Area Forecast Discussion
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FXUS64 KLUB 311148
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
648 AM CDT WED AUG 31 2016

.AVIATION...
Low ceilings which were around 400-600 ft in the vicinity of KLBB
and KPVW are on a rising trend, but we could still see the ceilings
bounce around IFR or MVFR through about 14 UTC. Otherwise, we
expect scattered SHRA and isolated TSRA across the area most of
the day, but with low confidence on the timing of impacts at any
particular terminal. Surface winds will be mainly out of the
north to east and light in the absence of the showers. Low
ceilings may return to all terminals late tonight or early
Thursday morning.

&&

.PREV DISCUSSION... /issued 351 AM CDT WED AUG 31 2016/

SHORT TERM...
Deep moisture will continue to reside across the region today and
tonight. Precipitable water values range from about 1.5 to 2 inches
across the forecast area - or about two standard deviations above
normal for late August. Although the upper-level trough stretching
SW to NE across the region is slowly filling, and heights will rise
a bit to our south, the forecast area is still roughly located under
the right entrance region of a modest upper-level jet. Northeast to
easterly flow from the surface to 800 mb will provide moist upslope
flow and there appears to be a minor reinforcing surge to the
surface ridging coming in from the northeast later this evening.
Instability will be a bit of a question mark today, as we are likely
to see more extensive cloud cover then yesterday when we were able
to generate decent surface instability by mid-day. It may be a bit
tougher today with highs expected to be several degrees cooler -
perhaps not breaking out of the 70s across much of the western
areas.

Short-range guidance is in broad agreement that shower and t-storm
activity will once again be prevalent across the area - although the
highest rain chances will shift to an axis from east-central New
Mexico into northwest Okla., running across our western and northern
zones. Activity will likely be ongoing at daybreak along the TX/NM
state line, and is then expected to gradually expand eastward - with
more scattered activity developing in the Rolling Plains. Forecast
soundings suggest about 500-750 J/kg of MLCAPE to work with very
weak capping, again keeping in mind the uncertainty of the sky
cover. Very weak winds aloft below 300 mb indicate that storm motion
will continue to be dominated by outflow propagation. Individual
storm cells will be capable of producing very heavy downpours.

We did consider issuing a flash flood watch for today. However, it
appears that the main axis of precip for today will not align well
with areas that have received the most precip the past 48 hours or
so. The possible exception is across Bailey, Cochran, Lamb and
Hockley Counties of the western South Plains, and we will closely
follow the precip trends in that area as the soil across that area
is likely pretty saturated. Otherwise, we will continue to mention
the threat of locally heavy rain and flooding in the HWO.

Tonight, cloudy skies and rain chances will continue. There is some
indications that the best rain chances will shift north across the
far southern Texas Panhandle - but this is far from certain at this
point. We will continue to mention thunderstorms although thunder
will likely become more uncommon late in the evening.

LONG TERM...
The atmosphere is not quite ready to call it quits on the
precipitation chances to round out the week.

An extensive mid level moisture plume currently over the region
will pivot around the region as upper level ridging shifts to the
east for the rest of this week. The upper ridging will move east
while broad troughing moves into the western CONUS. Although we
will lose forcing from the upper level jet that has been stationed
to our west, models do indicate a few weak short waves within the
flow aloft. These disturbances may be enough to see increased
coverage of thunderstorms. Models tend to agree on one of these
short waves passing overhead on Thursday evening. A trend of
warming temperatures each afternoon will lead to a gradual
increase of instability each day. Mid level moisture will fade out
this weekend leaving only low level moisture for the atmosphere to
work with. So chances of storms will decrease this weekend with
the loss of deeper moisture. The broad upper level troughing over
the western CONUS this weekend into early next week will result in
the development of surface troughing in the lee of the Rockies.
This will mainly bring breezy winds locally.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

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