Marine Weather Net

Baltimore Harbor & Patapsco River Marine Forecast









The Marine Weather Forecast In Detail:
ANZ538 Forecast Issued: 1243 AM EST Fri Feb 26 2021

Overnight...Nw Winds 5 Kt. Waves Flat.
Fri...E Winds 5 Kt. Waves Flat.
Fri Night...Se Winds 5 Kt. Waves Less Than 1 Ft. Rain. Vsby 1 To 3 Nm.
Sat...S Winds 5 Kt. Waves Less Than 1 Ft. Rain.
Sat Night...Ne Winds Around 5 Kt. Waves Flat. A Chance Of Rain.
Sun...Se Winds 5 Kt. Waves Less Than 1 Ft. Showers.
Sun Night...W Winds Around 5 Kt. Waves Flat. Showers Likely.
Mon...Nw Winds 10 To 15 Kt. Waves 1 Ft. Showers Likely In The Morning.
Tue...Nw Winds 5 To 10 Kt...Becoming S. Waves 1 Ft. A Chance Of Showers In The Evening. A Chance Of Rain And Snow Showers After Midnight.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
849pm EST Thu Feb 25 2021

High pressure builds into our region through Friday. Multiple low pressure systems will impact our region this weekend. High pressure is forecast to return by the middle parts of next week.

Near Term - Through Friday
High pressure will continue to build toward the area tonight from the north. However, and upper-level disturbance (jetmax) in the zonal flow will pass through overnight, and this will cause high and mid-level clouds to increase. Lows tonight will range from the 20s in the mountains and colder valleys/rural areas to the lower and middle 30s for most other locations.

The high and mid-level clouds may give way to a period of sunshine Friday morning, but as high pressure moves offshore clouds will increase Friday afternoon. The increasing clouds will limit heating, so highs will be generally in the 40s for most places (30s in the mountains).

Low pressure will begin to track from the Gulf Coast States toward the Tennessee Valley, and southern stream moisture will advect well out ahead of this system, overrunning the low-level colder air in place. This will cause precipitation to break out later Friday afternoon in our southwestern zones. Despite a lack of cold air, there will be plenty of dry air ahead of this system. Therefore, insitu cold air damming is likely as precipitation evaporates at the onset of the event. Air will be cold enough for snow in the higher elevations, but temps will likely remain above freezing in the valleys Friday afternoon. Therefore, rain or a rain/snow mix is more likely in the valleys with mainly snow in the higher elevations.

Short Term - Friday Night Through Saturday Night
A multi-low frontal system will approach our region from the south Friday evening and into Saturday. Precipitation will continue to overspread the area from southwest to northeast Friday evening due to overrunning. Cold air wedged into central Virginia Friday evening will combine with encroaching precipitation from the south to produce areas of wintry mix down in parts of central Virginia and the Shenadoah Valley. Models are indicating a warm layer aloft which suggest that freezing rain and sleet could mix in with snow as precipitation initially moves into the southern parts of our region (mainly across the higher elevations). There has been a slight cooling trend aloft which suggests more snow/sleet vs freezing rain but the time to transition from snow to rain seems to have shortened. A Winter Weather Advisory is in effect for portions of the Potomac Highlands, central Shenandoah Valley, and the Blue Ridge Mountains. Accumulating snow and ice is expected across these areas, and this is where confidence is highest because precipitation will be heavier down across these areas and it will overspread these areas quicker before the warmer air works in. Farther northeast, accumulating snow and ice is possible Friday night, especially in the higher elevations so the Winter Weather Advisory may need to be expanded in area.

Precipitation should transition to all rain after daybreak on Saturday as the main system shifts northward into our region. I expect all of our forecast area to be experiencing precipitation by 12Z on Saturday. Periods of light to moderate rain should continue into the early parts of Saturday but the first round of precipitation should taper sometime Saturday evening. Temperatures will warm up into the mid to upper 50s on Saturday with mild lows in the upper 30s to 40s Saturday evening.

Another frontal system will move into our region from the west early Sunday morning. This system will have the potential to bring an extended period of moderate rain to our region through Sunday. As the snow pack along the Allegheny front has around 3 to 5 inches of liquid, the combination of warm moderate rain along with a deep snow pack could lead to a flood threat on Sunday.

Long Term - Sunday Through Thursday
Multiple periods of rain are expected on Sunday as a wave of low pressure moves along a stationary front. During the past 24 hrs, model guidance have trended farther north with the position of this front, and thus, with the axis of heaviest rainfall. Rainfall amounts of half to an inch of rain are most likely with reasonable highest scenarios of one to two inches possible. Even these higher amounts would not cause any flooding issues due to stratiform nature of precipitation and rapidly shrinking snow pack in the mtns. Surface front shifts south Monday with drying expected through the middle of next week.

Cooler conditions, but still near or above normal temperatures are expected next week under high pressure.

SUBSCA (Small Craft Advisory) conditions expected through Friday. A low pressure system will impact the waters late Friday through this weekend bringing the next chance for SCA (Small Craft Advisory) conditions.

Marginal SCA (Small Craft Advisory) conditions possible on Sunday if any.

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...Winter Weather Advisory from 3pm Friday to 6am EST Saturday for VAZ025-026-503-504-507-508. WV...Winter Weather Advisory from 3pm Friday to 6am EST Saturday for WVZ505-506. MARINE...None.