IEM Daily Bulletin for May 8 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 08 May 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
May 7 9:29 AM	iem,main	📝 Sundry updates per prod log review	Link
May 7 1:28 PM	iem,main	📝 Update NBM MOS retention per noaaport changes Previously, IEM was retaining 1,7,13,19 UTC MOS output. These are no longer disseminated over noaaport with v5 update, so we switch retention logic to 0,6,12,18 UTC output. closes #1616	Link
May 7 10:45 AM	iemlsr,main	⬆️ Update eslint precommit	Link
May 7 10:48 AM	iemlsr,main	🎨 Use requireElement helper	Link

Daily Feature

Relatively least humid
Date: 07 May 05:30 AM
Votes: Good: 9   Bad: 0 Abstain: 1

The start to May has seen a mix of warm and chilly days, but the lack of humidity has been consistent so far. The featured chart presents a daily climatology of humidity for Ames as expressed by mixing ratio (ratio of water to air). The top panel shows the daily range of observed values with the red line showing the 2026 values to date. The bottom panel shows the daily departure from the simple average. The start of May has seen values near the bottom of the observed range with the departure from average being the largest so far this year. Such abundant dry air is not conducive to precipitation, but the very wet April and cooler air temperatures have limited any substantial impacts so far. While the near term forecast does have precipitation chances, totals do not appear to be all that substantial.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 7 May 2026 - 12 AM 8 May 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	5	0	0	0	0	0	0	2
Svr Tstorm	28	0	0	0	0	0	0	0
Flash Flood	1	0	0	0	0	0	0	---

ARX = LaCrosse, WI DVN = Davenport, IA DMX = Des Moines, IA OAX = Omaha, NE FSD = Sioux Falls, SD

IEM Cow Report

SVR+TOR Warnings Issued:  33 Verified:  11 [33.3%]
Polygon Size Versus County Size            [30.7%]
Average Perimeter Ratio                    [15.6%]
Percentage of Warned Area Verified (15km)  [15.7%]
Average Storm Based Warning Size           [1778 sq km]
Probability of Detection(higher is better) [0.96]
False Alarm Ratio (lower is better)        [0.67]
Critical Success Index (higher is better)  [0.33]

IEMBot Social Media Posts

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