Severe weather in southeastern Wyoming and eastern Colorado

July 29th, 2018 |
Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play MP4 animation]

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right), with SPC storm reports plotted in red [click to play MP4 animation]

* GOES-17 images shown here are preliminary and non-operational *

A comparison of GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) Visible images (above) showed thunderstorms which produced tornadoes, large hail and damaging winds (SPC storm reports) from southeastern Wyoming to eastern Colorado on 29 July 2018. The images are displayed in the native projections of each satellite; images from GOES 16/17 are at 5-minute intervals, while those from GOES-15 are at intervals ranging from 4 to 30 minutes (depending on the operational scan schedule for that GOES-West satellite).

The first infrared images (NOAA/NESDIS News) from GOES-17 (below) also showed the development of these severe thunderstorms. The coldest cloud-top Infrared Window (11.2 µm) brightness temperatures over eastern Colorado were around -70ºC (dark black enhancement) after about 2200 UTC.

GOES-17 Infrared (11.2 µm) images [click to play animation | MP4]

GOES-17 Infrared (11.2 µm) images [click to play animation | MP4]

Images from all 16 spectral bands of the GOES-17 ABI are shown below. Prior to the development of convective storms, mountain waves could be seen over Wyoming and Colorado on Water Vapor bands 8 (6.17 µm), 9 (6.93 µm) and 10 (7.34 µm).

All 16 bands of the GOES-17 ABI [click to play animation | MP4]

Images from all 16 bands of the GOES-17 ABI [click to play animation | MP4]

Tornadoes in Wyoming

July 28th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface observations (cyan/yellow) along with SPC storm reports and Interstate Highways (red) and State Highways (cyan) [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development of a supercell thunderstorm that produced tornadoes, large hail and damaging winds (SPC storm reports) across parts of eastern Wyoming on 28 July 2018. A distinct above-anvil cirrus plume could be seen with this storm.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed that the dominant northern storm began to exhibit a well-defined “enhanced-V” signature (2051 UTC image) about an hour before it began to produce tornadoes. Minimum cloud-top infrared brightness temperatures were in the -60 to -65ºC range (darker shades of red) with the stronger pulses of overshooting tops.

GOES-16 "Clean" Infrared Window (10.3 µm) images, with hourly plots of surface observations (yellow) along with SPC storm reports (cyan) Interstate Highways (violet) and State Highways (cyan) [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly plots of surface observations (yellow) along with SPC storm reports (cyan) Interstate Highways (violet) and State Highways (cyan) [click to play MP4 animation]

A sequence of Infrared Window images from Suomi VIIRS (11.45 µm) and Aqua MODIS (11.0 µm) (below) showed minimum cloud-top infrared brightness temperatures rapidly cooling from the -40s to -72ºC as the dominant storm crossed Interstate 25.

Suomi NPP VIIRS and Aqua MODIS Infrared Window images [click to enlarge]

Infrared Window images from Suomi NPP VIIRS (11.45 µm) and Aqua MODIS (11.0 µm) [click to enlarge]

A comparison of the Terra and Aqua MODIS Total Precipitable Water product (below) indicated that TPW values increased from the 10-20 mm range to the 20-30 mm range in less than 2 hours.

Terra and Aqua MODIS Total Precipitable Water product [click to enlarge]

Terra and Aqua MODIS Total Precipitable Water product [click to enlarge]

Large hail and high winds in South Dakota and Nebraska

July 27th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

A supercell thunderstorm which developed in southeastern Montana during the afternoon hours on 27 July 2018 produced damaging wind-driven hail as it moved southeastward across western South Dakota into far northern Nebraska (SPC storm reports | NWS Rapid City summary). 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the evolution of this storm.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed minimum cloud-top infrared brightness temperatures in the -60 to -70ºC range (darker red to black enhancement) with the strongest pulses of overshooting tops. The storm began to exhibit a well-defined “enhanced-V” signature once it crossed the South Dakota / Nebraska border after about 0200 UTC.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in purple [click to play MP4 animation]

 


===== 30 July Update =====

Terra MODIS True Color and False Color RGB images [click to enlarge]

Terra MODIS True Color and False Color RGB images, with hail damage swath highlighted by red arrows [click to enlarge]

A comparison of 250-meter resolution Terra MODIS True Color and False Color Red-Green-Blue (RGB) images from the MODIS Today site (above) showed the northwest-to-southeast hail damage swath across southwestern South Dakota on 30 July.

