# National Weather Service radar shows mayfly swarm in Chicago **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 24, 2013, 9:57pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425 "2013-07-24T21:57:07Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [July 24, 2013, 9:57pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/1 "2013-07-24T21:57:07Z")
[http://www.crh.noaa.gov/news/display\_cmsstory.php?wfo=lot&storyid=96161&source=0](http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=lot&storyid=96161&source=0) > [@](#): > > It is believed that a lake breeze carried these mayflies inland on Saturday evening. Looking at the radar loop from Saturday evening we can see a pronounced lake breeze boundary oriented from northwest to southeast across the western suburbs. Near the end of the loop the boundary begins to dissipate. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [July 25, 2013, 12:42pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/2 "2013-07-25T12:42:44Z")
There are still a few bugs in the system. ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [July 25, 2013, 11:28pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/3 "2013-07-25T23:28:16Z")
I, for one, welcome our new Mayfly Overlords. Well, hell, you knew someone was going to say it. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 25, 2013, 11:34pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/4 "2013-07-25T23:34:58Z")
I’m about 300 miles north of the Chicago area. Perhaps I’ll see the mayfly swarm in a few days. We typically have about 2 days of mayflies each year, if any; they blanket the screens and windows, then it’s over. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [July 26, 2013, 10:39am UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/5 "2013-07-26T10:39:01Z")
Here in the Mississippi River Valley we get several hatches that are big enough to show up on radar: [http://www.crh.noaa.gov/arx/?n=mayflygeneral](http://www.crh.noaa.gov/arx/?n=mayflygeneral) Brian ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [July 26, 2013, 3:00pm UTC](https://boards.straightdope.com/t/national-weather-service-radar-shows-mayfly-swarm-in-chicago/664425/6 "2013-07-26T15:00:42Z")
bird and insect events can be fairly regular. there are lakes, marshes and other water features where insects will hatch as a group. waterfowl bird migrations will also happen as a group. these might span a few days and be regular within a couple weeks time window every year. bats will also produce daily radar events. subtracting these events from raw radar is done after enough history.