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 -55^oC. Note that a parallax shift (to the south-southeast, towards the GOES-16 sub-satellite point at 0^o N, 75.2^o 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.

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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.

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

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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.

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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).

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.

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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.

OCFA’s Intel 12 on the #ElectraFire Amador County. Fire is mapped at 390 acres at 17:06 hours. pic.twitter.com/fVzbCJ0cMA

— FIRIS (@FIRIS) July 5, 2022

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From today’s inbox: This morning was interesting because I saw very little indication in the vis channel or microphysics RGBs to indicate fog was present over far SW Lower MI this morning. Any thoughts why? When fog is difficult to view in satellite imagery, as on 2 July 2022, it’s usually because the fog is very thin (but even a very thin fog can cause transportation issues). It might also be that thin cirrus is obscuring the satellite view of low-level fog. The animation above shows some indication of high cirrus (as purple features). Note however, that IFR Probability fields (on top) do highlight a region over southern lower Michigan near station KIRS (Kirsch, MI, near Sturgis). This is, however, after the station there started to report IFR conditions — but before a signal appeared in the Night Microphysics RGB. In cases when satellite detection might not identify fog, numerical prediction fields (such as those used in the computation of IFR Probability) can give a forecaster an earlier alert on the presence of fog.

The animation below, from the CIMSS CSPP Geosphere site, shows the region through sunrise. The low clouds burn off quickly after sunrise, reinforcing the idea that they were very thin.

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Thanks to TJ Turnage, WFO Grand Rapids, for the alert about this challenging case. When satellite detection isn’t working, webcams and surface observations still do. Some imagery in this post was created using the NOAA/TOWR-S Cloud instance of AWIPS.

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