City WeatherOn Labor Day (9/4/23) our station recorded a maximum temperature of 95.7° which eclipsed our previous all-time high of 95.2° on June 6, 2021. We have been (unofficially) recording weather at this location since July 2015.
Our maximum heat index on Monday 9/4 was 102°. The dewpoint topped out at 72°. It was a very muggy day by Upper Michigan standards (dewpoints typically in the 40s/50s in early September).
Last night around 9 PM EDT, we experienced a deluge of rain during a severe thunderstorm. Our automatic tipping spoon recorded the second highest rain rate in the 8 years we’ve been online (10.7″/hr). Overall, we picked up just over 1.5″ of rain in half an hour with about 1″ falling in the first 15 minutes of the storm.
We clocked a 37 mph wind gust during the storm. However, each wind measurement must last up to 2.5 seconds to be recorded by our system. It’s quite possible higher, shorter-lived winds were present during that storm as radar had indicated up to 60 mph gusts according to the severe thunderstorm alert issued by the National Weather Service.
There was lightning aplenty but no hail. We got quite the hail storm on Saturday July 22nd. The entire property was coated with pea size pellets.
Marquette is running WELL above normal for July rainfall. So far 4.89″ has been recorded by our automatic gauge (which is checked against a manual gauge daily). Marquette’s 30-year normal rainfall for July is 2.77″.
Incidentally, the third highest rain rate in our history (9.75″/hr) was recorded less than two weeks ago on July 15th when we picked up 0.64″ for the day.
Just a note…
If you are curious why we experienced an AQI (Air Quality Index) over 400 during the lunch hour it’s because my neighbor was burning trash. Otherwise, the air quality has been good to moderate today.
Researchers sometimes come to the site and examine the Weather History for a given day — sometimes years afterward — and might furrow their brow at such an extreme outlier not recorded by any other nearby station. Hopefully they find this blog post.
Previously, if you wished to navigate the website in a mobile device you needed to go (back) up to the top left navigation menu. As of today, if you have scrolled to the bottom of the page, you can simply access the navigation in the footer. This has always been the case for those using PCs & Macs.
I had struggled to preserve the navigation in smaller viewports without it appearing cramped in that space… until now. I will leave the “Back to Top” links in place for those who want a quick way to start over from the top of the page.
Also I have added a light blue background color to distinguish this section from surrounding content. In night mode, the footer will turn to a deep navy.
As always, the site is completely responsive which means you can view it on any modern device with the screen size/orientation of your choice. You can even put it in a small browser window when using a computer alongside your other app(s). Home page conditions will update every minute by default and the entire page will refresh every 10 minutes.
I invite you to make full use of the site. Each page is a collection of freely-available, unique resources not found in one space elsewhere.
As it stands we have decent site engagement. That said, plenty of folks — even longtime regular users — have never left the home page. I assure you, we don’t put filler pages on the site. It’s all useful!
We’ve noticed for awhile that the top value for humidity readings seems to be in the low to mid 90 percentiles (in unadjusted raw values). The humidity sensor’s effective ceiling has dropped since we last performed a significant top-end adjustment in 2020.
Perhaps you’re thinking, “why not just replace the sensor?” Because a new sensor, while perfectly affordable and somewhat more accurate in very moist air, has other more unpredictable errors which will not be easily correctable. I base this assertion upon years of experience with the SHT31 sensors, particularly when exposed to fan-assisted air movement (~2.25 m/s). A replacement sensor need to “harden” in the field for years before being deployed. We’ve had one “baking” in our backup station since last fall, and it’s not ready yet. It’s only to be used in the event of a failure of the primary station.
In the early morning hours of Monday July 24th our location experienced significant dewfall. Dew coated all objects within view, including the housing of our weather station. Unfortunately, our station’s max humidity reading that morning was 91%. Not good. A fan-aspirated weather station, such as ours, will sometimes run a bit drier than nearby air-ventilated stations which are susceptible to moisture depositing within their housing & on sensors when winds are low but air is not quite saturated (95-100% RH). But given the level of moisture observed combined with empty radar images & precipitation gauges, our sensor should have read upper 90 percentiles at least, with or without a fan to move air through the housing. Other nearby weather stations were reporting maximum humidities for hours, including our backup station.
After hunting through humidity records this past year and observing patterns, I have tweaked the “dry bias” algorithm that progressively adjusts readings above 85% relative humidity. It’s a bit tricky because the sensor also has a “wet bias” that stretches into the low 80 percentiles. Certain values have to be transitioned to make the handoff at 85 smooth yet accurate. Luckily, I’ve got lots of data available from past and present checks against our reference psychrometer (accurate to +/- 1% RH) to aid in the process.
You should now clearly notice when fog, dew or significant precipitation events occur just by examining humidity tables on our weather history page. Future maximum values should be close to, if not precisely, 100%.
Questions? Thoughts? Hit the comment form below.
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UPDATE 7/27/23 2:55 PM: Fog descended on Marquette last night! It lasted for several hours. A decent rain storm followed this morning which re-saturated the air with moisture (nearby stations all at max humidity). The new algorithm couldn’t have performed better!!
(Auto night: 10:48 PM - 5:04 AM)