Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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643 FXUS61 KPHI 181146 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 646 AM EST Wed Jan 18 2017 .SYNOPSIS... Low pressure forming near the New Jersey coast will intensify eastward, to the south of Cape Cod today. High pressure then builds across the Eastern Seaboard Thursday. Weak low pressure will pass through the region this weekend, and then a much larger and stronger system will impact the area early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Early this morning...LSR`s posted for ice. So far no further reports other than a final expected for KMPO during mid morning. Spotty light freezing rain and drizzle persists at or above 1000 feet in northern Monroe and northern Sussex counties and even down into the region above 1800 feet in Carbon County. Today after 8 am...Mostly cloudy with scattered or widely separated showers through early afternoon (drizzle north as well) as a sharp trough aloft passes southeast through the mid Atlantic states. Cool north but becoming milder south during the afternoon as skies brighten a bit toward sunset. North winds near and north of I-78 while a northwest wind becomes gusty 20-25 MPH during the afternoon s NJ and Philly area southward through the Delmarva. Max temps 5 to 10F warmer than normal north and around 10F warmer than normal south. Fcst basis was a 50 50 blend of the 00z/18 NAM/GFS mos guidance. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... Clearing far south though it should remain mostly cloudy elsewhere. Temps 10 to 15 degrees above normal. Northwest wind. Confidence on temps radiating a bit is below average and the lows may be forecast too low. Fcst basis was a 50 50 blend of the 00z/18 NAM/GFS mos guidance. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Our warm and wet pd continues into the extendd. Thu looks to psbly be the nicest day of the pd, with more sun than clouds and temps around or n of 50 degrees in many areas with dry conds under high pres. The high will move ewd Thu night into Fri and wk low pres will bring a shot of shwrs thru by Fri aftn. This shud be a relatively quick shot from aftn into erly eve. Then wk high pres will move back in for later Fri into Sat bringing a return to dry wx. By Sun, a large area of low pres will move out of the srn plains twd the sern states and mid-Atlc. There are still some timing diffs wrt the onset of rain. The GFS is slower movg the precip in than the ECMWF. THe GFS would keep most of SUn dry, not bringing rain in until the aftn, while the EC would bring rain in durg the mrng, especially over srn areas. The CMC is more supportive of the slower soln, so for now will just keep some low pops erly and trend pops upward durg the aftn, but this is a lower than average confidence fcst and Saturday certainly looks to be the better of the two weekend days. The aforementioned low will move to our sw on Mon and Mon is likely to be the wettest day. The guid differs on where the heaviest and steadiest rain may set up, but Mon could end up being a washout, at least for portions of the area. By Tue, the low should be pulling away. The ECMWF ends the precip sooner, while the GFS lingers it somewhat thru the day. However, pops shud at least be decreasing from s to n, if not completely over. Temps look to be much abv nrml thru the pd, about 10 to 15 degrees. With the exception of the highest elevations of the Poconos Mon mrng, all precip that falls durg this pd shud be plain rain. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...General IFR conditions at sunrise will gradually improve to MVFR cigs during midday with vsby improving to VFR as north to northwest winds gradually increase with northwest gusts vcnty KACY, KPHL, KMIV and KILG of 20-25 kt during the afternoon. Scattered morning showers/drizzle will end early afternoon. Tonight...Probably VFR bkn-ovc cigs aoa 3500 ft though it may scatter out at KPHL southward, especially after 06z. Light northwest wind. OUTLOOK... Thu through Fri mrng...VFR. High pres. High confidence. Fri aftn thru Fri night...Sub-VFR conds psbl in -RA. Mdt confidence. Sat through Sun. Mainly VFR. High confidence VFR Sat. Lower confidence VFR Sun, especially s as RA is psbl. && .MARINE... A short period of SCA northwest winds expected for this afternoon with winds subsiding early tonight. OUTLOOK... Thu through Sun...Sub-SCA conds expected. Sun night through Mon night...Easterly flow 20-30 KT. SCA conds likely, with gale force winds possible on Mon, mainly on the ocean waters. Tue...Wind shud subside below SCA conds, but seas will remain elevated. && .Climate... PHL continues to project a very warm month, anywhere from 5 to 6 degrees above normal and ranking anywhere from 10th to 17th warmest in the POR dating back to 1874. No substantial cool anticipated until around the 27th. most other stations in our area should follow suit except only maybe 3 above normal at KMPO. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Freezing Rain Advisory until 7 AM EST this morning for PAZ055. NJ...Freezing Rain Advisory until 7 AM EST this morning for NJZ001. DE...None. MD...None. MARINE...Small Craft Advisory from 1 PM this afternoon to 9 PM EST this evening for ANZ430-431-452>455. && $$ Synopsis...Nierenberg Near Term...Drag 646 Short Term...Drag Long Term...Nierenberg Aviation...Drag/Nierenberg Marine...Drag/Nierenberg 646 Climate...Drag 646 is the U.S. government's official web portal to all federal, state and local government web resources and services.