March 28, 2007
Storm Chase
Texas Panhandle
Editor: Putnam E. Reiter
Forecast/Setup -
Risk Area: Enhanced Moderate Risk
Initial Target Area: Hollis, Oklahoma
After a rather cold late January into
February, the area warmed up as March started.
However, despite the warmer conditions, the
mid-level pattern was not favorable for thunderstorms. A Canadian cold
front moved through the region in early March and this pushed deep moisture out
of the Gulf. The high stayed just off the eastern U.S. coast as the
atmosphere was in a blocking pattern and a longwave ridge was over the eastern
U.S.
In mid-March a southern stream
system moved into the southwest U.S. and closed off as it moved slowly through
northern Mexico. This system was supposed to produce widespread rainfall
across the area, but the southern track and it hanging back west kept the
rainfall in western Texas and New Mexico. An active severe day did occur
in west Texas around March 23rd. The closed low traveled north-northeast
into New Mexico and eventually Nebraska. Due to the prolonged period of
southerly flow across Oklahoma/Texas, upper 50s/low 60s dewpoints were common.
As the upper system left, there was no change in the lower level airmass.
Models consistently progged
another southern stream system to move into the U.S. and progress rapidly east
into the plains by the 28th. While there were varying solutions among the
medium range guidance, there was enough agreement to believe that severe weather
was possible. One reason is that moisture would not be a problem as the
Gulf had not been wiped out by cold fronts within a few weeks.
Additionally, there were no ridges along the coast to block moisture return.
The large surface ridge off the eastern U.S. coast continued to influence the
Gulf resulting in modified moisture into the Plains. However, as the
longwave trof moved into the western U.S. this surface ridge was progged to
weaken and shift east. This would allow deep layer moisture to continue
flowing across Texas/Oklahoma and up north into Nebraska. The resulting
atmosphere was characterized by mid 60s dewpoints in Texas/Oklahoma with low 60s
dewpoints into Kansas.
Model runs through the 4-6 days out
consistently showed the upper system moving
rapidly into the U.S. and then closing off over the north-central U.S. as the
eastern longwave ridge intensified. Around 3-4 days out the ECMWF changed
the solution going with a more southern closed low over Colorado, it also
slightly slowed the system. I ignored that solution and stayed with the
NAM/GFS. Several NWS offices, including the HPC sided with the ECMWF.
By Tuesday (the day before) the NAM/GFS had made a slow change towards the
ECMWF. One thing I didn't like about the ECMWF's solution was its dryline
placement on I-27. The GFS/NAM consistently progged the dryline into
western Oklahoma. However, Tuesday the GFS had brought the dryline farther
west. My forecasts had already accounted for a westward shift, but not to
I-27.
SPC had outlooked much of the
central U.S. in their Day 4-8 for several days. The Day 3 for this event
sported a slight risk with a 30% area from southern Texas into Nebraska.
The Day 2 had a slight risk with essentially the same 30% area with a 10%
hatched area across parts of west Texas into Nebraska. The Day 1 kept a
similar area but started nudging the threat west. By the Day 1 at 16:30z
the moderate risk had been moved west to the central Texas panhandle.
Our chase group had decided
several days in advance that Wednesday looked like a good day to chase.
Moisture was in place with decent thermodynamics progged across the threat area.
The upper system was well timed, especially given strong winds aloft. Two
downers were that directional shear didn't look great on all the models and the
far west placement of the dryline. SPC and local NWS offices noted that if
surface winds backed more than models progged, this would increase the severe
threat. As it turned out, the surface winds did back across the threat
area. The main issue of the day was widespread cloud cover across the
threat area. However, the cloud thinned enough for warming to take place
and this resulted in widespread CAPE values above 2000 J/Kg and LIs below -6,
isolated areas had better values. With better surface heating the cap
(EML) should give with rapid storm development occurring by late afternoon.
Storms developed around 16:00 CDT in the
eastern Texas panhandle southwest of Wellington and north of Lubbock near
Plainview. A PDS tornado watch was already in affect and the Wellington
storm prompted a tornado watch for western Oklahoma into northwest Texas.
