Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 191422 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 922 AM EST WED NOV 19 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN TO THE REGION TODAY...FOLLOWED BY A COLD FRONTAL PASSAGE ON THURSDAY. BEHIND THIS FRONT, A MUCH STRONGER HIGH PRESSURE SYSTEM WILL MOVE IN FROM THE WEST ON FRIDAY, THEN REMAIN OVER THE AREA ON SATURDAY BEFORE MOVING OFFSHORE ON SUNDAY. MEANWHILE, LOW PRESSURE WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND MOVE TO NEAR THE GREAT LAKES. THE LOW WILL INTENSIFY AS IT MOVES EASTWARD EARLY NEXT WEEK, BRINGING A COLD FRONT THROUGH THE REGION MONDAY NIGHT OR TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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9:30 AM UPDATE: FORECAST ON TRACK. MINOR ADJUSTMENTS MADE TO TEMPERATURES BASED ON 14Z METAR OBS. THINK WE CAN ADD ABOUT TEN DEGREES TO CURRENT TEMPERATURES TODAY WHICH WOULD PLACE US IN THE MID PERHAPS UPPER 30`S SOUTH. A COLD DAY FOR NOVEMBER BUT SUNNY AS HIGH PRESSURE MOVES INTO THE REGION. THE UPPER TROUGH THAT HAS LEFT A LARGE PART OF THE UNITED STATES IN AN DEEP FREEZE WILL REMAIN OVERHEAD TODAY, ALTHOUGH IT DOES FLATTEN OUT OVER THE EAST AS SHORTWAVE ENERGY MOVES OFF THE NEW ENGLAND COAST AHEAD OF THE LARGE SCALE TROUGH. SOUTHWEST FLOW DEVELOPING THIS AFTERNOON WILL ADVECT WARMER AIR ALOFT INTO THE REGION. THE WAA IS FORECAST TO BE MOST NOTABLE IN THE 4-8 KFT LAYER ABOVE THE SURFACE, WHICH WOULD BE ABOVE THE MIXED LAYER AND THUS NOT HELP MUCH TO MODERATE SURFACE TEMPS. MAX TEMPS TODAY ARE GENERALLY IN THE LOW TO MID 30S AND ARE SIMILAR TO YESTERDAY AFTERNOON. THE PRESSURE GRADIENT WILL WEAKEN OVER THE MID-ATLANTIC REGION TODAY AS THE 1033 MB SURFACE HIGH THAT IS CURRENTLY OVER THE NORTHERN GULF COAST STATES RIDGES DOWNSTREAM TOWARD OUR AREA WHILE LOW PRESSURE OVER NORTHEASTERN CANADA LIFTS FARTHER AWAY FROM OUR AREA. THE WINDS WILL BE LIGHTER TODAY COMPARED TO YESTERDAY. NONETHELESS, A 10-15 MPH WIND IN THIS ARCTIC AIRMASS WILL RESULT IN WIND CHILLS THAT ARE ABOUT 10 DEGREES LOWER THAN THE AMBIENT TEMPERATURE. TODAY WILL START OFF SUNNY BEFORE MID AND HI CLOUDS STREAM IN FROM THE WEST DURING THE MID TO LATE AFTERNOON.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... A NORTHERN STREAM SHORTWAVE TROUGH DIVING SOUTHEASTWARD FROM MANITOBA WILL LEAD TO THE DEVELOPMENT OF A GREAT LAKES LOW TONIGHT. THE FLOW DOWNSTREAM OF THIS SYSTEM WILL BACK FURTHER OUT OF THE SOUTHWEST ALOFT AND THE SOUTH AT THE SURFACE. 00Z NAM/GFS FORECAST SOUNDINGS BOTH INDICATE A 50 KT SOUTHWESTERLY LOW-LEVEL JET DEVELOPING OVERHEAD TOWARD MIDNIGHT. AFTER THE AIRMASS INITIALLY COOLS TOWARD SUNSET, TEMPS ARE FORECAST TO REMAIN STEADY OR EVEN WARM LATER IN THE EVENING AND OVERNIGHT IN RESPONSE TO WAA OCCURRING WITHIN THE BOUNDARY LAYER AND INCREASING MID CLOUDS. LOWS RANGING FROM AROUND 20F IN THE POCONOS TO AROUND 30F ALONG THE COAST ARE FORECAST TO OCCUR IN THE EVENING FOR MOST LOCATIONS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... ON THU, LOW PRES WILL BE LOCATED OVER ERN CAN HE LOW WILL MOVE EWD, BRINGING A CDFNT THU THE REGION. THE