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FXUS64 KLUB 260823
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
323 AM CDT THU MAY 26 2016

.SHORT TERM...
Water vapor satellite loop shows that there is a weak shortwave
moving out across the Big Bend region of Texas early this morning
which is helping to fire off some thunderstorms around midnight
across the western Permian Basin. These storms have since
dissipated with the lone exception of a thunderstorm moving into
the western Concho Valley. We are also seeing some weak mid-level
reflectivity returns that are likely not reaching the ground
across the western South Plains early his morning as well. 00Z
upper-air analysis shows steep lapse rates across the forecast
area extending west across New Mexico all the way into eastern
California, and model forecast soundings show quite a bit of
elevated CAPE available across the region. The forecast for this
morning is going to be tricky as any lift from the shortwave may
result in additional development of showers or storms. Almost all
of the models do not have any precipitation development this
morning and because the chance for precipitation is highly
conditional, we will leave this out of the forecast for now.

The dryline continues to mix northwestward this morning but should
be stalling out shortly before once again making a march to the east
through the day.  As is usually the case, there are differences in
how far east the dryline will make it but all of the models agree
that it should make it into the eastern Rolling Plains.  Very few of
the high-resolution model runs this morning produce any convection
of significance across our forecast/warning area this afternoon and
this evening but the few that do have some pretty robust storms. The
most favored area will be across the southern Rolling Plains where
the best boundary layer moisture will be and cap strength the
weakest.  Shear profiles are favorable for organized convection and
a few supercells but the better chances appear to be outside of the
forecast area to the east and south.  A likely scenario is for
storms to initiate along the dryline in our forecast area and then
move east and strengthen as they do so.  Confidence is not all that
high that we will see severe storms in our area but will leave
mention in the weather grids for now.

Behind the dryline, a dry southwesterly wind will once again help
to bump temperatures up but not quite as warm as yesterday. The
slightly cooler high temperatures are due in part to heights
falling through the day as an upper level low over western Arizona
continues to slowly push east. Models continue to struggle with
how strong wind speeds will be this afternoon with the GFS MOS
guidance in 25 to 35 MPH range out of the southwest with the NAM
MOS 15 to 25 MPH. Deep mixing will take place behind the dryline
allowing some of the higher wind speeds aloft to transfer to the
surface, but not quite as strong as the GFS is suggesting. Models
do not mix the dryline as far west tonight into Friday morning
which will result in cooler morning low temperatures across the
northwestern South Plains and readings fairly close to what have
been reported the last couple of mornings for the remainder of the
area.

Jordan

.LONG TERM...
The extended will start on the quiet side but will trend toward
the unsettled late this weekend into next week. Initially on
Friday dry air will envelop the South Plains region on breezy
westerly winds south of a storm system emerging across the central
High Plains. Temperatures will moderate back down toward average
as the passing trough provides some cooling. There remains a low
threat a little high-based convection originating over the higher
terrain of New Mexico could make a run toward our northwest zones
late in the day but even if it were to make it amounts would be
spotty and light given the deep and dry sub-cloud layer.

A fine start to the holiday weekend will follow with relatively
light winds and dry conditions beneath relatively flat flow and a
progressive low-amplitude upper ridge. The dry conditions and plenty
of insolation will allow highs to peak around the 90 degree mark for
many spots on Saturday.

The upper flow will quickly transition to southwesterly Saturday
night into Sunday as the next storm system digs toward the Desert
Southwest while low-level moisture rapidly returns from the
center of the state. Under this pattern storm chances will quickly
return to West Texas on Sunday. The current round of NWP
advertises a fairly decent embedded disturbance traversing the
region late Sunday into early Monday complete with widespread and
locally heavy QPF generation. Beyond then, models diverge somewhat
on how things will evolve but they do keep relatively weak but
perturbed flow aloft while low-level moisture and instability
remain in the region. So although there will undoubtedly be lulls
in precipitation, there should also be decent periodic chances of
showers and thunderstorms too. Given this we have accepted the
blend guidance that carries solid chance PoPs through the middle
of next week. As alluded too, the dynamics will be on the weaker
side, but with moderate to strong instability present during the
afternoon and evening hours, occasional robust updrafts will
occur. Additionally, slow storm motions and fairly rich moisture
will support locally heavy rainfall at times. To go along with
the increased moisture and rain chances, temperatures will trend
downward to or even a little below average. All said, the overall
forecast remains on track with only minor adjustments made this
iteration.

&&

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

$$

14/23



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