Flash Flood Warning 10, NWS Austin/San Antonio, TX

423 
WGUS74 KEWX 210102
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
802 PM CDT Mon Apr 20 2026

TXC029-091-187-210200-
/O.CON.KEWX.FF.W.0010.000000T0000Z-260421T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Comal TX-Guadalupe TX-
802 PM CDT Mon Apr 20 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING 
FOR NORTHEASTERN BEXAR, SOUTHEASTERN COMAL AND WEST CENTRAL 
GUADALUPE COUNTIES...

At 802 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the western part of Bexar County. This area of the 
county did not get a lot of rain earlier, however, a quick 0.25 to 
0.5 inch and up to an inch of rainfall is possible a line of storms 
move over those area. Unfortunately,  this heavy rain is moving 
toward the northern and central part of Bexar County, where between 
2 and 4 inches of rain have fallen since mid to late afternoon. 
Additional rainfall amounts of 1 to 2 inches are possible over the 
northern and central Bexar County with storms training and rain 
filling from the southern part of the county. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  San Antonio, New Braunfels, Schertz, Seguin, Cibolo, Converse, 
  Universal City, Live Oak, Selma, Randolph AFB, San Antonio Int 
  Airport, Canyon Lake, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Garden Ridge, Shavano Park and Hollywood Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2945 9858 2963 9861 2980 9832 2979 9814
      2975 9809 2973 9806 2961 9785 2949 9819
      2939 9846

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

OB

376 
WGUS54 KEWX 210146
FFWEWX
TXC029-091-187-210400-
/O.EXT.KEWX.FF.W.0010.000000T0000Z-260421T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
846 PM CDT Mon Apr 20 2026

The National Weather Service in Austin/San Antonio has extended the

* Flash Flood Warning for...
  Northeastern Bexar County in south central Texas...
  Southeastern Comal County in south central Texas...
  West Central Guadalupe County in south central Texas...

* Until 1100 PM CDT.

* At 846 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain moving into the central and northern parts of Bexar 
  County. Between 2 and 4 inches of rain have fallen over some of 
  these areas since mid to late afternoon. Additional rainfall 
  amounts of 1 to 2 inches are possible with a new round of storms 
  producing heavy rain. Flash flooding is ongoing or expected to 
  begin shortly. Therefore, the Flash Flood Warning has been 
  extended through 11 PM CDT.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar and rain gauges.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  San Antonio, New Braunfels, Schertz, Seguin, Cibolo, Converse, 
  Universal City, Live Oak, Selma, Randolph AFB, San Antonio Int 
  Airport, Canyon Lake, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Garden Ridge, Shavano Park and Hollywood Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2945 9858 2963 9861 2980 9832 2979 9814
      2975 9809 2973 9806 2961 9785 2949 9819
      2939 9846

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

OB

617 
WGUS74 KEWX 210332
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
1032 PM CDT Mon Apr 20 2026

TXC029-091-187-210400-
/O.CON.KEWX.FF.W.0010.000000T0000Z-260421T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Comal TX-Guadalupe TX-
1032 PM CDT Mon Apr 20 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM CDT THIS 
EVENING FOR NORTHEASTERN BEXAR, SOUTHEASTERN COMAL AND WEST CENTRAL 
GUADALUPE COUNTIES...

At 1032 PM CDT, Doppler radar and automated rain gauges indicated 
moderate to heavy rain across the warned area. Additional rainfall 
amounts up to 0.5 inches are possible over some spots in the warm 
area, however, most places are likely to get less than quarter inch 
between now and 11 PM CDT. Flash flooding likely occurring across 
low-lying and poor drainage areas. Latest radar trends showing 
things getting better over northern and central Bexar County and 
southern Comal County.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  San Antonio, New Braunfels, Schertz, Seguin, Cibolo, Converse, 
  Universal City, Live Oak, Selma, Randolph AFB, San Antonio Int 
  Airport, Canyon Lake, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Garden Ridge, Shavano Park and Hollywood Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2945 9858 2963 9861 2980 9832 2979 9814
      2975 9809 2973 9806 2961 9785 2949 9819
      2939 9846

