All of Iowa

Severe Weather Possible Tuesday


…UPPER MS VALLEY THROUGH NRN AND CNTRL PLAINS REGIONS…

LEE TROUGHING WILL HAVE BECOME ESTABLISHED OVER THE HIGH PLAINS WITHIN THE QUASI-ZONAL UPPER FLOW REGIME. AS THE WARM FRONT LIFTS NWD A BROAD…MOIST WARM SECTOR WILL ADVECT THROUGH ERN PORTIONS OF THE PLAINS AND UPPER MS VALLEY AND GREAT LAKES WITH UPPER 50S TO NEAR 60 DEWPOINTS AS FAR NORTH AS THE ERN DAKOTAS INTO MN AND LOW-MID 60S FARTHER EAST AND SOUTH. ZONE OF MODERATE TO STRONG INSTABILITY WILL DEVELOP IN THIS REGION AS PLUME OF STEEP LAPSE RATES ADVECT EWD ABOVE RETURNING MOIST AXIS AND AS THE BOUNDARY LAYER WARMS DURING THE AFTERNOON. MLCAPE SHOULD RANGE FROM 1500 TO 2000 J/KG OVER THE UPPER MS VALLEY TO NEAR 3000 J/KG OVER THE CNTRL PLAINS.

AS LOW AMPLITUDE SHORTWAVE TROUGH APPROACHES FROM WEST…STORMS MAY DEVELOP WITHIN ZONE OF DEEPER FORCING ALONG AND EAST OF SEWD ADVANCING COLD FRONT ACROSS THE ERN DAKOTAS INTO NEB WITH MORE ISOLATED ACTIVITY POSSIBLE FARTHER SOUTH ALONG THE DRYLINE ACROSS KS. VERTICAL SHEAR FROM 35-45 KT WILL SUPPORT ORGANIZED STORMS INCLUDING SUPERCELLS AND BOWING SEGMENTS. LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS…BUT 0-2 KM HODOGRAPHS WILL ALSO BE SUFFICIENT FOR ISOLATED TORNADOES. ACTIVITY WILL CONTINUE EAST INTO WRN PORTIONS OF THE GREAT LAKES AREA DURING THE EVENING WITH A CONTINUED SEVERE THREAT.