Tidal Potomac from Cobb Island MD to Smith Point VA Marine Forecast
|Rest Of Today...S Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Showers This Afternoon.|
|Tonight...S Winds 5 To 10 Kt. Waves 1 Ft. Rain. Areas Of Fog. Vsby 1 To 3 Nm.|
|Tue...Se Winds 5 Kt. Waves Less Than 1 Ft. Rain Likely. Areas Of Fog. Vsby 1 To 3 Nm.|
|Tue Night...Ne Winds Around 5 Kt. Waves 1 Ft Or Less.|
|Wed...Se Winds 5 To 10 Kt. Waves 1 Ft. Showers Likely.|
|Wed Night...Sw Winds 10 To 15 Kt. Gusts Up To 20 Kt. Waves 1 To 2 Ft. A Chance Of Showers.|
|Thu...W Winds 10 To 15 Kt. Waves 2 Ft.|
|Fri...W Winds 10 Kt. Waves 2 Ft.|
Area Forecast Discussion|
National Weather Service Baltimore MD/Washington DC
954am EST Monday Feb 24 2020
Low pressure will track into the Ohio Valley tonight into Tuesday, with another area of low pressure and its associated cold front crossing the region Wednesday night. Canadian high pressure will build overhead for the end of the week.
.NEAR TERM Through Tonight
Low pressure will track into the Midwest through this afternoon and evening while surface high remains offshore. A longwave upper-level trough will remain over the central CONUS while a weak upper-level ridge axis moves off to the east.
A southerly flow ahead of the low and behind the high will continue to usher in mild conditions. Max temps will be in the mid to upper 50s for most areas.
A southwest flow throughout all levels of the atmosphere will continue to usher in more moisture through tonight. Clouds will continue to increase through midday, and the cloud deck will gradually lower tonight.
Low-level dry air should hang on through this evening, keeping most places dry. However, a few sprinkles/light showers are possible this afternoon/evening as a weak shortwave at the mid- levels of the atmosphere passes through the area behind the departing ridge axis.
Isentropic lift will increase overnight and low-level moisture will also increase. This will allow for rain to overspread the area. Rainfall amounts should be on the light side (around a tenth to a quarter inch) due to weak forcing since the low and the mid and upper-level dynamics will remain west of the Appalachians.
Short Term - Tuesday Through Wednesday Night
Steady rain is expected to taper off by midday Tuesday as low pressure fills and mid-level dry slot moves in. Low overcast will remain, though, with potential for areas of fog and drizzle due to light easterly convergent/upslope flow.
Second area of low pressure is expected to form along the Blue Ridge and develop northeastward as it tracks from the Mid-Atlc to southern New England by Thu morning. Widespread showers and possible thunderstorms are expected Wednesday afternoon into Wed evening along the front and ahead of negatively tilted upper trough. While there is a non-zero chance of severe t-storms, wind fields aloft and shear values are not anywhere close to what they were during the Fri Feb 07 tornado event that day. Cdfnt will sweep through the area by 03Z Thu with showers ending east of the Appalachians. Showers will turn quickly into snow showers over the mtns with sub-advisory accumulations expected. Turning brisk late Wednesday night into Thursday as pressure gradient tightens and upper troughing deepens and establishes across the East.
Long Term - Thursday Through Sunday
A surface low pressure system will exit our region to the northeast with its associated cold front moving to our east out of the Atlantic Ocean on Thursday. Winds will become westerly at the surface leading to cooler air advecting into our region. A west- northwest to northwesterly flow is forecast to form at 850mb leading to the full layer dropping below freezing. The westerly flow is expected to lead to the formation of upslope snow showers along and west of the Allegany Mountain range. The deep layer of cold air suggests that a few inches of snow will be possible for areas along and west of the Allegany Mountains.
A closed off 500 mb low will be positioned to our north over New England and eastern Canada. This upper level low will remain in place Thursday afternoon through this weekend. High pressure will build to our south with winds mainly out of the west to variable at times Friday through this weekend. Models are forecasting a shortwave to drop down from the closed off 500 mb low and move through our region late Friday and into Saturday morning. This shortwave is forecast to provide enough lift to kick off some precipitation in our region. Since temperatures throughout the layer are expected to remain below freezing, this precipitation would likely fall as snow showers. There remains a lot of uncertainty on snow amounts but light snow can't be ruled out Friday into Saturday. The upper level low will slowly shift northeastward away from our region. Cold and dry air is forecast to remain in place with near to below temperatures possible for this upcoming weekend.
Ridging looks to return for the first week of March with temperatures rising near to slight above normal for the time of the year.
Winds will be below SCA (Small Craft Advisory) most of the time through 18Z Wed. However, southerly winds may be close to SCA (Small Craft Advisory) criteria late this afternoon into tonight across the middle portion of the Bay and lower Tidal Potomac River.
Winds will strengthen late Wednesday or Wednesday night behind a cold front. Strong SCA (Small Craft Advisory) conditions are expected behind the cold front through Thursday. Low risk for gales still exist Thursday. T-storms Wednesday afternoon and evening may require SMWs.
As a surface low lifts northeast out of our region, the pressure gradient will be strong enough that Small Craft Advisories may be needed Thursday into Friday.
NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None. MARINE...None.