Updated 845am CT Thursday / 12 December 2013
…. Chilly Temperatures Continue ….
…. Clouds Pick Up and Rain Chances Increase Tonight into Friday ….
…. Drier Weather.. Sunshine.. Warming Trend for the Weekend into Next Week ….
On this Thursday morning…. a surface high pressure area is centered from north Texas northeastward across Arkansas into the western Ohio Valley region. 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 northeasterly across our area.
In the upper levels of the atmosphere… an upper level low over eastern Canada and the eastern half 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 and eastern USA. Another upper level low pressure area is located along the southern California coast around San Diego. 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.
The large area of modified arctic high pressure continues to hold over the eastern half of the USA. The surface high continues to move slowly eastward but the cold air is quite dense and heavy so it is difficult to dislodge from the southern plains.
By late tonight into Friday, the upper level low.. along the southern California coast.. will move eastward across northern Mexico and southwestern USA and will begin to increase overrunning clouds and rain chances that will begin later tonight and will continue 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 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: My confidence in my forecast is high today.. tonight and Friday (a little question about exact rain chances and timing). For Saturday into next week, my forecast confidence rises back to very high.
Have a good Thursday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel