Area Forecast Discussion
Issued by NWS San Angelo, TX

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000
FXUS64 KSJT 270407
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
1107 PM CDT Tue May 26 2015

.AVIATION...
/06Z TAFS/
MVFR stratus will move north across the area through the early
morning hours...first arriving at the southern terminals around
08Z and at the KABI terminal by 11Z, with IFR conditions at KSOA.
The stratus will burn off into scattered cu field by 18Z,
resulting in VFR.

&&

.PREV DISCUSSION... /ISSUED 614 PM CDT Tue May 26 2015/

AVIATION...
/00Z TAFS/

Severe storms 30 miles west of San Angelo, moving slowly east, may
affect KSJT between 1-3Z. While the KSJT terminal has -tsra, there
is the potential for strong damaging winds and large hail if storm
strength persists. Otherwise MVFR stratus moves in after midnight
from southeast to northwest, with IFR stratus likely at KSOA.
Stratus lifts to VFR 15 to 18Z.

PREV DISCUSSION... /ISSUED 322 PM CDT Tue May 26 2015/

SHORT TERM...
(Tonight and Wednesday)

Convection likely once again across West Central Texas, with
scattered thunderstorms developing. High CAPE, relatively modest
shear day suggests very large hail as the main threat. Can`t rule
out an isolated tornado, especially as the low level jet ramps up
later this evening. Coverage is a big question, but once a few
storms develop they may be able to produce outflow for additional
development. All of this is conditional of course on getting the
first few storms to develop.

Given the moist air mass in place, and the low level jet of 30+
knots, if storms develop they may linger well past sunset. Once
they eventually dissipate, low clouds will return to the area.
These will continue into the morning before finally breaking up.
Chances for convection on Wednesday will be somewhat conditional
on what happens today. Dryline will be well west and there will be
weak ridging in place aloft for much of the afternoon. A weak
shortwave may approach West Texas for the Wednesday Night time
frame, but getting storms to develop before 00Z may well depend on
lingering outflow boundaries from tonights storms. Will include a
mention of isolated PoPs areawide, with the assumption that later
forecasts will need to define the area better.

07

LONG TERM...
(Wednesday night through next Tuesday)

By Wednesday night, the next strong upper level trough will be
starting to make its move toward west Texas. The NAM shows the
convection occurring earlier, more during Thursday afternoon and
evening as opposed to Thursday night. This is a break from the
trend that the GFS and ECMWF have established with most of the
convection expected Thursday night as the main upper level trough
axis sweeps through Texas, so have kept likely PoPs going through
the overnight hours Thursday night. However, this doesn`t preclude
the possibility of some scattered afternoon thunderstorms
developing Thursday ahead of the main trough in a very unstable
environment. Although models aren`t showing just fantastic shear,
MLCAPES Thursday afternoon and evening will be roughly 1500 J/kg
or greater, and thus severe weather will continue to be a concern
with large hail and damaging winds being the main hazards, in
addition to heavy rainfall and localized flooding.

Expect a drier day for Friday as we will be in between systems,
relatively speaking.

A cold front is still expected to slowly move south into Texas
Friday night into Saturday that could result in additional showers
and thunderstorms from Saturday afternoon into Sunday. However, the
any rain chances will be at least somewhat dependent on the
position of the front, and there is still a lot of uncertainty
with respect to how far south that front will make it, so have
kept PoP chances generally in the low end chance category from
Saturday through Sunday.

Weak northwest flow sets up by Monday with ridging over the
southern Rockies, as an upper level low moves southeast through
the Mississippi Valley. The ridge is expected to expand to the
east into our CWA during the first half of next week, so have kept
the inherited downward trend in PoPs from Monday into the middle
of next week.

20

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene  70  88  68  84  66 /  30  20  20  40  60
San Angelo  70  91  68  83  67 /  20  20  20  40  60
Junction  67  86  70  84  69 /  20  20  20  40  50

&&

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

$$

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