wxgeek's weather-Spring Has Sprung - Meteorologically

Fri Mar 2

Second impulse currently moving across southern CO. System not as intense as earlier models predicted, but atmosphere is marginally unstable today, so as upper trough moves across late this morning into afternoon snow showers are likely south of I-70, with a chance farther north. Some convective snow showers possible, so a quick 1-2 inches of snow could fall in isolated locations today. In general, most foothill areas to receive anywhere from a dusting to an inch or two. Lesser amounts on the Plains. Activity should cease by sunset today. Most snow in the mountains today will be in the central and southern mountains moving into southeast CO this evening.

Attention then turns to winds. Latest model guidance suggests strongest winds won't form until early Saturday morning, around 3-6 am, and then winds remain very strong all day Saturday into Saturday evening. Looks like west to northwest winds of 30-60 mph likely with some gusts to 75 mph on Saturday. Highest winds will be in the mountains east of the Divide to the base of the foothills. Winds only breezy east of I-25 corridor. Some snow flurries will remain across the northern and central mountains west of the Divide on Saturday into Saturday evening. Winds will likely cause some blowing and drifting snow issues across N-S oriented roads like US 285, CO 93 and C-470. For skiers, expect lots of fresh powder on Saturday, but also lots of wind, blowing snow, and very high avalanche danger. Sunday is the much nicer day.

Sunday should be a glorious day across the state, lots of sun and only light winds with warm temps. These conditions should persist into Monday as well. Models indicate a weak upper trough will move down from the northwest on Tuesday afternoon, dragging a cold front across the state Tuesday evening. Currently looks like snow will remain west of the Divide across the northern and central mountains Tuesday afternoon into Tuesday night. Wednesday is a cool and breezy day across the state.

Long range models then change the global upper level pattern late next week, replacing the persistent upper ridge in the eatsern Pacific with an upper trough, which builds an upper ridge into the Inter-Mountain West. If this pattern verifies, we will see temps 10-20 deg above average by late next week into next weekend. Since this pattern has only recently been suggested, not a whole lot of confidence in it yet, but pattern makes sense with the onset of a more Spring global pattern, and is consistent with the Climate Prediction Center forecast for above average temps and below aferage precip in March across CO.
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"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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So the first day of Spring is March 1 from a meteorological perspective.

Attention today is on the current system battering CO. Cold front has just moved through the foothills and still impacting the Urban Corridor. Front has dropped a quick 1-3 inches most areas. Foothills currently seeing a break before the next band will impact the area this evening and tonight. This band currently over western CO and has closed I-70 through Glenwood Canyon due to heavy snow. I believe this band will drop another 1-3 inches across the foothills and Urban Corridor before midnight. NWS has now issued a Winter Weather Advosiry for the foothills and adjacent Plains through midnight.

We will see a brief break tonight (midnight to 6 am) before the second impulse moves across CO on Friday. This system will begin to drop heavy snow across the southwest and central mountains tonight, and then moves east across eastern CO Friday morning. Expect an additional 1-3 inches with this system Friday, with snow ending Friday evening. Total snow accumulation for today through Friday evening look like 3-6 inches for most foothills areas with up to 8 inches in favored spots. 2-4 inches expected across the Urban Corridor and Banan Belt areas. Evening commute today and Friday morning commute could be slower with slick roads in spots. This system has some instability associated with it, so some areas have the potential to see convective snow showers that can drop 1-2 inches of snow in 30 minutes.

Most snow ends by 6 pm Friday, and then stiff northwest Bora winds kick in Friday night into Saturday. Looks like winds speeds of 25-50 mph will buffet the mountains and foothills, with lighter winds across the Urban Corridor and Plains. High winds likely to persist through Saturday evening over the mountains and higher foothill areas. With recent snow, blowing and drifting snow could be a problem across roads, especially US 285, CO 93 and C-470. Some snow flurries likely to persist across the northern and central mountains Saturday west of the Divide.

Sunday looks sunny, warmer and only light winds across the state, and these conditions should persist through Tuesday of next week. Next system looks to impact CO Wednesday into Thursday next week, with another system possible next weekend.

As Spring has officially begun meteorologically, and as we have already seen this week, severe weather season is upon us. As these systems move east of CO, they will bring a threat of severe thunderstorms and tornadoes across the Plains and Southeast. As we progress later into the Spring, severe weather will move farther north into the Midwest and Mid Atlantic region. It's hard to say how bad the severe weather season will be this year, hopefully not as bad as last year, but we don't currently have a good method to predict the upcoming season. We do know that our weak to moderate La Nina is waning, with ENSO neutral conditions expected by this summer. Most models predict nuetral conditions into the Fall, with some models even predicting a weak El Nino by Fall. We will have to wait and see how that develops. The latest prediction from the Climate Prediction Center call for above average temps across CO for the March through June period, with below normal precipitation expected. Because we had such a snowy February that was associated with a MJO (Madden-Julian Oscillation), it makes sense we will likely see a drier than usual March, but if anotehr MJO moves back across the region we could see a wet April. March is climatologically the snowiest month for Denver, and April is the snowiest month in the foothills. So far to date, Conifer Mountain has received 148 inches of snow, which is 170% of normal trhough the end of February. We are still below our average of 175 inches so need more snow in March and April to keep the fire dnager low until the green up occurs in June. Most mountain areas are now at or slightly above average snow for the season. Foir severe weather, we usually begin to see our first thunderstorms in late April to May, with a peak in severe weather in June. Heaviest hail season in CO is June and July.
_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".