Fox News Weather Center

Sporadic Storms, Blanca to Douse California to Colorado Through Midweek

A plume of moisture, some associated with the remnants of Blanca, will continue to affect parts of California and the Southwest states this week.

The moisture will bring rounds of showers and thunderstorms on a nearly daily basis that will peak during the afternoon and evening hours.

The showers and storms are surging well north of Mexico and into parts of California, Nevada, Utah, Colorado, Arizona and New Mexico.

According to AccuWeather Senior Meteorologist Ken Clark, "It is highly unusual to get tropical moisture this far north this time of the year."

In addition to showers and storms, the tropical moisture will bring higher humidity levels and lower daytime temperatures to the region through midweek.

Despite the tropical connection to the moisture, the rain has been and will continue to sporadic west of Colorado and New Mexico.

"I don't foresee any particularly large areas of heavy rain in California and Nevada in the pattern," Clark said. "The only exception might be part of the Sierra Nevada, especially on Thursday."

As a result, no significant impact to the drought in California and Nevada is expected.

Rainfall on a highly localized level can be heavy enough to cause isolated incidents of flash flooding and debris flows. The terrain in the region favors rapid runoff of rainfall that can quickly fill arroyos and wash across roadways with little notice.

Hikers and other outdoor enthusiasts in the region should be on the alert for rapidly changing weather conditions. Rapidly building storms during the midday hours can begin to produce lightning with little notice.

Dry air will begin to progress slowly from west to east across much of the Southwest during the latter part of the week and into the weekend. An uptick in temperatures is expected as the clouds and showers clear.

The daily downpours that the Southwest is experiencing are not the beginning of the monsoon, but rather an abbreviated visit by tropical moisture. On average, the monsoon does not kick in over the Southwest states until July.

"This will likely be the caboose for the rainfall in much of the Southwest, until the monsoon can get established later in the summer," Clark said.

Typically, the monsoon has little impact on California and is more focused toward the Four Corners states.

According to AccuWeather Chief Long Range Meteorologist Paul Pastelok, "The prevailing dry ground and anticipated weather pattern through much of the summer will cause the drought to worsen and temperatures to climb in California."

A southward dip in the jet stream, a river of high-speed air aloft, has contributed to below-average temperatures in much of the Southwest during May and early June.

"The jet stream will retreat well to the north over the West and will allow more frequent bouts of heat and building drought in the Northwest as well," Pastelok said.

Significant relief from the drought will have to wait until later in the fall and winter, provided El Niño remains significantly strong.