FRONT IS WEAK AND HAS LITTLE MOISTURE TO WORK WITH, SO WE ARE KEEPING THINGS DRY. BEHIND THE FRONT, A LARGE AREA OF HIGH PRES OVER THE MIDSECTION OF THE COUNTRY WILL WORK ITS WAY EWD. THIS WILL ALSO BRING A PATN CHANGE TO THE AREA, AS THE TROF THAT BROUGHT THE UNSEASONABLY COLD WX TO THE AREA MOVES OFFSHORE AND HGTS RISE AND THE TROF IS REPLACED BY A RIDGE BY THE WEEKEND. THE HIGH WILL BE OVERHEAD ON SAT AND MOVE OFFSHORE ON MON. EXPECT SEVERAL WARM DAYS WITH WARMING TEMPS. AS THE SWLY FLOW INCREASES WITH THE HIGH MOVG OFFSHORE, THERE WILL BE A MARKED RISE IN TEMPS FROM SAT TO SUN AND FURTHERMORE INTO MON. AS THE HIGH MOVES OVER THE ERN CONUS, AN AREA OF LOW PRES WILL TAKE SHAPE OVER THE SRN PLAINS ON SAT. THIS LOW WILL MOVE NNEWD TO NR ST. LOUIS BY 23/18Z AND NR THE GRTLKS BY 24/00Z. THE POSN OF THE LOW IN THE GFS AND ECMWF ARE SIMILAR BY 24/00Z THOUGH THE ECMWF IS ABOUT 8 MB STRONGER. BY SUN MRNG, THE GFS AND CMC HAVE A WMFNT TO THE N OF THE PA/NY BRDR AND KEEP PRECIP N OF THE REGION, WHILE THE ECMWF IS A BIT FURTHER S, WITH SOME PRECIP OVER NRN AND WRN AREAS. IF PRECIP GETS AN EARLY ENOUGH START, IT COULD START OFF AS THE WINTRY VARIETY WITH TEMPS AOB FREEZING. HOWEVER, CONFIDENCE IS LOW ON ONSET TIME THIS FAR OUT. WITH SUCH A STRONG LOW DEVELOPING, AND PULLING IN GULF MOISTURE, A SLOWER AND WARMER SYS IS GENERALLY EXPECTED, SO THIS WOULD BE MORE SUPPORTIVE OF THE GFS/CMC, BUT FOR NOW WILL JUST KEEP SOME LOW POPS. THE GUID THEN KEEPS MOST OF THE DAYTIME HOURS OF SUN DRY IN THE WARM SECTOR BEFORE THE LOW REALLY STARTS TO WIND UP CLOSER TO SUN EVE NR THE GRTLKS AND THE CDFNT APPROACHED FROM THE W. THE HIGHEST POPS LOOK TO BE SUN EVE/NIGHT WITH A FIRST CDFT. THERE CUD BE SOME HVY RAIN AS WELL. TEMPS WILL BE WARM ENOUGH EVERYWHERE THAT THE BULK OF THE PRECIP WILL BE PLAIN RAIN. BEHIND THIS FRONT, THERE COULD BE SOME LINGERING RAIN INTO MON BEFORE A SECONDARY CFP OCCURS MON NIGHT ORE EARLY TUE AND ENDS THE RAIN CHCS AND RE- ESTABLISHES A TROF OVER THE CONUS. THERE ARE STILL SOME DIFFS TO BE IRONED OUT IN THE MDLS BUT THERE ARE 4 TO 5 DAYS FOR THIS TO OCCUR. TEMPS WILL WARM FOR THU, THEN DROP A BIT FRI AND SAT BEHIND THE FIRST CFP. THEN THEY WILL SOAR SUN AND MON IN STRONG SWLY FLOW. THERE COULD BE CLOSE TO A 30 DEGREE TEMPERATURE RISE BETWEEN FRI AND MON! && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR TODAY AND TONIGHT. THE GUSTY NW WINDS CONTINUE TO DIMINISH OVERNIGHT. A TEMPO GROUP WAS INCLUDED IN THE 06Z TAFS TO CAPTURE OCCASIONAL GUSTS TO NEAR 20 KT THRU DAYBREAK FOR THE PHILLY AND SOUTHERN NJ TERMINALS. WLY WINDS BECOME SWLY THIS AFTN AND EVEN SLY AROUND SUNSET. BY 06Z THURSDAY, SW WINDS ALOFT STRENGTHEN TO ABOUT 50 KT AT 3000 FT ABOVE THE SURFACE. WHILE NOTABLE, MODEL OUTPUT DOES NOT INDICATE IT QUITE MEETING LLWS CRITERIA. OUTLOOK... THU...VFR. CFP THU AFTN MAY RESULT IN WLY WIND GUSTS 25-30 KTS. MDT CONFIDENCE. FRI THRU SAT...VFR. HIGH PRESSURE. HIGH CONFIDENCE. SUN...LOW PRES APPROACHES FROM THE W WHICH WILL BRING RAIN TO THE AREA. MVFR POSSIBLE IN LOW CIGS AND VSBYS WITH RAIN...ESPECIALLY IN THE LATER PART OF THE DAY. LOW CONFIDENCE ON TIMING. && .MARINE...
