A severe thunderstorm about to impact the National Mall on September 8, 2012. Image is a multi-photo panorama. See larger.
We had a good idea intense storms would move across the region on Saturday as a strong cold front was pushed along by a powerful jet stream. While midday sunshine prepped the air, storms began to expand coming out of the mountains and became particularly intense on their way through the heart of the metro area.
Wind damage reports ended up fairly widespread. Peak wind gusts ranged from 55-70 mph. National Airport registered a 58 mph gust, exceeding severe wind criteria.
When I arrived near the National Mall around 2:45 p.m. (75 minutes or so before the storm hit), hints of what was to come were not too numerous. Some views offered rather crisp blue skies. But, for a careful observer, the signs of storminess were indeed increasing on the horizon, in the form of “anvils” blowing out ahead of the storms as well as a general increase in puffy convective clouds.
As the sky off to the west continued to become darker, thunderstorm warnings were issued a good 30+ minutes before their arrival. A tornado warning was also up just to the west, and skies continued to fill with scary looking clouds. Rain and wind were quick to start as a shelf cloud approached. Although lightning was not terribly frequent, the intensity of the storm persisted for some time.
Below are chronological images from the day, A short video as the storm hit is above.
Skies appear somewhat benign but the first sign of storms to the west can be seen in the high clouds fanned out in the distance, these are the anvils of thunderstorms. Image is a multi-photo panorama. See larger.
A plane approaches D.C. with a shelf cloud seen behind it. I’m not sure if the plane landed or was being redirected, but it seemed to come closer to the Lincoln Memorial than usual.
The shelf cloud marking the leading edge of outflow from the severe thunderstorm approaches the Potomac River. See larger.
Shelf cloud approaching Washington, D.C. See larger.
Shelf cloud approaching Washington, D.C. Image is a multi-photo panorama. See larger.
Shelf cloud passing over the Lincoln Memorial.
The storm begins to overtake the National Mall. See larger.
Rainfall and wind intensity picks ups as the storm continues to enter the city. See larger.