GOES-14 SRSOR: Dissipation of river valley fog

August 20th, 2014
GOES-14 0.63 µm visible channel images, at 15 vs 5 vs 1-minute intervals (click to play Animated GIF)

GOES-14 0.63 µm visible channel images, at 15 vs 5 vs 1-minute intervals (click to play Animated GIF)

The GOES-14 satellite was in Super Rapid Scan Operations for GOES-R (SRSOR) mode, providing images at 1-minute intervals over the central US on 20 August 2014; an animation of 0.63 µm visible channel images (Animated GIF | MP4 movie | YouTube) showed the dissipation of river valley fog that had formed during the previous night over the Mississippi River and adjacent portions of southwestern Wisconsin, southeastern Minnesota, and northeastern Iowa. The 3 panels show images every 15 minutes (today’s current routine schedule), every 5 minutes (available during Rapid Scan Operations), and every 1 minute (which will be available from the ABI instrument on the next-generation GOES-R satellite).

Along the Wisconsin River valley, fog restricted the surface visibility to 0.15 mile at Prairie Du Chien KPDC and Boscobel KOVS, and 0.25 mile at Lone Rock KLNR (images with map and station location overlays).

Can you use the VIIRS Day/Night Band to know where heavy rain is falling?

August 19th, 2014
Suomi NPP VIIRS Day/Night Band at 0659 UTC and 0838 UTC, 19 August 2014 (click to enlarge)

Suomi NPP VIIRS Day/Night Band at 0659 UTC and 0838 UTC, 19 August 2014 (click to enlarge)

The VIIRS Day/Night Band image toggle above shows nighttime cloud cover over southern Wisconsin associated with a line of deep convection; note how some city lights are not seen (Madison WI KMSN at 0659 UTC, and Milwaukee WI KMKE at 0838 UTC). There are several reasons this may have happened. For example, the convection could have knocked out power over a large region (this did not happen). Scattering associated with the thick convective clouds may have attenuated the city light so much that it could not be detected.

The toggle below of the corresponding VIIRS 11.45 µm Infrared imagery shows very cold cloud tops (-60º to -70º C, near the tropopause) over Madison at 0659 UTC (the observation at 0653 UTC at the Madison airport was Heavy Rain with a Thunderstorm) and over Milwaukee at 0838 UTC (when the Milwaukee airport was having Moderate Rain; they received a half-inch of rain between 0753 and 0853 UTC). The combination of the thick convective cloud and especially the heavy rain is very likely why city lights cannot be seen at certain times, as liquid water is an excellent absorber of visible light. This radar image (from this story) shows the areal extent of the heavy rain at 0745 UTC on 19 August.

Suomi NPP VIIRS 11.45 µm Infrared imagery  at 0659 UTC and 0838 UTC, 19 August 2014 (click to enlarge)

Suomi NPP VIIRS 11.45 µm Infrared imagery at 0659 UTC and 0838 UTC, 19 August 2014 (click to enlarge)

GOES-14 SRSOR: Tropical Storm Lowell in the East Pacific Ocean

August 19th, 2014
GOES-14 0.63 µm visible channel images (click to play Animated GIF)

GOES-14 0.63 µm visible channel images (click to play Animated GIF)

The GOES-14 satellite was in Super Rapid Scan Operations for GOES-R (SRSOR) mode, providing coverage of Tropical Storm Lowell in the East Pacific Ocean on 19 August 2014; an animation of 0.63 µm visible channel images (Animated GIF | MP4 movie file | YouTube) showed a gradual increase in the organization of a convective banding structure during the day. At 12 UTC Tropical Storm Lowell was located several hundred miles southwest of Baja California, with a center at 15.5º North latitude, 119.5º West longitude.

GOES-15 10.7 µm IR channel images with an overlay of Metop ASCAT surface scatterometer winds from the CIMSS Tropical Cyclones site (below) showed the the strongest winds (40.0-49.9 knots, yellow barbs) were in the southeastern quadrant of Lowell at 17:11 UTC.

GOES-15 10.7 µm IR images with Metop ASCAT surface scatterometer winds

GOES-15 10.7 µm IR images with Metop ASCAT surface scatterometer winds

A comparison of the 16 UTC GOES-15 10.7 µm IR channel image with the corresponding DMSP SSMIS 85 GHz microwave image (below) indicated that the highest rainfall rates were associated with the convective banding  (and coldest cloud tops) within the southern semicircle of the storm.

GOES-15 10.7 µm IR image and DMSP SSMIS 85 GHz microwave image

GOES-15 10.7 µm IR image and DMSP SSMIS 85 GHz microwave image

GOES-14 SRSOR: Mesoscale Convective Vortex in the Southern Mississippi Valley

August 18th, 2014
GOES-14 0.63 µm visible channel images (click to play animation)

GOES-14 0.63 µm visible channel images (click to play animation)

The GOES-14 satellite was in Super Rapid Scan Operations for GOES-R (SRSOR) mode providing 1-minute imagery over the eastern US on 18 August 2014. From the late morning into the afternoon hours, 0.63 µm visible channel images (above; click image to play animation; also available as an MP4 movie file or a YouTube video) revealed a large and well-defined mesoscale convective vortex (MCV) propagating eastward across northern Mississippi. This MCV was spawned from a thunderstorm which rapidly developed over far southwestern Arkansas during the preceding nighttime hours (beginning around 06:15 UTC: GOES-13 IR images).

A comparison of Suomi NPP VIIRS 11.45 µm IR channel images (below) showed the rapid growth of the parent thunderstorm from 07:18 UTC to 08:59 UTC. The coldest cloud-top IR brightness temperatures were -80º C.

Suomi NPP VIIRS 11.45 µm IR channel images

Suomi NPP VIIRS 11.45 µm IR channel images