[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 171732
SWODY2
SPC AC 171731

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1231 PM CDT THU AUG 17 2006

VALID 181200Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY REGION
EWD INTO THE MIDWEST/OH VALLEY...

...SYNOPSIS...
LARGE UPPER RIDGE WILL PREVAIL ACROSS MUCH OF THE ERN 2/3 OF THE
CONUS...WHILE MAIN SHORT-WAVE TROUGH MOVES EWD FROM THE NRN ROCKIES
INTO THE NRN PLAINS ALONG NRN PERIPHERY OF RIDGE. 
ADDITIONALLY...SEVERAL SMALLER-SCALE VORTICITY MAXIMA ARE EXPECTED
TO SHIFT EWD ACROSS THE PLAINS/MIDWEST...AHEAD OF MAIN SHORT-WAVE
TROUGH.

AT THE SURFACE...COLD FRONT INITIALLY FORECAST FROM THE UPPER GREAT
LAKES INTO THE CENTRAL ROCKIES IS EXPECTED TO WEAKEN WITH TIME AS IT
SHIFTS EWD/SEWD.  RESULTING SURFACE PATTERN SHOULD BECOME
INCREASINGLY ILL-DEFINED...EXTENDING FROM THE PLAINS EWD INTO THE
MIDWEST/OH VALLEY REGION. 

...MID MO/MID MS VALLEY REGIONS INTO THE OH VALLEY...
LARGE AREA OF WEAK WARM ADVECTION IS FORECAST ACROSS THIS
REGION...AS UPPER HEIGHTS FALL AHEAD OF ADVANCING SHORT-WAVE TROUGH.
 SEVERAL CLUSTERS OF CONVECTION SHOULD BE ONGOING AT THE START OF
THE PERIOD...WHICH COMBINED WITH THE INCREASINGLY ILL-DEFINED
SURFACE PATTERN SUGGEST A RATHER COMPLEX SEVERE WEATHER FORECAST.

IN GENERAL...SUFFICIENT INSTABILITY AND MARGINAL SHEAR ARE
ANTICIPATED INVOF BAROCLINIC ZONE...WHILE STRONGER SHEAR REMAINS N
OF THE WARM SECTOR WITHIN THE COOLER AIR AND CAPPING INVERSION
PREVAILS WITHIN WARM SECTOR AWAY FROM SURFACE BOUNDARIES.  GREATEST
THREAT APPEARS TO EXIST ACROSS THE MID MO VALLEY REGION...AS
LOW-LEVEL CONVERGENCE INCREASES AHEAD OF APPROACHING SHORT-WAVE
FEATURE DURING THE AFTERNOON.  EXPECT STORMS TO DEVELOP INVOF
WEAKENING SURFACE BOUNDARY -- AND PERHAPS ALONG REMNANT
OUTFLOWS...WHERE SUFFICIENT INSTABILITY BUT MARGINAL SHEAR SUGGEST
MULTICELL/WEAK SUPERCELL STORMS CAPABLE OF HAIL AND/OR
LOCALLY-DAMAGING WINDS.  LESSER SEVERE THREAT SHOULD EXTEND EWD INTO
THE MIDWEST/OH VALLEY...WHERE WEAKER SHEAR IS FORECAST ALONG REMNANT
WARM FRONT/BAROCLINIC ZONE.  OVERNIGHT...MODEST SWLY LOW-LEVEL JET
IS FORECAST TO DEVELOP ACROSS MO AND VICINITY...WHICH SHOULD SUPPORT
A CONTINUATION OF CONVECTION -- LIKELY IN THE FORM OF ONE OR MORE
MCS.  OVERALL HOWEVER...DIURNALLY-STABILIZING AIRMASS SUGGESTS A
SLOWLY DECREASING SEVERE THREAT THROUGH THE END OF THE PERIOD.

..GOSS.. 08/17/2006