A model – not a model | News


It has been hard not to feel at least a twinge of envy about the massive storms that have recently swept through the northern part of our state. They just seem to keep coming.

After a brief break on Thursday, “snow returned over (the) mountains near and north of I-70 and about Vail east to the Continental Divide,” said Friday. morning forecaster Joel Gratz on his website, OpenSnow.com.

The next chance of humidity in Colorado won’t arrive until later this week.

“Tuesday looks pretty dry,” said Matthew Aleksa, meteorologist in the Grand Junction office of the National Weather Service. “Maybe the far northern mountains, including Wyoming, will see something. But it will be mostly dry for us, unfortunately.

By “us” Aleksa was referring to the people of southwest Colorado.

“Another system is expected to drop on Thursday, and it could be far enough south to impact the San Juans,” Aleksa added. “But it moves fast, and models change when it comes to its placement.”

“Then,” Aleksa continued, “we go into that slightly drier westerly flow, except for that possibility of humidity on Thursday. Beyond that, we look at the end of our model” at the office. from the local National Weather Service, “” which is out until Monday, November 22. It shows a northerly flow over the western half of the United States, which does not bode well for snow.

The long-term outlook for heavy snow is so-so: “There is a greater likelihood of above normal temperatures and an equal chance of above or below normal precipitation” during the 90 day period between November and January, Aleksa continued. .

The National Oceanic and Atmospheric Administration (NOAA) on Thursday raised the odds of a La Nina weather model to 90 percent from 87 percent (its most recent prognosis, in October). The seasonal climate model – Spanish for “little girl” – develops over the Pacific Ocean and generally portends wetter conditions for the northern United States

“It tends to favor the mountains of northern Colorado,” Aleksa said.

According to NOAA, there is a 50 to 50 chance that La Nina conditions will prevail until spring, which gives hope for sublime powder at the end of the season (March is the snowiest month in Colorado).

Also hopeful: Aleksa pointed out that La Nina is a weather model, not a model. “That doesn’t mean the San Juan won’t see snow,” he said. “They can.” These mountains are “just not being favored for higher amounts of snow” over the next 90 days.

Which doesn’t mean there won’t be big storms in the next three months either. “It’s just a question of the storm trajectory,” Aleksa said. “La Nina storms tend to hit the northern and central mountains and miss the San Juan. But that doesn’t mean we can’t get such systems: we can. It’s just that overall, in winter terms, “at least until February,” the northern mountains tend to be more conducive to humidity. Not when it comes to each individual storm, but in general the jet stream is positioned across the northern Rockies. But it can also dive further south and bring storms to the San Juan.

The snows we have had recently helped alleviate “a bit of the drought,” Aleksa admitted. “A few storms producing good humidity will help, but drought is more of a long-term thing. The area north of I-70 has been classified by the National Drought Monitor as D4, or “exceptional” drought. It’s now over, but we’re still in D3 (“Extreme”) drought here. “

Aleksa described the drought conditions in the San Juan as moderate, “but the Four Corners are experiencing extreme drought,” he said. Recent snowfall has helped, but not significantly: “They still haven’t done much damage. It will take a wet season, and I mean a lot, to reduce those drought levels. We still have a lot to overcome.

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