Area Forecast Discussion
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719
FXUS64 KLUB 232346
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
646 PM CDT Thu Mar 23 2017

.AVIATION...
Strong southerly winds have occasionally knocked visibilities to
MVFR levels at KLBB and KPVW through the afternoon and this could
persist into the evening hours. Winds should gradually back off
late this evening after shifting southwesterly behind a Pacific
FROPA. Before then, we will see a narrow window for convection at
KLBB and KPVW around 01-03Z and at KCDS from 04-06Z. The greatest
threat with any convection will be strong/severe winds, though
pockets of hail will also be possible. The AWW continues at KLBB
until 02Z. Breezy southwesterly winds late tonight through early
Friday will again increase while veering westerly and then
northwesterly during the day. More BLDU is likely with MVFR to IFR
visibilities possible. Another AWW will likely be needed at KLBB
from mid-late morning through Friday afternoon before winds
finally weaken more substantially Friday evening. In addition to
another round of wind and dust Friday, a few showers could
potentially affect the northern terminals though the better shot
will be further to the north.

&&

.PREV DISCUSSION... /issued 332 PM CDT Thu Mar 23 2017/

SHORT TERM...
The forecast for late afternoon and evening remains largely on
track. Southerly winds are now generally in the 30 to 35 mph range
across the South Plains with gusts in the mid 40s according to
stations of the West Texas Mesonet. Blowing dust is being reported
at Plainview and Lubbock as well as on webcams across the area. The
dryline is just beginning to firm up just west of the state line -
which is a little bit farther west than previously indicated. The
dryline is still expect to mix into our counties bordering NM in the
next two hours before stalling out for a short time through early
evening. Most of the high-res and convective allowing models still
indicate isolated to widely scattered t-storm development near the
dryline between 5 and 7 pm, with coverage favoring northern areas.
CAPE and shear values support a threat of severe wind and hail at
least initially with the storms with storms that will be moving
quickly northeast at 40 to 50 mph. As the pacific front merges with
the dryline this evening, the storms should form a rough north to
south line, possibly in the vicinity of the I-27/U.S. 87 corridor.
There is still some question if there will be increasing spacing
between the cells farther to the south - more removed from the upper
forcing. Also, severe chances will likely decrease as the line moves
east, but if there is good cold pool organization along the line,
the severe wind threat could continue into the Rolling Plains.

The line should be east of our forecast area by about 1 am. Then our
attention will turn to the wrapped-up compact upper low moving across
the panhandles on Friday. A strong mid-level gradient will pass
southeast across our forecast are during the day and this will
support another round of windy conditions - this time from the west
to northwest. Guidance has fairly consistently showing wind speeds
near wind wind criteria, 40-45 mph, developing across much of our
area during the day. We continue with the High Wind Watch for our
northern counties where we have the most confidence in warning-level
winds. More blowing dust is expected although we`ll have to see if
rainfall this evening can influence tomorrow`s dust generation. The
northwest winds will bring in cooler air, high temperatures Friday
are expected to range from the low 60s northwest to middle 70s
southeast. We were tempted to add a mention of rain showers to the
far southwest TX Panhandle on Friday as the moisture wraps around
the upper low along with a pocket of cold pocket aloft providing
elevated instability. However, while we should see some clouds, the
chance of any meaningful precip looks pretty slim at this time.

LONG TERM...
The long term promises a reprieve from windy conditions beginning
Saturday, before assuming an unsettled and wet theme towards the
middle of next week. Stout NW gradient winds early on Friday evening
will scale back considerably overnight as the filling upper cyclone
moves toward the Ozarks and allows surface ridging to expand south.
This ridge will be quick to exit the region by midday Saturday under
progressive ridging and milder thicknesses. Such a progressive upper
flow will not allow sufficient moisture to return to the CWA on
Sunday when an open trough tracks mostly N of the region. What
moisture does return will be quickly shunted toward I-35 where late
day storms are favored. Our domain will be fall under breezy and dry
westerly flow on Sunday with valid wildfire concerns given only
light antecedent precip from tonight`s PoPs.

Next week, wildfire concerns could be dealt a fatal blow for some
time to come as models remain in good agreement with closing off
a large, slow-moving low in the Desert SW. This pattern fits the
bill for episodic regional rainfall, but the finer details such as
the speed and track of the upper low, dry slotting, and the rate
of moisture return following Sunday`s dry FROPA will obviously
impact rain distribution and amounts. Such details will become
more definitive in later forecasts, but for now the large scale
pattern warrants a multi-period blanket of PoPs beginning Tue.

Fire Weather...
As the dryline mixes across the state line late this afternoon, red
flag conditions are likely to develop for those counties. Also, the
dryline may advance into western portions of Castro and Lamb
Counties. High-based t-storms may also develop along the dryline and
bring the threat of dry lightning. A Red Flag Warning is in effect
for these areas through 9 pm this evening.

A dry pacific-type front will pass across the area tonight and
moisture recovery will be poor. During the day Friday, a tight
pressure gradient will develop across the area as an upper level
storm system crosses the Panhandles. This will produce very strong
winds during the day. Cooler temperatures and some moisture wrapping
south around the storm system should preclude critical fire
conditions across our northern counties, but RH values may drop into
critical territory across the south. Wetting rains are possible this
evening although at this time our confidence in widespread rain is
not strong. A Fire Weather Watch remains in effect for the southern
half of the area Friday.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Friday morning through Friday evening
for TXZ033>044.

Wind Advisory until 9 PM CDT this evening for TXZ021>044.

Red Flag Warning until 9 PM CDT this evening for TXZ021-022-027-
028-033-039.

High Wind Watch from Friday morning through Friday evening for
TXZ021>032.

&&

$$

33/93/23



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