Severe weather across Indiana and Ohio

November 5th, 2017 |

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red (on Visible images) and black (on Infrared images) [click to play MP4 animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red (on Visible images) and black (on Infrared images) [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

An outbreak of severe weather occurred across the Midwestern US on 05 November 2017, with a number of tornadoes (including a 39-mile long track EF-2 tornado) in Indiana and Ohio. A GOES-16 Mesoscale Sector provided imagery at 1-minute intervals during this event — “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) with plots of SPC storm reports (T=tornado; W=damaging winds; H=hail) showed the development and motion of the severe thunderstorms. The locations of the plotted SPC storm reports have been parallax-corrected upward from the surface, to match a mean storm-top height of 10 km.

A toggle between Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) showed a snapshot of the storm at 1803 UTC. SPC storm reports within about  +/- 30 minutes of the image time are also plotted. The coldest storm-top infrared brightness temperatures were -71ºC (black enhancement), over southern and eastern Indiana. The VIIRS instrument will also fly on the JPSS series of satellites.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

One interesting aspect seen on 1806 UTC Aqua MODIS Water Vapor (6.7 µm) imagery (below) was the signature of strong subsidence (darker blue enhancement) immediately upwind — along the western edge — of the 2 larger areas of severe convection. Once again, SPC storm reports within about +/- 30 minutes of the image time are plotted.

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images, with SPC storm reports [click to enlarge]

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images, with SPC storm reports [click to enlarge]

Additional information on this event can be found on the Satellite Liaison Blog, as well as the NWS forecast offices at Indianapolis IN, Northern IN, and Wilmington OH.

Unusual October Tornado in Wisconsin

October 7th, 2017 |

GOES-16 ABI Visible (0.64 µm) Imagery, 2042-2227 UTC on 7 October 2017 (Click to animate)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

October is typically not a month when tornadoes are expected in Wisconsin. (And in fact, the month ranks fourth in the numbers of fewest tornadoes nationwide). Nevertheless, a brief tornado occurred on the east side of Madison WI late in the afternoon on 7 October (NWS Milwaukee/Sullivan). The visible animation, above, from GOES-16, shows a thin line of weak convection moving through the central part of the state. A slower animation centered on the reported time of the tornado (2200 UTC), is below. The dynamic state of the thunderstorm tops is apparent, and the 5-minute time-step may not be sufficient to resolve the small time-scale changes in the tornadic storm (the two GOES-16 Mesoscale sectors that provide 1-minute imagery were covering the pending landfall of Hurricane Nate at this time, and were giving severe weather support to Puerto Rico, radar-less in the wake of Hurricane Maria).

GOES-16 ABI Visible (0.64 µm) Imagery, 2152-2222 UTC on 7 October 2017 (Click to enlarge)

The Clean Window Channel, below, with the default AWIPS enhancement, shows little cloud-top structure.

GOES-16 ABI Infrared (10.3 µm) Imagery, 1917-2302 UTC on 7 October 2017, default enhancement (Click to animate)

Coldest cloud-top brightness temperatures with this event were in the -15º to -20º C range, and the default enhancement (with a range from -109º to 55º) showed little gradation in that range. By changing the coldest temperature in the enhancement from -109º C to -43º C, however, a structure in the cold clouds emerged, as shown below. Do not be afraid to change enhancements!

GOES-16 ABI Infrared (10.3 µm) Imagery, 1917-2302 UTC on 7 October 2017, adjusted enhancement (Click to animate)

The NOAA/CIMSS ProbSevere products for this event is shown below (from this site). ProbTor values were negligible; however, ProbWind values for the tornadic cell were around 20-24% leading up to the event. In addition, the cell that produced the tornado had the highest probabilities in the identified cells along the line of convection. The single exception occurred at 2235 UTC, after the severe weather event, when the cell to the north briefly (for only five minutes) showed Probabilities exceeding 40%.

