Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 291948 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 348 PM EDT MON AUG 29 2016 .SYNOPSIS...
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A frontal boundary extended from around Cape Cod, across the waters off Long Island to central New Jersey and southeastern Pennsylvania at mid afternoon. The front will slowly dissipate as it drifts southward. Weak high pressure is forecast to build across New York and New England from tonight into Tuesday. Tropical Depression Eight is expected to pass well to our southeast on Wednesday as a strong cold front approaches from the northwest. The front is anticipated to pass through our region early on Thursday followed by high pressure for Friday into the upcoming holiday weekend.
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&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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A weak cold front will move offshore tonight with high pressure building southeast behind the front into the region. Winds be from the northwest tonight behind the cold front but will become light in the evening. With mostly clear skies and an even drier air mass working into the region it should be a favorable setup for radiational cooling but not fog. Given the players on the field tonight, opted to go a couple of degrees cooler than what most of the MOS guidance has tonight, particularly the ECMWF. In rural areas across northern NJ and PA along with the Pine Barrens temperatures should fall fairly quickly with lows in the 50`s and low 60`s for many. Lows should end up a few degrees warmer in the urban corridor.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
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Tomorrow, high pressure will move eastward through the region allowing for another sunny late summer day. Temperatures will rebound quickly with another run at 90 likely for Philly. Winds will likely be light and variable, under 10 mph throughout most of the day and not much potential for mixing is showing up on soundings. Winds will be more of an easterly direction from Philadelphia to the southeast resulting in an onshore flow another risky day for swimming in the ocean (see rip current section).
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&& .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
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The forecast continues to keep Tropical Depression Eight well enough to our southeast on Wednesday as not to impact our weather. A strong cold front is expected to extend from southern Ontario to the middle Mississippi River Valley on Wednesday morning. It should reach central New York and western Pennsylvania late in the day. We will continue to mention a chance of showers and thunderstorms in our northwestern counties for Wednesday afternoon. The potential for scattered showers and thunderstorms will overspread the remainder of our forecast area on Wednesday night. The front is expected to work its way though our region early on Thursday. The guidance continues to linger showers through the morning hours, especially on the coastal plain. Maximum temperatures on Thursday are anticipated to be in the 70s in the elevated terrain of the Poconos and northwestern New Jersey and in the lower and middle 80s elsewhere. Dew point readings should drop into the lower 60s and 50s. High pressure is forecast to build from Ontario and the Great Lakes on Thursday to the northeastern states on Saturday before drifting off the coast. The air mass will be noticeably cooler and less humid than the one that it will be replacing. We will need to keep an eye on the tropical activity to our south and east over the weekend.
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&& .AVIATION /20Z MONDAY THROUGH SATURDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. VFR throughout the TAF period with some scattered mid and high level clouds from time to time. Northwest winds around 10 knots becoming light and variable tonight and staying under 10 knots tomorrow. Winds shifting to easterly from Philadelphia and points SE on Tuesday. Little to no chance of fog formation at any TAF site. OUTLOOK... Tuesday night and Wednesday morning...Mainly VFR. Late night and early morning visibility restrictions are possible. Wednesday afternoon into Wednesday night...Mainly VFR. However, there is a chance of showers and thunderstorm. Thursday...Mainly VFR with a chance of showers. Thursday night through Saturday...Mainly VFR.
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&& .MARINE...
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Wave heights close to three feet will likely build slowly to between three and four feet given the onshore flow by tomorrow. Winds will start from the west and northwest tonight before becoming more easterly on Tuesday, around 10 knots. OUTLOOK... Tuesday night through Saturday...No marine headlines are anticipated. However, long period swells may create rough conditions in and around the inlets along the coasts of New Jersey and Delaware. RIP CURRENTS... The rip current risk is moderate for the remainder of today. This is largely in part due to swells from tropical systems offshore and well out to sea. Long periods of around 13 seconds have been predominant today and will likely continue to be through tomorrow. With an onshore flow tomorrow and slightly higher seas, another moderate risk day looks likely. If the onshore easterly winds increase a bit more than forecasted or the waveheights are slightly higher than forecasted conditions then may be favorable for a high risk. Wednesday: GFS and tropical modeled swell/period wave groups strongly suggest a moderate risk for the formation of dangerous rip currents continues. In terms of safety, follow the advice of local lifeguards who will be observing. 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). A beach hazards statement was issued to alert for the rough surf for this week into the coming weekend, this in part based on NHCs outlook compared with the GFS/EC operational cycles.
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&& .CLIMATE...
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This section is up to date through 435 AM Today-Monday August 29. Today`s data have yet to be finalized. A top 4 warmest August appears assured most of our forecast area with record monthly warmth likely 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 Regarding whether August can tie its record of 17 90F days. Its possible but not probable. Foresee an additional 2 to 3 more 90 degree days to add onto the 13 we have so far this month. The record of 17 was set in 1995. The mean for the month is only 5. Tuesday is the possible day for breaking a modest heat wave and eliminating a chance at a record equaling 17, 90 degree days in August. 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. 76.6 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 or #2 warmest August with very little chance of slipping to #3. The forecast and climate for Atlantic City has greater variability than Allentown and Philadelphia due to proximity to water on sea breeze days and notable radiational cooling on some nights. 1. 78.2 2016 2. 77.9 2005 3. 77.1 2009 Seasonal: This summer 2016 for Philadelphia will probably 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 28th. season mean Aug Aug Aug Season mean rer rer abe 33 17 12 4 16-1980 41-1966 acy 27 10 10 3 11-2010 46-2010 phl 38 21 14 5 17-1995 55-2010 ilg 32 20 13 5 23-1895 59-1895 Rainfall: Considerable 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 would 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...
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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.
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&& $$ Synopsis...Iovino Near Term...Gaines Short Term...Gaines Long Term...Iovino Aviation...Gaines/Iovino Marine...Drag/Gaines/Iovino Climate...Drag

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