411  
FXUS61 KCTP 221431  
AFDCTP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE STATE COLLEGE PA  
1031 AM EDT FRI JUN 22 2018  
   
SYNOPSIS
 
 
A WARM FRONT WILL LIFT GRADUALLY LIFT ACROSS PENNSYLVANIA LATER  
TODAY THROUGH SATURDAY. DEEP AND MOIST SOUTHEASTERLY FLOW WILL  
FEED A LARGE AREA OF LIGHT TO MODERATE SHOWERS ACROSS MUCH THE  
COMMONWEALTH. THE NORTHEASTERN THIRD OF THE STATE STANDS THE  
BEST CHANCE OF REMAINING DRY TODAY AND INTO EARLY TONIGHT.  
 
UNSETTLED WEATHER WILL LAST THROUGH THE UPCOMING WEEKEND AS  
A BROAD UPPER LEVEL TROUGH EXTENDS FROM SOUTHEASTERN CANADA  
THROUGH THE MID ATLANTIC REGION.  
 
THE AFOREMENTIONED AREA OF LOW PRESSURE WILL TAKE A TRACK  
ACROSS THE EASTERN GREAT LAKES FRIDAY AND SATURDAY. THE COLD  
FRONT TRAILING SOUTH FROM THE LOW WILL PUSH THROUGH  
PENNSYLVANIA SUNDAY. INCREASINGLY HUMID AND OCCASIONALLY WET  
CONDITIONS ARE EXPECTED THROUGHOUT THE UPCOMING WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
MOIST SOUTHEAST FLOW IS TRANSPORTING ABUNDANT ATLANTIC MOISTURE  
INTO PA THIS MORNING. STEADIEST AND MOST PERSISTENT SHOWERS ARE  
MOVING NORTHWARD INTO THE SOUTH CENTRAL MOUNTAINS WHERE A 25 KT  
SE LLJ IS DIRECTED. THESE SHOWERS WILL CONTINUE TO SLOWLY DRIFT  
NORTHWARD ACROSS THE SW 2/3RDS OF CENTRAL PA THROUGH THIS  
AFTERNOON. AREAS WITH A LEAST AMOUNT OF SHOWER ACTIVITY WILL  
REMAIN MOSTLY CLOUDY AND COOL DUE TO EVAPORATIONAL COOING  
EFFECTS FROM AMBIENT LOW DEWPOINTS AND SHOWERS INTO THAT DRY  
AIR.  
 
CLOUD COVER, RAINFALL AND EASTERLY FLOW NORTH OF WARM FRONT WILL  
RESULT IN A COOL DAY FOR JUNE WITH READINGS LIKELY STUCK IN THE  
60S ACROSS THE CENTRAL MOUNTAINS AND ONLY REACHING THE LOW 70S  
OVER THE SUSQ VALLEY.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
 
 
WPC'S DAY2 SLGT RISK JUST BARELY TOUCHES THE FAR SOUTHERN  
BORDER COUNTIES. WILL HOLD OFF ON A FFA FOR NOW AND TRY TO  
PINPOINT WHEN AND WHERE HEAVIER CONVECTION WILL BE DEVELOPING -  
ESPECIALLY SATURDAY AND SUNDAY AS THE WARM FRONT LIFTS NORTH OF  
OUR AREA, AND NOTABLY HIGHER PWATS HELP TO INCREASE RAINFALL  
RATES FROM ANTICIPATED SCATTERED TO NUMEROUS TSRA.  
 
SREF'S PROBABILITY FOR CAPE EXCEEDING 1000 J/KG INCREASES TO  
ABOUT 40-50 PERCENT ACROSS THE NORTHEASTERN THIRD OF THE CWA,  
WHILE MUCH HIGHER CAPES AND THE RISK FOR STRONGER TSRA MOVES  
ACROSS SOUTHERN PA.  
 
FOR TODAY THROUGH SATURDAY, THE COMBINED EFFECT OF TODAY'S  
SHOWERY AND FAIRLY COOL CONDITIONS FOLLOWED BY INCREASING  
WARMTH, MOISTURE AND INSTABILITY WILL BRING ANYWHERE FROM LESS  
THAN 0.50 INCH ACROSS THE REGION NE OF KIPT TO BETWEEN 1.25 AND  
1.5 INCHES OVER THE SOUTHERN FEW LAYERS OF COUNTIES IN PA.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
 
 
MODELS SEEM TO HAVE A CONSENSUS AND THE CLOSED LOW SHOULD  
SLOWLY OPEN AS IT MOVES TO THE NORTHEAST. THEW WARM MOIST FLOW  
WITH ANOMALOUS PWATS WILL BRING LIFT THE WARM FRONT THROUGH  
SATURDAY, WITH A CLOUDY WET DAY IN STORE. THE LOW SHOULD OPEN TO  
A WEAK WAVE AND THE TRAILING COLD FRONT SHOULD MOVE THROUGH  
SUNDAY. THE GFS/EC DIFFER AT THIS POINT WITH THE GFS DEEPENING  
THE TROUGH AND COLDER UPPER LEVEL AIR. DRY AIR WILL FILTER INTO  
THE REGION EARLY NEXT WEEK WITH MILDER SUMMERLIKE WEATHER  
DOMINATING THE REGION THROUGH THE FIRST HALF OF NEXT WEEK.  
 

 
   
AVIATION /14Z FRIDAY THROUGH TUESDAY/
 
 
SHOWERS WILL SPREAD FROM SOUTHWEST TO NORTHEAST ACROSS THE  
AIRSPACE THROUGH TONIGHT. EXPECT CEILINGS TO STEADILY LOWER  
THROUGH FRIDAY AFTERNOON WITH HIGH CONFIDENCE IN WIDESPREAD  
MVFR AND IFR LIKELY TONIGHT INTO SATURDAY MORNING. LOOK FOR  
GRADUAL IMPROVEMENT IN CEILINGS FROM SOUTH TO NORTH THROUGH  
SATURDAY AFTERNOON WITH VARIABLE VISIBILITY IN LOCALLY HEAVY  
DOWNPOURS. THERE SHOULD BE A LULL IN PRECIP SATURDAY NIGHT WITH  
ADDITIONAL SHOWERS/STORMS LIKELY ON SUNDAY.  
   
OUTLOOK
 
 
 
MON...LOW CIGS PSBL N/W AIRSPACE EARLY, THEN IMPROVING.  
 
TUE...PATCHY VALLEY FOG IN THE MORNING, OTHERWISE VFR.  
 

 
   
CTP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
SYNOPSIS...DEVOIR/LAMBERT  
NEAR TERM...DEVOIR/LAMBERT  
SHORT TERM...FITZGERALD/LAMBERT  
LONG TERM...LAMBERT/CERU/STEINBUGL  
AVIATION...DEVOIR/STEINBUGL  
 
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