April 19, 2003
Storm Chase
Eastern Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: Enhanced Moderate
for eastern Oklahoma - 10% hatched area on tornado prob graphic for
southeast Oklahoma.
Initial Target Area: South-Central Oklahoma - Ardmore
Shortwave trof was progged to lift east-northeast during the afternoon, reaching
central Oklahoma by 7:00pm. Overnight convection seriously complicated the forecast as a large area of
showers and severe thunderstorms
developed near Lubbock and moved into central and northeast Oklahoma overnight. Clouds quickly cleared
across central/western Oklahoma Saturday morning, allowing for strong surface
heating. The models had been progging the dryline to punch eastward to near I-35 by afternoon with a bulge
near central Oklahoma around
this time. We had a hard time going with the forecast, but it verified. The
models did a pretty darn
good job on this event.
There were a lot of boundaries floating around in eastern Oklahoma. An outflow
boundary was located near I-40
that intersected with the dryline in east-central Oklahoma. Storms initially
developed across northwest
Oklahoma and then around the dryline bulge in north-central Oklahoma southeast
to east-central sections. Eventually storms formed south to near Durant.
We originally picked Ardmore as a balance between thermodynamics and dynamics. We figured that the best
heating would be in southern Oklahoma and Texas. As we drove to Chickasha to
pick-up Andy, we noted
strong towering cumulus along the dryline bulge. This convinced us to change our
minds and we ended up
moving east to near Shawnee.
SPC Products:
Day 1 -
Watches -
MDs Graphics:
Day 1 -
Tornado Prob -
Wind Prob -
Hail Prob
Local Storm Reports -
Warnings/Mesoscale Discussion from
Tulsa
Surface Plots:
Temperature
-
Dewpoint -
Pressure/Wind Speed -
CAPE -
LI
GFS 00z Initialization
Surface Pressure
Surface Dewpoint
Precipitable Water
850mb Wind
850mb Dewpoint
700mb Wind
500mb Wind
500mb Vorticity
300mb Wind
250mb Wind
The Chase -
Team: Allen Wright, Andy
Wallace, Steve Clary, and Putnam Reiter
Miles Driven: 505
Departure Time: 12:20 CDT
Return Time: 23:00 CDT
We left Oklahoma City and headed southwest to Lawton to pick up Andy. Noting the
strong towering
cumulus to our north and east, we convinced Andy to meet us in Chickasha. We
thought seriously about
going to Ardmore and then moved it to Pauls Valley and then to Purcell. The
target area kept moving north
as we watched the clouds form and noted a distinct lack of strong development to
the south.
Picking up Andy around 14:00 CDT we headed back north on I-44 and took the I-35
south bypass to Norman. We went east on Highway 9 towards Shawnee. The cloud field directly in front of
us continued to enhance
and storms looked to be forming. About this time SPC came out with a PDS tornado
watch for much of
eastern Oklahoma. We wanted to get up to I-40, so we could move east faster. The dryline and associated
development was still moving rapidly east at this point.
We caught the storm on I-40 just east of Shawnee. Noting a nice rain free base,
we slowed down to stay
with it. Other development was noted to our south, however this storm had a
difficult time forming and
most likely got absorbed into the northern storm. We exited I-40 at Highway 56
and turned north. This road
took us a little bit north and then east. We then turned north on Highway 46 and
took it just north of Castle. This is where we saw our first and brief tornado at around 15:50 CDT. We stayed
with this storm, zigzagging
on dirt roads and eventually got back on a paved road near Slick, which was
Highway 16. We took this east
towards Beggs. We turned north on 75A, noting several wall clouds. Hills and
trees kept us from seeing
if surface contact ever occurred. Several reports of tornadoes were reported
just south of Mounds. We
turned east just south of Mounds to jump over to Highway 75. We then took that
north to Highway 67 east to
Bixby. The storm tried several times to produce a funnel, but just couldn't spin
up the circulation.
About this time we noted the storm was losing its features and taking off from
us. These observations were
shortly confirmed by the Tulsa NWS Office noting that the storm had weakened
considerably.
We thought about heading home and then noted the honker to our north. Our storm
was a low-topped classic supercell much of its life. However, the storm to the north had an anvil and a
back sheared anvil. We
decided that it would be worth the effort to go take a look. Getting around Tulsa
we jumped on Highway 75
to Bartlesville. We knew that the storm was near Pawhuska and decided to just
stay going north on 75. I
wanted to turn west several times, but storm motion meant that we didn't have
too. We rolled into
Bartlesville around 18:10 CDT. We ran through Bartlesville as fast as traffic
and stoplights would let us. We then got just south of Dewey and noticed intense circulation to our north. We
watched it cross the
road and then continued north about 3-4 miles. As we approached an east option
we noticed power lines and
trees were down for about 100 yards. Turning east on W 1100 we notice damage to
homes and a maintenance
building. Two-three of the homes had been destroyed with major/minor damage to
several other homes. A quick
call to the NWS in Norman to report this and we headed on east.
The storm was moving northeast, so we zigzagged with it a little. We stayed on
W 1100 for a while as we
noted a circulation just to our north. We looked a little west and noted what
was probably the tornado. It
appears that this tornado was a long track, at least five miles. We filmed it
for a while and then it
dissipated. Several RFD structures were noted during the life cycle of this
storm. We reached Highway 169
and turned to South Coffeyville, Oklahoma (just on the OK side of the OK/KS
border). We drove east for a
little bit and decided to end the chase as it was near 20:00 CDT, the storm was
getting away from us, and
it really looked like the storm was done.
We headed back west on Highway 10, noting damage just east of Wann. This must
have been where we saw the
tornado dissipate and also why we think it was a long track. As we drove back to
Highway 75 at Copan, almost
all of the section line roads had been closed off by law enforcement. Additionally, we drove south on
Highway 75 out of Copan, noting the same thing. We got back to the damage path
on Highway 75 north of Dewey
where quite a congregation had developed. We didn't get great video of the
damage, but our first time by must
have been right after the tornado.
After getting some fuel, we headed back to Tulsa on Highway 75. We had a quiet
dinner and drove back to
Oklahoma City. Everyone took off and headed home at this point.
We're pretty happy about this chase. So far this year has been great for us, we
are 4-4 on chase days-tornado days.
We finally got to make-up for the first few chases this year and nab two
tornadoes.
The multimedia clips are
between 4-8 MB, we try to scale them down a little. However, reducing them
too much takes away from the video big time. They are much better over a
cable modem/DSL connection or better.
Lessons Learned -
- Storm motion was a bit
difficult, but didn't cause any major problems.
- We got tunnel vision on our storm near Dewey. It was an LP supercell,
which we didn't pick up on soon enough. The lack of observation only
caused us to miss the tornado for a little bit, however it can also cause you to
end up dead.
- Changing pre-convective environment was the biggest issue. On further review
the storm near Pawhuska head
a 2000 J/Kg CAPE max to its south.
Multimedia -
-
Clip 1 - Brief tornado,
looking north, southwest of Slick about 10 miles.
-
Clip 2 - Funnel and then RFD, in Dewey, looking north.
-
Clip 3 - Damage path, 3 miles north of Dewey.
-
Clip 4 - Tornado, looking northwest towards Wann.
Encounters -
Engaged Storm: Southwest
of Slick, Oklahoma
Tornado: Yes
Funnel: Yes
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
Engaged Storm: Dewey,
Oklahoma
Tornado: Yes
Funnel: Yes
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): Yes - RFD probably 60mph.
