Good evening. NWS Baltimore/Washington (5:16 PM update) and NWS Mount Holly (4:37 PM update) both have Maryland locked into another round of showers and thunderstorms tonight, with a Severe Thunderstorm Watch already posted for Garrett and Allegany counties. A complex of storms is sliding down out of the Ohio Valley and Great Lakes and will work its way into the state through the evening and overnight hours, riding on top of thick, tropical humidity that’s kept heat advisories in place across the Eastern Shore. Friday brings more of the same — hot, sticky, and stormy — before a much nicer, drier Labor Day weekend finally arrives.
Timing Tonight
- Now–9 PM: Severe storms possible over Garrett and Allegany counties as the watch area storms sag south and east from the Pittsburgh/Erie/Cleveland clusters. Damaging wind gusts and large hail are the main threats.
- 9 PM–Midnight: The organized complex (or a broken line, depending on how it evolves) pushes into Washington, Frederick, and Carroll counties. A track along or south of I-70 looks most favored for any surviving punch.
- Midnight–4 AM: Activity, likely weakening as it loses daytime heating, works into the Baltimore/DC corridor and central Maryland. Isolated strong storm potential lingers, especially near the Potomac/US-50 corridor where a lingering moisture boundary sits.
- 4 AM–Sunrise: Showers and a few lingering storms spread onto the Eastern Shore and toward the Bay, with activity trending more scattered and less organized by daybreak. Patchy fog possible where rain has soaked the ground, especially in the Cumberland Valley.
Region by Region
Western Maryland
Garrett (Deep Creek/Oakland): Low near 65°, wind light out of the west. Scattered showers and storms continue this evening (58% chance), with this county sitting inside the Severe T-Storm Watch — damaging gusts and hail are possible before storms taper after midnight. Mountain campers should have a plan for shelter.
Allegany (Cumberland): Low near 71°, muggy. Also under the Severe Watch, with a 75% chance of showers/storms continuing into the night, some possibly strong. Any storm here could pack a punch with the surface still warm from a 92° afternoon.
Northern & Central Maryland
Washington County (Hagerstown): Low near 72°, 70% chance of storms overnight as the complex arrives from the west — could be locally strong.
Frederick & Carroll: Low near 72°, scattered storms likely overnight (54% chance) as activity works through mid-evening into midnight. Watch for gusty outflow winds ahead of any line.
Baltimore Metro
Baltimore City & County, Harford, Howard, Anne Arundel: Low near 76°, still sticky. A 56% chance of storms redevelops overnight as the complex arrives — timing favors after 10 PM into the early morning hours. Any storm reaching the metro tonight would still be capable of gusty winds given lingering instability, though confidence in a widespread severe hit through the corridor is lower than farther west.
DC Suburbs
Montgomery & Prince George’s: Low near 74°, scattered storm chances (43%) overnight, mainly before dawn. Muggy and unsettled — keep the windows shut if you’re hoping for a breeze; the dew points won’t give you one.
Southern Maryland
Charles, Calvert, St. Mary’s: Low near 74°, isolated storms this evening transitioning to scattered activity overnight (39% chance). The Chesapeake and tidal Potomac remain worth watching for any gusty storm outflow — small craft should keep an eye on radar if out after dark.
Upper Eastern Shore
Cecil, Kent, Queen Anne’s, Talbot, Caroline: Low near 74°, chance of storms overnight (49%) as activity spreads east after midnight. A Heat Advisory is posted for Kent, Queen Anne’s, Talbot, and Caroline — dew points in the mid-to-upper 70s keep the air feeling oppressive even after sunset.
Lower Eastern Shore
Dorchester, Wicomico, Somerset: Low near 75°, chance of storms overnight (43%), arriving toward the pre-dawn hours. Heat Advisory remains in effect here too, and a Coastal Flood Statement is posted — minor tidal flooding is possible in the usual low-lying spots (Crisfield, Cambridge waterfront) around the high tide cycle.
