Severe Thunderstorm Warning 182, NWS San Angelo, TX

Area Forecast Discussion
National Weather Service SAN ANGELO TX
701 PM CDT SUN MAY 22 2016

.AVIATION...
/00Z TAFS/

Convection has fired west of the area late this afternoon and
early evening along and ahead of the dryline. Some of this
activity may reach the KSOA, KSJT and possibly the KABI terminals
this evening before weakening. Since activity is rather sparse,
will keep any mention of TS out of the forecast at this time and
continue to monitor trends this evening. Otherwise, MVFR ceilings
are expected across the terminals overnight into Monday Morning,
as stratus develops once again. Ceilings are expected to
lift/scatter out to VFR by late morning.

&&

.PREV DISCUSSION... /issued 342 PM CDT SUN MAY 22 2016/

SHORT TERM...
(Tonight and Monday)

An upper ridge extends from Texas north-northeast into the upper
Mississippi Valley, with the ridge axis shifting slowly east of
our area this afternoon. The dryline is mixing east across the far
western part of Texas, and a few thunderstorms are developing
across parts of the Panhandle to near Childress. The airmass is
very unstable ahead of the dryline and across our area, where
MLCAPE values have increased to 3000-4000 J/KG. The cap is eroding
with partly cloudy skies and surface heating across much of our
area.

Despite lack of large scale forcing for ascent, intense scattered
thunderstorm development is expected along and ahead of the
dryline through late this afternoon and early evening. Steering
flow may allow a few of these to move into the western part of our
area during the evening and early tonight. Elsewhere across our
area, the models continue to offer different solutions on where
storms may develop and track. We are carrying 30-40 PoPs this
afternoon and into tonight. With strong instability and effective
bulk shear 35- 40kt, our area has an accompanying severe weather
risk with the threats including very large hail, damaging winds,
and an isolated tornado. With a rather moist airmass across our
area and precipitable water values between 1.2 and 1.6 inches,
locally heavy rainfall is also possible.

Development of a low-level jet could help to sustain convection
into the night, but rain chances should drop off considerably
after Midnight. Warm and humid conditions are expected with
overnight lows around 70 degrees.

The overall setup on Monday looks similar to today with southwest
flow over our area, but the upper ridge axis will be a little
farther east. The dryline may mix a little farther east into West
Texas Monday afternoon, and the airmass out ahead of it will be
very unstable and moist. We are carrying 20-30 PoPs on Monday,
primarily for the afternoon. The slightly higher (30%) PoPs are
across the northwest part of our area, which will be a little
closer to the dryline. With a similar setup with instability and
vertical shear, the severe weather threats Monday afternoon and
early evening will be similar to those of this afternoon. The SPC
Day 2 Convective Outlook has Slight Risk for much of our area.

19

LONG TERM...
(Monday night through next Sunday)

No significant changes were made in terms of reasoning for the
long term from the previous discussion/forecast. We will continue
to be under southwest flow most of the upcoming work week. The
dryline will move east during the day, retreat during the
overnight hours. With the dryline making it near/into our western
counties each day, and having plenty of instability to work with
due to warm temperatures and plentiful Gulf of Mexico moisture,
isolated to scattered thunderstorms will be possible nearly every
afternoon near/along our western CWA border. As was mentioned in
the previous discussion, pinning down which day has a better
chance at this time is problematic at best, due to the inability
of time any shortwave help moving across the area in southwest
flow aloft. An upper level low is expected to lift northeast into
the Central Plains region late in the week, and this should
represent a more organized broad scale chance for showers and
thunderstorms from Thursday into Friday. We return to weak
southwest flow aloft for the weekend.

20

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene 	 70  86  70  89 /  40  20  20  20
San Angelo 	 70  87  69  90 /  30  20  20  20
Junction 	 68  85  70  88 /  30  20  20  10

&&

.SJT Watches/Warnings/Advisories...
None.
&&

99/99/24

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
325 PM CDT SUN MAY 22 2016

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-
140-154-155-168>170-232030-
FISHER-NOLAN-STERLING-COKE-RUNNELS-IRION-TOM GREEN-CONCHO-
CROCKETT-SCHLEICHER-SUTTON-HASKELL-THROCKMORTON-JONES-SHACKELFORD-
TAYLOR-CALLAHAN-COLEMAN-BROWN-MCCULLOCH-SAN SABA-MENARD-KIMBLE-
MASON-
325 PM CDT SUN MAY 22 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

WIDELY SCATTERED THUNDERSTORMS COULD MOVE INTO OR DEVELOP IN
WEST CENTRAL TEXAS LATE THIS AFTERNOON THROUGH EARLY TONIGHT.
THE SEVERE WEATHER THREATS INCLUDE VERY LARGE HAIL...DAMAGING
WINDS AND ISOLATED TORNADOES...ALONG WITH DEADLY LIGHTNING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SCATTERED SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF
WEST CENTRAL TEXAS MONDAY AFTERNOON AND EVENING. THE PRIMARY
HAZARDS WILL BE VERY LARGE HAIL...DAMAGING WINDS...DEADLY
LIGHTNING AND AN ISOLATED TORNADO. SCATTERED THUNDERSTORMS WILL
BE POSSIBLE EACH DAY TUESDAY THROUGH FRIDAY. SOME STORMS COULD
BECOME SEVERE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED THIS AFTERNOON AND
EVENING...AND AGAIN MONDAY AFTERNOON AND EVENING.