IOWA -- A Winter Storm will impact Iowa tonight. Travel conditions will go downhill first across Northwest Iowa.
A Winter Storm Warning and Winter Weather Advisory is in place for much of the NW half of the state through noon on Wednesday. Heavy snowfall will occur overnight in that part of the state. Snowfall rates of 1 to 2" an hour are possible with an isolated thundersnow report possible. The winds will pick up from the northwest at 25 to 35 mph and gusts to 50 mph. Blizzard conditions may be possible. Rain and thunderstorms will continue during the evening in the Des Moines Metro and through southern and southeast Iowa.
Early Morning Wednesday - Snow will be ending by 9 AM. The heaviest snow is expected near Spencer. Dry air will work its way into south-central and southeastern Iowa. As the air gets colder some light wrap around snow may move through Des Moines before 6 AM, but only a dusting is expected. Winds will stay gusty through the morning.
Wednesday - The winds will be strong from the northwest from 25 to 35 mph and gusts up to 50 mph. Blowing snow may be a problem keeping travel difficult with poor road conditions and low visibility in northwest Iowa.
Low pressure will deepen as it moves northeast through Iowa and strengthen with precipitation intensifying around it with rain out ahead from southern Iowa into Wisconsin, and snow on the northwest side of the low with the colder temperatures.
The highest snowfall rates in northwest Iowa will occur this evening through midnight. Eventually, the coldest air will wrap in and around the low and bring colder air by early Wednesday morning and a few snowflakes through the Metro. But no accumulation is expected much more than a dusting for the Des Moines area.
The winds will stay strong on Wednesday and even when the snow has lifted off to Wisconsin, blowing snow will stay a problem with poor visibility and blowing and drifting of snow.
Late Week Weather
More active weather will move in for the end of the week. Thanksgiving brings some light snow in the evening with a weak disturbance moving through the Central US. A warmer storm system pushes in on Friday. This will bring primarily rainfall to much of Iowa through the afternoon and evening on Friday. Temperatures will rise to the low to mid-40s into the evening and overnight. Saturday will start warm with temperatures even reaching near 50 degrees with rain continuing most of the day. Cold air wraps back in with some light snow on Sunday.