FXUS61 KPHI 190554 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 154 AM EDT Sun Apr 19 2026 .WHAT HAS CHANGED... Freeze Watch issued for much of our NJ and PA zones for Monday night. && .KEY MESSAGES... 1. A strong cold front will bring rain showers to the area tonight into Sunday. 2. Widespread minor tidal flooding along the Atlantic coasts of New Jersey and Delaware, Delaware Bay, and the tidal Delaware River with tonight's high tide. 3. Much colder air early next week with frost/freeze conditions, followed by a return to above average temperatures later in the week. && .DISCUSSION... KEY MESSAGE 1...A strong cold front will bring rain showers to the area tonight into Sunday. A cold front will move into the area late tonight and should move off the coast by mid day Sunday. This front, combined with the surface low sliding along the front, will provide enough lift for widespread rain across the area. Chances for measurable rain range from 70 to 90 percent. That being said, this is unlikely to result in substantial rain amounts. Storm (shower) motions should be relatively fast, and the front itself has trended faster. Thus, rain amounts are forecast to be a few hundredths of an inch up to one half an inch. In terms of other hazards, instability, especially surface or low level based instability is forecast to be very limited (less than 50 J/kg of CAPE). Thus the risk for other thunderstorm hazards is very low. That being said, there is some very elevated instability (for parcels above 850 mb), especially west of the fall line, so can't rule out a rumble of thunder or gusty winds. Though this is a strong cold front, the temperature difference won't feel as dramatic as it could, thanks to a marine layer staying mostly in place over our region today. None the less, for most inland areas, temperatures on Sunday will be 5 to 20 degrees colder as compared to Saturday. KEY MESSAGE 2...Widespread minor tidal flooding along the Atlantic coasts of New Jersey and Delaware, Delaware Bay, and the tidal Delaware River with tonight's high tide. A Coastal Flood Advisory remains in effect for the Atlantic coasts of New Jersey and Delaware, as well as along Delaware Bay and up the tidal Delaware River for the high tide cycles tonight. High astronomical tides associated with the New Moon that occurred yesterday and onshore flow today and tonight is forecast to result in widespread minor tidal flooding with tonight's high tide along the Atlantic coasts of New Jersey and Delaware, Delaware Bay, and the tidal Delaware River. A northeast to east wind will become southeasterly by later today into this evening, with surge values increasing to near 1 foot above normal. This will put most tidal areas into minor flood stage during high tide tonight. A modest offshore wind will develop in the wake of a cold front on Sunday, which should limit the risk of any additional flooding for Sunday night's high tide. No tidal flooding is forecast for our portion of the Eastern Shore of Chesapeake Bay. KEY MESSAGE 3...Much colder air early next week with frost/freeze conditions, followed by a return to above average temperatures later in the week. A cold mid-level trough, surface high pressure, clear skies, and light winds all look likely Monday night. As a result, we are expecting efficient radiational cooling conditions and a widespread freeze event early Tuesday morning. Frost early Tuesday morning might be somewhat limited given a much drier low-level air mass is expected to be in place. But outside of the larger cities and away from the immediate coast, temperatures are expected to drop below freezing. In some cases, well below freezing. All of our counties now have an active growing season due to the recent excessive warmth. Blooms/vegetation have quickly initiated and in some cases are ahead of schedule. With this mind, a Freeze Watch has been issued for Monday night/early Tuesday morning. High temperatures both Monday and Tuesday are forecast to be in the 40s and 50s across the region, which is several degrees below average. A return, southerly, flow will become established Tuesday and continue into Wednesday. This along with an increase in warm air advection and rising heights will result in temperatures climbing back above average Wednesday through Friday. A warm front may arrive at the end of the week. As of now, rainfall Monday through Friday of next week looks to be on the lighter side, maybe a 0.10 to 0.50 for the week. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through 18Z...Expect prolonged MVFR and IFR conditions to continue. The main controlling factor is ceilings, but there have been, and will continue to be some visibility restrictions in BR and FG, especially at KACY. Winds currently are less than 10kt favoring an Easterly direction. At KMIV and KACY, low level wind shear is possible for the next few hours as a low level SSW jet is overhead. Ceilings and visibility are expected to improve, and winds will abruptly shift to northwesterly between 10 and 15Z as a cold front moves through. Winds gusting up to 30kt are possible behind the front. After 18Z...Lower clouds and rain showers will slide east off the coast, resulting in a return of VFR conditions from west to east. Winds will remain out of the northwest, but begin to slowly diminish after 21Z. Tonight...VFR conditions expected. Westerly winds near or below 10kt. Outlook... Monday through Tuesday...VFR. West-northwest wind gusts to around 20 knots Monday, quickly diminishing Monday night. Wednesday...Some MVFR conditions are possible at times due to showers. Thursday...VFR conditions expected. && .MARINE... Winds will shift to northwesterly and increase quickly behind a cold front later this morning. Guidance has trended windier near the mouth of the Delaware Bay and downstream, which is not uncommon in these flow regimes due to funneling effects along the bay. Therefore, have issued a gale warning for the lower Delaware Bay, the near coastal areas (out to 20 nmi) from Great Egg Inlet NJ to Fenwick Island DE, and the farther marine areas (20 to 60 nmi) from Cape May NJ to Fenwick Island DE. For the rest of the marine areas, winds are expected to stay between 25 and 30 kt during the day time, so a Small craft advisory remains in effect for the rest of the Delaware Bay and near coastal areas (SCAs are not issued for the 20 to 60 nmi marine areas). Once winds diminish by early this evening, winds and seas are expected to remain below SCA criteria through the rest of tonight. Outlook... Monday through Thursday...Sub-SCA conditions expected. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Freeze Watch from late Monday night through Tuesday morning for PAZ054-055-060>062-070-071-101>106. Coastal Flood Advisory until 6 AM EDT early this morning for PAZ070-071-106. Freeze Warning from 11 PM this evening to 10 AM EDT Monday for PAZ054-055. NJ...Coastal Flood Advisory until 3 AM EDT early this morning for NJZ016. Freeze Watch from late Monday night through Tuesday morning for NJZ001-007>010-012-013-015>023-027. Coastal Flood Advisory until 2 AM EDT early this morning for NJZ012>014-020>027. Coastal Flood Advisory until 6 AM EDT early this morning for NJZ017>019. DE...Coastal Flood Advisory until 3 AM EDT early this morning for DEZ001. Freeze Watch from late Monday night through Tuesday morning for DEZ001>003. Coastal Flood Advisory until 2 AM EDT early this morning for DEZ002>004. MD...Freeze Watch from late Monday night through Tuesday morning for MDZ012-015-019-020. MARINE...Small Craft Advisory from 8 AM this morning to 6 PM EDT this evening for ANZ430-450>452. Dense Fog Advisory until 6 AM EDT early this morning for ANZ431-451>455-481>483-485. Gale Warning from 8 AM this morning to 5 PM EDT this afternoon for ANZ431-453>455-485. && $$ DISCUSSION...Franklin/Gorse/Kruzdlo/Johnson AVIATION...Gorse/Kruzdlo/Johnson MARINE...Gorse/Kruzdlo/Johnson