909  
FXUS61 KPBZ 251316  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
916 AM EDT SAT MAR 25 2017  
   
SYNOPSIS
 
 
WELL ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK.  
A FEW ISOLATED SHOWERS ARE POSSIBLE TODAY BUT MORE WIDESPREAD  
PRECIPITATION IS EXPECTED LATER SUNDAY AFTERNOON AND EVENING.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
WITH 915AM UPDATE, PRIMARY UPDATE WAS TO INCREASE HIGH  
TEMPERATURES BY A COUPLE OF DEGREES TODAY. IT'S STILL QUITE  
EARLY IN THE DIURNAL CYCLE TO DETERMINE WHAT TEMPERATURE TRENDS  
WILL BE FOR TODAY, BUT YESTERDAY THE HIGH-RESOLUTION MODELS DID  
A MUCH BETTER JOB HANDLING THE WELL ABOVE NORMAL TEMPS, AND SO  
HAVE DECIDED TO TWEAK THE TEMPERATURES IN THAT DIRECTION. LATEST  
RUNS OF THE HRRR/RAP HAVE FORECASTS VERY SIMILAR TO YESTERDAY'S  
OBSERVED HIGHS. WHILE TEMPERATURES THIS MORNING STARTED MUCH  
WARMER THAN THEY DID YESTERDAY, MORE CLOUD COVER IS EXPECTED  
TODAY AS WELL. ALSO SLOWED UP THE CHANCE OF SHOWERS ACROSS  
NORTHERN COUNTIES CONSIDERING CURRENT RADAR/OBSERVATIONS HAVE  
RAIN FARTHER NORTH THAN DEPICTED IN SYNOPTIC MODELS. WILL WAIT  
UNTIL THE NOON UPDATE TO DETERMINE WHETHER POPS CAN EVENTUALLY  
BE REDUCED/ELIMINATED FOR THE AFTERNOON HOURS. PREVIOUS  
DISCUSSION FOLLOWS.  
 
CLOUD COVER AND ONGOING WARM ADVECTION SUPPORTED A VERY WARM  
NIGHT WITH TEMPERATURES 25 TO 30 DEGREES ABOVE THE AVERAGES.  
MORNING HOURLY TRENDS WERE TWEAKED TOWARD THE MUCH WARMER NAM  
AND HIGH RES MODELS IN CONJUNCTION WITH CURRENT OBSERVATIONS.  
 
OTHERWISE, SHORTWAVE RIDGING ON THE VAN OF A CUTOFF PLAINS LOW  
SUPPRESSES WILL SUPPRESS WIDESPREAD PRECIP FOR MOST OF THE  
REGION. THE EXCEPTION MAY BE THE I 80 CORRIDOR WHERE THE  
ENCROACHMENT OF A FRONT IN CONJUNCTION WITH A NORTHERN STREAM  
SHORTWAVE MAY SUPPORT SOME ISOLATED, TO SCATTERED SHOWERS TODAY.  
 
WITH THE UPPER OHIO FIRMLY ENTRENCHED UNDER THE RIDGE/WARM SECTOR,  
WARM HIGH-TEMPERATURES CAN AGAIN BE EXPECTED WITH READINGS  
ABOUT 20 DEGREES ABOVE THE AVERAGES FORECAST, WITH ONLY MINOR  
MODERATION PROJECTED ALONG THE I 80 COUNTIES AS THE  
AFOREMENTIONED FRONT SAGS TOWARD/ACROSS THAT AREA.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/
 
 
AS THE CUTOFF LOW OVER THE PLAINS DIGS EASTWARD THIS WEEKEND,  
SHORTWAVE RIDGING WILL SUPPRESS WIDESPREAD RAIN AND MAINTAIN  
WARMTH FOR THE IMMEDIATE AREA. MOIST FLOW AND THAT SYSTEMS  
OCCLUDED FRONT WILL DEGRADE THAT INHIBITION ON SUNDAY AND POPS  
WILL BE ON THE INCREASE, ALBEIT WITH QUESTIONABLE TIMING GIVEN  
MODEL DISCREPANCY IN HANDLING THE CUTOFF LOW.  
 
FOR NOW, HAVE CONTINUED THE ONGOING CATEGORICAL POPS, BUT HAVE  
ADJUSTED TIMING AND THE MENTION OF THUNDER GIVEN INSTABILITY  
PROJECTIONS. RENEWED SHORTWAVE RIDGING IN THE WAKE OF THAT  
WEAKENING SYSTEM, AND IN ADVANCE OF ANOTHER MIDWESTERN SHORTWAVE  
IN TIMED TO PROVIDE A BREAK IN PRECIP FOR MONDAY.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
ZONAL AND SPLIT FLOW IS FORECAST TO INITIALLY MAINTAIN ABOVE  
AVERAGE TEMPERATURE FOR THE REMAINDER OF THE WEEK, ALTHOUGH A  
MIDWEEK FRONT IS EXPECTED TO DROP THEM CLOSER TO THE AVERAGES.  
 
THE NEXT, BEST CHANCE FOR PRECIP IS EXPECTED WITH THAT FRONT  
AND WITH ANOTHER, ALBEIT FILLING CUTOFF LOW EMERGING FROM THE  
PLAINS BY THE WEEKEND. TWEAKED SUPERBLEND WAS USED IN LONG-TERM  
FORECAST CONSTRUCTION.  
 

 
   
AVIATION /13Z SATURDAY THROUGH WEDNESDAY/
 
 
VFR CONDITIONS ARE EXPECTED TODAY. WINDS WILL VEER OVER THE  
COURSE OF THE DAY AS A FRONT SLOWLY TRANSITIONS SOUTH OVER THE  
REGION, HOWEVER, VFR LEVELS SHOULD BE MAINTAINED.  
 
OUTLOOK...  
WIDESPREAD RESTRICTIONS ARE LIKELY ON SUNDAY WITH CROSSING LOW  
PRESSURE, AND AGAIN WITH A MONDAY NIGHT COLD FRONT.  
 

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

 
 

 
 
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