STORM TRACK: May 31, 1984 (Volume 7 Issue 4)

Chase 1984 began for me Monday morning, May 7, when I left Memphis, Tennessee. As already noted, a late morning tornado watch was posted for the northern third of Arkansas. However, local visibility was poor and storms were moving at 50 MPH, so I took a deep breath and let it go. En route, I became interested in radio reports of possible severe weather in central and eastern Oklahoma, along an advancing dry front. My only sky-watch detour was at a small highway restaurant west of Henrietta. By chance, Eric Rasmussen and his fiance, Lisa Walters, had also stopped and were scanning the skies as I drove up. Trying out a borrowed video camera for the first time, I recorded "Raz" in rare and creative form, recounting his NBC interview with Connie Chung (regrettably this inestimable treasure was later accidentally erased). Tuesday to Friday, I quartered at Childress, Texas in hopes of some dryline activity. Unfortunately, the only two notable events during this dreary, hot wilderness hermitage was an ant attack on the way to dinner and a visit to the Childress pioneer museum. At the museum, I learned about a surveyor's chain. On the way to dinner, I learned not to stand too long (!) in one place.

Saturday was spent in Norman, visiting fellow chasers ("misery loves company") but parked up that afternoon, when I saw a large Cb on the O.U. satellite reader in eastern Colorado. I drove to Dodge City that evening and, Sunday, worked over a severe storm in southern Colorado. Although the NWS Limon radar reported a hook echo, I saw nothing in the reported area other than a weak line-echo-wave-pattern.

Qn Monday, May 14, I left the Goodland National Weather Service office and headed west on I-70, with my own 9:00 AM forecast for possible severe weather across the northern half of Colorado (Actually a second choice to my primary forecast area of southeastern Montana; however, this was beyond range for that day, so I opted for the closer area).

By mid-afternoon, skies were still clear and sunny over central Colorado in contrast to the previous day, when anvils filled the western sky. I was beginning to be concerned, until I saw distant towers near Denver. Taking reference pictures as I drove, the towers developed into two small, high base Cbs with narrow, short south-to-north anvils just east of the city (Fig. 5).

Figure 4

Figure 5: Looking SW at 2:43 PM CDT, E of Exit 299/I-70.

Several smaller but weaker anvils and towers were separated from and to the south of these two, while another anvil appeared to the north. Although the latter, at a distance, appeared larger I opted to stay with the earliest development near the city. Except for small, hard but high base towers going up on the south side, most of the Cb bases looked very soft and indistinct, with apparent "virga" (evaporating precipitation) above the ground. The cell closest to me (furthest east of the two) held my attention. As I drove under, a short line of hard, towering cumulus was building into the anvil, just north of the precipitation and apparent base (Fig. 6, from memory).

Figure 6

I continued west and around the north side of Denver, since this development still looked small, although quite striking (sharply defined and solid). Intending to continue north to the Cheyenne area, where I thought the greater dynamics were, I stopped one more time on the north side, at a Holiday Inn near Northglenn, and looked back. There, indistinct between two rain shafts but barely silhouetted to the distant south was an apparent wall cloud. At this time, the higher cloud bases overhead looked very turbulent, as larger, heavier Cbs formed and moved easterly off the mountains. Cloud to ground lightning was moderate and visible even at a distance and in daylight. Looking back at Cheyenne and assuming I would live to regret it, I played a hunch and headed back south, around the north loop, and back east on I-70. The original easternmost anvil had now grown some, but was still short and narrow by Texas or Oklahoma standards (Fig.7, satellite photo reproductions).

Figure 7A: May 14, 1984; 1931Z (2:31 CDT)

Figure 7B: May 14, 1984; 2031Z (3:31 CDT)

At 3:17 PM CDT, I stopped just west of Stapleton airport to photograph a solid, vertical tower building into this anvil, on the north side of the rain area (Fig. 8). The tower was very hard, gray (in the anvil's shadow) and seemingly isolated from other lower level convection, which was almost absent around it.

