Area Forecast Discussion
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FXUS64 KLUB 221712
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1212 PM CDT Thu Jun 22 2017

.AVIATION...
Thunderstorms are expected again tonight moving out of eastern New
Mexico. However, confidence in coverage and timing is too low to
mention in the TAF. Otherwise, VFR is expected.

&&

PREV DISCUSSION... /issued 415 AM CDT Thu Jun 22 2017/

DISCUSSION...
Notable changes with this forecast consisted of nudging highs
even hotter today, accelerating a mostly dry cold FROPA across
the area Friday morning and afternoon, and also lowering max
temps considerably this weekend under a protracted period of
post-frontal stratus and unsettled northwest flow.

Today and tonight: 00Z upper air analyses revealed a 700 mb
thermal ridge of 19C to 21C from Albuquerque to Denver. This
layer will shift closer to our domain today under continued N-NW
flow around an upper high still wobbling over southern AZ.
Nocturnal convection was fading faster than the past two mornings,
due in large part to the theta-E ridge being shunted west toward
the NM state line ahead of much lower dewpoints off the Caprock.
Overnight light rains will have little impact on highs today, with
many locales expected to easily crack 100 degrees as temps from
850-700 mb rise 2-4 degrees. Some locales near the NM border may
threaten heat advisory levels (105-109 degrees), but this is
expected to be too localized to warrant headlines at this time.
Aforementioned warming aloft could hinder the vitality of another
round of late day storms likely to fire in the western Panhandle
along a stationary surface trough, but many models agree in
convection surviving into the South Plains after sunset, before
decaying after midnight. Downbursts will again be the principle
threat with this activity.

Friday and Friday night: As broad troughing becomes carved out
over much of the Great Plains on Friday, a cold front will motor
south across the Panhandle near daybreak. Even during the warm
season, models suffer a slow bias with healthy cold fronts on the
flat High Plains, so this forecast was weighted toward a faster
FROPA and unfortunately lower PoPs Friday afternoon as we expect
the boundary to be exiting our southern zones near peak heating.
Still, a narrow corridor of severe potential exists near and just
behind the front as around 2000 J/kg MLCAPE becomes collocated
with up to 35 knots of deep layer shear. Many CAMs focus
convective initiation near the front and dryline intersection from
Yoakum to Lea County which makes meteorological sense. Well
behind the front by Fri night, marginally cyclonic upper flow and
stronger northwesterlies high aloft are progged to bolster
isentropic ascent. For now, the brunt of this elevated lift looks
to target the southeast Panhandle into the northern Rolling
Plains.

Weekend: Despite cool surface ridging and ample low clouds on
easterly upslope winds, the pattern remains favorable for elevated
showers and storms within an unsettled NW flow regime. Highest
PoPs continue to be favored overnight given the low level jet`s
contribution to isentropic ascent. Lack of discernible impulses or
further foci for lift is reason enough to keep PoPs below likelies
for now. Soundings show PWATs ranging from 1.25 to 1.75 inches
this weekend with elevated CAPE too low for severe prospects, so
some heavy rain at times will be the greatest threat especially if
training convection emerges. WPC`s QPF for Sat night alludes to
this concern nicely.

Monday through Wednesday: The Desert SW high is favored to
expand zonally, but slowly deamplify in the process. This implies
our area would not dry out as fast as originally expected, with
some semblance of NW flow still lingering through much of the
final week of June. Opted to extend low PoPs through at least Tue
while ramping up max temps much closer to climo by Wed.

&&

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

$$

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