May 12, 2004
Storm Chase
Northwest Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: Slight Risk
Initial Target Area: Clinton, Oklahoma
A longwave trof setup over the
western U.S. on Tuesday (05/11/2004) resulting in favorable speed/directional
shear for severe thunderstorms. A week prior (05/02/2004) a strong cold
front moved through the region. Said cold front moved into south Texas and
the Gulf. The resulting cold air advection cleaned out the Gulf.
Return flow quickly re-established itself across the region, however only meager
moisture returned with the surface high still in control of the Gulf. By
Tuesday the surface high moved far enough east (1016mb line was east of the
Texas coast) that true moisture return occurred.
Models forecasted several
shortwave trofs to rotate northeast out of the longwave position Tuesday into
Wednesday. Each of these shortwave trofs gave the incoming cold front a
slight nudge. Models had a real difficult time with the cold front
movement. The Mesoeta was most aggressive with this feature, at one point
taking it into Texas by Wednesday afternoon. Storms developed Tuesday
afternoon along the dryline in the Texas panhandle and in south Texas where a
sub-tropical shortwave trof cause a lot of rainfall and an F1 tornado near
Conroe, Texas. Additionally, a tornado occurred in the Texas panhandle
Tuesday afternoon. After a busy day on Monday (severe tornadoes in
northeast Colorado), Colorado/Kansas were quiet.
Severe weather parameters were
expected to improve Wednesday along and south/east of the cold front. This
feature got pushed southward Wednesday morning as a strong shortwave trof moved
northeast early Wednesday. This caused the surface low to lift out and
turn winds southwest across parts of Oklahoma/Texas. By late afternoon
another surface low was progged to develop in the northeast Texas panhandle
backing the surface winds across western Oklahoma and southern Kansas.
This did occur, but a little later than originally progged. Strong surface
heating occurred across all of Oklahoma and much of Kansas resulting in surface
based CAPE values near 5000 J/Kg and LIs to -10 across the threat area.
Initially helicity values were weak but as the surface flow backed and
low/mid-level flow increase so did the helicity values. The models had
progged about 40kts at 500mb and 60kts at 300mb. Directional shear was
favorable, but speed shear wasn't that great. However, the highly
thermodynamic environment was expected to overcome some of the weaker dynamic
parameters. The elevated mix layer (EML or cap) was quite strong with a
convective temperature of 95F noted in the morning soundings. A
combination of strong surface heating, surface convergence, and subtle lift were
expected to overcome the cap during the afternoon.
At 15:30 towering cumulus
rapidly developed along the dryline in western Oklahoma and surface cold front
in Kansas. SPC issued a tornado watch for northwest Oklahoma and parts of
southwest Kansas about this time. Eventually storms developed along the
cold front and dryline. Also, storms develop in southwest Oklahoma and
northwest Texas, where a severe thunderstorm watch was issued. Severe
storms develop in southwest Kansas and went on to produce tornadoes, including
an F4. A storm developed in northwest Oklahoma, which eventually
dissipated.
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
Soundings: ARPS
Sounding -
OUN -
ICT
Mesoeta 00z Initialization:
Surface Pressure -
Convective Inhibition
-
0-3km Helicity
-
850mb Temperatures
-
850mb Dewpoints
-
850mb Windspeed -
850mb Vertical Velocity
-
700mb
Wind -
700mb Temperatures
-
700mb Relative Humidity -
700mb Vertical
Velocity -
500mb Vertical Velocity -
500mb Temperature -
500mb
Vorticity -
500mb
Wind
-
250mb Wind
The Chase -
Team 1 - Ray Hardy, Rob
Ferguson, and Putnam Reiter
Miles Driven - 450
Departure Time - 13:30
Return Time - 22:30
This is one of those summaries
I'd rather not write. However, it is good from a learning perspective and
hopefully indicates to the casual reader what a tough hobby this can be.
We left Oklahoma City around
14:30 and headed west on I-40. We thought about Watonga or points west but
wanted to play the instability max located in southwest Oklahoma. We knew
that southwest Kansas was most favorable from the SPC outlooks and our own
forecasting. However, we really didn't want to travel all the way up
there. We exited at Clinton and filled up real fast. The cumulus
field was flat and not impressive. The back-edge was about at Clinton when
we got there. This was rather discouraging to us.
We went north out of Clinton on
Highway 183. After a few minutes of driving north we noticed towering
cumulus to our west. We drove north to Taloga and a little north from
there. We turned west on Highway 60 for about six miles. Since the
atmosphere was still getting things together we set up the chase vehicle.
There wasn't much to watch, other than the towering cumulus. About 16:50
we decided to head back to Highway 183 and drive north. While we though
the towering cumulus looked good in our area, stuff to the north looked much
better. We heard of storm development in Kansas a little bit later and
thought our area would go next. By 18:00 it seemed that our area wasn't
going to break the cap, so we set out to Alva.
Heading north on Highway 183,
which turned into Highway 281 we traveled north watching the sky conditions
around us. The cumulus would come together briefly and then dissipate.
After stopping in Waynoka for a few minutes, we went east on Highway 281 along
with a few other chaser. We followed this road north towards Alva.
We could see the storm in Kansas which had a solid back edge and inflow
features. As we got north a little I noticed a storm to our south.
After conferring with RADAR we turned around and went for it. We took
Highway 11 east and to Highway 8 south, heading for Cleo Springs. The
storm was near Fairview and moving east-northeast at about 20mph. As we
got to the storm it was about 19:30 and we knew sunset was about an hour away.
The storm was real small and had an LP look to it. We went east on Highway
60 as it was just to our west. We watched what was essentially an updraft
base and almost no precipitation. Periodically the storm would produce
rain and/or hail but that was about it. By 20:00 the storm had completely
dissipated. Quite upset and annoyed we headed east to Enid for food.
We then took Highway 81 south to Highway 33 east in Kingfisher. Then on
back to Oklahoma City via Highway 74.
The question we keep asking
ourselves is why we turned around. The main answer seems to be that the
storm near Fairview was more in our chase area. There are good and bad
reasons to have a specific chase area. Apparently we weren't the only ones
on this storm but probably the one people to leave the Kansas activity.
The Kansas storm went on to produce several tornadoes, including an F4.
The video has been seen on the news channels the past few days.
Thanks for Andy and Jay for
data support.
Lessons Learned -
- Not sure this is much I
can say here without getting in trouble by the group. Our forecasting was
great, per usual, however we just couldn't connect while out. Obviously
the pain from this day is enhanced by what an awful season 2004 has turned out
to be. We will probably use a secondary chase target in the future.
This hopefully will keep us from having tunnel vision.
Multimedia -
Video (Requires Microsoft Media
Player 9.0 or newer):
-
Webcam
2.9MB
-
Vance RADAR
10.0MB
Stills:
- Rob and I setting up
the vehicle.
Pic 1
- Towering Cumulus.
Pic 1,
Pic 2
- Storm in Kansas.
Pic 1
- Storm by Fairview.
Pic 1,
Pic 2,
Pic 3
Encounters -
Engaged Storm: Fairview,
it dissipated fast.
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: No
Wind (above 57.4 mph): No
