COUNTIES IN IOWA: MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-PAGE 615 PM CDT FRI APR 13 2012 National Weather Service/Valley, NE

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA…WEST CENTRAL IOWA…EAST CENTRAL NEBRASKA…NORTHEAST NEBRASKA AND SOUTHEAST NEBRASKA.

DAY ONE…TONIGHT:

ISOLATED THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT OVER SOUTHEAST NEBRASKA AND FAR SOUTHERN SOUTHWEST IOWA. SEVERE WEATHER IS GENERALLY NOT EXPECTED WITH THIS ACTIVITY.

DAYS TWO THROUGH SEVEN…SATURDAY THROUGH THURSDAY:

THERE IS A HIGH RISK FOR SEVERE THUNDERSTORMS ACROSS EASTERN NEBRASKA AND WESTERN IOWA ON SATURDAY. THE MAIN THREAT FROM SEVERE THUNDERSTORMS WILL BE AFTER 3 PM AND BEFORE MIDNIGHT ON SATURDAY NIGHT. THE MAIN THREAT FROM THESE THUNDERSTORMS WILL BE TORNADOES…VERY LARGE HAIL AND DAMAGING WINDS.

THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY ON SATURDAY MORNING ACROSS SOUTHEAST NEBRASKA. THESE THUNDERSTORMS ARE THEN EXPECTED TO TRACK NORTHEAST ACROSS EASTERN NEBRASKA AND WESTERN IOWA THROUGH THE MORNING AND EARLY AFTERNOON. LARGE HAIL WILL BE POSSIBLE WITH THIS ACTIVITY.

A MORE POTENT SEVERE WEATHER THREAT IS THEN EXPECTED TO DEVELOP LATER IN THE AFTERNOON AFTER THE INITIAL THUNDERSTORMS MOVE OUT OF THE AREA. THESE THUNDERSTORMS ARE FIRST EXPECTED TO DEVELOP OVER CENTRAL NEBRASKA AND MOVE NORTHEAST ACROSS EASTERN NEBRASKA AND WESTERN IOWA THROUGH THE LATE AFTERNOON AND EVENING. AS WARM AND MOIST AREA RETURNS TO THE AREA…THE ATMOSPHERE WILL BE STRONGLY UNSTABLE…THIS ALONG WITH VERY STRONG SHEAR WILL COMBINE TO PRODUCE SEVERE WEATHER…SOME SIGNIFICANT INCLUDING VERY LARGE HAIL…DAMAGING WINDS AND THE POTENTIAL FOR STRONG TORNADOES.

SPOTTER INFORMATION STATEMENT…

SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT….BUT WILL BE NEEDED DURING THE LATE AFTERNOON AND EVENING ON SATURDAY.