Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 300751 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 351 AM EDT SAT AUG 30 2014 .SYNOPSIS...
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HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST WILL CONTINUE TO MOVE EAST TODAY AND TONIGHT. MEANWHILE...A WARM FRONT IS EXPECTED TO LIFT NORTH LATE SATURDAY, THEN BECOME NEARLY STATIONARY NEAR THE CANADIAN BORDER SUNDAY THROUGH TUESDAY. A COLD FRONT IS THEN EXPECTED TO MOVE ACROSS THE AREA TUESDAY NIGHT AND EARLY WEDNESDAY, FOLLOWED BY HIGH PRESSURE FOR THE REMAINDER OF THE WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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OUR WEATHER WILL BE IN TRANSITION TODAY AS AN UPPER-LEVEL RIDGE SLIDES ACROSS AND THEN SHIFTS TO OUR EAST. AS THIS OCCURS, SURFACE HIGH PRESSURE WILL CONTINUE TO RETREAT TO THE NORTHEAST. THIS OPENS THE DOOR FOR A SOUTHERLY FLOW THAT WILL BRING IN MORE MOISTURE. THE MODEL GUIDANCE SHOWS WAA OCCURRING THROUGH THE DAY, HOWEVER THERE IS A MORE NOTED INCREASE TOWARD LATE AFTERNOON. THIS ALSO OCCURS AS AN INCREASE IN THE MOISTURE ARRIVES, WHICH IS SEEN IN THE THETA-E FIELDS. THIS INCREASE IN MOISTURE WILL ALLOW THE SURFACE DEW POINTS TO INCREASE, ALTHOUGH THIS PROCESS DURING THE DAYLIGHT HOURS WILL PROBABLY BE GRADUAL FOR MUCH OF THE AREA. THE MOISTURE INCREASE SHOULD ALSO RESULT IN MORE CLOUDINESS THROUGH THE DAY WITH CUMULUS DEVELOPMENT BELOW SOME MID TO HIGH LEVEL CLOUDS ON THE WESTERN FLANK OF THE DEPARTING RIDGE. THIS INCREASE IN MOISTURE WITHIN THE SOUTHERLY FLOW IS ALREADY EVIDENT EARLY THIS MORNING WITH AREAS OF CLOUDINESS TRYING TO EXPAND NORTH-NORTHEASTWARD FROM VIRGINIA AND MARYLAND. THERE ARE ALSO SOME LOW CLOUDS ACROSS NORTHEASTERN PENNSYLVANIA DUE TO SOME WEAK UPSLOPE FLOW COMBINED WITH BOUNDARY LAYER COOLING. AT LEAST SOME FORECAST SOUNDINGS INDICATE A CAP IN PLACE AS WARMING OCCURS ALOFT DURING THE DAY, HOWEVER MOISTURE NEAR THE BASE OF THE CAP SHOULD HELP FOCUS SOME ADDITIONAL CLOUD DEVELOPMENT. LOW PRESSURE TRACKING ACROSS THE GREAT LAKES REGION AHEAD OF AN UPPER-LEVEL TROUGH WILL HELP ASSIST IN WAA DOWNSTREAM, WHICH WILL ORGANIZE A WARM FRONT TO OUR SOUTHWEST. IN ADDITION, CONVECTIVE DEVELOPMENT IS EXPECTED TO OUR WEST WITHIN THE DEVELOPING WARM SECTOR AND NEAR A PRE-FRONTAL TROUGH. HOWEVER, THE LIFT WITH THESE FEATURES ARE EXPECTED TO REMAIN TO OUR WEST AND THEREFORE TODAY WAS KEPT DRY. AS FOR HIGH TEMPERATURES, WE USED A BLEND OF THE NAM/GFS MOS THEN MADE A LITTLE BIT OF AN UPWARD ADJUSTMENT FOR SOME INLAND AREAS GIVEN THE WAA. WE ARE NOT ANTICIPATING TO OBTAIN DEEP MIXING AND THE SURFACE FLOW LOOKS MOSTLY FROM THE SOUTH OR SOUTHEAST. THIS WOULD TEND TO KEEP TEMPERATURES FROM INCREASING DRAMATICALLY, ALTHOUGH IT SHOULD BE WARMER THAN YESTERDAY WITH SOME ADDED HUMIDITY AS WELL.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
