textproduct: Des Moines

KEY MESSAGES

- Dry, quiet, and generally pleasant weather through Thursday morning. Lows in the mid-40s to lower 50s tonight.

- Breezy on Thursday with some showers and storms late in the day into Thursday night. A few strong to severe storms may be possible in southern Iowa, near the Missouri border after dark.

- Warmer and more active at times from later Friday into early next week. Highs generally in the 80s each day and may touch 90 in some places. Several rounds of thunderstorms from Friday night through Monday.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 255 PM CDT Wed May 13 2026

High pressure moving across the state today has led to a beautiful day with temperatures mainly in the 70s early this afternoon under clear skies. Breezy winds have developed in much of the area ahead of the high pressure with winds out of the north-northwest sustained around 10-20 mph and gusts to 25-35 mph, but these winds have already started to decrease in western Iowa and will continue to diminish into this evening. Under the clear skies, temperatures will also fall off tonight but are mitigated from bottoming out too far with winds shifting to be out of the southeast late this evening and increasing again into Thursday morning. Temperatures will be coolest in the east closest to the high pressure where winds will remain lighter longer with lows in the 40s in the east to 50s in the west.

Thursday will start out pleasant again though winds will quickly ramp up as the pressure gradient tightens. As noted in the previous discussion, mixing is not as efficient as Monday which will keep winds from becoming too strong, but sustained winds will still be around 15-30 mph with gusts to near 40 mph, the highest winds and gusts in western Iowa. Relative humidity will also fall to around the 25-30% range with the dry conditions persisting leading to elevated fire weather conditions again, though mitigated by the green surface fuels in addition to the less efficient mixing. We could see localized blowing dust again with the higher winds Thursday, especially where any open fields were recently plowed. The wind direction may not be quite as favorable as Monday bringing dust in from the northwest, but don't want to rule out localized visibility drops near to under 1 mile with no recent rain to wet the dust.

Theta-e advection increases through the day Thursday ahead of the first in a series of impulses that will move through the region into early next week. This will start off an active period from Thursday night through the weekend and slightly beyond. CAMs all start to kick off showers in places by Thursday afternoon though looking closer at forecast soundings indicates a lot of dry air to overcome. A few showers or sprinkles with an isolated rumble of thunder may be able to reach the ground in portions of northern Iowa in the afternoon. The higher storm chances for Thursday night are in southern Iowa and late in the evening, well after dark, with the LLJ ramping up and a bigger push of theta-e advection moving through. The coverage of of these storms remains uncertain with the bulk of the activity near to just south of the IA/MO border. Should storms creep into Iowa, a few may be able to be strong to severe with hail and gusty winds in mainly far southern Iowa where limited but still present MUCAPE less than 1000 J/kg pairs with 30-40 knots of bulk shear. nd

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 255 PM CDT Wed May 13 2026

Dry but much warmer conditions are forecasted on Friday as the thermal ridge nudges closer to the area and highs surge into the 80s to potentially touching 90 in portions of southwest Iowa. Clouds and storm chances then return Friday night into early Saturday as a front moves into the state. These storms will be fighting a high pressure in the north and dry air. Models still have a fair amount of disagreement in the south in the timing and location of the next slug of theta-e advection and the LLJ is not favorably positioned. The deep moisture off the Gulf is also shunted off to the east in the low to mid levels potentially pushing the greatest storm threat to the east as conditions were looking this time yesterday, though models are also further north than they were yesterday with ballooning instability and still sufficient shear in southern Iowa. Certainly cannot rule out some strong to severe storms, but the mesoscale details remain a bit too uncertain at this point with refinements likely. The SPC does have a Marginal Risk (Level 1 out of 5) for a good portion of the area and a Slight Risk (Level 2 out of 5) in the far south/southeast on late Friday into Saturday.

The active pattern remains through the weekend with additional storm chances later Saturday into Sunday, and again later Sunday into Monday, and on Monday. SPC has all 3 of these periods (Saturday, Sunday, Monday) with a 15% risk. It is likely that what happens the previous day will somewhat dictate what happens in subsequent days. Will continue to watch these periods closely and provide additional details in the coming days. Temperatures will remain warm and at least in the 80s through the weekend. These temperatures were held down a bit from NBM with NBM on the high end of the temperature distribution and likely affected by storms and cloud debris at times.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1226 PM CDT Wed May 13 2026

VFR conditions ongoing and expected to continue through the TAF period with few clouds through the night. Winds out of the north-northwest 10-20 knots with gusts to around 25 knots will quickly diminish near to after sunset with light and variable winds through the evening before winds settle out of the southeast late tonight. Clouds and winds will then increase again Thursday morning.

DMX WATCHES/WARNINGS/ADVISORIES

None.