Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 291751 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 151 PM EDT WED OCT 29 2014 .SYNOPSIS...
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A COLD FRONT CROSSING THE MID ATLANTIC COAST EARLY THIS AFTERNOON TRAILS INTO WEAK LOW PRESSURE OVER SOUTHEAST VIRGINIA. THE COLD FRONT AND LOW PRESSURE WILL MOVE OFFSHORE TONIGHT. HIGH PRESSURE WILL BRIEFLY AFFECT THE AREA THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE GREAT LAKES REGION AND SOUTH OF THE AREA ON FRIDAY, BEFORE COMBINING WITH A DEVELOPING AND STRENGTHENING COASTAL LOW OFFSHORE OF THE MID ATLANTIC COAST SATURDAY. THIS LOW WILL MOVE WELL NORTHEAST OF THE AREA ON SUNDAY, THEN HIGH PRESSURE IS EXPECTED TO BUILD BACK ACROSS THE EAST COAST MONDAY, THEN OFFSHORE TUESDAY AHEAD OF AN APPROACHING FRONTAL SYSTEM.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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MOUNT HOLLY IS ALSO SERVICE BACKING UP STERLING THROUGH 4 PM TODAY. YOU`LL SEE STERLING FORECAST PRODUCTS ISSUED BY NWS MOUNT HOLLY. 1230 PM ESTF: LOWERED TEMPS AS A PROCESS FROM WEST TO EAST THIS AFTN AFTER RAIN DEVELOPS. USED A 50 50 BLEND OF THE NEW 12Z/29 GFS/NAM MOS TEMPS. THERE STILL WILL BE ERRORS BUT TEMPS ARE NOTABLY COOLER DURING MID AND LATE AFTN PER EXPECTED/MODELED RAIN. EXPECTING A 2-4 HOUR WIDE BAND OF MEASURABLE SHOWERS. MAX AMT .4 INCHES IN PWAT OF 1.1 INCHES...HEAVIEST NEAR I-95. DID NOT INCLUDE ISOLATED THUNDER POTENTIAL VCNTY FENWICK ISLAND DE LATE TODAY BUT ITS MODELED. THE CURRENT HOURLY TEMPS OVER E PA AND NE MD IN RAIN COOLING THE AIR TEMP (WET BULBING) MAY STILL BE 2 DEGREES TOO WARM IN EASTERN PA DURING MID LATE AFTN (NEAR 52 DEGREES INSTEAD OF THE HOURLY MID 50S TEMPS AS POSTED AT 1230 PM). DID NOTICE 1.5 MI MDT TO HEAVY RAIN AT IAD IN THE PAST HOUR. A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD FROM COASTAL NJ AND DE AT 17Z. IT TRAILS INTO LOW PRES OVER SE VA WHICH IS A RESPONSE TO PROCESSES ALOFT THAT WAS GENERATING THE BAND OF RAIN FROM WESTERN VA INTO E PA NEWD. RAINFALL AMOUNTS WILL BE LIGHT (GENERALLY UNDER ONE THIRD INCH). ISOLATED SLIGHTLY HIGHER AMOUNTS POSSIBLE LATE THIS AFTERNOON AS A WEAK DISTURBANCE TRAILING THE FRONT IS FORECAST TO TRACKS FROM VA TO THE DELMARVA, LEADING TO AN ENHANCEMENT OF PRECIP OVER THE SOMEWHERE OVER THE SOUTHEASTERN TWO THIRDS OF THE CWA.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... THE COLD FRONT WILL CONTINUE TO MOVE OFF THE EAST COAST TONIGHT. THE BACK EDGE OF THE LINGERING SHOWERS BEHIND THE BOUNDARY SHOULD BE SHIFTING THRU THE I-95 CORRIDOR EARLY THIS EVENING AND OFF THE NJ/DE COAST AROUND MIDNIGHT. WEST-NORTHWEST WINDS BEHIND THE FRONT WILL ADVECT COLDER AND EVENTUALLY DRIER AIR INTO THE REGION. SKIES WILL CLEAR NOT TOO LONG AFTER PRECIP ENDS- DURING THE EVENING ACROSS EASTERN PA AND NORTHWEST NJ AND OVERNIGHT FOR COASTAL AREAS. THE PRESSURE GRADIENT WILL BE STRONG ENOUGH FOR A 5-10 MPH WIND TO CONTINUE OVERNIGHT ESPECIALLY WITH