Marine Weather Net

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




5 - 10


10 - 15



The Marine Weather Forecast In Detail:
ANZ537 Forecast Issued: 736 PM EDT Sat Oct 23 2021

Tonight...W Winds 10 Kt...Becoming N Late This Evening And Overnight. Waves 1 Ft.
Sun...Se Winds 5 To 10 Kt. Waves 1 Ft.
Sun Night...S Winds 10 To 15 Kt With Gusts To 25 Kt. Waves 2 Ft.
Mon...S Winds 10 Kt With Gusts To 20 Kt. Waves 2 Ft.
Mon Night...S Winds 5 To 10 Kt. Waves 1 To 2 Ft. Showers Likely With A Chance Of Tstms.
Tue...Nw Winds 10 To 15 Kt With Gusts To 25 Kt. Waves 2 Ft. A Chance Of Showers.
Tue Night...Nw Winds 10 To 15 Kt With Gusts To 25 Kt. Waves 3 Ft.
Wed...Nw Winds 10 To 15 Kt. Waves 1 To 2 Ft.
Thu...E Winds 5 To 10 Kt...Becoming S After Midnight. Waves 1 Ft. A Chance Of Showers. Winds And Waves Higher And Visibilities Lower In And Near Tstms.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
311pm EDT Sat Oct 23 2021

High pressure will gradually build across the region tonight into Sunday. A warm front will cross the region late Sunday and Sunday night. A strong cold front will then cross the region Monday night into Tuesday with low pressure lingering nearby into Tuesday night. High pressure will briefly return Wednesday before another system approaches by late Thursday into Friday.

Near Term - Through Sunday
A very weak frontal boundary is pushing southeastward across the Appalachians, helping to generate some showers across PA and northern MD. Some may extend further south as the afternoon progresses, but much of the area and much of the time will be dry for the rest of the day.

There isn't much push of wind behind the front, so the air mass change is minor. However, relatively dry air already in place will allow lows to drop into the 40s for most areas overnight with some clearing.

Sunshine will be more common Sunday, but some warm advection clouds may return as a warm front approaches from the southwest. The sun should allow temps to creep up a few more degrees, but still close to normal for this time of year.

Short Term - Sunday Night Through Monday Night
Warm front will push north across the region late Sunday/Sunday night, with increased clouds, stronger southerly flow (at least, on the waters) and milder temps. Could be a stray shower but most of the time looks dry.

Behind this front, much warmer air will envelop the area for Monday ahead of the next cold front. Temps likely push well into the 70s and could crack 80 in places. Clouds will be increasing from west to east, and western areas could see some showers or even a t-storm later in the day, but bulk of the area looks dry most of the day.

Things get much more interesting Monday night as the strong front and upper trough swings into the area. Shear is quite strong (over 40 knots) though instability may be very limiting. Nevertheless, there is a risk of stronger storms given the forcing, and the Storm Prediction Center has placed parts of the area in a slight risk. This may be expanded across more of the region as confidence grows.

Long Term - Tuesday Through Saturday
Rain showers are possible Tuesday morning mainly along and east of I- 95 as the main storm system continues moving east. Additional upslope rain showers are possible into Tuesday afternoon/evening across the Allegheny Highlands as an additional disturbance moves through. Areas east of the higher terrain should just remain cloudy Tuesday afternoon due to enough downsloping.

Transient ridging builds in late Tuesday. There could be some frost/freeze mainly along/west of I-81 Tuesday night depending on how quickly clouds move out of the region, although the growing season has already ended for Garrett County and will be ending soon for the remaining counties west of I-81.

What is certain amount both deterministic and ensembles is the late Wednesday through Friday timeframe looks unsettled across the eastern US. However, uncertainty arises regarding the evolution of the upper level pattern and a lee cyclone developing off the Rockies. Some guidance has a closed upper level low meandering over the eastern US while other guidance has broad troughing. Late Thursday currently looks like the best opportunity for steadier rain.

Light winds presently despite a weak cold frontal passage will become southerly and strengthen on Sunday. By Sunday night, widespread SCA (Small Craft Advisory) expected across most waters except for the narrower, more protected ones such as the upper tidal Potomac. Even this won't last and by Monday, all waters likely see southerly gusts of 20-30 knots. Stronger front Monday night likely brings some gusty showers and this could result in special marine warnings.

SCA (Small Craft Advisory) conditions are likely Tuesday with gales possible as northwest winds approach gusts to 30 knots. Winds remain out of the northwest Wednesday, but still could gust to SCA (Small Craft Advisory) levels.

Tides / Coastal Flooding
Whlie water levels are low presently, increasing southerly flow ahead of the next cold front Monday night will lead to rising water levels. We may reach minor flood thresholds, especially at the more sensitive sites, by late Monday/Monday night, though uncertainty is high and am not currently forecasting it. Anomalies should drop thereafter as winds become northerly.

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

Small Craft Advisory from 10pm Sunday to 6am EDT Monday for ANZ539. Small Craft Advisory from 6pm Sunday to 6am EDT Monday for ANZ531>533-540>542. Small Craft Advisory from 3pm Sunday to 6am EDT Monday for ANZ534-537-543. Small Craft Advisory from 2am to 6am EDT Monday for ANZ530.