Severe thunderstorms in Montana and South Dakota

June 28th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC storm reports plotted in red; Carter County, Montana and Harding County, South Dakota are outlined in blue [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed thunderstorms which produced large hail and tornadoes in far southeastern Montana and far northwestern South Dakota (SPC storm reports | NWS Billings | NWS Rapid City) on 28 June 2018. The pulsing nature of the parent storm’s overshooting tops was very apparent in the animation.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed cloud-top infrared brightness temperatures in the -70 to -75ºC range (black to light gray enhancement) associated with some of the overshooting tops (for example, at 0233 UTC).

GOES-16 "Clean" Infrared Window (10.3 µm) images, with SPC storm reports plotted in red; Carter County, Montana and Harding County, South Dakota are outlined in blue [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in red; Carter County, Montana and Harding County, South Dakota are outlined in blue [click to play MP4 animation]

These overshooting top infrared brightness temperatures were 5-10ºC colder than the -65.3ºC tropopause temperature on 00 UTC Rapid City SD rawinsonde data (below).

Plot of rawinsonde data from Rapid City SD [click to enlarge]

Plot of rawinsonde data from Rapid City SD [click to enlarge]

Derecho from the Midwest to the Mid-South

June 28th, 2018 |

GOES-16

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a large Mesoscale Convective System (MCS) which produced a long-lived path of large hail and damaging winds from eastern Nebraska to western Tennessee on 28 June 2018. The length and duration of damaging wind events (SPC storm reports) qualified this event as a derecho.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed cold cloud-top infrared brightness temperatures that occasionally reached -80ºC (violet enhancement).

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

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

A closer look at the MCS using 375-meter resolution Suomi NPP VIIRS Infrared Window (11.45 µm) images (below) showed cloud-top gravity waves on the 1844 UTC image, propagating radially outward from the primary area of overshooting tops; cloud-top infrared brightness temperatures were as cold as -86ºC (violet enhancement).

Suomi NPP VIIRS Infrared Window (11.45 µm) images, with SPC storm reports plotted during the 3 hours preceding the 1844 UTC image [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) images, with plots of SPC storm reports during the 3 hours preceding the 1844 UTC image [click to enlarge]

River valley fog in the Upper Midwest

June 28th, 2018 |

NOAA-20 VIIRS Day/Night Band (0.7 µm) and

NOAA-20 VIIRS Day/Night Band (0.7 µm) and “Fog Product” Infrared Brightness Temperature Difference (11.0 – 3.7 µm) images, with plots of Ceiling and Visibility [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and "Fog Product" Infrared Brightness Temperature Difference (11.0 - 3.7 µm) images, with plots of Ceiling and Visibility [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and “Fog Product” Infrared Brightness Temperature Difference (11.0 – 3.7 µm) images, with plots of Ceiling and Visibility [click to enlarge]

Comparisons of NOAA-20 and Suomi NPP VIIRS Day/Night Band (0.7 µm) and “Fog Product” Infrared Brightness Temperature Difference images (above) showed the nighttime formation of river valley fog in parts of the Mississippi River and its tributaries in Minnesota, Wisconsin and Iowa on 28 June 2018.  Due to ample illumination from the Full Moon, the Day/Night Band provided a “visible image at night” with better fog detail in some areas than was seen using the traditional “Fog Product”. (Note: the NOAA-20 images are incorrectly labeled as Suomi NPP)

A toggle between NOAA-20 and Suomi NPP VIIRS Day/Night Band images acquired by the SSEC Direct Broadcast ground station (below) revealed increased fog formation over portions of the Mississippi River between Rochester MN and Madison WI during the 52 minutes separating the two images.

NOAA-20 and Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

NOAA-20 and Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

During the subsequent daylight hours, GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (below) showed that the fog dissipated by 15 UTC or 10am local time.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface weather type [click to play animation | MP4]

GOES-16 Natural Color Red-Green-Blue (RGB) images are shown below.

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

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