IEM Daily Bulletin for Jun 30 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 30 June 2026

News

No news is good news

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Daily Feature

Steamy Sunday
Date: 29 Jun 05:30 AM
Votes: Good: 15   Bad: 0 Abstain: 0

Outside of a rain cooled area of northeastern Iowa, Sunday was steamy for the rest of Iowa with heat index values reaching the warmest values to date in the upper 90s and 100s. The featured map presents IEM computed maximum heat index values from the airport weather stations. More of the same is expected for the rest of the week, but like what happened over northeastern Iowa on Sunday, thunderstorm complexes can take a significant bite out of afternoon heat. These complexes are difficult to forecast days in advance and with ample heat and humidity around, they have the ingredients to persist over longer than expected periods of time.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 29 Jun 2026 - 12 AM 30 Jun 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	19	0	0	0	0	0	0	2
Svr Tstorm	164	0	0	0	0	12	1	6
Flash Flood	9	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: 176 Verified:  81 [46.0%]
Polygon Size Versus County Size            [26.6%]
Average Perimeter Ratio                    [23.2%]
Percentage of Warned Area Verified (15km)  [18.6%]
Average Storm Based Warning Size           [2266 sq km]
Probability of Detection(higher is better) [0.84]
False Alarm Ratio (lower is better)        [0.54]
Critical Success Index (higher is better)  [0.42]

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