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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GOES-17 (GOES-West) True Color RGB images created using Geo2Grid (above) showed a widespread pall of smoke covering much of southern Alaska — from above-normal fire activity during the preceding several days, amid drought conditions — along with the growth of new smoke plumes from many of the larger fires later in the day on 29 Jun 2022. This dense smoke was restricting the surface visibility at numerous sites, creating hazards to aviation and poor air quality for inhabitants. 

https://twitter.com/AlaskaWx/status/1542320792301490181

https://twitter.com/AlaskaWx/status/1542532881896972289

===== 30 June Update =====

On the following day, GOES-17 True Color RGB images (above) showed an increasing trend in the areal coverage of smoke — and also revealed the marked re-intensification of a 40-50 mile long line of the combined Koktuli River and Pike Creek fires in southwestern Alaska (northwest of Iiamna Lake).

A closer view of the Koktuli River and Pike Creek fire line is shown below, using 1-minute Mesoscale Sector GOES-17 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Day Cloud Land Fire RGB and Fire Temperature RGB images. This was reportedly the largest wildfire complex in that area of Alaska in the past 70 years.

The dense smoke plume was transported northwestward toward the Seward Peninsula, where it contributed to very poor air quality in Nome on the following day. 

https://twitter.com/AlaskaWx/status/1542890628710682625

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