Special Weather Statement, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
220 PM CDT Thu Jul 22 2021

.SHORT TERM (Tonight through Friday Night)...
The upper level low that has aided in development of afternoon
showers and thunderstorms continues to slowly drift westward across
West Texas. Per the GOES-16 Water Vapor images it has nudged closer
to Alpine, but continues to spin between Marathon and Fort Stockton
this afternoon. In the moist environment across South Central Texas
showers and thunderstorms have begun to develop. A broken line of
storms extends from west of Pearsall to north of Pleasanton to Falls
City this afternoon, with additional activity to the north and west
of that broken line. Showers and storms will continue to move north
through the afternoon hours. Morning Precipitable Water values were
1.56 at DRT and 2.25 at CRP and model soundings suggest some of the
juicy air observed this morning will help aid some locally heavy
downpours this afternoon, with PW values around 2 inches. Based on
morning CoCoRaHS observations some of the heavier showers Wednesday
afternoon produced localized totals of anywhere between 1.25 and
2.75 inches of rainfall leading to a handful of Flood Advisories
being issued. A similar setup with rainfall amounts and minor
flooding is possible this evening.

In general expect coverage of showers and thunderstorms to decrease
with the loss of daytime heating but the FV3 High Resolution model
along with basically all of the synoptic models (GFS/ECMWF/Canadian/
NAM) keep showers and thunderstorms across the Edwards Plateau and
Rio Grande Plains through the early morning hours before finally
pushing north and dissipating around sunrise Friday.

The ECMWF is quite bullish with another round of sea breeze activity
for Friday, while the other synoptic models and all of the HREF
members are less bullish or completely dry for tomorrow. Have gone
with a dry forecast for Friday area wide. The one place to watch
will be Val Verde County late in the day as some SdB thunderstorms
may try to work into the county thanks to the southwesterly upper
flow. The HREF models all dissipate this activity before it reaches
the border so have left mention out of this forecast package. The
upper ridge will begin to build across the area tomorrow as the low
continues to move to the northwest into New Mexico and away from
South Central Texas. With more sunshine and the ridge building in
afternoon highs tomorrow should be a few degrees warmer than they
are today.

&&

.LONG TERM (Saturday through Thursday)...
The subtropical ridge will dominate over Texas over the weekend and
early part of next week. The ridge will suppress any convection and
the weather will be dry across the entire CWA through Monday. High
pressure will also allow temperatures to climb up to near normal.
Dewpoint temperatures will remain fairly high with southeasterly low
level flow and heat indices will be 100-105 across most of the area.
Tuesday a weak tropical upper level trough will move toward the Texas
coast from the Gulf. This will bring a slight chance for showers and
thunderstorms to our extreme southeastern counties during the
afternoon. This weak system will continue to move toward the west and
low chances for convection will develop each afternoon Wednesday and
Thursday. The convection will move a little farther west reaching
I-35.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              75  94  75  96  75 /  20  -    0   0   0
Austin Bergstrom Intl Airport  75  93  74  96  74 /  20  -    0   0   0
New Braunfels Muni Airport     75  94  74  96  75 /  20  -    0   0   0
Burnet Muni Airport            74  92  74  94  73 /  10  -    0   0   0
Del Rio Intl Airport           77  98  77  99  77 /  20  -    0   0   0
Georgetown Muni Airport        75  94  74  95  73 /  20  10   0   0   0
Hondo Muni Airport             75  94  74  96  74 /  30  10   0   0   0
San Marcos Muni Airport        75  95  74  96  74 /  20  -    0   0   0
La Grange - Fayette Regional   77  95  76  96  76 /  20  10   0   0   0
San Antonio Intl Airport       76  92  75  95  75 /  30  -    0   0   0
Stinson Muni Airport           77  95  76  97  76 /  30  -    0   0   0

&&

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

Short-Term/Aviation...Treadway
Long-Term...05
Decision Support...Oaks

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
303 AM CDT Thu Jul 22 2021

TXZ171>173-183>194-202>209-217>225-228-230815-
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-
303 AM CDT Thu Jul 22 2021

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

.DAY ONE...Today And Tonight.

Scattered showers and thunderstorms are expected. Locally heavy
rains are possible and may cause some urban and small stream type
flooding. Gusty winds are also possible.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Austin/San Antonio TX
320 PM CDT Thu Jul 22 2021

TXZ206-207-223-222045-
Guadalupe TX-Comal TX-Gonzales TX-
320 PM CDT Thu Jul 22 2021

...SIGNIFICANT WEATHER ADVISORY FOR GUADALUPE...NORTHWESTERN GONZALES
AND SOUTHEASTERN COMAL COUNTIES UNTIL 345 PM CDT...

At 320 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Schertz to near Seguin. Movement was north at
20 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
New Braunfels, Schertz, Seguin, Cibolo, Selma, Luling, Randolph AFB,
Canyon Lake, Garden Ridge, McQueeney, Marion, Kingsbury, Santa Clara,
New Berlin, Staples, Zuehl, Geronimo, Zorn, Fentress and Startzville.

LAT...LON 2933 9783 2935 9786 2938 9784 2937 9811
      2948 9812 2949 9819 2955 9823 2955 9826
      2954 9827 2961 9833 2985 9834 2983 9802
      2976 9800 2982 9793 2981 9784 2971 9773
      2969 9774 2964 9762
TIME...MOT...LOC 2020Z 182DEG 17KT 2958 9826 2955 9800

RUNYEN