Facts of the Matter
Facts of the Matter
Weather may never
be predictableEveryone talks about the weather, but no one does anything about it! The problem is that no one can. Not yet, probably never! No one can even tell you for sure what the weather will be tomorrow, although meteorologists can give a better forecast now than at any time in the past.
What we call weather is the result of complex interactions of heat and water vapor, driven by heat from the sun, spun into whirling continental-size air masses by the earth's rotation. Some of our island weather is local. It is the result of winds blowing over mountains, causing clouds to form as water vapor in the air condenses in the cool air of higher elevations. These produce the "windward and mauka showers" we hear about on the news.
These winter rains we've been having the past few weeks are a different story. They are the product of huge interacting masses of warm tropical air and cold polar air. When warm moist air and cold dry air come together, thick masses of clouds, severe winds and heavy rainfall are produced along the front that separates the two air masses. Frontal storms move from west to east as they form and dissipate. They are more heavily concentrated in the higher latitudes, but the tails of their characteristically comma-shape clouds sweep from the west across the Pacific Ocean and bring us the rain and mild cold of our subtropical winter.
A storm's intensity and motion across the land are controlled by several factors, but one of the most important is the position of jet streams. Jet streams are fast-moving, tubular currents that snake through the upper troposphere, the lowest layer of Earth's atmosphere where all weather occurs. When a kink in the jet stream is directly over the low-pressure center of a frontal storm, the storm can intensify as the jet stream "sucks" air from near the surface.
You might think such things would be easy to forecast, but this is not the case. Weather at one place is not independent of conditions around the globe. To make good predictions, meteorologists use computers to simulate future conditions.
The effectiveness of these simulations is limited. One reason is the limited power of computers. Even the most powerful supercomputers can process only a fraction of the world's weather, and only for a fraction of Earth's surface.
Another limitation is the sparsity of temperature, pressure and water vapor data. Most of Earth's surface is ocean, where most of the heat and water transfer between the surface and the atmosphere takes place. Even if there were more weather stations on the oceans, today's supercomputers could not handle the load.
Number-crunching limitations notwithstanding, it appears we may never be able to predict the weather with anything close to 100 percent accuracy. The emerging science of chaos tells us we can never know weather conditions accurately enough to be able to predict the weather beyond a couple of weeks, regardless of the density of the data or the power of the computer.
Although the science of forecasting is getting better, there's not much hope for relief from the cold, rainy winter. But compared to the snow falling in Utah, it's relatively warm outside your door.
So get under the blankets and remember, lucky you live Hawaii!
We could all be a little smarter, no? Richard Brill picks up
where your high school science teacher left off. He is a professor of science
at Honolulu Community College, where he teaches earth and physical
science and investigates life and the universe.
He can be contacted by e-mail at rickb@hcc.hawaii.edu