Updated 845am CT Tuesday / 21 January 2014
…. A Strong Cold Front with Precipitation Chances Showing Up Thursday ….
…. Sunshine Returns with a Slow Warming Trend for the Weekend ….
On this Tuesday morning…. a cold front is moving south southeastward from northwestern Georgia into southern Mississippi and southeastern Louisiana and into the western Gulf of Mexico to just south of Brownsville and into Mexico. A second.. reinforcing.. cold front is moving southward through the Red River country of northern Texas and southern Oklahoma. High pressure.. behind the fronts.. is centered over southeastern South Dakota. As a result of this surface weather pattern, our surface winds are northerly across our area.
In the upper levels of the atmosphere… a counterclockwise rotating upper level low pressure covers eastern Canada and the eastern two thirds of the USA. Upper level high pressure continues over southern California and the southwestern. An upper level low pressure disturbance is noted west of the Baja Peninsula and southwestern California coast over the Pacific Ocean west of the upper air high pressure area. As a result of this upper air wind pattern, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are northwesterly at 50 to 60 mph.
A dry and stable.. and cooler.. weather pattern continues over the area in the wake of last night’s cold front.
By tomorrow night, another stronger cold front will arrive about the same time that we see the influence of the subtropical jet stream.. and it’s associated mid and high level moisture.. overrun the colder air. As upper air disturbances move overhead and create atmospheric lift, we’ll see a better chance of light precipitation Thursday into Thursday night with much colder temperatures. As precipitation chances decrease and temperatures fall below freezing Thursday night, there is a chance we could see some freezing rain/drizzle and sleet but, at this point, I don’t expect any big problems.
As the upper level disturbances depart the area, a more stable and warmer weather pattern will develop.. with abundant sunshine.. over the upcoming weekend.
Regarding my forecast, my local forecast confidence: My confidence in my forecast is very high through tomorrow.. then falls to medium to high confidence for Wednesday night and Thursday into Friday (some question on precipitation amounts and timing as well as exactly how cold the air mass will ultimately end up being). My forecast confidence rises back to high to very high for Saturday and Sunday.
Have a good Tuesday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel