RUN CARRIES SUB-10 POPS FRIDAY AND FRIDAY NIGHT, WHICH SOUNDS  
FAR MORE REASONABLE. THUS, THE FORECAST CONTINUES THE EXTENDED  
RUN OF DRY WEATHER THROUGH FRIDAY NIGHT.  
 
HIGHS WILL BE A LITTLE MORE SUBDUED NORTH OF US-422 ON FRIDAY  
BEHIND THE FRONT, BACKING OFF TO THE UPPER 70S/AROUND 80, WHILE  
HIGHS TO THE SOUTH REMAIN AROUND 10 DEGREES ABOVE NORMAL.  
SIMILAR TRENDS WILL BE SEEN WITH OVERNIGHT LOWS, ALTHOUGH THEY  
WILL BE A BIT CLOSER TO CLIMATOLOGY.  
 

 
   
LONG TERM /SATURDAY THROUGH WEDNESDAY/
 
 
KEY MESSAGES:  
 
- STILL MOSTLY DRY AND WARMER THAN NORMAL THROUGH THE WEEKEND  
- SLIGHT UPTICK IN RAIN CHANCES NEXT WEEK  
- TEMPERATURES REMAIN ABOVE NORMAL MONDAY THROUGH WEDNESDAY,  
ALBEIT WITH A SLIGHT DOWNWARD TREND  
------------------------------------------------------------------  
 
DESPITE THE FRONTAL BOUNDARY WAVERING IN OUR REGION, A LARGELY  
DRY PATTERN IS FORECAST FOR SATURDAY AS THE UPPER RIDGE AXIS  
CROSSES, WITH HIGH TEMPERATURES SIMILAR TO FRIDAY. HOWEVER,  
THERE IS A BIT BETTER POTENTIAL FOR A LIGHT SHOWER OR TWO IN THE  
RIDGES SOUTHEAST OF PITTSBURGH, WITH BETTER INDICATIONS OF  
MOISTURE AND MODEST LOW-LEVEL CONVERGENCE. STILL, CHANCES OF A  
WETTING RAIN FROM THIS ACTIVITY REMAIN UNDER 15 PERCENT.  
 
ENSEMBLES/CLUSTER ANALYSIS CONTINUE TO SHOW A SLOWER TREND WITH  
THE PROGRESS OF THE NEXT UPSTREAM TROUGH, WITH THE AXIS  
PROGRESSING FROM THE UPPER MISSISSIPPI VALLEY ON SUNDAY TO JUST  
THE WESTERN/CENTRAL GREAT LAKES BY TUESDAY. SOME SOLUTIONS EVEN  
SUGGEST THE DEVELOPMENT OF A CUTOFF UPPER LOW SOMEWHERE OVER THE  
EASTERN PLAINS. THIS TREND, IN TURN, RESULTS IN JUST A SLOW  
INCREASE TO MINIMAL POPS, WITH SLIGHT CHANCE VALUES NORTHWEST OF  
PITTSBURGH SUNDAY NIGHT/MONDAY, BEFORE EVENTUALLY OVERSPREADING  
THE AREA TUESDAY/WEDNESDAY. QPF EXPECTATIONS ARE NOT HIGH. THE  
NBM SHOWS A 40-60 PERCENT CHANCE OF 0.10" OR MORE DURING THE  
72-HOUR PERIOD ENDING AT 12Z THURSDAY. WITH INCREASING RAINFALL  
DEFICITS, WE WILL NEED HEALTHIER PRECIPITATION TOTALS TO PUT A  
BETTER DENT IN THE DEVELOPING DROUGHT.  
 
OVERALL, ABOVE-NORMAL TEMPERATURES CONTINUE TO BE THE  
EXPECTATION THROUGH THE MIDDLE OF NEXT WEEK. STILL, WITH THE  
SLOWLY FALLING HEIGHTS AND INCREASING CLOUD COVER POTENTIAL, A  
MODEST DOWNWARD TREND IS THE MOST LIKELY SCENARIO. THE 25TH-75TH  
PERCENTILE SPREADS DO INCREASE THROUGH THIS PERIOD, INDICATING  
INCREASING UNCERTAINTY IN THE ULTIMATE VALUES. THIS IS  
REASONABLE GIVEN THE RANGE OF POTENTIAL SOLUTIONS REGARDING THE  
SPEED/POSITIONING OF THE UPSTREAM TROUGH.  
 

 
   
AVIATION /12Z THURSDAY THROUGH MONDAY/
 
 
VFR IS FAVORED THROUGH THE TAF PERIOD AS HIGH PRESSURE REMAINS  
IN CONTROL. MORNING VALLEY FOG, MOSTLY PREVALENT AT HLG, WILL  
ERODE BY 13Z AS MIXING ENSUES. CLOUD COVER WILL GENERALLY BE  
LIMITED TO FAIR WEATHER CUMULUS FOR THE BULK OF THE AFTERNOON,  
AND THESE CLOUDS WILL COLLAPSE WITH SUNSET. WEST-TO- NORTHWEST  
WIND WILL STAY NEAR OR LESS THAN 10 KNOTS.  
 
   
OUTLOOK.
 
 
VFR IS FAVORED UNDER THE INFLUENCE OF HIGH PRESSURE WITH  
LOCALIZED MORNING RIVER-VALLEY FOG THROUGH SAT. THE EXCEPTION  
IS INCREASING PROBABILITIES FOR A WEAK COLD FRONT SAGGING INTO  
NWRN PA FRI MORNING THAT MAY LEAD TO MVFR CIGS (30-50% LIKELIHOOD  
AT FKL/DUJ).  
 
APPROACH OF AN UPPER-LEVEL TROUGH MAY FOSTER LOW-PROBABILITY  
RAIN/SPRINKLES SUN/MON, FAVORING LOCATIONS NORTHWEST OF  
PITTSBURGH, BUT VFR IS LIKELY TO PERSIST.  
 

 
   
PBZ WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
OH...NONE.  
WV...NONE.  
 

 
 

 
 
SYNOPSIS...CERMAK/KRAMAR/CL  
NEAR TERM...CERMAK/KRAMAR/CL  
SHORT TERM...CERMAK/CL  
LONG TERM...CERMAK/CL  
AVIATION...RACKLEY/CL  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab OH Page
The Nexlab PA Page
The Nexlab WV Page
The Nexlab MD Page Main Text Page