Maryland enters Friday under a more complicated weather setup.
A stalled frontal boundary remains to our south while disturbances continue traveling through northwest flow aloft. That combination brings more clouds and an increasing chance of showers or thunderstorms today—but the risk varies considerably across the state.
The highest rain and thunderstorm probabilities are expected across Southern Maryland, Western Maryland and portions of the lower Eastern Shore. Northern Maryland and the Baltimore region should see considerably more dry time.
Statewide Overview
Expect more clouds than Thursday.
High temperatures generally remain in the 80s, with upper 70s across the highest Western Maryland elevations and upper 80s around Baltimore, Washington and portions of the Eastern Shore.
A weakening disturbance may bring a few showers through western or southern portions of the state during the morning.
Scattered thunderstorms become possible during the afternoon and evening.
NWS Baltimore/Washington’s newest guidance says the stronger instability falls off quickly with northward extent, making areas south of U.S. 50 the more favored Maryland corridor for stronger convection.
Morning Commute
Most major Maryland commuting corridors should remain dry through much of the morning.
Cloud cover will be widespread.
A few showers may approach Garrett, Allegany and portions of Southern Maryland depending on how a weakening overnight thunderstorm complex evolves.
Patchy fog is possible in Western Maryland valleys.
Midday
Temperatures reach the upper 70s and lower/middle 80s.
Persistent clouds may suppress instability across Northern and Central Maryland.
The farther south you travel toward Southern Maryland and Virginia, the greater the chance for the atmosphere to become supportive of afternoon thunderstorms.
Afternoon / Evening
Scattered showers and thunderstorms develop.
The best current window is approximately 2–8 PM, although timing confidence is only moderate.
The strongest storms would be capable of damaging wind gusts and locally heavy rainfall.
Widespread severe weather is not expected across Maryland.
County-by-County Forecast
Garrett County: Mostly cloudy. Scattered showers, with thunderstorms possible. Highs mid-70s to around 80°, elevation dependent. Patchy morning fog possible.
Allegany County: Mostly cloudy with scattered showers/storms. Cumberland high around 84°.
Washington County: Mostly cloudy. Small late-day shower/storm chance. High around 84–86°. Hagerstown’s current NWS forecast carries only a 20% precipitation chance.
Frederick County: Mostly cloudy. High 84–87°. Isolated afternoon shower/storm possible.
Carroll County: Mostly cloudy. High 84–87°. Mainly dry with a small late-day rain chance.
Baltimore County: Mostly cloudy. High 86–89°. Isolated shower possible late.
Baltimore City: Mostly cloudy, high near 88°. NWS currently has only a 20% chance of a late-afternoon shower, with greater rain chances Friday night.
Harford County: Increasing clouds. High 85–87°. Low daytime rain chance.
Cecil County: Partly to mostly cloudy. High 85–88°. Small shower chance.
Montgomery County: Mostly cloudy. High 86–89°. Isolated afternoon/evening shower or storm possible.
Howard County: Mostly cloudy. High 86–89°. Small late-day rain chance.
Prince George’s County: Mostly cloudy. High 87–90°. Scattered afternoon/evening thunderstorms become more plausible.
Anne Arundel County: Mostly cloudy. High 85–88°. Scattered late-day shower or storm possible.
Charles County: Mostly cloudy. High 86–89°. Better afternoon/evening thunderstorm chance.
Calvert County: Mostly cloudy. High 84–87°. Scattered showers/storms possible later.
St. Mary’s County: Mostly cloudy. High 85–88°. Among Maryland’s higher afternoon/evening thunderstorm chances.
Kent County: Partly to mostly cloudy. High 85–88°. Air quality Code Yellow/Moderate.
Queen Anne’s County: Partly cloudy to mostly cloudy. High 85–88°. Air quality Moderate.
Talbot County: Partly sunny. High 85–88°. Scattered showers possible. Air quality Moderate.
Caroline County: Partly sunny. High 85–88°. Shower chance increases later. Air quality Moderate.
Dorchester County: Partly sunny. High 85–88°. Scattered afternoon showers/storms possible.
Wicomico County: Partly sunny. Salisbury high around 87°, with a 30% rain chance.
Somerset County: Partly sunny. High 85–87°. Scattered afternoon/evening showers possible.
Worcester County: Partly sunny. High 85–88° inland. Afternoon showers possible.
