watch

[Perry Lester]

THE NWS STORM PREDICTION CENTER HAS ISSUED A * SEVERE THUNDERSTORM WATCH FOR PORTIONS OF NORTHERN IOWA SOUTHERN MINNESOTA NORTHEAST NEBRASKA SOUTHEAST SOUTH DAKOTA * EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 950 PM UNTIL 400 AM CDT. * PRIMARY THREATS INCLUDE... SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTHEAST OF WORTHINGTON MINNESOTA TO 30 MILES SOUTHWEST OF STORM LAKE IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES.DISCUSSION...TSTMS NOW FORMING IN SW MN ARE LOCATED NEAR/ATOP OUTFLOW BOUNDARY LEFT BY EARLIER MCS. OTHER STORMS ARE FORMING IN SE SD ALONG COLD FRONT ASSOCIATED WITH AMPLIFYING UPR IMPULSE CROSSING NRN MN. GIVEN DEGREE OF MID-LVL INSTABILITY/LOW-LVL MOISTURE PRESENT OVER REGION...AND LIKELIHOOD FOR INCREASING LARGE SCALE ASCENT AS AREA IS GLANCED BY PASSING VORT MAX...SETUP MAY YIELD A FEW STORMS WITH SVR HAIL/LOCALLY DMGG WIND...DESPITE TIME OF DAY AND RELATIVELY WEAK LOW-LVL FLOW. AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 31025. ...CORFIDI. IOWA COUNTIES INCLUDED ARE BUENA VISTA CALHOUN CHEROKEE CLAY DICKINSON EMMET HAMILTON HANCOCK HUMBOLDT IDA KOSSUTH LYON O'BRIEN OSCEOLA PALO ALTO PLYMOUTH POCAHONTAS SAC SIOUX WEBSTER WINNEBAGO WOODBURY WRIGHT . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH COTTONWOOD FARIBAULT JACKSON MARTIN MURRAY NOBLES PIPESTONE ROCK WASECA WATONWAN . NEBRASKA COUNTIES INCLUDED ARE DAKOTA DIXON . SOUTH DAKOTA COUNTIES INCLUDED ARE CLAY LINCOLN MINNEHAHA TURNER UNION YANKTON