Alert archive / Texas / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 829, NWS Norman, OK

August 19, 2017Clay County, Texas

NWS Norman, OK issued this severe thunderstorm warning at Aug 19, 2017, 3:44 PM CDT for Clay County, Texas. It was in force for 46 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
Aug 19, 2017, 3:44 PM CDT (20:44 UTC)
Expired
Aug 19, 2017, 4:30 PM CDT
In force
46 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Clay County, TX

The radar

The Altus AFB radar (KFDR), 95 km from the middle of the area, began a volume at 20:47 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 12:00Z, 8.7 hours before the alert went out and 358 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 12:00Z on 2017-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 691 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 12:00Z on 2017-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 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
691 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
1767 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

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 Aug 19, 2:23 PM CDT, 1 hour 21 minutes earlier.

Area forecast discussion, Aug 19, 2:23 PM CDT, 1 hour 21 minutes before
Area Forecast Discussion
National Weather Service Norman OK
223 PM CDT Sat Aug 19 2017

.DISCUSSION...

&&

.PREV DISCUSSION... /issued 116 PM CDT Sat Aug 19 2017/

DISCUSSION...

The extreme heat and humidity could abate slightly Sunday as
models indicated slightly less surface moisture. For the time
being, a heat advisory is not expected for tomorrow, but that
could change. Otherwise, the upper high pressure that is over the
southern plains is forecast to move a bit westward allowing weak
influence of the westerlies into Oklahoma by Tuesday. An upper
trough through the Missouri Valley Tuesday is expected to push a
surface front into Oklahoma Tuesday night bringing a good chance
for rain and thunder across the state Tuesday night and in the
southern half of Oklahoma Wednesday. Less hot weather will follow.
Another upper system is expected from the west on Friday again
bringing good rain and thunderstorm chances. Rain chances could
last into the weekend with still modest influence from northwest
flow.

AVIATION...
VFR conditions are expected with cumulus developing through the
afternoon. Isolated thunderstorms are possible in the southwest
quarter of Oklahoma and southward. Southwest wind will mostly
remain under 12 knots.

PREV DISCUSSION... /issued 1147 AM CDT Sat Aug 19 2017/

UPDATE...
Modified POPs and recalculated hourly grids in general.

DISCUSSION...
The small showers over northern Oklahoma have dissipated, and have
removed the POPs and weather north. CAMs still suggest somewhat
higher chances in the south so have focused the POPs south.

Meanwhile after recent rains, now we have the humidity. Dewpoints
are currently at the 95th percentile for mid-August at Oklahoma
City and Wichita Falls, and 99th percentile at Ponca City. And as
we get back into the warm August weather, heat index values are
expected to be quite high. The heat advisory still looks good for
heat index of 105 to 110.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  75  97  73  93 /  10  10   0   0
Hobart OK         76  98  73  95 /  10  10  10  10
Wichita Falls TX  76  98  74  95 /  10  10   0   0
Gage OK           72  96  73  93 /  10  20  10  20
Ponca City OK     77  98  75  94 /  10  10  20  20
Durant OK         77  96  74  92 /  10  10   0  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 7 PM CDT this evening for OKZ007-008-012-013-
     018>020-024>026-028>032-040-042-043-048.

TX...None.
&&

26/09
Hazardous weather outlook, Aug 19, 11:48 AM CDT, 3 hours 56 minutes before
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In the hours before

Special weather statement, Aug 19, 2:30 PM CDT, 1 hour 14 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
230 PM CDT SAT AUG 19 2017

TXZ089-090-192000-
Clay TX-Archer TX-
230 PM CDT SAT AUG 19 2017

...SIGNIFICANT WEATHER ADVISORY FOR southwestern Clay and
southeastern Archer Counties Until 300 PM CDT...

AT 228 PM CDT, a strong thunderstorm was located 6 miles southeast of
Archer City, moving northeast at 10 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts to 40 MPH...

LAT...LON 3342 9852 3342 9877 3373 9852 3354 9829
TIME...MOT...LOC 1928Z 225DEG 9KT 3351 9856

..speg.
Special weather statement, Aug 19, 3:32 PM CDT, 12 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
332 PM CDT SAT AUG 19 2017

TXZ090-192100-
Clay TX-
332 PM CDT SAT AUG 19 2017

...SIGNIFICANT WEATHER ADVISORY FOR southwestern Clay County Until
400 PM CDT...

AT 329 PM CDT, strong thunderstorms were located 5 miles south of
Bluegrove and 8 miles southeast of Windthorst, moving northeast at
15 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 50 MPH...

LAT...LON 3347 9842 3368 9842 3375 9806 3346 9816
TIME...MOT...LOC 2029Z 233DEG 14KT 3360 9825 3348 9835

..speg.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 3:43 AM CDTHeat AdvisoryOUNAtoka, Canadian, Cleveland, Coal, Garfield, Garvin and 13 more15 hr
Aug 19, 4:42 PM CDTSpecial Weather StatementOUNJefferson33 min
Aug 19, 5:43 PM CDTSpecial Weather StatementOUNCarter32 min
Aug 19, 2:30 PM CDTSpecial Weather StatementOUNArcher30 min
Aug 19, 3:32 PM CDTSpecial Weather StatementOUNClay28 min
Aug 19, 6:29 PM CDTSpecial Weather StatementOUNFoard31 min

Nearby

Severe Thunderstorm Warnings in Texas, 2017Every severe thunderstorm warning in 2017

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.