752  
FXUS61 KPBZ 211207  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
807 AM EDT MON OCT 21 2019  
   
SYNOPSIS
 
 
ONE MORE WARM AFTERNOON THEN A COLD FRONT BRINGS RAIN AND BREEZY  
WEATHER TONIGHT AND TUESDAY. NEAR AVERAGE TEMPERATURE WITH DRY  
WEATHER ARE EXPECTED THE REMAINDER OF THE WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
NO CHANGES TO THE ONGOING FORECAST OUTSIDE TWEAKING CURRENT  
TEMPERATURE TRENDS. PREVIOUS DISCUSSION BELOW...  
 
LIGHT WIND AND LIMITED CLOUD COVER OVERNIGHT HAS RESULTED IN PATCHY  
FOG DEVELOPMENT OVERNIGHT ACROSS THE REGION, IN ADDITION TO STEAM FOG  
ALONG AREA RIVERS. FOG WILL BEGIN TO LIFT/DISSIPATE MID-MORNING AS  
LOWER LEVELS BEGIN TO MIX. DRY CONDITIONS ARE EXPECTED TODAY WITH  
DAYTIME HIGHS 10-15 DEGREES ABOVE NORMAL, INCREASED SOUTHEASTERLY  
FLOW, AND INCREASING CLOUD COVERAGE AS A DEEPENING CLOSED UPPER LOW  
ADVANCES TOWARD THE UPPER MS VALLEY.  
 
LOW LEVELS WILL REMAIN MIXED TONIGHT AS THE ASSOCIATED FRONTAL  
BOUNDARY APPROACHES AND SFC PRESSURE GRADIENT INCREASES, RESULTING IN  
RELATIVELY MILD TEMPERATURES. LATEST GUIDANCE HAS TRENDED BACK ONSET  
OF PRECIPITATION AND DO NOT ANTICIPATE RAIN TO BEGIN ENTERING EASTERN  
OHIO ZONES UNTIL EARLY TUESDAY MORNING.  
 

 
   
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
 
 
RAIN COVERAGE WILL EXPAND FROM WEST TO EAST TUESDAY MORNING. STRONG  
FORCING FOR ASCENT OF PRECIPITABLE WATER IN EXCESS OF 1.40" (+ 90%  
CLIMATOLOGICAL AVERAGE) SHOULD SUPPORT PERIODS OF MODERATE RAINFALL  
THROUGH TUESDAY MORNING AS THE COLD FRONT QUICKLY ADVANCES THROUGH  
THE FORECAST AREA. IN GENERAL, EXPECT 0.5 AND 0.75" OF TOTAL  
PRECIPITATION WITH THE MAJORITY OF THAT OCCURING BETWEEN DAYBREAK AND  
NOON.  
 
DRY CONDITIONS WILL THEN RESUME AS HIGH PRESSURE QUICKLY BUILDS BACK  
IN BEHIND THE FRONT DURING THE AFTERNOON SUPPORT A DRYING TREND  
TUESDAY BEHIND THE COLD FRONT. GUSTY WINDS AND PERSISTENT CLOUD  
COVERAGE EXPECTED BEHIND THE FRONT WITH STRONG CAA. CLEARING IS  
OVERNIGHT, BUT GUSTY WINDS WILL CONTINUE THROUGH WEDNESDAY. LATEST  
GUIDANCE AGREES WELL WITH ANALOGS WHICH SUPPORT MAX GUSTS AROUND  
30KTS ACROSS THE REGION.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
MODEL CONSENSUS SUGGESTS RETURN FLOW AHEAD OF A DEEPENING PLAINS  
TROUGH WHICH SUPPORTS SEASONABLE TEMPERATURE IN THE LONG TERM.  
PRECIPITATION CHANCES WILL BE DICTATED BY SHORTWAVE ACTIVITY IN SWLY  
FLOW ALOFT AHEAD OF THE AFOREMENTIONED TROUGH. AT THIS TIME BEST  
CHANCES FOR PRECIPITATION LOOK TO BE LATER IN THE WEEKEND.  
 

 
   
AVIATION /12Z MONDAY THROUGH FRIDAY/
 
 
MEDIUM CONFIDENCE FORECAST AS SEVERAL SITES TEETER WITH RIVER VALLEY  
FOG. ANY FOG WILL DISSIPATE BY 14Z AS WIND WILL START TO PICK UP  
WITH SUSTAIN SPEEDS BETWEEN 10-14KTS AND GUSTS EXCEEDING 20KTS.  
HIGHEST SPEEDS WILL BE AT LBE AND HLG THIS AFTERNOON. VFR WEATHER CAN  
BE EXPECTED THE BALANCE OF THE DAY WITH SCATTERED TO BROKEN CIRRUS.  
AS A COLD FRONT GETS CLOSER CIGS AROUND 6-7KFT ARRIVE BY LATE  
AFTERNOON.  
 
LOW LEVEL WIND SHEAR WILL BE A CONCERN GIVEN STRONG WINDS JUST ABOVE  
THE GROUND OVERNIGHT. DID NOT INCLUDE IT IN THE TERMINALS YET,  
HOWEVER THE TIME WINDOW FOR THE GREATEST THREAT RESIDES BETWEEN 4Z-  
14Z.  
 
AS THE FRONT GETS CLOSER WIDESPREAD RAIN ARRIVES AFTER MIDNIGHT.  
RAIN WILL START AT ZZV AFTER 4Z THEN REACH WESTERN PA TERMINALS  
AROUND 9Z. THE TREND CONTINUES FOR A LATER ONSET OF RAIN AND WOULD  
NOT BE SURPRISED FOR A LATER TIME /1-3 HOURS/ THAN WHAT IS CURRENTLY  
FORECAST. EASTWARD PROGRESSION OF PRECIPITATION IS SLOW FROM OHIO TO  
PENNSYLVANIA SINCE THE LARGER TIME GAP IN ONSET TIME BETWEEN ZZV AND  
PIT THAN NORMAL.  
   
OUTLOOK
 
 
WIDESPREAD MVFR RESTRICTIONS ARE EXPECTED TUESDAY AFTERNOON AS THE  
COLD FRONT CROSSES. WIND GUSTS PERHAPS OVER 30KTS ARE POSSIBLE  
TUESDAY AFTERNOON THROUGH MUCH OF WEDNESDAY.  
 

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

 
 

 
   
AVIATION
 
98  
 
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