IEM Daily Bulletin for Jul 16 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 16 July 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Jul 15 9:30 AM	iem-database,main	✨ Add field rectangle generalization storage refs dailyerosion/dep#435	Link

Daily Feature

Record High Heights
Date: 15 Jul 05:30 AM
Votes: Good: 11   Bad: 0 Abstain: 1

A surface high pressure system and associated upper level ridge have been in firm control over Iowa's weather these past few days with hardly a cloud in the sky. Unfortunately, very hot and dry air have lead to numerous wildfires over northern Minnesota and into Canada. This "heat dome" system, as it is sometimes colloquially called, has been impressively strong. During the warm season, one measure of its strength can be found by the maximum height of the 500 hPa pressure surface. Due to the ideal gas law, a very warm lower atmosphere will vertically "push" the height of a pressure surface further away from the ground. Meteorologists like to consider a height of 6 kilometers has an impressive height for the 500 hPa pressure to be found. And that finally brings us to the subject of today's featured chart. The chart presents the 2026 observed heights and period of record ranges of the 500 hPa surface as recorded from the Minneapolis sounding. The monthly max and min values are labelled. The sounding from Monday evening (00 UTC 14 July) came in at 6,010 meters, which according to unofficial IEM archives is the highest height on record for the site. Typically, these very strong "heat domes" happen further south and particularly southwest with 6km heights happening a few times per year.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 15 Jul 2026 - 12 AM 16 Jul 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	8	0	0	0	0	0	0	0
Svr Tstorm	53	0	0	0	0	0	0	1
Flash Flood	49	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:  61 Verified:  26 [42.6%]
Polygon Size Versus County Size            [10.1%]
Average Perimeter Ratio                    [18.2%]
Percentage of Warned Area Verified (15km)  [25.3%]
Average Storm Based Warning Size           [995 sq km]
Probability of Detection(higher is better) [0.85]
False Alarm Ratio (lower is better)        [0.57]
Critical Success Index (higher is better)  [0.40]

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