CIMSS Satellite Blog

Pyrocumulonimbus cloud in Canada’s Northwest Territories

June 24th, 2022 | Scott Bachmeier

GOES-18 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.35 µm, bottom) images, which include hourly plots of surface reports [click to play animated GIF | MP4]

GOES-18 images in this blog post are preliminary and non-operational

GOES-18 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a small pyrocumulonimbus (pyroCb) cloud — generated by a wildfire that was burning near the northwest coast of Great Slave Lake in the Northwest Territories of Canada — on 24 June 2022. The pyroCB cloud then drifted southeastward across the lake, toward Resolute Bay (CYFR). Incidentally, this was Canada’s first documented pyroCb of the 2022 wildfire season.

Suomi-NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images valid at 1930 UTC, with plots of surface reports [click to enlarge]

Suomi-NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images valid at 1930 UTC (above) showed the pyroCb shortly after it formed (when it exhibited a minimum cloud-top 11.45 µm infrared brightness temperature of -49C, lighter shades of red) — and Suomi-NPP VIIRS images valid at 1930 UTC (below) displayed the pyroCb over Great Slave Lake at 2110 UTC (when it exhibited a minimum cloud-top 11.45 µm infrared brightness temperature of -54C, darker shades of violet).

Suomi-NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images valid at 2110 UTC, with plots of surface reports [click to enlarge

Posted in Fire detection, GOES-18, Suomi NPP, VIIRS | Comments Off on Pyrocumulonimbus cloud in Canada’s Northwest Territories

30-second GOES-17 images over Utah and Colorado

June 23rd, 2022 | Scott Bachmeier

GOES-17 “Red” Visible (0.64 µm) images, with plots of hourly surface reports [click to play animated GIF | MP4]

The radar at NWS Grand Junction, Colorado (KGJT) was down for scheduled maintenance in late June 2022 — and on 23 June, overlapping 1-minute Mesoscale Domain Sectors provided 30-second GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above), which showed the development of thunderstorms across a portion of their County Warning Area (which includes eastern Utah and western Colorado) to help fill their gap in radar coverage. These particular storms did not reach severe levels, but some produced small hail, strong winds and heavy rainfall (Local Storm Reports).

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Alaskan wildfire smoke

June 22nd, 2022 | Scott Bachmeier

GOES-18 True Color RGB images [click to play animated GIF | MP4]

GOES-18 images in this blog post are preliminary and non-operational

GOES-18 True Color RGB images created using Geo2Grid (above) showed smoke from Alaskan wildfires that had been transported southward over Kodiak Island and the northern Gulf of Alaska. Most of this smoke remained aloft — note that although Kodiak began reporting smoke late in the day, the surface visibility remained at 10 miles (below).

Plot of surface report data from Kodiak, Alaska [click to enlarge]

A composite of VIIRS True Color imagery (below) showed the location of active fires over Alaska on that day.

Composite of VIIRS True Color imagery, with fire thermal signatures shown in red [click to enlarge]

Posted in GOES-18, Red-Green-Blue (RGB) images, VIIRS | Comments Off on Alaskan wildfire smoke

Cross-sections using gridded NUCAPS data in AWIPS

June 21st, 2022 | Scott Lindstrom

NOAA-20 Day Night Band visible imagery (0.70) along with NUCAPS Sounding Availability points, ca. 19z on 21 June 2022 (Click to enlarge)

Gridded NUCAPS data, available from NOAA-20 data within AWIPS, can be used to construct cross-sections in AWIPS. The image above includes an editable baseline J-J’ (one of 10 different lines that can be used for data in AWIPS) from Minnesota into Indiana, roughly perpendicular to a line of broken cumulus over Wisconsin and Iowa.

Equivalent Potential Temperature along line J-J’ as indicated in imagery above (Click to enlarge)

The cross section of equivalent potential temperature, above, shows very warm temperatures over the southern portions of the cross section, with theta-e values around 350 K. Potential Instability, i.e., theta-e values decreasing with height, is widespread along the cross-section. The broken cloud field in the VIIRS imagery on top eventually did initiate convection, as shown in this radar capture from 0012 UTC on 22 June.

How do you create the cross-sections in AWIPS? Use the Volume Browser, as shown in the screen capture below. Select ‘Cross Section’ (vs. ‘Plan view’, for example) from the choices in the Volume Browser right next to ‘File’, ‘Edit’ and ‘Tools’, then choose ‘GriddedNUCAPS’ under ‘Sources’, and choose the correct Plane — as one of the Specified Lines you have previously moved in AWIPS; then choose the variable (possibilities are shown in the image; I chose Equiv Pot Temp).