Watches:Be Prepared! Conditions are favorable for severe weather - i.e. tornado, thunderstorm, flooding - in your area.
Warnings: TAKE ACTION! Severe weather has been seen on radar or reported to the National Weather Service and will directly impact your location.
Summer Weather Terms
Execessive Heat Warning is issued when the heat index value is expected to reach or exceed 110 degrees within the next 12 to 24 hours. An Excessive Heat Warning may be issued for lower criteria if it is early in the season or during a multi-day heat wave.
Severe Thunderstorm Warning is issued when severe thunderstorms are occurring or imminent in the warning area and Winds of 58 mph or higher AND/OR Hail 1 inch in diameter or larger.
Tornado Warning is issued when a tornado is imminent. When a tornado warning is issued, seek safe shelter immediately.
Red Flag Warning is issued to alert fire officials and firefighters of potentially dangerous fire weather conditions within the next 12 to 24 hours. They are issued when the following three criteria are met: 1. Surface relative humidity (RH) less than 30 % for VA and MD; RH less than or equal to 25% for WV AND 2. Sustained surface wind of 20 MPH or greater AND 3. 10-hour fuel moisture less than 8% for VA; less than or equal to 8% for MD and WV.
Flash Flood Warning is issued when flash flooding is imminent or occurring.
High Wind Warning is issued when the following conditions are expected: 1. sustained winds of 40 mph or higher for one hour or more OR 2) wind gusts of 58 mph or higher for any duration.