Updated 845am CT – Thursday / 12 June 2014
…. Another Upper Air Disturbance/Weak Cold Front Late Today into Tonight ….
…. Rain Shower and Thunderstorm Chances Until About Daybreak Tomorrow ….
…. The Dry and Stable Weather Pattern Returns Late Friday into the Weekend ….
On this Thursday morning…. a south southeastward moving cold front extends southwestward across central Oklahoma into the Texas south plains around Lubbock then west northwestward into central New Mexico. Surface high pressure is located over the lower Mississippi valley. As a result of this surface weather pattern, our local surface winds are southerly.
In the upper levels of the atmosphere… the upper level high pressure area has retreated southwestward into north central Mexico. Around the clockwise rotation of the upper level high to our distant southwest, several upper air low pressure disturbances are in process of rotating southeastward across our local area and areas to the north northeast. As a result of the basic 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 20 to 35 mph.
A southeastward moving cold front… along a line from Kansas City southwestward to Oklahoma City to between Lubbock and Midland then westward into New Mexico.. will continue to move southeastward today into tonight before pulling up stationary over central Texas. At the same time, the second in a series of upper atmospheric low pressure disturbances will move southeastward through north Texas by later today through tonight. This upper air disturbance will act with the surface front, over central and north Texas, to create abundant atmospheric lift in an atmosphere that is moist and is becoming increasingly unstable with daytime heating.
In the wake of the first upper air atmospheric disturbance that created widespread rain shower and thunderstorm late last night and earlier today in areas primarily to our north.. we’ll see a second round of widely scattered to scattered thunderstorms by later this afternoon through tonight. NWS/Storm Prediction Center meteorologists have posted a “slight” risk of severe thunderstorms.. with the main risks being larger hail in excess of 1″ in diameter and 58 mph or stronger straight line thunderstorm wind gusts.. for areas from south central Texas and the Austin area north and northeastward through north and northeast Texas and into the ArkLaTex region. The thunderstorm risk is highest in the 5pm to 12 midnight time frame this evening and tonight. Rainfall amounts will be 1/2 inch or less so flooding should not be a problem.
The atmosphere will become more stable once again tomorrow and through the weekend into next week with afternoon high temperatures at or just above seasonal averages.
Regarding my forecast, my local forecast confidence: My forecast confidence is medium this afternoon and tonight and through daybreak tomorrow (as it regards thunderstorm, severe thunderstorm and rain chances). My forecast confidence goes back to very high for tomorrow through the weekend and into the first half of next week.
Have a good Thursday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel