Wednesday, March 28, 2007

If the forecast is wrong, how can the predictions about global warming be right?

Patrick from Dixon writes: "if they (Meteorologists) can be wrong about weather conditions in a 24 hour period in the immediate area in spite of having radar of approaching conditions, why should we believe that long range forecasts about global warming in 10, 20 or 100 years are accurate?"

You’ve brought up some very thought provoking things! First of all, the NWS uses POPs (or probabilities of precipitation) in their forecasts. Using a percentage chance of rain is thought to help the public’s discernment of the forecast. We all know that a 30% chance of rain means that our outdoor plans will probably go off without a hitch. However, a 70% chance of rain still leaves a 30% chance that rain won’t happen.

WREX-TV doesn’t use POPs. We feel that they are somewhat confusing. We use words like slight chance, scattered, and likely to convey the likelihood of precipitation. Hopefully, it is a little easier to understand.

As far as your comments about Global Warming, I must remind you that weather and climate are two very different things. Meteorologists forecast the weather. Climatologists forecast the climate. A lot of what we use (as Meteorologists) revolves around weather observations and operational weather modeling. We use these things to put together a written forecast which we then put on the air each morning and night. Forecasting the weather is very different than forecasting climate. The folks at the NWS are forecasting the weather and are not the same group of people that are forecasting climate change.

Climate is the observed weather over a certain span of time, usually a long period of time. Climatologists look back over years of data then show the changes that have been made. They have observed that the climate is warming (not only across our nation, but the world as a whole). Because the specific reasons for this climate change can only be speculated at this time, the debate has ensued. Whether or not this climate change is man-made remains to be seen, but the pro-global warming brigade believes pollution should be curtailed so the change isn’t so drastic.

Many people say to me “If global warming is occurring, why aren’t we breaking record highs all of the time?” The reason we aren’t breaking records all of the time is because we have to look at the difference between daily weather and long-term climate. For instance, we had an exceptionally cold February this year. However, the cooling of February was cancelled out because of the warmth January and March have brought...so our climate is still warmer this year compared to climatic averages.

I wish I had an answer to the global warming debate but I think the more people like you ask questions and do their own independent thinking, the better off we will all be.

As far as the accuracy of the NWS forecasts (and our own), keep in mind that our accuracy would be very high if we were forecasting for one particular point on the map. Both the NWS and WREX-TV forecast for an entire region...pinpointing when it will rain in Dixon versus DeKalb is a daunting task sometimes!

Thanks for your question Patrick!

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