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HIGH PRESSURE AT THE SURFACE WILL BE SITUATED TO OUR EAST ALLOWING A SOUTHERLY FLOW TO BE MAINTAINED. OUR REGION WILL BECOME INCREASINGLY MORE ON THE NORTHWESTERN FLANK OF THE UPPER-LEVEL RIDGE, AND THE PASSAGE OF A WARM FRONT WILL ALLOW MUCH MORE HUMID AIR TO OVERSPREAD THE REGION. WE SHOULD SEE A DECENT INCREASE IN THE SURFACE DEW POINTS IN THE EVENING AS ANY MIXING DIMINISHES. WHILE WE STILL MAINTAIN SOME WAA THROUGH THE NIGHT, THIS GENERALLY TURNS WEAK. WE DO MAINTAIN SOME MOISTURE ADVECTION THOUGH, AND THIS COMBINED WITH A WARMER BOUNDARY LAYER MAY LEAD TO AREAS OF STRATUS AND EVEN SOME FOG. THE MAIN SHORT WAVE TROUGH THAT IS FORECAST TO BE AMPLIFYING ACROSS THE GREAT LAKES IS FORECAST TO HANG BACK FAIRLY FAR TO OUR WEST. THERE DOES APPEAR TO BE SOME LEAD SHORT WAVES TRACKING NORTHEASTWARD ALONG THE PERIPHERY OF THE UPPER-LEVEL RIDGE. THE FORECAST SOUNDINGS DO SHOW SOME INCREASE IN THE INSTABILITY TONIGHT, HOWEVER THERE MAY NOT BE MUCH FORCING. THERE COULD BE SOME WEAKENING SHOWERS/THUNDER APPROACHING OUR NORTHWEST ZONES THIS EVENING BEFORE THEY DISSIPATE, THEN PERHAPS SOME ADDITIONAL ACTIVITY MAY TRY AND ARRIVE ACROSS OUR WESTERN ZONES TOWARD DAYBREAK. THE LATTER MAY BE ASSOCIATED WITH AN EMBEDDED SHORT WAVE TRACKING AROUND THE RIDGE. OVERALL, WE THINK THE GREATER CHC WOULD BE TO OUR WEST CLOSER TO THE SHORT WAVE TROUGH AND ITS ASSOCIATED LIFT. THEREFORE ATTM, WE WERE SLOW TO INCREASE THE POPS TOWARD MORNING ACROSS THE WESTERN ZONES. OTHERWISE, AN INCREASE IN CLOUDS ESPECIALLY LATE WITH SOME STRATUS DEVELOPMENT AND PERHAPS PATCHY FOG. WE ARE NOT ALL THAT CERTAIN HOW MUCH FOG DEVELOPS GIVEN THE AIRMASS IS STILL UNDERGOING MOISTENING, THEREFORE WE DID NOT INCLUDE FOG ATTM. AS FOR LOW TEMPERATURES, WE WENT WITH AN INITIAL EVEN BLEND OF THE NAM/GFS MOS THEN MADE SOME MAINLY MINOR TWEAKS.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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MID-LEVEL RIDGING OVER THE EASTERN U.S. NEAR THE BEGINNING OF THE LONG TERM PERIOD GRADUALLY BECOMES ZONAL TOWARD THE END OF THE PERIOD WHICH TRANSLATES INTO ABOVE NORMAL TEMPERATURES FOR MUCH OF THE PERIOD. SUNDAY - TUESDAY...A NEARLY STATIONARY FRONTAL BOUNDARY TO OUR NORTH AND A SOUTHWESTERLY FLOW BOTH AT THE SURFACE AND ALOFT WILL PUMP IN WARM AND MOIST AIR OVER OUR REGION THROUGH THE PERIOD, BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE SUNDAY NIGHT INTO MONDAY. DEWPOINTS WILL RISE INTO THE 70S ACROSS THE REGION WHICH WILL BE INDICATIVE OF HIGHER THAN NORMAL PRECIPITABLE WATER VALUES...POSSIBLY OVER TWO INCHES. GIVEN THE DRY CONDITIONS OF LATE, ANY FLOODING THAT DOES DEVELOP WOULD MOST LIKELY BE URBAN AND POOR DRAINAGE TYPE FLOODING. WITH TEMPERATURES A GOOD TEN DEGREES ABOVE NORMAL, AND DEWPOINT TEMPERATURES IN THE 70S, IT WILL FEEL LIKE THE DOG DAYS OF SUMMER. WEDNESDAY...LOW PRESSURE SYSTEM WELL TO THE NORTH OF THE REGION SENDS A SOMEWHAT STRONGER COLD FRONT THROUGH OUR AREA. THEN CONDITIONS WILL DRY OUT BEHIND THIS FRONT AS HIGH PRESSURE BUILDS IN FROM THE WEST DURING THE DAY. DEWPOINTS ARE EXPECTED TO DROP IN TO THE MID 60S, AND TEMPERATURES SHOULD DROP A FEW DEGREES TOO, ALTHOUGH THEY ARE STILL EXPECTED TO BE ABOVE NORMAL FOR THIS TIME OF YEAR. THURSDAY - FRIDAY...HIGH PRESSURE CONTINUES TO BUILD BACK INTO OUR REGION WITH ZONAL FLOW ALOFT, AND WE SHOULD BE DRY BOTH DAYS. TEMPERATURES MAY DROP A DEGREE OR TWO COMPARED TO WEDNESDAY, BUT STILL SHOULD BE A LITTLE ABOVE NORMAL.