The Wellington storm moved rapidly north and appeared to be elevated. This
storm continued to move north into the northeast Texas panhandle where several
other storms developed with it and eventually a supercell emerged out of the
cluster. This supercell moved north into Beaver County and produced a
tornado, which killed two people near Elmwood. Back north of Lubbock two
supercells emerged and moved north. They also had a tendency to split.
These two supercells tracked north-northeast and produced several tornadoes.
Another storm develop just northwest and also produced a tornado. One of
these storms killed a person at I-40. They eventually merged into a
cluster in the northeast Texas panhandle. By 9pm a squall line had
developed along the dryline and was moving east across the Texas panhandle.
SPC Products:
SWO
Day 1
Graphics:
Risk Area
-
Tornado
Prob -
Damaging Wind Prob -
Hail Prob -
Storm Plot
- LSRs
- MCD's - Watch
Sounding:
AMA ARPS - 21z
GFS 00z Initialization:
Surface Pressure
- Dewpoints -
CAPE
- 850mb
Temperatures -
850mb Dewpoints
- 850mb Wind -
850mb Relative Humidity
- 700mb Wind
- 700mb
Temperatures -
700mb Relative Humidity
- 500mb Temperature
- 500mb Wind
-
500mb Relative Humidify
- 500mb Vorticity
- 400mb Wind
- 300mb Wind
-
250mb Wind
- 250mb Relative
Humidity - 200mb Wind
Hook-Echo Discussions for this event.
RADAR Loop from Amarillo
The Chase -
Team 1 - David
Underwood, Rob Ferguson, and Putnam Reiter
Miles Driven - 520
Departure Time - 13:00 CDT
Return Time - 23:25 CDT
We left Oklahoma City a little after 13:00 for our target area
in Southwest Oklahoma. Andy tried to convince me to go out I-40, but I had
no interest in changing my location. I had already agonized over the
target spot enough the past 24 hours. My difficult was choosing between
Sayre and Hollis. I also knew that the dryline was farther west and we'd
have to head deeper into the Texas panhandle. I liked the higher CAPE
values in the southern part of the panhandles, especially given the cloud cover
that had invaded the region much of the day. There are chase days,
especially in late May into June when you have to be careful of the southern
storms. And, on other days you want to be on tail-end-Charlie. I
felt that Wednesday was one such day. The issue of dealing with a meat
grinder wasn't too prevalent given temperatures in the mid-70s and dewpoints in
the mid-60s.
We headed southwest on I-44 looking at data as we went.
There wasn't much going on as we had left early knowing it was a long drive.
We also knew that we'd end up in the Texas panhandle before the day was out.
So, I got that question out of the way early and we decided to shift our target
to Memphis, Texas. We got to Lawton around 14:15 and I dealt with a data
problem while in a good cell range. We went west on HWY 62 towards Altus
and I got the data problem fixed. We listened to amateur radio on the way
as the NWS was issuing periodic weather updates. As we got close to Altus
SPC issued a tornado watch for the Texas panhandle and enhanced it to a PDS.
There was also talk about development south of Childress. We toyed with
sitting in Hollis, but with the dryline so far west, we decided to stay on our
west heading. We also learned that the area from Plainview to Amarillo to
Childress was being closely monitored for development. This was good since
we lost cell coverage as we got west of Gould.
We got into the Texas panhandle shortly after 15:00 and
continued on west via HWY 62. We turned north briefly on HWY 83 and then
turned back west on HWY 256. We got about 7-8 miles west on HWY 256 and
decided to stop as we saw lots of enhanced cumulus. We sat here for a
while and watched the clouds. I was in my, well at the very least we can
watch the clouds for a while mood. Then we heard of development near
Plainview and also saw it on RADAR since we had data. About 16:15 we
noticed an area of 30dbz on RADAR and believe that would be our first storm.
I was getting orientated and thought the storm was to our south. However,
when I looked north with cumulus rapidly rising I figured out we were three
miles from that area. We decided to turn around and head to Wellington.
We could have gone up to 388, but decided to stay on the main roads. We
followed the storm to Wellington and it had a 50dbz core.
However, it was elongated and showed no signs of organizing. It also was
moving really fast indicating that it was not rooted in the boundary layer.
