Should
I leave the top and doors home today? This is a question that
a lot of 4x4 owners ask themselves before a nice day of trail
riding. Wouldn't it be nice to know what weather is expected during
the day without having to carry around a mobile digital satellite
system in the Jeep with you?
Sure,
NOAA weather radios are great things to have on the trail, but
in some cases you need more information - especially when your
trail ride is taking place somewhere that is not near a major
metropolitan center, such as Tellico. Wouldn't it be nice if you
had the tools with to you accurately forecast the weather to see
if your information concurs with The Weather Channel or the NOAA?
Most
of this information is available around you but you do need to
know where to look. For instance, did you know that you can forecast
the weather by looking at the smoke from a campfire or looking
into a cup of hot java? It's true! For those of us who are addicted
to electronic gizmos, there is a great miniature portable weather
station that weights only ounces and measures just a few inches.
We'll get to that later.
In order
to make an accurate forecast of the weather you need to understand
some of the very basic principals of weather and weather systems.
We'll keep the details limited to just what you'll need in this
article. For a more detailed explanation of weather systems and
how to make a more accurate forecast, I suggest reading Weather
Forecasting by Michael Hodgson (isbn 0-7627-0478-0).
Before
we get into where wet and dry weather comes from and how you can
forecast them, we'll need to understand the difference between
warm and cold air masses and high and low pressure systems.
In
the Northern hemisphere cold weather air masses generally travel
from North to South. Cold air warms as it travels over the land
and this causes the air system to become unstable. With cold air
systems the weather can change very quickly. Warm air masses are
more stable than cold air masses and the weather that is created
from the warm air masses is more likely to stay around longer
than weather created by cold weather systems. Warm air masses
are generally swept into the country from South to North.
High
pressure systems are associated with cold air masses while low
pressure systems are associated with warm air masses. "High" and
"low" pressure systems are so named because of the amount of pressure
that each system puts on the ground that can actually be measured.
As a rule heat rises and cold sinks. Since cold air is heavier
than warm air, cold air will place greater pressure on the land
below it. The amount of pressure that is placed on the ground
is measured with a barometer.
By
watching the change of barometric pressure one can determine what
kind of weather you can expect during the day. Simply seeing what
the current pressure is may not help that much. You need to watch
the pressure change over time in order to properly forecast the
weather. Having to write down the pressure of analog barometers
is somewhat of a pain. You always need to have a pen and paper
around to compare pressures and if you lose the scrap of paper
you were writing on, you are out of luck. You could always write
the pressure, date, and time in permanent marker on the side of
your 4x4, but I think most people wouldn't go this route and you'd
probably misplace the permanent marker anyway!
In order
to make an accurate forecast of the weather you need to understand
some of the very basic principals of weather and weather systems.
We'll keep the details limited to just what you'll need in this
article. For a more detailed explanation of weather systems and
how to make a more accurate forecast, I suggest reading Weather
Forecasting by Michael Hodgson (isbn 0-7627-0478-0). 