textproduct: Des Moines

KEY MESSAGES

- Mostly well above temperatures throughout the 7 day forecast.

- Light rain and snow chances (20 to 30%) return late tonight and Thursday morning over north central into central Iowa. Minor snow accumulations are possible.

UPDATE

Issued at 313 AM CST Wed Feb 11 2026

Dry air remains a primary issue with precipitation late tonight into Thursday, both at the surface and now in the mid- levels. Some newer guidance isn't overly convinced that there will be enough lift or moisture over the area to produce precipitation, which is pulling NBM probabilities down near or below 15% (ie a dry forecast). Similarly, the small spatial area of the band and uncertainty of it's placement, is causing values to be smoothed out and reduced. However, with the rest of guidance still showing at least some push of mid-level moisture and ~5 to 10 microbars of lift, not buying the completely dry forecast quite yet. What seems more likely is that most of the area will remain dry, but a narrow swath of light precipitation will punch through where lift and moisture are maximized. There will still be dry air to overcome within this band, so QPF values are still light, but not convinced precipitation chances are zero quite yet. There has also been a recent southeastward trend in the precipitation placement since this time last night, suggesting it may pass more through north central into central Iowa, rather than far northern and northeastern Iowa.

The new precipitation forecast reflects these trends. Have increased the NBM precipitation chances to around 20 to 30% over central and north central Iowa from 05z to 18z Thursday morning. Have also maintained the rain/snow mix, given wetbulb temperatures in the bottom ~2k feet on either side of 0C. Rain vs snow will likely be driven by local rates and temperatures, as indicated in the previous discussion below. Fortunately, with the drier trend, the QPF has also decreased quite a bit and the likelihood of significant snowfall accumulations appears low.

DISCUSSION

Issued at 242 PM CST Tue Feb 10 2026

Large area of high pressure is moving into the South Dakota and Nebraska this afternoon and this has led to the thinning of the stratus cloud layer over northern Iowa. Much of this stratus has become more cellular as mixing and subsequent layer drying has occurred. Mostly static weather the next 30-36 hours as the high pressure moves across Iowa tonight and Wednesday before passing to the east Wednesday night. The lack of snow cover and dry conditions over Iowa will again result in temperatures well above normal on Wednesday despite the lack of any warm advection. Ample sunshine will provide good insolation for heating prior to high level clouds arriving late in the day over the west. Expect high temperatures in the 40s to low 50s Wednesday.

Modest moisture/theta-e advection will begin to stream back north on the backside of the departing high Wednesday night and in advance of an approaching short wave dropping through the northwest flow. Precipitation chances and type are the primary challenge here from 06z-18z Thursday. First saturation of the departing very dry airmass will be an initial challenge. At this time, sufficient forcing from kinematic and thermal dynamic processes within a moistening layer looks sufficient for a vast amount of hydrometeorgenesis. Assuming this does occur, hydrometeor loading of the dry layer below the 5-6 kft cloud bases, should be sufficient saturation for the precipitation to reach the surface. Therefore, increase precipitation chances over NBM, which was much less. Precipitation type is dependent on a near surface warm layer and this case, due to a spread in the temperature and dew points near surface which maybe artificially inducing melting in some solutions. Assuming the hydrometeor loading of sub cloud base, this will lead to cooling and temperatures and dew points converging on the near to below freezing wetbulb temperatures. In that scenario, this also would produce more snow than rain which could result in the light accumulations over northern Iowa. Given the forcing parameterizations, the precipitation may be more showery as opposed to stratiform so local one inch amounts are possible.

Beyond Thursday, the upper flow will transition to more westerly/zonal flow, which is mild this time of year, again especially with no snow cover. A closed low is still expected to move across the Southern Plains this weekend while a short wave passes north of the state. That northern short wave will limit the northward extent the southern system can lift and is leading to the diminishing precipitation chances. Ridging will occur by Monday followed by strong southwest flow, which should be even warmer flow provided that a mass stratus shield doesn't develop. The current day 7 has a return to 60 degrees for parts of central and southern Iowa while there will be lots of 50s Thu-Mon.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 524 AM CST Wed Feb 11 2026

VFR conditions prevail and will continue through the period. Scattered stratus upstream has generally been dissipating as it progresses southward and likely won't reach TAF sites before dissipating through the day. Winds will remain light out of the west today, then become more southerly and variable overnight tonight. Mid-level clouds then begin to fill in from the west this evening.

DMX WATCHES/WARNINGS/ADVISORIES

None.