Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 191930 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 330 PM EDT SAT APR 19 2014 .SYNOPSIS...
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LARGE HIGH PRESSURE CENTERED OVER WESTERN QUEBEC THIS AFTERNOON WILL BUILD SOUTHEASTWARD. THE HIGH SHOULD CONTINUE TO INFLUENCE OUR REGION INTO MONDAY NIGHT. A COLD FRONT IS FORECAST TO APPROACH FROM THE WEST AND IT SHOULD PASS THROUGH OUR REGION LATE ON TUESDAY. HIGH PRESSURE IS EXPECTED TO FOLLOW FOR WEDNESDAY INTO FRIDAY. LOW PRESSURE AND A COLD FRONT FROM THE WEST ARE ANTICIPATED TO ARRIVE ON SATURDAY.
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&& .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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THE GFS INITIALIZATION LOOKED BETTER AT 925MB, THE WRF-NMMB BETTER AT 850MB AND BOTH ABOUT THE SAME AT 500MB OFF THE 12Z SOUNDINGS. BUT ONCE AGAIN THROUGH THE SHORT TERM MODEL DIFFERENCES ARE NOT LARGE ENOUGH TO GIVE CONFLICTING GUIDANCE. A QUIET NIGHT TONIGHT WITH MAYBE SOME CIRRUS DURING THE EVENING, OTHERWISE CLEAR SKIES. BIGGEST FORECAST PROBLEM ARE MINIMUM TEMPERATURES AS WE HAVE CONFLICTING FORCES. AS THE NIGHT PROGRESSES, THE WINDS ABOVE THE BOUNDARY LAYER ARE FORECAST TO INCREASE. THE PREDICTED SPEEDS ARE CLOSE TO THE 50/50 THRESHOLD OF SURFACE MIXING. OUR CONCLUSION WAS TO GIVE THE GRADIENT SOME DUE EAST OF I95 WHERE OUR MINS ARE PREDICTED TO OCCUR EARLIER AND THEN OVERALL HIGHER THAN STAT GUIDANCE. NW OF I95 AND THE FALL LINE THE RADIATIONAL COOLING INVERSION MIGHT BE TOO MUCH TO OVERCOME AND WE WENT CLOSER TO STAT GUIDANCE. DEW POINTS ARE SO LOW ITS GOING TO BE TOUGH FOR FROST TO OCCUR ANYWHERE. THE MORE LIKELY PLACES ARE LOCALES WHERE THE GROWING SEASON HAS NOT BEEN DECLARED STARTED, SO NO MENTION IN THE GRIDS/ZONES OR HEADLINES.
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
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A SUNNY DAY IS IN STORE AS HIGH PRESSURE BUILDS INTO NEW ENGLAND. THE ASSOCIATED AIR MASS IS OH SO DRY (NO SC OVER THE OCEAN YET) THAT THE ONSHORE FLOW SHOULD NOT PRODUCE LITTLE IF ANY CLOUDINESS. THE ONSHORE FLOW SHOULD KEEP LOCATIONS NEAR THE COAST AND WEST OF DELAWARE BAY COOLER THAN TODAY. THE LATE APRIL SUN THOUGH FINDS A WAY TO OUTPERFORM, ESPECIALLY WITH THE TREES WELL BEHIND SCHEDULE. WE WENT AT OR ABOVE STAT GUIDANCE FROM AROUND I95 AND DE STATE 1 WESTWARD AND NORTHWESTWARD. WE WENT CLOSER TO STAT GUIDANCE EAST OF THESE ROADWAYS. EVEN WITHOUT THE ONSHORE FLOW, THE ANTECEDENT AIR MASS IS PREDICTED TO BE RELATIVELY MILDER IN THE NWRN PART OF OUR CWA. WE ARE GOING TO BE SWITCHING THE STRONGER WINDS ON SUNDAY VS TODAY AS THE WINDIEST LOCATIONS WILL BE IN EASTERN NJ AND DELAWARE WITH ABOUT THE SAME OR LESS WIND SPEEDS (DIRECTION EAST VS NORTH) IN PLACES FARTHER TO THE WEST.
