Alert archive / Oklahoma / Mesoscale Discussions in 2011

Mesoscale Discussion 2186

September 17, 2011Barber County, Harper County, Kansas; 22 counties in Oklahoma; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 17, 2011, 5:49 PM CDT for Barber County, Harper County, Kansas; 22 counties in Oklahoma; 6 counties in Texas. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
Sep 17, 2011, 5:49 PM CDT (22:49 UTC)
Expired
Sep 17, 2011, 7:45 PM CDT
In force
116 min
Issued by
the Storm Prediction Center
All 30 counties

Barber County, KS, Harper County, KS, Alfalfa County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Grant County, OK, Kay County, OK, Kingfisher County, OK, Kiowa County, OK, Logan County, OK, Major County, OK, Noble County, OK, Pawnee County, OK, Payne County, OK, Tillman County, OK, Washita County, OK, Woods County, OK, Woodward County, OK, Archer County, TX, Baylor County, TX, Shackelford County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 93 km from the middle of the area, began a volume at 22:51 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, 10.8 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 12:00Z on 2011-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 71 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 12:00Z on 2011-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 388 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
71 J/kg
Mixed-layer CIN
-349 J/kg
Mixed-layer LCL
833 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
388 m²/s²
0-3 km storm-relative helicity
458 m²/s²
Significant tornado parameter
0.0
Supercell composite
13.0

Open this sounding in Storm Lab

The text

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

383 
ACUS11 KWNS 172250
SWOMCD
SPC MCD 172249
OKZ000-KSZ000-TXZ000-180045-

MESOSCALE DISCUSSION 2186
NWS STORM PREDICTION CENTER NORMAN OK
0549 PM CDT SAT SEP 17 2011

AREAS AFFECTED...NW TX...WRN  AND NRN OK...S CNTRL KS

CONCERNING...TORNADO WATCH 850...851...

VALID 172249Z - 180045Z

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

STORMS HAVE INTENSIFIED DURING PEAK HEATING WITH STEEP LAPSE RATES
NEAR THE DRYLINE. HELPING TO ENHANCE CONVERGENCE IS A WEAK UPPER
VORT MOVING EWD ACROSS SRN KS/NRN OK. FORCING IS CURRENTLY MAXIMIZED
WHERE THESE FEATURES INTERSECT THE WARM FRONT ACROSS NRN OK WHERE A
POTENTIALLY TORNADIC STORM WAS ONGOING.

AMPLE MOISTURE AND INSTABILITY WILL CONTINUE TO FUEL STRONG UPDRAFTS
NEAR THE DRYLINE AND WARM FRONT. STORM MOTIONS WILL CONTINUE TO BE
RELATIVELY SLOW OWING TO MARGINAL FLOW ALOFT...BUT VEERING WINDS
WITH HEIGHT IN THE LOWEST FEW KM WILL CONTINUE TO BE SUFFICIENT FOR
SUPERCELL STRUCTURES...CAPABLE OF LARGE HAIL.

WITH TIME...CELLS OVER NWRN OK...WHERE STRONGER WIND FIELDS
EXIST...MAY MERGE INTO A CLUSTER OR SMALL MCS...CONTINUING EWD WITH
A DAMAGING WIND AND HAIL THREAT. IT IS POSSIBLE THAT PORTIONS OF
NERN OK AND/OR SERN KS MAY NEED TO BE ADDRESSED LATER THIS EVENING.

..JEWELL.. 09/17/2011

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

ATTN...WFO...TSA...ICT...FWD...OUN...DDC...SJT...

LAT...LON   32769976 33699937 35209920 36149940 36909950 37409876
            37199761 36639671 36059637 35899749 34879815 33559856
            32719900 32769976

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 2:02 PM CDTMesoscale DiscussionSPCBarber, Clark, Comanche, Ford, Harper, Kingman and 3 more88 min
Sep 17, 2:30 PM CDTTornado WatchSPCBarber, Chautauqua, Clark, Comanche, Cowley, Edwards and 14 more9 hr
Sep 17, 4:49 PM CDTMesoscale DiscussionSPCSherman56 min
Sep 17, 2:38 PM CDTMesoscale DiscussionSPCBeckham, Caddo, Comanche, Cotton, Greer, Harmon and 6 more97 min
Sep 17, 3:16 PM CDTSevere Thunderstorm WatchSPCBeckham, Caddo, Canadian, Comanche, Cotton, Custer and 10 more8 hr

Nearby

Mesoscale Discussions in Oklahoma, 2011Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Kansas, 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.