212  
FXUS61 KPHI 011350  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
950 AM EDT WED JUL 1 2015  
   
SYNOPSIS
 
 
A WARM FRONT WILL LIFT NORTHEAST OF THE AREA THIS MORNING. A COLD  
FRONT FROM THE EASTERN GREAT LAKES SHOULD THEN MOVE THROUGH LATE  
TONIGHT. THE COLD FRONT IS EXPECTED TO STALL JUST SOUTH OF OUR  
REGION FOR THE REMAINDER OF THE WEEK AS WAVES OF LOW PRESSURE MOVE  
ALONG IT. A SECOND COLD FRONT SHOULD ARRIVE SATURDAY NIGHT  
FOLLOWED BY WEAK HIGH PRESSURE FOR SUNDAY. A WARM FRONT SHOULD  
THEN MOVE THROUGH THE REGION ON MONDAY WITH A COLD FRONT REACHING  
THE GREAT LAKES ON TUESDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
MORNING SHOWERS HAVE LEFT OUR REGION AND WE SHOULD HAVE A LULL IN  
THE PRECIPITATION THROUGH MID DAY. HOWEVER, AS THE COLD FRONT  
APPROACHES LATER IN THE DAY AND ANOTHER SHORT WAVE/VORTICITY  
IMPULSE MOVES ACROSS THE AREA, SCATTERED SHOWERS/THUNDERSTORMS MAY  
ONCE AGAIN DEVELOP ACROSS THE AREA, ESPECIALLY THE WESTERN HALF.  
 
HIGHS TODAY ARE A BLEND OF MAV/MET MOS AND MOSGUIDE AND MIXED 925 MB  
ECMWF TEMPERATURES.  
 
PRESSURE GRADIENT MAY TIGHTEN BY MID DAY, THUS A BRIEF PERIOD OF WINDS  
GUSTING AROUND 20-25 MPH WILL BE POSSIBLE THIS AFTERNOON.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
 
 
THE COLD FRONT WILL MOVE ACROSS THE AREA THIS EVENING, WHILE THE  
SHORT WAVE/VORTICITY ALOFT FOLLOWS ALONG. THERE WILL CONTINUE TO BE  
THE CHANCE FOR ISOLATED SHOWERS/THUNDERSTORMS THIS EVENING, BEFORE  
THEY DIMINISH AND MOVE OUT OF THE AREA AS THE FRONT MOVES EASTWARD.  
THE ENTIRE AREA SHOULD BE RAIN FREE BY MIDNIGHT.  
 
LOWS TONIGHT ARE A BLEND OF MAV/MET MOS AND MOSGUIDE.  
 
THE COLD FRONT PUSHES SOUTH OF THE AREA AND STALLS OUT THURSDAY INTO  
THURSDAY NIGHT. WHILE THE FRONT WILL BE WELL SOUTH OF THE AREA,  
THERE WILL REMAIN SEVERAL SHORT WAVE/VORTICITY IMPULSES SLIDING  
ACROSS OUR SOUTHERN AREAS. THE MAJORITY OF THE PRECIPITATION SHOULD  
REMAIN TO OUR SOUTH, BUT THERE WILL REMAIN THE POSSIBILITY FOR  
SHOWERS/THUNDERSTORMS TO AFFECT SOUTHERN NEW JERSEY AND THE DELMARVA.  
 
HIGHS THURSDAY ARE A BLEND OF MAV/MET MOS AND MOSGUIDE AND MIXED 925  
MB ECMWF TEMPERATURES. LOWS THURSDAY NIGHT ARE A BLEND OF MAV/MET  
MOS AND MOSGUIDE.  
 

 
   
LONG TERM /FRIDAY THROUGH TUESDAY/
 
 
THE WRF-NMMB LOOKED BETTER AT 500MB AND 850MB WITH AN EQUAL SPLIT  
AT 925MB. THIS CASTS SOME DOUBT ON THE GFS SOLUTION FOR THE LONG  
TERM. THERE REMAINS BOTH A TIMING AND LATITUDINAL SPLIT WITH THE  
MEDIUM RANGE MODELS WITH THE GFS SLOWEST AND FARTHEST NORTH.  
THERE APPEARS TO BE SOME FEEDBACK VORTS WITH THE GFS AND THE GEFS  
PCPN MEAN IS LOWER THAN THE OP. REGARDLESS ONGOING SVR AND FLOODING  
HAS MADE US LEAN HEAVILY ON PMDHMD (ECMWF PREFERENCE) AND WPC FOR  
THE LONG TERM.  
 
FRIDAY, WE ARE KEEPING A CHANCE FOR SHOWERS IN THE SOUTHERN HALF OF  
OUR CWA. MAX TEMPS HIGHER THAN MEX GUIDANCE, BUT LOWER THAN PREVIOUS  
FORECAST.  
 
PRESERVATION OF CONTINUITY WE KEPT A CHANCE OF THUNDERSTORMS IN  
FOR INDEPENDENCE DAY. HERE THE ECMWF IS MORE PESSIMISTIC. SUNDAY  
CONTINUES TO BE THE CONSENSUS BETTER WEEKEND DAY WITH THE FRONTAL  
BOUNDARY PUSHED FARTHER TO THE SOUTH.  
 
THE RETURNING WARM FRONT SHOULD THEN BRING PCPN CHANCES BACK ON  
MONDAY AND THE APPROACHING COLD FRONT PROVIDING AN ADDITIONAL CHANCE  
COME TUESDAY.  
 
