IEM Daily Bulletin for Oct 18 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 18 October 2025

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Oct 17 9:08 AM	iem,main	🐛 Correct to use 1991-2020 climo	Link

Daily Feature

Jul vs Oct Highs
Date: 17 Oct 05:30 AM
Votes: Good: 11   Bad: 0 Abstain: 0

Temperatures warmed nicely again on Thursday with about half of the state reaching 80+°F for high temperatures. Sometimes it is difficult to contextualize how anomalously warm a temperature is during a month that should feel more like fall than summer. So the featured chart makes an attempt at this by comparing daily high temperatures during July and October for Ames. The left panel is a q-q (quantile) plot which matches temperatures by their observed frequencies. So a 80°F high temperature during October is comparable in occurrence frequency to a high of 95°F during July. The right hand plot presents histograms of each month's temperature distribution. There is a surprising amount of overlap between the two, but obviously October has most of its distribution below the July minimum value. The right hand table lists out the percentile values for each month and the difference between the two.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 17 Oct 2025 - 12 AM 18 Oct 2025 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	0	0	0	0	0	0	0	0
Svr Tstorm	0	0	0	0	0	0	0	0
Flash Flood	0	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

No SVR+TOR Warnings Issued.