April 23, 2003
Storm Chase
SW Oklahoma/NW Texas
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: Enhanced
Moderate - 10% hatch area on tornado prob graphic.
Initial Target Area: Altus, Oklahoma
The mid-level pattern was
characterized by an approaching closed low that was progged to lift into SW
Kansas and wrap up for a few days. At the surface a low was to form in SW
Kansas with a dryline extending south into the central TX/OK panhandles.
Surface moisture was limited in the morning, but progged to improve as the
surface low cranked up during the day. The models had been hinting at
morning convection, which puzzled us a little. They had also hinted at a
lot of overnight convection. We thought that the morning convection was
due to a weak cap and decent jet energy aloft.
Well, sure enough around 08:00
CDT storms developed in western Oklahoma and by 10:00 CDT the dryline fired up
just west of Amarillo. During the day storms continued off and on in
Oklahoma with development ahead of the dryline in NW Texas. Low 60s
dewpoints streamed quickly north and covered areas south of the warm front,
located just north of the Red River. As daytime heating continued, two
supercells developed in NW Texas. Said storms moved eastward, one possibly
producing a tornado in Knox County.
Behind the initial storms skies
cleared and the surface temperature responded. The dryline was still near
the OK/TX border making some progress east. There were indications that
the dryline would refire later in the afternoon. This did not occur as the
upper system wrapped up over SW Kansas, producing little energy along the
dryline. Additionally the dryline started to retreat around 17:30 CDT.
The big problem with today was
the lack of a cap. Several storms did rotate and at least two produced
tornadoes in Oklahoma. A few others apparently produced tornadoes in
Texas. Closed lows aren't the best weather makers and this is case and
point.
SPC Products:
SWO Day 1 Graphics:
Risk Area
-
Tornado Prob -
Damaging Wind Prob -
Hail Prob
Mesoeta 00z Sounding from near
Wichita Falls, Texas
Surface Maps:
Temperature
- Dewpoint -
Wind Speed -
CAPE -
LI
GFS 00z Initialization:
Surface Pressure -
Surface Dewpoint -
500mb Vorticity
The Chase -
Team 1 - David Underwood,
Sarah Davis, and Putnam Reiter
Miles Driven - 350
Departure Time - 12:30 CDT
Return Time - 22:00 CDT
We left Oklahoma City and
headed to Norman to pick up Sarah. We then drove to Lawton via the H.E.
Bailey spur and I-44. Storms had fired in earnest along the dryline, so we
headed on through Lawton. Turning off on Highway 277, we drove towards
Faxon. We zigzagged our way to Vernon, Texas, which was our new target
area. A storm was ongoing at the time, with a much stronger storm to the
south. About the time we reached Vernon the southern storm started to
rapidly weaken. Our storm was already rather weak and we just let it get
on past us.
We decided to move west since
the dryline was still hanging out along the TX/OK border. A few miles west
of Vernon we noted clear skies and warming temperatures. This gave some
hope that the atmosphere might recover. We sat just north of Quanah for a
while watching the dryline try to develop storms. One storm did fire off
in Greer County, which screamed northeast. Around 17:30 CDT we noticed
decaying activity on the dryline. Hearing a tornado warning for Walters we
started that way. However, quickly realized that intercepting it was
futile we stopped and watched the dryline some more. When all the towering
was gone, we packed up and headed to Lawton via Altus.
We stopped in Lawton for a
break and dinner, then headed back to Oklahoma City via Norman on I-44.
While we didn't get much there
were two tornadic supercells in Oklahoma. You had to be very lucky to get
one of them. A KOCO-TV crew got the one near Walters which produced a 2.5
minute tornado. It was rather impressive video, an example of what kind of
day we might have had without early storms. Our problem along the dryline
was that it started to retreat. Once that happens it is game over.
It was still a fun day though and makes us 5-5 on chase days - tornado days.
Lessons Learned -
- Closed lows and weak
caps do not make for good severe weather days. Not only did storms fire
really early, the energy wrapped up around the low and did not punch the dryline
late in the day. The jet max made for more favorable storms farther south
into Texas.
Multimedia -
None
Encounters -
Engaged Storm: None
Tornado:
Funnel:
Hail (larger than 0.75 inches):
Wall Cloud:
Wind (above 57.4 mph):
