Alert archive / Texas / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 99, NWS Houston/Galveston, TX

May 11, 2009Montgomery County, San Jacinto County, Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at May 11, 2009, 5:08 PM CDT for Montgomery County, San Jacinto County, Texas. It was in force for 52 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 11, 2009, 5:08 PM CDT (22:08 UTC)
Expired
May 11, 2009, 6:00 PM CDT
In force
52 min
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon

Counties Montgomery County, TX, San Jacinto County, TX

The radar

The Houston radar (KHGX), 110 km from the middle of the area, began a volume at 22:11 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

Shreveport, LA (KSHV), launched 12:00Z, 10.1 hours before the alert went out and 272 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, Shreveport, LA at 12:00Z on 2009-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 129 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2009-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 147 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
129 J/kg
Mixed-layer CIN
-187 J/kg
Mixed-layer LCL
458 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
147 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
May 11, 1:42 PM CDTSevere Thunderstorm WarningHGXHarris, Liberty, Montgomery24 min
May 11, 2:09 PM CDTSevere Thunderstorm WarningHGXAustin, Grimes, Harris, Waller51 min
May 11, 2:10 PM CDTSevere Thunderstorm WarningHGXLiberty50 min
May 11, 2:49 PM CDTSevere Thunderstorm WarningHGXHarris, Liberty41 min
May 11, 2:52 PM CDTSevere Thunderstorm WarningHGXAustin, Colorado, Waller53 min
May 11, 3:15 PM CDTAreal Flood AdvisoryHGXHarris2 hr
May 11, 3:27 PM CDTSevere Thunderstorm WarningHGXLiberty, Polk, San Jacinto48 min
May 11, 3:41 PM CDTSpecial Marine WarningHGX64 min
May 11, 4:45 PM CDTSevere Thunderstorm WarningHGXLiberty, San Jacinto27 min
May 11, 6:04 PM CDTSevere Thunderstorm WarningHGXMontgomery41 min

Nearby

Severe Thunderstorm Warnings in Texas, 2009Every severe thunderstorm warning in 2009

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.