Maryland will experience another hot and humid day today, with a mainly dry morning followed by scattered showers and thunderstorms during the afternoon and evening.
Friday’s storms may become somewhat stronger and more organized than Thursday’s activity. A passing upper-level disturbance will provide additional lift, while stronger wind shear may allow storms to maintain themselves longer.
Not every community will receive a storm, but any storm that develops may produce damaging wind gusts, large hail, torrential rainfall and localized flash flooding. The greatest storm coverage is expected from mid-afternoon through the evening.
Statewide Overview
The day begins warm, humid and mainly dry.
Patchy fog may affect Western Maryland valleys and communities that received rain Thursday evening. Fog should gradually lift after sunrise.
Temperatures will climb rapidly, reaching the upper 80s and lower 90s across most of Maryland by early afternoon. Heat indices will generally reach the upper 90s to lower 100s.
Thunderstorms will initially develop over Western Maryland and the higher terrain before spreading toward central and eastern Maryland later in the afternoon.
Morning Commute
Most of the morning commute will be dry.
Patchy fog may reduce visibility in Garrett, Allegany, Washington and western Frederick counties. Isolated fog is also possible anywhere substantial rain fell Thursday evening.
Motorists should be prepared for rapid visibility changes in valleys and near rivers.
Elsewhere, expect partly sunny skies, light southwest winds and rising humidity.
Midday Forecast
Most of Maryland remains dry through lunchtime.
Temperatures will already be in the middle to upper 80s across the Baltimore–Washington corridor and Eastern Shore. Western Maryland will be slightly cooler.
Clouds will increase over the mountains as the atmosphere becomes increasingly unstable.
Afternoon Forecast
Storms may begin developing over Western Maryland shortly after noon or during the early afternoon.
Coverage should increase across Washington, Frederick, Carroll, Montgomery and adjacent counties between approximately 2 PM and 5 PM.
Additional storms are expected to develop or move east toward Baltimore, Washington, Southern Maryland and the Eastern Shore during the late afternoon and evening.
A few storms may become severe.
Evening and Overnight
The greatest storm coverage across central and eastern Maryland may occur between approximately 5 PM and 9 PM.
Storms will gradually weaken later in the evening, although scattered activity may persist past sunset.
Friday-night lows will generally range from the middle 60s in the mountains to the middle and upper 70s near Baltimore, Washington, Southern Maryland and the Eastern Shore.
Patchy fog may redevelop overnight where heavy rain falls.
County-by-County Forecast
Garrett County
Patchy valley fog this morning. Scattered thunderstorms may develop by early afternoon.
Highs: 80–84°.
Storm hazards: Heavy rain, lightning and gusty wind.
Allegany County
Partly sunny and humid, with scattered afternoon storms.
Highs: 84–87°.
Washington County
Mainly dry through late morning. Storms become increasingly likely during the afternoon.
Highs: 87–90°.
Frederick County
Hot and humid with scattered storms after approximately 2 PM.
Highs: 88–91°.
A stronger storm may produce hail or damaging wind.
Carroll County
Partly sunny and hot. Scattered storms develop late afternoon or evening.
Highs: 88–91°.
Baltimore County
Hot and humid with thunderstorms possible after approximately 3–4 PM.
Highs: 89–92°.
Localized flooding and wind damage are possible.
Baltimore City
Hot and humid with highs around 91–93°.
Late-afternoon or evening storms may produce intense rain, lightning and strong wind.
Harford County
Partly sunny and humid with scattered late-day thunderstorms.
Highs: 88–91°.
Cecil County
Hot and humid with an increasing late-afternoon and evening storm chance.
Highs: 89–92°.
Montgomery County
Mostly sunny and hot through early afternoon. Scattered storms develop later.
Highs: 90–93°.
Howard County
Hot and humid with thunderstorms possible after approximately 3 PM.
Highs: 89–92°.
Prince George’s County
Mostly sunny and hot during the morning and early afternoon.
Scattered thunderstorms may develop late.
Highs: 90–93°.
Anne Arundel County
Partly sunny and humid with thunderstorms possible late afternoon or evening.
Highs: 88–91°.
Charles County
Hot and humid with isolated to scattered late-day storms.
Highs: 89–92°.
Calvert County
Partly sunny and humid with a late storm possible.
Highs: 87–90°.
St. Mary’s County
Warm and humid with scattered late-day storms possible.
Highs: 87–90°.
