Updated 1254pm Monday / 20 February 2012
…. A Quiet Week Ahead Weather Wise for Austin and South Central Texas ….
…. Series of Dry Cold Fronts Through the Area over the Next Four or Five Days ….
…. Above Average Temps First Half of Week; Cooler Temps Second Half ….
On this Monday… a high pressure area extends southward from the Great Lakes and the Ohio Valley region into the southern Mississippi Valley. A developing area of surface low pressure is over northwestern Kansas with a warm front extending southeastward into central Arkansas. A cold front extends south southwestward from the surface low into the Texas panhandle and southeastern New Mexico and far west Texas. As a result of this surface pressure pattern, a southerly surface wind is blowing across our area.
In the upper levels of the atmosphere… a broad trough.. or line.. of upper air low pressure is located over the western two thirds of the USA. Within this counterclockwise rotation, a strong low pressure disturbance is centered over eastern Colorado southward into west Texas and eastern New Mexico. Another low pressure disturbance is diving southeastward from western Nevada and central California. As a result of this pressure pattern, the upper air winds are moderate to strong west southwesterly across Texas and our local area.
As the low pressure.. over northwestern Kansas.. continues to deepen and move eastward, a southerly surface wind continues over the area with clouds a sign of the low level moisture return. By later tonight and into the predawn hours Tuesday, the cold front will move southeastward through our area. Low level moisture and instability will be limited, though, so we’ll see a wind shift to the northwest and that’s about it as the front passes.
Given the progressive (fast moving) weather pattern, the surface high pressure area, following the front, will move eastward quickly with a return southeasterly wind flow by late in the afternoon tomorrow.
Southerly surface wind flow will continue tomorrow night into Wednesday and Wednesday night and into Thursday morning before a stronger cold front moves through the area during the afternoon hours Thursday. Moisture return and instability in advance of this front again looks limited, again, due to the progressive nature of our weather pattern. I’ll include a slim chance of rain showers and thunderstorms in the forecast as the front passes.
Cooler.. drier and more stable air will build into the area Thursday night into Friday as surface high pressure from the Rockies and the plains states moves our way.
As the surface high moves eastward, surface winds will return southerly by late Saturday into Sunday and Monday with clouds on the increase once again.
My forecast confidence through this week is high to very high with the timing of the cold front on Thursday and any associated rain chances being the main questions. My confidence for the forecast for late week through next weekend is high to very high.
For Austin and south central Texas… tonight will be partly cloudy with patchy fog developing late. Lows in the 40s with a southwesterly wind becoming northwesterly 5 to 10 mph as a cold front passes after midnight. For tomorrow, mostly sunny and less humid. Highs in the 70s with a northeasterly wind becoming southeasterly by late in the afternoon.
Have a good Monday night and Tuesday…
Meteorologist Troy Kimmel