A major threat of severe weather is looming Thursday morning and into the afternoon, but the violent line of storms known as a derecho in the D.C. area remains somewhat unlikely at this point, ABC7's Jacqui Jeras says.
While the formation of a derecho remains possible at some point through Thursday afternoon, Jeras and the ABC7 weather team say that the likelihood of one impacting the greater D.C. area is still low.
"Until it actually becomes (a derecho), I would call it a complex of thunderstorms that will produce damaging winds," Jeras says.
By definition, NOAA says that a derecho is a widespread, long-lived wind storm associated with a fast-moving line of thunderstorms. A storm may be classified as a derecho if the storm extends for more than 240 miles and contains wind gusts of more than 58 miles per hour.
Last June 29, a massive derecho swept through the D.C. area, leaving several people dead, millions of dollars in damage and millions of customers without power for days.
ABC7 Chief Meterolologist Doug Hill says that he anticipates a line of storms to come through very early Thursday morning and that a risk for severe weather increases as Thursday goes along.
Thursday is when the forecast becomes a bit more unsettled. Jeras says that a large complex of thunderstorms will develop over the Midwest and spread into the lower Great Lakes and Ohio Valley region. After that, there are three possibilities for how the storm will impact us:
- The complex holds together and brings damaging winds and isolated tornadoes overnight and early Thursday morning for the D.C. area
- The complex goes north of the Washington region and into Pennsylvania
- The system fizzles out
That doesn't mean that the D.C. area is out of the woods for severe storms. In fact, a line of severe storms will develop midday Thursday and into Thursday afternoon, likely bringing widespread damaging winds and isolated tornadoes to some spots.
Jeras says that this storm presents a moderate threat for severe storms on Thursday. A Flash Flood Watch has been issued for the entire D.C. area starting at midnight Thursday.
"There is a higher level of confidence in an outbreak of severe weather (Thursday), including intense squall lines with widespread damaging winds."
The ABC7 weather team also recommends that people who own NOAA weather radios to be tuned in for not only tornado warnings but also for severe thunderstorm warnings, which can present dangerous conditions.