After the pain in the behind winter weather event last week it was my personal hope our next system would be a bit easier to forecast. Hah! This one is even more difficult because it’s a dreaded cold-core upper-level low. Also known as a bowling ball low, the system itself is quite compact and has very cold temperatures aloft. This type of system does have a tendency to cause dynamically-driven snow in the winter months as it passes overhead a given location. The reasoning is that if precipitation is falling heavy enough – it can ‘drag down’ those very cold temperatures aloft and allow for a wet snow to fall – even with surface temperatures a few degrees above freezing (32F).
Since that dynamic cooling from aloft only happens in close proximity to that upper-low, the track is very important. In addition, sometimes the snow can fall faster than it can melt at the surface – even with temperatures at the surface above the freezing mark. This can cause a wet-slushy snow accumulation and result in a short-duration travel nightmare. Ground temperatures and surface temperatures would remain above freezing, so it would take a heavy snowfall rate to produce accumulations. Even if snow did accumulate it would melt very quickly after the snowfall stopped – so roads would at least be in better shape a few hours after the event.
The forecast for snow will depend heavily on the position of that upper-level low along with the location of a potential heavier band of snow just to the west of it. Confidence is increasing that there will be snowfall across parts of the Big Country, Texoma, and North Texas. This may occur as a wet snow mixing in with rain – or changing over to a wet snow entirely. Again, surface temperatures should remain above freezing and soil temperatures are in the upper 40s. Both factors would limit the threat of accumulations.
There’s a ‘but’ in that though… as stated above, there may be a smaller band of heavy snow somewhere in those aforementioned regions. At this juncture, it looks like that band would be in western North Texas and the eastern Big Country. The eventual position of that heavier band (and if it even develops) will change – and so could that axis. This kind of event (involving those pesky upper-level cold core lows) do have a history of producing surprise impactful winter weather events. Our issue is we simply are unable to pin down the threat of any ‘impactful’ event until we’re within hours of it starting.
The National Weather Service in Fort Worth put this forecast quite well with their afternoon discussion headline.
Confidence that we will see wintry precipitation somewhere across North or Central Texas is increasing. The million dollar question is where, when, and how much?
The forecast is going to change between now and Thursday. Every weather model run will look a bit different. That’s why we are not showing you every model run (produced every six hours). A good forecast is built on consistency and not ‘whip-lashing’ the forecast with changes. Last week’s winter storm out west was a great example of how much a forecast can change inside the 48 hours mark. Perhaps we’re being more cautious because of that, but I’d rather tell you what we know and explain the factors we simply don’t know. Check back several times tomorrow and on Thursday for the latest forecast as this is the kind of system where surprises are probable.
Very windy on Thursday and Thursday Night. Outdoor decorations need to be secured or brought indoors!
Now, how about a forecast aspect that we are pretty confident about? It is going to be windy across all of Texas on Thursday and Thursday Night. This same upper-level low will have a ton of energy with it. We’re anticipating wind gusts of 45 to 60 MPH across the western half of Texas for several hours on Thursday and Thursday Night. Wind gusts of 35 to 45 MPH will become more likely Thursday Night across the eastern half of Texas. Blowing dust is a decent bet across West Texas and the threat of fast-moving grass fires will be near-critical. We’ll chat more about the wind and chance for thunderstorms in East/Southeast Texas in tomorrow morning’s update.