May 23, 2009

5/23/09-Part B: Denver Cyclone Produces

Well, on Thom's last day, we actually had a traditional chase.

We dropped down to the Palmer Divide by early afternoon. There seemed to be a boundary with ESE flow south of the Divide and northwesterly or northeasterly winds north of the divide. Low to mid 50 dewpoints abounded.

When we got to Limon, a strong set of echoes was between Colorado Springs and Limon. Just after our arrival there, the northern most of the echoes developed a rain free base, and then, somewhat to my amazement, a fairly good looking wall cloud. We dropped south and noticed that at least at the base of the wall cloud there was decent, but not strong, cyclonic motion.

As the storm moved over us, the wall cloud became outflowish, but left behind on its eastern periphery was the high based funnel, nearly tilted horizontally. All in all, this was a very satisfying chase day. We salvaged an actual chase out of this wreck of a pattern. It also goes to show that what meteorologists call "mesoscale"accidents can produce bounty. A "mesoscale accident" is something that cannot be assessed by looking at computerized weather forecasts, but changes conditions favorable to those for rotating storms by some local effects that are difficult to assess, if not impossible (topography, boundaries from neighboring thunderstorms etc.) True, we did not see a tornado. But others reported brief tornadoes. Our high-based funnel is consistent with those reports.