NOAA/CIMSS ProbTor, 2130-2235 UTC on 7 October 2017 (Click to enlarge)


============================== Added =============================

The National Weather Service in Milwaukee/Sullivan WI determined that the tornado was an EF-0 based on a damage assessment. They provided radar imagery at the start of the tornado, during the tornado, at its end, and after dissipation.

Weak tornado in San Juan, Puerto Rico

October 6th, 2017 |

An email from SSEC/CIMSS employee Shane Hubbard discussed details of a weak tornado in San Juan, Puerto Rico on 06 October 2017:

While I was working in San Juan last week a tornado formed close to the shoreline of Lake (Lagoon) Los Corozos, moved over the water, and then damaged homes in a neighborhood named ‘Playita’ where I was working. The tornado formed near 18.439089, -66.041962 on October 6th around 4:25pm AST. 10+ roofs were damaged from the event. Many of those roofs had already been repaired by residents or by the carpenters that were volunteering in the community. It was a very depressing event to say the least.

Here are links to the tornado.

Approximate tornado path (courtesy of Shane Hubbard)

Approximate tornado path (courtesy of Shane Hubbard)

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly San Juan surface data plotted in yellow [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with hourly San Juan surface data plotted in yellow [click to play MP4 animation]

A GOES-16 Mesoscale Sector remained positioned over Puerto Rico (to support their lack of weather radars, which were destroyed by Hurricane Maria; click here for a Tweet from NWS San Juan showing their radar damage) — “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the region around San Juan (station identifier TJSJ).  An Infrared animation covering the time from 1915 UTC to 2054 UTC, displayed at the GOES-16 ABI full 12-bit depth (created using SIFT) is shown here; a visible animation is available here.

Convective initiation occurred over the far eastern end of the island about an hour before the tornado — cloud-top infrared brightness temperatures cooled to around -70ºC (black enhancement) around the time of the tornado (2025 UTC) during a second burst of convection.

Of particular note is the speed with which the second convective storm grew.  Between 2020 UTC and 2025 UTC, the cloud-top infrared brightness temperatures cooled 20ºC in the region of thunderstorm development!  The bar graphs below show the brightness temperature distribution in the region of convective development.

Cloud-Top Brightness Temperatures over a Tornadic Convective Storm at 2020 and 2025 UTC on 6 October 2017 (Click to enlarge)

The animation below shows GOES-16 10.3 µm Clean Infrared Window images for 10 minutes: 2017-2026 UTC on 6 October. Very strong convective development is apparent, overlapping with the 2025 UTC time of the tornado.

GOES-16 “Clean Window” 10.3 µm Imagery, 2017-2026 UTC on 6 October 2017 (Click to enlarge)

GOES-16 views Thunderstorms in northern Minnesota

September 15th, 2017 |

GOES-16 (left) and GOES-13 (right) views of thunderstorms over northern Minnesota. Top: Visible (0.64 µm) ; bottom (10.3 µm , left; 10.7 µm , right), 2000 UTC – 2350 UTC on 14 September (Click to animate)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

GOES-16 and GOES-13 animations of thunderstorms over northern Minnesota, above, courtesy Science and Operations Officer (SOO) Dan Miller from the Duluth National Weather Service Office, show how the superior spatial and temporal resolution of GOES-16 enhances the ability to monitor the evolution of storms. Not only are the individual cold overshooting tops much more apparent in the nominal 2-km resolution Infrared imagery of GOES-16 (lower left) (vs. 4-km for GOES-13 in the lower right), but their evolution is better captured by the 5-minute temporal cadence for GOES-16 (vs. 15-minute for GOES-13).

Visible (0.64 µm) imagery from GOES-16 (upper left) also has better spatial (nominally 0.5 km) resolution than GOES-13 (upper right, nominally 1 km). Note that the black points at the start of the animation in GOES-16 are regions of very high reflectivity that — for now — are incorrectly set to missing in AWIPS. Consider, for example, the visible signatures of the overshooting tops in GOES-13: are you certain you are tracking the same feature with the 15-minute time step? GOES-16 data show that overshoots can emerge and decay much more quickly than every 15 minutes!