MD 0697 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR NRN OK…SCNTRL THROUGH ERN KS…EXTREME SERN NEB AND WRN MO
MESOSCALE DISCUSSION 0697 NWS STORM PREDICTION CENTER NORMAN OK 1251 PM CDT SUN MAY 19 2013 AREAS AFFECTED...NRN OK...SCNTRL THROUGH ERN KS...EXTREME SERN NEB AND WRN MO CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 191751Z - 191945Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...STORMS ARE EXPECTED TO DEVELOP BY 20Z...MOST LIKELY OVER SCNTRL KS INTO NCNTRL OK. STORMS WILL SUBSEQUENTLY CONTINUE THROUGH THE WARM SECTOR OVER ERN KS...NERN OK AND EVENTUALLY WRN MO THIS EVENING. INITIAL THREATS WILL BE SUPERCELLS WITH VERY LARGE HAIL AND TORNADOES...A FEW OF WHICH COULD BE STRONG. DISCUSSION...EARLY THIS AFTERNOON A DRYLINE EXTENDS FROM WRN TX INTO FAR WRN OK THEN NWWD INTO THE OK PANHANDLE WHERE IT INTERSECTS A COLD FRONT. A WEAKENING OUTFLOW BOUNDARY EXISTS NEAR THE OK/KS BORDER AND HAS BEEN LIFTING SLOWLY NWD. SATELLITE IMAGERY ALSO INDICATES AN EWD PROPAGATING GRAVITY WAVE FROM SCNTRL KS INTO NWRN OK. UPPER 60S DEWPOINTS ARE ADVECTING NWD THROUGH THE WARM SECTOR BENEATH VERY STEEP /8-9 C/KM/ MID LEVEL LAPSE RATES. THESE FACTORS ALONG WITH DIABATIC WARMING WILL CONTRIBUTE TO STRONG INSTABILITY WITH 3000-4000 J/KG MLCAPE BY MID AFTERNOON. WARM AIR AT THE BASE OF THE EML IS SERVING TO CAP THE BOUNDARY LAYER TO SFC BASED STORMS IN THE NEAR TERM. HOWEVER...MESOSCALE FORCING FOR ASCENT ASSOCIATED WITH EWD PROPAGATING GRAVITY WAVE LOCATED WITHIN UPPER JET EXIT REGION AS WELL AS DRYLINE CONVERGENCE SHOULD CONTRIBUTE TO THUNDERSTORM INITIATION AS CONVECTIVE TEMPERATURES ARE REACHED TOWARD MID-LATE AFTERNOON. MID-UPPER JET ROTATING THROUGH BASE OF THE TROUGH IS RESULTING IN 50+ KT DEEP SHEAR SUPPORTIVE OF SUPERCELLS. 0-2 KM HODOGRAPHS WILL ALSO BE SUFFICIENT FOR LOW LEVEL MESOCYCLONES...AND THREAT FOR A FEW STRONG TORNADOES WILL EXIST GIVEN THE STEEP LAPSE RATES AND MAGNITUDE OF INSTABILITY. ..DIAL/KERR.. 05/19/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SGF...EAX...TSA...OAX...TOP...ICT...OUN...DDC... LAT...LON 36539841 37939876 40319628 39659446 36729528 36539841
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