Rapid convective development over Illinois and Wisconsin

June 14th, 2017 |

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in white and SPC storm reports plotted in cyan [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in white and SPC storm reports plotted in cyan [click to play MP4 animation]

** GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing **

1-minute interval Mesoscale Sector GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (above) showed the rapid development of convection across northern Illinois and southern Wisconsin on 14 June 2017. SPC storm reports indicated that these storms produced widespread hail, damaging winds and a few tornadoes.

GOES-16 Visible (0.64 µm) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm) images [click to play MP4 animation]

Closer views centered along the Wisconsin/Illinois border with Visible (0.64 µm) imagery (above) showed the overshooting tops associated with these thunderstorms, while the Snow/Ice (1.61 µm) imagery (below) helped to discriminate between higher-altitude glaciated cloud tops (darker gray) and lower-level cloud tops composed of supercooled water droplets (brighter white).

GOES-16 Snow/Ice (1.61 µm) images [click to play MP4 animation]

GOES-16 Snow/Ice (1.61 µm) images [click to play MP4 animation]

The animation of Visible and color-enhanced Infrared imagery at the top of this blog post shows pockets of very cold cloud top temperatures within the cirrus canopy above the developing convection. These generally indicate overshooting tops, at the top of very strong updrafts. In contrast, the Shortwave Infrared (3.9 µm) animation, below, shows relatively warm pixels that are darker in the grey-scale enhancement in about the same region. Why the difference? Ice crystals that emerge from the top of a strong updraft are very effective reflectors of solar radiation at a wavelength of 3.9 µm. The satellite detects both terrestrial 3.9 µm energy emitted from the cold cloud top and solar 3.9 µm energy reflected off the cloud top. The amount detected will be largest (and a warmer temperature is inferred) where ice crystals are smallest and most reflective: at the top of very strong updrafts. Very little solar 10.3 µm radiation is reflected off clouds.

GOES-16 Shortwave Infrared (3.90 µm) images [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.90 µm) images [click to play MP4 animation]

All 16 bands on ABI can be used to monitor the development of the strong convection — in the case shown below over west-central Illinois for one hour, from 1900-2000 UTC. Click here for a very zoomed-in animation over one cell!

GOES-16 ABI for all 16 channels, 1900-1959 UTC on 14 June 2017 [click to play MP4 animation]

GOES-16 ABI images from all 16 bands, 1900-1959 UTC on 14 June 2017 [click to play MP4 animation]

Lake Superior lake breeze and marine stratus

June 14th, 2017 |

GOES-16 Visible (0.64 µm) images, with hourly surface reports [click to play animation]

GOES-16 Visible (0.64 µm) images, with hourly surface reports [click to play animation]

** GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing **

GOES-!6 Visible (0.64 µm) images (above) revealed the presence of a well-defined lake breeze boundary on 14 June 2017, which extended well inland from Lake Superior across northeastern Minnesota and northwestern Wisconsin. This shallow pool of lake-cooled air was acting to suppress the formation  of inland cumulus clouds and  maintain marine layer fog/stratus over the water and the adjacent coast  — both of which slowed the warming of surface air temperatures. For example, in northwestern Wisconsin, Hayward Sawyer County Airport (KHYR) reached an afternoon high temperature of 81º F, while not far to the northwest Duluth Sky Harbor Airport (KDYT) only reached an afternoon high of 52º F as fog and stratus shrouded the site and held temperatures in the 40s F much of the day. Note that a few bore-like wave structures were seen in the lake stratus.

A comparison of Suomi NPP VIIRS Visible (0.64 µm) imagery at 1803 UTC with RTMA surface winds at 18 UTC (below) showed the flow and cloud features associated with the lake breeze.

Suomi NPP VIIRS Visible (0.64 µm) image, with RTMA surface winds [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) image, with RTMA surface winds [click to enlarge]