Flash Flood Warning 11, NWS Austin/San Antonio, TX

377 
WGUS54 KEWX 211346
FFWEWX
TXC491-211715-
/O.EXT.KEWX.FF.W.0011.000000T0000Z-260421T1715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
846 AM CDT Tue Apr 21 2026

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

* Flash Flood Warning for...
  Central Williamson County in south central Texas...

* Until 1215 PM CDT.

* At 846 AM CDT, Emergency management reported 16 low water 
  crossings are closed due to flooding throughout Williamson County. 
  Between 2 and 4 inches of rain have fallen. Additional rainfall 
  amounts of 1 to 2 inches are possible in the warned area. Flash 
  flooding is already occurring.

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

  SOURCE...Emergency management reported.

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

* Some locations that will experience flash flooding include...
  Round Rock, Georgetown, Taylor, Serenada, Leander, Hutto, Liberty 
  Hill, Jarrell, Florence, Thrall, Weir, Georgetown Dam, Sun City, 
  Andice, Coupland, Jonah, Walburg, Theon, Waterloo and Seward 
  Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

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 3058 9768 3067 9797 3087 9780 3061 9724
      3048 9735

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MM

990 
WGUS54 KEWX 211643
FFWEWX
TXC491-212015-
/O.EXT.KEWX.FF.W.0011.000000T0000Z-260421T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1143 AM CDT Tue Apr 21 2026

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

* Flash Flood Warning for...
  Central Williamson County in south central Texas...

* Until 315 PM CDT.

* At 1143 AM CDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  2 and 5 inches of rain have fallen. Additional rainfall amounts up 
  to 1 inch are possible in the warned area. Flash flooding is 
  already occurring.

  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...
  Round Rock, Georgetown, Taylor, Serenada, Leander, Hutto, Liberty 
  Hill, Jarrell, Florence, Thrall, Weir, Georgetown Dam, Sun City, 
  Andice, Coupland, Jonah, Walburg, Theon, Waterloo and Seward 
  Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3058 9768 3067 9797 3087 9780 3061 9724
      3048 9735

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

$$

MM

214 
WGUS54 KEWX 212001
FFWEWX
TXC491-212315-
/O.EXT.KEWX.FF.W.0011.000000T0000Z-260421T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
301 PM CDT Tue Apr 21 2026

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

* Flash Flood Warning for...
  Central Williamson County in south central Texas...

* Until 615 PM CDT.

* At 301 PM CDT, Emergency management reported several low water 
  crossings remain closed due to flooding throughout Williamson 
  County. Between 2 and 4 inches of rain have fallen. Additional 
  rainfall amounts up to 1 inch are possible in the warned area. 
  Flash flooding is already occurring.

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

  SOURCE...Emergency management reported.

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

* Some locations that will experience flash flooding include...
  Round Rock, Georgetown, Taylor, Serenada, Leander, Hutto, Liberty 
  Hill, Jarrell, Florence, Thrall, Weir, Georgetown Dam, Sun City, 
  Andice, Coupland, Jonah, Walburg, Theon, Waterloo and Seward 
  Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3058 9768 3067 9797 3087 9780 3061 9724
      3048 9735

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

TRAN

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
544 AM CDT Tue Apr 21 2026

...New AVIATION...

.KEY MESSAGES...

- Soggy weather likely to continue for the eastern two-thirds of
  the area again today.

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

&&

.SHORT TERM...
(Today through Wednesday)
Issued at 123 AM CDT Tue Apr 21 2026

Showers and isolated thunderstorms are currently ongoing across the
area at this hour with activity expected to continue for a few more
hours and perhaps decrease as the shortwave responsible pushes off
to the north and east. We could see some more redevelopment in the
overnight/early morning hours as half of the Hi-Res models suggest.
However, they haven't exactly done the best job regarding
yesterday's activity and even last night's so confidence in this
scenario playing out is low. Most model guidance once again
continues to suggest that activity picks up in intensity and areal
coverage basically across the eastern two thirds of our area. This
does make sense as very moist southerly transport remains across the
area helping to set up a possible boundary similar to the one that
occurred yesterday. This one however, would possibly be located
further north and impacting areas along the I-35 Corridor and areas
east across the Coastal Plains. The HREF PMM 24 hour QPF is still
showing a wide swath of 2-3 inches in this area. Certainly something
that bears watching especially if we have a similar setup like we
had over Bexar, Comal, and parts of Guadalupe county yesterday.
Expect rain cooled air and CAA once again to limit afternoon high
temperatures with most barely hitting 70 degrees. Main exception
would be for those under a developing shortwave ridge out west. As a
result, areas across the Rio Grande plains and far southern counties
can expect to see highs in the mid to upper 70s.

Tonight we should see rain chances decrease somewhat before a second
wave of energy moves back into the area helping to kick off more
showers and isolated storms with our overrunning/isentropic lift
type pattern still continuing into early Wednesday. We finally start
to dry out by Wednesday afternoon with areas along and east of I-35
continuing to see the highest rain chances.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 123 AM CDT Tue Apr 21 2026

All activity should finish by Wednesday night as most precipitation
finally pushes off to the east and out of our area. Thursday and
Friday should be a much drier days as southerly low level flow
returns and with it the possibility for some isolated streamer
showers over the Coastal plains on Friday. Temps should warm up
nicely back into the mid 80s on Thursday and into the upper 80s by
Friday. Our quieter and drier weather is short lived as a trough out
west begins to deepen helping to bring us back into southwest flow.
As a result, thunderstorms appear possible for both Saturday and
Sunday given the setup in place.

&&

.AVIATION...
(12Z TAFS)
Issued at 539 AM CDT Tue Apr 21 2026

Ceilings at all terminals are IFR/LIFR and will not improve much
until this afternoon. Even at that point they will only improve
around one category. Visibilities are also reduced this morning in
fog and occasional rain. This will also continue through the
morning. Rain should come to an end during the afternoon. Very low
ceilings will continue in the Austin and San Antonio areas through
this period. DRT will improve to VFR for the evening, but then
drop back down to IFR overnight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              68  63  82  67 /  90  30  50  10
Austin Bergstrom Intl Airport  69  63  82  67 /  90  30  50  10
New Braunfels Muni Airport     70  63  82  66 /  80  30  50   0
Burnet Muni Airport            65  62  79  65 /  80  30  30   0
Del Rio Intl Airport           78  68  83  68 /  10  10   0   0
Georgetown Muni Airport        66  62  80  67 /  90  40  40  10
Hondo Muni Airport             74  65  82  65 /  40  30  20   0
San Marcos Muni Airport        69  63  81  66 /  80  30  50   0
La Grange - Fayette Regional   70  63  81  67 /  80  30  60  10
San Antonio Intl Airport       71  65  82  67 /  70  30  50   0
Stinson Muni Airport           73  67  83  67 /  60  30  50   0

&&

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

SHORT TERM...CJM
LONG TERM....CJM
AVIATION...05