Kent County
Mostly sunny and hot early. Storm chances increase during the evening.
Highs: 89–92°.
Queen Anne’s County
Hot and humid with scattered late-day thunderstorms possible.
Highs: 89–92°.
Talbot County
Partly sunny and humid. Evening storms are possible.
Highs: 88–91°.
Caroline County
Hot and humid with an increasing storm chance late.
Highs: 90–93°.
Dorchester County
Partly sunny and humid with afternoon or evening storms possible.
Highs: 88–91°.
Wicomico County
Hot and humid. Thunderstorms may develop late in the day.
Highs: 90–93°.
Somerset County
Partly sunny and humid with a late-day storm possible.
Highs: 88–91°.
Worcester County
Mostly sunny and hot inland, with late-day storms possible.
Inland highs: 89–92°.
Ocean City: 84–87°.
Storm Timing
Before noon: Mainly dry statewide.
Noon–3 PM: Storms begin developing over the western mountains.
3–6 PM: Storms expand into north-central and central Maryland.
6–9 PM: Greatest coverage around the Baltimore–Washington corridor, Southern Maryland and Eastern Shore.
After 9 PM: Storms gradually diminish.
Severe-Weather Risk
A few storms may become severe.
Damaging straight-line wind gusts will be the primary threat, but the atmosphere may also support large hail.
The severe risk will depend on how much sunshine occurs before storms develop and whether outflow boundaries help storms organize.
The threat is not uniform, but stronger storms could cause localized tree damage and power outages.
Flooding Risk
Tropical moisture remains in place, with precipitable-water values near or above two inches in parts of the region.
Storms may produce torrential rainfall over short periods. Localized flash flooding is possible in urban areas, near small streams and in communities receiving repeated storms.
Widespread river flooding is not expected.
Heat and Humidity
Temperatures will reach the upper 80s and lower 90s across most of Maryland.
Heat-index readings will generally range from the upper 90s to lower 100s.
Outdoor workers and athletes should drink water frequently, schedule breaks and watch for signs of heat exhaustion.
Wind Forecast
Outside thunderstorms, southwest winds will generally remain around 5–12 mph.
Storms may produce abrupt gusts exceeding 50 mph.
Fog
Patchy fog is possible during the morning across Western Maryland and again overnight in locations receiving rain.
Fog may briefly become dense in valleys.
Chesapeake Bay and Tidal Potomac
Southwest winds will generally remain around 5–15 knots.
Thunderstorms may produce gusts above 35 knots, frequent lightning and sharply reduced visibility. Special Marine Warnings may be required.
Maryland Beaches
Ocean City and Assateague will be sunny, hot and humid with highs in the middle 80s.
A Moderate Rip Current Risk is forecast Friday. Surf will be approximately 2–3 feet, with southwest winds around 10–15 mph.
Only enter the water near a lifeguard.
Coastal Flooding
Persistent southerly flow may gradually elevate Chesapeake Bay and tidal Potomac water levels.
Minor flooding may become possible at the most sensitive shoreline locations during high tide, but no widespread coastal-flooding event is currently expected.
Air Quality
AirNow observations across Maryland are generally in the Good to Moderate range.
Ozone may reach Moderate levels in some areas before afternoon storms develop. No statewide unhealthy-air emergency is indicated.
Winter Weather
There are no winter-weather concerns.
Tropical Weather
No direct tropical-cyclone impact is expected.
The air mass is tropical in character and capable of producing very high rainfall rates, but the storms are not associated with a direct tropical-system landfall.
Active Watches, Warnings and Advisories
At the source check:
- NWS Baltimore/Washington’s Hazardous Weather Outlook identified a few strong to severe thunderstorms Thursday evening and continued damaging-wind and isolated flash-flood potential Friday and Saturday.
- No general Maryland Heat Advisory was listed by the offices covering Maryland.
- A Moderate Rip Current Risk is forecast Friday for Ocean City and Assateague.
- Marine thunderstorms may prompt Special Marine Warnings.
Warnings may be issued quickly as storms develop, so residents should monitor the latest NWS alert feed throughout the afternoon and evening.
Looking Ahead
Saturday may bring another active storm period, potentially with stronger or more organized severe thunderstorms.
Damaging wind gusts and localized flash flooding will remain the main concerns.
Sunday may offer a relative decrease in storm coverage, but hot and humid weather will continue. Daily storm chances return next week.