IEM Daily Bulletin for May 9 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 09 May 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
May 8 7:38 PM	iem,main	✨ Support IEM product_id fields with -BBB included	Link
May 8 7:41 PM	iem,main	📝 Sundry updates per log review	Link
May 8 8:24 PM	iem,main	💚 Address codereview and CI failure	Link

Daily Feature

Afternoon mid-60s
Date: 08 May 05:30 AM
Votes: Good: 7   Bad: 1 Abstain: 0

Temperatures were rather pleasant on Thursday with mid 60s common over much of Iowa during the afternoon hours. Ames reported a temperature of 66°F at 3 PM. The featured chart looks into the frequency of having such a temperature by month for Ames. The bars present the frequency of having a temperature within the inclusive range of 63 to 67°F at 2 PM LST (3 PM CDT) with the blue dots showing the frequency below that range and red dots above. May does have the highest frequency of such temperatures, but only by a slim margin to April. It is kind of interesting to denote the near identical frequencies between February and July!

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 8 May 2026 - 12 AM 9 May 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	2	0	0	0	0	0	0	0
Svr Tstorm	117	0	0	0	0	0	0	2
Flash Flood	6	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: 112 Verified:  45 [40.2%]
Polygon Size Versus County Size            [22.2%]
Average Perimeter Ratio                    [19.5%]
Percentage of Warned Area Verified (15km)  [21.3%]
Average Storm Based Warning Size           [1373 sq km]
Probability of Detection(higher is better) [0.95]
False Alarm Ratio (lower is better)        [0.60]
Critical Success Index (higher is better)  [0.39]

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