Area Forecast Discussion
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FXUS64 KLUB 230144 AAA
AFDLUB

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
844 PM CDT Tue May 22 2018

.UPDATE...
Aside from a few small and brief showers across the northwestern
zones early this evening, convection has failed to materialize
across the CWA. With the loss of daytime heating, the window for
locally generated convection has come to a close. However, we will
still have to wait and see if the storms that originated over the
higher terrain of NM and southwest Texas can survive the journey
into the western South Plains later tonight. Most NWP suggests
that they should come close to the TX/NM line, though beyond that
(further east) it is far less certain. Regardless, timing the
closest radar echoes suggest that, should convection maintain
itself, it won`t cross the state line until around or after 04Z.
Hence, we have removed the storm mention over our CWA for the next
couple of hours before gradually expanding the slight chance to
chance mention of showers/storms to the western and eventually
central zones through the late evening and overnight hours.
Besides delaying the shower/storm mention this evening, no other
adjustments have been made the the grids attm.

&&

.PREV DISCUSSION... /issued 624 PM CDT Tue May 22 2018/

AVIATION...
Thunderstorm activity up near TXO at 00Z are expected to remain
clear of our terminal areas through much of the evening. There is
a risk of NM TSTM activity making a bee line for KLBB/KPVW later
this evening perhaps in the 06Z timeframe. Given the many
variables involved and a relatively low confidence that the
activity will make it all the way here, will elect to leave out
mention of TSRA ATTM. Otherwise VFR outside of convective
activity.

PREV DISCUSSION... /issued 240 PM CDT Tue May 22 2018/

DISCUSSION...
On convective initiation watch this afternoon as a modestly
unstable air mass is in place across the forecast with good low
level moisture lingering all the way back to the mountains of
central New Mexico. Isolated storms have developed on the
Sacramentos from south of Ruidoso to near Corona. We will likely
be looking a little closer to home for thunderstorm initiation
that will have a better chance of affecting the forecast area.
This better area will be in the vicinity of a surface trough that
is located roughly from Dalhart to west of Clovis to Roswell as
well as along any localized areas of low level confluence east of
the trough across the western counties of the forecast area. Hi-
res mesoscale models just about unanimously have some precip
across the western half of the area by early evening but vary in
timing, placement, and evolution. PoP`s in the 30-40 percent range
west of I-27 seems reasonable at this time fading to near 10
percent across the eastern column of counties. The convective
focus may shift a little further eastward both Wednesday and
Thursday as an upper low located over southern Nevada this
afternoon opens and moves northeastward across the Great Basin to
the lee of the northern Rockies potentially allowing for a bit of
veering of the low level flow. Entering the weekend models
continue the trend of building a narrow upper level ridge over the
southern and central High Plains with the forecast area underneath
the ridge axis through the weekend until Monday or Tuesday when
another upper low arrives over the Great Basin and
Colorado/Wyoming Rockies. This may effectively shut off
precipitation chances unless the mid level moisture evident on
water vapor imagery from Coahuila to Nebraska is able to be
trapped under the ridge and/or low level moisture remains
sufficiently in place across the forecast area. Models suggest the
former is a bit better possibility than the latter, and even then
the quality of the mid level moisture may be quite a bit less than
seen today. Thus, isolated thunder is not out of the question but
the signal is not strong enough to reintroduce precip chances
beyond Thursday. The other big question is how hot temperatures
will get this weekend. MOS values are now touching and even
exceeding 100 degrees for Saturday and Sunday while model blend
is a few degrees cooler. Again, this may depend on whether low
level moisture remains in place. Afternoon dew points in the 50s
will favor the 90s while near 40 or lower will favor the latter.
Will run with the slightly cooler blend at the moment but trends
may be beginning to favor the warmer MOS numbers.

&&

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

$$

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