416  
FXUS61 KPBZ 210922  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
522 AM EDT SAT APR 21 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL PROVIDE DRY WEATHER AND A WARMING TREND  
TOWARDS SEASONABLE TEMPERATURES INTO EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
ONLY MINOR UPDATES TO SKY COVER AND HOURLY T/TD WERE NEEDED AT  
520 AM. FORECAST IS ON TRACK.  
 
PREVIOUS DISCUSSION...  
 
HIGH PRESSURE CENTERED OVER THE SOUTHERN GREAT LAKES WILL KEEP  
OUR QUIET WEATHER PATTERN GOING. TODAY WILL NOT BE AS CRYSTAL  
CLEAR AS FRIDAY THOUGH, AS CIRRUS AND EVENTUALLY MID CLOUD WILL  
SPILL OVER THE FLATTENING MISSISSIPPI VALLEY RIDGE, AIDED IN  
DEVELOPMENT BY SHALLOW NORTHEAST U.S. TROUGHING AND RRQ JET  
DYNAMICS. THE LOW LEVELS REMAIN MUCH DRIER, AND IN FACT LOWERED  
DEWPOINTS THIS AFTERNOON ON THE EXPECTATION OF DECENT MIXING.  
TEMPERATURES WILL WARM AS COMPARED TO YESTERDAY, BUT REMAIN  
SEVERAL DEGREES BELOW CLIMATOLOGICAL NORMS.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/
 
 
THE CLOUDS WILL LINGER THROUGH TONIGHT, KEEPING RADIATIONAL  
COOLING IN CHECK SOMEWHAT, AND THEN GET SHUNTED SOUTH SUNDAY AS  
THE SURFACE HIGH DRIFTS INTO OUR AREA. MEANWHILE, THE  
AFOREMENTIONED UPPER RIDGE WILL ONLY SLOWLY PUSH NORTHEASTWARD,  
FINALLY WORKING INTO OUR AREA BY MONDAY. AS THIS OCCURS, A  
PLAINS LOW WILL DRIFT INTO THE DEEP SOUTH BY MONDAY MORNING, AND  
THEN TURN NORTH TOWARDS THE TENNESSEE VALLEY DURING THE DAY.  
NORTHWARD PROGRESSION OF MOISTURE IS A BIT SLOWER THAN IN  
PREVIOUS RUNS, AND ELECTED TO REMOVE POPS FOR MONDAY, ALTHOUGH  
CLOUDS WILL BE ON THE INCREASE. TEMPERATURES WILL COMPLETE THEIR  
QUEST TO REACH SEASONAL LEVELS DURING THIS PERIOD.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
MODELS GENERALLY AGREE IN LIFTING THE UPPER LOW INTO THE OHIO  
VALLEY ON TUESDAY AND DEGENERATING IT INTO AN OPEN WAVE AS IT  
CROSSES THE APPALACHIANS ON WEDNESDAY. INCREASING MOISTURE AND  
ISENTROPIC LIFT WILL ALLOW FOR RAIN THROUGH THIS PERIOD.  
POPS/QPF ARE HIGHER IN THE RIDGES THAN IN AREAS TO THE WEST  
GIVEN THE TRACK OF THE SHORTWAVE.  
 
THE MODELS NO LONGER PHASE THIS FIRST WAVE WITH A FOLLOWUP  
NORTHERN STREAM DISTURBANCE, BUT THERE REMAINS DISAGREEMENT ON  
THE HANDLING OF THE NEXT COUPLE OF SHORTWAVES ROTATING THROUGH  
YET ANOTHER DEVELOPING LONGWAVE TROUGH. KEPT SOME FAIRLY GENERAL  
POPS IN THE FORECAST THROUGH THE WEEK. TEMPERATURES WILL  
GENERALLY REMAIN NEAR OR SEVERAL DEGREES BELOW CLIMATOLOGY.  
 

 
   
AVIATION /10Z SATURDAY THROUGH WEDNESDAY/
 
 
SFC HIGH PRESSURE SHOULD MAINTAIN VFR CONDITIONS THROUGH THE TAF  
PERIOD, THROUGH MID/HIGH CLOUDS SHOULD INCREASE UNDER WEAK UPPER  
TROUGHING.  
 
OUTLOOK...  
RESTRICTION POTENTIAL RETURNS WITH TUE/WED LOW PRESSURE.  
 

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

 
 

 
 
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