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Snow Much Confusion

Sometimes, when you hear or read “a new record was set in Marquette today” in media reports, they are referring to the National Weather Service office in Negaunee Township. Such was the case yesterday, when it was widely reported that a daily snow record of 8.9″ was set on November 19th. Marquetters may have been scratching their heads thinking, “We maybe got 5 or 6″. I don’t see how we got 9!”

You may already be aware that the phrase “NWS Marquette” does not refer to the city proper. Sometimes, however, that phrase is omitted or put in small letters at the bottom of a graphic when discussing “Marquette’s” weather. It’s especially confusing for people who aren’t from here (students, for example) or visiting.

There’s about an 8 mile and 800ft elevation difference between the weather service forecast office just outside Negaunee and the lakeshore of Marquette. As a result, the former averages approximately 200″ of snow annually. The city of Marquette, as measured at the COOP station on Lakeshore Blvd, receives a yearly average of just under 120″. So about 40% less snow falls there than at the NWS office.

In Real Terms

To illustrate, on Nov 19-20 when the NWS office measured 12.3″, the Marquette COOP reported 6.7″ (and that’s including part of the 18th and 21st too). We’re 1 mile SW of the COOP station as the crow flies, and we recorded 6.1″ of snow for the 19th and 20th.*

So, no, we’re not under measuring. It may seem like Marquette received more than half a foot during that period, but drifts are excluded from our measurements. Boy are they impressive in places though! The gales will do that.

That said, we’ve still had one incredible November for snowfall! Officially, 14.2″ of snow had fallen by 8AM today. The normal total for the entire month is 10.9″. Unofficially, at our station next to the Vet’s Home, the 8AM total was 17.3″ with 9 days to go! We tend to measure a bit more snow at our location than they do down at the lakefront. That’s because:

  1. We are about 100′ higher which usually means more snow.
  2. We measure more often which prevents snow from sublimating (evaporating), melting or compacting.

Well, if you’re in Marquette, I hope you like a white holiday. Happy Thanksgiving to you and yours!

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UPDATE (later that day): Here’s an example headline: Marquette in Michigan’s Upper Peninsula sets daily snowfall record. While this is from downstate, I’ve seen similar things from the local media here.

UPDATE (11/22/18): Speak of the devil, here’s a link to local media spreading confusion: Monday’s snowfall breaks record for Marquette. Earth to media: we have a 147 years of public weather records in Marquette, and, oddly, they weren’t measured in Negaunee Township.

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* The NWS and this station record weather from midnight to midnight. The COOP station records from 8AM – 8AM making daily comparisons a bit difficult.

 

A Chilly November… A Chilly Year?

Yesterday, November 13th, the high was 21 (both here and at the official COOP station). The coldest high temperature on record for that day in Marquette was 20 set most recently in 1919 (tied with 1883 & 1900).

We’ve recorded 5 days in row with lows in the teens! Normal lows this time of year in the city are around 30. Normal highs are in the low 40s.  So far we are running more than 6 degrees below normal for the first 14 days of November. That follows a cold October.

If the forecast holds, it looks like there will be a slight bump in temps today, tomorrow, and Friday, although still not quite “normal”. Then we drop right back into well below normal temps for the weekend and the beginning of next week.

The Trend for 2018?

It’s been an up and down year so far, but we are all but guaranteed to end the year below normal  — barring a record setting December.* The question is by how much?

Let’s put this into the context of the past few years. In 2017 the yearly average temperature was 43.5 (when data is adjusted to match the same period of observation employed by the COOP station). That’s almost half a degree below normal.** 2016 was about 1.4 degrees above normal. We don’t have a complete data set for 2015; however, the official station reported 0.7 degrees below normal that year. Assuming our current trend of -6.1 degrees holds for November and December is completely normal, we would end 2018 about 1.7 degrees below normal. To end 2018 above normal would require November to completely erase it’s 6 degree deficit in the remaining 14 full days followed by a December that was 14+ degrees above normal!

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NOTES:

* An earlier version of this article incorrectly stated that we were likely to end 2018 well below normal for the year (-3.5 degrees potentially). After discovering an error in the supporting math, I have softened the prediction. Additionally, I have revised the calculation method to match the measurement period of the official COOP station (an observation period of 8AM – 8AM in which each month starts and ends at 8AM the last day of the month). Note that the average temperatures reported in the yearly table on our weather history page are calculated by calendar days and months. We can do that since our station is automated. Whereas the COOP station has manually observed daily temperatures once per day using a minimum-maximum thermometer (in the mornings since about 1960 and in the afternoons before that) for over 140 years!

** First we take the normal yearly average temperature over the last 30 years as measured at the Waste Water Treatment Plant, the official weather station for Marquette, which is 43.1. Then we determined the average difference between our station and the official station for every month of the year since August 2015 (listed in our weather history “normals” table under the “Depart” heading). That averages out to +0.76F. Or, put simply, 43.1 + 0.76 = 43.86 which rounds to 43.9. This preliminary number will improve over time as we collect more data. 

