DELMARVA - Sunday will bring some relief from the extreme heat, but not from the weather hazards, as high humidity, heavy rain and thunderstorms remain a concern across Sussex County and areas south toward Ocean City.
Excessive Heat Warnings were canceled earlier after rain and thunderstorms brought cooler air into the region. Still, heat illness will remain a concern Sunday because of the recent stretch of dangerous heat. A Heat Advisory will be in effect from 8 a.m. to 8 p.m., with heat index values expected to climb into the upper 90s to near 100 degrees in many areas.
The morning may begin with leftover damp roads, clouds, patchy fog or mist in spots, especially where rain fell Saturday night. Conditions should improve for part of the day, but the atmosphere will remain very humid and unstable.
The greatest concern will come later Sunday into Sunday night, when rounds of showers and thunderstorms are expected to develop. Some storms could become strong to severe, especially across Delmarva and areas south of the stalled front. Damaging wind gusts will be possible, but the bigger concern may become heavy rain and localized flash flooding.
Rainfall rates in stronger storms could reach 1 to 2 inches per hour. If storms move over the same areas repeatedly, low-lying roads, poor-drainage areas and urban spots could flood quickly. Drivers should avoid flooded roads and be ready for sudden drops in visibility during heavy downpours.
Storms could continue through a good portion of Sunday night. While the severe weather threat should slowly decrease overnight, the flash flooding threat may continue into early Monday morning where heavier rain lingers.
By Monday morning, a frontal boundary is expected to remain stalled near the region. Cooler air will begin to build in, but the location of the front will determine how much relief Sussex County and coastal areas see. More widespread showers and storms are possible Monday, with the severe risk lower but the flood risk still elevated because some areas may be hit by multiple rounds of rain over several days.
Drier weather is not expected to fully return until the middle of the week, after the front finally pushes south of the area.
