Area Forecast Discussion
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FXUS64 KLUB 252338
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
638 PM CDT Sat Mar 25 2017

.AVIATION...
The main aviation concern will be low-level wind shear early
Sunday morning. A S-SW low-level jet will increase to around 40
kts at 800 to 1000 ft AGL on the Caprock after midnight. Then, as
the low-level jet wanes after sunrise, surface winds will pick up
during the morning as they turn westerly, then spread into the
Rolling Plains early afternoon. Sustained wind speeds at KLBB and
KPVW are expected to be around 20 to 25 kts. Winds will begin to
decrease at the end of the TAF period.

&&

.PREV DISCUSSION... /issued 311 PM CDT Sat Mar 25 2017/

SHORT TERM...
Surface pressure ridge was making steady progress off the Caprock
this afternoon ahead of light SW winds. Progressive movement of this
ridge was in sync with an upper ridge over eastern NM. As the upper
ridge passes east this evening, high clouds will exert more presence
ahead of a well-defined trough currently exiting the lower Great
Basin. Approach of this impulse and a surface low in the northern TX
Panhandle will spur a northward return of shallow Gulf moisture just
east of our Rolling Plains` counties toward daybreak. However, with
westerly flow only growing deeper in the base of the trough, our
domain will remain west of an emerging dryline by midday and have to
contend with very breezy west winds of 20 to 30 mph.

Model dewpoints in the dry sector tomorrow still appear a bit too
moist, so have undercut these accordingly which lends more support
to raising max temps and wind speeds given deeper mixing potential.
All this fits with the inherited Fire Wx Watch which encapsulates
the area of 3-hours of critical conditions. Greening of fuels is
restricted to mainly short grasses with enough dormant fuel stands
still capable of fire spread. As the trough axis exits the region by
sunset, a dry cold front will motor south ahead of north winds of 15-
20 mph. This wind shift will be of primary concern for any wildfire
activity.

LONG TERM...
Winds will be on the decline on Sunday evening as upper level
ridging begins to move into the region.  However, by Monday evening,
the next system should make it to about 115W then cutting off as it
passes Arizona.  The remnants of this system should be moving across
TX by Thursday morning. Into Friday, the next system comes ashore
the Pac NW coast and dives toward the four corners. At this point
the ECM/GFS start to diverge with the GFS, in an unusual
transition season move, drags the passage out until late Sunday.

A cold front will bring slightly cooler air into the region for
early Monday though return will be back in business by sundown. Some
streamer showers are then expected Tuesday morning as strong moist
advection sets up ahead of the approaching upper low.  The setup
continues to point toward deep convection by Tuesday afternoon.
Given the dynamical setup, some severe storms will be possible
though the shear vs. instability will probably keep the severe risk
on the lower end.  Tuesday night into Wednesday has a number of
models depicting heavy rain potential to our east and northeast. The
tendency appears to have rain mainly persisting in the east by
Wednesday morning though, given what often occurs, the precipitation
will be east of our CWFA.  However, into Wednesday, there continues
to be some indication that a cold front will bring with it some post
frontal light precipitation.  Overall, the models seem to hold on to
the precip much too long.  Will therefore nudge pops downward on Wed
particularly in the S/SW where the influence of the dry slot should
be greatest.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Sunday afternoon through Sunday evening
for TXZ027>031-033>037-039>043.

&&

$$

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