Day 143: Tornadoes in Northwest Kansas

Posted by pmarsh on 23 May 2010 | 0 comments

For day 23 of VORTEX II operations the armada targeted west central Kansas. The day started in North Platte, Nebraska, took them as far south as Garden City, KS, and will end with them located farther north. (Check back tomorrow for the actual location.)

The armada had a difficult day with storms developing rapidly, in several locations, and moving north-northwest at high speeds. The storm motion made deployment opportunities difficult and the fact there were numerous storms to choose from (and watch out for) made data collection extremely challenging – but a challenge the armada was up to. The storm V2 targeted is circled in orange (below) and had a tornado warning on it at one point. The storm’s rotation looked fairly good on radar and spotters reported brief funnel clouds, but it never produced a tornado.

Ironically, one of the sounding units (circled in yellow) was in position to observe the storm VORTEX II targeted as well as the storm immediately to the north. The northern storm (circled in red), actually went on to produce a tornado. Because Kansas is so flat, the sounding unit was able to observe the tornado from over 15 miles away! Amazing!

This wasn’t the only tornado of the day in Kansas. In fact, it was just getting started at this point. As the armada was heading back to their hotel because of darkness, strong rotation developed to the northwest of Goodland, Kansas.

The radar images above and below (same image, just annotated below) capture the tornado (area circled in yellow) and a developing tornado (area circled in orange). The radar is sampling the tornado (yellow circle) at a height of 300 feet above the ground. In other words, the velocities being displayed in this image are what the radar believes the wind speeds are of air moving toward the radar (greens and blues) or away from the radar (reds and oranges). Whenver these colors are immediately next to each other it means that the wind is either rotating, coming together (convergence), or going apart (divergence). In the examples above, the air is rotating, and quite rapidly. (I’ll do a post on radar analysis in the near future to explain how to tell if the air is converging, diverging, or rotating.) The values of the winds in this post are approximately 70 knots away from the radar and 40 knots toward.

The orange circle has a much weaker circulation, but it is one nonetheless. In the images that followed (not displayed here), the tornado (yellow circle) weakened and the developing tornado (orange circle) took over. This is known as a “tornado cycle”, or “cycle” for short. The thunderstorm that produces these “cyclic tornadoes” is known as a “cyclic supercell”.

I should add that the forecasters at the National Weather Service office in Goodland, KS were able to see these tornadoes from their office. They were also able to see a tornado on the southwest side of the city a little bit earlier!