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

OB

555 
WGUS74 KEWX 210346
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
1046 PM CDT Mon Apr 20 2026

TXC029-091-187-210356-
/O.CAN.KEWX.FF.W.0010.000000T0000Z-260421T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Comal TX-Guadalupe TX-
1046 PM CDT Mon Apr 20 2026

...FLASH FLOOD WARNING FOR NORTHEASTERN BEXAR, SOUTHEASTERN COMAL 
AND WEST CENTRAL GUADALUPE COUNTIES HAS BEEN REPLACED WITH A FLOOD 
ADVISORY...

&&

LAT...LON 2979 9814 2975 9809 2973 9806 2961 9785
      2949 9819 2939 9846 2945 9858 2963 9861
      2980 9832

$$

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
204 PM CDT Mon Apr 20 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...

- Increasing potential for localized flooding as widespread rain
  continues today into tonight, including the eastern Hill County,
  I-35 corridor, and Coastal Plains.

- Soggy weather likely to continue the eastern two-thirds of the
  area again on Tuesday.

- Cool weather continues into Tuesday with near normal
  temperatures Wednesday and a warming trend for late week.

&&

.SHORT TERM...
(Tonight through Tuesday night)
Issued at 125 PM CDT Mon Apr 20 2026

Much of South-Central Texas remains under cool and rainy
conditions as a large-scale overrunning pattern persists atop a
shallow and anomalously cold airmass for this time of year. A
sizable swath of 1 to 3 inches of rain has already fallen mainly
along and near I-10 corridor between the Hill Country and San
Antonio area, and this has already led to closure of some low-
water crossings as soils continue to saturate. VWPs from KEWX and
KDFX NEXRADs show southerly flow 1-3 km above the surface,
allowing a rich flow of elevated moisture to continue towards a
mid-level vortmax over the Permian Basin. These broad rains should
continue into Tuesday, with the mass of mostly stratiform rain
gradually shifting east with time in tandem with the mid-level
disturbance. Distinct from that feature, an upper-level shortwave
trough to the west is currently moving across northern Mexico and
will serve as a trigger for some deep convective activity
beginning in the late afternoon and continuing overnight, starting
around the Rio Grande and then along the southern edge of the
Balcones Escarpment or US-90 corridor west of San Antonio before
continuing east to the I-35 corridor and Coastal Plains overnight,
feeding on a strengthening low level jet. This will likely
enhance rainfall amounts for these areas, and potentially overlap
with areas that have already seen the highest amounts so far
today. Given continued moist ascent ahead of the approaching
trough, some of the hi-res models indicate potential for training
convection within 90th to 95th percentile PWATs. Despite cooler
temperatures and meager instability, this repetitive rains may add
a swath of additional 2-4" rain atop of what's already fallen. If
these swaths train over more built-up areas on the I-35
corridor... a distinct possibility noted in the hi-res models...
this would raise concerns for isolated urban and flash flooding,
and this is encapsulated in the WPC's level 2 of 4 (Slight) risk
for excessive rainfall today into tonight across the eastern Hill
Country, I-35 corridor and Coastal Plains. The evolution and
track of these storms will need to be closely monitored tonight.

The slower moving, mid-level disturbance currently currently to
our west will shift into Oklahoma and continue northeast tomorrow,
pushing the favored areas for ascent farther east. The hi-res
models tend to show some reduction in rain coverage Tuesday in
response, but with moist southerly transport remaining stout, rain
chances remain likely tomorrow especially along and east of I-35,
along with some isolated to scattered thunder. Temperatures will
try to warm up some as southeasterly surface flow makes a rather
unconvincing return, but persistent cloud cover will keep highs
from climbing much higher than the 60s for most of South-Central
Texas.

&&

.LONG TERM...
(Wednesday through next Monday)
Issued at 125 PM CDT Mon Apr 20 2026

A drying trend should start to kick in midweek as the nearby
disturbances aloft move farther east, allowing drier mid-level air
to return to our area. Daytime temperatures will gradually trend
towards seasonably warm levels by Wednesday. Medium chances (50
to 60 percent) for scattered showers continue through Wednesday
for the I-35 corridor and Coastal Plains, given the presence of
persistent but weaker southerly moist transport.

