Blog

Rethinking Snow Measurements

Earlier I announced the end of snow measurements. Well, after thinking it over some more, I decided on a compromise solution. I will continue measuring snow but only as time, weather, and health permits. This may or may not happen at 8 AM each morning. I may skip days entirely. Or I may just put in an estimate if the wind has wreaked havoc on the measurement area. After all, these are unofficial numbers intended to give an example of what’s happening in the city.

I’ve created a new Snow Measurements page which will list any and all measurements throughout the season (October 1 – May 31).

Hope everyone enjoys the info!

No More Snow Measurements

Unfortunately, I have decided to discontinue snow measurements. Last winter finally persuaded me of the limits of collecting and tabulating daily snowfall — even on a double city lot. The wind eddies around nearby structures result in huge drifts when winds gust upwards of 40 mph. As Marquetters know, this is an all too common event in the winter, particularly when storms come off Lake Superior. It then becomes very difficult or even impossible to separate drifted from newly fallen snow. Sometimes the snow boards are simply blown clean. Taking measurements from multiple locations won’t improve matters when everywhere around is subject to the same forces.

Continue reading “No More Snow Measurements”

Radar Down from 9/9 – 9/13

The National Weather Service Marquette will be replacing some radar equipment starting Monday September 9th through Friday September 13th. During that time, you will see a “Down for Maintenance” indicator where the radar image typically resides on our home page.

For more info, see their blog article: https://www.weather.gov/mqt/KMQT_SLEP

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UPDATE 9/11/19: Apparently the NWS radar techs wrapped up their work 2 days early. The radar was returned to service this afternoon.

Radar Down Until Thursday 8/8

According to the local National Weather Service office, the radar will be down for preventative maintenance until Thursday August 8th at 3:00 PM EDT.

If a storm develops, the radar should be temporarily re-enabled.

All radar options on our site will be affected by the outage.

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UPDATE 8/6/19 2:00 PM EDT: Radar is back online. No storms expected today. Not sure what’s going on. No update from NWS.

Humidity Adjustments

It appears our humidity sensor’s maximum value has lowered over time. This is, unfortunately, common with our particular weather station’s sensor. The process is accelerated by 24 hour fan aspiration. We’ve seen this behavior in 3 other units we’ve deployed in the past.

When we first installed this sensor last July, the top possible humidity reading was 98%. The ceiling has since lowered to 96%.

After a round of tests using an independently calibrated device yesterday & today, and in an effort to stay within +/- 3% of true ambient humidity, we’ve programmed adjustments to the following humidity readings:

  1. 94% +2% = 96%
  2. 95% +3% = 98%
  3. 96% + 4% = 100%

Because we use a 5 minute rolling average for humidity at times you will see values between 96%, 98%, and 100%.

The good news is, based on experience with this sensor model, the biases should now be fairly solidified and predictable.

The bad news is that when humidity starts to descend from persistently moist conditions (>95% and >2 hours) the sensor can lag because of moisture uptake within the protective housing. Our programmed offsets exaggerate this process. We believe it’s more important to properly indicate the arrival of fog & dew than the drier air that immediately follows.

As always, though, we will test to verify sensor performance every so often and adjust accordingly.

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NOTE: We send corrected humidities to CWOP & Weather Underground.

UPDATE 5/28/19: After an overnight period of saturated air, discovered the sensor’s ceiling is actually 96%; corrected offsets.