Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 040737 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 337 AM EDT FRI SEP 4 2015 .SYNOPSIS...
-- Changed Discussion --
A BACKDOOR COLD FRONT WILL MOVE ACROSS OUR AREA THIS MORNING. HIGH PRESSURE WILL THEN BUILD INTO OUR REGION FROM THE NORTH SATURDAY INTO SUNDAY BEFORE MOVING OFFSHORE EARLY NEXT WEEK. A COLD FRONT IS SCHEDULED TO APPROACH LATE WEDNESDAY, THEN MOVE THROUGH OUR REGION DURING THURSDAY.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
THE BACK DOOR COLD FRONT THAT WAS DROPPING THROUGH OUR REGION REMAINED DIFFUSE AND RATHER DIFFICULT TO FIND AROUND 330 AM. REGARDLESS, THE WIND IS EXPECTED TO SHIFT TO THE NORTHEAST IN MOST OF OUR FORECAST AREA BY 800 AM. AN AREA OF STRATOCUMULUS THAT WAS DEVELOPING OVER PARTS OF NEW ENGLAND AND THE ADJACENT WATERS EARLY THIS MORNING WILL MOVE SOUTHWESTWARD AND OVER OUR REGION TODAY. AS A RESULT, WE ARE ANTICIPATING AN INCREASE IN CLOUD COVER. AN IMPULSE IN THE MID LEVEL FLOW IS EXPECTED TO DRIFT SOUTHWARD OVER OUR REGION TODAY. IT MAY TOUCH OFF A FEW RAIN SHOWERS. THE AXIS OF BEST INSTABILITY IN OUR VICINITY IS FORECAST TO EXTEND FROM CENTRAL VIRGINIA UP INTO CENTRAL PENNSYLVANIA FOR THIS AFTERNOON. WE WILL MENTION THE POTENTIAL FOR AFTERNOON THUNDERSTORMS IN SOUTHEASTERN PENNSYLVANIA, ON THE UPPER DELMARVA AND IN PARTS OF SOUTHWESTERN NEW JERSEY. LOCATIONS NEAR THE COAST AND IN THE NORTHEASTERN PART OF OUR FORECAST AREA SHOULD BE RELATIVELY STABLE AND WILL LIKELY NOT EXPERIENCE THUNDERSTORM ACTIVITY. THE CLOUD COVER AND THE NORTHEASTERLY FLOW SHOULD KEEP MAXIMUM TEMPERATURES MAINLY IN THE 80S FOR TODAY.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
-- Changed Discussion --
AS THE CENTER OF HIGH PRESSURE DROP FROM QUEBEC INTO NEW ENGLAND FOR TONIGHT, DRY AIR WILL CONTINUE TO PUSH INTO OUR REGION. SOME CLEARING IS EXPECTED FROM THE NORTHEAST AND ANY CHANCE OF PRECIPITATION WILL BE PUSHED TO THE SOUTHWEST AND SOUTH OF OUR FORECAST AREA. THE WIND WILL REMAIN FROM THE NORTHEAST FOR TONIGHT AND TEMPERATURES SHOULD DROP INTO THE 60S AT MOST LOCATIONS. READINGS ARE ANTICIPATED TO FALL INTO THE UPPER 50S IN THE POCONO REGION AND IN FAR NORTHERN NEW JERSEY.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
THE SYNOPTIC SETUP IS COMPRISED OF A RIDGE ACROSS THE EAST AND A TROUGH IN THE WEST. AS THE TROUGH EJECTS EASTWARD ACROSS THE NORTHERN PLAINS AND MIDWEST SUNDAY INTO MONDAY, THE PORTION OF THE RIDGE IN THE NORTHEAST AND MID ATLANTIC IS FORECAST TO FLATTEN. THE TROUGH OR ANOTHER ONE BEHIND IT GRADUALLY SLIDES EAST-NORTHEAST THROUGH THURSDAY, HOWEVER THE RIDGE WHILE GETTING PUSHED SOUTHEASTWARD IT TENDS TO SLOW THE EASTWARD PROGRESSION OF THE INCOMING SYSTEM. THIS PATTERN TENDS TO FAVOR WARMTH