647  
FXUS61 KPHI 260642  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
242 AM EDT THU MAY 26 2016  
   
SYNOPSIS
 
 
OUR AREA WILL REMAIN ON THE WESTERN PERIPHERY OF AN AREA OF HIGH  
PRESSURE LOCATED OVER THE OCEAN OFF THE EAST COAST THROUGH THE END  
OF THIS WEEK INTO THE WEEKEND. A BACKDOOR COLD FRONT MAY APPROACH  
THE AREA FROM THE NORTH THIS WEEKEND, BUT SHOULD END UP REMAINING  
TO OUR NORTH. AN AREA OF LOW PRESSURE MOVING INTO NEW ENGLAND EARLY  
NEXT WEEK IS FORECAST TO BRING A COLD FRONT ACROSS OUR AREA AROUND  
TUESDAY.  
 

 
   
NEAR TERM /THROUGH TODAY/
 
 
PRIOR TO SUNRISE. FAIR (VARIABLE CIRRUS). LIGHT SOUTHWEST OR CALM  
WIND.  
 
AFTER SUNRISE...A SECOND MOSTLY SUNNY VERY WARM DAY IS AHEAD WITH  
A FEW LOCATIONS IN OUR FORECAST AREA LIKELY NUDGING 90F FOR THE  
FIRST TIME THIS YEAR INCLUDING KABE, KRDG, KPNE, KSMQ, KGED BUT  
MAINLY NORTHWARD FROM NEAR PHL ALONG AND WEST OF THE NJT TO KABE  
AND KRDG. WIND THIS AFTERNOON SOUTH TO SOUTHWEST GUSTING TO 15 MPH.  
A MIDDAY OCEAN INFLUENCED SOUTH SOUTHEAST SEA BREEZE WILL EVENTUALLY  
LOWER THE NEAR 80F LATE MORNING MAX TEMPS SIGNIFICANTLY BY MID  
AFTERNOON. OTHERWISE, HIGH TEMPS IN THE INTERIOR AROUND 10-13F DEGREES  
ABOVE NORMAL. POPS WITHDRAWN FROM E PA LATE TODAY AND IT APPEARS ANY  
SHOWERS SHOULD DEVELOP AFTER 6 PM THERE, IF AT ALL. NOT MUCH LIFT  
MECHANISM DESPITE WEAK INSTABILITY BURST.  
 
FCST BASIS: GENERALLY A 50 50 BLEND OF THE 00Z/26 GFS/NAM MOS  
GUIDANCE. HAVE CHECKED ALL 00Z/26 MAX TEMPS TOOLS FROM MET/MAV,  
BIAS ADJUST OF THESE AS WELL AS NATIONAL AND SUPER BLEND AND BASICALLY  
RAISED THE HIGHEST OF THE WARMEST GUIDANCE AWAY FROM THE BAYS AND  
ATLANTIC COASTS BY 1-2F. THAT MEANS THE 89 AT KPHL, 84 KMPO, 90 AT  
KABE AND KGED AS WELL AS 89 AT KFWN ARE ALL ALL FCST ABOVE THE WARMEST  
GUIDANCE...IN PART DUE TO THE INITIAL WESTERLY ISOBARIC FLOW.  
 

 
   
SHORT TERM /TONIGHT/
 
 
TONIGHT...A SMALL CHANCE OF A SHOWER OR MAYBE EVEN AN ISOLATED  
THUNDERSTORM ADVANCING EASTWARD INTO OUR FORECAST AREA...TOWARD  
MIDNIGHT, MAINLY EASTERN PA AND E MD. GUIDANCE LOWERED TOWARD THE  
DRIER MET/ECMWF/UKMET GUIDANCE. AM NOT EXPECTING MUCH AND MY  
CONFIDENCE ON ANY RAIN OCCURRENCE TONIGHT IS BELOW AVERAGE.  
(00Z/26 SPC WRF N/A BUT NSSL WRF WAS QUICKLY REVIEWED).  
 
A MILDER NIGHT THAN WHAT IS OCCURRING EARLY THIS THURSDAY MORNING.  
MIN TEMPS AROUND 10-13 DEGREES ABOVE NORMAL.  
 
FCST BASIS WAS A 50 50 BLEND OF 00Z/26 GFS/NAM GUIDANCE EXCEPT  
FAVORED THE DRIER 00Z/NAM MET POP GUIDANCE.  
 

 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/
 
 
A SUMMER LIKE PATTERN CONTINUING WITH A WARM, ABOVE NORMAL PERIOD  
AHEAD FOR OUR AREA FOR THE END OF THE WEEK, THROUGH THE WEEKEND,  
AND INTO EARLY NEXT WEEK. ALSO, CHANCES OF SHOWERS AND  
THUNDERSTORMS BASICALLY EACH DAY.  
 
HIGH PRESSURE WILL REMAIN TO OUR EAST WELL OFFSHORE THROUGH THE  
END OF THE WEEK INTO THE WEEKEND, WITH OUR AREA ON THE  
WESTERN PERIPHERY. THIS WILL KEEP A SOUTHERLY FLOW ACROSS THE  
AREA. MEANWHILE, RIDGING ALOFT BEGINS TO TAKE PLACE AS WELL. IN  
TURN, THICKNESSES WILL RISE INTO THE WEEKEND, HELPING  
TEMPERATURES RISE WELL ABOVE NORMAL. FRIDAY, SATURDAY, AND SUNDAY  
LOOK TO BE THE WARMEST DAYS OF THE UPCOMING FORECAST PERIOD. BY  
MONDAY, THE RIDGE ALOFT BREAKS DOWN SOME, SO THE TEMPERATURES MAY  
COOL DOWN A COUPLE OF DEGREES. HOWEVER, THE RIDGING MAY RETURN FOR  
TUESDAY INTO WEDNESDAY WHICH WOULD ALLOW TEMPERATURES TO RISE A  
FEW MORE DEGREES.  
 
