April 26, 2009
Storm Chase
Southwest Oklahoma
Editor: Putnam E. Reiter
Forecast/Setup -
Risk Area: High Risk
Initial Target Area: Altus, Oklahoma
SPC Products:
SWODY1
16:30z -
Risk
Area -
Tornado Prob -
Hail Prob -
Wind Prob -
LSR Plot
-
LSR
NAM 00z Initialization:
Surface Pressure
- Dewpoints -
CAPE
- MLCAPE
- CIN
- 0-3 Km Helicity -
Surface Temperature
-
850mb Dewpoints
- 850mb Vertical Velocity -
850mb Wind
-
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 -
12z -
18z -
00z Norman Soundings
SPC Case Review
The main difference between yesterday and today was
the expected approach of a shortwave trof into the
region. Wind speeds were expected to improve
with decent instability. A concern was model
progged development of widespread showers and
thunderstorms across the threat area during the
morning hours. This did not occur as only
isolated development happened. A bigger
problem was the widespread clouds across the region,
which kept CAPE values around 2500 J/Kg or lower.
Another issue was moisture mixing out in Texas,
which lowered CAPE values in this area.
Storms developed by noon and a tornado watch was
quickly issued. These initial storms
dissipated with little coverage. Other
development continued along the warm front in far
northwest Oklahoma. By mid-afternoon, clearing
occured in the western Texas panhandle. CAPE
values rapidly jumped into the 2500-3000 J/Kg range
and a severe thunderstorms quickly formed.
This storm moved into northwest Oklahoma and
produced several tornadoes. It was a strange
storm structure was elongated cores and cell
mergers. Either way, lots of chasers got these
tornadoes on video.
In southwest Oklahoma, a severe thunderstorm moved
northeast from Texas into southwest Oklahoma.
This storm continued moving northeast and produced
tennis ball hail in Texas. It tried to produce
a tornado near Snyder but lowered CAPE values from
Texas likely prevented such. It eventually
moved into Canadian County where it lost its
structure and become part of an MCS.
Other storms developed along the dryline in
northwest Texas and moved into far southwest
Oklahoma. There were numerous storms on this
line and they likely interfered with each other.
These storms attempted to remain supercellular but
eventually became part of the growing MCS.
The Chase -
Team 1 - David
Underwood, Rob Ferguson, Brett LaBare and Putnam Reiter
Miles Driven - 300 - Gas spent $24.00
Departure Time - 14:30 CDT
Return Time - 21:15 CDT
Track Path
We left Oklahoma City and headed southwest on I-44, reaching
Lawton we went west on HWY 62 to Altus. We got to Altus and got some food
and hung out at the Holliday Inn. We watched RADAR, seeing the storm to
our south and the storms up northwest. Knowing that we could not get to
the storms northwest, we decided to focus on the storm to our south. This
storm was well established and was moving into Oklahoma. If we waited it
out, we would be able to fall in right behind it. We also noted the storms
to our southwest, but weren't real impressed with them.
We took off and went south on HWY
283 out of Altus. As we drove south, we saw
the back edge of the storm, which was quite
impressive. The storm had a nice hail shaft
and great flanking line. We got to HWY 5 and
decided to watch the storm. We knew we
couldn't go east or south, so it was just best to
sit. After waiting about 15 minutes for the
storm to get by us, we started east on HWY 5.
Getting to Tipton, we could see the storm was well
north of HWY 5 and we kept going. When we got
to Manitou, we turned north on HWY 183 and got into
the inflow notch.
The storm looked to have organized
and we were closely watching the lowering. We
also knew there was no way we could make it to HWY
62 before the storm did, so this forced us to
section line roads. Luckily these roads are
gravel improved and we managed to navigate them just
fine. As we got close to HWY 62 the storm's
organization significantly improved and it had a
rapidly rotating wall cloud just off the deck.
This led to some excitement on the amateur radio but
all the reports were good.
The RFD blew out the updraft and
the storm quickly lost the lowering. We
traveled north on HWY 54, knowing that we had some
really bad road choices due to the wildlife preserve
to our east. So, we drove up to HWY 19 and
waited for the storm to get north of us. Once
it did, we headed east on HWY 19 and raced to get
back in the inflow notch. We got on HWY 115
north and noticed some improved organization.
Staying with the storm, we had to turn east on a
section line road to get over to HWY 58. About
halfway through this trip, we saw power flashes
under the updraft area. We called this in and
luckily the TV cameras also had the same thing.
It appears that some wind hit two lines that kept
arching. It was under a lowering and of
concern.
We turned north on HWY 58 towards
Carnegie and noticed the base was rising on the
storm. We weren't that impressed with it any
longer but stayed with it. After some section
line road problems we went east on HWY 9 and north
on HWY 146. By this time the storm didn't look
good at all and we decided enough was enough.
Eventually we saw an updated RADAR and the
developing MCS.
Lessons
Learned -
- The only thing here is my rant against SPC.
Of all the freakin' stupid risk areas to issue. This is the most bogus
risk area I have ever witnessed. Oklahoma has not had a high risk
since May 2004 and we broke the streak with today. I cannot believe a
high risk was issued today. I thought the moderate was good, but even
a stretch. I wasn't interested in chasing today as I just didn't think
it was that great. Sure enough I was right. The storm in
northwest Oklahoma was cool and it produced a tornado. However, that
was it and significance wise nothing else, not even big hail. SPC did
one thing worse, they continued the high risk at 8pm when an MCS was
forming. The most exciting thing was the OKC TV guys proclaiming the
end of the world. This is yet another reminder that the SPC outlooks
are guidance, nothing more. As Andy said, "there is only one April
26th!"
Multimedia
-
Photos near Snyder -
1,
2,
3,
4
Fredrick RADAR
- WMV Format
Enid RADAR - WMV Format
Encounters
-
Engaged
Storm: Tipton
Tornado: No - ohh so close.
Funnel: Yes
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
