Marine Weather and Tide Forecast for Riviera Beach, MD

NEAR TERM /THROUGH SATURDAY/
Current (as of 930 PM) radar imagery shows an arc of heavy rainfall and thunderstorms extending southwestward from Charles County into the Central Virginia Piedmont. This activity is slowly progressing off toward the east. Further north, activity is more isolated to scattered to the north of I-66, and also slowly progressing off toward the east.

The environment this evening is very conducive for heavy rainfall in any thunderstorms, with around 1000-2000 J/kg of MLCAPE, very moist profiles through a deep layer, high freezing levels, and precipitable water values near 2 inches. Rainfall rates as high as 2 inches in 20 minutes were observed with thunderstorms as they moved through Fairfax County earlier.
Isolated to scattered instances of flash flooding will continue to be possible over the next few hours, especially to the south and east of the earlier mentioned convective line (Central Virginia Piedmont to southern Maryland). A Flash Flood Watch remains in effect for much of the area through 2 AM. Portions of this Watch may be able to be canceled early.

While heavier rain and thunderstorms should wind down over the next few hours, showers and/or drizzle may linger on and off through the night. Temperatures will remain mild overnight, with lows in the mid 60s to lower 70s.

SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/
A cold front will stall across the central zones of our region through the day Saturday. An upper level low will move closer to the area from the west. A lull in shower and any thunderstorm activity more likely through Saturday morning with and thereafter the fog. Another heavy round of showers and thunderstorms is expected Saturday afternoon and evening. There is still some uncertainty as to exactly where this will setup, but latest guidance continues to suggest areas south and west of the Potomac River as the areas most likely to get the strongest convection. All the ingredients are there for a flash flood threat. Will continue to monitor, because the position of the front will be vitally important as to exactly where the strongest convection will be. For areas to the northeast of the boundary. A few showers and a thunderstorm are still possible, especially late in the day into the evening as stronger convection upstream propagates into the area.

The upper level low will shear apart as it moves into the area Sunday, but latest guidance shows the boundary pushing a little farther south and west. This is most likely in response to subsidence associated with a departing jetmax in the northern stream, causing high pressure to strengthen off the New England Coast. The threat for heavy rain is most likely across central Virginia into the Allegheny Highlands, but that can change if the location of the front is off. Will continue to monitor.

LONG TERM /MONDAY THROUGH FRIDAY/
The stalled front will remain nearby in our region through the day on Monday with cool marine air remaining in place for most areas. The boundary will dissipate and move north Tuesday as a warm front and high pressure over the Atlantic will likely control the weather pattern for the middle of next week with a return of hotter and humid conditions. Unsettled conditions will likely persist during this time with chances for showers and thunderstorms. Perhaps the best chance for stronger storms will be Thursday as a cold front approaches from the west.

AVIATION /01Z SATURDAY THROUGH WEDNESDAY/
Thunderstorms are progressing through the area this evening. As of 930 PM, storms have moved off to the south and east of IAD, DCA, MRB, and CHO, with showers still in the vicinity of BWI and MTN. Chances for showers and storms should continue to wind down through the remainder of the evening.

Low clouds and areas of fog/drizzle are likely to develop late tonight behind a stalling front that moves into the area. There is still some uncertainty as to exactly where the boundary will set up, but latest indications are that most areas will end up in the marine air for Saturday through Monday. This means that low clouds and subVFR conditions are likely most of the time with IFR/subIFR conditions possible, especially at night into the morning hours each day. Unsettled conditions will continue with the likelihood for showers and perhaps a few storms. The best chance for storms will be around KCHO, KMRB and KIAD Saturday afternoon and evening and KCHO for Sunday afternoon and evening. However, storms are possible everywhere.

More low clouds and fog will likely hang around through Tuesday morning, but cigs/vsbys should improve as the backdoor boundary dissipates and moves northward.

MARINE
A southerly flow will increase into this evening, but winds should remain below SCA criteria. Thunderstorm coverage will increase through this evening. Gusty winds associated with storms may warrant Special Marine Warnings.

A stalling front will slide across the central areas for later Saturday through Monday night. An easterly flow will bring low clouds and areas of fog, and the likelihood for showers and perhaps a thunderstorm will persist. Winds should be below SCA criteria. The boundary will dissipate Tuesday and a southerly flow will develop for the middle portion of next week.

LWX WATCHES/WARNINGS/ADVISORIES
DC...Flood Watch until 2 AM EDT Saturday for DCZ001.
MD...Flood Watch until 2 AM EDT Saturday for MDZ013-016-017-504.
VA...Flood Watch until 2 AM EDT Saturday for VAZ037>039-050-051- 053>057-502-527.
WV...None.
MARINE...None.