Tonight is a soggy, mutter-under-your-breath kind of night across Maryland. NWS Baltimore/Washington (2:10 PM update) and NWS Mount Holly (5:13 PM update) both describe a lifting warm front and organizing low pressure system dragging tropical-grade moisture (PWATs pushing 2 to 2.25 inches) up the I-95 corridor and over the mountains, with widespread showers and thunderstorms — some capable of dumping 1 to 2 inches of rain in a short window between roughly 1 AM and 7 AM Sunday. Garrett County is already dealing with it: a Flash Flood Warning is active there right now, layered atop a broader Flood Watch covering the western high country. Everyone else should expect a wet, warm, close night with storms arriving in waves.
Timing: Hour by Hour
- Now–8 PM: Scattered showers and a few storms ongoing, focused west of the Appalachians (Garrett/Allegany) with a flash flood risk already realized in Garrett. Isolated development possible along the I-95 corridor as the evening warm conveyor spins up.
- 8 PM–Midnight: Coverage increases statewide as the warm front lifts north. Central Maryland and the Baltimore-DC corridor see showers and rumbles of thunder build in from the south and west. Slow-moving cells raise localized flooding concern, especially on saturated western slopes.
- Midnight–4 AM: This is the meat of it. Low pressure organizes and lifts from around Delmarva toward Long Island, dragging a 6-8 hour window of heavy convective rain across the I-95 corridor and urban/small-stream areas. Localized 1-2 inch totals are plausible, especially Baltimore metro into the Eastern Shore.
- 4 AM–7 AM Sunday: Activity consolidates and shifts into northeastern Maryland (Harford/Cecil) before pulling off toward the northeast. Patchy dense fog develops in its wake, especially where the heaviest rain fell.
- Sunday morning onward: Showers taper from west to east; drier, cooler air starts working in behind the departing system ahead of Monday’s frontal passage.
Region by Region
Western Maryland
Garrett County (Deep Creek/Oakland): Lows near 61°, mid-60s at best for stretches. Showers and thunderstorms continuing overnight (90% chance) — this is ground zero, with a Flash Flood Warning already posted and a Flood Watch layered over the top given saturated soils and slow-moving storm training along the Alleghenies. Winds light, southwest 0-3 mph. Do not drive through flooded roads tonight.
Allegany County (Cumberland): Lows around 66°, wind light out of the east. Showers and thunderstorms likely (89%), also under the Flood Watch for the extreme western county. Rainfall could be locally heavy before drier air noses in toward Sunday.
Northern & Central Maryland
Washington County (Hagerstown): Low near 68°, scattered showers and thunderstorms (88%) transitioning to patchy fog toward dawn. Southerly winds 2-8 mph keeping things muggy.
Frederick & Carroll Counties: Low around 69°, similar setup — scattered storms overnight (87%) then fog develops as rain tapers before sunrise. Any heavier cell could produce quick ponding on rural roads.
Baltimore Metro
Baltimore City & County, Harford, Howard, Anne Arundel: Low near 72° — this is the muggiest stretch of the state tonight. Scattered showers and thunderstorms with a 91% chance, and this corridor is specifically flagged by both NWS offices for the flash flood concern given the overnight window of heavy convective rain (potentially 1-2 inches in spots). Patchy fog develops toward daybreak as rain winds down. Small streams and poor-drainage spots in the city could see quick flooding.
DC Suburbs
Montgomery & Prince George’s Counties: Low near 69°, scattered showers and thunderstorms (90%) overnight with the same flash-flood-attentive corridor risk as Baltimore. Southerly flow keeps dew points elevated into the upper 60s/low 70s range mentioned by Mount Holly.
Southern Maryland
Charles, Calvert, St. Mary’s: Low around 70°, showers and thunderstorms likely overnight (85%), some locally heavy given tropical moisture streaming up the Bay. Southerly winds 3-9 mph.
Upper Eastern Shore
Cecil, Kent, Queen Anne’s, Talbot, Caroline: Low near 70°, chance showers and thunderstorms (89%) overnight with southeast winds 5-10 mph. This zone is also in the path of the early-morning consolidation of activity as the low lifts northeast — Cecil in particular could see renewed storms closer to sunrise.
Lower Eastern Shore
Dorchester, Wicomico, Somerset: Low around 71°, showers and thunderstorms overnight (80%), muggy with southeast winds 3-9 mph. Slow-moving storms could produce brief heavy downpours, especially toward the Salisbury area.