AND DRYNESS ALTHOUGH A BREAK OCCURS SATURDAY INTO SUNDAY IN THE WAKE OF A BACKDOOR COLD FRONT. THE REGION NEEDS RAIN, HOWEVER IT LOOKS LIKE THE CHCS ARE RATHER LOW GIVEN NO ORGANIZED SYSTEMS MOVING THROUGH. WE USED A MODEL/CONTINUITY BLEND FOR SATURDAY INTO MONDAY, WITH A 00Z WPC GUIDANCE/CONTINUITY BLEND THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE AFTER ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR SATURDAY AND SUNDAY...AS THE UPPER-LEVEL RIDGE CRESTS ACROSS THE AREA, SURFACE HIGH PRESSURE SHOULD EASE EASTWARD. THIS WILL ALLOW THE ONSHORE FLOW TO WEAKEN AND EVENTUALLY TURN SOUTHERLY. THE ONSHORE FLOW HOWEVER PERSISTS SATURDAY WITH ENOUGH MOISTURE TO RESULT IN MORE CLOUDINESS FOR A TIME ACROSS THE SOUTHERN ZONES. SOME GUIDANCE SHOWS SOME LIGHT QPF IN PORTIONS OF MARYLAND AND CENTRAL/SOUTHERN DELAWARE, HOWEVER THIS IS OF LOWER CONFIDENCE GIVEN THE SURFACE HIGH BUILDING SOUTHWARD. AS A RESULT, WE WENT WITH A DRY FORECAST BUT DID CARRY MORE CLOUD COVER. A MUCH COOLER DAY IS EXPECTED SATURDAY DUE TO THE ONSHORE FLOW. WE START TO LOSE THE STRENGTH OF THE ONSHORE FLOW SUNDAY, AND THEREFORE THE DAYTIME TEMPERATURES ARE ANTICIPATED TO START REBOUNDING IN THE AFTERNOON FOR MUCH OF THE AREA. THIS WILL BE MORE ACROSS THE INTERIOR COMPARED TO THE COASTAL LOCALES. FOR MONDAY AND TUESDAY...AN UPPER-LEVEL TROUGH TO CLOSED LOW TRACKING FROM THE NORTHERN PLAINS INTO SOUTH-CENTRAL CANADA IS FORECAST TO ALLOW FOR A FLATTER RIDGE IN THE EAST. THIS WILL ALSO FORCE HIGH PRESSURE MORE OFFSHORE, AND A WEAK COLD FRONT SHOULD BE GRADUALLY SLIDING EASTWARD ACROSS THE GREAT LAKES. THE BULK OF THE ENERGY IS FORECAST TO TRACK INTO CANADA TUESDAY, THEREFORE THE CHCS FOR CONVECTION IS EXPECTED TO BE TO OUR WEST. AS THE FLOW IS MORE SOUTHERLY, A RATHER WARM AIRMASS LOOKS TO BE IN PLACE WITH SOME INCREASE IN THE DEW POINTS EACH DAY. THERE IS A WEAK SYSTEM FORECAST TO BE OFF OF THE COAST OF THE CAROLINAS, HOWEVER MOISTURE ASSOCIATED WITH THAT SHOULD REMAIN TO OUR SOUTH GIVEN SURFACE HIGH PRESSURE CLOSER TO OUR AREA. FOR WEDNESDAY AND THURSDAY...SOME GUIDANCE SUGGESTS THE TROUGH TO CLOSED LOW IS FOLLOWED BY A SHORT WAVE TROUGH FROM THE MIDWEST TO THE GREAT LAKES. THIS MAY INDUCE A WEAK SURFACE LOW ALONG THE COLD FRONT, SLOWING IT DOWN SOME MORE. THE COMBINATION OF THIS ALONG WITH THE INITIAL ENERGY TRACKING WELL NORTH AND THE RIDGE FARTHER SOUTH SHOULD RESULT IN A SLOWER FRONTAL PASSAGE. THIS TIMING WILL GOVERNOR THE PROSPECTS FOR THE CONVECTIVE CHCS, HOWEVER THE WPC GUIDANCE SHOWS THE SURFACE FRONT MOVING IN DURING THURSDAY. THIS SHOULD EXTEND THE PERIOD OF RATHER WARM CONDITIONS, HOWEVER THE ARRIVAL OF THE FRONT ON THURSDAY MAY SIGNAL A CHANGE. OVERALL, LOW POPS ARE CARRIED MOSTLY THURSDAY AS THE FRONT ARRIVES.
