Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 310420 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1220 AM EDT WED AUG 31 2016 .SYNOPSIS...
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A cold front in the Great Lakes will slowly pass through our area tonight and Thursday morning. High pressure will build southeast into the Great Lakes and New England Friday through Sunday. Tropical depression nine, currently in the Gulf, is expected to move northeast along the southeast USA coast Friday and will need to be monitored thereafter as it continues northeast. High pressure becomes dominant along the Appalachians early next week.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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Early this morning...some cloudiness and patchy dense fog expected. humid. light near calm wind. Today...mostly sunny this morning, then partly sunny this afternoon. Hot. wind becoming south to southwest with scattered afternoon gusts around 15 mph. showers and scattered gusty thunderstorms could move east northeastward into the Poconos late in the day. forecasting 90-93 in PHL today. EC has been constantly warmer with its 18z 2m temps (88-89) and the 00z/31 GFS 2m has 89. Am comfortable fcstg 92-93F. Thats day 6 and the last of this heat wave for PHl and ESN but not last of the season.
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&& .SHORT TERM /WEDNESDAY NIGHT/...
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Tonight...As a cold front sags southward and the winds to its north probably turns north, convergence will increase considerably and so despite this cfp being in the middle of the night, am expecting an active night with groups of heavy showers in the pwat of 1.8" and possibly isolated thunderstorms.
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&& .LONG TERM /THURSDAY THROUGH TUESDAY/...
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Thursday: Showers and isolated thunderstorms should end across the southern portions of the region during the day Thursday. QPF of a quarter to half inch seems reasonable as well, with the SREF, WPC and the WRF NMM/ARW models used for the QPF forecast. High temperatures Thursday will likely end up a few degrees below MOS guidance given the cloudcover with highs around 80 in most places. Thursday night through Tuesday: High pressure will build eastward into New England and remain in place or slowly shift east through early next week. Temperatures look to be several degrees cooler through the weekend, with a warming trend early next week. If it were just this high pressure system as a potential influence on our weather, sunny skies with a dry holiday weekend will occur. However, TD 9 is a potential factor as well. The GFS, GEFS, UKMET and Canadian models all have this feature slowly tracking up the coast, stalling it to our south or even turning back to the northwest. This would increase cloudcover, winds and the prospects for rain as you get closer to the coast. The ECMWF up till the 30/12 run has been fairly consistent with having TD 9 get carried out to sea with the trough which brings a cold front through on Thursday. Overall, a lot of uncertainty is present around the weekend time period. Given the building ridge this weekend the potential is present for this system to get trapped somewhere close to our region. However, will not commit fully to the new trend yet given it is only set of model runs.
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&& .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through 12z...VFR sct-bkn clouds mainly above 5000 ft with patchy mvfr cigs in NJ. Local IFR visibilities in fog over the countryside. Winds mostly light and variable to locally calm. Today...Any local fog dissipates by 12z, otherwise VFR. South- southwest winds increase to 5-10 knots, however becoming southeast at ACY in the afternoon. A cold front will approach later in the day. It appears that the showers/thunderstorms remain to our north and west, however some may approach ABE and RDG after 21z. Tonight...VFR to start, with some MVFR restrictions possibile in any heavier showers or isolated thunderstorms. Southwest winds around 10 knots shifting to light north. chance IFR cigs parts of the area after 06z/01. OUTLOOK... Thursday: Mainly VFR, with some MVFR restrictions possibile in any heavier showers or isolated thunderstorms. Thursday night through Friday night: VFR. Northerly winds around 10 knots. Saturday and Sunday: Considerable uncertainty in this period of the forecast due to currently TD 9. If TD 9 stays offshore (currently most likely) VFR throughout with winds generally under 15 knots. Lower ceilings and higher winds if we see impacts from TD 9, KACY and KMIV have highest chances currently.
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&& .MARINE...
