As an anomalously-deep middle-tropospheric low migrated eastward over the Southwest US, severe thunderstorms developed ahead of a surface low and its associated cold front (surface analyses) as they moved from New Mexico into Texas on 13 March 2021 — as shown in 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) (above) and “Clean” Infrared Window (10.35 um) images (below). According to SPC Storm Reports, over a dozen tornadoes occurred (maximum intensity EF2), with hail as large as 2.5 inches in diameter and wind gusts as high as 87 mph.

South of the surface low, strong winds over the mountains of northern Mexico generated a significant amount of blowing dust (from deserts and dry lake beds), as seen in GOES-16 True Color RGB images created using Geo2Grid (above). This dust was then transported northeastward and eastward over parts of New Mexico and Texas, reducing the surface visibility at several sites. A pronounced dust signature (brighter shades of magenta) was also evident on GOES-16 Dust RGB images (below).

===== 14 March Update =====

Strong winds along the southern periphery of an intensifying winter storm over the central Rocky Mountains continued on 14 March — and GOES-16 True Color RGB images (above) showed another broad plume of blowing dust (along with a few narrow, brighter white smoke plumes from wildfires) that developed across northern Mexico, far southern New Mexico and western/southwestern Texas, which then moved northeastward during the day.

===== 15 March Update =====

GOES-16 Dust RGB images (above) indicated that a plume of dense airborne dust (brighter shades of magenta) which was initially transported northeastward across Texas on 14 March continued to move across Oklahoma during the subsequent overnight hours — where it appears to have merged with a patch of thickening clouds. These clouds continued to proceed northward across eastern Kansas and eventually passed over southeastern Nebraska and far northwestern Missouri, where there were reports of muddy residue from precipitation that had fallen upon vehicles:

Blowing dust from Texas + drizzle and light rain = muddy rain? pic.twitter.com/lZb8cLFsbH

— NWS Omaha (@NWSOmaha) March 15, 2021

This dust transport path was supported by HYSPLIT forward trajectories, initialized from a point centered on the dust plume in Texas (below).

In addition to the severe thunderstorms and strong winds / blowing dust discussed above, this complex and slow-moving system produced heavy snow in several states (WPC Storm Summary) — and a 2-day animation of GOES-16 Mid-level Water Vapor (6.9 µm) images covering the 13-15 March period (below) showed its large circulation.

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Clear skies over much of Alaska on 12 March meant that GOES-17 had a clear view of Denali.  The animation above, of GOES-17 CIMSS True Color imagery, shows the shadow of Denali (near the center of the imagery, due north of Cook Inlet) moving during the day.

A higher-resolution animation, below, using only the 0.64 µm visible imagery, from 1610 UTC on 12 March to 0240 UTC on 13 March 2021, also shows the changing of the shadow during the day.

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A potent winter storm is on tap for eastern Colorado (and surroundings) over the weekend.  As with any system bringing heavy snow, knowing the storm path is crucial.  From a recent Boulder WFO Forecast Discussion, available here:   “Recent models runs in the GFS and ECMWF have trended more to the north while the Canadian stays to the south.”  The toggles above and below compare NUCAPS satellite-based observations of tropopause pressure (NUCAPS at 1023 UTC above, at 0843 UTC below) with 40-km Rapid Refresh model estimates (1000 UTC above, 0900 UTC below) of the tropopause pressure.  Can you use the NUCAPS depiction of the tropopause to convince yourself that the model — the Rapid Refresh in this case — has the proper initialization/evolution of the impulse that will generate the snowfall?  (Note that the colormaps for all images are the same).

A challenge with this storm at this time is that the neither of the NOAA-20 NUCAPS fields available in AWIPS themselves sample the entirety of the tropopause fold.  One might use the 0844 UTC imagery above to conclude that the Rapid Refresh is too slow in the eastward progress of the storm.  It’s difficult to make the same conclusion from the 1026 UTC image, however, at top.  Ozone anomalies (shown below) from the NASA SPoRT gridded NUCAPS site (link) include the Suomi-NPP pass (in between the two NOAA-20 passes above) that does more completely sample the tropopause fold at one time;  however, those data are not available in the baseline AWIPS.  Perhaps the afternoon pass from NOAA-20 will offer better coverage.  (Update, below:  It did!)

Gridded Tropopause height fields and gridded ozone fields, shown below, do agree very well; use them interchangeably to identify tropopause folds.  The two fields are derived from different CrIS channels in NUCAPS.

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The 2000 UTC NOAA-20 overpass more completely sampled the upper tropospheric feature.  See below.  The placement of the feature in the Rapid Refresh looks approximately correct over the southwestern United States (that is, NUCAPS observations seem to overlap Rapid Refresh features);  there are some dissimilarities in features over the Dakotas:  farther north in NUCAPS, farther south in the Rapid Refresh.

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US Space Force EWS-G1 Infrared Window (10.7 µm) images (above) displayed the well-defined eye and eyewall structure of Cyclone Habana in the South Indian Ocean on 10 March 2021. This was the second period of Category 4 intensity (ADT | SATCON) during the life cycle of Habana.

Meteosat-8 Infrared images with contours of deep-layer wind shear from the CIMSS Tropical Cyclones site (below) showed that Habana was moving through an environment of relatively low shear.

Meteosat-8 Infrared images with an overlay of 1505 UTC Metop ASCAT winds (below) depicted a fairly uniform distribution of winds within the eyewall region, as Habana developed an annular structure.

SSMIS Microwave (85 GHz) images from DMSP-16 at 1139 UTC and DMSP-18 at 2327 UTC are shown below.

 

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