Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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817 FXUS61 KPHI 272046 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 446 PM EDT Thu Apr 27 2017 .SYNOPSIS... A cold front will move across the area tonight into Friday morning. A backdoor cold front will move across the area Saturday into Saturday night. This front will remain to our south on Sunday, then return as a warm front on Sunday night. Another cold front is expected on Monday night, with a secondary front or surface trough Tuesday. Another cold front is possible Wednesday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... The majority of the low clouds from this morning have since eroded, with the exceptions being portions of the NJ coastline due to persistent low level southeasterly flow and across the terrain of NEPA and NWNJ. Continued erosion is expected through the remainder of the afternoon. At the same time mid to high clouds will also be streaming overhead out ahead of a low pressure system ejecting through the Great Lakes. Highs this afternoon will range from the low 70s across NEPA/NWNJ to low 80s south, except stuck in the 60s along the immediate shoreline. Tonight, the trailing cold front associated with Great Lakes low will push eastward, crossing the area between midnight and sunrise. There will be some scattered showers along the front, along with the possibility of a few elevated thunderstorms. Not expecting any severe threat as any instability will not be surface based. Models also showing the potential for redevelopment of some low clouds and fog potential across portions of northern NJ and into northeastern PA. Elsewhere, played down fog threat as low level southerly flow out ahead of the front should inhibit more widespread formation. Lows drop into the mid 50s to low 60s by morning. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/... Warm and mostly sunny day expected once front clears the region on Friday. Should see highs at or above 80 degrees for most locations, except along the immediate shoreline and the higher elevations of the Poconos. A frontal wave will be moving along a stationary front off to the northwest of the area late Friday night and into Saturday morning. This may touch off a few showers or an isolated thunderstorm Friday night into Saturday morning. As it moves northeastward into New England, strong surface high pressure will build in behind it, pushing the frontal boundary southward towards and through the area Saturday night. Out ahead of it though on Saturday, expecting warm temperatures with highs in the 80s along with the chance for a few showers/thunderstorms. SPC has placed part of the area in Marginal Risk for severe thunderstorms on Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Much of the area will then be on the cool side of the boundary on Sunday with northeast low level flow. This will keep temperatures much cooler than on Saturday with highs from 65-70F for most locations, except across portions of Delaware and eastern Maryland where they may try to remain on the warmer side of the boundary. Uncertainty still remains on its position. Chances for additional showers also exist, but thunder threat much lower with stable low levels. Front will then traverse back northward over the region Sunday night into Monday out ahead of a low pressure system pushing through the Great Lakes. This will lead to the redevelopment of southerly flow and rebounding temperatures. Highs Monday should reach back into the 70s to near 80F. The cold front then pushes across the area late Monday and Monday night with showers and possible thunderstorms. Cyclonic flow aloft develops behind the front for Tuesday and Wednesday with a few secondary cold fronts possible. Most areas remain dry, but some instability showers in the colder air aloft are possible, especially across the Poconos and NW NJ. Highs from the 60s to low 70s and lows in the 40s and 50s. The next organized system will then be developing across the lower Mississippi Valley during the middle of next week and will push towards the region by late in the week with the next chance of more widespread precipitation. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. This Afternoon...Lingering IFR at ACY and MVFR at TTN will gradually improve to VFR during the remainder of the afternoon hours. Winds generally S/SE around 10 knots, with some gusts to 15 knots. Tonight...After 03Z, low clouds may move back in over the region, mainly ACY/ABE/TTN, although potential does exist at other sites. In addition, showers and isolated thunderstorms will approach from the west. There is low confidence though on if individual TAF sites will be affected and the timing. Southerly winds tonight shift west late after frontal passage. Friday...VFR develops at all TAF sites with west/northwest winds. OUTLOOK... Friday night...VFR early. Patchy fog and low CIGS may develop overnight. Saturday...Becoming VFR during the morning, although chances exist for a few showers and thunderstorms. Conditions may temporarily be reduced with any showers/storms. Saturday night-Sunday night...Low clouds and fog may develop overnight Saturday and continue into Sunday night leading to reduced conditions. Small chance of showers and thunderstorms. Conditions may temporarily be reduced with any showers. Monday...Low conditions in the morning, becoming VFR during the day. A chance of showers thunderstorms during the day, with more likely showers and thunderstorms overnight. Lower conditions possible during the day with any showers or storms, more likely lower conditions overnight. Gusty southwest winds around 25 knots. && .MARINE... Elevated seas are expected to continue today and tonight on the Atlantic Coastal waters, generally ranging from 5 to 6 feet. A few gusts near or above 20 kt are possible this evening. OUTLOOK... Friday...Winds expected to remain below advisory levels, but seas may remain elevated to advisory levels. Friday night-Sunday night...Seas may approach 5 feet at times, and winds may gust near 20 knots, but conditions expected to remain below advisory levels. Monday...Winds likely to gust 25-30 knots, and seas likely to exceed 5 feet as well leading to Small Craft Advisory conditions. A period of Gale conditions is also possible. && .TIDES/COASTAL FLOODING... Though some of the guidance is depicting minor coastal flooding with the evening high tides today and tomorrow, we are not expecting any coastal flooding as astronomical tides will start to decrease, and by tonight, winds will be shifting to off shore. && .CLIMATE...
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**Record or number 2 warmest April on record expected** Presuming our forecast temps these last 4 days of April are accurate, we are assured of a top 2 warmest April on record in much of our forecast area. Sunday is probably the critical day for determining record or not. Below: April projected within the top April average temps, the normal for April and the period of record (POR). This includes todays high and low temperatures through 4 PM. PHL normal 54.0 POR 1874 59.4 1994 59.4 2017? projected tied warmest ever 58.5 1921 58.4 2010 57.9 1941 ABE normal 49.9 POR 1922 56.8 projecting record 56.4 1941 54.7 1994 ACY normal 51.7 POR 1874 57.2 projecting record 56.3 2010 56.1 2011
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT Friday for ANZ450>455. && $$ Synopsis...99 Near Term...Johnson/99 Short Term...99 Long Term...99 Aviation...99 Marine...99 Tides/Coastal Flooding...99 Climate...Drag

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