July 31, 1983David Hoadley, Editor3415 Slade CourtFairfax, Virginia

STORM-TRACK$3.20/year

Vol. 6, No. 5 Bi-monthly (Checks payable to David Hoadley)

I. COMMENTARY

Storm Chase '83 is now over for most of us. Contrary to the expectations for a very active tornadospring, April and May were comparatively quiet through the central plains, with a few notable exceptionssuch as the Houston area storms. Chasers seemed to take turns as different systems presented themselves.Several cars of Norman chasers, with Lou Wicker, joined up with the Editor in photographing at leastthree May 13 tornadoes from Estelline, Texas to Vinson, Oklahoma (See ST, Vol. 6, No. 5); Jim Leonardand Barbara White just missed these vortices but "aced" two high contrast twisters on May 17 south ofMedicine Lodge, Kansas, while the Editor was pursuing a wall cloud northeast of there; and on May 20,Tim Marshall and Roy Britt were all over a multi-tornadic storm near and northeast of Plainview, Texas,which everyone else missed while working storms further east. Something for everyone! Nonetheless, a fewconsidered mid-May as a somewhat spartan period, and Jim Leonard said that he felt lucky to have takenwhat pictures he did. However, the season picked up again in June (Gene Moore photographed several inKansas) and may still yield a substantial number of tornadoes for the year.

- - -In reviewing some old notes from Tim Marshall on the mile wide tornado near Pampa on May 19, 1982, Icame across an interesting observation. One damage report was received on a frame building in its path,which only lost, a roof and part of a wall rather than being virtually flattened as might be expected.In other words, the size of this tornado was not coincident with its severity. Our discussion at thattime led to the thesis that there may be a maximum threshold of vortex diameter, beyond which averagewind speeds do not continue increasing, but begin to decrease, or where suction vortices become lesslikely.Studies may indicate a bell shaped curve thatshows increasing winds for tornadoes up to ahalf mile wide but decreasing winds thereafter,with increasing swirl diameters. In short, themonster vortex may only be an anemic windbag.

- - -Keith Brewster responded to the last Commentary Section in ST. "... you may have heard of a recentlyreleased Dept. of Commerce report, which states that eventually all observations could be made automatedor remotely sensed, and that the primary purpose of the National Weather Service should be severeweather warning and general public forecasting. An obvious contradiction -- any severe weatherforecaster knows the importance of seemingly insignificant remarks such as TCU W, FEW CU and of course-CB DSIPTD! Of course, don't expect your congressman to recognize this."

II. ROSTER

III. LETTERS/PHONE CALLS TO THE EDITOR

On May 20, 1983, Tim Marshall and Roy Britt had an easy chase from their Lubbock, Texas base station toan early afternoon tornadic storm near Plainview, only an hour's drive away. They watched this stormcell develop for over an hour, before the first tornado appeared at 3:18 PM CDT.

For the next 27 minutes and ten miles, theyfollowed it, mainly as a concentrated dust swirlon the ground with occasional suction vorticesbut little indication of a cloud basecondensation funnel. Eleven minutes later theydrove under a rotating wall cloud and justmissed being swept up by a 1/3 mile wide tornadothat dropped down on the road behind them.

*On May 24, Roy and Tim caught up to a severe storm near Silverton, Texas, with a banded base similar tothe Garden City storm of May 30, 1978 (ST: Vol. 5, No. 2). A small funnel was photographed and 80 MPHwinds were encountered.In fact, the blowing dust was so thick that the pavementdisappeared, and Roy ran off the road,-- albeit at very lowspeed. It was then that Tim said, "Here! Let me drive. I canget us out of this!" Whereupon he opened the door and the carwas instantly filled with blinding, storm driven Texas turf.When at last, they arrived in Lubbock, grit and dust coatedcameras, lenses and everything else -- and each chaser lookedmore like a ghost than a person.

*Keith Brewster recounts: "The world's largest 'bust' occurred in southwest Oklahoma, May 17, 1983. As

you may have heard, this chase featured a caravan of 11 vehicles and 32 people, not counting twovehicles from Oklahoma University (TOTO crew , who were within radio range as this group watched ahighly sheared (though very slowly rotating) CB develop on a dry-line near Willow, Oklahoma. Althoughsome severe weather was encountered later by many of the group further north ..., I couldn't decide ifthe highlight of the chase was catching a glimpse of Bill of 'Bill's Safety Cab' in Chickasha, or seeingDon 'DbZ' Burgess standing on the hood of a car to get a measurement with the hand-held anemometer (ofthe 850 mb jet????), as passers-by from the metropolis of Duke, Oklahoma stared at the crowd! By theway, don't believe Don if he tells you the vehicle was hit by tennis-shoe size hail!"

