The hottest days on record in Southern Arizona and Nevada are expected on Thursday, with highs in the upper 60s in the desert southwest and highs in parts of Nevada expected to peak in the middle of the day.
Temperatures will be in the 90s and in the mid-to-upper 70s in both areas, and a low of just 20 degrees is possible.
The National Weather Service in Las Vegas said it will record more than 300 millibars of rain for the next 24 hours.
It is the most rain the region has ever seen on record.
That includes a total of 1.5 inches in the San Gabriel Mountains.
It was just shy of a record.
Tempering temperatures of around 80 degrees will prevail in parts, and the weather service said the chance of thunderstorms will be near normal in parts.
The National Weather System Center in Tucson has a heat index of 75, and this week’s high is at 87.
At this point, there is no official forecast of the potential for thunderstorms, but the chance is low.
The weather system also is likely to create some dust storms and will bring some scattered hail, the weather center said.
The low will last about a week, and it could continue for a couple of weeks.
The next chance to get an opportunity for a storm is Wednesday afternoon.
The next high temperature is expected to be about 40 degrees in Phoenix and Phoenix-area.
Tempe is expected on Wednesday for a chance of a high of 43 degrees, and parts of the Arizona-Nevada border are likely to get a chance at a high around 40 or 40-40.