Marine Weather and Tide Forecast for Philadelphia, PA

KEY MESSAGES
1. Heavy rainfall possible with showers and thunderstorms this afternoon into this evening; localized flooding possible.

2. Hot and humid conditions into early next week. Heat Advisory issue for portions of the area for Thursday and Friday.

DISCUSSION

KEY MESSAGE 1...Heavy rainfall possible with showers and thunderstorms this afternoon into this evening; localized flooding possible.

A warm front will continue to lift northward across the area this afternoon into this evening. As a couple of short wave/vorticity impulses move across the area, scattered showers and thunderstorms are expected to continue to develop and move northward across the area. With PW values of around 1.75-2.0+ inches, any showers or thunderstorms will produce very efficient rainfall rates of 1 inch or more. This could lead to some localized flooding, especially in urbanized and poor drainage area. The Weather Prediction Center has a Marginal Risk (1 out of 4) for Excessive Rain. While showers and thunderstorms will wane through the evening for most areas, portions of northeast Pennsylvania and northern New Jersey could continue to see precipitation into the overnight hours.

KEY MESSAGE 2...Hot and humid conditions into early next week.
Heat Advisory issue for portions of the area for Thursday and Friday.

Once the warm front lifts north of the area, our area will be under the influence of high pressure located offshore of the Atlantic seaboard, which will lead to well established return flow. This will keep hot and humid conditions in place for the next several days. A Heat Advisory has been issued for all areas who's criteria is heat index values of 100-104 degrees. This includes portions of eastern Pennsylvania, much of New Jersey except the far southern counties, as well as New Castle Delware.
The Heat Advisory will run from 10 am Thursday and continue through 8 pm Friday.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Rest of Today...Conditions will vary between VFR and MVFR, with a few instances of IFR when heavy showers and thunderstorms move across a TAF site. PHL, PNE, and TTN are the most likely for this to happen. Once showers end, VFR condition should prevail for the rest of the afternoon. Low confidence overall.

Tonight...Many areas may start out as VFR this evening before MVFR conditions develop overnight as stratus and light fog may develop. A few showers may also be possible overnight, especially for ABE and RDG. Low confidence overall.

Thursday.. MVFR conditions may begin to day, before an improvement to VFR is expected for later in the morning into the afternoon. Isolated to scattered showers and thunderstorms will be possible for portions of northeast Pennsylvania and northern New Jersey. Moderate confidence.

Outlook...

Friday through Monday...Periods of sub VFR possible in afternoon and evening SHRA/TSRA generally Friday and Saturday.

MARINE
Tonight-Thursday...Conditions are expected to remain below Small Craft Advisory levels.

Outlook...

Friday through Sunday...Overall, winds and seas should be below SCA criteria however in the afternoon both Friday and Saturday, anticipated isolated to scattered afternoon and evening showers and thunderstorms which could briefly increase winds and seas.

Rip Currents...

For Today, winds becoming southeasterly near 10 mph. Breaking waves in the surf zone of 1-3 feet are forecast with a medium period swell. Given the more onshore component for most of the Jersey Shore, maintained a MODERATE risk for the development of dangerous rip currents. Breaking waves look to be a little lower for the Delaware Beaches with a more parallel wind therefore went with a LOW risk for the development of dangerous rip currents.

For Thursday, south to south-southwest winds increase to 10-20 mph.
Despite the increasing wind and it becoming more parallel to the coast and the breaking waves forecast to be a little lower, a longer period swell may arrive. Opted to go with a MODERATE risk for the development of dangerous rip currents for the Jersey Shore, and a LOW risk for the development of dangerous rip currents for the Delaware Beaches.

PHI WATCHES/WARNINGS/ADVISORIES
PA...Heat Advisory from 10 AM Thursday to 8 PM EDT Friday for PAZ054-055-060>062-070-071-101>106.
NJ...Heat Advisory from 10 AM Thursday to 8 PM EDT Friday for NJZ001-007>010-012-013-015-017>020-027.
DE...Heat Advisory from 10 AM Thursday to 8 PM EDT Friday for DEZ001.
MD...None.
MARINE...None.