SWODY1
SPC AC 281323
DAY 1 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0823 AM CDT SAT AUG 28 2010
VALID 281300Z - 291200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN RCKYS AND
ADJACENT HI PLNS...
...THERE IS A SLGT RISK OF SVR TSTMS ALONG THE CNTRL GULF CST...
CORRECTED TO ADD SMALL 5 PCT AREA TO CORRESPOND WITH GULF COAST SLGT
AREA.
...SYNOPSIS...
TROUGH WILL FURTHER AMPLIFY OVER THE WRN STATES THIS PERIOD AS
STRONG VORT MAX NOW ENTERING NRN CA CONTINUES SE AND PHASES WITH
EXISTING TROUGH OVER THE NRN INTERMOUNTAIN REGION. EWD MOTION OF
THE TROUGH WILL...HOWEVER...BE SLOW GIVEN CONTINUING PRESENCE OF
STRONG RIDGE IN THE EAST. FRONTAL ZONE ASSOCIATED WITH THE
TROUGH...NOW EXTENDING FROM THE NRN PLNS SW INTO CNTRL CA....SHOULD
BUCKLE OVER THE ERN GRT BASIN TODAY AS A SFC WAVE FORMS OVER NE
NV/SRN ID/NRN UT AHEAD OF CA VORT. THIS WAVE SHOULD REFORM OVER THE
NRN HI PLNS EARLY SUN.
FARTHER SE...SATELLITE AND SFC/UPR AIR DATA SHOW AN AREA OF LOW
PRESSURE CONTINUING TO SLOWLY DEVELOP OVER THE CNTRL GULF CST. THIS
FEATURE IS FORECAST TO DRIFT SLOWLY N AS UPR RIDGE BUILDS ALONG THE
E CST.
...NRN RCKYS/NRN HI PLNS...
MOISTURE EXPECTED TO REMAIN COMPARATIVELY LIMITED /PW AROUND 0.75
INCH/ OVER THE NRN RCKYS TODAY INVOF DEVELOPING SFC WAVE. SOMEWHAT
GREATER MOISTURE /PW AOA 1.00 INCH/ MAY APPEAR BY EVE OVER THE ERN
HALF OF MT. OTHERWISE...AN AREA OF RICHER MOISTURE SHOULD PERSIST
FARTHER S OVER AZ AND WRN NM.
STRENGTHENING SW FLOW ALOFT AHEAD OF AMPLIFYING UPR TROUGH SHOULD
SUPPORT A GRADUAL EWD SHIFT OF MID/UPR LVL MOISTURE PLUME.
HOWEVER...FLOW MAY REMAIN SUFFICIENTLY SLY E OF SFC WAVE TO ALLOW
ENOUGH MOISTURE /SFC DEWPOINTS IN THE UPR 40S F/ TO SPREAD NEWD AND
SUPPORT LATE AFTN/EVE STORMS OVER ERN ID...SW MT AND POSSIBLY NW WY.
STRONG SFC HEATING SHOULD BOOST SBCAPE TO AOB 500 J/KG.
COUPLED WITH INCREASING UPR DIVERGENCE WITH UPR TROUGH/SETUP MAY
SUPPORT INCREASING STORM COVERAGE THROUGH MID/LATE EVE ALONG AND N
OF SFC FRONT INTO CNTRL MT.
45-50 KT DEEP SSWLY SHEAR COULD YIELD A FEW CLUSTERS OF SUSTAINED
STORMS AND POSSIBLY SUPERCELLS WITH A RISK FOR DMGG WINDS AND HAIL.
...AZ...
COMPLEX SETUP OVER THE SWRN DESERTS TODAY AS SOME LOW LVL MOISTURE
LIKELY WILL LINGER BENEATH DRYING/STRENGTHENING SW FLOW ALOFT AHEAD
OF APPROACHING TROUGH. SATELLITE/MODELS DO NOT SUGGEST PRESENCE OF
AN UPR LVL FEATURE TO FOCUS LARGE SCALE ASCENT OVER THE REGION. BUT
SETUP APPEARS POTENTIALLY SUPPORTIVE OF A CONDITIONAL HYBRID-TYPE
SVR EVENT...AS SWLY MID/UPR LVL FLOW WILL BE SUFFICIENT TO SUPPORT A
FEW SUSTAINED STORMS/POSSIBLE SUPERCELLS GIVEN SUFFICIENT LOW LVL
CONVERGENCE TO PRODUCE STRONG UPDRAFTS. ATTM BELIEVE THIS THREAT
WILL BE GREATEST OVER CNTRL/NRN PARTS OF THE STATE LATE THIS AFTN
AND EVE...ALONG AND N OF THE RIM.
...CNTRL GULF CST/LWR MS VLY...
LOW LVL SHEAR WILL INCREASE SOMEWHAT LATER TODAY OVER PARTS OF
LA...MS...AND AL AS AFOREMENTIONED LOW CONTINUES TO DEVELOP AND
DRIFTS SLOWLY NWD. LOW LVL SPEED/DIRECTIONAL SHEAR COULD BECOME
SUFFICIENT TO POSE A THREAT FOR THE THREAT FOR TORNADOES GIVEN HI PW
OVER REGION. HOWEVER...UNCERTAINTY REMAINS REGARDING STORM
MODE/LIKELIHOOD FOR POTENTIAL SUSTAINED LOW LVL UPDRAFTS OVER LAND
CONSIDERING EXPANDING SHIELD OF MULTI-LAYERED CLOUDS NOW SPREADING N
AHEAD OF SYSTEM.
..CORFIDI.. 08/28/2010
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