Snow and Below-Average Temperatures Expected Through the Weekend

KEY MESSAGES

• Thursday Snow (90-100% confidence): Snow is expected, especially across central and southern Iowa, with 1-3 inches possible and locally higher amounts. The northern extent of the snow remains uncertain.

• Below Average Temperatures: Cold air will settle in through the weekend, with temperatures staying below average for at least the next week.

• Weekend System (Sunday): A large system is expected to impact the region on Sunday, with the highest snowfall amounts likely south of Iowa, but this may change. Keep monitoring the forecast.

Short-Term Forecast (Today through Thursday)

Confidence: High

Iowa is seeing colder air move in as northwest winds bring dry, cool conditions. Wind gusts of up to 30 mph will continue through the morning hours, especially in the northern and eastern parts of the state. Despite breaks in the clouds, temperatures will remain cold, with highs only in the 20s and 30s.

Tonight, cloud cover will increase as a clipper system moves in from the Pacific Northwest. The system is expected to bring snow, with amounts ranging from 1 to 3 inches across central Iowa. While there’s a high degree of confidence in the general snow forecast, localized snowfall amounts may be higher, particularly along the I-80 corridor. Several factors, including vertical motion, instability in the dendritic growth zone (DGZ), and potential for higher snow ratios, could lead to increased snowfall in certain areas. Some models are showing potential for snow amounts of 3-4 inches in localized areas.

Extended Forecast (Friday through Sunday)

Confidence: Medium

As snow from Thursday night clears out, the colder temperatures will become more pronounced, with highs for the weekend expected to drop into the teens. The biggest concern beyond Thursday is the large system expected on Sunday. Ensemble guidance shows that the highest snowfall amounts may be focused on areas south of Iowa, with parts of northern Missouri and eastern Iowa seeing the heaviest snow. Around 40% of model members suggest more than 4 inches of snow for far southern Iowa, but there is still significant uncertainty regarding the system's exact track and intensity.

Currently, snowfall amounts are forecast to be moderate, but the potential for higher snow totals remains as snow ratios could exceed 10:1. Confidence in exact snowfall amounts remains low (around 20%), and the forecast will need to be monitored as we get closer to the event.

Looking Ahead

A major shift in weather patterns is expected to take place next week, with an upper-level low settling over the Great Lakes region, bringing an extended period of below-average temperatures. Highs will remain in the teens, with lows approaching zero, making for a prolonged cold snap. Snow from the weekend system could add to the cold, but the focus will be on frigid temperatures that could last through the workweek.

Flurries, Gusty Winds, and Snow Chances Ahead

KEY MESSAGES:

Today: Light snow and rain south of Interstate 80, with temperatures hovering around freezing. Some slick spots on roads are possible due to slush, but accumulation on grassy surfaces will be minimal.

Thursday: Snow is expected, primarily in central and southern Iowa, with potential for advisory-level snowfall. Travel impacts are possible during the day.

Colder Weather: Winter conditions will take hold starting Thursday, with temperatures dropping into the teens by early next week. Snowfall amounts and winter weather impacts are still being monitored.

Short-Term Forecast (Today through Wednesday)

Confidence: Medium

A 500mb low pressure system has continued to deepen overnight, bringing precipitation to Iowa, primarily focused along and south of Interstate 80. As the system moves east, rain and snow will continue to shift southeast, with temperatures hovering around freezing through the morning in the southeast. Although the melting layer is shallow, temperatures are warm enough to limit accumulation on grassy surfaces. However, roadways could still be slick due to slush, and localized higher amounts of snow are possible along a deformation axis forming over eastern Iowa.

Throughout the afternoon, gusty winds up to around 30 mph will accompany light flurries. Cold air advection (CAA) will steepen lapse rates in the planetary boundary layer (PBL), contributing to the flurries, but due to shallow saturation and subsidence, snowfall will remain light. The gusts will decrease quickly as cloudiness dwindles, and we can expect clearing skies in the western parts of the state. Temperatures will remain near freezing for much of the day, with lows expected to drop into the teens in the northern and western areas overnight due to radiational cooling.

