Friday, February 15, 2013

Why We Can't Forecast Next Week's Storm... Yet

People have been asking about this POTENTIAL winter storm next Thursday and Friday. I put POTENTIAL in all caps because we don't know how bad it's going to be... not yet, at least. That's because time is the biggest enemy of weather forecasters everywhere.

Let me explain. Our forecast models work by taking current weather conditions and applying them to complicated mathematical equations. This eventually gives us the computer's forecast. The thing to remember is each day of the forecast is dependent on the day before it. In this example, we have rain on Thursday and snow on Friday.

Since each day's forecast depends on the day before it, any change in the forecast can compound on itself over time, meaning small changes turn into bigger ones over the course of several days or a week. In this example, we made Monday warmer. That, in turn, can make the computer warm temps up over the long haul... meaning rain on Friday instead of snow.

My basic point here is not to panic just because a particular model run is calling for a bunch of snow a week out. That's because subtle changes in the forecast over the coming days can change what we actually see in a week's time. We'll have a much better idea of what this storm could do by the beginning of next week... SO DON'T PANIC! Not yet, at least. -BA

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