Alonsa, Manitoba EF-4 tornado

August 3rd, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface reports; yellow * denotes the town of Alonsa [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 thunderstorm which produced an EF-4 tornado near Alonsa, Manitoba during the early evening hours on 03 August 2018. The cell began to develop southwest of Alonsa around 0020 UTC, and as the thunderstorm matured a series of pulsing overshooting tops could be seen. The haziness evident in the Visible imagery was due to smoke from wildfires in the western US and Canada.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed that the coldest cloud-top infrared brightness temperature of around -70ºC occurred at 0123 UTC (just prior to the time of the tornado).

GOES-16 "Clean" Infrared Window (10.3 µm) images, with hourly plots of surface reports; black * denotes the town of Alonsa [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly plots of surface reports; black * denotes the town of Alonsa [click to play MP4 animation]



Severe thunderstorms in Arizona

August 2nd, 2018 |
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 animation | MP4]

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 animation | MP4]

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

GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) Visible images (above) showed the development of thunderstorms which produced hail and damaging winds (SPC storm reports) in the Phoenix, Arizona area on 02 August 2018. The images are displayed in the native projection of each satellite (no re-mapping). Due to a Full Disk scan, GOES-15 mages were only available every 30 minutes at the beginning of this particular time period; images from GOES-17 were every 5 minutes; a GOES-16 Mesoscale Domain Sector provided images at 1-minute intervals.

The strong thunderstorm winds also produced significant blowing dust — winds gusted to 47 knots (54 mph) and visibility was reduced to 1/2 mile at Phoenix KPHX (below). Winds gusted to 53 knots (61 mph) and visibility fell to 1/4 mile at Chandler KCHD.

Time series of surface observations for Phoenix, Arizona [click to enlarge]

Time series of surface observations for Phoenix, Arizona [click to enlarge]



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]