Update: Tracking multiple rounds of dangerous storms tonight and Thursday

*Flash flood watch midnight tonight through 8 p.m. Thursday*

By now you’ve probably heard about the potential for severe weather tonight and tomorrow. While we think the odds of a derecho as severe as the one we saw a year ago are low here in the D.C. area, there is a legitimate chance that at least parts of the area will see one or more rounds of strong to severe thunderstorms roll through from west to east (or northwest to southeast) between late tonight and Thursday evening.


Radar & lightning:Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

Round 1: Storms now firing in eastern Ohio, southwest Pennsylvania and northern West Virginia (see Midwest radar) may be the beginning of stuff headed our way. The most likely timing for the first round is tonight between 2 a.m. and 7 a.m., though thunderstorm timing is notoriously hard to pin down. Heavy rain and dangerous lightning are the main threat with this round, though strong winds are possible as well. But storms are not a sure bet, and they could end up isolated or scattered rather than a solid line.

Round 2: The most likely timing for the second round is between 2 p.m. and 7 p.m. (but again, timing thunderstorms is very difficult). Storms are a better bet for everyone with this round, though there are no guarantees, and they could easily be severe with damaging winds in addition to flooding rain and dangerous lightning.

Note: Isolated to scattered thunderstorms are possible between the two rounds (Thursday morning into early afternoon) and there’s enough spin in the air that some of these could spawn tornadoes. There also may be a 3rd round in the form of a solid line of quickly passing storms around mid-morning Thursday.

The RAP model shows the wave in the upper levels of the atmosphere at 9 p.m. this evening (circled in red) that will track east overnight into tomorrow and could bring a round of severe storms to the D.C. area Thursday afternoon into early evening.

The RAP model shows the wave in the upper levels of the atmosphere at 9 p.m. this evening (circled in red) that will track east overnight into tomorrow and could bring a round of severe storms to the D.C. area Thursday afternoon into early evening.

We encourage you follow our Twitter feed (which is simulcast above) and Facebook feed for additional updates this evening as warranted. If you’re up late tonight, you can track any storms and severe warnings on the map below. Scroll below the map for tips on how to prepare for the storms.

Preparedness

In light of the severe storm threat both tonight and tomorrow, consider taking the following actions:

* Prepare for possible power outages: Charge portable devices and phones, have flashlights ready to go, have fresh batteries, fill your car with gas, and have a plan in case outages are extended (lasting days).

* Move loose outdoor items inside or secure

* Clear storm drains and gutters for possible flash flooding

* Stay up-to-date on the latest storm warnings. Follow our blog, Twitter feed, and Facebook page. Also consider subscribing to our Twitter feed dedicated to *only* storm warnings: @DCWeatherAlerts. Other options: get a weather radio and/or download a smartphone app that will sound an alert if warnings are issued, such as IMAP Weather Radio.

Also on Capital Weather Gang

PM Update: Thunderstorm threat up tonight, highest tomorrow; 4th Maryland tornado