A GOES-17 airmass RGB, above, shows a strong feature in the Gulf of Alaska. It’s common to associate the orange and purple regions within that polar feature (that is accompanied by cloud features consistent with very cold air aloft) with enhanced ozone. What products are available online to gauge the amount of ozone?

The OMPS instrument on board NOAA-20 (and on Suomi-NPP) senses in the ultraviolet (from 250-310 nm) to compute ozone concentration. (For more information on OMPS, refer to this document) The figure below, taken from this Finnish website, shows ozone concentration for the 24 hours ending at 0110 UTC on 13 December. A distinct maximum is apparent over the Gulf of Alaska. Note the northern terminus of the observations that are related to the time of year: there is little Sun north of 60 N. The data for this were downloaded from the Direct Broadcast site at GINA at the University of Alaska-Fairbanks. OMPS data are also available (from Suomi-NPP) at NASA Worldview.

To determine the time of the data in the image below, consult the NOAA-20 orbital paths here. This image (from that site) shows a NOAA-20 ascending overpass between 2235 and 2245 UTC over the Gulf of Alaska.

NOAA-20 also carries the Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) instruments that are used to create NUCAPS vertical profiles; one of the trace gases retrieved in this way is ozone. The distribution of ozone (with values in regions where it was dark) from NUCAPS is shown below (from this website maintained by SPoRT), and it corresponds roughly with the OMPS estimates shown above.

Conclusion: The assumption that upper-tropospheric ozone values are large in regions where the airmass RGB is tinted red or purple is a good assumption, especially if other structures in the RGB — such as cumulus cloud development in the cold air — reinforce the idea that an intrusion of stratospheric air is occurring. The strong storm that this lowered tropopause is supporting is accompanied by a moist feed of air moving into central California, as shown below by MIMIC total precipitable water fields.

Gridded NUCAPS fields are being tested within RealEarth, as shown below. They should be generally available soon.

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LightningCast probabilities are part of the ProbSevere portfolio, and they are available in RealEarth (link). This machine-learning product relates Band 13 and Band 15 observations to the probability of lightning occurrence (in daytime, Band 2 and Band 5 are also used). When your blogger was awakened by thunder (at 0826 UTC), as cold rain fell on the roof, he naturally thought: “I wonder what LightningCast is doing?” The animation above shows probabilities increasing as lightning developed over southern Wisconsin. Initial lead time for lightning from the probabilities is not big — but probabilities do expand and encompass the region that is experiencing lightning. The time of the lightning did match the closest approach of the surface low, as shown in this 0900 UTC surface analysis.

That lightning was produced in near-freezing surface temperatures reflects the vigor of this extratropical system that spawned a deadly tornado outbreak over the mid-Mississippi River Valley and lower Ohio River Valley (SPC Storm Reports).

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GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images (above) include time-matched plots of SPC Storm Reports during a large outbreak of severe weather across parts of the Midwest and Southeast US from late in the day on 10 December to a few hours after midnight on 11 December 2021. The severe thunderstorms developed in advance of a strong cold front that was moving toward the Lower Mississippi Valley (surface analyses | VIIRS Infrared image). There were dozens of tornado-related deaths in 5 states — Kentucky, Arkansas, Tennessee, Missouri and Illinois — with most of those (at least 70) being in Kentucky. This event has become the deadliest December tornado outbreak in modern history.

Shown below is a closer look at the long-lived “Quad-State Supercell” thunderstorm that likely produced a  family of tornadoes that moved across northeast Arkansas, southeast Missouri, northwest Tennessee and western Kentucky. Note that a mesonet station 6 miles southwest of Mayfield, Kentucky reported a wind gust to 107 mph a few minutes before the tornado struck Mayfield — and after 0335 UTC, the Mayfield Airport (KM25) stopped providing data (presumably due to widespread tornado-related power outages). The pulsing of colder overshooting tops (highlighted by shades of white within black-enhanced cloud tops) was evident at the vertex of a prominent Enhanced-V signature — and this signature indicated that an Above-Anvil Cirrus Plume (reference | VISIT training) was likely present.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animated GIF | MP4]

For the fatal tornado that struck Mayfield, Kentucky this pulsing of overshooting tops during the time from Tornado Warning issuance (0305 UTC) to its arrival in Mayfield (around 0325 UTC) was seen in 1-minute GOES-16 Infrared images viewed using RealEarth (below).

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animated GIF | MP4]

In addition to the severe weather produced by this event, farther to the west strong westerly winds — ahead of a pair of advancing cold fronts — lofted multiple plumes of blowing dust, whose source regions were in New Mexico and Texas. GOES-16 True Color RGB images created using Geo2Grid (below) highlighted the tan-colored dust plumes (along with a couple of brighter white wildfire smoke plumes).    

GOES-16 True Color RGB images [click to play animated GIF | MP4]

GOES-16 Dust RGB mages (below) showed the eastward/northeastward transport of airborne dust (brighter shades of magenta) past sunset. At some locations, peak wind gusts were in the 50-60 knot range and surface visibility was reduced to 3 miles or less.

GOES-16 Dust RGB images [click to play animated GIF | MP4]

Additional information about this severe weather event is available from: NWS Little Rock AR | NWS Memphis | NWS Paducah KY | NWS Louisville KY.  

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Gridded GLM observations of Total Optical Energy, above, capture the tornado-producing long-lived storm that hit Mayfield KY (and others) on 10 December. This storm had its genesis in eastern Arkansas, and it moved northeastward through the bootheel of Missouri, then into western Kentucky. It was mostly isolated from a line of convection to its west until it approached Louisville at around 0600 UTC, when the cells began to join together.

GLM observations of Average Flash Area for the same time period are shown below.

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