Drought in Texas, January 1, 2022

Area Forecast Discussion
National Weather Service Lubbock TX
1043 PM CST Fri Dec 31 2021

.AVIATION...
Periods of light rain will continue through much of tonight and
will begin to decrease from southwest to northeast by early
tomorrow morning. CIGs are expected to remain VFR throughout the
period; however, there may be times that lower ceilings and rain
may result in MVRF conditions. A low-level jet will form tonight,
resulting in LLWS at all terminals through tomorrow morning.
Clouds will briefly move out late tomorrow morning before the next
system brings additional low clouds, a northerly wind shift, and
the potential for snow to the end of this forecast period.

&&

. PREV DISCUSSION... /issued 245 PM CST Fri Dec 31 2021/

SHORT TERM...
Warm, moist mid level ascent well downstream from an upper level low
located over Baja California is resulting in fairly widespread light
rainfall across the forecast area this afternoon. That mechanism is
expected to continue to produce light rain through the evening
hours, likely refocusing across the southeastern third of the
forecast area before shifting to the east. Meanwhile the upper low
will open up and race to the east-northeast, crossing southwestern
New Mexico late this evening and then to a position over the eastern
Panhandle by sunrise Saturday. Mid-level lift associated with the
upper trough supported by the entrance region of a 140 kt 250 mb
jet streak should bring another round of rainfall to the forecast
area tonight as fairly rich mid level moisture will continue to be
tapped. Rainfall amounts should be mostly limited to 1/10 inch or
less for this overnight event as the rain should race northeastward
with the parent lift, but some individual elements may have some
heavier rain in them that could bring some locations 1/4 inch or
more.

Precip and cloud cover should clear quickly behind the departing
trough early Saturday. That in turn should unleash a modified arctic
air mass southward down the High Plains. As is typical of this type
of air mass, the expectation is that the models are a bit slow with
its progression through the forecast area, and have accelerated it
about two hours relative to the WRF-NAM, HRRR, etc. The fact that
there is another upper level short wave trough approaching from the
northwest and fairly stiff flow not far off the deck will exist
overhead downstream from said upper trough may inhibit the southward
progress some, but typically the density of the cold air mass wins
out. Temperatures will decrease with the frontal passage, possibly
not too fast initially as skies should be mostly sunny, but as
stratus fills in behind the front and as altocumulus spreads
overhead in advance of the upper trough the rate of decline should
accelerate.

LONG TERM...
Wintry precipitation chances will increase tomorrow afternoon
following the front, with a quick transition from plain rain to snow
due to the sharply baroclinic state of the mid/upper-level trough
pivoting into the southern Great Plains. Vertical thermodynamic
profiles that are initially saturated with >=0 deg C wet-bulb
temperatures across the southern South and Rolling Plains will
quickly become supersaturated with respect to ice due to intense CAA
in wake of the Arctic front, leaving a short window for plain rain
before transitioning to light snow with this second round of
precipitation this weekend. Snow will begin to quickly come to an
end from west-to-east on Saturday night into Sunday morning as the
highly progressive mid/upper-level trough pivots eastward. Forecast
vertical thermodynamic profiles by 02/00Z along and east of the I-27
corridor are also saturated with respect to water with wet-bulb
temperatures well below 0 deg C (supersaturated with respect to ice)
while drying out in the mid-levels quickly with westward and
northwestward extent as NVA increases upstream. The best Q-vector
convergence is forecast to be focused across portions of the central
South Plains and into the Rolling Plains between 02/00-06Z, though
the fast progression of the positively-tilted mid/upper-level trough
is not particularly favorable for enhanced CSI, and therefore
deformation banding, though slantwise parcel trajectories within the
zone of low- and mid-level frontogenesis will result in the
formation of pseudo-bands or snow squalls within the post-frontal
airmass. However, any development of such pseudo-bands/squalls will
be ephemeral as the columns dry out entirely from increasing NVA and
as the Arctic front surges into far southern Texas by sunrise
Sunday, with the precipitation shield moving via advection from the
the mean flow aloft. Where exactly these weak, pseudo-bands/squalls
of snow develop is uncertain as it is contingent upon the evolution
of the aforementioned meso-beta-scale elements, with upper echelon
snow accumulations around 1.0" forecast at most in areas that
experience pseudo-banding/squalls with generally a light coating
elsewhere across the Caprock and Rolling Plains.

Temperatures are expected to fall into the single digits across the
extreme southwestern Texas Panhandle, while into the lower-middle
teens elsewhere across the South and Rolling Plains with a north
wind at around 15-20 mph. This will result in wind chill values
around 0 deg F to -5 deg F, and confidence is not high enough at
this time to issue a Wind Chill Advisory for Sunday morning. Surface
winds will back to the west by Sunday afternoon as the departing
southern-stream mid/upper-level trough becomes neutrally-tilted and
begins to deamplify, with a broad, 1030 mb surface anticyclone
developing across the central and southern Great Plains. Highs will
rebound rather quickly given the magnitude of the cA airmass that
advected into the region earlier in the day, with temperatures
peaking in the middle 40s area-wide beneath a clear sky.

Relatively quiet weather is expected heading into the early and
middle portion of next week as the zonal flow develops across the
central CONUS, with high temperatures climbing into the lower-to-
upper 60s by Tuesday and Wednesday, though elevated to critical fire
weather conditions will be possible Tuesday afternoon across the
region. Another cold front is forecast to move through on Thursday
as a full-latitude trough encompasses the lower 48, though
temperatures should rebound as the amplitude of the upper air
pattern attenuates back to a quasi-zonal state.

Sincavage

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&

07/09/10

Hazardous Weather Outlook...UPDATED
National Weather Service Lubbock TX
240 PM CST Fri Dec 31 2021

TXZ021>044-012045-
Parmer-Castro-Swisher-Briscoe-Hall-Childress-Bailey-Lamb-Hale-Floyd-
Motley-Cottle-Cochran-Hockley-Lubbock-Crosby-Dickens-King-Yoakum-
Terry-Lynn-Garza-Kent-Stonewall-
240 PM CST Fri Dec 31 2021

This Hazardous Weather Outlook is for the South Plains, Rolling
Plains and the far Southern Texas Panhandle.

.DAY ONE...This afternoon and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

A strong cold front will pass through the area late Saturday morning,
leading to falling temperatures through the afternoon and breezy
northerly winds. The combination of the two will lead to very cold
wind chill values potentially as low as 5 degrees below zero across
the far southwestern Texas Panhandle and northwestern South Plains
by early Sunday morning.

Light snow is forecast to occur on Saturday afternoon and night,
leading to low accumulations generally under a half inch, although
localized areas may see snowfall accumulations around an inch. This
may lead to slick, icy roadways Saturday evening into Sunday
morning.

Elevated to critical fire weather conditions will be possible
Tuesday afternoon as warmer and drier conditions return to the
region.

Beyond Tuesday, the probability for widespread hazardous weather is
low.