The Remnants of John Are Having Some Influence in the Southwest

Linda Lam
Published: August 10, 2018

John did not make landfall and its remnants have tracked west of Mexico's Baja California Peninsula, it is still influencing the weather in the Southwest U.S.

The remnants of John are well west of the Baja California Peninsula. However, moisture is surging into the Desert Southwest due to the large-scale counterclockwise wind flow associated with John.

Setup for an increase in moisture in the Southwest late week.

As a result, rain and thunderstorms have become more widespread and will persist through at least Friday.

Numerous storms fired up Wednesday and Thursday afternoon in New Mexico and Arizona.

Hailstones the size of ping-pong balls were reported near Flagstaff, Arizona, on Thursday. Flooding and debris flows affected a few homes near Ute Park, New Mexico, on Wednesday, according to a National Weather Service report.

Street flooding was also reported late Thursday into early Friday in Tempe, Arizona, and near Mesa, Arizona.


Current Radar, Watches and Warnings

Through Saturday, at least isolated thunderstorms will also extend into the mountains and deserts of southern California and southern Nevada, as well as portions of Colorado.

(MAPS: Weekly Planner)

Locally heavy rainfall will bring the risk of flash flooding over the next several days. NOAA has highlighted areas from central and southern Arizona into New Mexico as having a slight chance for excessive rainfall on Friday, where hourly rainfall rates could exceed one inch.

Most locations will generally see less than an inch of rainfall, but pockets of heavy rain are anticipated.


Rainfall Forecast

In addition to the threat of flash flooding, isolated severe thunderstorms cannot be ruled out. Damaging wind gusts will be the primary concern from any storms that turn severe.

Blowing dust could also affect the deserts of Arizona and New Mexico.

Even in areas where little to no rain falls, it will feel noticeably more humid as dew points have climbed into the 60s and 70s.

Early Wednesday, dew points in Southern California were in the upper 70s, including a 79-degree reading in Imperial, California, at 2 a.m.

Although it will feel more humid, the increase in moisture will help to keep temperatures lower across much of the Southwest. High temperatures will be slightly below average from southern Arizona into New Mexico Thursday through Saturday.

High Surf, Rip Current Danger

As with most tropical cyclones in the eastern Pacific Ocean, large swells generated by John will impact the beaches of Southern California into Saturday.

The high surf should peak Friday and Saturday, before tailing off, especially on south and southeast-facing beaches of L.A. and Ventura Counties, according to the NWS.

Potential beach impacts in southern California through Saturday night.

Dangerous rip currents are likely. Stay out of the water or swim near a lifeguard.

High surf has already claimed one life along the southern California coast this year, and 48 lives have been lost along U.S. beaches so far in 2018 due to either high surf or rip currents.

(MORE: Rip Currents More Deadly Than Tornadoes or Lightning in 2018)

Areas of minor coastal flooding area expected around the times of each evening's high tide through Saturday that could flood parking lots, beach walkways, and other low-lying areas near the beach.


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