Overnight forecast discussion for long term from FWD.
.LONG TERM... /Issued 328 AM CST Mon Jan 6 2025/
/Tuesday Night and Beyond/
Confidence continues to increase in a potentially impactful winter
storm across much of North and Central Texas during the second
half of the work week. By Tuesday night, an impressive upper-level
low will sink south toward Baja California setting the stage for
what could be quite the snow event across much of the region.
Climatologically, this upper-level pattern favors more long
duration, large areal coverage snow events across North and
Central Texas with a near continuous supply of 700mb-500mb Pacific
moisture streaming overhead from the southwest. This Pacific fetch
of moisture content keeps the dendritic growth zone saturated, a
layer in the atmosphere between -12C and -18C favorable for ice
crystal development and growth. A very dry layer of air beneath
700mb will prevent any precipitation from reaching the ground
until we tap into a southeast-northwest oriented plume of 850mb
Gulf moisture Wednesday evening.
So, we will have the moisture and we will have the lift. Now we
just need temperatures to be cold enough through entire
atmospheric column to produce snow. And here in Texas, we are used
to our winter weather events being a game of just a few degrees,
because as we know slightly colder or slightly warmer temperatures
can lead to drastically different final results. At this time,
ensemble and deterministic guidance favors temperatures profiles
supportive of snow across much of North Texas and a rain-snow mix
over Central Texas with a deepening surface low along the Texas
Coast keeping cold, northerly low-level flow over our forecast
area. This Baja California cut-off low synoptic setup is known for
having warmer temperatures aloft which could bring some warm-nose,
wintry mix action to locations south of I-20. Right now, this
layer (if to materialize) looks shallow and cool enough to support
primarily sleet rather than freezing rain. Still can`t rule a
light glazing in portions of our Central Texas and Brazos Valley
counties.
The devil is in the details, so let`s break it down:
Timing: Although some models try to start wintry precipitation in
our western North and Central counties early Wednesday afternoon,
the vast majority of guidance starts our event later Wednesday
evening into Wednesday night. Precipitation will overspread much
of our area from southwest to northeast during the day Thursday
exiting to the east Friday morning.
Amounts: Confidence is growing that a large portion of our
forecast area will see impactful snow accumulations. The most
likely amounts now range from 2-4" generally from the Red River
down toward a Goldthwaite-Hillsboro-Canton line. Higher totals are
certainly possible within this area with a 30-40% chance that
totals exceed 6" through Friday morning. Lower totals are expected
down in the Brazos Valley and the Killeen-Temple MSA with a
~30-40% chance that this area misses out on the snow event
entirely.
Type: It is still a bit too early to be confident in the
precipitation type and precisely where and when
rain/snow/sleet/freezing rain will occur. We are entering the
range of some medium-range guidance and will soon gain access to
high-resolution guidance that will help us make these distinctions
over the next 2-3 days.
Other than that, expect highs in the 30s Wednesday and Thursday
with a gradual warm-up into the 40s this weekend. Overnight lows
will dip into the 20s each night with lows in the 30s increasingly
possible by Friday morning. Stay warm, bundle up, and prepare for
an increasingly likely impactful winter weather event later this
week!
Langfeld