North American Monsoon

ATS 553

Annual Distribution of Precip

Cold Cloud Frequency

Cold Cloud Frequency

In June:

Cold clouds (i.e., thunderstorms) occur in the central U.S. and along the cordillera of the Sierra Madre mountains.

Cold Cloud Frequency

Cold Cloud Frequency

In August:

Cold clouds (i.e., thunderstorms) spread throughout Mexico and extreme southern Arizona.

0Z images for 10 days in July 2004

Model of a Gulf Surge

Transports moisture up the Gulf of California, up the Colorado River valley, and into the American Southwest.

Model of a Gulf Surge

A Thermal Low exists over the deserts of Arizona and southern California.

Model of a Gulf Surge

To get a Gulf Surge, you need to create an area of High pressure near the southern tip of Baja California.

H

Model of a Gulf Surge

Low level easterly waves slide across Central America, bringing convection.

Model of a Gulf Surge

When the convection is across the mouth of the Gulf of California, a region of relatively high pressure is created DUE TO COOLING.

•Evaporation of raindrops

•Reduced solar heating

H

Model of a Gulf Surge

At Yuma, Arizona:

Winds shift out of the south-southeast.

Temperatures FALL.

Dewpoints RISE.H

Diurnal Cycle

High altitudes have a peak of convection in mid afternoon.

Low altitudes have a peak at night.