Before/after (16/30 July) comparisons of MODIS True Color RGB images viewed using RealEarth and MODIS Today (below) further illustrate the appearance of the hail damage swath.

MODIS True Color RGB images from 16 July and 30 July [click to enlarge]

Terra MODIS True Color RGB images from 16 July and 30 July [click to enlarge]

Terra MODIS True Color RGB images from 16 and 30 July [click to enlarge]

Terra MODIS True Color RGB images from 16 July and 30 July [click to enlarge]

In a comparison between the 30 July Terra MODIS Visible (0.65 µm) image and the corresponding Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) products (below), within the core of the hail damage swath (near Oglala) LST values warmed into the 90s F and NDVI values were reduced to the 0.2 to 0.3 range (compared to cooler LST values in the 80s F and higher NDVI values of 0.3 to 0.6 over healthy vegetation areas immediately adjacent to the damage swath).

Terra MODIS Visible (0.65 µm) image and Land Surface Temperature and Normalized Difference Vegetation Index products [click to enlarge]

Terra MODIS Visible (0.65 µm) image and Land Surface Temperature and Normalized Difference Vegetation Index products [click to enlarge]

===== 31 July Update =====

MODIS True Color RGB images from Terra (14 July) and Aqua (31 July) [click to enlarge]

MODIS True Color RGB images from Terra (14 July) and Aqua (31 July) [click to enlarge]

In a better, more cloud-free before/after comparison of MODIS True Color images from 14 and 31 July (above), it can be seen that the NW-SE oriented hail damage swath extended into Nebraska (where hail as large as 3.0 inches was reported).

Severe thunderstorms in southwest Missouri

July 19th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm), with hourly surface plots plotted in cyan/yellow and SPC storm reports plotted in red [click to play MP4 animation | Animated GIF]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the rapid intensification of thunderstorms over far southwestern Missouri during the early evening hours on 19 July 2018. Surface outflow boundaries from these storms produced damaging winds (SPC storm reports), including gusts to 45 knots (52 mph) at Branson West at 2355 UTC (text) and 55 knots (63 mph) at Branson (plot | text) at 0025 UTC — and strong winds capsized a boat on Table Rock Lake (located about midway between Branson West Airport KFWB and Branson Airport KBBG, map), resulting in 17 fatalities.

The overshooting tops of these intensifying storms began to penetrate the anvil debris of pre-existing convection after about 2330 UTC in the Monett KHFJ area, with an above-anvil cirrus plume becoming evident after 0000 UTC. The 0025 UTC image showed yet another new cell which had recently developed immediately northeast of Branson; its overshooting tops began rapidly penetrating the anvil debris of the aforementioned storms at 0018 UTC.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed cloud-top infrared brightness temperatures cooling to the -75 to -79ºC range (shades of light gray to white) with these thunderstorms, significantly colder than the -68.5ºC tropopause temperature on the 00 UTC Springfield MO rawinsonde report (plot | text).

GOES-16 "Clean" Infrared Window (10.3 µm), with hourly surface plots plotted in cyan/yellow and SPC storm reports plotted in dark blue [click to play MP4 animation | Animated GIF]

GOES-16 “Clean” Infrared Window (10.3 µm), with hourly surface plots plotted in cyan/yellow and SPC storm reports plotted in purple [click to play MP4 animation | Animated GIF]