Tidal Potomac from Key Bridge to Indian Head MD Marine Forecast
|Rest Of Today...Ne Winds 5 To 10 Kt. Waves 1 Ft. A Slight Chance Of Rain Late This Morning, Then Occasional Rain This Afternoon.|
|Tonight...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 1 Ft. Occasional Rain Or Drizzle Likely.|
|Tue...N Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 1 Ft.|
|Tue Night...N Winds 5 To 10 Kt. Waves 1 Ft.|
|Wed...Ne Winds 5 Kt. Waves Less Than 1 Ft.|
|Wed Night...S Winds Around 5 Kt. Waves 1 Ft.|
|Thu...S Winds 5 To 10 Kt. Waves 1 Ft.|
|Fri...S Winds 5 Kt. Waves Less Than 1 Ft.|
|Area Forecast Discussion|
National Weather Service Baltimore MD/Washington DC
1005am EDT Monday Mar 25 2019
Synopsis: A low pressure system will track across the area today, bringing a cold front southward by this evening. High pressure will settle south from the Great Lakes on Tuesday and remain in control of the weather through the end of the week.
Near Term - Through Tonight
Some spotty light rain has developed over eastern West Virginia and western Maryland this morning, and this will continue to spread eastward through the day. Formidable breaks in the clouds east of the Blue Ridge mountains are expected to quickly fill in by midday.
There are two primary forcing features today. The first will be a band of mid level frontogenesis which spreads eastward near the Mason-Dixon line during the midday hours. Then a surface low will slide across the Virginia-North Carolina border late this afternoon and early evening, with the mid level vort max diving similarly to the southeast. In between (including the Washington metro area), rain may be more at a minimum. Have kept categorical Probability of Precipitation for much of the area, though it may be more of a "high PoP-low Quantitative Precipitation Forecast" event for some, and have thus worded the forecast as "occasional rain." In any event, amounts should not be much above a third of an inch even where there is a steadier rain. Given the slower onset of any meaningful rain across much of the area and slower progression of cold advection, guidance now suggests areas from DC to the south have a good chance at reaching 60 today.
There is some model disagreement on how quickly drier air infiltrates the area tonight. Have leaned forecast toward HREF progression, although this is admittedly on the slower end of the spectrum. This does allow some of the higher elevations above 2000 feet to briefly change over to snow before precipitation ends, but there should be little to no accumulation. Patchy drizzle is possible for a time as well this evening as moisture becomes more shallow. Otherwise, clearing should gradually commence from the north with gusty north winds. Low temperatures will eventually reach the upper 20s and lower 30s
Short Term - Tuesday Through Wednesday Night
High pressure of Canadian origin will be building southward from the Great Lakes on Tuesday. Northerly winds and cold air advection will keep a cap on temperatures despite mainly sunny skies. Highs will only be in the 40s to around 50.
The high will continue to build southward through the middle of the week and elongate into a NE-SW fashion as systems move off the Florida coast and north of the Canadian border. This will spell dry but seasonably cool weather. While temperatures will moderate some during the day on Wednesday, both Tuesday and Wednesday nigheights will see lows near or below freezing for much of the area
Long Term - Thursday Through Sunday
The end of this week and into the first half of next weekend will feature largely dry and warming conditions as heigheights build across the region.
The surface high that will be present over the region for the middle of the week will shift southeastward and offshore by Thursday. At the same time a weak low pressure system will pass well north of the region into southern Canada, but will initially lead to increased warm air advection over the region before sending a cold front into the eastern Great Lakes. The vast majority of the region is expected to remain dry, but a stray shower is possible in northern/western areas.
The high will remain positioned offshore of the eastern US on Friday as a developing low pressure system ejects northeastward from the central Plains and towards the Great Lakes. This will send the front likely positioned near the eastern Great Lakes back northward, again increasing warm air advection over the region. Similar to Thursday, the vast majority of the region should remain dry, but a stray shower is again possible.
By Saturday the area of low pressure will move northeastward through the Great Lakes, further increasing the southerly flow along the eastern seaboard. Dry conditions likely to continue.
All of this spells out largely dry weather Thursday through Saturday with temperatures continuing to tick up each day and Saturday likely seeing the warmest temperatures. Highs Thursday in the low 60s should warm to near 70F Friday, and then likely well into the 70s Saturday.
The cold frontal system will then cross the region Sunday with chances for showers.
A warm front will stall across the waters today with an area of low pressure tracking eastward along it to near Norfolk by this evening. Winds should be fairly light in weak gradient through the day, but as a pressure surge arrives from the north this afternoon, northerly winds will begin increasing. Have started a Small Craft Advisory for all waters at 6 PM, although some areas may not consistently mix these winds down. As the low strengthens off the coast tonight, the strongest north winds will develop, especially on the Bay where they could reach 30 kt.
Expecting winds to gradually subside through Tuesday as high pressure builds in from the north, though the Small Craft Advisory will continue for a good part of the day. Then sub-Small Craft Advisory conditions are expected Wednesday through Friday with high pressure in place
NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None.
Small Craft Advisory from 6pm this evening to 2pm EDT Tuesday for ANZ530-531-535-536-538-539.
Small Craft Advisory from 6pm this evening to 6pm EDT Tuesday for ANZ532>534-537-540>543