-- End Changed Discussion --
&& .AVIATION /08Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. SCATTERED MVFR VISIBILITY RESTRICTIONS ARE EXPECTED IN OUR REGION UNTIL ABOUT 1300Z, THEN VFR CONDITIONS ARE ANTICIPATED THROUGH THE BALANCE OF THE TAF PERIOD. A DECK OF STRATOCUMULUS APPROACHING FROM THE NORTHEAST SHOULD OVERSPREAD OUR REGION TODAY. CEILINGS ARE FORECAST TO REMAIN ABOVE 4000 FEET. SCATTERED SHOWERS ARE POSSIBLE FROM ABOUT 1600Z UNTIL 2200Z AND THEY HAVE BEEN MENTIONED FOR ALL OF OUR TAF SITES EXCEPT KTTN AND KACY. CONDITIONS AROUND THOSE TWO TAF SITES AND POINTS TO THE NORTHEAST SHOULD REMAIN MORE STABLE THAN AT LOCATIONS TO THE SOUTHWEST. ALSO, THERE IS THE POTENTIAL FOR ISOLATED THUNDERSTORMS BUT THE RISK IS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS. THE STRATOCUMULUS IS EXPECTED TO PUSH TO THE WEST AND SOUTH OF OUR TAF SITES TONIGHT. THE WIND IS ANTICIPATED TO FAVOR THE NORTHEAST AND EAST THROUGH THE TAF PERIOD AT SPEEDS FROM ABOUT 6 TO 12 KNOTS. OUTLOOK... SATURDAY AND SUNDAY...VFR OVERALL, HOWEVER SOME CLOUDINESS IS POSSIBLE SATURDAY MAINLY SOUTH OF KILG TO KACY. LOCALIZED FOG POSSIBLE LATE SATURDAY NIGHT AND EARLY SUNDAY MORNING. EAST- NORTHEAST WINDS 10-15 KNOTS SATURDAY /STRONGEST CLOSER TO THE COAST/, DIMINISHING SOME AND BECOMING SOUTHEASTERLY SUNDAY. MONDAY AND TUESDAY...VFR OVERALL. SOUTHERLY WINDS LESS THAN 10 KNOTS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
HIGH PRESSURE WILL BUILD SOUTHWARD FROM QUEBEC TODAY AND INTO NEW ENGLAND TONIGHT. AN INCREASING NORTHEAST FLOW IS EXPECTED AND WIND GUSTS SHOULD INCREASE TO AROUND 25 KNOTS DURING THE AFTERNOON. AS A RESULT, WE HAVE A SMALL CRAFT ADVISORY IN EFFECT FOR ALL BUT THE UPPER PART OF DELAWARE BAY WHICH SHOULD BE SHELTERED FROM THE STRONGEST OF THE GUSTS. THE SMALL CRAFT ADVISORY BEGINS AT NOON FOR OUR NORTHERN WATERS AND AT 400 PM FOR OUR SOUTHERN WATERS AND FOR LOWER DELAWARE BAY. WAVE HEIGHTS ON OUR OCEAN WATERS ARE ANTICIPATED TO BUILD TO 4 TO 6 FEET FOR LATE TODAY INTO TONIGHT. WAVE HEIGHTS SHOULD BUILD TO 2 TO 4 FEET ON LOWER DELAWARE BAY AND 1 TO 2 FEET ON THE UPPER BAY. OUTLOOK... SATURDAY...EAST-NORTHEAST WINDS ARE EXPECTED TO GRADUALLY DIMINISH FROM NORTH TO SOUTH AS HIGH PRESSURE BUILDS CLOSER. HOWEVER, STRONG ENOUGH FLOW WITHIN A TIGHTENED PRESSURE GRADIENT WILL RESULT IN WIND GUSTS TO AROUND 25 KNOTS FOR AWHILE