207  
FXUS61 KPBZ 291238  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
838 AM EDT SAT APR 29 2017  
   
SYNOPSIS
 
 
UNSETTLED BUT WARM WEATHER IS EXPECTED THROUGH THE WEEKEND.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
MID LEVEL SHORTWAVE IS CURRENTLY EXITING THE SOUTHEAST RIDGES  
WITH SHOWERS DIMINISHING WEST TO EAST MID MORNING. NEXT  
SHORTWAVE WITH MCS MOVING INTO SOUTHWEST OHIO WILL ARRIVE FOR  
THE AFTERNOON. HAVE ADJUSTED POPS TO TRY AND PLACE A SMALL  
WINDOW OF MAINLY DRY CONDITIONS MID MORNING INTO EARLY  
AFTERNOON, BUT TIMING WILL BE AN ISSUE. FOR NOW WITH LACK OF LOW  
LEVEL INSTABILITY AND FAST MOVEMENT OF APPROACHING WAVE, SEVERE  
OR FLASH FLOOD THREAT REMAINS LOW. NO CHANGES TO TEMPERATURES  
AT THIS TIME AS STILL EXPECT FRONT TO ATTEMPT TO SHIFT NORTH  
LATER TODAY.  
 
TONIGHT AS LAST SHORTWAVE EXITS DEVELOPING MID  
LEVEL RIDGE SHOULD BE ABLE TO SHUNT FRONT FARTHER NORTH,  
BRINGING WARMER AND MORE HUMID CONDITIONS, AND A LESSER CHANCE  
FOR SHOWERS.  
 

 
   
SHORT TERM /SUNDAY THROUGH MONDAY/
 
 
WARM FRONT WILL REMAIN NEAR THE NEW YORK BORDER THROUGH SUNDAY  
NIGHT AS HEIGHTS RISE ALOFT. THIS LOOKS TO KEEP A CAP ON  
WIDESPREAD ACTIVITY SUNDAY. WITH A MID LEVEL RIDGE ON SUNDAY  
MUCH WARMER AND MORE HUMID CONDITIONS WILL DEVELOP. RIDGE BEGINS  
TO BREAK DOWN MONDAY AS AN OCCLUDED STORM SYSTEM IN THE WESTERN  
GREAT LAKES PUSHES A COLD FRONT ACROSS THE REGION, WITH SHOWERS  
AND THUNDERSTORMS WITH FROPA.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
A CLOSED LOW WILL EVENTUALLY MOVE ACROSS SOUTHERN CANADA  
TUESDAY AND WEDNESDAY. THE SURFACE REFLECTION WILL MOVE DIRECTLY  
UNDER THE 500 LOW, KEEPING THE CHANCE FOR SHOWERS IN THE  
FORECAST. A COOLER AND UNSETTLED PATTERN WILL CONTINUE INTO  
LATE WEEK AS A MEAN MID LEVEL TROUGH REMAINS ACROSS THE ERN  
CONUS.  
 

 
   
AVIATION /13Z SATURDAY THROUGH WEDNESDAY/
 
 
IMMEDIATE CONCERN AT THE BEGINNING OF THE 12Z TAF PERIOD IS LOW  
LEVEL WIND SHEAR, WITH RELATIVELY LIGHT SURFACE WINDS AROUND A  
WARM FRONT AND STRONG WESTERLY WINDS ALOFT. LATEST COMPUTER  
MODELS SUGGEST LLWS SHOULD HAVE ALREADY COME TO AN END, ALTHOUGH  
OBSERVATIONS INCLUDING VAD WIND PROFILE AND UPPER AIR BALLOON  
SHOW THESE WINDS ARE STILL PRESENT. WITH MODELS NOT MUCH HELP IN  
THIS CASE, HAVE INCLUDED LLWS IN TAFS OTHER THAN FKL/DUJ THROUGH  
15Z, AND WILL REEVALUATE SITUATION WITH LATER OBSERVATIONS.  
 
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE EASTWARD ALONG A  
SLOWLY NORTHWARD MOVING WARM FRONT TODAY. THIS WILL MEAN THEY  
WILL START THE DAY MAINLY FROM KPIT SOUTHWARD, THEN GRADUALLY  
TRANSITION NORTHWARD TOWARD KFKL/KDUJ AFTER A GAP THROUGH MUCH  
OF THE MORNING. A FAIRLY POTENT WAVE SHOULD TRANSITION DOWN THE  
FRONT EARLY IN THE AFTERNOON, WHICH WILL LIKELY ALLOW FOR THE  
BEST CHANCE OF THUNDERSTORMS AS IT PASSES MOST SITES DURING THIS  
INTERLUDE. AS THE WARM FRONT LIFTS NORTH OF THE AREA SATURDAY  
EVENING, MOST SITES WILL SCATTER OUT, HOWEVER SOME STRATUS MAY  
LINGER AROUND KFKL/KDUJ.  
   
OUTLOOK
 
 
RESTRICTIONS ARE POSSIBLE THROUGH SUN IN VICINITY OF A SURFACE  
FRONT. RESTRICTION ARE LIKELY WITH A STRONG COLD FRONT SUNDAY  
NIGHT AND MONDAY.  
 

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

 
 

 
 
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