RENO, Nev. (AP) — Unusually cold weather is expected to continue across most of the Southwest into next week from the Sierra to New Mexico, the National Weather Service said late Saturday.

Lows well-below zero Fahrenheit (-18 Celsius) are forecast in parts of Nevada and Arizona, and more snow is expected in some areas around Flagstaff that already have received their most January snow in four decades, the service said.

Wind gusts could top 100 mph (160 kph) over Sierra ridgetops around Lake Tahoe Sunday as the front blows in with wind chills as low as minus 25 (-32 C).

Temperatures are expected to remain 10 to 20 degrees below normal across most of the region into Tuesday.

“Confidence is growing for a winter storm system to impact a large section of central and eastern New Mexico Monday through Tuesday morning,” the National Weather Service in Albuquerque said Saturday.

Sub-zero lows early Saturday — minus 17 (-27 C) at Mormon Lake south of Flagstaff, Arizona — stretched as far north as Ely, Nevada on the Utah line where it was minus 9 (-23 C).

Grand Canyon Airport in Arizona reported 14 below (-26 C), Williams minus 4 (-20 C) and Flagstaff Airport minus 3 (-19.5 C). The low dipped to minus 5 (-20.5 C) in Elko, Nevada, the teens in Reno, 38 (3 C) in Las Vegas and 36 (2 C) in Scottsdale, Arizona.

Freeze warnings were in place for much of south-central Arizona south of Phoenix, including Paz County where a hard-freeze was possible early Sunday.

A couple inches of snow was expected in the mountains around Flagstaff, where the coldest weather system of 2023 was expected to move across Sunday night into Monday, the service said.

With 10 days remaining in the month, Flagstaff already has received 57.9 inches (147 centimeters) of snow — the most January snow since 1980 and fourth most ever in records that date to 1898.

The National Weather Service said on Saturday “third place is within reach” — 59.4 inches (151 cm) in 1979. The most was 104.8 inches (266 cm) in 1949.

In Nevada, lows were expected to remain in the low 30s (near zero C) in Las Vegas into the middle of the week, with single digits both below and above zero in Elko and lower teens in Reno.