As low pressure spins off the Mid-Atlantic coast, an inland stream of showers and rain bands continues. One to five inches of rain (with isolated higher amounts) have fallen across the region since Wednesday, with most locations in the two to four inch range.
Officially, through 2 p.m.. Reagan National Airport had picked up 2.90″, Dulles 3.80″ and BWI, 5.40″ since Wednesday. BWI has received 3.09″ today alone, shattering its daily rainfall record of 1.13″ (from 2002). There have been a few reports of flooding near BWI Airport, as well to the northwest in Carroll County.
This storm, composed of the remnants of tropical storm Karen as well as the weather system responsible for the South Dakota blizzard and Iowa-Nebraska tornado outbreak, formed Tuesday off the coast of the Carolinas and has barely budged since that time.
It’s been stuck due to a pair of high pressure systems, one to the north and one to the east. These highs have put on a squeeze play, keeping our coastal low more or less stationary.
While not particularly intense, the storm has been able to tap abundant moisture, some off the warm Gulf Stream, and spray it back onto land like a fire hose. Today, some of the rainfall has been enhanced by a small-scale area of low pressure that formed from a high altitude eddy, or area of spin, over southern Maryland.
This disturbance will exit the region later today and we should see a reduction in the coverage and intensity of rain.
Still, another 0.25-0.5″ of rain is possible through tonight, with locally heavier amounts of over an 1″. On Saturday, there’s a chance of scattered showers, but totals should average 0.25″ or less.