To the average person, this 5 days may not seem like much. But to the experienced weather forecaster, this means a lot. It means the SPC has an unusually high amount of confidence this will happen, as day 6 outlooks are rarely released this far out.
The following is the SPC's discussion. We have bolded the parts you as an everyday person will be able to understand, as this discussion is meant for more experienced weather folk.
ON SUN/D4...AN UPPER TROUGH WILL BE DEAMPLIFYING ACROSS THE UPPER MS VALLEY/GREAT LAKES REGION...WITH A BROAD BELT OF SWLY FLOW ALOFT EXTENDING SWWD INTO THE SWRN STATES INTO THE BASE OF THE NEXT TROUGH. WITH SLIGHTLY RISING HEIGHTS ALOFT...SWLY FLOW WILL INCREASE OVER THE PLAINS HELPING TO BRING GULF MOISTURE NWD OVERNIGHT. BY MON/D5...MODELS ARE IN GOOD AGREEMENT BRINGING THE UPPER TROUGH AND LEADING EDGE OF HEIGHT FALLS ACROSS THE FOUR CORNERS STATES AND INTO THE SRN HIGH PLAINS BY MON AFTERNOON. LOW PRESSURE IS FORECAST TO DEEPEN OVER THE TX PANHANDLE AREA...WITH SLY FLOW INTENSIFYING THROUGH THE DAY AND OVERNIGHT WITH A 50+ KT LLJ AND AT LEAST LOWER 60S F DEWPOINTS INTO OK. THE GFS SHOWS A WARM FRONT ALONG THE KS/OK BORDER...BUT THE ECMWF SUGGESTS THIS FEATURE WILL BE MUCH FARTHER N INTO NRN KS/SRN NEB. WHILE THE NRN EXTENT OF ANY SEVERE THREAT MAY BE IN QUESTION...IT APPEARS LIKELY THAT SEVERE STORMS WILL OCCUR OVER PORTIONS OF WRN OK AND NWRN TX NEAR THE DRYLINE. HERE...STEEP LAPSE RATE PROFILES SHOULD EXIST. WHILE INSTABILITY WILL NOT BE PARTICULARLY LARGE WITH ONLY NEAR 60 DEWPOINTS...SHEAR PROFILES WILL BE QUITE FAVORABLE FOR SUPERCELLS DURING THE AFTERNOON AND EVENING. A FEW TORNADOES ALONG WITH HAIL AND WIND WILL BE POSSIBLE. OVERNIGHT...A COLD FRONT WILL EVENTUALLY MOVE INTO CNTRL OK AND TX. IT IS POSSIBLE MORE CONVECTION WILL OCCUR ALONG THIS FRONT...BUT THE PRIMARY THREAT WILL LIKELY BE WITH DIURNAL SUPERCELLS. BY TUE/D6...MODELS START TO DIVERGE WITH THE ECMWF LIFTING THE UPPER LOW/JET MAX NEWD MUCH QUICKER THAN MANY OF THE MREF MEMBERS. EVEN WITH THESE DIFFERENCES...STRONG SWLY FLOW ALOFT WILL EXIST ATOP MID TO UPPER 60S F DEWPOINTS AND FORCING ALONG THE COLD FRONT AND DRYLINE. THUS...SOME RESIDUAL SEVERE THREAT IS LIKELY FROM E TX INTO AR AND LA WITH THE MAIN THREAT DAMAGING WINDS AND A FEW TORNADOES.