THERE WILL BE A CHANCE OF ISOLATED TO SCATTERED SHOWERS EACH  
DAY, ESPECIALLY DURING THE DAY WITH AFTERNOON HEATING. THE BEST  
CHANCE OF SHOWER/THUNDERSTORM ACTIVITY WILL BE TIED TO INDIVIDUAL  
VORTICITY, SHORT WAVE IMPULSES.  
 
A BACKDOOR COLD FRONT MAY APPROACH THE AREA OVER THE WEEKEND,  
BUT SHOULD STAY NORTH OF THE AREA. IF IT DOES MAKE ITS WAY INTO  
OUR NORTHERN AREAS, IT COULD HOLD TEMPERATURES DOWN ON THE  
NORTHERN SIDE, AND POSSIBLY BRING A HIGHER SHOWER POTENTIAL. BUT  
FOR NOW, WE DO NOT EXPECT IT TO MAKE ITS WAY INTO OUR AREA.  
 
THERE IS SOME TIMING DIFFERENCES WITH THE NEXT ACTUAL FRONTAL  
PASSAGE, WITH THE GFS BRINGING THE FRONT THROUGH ON TUESDAY, AND  
THE ECMWF BRINGING THE FRONT THROUGH ON MONDAY. WE'LL KEEP CLOSER  
TO THE GFS AND AND WPC WITH A LATE TUESDAY PASSAGE. EITHER WAY,  
THERE WILL STILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS BOTH  
DAYS.  
 

 
   
AVIATION /07Z THURSDAY THROUGH MONDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,  
KMIV, KACY AND SURROUNDING AREAS.  
 
THROUGH 12Z...VFR WITH VARIABLE CIRRUS. SMALL CHANCE OF ISOLATED  
MVFR VSBY NEAR 10Z VCNTY KRDG OR KMIV BUT DEWPOINTS ARE SO LOW  
THAT FOG IS UNLIKELY. LIGHT SOUTH TO SOUTHWEST WIND.  
 
AFTER 12Z TODAY...VFR. SCT CLOUDS AOA 6000 FT, MAINLY THIS  
AFTERNOON. SOUTH TO SOUTHWEST WIND SHOULD GUST 15 KT THIS  
AFTERNOON.  
 
TONIGHT...VFR SCT-BKN AOA 6000 FT. SMALL CHANCE OF A SHOWER OR  
ISOLATED TSTM NEAR 06Z/27...MAINLY KRDG, KABE AFTER 03Z/27.  
 
OUTLOOK...  
 
FRIDAY-MONDAY...GENERALLY VFR DURING THE DAY THROUGH THE PERIOD.  
A CHANCE OF SHOWERS AND THUNDERSTORMS, MOSTLY DURING THE DAY,  
WHICH MAY TEMPORARILY LEAD TO LOWER CONDITIONS. SOME FOG  
DEVELOPMENT OVERNIGHT INTO THE MORNING EACH DAY.  
 

 
   
MARINE
 
 
NO MARINE HEADLINES ANTICIPATED THROUGH TONIGHT.  
 
SOUTHWEST WINDS WITH SCATTERED GUSTS 15 KT THIS MORNING BECOME  
SOUTH TO SOUTHEAST THIS AFTERNOON, ALSO WITH GUSTS TO 15 KT...THEN  
RETURN TO SOUTHWEST OVERNIGHT-THIS COMING THURSDAY NIGHT.  
 
SEAS AOB 3 FEET. USED THE LATEST AVAILABLE MORE CONSERVATIVE NWPS  
GUIDANCE (25/18Z RUN).  
 
OUTLOOK...  
 
FRIDAY-MONDAY...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED.  
WINDS MAY GUST NEAR 20 KNOTS, ESPECIALLY THURSDAY NIGHT THROUGH  
FRIDAY NIGHT.  
 

 
   
CLIMATE
 
 
THE PHILADELPHIA MONTHLY AVERAGE TEMPERATURE CONTINUES TO PROJECT  
ONLY ABOUT 1F BELOW NORMAL... WITH THIS CURRENT END OF THE MONTH  
STRETCH OF ABOVE NORMAL TEMPERATURES DENTING THE FIRST 24 DAYS,  
NEARLY 4 DEGREE BELOW AVERAGE.  
 
ALSO THE PHILADELPHIA MONTH OF MAY PRECIP TOTAL OF 5.14 INCHES  
RANKS 20TH WETTEST DATING BACK TO 1872. ATLANTIC CITY HAS HAD 4.87  
IS RANKED #21 WETTEST DATING BACK TO 1874 AND WILMINGTON'S (DE)  
5.55 INCHES RANKS 18TH DATING BACK TO 1894.  
 
WE MAY ADD MORE INFORMATION BY 5AM THURSDAY.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...DRAG/ROBERTSON  
NEAR TERM...DRAG 242  
SHORT TERM...DRAG 242  
LONG TERM...ROBERTSON  
AVIATION...DRAG/ROBERTSON  
MARINE...DRAG/ROBERTSON  
CLIMATE...  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab PA Page
The Nexlab NJ Page
The Nexlab DE Page
The Nexlab MD Page Main Text Page