[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 120057
SWODY1
SPC AC 120056

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0756 PM CDT FRI AUG 11 2006

VALID 120100Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS NRN/CNTRL PLAINS...

...NRN/CNTRL PLAINS...

SCATTERED SUPERCELLS HAVE INCREASED IN AREAL COVERAGE AHEAD OF UPPER
TROUGH FROM SERN SASKATCHEWAN...SWD INTO NWRN SD...WITH MORE
ISOLATED ACTIVITY OVER NCNTRL NEB/SCNTRL SD.  EARLY EVENING
SOUNDINGS AND DIAGNOSTIC DATA EXHIBIT A DEEP MIXED BOUNDARY LAYER
ACROSS THE HIGH PLAINS TO THE WEST OF THE ONGOING
CONVECTION...THROUGH 550MB AT RAP...WITH SIGNIFICANT INSTABILITY
DOWNSTREAM ACROSS THE MOIST SECTOR...COINCIDENT WITH THUNDERSTORM
ACTIVITY.  WITH LOSS OF DAYTIME HEATING IT APPEARS BOUNDARY LAYER
WILL DECOUPLE AS CAP BEGINS TO STRENGTHEN THIS EVENING.  LLJ SHOULD
PROVE INSTRUMENTAL IN MAINTAINING OVERNIGHT CONVECTION...ESPECIALLY
ACROSS ND.  GIVEN THE POSITION OF THE UPPER TROUGH...WELL UPSTREAM
OVER THE NRN ROCKIES...IT APPEARS LOW LEVEL WARM ADVECTION WILL AID
CONVECTIVE CLUSTERING AND POSSIBLE MCS DEVELOPMENT THAT SHOULD SHIFT
EWD TOWARD THE RED RIVER REGION OF NWRN MN BY THE END OF THE PERIOD.
 LARGE HAIL AND DAMAGING WINDS MAY ACCOMPANY THESE STORMS THROUGH
THE OVERNIGHT HOURS.

FARTHER SOUTH...LBS SOUNDING AT 00Z DISPLAYED A SIGNIFICANT AMOUNT
OF INSTABILITY THIS EVENING...MLCAPE IN EXCESS OF 2200 J/KG.  SEVERE
SUPERCELL STRUCTURES THAT ARE ONGOING ACROSS THIS REGION SHOULD
STRUGGLE TO SPREAD TOO FAR DOWNSTREAM GIVEN THE LACK OF LARGE SCALE
SUPPORT...AND EXPECTED FOCUS OF THE LLJ INTO THE NRN DAKOTAS.  WITH
LOSS OF HEATING CNTRL PLAINS CONVECTION SHOULD GRADUALLY BECOME
ELEVATED AND BACKBUILD INTO STEEPER HEAT PLUME BEFORE WEAKENING LATE
THIS EVENING.

..DARROW.. 08/12/2006