Ticker for April 12, 2011

                CORRECTION! There has been a tornado in Oklahoma this year. I searched the
records diligently but I forgot our most trusted resource this day and age ...
Youtube! There indeed was a tornado on the Oklahoma side of the border on
February 27 near Grainola, OK.

Apparently there were about 14,323 storm chasers observing the twister that day
IN OKLAHOMA. Who wasn't there? A little-known climatologist with an affinity
for quoting 1980s movies. Change the thrust of my Ticker from "there haven't
been any tornadoes yet but you still need to stay prepared" to "there has only
been one tornado thus far but you still need to stay prepared".

Apologies for the error. I've gone from Maverick to Goose in a matter of hours.
Better a correction than an ejection seat.

Thanks to those that spotted my error.

Gary McManus
Associate State Climatologist
Oklahoma Climatological Survey
(405) 325-2253

MESONET TICKER ... MESONET TICKER ... MESONET TICKER ... MESONET TICKER ...
April 12, 2011     April 12, 2011     April 12, 2011     April 12, 2011


Whither tornadoes?

While we had some bumpy weather this past weekend, most of March and April went
without significant severe weather (extreme fire weather is noted to appease the
wildfire gods). That is an obvious by-product of drought, of course. For a
majority of the state, spring is the primary rainy season, as evidenced by these
maps depicting the median percent of annual precipitation for successive
three-month periods (courtesy of the CPC):





And of course the most/a majority/a lot of that rain falls as a by-product of
convection. Ergo, a lack of rain during spring can also mean a lack of storms.

Stay with me, I'm getting there.

It's tough to get tornadoes when you haven't had many storms. We came close in
Ponca City this weekend but that mesocyclone's destruction came from rear-flank
downdraft winds according to a damage survey conducted by the Norman NWS folks.
The average number of tornadoes for the first three months of the year is a
little more than six. Add April to the mix and the average goes up to about 16
tornadoes.

Month        Average Tornadoes
January             0.3
February            0.8
March               4.1
April              10.4

And while we're not even mid-way through April, with each passing day we move
up the chart for the latest start of the tornado season here in Oklahoma, at
least since the most accurate statistics began in 1950. Barring any tornadoes
today (right, and it might rain today too), 2011 will reach third place on that
list.

Top-10 latest first-tornadoes since 1950 in Oklahoma:

Year        First Tornado        Final Count for Year
1962           April 26                   67
1970           April 18                   50
2011           April 12 (and counting)    ??
1972           April 12                   30
2002           April 11                   18
2001           April 10                   61
1952           April 8                    22
1969           April 4                    31
1964           April 3                    53
1968           April 2                    55
1978           April 1                    21

What can we gather from this? Well, that there haven't been any tornadoes yet
this year!

I would try and say it generally leads to a low count, and statistically
I can back that up with an average final tally of 41 tornadoes during these
late starting years. I think that's dangerous, however. Not Iceman-to-Maverick
"Top Gun" dangerous, but the same sort of assumption that could have been made
with last year's slow start. Three tornadoes touched down in Oklahoma from
January 1-May 9 and yet 2010 ended up with the third-highest annual total
since 1950 at 102 (#1, 1999 with 145; #2, 1957 with 107).

In other words, beware the extreme event, regardless of the ambient conditions.
Need I remind you of the 27-inch snowfall back in February midst one of the
state's worst winter droughts in history? We're one May 10, 2010, away from
upping our tornado count to 55.

By the way, you can be my wingman anytime! I was going to go with "I feel the
need ... the need for rain!!" but come on, that would just be corny.

Gary McManus
Associate State Climatologist
Oklahoma Climatological Survey
(405) 325-2253
gmcmanus@mesonet.org