AREA OF CONCERN...Possible light winter precip accumulations north of a line from Del Rio to San Antonio to Schulenburg. A wintry mix of precip is also possible elsewhere (Rio Grande and Coastal Plains) but we are not looking at accumulations at this time.
IMPACTS...Could see some light icing mainly on bridges and overpasses . Other less traveled roads could also see some light accumulations and icy conditions. The early morning commute on Friday morning may be impacted. Cold temperatures will be in place Thursday and Friday...with highs some 30-40 degrees cooler than what we saw on Monday.
TIMING...Mainly 6pm Thursday to 6 am Friday morning. The area of concern will shift southeast early Friday so areas to the southeast will possibly have effects that last longer through Friday Morning.
DETAILS...Another strong cold arctic front is headed our way and will push into South Central Texas likely during the predawn hours Thursday morning. High temps on Thursday may in fact come during the morning as the cold air moves in during the day with temperatures staying in the 30s and 40s during the afternoon. A weak disturbance is coming out of the Rockies and will move over Texas Thursday night into early Friday. While the chances are not great...forecast models continue to develop some precipitation with this system...albeit...totals are not very high...generally about a tenth of an inch or lower. The problem is that the arctic air will continue building down into the area Thursday night and early Friday dropping temps below freezing...setting the stage for possible winter precipitation starting Thursday afternoon in the Hill Country...and spreading east and southeast Thursday night into early Friday. Temperatures are expected to fall below freezing across all of South Central Texas by around Midnight late Thursday night.
The atmosphere looks to be cold enough to maybe even see some snow mainly across the northern half of the area...north of a line from Del Rio...to San Antonio...to Schulenburg. At this point about 36 hours out...we are calling for some sleet and snow mix. This best chances to see some accumulations are in the Hill Country where we are currently forecasting around 1/4 inch of accumulation of snow. So we are talking maybe a little more than a dusting.
With the ground being so warm because of our near record temps yesterday...I dont think we will see widespread icing problems. I do think the best chances of seeing accumulations will be on grassy surfaces, bridges, overpasses, and less traveled roads. Being that this system is coming out of the Rockies and is fairly dry to begin with, I am fairly confident that the overall amount of precipitation will be light. My confidence is much lower however on whether we may see freezing rain, sleet, or snow. Right now we are pointing toward light sleet and light snow. Temperatures are expected to climb above freezing by Friday afternoon so if this event does occur...it should be be quickly gone by the afternoon.
This is just the first email...more to come Wed and Thu. Watch the forecast closely as things can change rather dramatically based on the latest weather information and forecast models. Responders need to start looking at possible staffing Thurs night into Friday. With the overall chance of precipitation only 30-40%...this is by no means a "slam dunk" sure thing event. Its still way early in this event...and hopefully over the next 24 hours we can fine tune the forecast and get more confident in what we will likely see or not see.
You can get the latest forecasts and watches/warnings/advisories by going to the Austin-San Antonio National Weather Service website at www.weather.gov/austin