Severe Storm Threat Builds This Afternoon Statewide

Good morning. Today’s the day the forecasters have been circling on the calendar all week. NWS Baltimore/Washington (issued 3:38 AM), NWS Mount Holly (4:28 AM), and NWS Wakefield (2:58 AM) are all singing the same tune this morning: a slow-moving cold front and a deepening mid-level shortwave are going to squeeze the entire state — but especially the I-95 corridor east to the Chesapeake Bay — into a corridor of numerous, potentially severe thunderstorms this afternoon into this evening. Damaging wind gusts, a few tornadoes, and heavy, flooding rainfall are all on the table. No watches or warnings are up as of this writing, but that’s very much a placeholder — expect that to change as the day heats up and instability builds.

Timing

• Early morning: Mostly quiet, with a few weak, elevated showers possible near western Maryland from warm-air advection. Patchy fog lingering in the mountains.
• Late morning into midday: Convection begins to fire, especially along and west of the Blue Ridge/Catoctin ridgeline as the shortwave’s leading edge pushes across the Appalachians.
• Early-to-mid afternoon: Instability ramps up sharply along and east of I-95. This is when the risk turns serious — deep, moist, well-sheared storms capable of damaging winds, a few tornadoes, and torrential rain rates become likely from the DC metro north into the Baltimore area and out toward the Bay.
• Mid-to-late afternoon into evening: Peak severe window. Multiple rounds possible in the same spots thanks to regenerating storms along outflow boundaries, bay breeze convergence, and the front itself. Urban/poor-drainage flash flooding is a real concern in the Baltimore corridor and northeast Maryland. The Eastern Shore, including Ocean City, joins in by mid-afternoon as the front’s influence spreads east across the Bay.
• Overnight: Activity gradually wanes from west to east as the front slides through, though a few lingering showers can’t be ruled out toward the Shore.

Region by Region

Western Maryland

Garrett County (Deep Creek/Oakland) tops out around 71°, with a high (87%) chance of showers and thunderstorms and patchy fog lingering into the morning — this is more soggy than severe, since the sharpest instability and shear stay east of the Blue Ridge. Allegany County (Cumberland) runs warmer, near 78°, with an even higher 97% coverage of showers and storms; some of these could still be locally strong given the shortwave’s track over the mountains around midday, but the classic severe ingredients (deep shear, high CAPE) are notably weaker out here than toward the I-95 corridor. Expect a wet, gray day west of the ridgeline with lows dropping into the low-to-mid 60s tonight (60-61°).

Northern & Central Maryland

Washington County (Hagerstown) climbs to near 79°, with an 88% chance of showers and thunderstorms — isolated activity in the morning becoming more widespread and potentially strong by afternoon. Frederick and Carroll counties see a similar setup: high near 80°, 89% coverage, trending from isolated to numerous storms as the afternoon wears on. This zone sits right at the transition where the severe threat starts to sharpen — closer to the Blue Ridge/Catoctin corridor means somewhat less organized severe potential than points east, but still enough instability and lift for a strong storm or two, especially later in the afternoon. Lows tonight fall into the low-to-mid 60s (63-64°).

Baltimore Metro

This is ground zero. Baltimore City and County, Harford, Howard, and Anne Arundel counties all warm into the mid-80s (gridpoint high near 85°), with a 92% chance of showers and thunderstorms — starting isolated in the morning, turning widespread and potentially severe by afternoon into evening. This is the area the discussions keep circling back to: strongest large-scale ascent, best combination of shear and moisture, and an urban footprint that’s already seen heavy rain recently, which raises a real flash flood risk on top of the wind and tornado threat. Lows tonight settle in the upper 60s (68°) under patchy fog once the storms clear out.

DC Suburbs

Montgomery and Prince George’s counties run hot ahead of the front, with a high near 86° — the warmest reading on the board — and an 83% chance of scattered showers and thunderstorms. This area sits square in the zone the LWX discussion flags as most likely to see multiple rounds of storms, driven by low-level convergence and outflow boundaries layering on top of each other through the afternoon and evening. Any storm that fires here has access to the richest low-level moisture in the state, so don’t be surprised if cells intensify quickly. Lows tonight dip into the upper 60s (67°).

Southern Maryland

Charles, Calvert, and St. Mary’s counties see the day’s highest temperatures, climbing to near 88° ahead of the front, with an 87% chance of scattered showers and thunderstorms this afternoon and evening. Confidence in the severe threat here is a touch lower than immediately around DC and Baltimore — the LWX discussion specifically calls the threat a bit more conditional toward the Annapolis/Beltway zone and points south — but the heat and humidity building ahead of the front mean any storm that does fire has plenty of fuel. Lows tonight hold in the upper 60s (68°) under partly cloudy skies once the front clears.

Eastern Shore & Ocean City

Cecil, Kent, Queen Anne’s, Talbot, and Caroline counties (Upper Shore, near Easton) reach a high near 88°, with a 67% chance of showers and thunderstorms this afternoon becoming likely tonight (84%) as the front’s energy pushes east across the Bay — the AKQ discussion also keeps a Slight Risk excessive rainfall outlook over the Eastern Shore, so a few of these storms could produce locally heavy downpours. Dorchester, Wicomico, and Somerset counties (Lower Shore, near Salisbury) run slightly cooler, near 87°, with a lower 46% chance of showers and thunderstorms today, rising to 43% overnight — this part of the Shore trails the main severe corridor but still gets in on the action, especially after dark.

Worcester County and Ocean City stay the coolest and driest spot on the map today, with a high near 82° under mostly sunny skies and only a 41% slight chance of an afternoon shower or storm, rising to 41% overnight. Southwest winds build from around 5 mph in the morning to near 15 mph by afternoon. At the beach: surf running 2 to 3 feet, rip current risk is low, and water temps sit in the upper 70s — a fine beach day with just a chance of a passing shower. Low tide at the Ocean City Fishing Pier is 7:42 AM, with high tide at 2:13 PM.