869 FXUS61 KPHI 170731 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 331 AM EDT Thu Apr 17 2025 .SYNOPSIS... High pressure builds in for our Thursday before shifting offshore of the Mid Atlantic coast Thursday night into Friday as a warm front lifts north of the area. Return flow sets up across the east coast, before a cold front moves across the area later Saturday then stalls to our south. This front will move back northward as an occluded frontal system moves across the area early next week. High pressure returns for the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... An upper trough over the Northeast with strong shortwave energy will move east and offshore as the morning progresses. Mid-level ridging builds in from the west throughout the day. Meanwhile, surface high pressure centered over the Great Lakes and Ohio Valley will build to the south and east and will be centered over the Mid-Atlantic by this afternoon. The high then slides offshore tonight and will be centered off the Mid-Atlantic coast. Stratocu deck over the northern half of the forecast area early this morning will gradually thin out and dissipate as the trough and shortwave move offshore. Mostly sunny skies then on tap for today. Any patchy frost will melt off shortly after sunrise as temperatures warm into the 40s. Temperatures will rebound back closer to normal levels with highs in the upper 50s to low 60s. Not as windy today compared to Wednesday, but there will still be gusts to at least 20 mph this afternoon, with slightly higher gusts in the higher elevations of the southern Poconos and northern New Jersey. Winds begin to diminish around dinnertime. Clear skies with light southerly winds on tap for tonight. Warm air advection will be underway, and lows will be in the upper 30s to low 40s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... High pressure remains in control for Friday which leads to a dry day with high temperatures in the low 60s to low 70s. Winds will be increasing throughout the day out of the south. This helps usher in warmer air, but we also at times could see gusts upwards of 25-30 mph. Our winds stay out of the southwest Friday night which leads to our lows being in the 50s and gusts at times will be around 20 mph. As the high pressure system exits Friday night, a warm front lifts northward. There does not look to be too much moisture with this warm front and mainly adds some more cloud cover into Saturday. On Saturday, we are well into the warm sector with temperatures reaching the low 80s for most with the Poconos being in the mid 70s. A cold front will approach the area from the west which will lead to the chance for some showers Saturday afternoon into Saturday night with a slight chance for a thunderstorm. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... The cold front pushes south of the area on Sunday. Winds turn to be out of the northwest behind the front but it does still stay on the milder side on Sunday with highs in the 70s for most. A brief area of high pressure builds in from the north on Sunday which keeps the area dry. This high pressure system is brief as it moves out for Monday. By Monday, our next system approaches as a warm front once again moves northward during the day. Highs on Monday will be in the 60s for most. A cold front moves in from the west late Monday into Monday night bringing some rain showers to the area. An isolated thunderstorm cannot be ruled out. Once the cold front departs, high pressure moves in for Tuesday and Wednesday which keeps things quiet. Temperatures also once again turn milder towards midweek. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...VFR/SKC. W-NW winds 5 to 10 kt, increasing to 10 to 15 kt with 20 to 25 kt gusts late this morning. Winds diminish to 5 to 10 kt after 21Z. High confidence. Tonight...VFR/SKC. W-SW winds 5 to 10 kt, becoming S 5 kt or less. High confidence. Outlook... Friday...VFR conditions expected. A south wind gusting to 20-25 knots. Saturday...Sub-VFR conditions possible with some showers moving through during the afternoon into Saturday night. Sunday...VFR conditions expected. Monday...Sub-VFR conditions possible with some showers moving through during the afternoon into Monday night. && .MARINE... Sub-Small Craft Advisory conditions on tap for today and tonight. West to northwest winds 10 to 15 kt with gusts up to 20 kt, becoming SW 5 to 10 kt late this afternoon and tonight. Seas 2 to 3 ft. Outlook... Friday...Small Craft Advisory conditions develop Friday evening and continue into Friday night. Saturday...Small Craft Advisory conditions continue for much of the day Saturday. Sunday...The conditions are anticipated to be below Small Craft Advisory criteria Monday...The conditions are anticipated to be below Small Craft Advisory criteria && .FIRE WEATHER... A much drier airmass will be over the area today compared to Wednesday, but winds will be much lighter. Min RH values will range from 20 to 25 percent with west to northwest winds 10 to 15 mph with 20 to 25 mph gusts. Will reach out to state fire weather partners to determine of fine fuels dried out enough to warrant a Special Weather Statement for the risk for rapid fire spread this afternoon. Recent rainfall and the greenup that is occurring are limiting factors for this threat. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Frost Advisory until 9 AM EDT this morning for PAZ060-070-071- 101>104-106. NJ...Frost Advisory until 9 AM EDT this morning for NJZ012-013- 015>022-027. DE...Frost Advisory until 9 AM EDT this morning for DEZ001. MD...None. MARINE...None. && $$ SYNOPSIS...Guzzo/Robertson NEAR TERM...MPS SHORT TERM...Guzzo LONG TERM...Guzzo AVIATION...Guzzo/MPS MARINE...Guzzo/MPS FIRE WEATHER...