Marine Weather Net

Patuxent River to Broomes Island MD Marine Forecast


THIS AFTERNOON

E
WINDS
5 KNOTS

TONIGHT

S
WINDS
5 KNOTS

WED

NE
WINDS
5 KNOTS

WED NIGHT

SE
WINDS
5 KNOTS

The Marine Weather Forecast In Detail:
ANZ542 Forecast Issued: 137 PM EDT Tue Jul 27 2021

This Afternoon...E Winds 5 Kt. Waves Less Than 1 Ft. Isolated Showers.
Tonight...S Winds 5 Kt. Waves Less Than 1 Ft.
Wed...Ne Winds 5 Kt. Waves Less Than 1 Ft. A Chance Of Showers And Tstms.
Wed Night...Se Winds 5 Kt. Waves Less Than 1 Ft. A Chance Of Showers And Tstms.
Thu...Se Winds 5 To 10 Kt. Waves 1 Ft.
Thu Night...Sw Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Showers And Tstms.
Fri...N Winds 5 To 10 Kt. Waves 1 Ft.
Sat...Nw Winds 5 To 10 Kt...Becoming S. Waves 1 Ft. 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
219pm EDT Tuesday July 27 2021

Synopsis
A weak frontal zone will remain draped near or over the Middle Atlantic through Wednesday, reinforced by disturbances aloft. A stronger cold front will cross the region Thursday into Friday. High pressure will follow for the first half of the weekend before another frontal boundary approaches by early next week.

Near Term - Through Tonight
A weak frontal boundary has dropped south of the region as of early this afternoon. There are hints of a weak surface trough over central Virginia (near the Blue Ridge Mountains), with river/bay breeze circulations in the vicinity of southern Maryland. These two areas will be the foci for any isolated convective (shower/thunderstorm) activity this afternoon into this evening. Steepening lapse rates in the lower levels and moderate CAPE may result in a spotty wind gust or two, but overall the potential for strong to severe thunderstorms is pretty low (as is the probability of thunderstorms overall at any one point). Any such activity should wane this evening with the loss of daytime heating.

Patchy fog is possible in outlying areas overnight, though the lower levels are expected to be drier than last night which should keep any fog from getting too dense. Otherwise, a mainly clear night is anticipated with low temperatures near to slightly above normal for late July.

Short Term - Wednesday Through Thursday Night
A shortwave trough currently over Saskatchewan in Canada is expected to cross the region Wednesday afternoon. This should enhance the pre-existing frontal zone/lee trough (possibly merging with another weak front/surface reflection). Lift from these features will act on the instability present to result in scattered afternoon and evening showers and thunderstorms. Modest flow aloft may lead to some loose organization, perhaps resulting in a focused cluster/corridor or two of gusty to damaging winds, but certainty in specifics is low a day in advance given the overall marginal environment for organization. Notably, the 12z HRRR (High-Resolution Rapid Refresh) mixes dew points to around 50 during the afternoon, whereas as the NAMNest holds dew points in the mid 60s (as does most other guidance). This plays a big role in available CAPE and subsequent depth of convection. Regardless, very steep lapse rates in the lower levels and ample DCAPE should result in an environment favorable for strong downdrafts/bursts in the stronger cells.

A much more potent (convectively augmented) shortwave trough and accompanying mid-level speed max are expected to pivot across the area Thursday afternoon. There are uncertainties in the extent of upstream convection and clouds which may temper instability, though the 12z guidance overall has trended higher with projected instability/CAPE. The seasonably strong trough and wind field with moderate to strong CAPE may result in one or more clusters of organized thunderstorms (perhaps initiating as more discrete cells for a time) capable of damaging wind and hail, heavy rain/flooding given high humidity, and even a tornado threat. The extent of severe weather will be highly dependent on the evolution of upstream convection over the next 48 hours as well as the magnitude of instability locally. Overall, the threat is marginal at this time due to low confidence, but with a high ceiling; a worst case scenario would be one where widespread gusty to damaging winds are observed due to the favorable background environment.

Temperatures should run a little above normal Wednesday through Thursday before heat and humidity take a tumble behind the front by the end of the week.

Long Term - Friday Through Tuesday
A few isolated showers are possible across our southern zones and bay waters both Friday afternoon and again Saturday evening with a weak boundary nearby. Otherwise, the weekend looks slightly cooler by a couple of degrees compared to previous days with highs in the middle to upper 80s. The warmer day appears to be Friday.

Later Sunday into Monday would be the next better chance of showers and thunderstorms as a cold front pushes in from the northwest and nearly stalls to the south by later in the day Monday. High temperatures will approach 90 ahead of the front but could be held in the middle to upper 80s in any cloud cover and convection.

Marine
Through early Thursday, wind outside of convection should stay under SCA (Small Craft Advisory) levels. There is some increase in southwesterly winds expected on Thursday which may require a SCA (Small Craft Advisory) for portions of the waters. In terms of thunderstorms, some of the lower marine zones may see a thunderstorm this afternoon and evening, but confidence is low. A better chance for thunderstorms exists on Wednesday and Thursday, with Special Marine Warnings possible.

A Small Craft Advisory is possible Friday. Winds northwest 10 to 20 knots w/ higher gusts Friday. Winds diminishing northwest 5 to 10 knots Friday night and Saturday, becoming south 5 to 10 knots Saturday night.

Tides / Coastal Flooding
Tides are running a little above normal, but should stay mainly below minor flooding thresholds the next couple days. A cold front with NW flow behind it should force water levels down Thursday night into Friday.

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