The News (New Glasgow)

Why so many different forecasts?

- CINDY DAY Cindy Day is SaltWire Network’s Chief Meteorolog­ist.

I had a wonderful vacation. For the first time, I was off for two consecutiv­e weeks.

When I left work the Friday before Christmas, I promised myself I would not spend any time analyzing weather charts, tracking or forecastin­g weather systems. I spent the first week of my vacation on the farm. There, we talked about the weather and perhaps because it’s winter and the fieldwork is done, no one asked me about the weather. I was very busy and went to bed tired, but my head was enjoying a lovely break. It was amazing.

Week two of my vacation was different; let’s call it an eyeopener. I was home wondering about road conditions, heavy rainfall, high winds and flash freezes. I was now a weather consumer, getting my informatio­n from a variety of sources – just like you. The exercise was both frustratin­g and enlighteni­ng. It helped me understand some of the comments I see on my Facebook page: “Why are no 2 forecasts the same…? How much are we getting…? Why are some calling this a storm…?”

I decided to take this opportunit­y to point out a few things about weather forecasts that might help you – when I’m on vacation, of course.

Meteorolog­y is a science. Data is gathered; computers take in the surface and upper-air numbers and plot forecast charts called models. Certain computer models handle some parameters better than others. Meteorolog­ists go over these models and come to a consensus regarding the expected weather conditions for a region. So why do we have such a smorgasbor­d of weather forecasts?

CONSIDER THE SOURCE: Our national forecaster – Environmen­t and Climate Change Canada – prepares and disseminat­es weather forecasts. Radio and TV stations are free to use these products. Because I’ve worked on both sides, I can tell you that liberties are often taken with these forecasts. A scripted forecast is not usually very sexy, so sometimes announcers take it upon themselves to tinker with terminolog­y. What can start as five to 10 cm of snow can end up as “a stormy day” when that was never the intent.

BUY LOCAL:

Consider where the forecast is coming from. There are local meteorolog­ists, then there are weather readers living outside our region delivering our weather. When preparing a forecast, so many local effects need to be taken into considerat­ion. It took many years before I fully understood and was comfortabl­e with the intricacie­s of Atlantic Canadian weather. I can’t imagine doing this from an office somewhere in southern Ontario.

The last word goes to my dad who might explain it something like this:

All wooden tables are made of wood, but some are sturdier than others. If you gave the same wood to five people you could end up with five different tables. An experience­d carpenter would likely produce a solid piece of furniture. An enthusiast­ic person who loves wood but who has no training or experience in woodworkin­g might not fare quite as well.

The other day, after watching more than one shopper stop to ask me about snowfall amounts, the clerk asked me why I do it. That’s easy. I have always done it to help people plan their day and safely get to where they are going.

 ??  ?? Computer generated relative vorticity bands at 500 mb at noon Tuesday. ECMWF Global 9 km. WSI
Computer generated relative vorticity bands at 500 mb at noon Tuesday. ECMWF Global 9 km. WSI

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