Variety of severe weather events hit central US - Aspot

Variety of severe weather events hit parts of the US

15 December 14:01-21:00 UTC

Variety of severe weather events hit central US - Aspot
Variety of severe weather events hit central US - Aspot

The passage of the low pressure wave over parts of America was accompanied by multiple extreme events in mid-December 2021.

Last Updated

17 December 2021

Published on

17 December 2021

By Ivan Smiljanic (CGI)

Multiple records were observed across affected states related to tornadoes, strong wind, dust, and even high temperatures in the far north.

Figure 1: GOES-16 ABI IR10.4 loop showing the cyclogenesis and wind rushing down the Rockies, 15 December 21:00 UTC (local afternoon)

Figure 1 shows the moment when the synoptic wave passed over the Rockies, behind which the lee cyclogenesis took place. Cold air behind the front rushed down the mountain, producing the 'winter haboob' (observe the thicker, mostly north--south oriented linear feature moving eastwards, from Denver onward), enhancing the dust lifting and pushing the squall line convergence (with associated tornado events), supporting also the wildfires in the south of the observed domain (Figure 2). The cyclone later moved towards the north-eastern states, pushing the warmth to the far north (record temperature anomalies).

GOES-16 solar channels comparison

Cloud Type RGB compare1
compare2
 

Figure 2: Features seen through GOES-16 ABI solar channels - comparison between Cloud Phase RGB and Cloud Type RGB, 15 December 21:00 UTC (local afternoon)

Strong synoptic dynamics were represented with abundance of red shades in Airmass RGB (associated to tropospause lowering, PV anomaly and cyclone deepening), while the strong magenta shades in Dust RGB confirm the thick and relatively high reaching dust clouds (Figure 3).

GOES-16 Airmass and Dust RGB comparison

Dust RGB compare1
compare2
 

Figure 3: Synoptic view on the associated cyclone dynamics through Airmass RGB (left), and strong dust signal in Dust RGB (right). GOES-16 ABI, 15 December 21:00 UTC (local afternoon)

Figure 4 shows the Dust RGB in motion, showing the moments when the synoptic wave passed the Rockies and when the strong wind started picking up the dust from the ground.

Figure 4: GOES-16 ABI Dust RGB in motion, 15 December 12:01-21:01 UTC

The so-called 'cirrus' channel also detected the dust cloud formation, mostly over Kansas (Figure 5). Due to the fact that this is a 'water vapour (WV) absorption channel', the brighter the dust cloud the higher it is (provided similar optical thickness). Aside from dust clouds, wave clouds behind the mountain range were nicely picked up with this NIR1.3 channel.

Figure 5: GOES-16 ABI NIR1.3 cirrus channel in motion, 15 December 14:01-23:56 UTC (daytime)

The best of both worlds is provided by the so-called 'sandwich product', a simple combination of Dust RGB and NIR1.3 imagery (Figure 6).

Figure 6: GOES-16 ABI Sandwich product (NIR1.3 channel and Dust RGB) in motion, 15 December 14:01-23:56 UTC (daytime)
 
 

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