Damaging storms struck the D.C. region late last week, bringing strong winds, frequent lightning, and torrential downpours. The NWS Storm Prediction Center (SPC) issued a Severe Thunderstorm Watch at 0040 UTC 04 September, valid through 0600 UTC for “Scattered damaging wind gusts up to 70 mph possible”. A Severe Thunderstorm Warning was issued by NWS WFO Sterling at 0337 UTC for “70 mph wind gusts” that “will cause some trees and large branches to fall.”
GOES-East CONUS Geocolor Imagery, overlaid with the GLM Flash Extent Density (FED) showed a line of storms track southeastward from PA and WV before crossing the Mid-Atlantic. A cell approaching D.C. had a lightning jump before approaching the city. With the storm over the district, GLM FED values approached the top of the colorbar range (purples to light blues), observing 100-200 strikes over a grid cell (~8 km) within 5 minutes. The CIRA GOES-East Mesoscale GLM Group Energy Density product provided a complementary look, with very energetic flashes (bright white) coinciding with the high number of flashes seen in the FED product.
Figure 2: GOES-East CONUS GLM FED output, overlaid on GeoColor Imagery, from 0111-0651 UTC 04 September 2026. Credit: NESDIS/STAR
The intensifying storms were easily detectable in the GOES-East CONUS Band 13 Infrared (IR) Imagery, with rapidly cooling cloud tops as the convection entered Northern Virginia before pushing eastward into Washington, D.C., and Maryland.
Figure 4: GOES-East CONUS IR Imagery from 0101-0656 UTC 04 September 2026. Credit: NESDIS/STAR
Zoomed out to CONUS-scale, GOES-Derived Motion Wind (DMW)s indicated the overshooting cloud tops from the storm complex had wind speeds in excess of 50 knots at upper-levels (100-400 hPa), confirming the mature nature of the convection.
The GOES Mesosector Optical flow Code for Tracking, Atmospheric motion vectors, and Nowcasting Experiments (OCTANE) Speed Sandwich product allows for cloud motion to be determined by tracking subsequent satellite images. In the product output, a burst of higher cloud-top wind speeds (40-50 m/s, or ~80-100 knots) is seen expanding outward downstream of much slower wind speeds (10-20 m/s, or ~20-40 knots), signaling cloud-top divergence, and confirming the mature storm detected in the GOES DMW output.
Figure 6: GOES-East Mesosector OCTANE Speed Sandwich output from 0300-0437 UTC 04 September 2026. From CIRA Slider
Storm Reports from the NWS SPC confirmed hundreds of Wind Reports from Michigan to Delaware due to the long-lived line of storms, including a wind gust up to 71 mph in the D.C. suburb of Ballston, VA. Photos of damage in Washington, D.C. confirmed fallen limbs on vehicles along with downed trees and power lines.
