long range & historical data

Posted By: Norm201  Posted On: Apr 26th, 2011  Filed Under: Weather

Hi, I’m new here. I assume this may have been asked before, but I’m not sure how to search for it.

Correct me if I’m wrong but its my understanding that day to day weather tends to repeat itself year after year with respect to a long range forecast. Another words if any particular date is for sunny and warm, the odds are that it will be that way (or was that way) for  the most part in previous years.  Or if rain occurred on a particular day for 7 times in the past 10 years then that same upcoming date should have a 70% chance of rain, baring any particular weather phenomenon as the date approaches.  I realize this may be simplifying it too much but I trying to get a general trend.

My reason for asking is I want to make camping reservations for certain days and I must reserve at least 60 days in advance. I’m trying to increase my odds for good weather.

  1. Certainly the climatology of a specific region is taken into when compiling our long-range outlook. For instance . . . in July and August we sometimes will refer to the “monsoon season” in the Desert Southwest that produce localized heavy showers. But it is also true that we look at other factors that go into making our forecasts.

    Sometimes, when people ask about the methodology, I use a pot filled with water on a stove as an analogy. The pot is the Earth . . . the water is our atmosphere . . . the heat generated by gas flames or electric coils represents the Sun . . . and a wooden spoon represents the Moon.

    When we take into account solar activity and lunar cycles, it is dependant on how many sunspots and solar flares are occurring and at what phase the Moon is in and its distance from Earth. If a person varies the heat set on the stove and stirs the water a certain way, they will end up with a different variation; the same holds true with our atmosphere: an active Sun usually correlates to hotter temperatures . . . a quiet Sun (less sunspots and flares) means cooler conditions. If the Moon is at full or New phase around perigee, tidal forces are greater (more mixing) as opposed to a quarter Moon at apogee (less mixing).

    So . . . if we say that on a specific date in February there is a chance of a blizzard, it isn’t because a blizzard has occurred on the same day in 7 out of the last 10 years! It is based on a blend of these solar and lunar cycles.

    Put all these variations together (along with climate trends) and you come up with a forecast.

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