425  
FXUS61 KCTP 250324  
AFDCTP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE STATE COLLEGE PA  
1124 PM EDT SUN MAY 24 2020  
   
SYNOPSIS
 
 
AN ANOMALOUS UPPER LEVEL RIDGE WILL BUILD OVER PENNSYLVANIA  
THROUGH THE MIDDLE OF NEXT WEEK. A WEAK AREA OF LOW PRESSURE  
APPROACHING FROM THE CAROLINAS IS LIKELY TO LIFT NORTH INTO THE  
AREA NEXT THURSDAY, FOLLOWED BY A COLD FRONT SWEEPING IN FROM  
THE GRT LKS AT THE END OF THE WEEK. HIGH PRESSURE IS LIKELY TO  
BUILD INTO PENNSYLVANIA BY NEXT WEEKEND.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
LATE EVENING SATELLITE IMAGERY SHOWS STRATUS FILLING AND  
EXPANDING ACROSS CENTRAL PA DUE TO NOCTURNAL COOLING AND  
CONTINUED MOIST SOUTHEAST FLOW OFF OF THE ATLANTIC. MOISTURE  
LOOKS DEEP ENOUGH IN MODEL SOUNDINGS TO SUPPORT A BIT OF DRIZZLE  
OVERNIGHT ALONG THE SPINE OF THE APPALACHIANS FROM SOMERSET/BEDFORD  
COUNTIES NORTHEAST TO SULLIVAN COUNTY. HOWEVER, THE LARGE MAJORITY  
OF THE REGION SHOULD REMAIN DRY OVERNIGHT UNDER BUILDING UPPER  
LEVEL RIDGE.  
 
SCATTERED CONVECTION IS NOTED UPSTREAM OVER SOUTHERN ONTARIO  
THIS EVENING. THE SHORTWAVE ASSOCIATED WITH THIS CONVECTION IS  
PROGGED TO PASS WELL NORTH OF PA. HOWEVER, THE TRAILING LOW  
LEVEL JET AND PLUME OF HIGHER PWATS WILL SAG INTO WESTERN NY  
BY DAWN. THEREFORE, WILL MAINTAIN JUST A CHANCE OF A SHOWER  
TOWARD DAWN OVER THE NORTHERN TIER COUNTIES. CLOUD COVER,  
FAIRLY HIGH DEWPOINTS AND A SOUTHEAST BREEZE WILL KEEP TEMPERATURES  
FROM FALLING MUCH TONIGHT. EXPECT READINGS IN THE 50S AT DAWN.  
 
MODEL RH PROFILES INDICATE MONDAY SHOULD DAWN CLOUDY OVER MOST  
AREAS EAST OF THE APPALACHIANS. HOWEVER, THE LOW LEVEL FLOW IS  
PROGGED TO WEAKEN AND VEER FROM SOUTHEAST TO SOUTH-SOUTHEAST,  
SO EXPECT A BRIGHTER AFTERNOON OVER THE EASTERN HALF OF THE  
STATE THAN TODAY.  
 
THE VAST MAJORITY OF CENTRAL PA SHOULD SEE RAIN-FREE CONDITIONS  
ON MEMORIAL DAY DUE TO LINGERING SURFACE RIDGE AND STABLE  
MARITIME AIR MASS OVER THE SOUTHEAST HALF OF THE STATE. HOWEVER,  
GREATER INSTABILITY ASSOCIATED WITH A WEAK WARM FRONT MOVING  
INTO NORTHERN AND WESTERN PA WILL LIKELY RESULT IN SCATTERED,  
PULSE-TYPE CONVECTION DURING THE AFTERNOON ACROSS NORTHERN  
MOUNTAINS. WARMER TEMPS ALOFT SHOULD CAP CONVECTION OVER THE  
LAUREL HIGHLANDS.  
 
THE WARMEST TEMPERATURES ON MEMORIAL DAY SHOULD BE ACROSS THE  
NORTHWEST MOUNTAINS, WHERE AFTERNOON READINGS AROUND 80F ARE  
LIKELY. MORE CLOUD COVER AND FLOW OFF OF THE ATLANTIC SHOULD  
TEMPER THE WARM UP FURTHER EAST WITH HIGHS IN THE MID TO UPPER  
70S.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
 
 
ANY CONVECTION SHOULD FADE INTO MONDAY NIGHT, WITH PARTLY  
CLOUDY TO MOSTLY CLEAR SKIES FOR THE OVERNIGHT PERIOD. SOME  
PATCHY VALLEY FOG IS POSSIBLE INTO EARLY TUESDAY MORNING GIVEN  
NEARLY CALM WINDS AND DEWPOINTS IN THE LOW 60S.  
 
