Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
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721 FXUS61 KPHI 131338 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 938 AM EDT Thu Jun 13 2024 .SYNOPSIS... Weak surface high pressure centered offshore will still remain in control through tonight. A cold front crosses our region Friday afternoon into Friday night. High pressure then builds in over the region and continues into the beginning of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 935 AM, the low-level moisture is increasing mostly across the coastal plain where the dew points are into the 60s. These may lower some though this afternoon with vertical mixing. This increased moisture should result in at least some cumulus development through the afternoon. Plenty of warming on land will add to a sea breeze through the day. No significant changes were made with this update. Otherwise, weak surface high pressure is centered offshore however it remains extended over our region and will still influence our weather tonight. We will have some warm air advection today with a south to southwest surface flow. Highs in the 80s are anticipated for most areas, with it cooler along the coast with a sea breeze and also in the higher terrain. There is some indication of some upper-level shortwave energy being in place this afternoon/evening. While the forecast continues to have no precipitation included given the rather weak forcing and very low probability, a few isolated showers cannot be ruled out entirely later today. Mainly quiet conditions continue tonight with overnight lows in the 60s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... A sharp cold front approaches the region Friday. Timing of the cold front`s passage will largely be the driver in what happens across the region. Latest guidance is still indicating that the highest chance of timing would bring the front through late afternoon/early evening. That timing would start to show support for organized showers and thunderstorms with the potential for severe weather. The full suite of hi res convective-allowing models depicts modest instability developing during the afternoon, around 1000 J/kg of MUCAPE, approaching 18-21z with 30-35kts of 0-6km shear and sufficient LI`s. The highest shear totals are currently being forecast to occur slightly to the north however the soundings currently suggest from roughly Trenton north that organized severe weather has at least a 15% chance with severe thunderstorm wind gusts being the main threat. As a result, SPC has placed areas north and west of the I-95 corridor in a Slight Risk for severe weather with the rest of the region in a Marginal Risk. In addition, with the surge of PWAT increasing between 18z-00z close to 1.75" any storm could be capable of producing heavy rainfall. While the soil moistures are relatively dry over the past few weeks, poor drainage and impervious surfaces could be subject to flooding. Concerning temperatures, warm air advection should be in place across the region through Friday until the cold front pushes through. This leads highs before the front Friday warming into the upper 80s to low 90s, and then down into the upper 50s to low 60s Friday night. High pressure builds in from the north and west on Saturday, ushering a rather tranquil weekend. Highs during the afternoon will be in the low-to-mid 80s with nighttime lows dipping into the mid 50s to right around 60. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Behind the cold front the synoptic pattern sets up with a building ridge through the weekend. Heights will quickly rise across the Mid Atlantic with a mid level ridge dominating through at least the early portion of next week. While the surface high will start to push offshore, all that does is setup southerly return flow leading to warm temperatures being advected north for several days in a row. While global guidance is still rather spread out with just how hot it will get across the region next week, guidance across the board has been fairly consistent with the building high pressure and increasing heat through the week with a high likelihood of temperatures lingering well into the 90s for a number of days. At this point, it is certainly not too early to start thinking about your cooling options for next week. For anyone hoping for temporary relief from precipitation chances, at the moment, chance for this remain rather low. While there are some pieces of shortwave energy tracking through the region during the week, the overall chance for showers is fairly capped (10-15%) due to the very weak forcing from these shortwaves. At this point, a large number of ensembles show the ridge starting to deamplify but still holding on till late in the week. This would allow for some weakening in max temps during the day but not much. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...VFR. South to southwest winds increasing to around 10 knots, with some local gusts up to 20 kts possible this afternoon. Moderate confidence. Tonight...VFR. South-southwest winds around 5 knots. High confidence. Outlook... Friday...Sub-VFR possible with showers and thunderstorms during the afternoon/evening. Saturday through Monday...VFR. && .MARINE... Today and tonight, southerly winds increase to 10-15 knots with gusts to around 20 knots this afternoon/evening. Seas 2-4 feet. Marine headlines are largely not anticipated. Otherwise, fair weather. Outlook... Friday through Friday night...SCA conditions possible Friday due to winds gusting up to 20-25 kts and seas of 3-5 feet. A chance of thunderstorms later Friday and Friday night. Saturday through Monday...No marine headlines expected. Winds up to 10-15 kts with seas 2-4 feet. Fair weather. Rip Currents... Southwest flow 5-10 mph becomes south 10-15 mph with occasional gusts up to 20 mph today. Breaking waves will average 1 to 2 feet. Primarily a 1-2 ft 7-8 second short period swell from the E-SE. As a result, there is a LOW risk for the development of dangerous rip currents today. On Friday, south winds increase to around 15 mph with 20 to 25 mph gusts. The flow will be a bit more onshore for most of New Jersey as opposed to northern New Jersey and Delaware. That said, strongest winds will be across northern New Jersey. Additionally, guidance shows a 1 ft 9-10 second longer period swell from the SE to SSE developing by the afternoon. As a result, there is a MODERATE risk for the development of dangerous rip currents for New Jersey beaches where the coastline is more perpendicular or oblique to the longer period swell. LOW risk for the development of dangerous rip currents for the Delaware beaches. Breaking waves will once again average 1 to 2 feet. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...MJL NEAR TERM...Gorse/Wunderlin SHORT TERM...Deal/MJL LONG TERM...Deal/MJL AVIATION...Gorse/MJL/Wunderlin MARINE...Gorse/MJL/Wunderlin