April 25, 2009
Storm Chase
West-Central Oklahoma
Editor: Putnam E. Reiter
Forecast/Setup -
Risk Area: Moderate Risk
Initial Target Area: Sayre, Oklahoma
SPC Products:
SWODY1
16:30z -
Risk
Area -
Tornado Prob -
Hail Prob -
Wind Prob -
LSR Plot
-
LSR
GFS 00z Initialization:
Surface Pressure
- Dewpoints -
CAPE
- MLCAPE
- CIN
-
Surface Temperature
-
850mb Dewpoints
- 850mb Wind
-
850mb UVV -
700mb Wind
- 700mb Vertical
Velocity -
700mb Relative Humidity
- 500mb Temperature
- 500mb Wind
-
500mb Vertical
Velocity -
500mb Relative Humidify
- 500mb Vorticity -
250mb Wind
- 250mb Relative
Humidity -
00z Norman Sounding
SPC Case Review
After a cool and very active April, we finally got a
setup where moisture would be available. A big
problem this month has been the closed lows moving
eastward in the southern stream. These systems
have not been favorable for Oklahoma and typically
resulted in strong cold fronts pushing moisture well
into the Gulf.
This setup was a little different in that Gulf
moisture would have time to return ahead of the
dryline. Warm afternoon temperatures would
yield CAPE values in the 2500 J/Kg range.
Quite sufficient for severe thunderstorms given
veered flow aloft and seasonable speeds. The
western U.S. was still developing on this day, but
enough flow aloft and surface moisture indicated
potential for severe thunderstorms. SPC's Day
1 outlook looked good and things seemed pretty clear
cut for western Oklahoma.
We knew that there were two areas of interest, the
first along the dryline, which was progged to be
near the TX/OK border attached to a surface low near
Pampa. A cold front was progged to drift into
northwest Oklahoma and the panhandles during the day
and stall. It did so and started retreating
north by late in the day. This was the
secondary area for storm development. We
decided to play the triple point, as did almost all
other chasers.
The first storm developed in the Texas panhandle,
north of I-40 (Shamrock). This storm moved
quickly northeast and into Oklahoma. Most of
the chasers headed to that storm. Additional
storms formed in far western Oklahoma and moved
northeast. The storms were elongated
east-southeast to west-northwest as they moved
northeast. The exception was the lone
panhandle storm, which had more of a classic
supercell look. The storms stopped developing
in southwest Oklahoma around 7pm and moved north of
I-40 at Weatherford by 10pm.
Storms continued into the nighttime hours with one
producing a tornado north of Enid around 10pm.
Another storm moved into the same area and produced
a tornado in Kremlin around 2am. Only a few
injuries from these tornadoes and minor ones, very
lucky.
The Chase -
Team 1 - David
Underwood, Rob Ferguson, Brett LaBare and Putnam Reiter
Miles Driven - 336 - Gas spent $20.00
Departure Time - 14:00 CDT
Return Time - 22:00 CDT
Track Path
We left Oklahoma City and headed out west on I-40.
We got to Elk City and dropped by Walmart to fix our webcam issue. Getting
that fixed we headed to McDonald's for some food. During all of this the
storm in the Texas panhandle developed and we decided to hang out and watch it.
After getting done at McDonald's we noticed a storm had rapidly developed
southwest of us. Seeing this as a good opportunity, we headed south on HWY
6 to HWY 55 and went west a few miles. We sat here and watched the storm
develop. Not seeing anything significant with it, we just waited.
Eventually the storm go far enough north, we decided to drift back to HWY 6 and
go north.
As we headed back north to Elk
City we knew road options were going to be a
problem. We'd have to risk getting close with
the storm to stay on the good roads. So, we
drove up to I-40 and went east to HWY 34 and went
north. We sat just north of Elk City and watch
the storm. We sat here for about 5-10 minutes,
not really noticing anything significant with the
storm. Seeing it getting away again, we
drifted north and had to go east on a section line
road. About this time we saw a new RADAR image
where 65dbz was located ontop of us. About the
same time we started getting dime size hail.
Our only option was to get east and out run the hail
core. We did so and ended up getting some
nickel hail. We finally got far enough east
were we could turn around and watch the storm.
It had a lowering, but nothing really that
impressive.
We drove into Foss and sat there
to decide what our options where. The other
storms looked like ours, so there was seemingly no
need to go elsewhere. We went north on HWY 44
to HWY 73 and went east. At this point we met
up with all the other chasers on this storm.
We stopped a few times on HWY 73, but in general
were not impressed with the storm or structure.
Getting on the west side of Clinton we stopped and
watched the storm and the other storm coming up from
the south. We certainly thought a cell merger
was going to occur. We waited a little long
and decided to get east on business 40.
Getting on the east side of Clinton we stopped at
MM74 to evaluate our options. Here we had a
great view of the storm north of Cliinton and the
one to the south.
After watching the storms for a
while, we decided to head south on Custer City Road
and get a better look at it. We didn't have to
go very far south and we saw the business end.
Turning west on a private road, we parked on a hill.
The storm had a real high base, but a definite
rain-free base. As we sat there the storm
appeared to low the base and developed a wall cloud.
Upward motion was good, but differential wasn't so
good. We started back east and then north to
keep up with the storm. He had another issue
with roads here as getting north of I-40 would be a
problem road wise. So, we got to I-40 and went
east. The storm started to lose its features
as we went east on I-40. Getting just east of
Weatherford we pulled off to get a look at the
storm. As with the other storms, it didn't
look impressive for long.
Seeing two final storms moving
towards us, we headed back to HWY 54 and went south
from Weatherford. We drove south to HWY 152
and went west a few miles. We sat at HWY 54
south (you gotta know Oklahoma Roads to understand
the 5 mile split) and watched the storms. It
was night time and we didn't have much storm
structure. Even what we did see, RADAR didn't
show anything impressive. In fact RADAR showed
about what we had been seeing all day. While
we had pledged to chase at night, this just wasn't
worth it.
Having had a decent day, we
decided to head home. We went back east on HWY
152 to HWY 58 north, then east on I-40 to Oklahoma
City.
I have no real complaints this
this chase. I should have looked more at the
midlevel winds and probably would have noticed why
the storms were elongated. Either way, it was
a good day for storms and we did a great job
following them once we committed.
Lessons
Learned -
- Nothing really here. We got cored once, but
managed to get east. Unfortunately this day did not go as expected,
the best action was well after dark.
Multimedia
-
Photo near Clinton -
1
Oklahoma City RADAR -
WMV Format - this is 11MB but is a 16 hour loop.
Encounters
-
Engaged
Storm: Carter to Clinton
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): Yes - estimated nickel
Wall Cloud: Yes
Wind (above 57.4 mph): No
Engaged
Storm: Clinton
Tornado: No
Funnel: No - ehh maybe
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
Engaged
Storm: Cordell - actually two storms here.
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: No
Wind (above 57.4 mph): No
