MESOSCALE DISCUSSION 1224,AREAS AFFECTED...PARTS OF NERN NEB...ERN SD...SERN ND INTO CNTRL MN CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

        MESOSCALE DISCUSSION 1224     NWS STORM PREDICTION CENTER NORMAN OK     0456 PM CDT TUE JUN 19 2012          AREAS AFFECTED...PARTS OF NERN NEB...ERN SD...SERN ND INTO CNTRL MN          CONCERNING...SEVERE POTENTIAL...WATCH LIKELY           VALID 192156Z - 192330Z          PROBABILITY OF WATCH ISSUANCE...80 PERCENT          SUMMARY...UNCERTAINTY LINGERS CONCERNING TIMING OF BOUNDARY LAYER     BASED WARM SECTOR DEVELOPMENT...AND INITIATION OF MORE VIGOROUS     CONVECTION WITHIN LOWER/MID TROPOSPHERIC WARM ADVECTION TO THE NORTH     OF THE WARM FRONT.  HOWEVER...ONE OR MORE WATCHES LIKELY WILL BE     NEEDED BY EARLY EVENING...PERHAPS WITHIN THE NEXT HOUR OR TWO.          DISCUSSION...VERY WARM ELEVATED MIXED LAYER AIR CONTINUES TO PROVIDE     STRONG INHIBITION TO CONVECTIVE DEVELOPMENT...BOTH IN THE WARM     SECTOR OF THE DEEP EASTERN SOUTH DAKOTA CYCLONE...AND WITHIN AT     LEAST A NARROW CORRIDOR TO THE NORTH OF THE WARM FRONT EXTENDING TO     THE EAST NORTHEAST...ACROSS PARTS OF CENTRAL MINNESOTA.  THE VERY     MOIST WARM SECTOR HAS BECOME MODERATE TO STRONGLY UNSTABLE BENEATH     STEEP MID-LEVEL LAPSE RATES...WITH MIXED LAYER CAPE NOW ON THE ORDER     OF 2000-3000+ J/KG.  AND DEEP LAYER SHEAR IS STRONG AND FAVORABLE     FOR SUPERCELLS...WITH LOW-LEVEL HODOGRAPHS SIZABLE AND SUPPORTIVE OF     TORNADIC POTENTIAL...MAINLY ALONG THE WARM FRONT.          LOW-LEVEL CONVERGENCE APPEARS MAXIMIZED NEAR THE SURFACE LOW...FROM     HURON INTO THE WATERTOWN AREA...AND DEEPENING CONVECTION IS ALREADY     EVIDENT TO THE NORTH OF HURON.  GUIDANCE IS ALSO SUGGESTIVE THAT A     WEAKNESS IN THE INHIBITION MAY EXIST ACROSS THIS     VICINITY...SOUTHWARD ALONG A PRE-FRONTAL SURFACE TROUGH INTO     NORTHEAST NEBRASKA...ALONG WHICH SHALLOWER CUMULUS DEVELOPMENT HAS     BEEN EVIDENT.  MEANWHILE...AN INCREASE IN STORM DEVELOPMENT DOES     APPEAR UNDERWAY TO THE NORTH OF THE WARM FRONT...ACROSS PARTS OF     SOUTHEASTERN NORTH DAKOTA INTO WEST CENTRAL MINNESOTA...WHICH THE     LATEST HIGH RESOLUTION RAPID REFRESH SUGGESTS MAY EXPAND     CONSIDERABLY AND GROW UPSCALE THROUGH THE 00-02Z TIME FRAME.          WHILE THE EVOLUTION OF CONVECTIVE DEVELOPMENT DURING THE NEXT FEW     HOURS REMAINS A BIT UNCLEAR...THE GREATEST SEVERE WEATHER     POTENTIAL...INCLUDING THE RISK FOR TORNADOES...APPEARS TO EXIST WITH     CONVECTION NEAR THE HURON/WATERTOWN AREAS...IF AND WHEN THE CAP     FINALLY BREAKS LATE THIS AFTERNOON.          ..KERR/KERR.. 06/19/2012               ATTN...WFO...DLH...MPX...FGF...FSD...ABR...BIS...LBF...          LAT...LON   45829878 46519772 46869632 47059514 46849402 46289359                 45509412 45029591 43809733 42889823 42909905 44209843                 44779874 45389902 45829878