There are different RGBs available to monitor volcanic signatures within a cloud, and three common ones are shown above. The Dust RGB and the Ash RGB use identical channels/channel differences that are scaled differently. All three RGBs (here is the The SO₂ RGB Quick Guide) include Band 11 information; Band 11 detects radiation in the part of the electromagnetic spectrum that is sensitive to absorption by SO₂. For the Sheviluch eruption (described in blog posts here and here) that occurred just at the beginning of this animation above, the SO₂ signal — bright yellow in the SO₂ RGB — persists the longest. That, of course, will not be the case with every eruption; that’s why one must use more than one product to monitor an eruption.

Note that “Keep Out Zones” are apparent in the imagery above as regions of no data around 1440 UTC, when the Himawari-9 imager is turned off when it is pointing a little too closely towards the Sun.

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Himawari-9 imagery in this blog post are courtesy of JMA. The Full-Disk HSD data were processed into RGB images using geo2grid.

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By 14 April, much of the signal has shifted eastward out of Himawari-9’s field of view. The animation below, from GOES-18, shows the three RGBs from 0000 UTC on 14 April through 0000 UTC on 20 April. The signal of enhanced SO2 in particular has remarkable staying power.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) include plots of time-matched (+/- 3 minutes) SPC Storm Reports — which showed thunderstorms that produced hail as large as 4.50 inches in diameter and wind gusts to 63 mph across North Texas on 26 April 2023.  Cloud-top infrared brightness temperatures were as cold as -81ºC at 2328 UTC (violet pixels), and Above-Anvil Cirrus Plumes (reference | VISIT training) were evident with the 2 more dominant supercell thunderstorms.

1-minute GOES-16 Visible and Infrared images with/without an overlay of GLM Flash Extent Density (below) revealed that the easternmost supercell thunderstorm tended to exhibit a bit more lightning activity. These severe thunderstorms developed just to the north of a quasi-stationary frontal boundary that was draped across North Texas.

GOES-16 Visible and Infrared images at 0022 UTC (above) showed an Above-Anvil Cirrus Plume (AACP) particularly well — at that time there was a 20ºC infrared brightness temperature difference between the cold overshooting top (-76ºC, darker black enhancement) and the downwind AACP (-56ºC, brighter green enhancement). A warmer AACP was consistent with warming temperatures above the local tropopause, as seen in a plot of rawinsonde data (source) from Fort Worth, Texas at 0000 UTC (below).

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With Spring comes the beginning of fire season for the United States, and with the help of satellite data, model output can provide information about future smoke and fires.

Fire weather outlooks are available from the NOAA Storm Prediction Center (SPC). These are qualitative categorical outlooks similar to those the SPC issues for severe weather. Also provided by NOAA is the High-Resolution Rapid Refresh (HRRR) Smoke model, which forecasts smoke transport using a variety of inputs including radiances from GOES, MODIS, and VIIRS.

Both of these products are available in RealEarth, making it handy to gauge smoke and fire events across the United States and plan for future smoke and fire events. There are currently ‘elevated’ and ‘critical’ areas of New Mexico designated by the fire weather categorical outlooks. RealEarth is also available for Android and iOS.

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Due to the total solar eclipse over parts of the contiguous U.S. on April 8, 2024, there are many wondering what the cloud cover may be then.

Q: Will it be cloudy over the path of the total solar eclipse on April 8, 2024?

A: We don’t know what the cloud cover will be on April 8th, 2024. To offer a clue, we can look to the past. The animation below is a geostationary visible image from April 8 over the last few decades. One image (~19 UTC) is shown for each day. The satellites include: SMS-1, GOES-3, SMS-2, GOES-5, GOES-6, GOES-7, GOES-8, GOES-12, GOES-13 and GOES-16 (here is a timeline of the U.S. geo imagers). The loop below (animated gif and mp4) is also available as an animated gif and mp4 with a quicker playback speed. The expected eclipse path is over-plotted. In addition, here is an interactive path plot page.

Also see this interactive web page, where the speed of the loop can be changed, the image annotated, etc.

Another option is this cloud climatology by Brian Brettschneider:

366 days from today a total solar eclipse will move from southwest to northeast across the Contiguous U.S. This map show the climatological (historical) cloud coverage for April 8th during the middle of the day. [This is not a forecast.] ?? pic.twitter.com/y4a65ZDCx9

— Brian Brettschneider (@Climatologist49) April 8, 2023

Another cloud climatology, but from GOES.

Q: Will the NWS Weather Prediction Models include the total eclipse in their cloud forecasts?

A: We don’t know, but in 2017 certain experimental models did. Of course the cooling associated with the eclipse shadow can cause local changes to temperature, wind, cloud cover and other parameters.

Q: Is there a NOAA-operated sensor to provide rapid updates of cloud cover over the US?

A: Yes, there is a GOES constellation. There are many web sites (including the GOES Viewer) and phone apps to see realtime imagery.

Q: Isn’t there another solar eclipse coming up over the western U.S?

A: Yes, on October 14, 2023. Although that’s an annular (“ring“) eclipse, not a total eclipse. More, including the path.

Q: What might the moon’s shadow look like cast on the Earth during a total solar eclipse?

A: We have a good idea, based on previous cases from geostationary imagers, for example from 2017. Or see these other examples: 2019, 2020, 2020, 2021 and 2023 (2023).

Q: Can the cooling associated with a total solar eclipse affect the cloud patterns?

A: Yes it can, especially for “fair weather” cumulus. We saw from GOES the dissipation of certain clouds during the 2017 event (near St. Louis, MO).

Q: Should I look at the Sun without proper eye protection?

A: No.

Q: Is 99% close enough to experience the total eclipse?

A: No. Try to get into the region of totality.

H/T

These images were made using NASA and NOAA geostationary visible imagery with McIDAS-X software, from UW-Madison, SSEC. The images are via the SSEC Data Services. Thanks to Jim Nelson, Mat Gunshor, Scott Bachmeier and many others, including Kaba Bah. Thanks to Tom Whittaker for the java-script webapp (interactive web page). Thanks also for the Eclipse Predictions by Fred Espenak, NASA’s GSFC.

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