Large MCS affects Nebraska, Iowa, Kansas and Missouri

June 17th, 2017 |

GOES-16 Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play MP4 animation]

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

A large Mesoscale Convective System (MCS)  developed over eastern Nebraska late in the day on 16 June 2017, which continued  to grow in size as it  propagated southeastward  and produced severe weather across western Iowa, northeastern Kansas  and northwestern Missouri during  the subsequent overnight hours (SPC storm reports). GOES-16 Infrared Window (10.3 µm) images (above) include plots of time-matched  SPC storm reports;  the report locations are parallax-corrected to match those of the cloud tops. The strong winds downed  numerous trees and power lines;  Kansas City Power & Light reported  that as many as 93,000 customers — more than 10 percent — were without power within the utility’s service area (which covers 46 counties in Kansas and Missouri).

In a comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at  0721 UTC or 2:21 am local time on 17 June (below), the Day/Night Band image showed a bright cluster of lightning streaks (cloud tops illuminated by intense lightning activity) straddling the Kansas/Missouri border. Note how the city lights of the Kansas City area were almost completely attenuated by the dense and vertically thick MCS core, while a diffuse signature of city lights was seen through the thin cirrus canopy around the edges of the storm. Packets of cloud-top gravity waves evident on both images, and the coldest cloud-top Infrared brightness temperatures were -85º  C (darker violet color enhancement), located in both Kansas and Missouri.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11..45 µm) images, with cumulative plots of SPC storm reports [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11..45 µm) images, with cumulative plots of SPC storm reports [click to enlarge]

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]

Long-lived MCS tracks across South Dakota, Minnesota and Wisconsin

June 11th, 2017 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of hail and wind damage [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of hail and wind damage [click to enlarge]

A large Mesoscale Convective System (MCS) developed and intensified over western South Dakota during the nighttime hours of 10 June11 June 2017, evolving into a bow echo that spread a swath of hail and strong winds from central/eastern South Dakota across Minnesota and into Wisconsin and Michigan (SPC storm reports: 10 June | 11 June). Image toggles between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) at 0734 UTC or 2:34 am Central Time (above) and 0916 UTC or 4:16 am Central Time (below) showed numerous well-defined overshooting tops and cloud-top gravity waves over South Dakota. The coldest cloud-top infrared brightness temperature on the 0916 UTC image was -88º C (dark violet color enhancement). Since the Moon was in the Waning Gibbous phase (at 97% of Full), its ample illumination provided vivid examples of the “visible image at night” capability of the Day/Night Band; several bright white “lightning streaks” were also evident, a signature of cloud top illumination by intense lightning activity.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of hail and wind damage [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of hail and wind damage [click to enlarge]

During the subsequent daytime hours of 11 June, GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (below) showed the eastward  progression of the MCS across Minnesota into western Wisconsin.

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom), with SPC storm reports of hail and wind plotted in yellow [click to play animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom), with SPC storm reports of hail and wind plotted in yellow [click to play animation]

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