Alert archive / Texas / Severe Thunderstorm Warnings in 2006

Severe Thunderstorm Warning 14, NWS Houston/Galveston, TX

April 20, 2006Brazos County, Burleson County, Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at Apr 20, 2006, 9:04 PM CDT for Brazos County, Burleson County, Texas. It was in force for 56 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 20, 2006, 9:04 PM CDT (02:04 UTC)
Expired: Apr 20, 2006, 10:00 PM CDT
In force: 56 min
Issued by: NWS Houston/Galveston, TX
Area: Counties, with a storm outline in the text

Counties Brazos County, TX, Burleson County, TX

The radar

The Ft Hood radar (KGRK), 90 km from the middle of the area, began a volume at 02:07 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 20, 3:24 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 2.1 hours before the alert went out and 263 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 10 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 1007 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 330 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 20, 4:00 PM CDT, 5 hours 4 minutes earlier.

Area forecast discussion, Apr 20, 4:00 PM CDT, 5 hours 4 minutes before

AREA FORECAST DISCUSSION...UPDATE AVIATION AND MARINE
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
400 PM CDT THU APR 20 2006

.DISCUSSION...
CONVECTION/WATCH BOXES GETTING CLOSER THIS AFTN...BUT CURRENT TRA-
JECTORY OF STORMS AND SLIGHT SHIFT OF THE SFC BOUNDARY NORTH COULD
GIVE US SOME BREATHING ROOM (ATTM). HOWEVER...WE ARE STILL LOOKING
AT VERY GOOD POPS TONIGHT AS MODELS CONTINUE WITH THE DEVELOPMENT/
MOVEMENT OF AN MCS OVERNIGHT FROM CNTL TX ACROSS INTO E/SE TX THRU
SUNRISE. DEEPEST MOISTURE/LOWEST INSTABILITIES POOLING ALONG THE E
-W SFC BOUNDARY JUST NORTH OF THE CWFA...BUT WILL GO AHEAD AND THE
MENTION OF SEVERE FOR ALL OUR ZONES TONIGHT/EARLY FRI MORN. ROBUST
DYNAMICS/STRONG LLJ SHOULD OVERCOME THE SLIGHTLY STRONGER CAP THAT
HAS BEEN LINGERING AOA THE COAST. NOT MUCH ELSE TO ADD TO SPC DIA-
LOGUE/OUTLOOK FOR TONIGHT. WEAK FRONT TO SWEEP THRU IN THE WAKE OF
TONIGHTS ACTIVITY WITH SLIGHTLY LOWER DEWPOINTS TOMORROW. BUT S/SE
WINDS TO RETURN BY SAT. OTHERWISE THE BUILDING UPPER RIDGE TO KEEP
TEMPS JUST ABOVE SEASONAL NORMS THIS WEEKEND. GFS STILL GOING WITH
SOME LIFT/POPS MON AS A S/W INTERACTS WITH THE DRYLINE AND MOVES E
WITH TIME AS THE RIDGE BREAKS DOWN. THIS FLATTISH RIDGE PROGGED TO
HOLD MOST OF NEXT WEEK WITH MODELS STARTING TO DIVERGE ON THE TREK
AND MOVEMENT OF THE NEXT UPPER TROF. HOWEVER BOTH STILL HOLDING ON
TO THE IDEA OF A FRONT NEXT WED.
41

&&

.MARINE...
MODERATE ONSHORE WINDS THROUGH TONIGHT AS THE GRADIENT TIGHTENS IN
RESPONSE TO LOW PRESSURES OVER NORTHERN TEXAS. MESO-SCALE BOUNDARIES
FROM INLAND THUNDERSTORM DOWNDRAFTS MAY INTERRUPT AND OR MODIFY THIS
PREDOMINANT ONSHORE FLOW IF CONVECTION OVER OUR NORTHERN COUNTIES
BECOMES MORE INTENSE OVERNIGHT. WINDS WILL DECREASE FRIDAY NIGHT AS
A WEAK LARGE SCALE TROUGH APPROACHES THE COAST. NORTHEAST WINDS LATE
FRIDAY NIGHT WILL BECOME EASTERLY AS HIGH PRESSURE BUILDS EAST.
ONSHORE FLOW RESUMES LATE SUNDAY THROUGH TUESDAY. ANOTHER FRONT TO
SHIFT WINDS MORE OFFSHORE POSSIBLE WEDNESDAY.
31

