633 FXUS61 KPHI 121023 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 623 AM EDT Thu Jun 12 2025 .SYNOPSIS... Bermuda high will remain in place offshore, with weaker high pressure over the Mid- Atlantic sliding offshore by Friday. A weak cold front approaches from the northwest tonight and becomes nearly stationary over the Mid- Atlantic into the weekend. Several waves of low pressure will affect the area starting late Friday and continuing into the new week, with multiple rounds of showers and storms, and below normal temperatures likely. && .NEAR TERM /THROUGH TONIGHT/... Some areas of fog have developed across southern Delaware and adjacent areas of Maryland. This bank of fog could spread north and impact coastal Cape May County as well before mixing out later this morning. Otherwise, the forecast remains on track. It appears that today will be the warmest of the stretch, with most urban areas expected to reach the low 90s while mid/upper 80s will be found in other areas. For many areas, this could be the first 90 degree day of the year. Dewpoints will trend upward too, so hot and muggy today. We do expect a few scattered tstms to develop across the North/Northwest areas and track into Northern NJ. We`ll continue with the slight chance to low chance pops that we had earlier. The SPC has indicated that a Marginal risk for severe thunderstorms exists across these areas today. Large hail and damaging wind threats are low but not zero. Tonight, any tstms/showers end during the evening then muggy and mild overnight. Lows will only dropping to the mid/upper 60s for S/E areas and upper 50s to low 60s N/W. A weak cold front will slip southward across the area tonight. Clouds early then decreasing sky cover late. Patchy fog where any rains fall. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... Weak high pressure across the region Friday morning moves offshore Friday afternoon. A stationary front will be draped over the Mid- Atlantic area, and low pressure slowly approaches from the west late Friday on that boundary. The low passes through Delmarva and southern New Jersey Saturday morning through Saturday afternoon before departing. A few showers and perhaps a thunderstorm may develop late Friday afternoon as some shortwave energy approaches from the west but the bulk of the activity hold off until Friday night through Saturday morning with the passage of the low. Highest instability will be focused on Delmarva, generally in the vicinity of the low, but not expecting severe weather. Will carry slight chance to chance for thunderstorms, mainly Friday night. After the low departs late Saturday morning, the stationary front over the Mid-Atlantic lifts north as a warm front as low pressure moves into the Great Lakes. Some shortwave energy ahead of that low moves into the northern half of the forecast area. With surface dew points rising through the 60s and approaching 70, another round of showers and thunderstorms is possible late in the day. PoPs will mostly be chance, but PoPs will be likely for portions of the southern Poconos and western Lehigh Valley. The threat for severe weather is minimal, but with increasing dew points and PWATs over 1.5 inches for most of the area, and over 2 inches for Delmarva, locally heavy rain is a threat. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Low pressure approaches from the west and slowly works its way through the Mid-Atlantic and Delmarva Sunday through Monday. A prolonged period of unsettled weather is on tap during this time with showers and isolated to scattered thunderstorms. Given abundant low level moisture with surface dew points well in the 60s, locally heavy rain will develop from time to time. WPC has a Marginal Risk (1 out of 4) for excessive rain Saturday night through Sunday and again Sunday through Sunday night. Rain tapers off on Monday as low pressure departs. With a prolonged period of onshore flow, temperatures will be on the cool side through the weekend and into Monday with highs on Sunday in the low to mid 70s and highs on Monday in the upper 60s to low 70s. Several additional shortwaves approach from the west as the week progresses, and weak waves of low pressure will develop as a result. This will keep low chance PoPs in the forecast through Wednesday. Temperatures will rebound somewhat on Tuesday before warming back into the 80s on Wednesday. After multiple cloudy days, a return of sunshine should be anticipated on Wednesday as well. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...VFR with high clouds expected. Light winds becoming West around 10 knots after 13Z. A few showers/tstms possible for the late afternoon across NE PA or North NJ. Kept the VCSH in the KABE TAF for this. High confid. Tonight...VFR expected. Winds mostly light and variable, but turning North or Northeast for most sites after 02Z/03Z. High confid overall. Outlook... Friday...VFR initially, then scattered afternoon SHRA develop with brief sub-VFR conds possible, mainly west of the I-95 terminals. Friday night through Saturday...Prevailing MVFR to IFR likely, mainly from low ceilings. SHRA and scattered TSRA. A break in SHRA possible around midday Saturday before ramping up again Saturday afternoon. Saturday night through Monday...Prevailing MVFR to IFR likely, mainly from low ceilings. SHRA and scattered TSRA. && .MARINE... An area of dense fog has developed and spread north along coastal Delaware and offshore of southern New Jersey. Visibility could be reduced to 1 NM or less at times in this area, which may continue spreading northward some before visibility improves later today. A Dense Fog Advisory was issued to highlight this threat through noon. Otherwise, high pressure offshore and a cold front approaching from the North/Northwest later today and tonight. Winds will remain below SCA levels as winds come in from the West/Southwest today and early tonight. After that, winds across the northern waters will turn North/Northeast into the evening and this wins shift will trend southward thru the night. Fair weather overall, but a stray shower across the far northern waters possible this evening. Low confid regarding shower activity. Outlook... Friday through Monday...Overall, sub-SCA conditions expected, though there is the potential for SCA conditions Sunday night through Monday. VSBY restrictions in showers, drizzle, and isolated to scattered thunderstorms throughout this period. Areas of fog also possible. Rip Currents... For today, southwest winds around 5-10 mph turning south in the afternoon behind a sea breeze. Breaking wave heights of 1-3 feet with a weak southeasterly swell of 1 foot around 9 seconds. We will be about 36 hours removed from the Full Moon from early Wednesday morning, therefore expecting to see less of an impact to tides as a result. We have a LOW risk for dangerous rip currents at all beaches. For Friday, east-northeast winds around 5-10 mph turn more easterly in the afternoon. Breaking wave heights remain around 1-3 feet with a weak southeasterly swell of 1 foot around 9 seconds. No major differences from Thursday, so we will maintain a LOW risk for dangerous rip currents at all beaches. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Dense Fog Advisory until noon EDT today for ANZ431-453>455. && $$ SYNOPSIS...MPS/Staarmann NEAR TERM...OHara/Staarmann SHORT TERM...MPS/Staarmann LONG TERM...MPS/Staarmann AVIATION...MPS/OHara/Staarmann MARINE...MPS/OHara/Staarmann