Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 300406 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1206 AM EDT SAT AUG 30 2014 .SYNOPSIS...
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HIGH PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF OUR AREA OVERNIGHT. A WARM FRONT WILL LIFT NORTH OF OUR REGION LATE SATURDAY, THEN THIS FRONT WILL BECOME NEARLY STATIONARY NEAR THE CANADIAN BORDER DURING SUNDAY THROUGH TUESDAY. A WEAK COLD FRONT IS THEN PROJECTED TO MOVE THROUGH OUR REGION LATE TUESDAY INTO EARLY WEDNESDAY, FOLLOWED BY HIGH PRESSURE RETURNING LATER IN THE WEEK.
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&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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HIGH PRESSURE AT THE SURFACE WILL CONTINUE TO SHIFT TO OUR NORTHEAST OVERNIGHT, ALLOWING FOR A WEAK RETURN FLOW TO OCCUR. MEANWHILE, AN UPPER-LEVEL RIDGE WILL CREST OVER THE REGION OVERNIGHT. THERE WILL BE SOME HIGH LEVEL CLOUDS AT TIMES CRESTING THIS RIDGE, WHILE SOME DEEPER MOISTURE IS LOCATED TO OUR SOUTHWEST. THE LIGHT WINDS AND LITTLE IN THE WAY OF CLOUDS SO FAR HAS RESULTED IN DECENT RADIATIONAL COOLING, ESPECIALLY AREAS WHERE THE DEW POINTS ARE LOWER SO FAR. THE COOLING OF THE BOUNDARY LAYER COMBINED WITH LIGHT WINDS MAY RESULT IN PATCHY GROUND FOG. THE HOURLY TEMPERATURES WERE ADJUSTED BASED ON THE LATEST OBSERVATIONS, THEN THE LAMP/LAV GUIDANCE WAS BLENDED IN TO HELP ASSIST WITH TRENDS.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... WINDS WILL SHIFT TO SOUTHERLY AND INCREASE BY AT LEAST MID MORNING. THIS WARM AIR ADVECTION WILL RESULT IN MAX TEMPS A FEW DEGREES HIGHER THAN TODAY, EVEN IN SPITE OF ANY PATCHY FOG THAT MAY LINGER INTO THE MID MORNING HOURS. SOUTHERLY GUSTS 15 MPH DURING THE AFTERNOON. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
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HEMISPHERIC MODEL ANALYSIS SHOWS SOUTHEAST U.S. RIDGING WITH WEAK TROUGHING NORTH OF THE GREAT LAKES AND MID-WEST AT THE START OF THE LONG TERM. BETTER TROUGHING ACROSS THE WESTERN U.S. MOVES EASTWARD EVENTUALLY CARVING INTO THE TOP OF THE SOUTHEAST RIDGE BY EARLY NEXT WEEK. THE PREVAILING SOUTHWEST FLOW ALOFT DECREASES, ULTIMATELY BECOMING MORE ZONAL, AS THE NORTHERN STREAM OF THE JET MOVES TO THE NORTH OF OUR REGION LATE IN THE PERIOD. SUNDAY - TUESDAY...SLOW SAGGING BOUNDARY TO THE NORTHWEST OF THE REGION SLOWS EVEN FURTHER AND MORE THAN LIKELY BECOMES PSEUDO-STATIONARY WITH STRONG RIDGING TO OUR SOUTHEAST. MID AND UPPER LEVEL FLOW, BEING SOUTHWESTERLY, KEEP THIS BOUNDARY DRAPED JUST TO OUR NORTHWEST AS WARM AND MOIST GOMEX AIR IS PUMPED INTO THE REGION. MULTIPLE MID-LEVELS WAVES, WITH WEAK SURFACE TROUGHS, TRAVERSE THE REGION EACH DAY PROVIDING CHANCES OF SHOWERS AND THUNDERSTORMS. THE BEST CHANCES FOR CONVECTION CONTINUES TO HONE IN ON THE SUNDAY NIGHT INTO MONDAY TIMEFRAME AS THE STRONGEST OF THE MID-LEVEL WAVES MOVES