Ticker for April 14, 2004

                
MESONET TICKER ... MESONET TICKER ... MESONET TICKER ... MESONET TICKER ...
April 14, 2004     April 14, 2004     April 14, 2004     April 14, 2004



Frosty Morning for Some in Oklahoma

This morning brought freezing temperatures to several locations in the
Sooner State:


The area of coldest lows shifted south and east compared to yesterday.
The airmass has also modified a bit, and the lows weren't nearly as low.

One very interesting feature in the above hi/lo map is the profound
difference between morning lows at Chickasha and nearby Acme. This
is illustrative of the vast influence of local topography in clear, calm
and stable overnight settings.  Chickasha, nestled in the Washita Valley,
fell to 28 degrees. Two major factors combined to coax temperatures to
that value: its low elevation (relative to surrounding environs), and its
protection (again, relatively speaking) from wind:



Acme, on the other hand, is situated on relatively higher terrain, and
experienced overnight winds of about 5 mph all night. This was enough
to mix the cooling surface layer with slightly warmer air just above the
surface, and avoid the rapid in-situ cooling observed at Chickasha.



Those who have seen the Washita Valley and experienced 5 mph wind
may be surprised that these seemingly modest features can make such
a big difference, but they do!