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 012348 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 748 PM EDT MON JUN 1 2015 .SYNOPSIS... A COLD FRONT OVER SOUTHERN NEW JERSEY AND EXTREME SOUTHEAST PENNSYLVANIA THIS AFTERNOON WILL SLOWLY PROGRESS SOUTHWARD THROUGH TUESDAY BEFORE STALLING TO OUR SOUTH TUESDAY NIGHT THROUGH THE END OF THE WEEK. MEANWHILE, HIGH PRESSURE BUILDS IN FROM THE NORTH MIDWEEK BEFORE MOVING OFFSHORE LATE IN THE WEEK. ONSHORE FLOW BETWEEN THE FRONT TO OUR SOUTH AND HIGH PRESSURE TO OUR NORTH WILL LEAD TO COOL AND CLOUDY CONDITIONS FOR MUCH OF THIS WEEK. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE MID-ATLANTIC REGION EARLY THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE SLOW MOVING FRONT HAS PUSHED FURTHER SOUTH SINCE THE AFTERNOON AND IS ACROSS THE DELMARVA EARLY THIS EVENING. SHOWERS AND TSTMS PREVAIL ACROSS THE DELMARVA AND SRN NJ WITH MORE STABLE PRECIP BACK UP ACROSS ERN PA AND THE REST OF NJ. MUCH OF THE STEADY PRECIP IS NOT REACHING THE SRN POCONOS. WE HAVE MADE ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THE RECENT PRECIP TRENDS. TEMPS/DEW POINTS AND WINDS ADJUSTED ALONG THE LINES OF HRRR MODEL. OCNL FLOOD/SVR WARNINGS BEING ISSUED THIS EVENING SO PAY ATTENTION TO THE LATEST STATEMENTS FROM THE NWS. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... THE FRONT WILL TRANSITION SOUTH OF THE REGION ON TUESDAY, LEAVING THE REGION WITH A STIFF ONSHORE EASTERLY FLOW AND THICK CLOUDS. TEMPERATURES MAY ACTUALLY FALL THROUGH THE DAY, PARTICULARLY IF MODELED TWO METER TEMPERATURES HAVE A CORRECT HANDLE OF THE TRENDS. LIGHTER SHOWERS WILL LIKELY CONTINUE WITH SOME QPF UNDER 1/2 INCH. FOR NOW GIVEN THE LOWER TRENDS IN THE MET/MAV THE LAST SEVERAL CYCLES WILL GO A TOUCH LOWER WITH DAYTIME TEMPERATURES ON TUESDAY THAN THOSE GUIDANCE SETS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THE FRONTAL BOUNDARY WILL GRADUALLY PUSH SOUTH OF THE FORECAST AREA TUESDAY EVENING BEFORE STALLING NEAR THE VA-NC BORDER AND THE SOUTHERN TIP OF THE DELMARVA LATE TUESDAY NIGHT THROUGH MIDWEEK. MEANWHILE, HIGH PRESSURE OVER EASTERN CANADA/NORTHERN NEW ENGLAND WILL NOSE SOUTHWARD, WHICH WILL REINFORCE THE ONSHORE FLOW IN THE NORTHERN MID-ATLANTIC REGION. THE FORECAST AREA WILL RESIDE IN A RELATIVELY COOL, STABLE AIRMASS DUE TO PERSISTENT ONSHORE FLOW TO THE NORTH OF THE BOUNDARY. LOW CHANCES FOR SHOWERS WERE ADDED TO THE FORECAST FOR THE SOUTHERN HALF OF CWA FOR MUCH OF THE MIDWEEK, AS THIS AREA IS FORECAST BE POSITIONED CLOSER TO THE MID- AND UPPER- LEVEL DEFORMATION ZONE DOWNSTREAM OF A CUTOFF LOW OVER THE SOUTHERN APPALACHIANS AND JUST UPSTREAM OF A SHORTWAVE RIDGE OVER SOUTHERN NEW ENGLAND. CHANCES/COVERAGE OF SHOWERS WILL BE MUCH LOWER THAN YESTERDAY AND TODAY. ONSHORE FLOW WILL CONTINUE LATE IN THE WEEK BUT WEAKEN AS HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST. THE AIRMASS WILL MODERATE A BIT ACCORDINGLY, WITH NEAR NORMAL TEMPS RETURNING BY FRIDAY. LOW CHANCES FOR SHOWERS EXPAND NORTHWARD TOWARD THE HIGHER ELEVATIONS IN NORTHEAST PA ON THURSDAY AND FRIDAY. WITH THE FRONTAL BOUNDARY STILL STALLED TO OUR SOUTH AND EAST AND NOT MUCH INSTABILITY FORECAST OVER OUR AREA, KEPT THUNDERSTORMS OUT OF THE FORECAST AREA. A COLD FRONT IS EXPECTED TO APPROACH FROM THE NORTH FRIDAY. TODAY`S 12Z MODEL GUIDANCE CONTINUES TO SHOW THE PROGRESSION OF THIS BOUNDARY SLOWING DOWN AS IT PUSHES THROUGH OUR AREA FRIDAY NIGHT AND SATURDAY MORNING DUE TO WEAKER STEERING FLOW ALOFT THIS FAR SOUTH. SCATTERED SHOWERS ARE EXPECTED WITH THE FROPA. EASTERLY LOW- LEVEL IS THEN FORECAST TO DEVELOP LATER ON SATURDAY IN RESPONSE TO HIGH PRESSURE BUILDING INTO SOUTHEASTERN CANADA. THE BOUNDARY SHOULD BASICALLY WASH OUT ONCE THE ONSHORE FLOW TAKES OVER. