May 29, 2004
Storm Chase
Western/Central Oklahoma
Editor:
Putnam E. Reiter
Forecast/Setup -
Risk Area: High Risk
Initial Target Area: Woodward, Oklahoma
The Southern Plains had been
somewhat active this week, given the relatively quiet year across Oklahoma.
The models consistently progged a longwave trof to develop across the western
U.S. This trof was progged to be near the central U.S. by Saturday
afternoon. Lack of significant cold fronts meant that Gulf moisture
was in ready supply and of course so was the cap or elevated mix layer (EML).
Supercells developed across parts of Oklahoma Monday and Tuesday as
thermodynamics were quite favorable for severe thunderstorms. Memorial Day
Weekend usually provides interesting weather and this one lived up to the hype;
after a quiet 2003!
Even from several days out this
chase appeared to be prototypical for a severe weather outbreak. While the
very warm temperatures and strong cap were negative factors, many other
parameters were favorable. A weak cold front slipped into the region on
Wednesday and hung around for a few days. As the surface low developed
across Kansas very rich Gulf moisture returned to Kansas and Oklahoma. By
Saturday afternoon CAPE values were near 4000 J/Kg with LIs near -10. Wind
fields at all levels were progged to increase during the day, especially by
mid-afternoon. Strong turning noted from the surface up to 700mb indicated
potential for rotating storms. The cap was progged to increase during the
day and had the potential to prevent storm development. However, the
presence of strong daytime heating and mid/upper jet maxima indicated that the
cap would be breached. Per usual the models were too far east with the
dryline. Said feature barley made it into Oklahoma at convective
initiation. Our forecasting techniques took this into account and helped
us adjust the target area west to near the border. Our pick was Woodward
for this reason.
During the morning hours a
strong shortwave trof ejected out of the mean longwave trof position and moved
eastward across Oklahoma. It was thought that this shortwave trof would
result in convective development, however this did not occur. The
shortwave trof did veer surface winds across much of the state and limited
dryline convergence for a period of time.
By 3:00pm towering cumulus
was developing along the dryline as a mid-level jet max moved across the region.
Additionally, surface winds were beginning to back, increasing dryline
convergence. SPC issued an enhanced tornado watch for much of western
Oklahoma into Kansas. Storms rapidly developed along the dryline in
western Oklahoma. The eventual storm evolution led to two parent supercells in this area. The first one traveled from western Oklahoma near
Custer City (after a cell merger) eastward to near Oklahoma City and on to
Tulsa. Another cell developed north of Woodward and moved into southern
Kansas. This storm moved east-northeast to near Wichita. This storm
was by far the most prolific tornado producer of the day. The Oklahoma
City storm was mainly a hail producer, 4.50 inch hail and a report of 5.00 inch
hail. However, this storm did produce several brief tornadoes, including
an anti-cyclonic tornado.
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
Text Products:
Watches
- Mesoscale Discussions
- Tornado Warnings -
Warning Decision Updates
-
Public Severe Weather Outlook
- Hazardous Weather Outlook
Soundings:
OUN ARPS
Sounding -
OUN -
GAG
Mesoeta 00z Initialization:
Surface Pressure -
Convective Inhibition
-
0-1km Helicity
-
0-3km Helicity
-
850mb Temperatures
-
850mb Dewpoints
-
850mb Windspeed -
850mb Vertical Velocity
-
700mb
Wind -
700mb Temperatures
-
700mb Relative Humidity -
700mb Vertical
Velocity -
500mb Vertical Velocity -
500mb Temperature -
500mb
Vorticity -
500mb
Wind
-
250mb Wind
-
250mb Relative
Humidity
The Chase -
Team 1 - David Underwood, Rob
Ferguson, Andy Wallace, and Putnam Reiter
Team 2 - Allen Wright, Ray Hardy, and Don Clark
Miles Driven - 480
Departure Time - 12:45
Return Time - 21:40
We left Oklahoma City around
12:45, after getting the group together! We headed up Highway 74 from
Edmond to Highway 33 and then west to Kingfisher. We saw a few chasers on
our way out west. Heading on west from Kingfisher we got to Watonga in
good time. Stopping there for a brief break, we took a chance to look
around and talk about the weather setup. We had been monitoring the
weather feed on the way out, mainly CAPE values and such. While in Watonga
we decided to head on to Woodward, our initial chase target. However,
information from Regional Weather Updates cause us to stop in Seiling and talk
some more. After getting fuel, the group headed out just west of Seiling.
The initial plan of going to Woodward was put on hold for fear of committing to
Northwest Oklahoma.
The group sat just west of
Seiling on Highway 60, time was about 15:00. We had RADAR data and
continued watching attempted storm development along the dryline. SPC issued
a tornado watch for the area and from this point it was just a matter of time.
Storms eventually developed along the dryline with several storms noted by the
group to our west. After watching RADAR for about 30 minutes we decided
that the Cheyenne storm looked the best. It had held its own for a while
and would probably survive. At this time no storms had established
themselves near Woodward, although coordination with Jay indicated it was just a
matter of time.
