Marine Weather Net

Tidal Potomac from Cobb Island MD to Smith Point VA Marine Forecast




15 - 20


10 - 15


10 - 15

The Marine Weather Forecast In Detail:
ANZ537 Forecast Issued: 337 AM EST Mon Jan 20 2020

Rest Of The Overnight...Nw Winds 20 Kt With Gusts To 25 Kt. Waves 3 Ft.
Today...N Winds 15 To 20 Kt With Gusts To 25 Kt. Waves 3 Ft.
Tonight...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 3 Ft.
Tue...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 2 To 3 Ft.
Tue Night...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 2 Ft.
Wed...N Winds 5 To 10 Kt. Waves 1 To 2 Ft.
Wed Night...Ne Winds 5 To 10 Kt. Waves 1 Ft.
Thu...E Winds Around 5 Kt. Waves 1 Ft Or Less.
Fri...E Winds 5 To 10 Kt. Waves 1 To 2 Ft. A Chance Of Rain Through The Night.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
357am EST Monday Jan 20 2020

An expansive area of high pressure will translate eastward from the northern Plains during the first half of the week, becoming centered overhead by Wednesday. The high will move offshore during the second half of the week, then low pressure will approach from the central United States for Saturday.

.NEAR TERM Through Tonight
Strong Arctic high pressure is located over the northern Plains this morning. A trough axis is moving southward from Pennsylvania. Once this trough axis moves through, any remaining upslope snow showers will likely taper to flurries and end by early afternoon as moisture becomes shallow. For the rest of the area, there is little significance other than some passing clouds and continued gusty winds. Those winds are producing wind chills in the teens (or lower) this morning, and these values will fail to rise above the 20s for many areas today. Air temperatures will top out in the 30s for most, while staying in the teens/20s at increasing elevation.

The surface high will build toward the Ohio Valley tonight. The best radiational cooling conditions will be in the western valleys where the gradient will be weaker. Given projected dew points, a few single digits could occur in these locations, but most of the area will be in the teens, with 20s in the cities and close to the tidal waters.

Short Term - Tuesday Through Wednesday Night
Upper troughing will gradually lose its influence Tuesday and Wednesday, allowing the surface high to spread eastward. Ridging aloft will be overhead by Wednesday. Dry conditions are expected, and other than a batch or two of passing cirrus, skies should be mainly clear as well. Daytime highs will moderate a bit each day, with 40s becoming common again by Wednesday. Winds will become less of a factor as well. Lows will respond more slowly given favorable radiational cooling conditions continuing. Teens and 20s are expected both Tuesday and Wednesday nights.

Long Term - Thursday Through Sunday
High pressure will be in control on Thursday while mid to upper level trough deepens over the central CONUS, resulting in a mid- level cut-off low by Friday. At the surface, low pressure system will develop, but it is uncertain on location as deterministic and ensemble means develop it either over the Midwest or over the Tennessee Valley. This is followed by an ENE track that will increase the chances of precipitation over our region Friday night. The low pressure will then either move over us from the SW or will transfer its energy from the Great Lakes into a coastal low on Saturday. Either solution brings precipitation in form or rain or snow (mainly over higher elevations) between Friday night and Saturday night as the low deepens offshore. The low will move away from us Saturday night into Sunday with some lingering precipitation. Sunday night into Monday guidance suggests a shortwave trough could bring us some additional precipitation.

Gusty northwest winds are continuing today, resulting in blowout tides (-1 ft MLLW or lower) this morning from Annapolis northward. Given a trough axis crossing, winds remain elevated at this early hour, and the Small Craft Advisory remains in effect for all waters through noon today. It's possible this could be extended into the afternoon, but didn't feel confident to make such a small adjustment at this time.

A tight pressure gradient across the Bay will result in continued gusty northerly winds tonight, with the advisory continuing for the wider waters south of Pooles Island, including the lower tidal Potomac. Have this advisory ending at 10am Tuesday as high pressure gets closer and winds diminish. There's some potential an advisory could be needed through portions of Tuesday night (with or without a gap Tuesday afternoon) for the wider waters near southern Maryland due to continued northerly channeling. The high will be overhead by Wednesday, with light winds prevailing through Wednesday night.

Sub-SCA (Small Craft Advisory) conditions expected Thursday into late Friday with high pressure in control. SCA (Small Craft Advisory) conditions possible Friday night into Saturday night.

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None.
Small Craft Advisory until 10am EST Tuesday for ANZ531>534- 537-539>543. Small Craft Advisory until 6pm EST this evening for ANZ530- 538. Small Craft Advisory until noon EST today for ANZ535-536.