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Expert: - 8/20/2011


Question
I was wondering how accurate a 7-14 day weather forecast is? I will be going away on a camping trip from August 28 to September 2, from what I can see the weather is going to be fairly cool. The week prior is showing very hot weather. I will be in Parry Sound, Ontario. How are these predictions calculated? Thank you for taking the time to answer my questions.

Answer
Laura,

In general, the farther out into the future you go, the less accurate a forecast becomes. A forecast for one hour from now is extremely accurate! A forecast for two weeks from today has very little chance of being close to reality. We can usually hit the overall trends beyond a week or so, but we cannot get the specifics of the forecast. In other words, we usually have a decent idea that temperatures will either be above or below normal, and whether it will be an average, drier, or wetter than normal pattern. However, we can't say that it will rain at 2:00 p.m. on a day that is two weeks away!

When you check out our website, the forecast for the first 5 or 6 days is looked at fairly carefully by our forecasters. However, Once you go out to 7 days and beyond, that is basically just what the computer models are forecasting, with no human intervention at all. Those models tend to flip and flop all over the place in the longer range predictions. That's why those forecasts seem to change so often.

I hope this helped.

Sincerely,

Dave Dombek
Expert Senior Meteorologist
AccuWeather.com

Accuweather

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Dave Dombek

Expertise

A weather enthusiast from an early age, Dave Dombek is now an AccuWeather meteorology expert.

Experience

Dave received his B.S. degree in meteorology from the Pennsylvania State University in May of 1980. Dave joined AccuWeather in July of 1980, beginning in the Snow Warning Service late that fall after his few month period of training. Within a short period of time, Dave got involved in radio broadcasting. He spent over 25 years broadcasting forecasts on radio stations throughout the Mid-Atlantic and Northeast states, and has also done newspaper forecasts and television briefings. Currently, Dave is the lead television briefer for all of AccuWeather's television clients in the northeatern quarter of the nation. In his daily forecasting routine, Dave helps coordinate the forecasts in the northeastern part of the country. He is also the Director of Forecaster Hiring and is in charge of hiring new meteorologists. Finally, Dave is the supervisor of the climatology department at AccuWeather. An avid outdoorsman, Dave enjoys hunting and trout fishing. He also enjoys watching football and is a student of history and current events. If Dave doesn't already have enough on his plate, he is married with two teenage daughters. He also leads a small Messianic congregation in the State College, Pa. area.

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