Cyclonic Development in the Indian Ocean

November 10th, 2021 |

A tropical cyclone has developed in the Bay of Bengal and is moving northwest across the Indian subcontinent. The system is forecast to continue bringing heavy rains to Southern India until Thursday. It has already caused damage, flooding, and loss of life in Sri Lanka and India.

Animations showing water vapor data from the Himawari-8 satellite’s Advanced Himawari Imager (AHI) can be found below. The first animation highlights cyclonic structure developing over the past two days every hour. In the final frame, a distinct eye is visible. Similar to the ABI aboard GOES-16/17, AHI collects data every ten minutes. The second animation shows the ten-minute temporal resolution of AHI for a shorter time period, zooming to see the ‘eye’ of the storm.

An hourly animation spanning 48 hours visualizing cyclone development using AHI Band 9 data in RealEarth, from 11/8/2021 20:57 UTC to 11/10/2021 20:57 UTC.
A zoomed-in view using the ten-minute data from AHI Band 9 data in RealEarth, on 11/10/2021 from 13:50 UTC to 22:10 UTC.

These animations were made using RealEarth, a free data discovery and visualization platform developed at SSEC/CIMSS at the University of Wisconsin-Madison. It is available to anyone at

RealEarth also contains CMORPH estimates (hourly, daily and weekly) of precipitation. The daily precipitation from 10 November over the Bay of Bengal is shown below. The highest value in the colorbar is 150 mm — but in reality, the heaviest accumulations over the Bay of Bengal exceeded 300 mm!

Accumulated precipitation, estimated from CMORPH, for the 24 hours ending 2359 UTC on 10 November 2021 (Click to enlarge)

Solar Flare detected by GOES Solar Ultraviolet Imager (SUVI) telescope

October 28th, 2021 |

Sometimes space weather can be just as noteworthy as weather on Earth. There was an X1 solar flare on October 28, 2021, at 10:35AM CDT (15:35Z) detected by the GOES Solar Ultraviolet Imager (SUVI). The GOES-16 and 17 satellites each house the SUVI, which is an extreme ultraviolet telescope that detects photons that are not detectable from the Earth’s surface.

This type of X1 solar flare event can affect Earth’s conditions. Today’s solar flare is associated with a “strong” R3 radio blackout in which high frequency radio communication can be impaired. The NOAA Space Weather Prediction Center (SWPC) is responsible for observing and forecasting flares. More information is available here.

The GOES-16 Solar Ultraviolet Imager (SUVI) detects a solar flare at 304 Å occurring at 15:35Z October 28, 2021.
The same flare from SUVI observed at 171 Å.

This SWPC site shows solar animations at various wavelengths and updates in real-time.

NOAA SWPC is also in charge of monitoring and forecasting aurora (the northern lights, aurora borealis, or southern lights, aurora australis). Aurora occur as a result of solar flare activity that releases energy into Earth’s magnetic field. NOAA Space Weather has issued a “G3” geomagnetic storm watch, predicting aurora visible as far south as Pennsylvania, Iowa, and Oregon through this Saturday October 30. More information on aurora and aurora forecasts can be found here.

To visualize different characteristics of the sun, CIMSS scientists have built a webapp tool called an “RGB maker” for SUVI data in which data at three different wavelengths are combined to create an image. You can find the tool here. (Note for users: select your red, green, and blue wavelengths and then combine channels. General users can ignore adjusting the scale and gamma factors.)

The SUVI RBG maker functions similarly to how traditional Red Green Blue satellite composites are created, only it combines from the six SUVI bands. Those band wavelengths are: 94 Å, 131 Å, 171 Å, 195 Å, 284 Å, and 304 Å. [One Å (pronounced Angstrom) is equal to 0.0001 microns or 1e-10 meters.] The table below lists the type of solar phenomena that are observable with each band.

Six wavelength bands detect solar phenomenon on SUVI. Space weather forecasters use this data to observe solar flares and monitor Coronal Mass Ejections (CMEs), for example.

Here are some examples of solar RBG composites created with the CIMSS SUVI RGB maker.

A SUVI composite made with the CIMSS RGB maker combining channels 131 Å, 171 Å, and 195 Å.

A SUVI composite made with the CIMSS RGB maker combining channels 304 Å, 171 Å, and 195 Å.

Severe Weather in the Southeast United States

October 27th, 2021 |

This morning brought a line of severe weather, rain, and thunderstorms to parts of Texas into Louisiana. The system moves eastward, already delivering on a threat of severe weather. As of 2:08 PM CDT (19:08Z) today, October 27, 2021, there is an active tornado warning in multiple parishes throughout Southern Louisiana. The system will continue to move through the Gulf Region through Thursday.

A “line” system associated with severe weather moves over East Texas into Louisiana as seen in this 5-minute GOES-16 ABI Band 2 animation (visible wavelength, 0.64 microns). The ABI Band 2 data has spatial resolution at 0.5 km, making it useful for the analysis of small-scale clouds in rapidly changing weather systems such as this one.

Viewing Fall lightning with RealEarth

October 21st, 2021 |

Cooler temperatures across the Midwest are often heralded by thunderstorms. Yesterday evening and last night, a system brought rain and lightning to parts of Iowa, Minnesota, Wisconsin, Illinois, and Michigan, moving over Ohio by Thursday morning. RealEarth, a web-based visualization platform developed at UW-Madison, can display data from GOES-16 to monitor such events. RealEarth’s data archives usually go back at least 24-hours which provides temporal context to weather events.

RealEarth is a free data discovery and visualization platform developed at SSEC/CIMSS at the University of Wisconsin-Madison. It is available at

A 24-hour animation every hour from RealEarth (time in UTC) showing GOES-16 ABI Band 13 with the purple areas representing lightning. More specifically, the purple areas depict Flash Extent Density from the Geostationary Lightning Mapper (GLM) also aboard GOES-16.