Fig. 4.—Straight Isobar Prognostics.
Near the high pressure the sky is blue, then as we approach the low pressure feathery cirrus, or some form of windy sky, makes its appearance, while a blustery wind whirls the dust, or blows the soot down; and animals turn their tails to the wind to avoid its force on their faces:
When chimneys smoke and soot falls, bad weather is at hand. The whistling of the wind heard within doors denotes rain.
When sheep, cattle, or horses turn their backs to the wind, it is a sign of rain.
Getting still nearer the low pressure, the sky is found to be gathering into hard stratus, at first with chinks between its masses, through which divergent rays stream down under the sun, which is spoken of as “the sun drawing water.” Sometimes, especially in winter, these rays are lurid, and are referred to in the following prognostic:
Along the north shore of the Solway, from Dumfries to Gretna, a lurid appearance in the eastern or southeastern horizon, called from its direction “a Carlisle sky,” is thought a sure sign of coming rain. They describe it as lurid and yet yellowish, and the common saying is:
The Carle sky
Keeps not the head dry.
At the same time there is often great “visibility” with a hard overcast sky, and moderately dry air, in which the stratus seems to play the part of a sunshade, for as soon as the sun comes out the clearness of distant objects diminishes. This visibility must not be confounded with the visibility already described with a cloudless sky, which occurs with wedge-shaped isobars. Simultaneously we often find “audibility.”
If the noise of a steamer or railway train is heard at a great distance, rain is predicted.