Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 230118 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 918 PM EDT FRI MAY 22 2015 .SYNOPSIS... HIGH PRESSURE ACROSS THE GREAT LAKES WILL BUILD EASTWARD TONIGHT REACHING OUR REGION TOMORROW. THIS AREA OF HIGH PRESSURE WILL SLIDE OFF THE COAST SUNDAY. A WARM FRONTAL BOUNDARY WILL THEN PASS NORTHWARD THROUGH OUR REGION ON MONDAY. A TROUGH OF LOW PRESSURE WILL MOVE IN BEHIND THE WARM FRONTAL PASSAGE FOR THE MIDDLE AND LATER HALF OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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MOSTLY CLR SKIES OVERNIGHT. TEMPERATURES WILL DROP OFF OVERNIGHT BEHIND A WEAK COLD FRONT, WITH EVERYONE DROPPING CLOSE TO 10 DEGREES BELOW NORMAL. THERE COULD EVEN BE SOME PATCHY FROST ACROSS THE NORTHERN AREAS. PORTIONS OF THE POCONOS HAVE THE BEST CHANCE OF BEING THE COLDEST WITH MORE WIDESPREAD FROST, SO AN ADVISORY HAS BEEN ISSUED FOR CARBON/MONROE, PENNSYLVANIA. WE DID INCLUDE PATCHY FROST FOR SUSSEX COUNTY, NEW JERSEY, BUT ARE NOT SURE IT WILL BE AS WIDESPREAD AS THE POCONOS, SO WE DID NOT ISSUE AN ADVISORY THERE.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... OTHER THAN THE PATCHY MORNING FROST UP NORTH,SATURDAY WILL BE A BEAUTIFUL DAY AS HIGH PRESSURE CRESTS OVER THE AREA AND TEMPERATURES WILL REMAIN AROUND CLOSE TO 10 DEGREES BELOW NORMAL. PW VALUES WILL DROP BELOW 1/4 OF AN INCH, AND ONLY CIRRUS CLOUDS ARE EXPECTED THROUGH THE DAY. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... THIS FORECAST IS WEIGHED MORE ON THE ECMWF OPERATIONAL RUNS TODAY AND IT`S RESPECTIVE ENSEMBLE MEAN. THIS RESULTS IN A DRIER AND HOT PERIOD FOR MOST OF NEXT WEEK. THE GFS LOOKS TO HAVE TO MUCH CONVECTION. THE MAIN REASON FOR THIS CONCLUSION IS THE LACK OF A FOCUSED TRIGGERING MECHANISM PRESENT. THE FIRST HEAT WAVE OF THE SEASON POSSIBLE TUE-THU NEXT WEEK, MAYBE PAST THU?, PARTICULARLY PHL METRO AREA AND SW. SATURDAY NIGHT THROUGH SUNDAY NIGHT: HIGH PRESSURE WILL MOVE OFF THE CAROLINA COASTLINE. THIS WILL LEAD TO A MORE DOMINANT SOUTH TO SOUTHWEST WIND AND A WARM FRONTAL BOUNDARY MOVING NORTH INTO THE REGION SUNDAY NIGHT. MOISTURE WILL BE ON THE INCREASE WITH THE TEMPERATURE TRENDS ON BOTH HIGHS AND LOWS INCREASING. STILL PLEASANT OVERALL WITH PLENTY OF SUNSHINE! MONDAY: A WARM FRONTAL BOUNDARY WILL MOVE THROUGH EARLY IN THE DAY. SOME CONVECTION MAY ATTEMPT TO FIRE UP OR MOVE ALONG THE BOUNDARY WITH THE HIGHEST CHANCES ACROSS NORTHERN PARTS OF THE CWA. HOWEVER, THE TREND OVER THE PAST FEW MODEL CYCLES IS FOR DECREASED CHANCES OF SHOWER OR THUNDERSTORM ACTIVITY. ONLY WENT WITH SLIGHT CHANCE FOR THE