textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

1. The Severe Thunderstorm Watch is no longer in effect for portions of southeast Pennsylvania and northern New Jersey, but has been extended until 10 pm for portions of southern New Jersey and Delmarva.

2. The HIGH rip current risk is no longer in effect.

3. Showers/storms now look to linger into Tuesday as the frontal system now looks slower to depart.

KEY MESSAGES

1. Low pressure continues to pass through the region this evening, and the severe thunderstorm and flash flooding threat is now focused on portions of southern New Jersey and Delmarva. Additional rounds of showers and storms now are likely for Tuesday.

2. The HIGH risk of rip currents for coastal Ocean, Atlantic, and Cape May counties is no longer in effect.

3. Another cold front is expected to approach the region late this week, bringing more chances for showers and storms.

DISCUSSION

KEY MESSAGE 1...Low pressure continues to pass through the region this evening, and the severe thunderstorm and flash flooding threat is now focused on portions of southern New Jersey and Delmarva. Additional rounds of showers and storms now are likely for Tuesday.

Low pressure will be moving across southern PA then through NJ en-route to Long Island going through tonight. While another round of showers and thunderstorms may impact at least the I-95 corridor later this evening, the main threat for severe weather is now focused on portions of southern New Jersey and Delmarva.

Getting towards the mid evening period, the severe weather threat should be diminishing but the low looks to be very slow moving across the area through the overnight meaning more showers and possible storms will be likely. It's for this reason that we have the Flood Watch going through the night to 6 AM Tuesday.

For Tuesday, the big change in the forecast is that the system now looks to get hung up over the area with the latest indications actually being for a new low to develop near near Delmarva. This will occur as another piece of energy moves around the base of the upper trough over the east. This will result in more rounds of showers and storms that could once again be on the heavier side by the afternoon. Near the warm sector over southern Delmarva, we can't rule out some storms becoming severe and the SPC now has a MARGINAL risk for severe storms just getting into Sussex County Delaware.

Low pressure with it's associated showers/storms should finally move out through Tuesday night.

KEY MESSAGE 2...The HIGH risk of rip currents for coastal Ocean, Atlantic, and Cape May counties is no longer in effect.

The Rip Current Statement for the HIGH risk for the development of dangerous and life threatening rip currents is no longer in effect. However, continue to only go in the water at beaches where lifeguards are present and beaches are open.

On Tuesday, winds will be out of the south to southwest around 10 mph, turning to the north at 10 to 15 mph with gusts up to 20 mph in the afternoon. Breaking waves will be 1 to 3 feet with a light southeasterly swell with a period around 6 seconds. As a result, there is a LOW risk for the development of dangerous and life threatening rip currents for the Jersey Shore and Delaware Beaches.

On Wednesday, winds will be light and variable in the morning, turning south around 10 mph in the afternoon. Breaking waves will be 1 to 2 feet with a light southeast swell with a period around 7 seconds. As a result, there is a LOW risk for the development of dangerous and life threatening rip currents for the Jersey Shore and Delaware Beaches.

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

KEY MESSAGE 3...Another cold front is expected to approach the region late this week, bringing more chances for showers and storms.

Another cold front is expected to approach our region late in the week (likely crossing through our region Friday into Saturday). More showers/storms are likely beginning as early as late day Thursday and then continuing Friday. Southwesterly flow ahead of the front should allow for plenty of moisture advection ahead of the rain chances. However with the best forcing more centered north of the region, that could limit how widespread significant rain is with this event. As for what hazards to expect with this event, that will be highly dependent on the timing of the showers and storms, which is still uncertain.

The front may linger nearby next weekend and if this occurs it would keep chances for shower/storms going, especially in the afternoon/evening hours. There is uncertainty regarding this though.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

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

Tonight...A round of SHRA/TSRA will now primarily impact KMIV/KACY through 02Z or so. Another round of SHRA with isolated TSRA possible from 02Z to 06Z or so. Otherwise, CIGs will lower to MVFR, and then IFR and possibly LIFR after 06Z with MVFR VSBYs in BR. The strongest TSRA is currently just north of KACY. Winds will become LGT/VRB after 06Z. Moderate confidence overall.

Tuesday...Sub-VFR conds in the morning in BR and stratus, then another round of SHRA with scattered TSRA will impact most terminals from late morning through late afternoon with MVFR/IFR conds. Winds become N around 10 kt from late morning on. Moderate confidence.

Tuesday night...VFR. Light N to NW winds. High confidence.

Outlook...

Wednesday...VFR. No significant weather.

Thursday through Saturday...Chances for shower/storms return (30 to 50 percent chances) beginning late day Thursday and these could bring brief restrictions.

MARINE

Small Craft Advisory in effect through tonight with southerly wind gusts increasing to 30 knots with seas building to 4 to 6 feet. Some gusty thunderstorms will be possible this evening.

After a lull, another period of SCA conditions will be possible late day Tuesday into Tuesday night due to gusty N/NW winds.

Outlook...

Wednesday through Saturday...Sub SCA conditions.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Flood Watch until 6 AM EDT Tuesday for PAZ070-071-101>106. NJ...Flood Watch until 6 AM EDT Tuesday for NJZ008>010-012-013- 015>019. DE...Flood Watch until 6 AM EDT Tuesday for DEZ001. MD...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ430-431. Small Craft Advisory until 6 AM EDT Tuesday for ANZ450>455.