Buckle up for a busy night, Maryland. NWS Baltimore/Washington (4:26 PM update) and NWS Mount Holly (3:54 PM update) both have their eyes on a line of storms punching in from the Alleghenies, with a second wave possibly forming behind it. A Severe Thunderstorm Watch covers essentially the entire state west of the Bay, and a Severe Thunderstorm Warning is already tagging Allegany County as of this writing. Damaging wind gusts are the headline threat, a tornado or two can’t be ruled out, and there’s a real flash flooding risk given how saturated the atmosphere is aloft. This wraps up by the pre-dawn hours, but it won’t feel short while it’s happening.
Tonight’s Timeline
- Now – 6 PM: A Severe Thunderstorm Warning is active for Allegany County as the first line crosses from West Virginia. Damaging wind gusts are the main concern here.
- 6 – 9 PM: The line pushes into Washington, Frederick, Garrett, and Carroll counties. Expect gusty, potentially damaging winds, torrential rain, frequent lightning, and an isolated tornado can’t be ruled out, especially near the warm front draped roughly Frederick-to-Fredericksburg.
- 8 – 10 PM: Storms reach the I-95 corridor — Baltimore, Howard, Anne Arundel, DC suburbs. This is when the core threat arrives for the metro.
- 10 PM – 1 AM: A second cluster of storms, currently organizing over Ohio/Indiana, may follow a couple hours behind the first, with some risk of backbuilding/training storms parked over the same areas — particularly the DC Metro — which is exactly the recipe for flash flooding.
- Overnight into 2–3 AM: Storms push into Southern Maryland and the Eastern Shore before weakening and clearing the area, with drier conditions settling in toward daybreak.
Region by Region
Western Maryland
Garrett County (Deep Creek/Oakland): Overnight low near 65°. Widespread showers and thunderstorms are ongoing with 100% coverage tonight — this is the county already under a Flood Watch following a flood event just days ago, so any additional heavy rain is a real concern. Winds west 7-10 mph.
Allegany (Cumberland): Low around 71°. A Severe Thunderstorm Warning is in effect right now, with the threat continuing as more rounds arrive; 100% chance of widespread storms tonight, transitioning to scattered activity later. Damaging wind gusts are the top concern.
Northern & Central Maryland
Washington County (Hagerstown): Low near 71°, 97% chance of widespread storms tonight as the line crosses directly overhead this evening. Damaging wind gusts and heavy downpours are likely.
Frederick County: Low around 71°, 93% storm chance — sits right along that warm front, which raises the local tornado and training-storm risk.
Carroll County: Similar setup to Frederick, under the same Severe Thunderstorm Watch, with storms arriving through the evening hours.
Baltimore Metro
Baltimore City & County, Harford, Howard, Anne Arundel: Low around 74°, 91% chance of showers and thunderstorms tonight, arriving mainly between 8-10 PM and continuing into the overnight as additional rounds push through. Winds south 3-10 mph ahead of the line, gusting higher in any storm. Anne Arundel also carries a Coastal Flood Advisory for minor tidal flooding — keep that in mind if you’re near the water’s edge along the Bay tonight.
DC Suburbs
Montgomery & Prince George’s counties: Low near 70-71°, 87% chance of storms, with coverage increasing from scattered to widespread as the evening progresses. Both counties are also now under a targeted Flood Watch for the DC Metro given the extreme moisture in place — precipitable water values are running near 2 to 2.5 inches, which is about as juicy as it gets. Training storms are a real risk here.
Southern Maryland
Charles County: Under the same DC Metro Flood Watch — low around 72°, 82% chance of storms, arriving mainly later this evening into early tonight.
Calvert & St. Mary’s: Low near 72°, chance of showers and thunderstorms increasing to 82% overnight as the line sweeps southeast. Gusty winds south 7-13 mph ahead of storms.
Upper Eastern Shore
Cecil, Kent, Queen Anne’s, Talbot, Caroline: Low around 71°, 89% chance of showers and storms overnight as the line finally reaches the Shore later than the western counties — activity should be arriving after 10 PM and continuing into the pre-dawn hours before tapering.
