Alert archive / Oklahoma / Mesoscale Discussions in 2011

Mesoscale Discussion 2187

September 17, 201134 counties in Oklahoma; 4 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 17, 2011, 10:17 PM CDT for 34 counties in Oklahoma; 4 counties in Texas. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Sep 17, 2011, 10:17 PM CDT (03:17 UTC)
Expired
Sep 17, 2011, 11:45 PM CDT
In force
88 min
Issued by
the Storm Prediction Center
All 38 counties

Atoka County, OK, Bryan County, OK, Carter County, OK, Cherokee County, OK, Cleveland County, OK, Coal County, OK, Creek County, OK, Garvin County, OK, Haskell County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Latimer County, OK, Lincoln County, OK, Logan County, OK, Love County, OK, Marshall County, OK, McClain County, OK, McIntosh County, OK, Murray County, OK, Muskogee County, OK, Noble County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Tulsa County, OK, Wagoner County, OK, Cooke County, TX, Grayson County, TX, Montague County, TX, Wise County, TX

The radar

The Norman radar (KTLX), 101 km from the middle of the area, began a volume at 03:19 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 00:00Z, 3.3 hours before the alert went out and 105 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 00:00Z on 2011-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2097 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, Norman, OK at 00:00Z on 2011-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 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
2097 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
1371 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
234 m²/s²
Significant tornado parameter
0.9
Supercell composite
7.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

967 
ACUS11 KWNS 180318
SWOMCD
SPC MCD 180317
OKZ000-TXZ000-180445-

MESOSCALE DISCUSSION 2187
NWS STORM PREDICTION CENTER NORMAN OK
1017 PM CDT SAT SEP 17 2011

AREAS AFFECTED...NW TX INTO OK

CONCERNING...SEVERE THUNDERSTORM WATCH 850...851...

VALID 180317Z - 180445Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
850...851...CONTINUES.

STORMS OVER NRN OK MERGED INTO AN MCS...AND CONTINUE TO SURGE SEWD
INTO A MUCH COOLER AND MORE STABLE AIR MASS. A SLY LOW LEVEL JET IS
HELPING TO MAINTAIN AN ELEVATED FEED OF MOISTURE...WITH STORM CORES
THE STRONGEST ON THE WRN FRINGE OF THIS CLUSTER. LARGE HAIL WILL BE
POSSIBLE WITH THE WRN CELLS.

TO THE S...ISOLATED SEVERE STORMS PERSIST NEAR THE RED RIVER. THESE
STORMS WILL HAVE BETTER ACCESS TO THE WARM SECTOR AND MAY PERSIST
FOR A COUPLE HOURS WITH A LARGE HAIL THREAT.

OVERALL...THE SEVERE THREAT IS EXPECTED TO REMAIN ISOLATED WITH
MAINLY HAIL...AND THE WATCHES WILL BE ALLOWED TO EXPIRE AT 04Z.

..JEWELL.. 09/18/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...TSA...FWD...OUN...

LAT...LON   34169562 33259663 33179773 33509809 34759760 36439757
            36699597 36249523 35619475 35159504 34169562

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 2:45 PM CDTMesoscale DiscussionSPCAdair, Atoka, Cherokee, Craig, Delaware, Haskell and 14 more2 hr
Sep 18, 3:30 PM CDTSevere Thunderstorm WatchSPCAdair, Atoka, Bryan, Carter, Cherokee, Choctaw and 24 more8 hr
Sep 18, 3:59 PM CDTMesoscale DiscussionSPCLove31 min
Sep 18, 5:41 PM CDTSevere Thunderstorm WatchSPCMcCurtain7 hr
Sep 18, 6:48 PM CDTMesoscale DiscussionSPCAdair, Atoka, Bryan, Cherokee, Choctaw, Coal and 20 more57 min
Sep 18, 4:06 PM CDTSevere Thunderstorm WatchSPCAnderson, Bosque, Brown, Callahan, Coke, Coleman and 51 more9 hr
Sep 18, 6:18 PM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Comal, Edwards, Hays and 6 more57 min

Nearby

Mesoscale Discussions in Oklahoma, 2011Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011

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.