[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 112000
SWODY1
SPC AC 111959

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CST SAT MAR 11 2006

VALID 112000Z - 121200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ERN OK...AR...MO
AND IL...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...MS VALLEY...OH VALLEY AND UPPER MIDWEST...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN CA...

...MS VALLEY/SRN PLAINS...
WATER VAPOR IMAGERY CURRENTLY SHOWS SOUTHWEST FLOW IN PLACE ACROSS
THE REGION WITH A SHORTWAVE TROUGH IN OK. THIS FEATURE WILL FOCUS
LARGE-SCALE ASCENT AS IT MOVES NEWD ACROSS ERN OK...NW AR AND MO
LATE THIS AFTERNOON CAUSING STORM COVERAGE TO QUICKLY EXPAND. A
LARGE MCS ASSOCIATED WITH WIDESPREAD SEVERE WEATHER SHOULD GRADUALLY
DEVELOP THIS AFTERNOON AND EVENING ACROSS THE REGION.

OBJECTIVE ANALYSIS CURRENTLY SHOWS A BROAD WARM SECTOR EXISTS ACROSS
THE ERN PART OF THE SRN PLAINS EXTENDING NNEWD ACROSS THE OZARK
PLATEAU AND LOWER TO MID MS VALLEY. THE AIRMASS IS CHARACTERIZED BY
MODERATE INSTABILITY WITH 0-6 KM SHEAR VALUES GENERALLY RANGING FROM
50 KT ACROSS THE OZARK PLATEAU TO 70 KT ACROSS THE OH VALLEY. THIS
SUGGESTS SUPERCELLS WILL BE LIKELY WITH STORMS THAT REMAIN DISCRETE.
AS STORM COVERAGE EXPANDS THROUGH EARLY EVENING...BOW ECHOES AND
MULTICELLS WILL BECOME LIKELY WITH LINEAR STORM CLUSTERS. THE
GREATEST SEVERE WEATHER THREAT LATE THIS AFTERNOON WILL LIKELY BE
ACROSS MO...ERN OK...WRN AR AND NE TX WHERE FORECAST SOUNDINGS
SUGGEST LAPSE RATES WILL STEEPEN OVER THE NEXT FEW HOURS. THE
MODERATE INSTABILITY AND VERY STRONG VERTICAL SHEAR SHOULD BE
SUFFICIENT FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL. IN
ADDITION...THE TORNADO THREAT WILL INCREASE THROUGH EARLY THIS
EVENING AS THE LOW-LEVEL JET STRENGTHENS AND THE LOW-LEVEL SHEAR
BECOMES MORE FAVORABLE. A THREAT FOR TORNADOES AND WIND DAMAGE WILL
EXPAND EWD AS A LARGE LINEAR MCS DEVELOPS THIS EVENING AND MOVES
ACROSS MO...IL AND WRN AR. A FEW SIGNIFICANT TORNADOES WILL BE
POSSIBLE WITH SUPERCELLS AND/OR WITH THE STRONGER BOW ECHOES
EMBEDDED IN OR AHEAD OF THE LINE. THE GREATEST TORNADO THREAT SHOULD
BE IN THE 00Z TO 06Z TIMEFRAME EXTENDING NEWD FROM NRN AR ACROSS
CNTRL AND ERN MO INTO THE ST. LOUIS AREA. THE BROAD WARM SECTOR
SUGGESTS A SEVERE WEATHER THREAT WILL CONTINUE WITH THE LINEAR MCS
AS IT MOVES EWD INTO THE OH VALLEY AND NEARS THE MS RIVER LATE
TONIGHT.

...CALIFORNIA...
WATER VAPOR IMAGERY CURRENTLY SHOWS AN UPPER-LEVEL LOW NEAR THE ORE
COAST WITH A TROUGH EXTENDING SSEWD ALONG THE CA COAST. LARGE-SCALE
ASCENT WITH THE TROUGH WILL MAKE THUNDERSTORM DEVELOPMENT POSSIBLE
THIS AFTERNOON FROM THE SACRAMENTO VALLEY TO THE LA BASIN. FORECAST
SOUNDINGS ALONG THIS CORRIDOR LATE THIS AFTERNOON SHOW STEEP
MID-LEVEL LAPSE RATES WITH 500 MB TEMPS FROM -30 TO -35 C. THIS
SUGGESTS LARGE HAIL WILL BE POSSIBLE WITH THE STRONGER CELLS.
MINI-SUPERCELLS WITH A BRIEF TORNADO THREAT WILL BE MOST LIKELY
ACROSS SRN CA WHERE OBJECTIVE ANALYSIS SHOWS 0-6 KM SHEAR VALUES
EXCEEDING 40 KT. THE SEVERE WEATHER THREAT SHOULD DIMINISH THIS
EVENING AS INSTABILITY DECREASES.

..BROYLES.. 03/11/2006