Severe Thunderstorm Warning 67, NWS Austin/San Antonio, TX

264 
WWUS54 KEWX 201850
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
150 PM CDT SUN MAY 20 2018

TXC271-463-201930-
/O.CON.KEWX.SV.W.0067.000000T0000Z-180520T1930Z/
Kinney TX-Uvalde TX-
150 PM CDT SUN MAY 20 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM CDT
FOR EASTERN KINNEY AND WEST CENTRAL UVALDE COUNTIES...

At 149 PM CDT, a severe thunderstorm was located 9 miles east of 
Brackettville, moving southeast at 25 mph.

HAZARD...60 mph wind gusts and nickel size hail. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to roofs, siding, and trees. 

Locations impacted include...
Cline and Turkey Mountain. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 2938 10041 2952 10030 2940 9996 2910 10024
TIME...MOT...LOC 1849Z 311DEG 31KT 2931 10026 

HAIL...0.88IN
WIND...60MPH
 
$$

PLATT

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
113 PM CDT Sun May 20 2018

.UPDATE...
Please see the 18Z aviation forecast discussion below.

&&

.AVIATION...
The main concern over the next 6 hours will be scattered to numerous
showers and thunderstorms across the region. Based on radar trends
and hi-res model output, we have gone with TEMPO groups for our TAF
sites through 22Z at DRT and at least 00Z. Based on convective
trends, we may have to extend the mention of TSRA beyond 00Z in later
forecasts. Once convection ends, we should see a return of low clouds
and MVFR cigs for the overnight and morning hours on Monday.

&&

.PREV DISCUSSION... /ISSUED 1246 PM CDT Sun May 20 2018/

EARLY AFTERNOON UPDATE...
Increased PoPs and QPF for the next 6 hours across the area as the
outflow boundary continues to provide lifting in the uncapped and
unstable environment across the region. As this boundary continues to
move southward, it will begin interacting with an increasing PWAT
environment, as high as 2" according to the RAP mesoanalysis west of
the I-35 corridor. Additionally, strong moisture flux convergence
along the boundary should maintain development of new cells
throughout the rest of the afternoon.

WPC has increased their excessive rainfall risk to "slight" for the
majority of the CWA and suggesting 3-5 inches of rainfall as a
possibility over the next several hours. As we have already seen
1-2"/hr rain rates with this activity thus far and judging from
latest CAMs, believe this is a fair estimation with the upper end 5
inch mark being the more isolated value.

Thankfully, flash flood guidance values are very high for our area
due to lack of extended rain over the last month. The most
susceptible locations for possible flash flooding will be the major
metro areas due to urban effects but otherwise guidance suggests
hourly rain rates of over 2.5"/hr needed and over 5 inches for most
areas during the 6 hour time frame. Thus, do not feel that there is
a need for a Flash Flood Watch at this time, however cannot rule out
the need for a FFW or two over the course of the afternoon.

Will have another update during the regular AFD afternoon issuance
with more info from the 12Z model suite.

PREV DISCUSSION... /ISSUED 749 AM CDT Sun May 20 2018/

MORNING UPDATE...
Per latest radar trends and short term model depictions, increased
PoPs through 18Z for the Hill Country and Austin areas as well as the
Edwards Plateau. Outflow boundary is progressing southward faster
than models anticipated and will be arriving in the northern CWA in
the next hour or so which should increase shower and isolated storm
coverage across the northern half of the CWA throughout the morning.

PREV DISCUSSION... /ISSUED 640 AM CDT Sun May 20 2018/

AVIATION...
MVFR ceilings will settle over the region within the next hour or so.
Clouds should lift late this morning or early afternoon. Another
round of showers and thunderstorms is expected this afternoon.
Convection will lower visibility to MVFR. There is a chance showers
and thunderstorms continue into the evening, but probability is too
low to include anything in the TAFs. Ceilings will lower again
overnight tonight into Monday.

PREV DISCUSSION... /ISSUED 333 AM CDT Sun May 20 2018/

SHORT TERM (Today through Monday)...
A mid level impulse has generated showers and isolated thunderstorms
that has moved east of I-35. This activity exits to our east by
sunrise. An outflow boundary is surging south across northern and
western Texas and will move into our area later this morning as a
series of mid level impulses move across. Upward forcing due to the
boundary and impulses, as well as, heating allow showers and
thunderstorms to develop as the day progresses. This activity will
generate additional boundaries, as well as, the impulses aloft to
maintain the showers and thunderstorms through Monday as a moist
airmass lingers. With time, most activity shifts to the Rio Grande
Plains where showers and thunderstorms coming off the Serranias del
Burro of Mexico and the Big Bend and Davis Mountains of southwestern
Texas could form into clusters and move across that area. High CAPE
noted on forecast soundings indicate the possibility of strong to
severe storms with large hail and damaging winds the main threats
mainly during the afternoon into evening hours today and again on
Monday. A few storms could be slower moving and produce locally heavy
downpours. Daytime temperatures will be cooler due to the clouds and
rain.

