328  
FXUS61 KPHI 111405  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
1005 AM EDT THU AUG 11 2022  
   
SYNOPSIS
 
 
A STATIONARY FRONT WILL REMAIN IN PLACE TODAY ACROSS THE  
DELMARVA WHILE A WAVE OF LOW PRESSURE RIDES ALONG IT OUT TO SEA.  
A STRONGER COLD FRONT WILL THEN CROSS OUR REGION TONIGHT INTO  
FRIDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR SATURDAY  
BEFORE WEAKENING SUNDAY. ANOTHER STORM SYSTEM WILL ARRIVE EARLY  
NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
ONLY SIGNIFICANT CHANGE TO THE FORECAST FOR THE MID-MORNING  
UPDATE WAS TO HOLD ONTO SOME ISOLATED POPS FOR A FEW MORE HOURS  
MAINLY OVER THE DELMARVA WHERE A COUPLE SHOWERS ARE HANGING  
BACK. OTHERWISE, INHERITED FORECAST IS ON TRACK.  
   
..4AM DISCUSSION
 
 
THE SURFACE COLD FRONT WHICH STALLED ACROSS THE SOUTHERN ZONES  
THIS AFTERNOON HAS SINCE RETREATED NORTH AS A WARM FRONT AS A  
700/ 500 MB SHORTWAVE RIPPLES EAST ALONG THE BOUNDARY. IN  
RESPONSE TO THE SHORTWAVE, CONVECTION HAS BEEN TRACKING EAST  
ALONG THE PA/ MD BORDER THIS MORNING AND IS CURRENTLY  
APPROACHING THE I-95 CORRIDOR. AS THE SHORTWAVE EXITS EAST THIS  
MORNING, A WEAK COLD FRONT WILL SLIP OFF THE DE AND NJ COAST  
WITH DEWPOINTS FALLING INTO THE LOWER 60S. THE PRIMARY COLD  
FRONT WILL BE HELD BACK AS THE LONGWAVE TROUGH AXIS REMAINS  
CENTERED OVER THE OHIO RIVER VALLEY. LATER THIS AFTERNOON A  
SEABREEZE WILL START TO PUSH INLAND AROUND 10 TO 20 MILES AND  
QUICKLY COME TO A HALT. SOME HIGH RES GUIDANCE IS INDICATING  
THAT AN ISOLATED SHOWER AND THUNDERSTORM WILL BE POSSIBLE ALONG  
THE SEA BREEZE, BUT PWATS DO FALL OFF TO AROUND 1.10” WITH A  
SIGNIFICANT DRY SLOT MOVING OVERHEAD AS WELL. GIVEN THE ABOVE,  
DRY AIR ENTRAINMENT WILL LIKELY KEEP MOST UPDRAFTS IN CHECK, BUT  
AN ISOLATED SHOWER AND THUNDERSTORM CAN’T BE RULED OUT  
(ESPECIALLY NEAR THE COAST). TEMPERATURES TODAY WILL LIKELY  
AGAIN BE WARM, WITH HIGHS APPROACHING OR JUST TOUCHING THE 90  
DEGREE MARK.  
 
THIS EVENING, THE PRIMARY COLD FRONT WILL APPROACH THE AREA  
FROM THE NORTHWEST AS THE LONGWAVE TROUGH AXIS PROGRESSES EAST.  
THE FRONT WILL MOSTLY BE A DRY FRONTAL PASSAGE WITH DEWPOINTS  
FALLING INTO THE UPPER 50S FOR MOST OF THE AREA BY FRIDAY  
MORNING.  
 

 
   
SHORT TERM /FRIDAY THROUGH SUNDAY/
 
 
THE CORE OF THE DCVA WILL TRANSLATE OVERHEAD FRIDAY WITH SKIES  
BEGINNING TO SLOWLY CLEAR DURING THE DAY AND TEMPERATURES MUCH  
COOLER WITH LOWER HUMIDITY VALUES. EXPECT HIGH TEMPERATURES IN  
THE LOW 80S FRIDAY WITH NO PRECIPITATION EXPECTED. ON SATURDAY,  
THE SHORTWAVE EMBEDDED IN THE LONGWAVE TROUGH AXIS WILL WRAP UP  
INTO A CLOSED LOW ACROSS NEW ENGLAND ALLOWING FOR THE DELAWARE  
RIVER VALLEY TO FALL INTO THE AGEOSTROPHIC CONVERGENT SIDE OF  
THE TROUGH AXIS. EXPECT MOSTLY CLEAR SKIES WITH HIGHS IN THE  
LOWER 80S AND RELATIVE HUMIDITY VALUES IN THE LOWER 30% RANGE.  
 
