SWODY1
SPC AC 171247
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT SAT SEP 17 2011
VALID 171300Z - 181200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL/SRN
PLAINS...
...CNTRL/SRN PLAINS...
A LEAD...LOW-AMPLITUDE...MID-LVL SHORTWAVE TROUGH MOVING ACROSS
CNTRL KS HAS ENHANCED THE LLJ /40-45 KTS/ EARLY THIS MORNING.
ELEVATED TSTMS WILL CONTINUE TO MOVE ENE OUT OF OK/KS AND INTO WRN
MO AND NRN AR THROUGH MID-MORNING WITH A GRADUAL WEAKENING TREND
OWING TO THE DECREASE/BACKING OF THE LLVL FLOW.
PROGRESSIVE UPR FLOW REGIME WILL CONTINUE TODAY WITH ANOTHER
FORMIDABLE IMPULSE EJECTING EWD FROM WRN CO/NWRN NM EWD TO THE
CNTRL/SRN PLAINS BY MID-AFTN. SLY LLJ WILL STRENGTHEN AGAIN THIS
AFTN AND TRANSPORT/MAINTAIN LWR-MID 60S SFC DEW POINTS SW OF A
RETREATING WRMFNT AND AHEAD OF A LEE TROUGH/FRONT ACROSS THE ERN
TX/OK PNHDLS AND SWRN/SCNTRL KS. H7-H5 LAPSE RATES OF 6.5-7.5 DEG C
PER KM TOPPING THIS REASONABLY RICH MOISTURE AND STRONG DIABATIC
HEATING WILL YIELD SBCAPES OF 1500-2500 J/KG. NRN EXTENT OF
SIGNIFICANT DESTABILIZATION WILL BE RELEGATED ROUGHLY S OF THE I-70
CORRIDOR IN KS...COINCIDENT WITH THE WRMFNT AND STEEPEST LLVL LAPSE
RATES. INSTABILITY AXIS WILL EXTEND INTO SW TX.
AS LARGE-SCALE ASCENT TIED TO THE UPR WAVE ARRIVES ACROSS THE HIGH
PLAINS...INHIBITION WILL WEAKEN AND SCTD TSTMS WILL LIKELY DEVELOP
BY MID-AFTN FROM SWRN/SCNTRL KS SWWD INTO W TX. WLY MID-LVL WINDS
WILL INCREASE TO 30-35 KTS...PARTICULARLY FROM THE TX/OK PNHDLS NWD
INTO KS AND RESULT IN MODEST DEEP-LAYER SHEAR. AS A RESULT...VAST
MAJORITY OF STORMS WILL BE MULTICELLS...BUT A COUPLE OF BRIEF
SLOW-MOVING SUPERCELLS WILL ALSO BE POSSIBLE. LARGE HAIL AND DMGG
WINDS WILL BE THE PRIMARY THREATS.
TONIGHT...AS THE WAVE CONTINUES AN ENE TREK ACROSS THE PLAINS AND
THE NOCTURNAL LLJ FURTHER INTENSIFIES...ONE OR MORE SMALL MCS/S MAY
EVOLVE ACROSS PORTIONS OF KS AND PERHAPS OK. SVR THREATS SHOULD
WANE WITH TIME DURING THE EVENING AS THE BOUNDARY LAYER
DECOUPLES...BUT A COUPLE OF SVR HAIL/GUSTY WIND REPORTS CANNOT BE
RULED OUT OVER SCNTRL/SERN KS AND CNTRL OK WELL AFTER DARK.
..RACY/COHEN.. 09/17/2011
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