PUBLIC SEVERE WEATHER OUTLOOK
STORM PREDICTION CENTER NORMAN OK
12 NOON CDT SAT JUNE 5 1999

...OUTBREAK OF SEVERE THUNDERSTORMS INCLUDING A FEW STRONG TORNADOES EXPECTED OVER PARTS OF THE NORTHERN AND CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY LATE THIS AFTERNOON AND TONIGHT...

THE STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE DEVELOPMENT OF SEVERE THUNDERSTORMS WITH A FEW STRONG TORNADOES... LARGE HAIL AND DAMAGING WINDS OVER PARTS OF THE NORTHERN AND CENTRAL PLAINS LATE THIS AFTERNOON AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE:
CENTRAL AND EASTERN NEBRASKA
SOUTH CENTRAL AND EASTERN SOUTH DAKOTA
SOUTHWEST MINNESOTA
WEST IOWA

LOW PRESSURE OVER WEST CENTRAL NEBRASKA WILL DEEPEN THIS AFTERNOON AS AN UNSEASONABLY STRONG UPPER AIR DISTURBANCE OVER THE SOUTHERN PLATEAU LIFTS NORTHEASTWARD ACROSS THE CENTRAL PLAINS. AS THE LOW MOVES INTO SOUTH DAKOTA TONIGHT A WARM FRONT WILL LIFT NORTHWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND A COLD FRONT/DRY LINE WILL ADVANCE EASTWARD OVER THE CENTRAL AND SOUTHERN PLAINS. IN ADDITION...A SURFACE BOUNDARY GENERATED BY EARLY MORNING THUNDERSTORMS OVER THE NORTHERN PLAINS MAY PROVIDE ANOTHER FOCUS FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON. STRONG SOUTHERLY WINDS OVER THE PLAINS STATES WILL ALLOW WARM HUMID AIR TO RETURN INTO PARTS OF NEBRASKA...SOUTH DAKOTA...AND SOUTHERN MINNESOTA TODAY.

THIS WILL CONTRIBUTE TO THE FORMATION OF A VERY UNSTABLE AIR MASS AND INCREASE THE LIKELIHOOD OF SEVERE THUNDERSTORMS. THE STORMS ARE EXPECTED TO DEVELOP RAPIDLY DURING THE LATE AFTERNOON AND EVENING HOURS OVER NEBRASKA AND SOUTH DAKOTA...THEN SPREAD EASTWARD AND NORTHEASTWARD INTO PARTS OF MINNESOTA AND IOWA TONIGHT. AS A VERY STRONG UPPER LEVEL JET STREAM MOVES NORTHEASTWARD INTO THE CENTRAL AND NORTHERN PLAINS THE VERTICAL WIND PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR SEVERE THUNDERSTORMS...INCLUDING THE POSSIBILITY OF STRONG TORNADOES.

THIS IS POTENTIALLY A VERY DANGEROUS SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO RADIO AND TELEVISION AND NOAA WEATHER RADIO FOR SEVERE WEATHER WATCHES...WARNINGS AND STATEMENTS THIS AFTERNOON AND TONIGHT.