Updated  130pm Wednesday / 4 Jan 2012

…. A Dry and Stable Weather Pattern Continues ….
…. A Cold Front Slips Through the Area.. Another One Due Saturday ….

On this Wednesday… a dome of surface high pressure area is located over the southeastern USA. A cold front extends from a low pressure area over northern Illinois southwestward into eastern Oklahoma and central Texas. Another high pressure area.. building southeastward behind the front.. is located over Colorado and Utah. As a result of this surface pressure pattern, surface winds are becoming northwesterly as the front moves southeastward across our area.

In the upper levels of the atmosphere… a deep trough.. or line.. of upper level low pressure extends southward from eastern Canada across the eastern half of the USA. Within that trough and its counterclockwise flow, an upper level low pressure disturbance is moving east southeastward across Texas. As a result of this pressure pattern, the upper air winds over Texas continue light to moderate west northwesterly across our area.

Even as the cold front moves southeastward across the area, a dry and more stable surface weather pattern continues over the area with a mostly clear sky. In the wake of the cold front, high pressure will build into the area from the northwest and will act to reinforce the air mass in place with the dry weather pattern will continuing mid and late week into the weekend.

As the high pressure moves east, we’ll see a return to a southerly surface wind flow by late Thursday into Friday with a few more clouds showing up along with increased humidity.

Another cold front.. again, it appears, a dry one.. is expected Saturday with a partly cloudy sky and slightly cooler temperatures for the latter part of the weekend.

Longer range guidance suggests that, in general, the upper level jet stream pattern will shift southward a bit with a stronger upper level low moving across the southern plains states by early into mid parts of next week. While the guidance isn’t in complete agreement and diverges in thought as far as timing and the exact track of the upper level storm system, I still think that an overrunning pattern will likely develop with more clouds and, at least, a slim chance of rain by Sunday night into early next week.

My forecast confidence through the remainder of the week and through the weekend is high to very high (the only question being the timing of the Saturday cold front). My forecast confidence drops to low for early into mid parts of next week as it regards the track and the potential effect of a passing upper level low pressure storm system.

For Austin and south central Texas… tonight will be mostly clear. Lows around 40. Northerly wind 5 to 10 mph. For tomorrow, mostly sunny. Highs will make it into the 60s with a northerly wind becoming northeasterly by late in the day.

Have a good Wednesday night and Thursday…
Troy Kimmel