MD Weather Alerts

EVENING / OVERNIGHT EDITION · Tuesday, August 18, 2026

Good evening, Maryland. Tonight is about as low-drama as it gets — the weak cold front that sparked a few isolated afternoon showers and rumbles (mainly south and east of I-95, per both NWS Baltimore/Washington’s 3:13 PM update and NWS Mount Holly’s 5:37 PM discussion) is sagging south and losing its energy with the sun. High pressure builds in behind it, so most of us are looking at clearing skies, dropping humidity, and a genuinely pleasant night. The one thing worth watching: patchy fog developing in spots, especially river valleys and southeastern areas that caught rain this afternoon.

Tonight’s Timeline

• 6–9 PM: Any lingering isolated showers/storms (mainly Southern Maryland and the Eastern Shore) fizzle out with the loss of daytime heating.
• 9 PM–Midnight: Skies clear out west first (Garrett, Allegany, Washington) as high pressure noses in; central and southern MD lag behind with more cloud cover overnight.
• Midnight–5 AM: Calm, light winds. Patchy fog forms in river valleys west of the Blue Ridge (Potomac Highlands) and in spots south/east of I-95 where rain fell today.
• Early Wednesday: Fog burns off with sunrise; a sunny, warmer day builds in behind tonight’s calm.

Western Maryland

Garrett County (Deep Creek / Oakland): Lows around 55° — comfortably cool mountain air, maybe even a light-jacket night on the deck. Winds light out of the west, 0-6 mph. Mostly clear skies with patchy fog possible in the valleys toward dawn. Precip chance essentially nil at 1%.

Allegany County (Cumberland): Low near 59°, mostly clear, calm winds (northwest 0-6 mph). A comfortable, quiet night with no rain in the picture (0% chance).

Northern & Central Maryland

Washington County (Hagerstown): Low around 62°, mostly clear, light north winds under 6 mph. Zero rain chance tonight — a genuinely crisp, dry night after a mostly sunny afternoon near 83°.

Frederick & Carroll Counties: Low near 64°, mostly clear skies, winds light out of the northwest (0-3 mph). No precipitation expected — a great night to leave the windows cracked.

Baltimore Metro

Baltimore City & County, Harford, Howard, Anne Arundel: Low around 70°, mostly clear with just a slight (8%) chance of a stray shower well after dark before things dry out. Winds light and variable from the northwest, 1-6 mph. Comfortable enough for a late walk around the Inner Harbor or a porch sit in Bel Air — humidity easing back a notch from today.

DC Suburbs

Montgomery & Prince George’s Counties: Low near 68°, mostly clear with essentially no rain chance (1%). Light northwest winds. A quiet, mild night across the Beltway corridor.

Southern Maryland

Charles, Calvert, St. Mary’s Counties: Low around 69°, with an isolated shower possible right at the start of the evening (16% chance) before skies turn mostly clear overnight. Light north winds around 3 mph. Any lingering afternoon storminess should be well out of here by the time most folks turn in.

Upper Eastern Shore

Cecil, Kent, Queen Anne’s, Talbot, Caroline Counties: Low near 71°, partly cloudy early with patchy fog developing overnight — keep that in mind for early commutes across the Bay Bridge corridor tomorrow. Light west winds under 5 mph. Rain chance a modest 10%.

Lower Eastern Shore

Dorchester, Wicomico, Somerset Counties: Low around 71°, with a lingering chance of showers/storms (29%) early in the evening before patchy fog takes over overnight. Light southeast winds, 1-6 mph. This is the corner of the state most likely to see a stray rumble tonight before things settle.

Ocean City & the Coast

Worcester County: Low near 73°, with a slight chance of showers/storms (18%) early tonight, then patchy fog developing as winds go light out of the south (2-7 mph). Surf running around 2 feet with a low rip current risk — a calm night at the beach. Water temps in the upper 70s. Tomorrow’s tide at the Ocean City Fishing Pier: low around 6:53 AM, high around 1:16 PM.

Active Hazards

None. There are no active watches, warnings, or advisories for Maryland at this time, and NWS Baltimore/Washington’s outlook confirms no hazardous weather is expected overnight into Wednesday. Enjoy the break.

Severe & Flooding

No severe weather or flooding concerns tonight. The isolated storms that popped this afternoon were sub-severe and are fading with sunset. The next real chance for stronger storms doesn’t arrive until Thursday, when a cold front works through — more on that below.

Fog, Winds & Bay/Marine

Patchy fog is the main overnight nuisance, favoring river valleys in the mountains and southeastern Maryland where today’s showers left the air extra moist. Give yourself a few extra minutes on the roads at first light if you’re in those spots. Winds are light across the board — mostly under 8 mph from the northwest — with no marine hazards noted for the Chesapeake Bay, tidal Potomac, or coastal waters tonight.

Overnight Lows by Zone

Zone	Low Temp
Western Mountains (Garrett)	~55°
Cumberland/Hagerstown	59–62°
Frederick/Carroll	~64°
Baltimore/DC Corridor	68–70°
Southern Maryland	~69°
Eastern Shore	71–72°
Ocean City	~73°

Looking Ahead

Wednesday is the pick of the week — sunny, warm, and dry statewide, with highs from the upper 70s in Garrett County up to near 89° in Baltimore and the DC suburbs. Enjoy it, because Thursday brings a stronger cold front through the state with showers and thunderstorms likely, some possibly strong, especially toward southern Maryland where NWS Mount Holly and Wakefield both flag a marginal severe risk. Unsettled weather then lingers into the weekend before a cooler, drier pattern takes hold early next week.

Data: NWS Baltimore/Washington, Mount Holly & Wakefield.
MDWA — your neighbors watching the sky so you don’t have to. Sleep easy, Maryland. See you tomorrow.