Winter Weather in Texas, January 5 to 6, 2017

Area Forecast Discussion
National Weather Service Lubbock TX
526 PM CST Thu Jan 5 2017

.AVIATION...
An upper level storm system approaching the region will bring
chances of snow showers to all TAF sites beginning early Friday
morning and lasting through Friday afternoon. However, chances
will be greatest at KCDS for accumulating snowfall. Visbys and
CIGS will likely decrease to at least MVFR during periods of
snowfall.

&&

.PREV DISCUSSION... /issued 318 PM CST Thu Jan 5 2017/

SHORT TERM...
An upper level trough will slowly sag across the Panhandle later
tonight, and the South Plains Friday, with a notable band of
frontogenetic forcing in the mid levels around 750 to 700 millibars.
This forcing will be overlapped tonight by a jet streak crossing the
Panhandle and generating a snow band that solutions agree will
produce perhaps one to three inches of snow along our northern row
of counties. But there could be a very sharp delineation between
snow and no snow, so a slight north or south adjustment of the jet
streak would be significant. Another notable upper level jet will
stretch eastward across our southern counties Friday with still
enough remnant frontogenetic forcing for snow chances spreading
through central and southern counties, too. Snow is clearly favored
in this pattern. And the lift associated with the jetlets and fronto-
forcing also is in decent agreement, other than precise placement.

Our biggest concern with snow totals this event involves the dry
lower atmosphere, say in the lowest 2000 to 3000 feet. We are
starting out very dry with dewpoint depressions of 20 to 25 degrees.
A low level northeast to easterly component will not lead to
significant moistening other than perhaps along the immediate edge of
the Caprock escarpment; the upstream trajectories are just too dry.
So, moistening in the lower levels will have to occur top-down from
precipitation processes aloft. The 12z GFS was notably more damp
across central and southern counties on Friday than the 12z WRF/NAM,
while the TTU/WRF also was trending a bit wetter. Our forecast was
leaned additionally to the slightly snowier ensemble methods favored
by the WPC. So, we have upped snow amounts slightly while favoring
our northern zones as previously. Amounts are enough for us to issue
a Winter Weather Advisory for our northern tier of counties. Will
let later shifts assess if this is needed to be expanded any to the
south. Also, we added a Wind Chill Advisory for our northwest zones
with forecast wind chills near or a little less than minus 5 later
tonight and early Friday in our northwest.

Snow totals further south into the central and southern South Plains
remain tied in to the potential moistening (or lack of) in lower
levels. Due to high levels of uncertainty, we will retain a low-end
snow total forecast with more moderate snow probabilities as well,
although with frozen:liquid ratios around 16:1 it may not take
much to accumulate a half inch or more. Little adjustment to
previous temperatures; i.e. just cold. RMcQueen

LONG TERM...
After all of the excitement in the short term, quiet weather will be
the rule in the extended. Any lingering light snow showers or
flurries will quickly come to an end by Friday evening. Clearing
skies and light winds will lead to a chilly night, and where there
is snow on the ground (most likely across the Texas Panhandle)
temperatures will crater. Most spots should see lows by early
Saturday down into the single digits to around 10 to 13 degrees.
However, the far southwest Texas Panhandle could even dip below
zero, especially if there are a couple of inches of fresh snow on
the ground. These cold temperatures coupled with light breezes will
push wind chills down to 0 to -12F range across the northwest
zones Friday night, though the light winds (under 10 mph) will
likely preclude the need for a wind chill advisory. Either way it
will be/feel cold! Moreover, the forecast low of 8 degrees at
Lubbock on Saturday morning (January 7th) is only 2 degrees shy of
the record of 6 degrees, set back in 1968.

Upper ridging will follow the exiting shortwave trough Friday night
and persist into early next week. This will help provide a warming
trend. Initially the warm up will be slow, with lingering surface
ridging slow to exit. Highs will only climb into the mid-30s to
around 40 degrees on Saturday, with mid-40s to lower 50s expected on
Sunday. The cold surface high will finally move far enough east to
allow for a return of breezy, dry and more noticably warmer weather
early next week. Temperatures will jump into the upper 60s and lower
70s Monday afternoon. A passing upper level disturbance on Tuesday
will bring only modest mid-week cooling, though temperatures should
remain on the high side of average (highs mostly in the 60s behind
this wave). Aside from occasional passing high clouds in the
extended, dry conditions will be the rule.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 PM this evening to 3 PM CST
Friday for TXZ021>026.

Wind Chill Advisory from 9 PM this evening to 9 AM CST Friday
for TXZ021-022.

&&

01

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LUBBOCK TX
247 PM CST THU JAN 5 2017

TXZ021>044-062100-
PARMER-CASTRO-SWISHER-BRISCOE-HALL-CHILDRESS-BAILEY-LAMB-HALE-
FLOYD-MOTLEY-COTTLE-COCHRAN-HOCKLEY-LUBBOCK-CROSBY-DICKENS-KING-
YOAKUM-TERRY-LYNN-GARZA-KENT-STONEWALL-
247 PM CST THU JAN 5 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTH PLAINS...ROLLING
PLAINS AND THE FAR SOUTHERN TEXAS PANHANDLE.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SNOW ACCUMULATIONS OF 1 TO 3 INCHES ARE EXPECTED TONIGHT ACROSS
THE EXTREME SOUTHERN TEXAS PANHANDLE AND NORTHERN ROLLING PLAINS.
THE HIGHEST TOTALS ARE LIKELY NEAR THE CAPROCK ESCARPMENT, ESPECIALLY
OVER PARTS OF SWISHER AND HALL COUNTIES. HAZARDOUS DRIVING CONDITIONS
WILL RESULT. DANGEROUSLY LOW WIND CHILLS VALUES ALSO ARE EXPECTED AT
TIMES COLDER THAN 5 BELOW ZERO ACROSS THE EXTREME SOUTHWEST TEXAS
PANHANDLE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

LIGHT SNOW ACCUMULATIONS THAT BEGIN TONIGHT ARE EXPECTED TO
CONTINUE FRIDAY ACROSS THE EXTREME SOUTHERN TEXAS PANHANDLE AND
NORTHERN ROLLING PLAINS. THE DANGEROUSLY LOW WIND CHILLS SHOULD
GRADUALLY EASE BY LATE FRIDAY MORNING. LIGHT SNOW ACCUMULATIONS
LESS THAN AN INCH ARE POSSIBLE FRIDAY FOR MUCH OF THE SOUTH PLAINS
AND SOUTHERN ROLLING PLAINS. MANY AREA ROADS MAY BECOME SLICK
FROM THE LIGHT SNOWFALL BY OR SHORTLY AFTER DAYBREAK ON FRIDAY.
DANGEROUSLY COLD WIND CHILLS FROM MINUS 5 TO MINUS 10 MAY DEVELOP
FRIDAY NIGHT ACROSS THE SOUTHWEST PANHANDLE AND NORTHWESTERN SOUTH
PLAINS.