Reading nature’s signs
Although no method of forecasting is infallible, even simple observations may indicate what weather is coming. There’s truth in the old saying “Red sky at night, sailors’ delight; red sky at morning, sailors take warning.” In the Northern Hemisphere most weather comes from the west, and the setting sun shines through tomorrow’s weather. If the distant air is dry and clear, the sunset will be red, indicating a fine day to come. Conversely, a red sky around the rising sun shows that dry, clear air has passed to the east, possibly heralding wet weather.
Highs and lows
The weather moves in masses of air, which are propelled into and around pools and eddies of high and low pressure. The air in the masses circulates clockwise away from the center of a high-pressure area, or high. It circulates counterclockwise toward the center of a low-pressure area, or low, where it escapes upward, cools, and leaves its moisture in the form of rain or snow. A high usually means good weather; a low, poor weather.
Changing winds announce a change in pressure. Awi de deviation from the prevailing wind direction indicates a low. If you don’t know the prevailing wind directions for your area, consult your weather bureau or a detailed atlas. Often the winds of a low overturn leaves so that you see their backsides. Reading the clouds
Clouds are among the most helpful weather indicators. They are generally classified as high, medium (alto), or low in altitude, and are divided into three basic types: cirrus (wispy or feathery), cumulus (large and fluffy), and stratus (flat and layered). The Cumulus Cumulus with thunderhead types are sometimes combined and any of them may become a rain cloud.
Isolated cirrus clouds indicate the advance of wann, moist air, but not necessarily rain. If they become denser or broader, however, a low is probably on its way. When cirrus clouds develop into long, straight rows (cirrostratusclouds), forming a halo around the sun or moon, a prolonged period of rain or snow may be on its way.
Low-lying, gray stratus clouds that cover much of the sky usually bring mists, drizzle, or rain. Higher stratus clouds (altostratus) that are flat, gray, and featureless and through which the sun can be seen dimly, mean a few hours of rain or snow, possibly heavy. Cumulus clouds are favorable signs unless they darken and descend. If a cumulus cloud develops a towering thunderhead, a storm is brewing.
Reading nature’s other signs
In the humid atmosphere of a low, smoke stays close to the ground, distant objects look closer, sounds seem louder, and birds and insects turn silent. One or two of these signs indicates a mild low. A combination of most of them indicates a heavy storm developing.