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630 AM UPDATE...GALE WARNING WAS CANCELED AND REPLACED BY A SMALL CRAFT ADVISORY AS WINDS GRADUALLY WEAKEN. THE SMALL CRAFT ADVISORY IS IN EFFECT THRU 11 AM THIS MORNING. PREVIOUS DISCUSSION...AS OF 3 AM, WESTERLY WINDS ARE STILL GUSTING AROUND 35 KT AT NEARBY BUOYS 44025/65 AND AT THE CAPE MAY WX FLOW STATION. WINDS ARE FORECAST TO WEAKEN OVER THE NEXT FEW HOURS, SO THE CURRENT 6 AM GALE WARNING EXPIRATION TIME SHOULD STILL WORK. A SCA WILL BE ISSUED TO COVER THE EARLY AND MID MORNING. NO HEADLINES ARE EXPECTED FOR THIS AFTERNOON. WINDS BACK OUT OF THE SOUTHWEST AND THEN STRENGTHEN TONIGHT. ONCE THE MORNING HEADLINES EXPIRE, A SCA WILL LIKELY BE ISSUED FOR TONIGHT FOR THE COASTAL ATLANTIC WATERS AND AT LEAST THE LOWER DELAWARE BAY (BOTH WINDS AND SEAS). THERE IS ALSO CONCERN FOR GALES TONIGHT OVER THE COASTAL ATLANTIC WATERS. SOUTHWEST FLOW ARE NOT TYPICALLY ASSOCIATED WITH FAVORABLE MIXING SETUP. HOWEVER, THE MODERATING AIRMASS ABOVE THE RELATIVELY WARM OCEAN MAY STILL BE COLD ENOUGH TO SUPPORT MIXING OF 35 KT WINDS ALOFT DOWN TO THE SURFACE. WILL LET THE DAY SHIFT ANALYZE THE NEWEST SET OF GUIDANCE BEFORE DECIDING WHICH MARINE HEADLINE IS BEST SUITED FOR TONIGHT. OUTLOOK... THU AND FRI...SCA LIKELY IN INCREASING SW FLOW AHEAD OF A CFP AND AGAIN BEHIND THE FRONT IN W-NW WINDS...GENERALLY 25-30 KT. ALSO, CANNOT RULE OUT A PERIOD OF GALES LATE ON THU INTO EARLY FRI. FRIDAY NIGHT THROUGH SUNDAY...SUB-SCA CONDITIONS ARE EXPECTED.
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&& .CLIMATE... BELOW IS A LISTING OF RECORD LOW TEMPERATURES AND THE YEAR OF OCCURRENCE FOR TODAY, NOVEMBER 19 FOR OUR EIGHT CLIMATE SITES. RECORD LOWS FOR THIS MORNING: ACY 18 1936 PHL 20 1936 ILG 15 1936 ABE 11 1924 TTN 17 1936 GED 20 1959 RDG 18 1936 MPO 10 1933 ADDITIONALLY, NEAR RECORD LOW MAX TEMPERATURES ARE FORECAST FOR TODAY. 11/19 RECORD LOW MAX TEMPS: 11/19 FORECAST MAX TEMPS: ACY 35 1951 ACY 35 PHL 35 1951 PHL 33 ILG 34 1951 ILG 34 ABE 32 1951 ABE 30 GED 38 2008 GED 35 MPO 24 1951 MPO 24 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ430- 431-450>455. && $$ SYNOPSIS...NIERENBERG NEAR TERM...GAINES/KLEIN SHORT TERM...KLEIN LONG TERM...NIERENBERG AVIATION...KLEIN/NIERENBERG MARINE...KLEIN/NIERENBERG CLIMATE...

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