Keith also adds an open inquiry "...I and others here at OU are interested in seeing something onhurricane chasing. What kind of strategy is employed, etc." (How about, it, hurricane chasers? How doyou plan differently for hurricanes, as compared to tornadoes? What different risks do you encounter(flooding, blocked roads, etc.)? What's the best, vehicle to use? -Editor)

VI. BULLETIN BOARD/COMMERCIAL MARKET -$- FOR PICTURES V. CAMERA TIPS VI. TRAVEL TIPS

FUNNEL FUNNIES: Headed Off at the Pass (Fiction)

VII. FEATURE #1 Annual Storm Barbecue

On Sunday, May 15, seventeen tornado chasers showed up at a local Norman apartment for the Annual STORM(Storm Trackers of Oklahoma Ribaldry and Mendacity) barbecue, to eat, drink, swap stories and show stormpictures. As mentioned in the last ST, Barbara White and Jim Leonard were present, showing

video tapes of the May 13 Estelline supercell and of the May 17 Medicine Lodge tornadoes. Jim apologizedat the shaky initial footage for the May 17 storm, taken while standing next to the car, since he waspartially rain soaked from an earlier encounter, and the strong inflow wind was chilling himconsiderably. However, it added a nice human touch to an otherwise very professional showing andexcellent photography.

Among several interesting experiences that were told:

- An account of a St. Elmo's fire electrical/corona discharge in advance of the Blackwell, Oklahomatornado. It happened ahead of the wall cloud but underneath the anvil, appearing as a blue-greendischarge "rippling" back and forth across the ground like a "carpet of fire."

- A Gene Moore account of a rarely heard pulsing, thunder sound, starting as a low "thump" andincreasing steadily but rapidly to a constant thunder-like roar. Heard for 7-8 minutes northeast of theMay 12, 1983 Enid storm, his perception was that the sound proceeded as if from a giant megaphone,pointing at him, and that if he had moved 10 miles in any direction he would have left it. He and EricRasmussen were speculating on possible causes, ranging from a pulsing type of lightning to some kind ofwind-shear induced shock waves. The lightning proposition sounded similar to a remarkable night-timeelectrical display which the Editor witnessed from Bismarck in southeastern North Dakota on July 5,1962. From the center of a large, back-sheared Cb and midway between anvil and cloud base was a rapidlypulsing, very bright electrical discharge, flashing about four times each second and constantly forseveral minutes. It appeared to come from the same location in the cloud, diffused by the cloud massthrough which it passed, and lit up the whole sky. I've not seen the like before or since. The next daythere was a -5 instability in southeastern North Dakota, along with several tornadoes (one reportedlylasting an hour). Gene concluded: "There are things going on out there that we still don't understand."You can say that again.'

- An account of the large and very powerful "Seymour II" tornado of April 2, 1980 (a year after theWichita Falls tornado), wherein a subsequent damage survey showed that even ditches and low areas offerno safety against some storms. Six to nine foot gullies were found denuded of mesquite trees, with onlythe stubs of cactus plants remaining, an almost complete scouring of all living matter. Pebbles werefound imbedded in the remaining and adjacent tree trunks, as if fired from a pistol. Of course, not, alltwisters are this powerful, so that ditches and gullies are still the safest place to be, when in theopen. However, there is evidence that on some occasions you should not expect to emerge from suchlocations in the same condition that you went in.

- On hail. Gene recounted seeing a car roof beaten almost down to the seat tops. Chuck Robertsonreported that the Ringer, Oklahoma tornado cell dropped three different kinds of hail: golfball,baseball and "snowball." The latter had a thick cover of soft ice, surrounded by a small ice core. Whenthe larger hail fell, it left little ice mounds or piles at each impact. Gene said that those who haveexperienced it agree that theres not much warning when big hail starts to fall: "You get a ping, abang, and then a crash!!"

VII. FEATURE #2Clarendon TornadoesBy Tim Marshall

(Editor's Note: An abbreviated summary of this storm appeared in the Marchissue of Storm Data. The following is a more complete account.)

"On March 3, 1983, an early season storm system produced a total of five tornadoes in west Texas andOklahoma. I had the opportunity to photograph two tornadoes near the town of Clarendon, located in theTexas Panhandle (Fig. l from Storm Data, March 1983, Vol. 25, No. 3, with chase route arrows added).

The day began with low overcast skiesin Lubbock. Temperatures were in thelow 60's and dew points in the low50's. NSSFC forecasted a moderaterisk of severe thunderstorms alongthe Red River Valley by lateafternoon. Seeing this, I had alreadydecided to chase that day, whateverthe chances, since it was the firstchase of the spring (and it had beena long, hard winter you know!)

