A strong cold front will race through the Mid-Atlantic region Tuesday, setting off showers and storms. A few could produce gusty winds and heavy downpours. Severe weather and the threat of damaging winds will probably be more isolated — with higher chances in our eastern areas.
While scattered showers could break out ahead of the front Tuesday morning, the period to watch for any heavier showers or storms is around midday. The showers and storms, likely concentrated along a squall line, are likely to pass quickly, with rain lasting less than an hour in most locations.
By late afternoon, most of the showers and storms will have likely left the region, east of the Chesapeake Bay.
A few of the heavier showers and storms may be able to draw down some strong winds aloft, producing gusts of at least 40 to 50 mph, not unlike Friday night. Also similar to Friday night, we can’t rule out an isolated tornado or two, mainly east of Interstate 95.
“Our chances of any severe storms depend critically on the timing of the warm front tomorrow,” Jeff Halverson, Capital Weather Gang’s severe weather expert, said in an email. “We will be wedged in a bit under cool and overcast conditions, not a very unstable atmosphere. There is perhaps a 2-4 hour window tomorrow . . . if the warm front can lift out ahead of the cold front’s arrival, we could destabilize enough for strong to severe activity along the squall line.”
Most model forecasts predict about 0.25 to 0.5 inches of rain as the line comes through. But amounts will vary. The line coming through may have gaps, meaning some areas see very little rain while others are quickly drenched with up to an inch.
The National Weather Service’s Storm Prediction Center did lower the risk of severe storms from slight to marginal for the Interstate 95 corridor and areas to the west. East and southeast of Interstate 95, the risk of severe storms remains in the slight category — which is the second-lowest level on its five-point scale.
The risk of severe storms is higher in our eastern areas because the line will be coming through during the afternoon, giving the atmosphere a chance to heat up a bit more and become more unstable. As the line of showers and storms encounters this more favorable environment, “the line should have a wind damage threat along the leading edge,” the Storm Prediction Center writes. “An isolated tornado threat will also be possible with rotating cells embedded in the line.”
Southern Maryland, Virginia’s northern neck, and the Delmarva, in particular, have elevated chances of turbulent conditions.