ON SUNDAY, THE SURFACE HIGH PRESSURE THAT WAS OVERHEAD ON  
SATURDAY WILL BEGIN TO LOSE COHESION AS THE AGEOSTROPHIC  
CONVERGENCE COLLAPSES DUE TO AN IMPINGING SHORTWAVE DIVING  
SOUTHEAST OUT OF THE GREAT LAKES REGION. GLOBAL MODELS ARE  
INDICATING PRECIPITATION MOVING INTO THE REGION SUNDAY  
AFTERNOON, BUT UPON FURTHER INVESTIGATION OF FORECAST SOUNDINGS  
AM NOT SO SURE. COMPLETE SATURATION ABOVE 600 MB IS FORECAST,  
BUT IN THE LOW LEVELS DEW POINT DEPRESSIONS ARE FORECAST TO BE  
LARGE. DUE TO THIS, I HAVE KEPT MOST OF THE REGION DRY THROUGH  
THE DAY SUNDAY. EXPECT HIGH TEMPERATURES IN THE LOW TO MID 80S.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
 
 
THE LONG TERM PERIOD LOOKS TO BE DEFINED BY A SIGNIFICANT  
PATTERN CHANGE FOR NEXT WEEK. ENSEMBLE AND DETERMINISTIC  
GUIDANCE CONTINUES TO HINT AT A LONGWAVE TROUGH SETTING UP OVER  
THE EASTERN US, WHICH WOULD BRING BELOW AVERAGE TEMPERATURES AND  
THE POTENTIAL FOR SOME MUCH NEEDED RAIN.  
 
GETTING INTO THE DAY-BY-DAY PORTION OF THE DISCUSSION, A  
SHORTWAVE WILL SWING THROUGH LATE SUNDAY NIGHT/EARLY MONDAY  
MORNING. AT THE SURFACE, AN AREA OF LOW PRESSURE LOOKS TO  
DEVELOP OVER THE OHIO RIVER VALLEY, INCHING TOWARD OUR AREA  
GETTING INTO MONDAY. THIS WILL RESULT IN A RATHER WET AND  
UNSETTLED MONDAY. HAVE GONE LIKELY POPS FOR MOST OF THE REGION  
AS SOME NEEDED RAIN LOOKS TO MOVE THROUGH MONDAY AFTERNOON AND  
EVENING. SEVERE THREAT LOOKS RATHER LIMITED, THOUGH WE WILL HAVE  
TO MONITOR THE POTENTIAL HYDRO THREAT. CONFIDENCE IS QUITE HIGH  
THAT TEMPERATURES WILL BE BELOW NORMAL, WITH HIGHS AROUND 80  
FOR DELMARVA, PHILADELPHIA, AND THE NJ COASTAL PLAIN. LOOKING AT  
UPPER 70S NORTH AND WEST OF PHILADELPHIA, WITH TEMPERATURES IN  
THE POCONOS POTENTIALLY NOT GETTING OUT OF THE 60S.  
 
DETERMINISTIC GUIDANCE REMAINS PRETTY CONSISTENT IN A STRONG  
SHORTWAVE MOVING IN FROM THE NORTH, WITH A CLOSED LOW EVENTUALLY  
FORMING AT 500 MB LATE MONDAY/EARLY TUESDAY. STILL SOME  
UNCERTAINTY IN HOW FAR SOUTH THE CLOSED LOW GETS, BUT THERE IS  
INCREASING CONFIDENCE ON ANOTHER MILD AND UNSETTLED DAY ON  
TUESDAY. HAVE HIGH END CHC AND LOW END LIKELY POPS FOR TUESDAY  
AS THE SURFACE LOW COULD SLIDE THROUGH THE SOUTHERN PORTION OF  
OUR CWA. WITH THE MEANDERING 500 MB LOW REMAINING CLOSE BY, THE  
SURFACE LOW IS EXPECTED TO TRACK SLOWLY NORTHEASTWARD AWAY FROM  
THE NJ COAST, LIKELY BRINGING ANOTHER WET AND MILD DAY ON  
WEDNESDAY. WITH THE RATHER SLOW MOVEMENT OF THE SURFACE LOW,  
THERE COULD BE A PROLONGED PERIOD OF ONSHORE FLOW, WHICH COULD  
RESULT IN SOME COASTAL FLOODING. CONFIDENCE IS LOW IN ANY  
SPECIFIC IMPACTS AT THIS TIME, BUT WILL BECOME MORE CLEAR AS WE  
GET CLOSER. BOTH TUESDAY AND WEDNESDAY WILL FEATURE TEMPERATURES  
IN THE MID TO UPPER 70S, SOMETHING NOT SEEN IN QUITE SOME TIME  
AROUND HERE. OVERALL, EARLY NEXT WEEK WILL FEATURE SOME GOOD  
RAIN CHANCES TO HELP THE REGION WITH THE ONGOING DROUGHT  
CONCERNS.  
 