Figure 1

I went to the Lubbock Weather Service and plotted hourly surface analyses. As the morning progressed,

skies remained overcast in west Texas, but I remained hopeful that they would soon clear. By 11 AM, Iforecasted the most favorable area for severe weather to be from Lubbock (LBB) to Fort Sill, Oklahoma(FSI) (Fig. 9).A dryline was developing in southeastern NewMexico and was moving eastward. In addition,a warm front was becoming prominent fromLubbock to near Dallas-Fort Worth (DFW). Ididn't want to travel too far from Lubbock,since I was anticipating convection in closeproximity to the warm front-drylineintersection. I chose the town of Matador asthe "target" town, since it was also southof where previous morning convection hadtaken place.

Figure 2The upper air maps favored severe weather development in west Texas. The area was on the anticyclonicside of the mid-level jet and the cyclonic side of the low-level jet (Fig. 2). With cold air advectiondownstream and a closed low moving into central California, the upper level dynamics were becoming morefavorable for severe weather throughout the day. The morning sounding for Amarillo looked like the'classic' bell shaped tornado sounding from Miller (1972). However, there was little or no wind shearwith height.

Figure 3

At noon, I left Lubbock and drove toMatador. The sky gradually became brokenand small cumulus dotted the sky. Atornado watch was issued along an axisfrom Amarillo (AMA) to Mineral Wells(MWL). Hearing those three beeping toneson the radio brought back the sweet,memories of last May. Naturally, myadrenaline surged! I reached Matador at 2PM. The winds were light southeasterly,and the temperature was about 70 degrees.I could see towering cumulus beginning todevelop along the Caprock escarpment tothe west.

At the same time, smaller cumulus overhead were beginning to dissipate. A small cirrus anvil could alsobe seen to the distant north in association with a developing Cb. I called the Lubbock Weather Service,and they informed me that the dryline was surging from Midland (MAF) toward Abilene (ABI). They said thewind direction at Lubbock had turned southwesterly and the dewpoint had dropped into the 30's.Meanwhile, the wind at Childress was backing more toward the east, and their dewpoint was increasing.Since moisture convergence was increasing in the area, I drove northward toward the developing Cb.

From a rest area north of Turkey, I watched the Cb explode upward to my northwest. The storm was overthe Palo Duro Canyon and moving slowly northeastward over a sparsely populated area, with few roads. Idrove north toward Clarendon, hoping to intercept the storm. I arrived at the town about 4 PM and staredalmost in disbelief at what I was seeing. There was a large bowl-shaped lowering extending from the rainfree base, and it was rotating rapidly. ... I said to myself that this storm must believe it's a May-type storm! (Later, I learned that it went from 38,000 to over 50,000 feet during this time).

I positioned myself just north of theapproaching lowering, just west ofClarendon on FM 2363. Striations wereevident along the east and north sidesof the updraft. I had just set up mycameras on tripods, when the windbecame calm and marble-size hail beganfalling. At 4:50 PM, a large cone-shaped funnel extended toward theground to my southwest (Fig. 3). Theupdraft had a 'step-like' appearance,and the precipitation area to thenorth was quite small. The blue-colored tornado moved slowly northwardacross rangeland (Fig. 4).

Figure 4

Figure 5

A clear slot could be seen wrapping around thevortex. At times, a core could be seen withinthe condensation sheath around the tornado (Fig.5). The tornado began to turn to the northwestand became rope-shaped, finally occluding inprecipitation at 5:11 PM. In all, the tornadotraveled about five miles in twenty-one minutesand was rated F2 (Also, see Fig. 11). Meanwhile,a second updraft developed just east of thefirst and also began to rotate. I moved eastwardout of the path of the approaching updraft. Acell merger was taking place, and theprecipitation area to the north was increasing.Within minutes, precipitation was wrappingaround the lowering.

The lowering moved northward acrossRt. 287, and I could see cars andtrucks driving through the raincurtains and under the impendingcirculation. To the northwest, I couldsee ominous looking cloud bandsspiralling up the east side of theupdraft (Fig. 6). A large inflow tailextended eastward, demarcating theboundary between the precipitationarea and the moist inflow.