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WIDESPREAD IFR CONDITIONS ACROSS THE TERMINALS. ONCE IN A WHILE SOME MVFR CONDITIONS OCCUR AS THE SHOWERS WILL MIX OUT SOME OF THE LOWER CIGS FOR A TIME. THE TREND FOR MOSTLY IFR (CIGS) WILL CONTINUE OVERNIGHT AND THE GUIDANCE OFFERS LITTLE HOPE THAT THINGS WILL CHANGE OVERNIGHT INTO TUE MORNING. WE WILL GO ALONG WITH THAT FOR NOW AND TAPER OFF THE STEADY PRECIP FIRST ACROSS THE NORTH/WEST THEN GRADUALLY FURTHER SOUTH/EAST OVERNIGHT. TSTMS POSSIBLE KILG-KMIV-KACY...MAYBE A FEW RUMBLES THRU 02Z AT KPHL. OUTLOOK... TUESDAY NIGHT THROUGH SATURDAY...MARINE LAYER WILL BE ESTABLISHED WITH PERSISTENT EAST TO NORTHEAST FLOW THROUGH MOST OF THE PERIOD. THIS WILL LEAD TO PERIODS OF LOW CLOUDS AND MVFR/IFR CIGS, ESPECIALLY AT NIGHT AND MORNING. LOW CLOUDS WILL LIKELY BE MORE DIFFICULT TO MIX OUT AT ACY AND OTHER LOCATIONS NEAR THE COAST. CANNOT RULE OUT A FEW SHOWERS EACH DAY BUT A CHANCES FOR SHOWERS MAY BE ENHANCED SLIGHTLY LATE FRIDAY-EARLY SATURDAY WHEN A COLD FRONT PASSES THROUGH. && .MARINE... WE HAVE DECIDED TO ISSUE A SCA FOR ALL OF THE WATERS THIS EVENING WITH MANY OF THE WIND OBSERVATION SITES REPORTING GUSTS TO/OVER 25 KNOTS AT TIMES. A BATCH OF TSTMS APPROACHING FROM THE SW WILL IMPACT THE WATERS FURTHER WITH HAZARDOUS CONDITIONS. STAY TUNED FOR MAINE STATEMENTS AND POSSIBLE SMW`S OVER THE NEXT FEW HOURS. OUTLOOK... TUESDAY NIGHT THROUGH THURSDAY...EAST TO NORTHEAST FLOW WILL PERSIST DURING THE MIDWEEK. WINDS WILL BE 15-20 KT BUT WITHOUT UNFAVORABLE MIXING PROFILES, CAPPED WIND GUSTS TO UNDER 25 KT. LATEST WAVEWATCH GUIDANCE SHOWS SEAS INCREASING TO 4-5 FT IN OUR COASTAL ATLANTIC WATERS TUESDAY NIGHT AND CONTINUING THROUGH THURSDAY. OPTED TO HOLD OFF ON A THIRD/FOURTH PERIOD SCA HEADLINE DUE TO THE UNCERTAINTY OF REACHING CRITERIA IN THIS MARGINAL SETUP. THURSDAY NIGHT THROUGH FRIDAY NIGHT...WINDS AND SEAS WILL BE BELOW SCA THRESHOLD. SATURDAY...ONSHORE FLOW STRENGTHENS. SEAS MAY BUILD TO ABOVE 5 FT DURING THE WEEKEND IN RESPONSE TO A STRONG LOW PRESSURE SYSTEM TRACKING WELL TO OUR EAST. && .RIP CURRENTS... THERE IS A MODERATE RISK OF RIP CURRENTS ALONG THE NEW JERSEY SHORE AND DELAWARE BEACHES THIS AFTERNOON AND EVENING. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLASH FLOOD WATCH UNTIL 6 AM EDT TUESDAY FOR PAZ070-071- 101>106. NJ...FLASH FLOOD WATCH UNTIL 6 AM EDT TUESDAY FOR NJZ008>010- 012>027. DE...FLASH FLOOD WATCH UNTIL 6 AM EDT TUESDAY FOR DEZ001>004. MD...FLASH FLOOD WATCH UNTIL 6 AM EDT TUESDAY FOR MDZ008-012-015- 019-020. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ430-431- 450>455. && $$ SYNOPSIS...KLEIN NEAR TERM...GAINES SHORT TERM...GAINES LONG TERM...KLEIN AVIATION...GAINES/KLEIN MARINE...GAINES/KLEIN RIP CURRENTS...

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