Alert archive / Texas / Tornado Warnings in 2021

Tornado Warning 25, NWS Houston/Galveston, TX

August 12, 2021Harris County, Texas

NWS Houston/Galveston, TX issued this tornado warning at Aug 12, 2021, 4:35 PM CDT for Harris County, Texas. It was in force for 25 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 12, 2021, 4:35 PM CDT (21:35 UTC)
Expired
Aug 12, 2021, 5:00 PM CDT
In force
25 min
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Tornado
Observed
Hail
0.75 in

County Harris County, TX

The radar

The Houston radar (KHGX), 82 km from the middle of the area, began a volume at 21:37 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.

What was reported inside it

TimeReportWhereRemark
Aug 12, 4:37 PM CDTTORNADO5 Sw Cypress, TXHarris County Pct. 5 constables reporting tornado. Airborne debris and 5 telephone poles downed.
Aug 12, 4:37 PM CDTTORNADO5 Sw Cypress, TXHARRIS COUNTY PCT. 5 CONSTABLES REPORTING TORNADO. AIRBORNE DEBRIS AND 5 TELEPHONE POLES DOWNED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 9.6 hours before the alert went out and 245 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2387 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -48 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
2387 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
813 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
0 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

368 
WFUS54 KHGX 122135
TORHGX
TXC201-122200-
/O.NEW.KHGX.TO.W.0025.210812T2135Z-210812T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Houston/Galveston TX
435 PM CDT Thu Aug 12 2021

The National Weather Service in League City has issued a

* Tornado Warning for...
  West central Harris County in southeastern Texas...

* Until 500 PM CDT.

* At 434 PM CDT, law enforcement and trained spotters reported a 
  tornado located near Cypress, or 10 miles west of Jersey Village, 
  moving northwest at 15 mph.

  HAZARD...Damaging tornado.

  SOURCE...Law enforcement confirmed tornado.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This tornadic thunderstorm will remain over mainly rural areas of
  west central Harris County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to a basement or an interior room on the lowest floor of a 
sturdy building. Avoid windows. If you are outdoors, in a mobile 
home, or in a vehicle, move to the closest substantial shelter and 
protect yourself from flying debris.

&&

LAT...LON 2991 9569 2989 9574 2998 9583 3002 9574
TIME...MOT...LOC 2134Z 145DEG 12KT 2994 9574 

TORNADO...OBSERVED
HAIL...<.75IN

$$
2 follow-up statements
385 
WWUS54 KHGX 122146
SVSHGX

Severe Weather Statement
National Weather Service Houston/Galveston TX
446 PM CDT Thu Aug 12 2021

TXC201-122200-
/O.CON.KHGX.TO.W.0025.000000T0000Z-210812T2200Z/
Harris TX-
446 PM CDT Thu Aug 12 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM CDT FOR WEST
CENTRAL HARRIS COUNTY...
    
At 434 PM CDT, law enforcement and trained spotters reported a 
tornado located near Cypress, or 10 miles west of Jersey Village, 
moving northwest at 15 mph. Later, law enforcement reported multiple 
power poles downed near the intersection of Tuckerton Rd and Fry Rd.

HAZARD...Damaging tornado.

SOURCE...Law enforcement confirmed tornado.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to a basement or an interior room on the lowest floor of a 
sturdy building. Avoid windows. If you are outdoors, in a mobile 
home, or in a vehicle, move to the closest substantial shelter and 
protect yourself from flying debris.

&&

LAT...LON 2991 9569 2989 9574 2998 9583 3002 9574
TIME...MOT...LOC 2144Z 145DEG 12KT 2997 9576 

TORNADO...OBSERVED
HAIL...<.75IN

$$
Cady
139 
WWUS54 KHGX 122154
SVSHGX

Severe Weather Statement
National Weather Service Houston/Galveston TX
454 PM CDT Thu Aug 12 2021

TXC201-122203-
/O.EXP.KHGX.TO.W.0025.000000T0000Z-210812T2200Z/
Harris TX-
454 PM CDT Thu Aug 12 2021

...THE TORNADO WARNING FOR WEST CENTRAL HARRIS COUNTY WILL EXPIRE AT
500 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 2991 9569 2989 9574 2998 9583 3002 9574
TIME...MOT...LOC 2153Z 145DEG 12KT 2997 9577 

$$
Cady

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 5:15 PM CDTSpecial Weather StatementHGXMontgomery30 min

Nearby

Tornado Warnings in Texas, 2021Every tornado warning in 2021Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.