1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images with time-matched SPC Storm Reports (above) showed widespread thunderstorms that moved northward across the High Plains during the afternoon and evening hours on 20 May 2020. There were Above-Anvil Cirrus Plumes associated with many of these severe storms (VISIT training).

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

The overall spatial scale of this convective complex is also remarkable for Canada as it continues to migrate northwest.

All of this is via a very impressive late season -tilted trough spanning the Rockies. Convection will fuel sfc cyclogenesis downstream of the trough axis. https://t.co/mlE5XMApCJ pic.twitter.com/DzQBCXIt7b

— Philippe Papin (@pppapin) May 21, 2020

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Dam failures in central lower Michigan along the Tittabawassee River (one of the rivers in the Saginaw Bay basin) caused extensive flooding on 20 May 2020 in Midland County, including the city of Midland. Much of this region received between 4 and 5 inches of rain in the past week (analysis, from this site). The Tittabawassee River gauge at Midland (shown here, from this site), was projected to exceed its previous maximum by 4 feet (It ended up exceeding it by just over 1 foot).  The heavy rains have produced a notable silt plume into Saginaw Bay in the imagery above (a plume that is rotating cyclonically).

GOES-16’s Advanced Baseline Imager (ABI) has spatial and spectral resolution to identify flooded regions near Midland, as shown in the imagery above from 1521 UTC on 20 May.  Of special note are the dark pixels very close to Midland MI in the 0.86 µm imagery (shown here with a map)   Water is more reflective in the visible (0.64 µm) than in the near-infrared (0.86 µm) (Compare the darkness of Lake Huron in those two channels) so when areas are flooded, they acquire a darker reflectance value.  A more zoomed-in toggle, below, between Visible (0.64 µm) and 0.86 µm imagery highlights the reflectance differences near Midland where flooding is occurring.  Flooded regions are also apparent south of Saginaw, to the south and east of Midland County.

Real Earth includes Flood Products that are derived from ABI and from the VIIRS Instrument (the Visible-Infrared Imaging Radiometer Suite) on NOAA-20 and Suomi NPP. The ABI-only product, below, taken from that site, shows the regions of flooding.

This link (courtesy Tim Schmit, NOAA/CIMSS) compares Band 3 (0.86 µm) imagery from before and during the flood (13 and 20 May 2020).  VIIRS true-color imagery, below, processed at the Direct Broadcast antenna at CIMSS, also show the changes from 13 May to 20 May.

The Flood Areal Extent processed from VIIRS data is shown below.  Both ABI and VIIRS products are available via LDM feed (in addition to being available in Real Earth and in GeoNETCAST). The Project Website is here. Tim Schmit has created a slider between the ABI and VIIRS flood product here.

The National Weather Service in Detroit is issuing flood warnings for this event. Midland County is in their County Warning Area.

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Shane Hubbard at UW-Madison/CIMSS has created an arcGIS website that shows the areal extent of the flooding.  That site is here.  A screen capture is shown below.

Satellite detection of this event is also discussed here.

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The satellites Terra (launched in 1999) and Aqua (launched in 2002) both carry the Moderate-Resolution Imaging Spectroradiometer (MODIS) instrument, an imager with 26 channels at wavelengths that range from 0.41 µm to 14.1 µm. There are simple ways to create useful imagery with this historical data with Polar2Grid software that was developed at CIMSS as part of the Community Satellite Software Package (CSPP). This blog post will show you how to create imagery as shown above (0.86 µm, 1.62 µm and 1.38 µm) over Mt. Everest on 28 January 2004.  (Similar imagery from 29 January 2004:  0.86 µm, 1.62 µm, 1.38 µm, or toggles between 28/29 January at 0.86 µm, 1.62 µm and 1.38 µm)

The self-contained Polar2Grid software package can be downloaded from this link. (You may have to register your email address before accessing the site; registration is free). Once on the website, scroll down to find “Polar2Grid V2.3 Reprojection Software for Linux” (note that the version number will occasionally increment!) and download the gzipped tarfile. You should also download the documentation (it’s a pdf file) at that site. This will tell you what to do before you can successfully run the software: for example, the POLAR2GRID_HOME variable must be set:
export POLAR2GRID_HOME=/path/to/softwarebundle.

Next, order archived MODIS data. These data are available at the NASA LAADS (Level-1 and Atmosphere Archive and Distribution System) DAAC (Distributed Active Archive Center) at this link. If you click on ‘Find Data’ at that website, a long list of possible products will be displayed. MODIS data that are compatible with Polar2Grid are Level 1b Calibrated Radiances: MOD02 files, and for this example I chose 1-km and half-kilometer resolution (that is, MOD021KM, MOD02HKM). Geolocation files (MOD03) must also be selected.

Polar2Grid includes software to create a grid onto which the data will be projected; for the example above, I first ran the Polar2Grid script ./p2g_grid_helper.sh asia 87.0 28.0 500 -500 6000 6000 > myasiagrids.txt.

This creates a grid centered at 28 N, 87 E (west longitudes are negative) with a 500-m grid spacing in both x- and y-directions; the grid has a size of 6000×6000. If you don’t create a grid, the satellite data are placed on the native satellite grid, a grid that changes from day to day for a polar orbiter.

Once the MODIS data has been placed on your local machine, you are ready to use Polar2Grid to query what products can be created using this command

./polar2grid.sh modis gtiff --list-products -f /data-hdd/AckFriendData/MODIS/MOD02_03/day028/;

the -f flag identifies the directory holding the MODIS data and modis gtiff identifies the data type and output files to be created. The result of this is a (sometimes lengthy) list of products that can be created given the input. The following command creates geotiff:

./polar2grid.sh modis gtiff -p vis02 vis06 vis26 --grid-configs /home/scottl/Polar2Grid/polar2grid_v_2_3/bin/myasiagrids.txt -g asia -f /data-hdd/AckFriendData/MODIS/MOD02_03/day028/

This command creates Bands 2, 6 and 26 GeoTiffs, and the data are placed on the ‘asia’ grid defined above (and placed in the myasiagrids.txt file). The grids created do not have georeferencing embedded within the image; that is added with the add_coastlines shell script:
./add_coastlines.sh --add-grid --add-borders --borders-resolution=f --borders-outline='red' terra_modis_vis06_20040129_031000_asia.tif

The add-grid flag inserts lat/lon lines; add-borders includes country borders (with the outline color defined, and the resolution specified; for more control flags, refer to the documentation).

Other CIMSS blog posts that discuss Polar2Grid software are here , here and here.

(Added: GOES-9 was observing this part of the World in early 2004. Visible animations for 28 January and 29 January are available — click the dates).

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EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed Cyclone Amphan during the period when it was rapidly intensifying to a Category 5 storm (ADT | SATCON) by 06 UTC on 18 May 2020. In fact, Ampham became the strongest tropical cyclone on record in the Bay of Bengal basin.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images as viewed using RealEarth (below) provided a more detailed view of Amphan shortly before the time of its peak intensity.

On the following night, toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 (below) showed a subtle signature of mesospheric airglow waves propagating northward away from the center of Cyclone Amphan.

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