KOLD News 13 live, local and late breaking-Gulf Surge

Gulf Surge

A key component to the North American Monsoon is what is known as the gulf surge.  The gulf surge is caused by a difference in pressure from one end of the Gulf of California to the other.  On the northern side of the gulf (near Yuma and the Colorado River), there is an area of low pressure with temperatures near 105° F. 

On the southern end of the gulf there is an area of high pressure due to relatively cooler water on the western side of the Baja California and temperatures between 85-90°F.  The difference in pressures causes air to generally flow from the south of the gulf to the north into southern Arizona. 

The moisture is enhanced when a hurricane or tropical storm travels near the southern portions of the Baja California.  Some of the moisture from these storms will flow into the gulf and travel north.  The moisture will not travel east or west because the mountain ranges on either side of the Gulf of California act as a barrier and do not allow moisture to flow over them.   The moisture flows to the northern Gulf of California and is picked up by the low, situated over southwest Arizona. 

The low then pushes the moisture into the southeastern parts of Arizona.  In addition to the low, the four corners high further traps and pushes the moisture into the Tucson metro area.