We took off south on Highway
183 through Putnam and turned west on Highway 33 towards Butler. We had a
tough time getting storm scale features as we drove west. Also, a tornado
warning was issued on this storm. Periodic RADAR data continued to
indicate that this storm was surviving. We turned north on Highway 34
towards Leedey. We did get storm scale features here and noted a rain free
base. It briefly had a wall cloud feature but this dissipated. The
base was high, as noted by the rather high LCL's. We wanted to get into
Leedey to get gas and tried to do so. That failed rather miserably, so we
went to Highway 47 and turned east towards Rhea. The storm had some
low-level features but nothing impressive. As we got close to Highway 183
the storm lost much of its low-level features. About this time we also
noted a storm to our south. Figuring that a storm merger would occur or
this one was getting cutoff, we broke off of it. We headed south on
Highway 183. The initial thinking was to head south to Arapaho and fall in
behind the southern storm.
This plan did not work out too
well as the storm merger occurred on top of us. So as we punched
through the northern rain curtain of the approaching storm. Seeing that
this wasn't working well we stop at Highway 183 and Highway 33. Actually
we drove in circles for a few minutes trying to decide what to do. The
smart move was to sit as we noted the back edge quickly approaching. We
did get some golfball sized hail, although not much of it. A little does
go a long ways though. Shortly after that we noted rotation to our
immediate south. Deciding that getting west a little bit was a good idea,
we drove about two miles west of where Highway 183 and Highway 33 meet.
Here we monitored the wall cloud and brief funnels. As the rotation area
moved east we drove in behind it.
We drove east on Highway 33
into Custer City where we encountered 4.50 inch hail. The common hail size
was at least 3.00 inches. I saved several stones and we have two of them
now. We got on east of Custer City on a county road as the storm continued
moving eastward. NWS forecast movement started to indicate an
east-southeast movement. We adjusted for this motion as we got east of
Custer City. As we got to Highway 54 south of Thomas, we went south.
About six miles south of Thomas several power poles had been blown over.
We pulled over a few minutes later to watch the rotation area. Seeing a
well defined wall cloud we watched it for a while. Road options in this
area were pretty bad and we had to re-position. We took Highway 54 south
to Weatherford, where we get fuel. Heading east on I-40 we attempted to
re-engage the storm. We exited north of Hinton on Highway 281 and went
north towards Geary. A few miles south of Geary we turned east on a dirt
road and traveled east towards Calumet. We drove north about a mile and
then back east at this point. As we got east of Calumet we noticed a
funnel developing and stopped to watch it. At this point we got several
brief tornadoes. After watching it for a while we realized that it was an
anti-cyclonic tornado.
Seeing the tornado lift, we
headed on east to stay with the storm. We had to navigate around the
section line roads and ended up near Concho. The storm continued to
produce strong winds during periodic RFD cycles. As we got to Highway 81,
we turned north for about a mile. Lined up along the road were hundreds of
chasers. We turned back east on Memorial Road and followed the storm.
Shortly down the road we got wrapped by the RFD and headed south to Hefner Road.
We turned back east on Hefner Road just southwest of Piedmont. We saw
power flashes as we drove east on Hefner Road. We got to the Kilpatrick
Turnpike where we went north about a mile and then back east. We continued
to see periodic power flashes as we turned east. Dark was quickly
approaching at this point and we decided to sit near Highway 77 for a while.
Getting asked to leave the turnpike, we exited to Highway 77 and headed home.
Lessons Learned -
- Cell merger almost nailed us
but good coordination and some yelling kept us safe. Given that 4.50 hail
fell two miles to our east we did have a little bit of luck on our side.
- My personal complaint was not following through to our chase target.
While we ended up on a good storm, we certainly did not want to play "tail end
Charlie." This may become a rule when dealing with high LCL's (large
temperature/dewpoint spreads).
Multimedia -
- Video (Requires
Microsoft Media Player 9.0 or newer):
Video of
an anti-cyclonic tornado just east of Calumet, Oklahoma, we are looking north.
Clip 1 (14MB). Another
tornado just east of our previous location.
Clip 2
(5MB). Hail/RFD just west of
Custer City.
Clip 3 (4MB).
RADAR Animations:
Oklahoma City
(16MB) -
Tulsa
(7MB) -
Enid
(11MB)
Webcam
(4MB)
- Stills
The crew hanging around before
storms developed:
1,
2,
3,
4
4.50 inch hail stone:
1
Wall Cloud west of Custer City (19:11 CDT) looking southeast:
1,
2,
3
Funnel just east of Calumet (20:55
CDT) looking north:
1,
2,
3,
4,
5,
6,
7,
8,
9
Tornado just east of Calumet
looking north:
1
Encounters -
Engaged Storm: Near
Strong City
Tornado: Yes - anti-cyclonic - east of Calumet
Funnel: Yes
Hail (larger than 0.75 inches): Yes - 4.50 inches
Wall Cloud: Yes
Wind (above 57.4 mph): No