Figure 6About 5:45 PM, a rain-laden gust front rapidly movedaround the updraft, originating from the northwest.As the gust front passed my location, a brief periodof rain fell, followed by a wind shift to light west.I continued northward along Rt. 70 and stopped at mysecond filming location, which was on top of theCaprock escarpment, overlooking the GreenbeltReservoir. I could see the occluded updraft to thenorth, with no apparent wall cloud. By this time, thegust front had surged several miles to the east.Then, at 5:59, a narrow column-shaped tornado toucheddown right in the reservoir about two miles north ofmy location (Fig. 7). A spray of water could be seenaround the base of the tornado. Meanwhile, a clearslot wrapped around the updraft, such that theupdraft appeared as a giant cylinder. Figure 7As the tornado moved onshore, it suddenly widened into a large cone-shaped vortex. The tornado travelednortheastward across Rt. 70, just missing the community of Howardwick. One person did suffer minorinjuries, when the tornado flattened a liquor store on Rt. 70.

Figure 8

I drove northward, underneath the darkened updraft,and took a picture of the tornado when it was lessthan a mile away to the northeast (Fig. 8). Thetornado resembled a long tube, and the coreextended to the ground. At times, the tornado movedtoward me, back over its damage path, reminding menot to get too close. In all, the tornado traveledabout five miles in 23 minutes and was rated F2. Itook close to 80 slides and 250 ft of 8 mm moviefootage." Tim reported no tornado sounds of whichhe could be certain. Noteworthy, however, was thelight 3-4 MPH winds beneath and adjacent to thewall clouds; strikingly different from the 60 MPHwinds which Tim experienced along the wall cloudboundary of the May 19 Pampa supercell (six largetornadoes, plus one a mile wide). (Also, see Fig.12)

'In order to better understand how the severe weather occurred, I plotted the 4 PM surface analysis(Fig. 9). It is interesting to note how the warm front moved throughout the day. Note that most of thetornadoes developed along the intersection of the temperature and dewpoint axes. It appeared that therewas enough lifting at low levels, either from isentropic upglide, upslope effects, or the dryline, to

force buoyant air above the inversion and begin the convective process. I learned that the forecast areawould have been more accurate, had I advected the area along with the mean surface winds. Then, in sixhours, the forecast area would have been closer to Amarillo.

Figure 9

Figure 10

Figure 11

VII. FEATURE #IIIAustralian Tornadoes

By Dr. Joseph H. Golden

A copy of the following climatology map on Australian tornadoes was sent to me by Dr. Joseph H. Golden.It was one of several items sent, as a consequence of his six week trip to Australia last year. Joe wentas a Senior Visiting Lecturer in Meteorology to Monash University, near Melbourne. "They do gettornadoes and waterspouts in Australia and Tasmania." Joe said that he "gave several talks to studentgroups and to the Royal Meteorological Society, and aroused a good deal of interest in tornado chasing(on the left hand side of the road!) Joe also photographed a funnel cloud near two New Zealandvolcanoes.

Map prepared by Stuart Allen

VII. FEATURE #IV.Good Plains States

Severe Weather Radio StationsBy Mike Watts

(Editor's Note: Mike sent this prior to this spring's chase, but it couldn't be includedbefore now. Add this to your radio station lists for next spring.)

Wichita, Kansas KFDI-AM 1070 KHZ C&W; Dramamine may be required but their spotters are excellent. Garden City, Kansas KBUF-AM 1050 KHZ One of our clients, should be the fastest, KBUF-FM 97.3 MHZ with storm-related news in the area. Oklahoma City, Oklahoma WKY 930 KHZ severe weather coverage for central and most of eastern Oklahoma. Seminole, Oklahoma KSLE-FM 105.5MHZ coverage east of WKY's. Kansas City. Missouri KLSI-FM 93.3 MHZ concentrates on Kansas City metro area. St. Louis, Missouri KSD-AM 550 KHZ more familiar with the FM; its good with KSD-FM 93.7 MHZ storm information (one of our clients, naturally) but concentrates on the metro area; AM covers a greater area. Salem, Illinois WJBD-AM 1350 KHZ they are very good about severe weather. WJBD-FM 100.1MHZ Aberdeen, South Dakota KGIM-AN 1420 KHZ concentrates on northeastern South Dakota.

Except for KFDI in Wichita, these stations are our clients and will immediately broadcast watches,warnings and advisories that our office provides."

- - -The next ST's Features will include John Weaver's Wyoming chase story "Close Encounters of the RevolvingKind" and Eric Rasmussen's "Tornado Photogrammetry". Also in a future issue -- the antithesis of "TheIdeal Storm Chase" ... "The Abysmal Storm Chasers"

- - -Corrections to last ST: Next to last page - Substitute "JVC CB-P5" for "JVC GZ-S3" and on last page -Change "Sharon Springs" to "Sharon" and delete reference to "(Fig. 8)". [CD-ROM Ed. Note: Corrected]