Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 38, NWS San Angelo, TX

August 18, 2021Brown County, Callahan County, Coleman County, Texas

NWS San Angelo, TX issued this flash flood warning at Aug 18, 2021, 8:12 AM CDT for Brown County, Callahan County, Coleman County, Texas. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 18, 2021, 8:12 AM CDT (13:12 UTC)
Expired
Aug 18, 2021, 11:15 AM CDT
In force
3 hr
Issued by
NWS San Angelo, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Brown County, TX, Callahan County, TX, Coleman County, TX

The radar

The Dyess AFB radar (KDYX), 62 km from the middle of the area, began a volume at 13:11 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 1.2 hours before the alert went out and 214 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Fort Worth, TX at 12:00Z on 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 500 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2021-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
500 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
580 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
-2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

142 
WGUS54 KSJT 181312
FFWSJT
TXC049-059-083-181615-
/O.NEW.KSJT.FF.W.0038.210818T1312Z-210818T1615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Angelo TX
812 AM CDT Wed Aug 18 2021

The National Weather Service in San Angelo has issued a

* Flash Flood Warning for...
  Northwestern Brown County in west central Texas...
  Southern Callahan County in west central Texas...
  Northern Coleman County in west central Texas...

* Until 1115 AM CDT.

* At 811 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. 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...
  Coleman, Cross Plains, Novice, Burkett, Silver Valley, Cross Cut, 
  Grosvenor, Oplin, Glen Cove, Lake Brownwood, Valera, Talpa, May, 
  Echo, Lake Coleman and Hords Creek Reservoir.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3216 9962 3229 9942 3236 9912 3208 9912
      3208 9892 3200 9887 3188 9905 3173 9921
      3175 9927 3181 9933 3171 9952 3167 9972
      3208 9971 3208 9963

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

$$

SN

The office that day

Everything else NWS San Angelo, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 4:46 AM CDTAreal Flood AdvisorySJTRunnels119 min
Aug 18, 6:54 AM CDTAreal Flood AdvisorySJTCallahan, Coleman2 hr
Aug 18, 10:13 AM CDTFlash Flood WarningSJTCallahan3 hr
Aug 18, 11:25 AM CDTAreal Flood AdvisorySJTShackelford3 hr
Aug 18, 12:42 PM CDTFlash Flood WarningSJTRunnels3 hr
Aug 18, 1:13 PM CDTFlash Flood Warning Considerable damage threatSJTCallahan, Coleman3 hr
Aug 18, 1:56 PM CDTAreal Flood AdvisorySJTCoke, Runnels3 hr

Nearby

Flash Flood Warnings in Texas, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.