Wintry precipitation chances will return to parts of Texas this week. It is currently warm in much of Texas, with some areas close to 90, but the weather will chance drastically overnight into Tuesday.
At this hour, a chilly Canadian airmass is advancing southward into Oklahoma and the Texas Panhandle. This cold front will move through all of Oklahoma and Texas by the end of the day on Tuesday; followed by a reinforcing shot of cold/dry air moving in Wednesday night. This Canadian airmass is what is setting the stage for a cold enough temperature profile to support wintry precipitation. The only ingredient missing is a lifting mechanism to generate precipitation–this will change by Wednesday. A robust upper-level shortwave will traverse (from west to east) across Texas Wednesday into Thursday. The robust nature of this shortwave will act as the lifting mechanism to generate precipitation across parts of Texas.
GFS 500mb Vorticity Map (Wednesday Morning)
A band of precipitation will initially develop in western Texas Tuesday night, and as the shortwave gets closer, the band will evolve into a large band of precipitation across much of the I-20 corridor in Texas. Throughout the day on Wednesday, this band will shift southward into central and southern Texas. This was a trend I noticed in the guidance (the northward trend in precipitation) that I mentioned in yesterday’s article. The northward trend continued today, thus, the introduction of wintry precipitation chances now extending into north Texas (the best chances along and south of I-20).
Forecast atmospheric soundings show a profile that would support wintry precipitation. Initially, the precipitation would begin as a rain then rain/sleet mixture in northern Texas. The same is likely for central parts of Texas. Surface temperatures will be borderline (upper 30s), but wetbulbing will drop temperatures to allow for this wintry precipitation transition. Further southwest, in the Rio Grande, Edwards Plateau, and parts of the Texas hill country, a rain/snow mixture looks to be the primary precipitation type due to a colder atmospheric profile.
GFS Forecast Sounding: North Texas (Wednesday Morning)
GFS Forecast Sounding: Texas Hill Country (Wednesday Night)
Where is snow most likely and accumulations
At this time, the best chance for snow will remain in west Texas, the Rio Grande, the Texas hill-country, and the Edwards Plateau.
NAM Future Radar (Wednesday Morning)
NAM Future Radar (Wednesday Night)
Accumulations do look possible. It is extremely difficult to forecast accumulations this far in advance, in the south, especially when precipitation types may be a mixture; but, light accumulations will likely occur in west Texas and the Texas hill country. A slushy inch may accumulate on elevated surfaces with 1-2″ in the higher terrain. The rain/sleet mixture in north Texas and central Texas should not cause any travel issues but will be fun to watch fall from the sky.