Ticker for December 23, 2008

                
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December 23, 2008  December 23, 2008  December 23, 2008  December 23, 2008



Every Meteogram tells a story

Today's meteogram at Minco shows the distinct trace of a common
winter malady: evaporational cooling



The top panel shows temperature (pink) and dew point (green). You
can see that the constant drizzling of drizzle into the cold, dry
air down here raised the dewpoint temperature. But look at the
hours around sunrise (7 am). The drizzle increased, causing a
pronounced bump in dewpoint. But evaporation is a cooling process,
so the temperature actually dropped during the period.

By 10 am, the wind monitor (33 feet off the ground) was taken out of
commission by the Mesonet's diligent Quality Assurance team. The
wind speed were grinding toward zero, indicating the accumulation
of ice on the sensor, an even more maladious malady than simple
evaporation cooling! A look at the 1 pm map shows a dozen or so
missing wind barbs from central through south-central to southeast
Oklahoma:




The Obligatory "It Could Be Worse" Statement

It's been a cold month. Both Oklahoma City and Tulsa are running an
average temperature of about 37.5 degrees over the first three weeks,
and the month will surely end up at least a couple degrees below the
so-called normal of about 39.5 degrees.

But it's been worse. A quarter-century ago, December 1983 became what
is possibly the most anomalous temperature-month in Oklahoma history
when it bottomed out in the mid-20s (Tulsa had it slightly worse, if
you're keeping score). To put that into perspective, to match the
coldness of 1983, the last nine days of this already-cold month would
need to average THREE DEGREES (that's high and low temps averaged
together). By the way, that's pretty much what happened during the
week before Christmas Day in 1983.