745 FXUS61 KPHI 072246 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 646 PM EDT Sat Aug 7 2021 .SYNOPSIS... A stationary front will remain offshore, extending southward across the Southeast, with a wave of low pressure riding along the front through Sunday. A weak cold front will push southward across the northeast Sunday, but will stall just to our north and retreat northward as a warm front into early next week. Strong high pressure will build across the East Coast with a gradual warming trend through the week before a cold front pushes eastward towards the area Friday. && .NEAR TERM /THROUGH SUNDAY/... A mid level trough extended from the Great Lakes down to the southern Appalachians this evening. The axis of the trough will drift eastward and it should reach our region on Sunday afternoon. Surface low pressure was centered in southeastern Virginia early this evening. The low is forecast to move slowly to the northeast, passing near the mouth of Delaware Bay shortly after midnight. It is then expected to linger off the New Jersey coast from late tonight into Sunday. There will continue to be an area of moderate to heavy rain showers and isolated thunder associated with the system. It will remain relatively close to the center of the low. As a result, we anticipate that the precipitation will impact mainly eastern Maryland, Delaware and southern New Jersey tonight. Scattered showers are expected in the wake of the low on Sunday, mostly in New Jersey. Rainfall totals of 1.0 to 2.0 inches are possible across eastern Maryland, Delaware and southeastern New Jersey. The rainfall gradient to the northwest will be rather tight with Berks County, the Lehigh Valley and the Poconos receiving little, if any rainfall. Lows tonight are expected to favor the 60s. Highs on Sunday are forecast to range from the upper 70s to the middle 80s. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... The surface low will move far enough to the east Sunday night allowing for some subsidence and lack of rainfall. With ample surface moisture and light winds expected, a round of fog will develop overnight Sunday night but with at least some flow in the boundary layer it should not be widespread and dense. Diurnal heating on Monday with dew points near 70F will result in widely scattered afternoon and evening convection Monday especially west of the Delaware Valley. && .LONG TERM /TUESDAY THROUGH SATURDAY/... The forecast for next week remains on track with a building and broadening ridge across the eastern CONUS and a series of vort maxima pivoting through a larger scale trough across central Canada and the northern Great Lakes. By Tuesday, an upper level trough develops over the central CONUS and works with high pressure over the western Atlantic to continually pump warm and humid air over the east coast. As this happens, we should see daily chances for diurnally driven showers and thunderstorms with temps pushing into the lower 90s through at least Friday. Heat and humidity will gradually trend upward through Friday, with the greatest threat for heat indices between 100F and 105F Wednesday through Friday. The next chance for a cool down arrives Saturday as the upper level trough finally swings east over the Great Lakes bringing a cold front through the region likely featuring a round of showers and thunderstorms. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of today...Mainly VFR. MVFR CIGS possible at KILG, KMIV and KACY. SE to S winds 5 to 10 kts with a few gusts to 15 kts at times. High confidence. Tonight...VFR for KRDG and KABE. MVFR CIGs across the I-95 terminals. IFR likely for KMIV and KACY, especially after 05Z. Low confidence for I-95 terminals, higher confidence elsewhere. Forecast rides on how far precip shield pushes north and west. Winds turning easterly, then northeasterly around 5 kts. Patchy dense fog possible as well. Sunday...Sub-VFR restrictions in the morning from the I-95 terminals eastward, otherwise VFR. NW winds from 5 to 10 kts. Moderate confidence. Outlook... Monday through Thursday...Primarily VFR. MVFR possible Monday and Tuesday afternoons at KRDG and KABE due to showers and thunderstorms. MVFR possible Wednesday and Thursday afternoons across all the terminals. Winds primarily from a SE to SW direction at 10 knots or less. Moderate confidence. && .MARINE... Low pressure is forecast to move slowly northeastward over the coastal waters of Delaware and New Jersey from tonight into Sunday. The wind direction is expected to back from the south and southeast to the northeast and north tonight. It should be mostly from the north on Sunday. We are presently anticipating speeds to increase to 15 to 20 knots and wave heights on our ocean waters to build to 4 feet. However, with the low moving over warm waters it is possible that it will strengthen a bit more than we are forecasting. While a Small Craft Advisory is not currently in effect for Sunday, one may be needed for parts of our marine area. We will continue to monitor trends as they develop. Outlook... Sunday night through Thursday...Winds and seas are expected to remain below advisory thresholds. Rip Currents... There is a LOW risk for the development of dangerous rip currents this weekend. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Davis/Deal Near Term...Fitzsimmons/Iovino Short Term...Deal/Franklin Long Term...Deal/Franklin Aviation...Kruzdlo Marine...Davis/Deal/Iovino