MESOSCALE DISCUSSION 1107 NWS STORM PREDICTION CENTER NORMAN OK 0802 PM CDT SAT JUN 09 2012 AREAS AFFECTED...FAR NERN ND AND FAR NWRN MN CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 100102Z - 100130Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...AN ISOLATED TORNADO THREAT EXISTS ACROSS FAR NERN ND AND FAR NWRN MN DURING THE NEXT FEW HOURS. GIVEN A SOMEWHAT SMALL SPATIAL THREAT AREA...AND SOME UNCERTAINTY WITH THE NUMBER OF STORMS TO DEVELOP...THE PROBABILITY OF TORNADO WATCH ISSUANCE IS 40 PERCENT. DISCUSSION...RADAR IMAGERY IN NERN ND INDICATED A MORE ROBUST UPDRAFT HAD DEVELOPED BETWEEN 0015-0040Z IN WALSH COUNTY...AND IS NOW TRACKING INTO PEMBINA COUNTY. THIS TSTM FORMED JUST E/ESE OF A SURFACE LOW LOCATED IN NORTH CENTRAL/NERN ND /TOWNER AND CAVALIER COUNTIES/. A COLD FRONT EXTENDED SWD FROM THE LOW TO JUST E OF JMS AND INTO SD /25 W ABR/...WITH THIS BOUNDARY THEN EXTENDING SWWD THROUGH CENTRAL SD BETWEEN PIR AND 9V9. MEANWHILE...A WARM FRONT EXTENDED EWD STRADDLING THE INTERNATIONAL BORDER THROUGH FAR NERN ND/NWRN MN...AND THEN GENERALLY ALONG THE ONTARIO SIDE OF THE BORDER...N OF NORTH CENTRAL AND NERN MN. AN INCREASE IN LOW LEVEL CONVERGENCE INVOF THE SURFACE LOW AND COLD FRONT AS THESE FEATURES ADVANCED EWD INTO NERN ND AIDED IN WEAKENING INHIBITION FOR THE TSTM DEVELOPMENT OVER WALSH COUNTY. GIVEN THE DEGREE OF INSTABILITY AND BULK SHEAR...AN ORGANIZED THREAT FOR SUPERCELLS EXISTS...WITH AN INCREASED POTENTIAL FOR A TORNADO AS THIS STORM AND ANY ADDITIONAL ACTIVITY INTERACTS WITH GREATER LOW LEVEL SHEAR INVOF THE WARM FRONT. THE SEVERE WEATHER THREAT SHOULD BE LIMITED WITH SWD EXTENT ALONG THE COLD FRONT GIVEN A STRONGER CAP INTO SERN ND AND SD PER 00Z ABR/BIS SOUNDINGS. ..PETERS/THOMPSON.. 06/10/2012 ATTN...WFO...FGF...
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