LEHIGH VALLEY AND POCONOS IN THIS PERIOD. SHEAR IS GOING TO BE VERY WEAK THROUGH ALL PERIODS, SO THE MAIN THREATS FROM ANY THUNDERSTORMS WILL BE FROM LOCALLY HEAVY DOWNPOURS AND FREQUENT LIGHTNING, HIGH PW VALUES. CONTINUED WARMING TREND AND SOUTHERLY FLOW AFTER THE WARM FRONTAL PASSAGE AS WELL. SOME WIND GUSTS FROM 15- 20 MPH POSSIBLE AS WELL BASED ON GFS SOUNDING ANALYSIS MONDAY AFTERNOON. MONDAY NIGHT THROUGH TUESDAY NIGHT: REGION FIRMLY IN WARM SECTOR. WITH CONTINUED SOUTHERLY-SOUTHWESTERLY WINDS AND WAA. SOME GUSTS CLOSE TO 20 MPH ARE ONCE AGAIN POSSIBLE TUESDAY AFTERNOON. SURGING 925 MB TEMPS FROM 20-25C MAY CONTRIBUTE TO THE FIRST WIDESPREAD 90 DEGREE DAY OF THE YEAR BY TUESDAY. A BROAD TROUGH TO OUR NORTHWEST MAY BE ENOUGH OF A TRIGGER FOR A THUNDERSTORM OR TWO ACROSS THE LEHIGH VALLEY NORTH AND WEST. OVERALL, TREND IN THE NEXT FEW PERIODS, LIKE WITH MANY WEATHER SYSTEMS IN RECENT WEEKS IS TO LOWER POPS AS WE GET CLOSER TO AN EVENT. HIGHEST CHANCES FOCUSED NW OF PHL. WEDNESDAY THROUGH FRIDAY: WELL WE CONTINUE TO BE ON THE BACKSIDE OF THE RIDGE WITH THE A SIMILAR PATTERN TO MON-TUE. AS STATED EARLIER, THIS FORECAST LEANS IN THE DIRECTION OF THE ECMWF AND IT`S ENSEMBLE MEAN. THAT LIMITS THE INFLUENCE OF THE INCOMING TROUGH ALLOWING FOR A HOTTER PERIOD WITH LOWER RAIN CHANCES. 925 MB TEMPERATURES SUGGEST THE HOTTEST DAY TO BE WEDNESDAY, IN THE LOW 90`S WITH HIGHS AROUND 90 FOR THURSDAY AND FRIDAY. MUGGY NIGHTS ARE LIKELY AS WELL WITH LOWS IN THE UPPER 60`S TO 70 ON AVERAGE. BY WEEKS END, THE INFLUENCE OF ANY TROUGH MAY INCREASE. THIS WOULD LEAD TO MORE IN THE WAY OF SCATTERED CLOUDS AND POPCORN THUNDERSTORM CHANCES. TEMPERATURE FORECASTS ARE WARMER THAN THE ENSEMBLE GUIDANCE OUTPUT AT THIS TIME FOR HIGHS, PARTICULARLY THE GFS WHICH LOOKS TO MUCH DRIVEN BY QUESTIONABLE CONVECTION. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. WIND GUSTS SHOULD SLOWLY DIMINISH AROUND AN AFTER SUNSET. A COLD FRONT WILL MOVE THROUGH THE AREA AROUND/AFTER SUNSET WHICH MAY HAVE A FEW GUSTS RIGHT BEHIND IT, BUT WINDS WILL DROP OFF OVERNIGHT BEHIND THE FRONT AS HIGH PRESSURE BEGINS TO MOVE INTO THE AREA. VFR CONDITIONS AND LIGHTER WINDS WILL PERSIST FOR SATURDAY. THE NORTHWEST WINDS SHOULD BECOME MORE WEST AND SOUTHWEST THROUGH THE DAY. OUTLOOK... SATURDAY THROUGH SUNDAY NIGHT: VFR, SOUTHWEST WINDS AROUND 10 KNOTS. MONDAY THROUGH WEDNESDAY: VFR, WITH SOME LOWER RESTRICTIONS POSSIBLE IN ANY ISOLATED TO SCATTERED STORMS. BEST CHANCE FOR STORMS ABE AND RDG TUESDAY AND WEDNESDAY IN THE LATE AFTERNOON HOURS. SOUTH TO SOUTHWEST WINDS WITH SOME GUSTS FROM 15-20 KNOTS POSSIBLE EACH AFTERNOON. && .MARINE...
