Alert archive / Texas / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 41, NWS Houston/Galveston, TX
NWS Houston/Galveston, TX issued this severe thunderstorm warning at Apr 12, 2009, 9:27 AM CDT for 4 counties in Texas. It was in force for 48 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
- Apr 12, 2009, 9:27 AM CDT (14:27 UTC)
- Expired
- Apr 12, 2009, 10:15 AM CDT
- In force
- 48 min
- Issued by
- NWS Houston/Galveston, TX
- Area
- Storm-based polygon
Counties Montgomery County, TX, San Jacinto County, TX, Trinity County, TX, Walker County, TX
The radar
The Houston radar (KHGX), 136 km from the middle of the area, began a volume at 14:31 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Apr 12, 7:58 AM CDT | Tornado Watch | SPC | 8 hr |
The nearest sounding before it
Lake Charles Mun, LA (KLCH), launched 12:00Z, 2.5 hours before the alert went out and 215 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.
- Mixed-layer CAPE
- 880 J/kg
- Mixed-layer CIN
- -259 J/kg
- Mixed-layer LCL
- 506 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 326 m²/s²
- 0-3 km storm-relative helicity
- 463 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.3
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Houston/Galveston, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 12, 6:49 AM CDT, 2 hours 38 minutes earlier.
Area forecast discussion, Apr 12, 6:49 AM CDT, 2 hours 38 minutes before
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</html>Hazardous weather outlook, Apr 12, 4:12 AM CDT, 5 hours 15 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 412 AM CDT SUN APR 12 2009 GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226- 227-235>238-122030- AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND- GALVESTON-GALVESTON BAY-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY- MADISON-MATAGORDA-MATAGORDA BAY-MONTGOMERY-POLK-SAN JACINTO- TRINITY-WALKER-WALLER-WASHINGTON- WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM- WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM- WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM- WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON- 412 AM CDT SUN APR 12 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS. ...STRONG TO SEVERE STORMS POSSIBLE THIS MORNING INTO EARLY AFTERNOON... .DAY ONE...TODAY A STRONG STORM SYSTEM WILL MOVE ACROSS NORTH TEXAS TODAY. THE AIR MASS IS UNSTABLE AND SOME OF THE STORMS WILL BE STRONG TO SEVERE. THE PRIMARY SEVERE WEATHER HAZARD WILL BE DAMAGING WINDS. LOW LEVEL WIND SHEAR WILL BE STRONG AND THIS WILL SUPPORT THE DEVELOPMENT OF TORNADOES. THE BEST CHANCE FOR STORMS WILL BE DURING THE MORNING AND EARLY AFTERNOON HOURS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... EMERGENCY MANAGERS AND STORM SPOTTERS SHOULD PREPARE FOR POSSIBLE ACTIVATION THIS MORNING.
The office that day
Everything else NWS Houston/Galveston, TX issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 12, 8:52 AM CDT | Severe Thunderstorm Warning | HGX | Houston, Madison, Walker | 38 min |
| Apr 12, 9:41 AM CDT | Small Craft Advisory | HGX | 5 hr | |
| Apr 12, 9:46 AM CDT | Severe Thunderstorm Warning | HGX | Polk, San Jacinto, Trinity, Walker | 44 min |
| Apr 12, 10:42 AM CDT | Severe Thunderstorm Warning | HGX | Polk, San Jacinto | 34 min |
| Apr 12, 11:24 AM CDT | Severe Thunderstorm Warning | HGX | Fort Bend, Harris, Montgomery | 51 min |
| Apr 12, 11:39 AM CDT | Severe Thunderstorm Warning | HGX | Liberty, Montgomery, San Jacinto | 14 min |
| Apr 12, 11:51 AM CDT | Tornado Warning | HGX | Harris | 39 min |
| Apr 12, 12:15 PM CDT | Severe Thunderstorm Warning | HGX | Chambers, Harris, Liberty | 45 min |
| Apr 12, 12:17 PM CDT | Tornado Warning | HGX | Chambers, Harris, Liberty | 43 min |
| Apr 12, 12:22 PM CDT | Special Marine Warning | HGX | 83 min | |
| Apr 12, 12:53 PM CDT | Severe Thunderstorm Warning | HGX | Chambers, Liberty | 52 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.