Radar Offline Until July 24th

Beginning Monday July 13th the radar will be down for maintenance until sometime on or around Friday July 24th. Technicians will be swapping out the pedestal underneath the radome (giant soccer ball) you see near the old County Airport location on US-41 in Negaunee Township. See this NWS blog article for more information.

Radar Maintenance Until 3 PM 7/1

The radar is down until approximately 3 PM on Wednesday July 1st for maintenance.

Be aware that starting Monday July 13th the radar will be down for approximately 2 weeks. Technicians will be swapping out the pedestal. See the NWS blog article for more information.

Here Comes The Sun

You might have noticed a couple new readings in the “Current Conditions” section of our home page. I’ve installed 2 new sensors on our main weather station, a Davis Vantage Pro2, to measure output from the Sun.

One sensor reads a narrow band of ultraviolet (UV) radiation. The 290 – 390 nm spectrum of the sun’s shortwave energy particularly affects human health. Readings are translated into a universal UV index (1 – 16 scale).

The other sensor measures broad spectrum solar radiation (a.k.a. “solar irradiance”, “solar insolation”) between 300 – 1100 nm. It’s output scale is 0 – 1800 Watts per meter squared (W/m2). This is useful for solar energy management & approximating cloud cover / ambient light. You may wonder “can’t I just look out a window?” If you are in Marquette, yes. If you are elsewhere, no.

Continue reading “Here Comes The Sun”

Instrument Calibrations

As noted in the about page, I regularly check our sensors to be sure they are within specifications. Over the last couple weeks I have been conducting tests.

Temperature was right on. That’s typical, as our sensor is pretty bulletproof. I have a platinum RTD digital thermometer that’s accurate to within 0.1° F (best to check on a cloudy, windy night to eliminate radiation as a factor). I also have a laboratory-grade aspirated psychrometer with a dry bulb thermometer that’s extremely accurate. It’s analog, so the biggest challenge is reading between the lines. But my tests show the station’s thermal sensor is within 0.5° during the day which is quite good. There’s also a backup sensor on site as well. At night or on cloudy/rainy days, the two sensors are normally within 0.2° F. During sunny days, height (7 ft vs 21 ft) and shielding differences (active vs passive ventilation) can frequently lead to 1° differences in either direction. 2-3° differences are not out of the question when it’s particularly calm and sunny.

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Recent Site Changes

Earlier this week I removed the cloud icons that formed the main navigation links throughout the site. This design methodology had passed its shelf life. It also limited the font size of the embedded text. By deploying more generic buttons I was able to change its font type & size. This should make navigation clearer & easier to use.

In the weather history section, you can now click on each of the 24 hour graphs at the top for a much larger, more detailed version of the image. These images are not straight duplicates of the data in the smaller graphs and contain some custom “enhancements”. For instance, the detailed dew point and humidity graphs contain corrected & smoothed values (rolling 5 minute averages to prevent readings from jumping around too much when the air is unstable). The software that connects the weather station to the website cannot correct for sensor errors in real time. I do that immediately after the reading is taken. Then I send the corrected values to the site (current conditions, history tables). Unfortunately the smaller graphs are generated before I can access them. Note that the larger dew point and humidity graphs are still “initializing” which means that some of the data from yesterday is missing. This will correct itself by about 8 PM Saturday evening.

I also fixed a small bug whereby if you had selected metric units in the page settings of the City page (home page) AND you also selected unrounded temperatures you would only see rounded temperatures.