Tornado in metropolitan DC

July 5th, 2022 |
GOES-16 Band 13 infrared (10.3 µm) imagery, 2001 – 2256 UTC, 5 July 2022 (Click to enlarge)

GOES-16 infrared (above) and visible (below) imagery late in the afternoon of 5 July 2022 show the development of convection in between Baltimore and the District of Columbia. Tornadoes occurred in both Prince George County, just east and north of the District of Columbia, and over Anne Arundel county, just south of Baltimore (SPC Storm reports from 5 July). The storms that spawned these tornadoes (between 2130 UTC and 2200 UTC) developed quickly between DC and Baltimore, with tops cooling to about -55oC. Note that a parallax shift (to the south-southeast, towards the GOES-16 sub-satellite point at 0o N, 75.2o W) should be applied to these images to georeference them properly to the Earth’s surface. The repetitive re-development of cooler cloud tops between DC and Baltimore from 2100 – 2300 UTC suggests some kind of boundary to focus development in that region.

GOES-16 Band 2 infrared (0.64 µm) imagery, 2001 – 2256 UTC, 5 July 2022 (Click to enlarge)

NOAA/CIMSS ProbSevere (v. 3) — available at this website (and in AWIPS at select NWS Offices) was useful for this storm in that it showed highest values with the radar object associated with the tornado, thus conveying information to a forecaster (or radar operator) on which cell to investigate most thoroughly. The radar cell that spawned the tornado consistently had ProbSevere values exceeding 40%, compared to values in the 10-20% range for other radar objects.

ProbSevere (v. 3) display at 5-minute time-steps, 2000 – 2200 UTC on 5 July 2022 (Click to enlarge)

The ProbSevere website includes links to print out time series plots of particular radar objects. For this event, analysis is a bit complicated because the radar object was assigned a new ID value between 2100 and 2105 UTC, perhaps associated with the radar object splitting, as shown in this 2100/2105 UTC toggle, when the radar object was northeast of DC and southwest of Baltimore.

ProbSevere readout for Radar Object #571697, ca. 2000 – 2100 UTC on 5 July 2022 (Click to enlarge)
ProbSevere readout for Radar Object #572387, ca. 2100 – 2300 UTC on 5 July 2022 (Click to enlarge)

ProbSevere (v. 3) on this data gave useful information in highlighting the advanced threat with this particular cell compared to surrounding radar cells.

This event was also written up in the Washington Post (link). (Thanks to my sister for sending me the link!) Severe Thunderstorm warnings with the severe cell were issued at 2055 UTC (expiring at 2145 UTC), and at 2118 UTC (expiring at 2215 UTC); the first tornado warning was issued at 2121 UTC (expiring at 2145 UTC). The cell that produced the tornadoes had a long warning history.

Derecho in the Northern Plains

July 5th, 2022 |

GOES-16 “Red” Visible (0.64 µm) images, with time-matched SPC Storm Reports plotted in red [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) include time-matched SPC Storm Reports — and showed a large Mesoscale Convective System (MCS) that moved southeastward across the Northern Plains on 05 July 2022. This MCS produced damaging straight-line winds as strong as 99 mph and hail as large as 4.00 inches in South Dakota — in fact, with such a long path of strong straight-line winds this event was classified as a derecho.

In the corresponding 1-minute GOES-16 “Clean” Infrared Window (10.35 µm) images (below), pulsing overshooting tops exhibited infrared brightness temperatures of -80ºC or colder (purple pixels embedded within interior shades of black-to-white).

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animated GIF | MP4]

A comparison of Infrared Window images from NOAA-20 (11.45 µm) and GOES-16 (10.35 µm) valid at 2009 UTC — with identical color enhancements (below) revealed (1) the higher spatial resolution of NOAA-20 VIIRS (~375 m) sensed significantly colder cloud-top infrared brightness temperatures (-88ºC with NOAA-20, vs -78ºC with GOES-16), and (2) a NW displacement of features in the GOES-16 image, associated with parallax that is an inherent characteristic of geostationary imagery at higher latitudes and/or larger satellite viewing angles.

Infrared Window images from NOAA-20 (11.45 µm) and GOES-16 (10.35 µm), valid at 2009 UTC [click to enlarge]

The Electra Fire in California

July 5th, 2022 |

The Electra Fire near Jackson, California began on the afternoon of 2022-07-04 and can be observed with GOES-West (GOES-17) satellite imagery on RealEarth. The fire produced pyrocumulonimbus clouds, or pyroCb, which are storm clouds that start due to fire conditions.

As of 2022-07-05 at 15:00 UTC, the Electra Fire is 0% contained and has affected 3,034 acres.

Five-minute imagery video of GOES-17 Band 2 (visible) overlayed with Band 7 (infrared) showing the Electra Fire in northern California from 2022-07-04 22:30UTC to 2022-07-05 3:30UTC. The Band 7 “enhanced fire” signature can be seen beginning at 23:00UTC. This animation can be recreated using RealEarth.
A quick loop of GOES-17 true color imagery over the area, from 2022-07-04 22:20UTC to 2022-07-05 3:50UTC. The Electra Fire event is indicated by a red arrow. This animation was made using CSPP geo2grid.