Midwest Derecho

August 10th, 2020 |

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

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the eastward progression of a Mesoscale Convective System (MCS) that produced a long swath of damaging winds (SPC Storm Reports) or derecho from eastern Nebraska to Indiana on 10 August 2020. The highest measured wind gust was 112 mph in eastern Iowa at 1755 UTC.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

In a comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC (below), the higher spatial resolution of the VIIRS instrument detected infrared brightness temperatures as cold as -84ºC, compared to -76ºC with GOES-16 (the same color enhancement is applied to both images). The northwest parallax offset associated with GOES-16 imagery at this location was also evident.

Comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC [click to enlarge]

Comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC [click to enlarge]

GOES-16 Visible/Infrared Sandwich Red-Green-Blue (RGB) and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports, is shown below. The probability contours are produced from a deep-learning algorithm used to identify patterns in ABI and GLM imagery that correspond to intense convection. It is trained to highlight strong convection as humans would identify it. Work is ongoing to incorporate this storm-top information into NOAA/CIMSS ProbSevere.

GOES-16 Visible/Infrared Sandwich RGB and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports (credit: John Cintineo, CIMSS) [click to play animation | MP4]

GOES-16 Visible/Infrared Sandwich RGB and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports (credit: John Cintineo, CIMSS) [click to play animation | MP4]

A comparison of Terra MODIS True Color RGB images (source) from before (28 July) and after (11 August) the derecho (below) revealed very large swaths of wind-damaged crops (lighter shades of green) across Iowa. It is estimated that around 10 million acres of corn and soybean crops were flattened by the strong winds.

Comparison of before (28 July) / after (11 August) Terra MODIS True Color RGB images centered over Iowa [click to enlarge]

Comparison of before (28 July) / after (11 August) Terra MODIS True Color RGB images centered over Iowa [click to enlarge]

A toggle between VIIRS True Color RGB images from Suomi NPP and NOAA-20 visualized using RealEarth (below) also displayed the crop damage swath.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 -- with and without map labels [click to enlarge]

VIIRS True Color RGB images from Suomi NPP and NOAA-20 — with and without map labels [click to enlarge]

Shown below is a before/after (28 July/11 August) comparison of VIIRS Day/Night Band (DNB) imagery (source), where many of the areas across Iowa that suffered significant power outages — appearing darker (due to a lack of city lights) on the nighttime DNB images — corresponded to the large swaths of crop damage seen on the 11 August MODIS True Color image. Around 550,000 households lost power across the state.

VIIRS Day/Night Band (0.7 µm) images on 28 July and 11 August, along with a MODIS True Color RGB image on 11 August [click to enlarge]

VIIRS Day/Night Band (0.7 µm) images on 28 July and 11 August, along with a MODIS True Color RGB image on 11 August [click to enlarge]

Even 2 days later (on 12 August), many customers remained without power across Iowa (below), especially in Marshall County (where peak winds of 106 mph were recorded), Tama County (where peak winds of 90 mph were recorded) and Linn County (where peak winds of 112 mph were recorded).

Iowa counties with power outages on 12 August [click to enlarge]

Iowa counties with power outages on 12 August [click to enlarge]


Severe thunderstorms in Minnesota

August 8th, 2020 |

 GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed clusters of thunderstorms that developed along and just behind a cold front moving eastward across Minnesota on 08 August 2020. The northernmost hail-producing thunderstorm in Minnesota exhibited an Above-Anvil Cirrus Plume (reference | VISIT training); in addition, a decaying thunderstorm complex in southeastern North Dakota eventually revealed the cyclonic circulation associated with a Mesoscale Convective Vortex.

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

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

GOES-16 Visible images (above) and Infrared images (below) included time-matched SPC Storm Reports.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

A toggle between time-matched NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images (below) demonstrated the northwestward parallax displacement of GOES-16 cloud-top features (note: the same color enhancement enhancement has been applied to both images). Due to the 375-meter spatial resolution of VIIRS imagery, it was able to sense overshooting top infrared brightness temperatures as cold as -77.8ºC (compared to -65.7ºC with GOES-16). The higher resolution VIIRS image also provided a clearer depiction of the cloud-top gravity waves and tendrils of transverse banding.

NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images [click to enlarge]

NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images [click to enlarge]

A GOES-16 Infrared image with parallax displacement vectors and magnitudes (in km) from this site is shown below. For a 50,000 foot cloud top over southern Minnesota, the parallax adjustment was to the southeast at a distance of 21 km (13 miles) — this corresponded well to what was seen in the NOAA-20/GOES-16 comparison above.

