WEATHER TYPES ON THE PACIFIC COAST. 81 



and in the San Joaquin Valley. The temperature through- 

 out the coast is about normal. It is only when a subsidiary 

 low is developed in southeastern California, locally called a 

 *' Sonora Storm," that rain spreads over the southern part 

 of the State, being generally of short duration. See Plate 

 III as an example of the conditions existing during this type. 



INTERIOR ANTI-CYCLONIC. 



This second type closely resembles the preceding in 

 that the interior high is well marked, but differs in that 

 the low upon the coast is less in depth. This type pre- 

 vailed from November 11th to 15th; November 25th to 

 December 6th; December 14tli to 26th; January 27th to 

 February 12th. It is characterized by a high barometer 

 (about 30.30 inches) over Utah, Nevada and Southern 

 Idaho. The accompanying low barometer on the north- 

 ern coast drops down frequently to 29.70, and is cen- 

 tral west of Washington Territory. These lows appear to 

 beat against the high, the low area often dropping down for 

 a short time nearly to Cape Mendocino. At other times 

 they push the high southerly over Arizona and pass east- 

 ward beyond our boundary. Again when the surge of high 

 pressure is very great over Idaho, a low often pushes upon 

 it from the southwest coast of California, at which time rain 

 may occur in light showers on the southern coast. The 

 rainfall, except as just mentioned, never passes south of 

 San Francisco, and is generally limited to light showers in 

 Oregon and Washington Territory. Gales are very strong 

 from the southeasterly at Cape Mendocino and at the mouth 

 of the Columbia River, north x)f which they come more from 

 the south. The temperature is usually high, and at times, 

 of steep gradients, from Nevada southward; near Los An- 

 geles, the warm " Santa Anna" winds may occur. Plate III 

 serves to illustrate this type if the pressure over Idaho and 

 Nevada is considered about 30.30, and the low on the North 

 Pacific Coast about 29.80 inches. 



