10:40 p.m. update: A Flash Flood Warning has been issued for much of the D.C. area along and west of I-95 (see live warning and radar maps in our Severe Weather Tracking Station below). Not a good night to be out driving. If you must, do not try to cross a flooded road. Always remember, “Turn Around, Don’t Drown.” The Tornado Watch has been dropped except far south and southeast of D.C. where it continues until 2 a.m. for Stafford, Charles, St. Mary’s and Calvert counties.
9:55 p.m. update: While the severe thunderstorm and tornado threat has likely passed, the rain keeps piling up with several more hours to go. Flood and Flash Flood Warnings are in effect across many of the north and west suburbs (see map), some of which have already received over 2 inches of rain. The entire area remains under a Flash Flood Watch through late tonight with another 1-2 inches possible especially north and west of D.C. where lingering impacts are likely in the morning.
8:35 p.m. update: The Severe Thunderstorm Warning for the D.C. area has expired. Fortunately, we’re not aware of any severe reports or damage locally. The Tornado Watch remains in effect, until 2 a.m. if not cancelled earlier, though the threat seems limited except maybe a little higher for the eastern suburbs. We still do have a few more hours left of showers, and a Wind Advisory for gusts to 50 mph associated with the cold front stays in effect until 6 a.m. We also have a Flash Flood Warning that continues until 12:30 a.m. for northwest Montgomery, southeast Frederick, northwest Loudoun and far northwest Fauquier counties. Multiple road closures and water rescues have been reported in Frederick County.
8:15 p.m. update: Heavy showers with strong to perhaps some severe wind gusts are now over D.C. and I-95 and pushing east into Anne Arundel, Prince George’s and Charles counties. A Severe Thunderstorm Warning remains in effect for much of the area, though so far reports indicate wind gusts have been below 50 mph which is below severe criteria (that is good news, of course).
7:50 p.m. update: A Severe Thunderstorm Warning has been issued for most of the metro area until 8:30 p.m. as heavy showers and strong winds move west to east through the District and close-in suburbs over the next hour. Wind gusts to 60 mph+ are possible with this line. A Tornado Watch remains in effect until 2 a.m., though the severe thunderstorm and tornado threats may lessen after 10 p.m. or so.
See toward end of post below for earlier updates
Overview from 5:15 p.m.: Despite lots of clouds, it was about as toasty as it gets in January as warm air surged north ahead of a powerful cold front. Highs across the region mostly crested 70 degrees, including a record high of 72 at Dulles. A first batch of rain drenched a good part of the northern and western half of the area, but showers were spottier close to town. More widespread showers, some heavy and accompanied by strong winds, are likely overnight.
Through Tonight: As the front drives through the region, showers are likely through much of the night, possibly with a rumble of thunder here and there. While truly severe winds (57 mph+) are expected to be isolated at most, it’s still going to be rather windy. Widespread gust between about 40 and 50 mph are likely as the front passes.
The most consistent and heaviest rains should be over a majority of the area between about 9 p.m. and 3 a.m., but areas west will continue to see more activity prior to that, and scattered showers may float around ahead of the main batch of rain. Isolated flooding is possible, with the best chance out towards Loudoun and Frederick counties, which have already received 1 inch of rain in spots. Precipitation clears out by sunrise or before, with clouds diminishing after the rain ends. Lows should reach the low-to-mid 40s in the suburbs, maybe upper 40s downtown.
Tomorrow (Thursday): After a slight risk of a.m. showers, skies are partly cloudy during the day. It’s still windy behind the front, enough so that I wouldn’t be shocked to see the wind advisory extended further into tomorrow. Look for those sustained winds to end up near 20-30 mph during the midday, which should mean gusts into the 40 mph+ range are possible. Afternoon temperatures (we may have a near midnight high) are fairly steady off lows, mainly in the 40s, and probably ranging from about 42-48. D.C. might be up near 50. It’ll be a good reminder it’s still winter!
Keep reading for earlier updates...
7:25 p.m. update: The line of intense rain and strong to severe winds continues to close in on the Beltway and D.C. proper over the next 45 minutes or so. Currently the leading edge of the line is edging east into eastern Montgomery, central Fairfax and eastern Prince William counties. Some storms could be severe (watch the Twitter feed below for any warnings issued) with damaging wind gusts to 60 mph+. The severe threat may lessen after 10 p.m. or so. As we’ve mentioned earlier, this will not be an outbreak anywhere close to the magnitude of last June’s derecho.
6:40 p.m. update: A Tornado Watch has been issued for the D.C.-Baltimore area until 2 a.m. Severe storms currently to the southwest around the Charlottesville area are headed northeast and could spawn a few tornadoes locally this evening. A Tornado Watch means that conditions are favorable for tornado development, not that one is imminent.
5:45 p.m. update: Flash flood warning for the western two-thirds of Loudoun county and northwest Fauquier county until 9:30 p.m. (and to the northwest). 1.5 inches of rain has already fallen in some spots and another 1 to 2 inches are possible overnight. Creeks and streams may overflow banks and motorists should never attempt to cross a flooded roadway. Turn around, don’t drown.