Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 110424 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1224 AM EDT FRI JUL 11 2014 .SYNOPSIS... A STATIONARY FRONTAL BOUNDARY WILL REMAIN OVER THE DELMARVA TONIGHT BEFORE SLOWLY PUSHING SOUTH OF THE AREA FRIDAY. HIGH PRESSURE BUILDS IN FROM THE NORTHEAST FRIDAY INTO SATURDAY. RETURN FLOW DEVELOPS LATE IN THE WEEKEND AND EARLY NEXT WEEK AS HIGH PRESSURE MOVES OFFSHORE AND AN STRONG UPPER LOW DIGS INTO THE UPPER MIDWEST. A COLD FRONT WILL APPROACH THE EASTERN SEABOARD TUESDAY BEFORE MOVING OFFSHORE BY WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE LAST OF THE HEAVY RAIN WAS WRINGING ITSELF OUT OVER THE WILMINGTON, DELAWARE AREA SHORTLY AFTER MIDNIGHT. THE PRECIPITATION IS EXPECTED TO DISSIPATE RAPIDLY DUE TO THE LOSS OF INSTABILITY AND AS THE MID LEVEL SHORT WAVE PASSES OFF THE COAST. THE REMAINDER OF THE FLASH FLOOD WATCH WAS ALLOWED TO EXPIRE AT MIDNIGHT. SCATTERED LIGHT RAIN SHOWERS REMAIN POSSIBLE IN OUR REGION DURING THE BALANCE OF THE NIGHT. THE WIND IS EXPECTED TO BE LIGHT AND IT WILL LIKELY FAVOR THE NORTH TO EAST QUADRANT. MINIMUM TEMPERATURES WILL BE MAINLY IN THE MIDDLE AND UPPER 60S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... THE PESKY FRONTAL BOUNDARY IS EXPECTED TO PUSH BACK OFFSHORE ON FRIDAY, AND STALL ACROSS THE OCEAN WATERS TO OUR EAST. PW VALUES CONTINUE TO LOWER THROUGH THE DAY, BUT THE MID-LEVEL THROUGH WILL BE MOVING OVERHEAD THROUGH THE DAY. THERE WILL REMAIN THE CHANCE FOR ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA, WITH THE BEST POTENTIAL ACROSS SOUTHERN NEW JERSEY AND SOUTHERN DELMARVA. HIGHS ON FRIDAY WILL DEPEND ON HOW MUCH SUNSHINE WE GET, WITH CLOUDY AREAS LIKELY BEING CLOSER TO THE COOLER MET GUIDANCE AND SUNNIER AREAS CLOSER TO THE WARMER MAV GUIDANCE. FOR NOW, WE TOOK A BLEND OF THE MAV/MET/MOS GUIDE FOR DAYTIME HIGHS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... SURFACE HIGH PRESSURE CENTERED JUST EAST OF NEW ENGLAND WILL PROVIDE NICE WEATHER THROUGH SATURDAY. FRIDAY NIGHT WILL FEATURE CLEAR SKIES AND COOL TEMPERATURES FOR THIS TIME OF YEAR, AND AN EASTERLY FLOW WILL KEEP HIGHS IN THE 80S ON SATURDAY. CONDITIONS WILL BEGIN TO DETERIORATE SOMEWHAT ON SUNDAY AS A FRONTAL BOUNDARY APPROACHES FROM THE WEST. CLOUDS WILL BE ON THE INCREASE AND SHOWERS AND THUNDERSTORM ACTIVITY WILL BECOME INCREASINGLY LIKELY FROM WEST TO EAST AS THE DAY WEARS ON. THESE CLOUDS SHOULD KEEP THE HIGH TEMPERATURES ON SUNDAY ONE OR TWO DEGREES COOLER THAN SATURDAY. AN ANOMALOUSLY STRONG NRN STREAM CLOSED LOW IS FORECAST TO DIVE SOUTHWARD FROM NEAR HUDSON BAY INTO THE UPPER MIDWEST EARLY NEXT WEEK, SETTING UP A RATHER UNUSUAL PATTERN FOR THIS TIME OF YEAR. THE MID-ATLANTIC REGION WILL BE SITUATED IN AN INCREASINGLY DIFFLUENT FLOW PATTERN ALOFT ON THE SOUTHEASTERN PERIPHERY OF THE AMPLIFYING UPPER TROUGH AND ON THE WESTERN PERIPHERY OF THE WESTERN ATLANTIC RIDGE. THE HEAT AND HUMIDITY WILL RETURN MONDAY AND TUESDAY DURING THIS TIME AS STRENGTHENING SOUTHWESTERLY FLOW AHEAD OF THE LOW BECOMES ESTABLISHED OVER THE EASTERN CONUS. MAX TEMPS IN THE LOWER 90S APPEAR LIKELY MONDAY AND TUESDAY. LEANED TOWARD THE SLOWER ECMWF SOLUTION REGARDING THE ARRIVAL OF THE FROPA ON TUESDAY. RAISED MAX TEMPS A FEW DEGREES