


Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
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513 FXUS61 KPHI 161830 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 230 PM EDT Sat Aug 16 2025 .SYNOPSIS... High pressure centered near the Canadian Maritimes will move offshore Saturday night into Sunday. A cold front passes through the region Sunday night then becomes stationary over the Mid- Atlantic into the new week. High pressure builds in from the north through the middle to end of next week as Hurricane Erin passes by well offshore. && .NEAR TERM /THROUGH SUNDAY/... A surface trough to our west is providing a focus for isolated showers and storms to develop this afternoon. It is possible that a few showers and storms could work their way into our region. We have even seen isolated showers develop in the Pine Barrens, likely along a differential heating boundary where we saw clouds clearing earlier today. Some of the storms to our west have been very slow moving and efficient rain producers, so will keep a close eye on radar trends through the afternoon. Expect this activity to diminish quickly with sunset. Overnight, there is a small chance (less than 20%) for fog to develop. However, complicating this potential is the fact that mid level clouds may advect into the region as the high shifts further east which would limit fog development. For now have left a mention out of the forecast given the low probability of occurrence. On Sunday, the surface high will continue to shift east and a cold front is expected to trail closely behind. At this point, it appears as if the front won`t arrive during the day, rather Sunday night. However, this will still have two consequences for the weather during the day tomorrow. First, tomorrow is expected to be a few degrees warmer than what we saw on Saturday. Second, another round of showers and storms is possible as a weak pre- frontal trough over our region in the afternoon could serve as a focus for convective development. At this point, the main concern with any storms tomorrow will be heavy rain. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As the cold front passes through Sunday evening, we can expect a few scattered showers and thunderstorms. Overall baroclinic forcing looks weak with unimpressive lapse rates, thus coverage at this point still looks limited. POPs remain in the 20-35% range with limited severe and flash flooding potential. High pressure builds in behind the Sunday night, pushing any showers or storms out to sea and allowing drier air to filter in. Overnight lows will be in the 60s to around 70. High pressure building in from the north and east will lead to persistent onshore flow Monday and Tuesday. As a result, a cooler airmass will be in place allowing high temps Monday afternoon to only reach the mid 70s to low 80s with similar temperatures expected Tuesday. With the frontal boundary lingering just south of the area, this will keep the chances for some light showers around for both Monday and Tuesday but POPs are only around 20 to 30 percent. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A frontal boundary will continue to linger nearby Tuesday night through Wednesday and as some shortwave energy moves in from the west, this will bring an increasing chance for some showers and possibly a few embedded thunderstorms. Temperatures will remain on the cool side of climo. The other main story will be Hurricane Erin which is currently located east of the northern Leeward Islands. It is expected to track well offshore to the east of the area later Wednesday into Wednesday night but we`ll still likely have some indirect impacts from it. Potential impacts include a high risk for rip currents, rough surf, and the potential for minor coastal flooding beginning as early as Monday and lasting into Thursday. Please refer to the National Hurricane Center for more details and stay tuned to the local forecast. High pressure should bring fair and dry weather for the end of the week. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through Tonight...Prevailing VFR conditions expected. There is a small chance (20% or less) for another round of low clouds and/or fog. However, few models depict this, and any mid level clouds overnight could limit fog or low stratus development. Thus, for now, have not included this potential in the TAFs. IF it were to happen, the period of highest risk would be between 09 and 12Z. Winds generally out of the SE or SW. Sunday...Prevailing VFR. There is a 20 - 30% chance of afternoon storms for KABE and KRDG, which could result in temporary MVFR conditions. However, coverage is expected to be very limited, so low confidence if the terminals would be directly impacted. Winds mostly light (less than 10 kt) out of the southwest, but an afternoon sea breeze could get as far inland as KACY and KMIV shifting winds to SSE. Outlook... Sunday night through Monday...A period of MVFR cigs may develop due to low stratus. Tuesday through Wednesday...Mainly VFR with periods of sub-VFR conditions possible from showers and thunderstorms. && .MARINE... Winds and seas will stay below Small Craft Advisory conditions through Sunday. Outlook... Monday...SCA conditions with the passage of a frontal boundary. Winds turn northeast with gusts around 20-25 kts with seas building to 5-7 feet. Tuesday through Thursday...SCA conditions continue due to the approach of what is currently Hurricane Erin. Elevated winds and seas develop Tuesday and will last into at least Thursday. Seas 5-7 feet Tuesday build as high as 8-12 feet by Thursday. Rip currents... Buoy observations indicate an underlying long period (15 sec) swell that is not being modeled well. This, combined with a light onshore flow, would suggest a MODERATE risk for the formation of dangerous rip currents, even though the waves are only 1 to 2 feet. For Sunday, southerly winds around 10-15 mph, breaking wave heights around 1-2 feet, and a light easterly swell around 4-5 seconds. As a result, have opted to continue with a LOW risk for rip currents for all beaches on Sunday. However, will need to continue to monitor trends with the long period swell that was observed Saturday morning. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...Fitzsimmons/Franklin/MJL NEAR TERM...Johnson SHORT TERM...Fitzsimmons/MJL LONG TERM...Fitzsimmons/MJL AVIATION...Johnson/MJL MARINE...Johnson/MJL