THROUGH. AFTERWARDS, HIGHER THAN NORMAL PWAT AIRMASS, POSSIBLY EXCEEDING 2 INCHES, AND AMPLE INSTABILITY EACH AFTERNOON SHOULD ALLOW FOR DIURNALLY DRIVEN CONVECTION. TEMPERATURES AND UNFORTUNATELY THE DEWPOINTS WILL BE ON THE INCREASE THIS TIMEFRAME MAKING CONDITIONS FEEL TRULY LIKE AN EARLY AUGUST DAY, IN EARLY SEPTEMBER. WEDNESDAY...LOW PRESSURE SYSTEM WELL TO THE NORTH OF THE REGION SENDS A SOMEWHAT STRONGER COLD FRONT TOWARDS OUR AREA. RIDGING TO OUR SOUTH SHOULD PREVENT A QUICK PASSAGE, BUT NONE-THE-LESS WE CURRENTLY EXPECT THE FRONT TO CLEAR OR BECOME WASHED OUT LATER IN THE DAY. STILL HAVE SOME LOW-END CHANCES, MOSTLY NORTH, WITH THIS FRONT THOUGH IT CONTINUES TO LOSE STEAM RUNNING INTO THE BUILDING RIDGE TO OUR SOUTH. WE SHOULD BE DRYING OUT NORTH TO SOUTH BY THE AFTERNOON HOURS WITH LOWERING OF THE DEWPOINTS...TEMPERATURES SHOULD STILL BE IN THE UPPER-80S. THURSDAY - FRIDAY...HIGH PRESSURE CONTINUES TO BUILD BACK INTO OUR REGION WITH ZONAL FLOW ALOFT. THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF MID-LEVEL FORCING FROM ANY OF THE PASSING SHORTWAVES, MOST OF THE ENERGY STAYS WELL TO OUR NORTH...WE SHOULD BE DRY BOTH DAYS. TEMPERATURES WILL VENTURE BACK DOWN INTO THE NORMAL RANGE WITH CONTINUED DEWPOINT LOWERING.
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&& .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. OVERNIGHT...VFR OVERALL. LOCALIZED GROUND FOG MAY DEVELOP TOWARD DAYBREAK, HOWEVER CONFIDENCE IS ON THE LOW SIDE. LIGHT MAINLY SOUTHEAST WINDS. SATURDAY...LOCALIZED EARLY MORNING FOG POSSIBLE, OTHERWISE VFR WITH SCATTERED TO BROKEN BASES DEVELOPING AROUND 5000 FEET. SOUTHERLY WINDS INCREASING TO AROUND 10 KNOTS. SATURDAY NIGHT...GENERALLY VFR. HOWEVER, AN INCREASE IN MOISTURE MAY RESULT IN PATCHY STRATUS AND/OR FOG LATE. SOUTH-SOUTHWEST WINDS 5 KNOTS OR LESS. OUTLOOK... SUNDAY...VFR. SCATTERED SHOWERS AND THUNDERSTORMS NORTH AND WEST OF PHL. MDT CONFIDENCE. MONDAY - WEDNESDAY...VFR. SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE EVERYWHERE. LOW TO MDT CONFIDENCE ON PRECIP COVERAGE.
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&& .MARINE... WAVE HEIGHTS SHOULD REMAIN 2 TO 4 FEET, AND WINDS LESS THAN 20KT, THUS CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. PATCHY FOG MAY DEVELOP SATURDAY MORNING ON THE DELAWARE BAY, ESPECIALLY THE UPPER BAY, BUT SHOULD DISSIPATE BY LATE MORNING AS WINDS INCREASE. OUTLOOK... SUNDAY - WEDNESDAY...SUB-SCA CONDITIONS EXPECTED ACROSS OUR WATERS WITH HIGH PRESSURE OFFSHORE. COLD FRONT WILL APPROACH MONDAY AND TUESDAY EVENTUALLY CROSSING ON WEDNESDAY. WINDS WILL BACK TOWARDS THE SOUTHWEST ON SUNDAY AND REMAIN THAT WAY THROUGH TUESDAY. SEAS WILL INCREASE BUT REMAIN BELOW SCA AT THIS TIME. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANCK/GORSE NEAR TERM...GORSE SHORT TERM...DRAG/JOHNSON LONG TERM...HEAVENER AVIATION...GORSE/HEAVENER MARINE...DRAG/HEAVENER/JOHNSON

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