Updated 845am CDT Wednesday / 27 March 2013
Surface High Pressure Now Well East of the Area ….
Southerly Surface Winds Mean Increased Moisture and Cloud Cover ….
Rain Chances Late Week Through the Weekend and Again Monday into Tuesday ….
On this Wednesday… surface high pressure extends southward from eastern Missouri into Mississippi and southeastern Louisiana. Low pressure is developing over southeastern Colorado with a trough.. or line.. of low pressure southward into eastern New Mexico and west Texas. Given this surface pressure pattern, surface winds are southerly across our area of Texas.
In the upper levels of the atmosphere, upper air low pressure areas are located over the northeastern USA as well as along the Pacific coast of Washington with an otherwise more zonal (west to east) upper level wind pattern. As a result of this upper air wind flow, our upper level winds are light to moderate west northwesterly with winds over Austin at about 18,500 feet blowing about 35 to 45 mph.
With the surface high pressure now east of the area… southerly wind and the associated surface moisture are already increasing. Clouds will make their first appearance tonight into Thursday with the atmosphere becoming more moist and unstable by Thursday night and continuing through the weekend into early next week. We’ll see a slight chance of rain by Thursday through the weekend with the best chance being late Friday night into Saturday as upper air low pressure disturbances move overhead.
Through Monday, as the humidity, clouds and temperatures increase, I do not see any air mass changes. Latest guidance suggests that a moderate cold frontal passage will take place next Tuesday morning in the mid and late morning hours with widely scattered to scattered rain showers and thunderstorms. Slightly cooler temperatures will prevail in the wake of the front for the middle part of next week.
Have a good Wednesday night and Thursday…
Meteorologist Troy Kimmel