NWS Austin/San Antonio forecast discussion. Holding with winter weather products (warnings/advisories) and mentions cloud cover potentially helping to moisten columns above which may begin winter weather a little earlier with perhaps a bit more sleet/snow than freezing rain. So at least further east as South Texas Storms also mentioned, the cloud cover arriving faster than models had may offer some clues about the transition to snow into the Houston metro.
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 236 PM CST Mon Jan 20 2025
- Winter Storm Warnings and Winter Weather Advisories are in effect
tonight through Tuesday
- Accumulating snow, sleet, and ice will make travel difficult and
inadvisable within the Winter Storm Warning area
- Cold Weather Advisory in effect through Wednesday morning with
hazardous temperatures and wind chill values. Protect People, Pets,
Plants, and Pipes from the cold weather
Cloud cover has developed much quicker, nearly 6 hours ahead of what
hi res guidance was indicating. This has acted to allow the
atmosphere to respond and moisten perhaps a bit quicker than
previously thought. Very light echoes are noted on regional radar
imagery early this afternoon to the south and east of San Antonio.
For now, this is not hitting the ground and likely remaining virga,
which is precip that evaporates in the sub-cloud layer before
reaching the surface. It is likely that it will take several hours
before any precip starts to make it to the surface. Latest 12Z CAMs
and global guidance, in additional to the NBM have continued to
advertise a very messy winter weather event unfolding this evening
through the overnight hours. One of the more recent trends is for
precip to end a bit sooner, likely out of our area as early as 12-
15Z Tuesday. This has acted to limited totals somewhat, and we will
continue to advertise between 0.5 and 1.5" of snow/sleet for
Austin/San Marcos areas and points east to La Grange. Some freezing
rain could briefly mix in, but primarily snow and sleet is expected
in these areas.
Further south, the trend for perhaps more snow and sleet rather than
freezing rain and ice has increased, but freezing rain and sleet
will initially be a problem along and south of the I-10/Highway 90
corridor this evening. With temperatures a few degrees colder this
afternoon than previously forecast, due in part to the earlier cloud
cover, freezing drizzle/rain may start as early as 5 or 6pm this
evening. In any matter, with a very dry dendritic growth zone in the
-10 to -20C layer, precip will be highly dependent on temperatures
between the sfc and 700mb. There is still a subtle warm nose at the
700-750mb level, which will result in more freezing drizzle and rain
earlier on, mainly before midnight. After that, most precip should
come in the form of sleet/snow but some freezing drizzle may still
mix in. We expect between a trace to .10" of ice accumulation south
of the I-10 Corridor.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or 
.
