textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

No significant changes to today's forecast.

All Coastal Flood Advisories have expired. No further widespread tidal flooding is expected, though some spotty minor tidal flooding remains possible within back bays.

Added the Delaware Beaches to the High Risk for the development of rip currents for today.

Added a key message for Monday.

KEY MESSAGES

1. Windy and warm today with a chance for scattered showers and thunderstorms. A few storms later this afternoon could be strong to severe.

2. A High Risk for the development of rip currents is in place for the Jersey Shore and Delaware Beaches today.

3. A system moves through sometime Monday into Monday Night, likely bringing widespread rainfall to the area.

DISCUSSION

KEY MESSAGE 1...Windy and warm today with a chance for scattered showers and thunderstorms. A few storms later this afternoon could be strong to severe.

A few showers this morning are expected, mainly north and west of the I-95 corridor. This is from decaying convection well off to the west. Not expecting much from this initial round of showers however. If anything, the morning cloud cover and showers will limit the severe risk for later this afternoon.

Low pressure moves through Ontario today and into Quebec. This will drag a cold front through our region, with scattered showers and thunderstorms developing out ahead of the front. The general trend continues to be a faster progression with the shortwave, and lesser coverage in storms. The Slight Risk was maintained however given strong kinematics aloft, steep low- level lapse rates, and some instability. This will result in any storm that does develop being capable of producing damaging wind gusts. The limiting factors for today will be the better forcing being off to the north, and instability being limited by the morning showers and cloud cover. The timeframe to watch will be this afternoon and evening, from around 1 PM to 8-9 PM or so.

Thinking the bigger story for today will be the gusty winds. A strong gradient sets up with a deepening sub-1000 mb area of low pressure moving by to the north and a strong Bermuda High offshore. This will result in breezy to even brisk southwest winds, which is quite unusual for this time of year. Sustained winds will be around 15 to 25 MPH with gusts of 30 to 40 MPH. Peak gusts should fall just below Wind Advisory criteria, around 45 MPH.

The final storyline for today will be the one-day surge in temperatures. After a few days of seasonal temperatures, strong warm-air advection sets up for today with brisk southwesterly flow. This will result in temperatures surging into the upper 80s to low 90s. This will only last for today though, with more seasonable temperatures expected this weekend in the wake of today's frontal passage.

Key Message 2...A High Risk for the development of rip cornets is in place for the Jersey Shore and Delaware Beaches today.

A Rip Current Statement has been issued for today for the Jersey Shore and Delaware Beaches

For today, south-southwest winds will be increasing to around 15 to 25 mph with gusts as high as 25 to 35 mph in the afternoon. There will be a southeasterly 4 to 6 foot swell at 6 to 7 seconds. Breaking wave heights of 3 to 5 feet expected as well. As a result, with strong winds in a shore parallel or offshore direction, and 3 to 5 foot breakers, elected for a HIGH risk for the development of rip currents at all beaches.

For Friday, west-southwesterly winds generally 5-15 mph. There will be a south-southeasterly swell of 3 to 5 feet at around 7 seconds. Breaking wave heights of 1 to 3 feet are anticipated. Have opted for a MODERATE risk for the Jersey Shore and a LOW risk for Delaware beaches for the development of dangerous rip currents, where flow is more offshore. Did consider downgrading the Jersey Shore given tranquil conditions, but will have to see how quickly windy and rough conditions in the surf zone taper off.

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

KEY MESSAGE 3...A system moves through sometime Monday into Monday Night, likely bringing widespread rainfall to the area.

Medium range guidance continues to hint at a stretch of unsettled weather to start next week. The main question will be the track of the low pressure as it moves through the region, which will have some consequence in specific impacts. The main takeaway though is that Monday is currently looking quite wet, with some thunderstorms likely mixed in as the area of low pressure moves through, mainly in the afternoon. Still a lot of uncertainty though, but it looks increasingly likely that some sort of system moves through to start next week.

AVIATION /10Z THURSDAY THROUGH MONDAY/

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

Today...Primarily VFR. Seeing some marine stratus around KACY resulting in IFR conditions, but that should mix out by 13z. Model guidance continues to back off on coverage in showers and thunderstorms later today. Cannot rule it out completely, but think the chance is low enough (15-30%) to leave thunder out at this time. Any thunderstorms would come through between 16z-22z, from west to east. Main story will be winds today. Winds start out of the south/southwest, increasing to 10-15 kt and gusts 20-25 kt. Winds go more southwesterly between 16z-18z with 15-20 kt winds and 25 to 35 kt gusts through the afternoon and early evening. Moderate confidence overall.

Tonight...VFR. A frontal passage will result in winds going more west/northwesterly, around 10 kt through most of the night. Moderate confidence.

Friday..VFR. West/northwest wind gusts could get near 20 kt at times.

Outlook...

Friday Night...VFR. No significant weather

Saturday...VFR. West/northwest wind gusts around 20 to 25 kt.

Saturday Night through Sunday...VFR. No significant weather.

Monday...Sub-VFR conditions expected with periods of rain and scattered thunderstorms.

MARINE

A Small Craft Advisory is in effect until Midnight tonight. Winds pick up out of the southwest with gusts around 30 kt through most of the day with seas of 4 to 7 feet. A few gusts near 34 kt cannot be ruled out, especially in nearshore areas and inlets.

Winds and seas quickly diminish tonight, and sub-SCA conditions are expected by daybreak Friday.

Outlook...

Friday through Sunday... winds and seas continue to diminish with no marine hazards anticipated.

Monday...Advisory conditions likely developing, with gusts over 25 kts and seas over 5 feet.

Rip Currents...See Key Message 2 above.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...High Risk for Rip Currents through this evening for NJZ014-024>026. DE...High Risk for Rip Currents through this evening for DEZ004. MD...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ430-431- 450>455.