textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1. A low chance for severe thunderstorms over Delmarva this afternoon.

2. Drier and more seasonable conditions return for the end of the week into the weekend.

DISCUSSION

KEY MESSAGE 1...A low chance for severe thunderstorms over Delmarva this afternoon.

Some showers and storms are moving through this afternoon as an area of low pressure rides along a stalled boundary planted just to the south of the area. One final afternoon of unsettled weather as a cold front moving in from the northwest sweeps in and high pressure moves in behind the front tonight.

The first round of showers and storms has largely moved offshore early this afternoon. However, the incoming trough and associated cold front at the surface could trigger another round of thunderstorms. Strongest forcing will be in the vicinity of the stalled boundary which will be to our south and west. Higher instability and shear will also be displaced from our region. However, over towards Maryland, more favorable conditions exist for the development of some clusters of thunderstorms, some of which could be severe. The CAMs for this afternoon do indicate that these clusters could cross the Chesapeake and move into Delmarva, potentially bringing some damaging wind gusts. SPC maintains a Slight Risk (2/5) that clips the Eastern Shore and southern Delaware, with a majority of the Eastern Shore and Delaware in a Marginal Risk (1/5). This is about right as the bigger threat for severe weather will be to our south and west, but some storms could make it into the southern part of the area. For New Jersey and Pennsylvania, things should be more tranquil this afternoon, though cannot rule out a few showers or isolated thunderstorms as the cold front moves in from the northwest. Not expecting any severe weather today north of the Mason-Dixon line.

Rainfall amounts across Delmarva will be up to around a half inch, with localized totals higher if thunderstorms move over any certain area. Not expecting any flooding concerns.

KEY MESSAGE 2...Drier and more seasonable conditions return for the end of the week into the weekend.

High pressure moves in for the end of the week as an Omega Block sets up over the central CONUS. High pressure will remain in control through at least Sunday with dry conditions expected. Some guidance is hinting at an upper level low swinging down for the start of next week, which could bring some unsettled weather, but confidence is low in the forecast beyond Sunday.

Temperatures through the extended look to be near or even a little below normal for late May/early June. It still should be a pleasant start to meteorological summer though.

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Today...Some lingering MVFR conditions from the first round of showers and storms early this afternoon but conditions will become primarily VFR for the remainder of the afternoon and evening as further showers and thunderstorms should stay off to the south. Westerly winds around 10 kts. Moderate confidence.

Tonight...VFR as a dry cold front moves through, resulting in winds going more northwesterly between 02z-05z, around 5-10 kt. High confidence.

Thursday...VFR. Northwest winds around 10 kt with gusts near 20 kt. High confidence.

Outlook...

Thursday Night through Monday...VFR. No significant weather.

MARINE

Sub-SCA conditions expected through Thursday. Winds will be around 10 kts, beginning southwesterly this afternoon, shifting to a northwesterly direction for tonight as a cold front passes, continuing to be out of the NW for Thursday. Scattered showers and thunderstorms expected for today, especially south of Little Egg Inlet on the ocean and within Delaware Bay.

Outlook...

Thursday Night through Monday...No marine headlines expected. Slight chance (15-20%) of needing an SCA on Saturday Night as seas could near 5 feet.

Rip Currents...

For Thursday and Friday, a northwest to north wind 10-15 mph Thursday will become west to southwest on Friday. A medium period 7 to 8 second swell and breaking waves in the surf zone of around 2 feet are forecast. This will result in a LOW risk for the development of dangerous rip currents for both the New Jersey Shore and Delaware Beaches.

Ocean water temperatures are in the 50s to low 60s. These chilly water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water.

For specific beach forecasts, visit weather.gov/beach/phi

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...None.