CAA AIDING IN A MIXED NOCTURNAL BOUNDARY LAYER. THEREFORE, WENT A COUPLE OF DEGREES ABOVE A MAV/MET BLEND FOR MIN TEMPS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGH PRESSURE IS EXPECTED TO BRIEFLY AFFECT THE AREA THURSDAY INTO THURSDAY NIGHT. DRY WEATHER AND NEAR NORMAL TEMPERATURES ARE EXPECTED BEFORE A DECLINE IN THE WEATHER FOR THE UPCOMING WEEKEND. ON FRIDAY, AN AREA OF LOW PRESSURE WILL BE MOVING OUT OF THE GREAT LAKES REGION, AND IS EXPECTED TO MOVE TO THE SOUTH OF THE AREA WHILE A COASTAL LOW DEVELOPS AND STRENGTHENS TO OUR SOUTH. WE DO NOT EXPECT MUCH, IF ANY PRECIPITATION DURING THE DAY AS THE PRECIPITATION TIED TO THE SYSTEM TO OUR WEST SHOULD REMAIN TO OUR NORTH AND WEST UNDERNEATH THE MID/UPPER LOW/TROUGH. AS WE GO INTO FRIDAY NIGHT, THE MID/UPPER LOW WILL SWING TO OUR SOUTH, WHILE THE SURFACE LOW WILL BEGIN GETTING ABSORBED BY THE COASTAL LOW. THIS WILL ALLOW SOME LIGHT PRECIPITATION TO FILL IN ACROSS THE AREA AS THE MAJORITY OF THE MODEL GUIDANCE IS INDICATING. IT LOOKS LIKE ANY PRECIPITATION THAT STARTS OUT FRIDAY NIGHT SHOULD BE MOSTLY A COLD RAIN AS MODELS NOW KEEP 925/850 MB TEMPS ABOVE FREEZING, ALTHOUGH IT IS STILL POSSIBLE FOR A MIXTURE ACROSS THE FAR NORTHERN AREAS. THE MID/UPPER TROUGH WILL SWING OFFSHORE OF THE NORTH CAROLINA COAST SATURDAY, WHICH WILL ALLOW THE SURFACE LOW TO STRENGTHEN AND WRAP UP MORE. THE GFS KEEPS THE PRECIP CLOSE TO THE SURFACE AND MID-LEVEL LOW AND MOSTLY OFFSHORE, BUT THE ECMWF AND CANADIAN KEEP PRECIP ACROSS THE ENTIRE AREA AND EXTEND IT PRETTY FAR TO OUR NORTHWEST, SO WE WILL KEEP A CHANCE OF SHOWERS THROUGH THE DAY SATURDAY. THE MODELS DO SHOW THE PRECIP MOVING TO OUR NORTHEAST OVERNIGHT SATURDAY AS THE SURFACE AND MID/UPPER LOW PULL TO OUR NORTHEAST, SO WE`LL HAVE DECREASING POPS OVERNIGHT. THE MODELS KEEP THE SUB-FREEZING TEMPERATURES OUT OF THE AREA UNTIL OVERNIGHT SATURDAY, SO THE BEST CHANCE FOR A MIX OR COMPLETE CHANGE OVER TO SNOW WILL BE SATURDAY NIGHT INTO SUNDAY MORNING IF THERE IS STILL ANY REMAINING PRECIPITATION, MAINLY ACROSS THE NORTHERN THIRD OF THE AREA. WINDS WILL INCREASE SATURDAY INTO SATURDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS SIGNIFICANTLY BETWEEN THE COASTAL LOW AND HIGH PRESSURE TO THE WEST. WINDS LOOK TO GUST BETWEEN 30-40 MPH, WITH HIGHER GUSTS POSSIBLE CLOSER TO THE COAST. SUNDAY IS EXPECTED TO BE DRY, BUT COLD AND BLUSTERY AS A STIFF NORTHWEST FLOW IS EXPECTED AS THE LOW PRESSURE STRENGTHENS TO OUR NORTHEAST AND HIGH PRESSURE BEGINS APPROACHING FROM THE WEST. WINDS COULD CONTINUE TO GUST 30-40 MPH ACROSS THE AREA. HIGH PRESSURE IS EXPECTED TO BUILD TO OUR SOUTH MONDAY AND NOSE ITS WAY INTO OUR AREA. THIS WILL PROVIDE FAIR WEATHER WITH TEMPERATURES RISING BACK CLOSER TO NORMAL. ON TUESDAY, THE HIGH IS EXPECTED TO BUILD OFFSHORE OF THE SOUTHEAST COAST, WHILE A WARM FRONT LIFTS NORTH OF THE AREA AHEAD OF THE NEXT APPROACHING COLD FRONT. AS OF NOW, THE FORECAST FOR TUESDAY IS FOR DRY WEATHER WITH WARMING TEMPERATURES, ALTHOUGH IF THE WARM FRONT PASSES CLOSE ENOUGH, A FEW SHOWERS MAY BE POSSIBLE. