Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 59, NWS Norman, OK

April 11, 2020Stephens County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 11, 2020, 3:12 PM CDT for Stephens County, Oklahoma. It was in force for 27 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 11, 2020, 3:12 PM CDT (20:12 UTC)
Expired
Apr 11, 2020, 3:39 PM CDT
In force
27 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
2.0 in
Wind
70.0 mph

County Stephens County, OK

The radar

The Altus AFB radar (KFDR), 104 km from the middle of the area, began a volume at 20:15 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.

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 Apr 11, 1:53 PM CDT, 1 hour 19 minutes earlier.

Area forecast discussion, Apr 11, 1:53 PM CDT, 1 hour 19 minutes before
Area Forecast Discussion
National Weather Service Norman OK
153 PM CDT Sat Apr 11 2020

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Sunday)
Issued at 121 PM CDT Sat Apr 11 2020

Moisture advection and destabilization continues through the
region, in particular through western Oklahoma and western north
Texas. The airmass in western north Texas has been relatively
unmodified from the morning storms. These storms have not been as
widespread and have remained mostly south of the CWA, and is now
impacting the far southeast Oklahoma counties with rain,
lightning, and some small hail.

Out in western Texas and the Texas Panhandle, visible satellite
show cumulus towers developing and bubbling up. The environment in
the area is a bit concerning, with increasing CAPE throughout the
area. CAMs soundings indicate plenty of low level instability
(SBCAPE & MLCAPE > 2000 J/kg), and a curved hodograph with strong
enough low level shear (SFC-1km Shear > 20kts, SRH > 300 in
areas). The possibility is there for isolated supercells with all
hazards possible: large hail, severe winds, and a possible
tornado. There are a few failure modes to watch out for. If these
storms do not remain surface based, tornado chances will drop
however the hail and wind threat will remain. Also currently the
visible satellite looks a bit junky, which may limit the severity
if the storms continue to remain unorganized.

As these storms exit the area into Sunday, winds will increase
significantly as the strong cold front enters northwestern Oklahoma.
Winds will intensify to a sustained greater than 35mph, with gusts
possible in the 40-50mph range. With these high winds, a wind
advisory will be issued for most of western into central Oklahoma,
as well as parts of western north Texas.

Zwink

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 121 PM CDT Sat Apr 11 2020

Behind the cold front, much colder air will result in significant
temperature drops in the region, with many areas dropping below
freezing throughout northern, central, and western Oklahoma. With it
being mid April and the chance for a late season freeze, a Freeze
warning will likely be issued as the event gets closer. Late Monday
into Tuesday, a shortwave trough moves through the area in
conjunction with some Pacific midlevel moisture, which will result
in widespread precipitation. With the deep cold airmass in place,
there is a chance for snow throughout northwestern Oklahoma and
parts of central Oklahoma. Accumulations will likely be limited by
ground temperatures, however model soundings indicate heavy snow may
be possible in some areas which might overcome the warm ground
temperatures.

Cold temperatures are expected to linger until Wednesday, where
temperatures will gradually warm up through the remainder of the
week. Next chance of precipitation appears to be late next week with
an approaching upper level cyclone.

Zwink

&&

.AVIATION...
(18Z TAFS)
Issued at 1211 PM CDT Sat Apr 11 2020

Much of the area continue to see MVFR ceilings this afternoon and
this is likely to continue as gusty south winds continue to pull
moisture northward. There will be a chance for TSRA at most sites
this afternoon and tonight before things clear out after 09Z.
Strong cold front will impact WWR before end of forecast period
with wind gusts of 35 to 40kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  58  75  31  48 /  40  30   0  10
Hobart OK         54  72  30  48 /  40  10   0  10
Wichita Falls TX  59  76  34  52 /  40  20   0  10
Gage OK           48  62  25  46 /  20  10   0  10
Ponca City OK     57  72  29  49 /  30  50   0  10
Durant OK         59  75  35  53 /  60  80   0  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

SHORT TERM...50
LONG TERM....50
AVIATION...30
Hazardous weather outlook, Apr 11, 11:45 AM CDT, 3 hours 27 minutes before
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In the hours before

Special weather statement, Apr 11, 1:58 PM CDT, 1 hour 14 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
158 PM CDT Sat Apr 11 2020

OKZ037-038-044-TXZ086-111930-
Tillman OK-Cotton OK-Comanche OK-Wichita TX-
158 PM CDT Sat Apr 11 2020

...SIGNIFICANT WEATHER ADVISORY FOR southeastern Tillman...west
central Cotton...southwestern Comanche and northwestern Wichita
Counties Until 230 PM CDT...

AT 154 PM CDT, a strong thunderstorm was located 6 miles south of
Hollister, moving northeast at 45 MPH.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 3418 9895 3421 9895 3421 9896 3420 9897
      3421 9897 3422 9899 3422 9900 3427 9907
      3452 9872 3428 9843 3413 9889
TIME...MOT...LOC 1854Z 235DEG 41KT 3425 9887

30
Local storm report, Apr 11, 2:53 PM CDT, 19 minutes before
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Local storm report, Apr 11, 3:11 PM CDT, 1 minute before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 1:58 PM CDTSpecial Weather StatementOUNTillman32 min
Apr 11, 2:00 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Tillman45 min
Apr 11, 2:09 PM CDTWind AdvisoryOUNAlfalfa, Beckham, Blaine, Caddo, Canadian, Carter and 37 more32 hr
Apr 11, 2:41 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Stephens49 min
Apr 11, 3:21 PM CDTSevere Thunderstorm WarningOUNCarter, Garvin, Grady, McClain, Murray, Stephens39 min
Apr 11, 3:24 PM CDTSpecial Weather StatementOUNAlfalfa36 min
Apr 11, 3:55 PM CDTSevere Thunderstorm WarningOUNGarvin, Murray, Pontotoc23 min
Apr 11, 4:59 PM CDTSpecial Weather StatementOUNHarmon31 min
Apr 11, 5:00 PM CDTSpecial Weather StatementOUNPontotoc30 min
Apr 11, 5:55 PM CDTSevere Thunderstorm WarningOUNBeckham, Greer, Harmon50 min
Apr 11, 6:11 PM CDTTornado WarningOUNHarmon14 min
Apr 11, 6:17 PM CDTSevere Thunderstorm WarningOUNGreer, Harmon, Jackson43 min
Apr 11, 6:46 PM CDTSevere Thunderstorm WarningOUNJackson44 min
Apr 11, 6:49 PM CDTSevere Thunderstorm WarningOUNGreer, Harmon, Jackson41 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2020Every severe thunderstorm warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.