Updated  930am Thursday / 8 March 2012

…. Clouds and Rain Continue As Upper Level Low Pressure Moves in from West ….
…. Storm Rain Totals of 2 to 4 Inches Between Now and Sunday ….
…. Much Cooler Temperatures to Prevail Over the Next Few Days ….

On this Thursday… surface high pressure is situated off the east coast of the USA with a deepening trough.. or line.. of surface low pressure.. and an associated cold front.. extending southward from southern Missouri into Texas and northern Mexico. As a result of this surface pressure pattern, a southerly surface wind is shifting northerly as the cold front passes locally.

In the upper levels of the atmosphere, a deep trough.. or line.. of upper air low pressure is located from the northern Mississippi Valley southwestward into the desert southwest with a slowly eastward moving closed area of low pressure over southern New Mexico. As a result of this pressure pattern, the upper air winds are strong southwesterly across Texas.

A surface cold front is moving southeastward through our area ushering in a much cooler air mass. Rain showers and thunderstorms are ahead of.. along and behind the front as it moves though.

Most importantly, the upper level low continues to lag behind the front with an overrunning rain pattern behind the cold front as it moves through. As a result, rain shower and even thunderstorm chances will be continuing over the next few days with a very chilly and damp weather pattern persisting.

While the threat of severe weather for us looks limited and restricted to areas just ahead of.. along.. and just behind the front, current forecast guidance suggests upwards of 2 to 4 inches (with some isolated heavier totals to our northeast) could fall locally before the cold front finally washes out east of the area and the upper air disturbance finally moves northeast of the area over the weekend. This type of rainfall could cause some localized flooding problems especially in areas east of Austin where rainfall has been a little heavier over the last few months.

A drier and more stable weather pattern will develop by early next week with partial clearing and warmer temperatures into the new week.

My forecast confidence through the remainder of the week and through the weekend is medium to high. My forecast confidence rises to high by early next week.

For Austin and south central Texas… tonight will see a much cooler temperatures with widespread rain showers and thunderstorms… heavy rain at times. Low 40s. Northerly winds will be gusty at times. For  tomorrow, a cloudy sky with numerous rain showers and a few thunderstorms. Unseasonably cool with highs remaining in the 40s. Northerly winds will continue.

Have a good Thursday night and Friday…
Meteorologist Troy Kimmel