Sunday, February 8, 2009

Rain & Thunderstorm!?

We will undoubtedly see our first rain of the year across the state on Monday, but a mix of winter weather may be in store for the northern third tonight. And the entire state returns to a chance of winter precipitation for Tuesday night and Wednesday as the next storm system arrives...

The state has seen temperatures in the 40s and 50s, even a few 60s the past couple of days which has allowed a considerable amount of snow melt. This snow melt combined with ice jams has created some flooding concerns across the state, with an increased chance of flooding for early this week as rain moves into the forecast. A storm system will begin to effect the state tonight as moisture moves into the lower and mid-levels. Scattered sprinkles or showers are possible tonight across the state, with the northern third seeing the risk of these showers/sprinkles freezing upon contact with the surfaces as temperatures drop below freezing. Ice accumulations is not likely, especially as any freezing rain should last only a few hours before turning into rain showers. Expect showers to become widespread by the morning hours across much of western Iowa, with these showers and thunderstorms working through the rest of the state by evening. Given the strong dynamic storm system, some instability is expected to combine with strong speed shear and low level wind shear to create the potential for a few severe thunderstorms. The main threats appear to be strong winds and maybe a few hailstones. After lows tonight ranging from 30 to 40 degrees from northeast to southwest, expect highs on Monday from the upper 40s to upper 50s from north to south. The showers and thunderstorms may continue over the northern half of the state Monday night, with lows from the mid 30s to mid 40s from northwest to southeast.

A drastic warm-up on Tuesday just ahead of the next storm system, temperatures should range from the mid 40s to mid 60s from northwest to southeast. Tuesday night lows from the mid 20s in northwest Iowa to near 40 in the southeast corner of the state. The southeast half of the state may also see some rain showers during the overnight. Light precipitation should continue on Wednesday over much of the state, with high temperatures in the mid 30s to mid 40s and falling, some mixed precipitation of rain/snow is possible. We'll see this round of precipitation move out as temperatures fall Wednesday night into the upper teens to upper 20s across the state.

A late night update is possible to address the potential for severe thunderstorms on Monday for Iowa...