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]



Transport of Saharan Air Layer dust across the Atlantic

August 3rd, 2018 |

GOES-16 Split Window (12.3 µm - 10.3 µm) Saharan Air Layer product [click to play MP4 animation]

GOES-16 Split Window (12.3 µm – 10.3 µm) Saharan Air Layer product [click to play MP4 animation]

The GOES-16 (GOES-East) Saharan Air Layer (SAL) infrared Split Window (12.3 µm – 10.3 µm) product (above) showed a large outbreak of SAL dust that emerged from the northwest coast of Africa on 30 July 2018, eventually moving over the Lesser Antilles and Puerto Rico late in the day on 03 August.

During daylight hours, the dust-laden SAL was also evident in GOES-16 Natural Color Red-Green-Blue (RGB) imagery (source) on 01, 02 and 03 August (below).

GOES-16 Natural Color RGB images [click to play MP4 animation]

GOES-16 Natural Color RGB images [click to play MP4 animation]

GOES-16 Split Window 10.3 µm - 12.3 µm) images [click to play animation | MP4]

GOES-16 Split Window (10.3 µm – 12.3 µm) images on 02 August [click to play animation | MP4]

The AWIPS version of GOES-16 Split Window (10.3 µm – 12.3 µm) imagery with a different color enhancement (above) showed the westward motion of the SAL dust (shades of cyan) on 02 August. The corresponding GOES-16 Dust Detection product (below) verified the presence of dust within the SAL plume. Since the Dust Detection product uses Visible and Near-Infrared bands, it is only available during daytime hours (and at solar zenith angles less than 60 degrees).

GOES-16 Dust derived product [click to play animation | MP4]

GOES-16 Dust Detection product on 02 August [click to play animation | MP4]

GOES-16 Split Window (10.3 µm - 12.3 µm) product [click to play animation | MP4]

GOES-16 Split Window (10.3 µm – 12.3 µm) product on 03 August [click to play animation | MP4]

GOES-16 Split Window (10.3 µm – 12.3 µm) imagery from 03 August (above) showed the continued westward motion of the SAL dust (shades of cyan). The corresponding GOES-16 Aerosol Optical Depth (AOD) product (below) provided a more quantitative measure of airborne dust. Like the Dust Detection product shown previously, the AOD product also uses Visible and Near-Infrared bands — so it too is only available during daytime hours (and at solar zenith angles less than 60 degrees). Additional information on GOES-R Aerosol Detection Products in AWIPS is available here and here.

GOES-16 Aerosol Optical Depth product [click to play animation | MP4]

GOES-16 Aerosol Optical Depth product on 03 August [click to play animation | MP4]

The 03 August GOES-16 imagery indicated that the leading edge of the SAL began to move over Puerto Rico late in the day. A comparison of morning and evening rawinsonde data from San Juan (below) revealed that the temperature inversion at the base of the SAL became more well-defined at 00 UTC on 04 August.

Plots of rawinsonde data from San Juan, Puerto Rico [click to enlarge]

Plots of rawinsonde data from San Juan, Puerto Rico [click to enlarge]