Tuesday, September 23, 2008

Severe Weather (Sep. 23)

The SPC has now upgraded areas of western Iowa into a slight risk of severe weather for this afternoon/evening. Moderate instability combined with fairly strong unidirectional shear will allow some thunderstorms capable of producing severe wind gusts in excess of 60 mph. Although there is also a small chance of large hail, the wind threat should be the main event.

Thunderstorm associated with last nights' convection have already entered the state and are continuing to affect portions of north-central Iowa currently. These thunderstorms should continue to move off to the east through the morning hours, and exit the state by Noon. Behind this area of showers/thunderstorms, the sky should clear allowing for sufficient heating to take place for the initiation of other thunderstorms this afternoon along the cold front. It does appear that the best threat for severe weather will be over northwest Iowa, as the best combination of shear/instability should be present there.

Additional updates are possible later this afternoon...