textproduct: Des Moines

KEY MESSAGES

- Hot and humid conditions continue through the weekend, with heat indices nearing 100 degrees each day.

- Low (~20%) thunderstorm chances return this afternoon and evening, and again on Friday. The threat of severe weather remains low.

SHORT TERM /THROUGH FRIDAY/

Issued at 134 AM CDT Thu Jul 16 2026

A deep-layer ridge continues to dominate Iowa weather, but will begin to reorient itself just a bit over the next couple days. At 500 MB, the ridge currently stretches from the Midwestern U.S. east southeastward to the mid-Atlantic coast around Virginia and North Carolina. A slight weakness with minimally enhanced vorticity is creeping across portions of Arkansas and Missouri at the current time, and will pinch off the ridge and drift toward southern Iowa by tonight, then eastward into Illinois on Friday. Concurrently, the surface ridge that has blanketed Iowa for the last few days will slowly begin to retreat eastward. The sensible effects of this general scenario will be twofold. First, the nearly calm winds we have seen for days will finally pick up just a bit from the south southwest by tonight and Friday, but still remain light at less than 10 MPH. Second and more notably, the area of weak vorticity and deeper moisture over Missouri will bring a return of low (20%) thunderstorm chances at times from this afternoon into Friday. Given the very weak ambient flow, this will be typical mid- summer "popcorn" storms that will pulse up and down quickly and carry a minimal severe weather threat. Have maintained isolated thunderstorms in the forecast across much of the area this afternoon and evening, and again on Friday.

Aside from the return of isolated thunderstorms and a light breeze, heat and humidity will continue through the end of the week. Dewpoints will increase slightly today as the moisture moves in from Missouri, however, scattered clouds may also suppress temperatures just slightly. The net effect will be little chance in Heat Index values, which will still peak generally in the upper 90s each day. The good news is that the smoke from Canadian wildfires, which is having significant impacts in parts of the Great Lakes region, is still expected to remain northeast of our area, to the north of the 500 MB ridge.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 217 PM CDT Wed Jul 15 2026

Over the weekend, the ridge which has been over the region will continue to break down as the high weakens, putting us on the periphery of it through the weekend and into early next week. The most notable feature currently in the long term forecast is the potential for a shortwave to affect the region Sunday night into Monday which could lead to shower and thunderstorm potential returning to the area. At the same time, LREF ensemble clustering shows the ridge may continue to hold out which would lead to a higher potential farther to the east. At this point, it's too far out to try and pinpoint a location. Otherwise, warm and humid conditions continue before the ridge breaks down further, bringing some amount of relief from the heat during the early part of the workweek.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 623 AM CDT Thu Jul 16 2026

Patchy, shallow fog early this morning will burn off by around or just after 12Z. Thereafter, VFR conditions are forecast with light winds and mostly clear skies. A few small thunderstorms will be possible later today, roughly between about 18Z and 02Z, however, coverage will be so isolated that the probability of impact at any given terminal is far too low for a TAF mention at this time.

DMX WATCHES/WARNINGS/ADVISORIES

None.