[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 060106
SWODY1
SPC AC 060104

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0804 PM CDT SAT AUG 05 2006

VALID 060100Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLAINS
AND UPPER MS VALLEY...

...ERN DAKOTAS AND MN...
POTENT MID-UPPER LEVEL DISTURBANCE WAS CLEARLY EVIDENT ON WATER
VAPOR IMAGERY ACROSS SRN MANITOBA AND NRN ND THIS EVENING. DIFFLUENT
MID LEVEL FLOW FIELD AHEAD OF THIS IMPULSE WAS AIDING DEEP LAYER
ASCENT ALONG AN ADVANCING ASSOCIATED COLD FRONT FROM NRN MN SWWD
INTO NCNTRL SD. STRONGEST DYNAMIC FORCING ASSOCIATED WITH THE MID
LEVEL SYSTEM WILL CONTINUE TO TRAVEL ACROSS NRN MN THROUGH TONIGHT
WHILE SOMEWHAT WEAKER LARGE SCALE FORCING WILL ACCOMPANY THE FRONTAL
PASSAGE FROM ERN SD ACROSS SRN MN AND NRN IA THROUGH EARLY SUNDAY.

A FEW INTENSE SUPERCELLS HAVE DEVELOPED AHEAD OF THE FRONT... ACROSS
ERN ND AND NRN MN...WHERE DYNAMIC FORCING HAS ACTED TO LOCALLY
OVERCOME STRONG CONVECTIVE INHIBITION. THIS ACTIVITY APPEARS TO HAVE
RECENTLY INCREASED IN COVERAGE AND INTENSITY AS IT MOVES INTO AN
INSTABILITY AXIS WHERE PRONOUNCED SPEED AND DIRECTIONAL SHEAR WILL
CONTINUE TO SUPPORT UPDRAFT ROTATION AND STORM PERSISTENCE.
DIAGNOSTIC DATA CONTINUE TO SUGGEST THAT BOTH VERY LARGE HAIL AND
ISOLATED TORNADOES WILL BE POSSIBLE WITH THESE CELLS AS THEY TRACK
ACROSS PARTS OF SERN ND AND NWRN/NRN MN THIS EVENING.

FARTHER SOUTH AND EAST...MSP SOUNDING DEPICTED PRONOUNCED WARM LAYER
ABOVE 800 MB CONTRIBUTING TO SIGNIFICANT INHIBITION...WHICH LIKELY
COVERS MUCH OF THE WARM SECTOR AHEAD OF THE FRONT. A CLUSTER OF
POORLY ORGANIZED STORMS ON THE SRN FRINGE OF STRONGER DEEP LAYER
SHEAR PERSISTS FROM NERN NEB INTO EXTREME SERN SD. THIS ACTIVITY
INITIATED EARLIER ON THE APEX OF SURFACE THERMAL RIDGE AXIS/TROUGH
WHERE DEEP MIXING IN VERY HOT AIR MASS WAS SUFFICIENT TO OVERCOME
CONVECTIVE INHIBITION /SEE OAX EVENING RAOB/. MEANWHILE...ISOLATED
STORM UPDRAFTS HAVE STRUGGLED TO TAKE ROOT ALONG THE FRONTAL WIND
SHIFT OVER CNTRL/NERN SD.

OVERNIGHT EVOLUTION OF CONVECTION ACROSS THESE AREAS...EWD ACROSS
IA/SRN MN...REMAINS UNCERTAIN. CURRENT ACTIVITY SHOULD CONTINUE TO
POSE A THREAT OF ISOLATED WIND AND HAIL. LATEST NAM-WRF AND RUC
DEPICT DIFFERING SOLUTIONS WITH THE NAM-WRF DEVELOPING AN MCS ACROSS
IA...AND RUC KEEPING STRONGER UVV AND QPF SIGNALS FARTHER
NORTH...ACROSS MN. IT SEEMS POSSIBLE THAT A SEVERE MCS MAY DEVELOP
ACROSS NRN IA/SRN MN LATER TONIGHT AS FRONTAL LIFT MOVES SEWD INTO
VERY MOIST AND UNSTABLE AIR MASS...AND MASS TRANSPORT INTO THE
REGION IS MAXIMIZED ON THE NOSE OF PLAINS LOW LEVEL JET.

...SOUTHEAST...
POCKETS OF STRONG INSTABILITY REMAIN SITUATED AHEAD OF SCATTERED
CLUSTERS OF PERSISTENT CONVECTION FROM LA EWD TO SC LATE THIS
EVENING. CELL MERGERS AND LIFT ALONG COMPOSITE OUTFLOWS MAY BE
SUFFICIENT FOR A FEW ROBUST UPDRAFTS...AND POSSIBLY LEAD TO NEW
DEVELOPMENT...OVER THE NEXT COUPLE OF HOURS. ISOLATED WET DOWNBURSTS
PRODUCING DAMAGING WINDS APPEAR TO BE THE MAIN HAZARD UNTIL BOUNDARY
LAYER STABILIZES FURTHER.

..CARBIN.. 08/06/2006