GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images centered on Nashville (above) displayed multiple clusters of thunderstorms that moved across Tennessee during the 27 March – 28 March 2021. The coldest overshooting top infrared brightness temperatures were in the -70 to -79C range. Precipitation ended and clouds cleared as a cold front moved eastward across the state on 28 March.

Hourly images of the MIMIC TPW product (below) showed the northward surge of moisture from the Gulf of Mexico beginning early on 27 March, providing an environment conducive to heavy rainfall.

Plots of Nashville rawinsonde data from 00 UTC and 12 UTC on 27 March (above) and 28 March (below) illustrated the rapid increase in moisture on 27 March, followed by the gradual decease in the wake of the cold frontal passage.

 

Here are some of our highest rainfall reports from Saturday morning through this morning and a map of combined radar estimates and observed precip. https://t.co/H9DHgOxCZW pic.twitter.com/Hk8qMxcRc3

— NWS Nashville (@NWSNashville) March 28, 2021

Nashville has measured another 0.94″ of rain since midnight. This gives us a 2-day rainfall total of 6.69″. This surpasses the 6.68″ measured on September 13-14, 1979, and gives us our 2nd largest 2-day rainfall total in Nashville’s history, trailing only May 1-2, 2010 (13.57″).

— NWS Nashville (@NWSNashville) March 28, 2021

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CMORPH estimates of accumulated precipitation (available in RealEarth) are shown below, with 24-hour totals ending 23:59 on 27 March (left) and 28 March (right).  The darker purple region denotes totals of >100 mm in 24 hours.

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The Falcon 9 rocket that was launched on 4 March did not achieve orbit and re-entered the atmosphere on 26 March at just before 0400 UTC (Correction:  Falcon 9 achieved orbit.  What did not occur as planned was the 2nd stage de-orbit burn  The low orbit of the 2nd stage allowed it to re-enter on 26 March, and that is what GOES-17 detected.  Thanks to Mark — see his comment bel0w —  for the correction!)  GOES-17’s ABI detected the re-entry heat signature off the coast of Oregon, at the very edge of the Mesoscale Sector 1, at 03:59:27 on 26 March 2021, as shown above in the Band 7 (3.9 µm) images at 03:58:27, 03:59:27 and 04:00:27. The heat signature was also detectable in the Band 6 (2.2 µm) imagery.

Many thanks to Chris Schmidt, CIMSS, for finding this subtle signature in the imagery!  This tweet from Jonathan McDowell includes many ground-based video captures of the re-entry.

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The image below, from Tim Schmit (NOAA/STAR), shows the three band 7 (3.9 µm) images, color-enhanced and magnified.  A similar image for band 6 (2.2 µm) is here.

Scott Bachmeier created this 6-channel (Bands 2, 3, 4, 5, 6 and 7 at 0.64 µm, 0.86µm, 1.37 µm, 1.61 µm, 2.25 µm and 3.9 µm, respectively) 3-step animation centered on the re-entry time.

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1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.35 µm) images (below) include time-matched plots of SPC Storm Reports that were produced by a number of supercell thunderstorms that developed and moved across the Deep South and Mid-South on 25 March 2021. The highest concentration of tornadoes occurred in Alabama, including one that was responsible for multiple fatalities in Ohatchee around 1842 UTC.

In a time-matched comparison of Infrared images from Suomi NPP (overpass times) and GOES-16 at 1831 UTC (below), the coldest overshooting top infrared brightness temperature sensed by the VIIRS instrument on Suomi NPP was -78ºC, compared to -72ºC by the ABI  instrument on GOES-16. Note the small northward parallax displacement that is inherent with GOES-16 imagery over that region. The same color enhancement is applied to both images.

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EUMETSAT Meteosat-11 Ash Height retrievals from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed that an eruption of Mount Etna in Sicily, Italy on 24 March 2021 produced an ash cloud which rose to heights of 7-8 km (darker shade of green).

The corresponding Meteosat-11 Ash Loading images are shown below — ash loading appeared to be light to moderate within much of the volcanic cloud.

Ash Loading values retrieved using Suomi NPP VIIRS data at at 1200 UTC (below) were notably higher than those from Meteosat-11, given the higher spatial resolution and additional spectral band data available from the VIIRS instrument.

A toggle between VIIRS True Color RGB images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) revealed hues of tan to light brown within the volcanic plume, further supporting the presence of an elevated ash content.

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