Marine Weather and Tide Forecast for Forest Heights, MD

KEY MESSAGES
- 1) After a break Wednesday, showers and thunderstorm chances increase Thursday and Friday.

- 2) Numerous showers and thunderstorms Saturday with lingering showers Sunday. Turning cooler and dry for next week.

DISCUSSION
KEY MESSAGE 1...After a break Wednesday, showers and thunderstorm chances increase Thursday and Friday.

The diffuse cold frontal zone still bisects the area this afternoon, with dew points in the lower 60s in the northwest and lower 70s in the east. Water vapor imagery shows some drying from Highland to Anne Arundel Counties to the north. These gradients support CAM depictions of a few additional showers possibly forming across the southern tier of counties through the remainder of the afternoon. While a thunderstorm can't be ruled out, poor mid level lapse rates may cap updrafts.

Surface high pressure builds eastward from the Ohio Valley tonight. Some clearing takes place, though more uncertainty exists across southern portions of the forecast area. Where skies are clear, fog may form, especially in the river valleys.
The high will slide across the area Wednesday, providing dry conditions. Temperatures will be near or slightly above average.

As a shortwave trough pivots through the Great Lakes and St.
Lawrence Valley, the next cold front will approach the area Wednesday night. The chance for showers, and perhaps a thunderstorm, will increase the second half of the night from the north. Although timing remains a bit uncertain, the cold front looks to enter the area Thursday morning, then slowly cross southward through Thursday night. Questions regarding early day precip and cloud cover lend to uncertainty in how much instability builds Thursday afternoon, though a few stronger storms are certainly possible given increased flow aloft and lift along the front. AI/ML severe probabilities have been consistent showing higher values across southeastern portions of the CWA The bulk of 12Z NWP guidance is in general agreement with the strongest convective signals near or just south of the southern CWA border. Temperatures will depend on clouds and frontal position, with a range from the upper 70s to near 90 possible across the CWA

There could be a relative break in some areas on Friday if high pressure over the St. Lawrence valley shoves the front to the south. Relatively speaking, rain chances will be higher farther south, closer to the frontal zone. Troughing will begin to amplify Friday night, with low pressure perhaps developing and/or lifting northeastward from the Carolinas. Overrunning moisture will spread northward late in the day and overnight, though there remain questions on how quickly and how far north and west the rain reaches.

KEY MESSAGE 2...Numerous showers and thunderstorms Saturday with lingering showers Sunday. Turning cooler and dry for next week.

The longwave pattern is forecast to amplify significantly this weekend into next week as trough digs across the Great Lks and OH Valley. This will drive a pair of cold fronts across the area Sat and Sun providing focus for showers and thunderstorms. Saturday looks like the more active and more unstable day as shortwave energy moves across. By Sunday, the first cold front should have pushed the deep moisture and instability to the south limiting the coverage and intensity of showers.

As trough axis shifts east of the area Sunday night or Monday, expect a cooler and drying trend to start the new work week.

AVIATION /18Z TUESDAY THROUGH SUNDAY/
Light northwest flow continues through Wednesday. While a pop up shower remains possible near CHO this afternoon, probabilities appear to be diminishing as drier air works in from the NW.
Clearing skies and light to calm winds can be expected tonight as high pressure builds eastward. CHO and MRB may see some fog development. Some cloudiness could linger near CHO, but if it clears, LIFR conditions could develop. Winds will gradually turn more southwesterly Wednesday afternoon with VFR conditions expected.

Rain may approach the TAF sites ahead of a cold front late Wednesday night, with more numerous showers and possible thunderstorms Thursday afternoon and evening. Some lower ceilings are possible, especially around MRB Thursday morning.
Showers may linger at CHO Thursday night and Friday, along with potential lower ceilings.

Depending on the placement of a stationary front and track of low pressure along it, showers, thunderstorms, and low ceilings are possible at times Friday night through Sunday.

MARINE
Light winds are expected through Friday. North to northwest winds continue into Wednesday before briefing becoming southerly by late Wednesday. A brief enhancement is possible along the Chesapeake Bay Wednesday evening due to channeling, but prospects of advisory conditions are marginal at best. Winds then shift back to the northwest and north Thursday and Friday as a cold front pushes southward.

A pop up thunderstorm is possible mainly south of Annapolis and Dahlgren this afternoon or early evening. A cold front may bring additional thunderstorms Thursday into Friday.

Small Craft Advisory conditions are possible Saturday and again Sunday night into Monday morning as a series of fronts and low pressure centers move near the waters. Additional thunderstorms are possible Saturday.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.