MAINLY ON THE ATLANTIC COASTAL WATERS. IT COULD BE CLOSE MAINLY IN THE MORNING FOR LOWER DELAWARE BAY, HOWEVER AS OF NOW DID NOT TAKE THE SMALL CRAFT ADVISORY BEYOND 12Z GIVEN LOWER CONFIDENCE. THE SEAS OF 4-6 FEET ARE EXPECTED ON THE ATLANTIC COASTAL WATERS AS A RESULT OF THE STRONGER ONSHORE FLOW, HOWEVER THESE SHOULD BE SUBSIDING THROUGH THE NIGHT. SUNDAY THROUGH TUESDAY...THE WINDS ARE ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA AS THEY SHIFT FROM EAST-NORTHEAST TO SOUTHEAST AND SOUTH. THE SEAS ARE CURRENTLY ANTICIPATED TO BE BELOW 5 FEET.
-- End Changed Discussion --
&& .RIP CURRENTS...
-- Changed Discussion --
THE THREAT FOR DANGEROUS RIP CURRENTS WILL BE ENHANCED FRIDAY AND THE UPCOMING LABOR DAY WEEKEND. FOR THE FIRST LOOK FOR TODAY, WE WILL CARRY A MODERATE RISK FOR MONMOUTH AND OCEAN COUNTIES AND LOW RISK ELSEWHERE. THIS WILL BE REACCESSED EARLY THIS MORNING AS ITS A TIMING ISSUE AS TO HOW QUICKLY WILL THE NORTHEAST WINDS RAMP AS WE MOVE FARTHER SOUTH ALONG THE NEW JERSEY AND THEN DELAWARE COASTS. COULD BE A HYBRID SCENARIO OF LOW BECOMING MODERATE AS THE AFTERNOON, EVENING CONTINUES. THE NORTHEASTERLY WINDS SURGE BEHIND A BACKDOOR COLD FRONT OF 10 TO 15 KT WILL ARRIVE THIS MORNING AND INCREASE TO 15-20 KT THIS AFTERNOON THRU SATURDAY. WAVES WILL BUILD IN RESPONSE TO THIS WIND SURGE, FORECASTED TO INCREASE TO 4-6 FT BY TONIGHT. FOR SATURDAY AND SUNDAY, THE WINDS AND WAVES ALONG THE COAST SHOULD GRADUALLY SUBSIDE LATE SATURDAY INTO SUNDAY. AS OF NOW, IN-HOUSE GUIDANCE IS SUGGESTING A SOLID MODERATE /POSSIBLY NEARING HIGH/ FOR SATURDAY. THE RISK SHOULD LOWER SOME SUNDAY BUT IT MAY STILL BE MODERATE. IT IS PARTICULARLY IMPORTANT FOR SAFETY AWARENESS TO SHARE THIS INFORMATION TO BEACHGOERS AND LIFEGUARDS WITH THE BEACH CROWD ANTICIPATED TO BE LARGER THAN NORMAL GIVEN IT IS LABOR DAY WEEKEND.
-- End Changed Discussion --
&& .PHI WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM EDT SATURDAY FOR ANZ452>455. SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT SATURDAY FOR ANZ450-451. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 8 AM EDT SATURDAY FOR ANZ431.
-- End Changed Discussion --
&& $$ SYNOPSIS...GORSE NEAR TERM...IOVINO SHORT TERM...IOVINO LONG TERM...GORSE AVIATION...GORSE/IOVINO MARINE...GORSE/IOVINO RIP CURRENTS...GIGI/GORSE

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.