Severe Thunderstorm Warning 118, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
258 PM CDT Wed May 20 2020

.SHORT TERM (Tonight through Thursday Night)...
Latest visible satellite images are showing storms already firing up
across the northeast part of Mexico. This trend is expected to
continue for the rest of the afternoon into the evening hours. As
time progresses, an upper level shortwave over central Mexico is
forecast to push to the northeast and enhance storm development
along and ahead of the dryline that will ultimately send those
storms across parts of the Rio Grande this evening. The main weather
hazards for this evening are large hail and damaging wind gusts. One
thing for this forecast period is that HiRes models suggest a couple
of complexes of storms: one moving across the San Angelo area and
the other one over the Rio Grande. When it comes to medium range
solutions and for example, the NAM, keeps the area relatively quiet
with storms dissipating over Mexico this evening. Now, the GFS shows
a strong signal of storms and the ECMWF brings isolated convection
over Val Verde and ends it midnight. With that said, confidence is
low for these storms to hit any particular area along the Rio
Grande, however, the impacted areas could be dealing with large hail
and damaging wind gusts as mentioned earlier under this high cape
environment but low shear.

Thursday morning will start cloudy all over the area with clouds
breaking in the afternoon for partly cloudy skies for the period.
Highs will be cooler by at least 5 degrees across the area due cloud
coverage. Also, there is a slight to low end chances for showers and
thunderstorms in the afternoon for areas west of a Austin to Luling
to Karnes City line. Similar conditions continue on Thursday evening
as another short wave disturbance moves across the Southern Plains.

&&

.LONG TERM (Friday through Wednesday)...
Friday a strong upper level trough will begin moving out of the Great
Basin region and through the southwestern part of the country. A weak
shortwave trough embedded in the flow will move across Texas bringing
some low chance POPs for Friday and Friday night. The main trough
will continue to move to the east over the weekend and heights will
fall over Texas through this time frame. While this happens, the low
level flow will be from the southeast. With the warm, moist boundary
layer the height falls will bring chances for showers and
thunderstorms Saturday through Memorial Day. PW values will not be
excessive across our CWA and we don't expect heavy rain at any time
during this period. However, the slow movement of the upper system
will mean an extended period of showers and thunderstorms and the
accumulation over this period may eventually lead to flooding. Beyond
Monday, the upper trough will close off into a low and drift out over
the Gulf. Rain chances will continue as this feature moves slowly
away. As it move farther east POPs will decrease into the middle of
next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              73  90  72  89  72 /  10  10  20  30  10
Austin Bergstrom Intl Airport  73  89  71  90  72 /  10  10  20  30  10
New Braunfels Muni Airport     73  90  71  90  72 /  10  10  20  20  10
Burnet Muni Airport            71  88  69  87  70 /  20  20  30  20  10
Del Rio Intl Airport           74  91  72  95  72 /  30  20  20  20  20
Georgetown Muni Airport        71  89  71  88  72 /  10  10  20  20  10
Hondo Muni Airport             73  91  71  93  72 /  20  30  30  20  20
San Marcos Muni Airport        72  88  70  90  71 /  10  10  20  20  10
La Grange - Fayette Regional   74  90  73  91  74 /  10  -   10  20  10
San Antonio Intl Airport       74  91  72  90  72 /  20  20  20  30  20
Stinson Muni Airport           75  91  73  91  73 /  10  20  20  30  20

&&

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

Short-Term/Aviation...17
Long-Term...05
Decision Support...Runyen

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
316 AM CDT Wed May 20 2020

TXZ171>173-183>194-202>209-217>225-228-211200-
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-
316 AM CDT Wed May 20 2020

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

.DAY ONE...Today And Tonight.

Isolated storms will be possible late this afternoon and evening
across the Edwards Plateau and Rio Grande. Some of these storms
could be strong to marginally severe with hail and gusty winds the
main threats.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thunderstorm chances will be on the increase through the Memorial
Day holiday weekend. Some of these storms could be strong and
produce locally heavy rainfall mainly over the weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Austin/San Antonio TX
613 PM CDT Wed May 20 2020

TXZ183-184-202-217-210000-
Maverick TX-Kinney TX-Val Verde TX-Edwards TX-
613 PM CDT Wed May 20 2020

...SIGNIFICANT WEATHER ADVISORY FOR KINNEY...NORTHERN MAVERICK...
SOUTHWESTERN EDWARDS AND SOUTHEASTERN VAL VERDE COUNTIES UNTIL 700 PM
CDT...

At 612 PM CDT, Doppler radar was tracking a strong thunderstorm near
Box Canyon, or near Comstock, moving northeast at 20 mph. Additional
storms were across Mexico moving eastward towards Del Rio.

Nickel size hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Del Rio, Brackettville, Comstock, Spofford, Quemado, Lake View,
Amistad Acres, Darling, Laughlin AFB, Anacacho, Alamo Village, Carta
Valley, Cienegas Terrace, Amistad Village, Black Brush Point,
Seminole Canyon State Park, Amanda, Box Canyon, Val Verde Park and
Standart.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Lake Amistad, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.

&&

LAT...LON 3000 10093 2959 10034 2938 10019 2890 10020
      2890 10063 2909 10067 2917 10078 2924 10079
      2936 10100 2946 10106 2947 10115 2952 10118
      2952 10125 2962 10125 2963 10127 2958 10131
      2965 10130 2966 10135 2965 10136 2971 10138
TIME...MOT...LOC 2312Z 241DEG 17KT 2960 10111

AAT