Area Forecast Discussion
Issued by NWS

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FXUS64 KLUB 162343

Area Forecast Discussion
National Weather Service Lubbock TX
643 PM CDT Sat Sep 16 2017

Thunderstorms are roaming near/over all three terminals to kick
off the TAF cycle. Storms over KLBB should quickly shift east of
the terminal, though they could persist another 1-3 hours at KPVW
and KCDS. Expect gusty and erratic winds and brief heavy rain (and
associated reduced visibilities) with the strongest cores. More
isolated showers and thunderstorms will be possible late tonight
into Sunday morning, with scattered redevelop Sunday afternoon.
Timing and coverage of convection beyond this evening`s round is
uncertain and has been excluded from the TAFs at this time.
Outside of any storm influences VFR and relatively light (though
somewhat variable) winds will be the rule.


.PREV DISCUSSION... /issued 341 PM CDT Sat Sep 16 2017/

Unsettled SW flow aloft looks on track for another round of
isolated to scattered storms later today and overnight. Water
vapor imagery indicated a narrow dark axis (subsidence) extending
from near El Paso northeast to Amarillo, which aligns well with
the northern terminus of an upper jet. This jet coincides nicely
with a surface trough and ample surface heating (0-3 km lapse
rates as steep as 10*C) which has brewed SBCAPEs of 500-1000 J/kg
thus far. Agitated cumulus have blossomed along this axis of
strong heating, with maturation to storms noted near Levelland as
of 310 PM. Greater coverage of storms in Lea County, NM could
prove to be the bigger show locally as 20-30 knots of steering
flow sends this activity into the South Plains through the evening.
Feeling is the HRRR remains overblown with coverage of precip,
but the overall scenario of storms tracking NE and focusing near
the aforementioned surface trough appears very plausible. Healthy
DCAPE of nearly 1500 J/kg will favor microbursts with some of the
stronger cores, which was addressed well in the midnight shift`s
HWO. With no real upper trough evident overnight, convection
may not wane much at all after midnight thanks to the lingering
upper jet.

SW flow aloft will veer a bit more W-SW on Sunday as an elongated
ridge retrogrades from the Gulf to South TX. Upshot of this is
that the mid-level moist axis, surface trough, and upper jet
should all be nudged farther north into the Panhandle, but remain
close enough to warrant additional PoPs for much of our region. By
Monday, drier westerly flow should vaporize a large extent of the
elevated moisture plume and serve to ratchet high temps up. This
warming looks most pronounced on Tuesday as most of the CWA
resides west of a surface trough/weak dryline complete with 15-20
mph downslope winds. Max temps were edged higher Tuesday, but
could see some respectable cooling by Wednesday as a dry cold
front dives south. This front will be tied to a lead trough ejecting
from a longwave trough poised to dominate much of the western
CONUS by late next week. Barring some conditional PoPs along the
trough/dryline Tuesday in our Low Rolling Plains` counties, the
more definitive push of deeper moisture should evolve by Thursday
and beyond as the upper flow trends more meridional ahead of the
digging trough to our west. GEFS members exhibit surprisingly good
clustering with this regime which is befitting of high chance PoPs
regionally for Friday and Saturday, along with cooler high temps.




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