Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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732 FXUS61 KPHI 222237 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 637 PM EDT FRI JUL 22 2016 .SYNOPSIS...
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A weak front is expected to move into the area late tonight into Saturday. High pressure will then build in for Sunday through Tuesday, however another weak front arrives late Monday into Tuesday before stalling nearby Wednesday and Thursday.
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&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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A surface trough remains across the area. While there is instability, the water vapor imagery and some LAPS soundings clearly show rather dry air in the mid levels (especially for the northern half of the forecast area). This in combination with much of our area being south of a mid level speed max is keeping the shear on the lower side. There is some convection in southeastern New York into portions of northeastern Pennsylvania, however it looks like anything that can develop or move southeastward is mostly isolated and across the far northern zones. The visible satellite imagery also shows some cumulus, some of which were showing signs of more vertical growth earlier, but overall it has mostly struggled. The mid level wind max is forecast to settle southward a bit through the overnight, but not quite sure if this is enough to keep or develop some convection beyond mid evening. This update lowered the pops some and removed the enhanced wording. The hourly temperature, dew point and wind grids were adjusted based on the latest observations, then the LAV/LAMP guidance was blended in.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
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Sunny, hot and humid Saturday with HI 100 or greater most areas south and west of KBLM along the I95 corridor. Its also Day 1 of an excessive heat warning. A heat advisory was issued for areas south and east of the warning. If the boundary/trough hangs up near the Mason Dixon line to ACY, then the potential would exist for late afternoon isolated severe thunderstorms Delmarva. Still plenty of instability there with better 0-6km bulk shear. There is a subtle indication in the convergent wind fields for a more sizable area of convection Delmarva and southern NJ late Sat. Fcst elements were produced using a 50 50 blend of 12z/22 GFS/NAM MOS guidance.
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&& .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... A cdfnt will be crossing the area Sat night and there cud be some lingering pops especially early. High pres will build back in on Sun. However both temps and humidity will be a bit lower on Sun, so while it will be hot, it will be a little more bearable. The heat returns with a vengeance on Monday, which at this point looks to be the hottest/most humid day. Heat index values will be in the 105-110 range in the urban corridor. Heat headlines are being modified as follows...for the urban corridor, an excessive heat warning will be issued through Monday, and it may need to be extended for Tuesday. We will likely fall short of criteria on Sunday, but it will still be hot. For Monday, the excessive heat watch will remain in place for the area surrounding the warning (that it was previously in effect for)...basically the entire cwa, outside of the Poconos and Sussex County NJ. Felt excessive heat warning was the best way to go with high impact events in Philadelphia this upcoming week. On Monday, low pres will be movg acrs ern Canada. Its assocd cdfnt will move thru the region and will touch off shwrs/tstms in a very hot and sticky ams. Tue and Wed look genly dry but the front will stall to the s and there cud be some low pops acrs the Delmarva extreme srn NJ. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR overall. Isolated showers or thunderstorms possible this evening mainly north of KPHL. There could be localized MVFR visibility due to fog/haze toward sunrise. Southwest winds 10-15 knots with some gusts to 20 knots, diminishing to less than 10 knots by late evening and becoming west to northwest overnight. Saturday...VFR overall. There is a chance for an afternoon shower or thunderstorm mainly in the vicinity of KILG, KACY and KMIV. Light west-northwest winds in the morning, turning westerly in the afternoon with gusts up to 20 knots. Winds may turn southwest at KMIV, KILG, and KACY during the afternoon. OUTLOOK... Saturday night-Sunday. VFR. High pressure. High confidence. Monday-Monday night...Generally VFR. A chance of shra/tsra which may briefly lead to MVFR/IFR. Gusty southwest winds 15-20 knots. Moderate to high confidence. Lower confidence of MVFR/IFR and precipitation coverage. Tuesday-Wednesday...VFR. High confidence.
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&& .MARINE...
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Through tonight...Southwesterly winds with gusts up to 25 knots especially nearshore of New Jersey, with seas expected to build up to 5 feet. The winds and seas should then subside before daybreak Saturday. Saturday...Sub small craft advisory conditions anticipated. Max gusts around 20 kt. OUTLOOK... Sat night-Sun...No marine headlines anticipated. Mon-Mon night...SCA conds psbl with increasing wind ahead of approaching cdfnt. Tue-Wed...No marine headlines anticipated. RIP CURRENTS...Added Cape May county to the moderate risk for the formation of dangerous rip currents this afternoon so that all of the NJ coast is now Moderate, while we`ve maintained low risk for the Delaware Beaches. Confidence on how much southerly component is a little below average so the moderate risk may end up low enhanced. Essentially... a 3-4 ft chop driven by gusty southwest wind of 15-20 mph is near parallel to shore. This will create a decent south to north long shore current and could result in some surprisingly strong rip currents by mid afternoon along the NJ shore, when also low tide occurs. Saturday: The probability for the formation of dangerous rip currents is Low. Looking further ahead, with the Atlantic Basin still devoid of tropical storms, the probable risk for the formation of dangerous rip currents should be low this weekend, especially with lighter winds and tendency more of an offshore component. Next Monday the 25th, we might have enough wave height to around 4 feet late in the day and water buildup due to southerly winds, to have a more widespread low enhanced or even moderate risk but confidence on seas building that high is below average. Water temperatures fell about 4 degrees between 6 am and 10 am, implying upwelling. Values were variably down into the mid 60s to lower 70s....colder along the NJ coast. Even colder upwelling may develop Saturday when the wind turns more westerly.
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&& .CLIMATE...
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Record high temperatures Saturday through Thursday. 23rd 24th 25th 26th 27th 28th PHL 101-2011 98-2011 96-1899 101-1892 101-1940 100-1941 ABE 99-1955 95-1999 95-1999 98-1940 98-1955 97-1949 ACY 105-2011 100-2011 99-2010 96-2011&1963 99-2005 98-1999 ILG 100-2011 98-2011 96-1987 99-1894 100-1894 101-1894 TTN 104-2011 98-1910 97-1999 99-1892 100-1894 101-1894 GED 104-2011 99-2011 99-2010 97-2012 98-2005 99-1949 RDG 100-2011 96-2010 96-1999 99-1940 98-1955 99-1941 MPO 91-1955 91-1914 90-1999 89-1949 91-1955 93-1949
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...Excessive Heat Watch from Monday morning through Monday afternoon for PAZ060>062-101-103-105. Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday for PAZ070-071-102-104-106. NJ...Excessive Heat Watch from Monday morning through Monday afternoon for NJZ007>010-012>014-016-020>027. Heat Advisory from 11 AM to 8 PM EDT Saturday for NJZ012>014- 016-020>027. Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday for NJZ015-017>019. DE...Excessive Heat Watch from Monday morning through Monday afternoon for DEZ002>004. Heat Advisory from 11 AM to 8 PM EDT Saturday for DEZ002>004. Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday for DEZ001. MD...Excessive Heat Watch from Monday morning through Monday afternoon for MDZ008-012-015-019-020. Heat Advisory from 11 AM to 8 PM EDT Saturday for MDZ008-012- 015-019-020. MARINE...Small Craft Advisory until 5 AM EDT Saturday for ANZ450>453. && $$ Synopsis...Nierenberg Near Term...Gorse Short Term...Drag Long Term...Nierenberg Aviation...Gorse/Nierenberg Marine...Drag/Nierenberg Climate...

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