IEM Daily Bulletin for Jul 21 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 21 July 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Jul 20 11:30 AM	iem,main	⚡️ Pre-emptively wait longer for HRRR HR%6 RT Jobs	Link
Jul 20 12:47 PM	iem,main	🎨 Update ISUSM 4in soil QC algorithms	Link

Daily Feature

Hours of Smoke
Date: 20 Jul 05:30 AM
Votes: Good: 20   Bad: 0 Abstain: 0

Up until Sunday, Iowa had mostly avoided the smoke plumes originating from the wild fires over northern Minnesota and Ontario, Canada. Unfortunately, the smoke arrived over eastern Iowa on Sunday. The featured map presents an accounting of the number of hours since 6 July that a plotted airport weather station has reported smoke within its METAR observation report. Smoke is encoded as "FU" within a METAR and that code originates from the French word Fumée, for those of you that are curious. The map shows the largest total number of hours stretching from northern Michigan to the east coast.

NWS Watch/Warning Summary for 12 AM 20 Jul 2026 - 12 AM 21 Jul 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	23	3	1	1	3	0	0	2
Svr Tstorm	150	38	2	7	27	0	0	2
Flash Flood	58	5	0	2	3	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: 172 Verified:  59 [34.3%]
Polygon Size Versus County Size            [14.2%]
Average Perimeter Ratio                    [23.2%]
Percentage of Warned Area Verified (15km)  [18.7%]
Average Storm Based Warning Size           [1356 sq km]
Probability of Detection(higher is better) [0.81]
False Alarm Ratio (lower is better)        [0.66]
Critical Success Index (higher is better)  [0.32]

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