Marine Weather Net

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


REST OF TONIGHT

NE
WINDS
20
KNOTS

SUN

N
WINDS
15 - 20
KNOTS

SUN NIGHT

N
WINDS
15 - 20
KNOTS

MON

NW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
ANZ537 Forecast Issued: 936 PM EST Sat Nov 16 2019

GALE WARNING IN EFFECT THROUGH SUNDAY AFTERNOON
Rest Of Tonight...Ne Winds 20 Kt With Gusts To 35 Kt. Waves 5 Ft. A Slight Chance Of Rain.
Sun...N Winds 15 To 20 Kt With Gusts To 30 Kt. Waves 5 Ft.
Sun Night...N Winds 15 To 20 Kt With Gusts To 30 Kt. Waves 4 Ft.
Mon...Nw Winds 10 To 15 Kt With Gusts To 25 Kt. Waves 2 To 3 Ft.
Mon Night...W Winds 5 Kt. Waves Less Than 1 Ft.
Tue...Nw Winds 5 Kt. Waves Less Than 1 Ft.
Tue Night...Nw Winds 5 To 10 Kt. Waves 1 Ft Or Less.
Wed...Nw Winds 10 To 15 Kt. Waves 1 To 2 Ft.
Thu...Sw Winds 10 To 15 Kt. Waves 1 Ft. A Chance Of Showers Through The Night.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
836pm EST Sat Nov 16 2019

Synopsis
A strong area of low pressure will linger off the Carolina coast through Sunday, slowly inching to the northeast. Meanwhile, a strong area of high pressure shifts east into the Canadian Maritimes, pushing cooler air into the region. High pressure will then build into the region from the west into the middle portion of the week before another cold front approaches towards the end of next week.

Near Term - Until 6am Sunday Morning
Coastal low pressure will strengthen off the southeast Coast tonight while high pressure remains over New England. The high will wedge south into the Mid-Atlantic during this time.

An easterly flow at the low-levels will allow for some moisture from the Atlantic to overrun the surface northerly flow in place. This will allow for an increasing stratus deck across most areas. Min temps will range from the 20s across most locations to the lower 30s near and east of I-95. Did lean toward the warmer side of guidance across eastern areas thinking that cloud cover and a gradient wind should keep temps up. Therefore, the coldest temperatures are expected in the valleys west of the Blue Ridge Mountains where cloud cover will hold off the longest.

Short Term - 6am Sunday Morning Through Monday Night
A steady northerly breeze expected on Sunday, but will be less intense than Saturday, as low pressure slides by well offshore. However, this will be the closest pass of this coastal low, so could see some rain along the Chesapeake Bay, but best chances are still off to the east. Can't rule out a passing shower though. Temperatures likely a couple degrees cooler on Sunday, with more clouds around.

Flow turns a little more northwesterly Sunday night, with more clouds around as well, so temperatures may moderate a bit, with lows in the low to mid 30s. Low-end rain chances continue along the Chesapeake Bay, but find it hard to believe anything makes it any farther west than that, as the coastal low remains well offshore.

By Monday morning, any chances for precipitation should be shifting off to the northeast. Some rain is possible over northeastern MD, as a piece of shortwave energy swings through, which is also what is pushing the coastal low farther away from the area. However, in the wake of this shortwave, some upslope showers are possible in the normal areas along/west of the Allegheny Front. These could mix with some snow during the morning hours, but should primarily be rain, given temperatures mostly above freezing a few hours after sunset. Slight chance for that at this point though, and best chance for any snow will be for the highest elevations.

Precipitation should be over with across the entire forecast area by Monday evening. Though, am carrying slight chance POPs in the far northwest portions of the CWA, as there is some uncertainty as to just how quick the coastal low moves away. Clouds likely linger into Monday night, with lows in the low to mid 30s.

Long Term - Tuesday Through Saturday
The base of a mid to upper level trough will pivot through the region Tuesday and Tuesday night, delivering a fair amount of cloud coverage but not much in the way of precipitation with a weak and diffuse frontal boundary nearby. Temperatures will remain near normal for the middle of November.

By Wednesday, high pressure over the Southeast will build northward across the Mid-Atlantic through the first half of Thursday before shifting offshore. This will lead to continued dry conditions and near or slightly above normal temperatures. An area of low pressure originating near the Four Corners region Wednesday looks poised to track into the Great Lakes on Thursday. This will push a cold front into the Ohio Valley Thursday night into Friday, bringing our next chance of appreciable precipitation. Given it's day 7, there is some model discrepancy in the timing of the front and the arrival of colder air in its wake. For now, will advertise precipitation of the liquid variety as temperatures remain slightly above normal.

Marine
Gusty northerly winds continue over the waters, especially for the middle Chesapeake Bay and lower Tidal Potomac River. A Gale Warning remains in effect through Sunday south of Drum Point along the Bay and south of Cobb Island along the Potomac River. An SCA (Small Craft Advisory) remains in effect for the rest of the waters during this time, but it will be marginal for tonight over the upper Tidal Potomac.

Small Craft Advisories will likely need to be extended into Monday morning on the Chesapeake Bay. Winds begin to taper off Monday afternoon.

Sub SCA (Small Craft Advisory) conditions expected Tuesday and Tuesday night as winds remain at 15 knots or less. Gradient increases on Wednesday as we reside between exiting low pressure well to our northeast and building high pressure to the south. Thus SCA (Small Craft Advisory) conditions will be possible over the waters Wednesday and Wednesday evening.

Tides / Coastal Flooding
Complex tidal forecast over the next few days with coastal low moving slowly off the coast, as north/northeast winds try to push water southward while the tidal surge with the low pushes excess water into the Bay. This is already on display this evening, with water closer to near normal on the northern Bay, and two feet above normal at Norfolk. At the moment, the opportunity for flooding looks minimal until at least the third high tide cycle, so no advisories at this time. On Monday, there may be a "snap- back" as winds lighten and excess water on the southern Bay is allowed to surge northward. Don't have the confidence for moderate thresholds to be reached to issue any Coastal Flood Watches yet.

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None.
MARINE...
Small Craft Advisory until 6pm EST Sunday for ANZ530>533-535- 536-538>542. Gale Warning until 6pm EST Sunday for ANZ534-537-543.