[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 221957
SWODY1
SPC AC 221956

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT TUE AUG 22 2006

VALID 222000Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE DAKOTAS
AND CNTRL/SRN MN...

...DAKOTAS TO MN...
STRONG WARM AIR ADVECTION AND DESTABILIZATION WERE UNDERWAY BENEATH
STOUT WARM SECTOR CAPPING ACROSS SD ATTM. SURFACE WARM FRONT WAS
RECENTLY ANALYZED BISECTING SD FROM NW TO SE WITH LATEST DIAGNOSTIC
DATA INDICATING MLCAPE IN EXCESS OF 2000 J/KG ALONG AND SOUTH OF THE
FRONT. WHILE SUBTLE SHORT WAVE IMPULSE APPEARS TO BE DEVELOPING EAST
ACROSS ERN MT AND WRN DAKOTAS ATTM...IT REMAINS TO BE SEEN WHETHER
BACKGROUND ASCENT ASSOCIATED THIS FEATURE CAN OVERCOME MODEST AND
PERSISTENT WARM SECTOR INHIBITION. RECENT CU TRENDS ACROSS THE BLACK
HILLS SUGGEST AT LEAST ISOLATED HIGH TERRAIN DEVELOPMENT SHOULD
OCCUR OVER THE NEXT FEW HOURS AND...GIVEN INTENSE SURFACE HEATING
AND MIXING ACROSS THE BADLANDS...SOME OF THIS ACTIVITY MAY SURVIVE
AND SPREAD EAST WITH ATTENDANT WIND AND LARGE HAIL HAZARDS THROUGH
EARLY EVENING.

SEVERE STORM DEVELOPMENT APPEARS A BIT MORE CERTAIN NEAR AND NORTH
OF THE WARM FRONT...FROM NERN SD INTO SRN ND INTO THIS EVENING. AS
LOW LEVEL INHIBITION IS WEAKENED THROUGH PERSISTENT BOUNDARY LAYER
HEATING...AND MID LEVEL WARMING IS POTENTIALLY OFFSET BY WEAK LARGE
SCALE ASCENT...EXPECT CHANCES FOR CONVECTIVE INITIATION TO INCREASE.
STORMS DEVELOPING NORTH OF THE SURFACE WARM FRONT SHOULD REMAIN
ELEVATED. HOWEVER...PROXIMITY OF STRONG INSTABILITY AND MORE THAN
ADEQUATE EFFECTIVE BULK SHEAR WILL LEAD TO ROBUST UPDRAFTS AND
PERHAPS A COUPLE OF SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL. IF
CELLS CAN DEVELOP OR TRACK NEAR THE WARM FRONT AND TAP NEAR SURFACE
PARCELS...ISOLATED TORNADO AND DOWNBURST WIND THREATS COULD ENSUE.

MAJORITY OF GUIDANCE INDICATES THAT AN MCS SHOULD EVOLVE FROM
EVENING CONVECTION AND THIS SYSTEM WILL SPREAD EWD/ESEWD INTO MN
THROUGH THE NIGHT SUSTAINED IN PART BY STRONG MASS INFLOW ON THE
NOSE OF PLAINS LLJ. SEVERE WIND AND HAIL MAY ACCOMPANY THIS
CONVECTION WELL INTO THE NIGHT ACROSS WRN/CNTRL AND SRN MN.

...SOUTH/SOUTHEAST...
WIDESPREAD PULSE AND MULTICELL CONVECTION WAS UNDERWAY ALONG
RESIDUAL FRONTAL AND OUTFLOW BOUNDARIES...AND SEA AND GULF
BREEZES...FROM ERN NC SWWD TO LA/TX. ISOLATED WET DOWNBURST WINDS
MAY DEVELOP WITH THIS CONVECTION AS IT MOVES INTO POCKETS OF STRONG
LATE AFTERNOON INSTABILITY.

...SOUTHWEST...
WEAK MID LEVEL DISTURBANCE ROTATING AROUND WRN/SWRN EDGE OF
SUBTROPICAL HIGH WAS AIDING HIGH-TERRAIN TSTM DEVELOPMENT FROM SRN
CA TO NRN PARTS OF AZ. MUCH OF SRN AZ REMAINS SHROUDED BY DEEP LAYER
CLOUD COVER THAT WAS INHIBITING DESTABILIZATION ACROSS THESE AREAS.
EXPECT CHANCES FOR DOWNBURST WINDS TO INCREASE IN THE NEXT FEW HOURS
OVER AREAS THAT HAVE UNDERGONE STRONG HEATING... PRIMARILY FROM THE
HIGHER ELEVATIONS OF SRN CA AND SRN NV...ACROSS PARTS OF CNTRL AND
NRN AZ.

...SRN LWR MI...ERN GREAT LAKES...NORTHEAST...
COLD FRONT WAS MOVING INTO WARM AND WEAKLY UNSTABLE AIR MASS FROM
LOWER MI EWD ACROSS NRN NEW ENGLAND THIS AFTERNOON. A STORM OR TWO
ALONG THE ADVANCING BOUNDARY COULD BRIEFLY ATTAIN SEVERE LEVELS WITH
THE POTENTIAL FOR LOCALLY STRONG WIND GUSTS OR MARGINALLY SEVERE
HAIL.

..CARBIN.. 08/22/2006