Lower Eastern Shore
Dorchester, Wicomico, Somerset: Low near 72°, 72% chance of storms overnight, generally the last part of the state to see activity as it weakens while pushing east of the warm front.
Ocean City & the Coast
Worcester County/Ocean City: Low around 73°, 69% chance of showers and thunderstorms overnight, with breezy south winds 13-17 mph ahead of the activity. At the beach: surf around 2 to 3 feet, rip current risk low for Monday, water temps in the upper 70s. Heads up for swimmers — jellyfish are being reported in large numbers nearshore. High tide at the Ocean City Fishing Pier is 11:37 AM Monday.
Active Hazards
- Severe Thunderstorm Warning: Allegany County, MD (also parts of VA/WV) — damaging winds are the primary threat with the initial storm cell.
- Severe Thunderstorm Watch #588: Covers Allegany, Carroll, Charles, Frederick, Garrett, Howard, Montgomery, Prince George’s, Washington counties plus DC and a wide swath of VA/WV, in effect through tonight. Damaging winds and an isolated tornado are the concerns.
- Flood Watch — Garrett County (Western & Eastern): In effect tonight given saturated ground from a recent flood event and another round of heavy rain on the way.
- Flood Watch — DC Metro: Newly issued for DC, Prince George’s, Charles, and Central/Southeast Montgomery counties (plus neighboring VA jurisdictions), in effect tonight for potential flash flooding from training storms.
- Coastal Flood Advisory: Anne Arundel County — minor tidal flooding possible, especially around high tide.
Severe Weather & Flooding Detail
This is a legitimate multi-hazard setup. MLCAPE is forecast to build to 1500-2000 J/kg ahead of the line with effective bulk shear of 30-35 knots — plenty to support organized damaging wind gusts, and with roughly 30 knots of low-level shear oriented across the line, a brief spin-up tornado is possible, especially where the line interacts with the warm front near Frederick. Separately, the flash flood threat is arguably the bigger overall concern: precipitable water values are approaching 2 to 2.5 inches, which combined with deep warm cloud layers means any storm can produce very heavy rain rates. If a second round trails the first with any backbuilding or training — which some guidance supports, especially near DC — localized flash flooding becomes a serious possibility. Confidence is high on strong-to-severe storms occurring; confidence is more moderate on exactly where the heaviest, most repetitive rainfall sets up. Storms should clear the area and taper off by 2-3 AM.
Heat, Wind & the Bay
Humidity remains thick and tropical-feeling ahead of the front, though temperatures tonight are seasonable rather than oppressive. Winds will gust higher within any thunderstorm cell — that’s where the damaging wind threat lives. On the water, mariners on the Chesapeake Bay and tidal Potomac should expect a rough few hours wherever storms pass overhead tonight, with sudden wind shifts and reduced visibility in downpours; it’s a good night to have already tied up.
Overnight Lows by Zone
| Zone | Low |
| Western Mountains (Garrett) | Around 65° |
| Cumberland/Hagerstown | Low-to-mid 70s (71°) |
| Frederick/Carroll | Around 71° |
| Baltimore/DC Corridor | Low-to-mid 70s (70-74°) |
| Southern Maryland | Around 72° |
| Eastern Shore | Low-to-mid 70s (71-72°) |
| Ocean City | Around 73° |
Looking Ahead
Monday brings a much drier, sunnier start statewide, with highs building into the upper 80s to near 90° across central Maryland (88-90° around Baltimore, DC suburbs, and Southern Maryland) and mid-80s toward the mountains and Shore. There’s still a chance of afternoon showers and thunderstorms Monday, especially west of I-95, but coverage and severe potential drop off sharply compared to tonight. Tuesday looks like the pick of the week — sunny, comfortable, and notably lower humidity behind this system, with highs mostly in the mid-to-upper 80s. Attention then turns to Wednesday night into Thursday, when the next cold front approaches and could bring another round of showers and storms, with some uncertainty on whether it stalls nearby into the weekend.
Data: NWS Baltimore/Washington, Mount Holly & Wakefield.
Stay dry and stay weather-aware tonight, Maryland — MD Weather Alerts will keep watching the radar so you don’t have to.