USA Weather — Severe Weather Division
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...
...SUMMARY...
A SIGNIFICANT SEVERE WEATHER EVENT IS FORECAST TO UNFOLD ACROSS THE CENTRAL AND SOUTHERN GREAT PLAINS INTO THE OZARKS TODAY AND TONIGHT. SEVERAL STRONG TORNADOES, WIDESPREAD VERY LARGE HAIL, AND SEVERE WIND GUSTS OF 60-85 MPH ARE ALL EXPECTED.
...SYNOPSIS...
A WELL DEFINED UPPER-LEVEL LOW IS APPARENT ON WATER VAPOR IMAGERY THIS MORNING ACROSS THE NORTHERN HIGH PLAINS. THIS UPPER LOW WILL MEANDER IN THE SAME LOCATION AS A LARGE NEGATIVELY TILTED UPPER TROUGH OVER THE ROCKIES SLOWLY EJECTS EASTWARD INTO THE GREAT PLAINS. AT THE SURFACE, A LARGE, OCCLUDED CYCLONE OVER THE CENTRAL PLAINS IS EXPECTED TO SLOWLY SHIFT EASTWARD INTO THE MID/UPPER MISSISSIPPI VALLEY TONIGHT. A DRYLINE EXTENDING SOUTHWARD FROM THE TRIPLE POINT WILL GRADUALLY MIX EASTWARD DURING PERIOD TODAY BEFORE BEING OVERTAKEN BY A COLD FRONT OVERNIGHT.
...SOUTHERN/CENTRAL PLAINS/OZARKS...
A PLUME OF RICH GULF MOISTURE WITH DEWPOINTS IN THE UPPER 60S TO MID-70S IS RAPIDLY ADVECTING NORTHWARD AND WILL REACH AS FAR NORTH AS THE MID MISSOURI VALLEY BY THIS AFTERNOON AND EVENING. VERY STEEP LAPSE RATES ACROSS THE WARM SECTOR – IN ADDITION TO INTENSE SURFACE HEATING – WILL CONTRIBUTE TO INTENSE BUOYANCY WITH MLCAPE RISING INTO THE 3000-5000 J/KG RANGE, WITH HIGHEST VALUES NEAR THE DRYLINE ACROSS CENTRAL TEXAS INTO EAST-CENTRAL KANSAS.
STRENGTHENING SURFACE CONVERGENCE AND INTENSIFYING HEIGHT FALLS WILL RESULT IN INTENSE CONVECTIVE DEVELOPMENT BY EARLY AFTERNOON, INITIALLY ALONG THE DRYLINE, SPREADING EASTWARD. INTENSIFYING DEEP-LAYER FLOW CONTRIBUTING TO VERY LONG, CURVING HODOGRAPHS WILL SUPPORT A MIXED CONVECTIVE MODE, WITH INTENSE SUPERCELLS INITIALLY BEFORE EVOLVING INTO LINE SEGMENTS AND STORM CLUSTERS. WIDESPREAD DESTRUCTIVE HAIL POTENTIALLY EXCEEDING 3 TO 4 INCHES IN DIAMETER AND SEVERE WIND GUSTS OF 60-85MPH ARE LIKELY, WITH MULTIPLE ROUNDS EXPECTED IN MANY LOCATIONS. SEVERAL STRONG TORNADOES WILL LIKELY EVOLVE, PARTICULARLY ACROSS EASTERN OKLAHOMA WHERE GREATER BUOYANCY AND LOW-LEVEL HELICITY EVOLVE.
EVENTUAL UPSCALE GROWTH INTO AN MCS IS EXPECTED THIS EVENING, SHIFTING INTO THE OZARKS/MISSISSIPPI VALLEY WITH TIME. WIDESPREAD DAMAGING WINDS AND EMBEDDED TORNADOES REMAIN LIKELY WITH THESE STORMS.