Gray Days for Christmas with Rain Chances Later This Week

Short-Term Forecast (Tonight through Christmas Day)

Confidence: High

This afternoon and through tonight, Iowa is experiencing a shift in weather patterns as broad upper ridging develops over the central U.S., ahead of a developing trough on the west coast. High pressure from the Dakotas and Minnesota will build southward into Iowa tonight, leading to a cool but dry evening. Clouds have been variable across the state today, with mostly clear skies in central Iowa, while northern Iowa is seeing a push of stratus clouds. This stratus is key to overnight conditions, as it will determine whether fog develops in the region.

With cloud cover expected to persist, temperatures tonight will not drop much, staying in the 20s. However, areas that remain clear could see patchy fog develop, though models vary on the timing and locations of dense fog. As a result, a low-confidence forecast is in place, but patchy fog is possible across the state overnight. Christmas Eve and Christmas Day will continue with cloudy skies, as the surface high slowly shifts east. Temperatures will be in the 30s across the state, with dry conditions for travel. While there might be a few breaks in the clouds, especially in the western parts of the state, the overall pattern will keep conditions gray for much of the holiday.

Extended Forecast (Thursday through Sunday)

Confidence: Medium

A more active weather pattern is expected to set in later this week as a broad upper trough moves out of the west. As this system advances, it will pull moisture from the Gulf of Mexico, bringing a series of rain showers to Iowa. The first round of rain will arrive Thursday night into Friday, with another round likely on Saturday.

Rainfall is expected to be moderate, with most areas seeing between 0.10" and 0.25" of rain, though the chance for more significant rainfall (0.50" or more) remains low. Despite the rain, temperatures will remain well above normal for late December. Highs will range from the mid-40s to lower 50s, with Friday and Saturday potentially seeing the warmest temperatures of the week.

The combination of increased moisture and warm temperatures for late December is quite remarkable, as 850mb temperatures will stay above 0°C across much of the country. The warmer air, coupled with moisture from the Gulf, will create the potential for several rainy days through the weekend.

Looking Ahead

While Christmas Eve and Christmas Day will remain mostly cloudy and dry, expect rain chances to return later this week. Temperatures will stay mild, with highs in the 40s and 50s, well above normal for late December. Be prepared for several rainy days from Thursday through the weekend, with moderate rainfall and potential for localized flooding. For those traveling, the dry conditions on Christmas will be a welcome relief before the rain sets in.