GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.3 µm) and Cloud Top Temperature product images displayed using AWIPS (above) showed the formation of a pyroCumulonimbus (pyroCb) cloud generated by the Delta Fire in Northern California late in the day on 05 September 2018. As the pyroCb cloud drifted eastward toward the California/Nevada border, Cloud Top Temperature values cooled to a minimum of -53ºC (lighter green enhancement) at 0300 UTC. Note the pulsing behavior of updrafts over the fire area: 2 distinct updraft pulses were apparent (at 0022 UTC and 0042 UTC), with the later pulse producing the pyroCb.

Massive plume of smoke over the #DeltaFire. ?: Jeff Mandrell pic.twitter.com/2QN66HcwM4

— Active NorCal (@ActiveNorCal) September 6, 2018

A longer animation of GOES-16 “Red” Visible, Shortwave Infrared and “Clean” Infrared Window images displayed using McIDAS (below) showed that the first hot (red) Shortwave Infrared pixels appeared at 2027 UTC. The fire caused a 5-mile section of Interstate 5 to be closed.

GOES-17 (positioned at 89.5º W longitude during its post-launch checkout phase) had a more direct view of the pyroCb than GOES-16 (positioned over the Atlantic Ocean at 75.2º W longitude) — and GOES-17 “Red” Visible, Shortwave Infrared and “Clean” Infrared Window images are shown below. Unfortunately the default GOES-17 Western US Mesoscale Domain Sector was shifted farther to the south on this day, so 1-minute imagery of the pyroCb event was not available.

* GOES-17 images shown here are preliminary and non-operational *

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GOES-17 Data shown here are preliminary and non-operational!

Stereoscopic views (using GOES-16 and — preliminary and non-operational — GOES-17 Visible (0.64 µm) imagery) of strengthening Tropical Storm Gordon are shown above. The stereoscopic view shows an initially sheared storm, with the surface circulation apparent becoming somewhat less sheared as convection redevelops over the surface center. (To view in three dimensions: cross your eyes until 3 equal images are apparent, and focus on the image in the center). This animation will be updated periodically as more GOES-17 data become available. (Click here for animated gif)

For more information on this storm, consult the National Hurricane Center website, or the CIMSS Tropical Weather Website.

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Potential Tropical Cyclone 7 was located between the Bahamas and Florida during the pre-sunrise hours on 03 September 2018. Toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 0636 UTC and Suomi NPP at 0726 UTC are shown above (courtesy of William Straka, CIMSS).

The storm became better organized and increased in intensity, and was named Tropical Storm Gordon at 1205 UTC. Animations of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) (below) showed Gordon as it moved across far southern Florida (where heavy rain and flash flooding occurred) and into the Gulf of Mexico during the daytime hours.

===== 04 September Update =====

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed a series of widespread deep convective bursts within the northeast quadrant of the storm as it moved northeastward toward the Gulf Coast.

The GOES-16 Rainfall Rate/QPE product (below) indicated rainfall rates of 2-3 inches per hour were possible from this convection, peaking in the 3-4 inch per hour range just after 1300 UTC. However, Infrared cloud-top brightness temperatures warmed dramatically as the convection moved onshore after about 22 UTC — and the Rain Rate product responded accordingly, with a significant decrease in hourly intensity.

Metop-A ASCAT surface scatterometer winds of 39 knots were sampled just northeast of the storm center at 1616  UTC (below).

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* GOES-17 images shown here are preliminary and non-operational *

1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) images (above) showed the dissipation of fog and stratus across the San Francisco Bay area on 03 September 2018. However, as most of the fog/stratus dissipated or retreated westward toward the coast in response to daytime heating, a persistent narrow ribbon of cloud was seen flowing east-northeastward through the Golden Gate and back into San Francisco Bay — with this flow of moist marine layer air leading to the formation of a new patch of low cloud as it encountered the higher terrain of the Berkeley Hills / San Pablo Ridge. This fog/stratus behavior was also observed using 1-minute GOES-14 Visible imagery in August 2016.

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