Updated 800am CT – Wednesday / 10 December 2014
…. Rain Chances Show Up Several Times in Upcoming Seven Day Forecast ….
On this Wednesday morning…. a weakening “backdoor” cold front (moving in from the northeast) is oriented from the south coast of Louisiana northwestward through central and north central Texas then as a warm front from northwest Texas and the eastern panhandles of Texas and Oklahoma to a low pressure area over southwestern Kansas. A surface high pressure area.. behind this front.. is over southern Wisconsin. Another surface high pressure area is centered over Colorado and western Wyoming. As a result of this surface weather pattern, our local surface winds are very light.
In the upper levels of the atmosphere.. an upper level low pressure area is located from east of Hudson Bay in Canada southeastward through the northeastern USA. Another upper air low pressure disturbance is moving east northeastward from the southeastern New Mexico and southwest Texas. As a result, our upper air winds at about 18,500 feet are southwesterly about 20 mph.
The upper air disturbance.. to our west.. is continuing to weaken and move east northeastward with thickening and lowering clouds with a chance of rain locally in the forecast. Rainfall amounts of 1/4 inch or less.. according to the latest NWS guidance.. are expected through tomorrow with this passage of this weather system.
We’ll see clouds break with some sunshine expected by Friday into Saturday before another stronger upper air disturbance and surface cold front moves into the area by Sunday into Sunday night. This second weather system appears to be a little more dynamic with increased clouds and rain shower and thunderstorm chances returning to the forecast for as early as Saturday night and then peaking Sunday and Sunday night. I expected, based on the current guidance, that the cold front will pass through our local area around midnight Sunday night. Isolated heavier thunderstorms may accompany this system with rainfall guidance suggesting upwards of 1/2 to 3/4 inch with the system.
It appears that a drier and cooler weather pattern will develop in the wake of the Sunday night/Monday morning upper air low pressure storm system and cold front.
Regarding my forecast, my local forecast confidence: My forecast confidence is medium to high today through Thursday night and again late Saturday through Sunday and Sunday night with precipitation chances and timing being the uncertainties.
Have a good Wednesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel