Special Weather Statement, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
237 PM CDT Tue Sep 28 2021

.SHORT TERM (Tonight through Wednesday Night)...
Once morning low clouds eroded, temperatures have quickly warmed
into the low to mid 90s under partly cloudy skies with light winds
from out of the south. Few isolated showers have got going at times
but expect for some additional development of activity during the
afternoon. However, the main focus late this afternoon and into the
evening should be across portions of the Hill Country and towards
the Rio Grande. Anticipate thunderstorms to develop and organize
into a line or complex of activity that advances eastward to east-
southeastward into and through the overnight hours. The convective
allowing model guidance agree on general formation of this organized
convection but do not completely agree regarding the placement and
forward propagation of this activity. Nonetheless, expect locally
heavy rainfall with these thunderstorms as the PWATs climb to 1.75+
inches within a deep warm cloud layer. While it is difficult to
pinpoint locations, there is the potential for 1 to 3 inches for
some areas with locally higher amounts. Even though the rain will be
mainly beneficial given the dry antecedent conditions, any heavier
rain rates and totals may still be enough to overcome and result in
some minor flooding concerns. Additionally, convective parameters
with MLCAPE around 2500 J/kg and weak but sufficient bulk deep layer
shear of around 25 to 30 knots across the region could yield to
isolated severe storms with possible stronger wind gusts and large
hail.

Activity looks to diminish in coverage during the day on Wednesday
once the lift weakens a bit as the vort max driving the overnight
activity pushes to the east. Additionally, the atmosphere needs to
take some time to recover after the overnight convection. However
with higher moisture levels still in place, I'll still keep slight
chance to chance PoPs in the forecast. Some models, including the
GFS and CAM guidance, indicate that another vort max could make
progress into the region from the southwest during Wednesday night
into early Thursday. This results in return of some higher PoPs,
especially to the south and west of San Antonio.

Beyond the rain/convective forecast, expect for overnight lows in
the mid to upper 60s across the Hill Country and low to mid 70s
elsewhere with plenty of cloud cover. Highs on Wednesday could be
rather tricky depending on how exactly the convection overnight
evolves, but I'll go with values that top out in the mid to upper
80s and low 90s this forecast cycle.

&&

.LONG TERM (Thursday through Tuesday)...
The low level flow will remain from the south to southeast to start
the long term period. This will bring another surge of moist air from
the Gulf. Model forecasts show PW 1.75 to 2.00 inches over most of
our CWA by Thursday night. At the same time another mid to upper
level trough will move slowly through the southwestern US. A series
of shortwave troughs will move through the pattern and combine with
the low level moisture to generate showers and thunderstorms.
Widespread showers will be likely Thursday and Friday. The best
chances look to be Thursday night and daytime Friday. With the high
PW forecast, locally heavy rain will be possible during this time
frame with Friday afternoon looking a little more favorable for heavy
rain. Friday night and Saturday the trough axis will swing across our
CWA and rain chances will continue. As the trough moves through, the
PW values are forecast to decrease and thus POPs and QPF are a little
lower. A cold front will move through North Texas Sunday and then our
CWA Monday. This will bring another chance for rain to most of the
area. Behind the front Tuesday isolated showers will linger across
the south and west.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              72  89  72  89  71 /  70  40  30  80  70
Austin Bergstrom Intl Airport  70  88  71  88  70 /  70  40  30  80  70
New Braunfels Muni Airport     71  89  72  89  70 /  70  40  40  80  70
Burnet Muni Airport            69  87  70  87  68 /  70  20  30  70  70
Del Rio Intl Airport           72  93  73  91  70 /  50  20  30  60  70
Georgetown Muni Airport        71  87  71  88  70 /  70  30  30  80  70
Hondo Muni Airport             71  91  71  88  69 /  70  30  50  70  70
San Marcos Muni Airport        71  88  71  89  69 /  70  40  30  80  70
La Grange - Fayette Regional   73  88  73  89  72 /  70  50  30  80  60
San Antonio Intl Airport       72  89  73  87  71 /  70  40  50  80  70
Stinson Muni Airport           74  91  74  89  73 /  70  40  50  80  70

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

Short-Term/Aviation...Brady
Long-Term...05
Decision Support...Hampshire

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
516 AM CDT Tue Sep 28 2021

TXZ171>173-183>194-202>209-217>225-228-291030-
Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera-
Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde-
Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala-
Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit-
516 AM CDT Tue Sep 28 2021

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Today And Tonight.

There is a marginal risk severe thunderstorms from late this
afternoon into late tonight. Localized strong wind gusts and
marginal large hail are possible, mainly over areas west of the
I-35 corridor. By late tonight there is a potential for some
areas to see heavy rainfall amounts of 1 to 3 inches with
isolated higher amounts. Dry soil conditions across the region
should prevent significant areas of run-off through tonight, but
isolated areas of flooding will still be possible. Heaviest
rainfall amounts through tonight are forecast to be near the
Highway 281 and I-35 Corridors.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Periods of showers and thunderstorms are expected each day
Wednesday through Sunday. Isolated heavy rainfall amounts up to 3
inches are possible each day, mainly Wednesday through Saturday.
With each successive round of rainfall, the potential for
flooding should increase as soils become more saturated and area
creeks and streams become swollen.

.SPOTTER INFORMATION STATEMENT...

Formal activation of storm spotters is not expected, but timely
reports of severe winds, hail, and flooding are appreciated.

Special Weather Statement
National Weather Service Austin/San Antonio TX
453 PM CDT Tue Sep 28 2021

TXZ183-202-282215-
Kinney TX-Val Verde TX-
453 PM CDT Tue Sep 28 2021

...A strong thunderstorm will impact portions of southwestern Kinney
and southeastern Val Verde Counties through 515 PM CDT...

At 452 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles south of Laughlin AFB, or 12 miles southeast of Del Rio, moving
northeast at 25 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Del Rio, Standart, Amanda, Laughlin AFB and Escondido Estates.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2944 10076 2926 10049 2913 10073 2918 10077
      2920 10077 2922 10078 2923 10080 2924 10079
      2926 10081 2926 10084 2928 10086
TIME...MOT...LOC 2152Z 226DEG 20KT 2923 10076

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service Austin/San Antonio TX
513 PM CDT Tue Sep 28 2021

TXZ202-217-282300-
Maverick TX-Kinney TX-
513 PM CDT Tue Sep 28 2021

...A strong thunderstorm will impact portions of south central Kinney
and northern Maverick Counties through 600 PM CDT...

At 512 PM CDT, Doppler radar was tracking a strong thunderstorm over
Quemado, moving northeast at 30 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Spofford, Quemado, Paloma, Radar Base, Normandy, Darling, Laughlin
AFB Aux Field, U.S. Highway 277 and Farm to Market Road 1908.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2885 10057 2888 10060 2889 10059 2891 10062
      2890 10063 2892 10064 2892 10063 2894 10065
      2900 10065 2908 10067 2921 10035 2893 10015
      2883 10057
TIME...MOT...LOC 2212Z 239DEG 29KT 2894 10065

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

PLATT