IEM Daily Bulletin for Aug 20 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 20 August 2025

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Aug 19 8:09 AM	iemone,main	🐛 Address N0Q to N0R archive switch	Link
Aug 19 8:11 AM	iemone,main	🐛 Address time input UI bugs	Link
Aug 19 8:27 AM	iemone,main	💚 Relax test	Link

Daily Feature

Upper Right Quadrant
Date: 19 Aug 05:30 AM
Votes: Good: 8   Bad: 1 Abstain: 0

Even with some morning thunderstorms, the afternoon turned out steamy again on Monday with dew point temperatures well into the 70s. Such has been the case for much of this summer with warm and wet conditions dominating. The featured chart attempts to illustrate this by plotting a time series of 14 day standardized departures of average temperature and precipitation for Ames evaluated every seven days since about the beginning of May. The departures are expressed in sigma units to removal some of the seasonal variability. As the feature title states, we have spent most of the summer within the upper right quadrant (above average precipitation and temperature departures) on this chart. Remarkably even touching a three sigma precipitation departure twice. The good news for those sick of this weather pattern is that cooler and drier conditions are in the forecast after another sticky day on Tuesday.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 19 Aug 2025 - 12 AM 20 Aug 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	90	0	0	0	0	0	0	0
Flash Flood	15	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:  89 Verified:  25 [28.1%]
Polygon Size Versus County Size            [23.5%]
Average Perimeter Ratio                    [24.0%]
Percentage of Warned Area Verified (15km)  [16.2%]
Average Storm Based Warning Size           [1093 sq km]
Probability of Detection(higher is better) [0.42]
False Alarm Ratio (lower is better)        [0.72]
Critical Success Index (higher is better)  [0.20]