July 21, 1996 Colby, KS/July 23 Limon, CO Chases By Martin Lisius


The following are very brief chase accounts for the Colby, KS and Limon, CO
tornadoes of this past week.  I will do an in-depth after I have time to get
some sleep.

Colby, KS, 7/21/96

Looked at early SPC outlook at 5 am in DFW.   No risk posted for NW KS.  But I
saw good progged 30 kt NW winds and decent (10 kt) SE surface winds with
moisture.  Also, read GLD FE which mentioned "pseudo dryline" setting up later
in forecast area.  That's exactly what happened.

I watched two pretty good cells go up NW of our position just SE of Colby.
Winds were ESE at about 15 and gusty.  Air was sun warmed and humid.

A lowering on the southern storm just south of Colby caught my eye.  It quickly
fell apart as a t-storm warning was issued for it.  But the tower on the norther
storm near Colby looked very interesting.  It was pretty hard and with a dark
base beneath.  Moments later, a funnel came down creating a dust whirl beneath
about a minute later.  Another minute oassed and the tornado was a solid, Wizard
of Oz "tube."

We watched and video taped over its 25 minute life from the SE with great
contrast.  We moved within a mile of it just in time to see it rope out and
leave a plume of dust suspended above the ground.

The little supercell had shrunk from a decent sized storm to a tiny, rapidly
rotating updraft.  It looked really strange at the end right before the tornado
died.  The storm was not a whole lot bigger than the tornado by that time!

We proceede south to watch several wall clouds on other cells and get bashed by
large golfballs about 2 south of Monument, KS.

Limon, CO 7/23/96

Greg Thompson, Dave Blanchard and I looked had lunch and looked at data at NCAR
in beautiful Boulder.  During lunch, cells went up overhead.  We jumped in our
vehicles and headed SE to neaar Byers on I-70 to stand in cold, second wave, and
strong NE winds.

We were very depressed as the AM outlooks did not suggest this.

We saw a cell go up just south of Byers on the Palmer Divide.  Craig Setzer gave
us a radar report for it and we tracked it as it cruised SE toward Limon.
Suddenly, a new cell went up just ENE of the original.  We drove just past the
old Limon radar site and spotted a tornado on the ground to our south!  The
dark, pencil-shaped twister raced west between the two rain shafts.  It was on
the gound for about 3 minutes.  Another mile, or so, south we reached the damage
path.  A barn had been heavilly damaged with large pieces on the road along with
a tree.

Outflow dominated the rest of the day.

Both chase days saw tornadoes EARLY in the convection period.

Martin Lisius