A prevailing moist southerly wind will stick around throughout the
second half of the week, which should eventually bring dew points
well above average by the weekend. While upper-level ridging never
truly reestablishes over our area later this week, warm air aloft
should keep more of a lid on shower activity Thursday and Friday
and accentuate a warming trend with highs in the upper 80s to low
90s. A passerby disturbance to our north is accompanied by a
slight increase in rain chances Friday, but currently these
changes are quite limited (up to about 20 percent) given the
likely capping in place. Over the weekend, amplifying troughing
over the Four Corners region may lead to another possible round of
showers and storms. The zonal orientation of the broader flow is a
limiting factor on this potential and blurs the most favorable
timing for rain, but ample conditional instability will be in
place to provide an environment suitable for thunderstorms. Highs
over the weekend are forecast to stay in the 80s to low 90s, with
lows returning humid into the 60s and low 70s with the moist south
wind.

&&

.AVIATION...
(18Z TAFS)
Issued at 1242 PM CDT Mon Apr 20 2026

A messy weather situation continues across most of the region with
a widely varied mix of lowered CIGs and VSBYs. A large area of RA
with isolated TSRA continues mostly northeast of a KERV to KSSF
line. This should persist today and tonight. Hi-res models have
struggled to capture the aviation impacts of this rain, so have
leaned towards the better performing statistical guidance in the
18Z TAFs. Overall confidence in forecast precision is low.
However, a general lowering trend in CIGs and VSBYs is likely
today, with widespread IFR to LIFR CIGs possible tonight. Models
have hinted at an increase in some TSRA mainly after 00Z, with
enough support to insert PROB30s at KAUS and KSAT. While the
overall expanse of rain should shift gradually east with time,
improvement of conditions could be quite slow, especially for
KAUS/KSAT/KSSF.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              57  69  63  82 /  80  80  40  50
Austin Bergstrom Intl Airport  58  69  63  81 /  80  80  40  50
New Braunfels Muni Airport     57  72  63  82 /  80  80  40  50
Burnet Muni Airport            55  66  60  79 /  90  80  30  30
Del Rio Intl Airport           59  78  67  83 /  60  10  30   0
Georgetown Muni Airport        57  67  62  80 /  80  80  40  40
Hondo Muni Airport             57  71  64  80 /  90  50  40  30
San Marcos Muni Airport        58  70  63  81 /  80  80  40  60
La Grange - Fayette Regional   59  72  63  81 /  80  80  40  60
San Antonio Intl Airport       59  72  65  82 /  80  70  40  50
Stinson Muni Airport           60  73  65  82 /  80  60  40  40

&&

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

SHORT TERM...Tran
LONG TERM....Tran
AVIATION...Tran

Preliminary Local Storm Report
National Weather Service Austin/San Antonio TX
219 PM CDT Mon Apr 20 2026

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

0210 PM     Flash Flood      3 WNW Live Oak          29.57N 98.38W
04/20/2026                   Bexar              TX   Emergency Mngr

            Swift water rescue near the intersection of
            Nacogdoches Road and Cattleman Street.

&&

36

Special Weather Statement
National Weather Service Austin/San Antonio TX
502 PM CDT Mon Apr 20 2026

TXZ217-218-228-202245-
Maverick TX-Dimmit TX-Zavala TX-
502 PM CDT Mon Apr 20 2026

...A strong thunderstorm will impact portions of east central
Maverick, northwestern Dimmit and southwestern Zavala Counties
through 545 PM CDT...

At 502 PM CDT, Doppler radar was tracking a strong thunderstorm near
El Indio, moving east 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...
El Indio, Rosita, and Farias Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

&&

LAT...LON 2851 10038 2854 10041 2855 10041 2858 10040
      2860 10043 2863 10044 2878 10008 2852 10001
      2850 10033
TIME...MOT...LOC 2202Z 256DEG 24KT 2857 10033

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

17