[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 120544
SWODY1
SPC AC 120542

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1242 AM CDT SAT AUG 12 2006

VALID 121200Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NRN/CNTRL PLAINS
INTO THE UPPER MS VALLEY...

HEIGHT FALLS ACROSS THE NRN ROCKIES WILL FLATTEN THE RIDGE IN PLACE
ACROSS THE NRN PLAINS LATER TODAY.  AS UPPER TROUGH SHIFTS EWD
ACROSS ID/MT IT SHOULD FORCE A WEAK DISTURBANCE LOCATED OVER UT NEWD
INTO SD BY 00Z...ENHANCING DEEP LAYER SHEAR ALONG AN ELONGATED ZONE
OF TIGHTENING LOW LEVEL CONFLUENCE FROM THE NEB PANHANDLE INTO ERN
ND/NWRN MN.  THIS LOW LEVEL BOUNDARY WILL SERVE AS THE FOCUS FOR
EPISODIC CONVECTIVE EVENTS DURING THE DAY1 PERIOD.

LATEST THINKING IS SCATTERED THUNDERSTORM ACTIVITY WILL BE ONGOING
EARLY IN THE PERIOD WITHIN WARM ADVECTION ZONE ACROSS THE ERN
DAKOTAS/MN AS LLJ FEEDS ONGOING ELEVATED CONVECTION.  ALTHOUGH THIS
ACTIVITY MAY PRODUCE ISOLATED HAIL OR GUSTY WINDS...IT APPEARS
STRONGER ACTIVITY WILL EVOLVE LATER IN THE DAY AS BOUNDARY LAYER
HEATS ALONG WIND SHIFT.  FAVORABLE LOW LEVEL TRAJECTORIES WILL
MAINTAIN MORE THAN SUFFICIENT MOISTURE ACROSS THE NRN/CNTRL PLAINS
FOR RENEWED THUNDERSTORM DEVELOPMENT BY 21Z...ESPECIALLY GIVEN THE
ADDED ASCENT AHEAD OF EJECTING CNTRL ROCKIES SHORTWAVE TROUGH. WITH
STRENGTHENING VERTICAL SHEAR PROFILES IT APPEARS SUPERCELL
STRUCTURES ARE POSSIBLE...ESPECIALLY EARLY IN THE AFTERNOON
CONVECTIVE CYCLE.  THE ENTIRE FRONTAL ZONE MAY CONVECT QUICKLY AND
EXPAND LINEARLY NEWD  FROM CO INTO MN BY 00Z.  LATEST FORECAST
SOUNDINGS SUGGEST AN ENHANCED SUPERCELL THREAT MAY EXIST AHEAD OF
WEAK SFC LOW FROM ERN SD INTO WCNTRL MN BETWEEN 21Z-03Z.  THIS SFC
FEATURE APPEARS CORRELATED WITH EJECTING SHORTWAVE WHICH COULD
RESULT IN A FEW TORNADOES BEFORE STORM MERGERS AND MULTI-CELL
CLUSTERS BECOME DOMINATE.  OTHERWISE...SUFFICIENT
MOISTURE/INSTABILITY WILL LINGER WITHIN POST FRONTAL REGIME ACROSS
THE NRN PLAINS FOR AN ELEVATED ANA-TYPE CONVECTIVE EVENT TO DEVELOP
ACROSS PORTIONS OF SD/ND LATER IN THE EVENING HOURS...AIDED BY MAIN
UPPER TROUGH THAT APPROACHES AFTER DARK.  LARGE HAIL SHOULD BE THE
PRIMARY SEVERE RISK ACROSS THE SLIGHT RISK REGION.

...ELSEWHERE...

STATIONARY...DECAYING FRONTAL ZONE FROM GA...WWD ACROSS THE NRN GULF
STATES INTO THE SRN PLAINS WILL FOCUS CONVECTION AGAIN TODAY.  VERY
MOIST PROFILES AND WEAK TROPOSPHERIC FLOW MAY ENHANCE LOCAL WET
MICROBURSTS...HOWEVER ORGANIZED DAMAGING WIND THREAT WILL PROVE TOO
DIFFICULT TO PREDICT THIS EARLY IN THE CONVECTIVE PERIOD.

..DARROW/TAYLOR.. 08/12/2006