29 November 2015
What A Cold Front!
Posted by Dan Satterfield
A rather incredible surface temperature chart greeted meteorologists this afternoon. An extremely sharp frontal boundary separated very warm weather from unusually cold. Behind the front, temperatures were 10-20 degrees below average, and ahead of it 10-15 degrees above average, and in some spots the departure from normal was even greater. Look at the temperatures at 1 PM EST and you can see that towns in western MS were reporting temps. in the low 70’s while an hours drive away the temp. was in the 40’s.
In Oklahoma, a crippling ice storm is causing widespread power outages. The morning weather balloon sounding (from the NWS in Norman,OK) is indeed a classic sounding for ice (see below). Notice the layer of cold air near the ground, while at 850 millibars (about 5,000 feet above the surface) the temperature was a mild 10º C or 50ºF! Rain was falling into a shallow cold air layer, that was only around 3km thick.
The ground was above freezing, so the roads had no ice, but the trees still have leaves on them, and that always makes things much worse in an ice event. The ice coated branches fell on ice coated power lines and off went the power. In many cases, whole trees fell, blocking roads, and toppling power cables. My daughter in OKC, had no power for much of the day.
Think how much nicer our town and cities would look with all the power lines buried. No ugly cables and trees along the streets…
Alas I tilt at windmills…
(which will change everything in coming years)
We used to call these “blue northers” in Texas. When strong enough they would travel across the Gulf of Mexico and hit the Florida Keys and beyond.