187  
FXUS61 KPBZ 261915  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
315 PM EDT WED JUL 26 2017  
   
SYNOPSIS
 
 
SHOWERS AND THUNDERSTORMS RETURN THURSDAY AND FRIDAY AS A COLD  
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM MOVE THROUGH. DRY AND  
SEASONABLE WEATHER RETURNS THIS WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
DRY WEATHER IS EXPECTED TONIGHT, ALTHOUGH CLOUDS WILL INCREASE  
IN ADVANCE OF THE COLD FRONT MOVING INTO THE REGION. THE CLOUD  
COVER WILL KEEP TEMPERATURES ABOUT 5 DEGREES WARMER THAN LAST  
NIGHT'S VALUES.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/
 
 
SIMILAR TO PREVIOUS FORECAST, FORECAST CONFIDENCE FOR THIS  
PERIOD REMAINS LOW. THE ONE GENERAL CONCEPT THAT THE  
DETERMINISTIC MODELS AGREE ON IS THAT THE OVERALL RAIN SHIELD ON  
THURSDAY SHOULD BE SOMEWHAT FARTHER TO THE SOUTH. HAVE  
INCREASED THE GRADIENT IN POPS FROM NORTH TO SOUTH, PUSHING THE  
LINE OF LIKELY POPS FARTHER SOUTH AND KEEPING CHANCE POPS TO THE  
NORTH. HOWEVER, OVERALL PRECIPITATION ALONG THE COLD FRONT  
REMAINS SOMEWHAT UNORGANIZED. DUE TO CONCERNS ABOUT INSTABILITY,  
THE RISK OF CONVECTIVE WEATHER ON THURSDAY HAS BEEN LOWERED BY  
THE STORM PREDICTION CENTER DOWN TO A MARGINAL AREA ACROSS ALL  
COUNTIES. DAMAGING WINDS REMAIN THE PRIMARY THREAT.  
 
THERE SHOULD BE A BIT OF A LULL IN PRECIPITATION THURSDAY NIGHT  
AS THE SURFACE FRONT PLUNGES SOUTH, BUT PRECIPITATION WILL  
REDEVELOP AS AN UPPER LEVEL LOW DROPS INTO THE OHIO VALLEY ON  
FRIDAY AND HELPS TO RESTRENGTH LOW PRESSURE ALONG THE FRONT. ALL  
LOCATIONS HAVE LIKELY POPS ON FRIDAY. FORECAST MODELS CONTINUE  
TO SLOW DOWN THE DEPARTURE OF PRECIPITATION FRIDAY NIGHT INTO  
SATURDAY, AND HAVE DECIDED TO KEEP POPS IN THE FORECAST LONGER  
THROUGH THIS TIME PERIOD, WITH MORNING SHOWERS ON SATURDAY ONLY  
EXPECTED IN PITTSBURGH AND LOCATIONS EAST.  
 
WHILE THE SEVERE THREAT HAS DIMINISHED ON THURSDAY AND IS NOT  
PRESENT ON FRIDAY, FLOODING COULD STILL BE A POSSIBLE CONCERN.  
THE ENTIRE VERTICAL SOUNDING REMAINS QUITE MOIST, AND WARM CLOUD  
DEPTHS COULD SUPPORT PLENTY OF DOWNPOURS. IN ADDITION, FLOW WILL  
BE RATHER WEAK ON FRIDAY, MEANING THAT ANY STORMS THAT DO  
DEVELOP WILL BE SLOW MOVING IN NATURE. RAINFALL COULD RANGE  
ANYWHERE FROM A HALF INCH ALONG INTERSTATE 80 TO MORE THAN 2  
INCHES IN SOUTHERNMOST TUCKER COUNTY FROM THURSDAY MORNING  
THROUGH SATURDAY. HOWEVER, NO FLOOD WATCHES HAVE BEEN ISSUED AT  
THIS TIME BECAUSE OF THE EXTENDED TIME PERIOD OVER WHICH THE  
RAIN IS EXPECTED TO FALL.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
HIGH PRESSURE ACROSS THE GREAT LAKES SHOULD KEEP WEATHER DRY  
THROUGH THE EXTENDED FORECAST, WITH TEMPERATURES REMAINING  
SEASONABLE THROUGH THE PERIOD. A FRONT MAY APPROACH FROM THE  
NORTHWEST BY THE MIDDLE OF NEXT WEEK, BUT THE TIMING REMAINS  
HIGHLY UNCERTAIN.  
 

 
   
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
 
 
VFR CONDITIONS TODAY WITH LIGHT AND VARIABLE WINDS. A COUPLE OF  
HOURS EITHER SIDE OF SUNRISE, POSSIBILITY OF RESTRICTIONS OF  
3-5 MILES IN BR/HZ. BY LATER IN THE DAY THURSDAY, EXPECT CHANCE  
OF SCATTERED SHOWERS AND THUNDERSTORMS.  
   
OUTLOOK
 
 
RESTRICTION CHANCES RETURN THURSDAY NIGHT THROUGH FRIDAY AND  
POSSIBLY INTO SATURDAY AS LOW PRESSURE IMPACTS THE OHIO VALLEY.  
 

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

 
 

 
 
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