Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 250808 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 408 AM EDT SAT OCT 25 2014 .SYNOPSIS...
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A COLD FRONT OVER THE MIDWEST THIS MORNING WILL MOVE EASTWARD TODAY AND THROUGH THE AREA TONIGHT. THE MID-ATLANTIC REGION WILL BE SITUATED BETWEEN LOW PRESSURE OVER EASTERN CANADA AND HIGH PRESSURE BUILDING IN FROM THE TENNESSEE VALLEY ON SUNDAY. HIGH PRESSURE RIDGES INTO THE AREA SUNDAY NIGHT AND MONDAY. A WARM FRONT WILL LIFT NORTH OF THE AREA TUESDAY BEFORE A COLD FRONT MOVES THROUGH LATE WEDNESDAY. HIGH PRESSURE BRIEFLY RETURNS THURSDAY. LOW PRESSURE MAY DEVELOP OVER THE EASTERN UNITED STATES FRIDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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SURFACE RIDGE AXIS WILL BE MOVING OVERHEAD LATE THIS MORNING. LIGHT AND VARIABLE FLOW WILL BECOME MORE WESTERLY BY THE AFTERNOON WITH A TIGHTENING SURFACE PRESSURE GRADIENT. AMPLE SUNSHINE WILL ALLOW FOR DECENT VERTICAL MIXING TODAY, THOUGH NOT AS STRONG AS IN PAST DAYS...GUSTS UPWARDS OF 20 MPH ARE POSSIBLE THIS AFTERNOON. A DECK OF STRATOCU IS POSSIBLE BUT GIVEN THE LACK OF MOISTURE AND JUST REACHING CONVECTIVE TEMPERATURES NOT EXPECTING ANYTHING WIDESPREAD OR THICK. TEMPERATURES LOOK TO HAVE ANOTHER CHANCE TO CLIP 70F ACROSS THE SOUTHERN HALF OF THE CWA. THE WESTERLY DOWNSLOPING WINDS AND 925MB TEMPERATURES CLIMBING TO AROUND 12C WILL MAKE THIS POSSIBLE. WENT A COUPLE DEGREES ABOVE GUIDANCE FOR TODAY GIVEN THE ABOVE.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
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GUSTS SHOULD DROP OFF BY LATER THIS EVENING AND WINDS BACK TOWARDS THE SOUTHWEST JUST A BIT AHEAD OF AN APPROACHING WEAK COLD FRONT. THE FRONT SHOULD BLAST THROUGH THE REGION BY SUNDAY MORNING WITH JUST A FEW PASSING CLOUDS EXPECTED. THE COLUMN WILL REMAIN DRY ENOUGH AND THERE IS NOT MUCH FORCING ASSOCIATED WITH THE FRONT OVER OUR REGION, SO WE KEEP IT DRY. GOOD COLD AIR ADVECTION ALOFT WILL ALLOW FOR BETTER MIXING TONIGHT AND COUPLED WITH THE TIGHTER PRESSURE GRADIENT WE KEEP STRONGER WESTERLY WINDS THROUGH THE OVERNIGHT HOURS. WITH THAT BEING SAID, USED THE WARMER MAV GUIDANCE FOR LOWS TONIGHT.