Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KLUB 160543
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1143 PM CST Sun Jan 15 2017

.AVIATION...
We expect IFR conditions to prevail at all the terminals through
about 15 UTC Sunday morning, but we could see periods of MVFR to
VFR conditions beforehand, as confidence on ceiling height is
low. A final round of -SHRA will move through KCDS in the first
few hours of the TAF, shaking up Ceilings and visibility in that
area. Otherwise, VFR conditions should return by 15 or 16 UTC,
then continue through the remainder of the period. Low ceilings
may redevelop right around the end of the TAF 17/06 UTC.

&&

.PREV DISCUSSION... /issued 1049 PM CST Sun Jan 15 2017/

UPDATE...
We did decided to go ahead and issue and short-fused winter
weather advisory for Parmer, Castro and Swisher Counties until
08Z. Calls to the Friona PD and Dimmitt SO reveal that the
precipitation has recently changed over to heavy wet snow,
at least across the northern portions of the counties. Roads in
northwest Castro County were becoming snow covered and slick, with
the heaviest snow also dropping the visibility significantly.
Given at least some slick roads already developing across this
area it seemed prudent to issued the winter weather advisory. The
snow should quickly come to an end by 1 or 2 am as the upper low
forcing the snow band shifts off to the northeast of the area.
Before then, some spots over the northern portions of the advisory
could pick up a quick inch or two of snow.

PREV DISCUSSION... /issued 936 PM CST Sun Jan 15 2017/

UPDATE...
Final round of lift associated with the center of the upper low
now spinning across the South Plains was bringing a renewed area
of light to moderate rain across the central and southern South
Plains. This activity should quickly shift northeastward into the
Rolling Plains and southeast Texas Panhandle before moving out of
the CWA shortly after midnight. In addition, a band of light to
moderate rain within the deformation region of the upper low will
linger across the northwest/north-central zones until shortly
after midnight too. This area could even see the rain briefly
change to sleet and snow as the elevated warm-nose cools with the
passage of the low, before any precipitation comes to an end
shortly after midnight. Light sleet/snow accumulations, generally
under an inch, may occur across the far southwest Texas Panhandle,
though with the wet ground and marginal surface temperatures we
don`t expect significant impacts. Grids have been updated to
better depict the current and expected radar/precipitation trends
over the next several hours. Additionally, minor adjustments to
the temperature, dewpoint and wind grids were made taking in
recent observations and trends. No other changes were made to the
ongoing forecast at this time.

PREV DISCUSSION... /issued 615 PM CST Sun Jan 15 2017/

AVIATION...
Low ceilings and visibilities resulting in IFR conditions, will
likely continue through much of the night, although drier air
moving in from the west may lead to some improvement at KLBB and
KPVW. A return to VFR conditions should occur mid to late Monday
morning, with low confidence in the precise timing.

PREV DISCUSSION... /issued 325 PM CST Sun Jan 15 2017/

DISCUSSION...
Compact upper low early this afternoon continued to churn slowly
east to near the Davis Mountains. Leading edge of strong height
falls and colder temps aloft was bisecting our CWA from N-S at 3 PM
complete with a respectable line of elevated thunderstorms for
January standards. Unfortunately, rain rates with this convection
have been very lackluster and with no uptick foreseen, heavy rain
mention was removed from the forecast today. A decent stratiform
wake region of rainfall has actually yielded better precip rates
than the leading edge of storms, with forcing for this aided by
strong upper diffluence centered squarely over the western South
Plains. However, progressive mid-level dry slotting will erode
this deeper saturation with relative ease, but this has yet to
occur in Friona where light sleet was recently observed.

As convection exits the Rolling Plains this evening, attention will
shift to the upper low tracking northeast from near Lubbock to
Childress after midnight. Models show varying degrees of precip
redeveloping in this low`s deformation zone, but following mid-level
dry slotting there is a common model theme involving next to no
saturation in the dendritic growth zone aloft. Although low clouds
should remain largely undisturbed through the night, the critical
snow growth layer is progged to remain dry on model soundings in our
N-NW zones. This would yield mostly rain and/or drizzle, but we will
allow some latitude for very light snow accumulations in our far
southwest Panhandle counties should dry slotting be less effective
than models indicate.

Low clouds and perhaps some stubborn fog overnight will finally
scour out by mid-late morning on MLK Day with high temps returning
to climo territory. In the wake of tonight`s upper low, additional
PVA will be directed across the Desert SW and establish an
elongated trough axis. Deep moisture voids should preclude much in
the way of any sensible weather with this saggy trough, but Gulf
moisture could return far enough north for some light rain in our
SE zones by Tue night. Otherwise, milder highs through mid-week
with breezier SW winds will be the overwhelming story.

By late week, models favor a pair of moist Pacific troughs to
translate through the Desert SW with some implications for precip
and cooler weather. The first of these waves still looks to pass
to our north o/a Friday with robust SW winds at the surface,
before better moistening of the column ensues for the second
trough sometime during the weekend.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 2 AM CST Monday for TXZ021>023.

&&

$$

33


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.