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Our Wind Cups Froze

Like every other object in its path, Monday’s ice storm did a number on our anemometer (wind gauge). The pole to which it’s mounted cannot be retracted because… you guessed it. So nothing can be done but wait.

It’s going to take either a big gust of wind (> 25mph), some sunshine and/or warmer temperatures to free the spinning cups. Until then, wind speeds will read 0. With temps barely cracking 20 in the next 5 days, it might be awhile before it’s fixed.

[UPDATE 2/5/19 6PM]: High winds forecast for Thursday may provide sufficient energy to loosen the ice. Fingers crossed.

The directional indicator is currently turning as it should.  So if you see “N”, that means winds are coming from the north.

Just FYI, the National Weather Service says this is only the 2nd time in the 2000s that an Ice Storm Warning has been issued. It’s just not something we are accustomed to up here. That’s doubly true for February. We got about an inch of freezing rain out of that storm!

If It’s Below Freezing, Why Is It Raining?

Long story short… freezing rain occurs when the atmosphere is warmer higher up than at ground level. It’s called an inversion. Usually it’s a shallow layer of warm air fairly close to the ground (below about 5000 ft) that precipitation falls through and melts. There is insufficient time for it to reform into snow before hitting the ground. Since the ground is frozen and the temperature is below 32 degrees, it will freeze.

We expect the lower atmosphere to continue cooling this afternoon so if any additional precip develops, it should fall as sleet or snow. Knock on wood.

January WAS Running Warm…

That was until the #PolarVortex hit us last week. No chance of that now. After ending 2018 below normal, we are off to a cool start for 2019.

Snow is running below normal too. That makes sense when its colder as the atmosphere runs drier.

The latest winter storm has underperformed (thus far) in terms of city snowfall. No measurable snow as of 10:30PM Tuesday night. Too much westerly flow, not enough northerly.  That hasn’t kept the wind from kicking up quite a bit of blowing snow. Wind chills as of this posting were -20 and falling. You never know. I could post this, go to bed, and wake up to 6″ tomorrow.

This weekend should offer a reprieve, but don’t get too used to it. There appears to be another cooling trend in the extended outlook.

Punxsutawney Phil might be held at gunpoint this year.

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[UPDATE Wed 1/30/19 9:00AM]: Our snow board had only a trace of snow on it this morning. Our gauge caught what amounts to something like 1″ of snow (when you reconstruct it from liquid equivalence and compensate for under catch from wind).

Subzero Sunday

Not since February 2015, has Marquette seen a high temperature (measured from 8AM – 8AM) below 0 degrees. Can we add another subzero day to the record books?

The Coast Guard station is only about 100 yards from the official station in Marquette. It reported a high of -2 yesterday. At our station half a block from the Vet’s Home, we reached a daytime high of -2.5.

Also we’re keeping an eye on whether a record cold high temp was achieved. The previous record of -3 was last set in 2014. Meanwhile, we await official word. I will post an update below once I know.

Another day spent below 0 is possible on Wednesday. We should escape the worst of it, though, as the main core of cold air slides south of us. Be careful if you are traveling south into MN, WI, IL or lower MI. Life-threatening cold is in store.

Relief looks to arrive this weekend. 30s maybe. Keep an eye on the extended forecast.

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UPDATE 1/28/19 1:00PM: We’ve received the report. The official weather station in Marquette saw a high of 1 degree between 8AM Sunday and 8AM Monday. Therefore, no records or notable events.

Between 4 & 5AM this morning, there was a rise in temp. We hit -1. The Coast Guard reported 0. Guessing the official station rose to +1 around then.

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”