March 27, 2004
Storm Chase
Western Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: Slight Risk -
16:30z
Initial Target Area: Hobart, Oklahoma
Recent model performance has
been less than optimal. At the beginning of the week the GFS showed a
longwave ridge over the central U.S. A longwave trof was progged to
traverse into Colorado and then move north to North Dakota. Around
Wednesday the GFS changed its tune to a more progressive system with a less
amplified ridge. The Mesoeta shortly followed with the same pattern.
By the 12z model runs Thursday morning, the models agreed on the basic pattern,
increasing forecast confidence. The usual changes occurred from run to
run, but nothing that was difficult to get past. The models handled
western Oklahoma morning convection well and the evolving thermodynamic profile.
The negative was model handling of the 700mb temperatures. The GFS and
Mesoeta consistently under-estimated the 700mb temperatures. Several runs
of the Mesoeta progged the cap to completely erode by 6pm Saturday across much
of western Oklahoma. This did not occur, as evident by the convective
inhibition map below.
This setup had a longwave trof
moving eastward into Oklahoma/Kansas while taking on a slight negative tilt.
A surface low was progged to be in SW Kansas and slowly weaken during the day.
The associated surface dryline extended southward from the low across the western
Texas panhandle. Low 60s dewpoints extended from central Texas northward
into southern Kansas. The primary concerns for storm initiation were
overnight convection and cloud cover. The cloud cover was a concern even
if overnight storms did not develop. March sun angle is not enough to
erode stratus and/or cirrus. Additionally, if numerous storms developed
overnight debris clouds may be left across the threat area. Models
consistently hinted at convection on the edge of the 50kt low level jet early
Saturday morning.
Storms did develop Saturday
morning across parts of west Texas and the eastern Texas panhandle. This
activity moved east into western OK by 10:00am and then on east out of the
threat area. The convection acted to clear skies across the Texas
panhandle into parts of western Oklahoma and SW Kansas. By noon the
dryline was located along the Texas/Oklahoma border. Isolated storms
started to develop on the dryline and move east by early afternoon. A
tornado watch was issued by SPC for western Oklahoma northward into
south-central Kansas around 12:45pm. Three supercells eventually developed
in Oklahoma. The first one, near Vici, produced a rather photogenic
tornado. The next supercell developed in Beckham County and moved
northeast to Elk City and eventually north of Watonga. This storm produced
a brief tornado just west of Thomas. The final supercell developed near
Mangum, just west of our original target, and moved northeast to Okarche and on
into Payne County. This supercell produced a small tornado near Okarche
around 18:45.
Forecasting for this event was
less than stellar. Mike Morgan (KFOR-TV OKC) gets the award for best
forecast this go around. Frank Johnson (KOCO-TV OKC) stated Friday
night that tornadoes were not expected on Saturday. Our forecasting went
well this period. To have a storm develop near our target is awesome to
us.
SPC Products: SWO
Day 1 Graphics:
Risk Area
-
Tornado Prob -
Damaging Wind Prob -
Hail Prob -
Storm Plot -
LSRs
Surface Maps:
Temperature
- Dewpoint -
Wind Speed -
CAPE -
LI
Mesoeta 00z Initialization:
Convective Inhibition -
0-1km Helicity
-
0-3km Helicity
-
850mb Temperatures
-
850mb Dewpoints
-
850mb Windspeed -
850mb Relative
Humidity -700mb Vertical
Velocity
-
700mb
Wind -
700mb Temperatures
-
700mb Relative Humidity -
500mb Vertical Velocity -
500mb Temperature -
500mb
Vorticity -
500mb
Wind -
500mb Relative Humidity -
250mb Relative Humidity
-
250mb Wind
The Chase -
Team 1 - Andy Wallace,
Ray Hardy, Rob Ferguson, and Putnam Reiter
Miles Driven - 353
Departure Time - 12:45 CST
Return Time - 18:30 CST
Andy drove up from Waco
Saturday morning to chase with us, a continued testament that we thought one or
two tornadoes would occur. After picking up Ray and Rob, we three met up
with Andy at my house. Time was around 12:30 and we decided to get moving,
given storm development on the dryline and the recent MCD from SPC.
Attempting a quick stop by Braum's so Andy could eat, we sat up the computer
equipment. Having to abort that eating spot we jumped on the road when the
tornado watch was issued. We headed west on I-40, gathering data as we
went.
