Severe thunderstorms in Kansas and Oklahoma

June 23rd, 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 a number of Mesoscale Convective System (MCS) features across the southern Plains (with a focus on Kansas and Oklahoma) after sunset on 23 June 2018. A Mesoscale Domain Sector was positioned over that region, providing images at 1-minute intervals; SPC storm reports are plotted in cyan.

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0748 UTC or 2:48 am CDT (below) showed two MCS features — one with its core in north-central Oklahoma and another over eastern Oklahoma. Features exhibited by the northern storm included numerous bright lightning streaks on the Day/Night Band image, with one cluster located over an area of damaging wind reports. The minimum cloud-top infrared brightness temperature associated with this storm was -86ºC (violet enhancement). Over Kansas, packets of gravity waves could be seen on both images, propagating radially outward from the storm core along the cloud top. The combination of lightning and damaging winds (which downed power poles) led to power outages that lasted into the next evening (map | provider listing) across parts of Oklahoma.

With the MCS over eastern Oklahoma, a large cluster of bright lightning streaks was co-located with the overshooting top (which had a minimum cloud-top infrared brightness temperature of -80ºC) — and a distinct above-anvil cirrus plume could be seen flowing east-southeastward from the overshooting top.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of damaging winds plotted in cyan [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with SPC storm reports of damaging winds plotted in cyan [click to enlarge]

About 48 minutes later, a 0836 UTC overpass of the NOAA-20 satellite provided similar VIIRS Day/Night Band and Infrared Window images (below). However, in that relatively short amount of time the Moon had moved to a position low on the western horizon, providing much less illumination of the cloud tops for the Day/Night Band image. Another striking difference was the presence of long black or dark gray “post-saturation recovery streaks” downstream of bright clusters of lightning in north-central Oklahoma — as the VIIRS instrument scanned across-track (from northwest to southeast), the Day/Night Band optical detectors became saturated by the brightness of the intense lightning activity. The minimum cloud-top infrared brightness temperature in eastern Oklahoma was -86ºC.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Hurricane Aletta

June 7th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Tropical Storm Aletta was upgraded to Hurricane Aletta at 21 UTC on 07 June 2018. As was the case on 06 June, a GOES-16 Mesoscale Domain Sector centered over the tropical cyclone provided 1-minute data — and an eye eventually became apparent on  “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) imagery (above).

DMSP-15, DMSP-17 and GPM GMI Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed an increase in organization of the eye structure as the day progressed.

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

===== 08 June Update =====

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Aletta went through a period of rapid intensification (ADT | SATCON), reaching Category 4 status by 15 UTC on 08 June. 1-minute GOES-16 Infrared (10.3 µm) images (above) showed the eye becoming more well-defined during the pre-dawn hours.

After sunrise, GOES-16 Visible images (below) initially hinted at the presence of mesovortices within the eye of Aletta.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Aletta had been moving over relatively warm water and within an environment characterized by low values of deep-layer wind shear (below) — both  of which were favorable factors for intensification. An animation of the deep-layer wind shear over the East Pacific Ocean during 06-07 June is available here.

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Aletta peaked in intensity later in the day on 08 June (ADT | SATCON) — as pointed out by NHC “This is also consistent with GOES-16 measurements of increased inner-core lightning observed to be occurring to the east of the eastern eyewall, which some research suggests corresponds to a halting of the intensification process”. GOES-16 Infrared (10.3 µm) imagery with GLM Group Density counts are shown below.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) with GLM Group Density counts [click to play MP4 animation]

Heavy snow across southern Minnesota, northern Iowa and southern Wisconsin

April 18th, 2018 |

24-hour snowfall ending at 12 UTC on 19 April [click to enlarge]

24-hour snowfall ending at 12 UTC on 19 April [click to enlarge]

The map above shows a band of heavy snow that fell across southern Minnesota (as much as 11.0 inches), northern Iowa (as much as 12.0 inches) and southern Wisconsin (as much as 9.4 inches) on 18 April 2018.

Animations of 1-minute Mesoscale Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), “Clean” Infrared Window (10.3 µm) and “Low-level” Water Vapor (7.3 µm) images (below) showed the formation of convective elements and banding along the southern edge of the colder cloud shield — snowfall rates were enhanced when these convective features moved overhead, and thundersnow was noted at some locations in northern Iowa and southern Wisconsin.

GOES-16

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

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly surface weather type plotted in yellow [click to play MP4 animation]

GOES-16

GOES-16 “Low=level” Water Vapor (7.3 µm) images, with hourly surface weather type plotted in cyan [click to play MP4 animation]

In south-central Wisconsin, Madison (KMSN) received 7.2 inches of snowfall, which set a new record for daily snowfall (and helped to make April the snowiest month of the 2017/2018 winter seeason). In addition, the daily maximum temperature was only 33 ºF, which was a record low maximum for the date. Over the southwestern part of the city, a cluster of GOES-16 Geostationary Lightning Mapper (GLM) Groups was detected from 1918 to 1919 UTC (below; courtesy of Dave Santek, SSEC) — the GOES-16 Visible image at that time did display a textured cloud top appearance characteristic of embedded convection across southern Wisconsin.

GOES-16 GLM Groups [click to enlarge]

GOES-16 GLM Groups [click to enlarge]

===== 20 April Update =====

GOES-16 true-color (daytime) and Infrared Window (10.3 µm, nighttime) images [click to play MP4 animation]

GOES-16 natural-color RGB (daytime) and Infrared Window (10.3 µm, nighttime) images [click to play MP4 animation]

A fast animation of GOES-16 natural-color Red-Green-Blue (RGB) images (above) revealed the rapid rate of snow melt — especially on 19 April — along the southern edge of the snow cover (where lighter amounts of snow fell). The effect of the high late-April sun angle also played a role in the rapid snow melt.

GOES-16 GLM data now available in RealEarth™

July 21st, 2017 |

GOES-16 Infrared Window (103 µm) images, with GLM Group data points plotted as white dots [click to play animation]

GOES-16 Infrared Window (10.3 µm) images, with GLM Group data points plotted as white dots [click to play animation]

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

Real-time GOES-16 Geostationary Lightning Mapper (GLM) data are now available for viewing using RealEarth™ (real-time GLM link). An example from 21 July 2017 is shown above, for an isolated thunderstorm that developed during the afternoon hours along a residual convective outflow boundary — which was evident on an animation of “Red” Visible (0.64 µm) imagery — draped across eastern Iowa. This storm produced 1.0-inch diameter hail and damaging winds within 7-22 minutes after the 2200 UTC end of the animation (SPC storm reports).  Both the GOES-16 “Clean” Infrared Window (10.3 µm) images and the GLM Group (GLM Events clustered by proximity; see this blog post) data points were available at 1-minute intervals, since the region was within the domain of one of the Mesoscale Sectors.

Note that during the early portion of the animation, a number of GLM Group points were located south of the rapidly-expanding cold cloud top shield — GLM data are parallax-corrected, assuming a cloud-top height of 12.5 km. The 18 UTC tropopause height was 15.0 km on the 18 UTC sounding at Davenport, Iowa.