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&& .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
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A RIDGE OF HIGH PRESSURE IS FORECAST TO REMAIN OVER OUR REGION FOR SUNDAY NIGHT INTO MONDAY NIGHT AS LOW PRESSURE OFF THE SOUTHEAST COAST MOVES FARTHER OUT TO SEA. A MAINLY CLEAR SKY IS ANTICIPATED FOR SUNDAY NIGHT AND MONDAY WITH PERHAPS AN INCREASE IN HIGH CLOUDS FROM THE WEST ON MONDAY NIGHT. TEMPERATURES ARE EXPECTED TO DROP INTO THE LOWER AND MIDDLE 30S ACROSS OUR NORTHERN COUNTIES LATE ON SUNDAY NIGHT WHERE WE ARE NOT YET ISSUING FROST AND FREEZE PRODUCTS. MINIMUM TEMPERATURES IN OUR CENTRAL AND SOUTHERN COUNTIES SHOULD BE MAINLY IN THE 35 TO 40 DEGREE RANGE. SPOTTY FROST IS POSSIBLE BUT IT DOES NOT SEEM AS THOUGH IT WILL BE WIDESPREAD ENOUGH TO WARRANT A MENTION AT THIS POINT. READINGS SHOULD RECOVER NICELY ON MONDAY WITH PLENTY OF SUNSHINE. HIGHS ON MONDAY AFTERNOON ARE FORECAST TO BE WELL INTO THE 60S AT MOST LOCATIONS. THE AXIS OF A MID LEVEL TROUGH IS EXPECTED TO PASS OVERHEAD ON WEDNESDAY MORNING. A SURFACE COLD ASSOCIATED WITH THE FEATURE SHOULD MOVE THROUGH OUR REGION LATE ON TUESDAY. WE HAVE MAINTAINED THE MENTION OF SHOWERS, MAINLY FOR TUESDAY AFTERNOON AND TUESDAY EVENING. PRECIPITATION TOTALS WILL LIKELY BE LESS THAN A QUARTER INCH IN OUR FORECAST AREA. THE MID LEVEL PATTERN SHOULD REMAIN PROGRESS WITH A RIDGE AXIS PASSING OVERHEAD ON FRIDAY. SURFACE HIGH PRESSURE FROM THE WEST IS ANTICIPATED TO MOVE ACROSS OUR REGION DURING THE SECOND HALF OF THE WORK WEEK BRINGING DRY WEATHER AND SEASONABLE TEMPERATURES. SURFACE LOW PRESSURE IS FORECAST TO PASS ACROSS THE GREAT LAKES ON FRIDAY AND FRIDAY NIGHT AND INTO THE NORTHEAST ON SATURDAY. AS A RESULT, WE WILL CARRY A CHANCE OF SHOWERS FOR FRIDAY NIGHT AND SATURDAY.
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&& .AVIATION /20Z SATURDAY THROUGH THURSDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE 18Z TAFS CONTINUED VFR CONDITIONS. FOR THE REST THIS AFTERNOON JUST SOME CIRRUS CLOUDS WITH NORTH WINDS WILL AVERAGE 10 TO 15 KNOTS (PLEASE LOOK AT KACY AND KMIV NEXT PARAGRAPH). ANY GUSTINESS SHOULD BE 20 KNOTS OR LESS. FOR KACY AND KMIV AND AIRPORTS IN DELAWARE AND SE NJ, A SEA AND BAY BREEZE FRONT HAS FORMED. IT JUST WENT THROUGH KACY AND IS NEARING KMJX. IT WILL CONTINUE TO PROGRESS WWD TO APPROXIMATELY A KBLM-KNEL- HAMMONTON IN ATLC COUNTY-WESTERN CUMBERLAND NJ AND THRU KENT AND SUSSEX CTY DELAWARE LATE THIS AFTN AND EARLY THIS EVENING BEFORE DISSIPATING. WE HAVE AN EAST WIND SHIFT TIME MENTIONED AT THOSE TERMINALS. TONIGHT NORTHEAST WINDS ABOUT 5 TO 10 KNOTS UNDER CLEAR SKIES (MAYBE SOME CIRRUS) AND NO VSBY RESTRICTIONS. ON SUNDAY CLEAR SKIES CONTINUING. WINDS WILL BE EAST AVERAGING AROUND 10 KNOTS WITH GUSTINESS TO AROUND 20 KTS AT KMIV AND KACY AS WELL AS OTHER NEAR THE COAST AIRPORTS. THERE IS A POCKET OF STRONGER WINDS PASSING ALOFT ON SUNDAY MORNING. A BRIEF ONE OR TWO HOUR PERIOD OF GUSTINESS IS POSSIBLE AT THE KPHL AREA AIRPORTS. OUTLOOK... SUNDAY NIGHT THROUGH MONDAY NIGHT...MAINLY VFR. TUESDAY AND TUESDAY NIGHT...MAINLY VFR WITH A CHANCE OF AFTERNOON AND EVENING SHOWERS. WEDNESDAY THROUGH THURSDAY...MAINLY VFR.
