CIMSS Satellite Blog

Preliminary Damage Results for Port Orchard Tornado have been released. Survey finds EF-2 #tornado damage from Tuesday December 18th. Details in graphic and at: https://t.co/fnaZxgYG6U #wawx #PortOrchardTornado pic.twitter.com/jxpsBgkmgC

— NWS Seattle (@NWSSeattle) December 19, 2018

GOES-17 “Red” Visible (0.64 µm) images, with plots of hourly surface reports and SPC storm reports [click to play animation | MP4]

* GOES-17 images shown here are preliminary and non-operational *

A rare December tornado occurred near Port Orchard, Washington on 18 December 2018. GOES-17 “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed the thunderstorms that moved eastward across the area.

GOES-17 “Clean” Infrared Window (10.3 µm) images, with plots of hourly surface reports and SPC storm reports [click to play animation | MP4]

Due to the relatively large GOES-17 satellite viewing angle (or zenith angle) of 56.38 degrees, there was a modest amount of parallax error in terms of the actual location of cloud-top features associated with the tornado-producing storm. A toggle between 2147 UTC  GOES-17 Visible and Infrared images with SPC tornado report plots at their actual and “parallax-corrected” locations (assuming a mean storm top height of 8 km) are shown below — note how the parallax-corrected tornado plot locations more closely align with the cloud feature of the parent thunderstorm.

GOES-17 “Red” Visible (0.64 µm) image at 2147 UTC, with SPC tornado report plots at their actual and “parallax-corrected” locations [click to enlarge]

GOES-17 “Clean” Infrared Window (10.3 µm) image at 2147 UTC, with SPC tornado report plots at their actual and “parallax-corrected” locations [click to enlarge]

A comparison of VIIRS Infrared Window (11.45 µm) images from Suomi NPP (overpass time 2042 UTC) and NOAA-20 (overpass time 2132 UTC) is shown below. The coldest cloud-top infrared brightness temperatures on the VIIRS images were -42ºC, which corresponded to altitudes of 7-8 km on 00 UTC rawinsonde data from Quillayute, Washington (plot).

VIIRS Infrared Window (11.45 µm) images from Suomi NPP (overpass time 2042 UTC) and NOAA-20 (overpass time 2132 UTC), with the location of the SPC tornado report plotted in red [click to enlarge]

A toggle between NOAA-20 VIIRS Infrared Window (11.45 µm) images at 1952 UTC and 2032 UTC, viewed using RealEarth (below), provided a closer view of the convection.

NOAA-20 VIIRS Infrared Window (11.45 µm) images at 1952 UTC and 2032 UTC [click to enlarge]

from CIMSS Satellite Blog http://cimss.ssec.wisc.edu/goes/blog/archives/31126