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000
ACUS01 KWNS 151250
SWODY1
SPC AC 151248

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0748 AM CDT SAT JUN 15 2013

VALID 151300Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HIGH PLAINS TO
THE MIDWEST...

...SYNOPSIS...

THE LARGE-SCALE FLOW REGIME WILL BECOME INCREASINGLY ZONAL THIS
PERIOD TO THE SOUTH OF A HIGH-LATITUDE BLOCKING PATTERN WHICH
STRETCHES FROM THE NERN PACIFIC TO ERN CANADA.  A SHORT-WAVE TROUGH
CURRENTLY ROUNDING THE BASE OF AN UPPER-LEVEL LOW OVER SK WILL SHEAR
EWD WITHIN A MIDLEVEL CONFLUENCE ZONE OVER THE UPPER MIDWEST AND
UPPER GREAT LAKES.  MEANWHILE...A LOWER-LATITUDE TROUGH FROM CNTRL
KS TO CNTRL TX WILL DEAMPLIFY WHILE PROGRESSING NEWD INTO THE MID-MS
VALLEY AND OZARK PLATEAU.

IN THE LOW LEVELS...THE NRN SEGMENT OF A COLD FRONT INITIALLY FROM
THE UPPER-MS VALLEY SWWD TO CNTRL HIGH PLAINS WILL ADVANCE EWD INTO
THE UPPER GREAT LAKES WHILE THE TRAILING PORTION DECELERATES OVER
ERN CO/WRN KS.  THIS FRONT ALONG WITH A CONVECTIVE OUTFLOW BOUNDARY
OVER THE LOWER-MO VALLEY WILL LIKELY SERVE AS THE FOCI FOR STRONG TO
SEVERE TSTM DEVELOPMENT LATER TODAY INTO TONIGHT.

...MID/LOWER-MO VALLEY INTO MIDWEST TODAY INTO THIS EVENING...

CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD TO CONVECTIVE EVOLUTION
OWING TO THE PRESENCE OF ONGOING STORMS...A WIDE VARIETY OF MODEL
SOLUTIONS...AND A RECENTLY OVERTURNED AIR MASS ACROSS PARTS OF
IA/NRN MO BY A NOW-DECAYING...NOCTURNAL MCS.  AS MENTIONED IN THE
SYNOPSIS...IT APPEARS THAT THE SYNOPTIC COLD FRONT AND A COMPOSITE
WARM FRONT-OUTFLOW BOUNDARY OVER THE LOWER-MO/MID-MS VALLEY REGION
WILL FOCUS THE MOST INTENSE STORMS WHERE A RISK FOR DAMAGING WINDS
AND HAIL WILL EXIST.  THE INITIAL SEVERE THREAT MAY MATERIALIZE THIS
MORNING OVER THE MID-MO VALLEY AS DISCUSSED IN MCD 1087.

THE STRONGEST AIR MASS DESTABILIZATION WILL LIKELY OCCUR ALONG THE
LOWER-MO VALLEY COMPOSITE BOUNDARY WHERE AFTERNOON MLCAPE VALUES
WILL APPROACH 2000-3500 J/KG.  THIS INSTABILITY WILL COINCIDE WITH A
CORRIDOR OF STRENGTHENING 700-500-MB WINDS...RESULTING IN MODERATELY
STRONG...DEEP WLY SHEAR.  AS SUCH...THE POTENTIAL WILL EXIST FOR
EMBEDDED SUPERCELL AND BOWING STRUCTURES CAPABLE OF A COUPLE OF
TORNADOES IN ADDITION TO THE DAMAGING WINDS AND HAIL.  SOME
POTENTIAL WILL EXIST FOR MERGING OF CONVECTIVE COMPLEXES AND AN
ENHANCED WIND THREAT OVER THE MIDWEST THIS EVENING.
HOWEVER...ENOUGH UNCERTAINTY IN THIS SCENARIO EXISTS SUCH THAT WIND
PROBABILITIES WILL NOT BE INCREASED IN THIS FORECAST.

...CNTRL HIGH PLAINS THIS AFTERNOON INTO TONIGHT...

MIDLEVEL HEIGHTS WILL RISE SLIGHTLY TODAY IN THE WAKE OF THE
MIGRATORY SHORT-WAVE TROUGH MOVING THROUGH THE NRN PLAINS AND UPPER
MS VALLEY.  NONETHELESS...ELY/SELY LOW-LEVEL FLOW INVOF DECELERATING
COLD FRONT WILL ENHANCE LIFT ALONG THE HIGH TERRAIN AND FOSTER
WIDELY SCATTERED TSTMS LATER THIS AFTERNOON INTO EVENING.  THE WWD
ADVECTION OF AN INCREASINGLY MOIST BOUNDARY LAYER BENEATH STEEP
MIDLEVEL LAPSE RATES WILL YIELD MODERATE AFTERNOON INSTABILITY WITH
MLCAPE VALUES OF 1500-2500 J/KG.  WHEN COUPLED WITH A VERTICALLY
VEERING WIND PROFILE WITH DEEP-LAYER SHEAR STRENGTHENING TO 45-50
KT...THE SETUP WILL BE QUITE FAVORABLE FOR SUPERCELLS CAPABLE OF
VERY LARGE HAIL AND PERHAPS A COUPLE OF TORNADOES.  STORMS MAY GROW
UPSCALE INTO AN MCS OVER WRN KS LATER THIS EVENING WHERE A RISK FOR
HAIL AND DAMAGING WINDS MAY PERSIST INTO THE OVERNIGHT HOURS.

...ERN OK INTO THE OZARKS TODAY INTO THIS EVENING...

THE 12Z OUN/SGF SOUNDINGS INDICATE THAT THE COMBINATION OF A MOIST
BOUNDARY LAYER AND RESIDUAL EML ALONG ERN PERIPHERY OF SUBTROPICAL
MIDLEVEL MOISTURE PLUME HAS RESULTED IN AN ALREADY MODERATELY TO
STRONGLY UNSTABLE ENVIRONMENT WITH MUCAPE OF 2000-4000+ J/KG AND
LITTLE OR NO CAP.  INCREASED FORCING ATTENDANT TO THE SHORT-WAVE
TROUGH WILL PROMOTE SCATTERED TO NUMEROUS TSTMS TODAY...A FEW OF
WHICH WILL BE CAPABLE OF HAIL AND LOCALLY DAMAGING WINDS GIVEN THE
DEGREE OF INSTABILITY.

..MEAD/COHEN.. 06/15/2013