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&& .MARINE...
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THE SMALL CRAFT ADVISORY CONTINUES FOR THE OCEAN WATERS THROUGH THE DAY ON SUNDAY. SEAS AT BUOY 9 ARE STILL AT 5 FEET, SO AT LEAST FOR THE SOUTHERN WATERS, THE GAP OF NON-SMALL CRAFT ADVISORY WINDS IS GETTING SMALLER ALL THE TIME. THE GUIDANCE HAS BEEN TOO LOW WITH SWELLS LATELY. WE ARE GOING TO BE ADDING DELAWARE BAY TO THE SMALL CRAFT ADVISORY FOR SUNDAY DAY. WE HAVE HIGHER CONFIDENCE ABOUT THE WIND CRITERIA BEING MET IN THE LOWER BAY THAN THE UPPER BAY. REGARDLESS, WINDS SHOULD START DIMINISHING DURING SUNDAY AFTERNOON AND MIGHT FALL BELOW SMALL CRAFT ADVISORY CRITERIA ALONG THE MONMOUTH COUNTY ATLANTIC WATERS AND ALL OF DELAWARE BAY BY THE END OF THE DAY. SEAS ON THE OCEAN WILL TAKE LONGER TO SUBSIDE BELOW SMALL CRAFT ADVISORY CRITERIA. OUTLOOK... SUNDAY NIGHT...A SMALL CRAFT ADVISORY IS IN EFFECT FOR OUR OCEAN WATERS FROM MANASQUAN INLET SOUTHWARD MAINLY FOR SEAS IN THE PERSISTENT NORTHEAST FLOW. MONDAY...WAVE HEIGHTS MAY REMAIN NEAR 5 FEET INTO MONDAY ON OUR OCEAN WATERS MAINLY FROM ATLANTIC CITY SOUTHWARD. MONDAY NIGHT THROUGH WEDNESDAY...NO MARINE HEADLINES ARE ANTICIPATED. WEDNESDAY NIGHT...NORTHWESTERLY WIND GUSTS AROUND 25 KNOTS ARE POSSIBLE. THURSDAY...NO MARINE HEADLINES ARE ANTICIPATED.
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&& .FIRE WEATHER...
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WE ARE GOING TO FLIP OUR FIRE WEATHER CONCERN ON SUNDAY TO THE NJ PINE BARRENS AS THEY WILL COME CLOSEST TO THE CONFLUENCE OF STRONG WIND GUSTS, LOW AFTERNOON RELATIVE HUMIDITY LEVELS AND CONTINUED DRY AND DRYING FINE FUELS. CLOSER TO THE IMMEDIATE COAST, THE RELATIVE HUMIDITY LEVELS SHOULD NOT BE REACHED. ELSEWHERE, WIND GUSTS OVERALL ARE EXPECTED TO REMAIN BELOW 20 MPH ON SUNDAY AFTERNOON. ON MONDAY WINDS ARE EXPECTED TO BE LIGHTER IN ALL AREAS AND RELATIVE HUMIDITY LEVELS MIGHT NOT DROP BELOW 30 PERCENT,
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&& .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ451>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR ANZ450. SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT SUNDAY FOR ANZ430- 431.
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&& $$ SYNOPSIS...IOVINO NEAR TERM...GIGI SHORT TERM...GIGI LONG TERM...IOVINO AVIATION...GIGI/IOVINO MARINE...GIGI/IOVINO FIRE WEATHER...GIGI

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