SPC AC 161301      STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK    DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.      VALID 161300Z - 171200Z    THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT    ACROSS MINNESOTA...WESTERN WISCONSIN...NORTHERN AND WESTERN IOWA...    EXTREME EASTERN NORTH DAKOTA...EASTERN SOUTH DAKOTA AND    NORTHEASTERN NEBRASKA. THE HIGH RISK AREA IS TO THE RIGHT OF A    LINE FROM 35 NE ELO 45 SSW LSE 45 WNW LWD 15 S LNK 20 W EAR 20 SSW    MHE 20 NNW ATY 80 NE DVL.      SURROUNDING THE HIGH RISK AREA...THERE IS A SLGT RISK OF SVR TSTMS    TO THE RIGHT OF A LINE FROM 45 WNW ANJ 15 SE CGX 35 SSE IRK 10 SSE    EMP 40 S RSL 40 ENE GLD 30 NW LBF 35 N 9V9 15 WNW ABR 65 NE MOT.    THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM    15 S ABI 45 ENE GAG 20 SE BVO 30 ESE MLC 40 WNW TYR 15 NE ACT    40 S SEP 15 S ABI.    GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 ENE 63S    25 SSW S80 50 SSE BNO 25 W LMT 45 SSW OTH.    GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 SE TLH 35 SSE CSG    30 NW BHM 25 S GLH 45 SE LFK 25 ENE CRP ...CONT... 30 SSW P07    35 ESE BGS 30 ENE CDS 30 N GAG 30 SSW GCK 25 NNW CAO 55 S LVS    70 WNW GUP 25 N U17 50 N PUC 20 NE RWL 35 N BFF 15 NE RAP    60 NNE ISN.      A SIGNIFICANT SEVERE WEATHER EVENT APPEARS LIKELY THIS AFTERNOON    AND EVENING ACROSS PORTIONS OF THE CENTRAL PLAINS INTO THE UPPER    MIDWEST. STRONG UPPER-LEVEL TROUGH...NOW OVER ERN ID/UT...WILL    SHIFT ENEWD INTO THE PLAINS THIS AFTERNOON...REACHING THE WRN GREAT    LAKES BY 17/12Z. THE ACCOMPANYING INTENSE SURFACE LOW IS PROGGED    TO MOVE THROUGH THE NRN PLAINS AND INTO NWRN MN BY 00Z...AND INTO    ONTARIO BY THE END OF THE PERIOD.    ...CENTRAL PLAINS TO THE UPPER MIDWEST...    SLY WINDS OVER THE PLAINS TODAY WILL CONTINUE TO TRANSPORT MOISTURE    NWD...WITH MID 60 F SURFACE DEWPOINTS EXPECTED TO REACH MN BY THIS    AFTERNOON. STRONG SURFACE HEATING EXPECTED OVER MUCH OF THE HIGH    RISK AREA TODAY COMBINED WITH STEEP LAPSE RATES /AOA 8.0 C/KM/    ALREADY OVER THIS REGION WILL SUPPORT MUCAPES OF 2000-3000 J/KG    THIS AFTERNOON.      AS THE UPPER TROUGH MOVES INTO THE CENTRAL/NRN PLAINS THIS    AFTERNOON...CONVECTION IS EXPECTED TO DEVELOP NEAR THE COLD FRONT/    DRY LINE INTERSECTION OVER CENTRAL NEB BETWEEN 18-21Z. ETA    SUGGESTS CONVECTION WILL THEN FORM FROM NWRN MN SWD TO ERN NEB    AFTER 21Z. DRY MID-LEVELS EVIDENT ON OBSERVED 12Z SOUNDINGS AND    ETA FORECAST SOUNDINGS COMBINED WITH STEEP LAPSE RATES AND UNI-    DIRECTIONAL SSWLY WINDS WILL FAVOR A PRIMARY THREAT OF STRONG AND    DAMAGING WINDS. HOWEVER...ISOLATED TORNADOES WILL BE POSSIBLE...    