Updated 800am CT – Wednesday / 10 September 2014
…. A Stable Late Summer Weather Pattern Continues with Above Average Temperatures ….
…. Stronger Cold Front with Rain/Thunderstorm Chances Late Friday into Early Saturday ….
On this Wednesday morning…. a high pressure area is to our east southeast over Gulf of Mexico while a trough.. or line.. of low pressure extends southward from eastern Kansas into Oklahoma and far southwest Texas. A southeastward moving cold front extends from near Kansas City into western Oklahoma to near Amarillo then northwestward into Colorado. As a result of this surface weather pattern, our local surface winds are south southeasterly.
In the upper levels of the atmosphere… a deepening trough.. or line.. of upper level low pressure is moving east southeastward through the central and northern Rockies into the plains states. Upper level high pressure.. acting like a lid on the atmosphere.. covers the southern USA from the southeastern USA westward across Texas and into the southwestern USA and northern Mexico. As a result of this pattern, the upper level winds over south central Texas and the Austin metro area, about 18,000 feet above the ground, are variable generally less than 15 mph.
The upper level high pressure area above us is continuing to strengthen a bit resulting in increased atmospheric stability with abundant sunshine as well as warmer afternoon high temperatures as well. However, by tonight into Thursday, as the upper level trough over the northern USA moves eastward, the upper level high pressure area will weaken as upper level winds increase a bit from the west.
As this occurs, it sets the stage for the cold front to the northwest.. the strongest so far of the late summer/early fall season.. to move south southeastward through our area in a couple of surges and off the Texas coast into far south Texas by late Friday night into Saturday. Increased cloud cover and scattered rain showers and thunderstorms will occur ahead of.. along and even behind the front as it moves across our area. Drier and slightly cooler high pressure.. behind the front.. will settle into Texas for late Friday night and the weekend and into Monday as the front becomes stationary over the northern Gulf of Mexico and far south Texas.
Regarding my forecast, my local forecast confidence: My forecast confidence is very high through tonight into early tomorrow. By Thursday afternoon into Friday and Friday night, my confidence goes back to medium to high (concerned with exact rain chances and timing as well as timing of the passage of the cold frontal boundary). My confidence rises back to very high by late Saturday through Sunday and into early next week.
Have a good Wednesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel