Ticker for September 5, 2008

                
MESONET TICKER ... MESONET TICKER ... MESONET TICKER ... MESONET TICKER ...
September 5, 2008  September 5, 2008  September 5, 2008  September 5, 2008



Say Anything about Our Belfry, And We're Socking You

Another great radar event last night; this time right in our backyard.
Let's jump right into the radar reflectivity from the NWS radar near
Frederick, OK:

7:52p: 


This image is just sets the scene ... sunset, western Oklahoma,
not much going on (nice "sunset spike" to the west, though).

8:31p: 


About a half-hour later, some interesting artifacts appear to the
east of the radar. Looks kinda like precipitation. There's also
a little ring-shaped feature northwest of the radar, near Reed.

9:00p: 


Fast-forward another half-hour and the ring shape has expanded.
That's weird. What's going on over there?

To answer what's going on to the northwest, we need to figure out
what's going on to the east, where radar echoes have intensified.
In fact, some of them have reached very healthy 35+ dBZ values.
These are usually associated with pretty heavy rain.

But here's the deal. It wasn't raining, at all. Not even close.
So what was the radar observing?

Well, it's observing the ground, if you want to get technical.
Through a process called "anomalous propagation", or "AP", the
beam was bent into the ground, bounced off, and traveled back
to the radar. AP occurs when there's a strong inversion, or a
shallow layer of cool (thus, dense) air near the surface, that
"refracts" the beam into ground, thusly:



Anyway, AP was responsible for the phantom returns to the east.
But what caused the ever-expanding ring to the west?

9:15p 

9:30p 


Well, AP helped us see this feature, too, which was fairly close
to the ground, but it's obviously not the ground. So what is it?

Bats!

That point near Reed is a cave known to Bat-ologists, Bat-o-philes
and other generally batty people as home to a large colony of
freetail bats. The expanding ring is evidence of large numbers
of bats leaving the colony to do their nighttime thing.

A bat-ologists ("chiropterologist", Latin for "I can't believe
you actually touched that thing.") will claim that the bats are
feeding on insects and doing the world a favor. We'll take their
word for it, but we're still gonna have bad dreams.

Anyway, if you wanna see a movie (about 2MB), it's really neat:

https://content.mesonet.org/ticker/archive/20080905/batmovie.mov

And, if you want to see inbound bats in green, and outbound bats
in red, go right ahead.



A couple notes: the "bat velocity" is really the average of many
creatures. You might say it's a "batting average".

Oh, come on. It was funny.