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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...LOCALIZED EARLY MORNING GROUND FOG, OTHERWISE VFR WITH SCATTERED TO BROKEN BASES AROUND 5000 FEET. SOME STRATUS EARLY THIS MORNING MAINLY NORTH OF KABE. SOUTHERLY WINDS INCREASING TO AROUND 10 KNOTS. TONIGHT...VFR FOR AWHILE, HOWEVER AN INCREASE IN MOISTURE SHOULD RESULT IN AREAS OF STRATUS AND/OR FOG TOWARD MORNING. SOUTH-SOUTHWEST WINDS 5 KNOTS OR LESS. OUTLOOK... SUNDAY...VFR EARLY. THEN MVFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS...ESPECIALLY NORTH AND WEST OF PHL. MDT CONFIDENCE. SUNDAY NIGHT INTO MONDAY...IFR CONDITIONS POSSIBLE WITH SHOWERS AND THUNDERSTORMS. CONDITIONS IMPROVING TO VFR LATER MONDAY. LOW TO MDT CONFIDENCE ON PRECIP COVERAGE. MONDAY NIGHT AND TUESDAY...GENERALLY VFR CONDITIONS EXPECTED. TUESDAY NIGHT INTO WEDNESDAY...MVFR CONDITIONS POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS. LOW TO MDT CONFIDENCE. LATE WEDNESDAY AND THURSDAY...VFR. MDT CONFIDENCE.
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&& .MARINE...
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HIGH PRESSURE WILL CONTINUE TO SHIFT TO OUR NORTHEAST AND EAST THROUGH TONIGHT. THIS WILL PRODUCE A SOUTHEAST TO SOUTH FLOW AS A WARM FRONT LIFTS NORTH OF THE AREA BY LATE TONIGHT. WHILE THE FLOW IS MAINLY ON THE LIGHT SIDE, SOME NEARSHORE ENHANCEMENT COULD OCCUR DURING PEAK HEATING. WHILE THE MOISTURE IS FORECAST TO INCREASE WITH AN UPTICK IN THE SURFACE DEW POINTS, THE WATER IS ON THE WARM SIDE THEREFORE WE MAY NOT HAVE MUCH FOG DEVELOPMENT. OVERALL, THE CONDITIONS ARE ANTICIPATED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH TONIGHT. OUTLOOK... SUNDAY...SUB SCA. SUNDAY NIGHT AND MONDAY...SCA CONDITIONS POSSIBLE AS SEAS BUILD TO AROUND 5 FEET. SUB-SCA CONDITIONS EXPECTED AGAIN LATER MONDAY INTO TUESDAY. A COLD FRONT WILL APPROACH LATE TUESDAY EVENTUALLY CROSSING ON WEDNESDAY. SEAS WILL INCREASE BUT ARE EXPECTED TO REMAIN BELOW BELOW SCA.
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&& .RIP CURRENTS...
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TEMPERATURES WILL BE ABOVE NORMAL..AT TIMES MUCH ABOVE NORMAL.. THIS SUNDAY ONWARD THROUGH NEXT FRIDAY. THIS COMBINED WITH WATER TEMPERATURES GENERALLY IN THE 70S WILL MAKE IT FAVORABLE FOR BEACHGOERS TO SWIM. ALL GOOD! AS LONG AS THEY SWIM IN THE LIFEGUARDED AREAS. WHY? BECAUSE THERE IS ABOUT A 1 IN 18 MILLION CHANCE OF BECOMING A RIP CURRENT CASUALTY UNDER THE WATCHFUL EYES OF THE LIFE GUARDS....MUCH BETTER ODDS THAN IF YOU SWIM ON YOUR OWN WHERE RESCUE POTENTIAL IS NOT AS TIMELY. THIS SUMMER 4 HAVE DIED ALONG THE NJ SHORES DUE TO RIP CURRENTS AND WHAT WAS COMMON TO ALL...THEY SWAM WHERE LIFEGUARDS WERE NOT PRESENT...AND/OR AFTER THE HOURS THEY WERE ON DUTY. THE FAMILIES/FRIENDS WERE UNABLE TO RESCUE THE VICTIMS. MANY OF US DO NOT REALIZE HOW POWERFUL THE OCEAN IS...AND ITS NOT THE SAME SWIMMING IN THE POOL. THAT AND THE FACT THAT MANY OF US OVERESTIMATE WHAT WE CAN DO IN THE WATER/SWIMMING SKILL, CAN LEAVE A POTENTIAL VICTIM IN A LIFE THREATENING SITUATION. SWIM SAFE AND THE BEST WAY TO DO THAT IS SWIM IN THE PRESENCE OF LIFEGUARDS WHILE ENJOYING THIS FINE LABOR DAY WEEKEND WEATHER.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...MIKETTA NEAR TERM...GORSE SHORT TERM...GORSE LONG TERM...MIKETTA AVIATION...GORSE/MIKETTA MARINE...GORSE/MIKETTA RIP CURRENTS...DRAG

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