#1902 Postby TheProfessor » Mon Dec 31, 2018 12:40 am
I've been pretty mum with this storm, but right now this does look like a classic overrunning ice event(if the surface is cold enough). You have a trough closing off moving west to east, but before some of the colder dynamics arrive you have over running due to warm air advection over a cold layer. Next thing you know you have freezing rain and sleet. The 0z Nam is definitely concerning with the ice totals. Here's the biggest difference I see between the 18z Nam and the 0z Nam. When I was at the NWS today we were kind of talking about how the mid levels are very dry on the 18z NAM, which would stunt ice growth. Now if you look at the 0z NAM it's much more saturated. Now right now this won't make a huge difference because the skew-t is a classic one for freezing rain. However, if the NAM is too warm and the skew-t becomes more favorable for snow, then you will need those ice crystals to grow and become snowflakes.
Another thing I'm noticing is that both the Icon and the NAM have closed bowling ball lows that move through North Texas or southern Oklahoma. Both models produce snow on the northern side of this upper low. It will be interesting to see where this low ends up being placed. I guess the ultimate dream for North Texas would be for this low to dig a bit more go neutral tilt throwing WAA over a cold dome where the event starts off as sleet, then as the low moves over a band of snow develops and drops a couple of inches over ice. Probably won't happen, but would be a cool, similar repeat to what happened during the Superbowl storm precip wise.
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