Figure 8

In Texas, I wouldn't have paid much attention, except this was the only developing part of the cell. The south flank appeared to have rained out and looked soft. Also, a smooth furrowed channel ringed the tower's top, where it entered the anvil. In fact, this is what first caught my attention. Within a few minutes, I saw a thin, almost transparent dust tube from ground to cloud base under the new tower. It was at a slight angle to the horizon, very much like a central plains tornado "roping out," under the southwest flank of a Cb (cumulonimbus) and stretching southeastward, ahead of the rear flank downdraft. Except, in this case, the rope was apparently stretching northwestward, under the northern flank, and beneath an anvil shearing to the north over it (Fig. 9).

Figure 9

Except for the anvil, you could have turned everything around 180 deg and it would have looked just right! I was unable to discern the direction of rotation, as I rapidly drove toward it, stopped for pictures, drove, stopped, etc. Toward the latter stage of its 3-4 minute life, the vortex base developed a more significant dust sheath (Fig. 10). Within a minute or two of its demise, I drove to the Watkins interchange (16 miles east of Stapleton) and about one mile south of its earlier apparent location.

Figure 10

The cell base overhead exhibited no obvious, remnant signs of rotation or concentrated lowering, other than scattered small nodules. While looking almost straight up, half of the base (mostly eastern side) was obscured by high level precip, but the edges remained distinct -- and the base was still essentially rainfree. Only southerly winds were encountered, with light rain (large drops), no hail, no cloud to ground lightning (this cell) and no apparent outflow-gustfront. I wondered then, and still do, if this rotation had been anticyclonic. It did cause slight damage to a farm, removing some siding -- that was about it.

While returning to Denver, 4-5 local radio stations were continuously monitored but, nothing was said about the tornado. The high cloud bases were more stable looking now; seemingly, the whole air mass had now changed. This despite the fact that heavier convection and darker clouds were now passing over onto the Colorado high plains. After trying futilely to raise a "Smokey" or a local "REACT" group on the CB's channel 9, I stopped again at the Holiday Inn (about an hour later) and phoned my report to the Denver police emergency number. The officer at the other end indicated no other reports on this tornado. --- I continued on north to southeastern Wyoming, as anvils quickly covered the eastern half of Colorado. Current radio reports were closely monitored while driving north, but no additional severe weather or boxes were indicated. (Later that night, I did find out that Denver airport had received a pilot's report on the tornado). While gaing through Wyoming and just ahead of a building storm, several local-county warnings were received. However, these cells looked like hailers and I didn't linger to wait them out.

It was a very interesting storm, only my second tornado in Colorado but first along the front range of the Rockies (ergo the additional illustrations and copy for this account). It was fascinating to watch the cells approach, in seeming disarray, across the mountains and -then- become organized over the plains. I hope to have this opportunity again.

The next several days took me into scenic Wyoming, the Blackhills of South Dakota, and back to Norman. The last week was quiet, and I welcomed the arrival of my daughter, Sarah (10), at Will Rogers Airport for her first storm chase. That Thursday, May 24, we charged out to western Kansas and got into the corner of a tornado watch, mostly in northern Colorado. We did see a rapidly building Cb in the Kansas end of the box, which was exciting. While approaching it, Sarah looked over her shoulder and called out in surprise at a new tower going up behind us, where minutes earlier there had been none. Although neither cell produced anything severe, it was a good first lesson on how fast things can change when the atmosphere is unstable. The next day, May 25, we chased east from Dodge City to Joplin, Missouri, where we finally cleared the cold front and got into another tornado box. We were right at the start of the watch and well located for beginning convection at its southwest end. Again, cells went up fast with hard, dramatic towers, but rained out early. We chased from cell to cell and finally caught, a weak wall cloud south of Springfield, before heading home. A stopover and ride up the Gateway Arch in St. Louis was a nice diversion, and the most excitement her dad had had since the Childress ant attack or the Denver tornado. -Some spring!

One note: Sarah was warned about the long, tedious hours of driving, so she brought along four books to read. When these were finished early in the trip, she commented on the long highway hours, and added, "Dad, I want to go with you again next year, but I'll have to bring more books." ... How true, how true.