LONG TERM (Monday Night through Saturday)...
A mid and upper level ridge begins to build over our area on Tuesday
with increasing convective inhibition due to warming mid level
temperatures. Some deeper moisture lingers to allow isolated showers
and thunderstorms near the Coastal Plains due to the seabreeze and
over the lower Pecos Valley of Val Verde due to proximity to activity
coming off the higher terrain of Mexico and southwestern Texas. For
Wednesday through Saturday, the ridging aloft keeps convection out of
the forecast. However, cannot rule out very isolated showers and
thunderstorms over those two areas. Temperatures will warm back to
well above normal mid to late week into next weekend. The next
chance of rain is next Saturday night when a front moves through our
area.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              84  70  88  70  90 / 100  30  30  10  10
Austin Bergstrom Intl Airport  85  70  89  69  90 / 100  30  30  10  20
New Braunfels Muni Airport     84  70  88  69  89 /  90  30  30  10  10
Burnet Muni Airport            79  67  86  67  88 / 100  30  30  10  10
Del Rio Intl Airport           85  71  88  71  89 /  90  40  50  20  10
Georgetown Muni Airport        83  68  88  68  89 / 100  30  30  10  10
Hondo Muni Airport             85  70  88  69  90 /  80  30  30  10  10
San Marcos Muni Airport        85  69  88  69  90 /  90  30  30  10  10
La Grange - Fayette Regional   86  71  89  71  90 /  80  30  30  10  20
San Antonio Intl Airport       85  71  88  71  89 /  90  30  30  10  10
Stinson Muni Airport           86  72  88  71  90 /  80  30  30  10  10

&&

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

Mesoscale/Aviation...24
Synoptic/Grids...TB3
Public Service/Data Collection...YB

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
1231 PM CDT Sun May 20 2018

TXZ171>173-183>194-202>209-217>225-228-211745-
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-
1231 PM CDT Sun May 20 2018

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

.DAY ONE...This Afternoon And Tonight.

Scattered showers and thunderstorms will continue to develop
throughout the rest of the afternoon and through the evening hours
producing locally heavy rainfall and potentially some localized
flash flooding. Additionally some stronger storms could produce
small hail and strong straight line winds.

Hourly rainfall rates between 1 to 2 inches are possible with the
strongest downpours. This could result in rainfall amounts of two
to four inches with locally higher amounts over 5 inches.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a low chance for strong to severe thunderstorms on
Monday. The main concerns will be damaging winds and large hail.
Otherwise, no hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
909 AM CDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0841 AM     TORNADO          3 NE LEANDER            30.60N 97.82W
05/20/2018                   WILLIAMSON         TX   AMATEUR RADIO

            AMATEUR RADIO OPERATOR REPORTS SHINGLE
            DAMAGE TO A HOME, AN ABOVE GROUND POOL
            DEMOLISHED, AND A TREE DOWN AT 3336 HERO WAY
            IN LEANDER, TX.

&&

TB3

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
918 AM CDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0843 AM     TORNADO          5 E LIBERTY HILL        30.66N 97.84W
05/20/2018                   WILLIAMSON         TX   EMERGENCY MNGR

            WILLIAMSON COUNTY EMC REPORTS TREE DAMAGE AT
            THE SANTA RITA RANCH NORTH SUBDIVISION OFF
            OF RONALD REAGAN BLVD.

&&

TB3

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
921 AM CDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0841 AM     TORNADO          3 NE LEANDER            30.59N 97.82W
05/20/2018                   WILLIAMSON         TX   TRAINED SPOTTER

            REPORT OF ROOF DAMAGE TO THREE STRUCTURES AT
            3450 HERO WAY IN LEANDER, TX.

&&

TB3

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1137 AM CDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1130 AM     HAIL             3 SE CYPRESS MILL       30.34N 98.22W
05/20/2018  E0.25 INCH       BLANCO             TX   TRAINED SPOTTER

&&

Special Weather Statement
National Weather Service Austin/San Antonio TX
1220 PM CDT SUN MAY 20 2018

TXZ183-184-202-201815-
Kinney TX-Val Verde TX-Edwards TX-
1220 PM CDT SUN MAY 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN KINNEY...
SOUTHWESTERN EDWARDS AND EAST CENTRAL VAL VERDE COUNTIES UNTIL 115 PM
CDT...

At 1220 PM CDT, Doppler radar was tracking a strong thunderstorm near
Carta Valley, or 9 miles southeast of Loma Alta, moving southeast at
25 mph.

Dime size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Carta Valley and U.S. Highway 377.

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.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 2976 10086 2997 10071 2983 10028 2949 10069
TIME...MOT...LOC 1720Z 309DEG 22KT 2984 10065

PLATT

Special Weather Statement
National Weather Service Austin/San Antonio TX
103 PM CDT SUN MAY 20 2018

TXZ184-202-201845-
Kinney TX-Edwards TX-
103 PM CDT SUN MAY 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN KINNEY AND SOUTH
CENTRAL EDWARDS COUNTIES UNTIL 145 PM CDT...

At 102 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Alamo Village, or 16 miles north of Brackettville,
moving southeast at 30 mph.

Dime size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Brackettville, Alamo Village, Fort Clark Springs and Kickapoo Cavern
State Park.

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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 2954 10063 2979 10033 2966 10009 2921 10045
TIME...MOT...LOC 1802Z 309DEG 27KT 2955 10044

PLATT