April 30, 2004
Storm Chase
Central Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: Slight Risk -
Oklahoma, Moderate North Texas
Initial Target Area: Ardmore, Oklahoma
Another strong cold front moved
through the region the prior Saturday (4/24) and pushed moisture well off the
Texas Coast. A longwave ridge developed across the western U.S. as a
shortwave trof moved southward on the downstream side of the ridge. The
models had a tough time with the upper system, some closing it off and others
remaining progressive. The end result was something in between. On
Thursday decent low-level moisture returned to parts of Texas and southern
Oklahoma. While mid-level winds were somewhat weak, a shortwave trof was
expected to move across the region at peak heating. Storms developed along
the dryline Thursday afternoon, with a squall line developing by 7pm. A
MCS also developed, which moved eastward across Oklahoma and parts of north
Texas. This MCS helped the synoptic cold front move south and end up from
Wichita Falls northeast to Tulsa by Wednesday afternoon.
Morning clouds held tough
across the region, however by early afternoon the atmosphere rapidly recovered
from the overnight convection. The cold front was moving slowly south and
might have stalled for a period of time. Part of north Texas and southeast
Oklahoma warmed into the 70s with CAPE values above 2500 J/Kg. Two lone
storms developed near Wichita Falls by 1:00pm and moved slowly northeast.
A little later several other storms develop along the dryline to near Abliene.
A line of storms eventually developed across north Texas. A confirmed
tornado occurred near Abliene while a few brief tornadoes occurred in southern
Oklahoma.
Farther north a brief storm
developed near Paul's Valley and moved northeast, this storm was quickly
undercut by the cold front. It didn't last much longer than 45 minutes.
Another storm developed near Chickasha and split with the right split weakening.
The left split moved north-northeast and produced 3.0 inch hail in Piedmont.
Many of the storms were
supercells but like the prior events, too many storms developed. The Fort
Worth convective temperature was 77F. This allowed widespread storm
initiation with little tornadic activity.
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
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 -
500mb Relative Humidity -
250mb Relative Humidity
-
250mb Wind
The Chase -
Team 1 - Aviva Braun,
David Underwood, Rob Ferguson, and Putnam Reiter
Miles Driven - 200
Departure Time - 14:30
Return Time - 18:00
We left Oklahoma City and went
south on I-35. Our original target area was Ardmore or a little farther
south. Our thinking was to intercept the activity moving east from Wichita
Falls. As we got south of Paul's Valley Rob noticed towering CU to our
northwest. A quick look at RADAR showed a few 20dbz echoes in this area.
We stopped at Highway 17A to take a look. We sat here for a while and then
decided to follow the storm. The next RADAR update showed a 50dbz core.
We went west of 17A to Highway 77 and went north into Wynnewood. We turned
east on Highway 29.
Seeing that we needed to get
north some, we turned north on a county section road, which turned into state
highway 123. We drove north for a little bit and stopped to watch the
storm. It had decent low level features and a wall cloud. We drove
just north of Highway 29 and watched the storm. About this time the cold
front had undercut the storm and the low level features rapidly weakened.
Eventually the storm completely dissipated as the cold front was about 10 miles
south of us at this point.
We drove east on Highway 29
hoping for more development on the cold front. Not being able decide
between that route and going to Ardmore, we decided to head home. Storms
failed to develop farther north on the cold front, so that turned out to be a
good call. We drove back into Paul's Valley and north on I-35.
Lessons Learned -
- Nothing noteworthy here, we
probably should have looked at the cap (EML) strength a little more. Once
we intercepted the storm, things went well. Also, late April cold front
storms rarely end up good.
Multimedia -
- We got some pictures of the
Paul's Valley storm and the hail in Piedmont, about 40 minutes after the event.
These should be posted soon.
Encounters -
Engaged Storm: South of
Paul's Valley
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
