Updated 845am CDT Thursday / 12 September 2013

…. Very Slim Thunderstorm Chances Linger Through This Afternoon and Evening ….
…. An Otherwise Typical Late Summer Weather Pattern Continues ….
…. Continuing to Watch Disturbed Tropical Weather over the Yucatan Peninsula ….

On this Thursday morning…. surface high pressure continues over the southeastern USA with another high pressure area is to our distant west northwest over the Great Salt Lake basin. A trough.. or line.. low pressure area extends southwestward from western Oklahoma into far west Texas. A southward moving cold front extends west southwestward from southern Missouri into northwest Oklahoma and the northern Texas panhandle. As a result of this surface weather pattern, surface winds are  southeasterly over our area.

In the upper levels of the atmosphere… a strong upper level high pressure area has continued to settle southwestward into the southern plains states. However, an upper level low pressure area is moving southward along the Texas coast. Being on the south side of the upper air high and with the upper level low to our southwest, winds over south central Texas and the Austin metro area about 18,000 feet above the ground are northeasterly 10 to 20 mph.

Atmospheric moisture will continue today to combine with daytime heating and atmospheric instability as well as the upper level low to our southeast to produce isolated rain shower and thunderstorm development. Frequent cloud to ground lightning and gusty winds may accompany the thunderstorms that do develop.

By tomorrow into the weekend, I expect that the upper level high pressure area will build back into our area with increased sunshine and rain chances dropping from the forecast. Temperatures will continue to be at or above average.

By Sunday into next week, a slightly more unstable air mass will move northwestward into Texas from the Gulf of Mexico and I will introduce a very slim rain chance beginning Sunday. These local rain chances will be tied to the development and future movement of the developing tropical system over the Yucatan Peninsula. According to meteorologists at the NWS/National Hurricane Center, there is a fairly high chance that a tropical cyclone (the next name on the list.. Ingrid) will develop over the southwestern Gulf of Mexico by later today and Friday and into the weekend. It continues to be strongly felt that the system will be steered more westward toward Mexico than northwestward toward Texas and, as a result, I am going to keep rain chances very slim for Sunday into early next week. If the current trend continues, I may ultimately drop rain chances all together for the time period.

Regarding my forecast, my local forecast confidence: High to very high forecast confidence through Saturday.. then a medium confidence Sunday into next week with the developing tropical cyclone – its future movement and intensity – over the Gulf still throwing some uncertainty into my forecast (although not as much uncertainty as yesterday, though).

Have a good Thursday…
Meteorologist Troy Kimmel

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