Updated 800am CT – Friday / 26 September 2014
…. A Typical Early Fall Weather Pattern Continues ….
…. More Clouds and Instability with Slim Rain Chances Over Next Day or So ….
On this Friday morning…. a surface high pressure area extends southwestward from the northeastern USA into the Ohio Valley region then southwestward into Texas. An old frontal boundary is stretched out from Florida westward through the Gulf of Mexico to off the Texas coast. As a result of this surface weather pattern, our local surface winds are north northeasterly.
In the upper levels of the atmosphere… a trough.. or line.. of upper level low pressure is over the eastern Great Lakes southward into the eastern USA. There is another trough of low pressure just offshore of the west coast. There is another weak upper level low over west Texas. Upper level high pressure.. acting like a lid on the atmosphere.. has become forced more southwestward into central and western 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 southerly less than 20 mph.
We continue to see more mid and upper level clouds along a slightly more unstable air mass across our area of Texas. Even though it’s a generally dry and stable early fall weather pattern, I will go with guidance that suggests that we’ll see slim rain shower and thunderstorm chances through tomorrow as gulf moisture is returning into the southeastern half of the state as the frontal system in the northwest Gulf of Mexico weakens and washes out.
Once we get past tomorrow night into Saturday, it appears that the atmosphere will become more stable once again with clouds decreasing a little and rain chances dropping from the forecast locally.
Temperatures over the next day or so will be around or perhaps just below seasonal averages.. with those temperatures edging upward to slightly above seasonal averages by Sunday and into next week.
Even though the effects are beyond the seven day forecast period, the latest long range computer guidance continues to show that an upper level trough.. or line.. of low pressure will move eastward through the western USA and into the plains and Mississippi Valley by next weekend with a fairly strong associated cold front likely to move into Texas. Guidance suggest the possibility of rain and thunderstorms with this weather system and cooler temperatures following the frontal passage.
Regarding my forecast, my local forecast confidence: My forecast confidence through tonight is high (considering any precipitation that does develop along with the timing) with my confidence rising back to high to very high for Saturday into Sunday through most of next week in advance of that next cold front next weekend.
Have a good Friday….
Meteorologist Troy Kimmel