Thunderstorm chances return to Southern Maryland on Thursday, Aug. 27, as warmer temperatures and increasing humidity bring a more unsettled end to the workweek across Charles, Calvert and St. Mary’s counties.
The latest National Weather Service forecast calls for a partly to mostly sunny day with highs climbing into the upper 80s across much of the region. Scattered showers and thunderstorms will be possible, particularly during the afternoon, although the forecast does not suggest that Thursday will be an all-day washout.
In Charles County, the National Weather Service forecast for Waldorf calls for a high near 88 degrees with south winds around 6 to 10 mph. There is a 30% chance of showers and thunderstorms, with the best daytime opportunity currently centered around the afternoon.
Farther south, Leonardtown is also expected to reach about 87 degrees. The latest forecast gives St. Mary’s County a slight chance of showers and thunderstorms during parts of the morning, followed by another chance late in the afternoon. South winds should generally remain between 5 and 9 mph.
Forecast confidence has changed considerably during the past several days. Earlier National Weather Service guidance had suggested a much wetter Thursday, with rain chances as high as 80% in portions of Southern Maryland. More recent forecasts have lowered daytime precipitation probabilities as updated weather data has become available.
That means residents should not expect continuous rain across the three counties. Instead, Thursday is increasingly looking like a warm and humid day with periods of sunshine interrupted by isolated or scattered showers and thunderstorms.
Where a thunderstorm does develop, conditions can change quickly. Brief downpours, lightning and locally gusty winds are possible with summer thunderstorms even when precipitation chances are relatively low.
Residents with outdoor plans should pay particular attention during the afternoon and evening. A 30% rain chance does not mean it will rain for 30% of the day or that every community will receive precipitation. Scattered thunderstorms can affect one part of a county while nearby areas remain completely dry.
Rain chances increase after sunset.
The National Weather Service gives Waldorf a 50% chance of showers and thunderstorms Thursday night. Leonardtown also has a 50% chance of showers and thunderstorms Thursday night, with mostly cloudy skies and temperatures falling to around 70 degrees.
The evening forecast could be particularly important for high school sports practices, community events and other outdoor activities as students across Southern Maryland settle into the new school year.
Anyone who hears thunder should move indoors. Lightning can strike well outside the area experiencing the heaviest rainfall, and outdoor activities should not resume until thunderstorms have safely moved away.
Temperatures Thursday will also be several degrees warmer than the cooler start to the week. Afternoon readings around 87 to 88 degrees combined with rising moisture will make conditions feel increasingly humid, although current forecasts do not indicate the type of extreme heat experienced at other points this summer.
No widespread National Weather Service watch or warning was in effect for Southern Maryland for Thursday at the time of this forecast. The lack of an alert does not eliminate the possibility of thunderstorms; watches and warnings are issued when hazardous conditions become sufficiently likely or imminent.
The forecast remains subject to additional changes as Thursday approaches. The significant reduction in daytime rain probabilities since earlier forecasts illustrates why residents with weather-sensitive plans should check the latest conditions rather than relying on forecasts issued several days earlier.
Friday is expected to remain warm, with additional isolated shower or thunderstorm chances possible in parts of Southern Maryland.
The Southern Maryland Chronicle will continue monitoring forecasts and any watches or warnings affecting Charles, Calvert and St. Mary’s counties.
