(From the January, 2014 issue of “Allen County HamNews.”)
We often focus on thunderstorms and related weather when we consider the role of SKYWARN spotters. But reports of winter weather from trained spotters are also important to the National Weather Service. For that reason, NWS has made available via the Web a 23-minute instructional video, “Measuring Snow.” It turns out that making accurate reports of winter precipitation is more involved than you might think.
Not every part of your back yard is appropriate for snow measurements, so the video begins with a discussion of how to decide where to place equipment, including a snow board. For example, the video explains why your deck or patio is not the best place to measure snow.
The video explains how to capture snow in a rain gauge and a good way to melt the captured snow so you can report a water equivalent (the NWS considers this to be among the most important information you can report).
The video also discusses the measurement of new snowfall and total depth and explains why measurements taken on grassy surfaces are usually inaccurate.
The largest enemy of accurate snow measurements is wind. In high-wind conditions, gauges often catch less than the total amount of snow that fell. For such cases, the video explains how to take a core sample to get a more accurate reading of precipitation.
These are just a few of the issues the video covers. If you’d like to help the National Weather Service this winter by providing accurate winter precipitation measurements, I strongly encourage you to view the video before you make a report. You can find it at http://tinyurl.com/md3yd9n.
By the way, have you ever wondered how NWS decides whether to issue a Winter Storm Warning? The official criteria is, “Combination of any winter warning hazards, including significant blowing and drifting snow below blizzard conditions (lesser amounts may be warranted especially if significant mixed precipitation in an early or late season event).” You can read the criteria for all winter weather products (including advisories, watches and warnings) here: http://tinyurl.com/n3dox2j.
Do NOAA Weather Radios (NWR) sound off when NWS issues a Winter Storm Warning? It depends. The official list of products that warrant NWR alerts is available online here: http://tinyurl.com/kffp9bl. You’ll note that many products, including Winter Storm Warnings, prompt NWR alerts “at forecaster discretion or in response to customer demand” (including the requirements of emergency managers and broadcasters as outlined in local and state Emergency Alert System plans).
Finally, by the time you read this, annual SKYWARN spotter training sessions will be less than two months away. This is therefore a great time to complete the free online spotter training course provided by The COMET Program. Or, if you’ve already completed the online training, it’s a good time to review the modules. That way, you’ll have all the background you need for the upcoming group training sessions. You can find the modules here: http://tinyurl.com/3z5l4lb.