IEM Daily Bulletin for May 13 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 13 May 2026

News

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Title: ISU Network Issue
Date: 12 May 11:06 PM
Author: Daryl Herzmann
link

Since about 6 PM 12 May 2026, Iowa State has been having Domain Name Service (DNS) outages impacting various IEM data flows and services. Things stabilize and then go back down hill with the most recent outage ending at about 11 PM 12 May 2026. Will continue to monitor and whack-a-mole problems encountered. Thanks for your patience.

IEM Code Pushes <repo,branch> on Github

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Daily Feature

30 Percentage Points Progress
Date: 12 May 05:30 AM
Votes: Good: 11   Bad: 0 Abstain: 0

It has been a rather strange start to the growing season. The month of April was quite warm and wet, leading to an early start to the growing season with plenty of growing degree days accumulated prior to the start of May. May has now started off rather dry with low humidity levels allowing overnight temperatures to cool below freezing over a number of days so far this May. USDA NASS released their weekly crop progress report yesterday and estimated 72% of Iowa's corn crop having already been planted, a 30 percentage point increase over the estimate last week thanks to the mostly dry start to May. The featured chart looks into the weekly percentage point change in crop planting pr ogress as estimated by NASS. The left hand labels show the year and the maximum weekly change value for each year. A 30 percentage point change is about at the middle of possible yearly maximum values.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 12 May 2026 - 12 AM 13 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	8	0	0	0	0	0	0	0
Flash Flood	4	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:  10 Verified:   3 [30.0%]
Polygon Size Versus County Size            [13.6%]
Average Perimeter Ratio                    [23.7%]
Percentage of Warned Area Verified (15km)  [20.7%]
Average Storm Based Warning Size           [504 sq km]
Probability of Detection(higher is better) [1.00]
False Alarm Ratio (lower is better)        [0.70]
Critical Success Index (higher is better)  [0.30]

IEMBot Social Media Posts

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