Tidal Potomac from Indian Head to Cobb Island MD Marine Forecast
|Today...Ne Winds 5 Kt. Waves Less Than 1 Ft.|
|Tonight...E Winds 5 Kt. Waves Less Than 1 Ft.|
|Mon...E Winds 5 To 10 Kt. Waves 1 Ft.|
|Mon Night...E Winds 5 To 10 Kt. Waves 1 Ft.|
|Tue...E Winds 5 To 10 Kt. Waves 1 Ft.|
|Tue Night...Se Winds 5 To 10 Kt. Waves 1 Ft.|
|Wed...Se Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Showers In The Morning, Then Showers Likely.|
|Thu...E Winds 5 To 10 Kt...Becoming Nw. Waves 1 Ft. A Chance Of Showers.|
| Area Forecast Discussion|
...UPDATED National Weather Service Baltimore MD/Washington DC
1009am EDT Sunday September 19 2021
High pressure will settle over New England today. Mostly dry and seasonable weather is slated through Tuesday. A strong cold front will pass through the area later Wednesday into Thursday and Canadian high pressure will build overhead late next week.
Near Term - Until 6pm This Evening
Fair weather expected today as subsidence inversion continues to strengthen per 12Z IAD sounding. Temperatures will be cooler today under a northerly flow behind a cdfnt that moved through the area last night.
Previous afd... Rex blocking over the central US continues as upper level ridging gradually shifts eastward over the next few days. Surface high pressure to our north will shift over New England today, resulting in a weak cold front dropping southward. Dry conditions are expected today, aside from the slight chance for an isolated shower over the southern Potomac Highlands and the Central Shenandoah Valley as moisture advection over the Gulf states tries to nudge northward. However, given the influence from the high, thinking it should remain mostly dry. Otherwise, expect mostly sunny skies with temperatures in the upper 70s to low 80s across the region.
Short Term - 6pm This Evening Through Tuesday
Upper level ridge will crest over the Mid Atlantic region by early Monday morning as surface high pressure develops offshore; inducing an easterly flow. The high will reside offshore through Tuesday as mostly dry and seasonable weather is expected to continue during this time. As an upper level trough approaches from the west, cloud cover will increase late Tuesday as well as an increased chance for showers Tuesday night into Wednesday.
Long Term - Tuesday Night Through Saturday
For Wednesday, the aforementioned upper level trough will sharpen and become negatively tilted before eventually cutting off over the Ohio Valley into Thursday. A strong cold front associated with this system will push through late Wednesday into Thursday bringing rain to the entire region. Thinking the threat for severe weather is still low at this time, as instability still seems to be lacking. Even with a lot of shear present, still have to at least have a little bit of instability to work with, and no guidance is showing that at this time.
For Thursday night, expecting the rain to be gone and for skies to clear out with much cooler temperatures. Lows will reach the mid to upper 50s along/east of I-95, then the 40s to low 50s further west. May even see the potential for some frost across the Allegheny Front.
Friday through the weekend will be cooler, with highs in the low to mid 70s each day. The primary upper-low will try to spin through the region towards the end of the period, which could bring some showers and continued cooler temperatures.
Northerly channeling is expected today with SCA (Small Craft Advisory) conditions likely over the Chesapeake Bay. Winds relax this afternoon, but marginal SCA (Small Craft Advisory) conditions could persist over the southern waters through early next week.
For Wednesday into Thursday, marine hazards are expected sometime during the period as a cold front passes over the waters. Gale conditions will be possible Thursday.
Tides / Coastal Flooding
Anomalies have dropped on northerly winds, but developing onshore flow early in the week may cause new water level rises. Minor coastal flooding will be possible middle of the week under strengthening southerly flow before strong frontal passage early Thu.
NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None.
Small Craft Advisory until 11am EDT this morning for ANZ531>534-539>541-543.