Marine Weather Net

Chesapeake Bay from Drum Point MD to Smith Point VA Marine Forecast








10 - 15

The Marine Weather Forecast In Detail:
ANZ534 Forecast Issued: 133 PM EDT Fri Sep 29 2023

This Afternoon...N Winds 15 Kt With Gusts To 20 Kt. Waves 2 To 3 Ft. Isolated Showers.
Tonight...N Winds 15 Kt With Gusts To 20 Kt. Waves 3 Ft.
Sat...N Winds 15 Kt With Gusts To 20 Kt. Waves 3 Ft.
Sat Night...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 2 To 3 Ft.
Sun...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 2 To 3 Ft.
Sun Night...N Winds 10 Kt. Waves 2 Ft.
Mon...N Winds 10 To 15 Kt...Becoming Ne 5 To 10 Kt. Waves 1 To 2 Ft.
Tue...Ne Winds 5 To 10 Kt. Waves 1 Ft.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
216pm EDT Fri September 29 2023

Low pressure will move well out to sea tonight while an upper- level trough passes through the area. High pressure will gradually build into the area from the north and west through the middle of next week.

Near Term - Through Tonight
An upper-level trough will move into the area from the west through this evening before moving off to the east later tonight. Low pressure will remain offshore while surface high pressure remains to the north.

Low-level moisture will continue to wrap around the low offshore in a northerly flow, causing low clouds to continue across northern MD into the Washington and Baltimore Metropolitan areas. Farther southwest, some sunshine has developed with the low clouds mixing out. A few showers and perhaps even a thunderstorm are possible this afternoon into this evening across the Allegheny and Potomac Highlands into central Virginia due to limited instability that has developed from the sunshine and colder air aloft associated with the upper-level trough. A few showers are also possible across northeastern MD as moisture wraps around low pressure offshore.

Highs will range from the lower to middle 60s across northeastern MD where plenty of clouds (and perhaps patchy drizzle) are expected, to the upper 60s/lower 70s around the Washington Metro area, to the mid and upper 70s in central Virginia as well as the valleys of the Potomac Highlands.

A northerly flow is expected to continue tonight as high pressure draws closer from the north. However, low-level moisture will likely remain trapped underneath the subsidence inversion, resulting in more low clouds for most areas. Some radiation fog is possible in the valleys of the Potomac Highlands into the central Shenandoah Valley where there will be less low clouds to start this evening. A few showers and drizzle are still possible, mainly across northeastern MD and near the Bay where low-level moisture will be deepest.

Short Term - Saturday Through Sunday Night
The trough that passes through our area tonight will develop into a cutoff low well off the New Jersey coast for Saturday. High pressure will continue to slowly build toward the area from the north. A north to northeast flow will continue to usher in some more low-level moisture, which will cause a stratocu deck for much of the time near and northeast of the Potomac River. Any low clouds/fog should give way to more sunshine farther south and west. Highs will range from the upper 60s to lower 70s across northeastern MD to the mid and upper 70s in the valleys of the Potomac Highlands as well as central Virginia.

High pressure will continue to build toward the area Saturday night, bringing dry conditions. Clouds should dissipate as drier air finally moves in from the north, but some fog is possible overnight.

The high will continue to slowly build overhead for Sunday through Sunday night. More sunshine is expected Sunday and this will allow for a warmer afternoon with highs in the mid 70s to near 80 for most areas. Dry conditions will persist Sunday night as well.

Long Term - Monday Through Thursday
Surface high pressure and a strong upper level ridge located overhead will provide the long term period with warm and dry conditions through midweek. As the upper level ridge erodes and an upper level trough pivots into the area, precipitation chances return to the forecast for the Alleghenies late Thursday. Otherwise, dry conditions are expected areawide with high temperatures topping out in the upper 70s for most with some reaching 80 degrees. Overnight low temperatures will be in the 50s and 60s for most.

High pressure will continue to build toward the waters through Saturday while low pressure remains offshore. A north to northeast flow is most likely during this time and an SCA remains in effect for the Bay and lower Tidal Potomac River.

An SCA (Small Craft Advisory) is in effect Saturday night for the middle portion of the Bay south of Drum Point and the lower Tidal Potomac River. The SCA (Small Craft Advisory) may need to be extended into Sunday. Farther north, the gradient should be weaker. High pressure will settle over all the waters Sunday night.

No precipitation is forecast for Monday or Tuesday with winds remaining below SCA-criteria both days.

Tides / Coastal Flooding
Tidal anomalies have fallen (but remain elevated) due to the northerly winds and this trend should continue through Saturday. A Coastal Flood Advisory is in effect through the high tide cycle this evening for Washington DC and through the high tide cycle tonight for St Marys Counties.

Water levels should remain below minor flood thresholds Saturday into Saturday night. However, an onshore flow will develop by Sunday lasting into early next week and more minor flooding is possible during this time.

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...Coastal Flood Advisory until 11pm EDT this evening for DCZ001. MD...Coastal Flood Advisory until 5am EDT Saturday for MDZ017. VA...None. WV...None.

Small Craft Advisory until 6pm EDT Saturday for ANZ530>532- 539-540. Small Craft Advisory until 6am EDT Sunday for ANZ533-534-537- 541-543.