We tried for another eating
spot for Andy and got lucky this time. It also allowed us to fix a
computer problem. Radar indicated that a storm had moved into Beckham
County and was moving northeast at about 25-30mph. This seemed like a good
storm to start with and we could continue to monitor for development farther
south along the dryline. We also heard of the
storm in Vici. Knowing that Vici was too far, we did not worry about that
storm. Continuing west on I-40 we exited at Foss (MM 53) and turned north
on Highway 44. Visibility was good and we immediately had storm-scale
features. Several lowerings were noted as we drove north a few miles on
HWY 44. We turned west on a country road and stopped about a mile down the
road. Here we watched the storm as it approached. The storm had
decent low-level features, but no consistent low-level rotation. We turned
back east to HWY 44 and went north to the south edge of Foss Lake. We sat
there for about 15 minutes watching the storm. Several attempts at wall
clouds were noted. The storm ended up east of us, so we headed north on
HWY 44 to Butler. We wanted to avoid the hail core, so we let the storm
get on northeast a little bit. Once in Butler, we turned east on HWY 33.
We watched the back-edge of the storm cross the highway. We spotted mostly
nickel sized hail and some golf ball as we drove east for a few miles. We
then encountered larger hail and measured one stone at 2.5 inches. We
turned north on HWY 183 and then back east on HWY 183 through Custer City.
At this time we were just following along with the storm watching it cycle.
We tried to stay on the southeast flank, which was not that tough. HWY 33
take a northeast turn and that helped us stay with the storm. We stopped
just southwest of Thomas when we saw a funnel. The storm produced a brief
tornado around 15:30. It looked more like a landspout than a tornado.
We then followed the storm on northeast to just east of Fay. At this point
our radar support and visual observations indicate this storm was weakening.
Additionally, a storm near Mangum was showing decent potential.
We headed south on HWY 270 from
Watonga. When we reached I-40, we drove west to Hydro (MM 88). The
Mangum storm was near Bessie and it had great visibility. This storm
exhibited LP supercell characteristics, which made for great viewing even 20
miles away. As we got close to the storm, we saw some low hanging clouds.
After turning south on HWY 58 for a few miles, we stopped and watched the storm.
We noted several rotation areas, but none of them formed anything threatening.
The storm seemed to have a tough time organizing. We sat with this storm
for a good thirty minutes before deciding to pick up and head home. Radar
indicated that the storm was disorganized and not much of a threat. We
drove east on I-40, stopping at HWY 270 to break down the chase equipment. The
storm started to look better organized, but we decided to keep on heading back.
This storm did produce a brief tornado south of Okarche, similar to what we
witnessed near Thomas. We got back into Oklahoma City around 18:45 and
everyone went home.
This certainly was a great
outing for us. We got to test a lot of new equipment and have fun along
the way. Also, we feel very good about our forecasting this go around.
The whole group wishes to express our sincerest thanks to Jay for all the radar
support.
Lessons Learned -
- This is tough as I
cannot think of any lessons learned right now. About the only one is the
fact that the other three guys didn't throw me out of the vehicle for being
uptight. We're still looking over the video and looking for learning
points there. The most notable thing is to monitor a storm before calling
"tornado." Exceptions to this are obvious, but low hanging clouds in the
updraft region do not infer a tornado when you're ten miles away.
- This one from Brad: Place a coin or some known measured element
next to a hail stone when taking pictures.
Multimedia -
Pictures -
- Storm west of Foss -
Picture 1
- 2.5 inch Hailstone -
Picture 1
- Tornado just west of Thomas -
Picture 1,
Picture 2
- Storm southwest of Hydro -
Picture 1,
Picture 2,
Picture 3,
Picture 4
Video -
-
Webcam Pics - This is an animated GIF of the
pictures taken by our web cam as we chased. The GIF is about 3.98 MB and
takes 90 seconds to loop. Please note that the GIF will loop until you
close the viewer.
Encounters -
Engaged Storm 1: Foss
Lake
Tornado: Yes - 2 west of Thomas
Funnel: Yes
Hail (larger than 0.75 inches): Yes - 2.50 inches, 4 east of Butler
Wall Cloud: Yes
Wind (above 57.4 mph): No
Engaged Storm 2: South of
Hydro
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