FROM 12Z WPC GUIDANCE AS A SLOWER SOLUTION WOULD KEEP THE PRE-FRONTAL WARM AIR MASS THAT IS CHARACTERIZED BY 850 MB TEMPS NEAR 20C OVER THE AREA INTO TUESDAY. MAX TEMPS IN THE LOWER 90S OVER THE COASTAL MID-ATLANTIC REGION FOR ONE MORE DAY. MONDAY AND TUESDAY BOTH LOOK TO BE A RATHER STORMY PERIOD FOR THE AREA. THE FOCUS FOR CONVECTION APPEARS TO BE A PRE-FRONTAL/LEE TROUGH ON MONDAY AND THE MAIN COLD FRONT FOR TUESDAY. FAVORABLE DYNAMICS IN THE RIGHT ENTRANCE REGION OF AN UNSEASONABLY STRONG UPPER-LEVEL JET STREAK AND AHEAD OF THE APPROACHING LONG WAVE TROUGH ALSO LOOKS TO CONTRIBUTE TO SYNOPTIC LIFT OVER THE AREA ON TUESDAY. THERE ARE STILL PLENTY OF DETAILS THAT NEED TO BE WORKED OUT THIS FAR OUT, BUT THE POTENTIAL IS THERE FOR SEVERE THUNDERSTORM EVENTS BOTH DAYS. SPC HAS DEPICTED THE AREA IN A DAY 6 SLIGHT RISK FOR TUESDAY. COLD FROPA LIKELY TUESDAY NIGHT OR EARLY WEDNESDAY. MUCH COOLER AND DRIER CONDITIONS ARE FORECAST TO RETURN BEHIND THE COLD FRONT BY WEDNESDAY. THE 12Z ECMWF INDICATES H8 TEMPS DROPPING INTO THE SINGLE DIGITS BEHIND THE FRONT. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. PRECIPITATION IS MENTIONED IN THE TAFS FOR KPNE, KPHL AND KILG UNTIL 0600Z. OVERNIGHT, PRIMARILY VFR CONDITIONS WITH SOME MVFR VISIBILITY RESTRICTIONS AT SMALLER AIRPORTS AND TERMINALS. WINDS WILL BE LIGHT. AT THE COASTAL TERMINALS (KACY AND KMIV), WE WILL CONTINUE THE IFR CIG WITH SOME MVFR VSBY RESTRICTIONS. ON FRIDAY VFR CONDITIONS EXPECTED OR WILL BE REACHED (AT THE COASTAL TERMINALS) AT ALL AIRPORTS DURING THE MORNING. PCPN CHANCES OVERALL ARE LESS THAN TODAY AND NO MENTION WILL BE MADE. SOME CUMULUS CLOUDS SHOULD FORM, BUT NOT EXPECTING A VFR CIG. WINDS WILL BE LIGHT FROM THE EAST AND A BAY AND SEA BREEZE FRONT SHOULD FORM. NOT SURE IF A VERY SHARP DISCONTINUITY WILL FORM AS THE GENERAL WIND FIELD SHOULD BE FROM THE EAST. OUTLOOK... FRIDAY NIGHT THRU SATURDAY NIGHT...POTENTIAL FOR IFR CIGS WITH MARINE STRATUS TO IMPACT TERMINALS, PARTICULARLY ACY/MIV, FRIDAY AND SATURDAY NIGHTS WITH ONSHORE FLOW. OTHERWISE VFR EXPECTED WITH DRY CONDITIONS. SUNDAY AND MONDAY...CHANCE FOR SHRA/TSRA BOTH DAYS. BETTER CHANCE MAY BE MONDAY WITH A WELL-DEFINED SFC TROUGH DEVELOPING OVER THE EASTERN SEABOARD. LOCAL/BRIEF RESTRICTIONS POSSIBLE. TUESDAY...BETTER CHANCE FOR SHRA/TSRA TUESDAY AS A COLD FRONT APPROACHES. && .MARINE... SUB-ADVISORY CONDITIONS ARE EXPECTED THROUGH TONIGHT AND FRIDAY WITH A FRONTAL BOUNDARY DRAPED ACROSS THE WATERS. THERE REMAINS A CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH FRIDAY; EXPECT HIGHER WINDS AND WAVES NEAR THUNDERSTORMS. OUTLOOK... FRIDAY NIGHT THROUGH AND SATURDAY NIGHT...HIPRES BUILDS IN FROM THE NORTHEAST STATES TO START THE WEEKEND. ONSHORE FLOW WILL BE LIGHT. SUNDAY THROUGH TUESDAY...WINDS VEER, BECOMING SOUTHWESTERLY ON SUNDAY. SOUTHWEST WINDS STRENGTHEN MONDAY BUT SHOULD REMAIN BELOW SCA LEVELS. GUSTY SOUTHERLY WINDS AHEAD OF A COLD FRONT ON TUESDAY. MARGINAL SCA POSSIBLE. CHANCE FOR SHRA/TSRA LATE SUNDAY. BETTER CHANCE ON MONDAY AND TUESDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLEIN NEAR TERM...IOVINO SHORT TERM...ROBERTSON LONG TERM...KLEIN/MIKETTA AVIATION...GIGI/KLEIN MARINE...KLEIN/ROBERTSON

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