AREA COUNTIES: MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-PAGE.   429 AM CDT SUN MAY 11 2014

A MODERATE RISK OF SEVERE STORMS WILL EXIST ACROSS MUCH OF THE REGION TODAY AND TONIGHT.  SEVERE THUNDERSTORMS WILL BE POSSIBLE IN SOUTHEAST NEBRASKA AND A SMALL PORTION OF SOUTHWEST IOWA THIS MORNING. LARGE HAIL UP TO GOLF BALL SIZE AND DAMAGING WINDS COULD OCCUR WITH THE STRONGER STORMS. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 AM FOR THIS AREA. THESE STORMS ARE DEVELOPING NORTH OF A WARM FRONT IN RESPONSE TO A STRENGTHENING LOW LEVEL JET AS A LARGE UPPER LEVEL LOW ORGANIZES ACROSS THE SOUTHWESTERN UNITED STATES.

THE NORTHWARD LIFTING WARM FRONT SHOULD BECOME THE FOCUS FOR ADDITIONAL SEVERE STORMS BY NOON AND BEYOND. THE FRONT AT THAT TIME COULD LIFT TO A CRETE NEBRASKA TO RED OAK IOWA LINE. STORMS SHOULD FORM ALONG THE WARM FRONT DURING THE AFTERNOON. SHEAR PROFILES ARE SUFFICIENT FOR ALL MODES OF SEVERE WEATHER INCLUDING VERY LARGE HAIL…DAMAGING WINDS AND TORNADOES.

THE BEST AREA FOR THE SEVERE STORM DEVELOPMENT APPEARS TO BE ABOUT 10 TO 25 MILES EITHER SIDE OF THE WARM FRONT AS IT LIFTS THROUGH AND ALONG THE I80 CORRIDOR BY EARLY AFTERNOON…THEN LIFTING NORTH TOWARD THE PLATTE RIVER VALLEY AND INTO NORTHWEST IOWA LATE IN THE AFTERNOON. A LINE OF SEVERE THUNDERSTORMS SHOULD ALSO DEVELOP SOUTHWESTWARD LATE THIS AFTERNOON FROM A TRIPLE POINT WHICH COULD BE BETWEEN COLUMBUS AND LINCOLN…THEN MOVE EASTWARD ACROSS THE REGION THROUGH THE EVENING.

IN ADDITION TO THE SEVERE WEATHER THREAT…DEEPER MOISTURE RETURNING TO THE REGION…COMBINED WITH STORMS REPEATEDLY TRACKING ACROSS THE SAME LOCATIONS COULD BRING AREAS OF HEAVY RAIN. WHILE 3 HOURLY FLASH FLOOD GUIDANCE VALUES REMAIN FAIRLY HIGH…MULTIPLE STORMS MOVING ACROSS THE SAME AREAS COULD TRIGGER ISOLATED FLASH FLOODING BY LATE AFTERNOON AND EVENING AS WELL.