Latest on Thu-Sun storm (two waves)

03/12/25 8am: Morning, forecast is on track for the approaching storm system which will impact the state from 5pm Thu to 5am Sun (two waves) with some moderate to heavy snow for the mountains (especially southern / western CO) and just some rain/snow showers for the front-range / eastern plains and some wind. Not a big update this morning as I'll be posting my snowfall map tonight but just a look at some of the latest model data.

Snow moves back into the San Juans after 4pm tomorrow (Thu), with some moderate / heavy snow down there into Fri am (with more snow into Sat): 6-12" by Fri am, additional 6-12" by Sun am (so totals of 12-20" for the San Juan ski areas)

Some snow showers move into the western north-central mountains (Vail to Aspen and CB) after 7pm Thu but will be light initially.

More moderate rounds of snow for all the north-central mountains (including the I-70 mountain corridor) from 3am Fri through 6am Sun (a break Sat am, more moderate snow Sat afternoon into Sun am as the second wave moves through): 4-8" through Sat am, with an additional 4-8" through Sun am. So totals in the 8-16" range by Sun am (highest amounts likely west of Vail Pass, closer to Vail/BC, Aspen/CB, Grand Mesa, FlatTops, secondarily maybe near Winter Park/Berthoud). I'll have a map tonight.

For Den/Bou and the front-range just a quick shot of rain/snow showers from about 3am-3pm Fri, best chances closer to 9am Fri. Probably just going to be rain for Den/Bou. Some snow for the Palmer Divide and foothills, won't be much (Trace-3" in those areas), otherwise no snow accum for Den/Bou and the urban corridor. Just turning very windy on Fri afternoon: northerly wind-gusts of 30-60mph, strongest east of Denver.

Looking ahead another potent winter-storm forecast to impact the state from about 12am Tue (03/18) through 6pm Wed (03/19)...that storm will be colder and looks like it will bring snow to both the mountains and Den/Bou and the front-range (could be several inches for the lower elevations / urban corridor), also another round of good snow for the mountains. I'll have more on that later.

First image loop shows the next 3 storms systems from Thu morning through next Wed via 500mb vorticity / wind from latest GFS. Second image shows forecast total snowfall just through 6am Fri from latest HRRR (just the very first part of the event). Images 3 and 4 show forecast total snowfall from now through 6am Sun from latest ECMWF and GFS (both waves combined), take amounts with grain of salt. I'll have a snowfall map tonight.