Why does it snow so much in Flagstaff? Here’s what to know
Flagstaff may be in a state known for its scorching summers and years-long droughts, but it is one of the snowiest cities in the United States.
- After a week of persistent warm weather, a storm system is expected to bring rain, not snow, to Arizona for Christmas.
- Flagstaff and other high-country areas are also too warm for Christmas snow, with precipitation expected to be mostly rain.
- The same weather pattern is bringing heavy rain and potential flooding to Southern California and parts of the Northwest.
Arizonans dreaming of a white Christmas will likely have to settle for rain this year as warm temperatures persist.
A storm system off the West Coast is expected to funnel moisture into the state later this week, giving much of Arizona chances for rain around Christmas Eve and Christmas Day.
The unsettled pattern could bring measurable rainfall, but temperatures are expected to stay too warm for snow, even in the high country. Arizona won’t get the soaking Southern California is expecting from incoming atmospheric rivers slamming the coast, but that same system will push moisture into the Southwest.
“Unfortunately, no white Christmas. I’m sorry to be the bearer of bad news,” said Ted Whittock, a meteorologist with the National Weather Service in Phoenix.
In Phoenix, rain chances as temperatures cool from record highs
In Phoenix and the lower deserts, Christmas week will start off unusually warm before gradually cooling as rain chances increase.
Phoenix could break a daily temperature record for the second day in a row on Monday, Dec. 22. The current record is 79 degrees, with a forecast high of 82. A high of 81 degrees on Sunday, Dec. 21, broke the daily record for the third time this month.
But the weather should shift as a low-pressure system moves in from the Pacific.
“We’ll see a strong low-pressure system move in just off the West Coast and bring plenty of moisture into the region starting tomorrow,” Whittock said. “As a result, we’re going to see periodic rain chances this week.”
Forecasters say there will be two main windows for rain: late Tuesday into early Wednesday and again from Christmas Eve into Christmas Day.
Temperatures will start to trend downward midweek, with highs potentially dropping into the 60s and low 70s by the weekend.
Rainfall totals in the Valley could add up to around a half-inch or more in spots.
High country: Flagstaff is Arizona’s snow capital. Here’s why
In Flagstaff, mostly rain early with uncertain snow chances later
Up north, Flagstaff will also see an unsettled and warmer-than-normal Christmas week. But snow lovers may be disappointed.
“It’s very warm for this time of year compared to what it usually is in December, so we’re expecting this week’s events to mainly be rain instead of snow,” said Jacob Lewandowski, a meteorologist with the National Weather Service in Flagstaff.
The first chance of rain in the forecast is Tuesday, Dec. 23 in the evening. Snow levels are expected to stay high through midweek, generally between 9,000 and 10,000 feet. That puts Flagstaff below the snow line during the initial rounds of precipitation.
Chances for snow could increase later in the week as cooler air moves in, but confidence drops significantly after Wednesday.
“The chances for snow start increasing by Thursday and Friday, but it’s still a lot of uncertainty with it,” said Lewandowski. “It’s just how warm it is through the week and whether it’s going to be all rain or a little bit of snow mixed in. Most likely not a white Christmas, though. It’s too warm.”
Atmospheric rivers hit the West Coast as much of the U.S. stays warm
The storm system affecting Arizona is part of a broader pattern impacting much of the western United States. Atmospheric rivers, or long plumes of moisture from the Pacific, are expected to bring heavy rain to parts of coastal California this week.
“The atmospheric rivers are going to impact Southern Calfironia, particularly on Wednesday,” Whittock said. “This is an especially impactful system for people that are traveling to and from Southern California, especially coastal areas.”
Forecasts from the National Weather Service in Los Angeles show an extended period of heavy rain expected from Tuesday through Saturday, with 4 to 8 inches of rain likely across coastal and valley areas. Prolonged rainfall could lead to flooding and debris flow concerns, especially in burn scar areas.
Unusual weather isn’t limited to just the West. Much of the United States will have a warmer than normal holiday, with some areas experiencing their warmest Christmases on record.
A northward shift in the jet stream over the middle of the country is allowing warmer air to spread east, causing above-normal temperatures. From the Rockies to parts of the Appalachians, temperatures could reach 15 to 30 degrees above average for Christmas Day.
So whether it’s rainy or warm, much of the country will miss out on a snow globe Christmas this year. In Arizona, that likely means a damp holiday instead of a snowy one.
Hayleigh Evans writes about extreme weather and related topics for The Arizona Republic and azcentral.com. Email her with story tips at hayleigh.evans@arizonarepublic.com.