 
   
AVIATION /14Z THURSDAY THROUGH MONDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
TODAY... VFR CONDITIONS WILL PREVAIL THROUGH THE REST OF THE  
DAY. NORTHWESTERLY WINDS AROUND 5-10 KTS. AN ISOLATED SHOWER IS  
POSSIBLE. HIGH CONFIDENCE IN PREVAILING VFR CONDITIONS.  
 
TONIGHT...VFR. NORTHERLY WINDS AROUND 5-10 KTS. HIGH  
CONFIDENCE.  
 
OUTLOOK…  
 
FRIDAY THROUGH SATURDAY...VFR. NORTHERLY WINDS 5-10 KTS. SOME  
GUSTS UP TO 20 KTS POSSIBLE ON FRIDAY. HIGH CONFIDENCE.  
 
SUNDAY…VFR. SOUTHWEST WINDS 5-10 KTS. HIGH CONFIDENCE.  
 
MONDAY...PREVAILING VFR, BUT SCATTERED SHOWERS AND  
THUNDERSTORMS MAY INTRODUCE SOME BRIEF RESTRICTIONS. SOUTHERLY  
WINDS 5-10 KTS. MODERATE CONFIDENCE.  
 

 
   
MARINE
 
 
NO MARINE HEADLINES ANTICIPATED THROUGH TONIGHT. WESTERLY WINDS  
5-10 KTS THIS MORNING WILL SHIFT SOUTH TO SOUTHWESTERLY THIS  
AFTERNOON. WINDS WILL SHIFT TO THE NORTH OVERNIGHT AROUND 15 KTS  
WITH GUSTS UP TO 20 KTS. SEAS AROUND 2 FEET.  
 
A CLUSTER OF HEAVY SHOWERS AND THUNDERSTORMS WILL MOVE OFF OF  
THE NEW JERSEY COAST THROUGH MID-MORNING. OTHERWISE, FAIR  
WEATHER IS EXPECTED WITH AN ISOLATED SHOWER OR THUNDERSTORM  
POSSIBLE THROUGH TONIGHT.  
 
OUTLOOK...  
 
FRIDAY THROUGH SATURDAY...NO MARINE HEADLINES ANTICIPATED.  
NORTH TO NORTHEASTERLY WINDS 10-15 KTS WITH GUSTS UP TO 20 KTS.  
SEAS 2-3 FEET. FAIR WEATHER.  
 
SUNDAY THROUGH MONDAY...NO MARINE HEADLINES ANTICIPATED. WINDS  
WILL SETTLE OUT OF THE SOUTH AROUND 10-15 KTS. SEAS 2-3 FEET.  
SCATTERED SHOWERS AND THUNDERSTORMS ON MONDAY.  
 
RIP CURRENTS...  
 
WINDS WILL START OFFSHORE IN THE MORNING THEN SHIFT ONSHORE INTO  
THE AFTERNOON AROUND 10 MPH. BREAKING WAVES OF 1-2 FEET WITH A  
MEDIUM SOUTH TO SOUTHWEST SWELL WILL RESULT IN A LOW RISK OF RIP  
CURRENTS.  
 
A NORTHERLY WIND AROUND 15-20 MPH IS EXPECTED ON FRIDAY. THIS  
COMBINED WITH A BUILDING NORTHERLY SWELL AND BREAKERS OF 2-3 FEET  
WILL RESULT IN A LOW RISK OF RIP CURRENTS.  
 

 
   
TIDES/COASTAL FLOODING
 
 
THE FULL MOON OCCURS THIS EVENING. THE EVENING HIGH TIDES TODAY  
AND FRIDAY WILL BE PARTICULARLY HIGH EVEN WITHOUT ANY CONTRIBUTION  
FROM THE WIND.  
 
WHILE SOME LOCALIZED TIDAL FLOODING OCCURRED LAST EVENING IN  
THE COASTAL COUNTIES OF NEW JERSEY AND DELAWARE, AND ALONG  
DELAWARE BAY, THE MINOR TIDAL FLOODING MAY BECOME MORE  
WIDESPREAD BOTH THIS EVENING AND FRIDAY EVENING. THE LATEST  
FORECAST GUIDANCE SUGGESTS THAT WE MAY NEED ADVISORIES FOR PARTS  
OF OUR REGION AT THOSE TIMES.  
 

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

 
 

 
SYNOPSIS...RCM  
NEAR TERM...HAINES/RCM  
SHORT TERM...HAINES  
LONG TERM...HOEFLICH  
AVIATION...STAARMANN/RCM  
MARINE...STAARMANN  
TIDES/COASTAL FLOODING...WFO PHI  
 
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