Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
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828 FXUS61 KPHI 302259 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 659 PM EDT Sun Jun 30 2024 .SYNOPSIS... A cold front will slide through our region through tonight. High pressure builds in Monday through Tuesday before moving offshore Wednesday. A surface trough arrives on Thursday as a cold front may approach from the northwest Friday. && .NEAR TERM /THROUGH MONDAY/... Will cancel portions of Severe Thunderstorm Watch 489 as the threat has ended in portions of southeast Pennsylvania and northern New Jersey. For Philadelphia, northern Delaware, and portions of southern New Jersey, will extend Severe Thunderstorm Watch 489 until 9 pm. Severe Thunderstorm Watch 491 for Delmarva and southern New Jersey remains in effect until 11 pm. Severe Thunderstorm Watch 489 remains in effect until 7 pm. Will allow the Heat Advisory that was in effect until 7 pm for portions of New Jersey, southeast Pennsylvania, and Delmarva to expire. Showers and clouds have resulted in cooler temperatures. Southerly flow continues ahead of an approaching cold front. Strong to severe thunderstorms continue to move through southern New Jersey, the Delaware Valley, and Delmarva. SB CAPE values are down to 2500 to 3500 J/kg, and the severe threat swill be focused on southern portions of the forecast area through this evening. Damaging winds and localized flash flooding are the main threats. Frequent lightning strikes will also occur in the strongest storms. Cold front passes through the region after midnight or so and storms will taper off. A much drier airmass spreads into the region after midnight as dew points drop into the 50s by daybreak. Northwest winds will pick up to around 15 mph with gusts up to 20 mph late tonight before increasing to 15 to 20 mph with gusts up to 25 mph Monday morning. Winds diminish Monday afternoon. Much more pleasant weather for Monday with below normal highs in the upper 70s to around 80. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... High pressure will remain the dominant feature through Wednesday. The mostly pleasant and tranquil conditions will continue Tuesday and Wednesday. Highs on Tuesday will be near normal, mainly in the low-mid 80s. However, with dew points forecast to remain in the 50s, another pleasant day looks to be on tap. Lows Tuesday night will be a touch warmer as well, mainly in the low-mid 60s. As the high shifts further east on Wednesday, expect low level southerly return flow to usher in a modest warming trend, but conditions should remain quite pleasant. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Summary...Approaching trough and cold front will be responsible for rain chances through the long term. Few changes from the previous forecast. Synoptic Overview...A Canadian upper-level trough will push the ridge southward some Thursday and Friday. At the surface, a trough arrives Thursday with a cold front approaching from the northwest Friday. Thursday (Independence Day) through Sunday...Southerly flow becomes more established leading to hot and humid conditions through the weekend. The influence of a Canadian upper-level trough will start to approach during Thursday, however the timing and amplitude of this trough is less certain. As of now, the main trough is more toward the Midwest and therefore the associated cold front may be slow to approach our area late in the week. There may be a pre- frontal trough in our vicinity Thursday into Friday and this may provide enough focus amid a destabilizing air mass to initiate some convection. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...CIGs lifting to VFR, but sub-VFR in SHRA/TSRA with conditions improving from NW (KRDG/KABE) to SE (KMIV/KACY) starting at 02Z and through 04Z or so. Severe thunderstorms likely, and should a severe storm pass over a terminal, wind gusts in excess of 50 kt could occur. Heavy rain will also result in VSBYs 1SM or less. Cannot rule out large hail as well. Non-thunderstorm winds will be out of the SW at 10 to 15 kt with gusts up to 20 kt, turning NW by this evening at 5 to 10 kt. Winds increase late tonight to 10 to 15 kt with gusts up to 20 kt after 09Z. Moderate confidence overall. Monday...VFR. NW winds 15 to 20 kt with gusts up to 25 kt, diminishing to 10 to 15 kt after 18Z. High confidence. Outlook... Tuesday and Wednesday...VFR with no significant weather. Thursday and Friday...Sub-VFR conditions possible with chances (25-35%) for SHRA and TSRA, especially in the afternoon. && .MARINE... S winds ahead of an approaching cold front will result in 10 to 15 kt winds with gusts up to 20 kt into this evening. Will go ahead and cancel the Small Craft Advisory as conditions are not quite meeting SCA criteria. Winds shift to the NW behind the passing cold front tonight. Winds increase to 15 to 20 kt with gusts up to 25 kt on all waters late tonight through midday Monday. Will go ahead and hoist a new SCA from 09Z to 17Z Monday to cover this. Thunderstorms on the waters will result in wind gusts in excess of 40 kt, VSBY restrictions in heavy rain, and frequent lightning strikes. Large hail also possible. Storms should begin to taper off after midnight, though lingering showers and thunderstorms may continue on DE ocean waters into daybreak Monday. Outlook... Tuesday through Friday...Winds and seas are expected to be below SCA criteria. Rip Currents... Monday...Behind a cold front, N winds will average 15 to 20 mph with gusts up to 25 mph in the morning, then will diminish to 10 to 15 mph in the afternoon. Due to these elevated winds and breaking waves of 1 to 2 feet, there is a MODERATE risk for the development of dangerous rip currents for the Jersey Shore. For Delaware Beaches, winds will back slightly to the NW and will be a bit lighter. This results in a LOW risk for the development of dangerous rip currents for Delaware Beaches. On Tuesday, much more tranquil conditions with E to NE winds 5 to 10 mph. As a result, there is a LOW risk for the development of dangerous rip currents at the Jersey Shore and at Delaware Beaches. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 5 AM to 1 PM EDT Monday for ANZ430- 431-450>455. && $$ SYNOPSIS...AKL/Gorse/Johnson NEAR TERM...MPS SHORT TERM...AKL/Johnson LONG TERM...AKL/Gorse/Johnson AVIATION...Johnson/MPS MARINE...Johnson/MPS