Ocean City: Partly sunny with a chance of showers. High mid-80s. Low Rip Current Risk, surf around 1 foot, water temperatures in the upper 70s.
Temperature Breakdown
Western mountains: mid-upper 70s
Cumberland: low-mid 80s
Hagerstown/Frederick: mid-80s
Baltimore/DC corridor: upper 80s
Southern Maryland: mid-upper 80s
Eastern Shore: mid-upper 80s
Ocean City: mid-80s
Rain / Storm Timing
6 AM–noon: Mostly cloudy; isolated showers possible west/south.
Noon–2 PM: Scattered showers begin increasing.
2–8 PM: Main thunderstorm window, particularly Southern Maryland.
Friday night: Scattered showers and a few thunderstorms remain possible.
Severe Weather
NWS Baltimore/Washington’s 2:48 PM EDT Thursday AFD says high-resolution guidance favors areas south of U.S. 50 for the better chance of stronger convection Friday. Damaging wind would be the primary hazard in any stronger storm.
The SPC Day 2 outlook issued 1:30 PM EDT Thursday carries a Marginal Risk across portions of the Mid-Atlantic. The more meaningful risk corridor extends into Virginia, while much of Northern Maryland sits closer to the northern edge of the unstable air mass.
Flooding
Widespread Maryland flooding is not expected.
Localized heavy rain remains possible with thunderstorms, especially across Southern Maryland and the lower Eastern Shore.
NWS Wakefield’s 3:04 PM EDT Thursday discussion notes a Marginal excessive-rainfall setup Friday across portions of its area. High precipitable-water values may support heavy downpours, although storm motion should limit widespread flooding.
Winds
Light easterly to northeasterly winds are favored.
Thunderstorms could briefly produce stronger gusts.
Fog
Patchy early-morning valley fog is possible in Western Maryland.
Widespread dense fog is not expected.
Heat / Humidity
Cloud cover limits the heat.
Most Maryland highs remain in the 80s and no Heat Advisory is currently indicated.
Humidity remains noticeable but far from the most oppressive levels of recent heat episodes.
Air Quality
The Maryland Department of the Environment forecast relayed by NWS Mount Holly at 3:45 PM EDT Thursday calls for Code Yellow/Moderate air quality Friday in Kent, Queen Anne’s, Talbot and Caroline counties, with particles as the primary pollutant.
No statewide Maryland air-quality alert is indicated in the official products reviewed.
Chesapeake Bay / Tidal Potomac
Background winds stay below Small Craft Advisory levels.
NWS Baltimore/Washington expects easterly/northeasterly flow Friday. Thunderstorms represent the primary localized marine hazard, especially across southern Bay waters.
Maryland Beaches
NWS Wakefield’s Surf Zone Forecast was issued 3:42 PM EDT Thursday, August 13.
For Ocean City and Assateague Friday:
Rip-current risk: Low
Surf: Around 1 foot
Water temperature: Upper 70s
High: Mid-80s
Wind: Northeast around 5 mph
Weather: Partly sunny with a chance of showers.
Coastal Flooding
No Chesapeake Eastern Shore tidal flooding is currently forecast.
NWS Mount Holly’s 4:32 PM EDT Thursday update expects only one final round of spotty minor tidal flooding around the New Jersey/Delaware Atlantic coast and Delaware Bay Thursday evening, specifically noting that tidal flooding is not forecast for Maryland’s Chesapeake Eastern Shore.
NWS Baltimore/Washington notes water levels will slowly increase over the next several days, with Annapolis potentially reaching Action Stage around Friday morning’s high tide, but no broader coastal flood headline is currently indicated.
Winter Weather
There are no winter-weather concerns anywhere in Maryland.
Active Watches, Warnings and Advisories
At publication time, no Maryland watches, warnings or advisories are carried in the latest LWX, PHI or AKQ forecast-office products reviewed.
This can change if stronger thunderstorms develop later today, particularly in Southern Maryland.
Look Ahead
Saturday looks quieter.
High pressure builds south from Canada, bringing lower thunderstorm coverage and highs generally in the low/mid-80s.
The next more significant unsettled period arrives Sunday into Monday, when another frontal system brings increasing shower and thunderstorm chances. Mount Holly notes the primary concern may eventually become heavy rain/flash flooding as atmospheric moisture climbs toward 2 inches, while LWX also notes some conditional severe-weather potential.