Marine Weather and Tide Forecast for Charles, MD

KEY MESSAGES
1. Scattered showers and thunderstorms will continue into the early overnight period tonight.

2. A Flood Watch has been issued for Tuesday into Wednesday as an impactful system arrives across the region.

DISCUSSION
KEY MESSAGE 1... Scattered showers and thunderstorms will continue into the early overnight period tonight.

Scattered showers and thunderstorms have developed across the northern Middle Atlantic region this afternoon as increasing heat and moisture have arrived along with a few upper short waves. We are not expecting widespread severe weather, but with the possibility of strong downpours and some damaging winds could occur in a few spots, the Marginal risk for severe storms remains across our area for that reason.

The storms will be slow moving, so localized flooding is possible through the tonight period as well. A slight risk for excessive rainfall remains for Delaware tonight. The activity is expected to decrease after sunset.

KEY MESSAGE 2... A Flood Watch has been issued for Tuesday into Wednesday as an impactful system arrives across the region.

As the upper heights continue to drop and summertime warmth and humidity continue...Tuesday looks to feature the more widespread showers and thunderstorms. The H5 height falls and jet dynamics aloft will favor convective development nearly all day as surface low pressure develops just to our west. This will keep a steady stream of warm, moist air pumping into the area and keeping the environment conditionally unstable despite cloud cover. PWats will rise to near 2" by the end of the day. Some models suggest we could have a stalled or slow moving frontal boundary across the central or northern portion of the forecast area, which could act as a focusing mechanism for heavy rainfall.
Heavy rain leading to flash flooding could end up being a bigger concern and greater impact than the severe thunderstorm threat.

The latest outlooks from WPC show most of our area in a SLIGHT risk for excessive rainfall, but northern NJ has a MODERATE risk for excessive. A flash flood watch has been issued for Tuesday and into Wednesday. As for severe weather, the southern half of the area including Delmarva, south NJ and metro Philadelphia have a SLIGHT risk for severe thunderstorms while areas to the north are in a MARGINAL risk. Damaging winds are the primary threat with thunderstorms on Tuesday.

The low pressure looks to be offshore to our east by Wednesday.
There is some uncertainty with regards to how fast its effects diminish across the area. We'll continue with scattered showers and storms again by afternoon, at least across our NJ and PA zones, but the severe thunderstorm threat will be lower given lower instability. Flash flooding is possible Wednesday too.

AVIATION /00Z TUESDAY THROUGH SATURDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Tonight...VFR expected for most of the night, before lowering to MVFR after 08-10Z. Isolated showers or thunderstorms may linger into the early evening, but not expecting any widespread restrictions. Patchy fog possible overnight along with a few showers mainly for KRDG/KABE. Light south winds around 5 kt or less. Moderate-low confidence overall.

Tuesday...Prevailing MVFR conditions expected for much of the day, with occasional instances of both IFR and VFR conditions possible. Multiple rounds of showers and thunderstorms expected beginning late morning and continuing through the afternoon.
South winds generally around 10-15 kt with gusts up to 20-25 kt possible in the afternoon. Locally gusty and erratic winds possible in any thunderstorm. Low confidence overall.

Outlook...

Tuesday night...Periods of MVFR/IFR conditions likely with showers and thunderstorms continuing into the evening and overnight hours.

Wednesday through Wednesday Night...Restrictions possible with lingering showers and low clouds.

Thursday through Saturday...VFR. No significant weather expected.

MARINE
Sub-SCA conditions expected through Tuesday morning with southerly winds around 10-20 kt and seas 2 to 3 feet. Scattered showers and tstms into the early overnight period tonight.

Outlook...

Tuesday Afternoon through Tuesday Night...A Small Craft Advisory is in effect for all marine zones as south/southwest winds around 20-25 kt and seas of 3 to 5 feet are expected. Showers ans tstms expected.

Wednesday through Wednesday Night...SCA conditions possible (40-50%)
especially on the northern waters as seas near 5 feet.

Thursday through Friday...No marine headlines expected.

Rip Currents...

For Tuesday, southerly flow will increase as the day progresses causing winds to increase from around 10 to 15 mph to around 15 to 25 mph in the afternoon with gusts up to 30 mph possible.
Multiple swell groups generally around 2 to 4 feet are expected.
With only 1 day prior to the full moon phase and average swell periods around 5-7 seconds, opted to continue with a MODERATE risk for dangerous rip currents for both the Jersey Shore and Delaware Beaches.

For Wednesday, winds will vary depending on the beaches where the southern Jersey Shore and Delaware Beaches will generally have west winds around 10 to 15 mph where northern Jersey Shore beaches will have south winds around 10 to 20 mph. Breaking wave heights will average between 1 to 3 feet. With the Full Moon Phase occuring on Wednesday, have opted to go with a MODERATE risk for dangerous rip currents at all beaches.

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

PHI WATCHES/WARNINGS/ADVISORIES
PA...Flood Watch from Tuesday morning through Wednesday afternoon for PAZ054-055-060>062-070-071-101>106.
NJ...Flood Watch from Tuesday morning through Wednesday afternoon for NJZ001-007>010-012>020-026-027.
DE...Flood Watch from Tuesday morning through Wednesday afternoon for DEZ001.
MD...None.
MARINE...Small Craft Advisory from noon to 8 PM EDT Tuesday for ANZ430- 431.
Small Craft Advisory from noon Tuesday to 6 AM EDT Wednesday for ANZ450>455.