Shawnee Mountain Snow Report

320 FXUS61 KPHI 210829 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 429 AM EDT Mon Sep 21 2026 .WHAT HAS CHANGED... Increasing confidence of gale conditions during the second half of the week. Models are in slightly better agreement on the track of the late week coastal low, though there remains uncertainty in its evolution from Friday onward. There is increasing confidence in the details of the coastal flood and rip current risks through the first half of the week. && .KEY MESSAGES... 1. A frontal boundary south of the region will keep rain chances around through mid-week, especially across southern portions of the area. 2. A closed mid-level low ejecting from the Ohio Valley is expected to lead to the development of a surface low off the Eastern Seaboard during the middle and latter parts of this week. Depending on the track of the low, it could bring increased rainfall chances to the region. 3. Multiple rounds of tidal flooding are expected later this week, with tidal flooding potentially beginning as early as Tuesday evening. && .DISCUSSION... KEY MESSAGE 1...A frontal boundary south of the region will keep rain chances around through mid-week, especially across southern portions of the area. The cold front that crossed through our region Sunday Night is expected to stall to our south today, and remain there through Tuesday. It continues to look like it will lift a little closer to our region Monday Night into Tuesday morning as a warm front, but remain just south of the area. Due to the closer proximity, and a mid level short wave trough, mean that that period will have the highest chance for rain across our region. Given that our low will be on the cool side of the front, showers are going to be the main mode of any precipitation. However, isolated, embedded thunderstorms will be possible over Delmarva, particularly during the day on Tuesday. For Wednesday into Thursday, the front should again be on the move southward, lessening rain chances across the area. Confidence is high that temperatures will be below normal starting Tuesday. In fact, temperatures will likely struggle to get out of the 60s areawide through most of this week. KEY MESSAGE 2...A closed mid-level low ejecting from the Ohio Valley is expected to lead to the development of a surface low off the Eastern Seaboard during the middle and latter parts of this week. Depending on the track of the low, it could bring increased rainfall chances to the region. Most of the models came into better agreement on the track and the evolution of the coastal low through Thursday. Through this time, the center of the low should stay far enough off shore that rain chances across our region will be very low, except at immediate coastal areas. However, it looks to be a deep and intense low, so expect a large pressure gradient, even for inland areas, and thus breezy to windy conditions. For coastal areas, we could get close to wind advisory thresholds, particularly later in the day on Wednesday through Thursday. Friday into the weekend, some models have this becoming a cutoff low and retrograding eastward. Notably though, this solution is primarily with the deterministic, physical equation models. Several ensemble members and some of the main AI models depict this low continuing northeastward. All that being said, the forecast, particularly the rain and wind forecast, is very uncertain from Friday onward. KEY MESSAGE 3...Multiple rounds of tidal flooding are expected later this week, with tidal flooding potentially beginning as early as Tuesday evening. There will be a prolonged period of onshore flow at the coast continuing through at least Thursday, and may continue through the weekend. This, combined with increasing astronomical tides ahead of the full moon on Saturday, means that multiple rounds of tidal flooding for the Atlantic coast, Delaware Bay, and tidal Delaware river are likely. With the latest guidance, the earliest that we may see minor tidal flooding is with the Tuesday afternoon/evening high tide, and that appears most likely for the Atlantic coast and Delaware Bay from Barnegat Inlet southward. That being said, there remains uncertainty in how high the tidal anomalies will be by Tuesday Afternoon. The highest confidence in tidal flooding occuring is Wednesday and Thursday. Through this period, we could even see moderate tidal flooding. Of special note with this set up, the prolonged nature of the onshore flow tends to result in the highest tidal anomalies on back bays, instead of ocean front. Consequently back bays including Barnegat Bay and Shrewsbury River in New Jersey and the Indian River Bay in Delaware could see the worst impacts with this tidal flooding. Friday into the weekend, there is considerably less confidence, as it will be highly dependent on how the coastal low evolves through this period. If the low retrogrades closer to the coast as some models are showing, the coastal flooding is likely to continue through the weekend. For the Chesapeake Bay, the expected wind direction tends to limit tidal flooding concerns, but it will need to be watched if persistent easterly flow at the mouth of the Chesapeake. Currently, tidal flooding is unlikely through Wednesday Night. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. For KPHL, KPNE, KILG, KTTN, KABE, and KRDG...rain is mostly east of the TAF sites, so expect prevailing VFR conditions through this morning and afternoon. MVFR ceilings may linger through 09Z at KPHL, KPNE, and KILG. Near or after 00Z, more MVFR ceilings, and an additional round of rain will likely move through the region. Once the MVFR ceilings move in, expect that to be the controlling factor in flight category through Monday Night. Northeasterly winds around 10kt, though occasional gusts up to 20 kt will be possible. For KMIV and KACY...rain will be moving out by 08Z. Expect some temporary breaks to VFR conditions as the rain moves out. However, as the winds become more northeasterly, MVFR ceilings could redevelop and continue through much of the TAF period. At this point, not confident that the clouds around 2k ft AGL will be at least BKN through the day time, so in the TAFs, have both sites going to VFR by 12Z and then going back to MVFR by 00Z, but will be watching trends closely through the day. Outlook... Tuesday...Sub-VFR conditions likely in periods of rain and low clouds. Wednesday through Friday...While uncertainty is high, sub-VFR conditions will remain possible at times in rain or low clouds. Gusty northeast winds are possible. && .MARINE... Small Craft Advisory conditions are expected starting early to mid afternoon on the Atlantic Coastal Waters, and Tuesday Morning for the Delaware Bay. Even though this is an unusual wind direction for SCA conditions on the Bay, multiple models depict a several hour period of wind gusts at or above 25 kt, so have issued the SCA for the Bay from Tuesday morning through Tuesday Night. Gales are looking increasingly likely for at least a period of the mid to late week. Consequently, a gale watch has been issued for all of the Atlantic forecast zones starting Tuesday Evening, and for the Delaware Bay starting Wednesday Morning. The watch currently goes through the day on Thursday, when we have the most confidence in gale conditions. Gale conditions may linger into Friday and Saturday depending on the evolution of the coastal low, which is uncertain in this time frame. Rip Currents... Monday... There is a MODERATE risk for dangerous rip currents Today thanks to the onshore component of the persistent northeasterly winds. Breaking waves in the surf zone will be around 2 to 4 feet. Tuesday...Northeasterly winds strengthen to 20 to 30 mph with wave heights in the surf zone building to 3 to 5 feet. As a result, there is a HIGH risk of rip currents both for the New Jersey shore and the Delaware Beaches. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...High Risk for Rip Currents from Tuesday morning through Tuesday evening for NJZ014-024>026. DE...High Risk for Rip Currents from Tuesday morning through Tuesday evening for DEZ004. MD...None. MARINE...Small Craft Advisory from 5 AM Tuesday to 6 AM EDT Wednesday for ANZ430-431. Gale Watch from Wednesday morning through Thursday afternoon for ANZ430-431. Small Craft Advisory from 11 AM this morning to 6 PM EDT Tuesday for ANZ450>455. Gale Watch from Tuesday evening through Thursday afternoon for ANZ450>455-480>483-485. && $$ DISCUSSION...Cooper/Hoeflich/WFO PHI AVIATION...Cooper/Fitzsimmons/WFO PHI MARINE...Cooper/Fitzsimmons/WFO PHI