Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 433, NWS Norman, OK

July 27, 2021Johnston County, Marshall County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jul 27, 2021, 4:15 PM CDT for Johnston County, Marshall County, Oklahoma. It was in force for 15 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 27, 2021, 4:15 PM CDT (21:15 UTC)
Expired
Jul 27, 2021, 4:30 PM CDT
In force
15 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Johnston County, OK, Marshall County, OK

The radar

The Norman radar (KTLX), 135 km from the middle of the area, began a volume at 21:16 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

Norman, OK (KOUN), launched 12:00Z, 9.3 hours before the alert went out and 128 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, Norman, OK at 12:00Z on 2021-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1050 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 12:00Z on 2021-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939Sfc1 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
1050 J/kg
Mixed-layer CIN
-157 J/kg
Mixed-layer LCL
1417 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

121 
WUUS54 KOUN 272115
SVROUN
OKC069-095-272130-
/O.NEW.KOUN.SV.W.0433.210727T2115Z-210727T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
415 PM CDT Tue Jul 27 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Southwestern Johnston County in southeastern Oklahoma...
  North central Marshall County in southeastern Oklahoma...

* Until 430 PM CDT.

* At 415 PM CDT, a severe thunderstorm was located near Madill,
  moving south at 10 to 20 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Mannsville and Russett. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3419 9689 3423 9676 3414 9672 3412 9687
TIME...MOT...LOC 2115Z 341DEG 19KT 3413 9679 

HAIL...0.88IN
WIND...60MPH
 
$$

SIX

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 7:24 PM CDTSpecial Weather StatementOUNPontotoc36 min
Jul 26, 7:53 PM CDTSpecial Weather StatementOUNPontotoc37 min
Jul 27, 7:42 AM CDTHeat AdvisoryOUNAtoka, Bryan, Coal, Hughes, Johnston, Kay and 7 more11 hr
Jul 27, 12:33 PM CDTHeat AdvisoryOUNAtoka, Bryan, Canadian, Carter, Cleveland, Coal and 22 more30 hr
Jul 27, 3:37 PM CDTSpecial Weather StatementOUNBryan23 min
Jul 27, 3:41 PM CDTSpecial Weather StatementOUNPontotoc19 min
Jul 27, 4:06 PM CDTSpecial Weather StatementOUNMarshall24 min
Jul 27, 4:20 PM CDTSpecial Weather StatementOUNBryan25 min
Jul 27, 4:29 PM CDTSpecial Weather StatementOUNPontotoc31 min
Jul 27, 4:37 PM CDTSpecial Weather StatementOUNCanadian23 min
Jul 27, 4:39 PM CDTSpecial Weather StatementOUNMarshall36 min
Jul 27, 4:45 PM CDTSpecial Weather StatementOUNJohnston30 min
Jul 27, 5:11 PM CDTSpecial Weather StatementOUNKiowa34 min
Jul 27, 6:07 PM CDTSpecial Weather StatementOUNCoal23 min
Jul 27, 6:22 PM CDTSpecial Weather StatementOUNOklahoma38 min
Jul 27, 6:49 PM CDTSpecial Weather StatementOUNSeminole26 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2021Every severe thunderstorm warning in 2021

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.