Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 261340 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 940 AM EDT FRI AUG 26 2016 .SYNOPSIS... A weak cold front will move across the area today and push to our south tonight. High pressure builds to our north Saturday, then offshore later Sunday. An area of low pressure is expected to pass to our north Monday, bringing a front across the area later on Monday that will slowly sag southward through Tuesday. Another cold front is forecast to move across the area around Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Earlier showers have dissipated/moved out of the region. There is another area of light showers to our north, but expect this to stay north of our region through the day. So have removed mention of precip for the remainder of the day. Otherwise, few changes with the 930 AM update. An upper-level ridge still centered to our south will become the main weather feature today. This ridge is forecast to actually build a bit northward into our area by late afternoon. This will keep the stronger flow from the Midwest to the Great Lakes then to New England. At the surface, a weakening cold front will continue to settle south and eastward across our area through midday. This boundary may then end up dissipating during the afternoon as it is mostly just a dew point boundary. Given the building ridge, there is a very small window of opportunity for a shower or thunderstorm mainly through midday. There will be more of a cap across the southern areas due to the building ridge and then some drying occurs from northwest to southeast during the course of the day across much of the region. This coupled with a lack of defined forcing is not good for convective chances. Some convective cloud debris is expected to move across at least parts of the region this morning, however some increase in subsidence especially this afternoon along with some drying should allow for less cloud cover through the day across much of the area. It will be hot however for most areas as the boundary layer flow turns to the west and northwest for areas behind the weakening cold front. The heat indices will be driven by how much the dew points lower, however a humid day overall is expected with the highest heat indices anticipated from about the Philadelphia metro on south and east. It still appears that the heat indices fall short of advisory criteria. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... As the upper-level ridge continues to build across our region tonight, surface high pressure near the Great Lakes will slide eastward. This will allow for a more northeasterly low-level flow, although most places should have the winds decouple during the evening. While some high level clouds may drift across from time to time, overall a mostly clear sky is anticipated. It will be mild/warm, however the dew points should actually drop some allowing for a bit more radiational cooling. This is especially the case across the northern areas where dew points are forecast to be the lowest. && .LONG TERM /SATURDAY THROUGH THURSDAY/... The frontal boundary will continue to push to our south Saturday and stall or wash out south of the area over the weekend while high pressure builds to our north. This high will keep dry weather in place across the area through the weekend. Temperatures will remain warm over the weekend, but humidity levels will be much lower with dewpoints only in the 60s. The high pressure will build offshore of New England Sunday night into Monday, and a cold front will move into the area Monday. The front is expected to slowly move south of the area into Tuesday. Several vorticity impulses should move across the area Monday into Tuesday, which could help lead to isolated/scattered showers or thunderstorms. Another frontal boundary is forecast to move across the area Wednesday, then push south of the area into Thursday. There could continue to be some isolated/scattered showers or thunderstorms Wednesday or Thursday, but the chances remain small. Temperatures through next week will continue to be several degrees above normal, but not as warm and humid as today. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...VFR conditions are expected. Earlier low clouds have moved out of the region, and while there may be a few transient mid level decks through the day, expect VFR conditions to continue. A weak cold front settles across the area, therefore most terminals will have a wind shift to the northwest with an increase to around 10 knots. ACY should take the longest to have a wind shift to the west. A few showers will move across the region mainly early this morning. Tonight...VFR. Northwest winds diminish early, then become northeast or locally light and variable. OUTLOOK... Saturday through Sunday night...VFR conditions expected. Monday-Tuesday...Generally VFR expected. A chance of isolated showers or thunderstorms. && .MARINE... A weakening cold front arrives during the course of the day, however the wind shift to the northwest looks to hold off mostly until tonight. If a lingering pre-frontal trough however moves through, then a wind shift to westerly would occur sooner. The southwesterly flow has diminished some across much of the waters early this morning, and while some uptick may occur for a time we are expecting the conditions to remain below Small Craft Advisory criteria. Once the wind shift to the northwest occurs this evening, a turn more to the north and northeast is expected overnight as high pressure builds from the Great Lakes to New England. OUTLOOK... Saturday through Tuesday...Sub-Small Craft Advisory conditions expected to continue across the waters. RIP CURRENTS... For today...The risk for the formation of dangerous rip currents is low as the winds look light enough, and there should be a wind shift to more westerly by late day as a weak cold front settles through. For the weekend into early next week...With increasing long period swells (10-15 seconds), we will have an enhanced rip current risk. Monday and Tuesday could have the highest risk. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Robertson Near Term...Gorse/Johnson Short Term...Gorse Long Term...Robertson Aviation...Gorse/Johnson/Robertson Marine...Gorse/Robertson is the U.S. government's official web portal to all federal, state and local government web resources and services.