Alert archive / Texas / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 76, NWS Houston/Galveston, TX

August 11, 2021Harris County, Montgomery County, Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at Aug 11, 2021, 3:18 PM CDT for Harris County, Montgomery County, Texas. It was in force for 27 min. 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 11, 2021, 3:18 PM CDT (20:18 UTC)
Expired
Aug 11, 2021, 3:45 PM CDT
In force
27 min
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Harris County, TX, Montgomery County, TX

The radar

The Houston radar (KHGX), 70 km from the middle of the area, began a volume at 20:17 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 8.3 hours before the alert went out and 225 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, Lake Charles Mun, LA at 12:00Z on 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3222 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, Lake Charles Mun, LA at 12:00Z on 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -49 square meters per square second.1939Sfc1 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
3222 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
742 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-49 m²/s²
0-3 km storm-relative helicity
-42 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

455 
WUUS54 KHGX 112018
SVRHGX
TXC201-339-112045-
/O.NEW.KHGX.SV.W.0076.210811T2018Z-210811T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Houston/Galveston TX
Issued by National Weather Service Corpus Christi TX
318 PM CDT Wed Aug 11 2021

The National Weather Service in League City has issued a

* Severe Thunderstorm Warning for...
  Southwestern Montgomery County in southeastern Texas...
  Northwestern Harris County in southeastern Texas...

* Until 345 PM CDT.

* At 318 PM CDT, a severe thunderstorm was located over Willowbrook,
  or near Jersey Village, moving northwest at 15 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Tomball, Jersey Village, Greater Greenspoint, Spring Branch North,
  Hooks Airport, Westbranch, Fairbanks / Northwest Crossing,
  Langwood, Willowbrook, Cypress, Greater Inwood, Carverdale, Spring
  Branch Central, Hidden Valley, northwestern Acres Home, Spring
  Branch East and Central Northwest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 2996 9538 2981 9549 2993 9579 3015 9562
TIME...MOT...LOC 2018Z 123DEG 13KT 2993 9551 

HAIL...1.00IN
WIND...<50MPH
 
$$

JCP

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 11, 4:33 AM CDTHeat AdvisoryHGXAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more15 hr
Aug 11, 2:30 PM CDTSpecial Weather StatementHGXLiberty45 min
Aug 11, 3:04 PM CDTSpecial Weather StatementHGXHarris41 min
Aug 11, 3:43 PM CDTAreal Flood AdvisoryHGXHarris3 hr
Aug 11, 3:47 PM CDTSpecial Weather StatementHGXWaller43 min
Aug 11, 3:57 PM CDTSpecial Weather StatementHGXFort Bend48 min
Aug 11, 4:28 PM CDTSevere Thunderstorm WarningHGXMontgomery, Walker32 min

Nearby

Severe Thunderstorm Warnings in Texas, 2021Every severe thunderstorm 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.