Precipitation coming to an end, much colder air returns later tonight. Residual moisture on some roads could pose a problem in some areas.
...AREA OF CONCERN...Areas of the NW Hill Country and northern sections of South Central Texas. Llano, Burnet, Williamson, Travis Counties are my biggest area of concern. Much smaller concern elsewhere.
...IMPACTS...Some residual water on roads may freeze later tonight as temperatures drop below freezing. We are not expecting freezing precipitation anywhere (rain or drizzle while temperatures are at or below freezing). Water that is already on the roads from todays drizzle may not dry fast enough in some spots making some ice patches later on tonight. I think the main concerns will be the less traveled roads and the shoulders/sides of the roadways where larger puddles may have developed.
...TIMING...Temperatures are expected to drop below freezing across the extreme northern areas of South Central Texas by 10 pm tonight. This includes sections of Burnet/Llano/Travis/Williamson Counties. So concerns will start to increase by 9-10 pm in these NW sections of South Central Texas if areas drop below freezing and roads are still wet.
...DISCUSSION...This arctic outbreak just keeps on giving. And its not giving easy forecasts. Our issue late tonight into early Tuesday morning will be whether or not the roads will dry fast enough by the time freezing temps come in later tonight. I am not a road expert but several factors typically come into play when you talk about the road surfaces and how fast they dry. For most of South Central Texas, everybody will be fine given the fact the drizzle will end by late evening and for the entire southern half of South Central Texas, the temperatures will be above freezing until well past midnight...giving ample time for evaporation and the roads to dry. But for the northern half of the area, especially Llano, Burnet, Travis, and Williamson Counties, temperatures have been in the 30s all day and forecast to drop into the lower 30s and below freezing by around 10 pm. That only gives a few hours to dry the roads. Winds are forecast to pick up, and drier air is also forecast to come into the region at this same time. Those two items will help dry the roads, am just not sure if they will occur fast enough to keep us out of having some problems on the roads.
Key to this evening and overnight...monitor those roads and monitor the temps. See how fast the roads are drying. Typically in past events like this, the interstates and well traveled roads do fine because of the amount of travel and the driving helps to get the water off the road.
I will be monitoring overnight as well and send out updates if need be. If you see bad road conditions, let the NWS know about it so we can share with the partners through our local storm reports and weather statements.
After tonight...our issues with this arctic airmass should be done....thank goodness.
You can see the latest forecasts and watches/warnings/advisories by going to the Austin-San Antonio National Weather Service website at www.weather.gov/austin