Severe weather in Minnesota and Wisconsin

July 19th, 2019 |

GOES-16 "Red" Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play MP4 animation]

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development and propagation of a Mesoscale Convective System (MCS) that produced hail up to 3.0 inches in diameter in Minnesota and wind gusts to 84 mph and a few tornadoes in Wisconsin (SPC Storm Reports | NWS Twin Cities | MN DNR | NWS Green Bay) on 19 July 2019. Numerous overshooting tops and widespread storm-top gravity waves were evident in the imagery, along with a few Above-Anvil Cirrus Plume features extending northeastward from some of the overshooting tops around sunset. Also notable were the inflow feeder bands that were streaming northward into the southern flank of the MCS across Minnesota.

A comparison of GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (below) revealed cloud-top infrared brightness temperatures as cold as -86ºC over northwestern Wisconsin.

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play MP4 animation]

As the MCS persisted into the subsequent nighttime hours, GOES-16 Infrared images (below) showed the large canopy of cold cloud tops, with infrared brightness temperatures of -80ºC or colder (violet pixels).  Some of the embedded storms exhibited well-defined Enhanced-V storm top signatures (for example, at 2219 UTC).

GOES-16

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

===== 22 July Update =====

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

A comparison of Terra MODIS True Color Red-Green-Blue (RGB) images from 11 July and 22 July (above) showed the subtle NW-SE oriented swath of downed trees across northeastern Wisconsin. A 14 July vs 22 July comparison as viewed using RealEarth is shown below — the swath extended from approximately Pickerel to Mountain.

14 July and 22 July Terra MODIS True Color RGB images [click to enlarge]

Terra MODIS True Color RGB images, 14 July vs 22 July [click to enlarge]

In 22 July Terra MODIS images displayed using AWIPS (below), the swath of downed trees was brighter (more reflective) in the Near-Infrared “Snow/Ice” (1.61 µm), warmer (darker shades of orange to red) in the Shortwave Infrared (3.7 µm) and Land Surface Temperature, and lighter shades of green in the Normalized Difference Vegetation Index.

Terra MODIS Visible (0.65 µm), Near-Infrared "Snow/Ice" (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

Terra MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

The swath of downed trees was also seen in GOES-16 Normalized Difference Vegetation Index images (below), showing up as a darker shade of green with that product’s default enhancement.

GOES-16 Normalized Difference Vegetation Index images [click to play animation]

GOES-16 Normalized Difference Vegetation Index images on 22 July [click to play animation]

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