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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A VERTICALLY-STACKED LOW WILL BE POSITIONED OVER EASTERN CANADA WHILE HIGH PRESSURE IS CENTERED JUST WEST OF THE CENTRAL APPALACHIANS. A TIGHT PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS WILL RESIDE OVER THE MID-ATLANTIC REGION, THUS SUNDAY WILL BE A BREEZY DAY. 00Z NAM/GFS BUFKIT SOUNDINGS SHOW THE POTENTIAL FOR FREQUENT GUSTS 25 TO 30 MPH WITH OCCASIONALLY HIGHER GUSTS TO 35 MPH. POST-FRONTAL CAA EXPECTED TO BE TRANSIENT, BECOMING NEUTRAL DURING THE AFTERNOON. THEREFORE, TEMPS SHOULD BE ABLE TO REACH CLIMO (MID 60S) IN MOST PLACES. THE PRESSURE GRADIENT WILL WEAKEN SUNDAY NIGHT AS THE LOW LIFTS INTO THE CANADIAN MARITIME WHILE HIGH PRESSURE BUILDS TOWARD THE MIDDLE ATLANTIC. STILL NOT CERTAIN ON FULL DECOUPLING, SO WENT CONSERVATIVE WITH MIN TEMPS IN THE MID/UPPER 30S NORTHEAST PA/NORTHWEST NJ AND LOW/MID 40S FROM I-95 EAST. HIGH PRESSURE SHIFTS OFF THE SOUTHEAST COAST EARLY IN THE WEEK. SOUTH-SOUTHWEST RETURN FLOW AROUND THE HIGH ON LATE MONDAY WILL STRENGTHEN TUESDAY AS A WARM FRONT ADVANCES NORTHWARD THRU THE REGION AND A COLD FRONT APPROACHES FROM THE MIDWEST STATES. TUESDAY AND WEDNESDAY LOOKS TO BE THE WARMEST DAYS OF THE PERIOD (MAX TEMPS NEAR 70F) WITH THE WARM SECTOR ESTABLISHED IN THE REGION. LOW PRESSURE WILL CUT WELL TO OUR NORTHWEST AS IT TRACKS FROM THE GREAT LAKES TOWARD HUDSON BAY MIDWEEK. THE ATTENDANT COLD FRONT WILL PROGRESS INTO THE AREA DURING THIS TIME. DIFFERENCES IN TIMING OF FROPA HAVE NARROWED WITH THE LATEST MODEL GUIDANCE. THE COLD FRONT WILL MOST LIKELY MOVE THRU WEDNESDAY AFTERNOON INTO WEDNESDAY EVE. SHOWERS ARE POSSIBLE WITH THE FRONT. WENT SLIGHTLY HIGHER WITH POPS THAN PREVIOUS FORECAST BUT STILL LIMITED TO AROUND 30 PERCENT WITH LIMIT MOISTURE/LIFT ALONG THE FRONT. DRY CONDITIONS AND SEASONABLE TEMPS EXPECTED BEHIND THE FRONT THURSDAY WITH WEAK HIGH PRESSURE BUILDING IN FROM THE TN VALLEY. THE DETAILS FOR THE END OF THE WEEK STILL NEED TO BE DETERMINED BUT MODELS SIGNALING TOWARD THE AMPLIFICATION OF A LONGWAVE TROUGH OVER THE EASTERN CONUS ON FRIDAY. INCREASING CLOUDS ARE LIKELY WITH PERHAPS SHOWERS RETURNING TO OUR AREA.
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&& .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY - TONIGHT...VFR. WESTERLY WINDS GUSTING TO 20 KNOTS THIS AFTERNOON DECREASE THIS EVENING. WINDS BACK TOWARDS THE SOUTHWEST AHEAD OF APPROACHING DRY COLD FRONT. WINDS VEER TO THE WEST AGAIN BEHIND THE FRONT. HIGH CONFIDENCE. OUTLOOK... SUNDAY...VFR. BREEZY W-NW WINDS 15-20 KT WILL GUST UP TO 30 KT. SUNDAY NIGHT THROUGH TUESDAY NIGHT...VFR. LIGHT NW WINDS GENERALLY AOB 10 KT THRU MONDAY, BECOMING SLY TUESDAY. WEDNESDAY AND WEDNESDAY NIGHT...GENERALLY VFR ALTHOUGH A BRIEF PERIOD OF MVFR AND SHRA POSSIBLE WITH COLD FROPA.
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&& .MARINE...
