University of Wisconsin-Madison Space Science and Engineering Center

CIMSS Satellite Blog

Severe Cyclone Emeraude in the Indian Ocean

March 17th, 2016 | Scott Bachmeier

Advanced Dvorak Technique intensity plot for Cyclone Emeraude [click to enlarge]

A plot of the Advanced Dvorak Technique intensity estimate for Cyclone Emeraude in the Indian Ocean (above) shows that the storm rapidly intensified to Category 4 intensity on 17 March 2016.

Himawari-8 AHI Visible (0.64 µm) and Infrared Window (10.4 µm) images (below; also available as a large 31-Mbyte animated GIF) revealed the formation of a well-defined eye during the day.

Himawari-8 Visible (0..64 µm, top) and Infrared Window (10.4 µm, bottom) images [click to play MP4 animation]

Nighttime images of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) data at 1859 UTC (below, courtesy of William Straka, SSEC) showed the ragged appearance of the eye at that time, with an isolated convective burst that had developed well west of the eye.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Posted in Himawari-8, Suomi NPP, Tropical cyclones, VIIRS | No Comments »

Strong storm over the Upper Midwest and western Great Lakes

March 16th, 2016 | Scott Bachmeier

GOES-13 Water Vapor (6.5 µm) images, with surface analyses [click to play animation]

A strong storm rapidly deepened as it moved northeastward across the Upper Midwest and western Great Lakes on 16 March 2016. GOES-13 Water Vapor (6.5 µm) images (above) showed the evolution of the system as the cloud shield expanded and became more elongated in a west-to-east orientation. On the previous day, this storm produced widespread hail and tornadoes from far eastern Iowa into northern and central Illinois (SPC storm reports).

A closer view of GOES-13 Visible (0.63 µm) images with METAR surface reports (below) revealed the strong winds caused by the tight pressure gradient — a peak wind gust of 61 mph was recorded at Waukesha in southeastern Wisconsin, with multiple power outages across the region caused by wind-related tree damage. Heavy rain (as much as 2-3 inches) produced some minor river flooding in various parts of Wisconsin; across northern Wisconsin, northeastern Minnesota, and the Upper Peninsula of Michigan the rain changed to snow, with as much as 18.5 inches accumulating at Redridge, Michigan, 13.0 inches at Lutsen, Minnesota, and 8.0 inches at Poplar and Sand Bay, Wisconsin. The weight of the wet snow was causing tree limbs to fall, with additional power outages being reported.

GOES-13 Visible (0.63 µm) images [click to play animation]

With the strong winds associated with this storm, there were also scattered pilot reports of moderate turbulence across the region, including 2 reports of severe turbulence over southern Wisconsin as seen below.

GOES-13 Water Vapor (6.5 µm) image, with pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor (6.5 µm) image, with METAR surface reports and a pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor image, with pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor image, with METAR surface reports and a pilot report of severe turbulence [click to enlarge]

Posted in Aviation, GOES-13, Heavy rain / flooding, Winter weather | No Comments »

Moderate to severe turbulence over the Midwest

March 11th, 2016 | Scott Bachmeier

GOES-13 Water Vapor (6.7 µm) images with Pilot Reports of turbulence [click to play animation]

There were numerous pilot reports of Moderate to Severe turbulence (symbols) over much of the Midwest on 11 March 2016, as shown plotted on 4-km resolution GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above). A packet of transverse banding cloud features developed over eastern Kansas after about 1515 UTC, and moved northeastward over northwestern Missouri/southeastern Nebraska/Iowa/northern Illinois/southern Wisconsin during the day.

The transverse banding cloud filaments showed up with a bit more clarity on a 1-km resolution Aqua MODIS Water Vapor (6.7 µm) image at 1919 UTC (below).

Aqua MODIS Water Vapor (6.7 µm) image [click to enlarge]

A MODIS Cirrus (1.4 µm) image at 1738 UTC (below) was also a very effective tool for helping to visualize the transverse banding cloud filaments. A Turbulence SIGMET had been issued at 1433 UTC for much of the region, due to wind shear associated with jet steam aloft. Many of the pilot reports were noted to be Clear Air Turbulence (CAT), with one describing the severe turbulence encounter as “one jolt“. It can be seen from the GFS model isotachs of Maximum Wind that the reports of turbulence occurred within the entrance region of a curved jet stream segment, which are areas that favor the development of strong vertical and horizontal wind shear responsible for turbulence.

Terra MODIS “Cirrus” (1.38 µm) image with Turbulence SIGMET, Pilot Reports of turbulence, and GFS Max Wind isotachs [click to enlarge]

On a comparison of 1-km resolution Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images at 1919 UTC (below), the very thin nature of the transverse banding cirrus cloud features made them difficult to identify on the Visible image; they also exhibited very warm Infrared brightness temperature values (around -15º C) due to the fact that the satellite was also sensing a good deal of warm thermal radiation from the ground surface below the thin cirrus. As seen in the previous example above, the transverse banding high cloud filaments showed up very well on the MODIS 1.38 µm Cirrus image. Imagery from this 1.38 µm spectral band will also be available from the ABI instrument on GOES-R.

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm), and Cirrus (1.38 µm) images, with Pilot Reports of turbulence [click to enlarge]

Hat tip to Scott Dennstaedt for the heads-up on this event:

@CIMSS_Satellite Looks like a nasty turbulence environment today over the Midwest. Lots of urgent PIREPs & SIGMET pic.twitter.com/pc8PU5xsXf

— Scott Dennstaedt (@AvWxWorkshops) March 11, 2016

Posted in Aviation, GOES-13, GOES-R, MODIS | 1 Comment »

Solar eclipse shadow as seen from geostationary satellites

March 9th, 2016 | Scott Bachmeier

Himawari-8 true-color images [click to play MP4 animation]

The shadow of the total solar eclipse of 09 March 2016 was captured by a number of geostationary satellites, including JMA Himawari-8 (above; also available as either a large 140 Mbyte animated GIF, or a YouTube video: large) | small) and KMA COMS-1 (below). The Himawari-8 true-color Red/Green/Blue (RGB) images were created using the Simple Hybrid Contrast Stretch (SHCS) method by Yasuhiko Sumida, SSEC visiting scientist from JMA.