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]


Blowing dust off the coast of Namibia and South Africa

August 7th, 2020 |

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

A sequence of 3 VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP and NOAA-20 as visualized using RealEarth (above) showed plumes of blowing dust moving off the coast of Namibia and South Africa on 07 August 2020.

EUMETSAT Meteosat-11 Visible (0.6 µm) images (below) displayed the motion of the dust plumes during the daytime hours.

Meteosat-11 Visible (0.6 µm) images [click to play animation | MP4]

Meteosat-11 Visible (0.6 µm) images [click to play animation | MP4]

A plot of surface data from Luderitz, Namibia (station identifier FYLZ) is shown below; it indicated that winds gusted to 36 knots (41 mph) at 08 UTC.

Plot of surface data from Luderitz, Namibia [click to enlarge]

Plot of surface data from Luderitz, Namibia [click to enlarge]

H/T to Santiago Gassó for bringing this event to our attention.

Heavy rainfall across Interior Alaska

August 2nd, 2020 |

Topography + GOES-17 "Clean" Infrared Window (10.35 µm) images [click to play animation | MP4]

Topography + GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

An animation of Topography + GOES-17 (GOES-West) “Clean” Infrared Window (10.35 µm) images (above) showed a southward-moving band of clouds responsible for producing heavy rainfall across portions of Interior Alaska on 02 August 2020. Cloud-top infrared brightness temperatures were as cold as -58ºC (brighter shades of yellow).

GOES-17 “Red” Visible (0.64 µm) images are shown below.

GOES-17 "Red" Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Blended Total Precipitable Water (TPW) and Percent of Normal TPW images during the 01-02 August time period (below) portrayed TPW values as high as 1.5 inches just north of Lake Minchumina — which was >190% of the normal value for this location and time of year.

Blended TPW and Percent of Normal TPW images [click to play animation | MP4]

Blended TPW and Percent of Normal TPW images [click to play animation | MP4]

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) revealed cloud-top infrared brightness in the -60 to -65ºC range (darker shades of red) within this cloud band.

VIIRS Infrared Window (11.45 ) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]


1 week of volcanic cloud emission from Nishioshima

August 1st, 2020 |

Himawari-8 Ash RGB images, from 25 July to 01 August 2020 [click to play animation | MP4]

Himawari-8 Ash RGB images, from 25 July to 01 August 2020 [click to play animation | MP4]

JMA Himawari-8 Ash Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed the nearly continuous volcanic cloud emanating from Nishinoshima during the 1-week 25 July to 01 August period (faster animations are also available: gif | mp4). Brighter shades of pink in the Ash RGB images suggest a higher concentration of ash within the volcanic cloud. The direction of plume transport switched from northwesterly/westerly to southerly/southeasterly during this time, which is explained by the transition in wind direction within much of the troposphere as revealed by rawinsonde data from nearby Chichijima (below).

Plots of rawinsonde data from Chichijima [click to enlarge]

Plots of rawinsonde data from Chichijima [click to enlarge]

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

After the transition to southerly transport, VIIRS True Color RGB images from NOAA-20 and Suomi NPP as visualized using RealEarth (above), the surface visibility at Iwo Jima RJAW dropped to 4 miles on 01 August (below) as the hazy volcanic plume drifted across the area.

Time series plot of surface observation data from Iwo Jima [click to enlarge]

Time series plot of surface observation data from Iwo Jima [click to enlarge]