Marine Weather Net

Tidal Potomac from Key Bridge to Indian Head MD Marine Forecast


REST OF TONIGHT

W
WINDS
5 KNOTS

MON

W
WINDS
5 - 10
KNOTS

MON NIGHT

NW
WINDS
5 - 10
KNOTS

TUE

NW
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ535 Forecast Issued: 937 PM EST Sun Jan 26 2020

Rest Of Tonight...W Winds 5 Kt. Waves Less Than 1 Ft.
Mon...W Winds 5 To 10 Kt. Waves 1 Ft.
Mon Night...Nw Winds 5 To 10 Kt. Waves 1 Ft.
Tue...Nw Winds 5 To 10 Kt. Waves 1 Ft.
Tue Night...Nw Winds 5 To 10 Kt. Waves 1 Ft.
Wed...Nw Winds 5 Kt. Waves Less Than 1 Ft.
Wed Night...N Winds Around 5 Kt. Waves 1 Ft.
Thu...Ne Winds Around 5 Kt. Waves 1 Ft Or Less.
Fri...Light Winds. Waves 1 Ft.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
918pm EST Sunday Jan 26 2020

Synopsis
Low pressure will linger over northern New England and the Canadian Maritimes through Tuesday. A weak low pressure will pass south of the region on Monday. High pressure will build across the Northeast and Mid-Atlantic Wednesday through Friday. A storm system may affect the region next weekend.

Near Term - Through Monday
Latest analysis depicts low pressure over northern New England, with northwesterly flow over our region. Another area of low pressure is located in the lower Mississippi Valley. Aloft, a closed low is centered over the St. Lawrence Valley within a broad trough covering the eastern two thirds of the country. Another shortwave is located over the southern Plains with another closed low over the Dakotas.

Through Monday, all these features will progress east (or in the case of the Dakota low, southeast) while the overall pattern remains the same, with the trough over the eastern US and northwesterly flow at the surface. Clouds will become a bit less dominant this evening as insolation wanes, diminishing mixing east of the mountains, though along and west of I-81 clouds will persist, with continued light snow showers along the Allegany Front. Late tonight, the approaching shortwave south of the region will help clouds redevelop east of the mountains, so most areas will turnout mostly cloudy, but no precipitation is expected beyond the Allegany Front. Lows tonight will stay up a bit compared to normal thanks to the clouds, with temps near freezing in much of the region.

The system in the Lower Mississippi Valley will pass south of the region on early on Monday while the system in the Dakotas will do likewise late in the day. This will bring intervals of clouds mixed with sunnier periods on Monday, but clouds will continue to dominate west of I-81 thanks to the continued west to northwest flow. However, except for yet more light snow showers will occur along the Allegany Front, the region will remain dry. Enough sun is likely to bring highs back into the 40s in most of the area, with near 50 expected near and south of DC.

Short Term - Monday Night Through Tuesday Night
Some clearing is expected east of the I-81 corridor Monday night and Tuesday as the northwest flow wanes while the low in the Canadian Maritimes pulls away into the Atlantic. There is a push of cold advection on its back side, however, so temps will drop a bit despite the increased sun, and there may still be a few snow showers along the Allegany Front during this time as weaker upslope flow will linger. Another weak system passing aloft Tuesday night will usher in another push of cold advection, allowing lows to drop into the 20s for most of the region by dawn Wednesday, but this should be a drier air mass and the snow showers along the Allegany Front should finally end.

Long Term - Wednesday Through Sunday
Wednesday and Thursday are likely to remain mostly dry, as high pressure builds south out of Canada and gradually moves offshore by late Friday. A few upper-level disturbances will move through the area during this time, but none look to bring impactful weather to the region. The first of which will move by well to our south on Wednesday, but another disturbance will move overhead out of the northern/central Plains. This could result in some light precipitation on Wednesday night. The best chance for any precipitation would be in eastern WV and western VA, but even that chance is pretty low. However, any precipitation in this period would likely be snow, given temperatures in the 20s. Highs on Wednesday and Thursday will be slightly below average, with highs only in the low 40s and overnight lows in the mid 20s.

Meanwhile, attention turns to the weekend, where a significant storm system may impact the area. At this time, model solutions are far too spread out to lock on to any one solution, but will give a brief synoptic overview of what features are at play. The upper level pattern associated with the subtropical jet becomes very active early to middle of the week, both over our area, and out west. The upper-level energy over our area was already discussed. However, another, more potent, piece of upper-level energy will dive out of the Pacific northwest into the southwest Tuesday through Thursday, and eventually into the southern Plains by Friday. As this piece of energy moves towards the Gulf of Mexico, low pressure will form along the Gulf Coast on Friday. Meanwhile, the polar jet is also very active, with several shortwaves diving out of the Canadian prairies in the same general time frame. This is a pretty good setup for a potential coastal low pressure system this weekend. Now, the uncertainty, as always, lies in where the storm will track when it does form. A wide range of possibilities is being depicted by the computer guidance. Yes, there is the potential for a winter storm, but it could also very well be a cold rain. Some guidance even takes it completely offshore to our south, and doesn't bring it up the coast. So, definitely want to see better consistency, which should come in a couple of days, when the features in question can be better sampled by upper air data collections. Additionally, with high pressure pushing offshore, rather than staying in place over the northeast, cold air will be in question. It will be cold, but will it be cold enough to snow if we get a coastal low? That remains a big question as well. For now, this is mainly something to keep an eye on until we have better confidence.

Marine
Relatively weak gradient will maintain sub-SCA (Small Craft Advisory) winds over the waters through Monday. System pushing off shore Monday night into Tuesday may allow winds to strengthen to SCA (Small Craft Advisory) levels.

No marine hazards are expected Wednesday or Thursday, as high pressure builds overhead.

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None. MARINE...None.