1984: Carolinas Tornado Outbreak

March 29th, 2021 |

NOAA’s GOES-5 VISSR view of a historical outbreak in the Carolina’s in 1984. March 28th and 29th, 1984 saw one of the most destructive tornado events in the history of North and South Carolina.

Infrared Loop:

GOES-5 Infrared imagery from 12:00 UTC to 23:30 UTC on March 28, 1984.

The coldest clouds appear as darker shades of red. A regional scale IR loop.

Visible Loop:

GOES-5 visible imagery from 12:00 UTC to 23:30 UTC on March 28, 1984.

A more zoomed-in visible loop over the same time range.

H/T Melissa Griffin for reminding us of this case:

More background on this case in 1984 was posted by the NWS Willmington office: https://www.weather.gov/ilm/CarolinasOutbreak.

A combined visible and infrared GOES-5 Full Disk image from March 28, 1984 at 21 UTC.

A larger Full Disk “sandwich” image.

NOAA GOES-5 data are via the University of Wisconsin-Madison SSEC Satellite Data Services.

Satellite signature of the Falcon 9 re-entry

March 26th, 2021 |

GOES-17 Band 7 (3.9 µm) imagery at 03:58:27, 03:59:27 and 04:00:27 on 26 March 2021 (Click to enlarge)

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.


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.

GOES-17 ABI Band 3.9 µm imagery (Mesoscale Sector 1) at 0358 UTC (top), 0359 UTC (middle) and 0400 UTC (bottom) (click to enlarge)

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.

Geostationary satellite views of the most rain over 72-hours in 2007

February 27th, 2021 |

The record for the most rain over a 72-hour period was in late February 2007, with 3.930m (154.72″)! This was on Reunion Island, associated with Tropical Cyclone Gamede in South Indian Ocean. The island is east of Madagascar. This island also holds the record for the most rain (4,869 mm (191.7 in)) over a 96-hour period, associated with the same event. More on this case can be found in this 2009 BAMS article.

Meteosat-8

While the view of the cyclone from EUMETSAT‘s MET-8 was on the edge of the viewing area, the infrared window loop was still impressive.

A 3-day color-enhanced infrared window loop from EUMETSAT’s Meteosat-8 geostationary imager.

A longer loops of 3 and 4 days were also generated. Which shows Tropical Cyclone Favio as well. For these images, the coldest brightness temperatures have the green/yellow/red/pink colors. A one-day loop (February 25, 2007) in both mp4 and animated gif formats.

Meteosat-7

EUMETSAT’s Meteosat-7, due to its location over the Indian Ocean, had a more direct view of these cyclones.

A 3-day color-enhanced infrared window loop from EUMETSAT’s Meteosat-7 geostationary imager.

Note that the view angle is improved over Meteosat-8, but the image frequency is reduced. A longer Meteosat-7 loop was also generated. Again, Tropical Cyclone Favio can be seen.

A loop of Meteosat-7 visible band from February 25, 2007.

Visible loops (mp4 format) from February 23 and 24 and 26, 2007. The same loops as animated gifs: February 23, 24, 25 and 26, 2007.

H/T

Thanks to @Weather_History for the post on this event.

The above satellite data are from EUMETSAT, accessed via the University of Wisconsin-Madison Space Science and Engineering Center (SSEC) Data Services. The images were generated with McIDAS-X. More on EUMETSAT’s Meteosat Third Generation will appear in the Bulletin of the AMS.

NUCAPS fields across an upper tropospheric front

January 20th, 2021 |

GOES-16 ABI Airmass RGB, Band 10 and Band 8 (7.34 µm and 6.19 µm, respectively), and GOES-16 Airmass RGB overlain with NUCAPS sounding availability plots, 0801 UTC oni 20 January 2021 (click to enlarge)

The AirMass RGB from GOES-16 at 0800 UTC on 20 January 2021 showed a distinct color change across central Missouri, from red to green.  The enhanced red coloring suggests a large difference in water vapor brightness temperatures.  The toggle above (including an image with NUCAPS* sounding points), shows structures in the water vapor imagery consistent with an upper tropospheric front.

Water Vapor and Airmass RGB imagery fields are useful because they be compared to model fields of the tropopause, and similarities in model fields and satellite imagery lend credence to the idea that the model initialization is accurate.  Compare the Airmass RGB and the Rapid Refresh mapping of the pressure on the 1.5 PVU surface below.  There is good spatial correlation between model and satellite fields.

GOES-16 Airmass RGB and Rapid Refresh model field of Pressure on the 1.5 PVU surface, 0800 UTC 20 January 2021 (Click to enlarge)

How do vertical profiles from NUCAPS vary across the tropopause fold?  The animation below shows six different profile in Missouri and Arkansas, spanning the reddish region of the airmass RGB.

GOES-16 Airmass RGB image with selected NUCAPS profiles, as indicated. (Click to enlarge)

A more efficient way to view information from NUCAPS is to view gridded fields.  Polar2Grid is used to transform the vertical profile to horizontal fields at the individual NUCAPS pressure levels (and then vertical interpolation moves those fields to standard levels).  The animations below show gridded values that are all in agreement with the presence of a tropopause fold where the Airmass RGB and model fields suggest.  Gridded temperature and moisture can be combined in many ways.  Gridded Ozone is also available in AWIPS (some of these fields were created using the Product Browser).

Ozone from NUCAPS, below, does show an enhancement, as expected, in the region where the tropopause fold is suggested by the airmass RGB.

NUCAPS-derived ozone anomalies, ca. 0800 UTC on 20 January 2021 (Click to enlarge)

The gridded NUCAPS tropopause level, shown below, can also be inferred from the individual profiles shown above.

Gridded NUCAPS Tropopause level, ca. 0800 UTC on 20 January 2021 (click to enlarge)

Note how the lapse rates show relatively less stable air (in the mid-troposphere) in the region of the tropopause fold.

Gridded 500-700 mb Lapse rates, ca. 0800 UTC on 20 January 2021 (click to enlarge)

Mixing ratio shows dry mid- and upper-tropospheric air, in the region of the tropopause fold, as might be expected from the GOES-16 water vapor imagery.

Gridded NUCAPS esimates of 300-700 mb mixing ratio, ca. 0800 UTC on 20 January 2021 (Click to enlarge)

In general, NUCAPS data can be used to augment other satellite and model data to better understand the thermodynamic structure of the atmosphere.  For more information on NUCAPS profiles, refer to this training video.

*The careful reader will note that the timestamp of the NUCAPS Sounding Availability plot, 0753 UTC, is different from the GOES-16 imagery.  Why?  The NUCAPS Sounding Availability plot is timestamped (approximately) when NOAA-20 initially overflies North American airspace.  NOAA-20 was flying over Missouri shortly after 0800 UTC, as shown in this plot (from this website).  Gridded NUCAPS fields are timestamped when NOAA-20 is overhead.