Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 1995

September 26, 201213 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Sep 26, 2012, 8:08 PM CDT for 13 counties in Oklahoma. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Sep 26, 2012, 8:08 PM CDT (01:08 UTC)
Expired
Sep 26, 2012, 9:45 PM CDT
In force
97 min
Issued by
the Storm Prediction Center

Counties Creek County, OK, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, Lincoln County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pottawatomie County, OK, Seminole County, OK

The radar

The Tulsa radar (KINX), 118 km from the middle of the area, began a volume at 01:12 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, 1.1 hours before the alert went out and 153 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 2012-09-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2226 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 2012-09-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 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
2226 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
1605 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.3
Supercell composite
5.1

Open this sounding in Storm Lab

The text

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

430 
ACUS11 KWNS 270109
SWOMCD
SPC MCD 270108
OKZ000-270245-

MESOSCALE DISCUSSION 1995
NWS STORM PREDICTION CENTER NORMAN OK
0808 PM CDT WED SEP 26 2012

AREAS AFFECTED...CENTRAL AND EAST-CENTRAL OK

CONCERNING...SEVERE THUNDERSTORM WATCH 651...

VALID 270108Z - 270245Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 651
CONTINUES.

SUMMARY...ISOLATED TSTMS WILL CONTINUE TO POSE A THREAT FOR STRONG
WINDS AND/OR HAIL ACROSS THE VALID PORTION OF WW 651.  WHILE THE
POTENTIAL EXISTS FOR TSTMS TO PERSIST THROUGH THE EVENING...THE
OVERALL SVR WEATHER THREAT IS NOT EXPECTED TO INCREASE SUCH THAT A
NEW WW IS NOT WARRANTED BEYOND THE 03Z EXPIRATION.

DISCUSSION...SURFACE OBSERVATIONS AND TRENDS IN SATELLITE/RADAR
IMAGERY INDICATED AN OUTFLOW BOUNDARY ATTENDANT TO THE ONGOING
CLUSTER OF TSTMS IN EAST CENTRAL OK HAS CONTINUED TO SPREAD
WWD...AND AT 01Z THIS FEATURE EXTENDED SWD FROM NRN LOGAN COUNTY /30
SE END/ TO 15 SE OKC TO 35 NNW ADM TO 35 NNE DUA.  WEAK SSWLY LOW
LEVEL WINDS PER 00Z OUN SOUNDING AND 00Z PURCELL WIND PROFILER
SUGGEST WEAK WAA E OF THE OUTFLOW BOUNDARY SHOULD SUPPORT ADDITIONAL
TSTM DEVELOPMENT.  TRENDS IN OBJECTIVE ANALYSES INDICATED GRADUAL
WEAKENING OF CONVECTIVE INSTABILITY AS THE BOUNDARY LAYER COOLS
GIVEN TIME OF DAY...THOUGH RESIDUAL INSTABILITY DURING THE NEXT 1-3
HOURS COMBINED WITH EFFECTIVE BULK SHEAR OF 30-35 KT SUGGEST A FEW
STRONG TO SVR STORMS REMAIN POSSIBLE.

..PETERS.. 09/27/2012

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

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

LAT...LON   34519455 34529596 34899724 35939718 35929632 35629534
            35079459 34519455

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 26, 7:17 PM CDTMesoscale DiscussionSPCAlfalfa, Beckham, Blaine, Caddo, Canadian, Comanche and 19 more58 min
Sep 26, 10:29 PM CDTMesoscale DiscussionSPCBeaver, Ellis, Harper, Woodward61 min
Sep 27, 3:09 PM CDTMesoscale DiscussionSPCCimarron66 min
Sep 27, 5:59 PM CDTSevere Thunderstorm WatchSPCCimarron, Texas7 hr

Nearby

Mesoscale Discussions in Oklahoma, 2012Every mesoscale discussion in 2012

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.