Ocean City & the Coast
Worcester County: Low near 73°, showers and thunderstorms tonight (78% chance) with southeast winds around 13 mph — breezy and unsettled at the coast. Surf running 2-3 feet; the Moderate Rip Current Risk in effect this evening eases back to Low by Sunday as winds back around to the southwest. Tides: low around 3:09 PM today at the Ocean City Fishing Pier, next high near 9:35 AM Sunday. Swimmers should still heed posted flag warnings tonight and use caution given the surf and lingering rip risk.
Active Hazards
Flash Flood Warning (Severe) — Garrett County: In effect now. Slow-moving thunderstorms over saturated ground are producing rapid runoff. Avoid low-lying roads and never drive through flooded crossings.
Flood Watch (Severe) — Extreme Western Allegany, Western Garrett, Eastern Garrett: Continues through the overnight as repeated rounds of heavy rain raise the threat of additional flash flooding across the far western counties. This watch could be extended or upgraded depending on how training storms behave near the Allegheny Front.
Moderate Rip Current Risk — Maryland Beaches (Ocean City/Assateague): In effect until 8 PM this evening; risk drops to Low for Sunday, but swimmers should still exercise caution given onshore southeast flow.
Severe & Flash Flooding Threat
The core concern tonight is flash flooding, not classic severe wind/hail criteria. Two convective complexes are in play: one over the West Virginia/western Maryland high country where saturated soils and slow storm motion are already producing flooding in Garrett County, and a second forming along the I-95 corridor as instability builds ahead of the lifting warm front. How these two areas of storms interact will determine whether the flash flood risk expands eastward overnight — confidence is highest for western Maryland, moderate for the I-95 urban corridor between midnight and 7 AM. A few embedded rumbles of thunder are possible with any of these clusters, but this is fundamentally a heavy-rain, flood-watch event rather than a severe wind/hail setup.
Heat, Humidity & Winds
Muggy is the word for tonight — dew points are climbing into the 60s and low 70s statewide as southerly flow taps deep tropical moisture (PWATs near 2-2.25 inches per Mount Holly). It will feel close and heavy, especially in the Baltimore-DC corridor and across Southern Maryland. Winds stay generally light out of the south to southeast, 5-15 mph, with locally gustier winds near thunderstorm cores. Expect a noticeable humidity drop by Monday behind the front.
Chesapeake Bay & Marine
Southerly winds around the Bay and Tidal Potomac tonight support choppy conditions with embedded thunderstorm gusts possible. Boaters should watch for fast-developing storm cells, especially overnight into early Sunday morning as the low organizes offshore of Delmarva. Conditions improve markedly by Monday as northwest winds usher in drier, more stable air, though gusts of 15-25 mph are possible Monday afternoon.
Overnight Lows by Zone
| Zone | Low Tonight |
| Western Mountains (Garrett) | Around 61° |
| Cumberland/Hagerstown | Mid-to-upper 60s |
| Frederick/Carroll | Around 69° |
| Baltimore/DC Corridor | Low-to-mid 70s (Baltimore ~72°, DC suburbs ~69°) |
| Southern Maryland | Around 70° |
| Eastern Shore | Around 70-71° |
| Ocean City | Around 73° |
Looking Ahead
Sunday: Morning showers/storms taper from west to east with patchy fog burning off. Behind that, highs push into the mid-80s to upper 80s statewide (Cumberland and Baltimore both around 87°, Hagerstown/Frederick near 86°), with lingering afternoon shower/storm chances especially across the Eastern Shore (68% Easton, 65% Ocean City) as the cold front approaches. A weak downslope breeze helps warm things up ahead of the boundary.
Monday: The cold front crosses overnight Sunday into early Monday with limited storm chances — mainly some showers and a rumble along the Alleghenies. Behind it, Monday turns noticeably drier and more comfortable: highs mid-70s to low 80s, northwest winds gusting 15-25 mph, and humidity dropping fast. Monday night lows fall into the 40s and 50s across most of the state — the first real taste of fall air this season.
Beyond that: Tuesday and Wednesday look seasonably warm and notably dry as high pressure builds in, with dew points possibly dipping into the upper 40s Tuesday morning. Attention then turns to a cold front that may arrive Thursday into Friday, bringing another round of showers and possible thunderstorms — timing remains uncertain and we’ll keep tracking it.
Data: NWS Baltimore/Washington, Mount Holly & Wakefield.
Stay dry out there, Maryland — MD Weather Alerts will have you covered through the overnight and into Sunday’s clearing trend.