035 FXUS61 KPHI 110201 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1001 PM EDT Thu Apr 10 2025 .SYNOPSIS... A low pressure system will track toward the Mid-Atlantic region tonight. This system will move into the forecast area on Friday and then linger through Saturday. This will result in below normal temperatures as well as some wet weather. The system will move east over the Atlantic on Sunday. This will allow high pressure to move into the region. The high should remain in place through most of Monday providing us with moderating temperatures. A cold front will move through the region later on Tuesday. The will result in below normal temperatures on Wednesday. The region could see a slight warmup on Thursday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of late this evening, an initial surface low pressure center continues to weaken over western Pennsylvania while in the upper levels a trough deepens over the eastern U.S. Observations continue to indicate light precipitation reaching the ground, now scattered across much of the region. The more concentrated showers remain just to the west of the region though they have become a bit more diminished as they have progressed eastward. However, heading into the overnight, more widespread rain/showers are expected to form as forcing strengthens with the upper trough deepening and more moisture moving in. At the surface, low pressure will start to reorganize farther south near North Carolina but there will still be a trough extending north from this associated with the decaying northern low. PoPs increase to around 60-80% across the area after midnight, though precipitation will remain on the lighter side. With the loss of daytime heating, temperature profiles in the Poconos support some wet snow falling overnight, with accumulations up to an inch possible. Rainfall amounts will range from a tenth to a quarter of an inch overnight. Lows fall into the upper 30s/low to mid 40s with temperatures near/below freezing within the Pocono Plateau. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... Coastal low pressure will affect the region through the short term, though maximum impact looks likely to occur through Friday night. System develops over the Carolinas on Friday, with rain slowly but surely heading northeastward toward us. During the day, the rain looks likely to remain fairly light and more intermittent, especially the farther north and east one gets. With the clouds, occasional rain and easterly winds, temps will struggle to rise. In fact the majority of the area will see highs only in the 40s with highs in the low 50s confined mainly to parts of far southern NJ and Delmarva. So all in all, a cool, raw day. By late day we will have northeast winds gusting up to 30 mph along the coast and up to 25 mph inland. Most guidance focuses the bulk of the rain and strongest winds over the region Friday night as the low pressure system heads northeast off the Virginia/Carolina coast. Rain may be heavy at times, and there might be enough elevated instability for a thunderstorm across southern parts of the forecast area. Winds will be gusty from the northeast, with gusts reaching 25 to 35 mph. Overnight lows will range from the low to mid 40s north to the low to mid 30s north, especially over the higher elevations. For this reason, a mix with or change back to wet snow is likely over the Pocono Plateau with the potential for another inch or so in places. Otherwise, rain amounts falling during the evening and overnight period should amount to a half inch to inch over the 12 hour period so not enough to cause any widespread flooding issues but there will be rises on rivers and streams and there could be some urban and poor drainage type flooding. The low starts heading farther off the coast during the day Saturday and Saturday night, but the upper trough nearby and continuing northeasterly flow likely keeps a few showers around at least on Saturday, probably abating Saturday night. Saturday will also remain breezy and chilly under mostly cloudy skies. Expect storm total rainfall for the period running from tonight through Saturday night generally 1 to 1.5 inches with locally higher amounts of 1.75 to 2.00 inches possible. Again, the heaviest will fall late Friday through Friday night but rises on rivers will continue into the weekend. By Sunday, the system should finally pull far enough away to the north and east to bring mainly dry conditions with even some partial sunshine possible by afternoon...especially over eastern PA. Temperatures will also rebound with highs getting back up into the middle to upper 50s for most. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... The weekend low pressure system will continue to slide east Sunday night. A weak mid-level ridge will take its place. Overnight lows will be in the mid 30s to lower 40s. Monday may be the nicest day of the long term with high pressure in place and westerly downsloping winds. Highs will be in the 60s for most of us, possibly touching 70 across the Delmarva. A series of cold fronts will cross the region Tuesday into Wednesday. At the moment, we have the first front moving through Tuesday morning and the second one sometime during the day on Wednesday. It doesn`t appear there will be a significant change in airmass behind the first cold front, so high temperatures on Tuesday will still be in the 60s for most of us. We`ll hold the far northwest zones in the 50s. I have chance PoPs painted in the grids. Cooler air will push into the region behind the second cold front on Wednesday. Highs will get knocked down into the 50s for most, with some 40s in the Poconos. For Wednesday night, we may have frost/freeze concerns with lows possibly dipping into the 30s. And by this point, the majority of the forecast area, sans LV/Poconos/NW NJ, will be frost/freeze active. No precipitation is expected on Wednesday. Thursday looks to be precipitation free as well with moderating temperatures (but only slightly) spurred on by some mid-level zonal flow. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...MVFR ceilings will develop at KRDG and KABE by around 03Z. The I-95 terminals will follow between 03Z-07Z. KMIV and KACY may hold on to VFR ceilings for a bit longer, but still MVFR by around 06Z. Ceilings should lower to IFR between 08Z-10Z for all terminals. Rain showers move in, though any vsby restrictions should be fairly minimal through most of the night. Southeast wind around 10 kt shifting to east-northeast overnight. High confidence in the overall pattern, moderate confidence in timing. Friday...IFR ceilings will likely be in place areawide to start the day, and should remain through 00Z. Widespread rainfall will also cause vsby restrictions at times (2-3 SM in the heaviest rain), though vsby restrictions will likely be isolated and fairly brief compared to the prolonged and widespread ceilings of less than 1 kft. East-northeast wind around 10 kt. A few gusts around 15-20 kts can`t be ruled out in the afternoon and evening. Moderate confidence. Outlook... Friday Night...IFR through most of the night in low clouds and rain. Saturday...IFR/MVFR in rain and low clouds to start the day. Some improvement is possible late. Saturday Night...sub-VFR at times as some rain showers and low clouds linger. Sunday through Tuesday...Mainly VFR. A few passing showers and increased cloud cover possible Monday night into Tuesday. && .MARINE... Winds and seas will start to ramp up through tonight with seas around 4 feet by morning and east winds 15 to 20 knots gusting up to 25 knots by morning. A Small Craft Advisory goes into effect at 6 AM Friday for our ocean zones and 9 AM Friday for the Delaware Bay. These conditions continue through the day Friday. Outlook... The strongest winds associated with a coastal low look to be Friday night into Saturday with Gale conditions possible over our ocean zones where a Gale Watch is now in effect 6 PM Friday to 6 PM Saturday. Small Craft Advisory conditions persist on the Delaware Bay. Seas building upwards of 6 to 9 feet. Winds abate Saturday night but seas could stay at or above Small Craft Advisory levels through at least a portion of Sunday. Sunday night...Seas will continue to diminish Sunday night. There still could be some residual SCA conditions in play during the evening hours. Sub-SCA conditions are expected overnight. Monday and Monday night...Sub-SCA conditions are expected Monday and most of Monday night. We could see seas tick up a notch to 5 feet toward dawn on Tuesday. Tuesday...Like late Monday night, SCA conditions are possible. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 9 AM Friday to 6 PM EDT Saturday for ANZ430-431. Small Craft Advisory from 6 AM to 6 PM EDT Friday for ANZ450>455. Gale Watch from Friday evening through Saturday afternoon for ANZ450>455. && $$ SYNOPSIS...Kruzdlo NEAR TERM...AKL/Fitzsimmons/Hoeflich SHORT TERM...Fitzsimmons/RCM LONG TERM...Kruzdlo AVIATION...Cooper/Guzzo MARINE...Fitzsimmons/Kruzdlo