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. FOR MOUNT HOLLY: REMAINDER OF THIS AFTERNOON...PREDOMINATELY VFR CIGS THIS AFTERNOON AOA 3500 FT. A BRIEF PERIOD OF MVFR CIGS/VSBYS IS POSSIBLE WITH HEAVIER SHRA BEHIND A COLD FRONT AND CONFIDENCE HAS INCREASED SEEING THE 2500 FT DEVELOP OVER CENTRAL AND S NJ EARLY THIS AFTERNOON AND ALSO SEEING THE BRIEF 1MI HEAVY RAIN MVFR CIG AT KIAD SINCE 17Z. SHOWER BAND LASTS 2-4 HOURS ONCE IT STARTS. LATEST HIGH RES SHORT TERM GUIDANCE AND THE 12Z NAM ARE SUGGESTING SHOWERS MAY NOT ARRIVE KACY AND KMIV TIL AROUND 21-22Z AND MAY LINGER THROUGH 01Z THIS EVENING. LIGHT SHIFTING WIND TURNING W TO NW AND BRIEFLY GUSTING 22 KT (1 HOUR LESS) BEHIND THE COLD FRONTAL PASSAGE. TONIGHT...VFR CIGS CLEARING FROM WEST TO EAST WITH LEFTOVER RAIN KACY/KMIV AND SE DELAWARE ENDING BY 03Z/30. LIGHT NORTHWEST WIND. FCSTG POSSIBLE MVFR FOG AT KRDG/KABE/KMIV AFTER 05Z. FOR STERLING: NWS MOUNT HOLLY IS BACKING UP THIS OFFICE AND THEIR TAFS THROUGH 20Z TODAY. REMAINDER OF THIS AFTERNOON...PREDOMINANT VFR CIGS. A 2-4 HOUR WIDE BAND OF SHOWERS CROSSES THE AREA WITH BRIEF 1-3 MI RAIN AND MVFR CIGS IN THE HEAVIER SHOWERS. TONIGHT...VFR CLEARING WITH A LIGHT NW WIND. OUTLOOK... THURSDAY-FRIDAY...MOSTLY VFR. FRIDAY NIGHT-SATURDAY NIGHT...LOWER END VFR OR UPPER END MVFR WITH CIGS 2,500-3,500 EXPECTED. LOWER VSBYS POSSIBLE WITH RAIN SHOWERS. SNOW SHOWERS POSSIBLE ACROSS NORTHEAST PENNSYLVANIA AND NORTHWEST NEW JERSEY. GUSTY NORTH-NORTHWEST WINDS SATURDAY INTO SATURDAY NIGHT 25-30 KNOTS, POSSIBLY HIGHER NEAR THE COAST. SUNDAY...VFR. GUSTY NORTHWEST WINDS 25-30 KNOTS.
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&& .MARINE...
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44065 HAS RETURNED TO SVC. 44009 WINDS OTS AND WE DONT KNOW A SERVICE DATE FOR REPAIR YET. NO HEADLINES THROUGH TONIGHT. WIND WAS SHIFTING NW WITH A FEW GUSTS AROUND 20 KT THIS AFTERNOON. NW WIND TONIGHT AT 10 TO 15 KT. OUTLOOK... THURSDAY-FRIDAY NIGHT...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED, ALTHOUGH WINDS A SEAS WILL BE INCREASING LATE FRIDAY NIGHT. SATURDAY-SATURDAY NIGHT...INCREASING WINDS SATURDAY AND SATURDAY NIGHT AS A COASTAL LOW STRENGTHENS. GALE FORCE WINDS LOOKING MORE LIKELY. SUNDAY...GALE FORCE WINDS POSSIBLE EARLY, BEFORE DIMINISHING TO SMALL CRAFT ADVISORY LEVELS LATE IN THE DAY.
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&& .EQUIPMENT...
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SERVICE BACKUP FOR STERLING - LWX TODAY. HAVE LISTED THIS UNDER EQUIPMENT...JUST IN CASE THIS SERVICE BACKUP MESSAGE IS MISSED IN THE NEAR TERM AND AVIATION SECTION. 44065 BUOY HAS RETURNED TO SVC. 44009 WIND OTS AND NO SERVICE DATE FOR REPAIR AS YET.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG 150 SHORT TERM...KLEIN LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON 150 MARINE...DRAG/ROBERTSON 150 EQUIPMENT...150

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