Alert archive / Texas / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 647, NWS Norman, OK

September 30, 2004Knox County, Texas

NWS Norman, OK issued this severe thunderstorm warning at Sep 30, 2004, 8:26 PM CDT for Knox County, Texas. It was in force for 49 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
Sep 30, 2004, 8:26 PM CDT (01:26 UTC)
Expired
Sep 30, 2004, 9:15 PM CDT
In force
49 min
Issued by
NWS Norman, OK
Area
Counties, with a storm outline in the text

County Knox County, TX

The radar

The Altus AFB radar (KFDR), 110 km from the middle of the area, began a volume at 01:27 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

Amarillo Airport, TX (KAMA), launched 00:00Z, 1.4 hours before the alert went out and 255 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, Amarillo Airport, TX at 00:00Z on 2004-10-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1185 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, Amarillo Airport, TX at 00:00Z on 2004-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 square meters per square second.19395878Sfc1 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
1185 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
1035 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

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 Norman, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 30, 2:23 PM CDT, 6 hours 3 minutes earlier.

Area forecast discussion, Sep 30, 2:23 PM CDT, 6 hours 3 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
223 PM CDT THU SEP 30 2004

.DISCUSSION...
LIKELY POPS REMAIN FOR MOST AREAS TONIGHT WITH THE APPROACH OF THE
STRONG UPPER JET FROM THE WEST. STORMS IN SOUTHEAST NM AT
MID-AFTERNOON APPEAR ASSOCIATED WITH THIS FEATURE WHICH WILL BE
TRANSLATING ACROSS THE TX PANHANDLE AND INTO THE MAIN BODY OF OK
OVERNIGHT. AFTER SUNRISE FRIDAY, THE UPPER WAVE SHOULD LIFT TO THE
NORTHEAST OF OK AND THE SURFACE FRONT WILL LIKELY SURGE SOUTH DURING
THE AFTERNOON. MORE SHOWERS AND STORMS MAY OCCUR ALONG THE FRONT,
BUT THE MAIN TIME FOR RAIN WILL BE OVERNIGHT TONIGHT.

BOTH THE ETA AND GFS SHOW THE FRONT THROUGH OK BY 06Z SAT WITH A
COOL AND DRY AIRMASS SETTLING OVER THE SOUTHERN PLAINS SATURDAY AND
SUNDAY MORNING. A SECOND FRONT WILL LIKELY MOVE ACROSS OK SUNDAY
NIGHT OR MONDAY, BUT RAIN CHANCES WILL BE LOW WITH LIMITED MOISTURE
AND LITTLE UPPER SUPPORT.

THE UNSETTLED NATURE OF NEXT WEEK STILL SEEMS THE BEST SCENARIO AS
SEVERAL WEAK WAVES COULD MOVE OUT OF THE WEAK FLOW ACROSS THE
SOUTHWEST U.S. BY MID-WEEK. THIS WOULD BE BEFORE A MORE SUBSTANTIAL
UPPER TROUGH WOULD PUSH THIS WEAK LOW ACROSS THE SOUTHWEST AND
SOUTHERN PLAINS. POPS REMAIN IN THE FORECAST WEDNESDAY AND THURSDAY.

SATURDAY NIGHT WILL LIKELY BE OUR COOLEST NIGHT OF THE SEASON FOR
THE NEXT WEEK AS SOME SUB-40 TEMPERATURES MAY BE OBSERVED IN
NORTHERN OK.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  63  81  48  69 /  70  40  30  10
HOBART OK         62  81  48  70 /  70  30  30  10
WICHITA FALLS TX  65  86  52  71 /  70  30  30  20
GAGE OK           59  76  42  69 /  40  30  20  10
PONCA CITY OK     63  79  45  67 /  70  40  20  10
DURANT OK         64  83  55  71 /  70  50  40  20

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.

&&

9
Hazardous weather outlook, Sep 30, 11:55 AM CDT, 8 hours 31 minutes before
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In the hours before

Special weather statement, Sep 30, 8:11 PM CDT, 15 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
811 PM CDT THU SEP 30 2004

TXZ087-010145-

KNOX TX-
811 PM CDT THU SEP 30 2004

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR KNOX COUNTY.

A STRONG THUNDERSTORM WAS LOCATED 27 MILES WEST OF BENJAMIN AT 811 PM
CDT...MOVING NORTHEAST AT 35 MPH.  WINDS TO 50 MPH AND SOME HAIL
ARE LIKELY WITH THIS STORM.

PEOPLE IN KNOX COUNTY SHOULD MONITOR THE WEATHER SITUATION CLOSELY.
LISTEN FOR WARNINGS AND REMAIN ALERT FOR THREATENING WEATHER
CONDITIONS.

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 30, 9:08 PM CDTSevere Thunderstorm WarningOUNTillman37 min
Sep 30, 9:12 PM CDTSevere Thunderstorm WarningOUNJackson48 min

Nearby

Severe Thunderstorm Warnings in Texas, 2004Every severe thunderstorm warning in 2004

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.