Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 280455 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1255 AM EDT MON JUL 28 2014 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF PENNSYLVANIA TONIGHT AND LIFT INTO NEW ENGLAND MONDAY, PULLING A COLD FRONT ACROSS THE AREA. HIGH PRESSURE WILL BEGIN MOVING INTO THE AREA LATER TUESDAY, AND REMAIN IN CONTROL OF THE WEATHER FOR THROUGH THE END OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WE HAVE CANCELLED THE SEVERE THUNDERSTORM WATCH AT THIS TIME WITH A MAJORITY OF THE CONVECTION NOW HEADING INTO SOUTH AND CENTRAL NEW JERSEY. VERY HEAVY RAINFALL AND FREQUENT LIGHTNING IS STILL OCCURRING WITH THESE STORMS, SO THEY ARE NOTHING TO SNEEZE AT. THEY WILL CONTINUE TO PUSH TOWARDS THE EAST-NORTHEAST DURING THE COURSE OF THE EARLY MORNING HOURS. THERE STILL REMAINS AMPLE BOUNDARY LAYER CAPE WITH NEGATIVE LIS AND SHOWALTER INDEXES, SO MORE ISOLATED TO SCATTERED CONVECTION IS LIKELY TO OCCUR THROUGH THE EARLY MORNING HOURS FROM WEST TO EAST...WELL AHEAD OF THE APPROACHING COLD FRONT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... SHORT WAVES ROTATING AROUND THE ANOMALOUS STRONG 500MB TROF WILL PASS ACROSS OUR CWA ON MONDAY. CONVECTIVE TEMPS (SELF DESTRUCT SUNSHINE) WILL BE REACHED EASY AND EARLY. THE OVERALL FCST CAPE AND INSTAB ALOFT ON THE BIG THREE MODELS ARE NOT UNSTABLE ENOUGH FOR THUNDER. OTHER THAN SOME EARLY THUNDER NORTHEAST CWA, WE KEPT IT AS SHOWERS WITH HIGHEST POPS NORTHWEST THE REST OF THE DAY. STAT GUIDANCE FOR MAX TEMPS APPEARS TOO HIGH IN THE SERN CWA UNLESS THE COLD FRONT IS 2-4HRS SLOWER THAN PROGGED. WE WERE LOWER THAN GFS MOS THERE AND CLOSE TO A STAT GUIDANCE BLEND ELSEWHERE. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A MOSTLY DRY START TO THE LONG TERM FORECAST, WITH PRECIPITATION CHANCES INCREASING LATER IN THE WEEK INTO THE WEEKEND. THERE MAY BE SOME LINGERING SHOWERS MONDAY EVENING AS THE FRONT CONTINUES TO PUSH OFFSHORE AND THE MID-LEVEL TROUGH LIFTS OUT, BUT ANY PRECIPITATION IS EXPECTED TO END BY MIDNIGHT. MUCH OF THE UPCOMING WEEK IS EXPECTED TO REMAIN MOSTLY DRY AS PW VALUES DROP TO AN INCH OR LOWER FOR TUESDAY AND WEDNESDAY, BUT MAY RETURN TO 1-1.25 INCHES FOR THURSDAY AND NEAR 1.5 INCHES FOR FRIDAY. HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS THE REGION, WHILE THE BROAD MID/UPPER TROUGH REMAINS IN PLACE ACROSS MUCH OF THE EASTERN HALF OF THE COUNTRY. THERE AREA NO SIGNIFICANT SHORT WAVE/VORTICITY IMPULSES THAT ARE FORECAST TO MOVE THROUGH FOR MUCH OF THE WEEK, BUT WITH THE TROUGH IN PLACE AND DAYTIME HEATING, THERE COULD BE ENOUGH DAYTIME INSTABILITY TO CREATE ISOLATED SHOWERS OR THUNDERSHOWERS FOR THE LATTER HALF OF THE WEEK. EACH DAY THE CHANCES INCREASE SLIGHTLY AND EXPAND IN COVERAGE. HOWEVER, WE DO NOT