DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 100557
SWODY1
SPC AC 100555

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT THU OCT 10 2013

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PORTIONS OF THE CENTRAL AND
SRN HIGH PLAINS...

...SYNOPSIS...
A VIGOROUS SWRN CONUS UPPER TROUGH IS FORECAST TO PIVOT EWD AND THEN
NEWD ACROSS THE CENTRAL ROCKIES AND CNTRL HIGH PLAINS WHILE BECOMING
INCREASINGLY NEGATIVELY TILTED...EVENTUALLY PHASING WITH A NRN
STREAM UPPER TROUGH. AN ASSOCIATED SFC LOW IS FORECAST TO DEEPEN
ACROSS WRN SD BY EARLY FRI MORNING...WITH AN ATTENDANT COLD FRONT
SWEEPING EWD ACROSS THE GREAT PLAINS. FARTHER E...A WEAK AND
QUASI-STATIONARY UPPER LOW ALONG THE MID-ATLANTIC COAST WILL MEANDER
ERRATICALLY...UNDER THE INFLUENCE OF A LARGE-SCALE UPPER RIDGE
ENCOMPASSING THE ERN HALF OF THE CONUS.

...CENTRAL AND SRN HIGH PLAINS...
A LEE SFC TROUGH/DRYLINE WILL BECOME ESTABLISHED ACROSS THE CENTRAL
HIGH PLAINS THIS AFTERNOON...WITH MODEST MOISTURE RETURN NWD
RESULTING IN SFC DEWPOINTS REACHING THE MID-40S TO LOW-50S F. AN
APPROACHING SPEED MAX ASSOCIATED WITH THE AFOREMENTIONED UPPER
TROUGH WILL PROMOTE CONVECTIVE INITIATION DURING THE LATE
AFTERNOON...WITHIN A NARROW CORRIDOR OF LITTLE TO NO CAPPING
JUXTAPOSED WITH MLCAPE VALUES PEAKING NEAR 500-800 J/KG. THE MAIN
VORTICITY LOBE ASSOCIATED WITH THE UPPER TROUGH IS FORECAST TO EJECT
OUT OF THE ROCKIES AFTER PEAK HEATING. HOWEVER...SOME POTENTIAL FOR
ISOLATED HIGH-BASED SUPERCELLS WILL EXIST ACROSS THE CNTRL HIGH
PLAINS DEVELOPING INVOF THE LEE SFC TROUGH...WITH AN ACCOMPANYING
THREAT FOR LARGE HAIL AND DMGG WIND GUSTS. THE TORNADO THREAT IS
EXPECTED TO BE LIMITED BY MARGINAL BOUNDARY LAYER MOISTURE AND SFC
T-TD SPREADS NEAR 30 F...DESPITE FAVORABLE LOW-LEVEL AND DEEP-LAYER
SHEAR.

STRONGER FORCING FOR ASCENT ASSOCIATED WITH THE PRIMARY VORTICITY
LOBE IS EXPECTED TO RESULT IN A FORCED LINE OF CONVECTION DEVELOPING
ACROSS ERN CO DURING THE EVENING. WHILE MOISTURE WILL BE RELATIVELY
MORE SCANT...STEEP LOW-LEVEL LAPSE RATES AND A STRENGTHENING
LOW-LEVEL JET WILL BE FAVORABLE FOR STRONG-SVR WIND GUSTS.
HOWEVER...THE TEMPORAL WINDOW FOR SFC-BASED CONVECTION AND THE
ASSOCIATED THREAT FOR DMGG WINDS IS SOMEWHAT UNCERTAIN AS THE LINE
PROGRESSES EWD...AS DIURNAL COOLING AND INCREASING MLCINH WILL
RESULT IN TSTMS BECOMING ELEVATED WITH TIME.

..ROGERS/GARNER.. 10/10/2013

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