SPC 1300Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0759 AM CDT WED JUN 13 2012 VALID 131300Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN HIGH PLNS... ...SYNOPSIS... PREVAILING ZONAL FLOW OVER THE LWR 48 WILL SOMEWHAT AMPLIFY TNGT THROUGH THU AS SHORTWAVE TROUGH NOW OVER WA CONTINUES ENE INTO SRN SK AND EVOLVES INTO A CLOSED LOW...AND HEIGHTS RISE FROM THE CNTRL PLNS TO THE UPR MS VLY/UPR GRT LKS. THIS PATTERN SHOULD RESULT IN SOME WEAKENING OF MID LVL WLY FLOW OVER THE CNTRL AND SRN PLNS RELATIVE TO YESTERDAY. APPROACH OF WA UPR TROUGH WILL MAINTAIN LEE SFC TROUGH OVER THE NRN AND CNTRL HI PLNS. COLD FRONT ATTENDANT TO THE UPR IMPULSE SHOULD REACH ERN WY AND THE WRN DAKOTAS LATE THIS AFTN...AND CONTINUE E INTO THE ERN DAKOTAS/WRN NEB BY 12Z THU. PERSISTENT SLY FLOW AHEAD OF THE FRONT/LEE TROUGH WILL MAINTAIN MODEST MOISTURE INFLOW TO REGION N OF DECAYING MCSS NEAR THE RED RVR. ...NRN PLNS TODAY/TNGT... TSTMS NOW OVER NERN NEB/ERN SD ARE BEING SUPPORTED BY LOW LVL WAA ON ERN FRINGE OF LLJ. THIS JET SHOULD SHIFT NEWD INTO MN TODAY AS ASSOCIATED UPR IMPULSE DEAMPLIFIES AND TRACKS NE TOWARD THE UPR GRT LKS. WITH INSTABILITY INCREASINGLY LIMITED WITH NERN EXTENT...SVR POTENTIAL WITH THE STORMS SHOULD REMAIN MINIMAL. OTHER TSTMS SHOULD FORM OVER THE WRN DAKOTAS AND FAR ERN WY LATER TODAY AS THE COLD FRONT MOVES INTO REGION. ALTHOUGH SUFFICIENT WSWLY MID LVL FLOW WILL EXIST FOR SUSTAINED/ORGANIZED ACTIVITY GIVEN STEEP LOW TO MID LVL LAPSE RATES...SPARSE MOISTURE IS EXPECTED TO LIMIT INTENSITY OF THESE INITIAL STORMS. BY EVE...SLY LLJ SHOULD STRENGTHEN ACROSS SD WITH THE CONTINUED EWD ADVANCE/AMPLIFICATION OF WA UPR TROUGH. THIS WILL PROMOTE FURTHER MOISTENING BENEATH STRENGTHENING MID LVL FLOW...AND MAY SUPPORT REJUVENATION OF EARLIER STORMS AND/OR NEW STORM DEVELOPMENT ALONG/AHEAD OF COLD FRONT/LEE TROUGH IN THE WRN DAKOTAS. THIS ACTIVITY COULD GROW UPSCALE INTO A SMALL CLUSTER OR TWO...POSING A THREAT FOR SVR HAIL/WIND E/SE ACROSS CNTRL AND ERN PORTIONS OF THE DAKOTAS THROUGH EARLY THU. ...SRN HIGH PLNS SEWD INTO TX TODAY... CNTRL TX CONVECTIVE BAND APPEARS TO BE SUPPORTED ATTM BY UPLIFT ALONG OUTFLOW BOUNDARY ASSOCIATED WITH DISSIPATING N TX/S OK MCS/MCV. AREA SOUNDINGS SUGGEST INCREASINGLY STRONG EML CAPPING AND DIVERGENT LOW LVL FLOW WITH SE EXTENT FROM THE CNTRL TX STORMS. THIS MAY PROHIBIT OR AT LEAST LIMIT ADDITIONAL STORM DEVELOPMENT ALONG THE BOUNDARY AS IT CONTINUES SEWD LATER TODAY...DESPITE ONSET OF DAYTIME HEATING. NEVERTHELESS...WILL MAINTAIN LOW CONDITIONAL PROBABILITIES FOR SVR WIND ACROSS S CNTRL TX FOR THE POSSIBILITY THAT A STRONG CLUSTER DOES INDEED EVOLVE GIVEN RICH MOISTURE PRESENT OVER REGION. MEANWHILE...RELATIVELY WEAK LOW LVL LAPSE RATES SHOULD LIMIT AFTN STORM STRENGTH/LONGEVITY ON THE E SIDE OF MCS...I.E. OVER NE TX...ALTHOUGH ISOLD INSTANCES OF LOCALLY DMGG WIND MAY OCCUR. LATER TODAY...OTHER STORMS SHOULD FORM ALONG LEE TROUGH/DRY LINE FROM SE CO/ERN NM INTO W TX AND/OR THE WRN TX PANHANDLE. WHILE UPR LVL FORCING WILL BE WEAK...AMPLE SPEED/DIRECTIONAL SHEAR WILL EXIST FOR DISCRETE SUPERCELLS WITH LARGE HAIL/LOCALLY DMGG WIND AND PERHAPS A TORNADO INTO EARLY EVE. SOME OF THESE MAY EVOLVE INTO A SMALL SE-MOVING CLUSTER TNGT. ...KS/NEB THIS AFTN/EVE... ISOLD STRONG TO BRIEFLY SVR STORMS WITH HAIL/STRONG WINDS MAY FORM THIS LATE AFTN ALONG LEE TROUGH/DRY LINE OVER WRN PORTIONS OF KS/NEB. WEAK FORCING FOR ASCENT AND RELATIVELY LIMITED MOISTURE SHOULD LIMIT STORM STRENGTH/DURATION. ..CORFIDI/LEITMAN.. 06/13/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1300.html
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