Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 020103 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 903 PM EDT FRI JUL 1 2016 .SYNOPSIS...
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A cold front will move through the area late this evening and offshore late tonight. The front will stall to our south this weekend while high pressure builds into our region. The front will start to lift back northward with several waves of low pressure tracking along it Monday and Tuesday. High pressure briefly returns Wednesday before shifting off the coast late in the week.
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&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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900 PM Update: Cancelled the remainder of the Severe Thunderstorm Watch. Some convection expected to continue for awhile longer with lingering instability, however the intensity continues to diminish overall and areal coverage has decreased. Overnight...After lingering convection dissipates or advances off the coast, models have been consistent with clearing conditions quickly behind the cold front which should be offshore by 09z. Depending how quickly the clouds clear and if the winds decouple, patchy dense fog may form. The fog should be limited however as drying arrives from the west through the overnight hours.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... Sunny start with some afternoon cirrus. A beautiful day with a northwest wind of 15-20 mph. PWAT down to .65 inches. Fcst element basis was a 50 50 blend of the 12z/1 gfs/nam mos. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... A vertically-stacked low will drift northeastward across eastern Canada while the cold front that moves through our area tonight stalls to our south through the remainder of the weekend. In between these two systems, weak high pressure will be positioned over the Midwest and northern mid-Atlantic regions. We are expecting a dry stretch of weather Saturday night and Sunday with temperatures near normal. The next system we are watching is a shortwave trough currently over the Four Corners region. This disturbance is forecast to get steered by the stronger westerlies aloft residing south of the broad longwave trough. It is forecast to move eastward along a stationary front that resides across the eastern two-thirds CONUS this weekend and early next week. Some of the earlier model guidance had this disturbance tracking far enough to our south to keep us dry for Monday and Tuesday. The latest model runs today have trended slightly farther north with the disturbance and frontal boundary. Accordingly, a dry Independence Day is looking less likely as even a slight northward shift could bring the threat of showers and storms to our area. There is also a possibility that a more organized MCS moves through our area (especially for the southern half of the CWA), which could potentially impact outdoor holiday plans,including fireworks. Highest PoPs on Monday reside across the Delmarva and southern NJ during the afternoon and evening, when diurnal instability peaks. PoPs are still highest across our southern zones Tuesday but decrease late in the day with the front eventually moving back to our south and subsidence building overhead in wake of this shortwave trough. Timing of precip will need to be refined as we get closer to the event and details on the mesoscale becoming clearer. There is also a potential for heavy rainfall and flooding in vicinity of where the frontal boundary sets up. PWATS could exceed 2" near the front. The latest WPC QPF shows a max of2.5 inches in the Delmarva. A dry weather pattern returns Tuesday night and Wednesday with high pressure briefly in control. South to southwesterly return flow looks to develop either Wednesday night or Thursday once the high moves offshore. The heat then builds across the area as the upper ridge shifts to the Southeast states and possibly builds northward. We could see our first 90 degree day in Philadelphia for the first time since June 20th as early as Wednesday but more likely by Thursday (low 90s are favored farther inland toward ABE/RDG Wednesday and Thursday). We will likely need to mention in the upcoming days the potential for heat hazards late next week (heat indices near 100F are forecast for Friday). There is also a chance for showers and storms Thursday and Friday with the latest guidance showing our area positioned just downstream of the convective ring of fire. In this region, several fast-moving MCCs may track around the northern periphery of the upper ridge where a belt of stronger westerlies reside. && .AVIATION /01Z 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 with isolated to scattered showers/thunderstorms ending/moving off the coast by about 05z. Patchy MVFR/IFR stratus/fog can develop, however this should be limited as drier air works in overnight. Light south to southwest winds shift to northwest. Saturday...VFR. Northwest wind gusts 15-20 kt. Outlook... Saturday night through Sunday night...Predominately VFR conditions expected. W to NW winds 5 to 10 kt Saturday night, becoming W to SW Sunday. Monday and Tuesday...MVFR to IFR possible with multiple rounds of showers and storms possible. Better chances from PHL southward. Tuesday night and Wednesday...Mainly VFR.
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&& .MARINE...
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Otherwise winds and seas should generally remain below SCA criteria through Saturday. An ese swell of 2.5 ft may be surpassed by a southerly swell of 3 feet tonight, then tomorrow we drop back to the seasonally persistent and normal se swell of 2.5 feet. Saturday is a nice day to be out on the water although with some leftover southerly swell. Outlook... Saturday night through Wednesday...Winds and seas (3 ft or less thru Tuesday, 3-4 ft Wednesday in our coastal Atlantic zones) are expected to remain below SCA criteria. However, locally stronger wind gusts possible in thunderstorms Monday and Tuesday. Greatest risk to see storms will across our southern zones.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Klein Near Term...Drag/Gorse Short Term...Drag/Johnson Long Term...Klein Aviation...Drag/Johnson/Klein Marine...Drag/Johnson/Klein

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