Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Graphics & Text | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 251315 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 915 AM EDT MON MAY 25 2015 .SYNOPSIS... HIGH PRESSURE WILL BE ANCHORED OFF THE EAST COAST THIS WEEK. A WARM FRONT WILL MOVE NORTHWARD THROUGH OUR MID-ATLANTIC REGION TODAY. A COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY AND EVENTUALLY DISSIPATE AS IT MOVES THROUGH THE FORECAST AREA THURSDAY. ANOTHER COLD FRONT IS FORECAST TO PASS THROUGH THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AIRMASS CONTINUES TO MODIFY TODAY WITH AN INCREASE IN LOW-LEVEL TEMPERATURES EXPECTED WITH A WEAK WARM FRONTAL PASSAGE TO OUR NORTH THIS AFTERNOON. MOST, IF NOT ALL, OF THE ENERGY AND LIFT WITH THE FRONT WILL REMAIN TO OUR NORTH. EVEN WITH MOISTURE STREAMING INTO THE REGION THE LACK OF LIFT AND SUBSIDENCE ALOFT, AS RIDGING REMAINS ENTRENCHED TO OUR SOUTHEAST, WILL KEEP OUR REGION DRY...AGAIN. WE SHOULD BE ABLE TO MIX UPWARDS OF 850MB, IF NOT HIGHER, THIS AFTERNOON KEEPING OUR DEWPOINTS IN CHECK WITH WIDESPREAD WIND GUSTS UPWARDS OF 25 MPH THIS AFTERNOON. TODAYS STRONGER SOUTHWESTERLY FLOW, BEHIND THE FRONTAL PASSAGE, AND BEING FULLY WITHIN THE WARM SECTOR A VERY WARM DAY IS EXPECTED. EVEN THOUGH 850MB TEMPERATURES MAY NOT COMPLETELY SUPPORT UPPER-80S FOR HIGHS TODAY, GIVEN THE AMOUNT OF SUNSHINE EXPECTED AND THE VERY DRY GROUND IN PLACE, WE SHOULD HAVE SOME HOME COOKING AND ADD A COUPLE DEGREES ON THE STAT GUIDANCE. NO MAJOR CHANGES WITH THE MRNG UPDATE ON THIS QUIET MEMORIAL DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... NOT MUCH CHANGE FROM THE PREVIOUS COUPLE OF NIGHTS, JUST A WARMER STARTING POINT AND MORE MOISTURE SURGING INTO THE REGION. WE DO NOT COMPLETELY DECOUPLE SO WE CONTINUE WITH SOME BOUNDARY LAYER MIXING, THOUGH NOT MUCH IN THE WAY OF GUSTS. THE ADDED MIXING WILL KEEP TEMPERATURES WELL ABOVE NORMAL FOR THE OVERNIGHT PERIOD WITH LOWS ONLY DROPPING INTO THE LOW TO MID-60S...SLIGHTLY COOLER IN THE PINE BARRENS AND ALONG THE COAST. WE CONTINUE WITH A DRY FORECAST TONIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL REMAIN ANCHORED OVER THE WESTERN ATLANTIC OCEAN THIS WEEK AND EVEN INTO NEXT WEEKEND. DEEP SOUTHERLY RETURN FLOW AROUND THE OFFSHORE HIGH WILL YIELD A SUMMER-LIKE PATTERN WITH ABOVE NORMAL TEMPERATURES, INCREASING HUMIDITY AND A SEEMINGLY DAILY CHANCE OF SHOWERS AND STORMS THROUGH MUCH OF THE LONG-TERM PERIOD. BOTH THE HEAT AND HUMIDITY WILL BE FACTOR ON WEDNESDAY WHEN HEAT INDICES MAY REACH 90-92F IN THE URBAN CORRIDOR. CONVECTIVE INITIATION ON TUESDAY WILL BE FAVORED OVER THE HIGHER ELEVATIONS. SINCE TERRAIN CIRCULATIONS APPEAR TO BE PRIMARY LIFTING MECHANISM FOR SHOWERS AND STORMS AND LARGE-SCALE SUBSIDENCE WILL BE STRONGER FARTHER EASTWARD AS YOU GET CLOSER TO THE UPPER RIDGE THAT IS JUST OFFSHORE, CONVECTION WILL MAINLY BE CONFINED TO NE PA AND NW NJ DURING THE AFTERNOON. CHANCES FOR SHOWERS AND STORMS INCREASE WEDNESDAY AND THURSDAY AS TROUGHING DEVELOPS OVER THE GREAT LAKES AND