A STRETCH OF SUMMER-LIKE WEATHER IS EXPECTED NEXT WEEK COURTESY  
OF ANOMALOUS UPPER LEVEL RIDGING OVER THE MID ATLANTIC REGION.  
HIGH CONFIDENCE IN ABOVE AVERAGE TEMPERATURES AND MOSTLY RAIN-  
FREE CONDITIONS. FORECAST HIGH TEMPERATURE DEPARTURES FROM  
NORMAL SHOULD RUN +5 TO +15 DEGREES, BUT DAILY MAXES ARE NOT  
EXPECTED TO REACH RECORD TERRITORY. THE RUN OF MAINLY DRY  
WEATHER INTO MONTH-END WILL INCREASE THE ODDS FOR A POTENTIAL  
TOP-10 DRIEST MAY AT SITES SUCH AS KMDT, KAOO, KIPT, AND STCP1.  
 
THE BEST CHANCE OF ISOLATED DIURNAL CONVECTION THROUGH MIDWEEK  
WILL BE OVER THE ELEVATED HEAT SOURCE OF THE ALLEGHENY PLATEAU.  
 

 
   
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
 
 
MED RANGE GUIDANCE IS IN RELATIVELY GOOD AGREEMENT THROUGH LATE  
NEXT WEEK, ALL OF WHICH TRACK THE REMNANTS OF WEAK SURFACE LOW  
OFF OF THE SOUTHEAST COAST NORTHWARD INTO PA ALONG WESTERN  
PERIPHERY OF RETREATING UPPER RIDGE. BASED ON AGREEMENT AMONG  
LATEST GEFS AND OPERATIONAL RUNS, HAVE INCREASED POPS THURSDAY.  
HAVE ALSO LOWERED TEMPERATURES THURSDAY DUE TO EXPECTED CLOUD  
COVER AND EASTERLY FLOW.  
 
THE LATEST ECENS AND NAEFS BOTH TRACK A POTENT COLD FRONT  
SOUTHEAST ACROSS PA FRIDAY PM, LIKELY ACCOMPANIED BY A ROUND OF  
SHOWERS AND THUNDERSTORMS. THERE ARE SOME MODEL DIFFERENCES  
WITH RESPECT TO HOW FAST THE FRONT CLEARS SOUTHEAST PA EARLY  
SATURDAY. HOWEVER, THE BULK OF GUIDANCE SUPPORTS A RETURN TO FAIR  
AND SEASONABLE WEATHER NEXT WEEKEND, AS HIGH PRESSURE BUILDS IN  
FROM THE GRT LKS.  
 

 
   
AVIATION /04Z MONDAY THROUGH FRIDAY/
 
 
WIDESPREAD STRATUS PERSISTS OVER THE AREA THIS EVENING AND WILL  
CONTINUE TO LOWER OVERNIGHT, WITH MVFR CIGS LOWERING TO IFR FOR  
MOST SITES. WINDS WILL BE S-SE AT 5-10 KT, WITH SOME GUSTS 15-20  
KT OVER THE HIGHER TERRAIN BEFORE 06Z.  
 
MORNING STRATUS WILL GIVE WAY TO SCATTERED AFTERNOON CU ACROSS  
THE AREA ON MON. A FEW SHRA/TSRA WILL LIKELY DEVELOP NEAR LAKE  
ERIE MON AFTERNOON, WITH SCATTERED TSRA POSSIBLE IN THE NORTHERN  
ALLEGHENIES MAINLY AFTER 18Z.  
 
OUTLOOK...  
 
TUE...LOW CIGS POSSIBLE IN AM; MAINLY VFR.  
 
WED...ISOLATED TSRA  
 
THU...TSRA LIKELY AFTEROON  
 
FRI...RA/TSRA LIKELY WITH COLD FRONT  
 

 
   
CTP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
SYNOPSIS...FITZGERALD  
NEAR TERM...FITZGERALD  
SHORT TERM...STEINBUGL/COLBERT  
LONG TERM...FITZGERALD  
AVIATION...COLBERT  
 
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