Sunday, December 3, 2017 12:05 PM

Update: Texas Snow Looking Likely This Upcoming Week

Christopher Nunley

Confidence is growing that parts of Texas will receive snowfall this upcoming week, so enjoy the warm temperatures while they last.

The setup
A chilly Canadian airmass will settle into the Southern Plains by early to mid-week. The initial cold front will move into Oklahoma and Texas Monday into Tuesday with a reinforcing front moving in Wednesday afternoon/evening. This will set the stage for the thermodynamic profile to be supportive of wintry precipitation. Things get interesting by mid-week when a robust upper-level shortwave traverses (from west to east) across Texas Wednesday night into Thursday, and work in tandem with the upper-level trough axis that will dive southward into the Southern Plains.

GFS 500mb Vorticity Map (Wednesday Night)

This will increase lift and likely generate a band of precipitation from western Texas into the Texas hill-country. Forecast atmospheric soundings show a profile that would support a rain/snow mixture quickly changing to snow. Initially surface temperatures will be borderline for snow (upper 30s), but wetbulbing will drop temperatures to near or below freezing Wednesday night.

GFS Forecast Sounding (Wednesday Night)

Where is snow most likely
Right now, the best chance for snow will remain south of I-20 in west Texas, the Rio Grande, the Texas hill-country, and the Edwards Plateau. Latest guidance is trying to nudge the precipitation closer to I-20, so rain/snow chances may be introduced into locations further north as we get closer to Wednesday.

GFS Future Radar (Wednesday Evening)

Accumulations
Accumulations do look possible. It is extremely difficult to forecast accumulations this far in advance, but light accumulations will likely occur in the aforementioned areas. Right now, it appears a slush inch may accumulate on elevated surfaces with 1-2″ in the higher terrain.

GFS Snow Forecast (Wednesday Evening-Thursday Morning)

Again, the finer details need to be ironed out in this forecast, but I will have updates as needed. Expect an accumulation map from me tomorrow evening, so keep checking back for details.