Ticker for October 28, 2008

                
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October 28, 2008   October 28, 2008   October 28, 2008   October 28, 2008



Frost Bites (Almost) All of Oklahoma

This morning brought sub-freezing temps much of the state, leaving
almost all of Oklahoma in the "Already Froze this Fall" category:



A few interesting things to point out on that map. First, notice that
the coldest temperature achieved (21F, looking at the gray numbers)
occurred down southeast at Antlers in Pushmataha County. Weird.

So, what happened? Did a rogue blob of super-cold air wither and
wend its way from the north, avoiding a maze of Mesonet monitoring masts
to settle in western Push County? No, of course not!

The anomalous cold temperature speaks to the massively local nature of
low temperatures on calm nights. Atoka's temps bottomed out this morning
due to the perfect combination of clear skies and light winds (we'll
call it "The Perfect Calm"):



In other words, a blast of cold air may push the thermometer down, but
the places that get the coldest have more to do with rapidly cooling
the air in place, rather than bringing even colder air.

Another interesting double-feature: The Medicine Park Mesonet station
(southwest) and the Lahoma station (northwest) are the only two to
remain above freezing throughout the episode.

Medicine Park is easy to explain. The station is on high ground (it
sits upon a hill in the Wichita Mountain system). As such, it often
stays "above the fray (-zing temps)" simply because it is higher than
the thin layer of cold air below. It is a well-known "inversion poker"
that often stands out (literally!) from its Mesonet neighbors.
Here's a graphic that illustrates the situation:



(Medicine Park's elevated status is even more dramatic than Cheyenne's)

So, that's one explanation. What about Lahoma?

Well, we're not gonna make any super-confident statements, but we think
it has something to do with the abundant moisture in the area:



The Lahoma site has the highest soil moisture value in the state, and
we think it's no coincidence that temperatures hovered just above
freezing all night last night:



Moisture is nature's great moderator. It keeps maximum temperatures
lower, and minimum temperatures higher. The combination of additional
moisture in the lower atmosphere, plus just enough windiness to keep
things "stirred up" helped delay - at least for a little bit - Lahoma's
inevitable decline into the "Has Frozen" category.


Further Proof that World is Inherently Weird

When winds switch abruptly to southerly, that's supposed to warm you
up, right? Don't tell that to folks in the western panhandle. Thanks
to a switch to southerly winds, they got another taste of the cold air
that plowed through the area the day before: