Updated 845am CT – Wednesday / 5 February 2014
…. Much Colder Moving Southward Through Texas ….
…. Overrunning Clouds and Precipitation Event Late Tonight and Thursday into Friday ….
…. A Warming Trend into the Weekend But Colder Late Weekend into the New Week ….
On this Tuesday morning…. an arctic surface high pressure area is building southward into Texas from western Canada and the north central USA. As a result of this surface weather pattern, our surface winds are northerly across our area.
In the upper levels of the atmosphere… the counterclockwise rotating upper level low pressure continues just northeast of Hudson Bay with one upper air trough.. or line of low pressure.. having moved northeastward across our area with another one moving eastward through the southwestern USA. As a result of this upper air wind pattern, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are southwesterly at 60 to 70 mph.
Following the cold frontal passage in the predawn hours this morning, we’re seeing partial clearing.. northerly winds and much colder temperatures.
By tonight into Thursday and Friday, another overrunning pattern will develop as other upper air low pressure disturbances out to our west moves east northeastward across the area. With temperatures forecast to be below freezing late tonight into early tomorrow and again tomorrow night into Friday morning and, at the same time, forecast guidance suggesting the possibility of light precipitation, we must consider the possibility of freezing drizzle or very light freezing rain and some very light icing. The same guidance suggests relatively slim precipitation probabilities.. generally less than 20%.. so I still consider this a “low” probability event but we know if it does materialize, it could have a high impact locally. If you want proof of that, look at our most recent two freezing precipitation events. I’ll continue to monitor this possibility closely.
The overrunning pattern will persist through Friday with clouds and precipitation chances decreasing late Friday into Friday night and Saturday with warmer temperatures. Our next strong cold front arrives midday into early afternoon Saturday. Much cooler temperatures will follow with little in the way of cloud cover for Saturday night into Sunday.
Clouds will increase by Sunday night into Monday and Tuesday of next week as another surface low pressure area and cold front moves through the area early Tuesday morning.
Regarding my forecast, my local forecast confidence: My confidence in my forecast is high today through midnight tonight. My forecast confidence falls to medium to high after midnight tonight through Friday (still concerned with precipitation timing, chances and types). My forecast confidence rises back to high for Friday night through the weekend and into early next week.
Have a good Wednesday…
Meteorologist Troy Kimmel