We’re down to the eve of New Year’s Eve and on the verge of entering 2019. It looks like we may only make it to the second day of January without winter mischief in Texas. This isn’t going to be one of my excessively long and detailed blog posts. Mother Nature has proven many times over the last two months why forecasting winter weather in Texas is difficult. I won’t go into that tirade again either, but let’s list a few items that could make or break winter weather lovers hearts on Wednesday.
- The track of an upper low will be paramount in determining who gets precipitation from Tuesday night through Thursday evening. If the low moves a bit north the precipitation shield could end up 50-100 miles north. If the low moves a bit south we’d likewise see a significant southward shift in precipitation. Minuscule changes in the low’s track will have massive implications in the eventual forecast. This upper-level storm system is moving into the upper-air weather balloon network tonight, so we should start getting a better idea of this forecast aspect by tomorrow morning’s weather model runs.
- Where will the freeze line be located? A strong arctic cold front will arrive tomorrow into Tuesday (north to south) and bring a pretty cold air mass with it. If the airmass ends up being more difficult to erode that would result in the freezing line being more south and east. On the opposite side of the spectrum, if the cold airmass moderates more quickly, the freezing line would be farther to the north. The track of the upper low will play a role and the eventual ‘airmass’ will dictate which precipitation type a given location experiences. It’s possible we may have rain, freezing rain, sleet, and snow (or a mix of it all) set up on Wednesday.
- How much precipitation (regardless of its type) will fall? We’re seeing a fairly high spread among weather models. Some are fairly dry (under a one-quarter inch of rain or liquid-equivalent of rain) while others are upwards of three-quarters of an inch of rain (or liquid-equivalent).
Try and put that all together three days out and you’re just asking for another nightmare forecast. I won’t sugar coat the high probability that significant forecast changes may occur in the coming days. This may end up being a rain event with some minor elevated icing in the Hill Country, Big Country, and Texoma – all the way up to a full-fledged winter weather event with accumulating snow and ice across a larger region. Until we get a better grasp on the track of the upper low, how much moisture will be available, and the temperature profiles we simply can’t say for sure which solution will verify. For now, we’ll take the middle road (similar to that of the National Weather Service and most meteorologists). Don’t freak out and go buy out the grocery store at this point, but be sure to check back for the latest forecast in the coming days. Take this as a ‘heads up’ versus a ‘take action’.