635  
FXUS61 KPBZ 201156  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
656 AM EST THU FEB 20 2020  
   
SYNOPSIS
 
 
OUTSIDE OF ISOLATED FLURRIES TODAY, HIGH PRESSURE WILL MAINTAIN DRY  
CONDITIONS, WITH MODERATING TEMPERATURE THROUGH THE WEEKEND.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
MORNING UPDATE: NO MAJOR CHANGES HAVE BEEN MADE IN THIS FORECAST  
PERIOD.  
 
PREVIOUS DISCUSSION: DRY WEATHER, AS DEFINED BY NON- MEASURABLE  
PRECIPITATION, IS EXPECTED TO CONTINUE TODAY DESPITE THE ENCROACHMENT  
OF AN UPPER TROUGH/ASSOCIATED REINFORCING COLD FRONT. MODEL WORLD  
CONTINUES TO DISPUTE THE EVENTUAL MOISTURE SUPPLY AVAILABLE FOR  
PRECIPITATION OVER THE REGION WITH GFS REMAINING THE MORE AGGRESSIVE.  
EITHER WAY, SUFFICIENT LOW LEVEL LAPSE RATES INTO A SHALLOW  
DENDRITIC GROWTH, WITH FRONTAL LIFT AND FORCING FOR ASCENT VIA THE  
UPPER TROUGH, ALBEIT WEAK, ARE ENOUGH TO MAINTAIN A SLIGHT CHANCE OF  
SOME LIGHT SNOW/FLURRIES.  
 
EARLY TIMING OF THE REINFORCING COLD FRONT SHOULD HOLD HIGH  
TEMPERATURE ABOUT 10 DEGREES UNDER THE AVERAGES.  
 

 
   
SHORT TERM /FRIDAY THROUGH SUNDAY/
 
 
BROAD HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH SUNDAY WITH  
GRADUAL TEMPERATURE MODERATION. NO REAL CHANGE WAS MADE TO THE  
WEEKEND FORECAST.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
 
 
PRECIPITATION CHANCE IS FORECAST TO INCREASE AGAIN BY MONDAY AS  
SOUTHERN STREAM LOW PRESSURE EMERGES FROM THE PLAINS AND DIGS UP THE  
OHIO VALLEY AS IT WEAKENS. WITH COLDER AIR LOCKED NORTHWARD VIA THE  
NORTHERN STREAM OF THE JET, AND WITH WARM ADVECTION ON THE VAN OF THE  
LOW, PRECIPITATION WITH THAT EVENT SHOULD PRIMARILY BE RAIN.  
 
MODELS AGREE THAT AN AMPLIFYING, AND ENCROACHING UPPER TROUGH IS  
LIKELY TO CONTINUE PRECIPITATION CHANCES INTO MIDWEEK AND THEN BRING  
COLDER WEATHER TO THE REGION.  
 

 
   
AVIATION /12Z THURSDAY THROUGH MONDAY/
 
 
MARGINAL MVFR CIGS ARE POSSIBLE ACROSS FKL/DUJ LATER THIS MORNING  
AND EARLY AFTERNOON WITH A CROSSING SHORTWAVE. OTHERWISE, VFR IS  
EXPECTED THROUGH THE PERIOD WITH HIGH PRESSURE. ISOLATED FLURRIES  
ARE ALSO POSSIBLE TODAY WITH THE SHORTWAVE, BUT SHOULD REMAIN LIGHT  
ENOUGH SUCH THAT CONDITIONS REMAIN VFR.  
   
OUTLOOK
 
 
RESTRICTIONS WILL BE POSSIBLE LATE SUNDAY WITH THE APPROACH OF LOW  
PRESSURE.  
 

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

 
 

 
 
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