&&

.AVIATION...
MVFR THROUGH 6Z. HIGH PROBABILITY OF VCTS AFTER 6Z. WINDOW FOR MOST
ACTIVE CONVECTION WILL BE BETWEEN 7Z AND 18Z ACROSS MOST NORTH
CENTRAL TERMINALS AS MAIN COMPLEX OF THUNDERSTORMS AND SHOWERS
TRAVELS FROM HILL COUNTRY NORTHEAST TOWARDS SHREVEPORT. POTENTIAL
FOR SEVERE CONDITIONS WITH CLL IN TORNADO WATCH THROUGH 10 PM.
WHETHER THUNDERSTORMS GET ACT TOGETHER IN FORMING A MULTICELL LINE
AND TRAVELING THROUGH THE HOUSTON METRO HUBS WILL BE BETTER HANDLED
BY SWING SHIFT.
31

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      65  83  60  86  63 /  70  70  10   0   0
HOUSTON (IAH)              67  84  61  86  64 /  60  60  10   0   0
GALVESTON (GLS)            70  80  67  82  69 /  20  20  10   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

Hazardous weather outlook, Apr 20, 8:28 PM CDT, 36 minutes before

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In the hours before

Local storm report, Apr 20, 8:35 PM CDT, 29 minutes before

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Local storm report, Apr 20, 8:50 PM CDT, 14 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 7:20 PM CDT	Tornado Warning	HGX	Grimes, Waller	40 min
Apr 20, 7:28 PM CDT	Tornado Warning	HGX	Washington	21 min
Apr 20, 9:30 PM CDT	Severe Thunderstorm Warning	HGX	Grimes, Madison	60 min
Apr 20, 9:56 PM CDT	Severe Thunderstorm Warning	HGX	Houston, Montgomery, Walker	64 min
Apr 20, 10:41 PM CDT	Severe Thunderstorm Warning	HGX	San Jacinto, Trinity	46 min
Apr 21, 4:44 AM CDT	Severe Thunderstorm Warning	HGX	Austin, Colorado	61 min
Apr 21, 5:23 AM CDT	Special Marine Warning	HGX		2 hr
Apr 21, 5:24 AM CDT	Severe Thunderstorm Warning	HGX	Fort Bend, Jackson, Wharton	66 min
Apr 21, 5:44 AM CDT	Severe Thunderstorm Warning	HGX	Harris	61 min
Apr 21, 6:01 AM CDT	Tornado Warning	HGX	Fort Bend	29 min
Apr 21, 6:07 AM CDT	Severe Thunderstorm Warning	HGX	San Jacinto	23 min
Apr 21, 6:15 AM CDT	Severe Thunderstorm Warning	HGX	Brazoria, Matagorda	60 min
Apr 21, 6:29 AM CDT	Severe Thunderstorm Warning	HGX	Fort Bend	31 min
Apr 21, 6:36 AM CDT	Severe Thunderstorm Warning	HGX	Polk	39 min
Apr 21, 6:42 AM CDT	Severe Thunderstorm Warning	HGX	Harris	48 min
Apr 21, 6:44 AM CDT	Special Marine Warning	HGX		2 hr
Apr 21, 6:55 AM CDT	Severe Thunderstorm Warning	HGX	Galveston	50 min
Apr 21, 7:18 AM CDT	Severe Thunderstorm Warning	HGX	Chambers	42 min
Apr 21, 7:23 AM CDT	Severe Thunderstorm Warning	HGX	Liberty	37 min
Apr 21, 8:47 AM CDT	Special Marine Warning	HGX		43 min

Nearby

Severe Thunderstorm Warnings in Texas, 2006 Every severe thunderstorm warning in 2006

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.