Weather Happenings Friday 9/21

32 Hour Roller Coaster

A decent autumn low pressure system moved in over the past 24 hours.* Pressure is heading up now, and it looks to be sunny tomorrow with normal temps (low 60s) for late September.

Autumn is typically when we start seeing big wind storms. Our max gust so far today, Friday, has been 37 mph at 11:30AM. Winds are beginning to slightly trend down as of 5PM.

Graphic courtesy of Intellicast.
Find it anytime on our Area page using the “Zone” selector at the top.

Summer Below the Bridge

Check out the big spread in temps across the state currently. It’s still in the 80s in parts of Lower Michigan!

Town should escape frost for the most part tonight, but it might be our coldest night since at least 9/9 (low of 44) if not last Spring.

As always, we archive everything we measure on the weather history page. That’s where you can find out what weather is typically like this time of year or what it’s been like in past years.

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* We hit a minimum sea-level pressure of 29.33″ (993mb) at 7AM this morning. Not a shabby number, but we’ve seen lower. 

 

The Deluge Overwhelmed Our Rain Gauge

Manual rain gauge with 11″ capacity

We’ve received 3.11″ of rain at our location just north of the Vet’s Home since midnight. That’s an all-time record for our station.

Unfortunately, our automated rain gauge had some issues overnight and missed 1 full inch of rain. Yikes! Normally, it is pretty accurate. For the last two big rainfalls (on 9/1 and 8/27) it read within a few percent of our reference gauge. I’ve now inspected the tipping bucket, cleaned it out (the cups were pretty dirty), and returned it to service. I’ll keep an eye on it.

For today (9/5), I’ve overridden the automatic gauge with the manual measurement. You’ll see the wrong value in the stats graph at the top of the stats page. The precipitation tables further down the page should be correct, though.

How big was that rain event? It looks like Marquette set a new daily rainfall record for September 5th for the 24 hours ending at 7AM this morning. The official COOP station at the Water Treatment Plant on Lakeshore Dr. reported 3.41″ during that time. The old record was 1.3″ set in 2007. By comparison, for the 24 hours ending at 8AM this morning, we measured 3.29″.

Marquette has seen even greater rainfall in its history. On September 29, 1881, 4.44″ fell!

Altogether since August 27th, we’ve recorded 7.51″ of rain! I don’t know if that’s a record stretch for the city, but it sure knocks my socks off!

We took a small amount of water into our basement. Nothing serious, though. Apparently, we aren’t alone as there are reports around town of basement flooding. Let us know in the comments if you’ve been affected by all this rain we’ve had.

Adjusted Humidity Readings

We are now adding 5% when humidity readings reach 95% since that is the maximum our sensor will read. For many years Davis Instruments’ sensors have struggled to achieve 100% humidity. Unfortunately, the problem seems to worsen with time. When we placed our sensor in service last November 28th, it would reach 98%.

Also, we are adding 1% to 92% (to make 93%) , 2% to 93% (to make 95%), and 4% to 94% to reduce the jump between 91% and 100%. Tests demonstrate these adjustments closely approximate reality.

You may occasionally see other readings besides 93%, 95%, 98%, and 100% due to 5 minute averaging of humidity values.

Raw values are available on the stats page.

Here’s some more info on this problem if you’re interested:

We have a backup weather station for emergencies. It also contains a Davis VP2 station with an SHT31 sensor that is less than 2 years old. It maxes out at 96% humidity, but it also has an average +8% bias below 80% during the warm season (May – Sept). So it has a wet bias in the middle range in addition to a dry bias in the top range. Keep in mind that the maximum error for this sensor is supposed to be 3.5% according to the manufacturer.

We are not the only ones to experience these issues. Many other Davis VP2 weather station owners have reported them (in a thread approaching 1200 posts). Davis says they are “looking into it”, although that was almost 2 months ago now. Some particularly brave souls have attempted to informally wire up older (SHT11/SHT15) and/or unsupported sensors (SHT75) with varying degrees of luck. We’re not keen on performing ad hoc experiments with our primary temperature/humidity sensor. Some combination of Murphy’s Law and common sense would argue that such slapdash “solutions” will inevitably break at the worst time. Indeed our various attempts with other sensors on the test bench have not gone well. Therefore, we await a viable, proven fix preferably from Davis Instruments.

[UPDATE 9/21/18: Most of those enterprising individuals referenced above are now indicating an array of problems with the SHT75 sensor ranging from sudden failure to gross errors. It’s uncertain whether the fault lies with the sensor or the implementation. Either way, at present there appears to be no good workaround to the issues mentioned above with the SHT31.]

