Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 202307 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 607 PM EST Tue Feb 20 2018 .SYNOPSIS... Bermuda high pressure slowly drifts to the south and east tonight through Wednesday. A cold front will then approach late Wednesday and pass through the region Wednesday night, then becomes nearly stationary over the Mid-Atlantic region. Several waves of low pressure will pass along this boundary through the weekend. High pressure returns for the start of the new work week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A good start this evening, the a return to the maritime pattern with low clouds, drizzle and fog developing. We will probably have some dense fog in a few areas, but will hold on any flags attm deferring to the evening shift. Lows tonight, very mild, with upper 40s across the north and low/mid 50s elsewhere. Light winds after sunset. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... Wednesday will likely start much the same way as did Tuesday. That is, plenty of low clouds, fog and some drizzle across the region. Slow improvement though the morning and then a return to partly/mostly sunny skies during the afternoon. An approaching cold front may trigger a few showers N/W in the afternoon. We will only have some chc pops for this with the fcst with the dynamics not looking too strong with it. Temperatures, once again, in record territory with highs in the low/mid 70s in most areas with some 60s across the far north. Colder right along the shore however. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Although the record setting warmth will depart Wednesday night, there will still be a prolonged period of above normal temperatures for the Long Term. Cold front works its way south through the region Wednesday night and becomes nearly stationary along the Mid-Atlantic by Thursday morning. The region then becomes situated between cold high pressure to the north and warm high pressure to the south. Temperatures should rise and fall with each passing low, but the areas mainly impacted by the cold should be generally north of I-78 through the end of the work week. Showers taper off in the evening, and then return late Wednesday night as weak low pressure forms over the Gulf Coast states and lifts to the north and east. Behind the front, temperatures drop into the 30s north and west of the Fall Line, and lows will be in the 40s across the Coastal Plain of NJ, southeast PA, and into the Delmarva. As precipitation develops with the next system, temperatures should be cold enough in the Poconos and far northwest NJ to allow for a period of mixed frozen precip, mainly rain, freezing rain, and sleet, late Wednesday night and into Thursday morning. For the rest of the region, precip should mainly stay as rain, as surface temperatures should stay above freezing. By Thursday afternoon, precip should be all rain throughout, and then tapers off by Thursday evening. The next low develops Thursday night and approaches on Friday. A good period of mixed frozen precip looks to develop across northern areas north and west of the Fall Line Thursday night and eventually changes to plain rain by Friday afternoon. Upper trough then approaches for the west this weekend, and stronger low pressure will impact the region with more widespread rain through Sunday. Conditions dry out on Monday as high pressure builds in from the west. Temperatures will generally be above normal levels during this time, but it looks as if it will be quite warm, though wet, over the weekend. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Another challenging fcst with regards to what time the lower conditions will arrive. Went along with the latest guidance and generally went 01z thru 03z for a return to IFR/LIFR overnight. Drizzle and for will again be widespread overnight. Winds will be light mostly SW or S. Wednesday...IFR/LIFR widespread with fog and drizzle during the morning...then improvement in the 16Z thru 18Z time frame. Again, low confid in improvement timing as was the case yesterday. Confidence: Average. OUTLOOK... Wednesday night...Scattered showers and patchy fog possible with sub-VFR conditions. Winds shift from SW to N. Confidence: Average. Thursday...Sub-VFR conditions possible in rain. NE winds 10-15 kt. Confidence: Average. Thursday night...Sub-VFR conditions possible in scattered showers. Mixed frozen precip in rain and sleet possible at KRDG/KABE/KTTN/KPNE late. Confidence: Below average. Friday through Saturday...Sub-VFR conditions in periods of rain. Confidence: Below average. && .MARINE...
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The main hazard tonight and into Wednesday morning will continue to be fog. A Marine Dense Fog Advisory remains in effect into Wednesday. Winds tonight and Wednesday will be south to southwest at 5 to 10 knots for the most part. Water temperatures 40 to 45 degrees. Winds and seas are expected to stay below small craft advisory criteria tonight and tomorrow. OUTLOOK... Wednesday night...Sub-SCA conditions expected. SW winds turning NW overnight. Thursday through Friday...SCA conditions possible on the ocean waters. Saturday...Sub-SCA conditions anticipated. Sunday...SCA conditions possible.
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&& .CLIMATE...
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The following high temperature records were set today: Atlantic City...73 Philadelphia...72 Wilmington...75 Georgetown...73 Mount Pocono...66 Trenton...71 Please check the following list for the old records. Additional high temperature records are likely this afternoon and Wednesday. Tuesday, February 20: Atlantic City...70 in 1930 Philadelphia....70 in 1939 Wilmington......71 in 1930 Allentown.......68 in 1930 Trenton.........70 in 1930 Georgetown......68 in 2002 Mount Pocono....59 in 1930 Reading.........72 in 1930 Wednesday, February 21: Atlantic City...74 in 1930 Philadelphia....72 in 1930 Wilmington......70 in 1953 Allentown.......67 in 1953 Trenton.........70 in 1930 Georgetown......71 in 2014 Mount Pocono....60 in 1930 Reading.........71 in 1930 A record warm minimum temperature may be set for Atlantic City today. The current record is 44 in 1949. We will have to wait and see how low the temperature gets through the evening hours. The low so far today has been 52 degrees. The following are the record warm minimum temperatures for Wednesday, all which should be exceeded. ABE 46-1981 ACY 49-1954 PHL 49-2002 ILG 47-2002 RDG 48-1930 TTN 48-2002 The all time February max temps may be approached on Wednesday at ILG, TTN, GED RDG MPO. All the all time monthly max`s are listed below: ACY 77 2/25/30 PHL 79 2/25/30 ILG 78 2/24/85 ABE 77 2/24/17 TTN 76 2/25/30 GED 77 2/25/17 RDG 77 2/24/17 MPO 70 2/25/30 Our expectation is that ACY will exceed the previous all time record rainfall for February, by the end of the weekend. The record is 6.50 inches in 2010. #2 is 1958 with 5.98 inches. And...adding only half an inch to PHL and ILG will put both locations in the top 9 ranking for Feb rainfall. Have rechecked the monthly projection at PHL and the avg temp continues at 41.0 or 5.3F above avg which is 8th warmest on record, if it holds. Add or subtract a degree to the average/departure and the ranking changes from 3rd to 11th. The forecast 5.3F departure is ~2f warmer than the current departure. I`d expect similar for the rest of our area...a bit less in the north which will have better chances for colder air, and a bit more warming in the south where the positive departure as of yesterday was already 5F above normal, heading for 7+. So all in all it appears we`re heading for a top 10 warmest February. Last year was the warmest on record, a whopping 3+F degrees warmer than our current projection.
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&& .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...None. NJ...None. DE...None. MD...None. MARINE...Dense Fog Advisory until 10 AM EST Wednesday for ANZ430-431- 450>455.
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&& $$ Synopsis...MPS Near Term...O`Hara Short Term...O`Hara Long Term...MPS Aviation...MPS/O`Hara Marine...MPS/O`Hara Climate...

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