NORTHEAST STATES. NWP GUIDANCE SHOWS SEVERAL SHORTWAVE TROUGHS MOVING THRU THE FORECAST AREA WHICH WOULD PROVIDE THE REQUIRED LIFT FOR MORE ORGANIZED CONVECTION. AN COLD FRONT IS EXPECTED TO DISSIPATE AS IT MOVES THROUGH THE FORECAST AREA. DEPENDING ON HOW QUICKLY IT WASHES OUT, IT MAY PROVIDE ADDITIONAL FOCUS FOR CONVECTION THURSDAY AFTERNOON AND NIGHT. THE HIGHEST POPS GENERALLY RESIDE WEST OF I-95 BOTH DAYS, WHERE MODELS SHOW A CORRIDOR OF GREATER INSTABILITY AND LIFT. UPPER RIDGING IS EXPECTED TO DEVELOP OVER THE EASTERN SEABOARD FRIDAY IN WAKE OF THURSDAY`S TROUGH. THE 00Z GFS/CANADIAN/ECMWF MODELS ALL SHOW A PIECE OF ENERGY ASSOCIATED WITH THE AFOREMENTIONED TROUGH`S PV TAIL HANGING BACK UNDERNEATH THE RIDGE. IT MAY KEEP CLOUDS AROUND AND PROVIDE LIFT FOR ADDITIONAL SHOWERS AND STORMS FRIDAY IF IT DOES BECOME TRAPPED UNDERNEATH RIDGE. THIS FEATURE IS RATHER SUBTLE WITH INHERENTLY LIMITED PREDICTABILITY THIS FAR OUT. A LOW PRESSURE SYSTEM IS FORECAST TO MOVE EASTWARD THROUGH EASTERN CANADA NEXT WEEKEND. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM MAY APPROACH THE AREA DURING THIS TIME. THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE FROPA, BUT IT WILL ENHANCE THE CHANCES FOR SHOWERS AND STORMS. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY - TONIGHT...VFR. SOUTHERLY WINDS INCREASE LATER THIS MORNING AND VEER TOWARDS THE WEST OF SOUTH BY THE AFTERNOON HOURS. EXPECTING GUSTS INTO THE LOW-20 KNOTS RANGE TO OCCUR TODAY. NOT SURE A TRUE EAST-SOUTHEAST SEABREEZE MAKES ITS WAY ACY WITH THE STRONGER WINDS EXPECTED THIS AFTERNOON. BY LATER THIS EVENING THE GUSTS BEGIN TO DROP OFF BUT WE KEEP WINDS 8-10 KNOTS THROUGH THE OVERNIGHT PERIOD. OUTLOOK... TUESDAY THROUGH FRIDAY...PATCHY RADIATIONAL FOG IS POSSIBLE IN THE EARLY MORNING EACH DAY. ISOLATED SHOWERS AND STORMS NEAR RDG/ABE TUESDAY AFTERNOON. DAILY CHANCES FOR SHOWERS AND STORMS EXPAND TO ALL TERMINALS WEDNESDAY THROUGH FRIDAY. COVERAGE OF CONVECTION WILL LIKELY BE HIGHEST ON THURSDAY. && .MARINE... TODAY AND TONIGHT...SMALL CRAFT FOR THE NORTHERN HALF OF OUR WATERS GOES INTO EFFECT THIS AFTERNOON AS STRONGER SOUTHERLY WINDS COMMENCE. FREQUENT 25 TO 30 KNOTS GUSTS EXPECTED THROUGH THE OVERNIGHT TIME PERIOD BEFORE SUBSIDING TOWARDS DAYBREAK ON TUESDAY. SEAS WILL RAMP UP TOWARDS 5 FEET ACROSS THE NORTHERN WATERS UNDER THE INCREASING SOUTHERLY FETCH. OUTLOOK... TUESDAY AND WEDNESDAY...SOUTHERLY WINDS WILL GUST 20-25 KT DURING THE AFTERNOON HOURS EACH DAY, ESPECIALLY ALONG THE COAST AS THE DEEPEST MIXING WILL OCCUR ON LAND. CONFIDENCE FOR 25 KT GUSTS NOT HIGH ENOUGH TO EXTENT THE CURRENT SCA INTO TUESDAY. SEAS MAY ALSO APPROACH 5 FT TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. THURSDAY AND FRIDAY...WINDS AND WAVES WILL BE BELOW SCA THRESHOLD. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM EDT TUESDAY FOR ANZ450>452. && $$ SYNOPSIS...KLEIN NEAR TERM...HEAVENER/NIERENBERG SHORT TERM...HEAVENER LONG TERM...KLEIN AVIATION...HEAVENER/KLEIN MARINE...HEAVENER/KLEIN

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