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WINDS ACROSS DEL BAY AND THE SRN WATERS HAVE DECREASED QUITE A BIT OVER THE PAST HOUR. I HAVE DECIDED TO DROP THE SC FLAG FOR THOSE AREAS. THE SCA FOR THE NRN WATERS WILL CONTINUE OVERNIGHT.FAIR WEATHER OVERNIGHT AND SAT. NW WINDS BECOMING W LATE...SPEEDS MOSTLY 10 TO 15 KNOTS...FEW GUSTS TO 20 KTS POSSIBLE EARLY. OUTLOOK... SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGHOUT THE ENTIRE OUTLOOK PERIOD. HOWEVER, ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE MONDAY THROUGH WEDNESDAY FOCUSED IN THE AFTERNOON AND EVENING. WINDS WILL BE OUT OF THE SOUTH TO SOUTHWEST WITH SOME WIND GUSTS AROUND 20 KNOTS. HIGHEST SEAS AROUND FOUR FEET ACROSS THE NORTHERN WATERS ON TUESDAY.
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&& .RIP CURRENTS... POTENTIAL HEAT WAVE NEXT WEEK. THIS PLUS WATER TEMPS CONTINUING ABOVE NORMAL IS NOT GOOD FOR SAFETY. ONCE IT TURNS HOT AND BEACHES ARE UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE SMART ABOUT ANY SWIMMING EARLY THIS SEASON. RIP CURRENT AWARENESS WEEK FOR MT HOLLY IS JUNE 7-13 WITH PSAS VIA PUBLIC INFORMATION STATEMENTS, SOCIAL MEDIA, NOAA WEATHER RADIO AND ANY MEDIA INTERVIEWS DESIRED (CONTACT OFFICE). FOR RIP CURRENTS: DESPITE ANTICIPATED PROJECTIONS OF LOW OR MODERATE RISK THROUGH THE MEMORIAL DAY WEEKEND, EARLY SEASON FATALITIES OCCUR WHEN SWIMMING AT UNGUARDED TIMES/LOCATIONS. WEAKER SWIMMERS OR SWIMMING IN AREAS WHERE RIP CURRENTS ARE STRONGER (JETTIES) CAN QUICKLY BECOME LIFE THREATENING. WHEN TRAINED LIFEGUARDS ARE NOT NEARBY, TIMELY RESCUE IS MUCH LESS LIKELY. LETS GET THROUGH THE MONTH OF MAY WITH ALL SWIMMERS SAFE! PLEASE BROADCAST THIS MESSAGE: FOR ULTIMATE SAFETY, ALWAYS SWIM IN THE PRESENCE OF LIFE GUARDS! THANK YOU! && .CLIMATE... **LITTLE DOUBT THAT A TOP 10 WARMEST MAY WILL OCCUR IN LARGE PORTIONS OF OUR FORECAST AREA** THE FIRST 21 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING ABOUT 6 DEGREES ABOVE NORMAL. RUNNING THE NUMBERS FROM THIS MORNINGS 330AM FCST THROUGH THE 28TH AND THE 00Z/22 FTPRHA (GFS MOS) FOR THE LAST 3 DAYS BEYOND OUR WFO RESPONSIBILITY (29-31) WE FIND THE FOLLOWING. FOR PHILADELPHIA...PERIOD OF RECORD (POR) BACK TO 1874. PROJECTING A MONTHLY AVERAGE TEMPERATURE OF 69 TO 70, AT LEAST 5 TO 6 DEGREES ABOVE NORMAL. HEADING FOR SECOND OR THIRD WARMEST ON RECORD. WARMEST WAS 70.8 IN 1991. THEN 69.2 2004. FOR ALLENTOWN...PERIOD OF RECORD (POR) BACK TO 1922. PROJECTING 65.9 OR ABOUT 6 DEGREES ABOVE NORMAL WHICH WOULD BE 4TH-5TH WARMEST ON RECORD. 1991 WAS THE WARMEST WITH 67.2, FOLLOWED BY 2012 66.1, THEN 1944 WHEN MAY AVERAGED 66.0 AND FINALLY THE 2004 65.9 DEGREE AVG. THE NEXT WARMEST WAS 65.3 IN 1939. THE FOLLOWING WAS POSTED BECAUSE ITS LIKELY THAT WE WILL EXPERIENCE OUR FIRST 90 IN PHILADELPHIA BY THE MIDDLE OF NEXT WEEK, AND POSSIBLY A HEAT WAVE. NORMAL FIRST DATE OF 90 OR HIGHER. PHILADELPHIA MAY 29 ALLENTOWN MAY 30 WILMINGTON JUNE 4 ATLANTIC CITY JUNE 11. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ054-055. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ450>453.
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&& $$ SYNOPSIS...GAINES NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...GAINES AVIATION...GAINES/ROBERTSON MARINE...GAINES/ROBERTSON FIRE WEATHER... RIP CURRENTS... CLIMATE...

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