[UPDATE 10/23/18]: We recently swapped out our SHT31 sensor suite as part of a preventative maintenance routine. The new humidity sensor arrived with a +6% average (wet) bias below 55F, an average +4% bias above 55F and a maximum reading of 98% (after several hours in saturated air). We have corrected these deficiencies with custom programming.

When Weather Apps Fail at Weather

I wrote about this yesterday on Twitter. Given the limitations of that platform, however, I couldn’t really go deep. Let’s dive in.

Here are two screenshots taken within 60 seconds yesterday afternoon:

 

The 1st image is of a popular weather app recently redesigned for the iPhone. The 2nd image is our universal web app loaded in Safari on an iPhone.*

Continue reading “When Weather Apps Fail at Weather”

Noticed Some Changes Lately?

Last week I tweaked the color scheme to match the forecast icons. We’re keeping with the sky/water/sand theme only now just a bit brighter and more coherent.

Today, I removed the weather history icons that lived beneath the current conditions. Nobody was clicking on them. The images accounted for about 1/3rd of the data necessary to load the home page. That wasn’t a good tradeoff between useful information and bandwidth consumption. I’m always mindful that people have limited data on their mobile plans. Speed is another concern too.

I also moved the dropdown selector that was in the conditions section to the page settings (gear wheel icon in the upper right of home page). That’s where it belongs rather than cluttering up the current conditions. If you need to change the frequency of updates, it’s just one click to get there. Again, the data shows that few people adjust that setting, so why not put it where power users naturally go anyway?

One more tiny detail. I added the time zone to the conditions and forecast update times. When visitors travel, they shouldn’t have to wonder if the times listed are local time or Marquette time. The forecast will always be updated in Eastern time. The conditions will be updated according to the current time zone selected on your computer or mobile device. In Marquette, they should both show “EST” or “EDT” depending on Daylight Saving Time.

Also, I should mention that we recently changed hosts about 3 weeks ago. Regular, long-time visitors may remember some extended outages lasting hours, even days in one instance last year due to some lackluster planning by our old host, A2hosting. I picked out another Michigan hosting company, Liquid Web.  Not only do they own their data center in Lansing (rare), but their operation is prepared to withstand power & internet failures, weather events, and DDOS attacks (coordinated hacking) among other unfortunate events. That’s not to say the site will never go offline, but, hopefully, not as frequently or for as long. It’s much more expensive to host with them, but their speed and reliability so far have been phenomenal.

Well, thanks for visiting. If you enjoy the site, please tell your friends & family!

Demolish Marquette to Improve Forecasts?

Would forecasts improve if we removed all the buildings, ripped out all the concrete and moved everyone to tents situated along Lakeshore Blvd? Short answer: likely.

Too often the forecasted high temperatures for Marquette run well below the measured high temperatures, especially on sunny days when the wind isn’t blowing off the lake. This is true of all forecast agencies I’ve observed to one degree or another. It just so happens the local National Weather Service, our forecast provider, is also guilty of this trend. Continue reading “Demolish Marquette to Improve Forecasts?”

What Happened To The Forecast?

The website’s featured forecast provider, Weather Underground (WU), announced a change in policy last month. They were no longer going to allow free, limited access to their raw forecast data (API). Instead, they would begin charging hundreds per month even to those who contribute data like we do. Since this site generates no revenue, the new price tag is a nonstarter.

I’ve been exploring alternatives in hopes of continuing to offer dual forecasts. None of them have met my requirements of accuracy and affordability. Therefore, I’ve decided the National Weather Service (NWS) will be the sole forecast provider for marquetteweather.com.

In addition, the hourly forecast will not be replaced due to problems inherent in the forecasting process. Presently, the software-based weather models do not adequately represent the transient effects of the Great Lakes frequently leading to significant errors exceeding our forecast target of +/- 3 degrees. Plus, the forecasts don’t update often enough to keep pace with our weather. Routine changes in wind direction, cloud cover or precipitation can transform conditions in a matter of minutes — as most Marquetters intuitively understand.  Continue reading “What Happened To The Forecast?”

A New Stats Page is Born!

Synopsis: we are archiving the city’s climate and presenting it to the community in what we believe is an accessible and easy-to-read format.

Perhaps you’ve visited the Statistics page previously. WeatherCat, the software that grabs data from the weather station, automatically generated those numbers and even uploaded them to the website.

Well, the old saying “if it’s easy, it ain’t worth doing” proved true, unfortunately. As time went on, I kept spotting more mathematical errors. Plus, the tables were not very readable. Visitors couldn’t access daily history after 60 days. Navigating the page was difficult too.

Over a month ago I began overhauling the page. This involved taking raw data directly from the database and programming  complex mathematical formulas. Smoke may have occasionally emanated from the computer (not to mention my ears!). Continue reading “A New Stats Page is Born!”