Updated 800am CT – Thursday / 11 September 2014
…. One More Day of Above Average Temperatures ….
…. Stronger Cold Front with Rain/Thunderstorm Chances Tomorrow into Saturday ….
On this Thursday morning…. a cold front is moving slowly southeastward from the Missouri bootheel into the ArkLaTex region to near the Dallas/Fort Worth Metroplex and southwestward to Brady into southwest Texas then northwestward into New Mexico. 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 from the 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. 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 is still above us, however, 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 tomorrow afternoon and night into early 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. Current guidance suggests that we could see up to 1 to 1 1/2 inches of rainfall mainly between now and Saturday night.
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. The latest guidance is keeping more clouds and even some slim rain chances back behind the front into early next week as upper air disturbances.. from the est and northwest.. traverse the area with temperatures slightly below average for this time of year.
Regarding my forecast, my local forecast confidence: My forecast confidence over the next 48 hours is 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 high by late Saturday through Sunday and into early next week (slightly reduced with the uncertainty of any rain chances as well as increased cloud cover).
Have a good Thursday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel