The SPC is forecasting ...severe thunderstorms expected over parts of the central plains into the upper mississippi valley later today and tonight.... Please read the latest public statement about this event.
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SPC AC 071558 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1058 AM CDT SAT JUN 07 2008 VALID 071630Z - 081200Z ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT ACROSS PARTS OF EASTERN NEB...MUCH OF IA...SOUTHEAST MN...SOUTHWEST WI...AND NORTHWEST IL... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL PLAINS INTO MUCH OF THE GREAT LAKES REGION... ...IA/MN/WI/IL/LOWER MI... MORNING WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH MOVING ACROSS EASTERN NEB INTO WESTERN IA. THIS FEATURE WILL AFFECT PARTS OF IA/SWRN WI/NWRN IL THROUGH MUCH OF TODAY AND THIS EVENING...RESULTING IN AN ACTIVE SEVERE WEATHER EPISODE FOR THE REGION. THUNDERSTORMS ARE CURRENTLY AFFECTING PARTS OF SOUTHEAST MN AS STRONG LOW LEVEL WARM ADVECTION MAINTAINS STORMS ON NOSE OF SOUTHERLY LOW LEVEL JET. STRONG HEATING OVER NORTHEAST IA WILL LIKELY LEAD TO FURTHER DEVELOPMENT INTO THAT AREA BY LATE MORNING/ EARLY AFTERNOON. THEN...BY MID AFTERNOON...MORE WIDESPREAD THUNDERSTORM DEVELOPMENT IS LIKELY ACROSS THE BULK OF IA AS SHORTWAVE TROUGH ENHANCES LIFT AND FURTHER WEAKENS CAP. VERTICAL SHEAR PROFILES OVER THE AREA SHOW FAVORABLE LOW LEVEL VEERING/INCREASING WITH HEIGHT AND PARAMETERS FAVORABLE FOR SUPERCELL DEVELOPMENT. FORECAST SOUNDINGS INDICATE MLCAPE VALUES OF 3500+ J/KG AND RATHER LOW LCL VALUES SUGGESTING A RISK OF TORNADOES /SOME STRONG/...ALONG WITH DAMAGING WINDS AND HAIL. THESE STORMS WILL SPREAD INTO PARTS OF WI/NWRN IL DURING THE EVENING. IF ACTIVITY CAN MAINTAIN ORGANIZATION...PARTS OF LOWER MI MAY BE AFFECTED OVERNIGHT AS STORMS CROSS LAKE MI. ...NEB/IA TONIGHT... FARTHER WEST...EASTERN NEB WILL BE UNDER SHORTWAVE RIDGING THROUGH MUCH OF THE AFTERNOON IN WAKE OF TROUGH MOVING INTO IA. HOWEVER...STRONG DAYTIME HEATING WILL ALLOW CONVECTIVE TEMPERATURES TO BE REACHED AND LIKELY RESULT IN SCATTERED AFTERNOON THUNDERSTORMS ALONG SURFACE BOUNDARY OVER SERN NEB. SLIGHTLY VEERED LOW LEVEL WINDS LESSENS CONFIDENCE IN AN ENHANCED TORNADO THREAT...BUT DAMAGING WINDS AND HAIL WILL BE LIKELY. LATER TONIGHT...STRONGER FORCING IS EXPECTED TO OVERSPREAD REGION AS NEXT UPSTREAM SHORTWAVE TROUGH APPROACHES. THERE IS CONSIDERABLE MODEL CONSISTENCY IN SUGGESTING THE DEVELOPMENT OF A LINEAR MCS EMERGING FROM CENTRAL NEB AND TRACKING INTO HIGH INSTABILITY AIRMASS. THIS MAY RESULT IN AN ORGANIZED/WIDESPREAD WIND EVENT FROM EASTERN NEB INTO WESTERN/CENTRAL IA OVERNIGHT. ..HART/JEWELL.. 06/07/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z