March 4, 2004
Storm Chase
Central Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: High Risk
Initial Target Area: Ardmore, Oklahoma
This forecast was a tough one
from the word "go." The forecasting elements did a great job with the
system, SPC was at the top of their game. Given how complex the evolution
was, potential certainly existed for more significant severe weather. That
is not to take away from the 91mph wind report in Wichita Falls.
Today was the best severe
weather setup since May 16, 2003, for Oklahoma. A closed low was progged
to dig to near Baja and then quickly move northeast into southwest Texas early
Thursday. This system would then continue to quickly move northeast as a
negative tilt trof during the day and reach the northern Texas panhandle by
evening. Model progs remained pretty consistent with the 500mb pattern and
associated dynamics at various atmospheric levels. The tough part of the
forecast related to surface features, specifically the warm front and
precipitation. The Mesoeta consistently progged the warm front into the
I-44 area by Thursday morning with low/mid 60s dewpoints across much of Texas
and southeast Oklahoma. This model also placed the most precipitation in
near and northwest of I-44. The GFS varied a little, but essentially had
the same surface pattern. It did hit precipitation really hard in
southeast Oklahoma.
Models also had a lot of
precipitation occurring in the warm sector on Wednesday into early Thursday.
Much of this precipitation did not occur. There were showers across parts
of Texas early Thursday, but the main limiting factor was extensive cloud cover.
Even though surface heating was a concern, decent instability was still progged
across OK/TX per steep lapse rates. This coupled with a strongly sheared
environment and upward forcing certainly pointed to a widespread severe weather
event.
A squall line developed around
mid-morning across western Texas as the upper system impinged on the region.
The surface low started moving north-northeast by noon. The squall line
started moving quickly east across Texas and moving northeast into Oklahoma.
As the line of storms moved into Oklahoma strong winds were noted across
southwest sections. The storms also produced strong winds across
south-central Oklahoma and a tornado near Muldrow. Texas experienced the
brunt of this system with numerous high wind and tornado reports.
SPC Products: SWO
Day 1 Graphics:
Risk Area
-
Tornado Prob -
Damaging Wind Prob -
Hail Prob -
Storm Plot -
PWO
Surface Maps:
Temperature
- Dewpoint -
Wind Speed -
CAPE -
LI
Mesoeta 00z Initialization:
850mb Vertical Velocity -
700mb Vertical
Velocity
-
700mb
Wind -
500mb Vertical Velocity -
500mb Temperature -
500mb
Vorticity -
500mb
Wind -
250mb Relative Humidity
-
250mb Wind
The Chase -
Team 1 - David Underwood and
Putnam Reiter
Miles Driven - 80
Departure Time - 13:15 CST
Return Time - 20:30 CST
We had plans in Ardmore, so
this is not necessarily just a chase. Since conditions looked good for
some storm activity in Oklahoma, despite the extensive cloud cover, we decided
to head out before going to Ardmore.
We left Oklahoma City and
headed south on I-35. Monitoring RADAR we noted the northeast moving
squall line as it moved into the state. Amateur radio reports confirmed
strong winds and damage with this line. Initially we thought that
Chickasha would be a good spot to end up, however we were way passed the HWY 9
connector at this point. So, we headed on south via I-35 and intended to
exit at Purcell and go west. We stopped at Purcell to setup the Scout and
then head on west. Shortly after we realized that we were on HWY 74
southbound and not HWY 39. We stayed southbound through Maysville on to
Elmore City. At Elmore City we turned west on HWY 29. We continued
west until we started into strong winds and rain. This prompted us to stop
at the HWY 39 and HWY 76 intersection. Sitting here for a few minutes we
watched the line pass over us and noted some some curvature to the back-edge of
the storms. Given that embedded supercells were possible, we followed this
feature north. We went north on HWY 76 and watched as this feature quickly
moved to the northeast. It looked interesting enough, but didn't get to
the wall cloud stage or do much more than what we say initially.
Coordinating with Mark Hill we learned that he had filmed a few brief touchdowns
near Duncan. Since we were northeast of his location, we probably
intercepted the rotation area that he had been monitoring.
Storm motion was about
50-60mph, so it was tough to keep up with the line. We decided that it was
time to head on to Ardmore and complete the day's tasking. At Lindsay we
turned east on HWY 19 and took it through Maysville on to Pauls Valley.
That pretty much ended this chase for us.
Lessons Learned -
- No major problems this go
around, everything seemed to work fine. The biggest problem was our
navigation error at Purcell. It did work out for the better, which may
raise a concern about forecasting.
Multimedia -
- None
Encounters -
Engaged Storm: HWY 39 and
HWY 76 Intersection
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: No
Wind (above 57.4 mph): Maybe, but nothing that we measured.
