Updated 845am CT Wednesday / 11 December 2013
…. Chilly Temperatures Continue ….
…. Clouds and Rain Chances Increase Again Late Week ….
On this Wednesday morning…. an Arctic surface high pressure area is centered from east Texas northeastward across northern Mississippi and western Tennessee. A trough.. or line.. of low pressure extends southward from eastern Colorado and western Kansas into far southwest Texas. As a result of this surface weather pattern, surface winds are becoming more easterly across our area.
In the upper levels of the atmosphere… an massive upper level low over Hudson Bay and an associated trough, that extends southward through most of the USA, continues slowly eastward. This pattern, with the counterclockwise flow around the low, continues to support the draining of cold arctic air from northwest Canada down into the central USA. Another upper level low pressure area is located southwest off the southern California coast over the Pacific. As a result, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are west southwesterly 45 to 55 mph.
A massive area of arctic high pressure continues to hold over the south central and southeastern USA.
The surface high has moved slowly eastward but the cold air is quite dense and heavy so it will be hard to dislodge.
By late tonight into Thursday, the upper level low.. off the southern California coast.. will move eastward into northwest Mexico and will, once again begin to increase overrunning clouds and rain chances that will continue through Friday. Unlike the last week, though, temperatures will be above freezing with precipitation remaining in liquid form.
Once the upper air disturbance passes by late Friday, we’ll see the clouds break and the precipitation chances drop from the forecast. With the increased sunshine over the weekend and into early next week, we’ll see daytime high temperatures warm but still remain below seasonal averages for this time of year.
Regarding my forecast, my local forecast confidence: Very high forecast confidence through today and tonight. My forecast confidence then drops to high for tomorrow into Friday (reference to precipitation chances). For Saturday into next week, my forecast confidence rises back to high to very high.
Have a good Wednesday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel