The Washington PostDemocracy Dies in Darkness

Deluge possible for D.C.’s Thursday morning commute from giant ‘S’-shaped storm

Satellite image showing huge storm system approaching eastern U.S. on Wednesday, Nov. 18, 2015. (NASA)

The same storm system spawned vicious tornadoes in the central U.S. and a blizzard in Colorado darts into the D.C. metro area late tonight and Thursday morning. As it sweeps through, heavy rain is likely – timed inconveniently for Thursday morning’s rush hour.

Satellite imagery (above) reveals the enormity of the storm system, which spans from central Mexico to Baffin Island, Canada. The storm is drawing up a plume of moisture from the subtropics which extends almost 3,500 miles to the north.

Models suggest the heaviest rain in the D.C. region will fall around 4-7 a.m. west of I-95 and 7-10 a.m. east of I-95. Some embedded thunder and a strong wind gust or two (up to 30-40 mph) cannot be ruled out as this all comes through.

Rainfall totals are likely to be about 0.5-1.0 inches which may cause some ponding of water on the roads and low visibility for a time, but widespread flooding is not expected.

The bulk of the rain may be over by midday Thursday, although it’s not out of the question that a narrow line of showers – maybe with a bit of thunder – zips through later during the afternoon when the actual cold front passes. But don’t be surprised if we see a good deal of sunshine in the afternoon with temperatures surging well into the 60s before the cooler air arrives Thursday night into Friday.

Below, find model rainfall forecasts. Note they are pretty consistent in simulating 0.5-1.0 inches.

NAM model: 0.6-0.9 inches

High resolution NAM model: 0.3-1.0 inches

GFS model: 0.8-1.0 inches

European model: 0.4-1.0 inches