Area Forecast Discussion
Issued by NWS San Angelo, TX

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000
FXUS64 KSJT 192332
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
632 PM CDT SAT APR 19 2014


.AVIATION...
/00Z TAFS/

Line of showers/thunderstorms west of FT Stockton at 23Z should
weaken as it moves off the mountains and with loss of daytime
heating. It is possible a few storms may survive to arrive at KSJT
and KABI after 3Z. With potential low, however, kept thunderstorm
mention out of TAFS.

MVFR stratus likely towards morning as low level moisture continues
to flow up from the Gulf. Scattered morning showers are near KABI as
western upper trough approaches the region. Showers should be more
isolated farther south. Isolated thunderstorms possible late morning
and afternoon across West Central Texas, but KABI will have the best
chance and added VCTS in its TAF.

04


&&

.PREV DISCUSSION... /ISSUED 250 PM CDT SAT APR 19 2014/
.SHORT TERM...
(Tonight and Sunday)

The main concern for tonight is the chance for showers and
thunderstorms sometime after 10 PM CDT across the western half of
the CWA...and then the chance for severe storms tomorrow in the same
area but including much of the Big Country.  Latest radar loop,
shows a small area of shower development across Crockett County that
was moving northeast but weakening with time.

A deep upper level trough of low pressure over Mexico was
approaching West Central Texas this afternoon as low level gulf
moisture continues to deepen across the region.  Water vapor loop
was also showing a speed max over Mexico approaching the Big Bend.
As upper level divergence increases in advance of this feature, the
HRRR and the Texas Tech 4KM WRF showed the development of a cluster
of showers and thunderstorms across West Texas tonight that will
move east and northeast into West Central Texas shortly after 03Z or
10 PM CDT.  However, these high resolution short term models show
the MCS weakening as they move into a more stable airmass across
West Central Texas tonight.  However, can`t rule out an isolated
strong to severe storm developing tonight.  Have raised PoPs across
the western half of the area to 50 percent.

Models do show the airmass across West Central Texas becoming
increasingly unstable east of the dry line by tomorrow afternoon as
most unstable CAPE Values range from 1000 to 1600 J/KG with 0 to 6KM
bulk shear values ranging from 35 to 50 knots across the region.
For this reason...the Storm Prediction Center has placed the western
half of the CWA in a slight risk for severe storms.  The main
impacts will be large hail and damaging winds.

26

.LONG TERM...
(Sunday Night through Saturday)

Sunday evening, convection will likely be ongoing across parts of
West Central Texas, especially the Big Country. A dryline will be
located across West Texas, with a moderately unstable environment
across much of our area. Scattered showers and thunderstorms are
forecast to develop across the western portions of the area during
the afternoon, with some convection lingering into the evening
hours. The best chance during the evening will be across the Big
Country. A few strong to severe thunderstorms will be possible, with
large hail and damaging winds being the main threats. On Monday
morning, a weak cold front will move into the Big Country, then make
slow progress toward the Interstate 10 corridor by evening. Ahead of
this feature, compressional heating will lead to unseasonably warm
temperatures, with highs generally in the mid to upper 80s. Isolated
to scattered showers will be possible during the afternoon, as the
atmosphere becomes increasingly unstable. I expect the best chance
to be generally southeast of an Abilene, to San Angelo, to Ozona
line. A few of these storms could become strong to severe,
especially across the southeast counties.

Upper level ridging on Tuesday will result in a continuation of the
above normal temperatures, with highs generally in the mid to upper
80s. The next upper level trough will come ashore the Northwest
Pacific Tuesday, then approach the Plains late Wednesday. As this
feature approaches, it will aid in the development of dryline
showers and thunderstorms, first across our western counties late
Wednesday afternoon, then advancing east into the rest of the area
during the evening hours. Given the uncertainty this far out, I have
continued with only slight chance PoPs, but these may need to be
bumped up on future shifts. The above normal temperatures will
continue through the end of the work week, with highs generally in
the upper 80s to lower 90s, and overnight lows in the 60s. Models
are indicating the approach of another upper level trough next
weekend, which could bring another chance of showers and
thunderstorms.

Daniels

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene  59  78  62  84  59 /  40  40  30  10  10
San Angelo  59  79  62  88  59 /  50  40  20  20  10
Junction  60  77  63  85  60 /  30  30  20  30  20

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

26/Daniels






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