Thursday and Beyond: Snow and Winter Conditions

Confidence: Medium to High

The next significant weather system arrives Thursday, bringing snow primarily to central and southern Iowa. This time, temperatures will be cold enough to ensure snow as the primary precipitation type. Lift is expected to maximize in the mid-morning to midday hours, with around 50% of ensemble members predicting at least 1 inch of snow for the day. There are factors that could lead to higher snowfall amounts, especially due to the magnitude of forcing and its overlap with the dendritic growth zone (DGZ). Forecasts suggest the potential for advisory-level snowfall in a narrow band, and this will need to be closely monitored. Travel impacts are likely, especially during the daytime on Thursday.

After Thursday’s snow event, colder winter conditions will settle in. An energetic trough from the Pacific Northwest will dive southeastward, bringing colder temperatures to the region. Although deterministic models are trending southward with snowfall forecasts, it’s important to monitor the forecast closely as this system develops. Iowa may experience some winter weather impacts, though the exact details are still uncertain.

Looking Ahead

As we move into early next week, an upper-level closed low will descend upon the Great Lakes region, ushering in even colder air from an Arctic high in Canada. Highs are expected to drop into the teens early next week, with cold temperatures likely sticking around through at least the rest of the workweek. Snowfall from the weekend system will be more confined to the southern parts of the state, but overall winter conditions are set to take hold, with the potential for snow and other winter weather impacts to be monitored closely.

Stay informed as the weather continues to evolve, especially as we approach Thursday’s snow event and the colder temperatures expected next week. Be prepared for slick roads, gusty winds, and winter weather impacts as the season settles in.

Grey Skies: Clouds, Drizzle, Weekend Rain Ahead

Current Conditions: A Blanket of Clouds

A vast stratus field stretches across the region, leaving Iowa under thick, gray skies. The overcast layer extends as far as the northern Ozarks and central Nebraska, with no clearing anticipated until at least Saturday. A small break in the cloud cover is visible over parts of southern and eastern Wisconsin, but for Iowans, it’s cloudy weather all the way.

Drizzle and Mist on the Horizon

As southwest winds slowly pull more moisture into the region tonight through Thursday night, expect intermittent light drizzle and mist to develop.

Temperatures: Generally at or above freezing, reducing concerns about icy conditions.

Exceptions: A low probability (<20%) exists for temperatures to remain below freezing in northeast Iowa late tonight or early Thursday morning, which could cause brief slick spots if drizzle develops.

Fortunately, precipitation amounts will be minimal—less than a hundredth of an inch—and significant impacts are not anticipated.

Friday: Rain Returns

By Thursday night, a low-pressure system will move into eastern Oklahoma, later tracking over Missouri and interacting with a second, deeper trough. For Iowa, this means:

Rain Chances: The first wave of rain will arrive Thursday night, with a second, more prolonged round lasting through Friday and into Friday night.

Temperatures: Above freezing, so all precipitation should fall as rain.

Rainfall Totals: Light, around 0.25–0.33 inches overall.

While impacts will be minimal, the period will feel damp and gloomy, so plan accordingly for a wet end to the workweek.

Weekend Respite?

The weekend could bring a brief break as the late-week trough exits to the east. With high-pressure influence and zonal steering flow, clearing skies are possible, but low-level flow remains uncertain. Don’t pack away your rain gear just yet.

Looking Ahead: Next Week’s System

Early next week, a stronger 500 mb shortwave is expected to move out of the Rockies, deepening over the Midwest by Monday. However, the track of this system remains uncertain:

GFS Model: Brings the system directly over Iowa, increasing precipitation chances.

EC Model: Tracks it further south over Missouri and Arkansas, leaving Iowa mostly dry.

GEM Model: Offers a compromise, suggesting partial precipitation over southern Iowa.

For now, expect 20–40% precipitation chances over southern Iowa Monday into Monday night, with more details as model consensus improves.

What to Keep in Mind

Drizzle and Mist: Minimal but persistent tonight through Thursday night.

Rain: Expect a soggy Friday, though impacts will be low.

Weekend: A potential for clearing skies, though uncertainty remains.

Early Next Week: Stay tuned for updates as the next system approaches.

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.