Updated 845am CDT Friday / 27 September 2013
…. Changes Ahead ….
…. A Cold Front Approaches Late Tomorrow into Sunday with a Chance of Rain ….
On this Friday morning…. a high pressure area is over the east and northeastern USA. A low pressure area is over eastern Colorado with a trough.. or line.. of low pressure extending south southwestward through eastern New Mexico. An east southeastward moving cold front extends south southwestward from Nebraska into Colorado and New Mexico and southeastern Arizona. As a result of this surface weather pattern, surface winds are south southeasterly over our area.
In the upper levels of the atmosphere… a deep trough.. or line.. of upper level low pressure is moving slowly eastward out of the western USA and into the Rockies. An upper level high extends from southeast Texas and southwestern Louisiana into the northwestern Gulf of Mexico. As a result, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are southerly 15 to 25 mph.
With surface high pressure now well to the east, a south southeasterly surface wind has become reestablished over the area with an increase in low level moisture as evidenced by the quick return to early morning low cloudiness.
By late tomorrow into Sunday, the strong upper level low over the intermountain west and the northern Rockies will move eastward and, as a result, the southeastward moving cold front out west will move into Texas with scattered rain showers and thunderstorms expected across the area. Forecast rainfall amounts have remained rather consistent with the latest guidance suggesting between 1 to 1 1/2 inches of rain locally between 7am Saturday and 7am Monday.
Once the front passes through and weakens by early afternoon Sunday, rain chances and clouds will slowly decrease Sunday night into early Monday with a little more sunshine and slightly cooler temperatures early next week.
The tropics are relatively quiet with no tropical cyclone development expected over the Atlantic basin over the next 24 hours.
Regarding my forecast, my local forecast confidence: High to very high forecast confidence through the next seven day forecast period.
Have a good Friday…
Meteorologist Troy Kimmel