Area Forecast Discussion
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FXUS64 KLUB 152333 AAA

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
533 PM CST Wed Feb 15 2017

VFR conditions will continue through the next 24 hours.  Jordan


.PREV DISCUSSION... /issued 323 PM CST Wed Feb 15 2017/

A surface ridge is objectively analyzed this afternoon across
northwest Texas with a lee side trough taking shape in eastern New
Mexico. Winds across the South Plains still under the influence of
the anticyclone this evening will gradually back to the southwest by
daybreak Thursday then strengthen a bit as surface gradient
increases. Expect clear skies overnight to continue through much of
the day Thursday before some high level cirrus begins to encroach on
West Texas in advance of upper low lifting northeast out of Mexico.
Daytime blended temperatures look in the ballpark but did boost them
a couple of degrees on the Caprock with compressional warming
expected to add a degree or two under full insolation.

Minimal changes were necessary to the inherited extended forecast.
The large scale theme over the southern CONUS will feature a pair of
slow, but progressive upper lows affecting the Lone Star State - the
first of which will be devoid of moisture except in the form of
cirrus as it lifts northeast from the Big Bend Region Thu night,
followed by a more amplified and moisture laden system for Sunday.

Friday still has the best potential for unseasonable warmth as W-NW
downslope winds accelerate to 15-20 mph in response to a 700 mb
trough digging through the Panhandle. This trough will drive a
surface wave south from the Panhandle by late in the day before
stalling in the Concho Valley come early Saturday. In its wake, a
weak backdoor cold front will replace downslope winds with
easterly upslope winds by midday Saturday. Even though upper
heights build within a progressive upper ridge and 24-hour delta
thicknesses change very little, easterly upslope winds versus
downslope winds should still temper highs by a couple degrees
compared to Friday.

Exodus of the upper ridge by Sat night ahead of backing upper flow
and height falls will spur a northwestward surge of Gulf moisture
over much of West TX. Deepening meridional flow by Sun fits the bill
for a wet and unsettled day in advance of an elongated upper trough
and upper low - the latter tracking well to our south. This southerly
displacement raises some concern over the duration of quality
ascent over the South Plains, particularly by late Sun as a 110+
knot upper jet undergoes rapid decay. Rapid mid-level drying in
close proximity to the approaching upper trough axis would also
deter a longer precip event from panning out. Regardless,
ensembles agree well in focusing a broad region of PWATs at or
above 0.75" on Sun before this drying ensues. PoPs were nudged up
area wide, with the highest chances favored off the Caprock where
models forecast PWATs breaching 1". Soundings throughout the day
on Sun show sufficient CAPE for thunder, but poor lapse rates
aloft courtesy of such moist meridional flow should keep the door
closed to severe modes in our domain. Deeper drying of the column
on Mon within the trough axis should end precip chances over all
but our eastern zones before ridging resumes aloft through midweek.



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