FXUS63 KDMX 190340

AFDDMX



Area Forecast Discussion

National Weather Service Des Moines IA

1040 PM CDT Wed Mar 18 2026



 ...Updated for the 06z Aviation Discussion...



.KEY MESSAGES...



- Fog and stratus across northern Iowa tonight into Thursday.

  Fog over snow-packed areas could become dense.



- Warming trend continues into the weekend, topping out on

  Saturday with highs in the 80s.



- Brief cooldown on Sunday with recovering temperatures to start

  next week. Forecast looks largely dry, at this time.



&&



.SHORT TERM /THROUGH FRIDAY NIGHT/...

Issued at 232 PM CDT Wed Mar 18 2026



Warmth and moisture are arriving from the west this afternoon with 

dew points above freezing melting much of the snowpack in Iowa. 

There's potential for snowpack to stick around in northern Iowa 

where the depth is higher, leading to areas of fog tonight. Dew

points will remain above freezing overnight, which could create

dense fog above the freezing surface of snow. Highest 

confidence is in Minnesota where the snowpack is thicker.



Wester CONUS ridging will continue to chew away at the 

northwest flow in the Upper Midwest. More of the thermal ridge's

influence will be felt by Friday as +15C 850mb temperatures 

come into southwest Iowa, boosting highs into the 70s. As for 

northeast Iowa, the moisture from the melting snowpack may lead 

to stubborn cloud cover, hence the down trend in highs. A wave 

will pass Thursday night, but the dry profile will limit its 

effects to just a wind shift.



&&



.LONG TERM /SATURDAY THROUGH WEDNESDAY/...

Issued at 232 PM CDT Wed Mar 18 2026



Southwest flow resumes Saturday and highs benefit from the 

WAA. Highs in the 80s will be common in the southwest half of the 

state, quite a change from the single digit lows earlier this week!



A front will arrive sometime Saturday night or Sunday which will 

drop highs back towards average to end the weekend. Precipitation 

chances with this boundary are low (<10%) as better saturation depth 

isn't achieved until the boundary passes southeast of the state. 

Ridging will start to recover next week with Iowa residing in the 

northwest flow. The amplified pattern will eventually shift, leading 

to another pattern change to cooler weather for Iowa in the second 

half of next week.



&&



.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...

Issued at 1036 PM CDT Wed Mar 18 2026



Fog remains the aviation forecast challenge later tonight and

Thursday morning. Wind speeds are staying a bit higher than

previously expected and combined with passing mid-level

cloudiness may limit the fog. Therefore, backed off fog impacts

a bit over northern Iowa though a period of MVFR or lower fog

remains possible, especially at KMCW. VFR conditions are

expected to persist at KDSM/KOTM. The wind will be variable in

wind direction at times and will remain below 12 kts.



&&



.DMX WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



SHORT TERM...Jimenez

LONG TERM...Jimenez

AVIATION...Donavon