About this time I noted on RADAR that the activity near Lubbock was much better
organized and had developed into supercells. So, I recommended we turn
around in Wellington and head back towards Memphis.
We reached Memphis and got word of a tornado warning for the
Plainview area. This encouraged us to step it up some to reach the storms.
At this point I was struggling with storm motion. I knew the storms were
moving north-northeast but I'm conditioned to think of them moving northeast and
even east. So, I recommended that we turn south on FM 657. About
17:24 CDT we got close enough for storm scale features and say a lowering.
It had an extension that looked like a funnel and could even have been a
tornado. However, we were still a long ways away and wouldn't call it
such. I called a turn south on FM 657 thinking that was a good move,
however as soon as we turned I realized that was a mistake. Conferring
with Rob we agreed that it was best to turn around and go back to HWY 256 and go
west.
We drove past Brice where HWY's 70 and 256 merge and head
southwest. We stopped just past County Road 1 to watch the storm.
Here we had a pronounced lowering to our southwest with scud rising into the
circulation center. Time was about 17:49 CDT. Now, it is certainly
possible that we had a tornado before this point and it is on video.
However, around 17:50 CDT we got our first tornado on the storm southwest of
Silverton. The tornado was brief, lasting only a few minutes. We
continued watching the storm and another tornado developed around 17:57 CDT.
This one was also brief, lasting till about 18:00 CDT. We started to lose
features on this storm and knowing that road options were limited, decided to
watch the storm behind it. We though that maybe it was being messed with
by the southern storm. Of course, this was not the case. Anyway, our
focus did turn on the southern storm and we shifted south on HWY70/256 to get a
better viewpoint.
We watched the storm from a point about five miles south of
our previous location. At about 18:32 CDT it produced a tornado.
This tornado did not have a condensation funnel, so we watched the ground for
debris. I was on the phone with Lubbock NWS, so they got real time
information about this tornado. The tornado dissipated a few minutes
later. At this point we were pretty happy with the three tornadoes we had
seen. However, we decided to stay with this storm so we shifted south.
During this maneuver the road took us southwest and the vantage point looked
like we were heading into the bear's cage. I really didn't like that idea
too much and strongly recommended we turn tail and run. Rob disagreed, so
we kept going and the road did curve south and south-southeast, as the map
showed. This gave a much different prospective of the implied storm
motion. Our target area was where HWY 70 went south and HWY 256 turned
west. As we got there a tornado formed around 18:40 CDT. This was a
brief tornado, however the circulation center remained after the tornado
dissipated.
The next tornado formed about 18:43 CDT to our west about one
mile. The initial tornado was skinny, basically a rope tornado.
Within a few minutes the tornado grew in size and for a while did not have a
condensation funnel. We followed the tornado as we went north on HWY
70/256. Around 18:52 CDT the tornado took on a "stove pipe" look, also
called an "elephant's trunk." Around 18:55 CDT it took on a "wedge"
appearance, but this only lasted a few minutes. The tornado may have been
at its strongest here. Around 18:57 CDT the tornado decreased in size, to
a point a little smaller than a "stove pipe." It went to rope stage around
19:00 CDT and dissipated around 19:05 CDT.
At this point we were near Brice on HWY 70, where it breaks
off from HWY 256 and goes north. Several other chasers were looking to the
east and we did also. We noted a new circulation center, which is to be
expected after an RFD cycle. This circulation center was just east of us,
so it did cause a few seconds of concern. However, it was not well
organized and move quickly north-northeast. We stayed with the storm for
another 20 minutes as we went north on HWY 70. We decided to break off and
head on home around 19:30 as darkness was close and we didn't have good
storm-scale features anymore. With all this in mind we took a few last
pictures and continued north on HWY 70. We drove into Clarendon and then
continued on north via HWY 70. Reaching I-40 close to dark we noticed what
looked to be a tornado to our north-northwest. We drove over I-40 to look
at it and lost what we were looking at. We're not sure if it was a
tornado.
We did a u-turn and jumped on I-40 east from Jericho.