HAVE MORE THAN A SLIGHT CHANCE PROBABILITY THROUGH FRIDAY AT THIS TIME. AS WE MOVE INTO NEXT WEEKEND, WE GET A MORE SOLID RETURN OF MOISTURE ACROSS THE AREA AS PW VALUES REBOUND O 1.25-1.5 INCHES. WE ALSO HAVE A BETTER CHANCE OF VORTICITY IMPULSES AFFECTING OUR AREA WITHIN THE SOUTHWEST FLOW ALOFT, AND WITH THE COASTAL FRONT TRYING TO PUSH BACK CLOSER TO SHOWER, WE MAY HAVE A FOCUS FOR PRECIPITATION TO FORM. THEREFORE THE PRECIPITATION CHANCES INCREASE INTO NEXT WEEKEND. TEMPERATURES THROUGH THE EXTENDED ARE FORECAST TO BE CLOSE TO OR SLIGHTLY BELOW NORMAL. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. LINE OF STRONG THUNDERSTORMS HAS PASSED THROUGH MOST OF OUR I-95 CORRIDOR TERMINALS AND WILL CONTINUE TO PUSH TOWARDS THE EAST EARLY THIS MORNING. OVERNIGHT PREVAILING MVFR CONDITIONS EXPECTED TO CONTINUE DURING SHOWERS. ISOLATED THUNDER POSSIBLE, BUT CONFIDENCE TOO LOW AS TO WHERE OR WHEN TO INCLUDE. WINDS WILL BE LIGHTER, GENERALLY FROM THE SOUTH. IMPROVEMENT TOWARD MORNING AS PCPN ENDS. THINKING TOO MUCH WIND FOR SGFCNT FOG TO FORM. MONDAY MORNING, VFR CONDITIONS WITH A CUMULUS BASED CIG OCCURRING. GUSTY WEST WINDS, ESPECIALLY FOR JULY, WITH SUSTAINED SPEEDS AROUND 15 KTS AND GUSTS TO AROUND 25 KTS. SOME WIDELY SCATTERED SHOWERS SHOULD START DEVELOPING TOWARD THE END OF THE CURRENT TAF FCST PERIOD. GREATEST CONFIDENCE NORTH, REASON FOR NOW LEFT OUT OF KPHL TAF. OUTLOOK... MONDAY NIGHT-WEDNESDAY NIGHT...MAINLY VFR THURSDAY-FRIDAY...MAINLY VFR. ISOLATED SHOWERS/THUNDERSTORMS POSSIBLE BOTH AFTERNOONS, ESPECIALLY FRIDAY. && .MARINE... A SMALL CRAFT ADVISORY WILL BE ISSUED FOR TONIGHT AND MONDAY FOR THE OCEAN WATERS. ONE WILL BE ISSUED FOR DELAWARE BAY FOR MONDAY. FIRST FOR THE LIKELIHOOD THAT SEAS REACH 5 FEET THIS EVENING AND THEN THE LIKELIHOOD OF NON CONVECTIVE WEST WIND GUSTS REACHING THE CRITERIA ON DELAWARE BAY AS WELL AS THE OCEAN WATERS DURING THE DAY ON MONDAY. WAVE WATCH GUIDANCE BRINGS SIX FOOT SEAS AS IS INTO OUR COASTAL WATERS, SHAVING A FOOT OR SO OFF WOULD STILL GET US THERE TONIGHT. TOUGH NIGHT AS IT IS WITH THUNDERSTORMS EXPECTED. ON MONDAY MORE OF THE GUSTINESS MAY BE CONCENTRATED AROUND THE INLETS AND IN DELAWARE BAY WITH POSSIBLY LESS GUSTINESS FARTHER OFFSHORE. THE GRADIENT AND WINDS SHOULD START RELAXING LATER IN THE DAY ON MONDAY. OUTLOOK... MONDAY NIGHT-FRIDAY...SMALL CRAFT ADVISORY CONDITIONS POSSIBLE EARLY MONDAY NIGHT, SUBSIDING AND REMAINING BELOW ADVISORY LEVELS THROUGH THE PERIOD. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450>455. SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ430-431. && $$ SYNOPSIS...ROBERTSON NEAR TERM...HEAVENER SHORT TERM...GIGI LONG TERM...ROBERTSON AVIATION...GIGI/ROBERTSON MARINE...GIGI/ROBERTSON

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