textproduct: Des Moines

KEY MESSAGES

- Warming trend continues Sunday and lasts for much of Christmas week.

- Low chance (<20%) of light precipitation Wednesday, but otherwise dry.

- Fog potential exists for snowpacked areas in northern Iowa through the week.

DISCUSSION

Issued at 159 PM CST Sat Dec 20 2025

Gusty winds followed the front this afternoon, mainly in the north. Its influence was felt less in southern and southwest Iowa where temperatures could still recover into the 40s. The surface high mentioned previously has trended more west in track, influencing more of the state tonight, meaning lows will be cooler. Southwest flow invades right at sunrise Sunday and recovers highs close to where they were today. Boosted highs to the 90th percentile as highs have outperformed in this warm, dry regime the past few days. Northeast Iowa will remain on the cooler side due to the extended influence of the high. Southwest flow continues Sunday night which will keep southwest Iowa above freezing. A push of theta-e advection will spawn clouds and perhaps some precipitation along its leading edge for far northern Iowa, but precipitation chances are very low (<10%). Condensation pressure deficits will decrease with time within the cloud layer, but the better chance of drizzle forming is over eastern Iowa, at this time. Snowmelt will take place as skies clear Monday afternoon. Wet bulb temperatures will rise above freezing in northern Iowa and, given overperforming trends this weekend, they could be higher than currently forecasted, increasing snowmelt. Fog chances start entering the picture at this point.

Upper level ridging continues to favor a warming trend for next week and as mentioned in the previous discussion, there are some challenges for highs in northern Iowa this week. Notice the temperature spread, for example, on Tuesday. High pressure will slide across the Upper Midwest and introduce northerly flow in northern Iowa. Paired with remaining snow pack, it justifies temperatures staying in the 30s. Another window for stratus (and perhaps some drizzle) arrives with the next push of moisture on Wednesday. Summing up probabilities by the time Christmas day rolls around, ensemble guidance has >50% of at least 70% cloud cover in northern and eastern Iowa for almost all of Tuesday-Thursday. With this in mind, the warmup for this portion of the state will be limited, but record highs still look to be challenged across central and south by Christmas.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1059 AM CST Sat Dec 20 2025

VFR cloud deck pushing off in the next 6 hours, leaving FEW to SKC for the remainder of the period. Winds will become light to variable after 00z and shift to southerly through the morning hours.

DMX WATCHES/WARNINGS/ADVISORIES

None.