UNCERTAINTY REMAINS HIGHER THAN AVERAGE, BUT TEMPERATURES FAVOR AT  
OR COOLER THAN NORMAL THROUGH INDEPENDENCE DAY WITH A RETURN OF MORE  
WARMER AND HUMID WEATHER FOR THE BACK END OF THE LONG TERM.  
 

 
   
AVIATION /14Z WEDNESDAY THROUGH SUNDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,  
KMIV, KACY AND SURROUNDING AREAS.  
 
A FEW AREAS OF MVFR CEILINGS WILL QUICKLY LIFT OUT OF THE ARE THIS  
MORNING LEADING TO MOSTLY VFR CONDITIONS FOR THE REST OF THE DAY.  
THERE IS A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS LATER TODAY  
ACROSS THE AREA, BUT CHANCE IS TOO LOW TO MENTION IN THE TAF AT  
THIS TIME.  
 
SOUTH-SOUTHWEST WINDS EARLY THIS MORNING WILL BECOME MORE  
SOUTHWESTERLY LATER THIS MORNING INTO THIS AFTERNOON. WINDS WILL  
ALSO GUST 15-20 KNOTS THIS AFTERNOON, BEFORE THE GUSTS DROP OFF  
AROUND SUNSET AND BECOME MORE WEST-NORTHWEST OVERNIGHT. WINDS MAY  
ACTUALLY BECOME LIGHT AND VARIABLE FOR MANY AREAS OVERNIGHT.  
 
VFR CONDITIONS WILL REMAIN FOR THE FIRST PART OF TONIGHT, BUT THERE  
IS THE POSSIBILITY THAT SOME LIGHT FOG MAY DEVELOP OVERNIGHT THROUGH  
DAYBREAK THURSDAY.  
 
OUTLOOK...  
THURSDAY THROUGH SATURDAY...PREDOMINATELY VFR, BUT SOME MVFR OR  
IFR CONDITIONS DURING SCATTERED SHOWERS AND THUNDERSTORMS. IMPACT  
OUTLOOKED TO BE GREATER FOR SOUTHERN AIRPORTS AND TERMINALS.  
 
SATURDAY NIGHT AND SUNDAY...VFR CONDITIONS EXPECTED.  
 

 
   
MARINE
 
 
A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS HAS BEEN ISSUED FOR THE  
ATLANTIC COASTAL WATERS FOR TODAY INTO TONIGHT. SEAS ARE AROUND 4  
FEET EARLY THIS MORNING AND ARE EXPECTED TO INCREASE TO 5 FEET  
THROUGH THE DAY. THE SMALL CRAFT ADVISORY ON THE BAY HAS BEEN  
CANCELLED AS WINDS CONTINUE TO DIMINISH.  
 
OUTLOOK...  
THURSDAY AND THURSDAY NIGHT...WINDS AND SEAS SHOULD REMAIN BELOW SCA  
CRITERIA.  
 
FRIDAY THROUGH SATURDAY...SEAS ON THE SOUTHERN OCEAN WATERS MIGHT  
REACH SMALL CRAFT ADVISORY LEVELS PENDING THE STRENGTH OF THE LOW  
PRESSURE SYSTEM ON THE FRONTAL BOUNDARY. CONFIDENCE IS LESS THAN  
AVERAGE.  
 
SUNDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED.  
 

 
   
RIP CURRENTS
 
 
BASED ON OUR LOCAL FORECAST APPLICATION USING A 5 FOOT WAVES/7  
SECOND PERIOD AND SOUTHWEST WIND AROUND 12 KNOTS, WE WILL CONTINUE  
WITH A MODERATE RISK OF RIP CURRENTS FOR NEW JERSEY AND LOW FOR  
DELAWARE.  
 

 
   
CLIMATE
 
 
RAINFALL FOR THE MONTH OF JUNE RANKED IN THE TOP 5 OF THE AVAILABLE  
RELIABLE HISTORICAL DATABASE.  
 
WILMINGTON #2 12.52. THE WETTEST WAS 13.66 IN 2013 AND THE TOP 4  
WETTEST JUNES OCCURRED SINCE 2003. THE PERIOD OF RECORD (POR)  
DATES BACK TO 1894.  
 
ALLENTOWN #5 7.59 INCHES. THE WETTEST 10.51 IN 1938. POR TO 1922.  
10.51 1938 THREE OF THE WETTEST JUNES OCCURRED SINCE 2003  
9.13 2006  
8.58 1972  
8.30 2003  
7.59 2015  
 
ATLANTIC CITY #2 8.36 INCHES. THE WETTEST 8.45 INCHES 1920. POR  
1874.  
 
PHILADELPHIA #3 8.88 INCHES. THE WETTEST 10.56 2013, #2 IS 10.06  
IN 1938. THREE OF 4 WETTEST JUNES OCCURRED SINCE 2003.  
 
TEMPERATURES FOR THE MONTH OF JUNE IN OUR FORECAST AREA GENERALLY  
AVERAGED SLIGHTLY ABOVE NORMAL BUT NOTHING OF SIGNIFICANCE.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT  
THURSDAY FOR ANZ450>455.  
 

 
 

 
SYNOPSIS...GIGI  
NEAR TERM...JOHNSON/ROBERTSON  
SHORT TERM...ROBERTSON  
LONG TERM...GIGI  
AVIATION...GIGI/JOHNSON/ROBERTSON  
MARINE...GIGI/JOHNSON/ROBERTSON  
RIP CURRENTS...  
CLIMATE...DRAG  
 
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