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TODAY...SUB-SCA EXPECTED. GUSTS ACROSS OUR SOUTHERN WATERS MAY COME CLOSE TO SCA THIS MORNING BUT DROP OFF THROUGH THE DAY. SEAS WILL REMAIN 3 TO 4 FEET AND DECREASE BY THIS EVENING. HIGH CONFIDENCE. TONIGHT...SCA CONDITIONS EXPECTED, POSSIBLE BRIEF GALES RIGHT BEHIND COLD FRONT PASSAGE...MAINLY SOUTHERN WATERS. WESTERLY WINDS INCREASE TO 20 TO 25 KNOTS LATER TONIGHT AS A COLD FRONT MOVES THROUGH THE WATERS. THERE IS A LOW-END CHANCE OF A FEW GALE GUSTS BUT NOT CONFIDENT...HIGH END SCA GUSTS EXPECTED. HIGH CONFIDENCE ON SCA, LOW ON GALES. OUTLOOK... SUNDAY AND SUNDAY NIGHT...HIGH END SCA SUNDAY WITH W-NW GUSTING TO 30 KT. STILL CANNOT RULE OUT THE POSSIBILITY FOR GALES BUT SETUP NOT PARTICULARLY FAVORABLE FOR DEEP MIXING AS CAA ALOFT CEASES RATHER QUICKLY IN THE MORNING. SCA EXTENDED INTO SUNDAY EVE FOR THE WATERS, ENDING SOUTH TO NORTH OVERNIGHT FOR THE COASTAL ATLANTIC ZONES AS THE PRESSURE GRADIENT GRADUALLY WEAKENS. MONDAY AND MONDAY NIGHT...LIGHT WINDS AND CALM SEAS. TUESDAY AND WEDNESDAY...SOUTHWEST WINDS INCREASE AHEAD OF A COLD FRONT. HAVE CAPPED GUSTS AT 20 KT OWING TO STABLE MIXING PROFILES.
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&& .FIRE WEATHER...
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BREEZY AND DRY CONDITIONS EXPECTED ON SUNDAY BEHIND A COLD FRONT. SUSTAINED NW WINDS NEAR 20 MPH ARE EXPECTED. 00Z NAM/GFS BUFKIT SOUNDINGS SHOW THE POTENTIAL FOR FREQUENT GUSTS OF 25 TO 30 MPH WITH OCCASIONALLY HIGHER GUSTS TO 35 MPH. THE POST-FRONTAL CAA PATTERN IS BRIEF, BECOMING NEUTRAL DURING THE AFTERNOON. CURRENT FORECAST REFLECTS MIN RHS SUNDAY AFTERNOON IN THE LOW TO MID 30S EVEN AFTER LEANING TOWARD A DRIER (I.E., LOWER DEWPOINTS) SOLUTION WITH DOWNSLOPING W-NW FLOW OFF THE HIGHER TERRAIN. ADDITIONALLY, HEATING MAY BE LIMITED SOMEWHAT BY STRATOCU OFF THE GREAT LAKES, ESPECIALLY OVER THE NORTHWEST HALF OF THE CWA WHICH MAY PREVENT RHS FROM FALLING CRITICAL THRESHOLDS. AN ENHANCED THREAT FOR THE SPREAD OF WILDFIRES MAY EXIST ON SUNDAY WITH THE ABOVE METEOROLOGICAL FACTORS AND WITH FORECAST FUEL MOISTURE BELOW 10 PERCENT BUT CONFIDENCE NOT NEARLY HIGH ENOUGH TO ISSUE A FIRE WEATHER WATCH.
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&& .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 2 AM EDT MONDAY FOR ANZ452>455. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT MONDAY FOR ANZ450-451. SMALL CRAFT ADVISORY FROM 8 AM TO 9 PM EDT SUNDAY FOR ANZ430- 431.
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&& $$ SYNOPSIS...KLEIN NEAR TERM...HEAVENER SHORT TERM...HEAVENER LONG TERM...KLEIN AVIATION...HEAVENER/KLEIN MARINE...HEAVENER/KLEIN FIRE WEATHER...KLEIN

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