Ocean City & the Coast
Worcester: Low near 75°, a slight chance of a shower or storm overnight (39%) mainly late. Surf around 2 feet with a Low rip current risk for Friday. Low tide at the Ocean City Fishing Pier is 7:21 AM Friday, high at 1:52 PM. Inland Worcester is also included in tonight’s Heat Advisory, so even beach-adjacent communities away from the immediate shoreline should expect the muggy air to stick around after dark.
Active Hazards
- Severe Thunderstorm Watch — Allegany and Garrett counties (also Grant, Hampshire, Hardy, Mineral counties in WV), in effect into the overnight hours. Damaging wind gusts and large hail are the primary threats as clusters of storms move in from the Ohio Valley/Great Lakes.
- Heat Advisory — Kent, Queen Anne’s, Talbot, and Caroline counties. Heat index values reaching the upper 90s to around 100° with high humidity.
- Heat Advisory — Dorchester, Wicomico, Somerset, and inland Worcester counties, with similarly steamy heat index readings.
- Coastal Flood Statement — Dorchester, Wicomico, and Somerset counties. Minor tidal flooding possible in low-lying, flood-prone areas near the Bay and tidal rivers.
Severe & Flooding Threat
The severe threat tonight hinges on how organized the incoming Mesoscale Convective Complex becomes as it drops out of the Great Lakes. Forecasters at LWX note a large reservoir of instability (MLCAPE 3000-4000+ J/kg) upstream, riding beneath a strong 100+ kt jet streak — the ingredients are there for an organized line capable of damaging winds, especially if it stays potent through the evening hours. A slower, more disorganized arrival would mean a lower but still real risk of isolated damaging gusts, particularly in western and central Maryland before the atmosphere stabilizes overnight. SPC keeps the whole area in a Slight Risk (level 2 of 5), same story continuing into Friday. Flash flooding is a secondary, lower-confidence concern — storm motion should keep training/repeat activity limited, but any slow-moving cell could produce brief localized ponding.
Heat & Humidity
Today’s highs ran from near 84° in the Garrett County mountains to the low-to-mid 90s across the Cumberland/Hagerstown area, central Maryland, and the Upper Shore (Easton hit 94°, Baltimore/DC-area 93°). Dew points in the low-to-mid 70s kept heat indices climbing into the upper 90s to around 100-103° for a good chunk of the state, enough to justify continued Heat Advisories on the Shore. That mugginess doesn’t fully break overnight — it’ll just feel like a warm, damp blanket rather than a full-blown heat event once the sun goes down.
Winds & Chesapeake Bay
Winds stay generally light tonight, mostly west to southwest at 5-10 mph away from any storm outflow. The exception is inside any thunderstorm core, where gusts could spike suddenly and sharply — that’s the real wind story tonight, not the ambient breeze. On the Bay and tidal Potomac, boaters should treat any approaching storm cell as a signal to head for harbor; outflow winds from these storms can arrive well ahead of the rain.
Overnight Lows by Zone
| Zone | Low |
| Western mountains (Garrett) | Around 65° |
| Cumberland/Hagerstown | Low-to-mid 70s (71-72°) |
| Frederick/Carroll | Around 72° |
| Baltimore/DC corridor | Mid 70s (74-76°) |
| Southern Maryland | Around 74° |
| Eastern Shore | Mid 70s (74-75°) |
| Ocean City | Around 75° |
Looking Ahead
Friday: More hot, humid, and unsettled weather, with highs back into the upper 80s to lower 90s across most of the state (mountains cooler, near 80°). Another round of showers and storms is likely, some possibly severe with damaging wind gusts and hail, mainly afternoon into evening — LWX notes the threat axis may shift a bit farther north this time, closer to I-70/the Mason-Dixon Line. Saturday and the Labor Day weekend: Good news — drier air finally works in behind Friday’s storms. Highs ease into the lower-to-mid 80s inland and 70s on the coast, with lower humidity and mostly sunny skies expected for Sunday and Labor Day itself. A well-earned break after a stormy stretch.
Data: NWS Baltimore/Washington, Mount Holly & Wakefield.
MD Weather Alerts — tracking every county, every night. Stay safe out there, and keep an eye on the sky before you turn in.