April 24, 2006
Storm Chase
Central Oklahoma
Editor: Putnam E. Reiter
Forecast/Setup -
Risk Area: Moderate Risk
Initial Target Area: Kingfisher
April has been very disappointing severe
weather wise with little to no activity in Oklahoma. While a few decent
setups have occurred, not many have been good for chasing. This one looked
like one of the better setups and SPC's moderate risk seemed to confirm this
theory.
The northern stream was dominated by a
ridge in western Canada with a trof to the east. In the lower 48 a southern
stream system was approaching the region on this day. The cold hadn't been
touch in a few weeks and great moisture was available. Models did not
handle the upper system very well as the southern jet stream was quite
active and there was an upstream kicker just off the California coast.
Wind field were progged to be quite
favorable for supercells with good directional shear and decent speed
shear. Since the upper system was a little weak the surface reflection
wasn't that strong, this reduced the overall speed shear. Given that deep
layer moisture returned ahead of this system, this could be enough to
compensate for the lack luster surface flow.
A big complication was overnight
convection that formed in Kansas and moved along the Oklahoma/Kansas
border. This was a severe MCS and continued late into the day. This
produced a strong outflow boundary that moved south and west into the threat
area. The location of this boundary is evident on the instability maps.
The surface low was located over northern Oklahoma with a dryline extending
south-southwest from it to southwest Oklahoma into Texas. A complication
for the event was having storm develop before the dryline met up with the
outflow boundary and/or the synoptic cold front rammed into the dryline.
All the features are notable on the graphics below.
The cap was expected to be strong, per
usual on a chase day. However, it was expected to weaken with the approach
of the weak southern wave and allow for discrete storms. Storms did develop
around 5:30pm across southwest Oklahoma, with severe thunderstorms rapidly
developing. A few storms clustered together in southwest Oklahoma and
almost lined out. However, as they progressed into southern Grady County
the storms became more discrete and one HP supercell continued eastward.
Farther south, another supercell was located along the Texas/Oklahoma border
and produced a tornado. Just to the north in Canadian County a supercell
rapidly developed and produced a tornado over El Reno's airport. This
tornado was caught live by the three major OKC TV media stations. This
storm produced two tornadoes, one of them anti-cyclonic. Storms continued
late into the evening across the region, but there were no more tornadoes.
SPC Products: SWO
Day 1
Graphics:
Risk Area
-
Tornado
Prob -
Damaging Wind Prob -
Hail Prob -
Storm Plot
- LSRs
Surface Maps:
Temperature
- Dewpoint
-
Wind Speed
- CAPE
- LI
-
Moisture Convergence
Sounding:
OUN - 00z
Text Products:
Mesoscale
Discussions -
Watch Products
- Area Weather Updates
-
Tornado Warnings
Mesoeta 00z Initialization:
Surface Pressure
-
0-3km Helicity
-
850mb
Temperatures -
850mb Dewpoints
-
850mb Windspeed
-
850mb Vertical
Velocity -
850mb Relative Humidity
-
700mb Wind
-
700mb
Temperatures
-
700mb Relative Humidity
-
700mb Vertical
Velocity -
500mb Vertical Velocity
-
500mb Temperature
-
500mb Vorticity
-
500mb Wind
-
500mb Relative
Humidity -
250mb Wind
-
250mb Relative
Humidity
The Chase -
Team 1 - Rob Ferguson and Putnam Reiter
Miles Driven - 270
Departure Time - 15:30 CDT
Return Time - 21:55 CDT
We left Oklahoma City had headed north on
HWY 74 to HWY 33 west. Reaching Kingfisher we drove south a little on HWY
81 and watched the clouds. There wasn't much vertical development, but we
stayed for a while. Seeing better development to our southwest we dropped
south to Okarche where we waited some more. Conditions didn't appear to be
much better but it was still early. We were concerned about the outflow
boundary to our east and the distance from the dryline to our west.
About 5:30pm we got word that a storm had
developed near Hobart, so we took off for that part of the world. Time of
day and cold front position were the main reasons for leaving our initial
area. We took HWY 81 south to HWY 152 and went west. We hoped to round the
backside of the storm as it passed over Anadarko. However, the storm rooted
in the boundary layer and slowed down to 15 mph. Anyway, we turned south on
HWY 8 towards Anadarko. Unfortunately the storm was going real slow at this
point, about 15mph. We had to sit miles north of Anadarko and received
nickel sized hail. The storm finally got east and we drove on into
Anadarko. We measured several hail stones, typical 1-2 inches. We went
west out of Anadarko on HWY 9 a few miles. Hearing about the storm in
Canadian County, we turned around and started back up HWY 8.
We got just north of Anadarko when the
tornado warning went out for Canadian County. We went back north to HWY 152
and east, as fast as we could. We got back to HWY 81 and went north to
where HWY 152 goes east out of Union City. We started to get close to the
storm, but the time was near 8pm and daylight was fading fast. As we got
close to the storm we could see a lowering with it, but nothing that
screamed tornado.
We ended up on SW 29th street and watched
the storm until daylight was gone. Since we had the time, we followed the
storm into Oklahoma City. As we got east a little bit we saw some power
flashes just to our northeast. Since it was brief we didn't worry about
it. Heading north on Kilpatrick we saw more power flashes near NW 39th
street. We took a quick exit to see if we could find where they came from.
Driving east we didn't find anything, so we headed on home. Looking at the
OG&E power map there was an outage just east of the location, so what we saw
was correct.
Lessons Learned -
Nothing for this area again. While we did
miss the El Reno tornadoes, we followed what we thought was best forecasting
wise. Many of the people that caught the El Reno storm either saw it
developing from OKC and drove a few miles to it or were with TV stations.
Since we do our own thing, it is easy to end up in the wrong spot.
Multimedia -
None
Encounters -
Engaged Storm: Anadarko, Oklahoma
Tornado: No
Funnel: No
Hail (larger than 0.75 inches): Measured lots of nickel size and a few
2.00 inch stones.
Wall Cloud: No
Wind (above 57.4 mph): No
Engaged Storm: South of El Reno
Tornado: We didn't see it, but it put down two.
Funnel: No
Hail (larger than 0.75 inches): No
Wall Cloud: Yes
Wind (above 57.4 mph): No
