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]

Pyrocumulonimbus cloud from the Spring Fire in southern Colorado

June 27th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the Spring Fire which began burning just west of La Veta Pass (station identifier KVTP) in south-central Colorado on 27 June 2018. The fire produced a small pyrocumulonimbus (pyroCb) cloud around 0100 UTC, which drifted slowly to the northeast. The 10.3 µm cloud-top infrared brightness temperature cooled below the -40ºC (lime green enhancement) pyroCb threshold.

===== 29 June Update =====

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

A nighttime comparison of NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images at 0852 UTC or 2:52 am MST on 29 June (above; courtesy of William Straka, CIMSS) showed the visible and thermal signatures of the Spring Fire. With ample illumination from the Moon (in the Waning Gibbous phase, at 98% of full), the hazy signature of smoke could be seen drifting northeastward past the Colorado/Kansas border.

Eruption of the Sierra Negra volcano in the Galapagos

June 26th, 2018 |

GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm), Mid-level Water Vapor (6.9 µm) and Low-level Water Vapor (7.3 µm) images beginning late in the day on 26 June 2018 (below) showed that a signature of the volcanic plume was evident in the 7.3 µm imagery for several hours after it was no longer seen in the 10.3 µm or 6.9 µm imagery — this is due to the fact that the 7.3 µm spectral band is also sensitive to SO2 absorption (and this volcanic eruption produced large amounts of SO2).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm, top), Mid-level Water Vapor (6.9 µm, middle) and Low-level Water Vapor (7.3 µm, bottom) images [click to play animation | MP4]

Severe thunderstorms in the Southeast US

June 25th, 2018 |

GOES-16

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

GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) showed the development of thunderstorms which produced small hail and widespread damaging winds (SPC storm reports) across the Southeast US on 25 June 2018.

A closer view of the storms was provided by GOES-16 “Red” Visible (0.64 µm) images (below).

GOES-16

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

A toggle between an 1854 UTC Aqua MODIS Infrared Window (11.0 µm) image and the corresponding Total Precipitable Water derived product (below) showed that abundant moisture was in place across the region — as pointed out by a SPC Mesoscale Discussion, TPW values in excess of 2.0 inches (50 mm, violet enhancement) suggested that wet microbursts were likely with any thunderstorms that developed.

Aqua MODIS Infrared Window (11.0 µm) image and Total Precipitable Water derived product, with plots of SPC storm reports [click to enlarge]

Aqua MODIS Infrared Window (11.0 µm) image and Total Precipitable Water derived product, with plots of SPC storm reports [click to enlarge]