GIVEN THE HIGH CAPE VALUES AND FORECAST WIND FIELDS.    THE GREATEST POTENTIAL FOR TORNADOES WILL BE OVER NRN MN WITH THE    INITIAL STORMS THAT DEVELOP EAST OF THE SYNOPTIC LOW WHERE STORMS    MAY ENCOUNTER BACKED LOW-LEVEL WINDS. A SECOND INCREASED TORNADO    THREAT AREA MAY DEVELOP OVER ERN NEB THIS AFTERNOON WHERE THERE    SHOULD BE BACKED LOW-LEVEL WINDS ALONG AND EAST OF THE TRIPLE    POINT.    AS THE UPPER TROUGH MOVES NEWD INTO THE UPPER MIDWEST THIS    EVENING...STRONG TO SEVERE STORMS WILL SPREAD INTO THE REST OF    MN/WRN WI AND NRN IA...WITH WIND AND HAIL BEING THE PRIMARY THREATS    DURING THIS TIME.    ...SRN PLAINS...    A SECOND UPPER FEATURE OF IMPORTANCE TODAY IS THE SHORT WAVE TROUGH    OVER SERN NM/SWRN TX THIS MORNING...AS IT MOVES NEWD THROUGH THE    SRN PLAINS TODAY. CURRENT WATER VAPOR SATELLITE TRENDS INDICATE    UPWARD VERTICAL MOTION WITH THIS TROUGH TO MOVE INTO SWRN    OK/CENTRAL TX BY 18Z AND THEN THROUGH THE REST OF OK/NRN TX BY    00Z...WHICH IS SLOWER THAN CURRENT/PREVIOUS ETA RUNS. ALTHOUGH ETA    FORECAST SOUNDINGS INDICATE A WEAK CAP LOCATED AROUND 800 MB OVER    OK INTO NRN TX...KINEMATIC AND THERMODYNAMIC FIELDS SUGGEST A    THREAT FOR SEVERE STORMS...IF STORMS CAN BREAK THE CAP. TIMING OF    THE SHORT WAVE WILL BE CRITICAL FOR THE INITIATION OF STORMS THIS    AFTERNOON...RESULTING IN THE ADDED SLIGHT RISK AREA FOR THE SRN    PLAINS TO BE CONDITIONAL.      REGIONAL RADARS HAVE INDICATED AN OVERALL DECREASE IN THE ONGOING    CONVECTION OVER CENTRAL TX DURING THE LAST HOUR OR SO. THIS WOULD    SUGGEST THAT THE CURRENT CLOUD COVER FROM THIS CONVECTION SHOULD    NOT EXPAND ANY FURTHER IN AREAL COVERAGE. THESE CLOUDS ARE    EXPECTED TO MOVE INTO SWRN MO/WRN AR BY MID-AFTERNOON...ALLOWING    SUFFICIENT HEATING/ DESTABILIZATION TO OCCUR BY MID-LATE AFTERNOON    OVER CENTRAL OK/NRN TX. HOWEVER...IF CLOUDS REMAIN OVER THIS    REGION LONGER...PREVENTING STRONG SURFACE HEATING...THIS WILL    INHIBIT THE SEVERE POTENTIAL.      A DRY LINE IS PROGGED TO MIX EWD TODAY REACHING WRN OK INTO NW    NORTH CENTRAL TX BY 00Z. ABUNDANT LOW-LEVEL MOISTURE EXISTS OVER    OK SWD INTO TX WITH SURFACE DEWPOINTS IN THE MID-UPPER    60S...COMBINED WITH EXPECTED SURFACE HEATING/COOLING MID-LEVEL    TEMPERATURES WILL RESULT IN MUCAPE RANGING FROM 2000-2500    J/KG....EAST OF THE DRY LINE. IF LOW LEVEL CONVERGENCE ALONG THE    DRY LINE IS SUFFICIENT TO BREAK THE CAP...LOW-LEVEL AND DEEP LAYER    SHEAR WILL BE MORE THAN SUFFICIENT FOR ORGANIZED STORMS/SUPERCELLS    PRODUCING TORNADOES...LARGE HAIL AND STRONG WINDS. SEVERE THREAT    IS EXPECTED TO DIMINISH AFTER SUNSET.      ..PETERS.. 04/16/02    NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 1630Z