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000
FXUS64 KLUB 202339
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
639 PM CDT Fri Oct 20 2017

.AVIATION...
VFR conditions this evening will likely yield to MVFR ceilings (and
possibly IFR) after midnight tonight as southerly breezes advect
increased moisture into the region. Confidence in IFR conditions
are greatest at KLBB where a TEMPO was included. The low clouds
will lift/scatter by mid to late Saturday morning with VFR through
the afternoon. Southerly breezes overnight will veer westerly on
the Caprock at elevated levels Saturday afternoon. KCDS will have
a chance of a late day storm tomorrow, though the better chances
may reside further to the east. Additionally, a cold front will
shift the winds to the north near or just beyond the end of the
TAF cycle.

&&

.PREV DISCUSSION... /issued 327 PM CDT Fri Oct 20 2017/

DISCUSSION...
Mid-level subsidence was firmly in control of the region this
afternoon following a compact upper low currently crossing the
Wichita Mountains. Farther west, surface troughing will remain
poised across eastern NM through the night and keep breezy
southerly winds intact. This will serve to pull richer Gulf
moisture northward and even foster some low cloud development
before daybreak. By late morning, southwesterly flow will amplify
ahead of digging trough across the Four Corners, ultimately
driving the surface trough east across the South Plains. This
trough should assume a weak dryline structure by peak heating just
east of the Caprock. Although surface convergence is shown to be
rather lackluster, modest height falls with the approaching upper
trough could breed a few storms by early afternoon off the
Caprock. This ascent will only improve once a cold front dives
south from the Panhandle by late afternoon and bolsters
convergence within the moist sector. SBCAPEs of nearly 1500 J/kg
across our far eastern column of counties could easily support
some severe storms, but swift storm motions of 35-40 knots should
hasten their departure out of our eastern counties by the evening
hours.

Following Saturday`s trough, a protracted period of uneventful NW
flow will dominate much of the Great Plains through the upcoming
week. Sunday looks to be stellar as a dry surface ridge camps out
under full sun and light winds, but this ridge will exit Sunday
night ahead of another cold front for Monday followed by
progressive surface ridging. Overall, models and ensembles are
converging nicely towards a strongly positive PNA regime by mid-
to-late week as Pacific ridging amplifies considerably through the
Gulf of Alaska. Such meridional patterns are ideal for a deluge
of cP air through the Great Plains, and this appears to be the
case by Thursday or Friday complete with unseasonably cool
temperatures. Superblend reflects this temperature change well for
now, but should raw models continue to prog sub-zero 850 mb temps
by late week, then this would require considerable adjustments
lower in later forecasts.

&&

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

$$

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