Tornado near Eureka, California

By Scott Bachmeier • 25 January 2018

A waterspout developed over Humboldt Bay Thursday, January 25th around 4:40 pm and moved through the Woodley Island Marina, dissipating only a minute or so later. Security cameras captured the waterspout moving through the marina onto the island. https://t.co/EIgAPN2BTE

— NWS Eureka (@NWSEureka) January 27, 2018

A waterspout moved inland near the NWS Eureka forecast office during the late afternoon hours on 25 January 2018. The brief tornado caused some EF-0 damage (interestingly, it was the only report of severe weather in the US that day, and the first tornado in the Eureka forecast area since 1998).

A comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed the line of convection as it moved across the area (Eureka and the location of the 0040-0041 UTC tornado are a few miles south-southwest of the airport KACV) — the coldest cloud-top infrared brightness temperatures on the 0037 UTC and 0042 UTC GOES-16 images were -30.7ºC (dark blue color enhancement). Note: there were no western US images available from GOES-15 (GOES-West) between 0030 and 0100 UTC, due to a routine “New Day Schedule Transition” and a 0051 UTC Southern Hemisphere scan.

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with plots of hourly surface reports [click to play animation]

There was an overpass of the NOAA-19 satellite about 2 hours prior to the Eureka tornado, at 2251 UTC. If we compare the NOAA-19 Visible (0.63 µm) image to the corresponding GOES-16 Visible (0.64 µm) image (below), a parallax shift to the west is evident with GOES-16 (which was scanning that same scene only 24 seconds later than NOAA-19: 22:52:23 UTC vs 22:51:59 UTC).

NOAA-19 and GOES-16 Visible images at 2252 UTC, with plots of 23 UTC surface reports [click to enlarge]

In the corresponding Infrared Window images from NOAA-19 (10.8 µm) and GOES-16 (10.3 µm) (below), the parallax shift was also apparent — and the coldest cloud-top infrared brightness temperatures associated with the convection just northwest of KACV were -36.2ºC and -35.2ºC, respectively. Given the very high viewing angle for GOES-16 (about 67 degrees over Eureka), the qualitative and quantitative satellite presentation compared quite favorably to that seen from the more direct overpass of NOAA-19.

NOAA-19 and GOES-16 Infrared Window images at 2252 UTC, with plots of 23 UTC surface reports [click to enlarge]

As mentioned in the afternoon Area Forecast Discussion, offshore Sea Surface Temperature (SST) values were in the 50-55ºF range; this was also seen in a comparison of the nighttime and daytime MODIS SST product (below). With the presence of cold air aloft and relatively warm water at the surface, the lower troposphere was unstable enough to support the development and growth of showers and thunderstorms.

MODIS Sea Surface Temperature product [click to enlarge]

Categories: AVHRR, GOES-16, MODIS, POES, Severe convection

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Tornado near Eureka, California