[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 282001
SWODY1
SPC AC 281959

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CST TUE FEB 28 2006

VALID 282000Z - 011200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
SYNOPTIC PATTERN REMAINS CHARACTERIZED BY CENTRAL CONUS
RIDGING...AND PRONOUNCED TROUGH FROM ERN GULF OF AK SWD OFFSHORE CA.

PRIMARY MIDLEVEL SHORTWAVE PERTURBATION IS EVIDENT IN MOISTURE
CHANNEL AND VIS IMAGERY AS SWIRL INVOF CAPE MENDOCINO. THIS
FEATURE...AND ACCOMPANYING SHORTWAVE TROUGH...SHOULD MOVE ACROSS NRN
CA TOWARD SWRN ORE AND NWRN NV THROUGH TONIGHT.

...NRN CA...
PRIMARY BROKEN BAND OF TSTMS -- WHICH HAS INCLUDED A FEW SMALL
SUPERCELLS -- IS EVIDENT ATTM IN VIS AND REFLECTIVITY IMAGERY FROM
SIERRAN FOOTHILLS ESE SAC...SWWD TO NRN FRINGES OF MRY BAY.  AS NRN
END OF THIS ACTIVITY DIMINISHES UPON PENETRATION OF MORE
ELEVATED/COOLER TERRAIN...MARGINAL SEVERE POTENTIAL WILL SHIFT SEWD
THROUGH CENTRAL VALLEY FROM MOD AREA ALMOST TO FAT.  EXPECT MIDLEVEL
COOLING -- PRODUCED BY LARGE SCALE ASCENT AHEAD OF LAND FALLING
SHORTWAVE PERTURBATION -- TO JUXTAPOSE VERTICALLY WITH OPTIMAL
DIABATIC SFC HEATING.  RESULTING BOOST IN LOW-MIDLEVEL LAPSE RATES
SHOULD COMBINE WITH MID/UPPER 40S F SFC DEW POINTS TO YIELD MLCAPES
200-300 J/KG AND MUCAPES TOPPING 500 J/KG...PER MODIFIED RUC
SOUNDINGS.  PRE-STORM VWP FROM SAC AREA INDICATED FAVORABLE LOW
LEVEL SHEAR...AUGMENTED BY OROGRAPHICALLY FORCED BACKING OF SFC
WINDS. VEERING/WEAKENING OF LOW LEVEL FLOW...WITH ATTENDANT
REDUCTION IN BOTH SHEAR AND CONVERGENCE...IS EXPECTED AFTER PASSAGE
OF PRIMARY CONVECTIVE BAND...THOUGH SMALL HAIL WILL REMAIN POSSIBLE
FROM MORE ISOLATED ACTIVITY FARTHER N.

...GREAT BASIN...
WIDELY SCATTERED/HIGH-BASED TSTMS REMAIN POSSIBLE AS BAROCLINICALLY
ENHANCED CONVECTIVE BAND NOW OVER CENTRAL/NERN NV SHIFTS EWD THIS
AFTERNOON.  ADDITIONAL...MORE ISOLATED DEVELOPMENT ALSO MAY OCCUR
AHEAD OF AFOREMENTIONED BAND.  CONTINUED SFC HEATING OF RELATIVELY
LOW DEW POINT BOUNDARY LAYERS MAY RESULT IN ENHANCED POTENTIAL FOR
GUSTS NEAR SEVERE LIMITS...AS WELL AS POTENTIAL FOR SUBSEVERE
CONVECTIVE GUSTS SUPERIMPOSED ON STRONG GRADIENT FLOW TO YIELD
DAMAGING WIND.

..EDWARDS.. 02/28/2006