GOES-16 Infrared image, with parallax displacement vectors (green) and magnitudes (red, in km) [click to enlarge]

GOES-16 Infrared image, with parallax displacement vectors (green) and magnitudes (red, in km) [click to enlarge]

Severe thunderstorms across the Upper Midwest

July 17th, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images, with and without an overlay of GLM Flash Extent Density [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images — with and without an overlay of GLM Flash Extent Density (above) — showed the development of a large Mesoscale Convective System (MCS) that developed over North Dakota and began moving eastward into Minnesota on 17 July 2020 (surface analyses). These thunderstorms produced a variety of severe weather, and heavy rainfall with up to 6 inches in North Dakota and 4 inches in Minnesota.

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

GOES-16 “Red” Visible (0.64 µm) images, with time-matched SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute GOES-16 Visible images (above) and Infrared images (below) include time-matched plots of SPC Storm Reports — of particular note was the wind gust of 101 mph (GOES-16 Visible / Infrared images) that occurred at a RAWS site in northeastern North Dakota around 2045 UTC, in the vicinity of a brief tornado. As the MCS continued to expand southward and eastward during the subsequent nighttime hours, it eventually produced damaging winds across northeastern South Dakota, much of Minnesota and northwestern Wisconsin.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

Animations of CIMSS Clear Sky Convective Available Potential Energy (CAPE), Lifted Index (LI) and Total Precipitable Water (TPW) products (below), from this site, showed the rapid destabilization and moisture increase of the air mass south and southeast of the developing MCS; this corridor of moist and unstable air was feeding northward, helping to sustain MCS growth and propagation.

CIMSS Clear Sky CAPE images [click to play animation]

CIMSS Clear Sky CAPE images [click to play animation]

CIMSS Clear Sky LI images [click to play animation]

CIMSS Clear Sky LI images [click to play animation]

CIMSS Clear Sky TPW images [click to play animation]

CIMSS Clear Sky TPW images [click to play animation]

These severe thunderstorms with tall cloud tops provided a good demonstration of the parallax shift inherent in GOES imagery at higher latitudes. Time-matched comparisons of Infrared images from NOAA-20 at 1933 UTC and Suomi NPP at 2023 UTC with the corresponding images from GOES-16 (below) showed that the GOES images were shifted northwest of the more accurate NOAA-20/Suomi NPP images.  The superior 375-meter spatial resolution of the VIIRS instrument allowed subtle cloud-top gravity waves to be seen — and the VIIRS cloud-top infrared brightness temperatures were about 10ºC colder than those sensed by the ABI instrument. The 1933 UTC images were about 15 minutes prior to the tornado and 101-mph wind gust at Churches Ferry (located about 20 miles northwest of Devils Lake KDVL).

Infrared Window images from NOAA-20 (11.45 µm) and GOES-16 (10.35 µm) at 1933 UTC [click to enlarge]

Infrared Window images from NOAA-20 (11.45 µm) and GOES-16 (10.35 µm) at 1933 UTC [click to enlarge]

Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 2023 UTC [click to enlarge]

Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 2023 UTC [click to enlarge]

An image showing parallax correction vectors and distance for a 50,00 ft (15.2 km) cloud top feature at various points within the GOES-16 CONUS domain (below) is from this site — and indicated a southeastward correction of about 28-30 km (or 17-19 miles) over northern North Dakota. This is in good agreement with what was seen in the 2 VIIRS/ABI infrared image comparisons shown above.

Parallax correction vectors (green) and distance (in km, red) for various points within the GOES-16 CONUS domain [click to enlarge]

Parallax correction vectors (green) and distance (in km, red) for a 50,00 ft (15.2 km) cloud top feature at various points within the GOES-16 CONUS domain [click to enlarge]

Severe thunderstorms across Iowa and Kansas

July 11th, 2020 |

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

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

Severe thunderstorms affected much of the Upper Midwest on 11 July 2020 — and 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed two separate clusters of thunderstorms that moved southeastward across Iowa, producing large hail and damaging winds (SPC Storm Reports). The initial round of storms produced a curved outflow boundary across central and eastern Iowa — and several orphan anvils could be seen forming along this outflow boundary before the second round of storms arrived. Numerous pulsing overshooting tops were evident within each of the storm clusters.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below. The coldest cloud-top infrared brightness temperatures were around -70ºC.

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

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

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

For the second round of storms that developed in far southern Minnesota during the early afternoon hours, GOES-16 Visible images (above) and Infrared images (below) include time-matched plots of SPC Storm Reports.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in violet [click to play animation | MP4]

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

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

Farther to the southwest, severe thunderstorms produced a north-to-south swath of large hail (up to 4.0 inches in diameter) and damaging winds across eastern Kansas (SPC Storm Reports). 1-minute GOES-16 Visible images (above) and Infrared images (below) showed these storms, whose pulsing overshooting tops eventually exhibited infrared brightness temperatures of -80ºC and colder (violet pixels).

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in violet [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in violet [click to play animation | MP4]