Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 1776

August 16, 201221 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Aug 16, 2012, 4:45 PM CDT for 21 counties in Oklahoma. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 16, 2012, 4:45 PM CDT (21:45 UTC)
Expired
Aug 16, 2012, 6:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 21 counties

Beckham County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Creek County, OK, Grady County, OK, Greer County, OK, Kiowa County, OK, Lincoln County, OK, McClain County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Tulsa County, OK, Wagoner County, OK, Washita County, OK

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 9.8 hours before the alert went out and 43 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 2012-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1741 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 2012-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 155 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
1741 J/kg
Mixed-layer CIN
-210 J/kg
Mixed-layer LCL
1469 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
155 m²/s²
0-3 km storm-relative helicity
195 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

400 
ACUS11 KWNS 162146
SWOMCD
SPC MCD 162145
OKZ000-162345-

MESOSCALE DISCUSSION 1776
NWS STORM PREDICTION CENTER NORMAN OK
0445 PM CDT THU AUG 16 2012

AREAS AFFECTED...PARTS OF OKLAHOMA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 162145Z - 162345Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED STORMS CAPABLE OF PRODUCING SVR WIND GUSTS MAY
DEVELOP INVOF A NE-SW-ORIENTED FRONT THAT BISECTS OKLAHOMA. LIMITED
STORM ORGANIZATION AND COVERAGE SHOULD PRECLUDE THE NEED FOR A WW.

DISCUSSION...VISIBLE SATELLITE IMAGES INDICATE A BROAD ZONE OF
BOUNDARY-LAYER CUMULUS COLOCATED WITH A FRONT LYING NEAR/NORTH OF
THE I-44 CORRIDOR. MODIFIED 12Z NORMAN AND 17Z LAMONT SOUNDINGS TO
ACCOUNT FOR SFC CONDITIONS NEAR/SOUTH OF THE FRONT SUGGEST AROUND
20-50 J/KG OF INHIBITION REMAIN WITH MLCAPE OF 500-1500 J/KG.
SUFFICIENT FRONTAL ASCENT MAY SUPPORT THE DEVELOPMENT OF A FEW
STORMS DURING THE NEXT COUPLE OF HOURS. SHOULD STORMS FORM...SFC
DEWPOINT DEPRESSIONS AOA 30F AND MODEST MID-LEVEL DRY AIR SHOULD
SUPPORT A CONDITIONAL THREAT FOR MICROBURSTS CAPABLE OF SVR WIND
GUSTS. HOWEVER...RELATIVELY WEAK FRONTAL CONVERGENCE WOULD SUGGEST
STORM COVERAGE SHOULD BE LIMITED...AND AROUND 10-15 KT OF 0-6-KM
BULK SHEAR PER TWIN LAKES VWP DATA INDICATES A PULSE CONVECTIVE MODE
WILL PREDOMINATE. WHILE THE THREAT FOR STORMS MAY SPREAD SWD IN
ASSOCIATION WITH THE MOTION OF THE FRONT...THE SRN EXTENT OF THE SVR
THREAT WILL BE MODULATED BY WEAK LOW-LEVEL LAPSE RATES OFFERED BY
MULTI-LAYERED CLOUDS ACROSS SRN OK.

..COHEN/THOMPSON.. 08/16/2012

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

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

LAT...LON   35469971 35519923 35599865 35679802 35889738 36189672
            36509607 36559568 36199526 35879507 35579505 35299562
            35069659 34889769 34709925 34839974 35019992 35269996
            35469971

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 16, 1:26 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Delaware, Haskell, LeFlore, McIntosh and 5 more64 min

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.