Area Forecast Discussion
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FXUS64 KLUB 262039
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
339 PM CDT Wed Apr 26 2017

.SHORT TERM...
Another springtime wind storm is on tap for Thursday as shortwave
energy now over the Pacific Northwest digs into the Oklahoma
Panhandle by early tomorrow afternoon. This will effectively tighten
height gradients resulting in westerly winds pushing wind advisory
criteria especially across the southwest Panhandle and northwest
South Plains. Unlike Monday there doesn`t appear to be a substantial
amount of mid and upper level moisture with the system to limit deep
mixing. Expect daytime highs to jump well into the 80s with
afternoon RH values again in the lower teens. This combination would
otherwise raise concerns for enhanced wildfire threat however as
noted yesterday, ERC values remain below average and seasonal
greenup is well underway. Will defer issuing any highlights for
winds as another couple of model runs should help clarify how far
south and east a wind advisory will be warranted.

Backing up to overnight, winds will return out of the south in wake
of surface high pressure vicinity Arklatex with surface pressures
falling along the lee of the Rockies in advance of the approaching
system. Decent diurnal cooling will allow temps to fall back into
the 40s with some upper 30s possible again northwest of Lubbock.

.LONG TERM...
Biggest changes to this forecast were to cool temps even further
Sat night and introduce improved prospects for a light freeze
on the Caprock with even some snow at times in our NW zones.

Beginning Thursday evening, an upper trough axis will emerge along
the spine of the Rockies and herald the development of an upper
low in NW flow. Models are in good harmony with this low
developing near the Four Corners by Fri evening, before tracking
roughly along I-40 in NM and the TX Panhandle through Sun A.M.
A weak lead impulse lifting out of the base of the trough Thu
night will nudge a dry cold front southward thru the region, but
with pressure falls organizing upstream ahead of the larger
trough/low on Fri, this boundary will stall and possibly retreat
during the day. Nonetheless, the windy gradient flow of Thu should
be dampened considerably with this boundary nearby, so winds on
Fri are of much less concern.

Friday night will see better dynamics emerge from W-E with the
arrival of an upper jet streak and height falls preceding the
upper low. The Gulf moisture contribution in our domain remains
low in this setup, however modest Pacific moisture with sustained
lift looks reasonable for some light precip amounts Fri night
through Sat night. Track of the low favors better PoPs in our
northern zones with mid-level dry slotting farther south likely
skunking larger windows of deeper saturation. Opted to shave PoPs
back more aggressively in our southern zones despite a few models
re-saturating the dry slot quite bullishly Sat night in the base
of the upper low. Of greater interest is the arrival of
unseasonably cold air during the morning with temperatures likely
falling during the day in areas. Temps were skewed closer to the
chilly raw model guidance which operates independently of the
climo-weighted and seasonably warmer MOS. All models show
reasonably cold profiles for some light snow potential mainly in
our NW zones late Sat in/near a deformation zone, with higher
probabilities taking aim north of I-40 NW of the mid-level low.
How much the aforementioned dry slotting interferes with
saturation in the dendritic growth layer will be critical in
deciding whether wintry precip develops or we`re left with only
shallow stratus.

Even with stiff northerly winds Sat night and early Sun, models
seem keen on a late freeze for portions of the Caprock given the
magnitude of cold advection. Trended min temps lower and much
closer to the National_Blend guidance. Otherwise, cold surface
ridging will depart on Sun ahead of relaxing cyclonic upper flow
on Monday, before yet another trough in NW flow sharpens upstream
of the region by Tue/Wed.

&&

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

$$

24/93


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