Des Moines, Iowa – A colder shift settling into the Midwest just ahead of St. Patrick’s Day could flip part of Iowa’s incoming storm track from rain to accumulating snow between March 11 and March 17.
According to the National Weather Service Climate Prediction Center, Iowa is favored to see above-normal precipitation during the 8-14 day period, with probabilities in the 40-50% range. At the same time, temperatures across northern and central Iowa trend near to below normal. That combination raises the likelihood that stronger systems produce measurable snowfall, especially during overnight and early morning hours.
In Des Moines, Ames and Fort Dodge, nighttime lows in the upper 20s to low 30s could allow slushy accumulation on grassy surfaces and untreated secondary roads if moderate precipitation develops. Along the I-35 corridor and north toward Mason City, colder surface temperatures may support steadier snowfall. Farther south toward Ottumwa and along the Missouri border, rain remains more likely, though brief rain-to-snow transitions are possible if temperatures dip a few degrees lower.
The broader eastern United States is projected to trend wetter than normal, while California, Nevada and much of the Southwest lean drier, sharpening the west-to-east contrast in the national pattern.
Drivers across Iowa should monitor early morning road conditions, especially on bridges and overpasses where pavement cools first. Even light late-season accumulation can create slick travel. Additional updates are expected as the March 11-17 period approaches and storm timing becomes more defined.
