textproduct: Des Moines

KEY MESSAGES

- Relatively warm and dry conditions last through today and tomorrow.

- Some chances for precipitation (up to 40%) and gusty winds Wednesday into Thursday.

- A cooling trend with sub-freezing morning lows possible Thursday through end of the week.

SHORT TERM /THROUGH TUESDAY/

Issued at 222 AM CST Mon Nov 9 2026

A surface to 850mb trough is working its way across the Dakotas this morning visible on both mesoanalysis and water vapor imagery. Winds in the low to mid levels are being accelerated just ahead of this trough out of the southwest which will come into play later this morning. For the time being, a ridge sits over Iowa and the pressure gradient is still weak. Low level winds are generally 5 knots or less across most of Iowa and cirrus is really only impacting the northern third of the state so efficient radiative cooling is underway. Some patchy river valley fog may develop over the next few hours, especially in southeast Iowa. However, the window for fog formation is closing as cirrus advances south and winds begin to increase just prior to sunrise from the approaching shortwave.

As the shortwave approaches, low level warm air advection from the southwest will increase this morning. Highs yesterday overperformed under clear skies and the addition of advection today may allow for temps a couple degrees higher. NBM may perform well in the north this afternoon where cirrus will continue to stream in, but have increased highs several degrees above NBM central and south to better match bias corrected models. Even REFS, which, like HREF used to do, has been underdoing highs by ~5 degrees on this stretch of fall clear sky days, and brings highs into the mid 60s central/south today.

There is some valley fog potential once again Tuesday morning but cirrus may linger and winds may not fully calm until the arrival of the high pressure center after 12z. So it is unlikely that fog will be any more prevalent than this morning. High pressure again sits over the state through the day Tuesday and allow for another seasonably warm day. However, temps will likely be a few degrees cooler due to more widespread cirrus per REFS.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/

Issued at 150 PM CST Sun Nov 8 2026

Ensemble and longer range guidance continues to signal a longwave trough expanding over the central and eastern US through the middle of the week. Deterministic models are becoming confident in a shortwave trough sweeping through the state early Wednesday morning as this change in the weather pattern is ushered in. The associated surface low carries precipitation (15-30% chance) and gusty winds with it, but the exact magnitude, timing, and track of the low are still fairly uncertain at this time. Given temperatures cooling Wednesday night through Thursday, the potential for wintry precipitation is not out of the question. The rest of the week continues this cooling trend as northerly winds amplify cold air advection into the area.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1133 PM CST Sun Nov 8 2026

VFR conditions expected to prevail. Satellite shows midlevel clouds coming into northern Iowa. Some river valley fog was noted at FXY, which would be the extent of fog tonight. It will be limited due to the cloudiness, especially for northern terminals. Southwesterly winds expected through the daytime tomorrow and a wind shift will usher in northwest flow after 20z. Winds will decrease behind the wind shift.

DMX WATCHES/WARNINGS/ADVISORIES

None.