on August 30, 2010 by admin in Forecast, Comments (4)
How reliable is a 10-15 day weather forecast?
I am going to CA in about a week and a half– I looked up accuweather’s 10-15 day forecast and it’s rainy! 
Is there a chance this could change or are weather forecasts that far in advance pretty reliable?
Jack Knife
August 30, 2010 @ 12:32 am
I don’t even trust the forecast for tomorrow.
e
August 30, 2010 @ 1:02 am
I don’t think weather forecasts that far in advance are reliable. I would keep checking the weather until you go, and even after you fet there.
Anonymous Viking Reborn
August 30, 2010 @ 1:13 am
Nope. There’s a mathematical limit to how accurate you can make a weather forecast. 15 days in the future is far beyond the realm of certainty because weather systems have a lot to do with these things called Lorentz attractors. The sunniness of California 15 days in the future may not depend on whether a butterfly is flapping it’s wings in Japan, but it may very well be influenced by how much methane the dairy farms of Hawaii produce and exactly when a single thermal lifts off from the ground.
There is a fairly good chance that the forecast will change. How good a chance? About 40% or better.
Paul in San Diego
August 30, 2010 @ 2:00 am
A weather forecast more than 7 days out is pretty much useless. You can say what the general climate will be. But, what the weather will definitely be from one day to the next is virtually impossible to say beyond about 7 days. That said, it is very likely that it will be raining some time during your stay.
We’re experiencing an El Nino this year, which means rain is more likely in California, especially from February through April (which is typically the rainiest time of year, even without the El Nino). And, we’re currently in a high pressure offshore flow condition this week, with showers likely Saturday and Monday. With these kinds of weather patterns, we typically see a dry period of about a week, followed by an unsettled period of a week or more.
Unsettled weather just means that conditions are conducive to rain and storms. So, within the next 10 – 15 days, there’s a good chance we will see some rain out here. When exactly and how much? We won’t know until about 5 – 7 days out, at the earliest.