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No marine headlines anticipated through tonight. Easterly long period (12 second) well modeled swell of 3 feet persists through tonight on the Atlantic waters (Gaston). Otherwise add a wind wave of a foot or so and we have 3-4 ft on the Atlantic waters and around a foot on DE Bay. Southeast to south wind of 5 to 15 kt becomes light north from north to south toward dawn Thursday. showers and isolated thunderstorms later tonight (Wednesday night). Water temperatures are generally in the 70s, which is above normal. OUTLOOK... Thursday through Sunday: Seas gradually building heading into the weekend. Seas of a couple of feet and northerly winds at or under 15 knots through Friday. Considerable uncertainty with how high the seas get in relation to the track of TD9 for the weekend. Seas right now look to be at or above SCA criteria from Friday night from Sunday. Northeasterly SCA gusts are possibile in this timeframe as well. RIP CURRENTS... Through Wednesday...A 3 to 4 foot long period swell and an onshore wind component is resulting in rough surf conditions. This is expected to continue and therefore the rip current risk remains at moderate. A Beach Hazards Statement remains in effect through Wednesday that continues to highlight this hazard. Thursday: Rip current risk probably eases back to low. Friday-Monday: Rip current risk increases with cool boundary layer wind transfer as high pressure develops to our north, with an ensembled fairly extensive broad easterly fetch developing south of New England. Likely to be moderate or higher depending on the track and intensity of TD9. This system needs to be monitored for Sunday- Monday impact. In terms of safety, follow the advice of local lifeguards who will be observing the waves and swimmers. There may be some beach closures, all dependent on the reality that develops. This is not a time to swim on your own without lifeguard presence. Additionally, waders are cautioned not to turn their backs to the waves when coming out of the water. Wave knock down can result in upper torso injury (dislocations/spinal cord injuries).
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&& .TIDES/COASTAL FLOODING...
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Some minor tidal flooding is possible late this week and the weekend with the high tide cycles. However, this is highly dependent on the track of TD 9. A track closer to the coast would increase the threat.
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&& .CLIMATE...
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This section is up to date through 1210 AM Today-Wednesday August 31. A top 4 warmest August most of our forecast area with record monthly warmth at PHL. A top 3 warmest June-July-August for Philadelphia, Allentown and possibly Atlantic City. Philadelphia will establish its warmest August on record (dating back to 1874). More than 4 degrees above normal. This Philadelphia August ranking includes our forecast temps (SFT specific values) through the 31st. The 30 year normal is 76.6 Records date back to 1874. 1. ~81.0 2016 2. 79.9 1980 3. 79.8 2001 and 1995 August will equal its record of 17, 90F days. The record of 17 was set in 1995. The mean for the month is only 5. Allentown will rank #2 warmest August. Records date back to 1922. Normal is 71.7 and we are projecting a positive departure of around 5 degrees. 1. 78.2 1980 2. 76.5 or 75.6 2016 3. 76.0 1937 Atlantic City records date back to 1874. The August monthly normal is 74.4 and we`re projecting a positive departure of nearly 4 degrees. As it stands, Atlantic City will rank #1 warmest August. 1. 78.2 2016 2. 77.9 2005 Seasonal: This summer 2016 for Philadelphia will be the 2nd warmest June-July-August (JJA) in the period of record dating back to 1874. 1. 79.6 2010 2. 78.8 2016 3. 78.6 1995 4. 78.3 1994 Allentown seasonal avg is projecting 75.0 or a ranking of around #2 in the por. 1 75.3 1949 2 75.0 2016 3 74.6 2005 and 1980 Atlantic City seasonal average is projecting 75.8...4th warmest in the por. 1. 77.5 2010 2. 77.0 2011 3. 75.9 2005 4. 75.8 2016 5. 75.5 2008 90 degree days through the 30th. season mean Aug Aug Aug Season mean rer rer ABE 33 17 12 4 16-1980 41-1966 ACY 28 10 11 3 11-2010 46-2010 PHL 40 21 16 5 17-1995 55-2010 ILG 34 20 15 5 23-1895 59-1895 Rainfall: Some uncertainty exists regarding additional rainfall in August, so this part of the climate is stated with caution. Presuming no further measurable rain this month of August...the current ACY value of 1.10 should rank the 6th driest August on record, after a 6th wettest July. For Philadelphia, the June-August seasonal total of 7.45 inches is so far, the 12th driest summer...again this presumes no further measurable rain in August.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...Beach Hazards Statement through Wednesday evening for NJZ014- 024>026. DE...Beach Hazards Statement through Wednesday evening for DEZ004. MD...None. MARINE...None. && $$ Synopsis...Gaines Near Term...Drag/Gorse 1220a Short Term...Drag/Gorse/MPS 1220a Long Term...Gaines Aviation...Drag/Gaines/Gorse 1220a Marine...Drag/Gaines/Gorse/MPS 1220a Tides/Coastal Flooding... Climate...1220a

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