After a few miles we noticed a lowering to the southeast. We hopped off
and took a few minutes to look at it. After a bit of discussion it was
agreed that we could not determine if the lowered area was a tornado. We
gave it a "possible" tornado label. After a few minutes, it was back to
I-40 east for our crew. A rest stop was near, so we decided to stop and
rest. Apparently people in the facility were quite scared and the tornado
shelters were open. After this brief stop we continued on east and I was
fighting to get data back. I got data back about the time we hit golf ball
sized hail. I noticed a nice looking supercell with a "pork chop"
structure, I then realized we were in that area. Comparing the RADAR to
the GPS map, I noted that we were on the northeast flank of the supercell.
I told David to keep driving, which was strongly protested by both David and
Rob. What I didn't see, until one hit the vehicle, was the baseball sized
hail exploding on impact with the roadway. We took two hits and found an
overpass. We pulled completely off the roadway to be safe and had a few
other people join us. I jumped out to collect some hail stones and as they
stopped falling about that time. I figured the hail had been spit out the
forward downdraft region. I got a phone call which advised me to keep on
moving, so we took off....it didn't hurt that the hail had stopped. We
weren't 20 feet out from the overpass when to our south we saw a lowered area
and an appendage. This sighting accelerated our exit. This was a
situation where we didn't wait around to see what would happen. Rob and I
watched it and can't say for sure what was there. All that mattered was we
didn't stick around to find out.
We stopped in Shamrock and got some gas/food. Back on
I-40 we noticed that westbound traffic was being diverted to the highway.
Not a good sign and we found out later that several tractor-trailers got turned
over. Anyway, it was time to get one home so we continued our trek back to
Oklahoma City. We got home late, so split up and headed home.
Chasers Behaving Badly: Unfortunately on this outing we
ended up in the chase crowd (chase convergence). Roads in the Texas
panhandle are tough to come by, so we cannot spread out. On two occasions
we ended up behind people stopped in the middle of the road. Now, this
isn't a small or dirt road; but a state highway. We got around them and
kept on going. Then had people behind us hooping and hollering. This
isn't our style and rather annoying; especially when you consider that these
things kill people. Unfortunately the people that jump up and down and lay
out a string of cuss words that would make a sailor blush end up on CNN the next
morning. Such as it is, we aren't that way and stir clear of those types.
Lessons
Learned -
- Autofocus: It is on a camera for a reason
and those of us that are novices should make sure it is engaged.
- Cell coverage in the Texas Panhandle is horrible!
- Probably the worst mistake we've ever made. We disengaged from
the storm and lost track of it. Not once did any of us think that we
might meet up with it again. As luck would have it, the "meeting"
didn't have any major consequences other than my windshield. I already
have a lot of battle damage on my car, so a few more hail dents didn't
matter. The new windshield didn't go over at home very well.
However, what bugs me the most is the rookie mistake we made by losing track
of that storm. It was a very stupid mistake and I hope it doesn't
happen again.
Multimedia
Developing Convection, on HWY 256 about 10 east of
Memphis.
Tornado #1 - Southwest of Brice.
Tornado #2 - Southwest of Brice.
Tornado #3 - 5 south of Brice.
Tornado #4 - Near HWY 256/South 70.
Tornado #5 - At HWY 256/South 70.
Photo Gallery: Click Here
Estimated path of #5
Video: Brice
TX - Download Link | Brice TX - Streaming Link |
Running Time Approx 0:4:00
Brice TX "Stove Pipe"
- Download Link | Brice TX "Stove Pipe" -
Streaming
Link | Running Time Approx 0:1:00
In this video some "yAhoos"
pulled up behind up, hooping and hollering. It was not us, the
comment about "violent
tornado" came from them. We're a lot more experienced and
restrained then these
people.
Encounters
-
Engaged
Storm: Near Brice - Storm was near Silverton
Tornado: Yes - 2
Funnel: Yes
Hail (larger than 0.75 inches): No.
Wall Cloud: Yes
Wind (above 57.4 mph): No
Engaged Storm: Storm behind the above one, same locations
Tornado: Yes - 3
Funnel: Yes
Hail (larger than 0.75 inches): Yes - half dollar near Brice and
Baseballs at I-40 MM near 145.
Wall Cloud: Yes
Wind (above 57.4 mph): RFD came close, but probably 40-45.
