May 17 - Colorado supercells and super colours!

We've had some down time the last 5 days or so which gave us a chance to visit the Twister Museum in Oklahoma, drive through the town of Greensburg, Kansas (which was destroyed by a 2 mile-wide tornado in 2007) and also cross some of the Rocky Mountains to see and climb the 200m high towering Great Sand Dunes in Colorado. Now we're back on the plains chasing storms.

Began today in Limon, Colorado looking at a target area of NE Colorado and a setup that included only a very low chance of tornadoes developing on storms that would be reliant on 'upslope flow' (moisture rising in elevation as it moved north-westward over increasing land elevation from the southern plains).

The dew points for the region were forecast to be in the low 50's F, which ordinarily is not enough to support severe storms on the plains. However, the elevation of NE Colorado (with a surface pressure near 850 hPa!) and geographical features that promote the 'lift' that storms need for initiation often overcome this in situations with flow from the east.

We initially moved east toward Burlington nearer the Kansas border due to low moisture in our target area, however as you'd expect when you change your target, the original area fired and we set out to intercept a storm that formed near Last Chance (around 30 miles from Limon).

This storm moved northeast and was quickly severe warned and shortly thereafter tornado warned. Much to our surprise the low-precipitation (LP) type storms we anticipitated failed to eventuate, and high precipitation (HP)/bowing segments dominated the storm mode in the moderate deep layer shear and this was despite CAPE (energy available for storms) of at most 750 J/kg (a normal summer time thunderstorm might have as much as 1500 J/kg).

We managed to get onto the increasingly large thunderstorm as it looked impressive on radar and got some impressive structure near Akron 

However it soon became clear that a newer storm to the southeast was likely to cut this storm off from its critical moisture flow and cause it to weaken. Using a few back roads and the 4WD we managed to drop south onto the now tornado-warned storm near Anton that produced a few weak landspouts. The structure looked fantastic as we saw a number of rotating wall clouds within the complex structure (it looked very odd)

 

Rotating wall clouds occured within what was becoming an increasingly hybrid structure. While we saw a number of funnels and some strong rotation including directly above us, the relatively elevated bases meant that the tornado we wanted was nearly impossible.

 As the sun set the colour and storm scene was simply amazing. 

We followed the growing complex SE towards burlington and saw a great lightning display (while driving of course) and encountered hail as large as go lf balls and possibly larger, though most of it was soft and posed little threat to the car.  While Crikey was in the passenger seat he got a bit creative:

We ended the chase with a long drive south east to Dodge City, Kansas to prepare for a likely active period of chasing in the traditional tornado alley. Please note we will update as often as we can, however we are limited somewhat by connectivity and time when repositioning some distance between chasing targets. Videos may be delayed several days due to time required to show you what we have seen. We don't really want to bore people with non-storm chasing posts.

Feathers and Crikey