As we discussed yesterday, there’s good agreement between models that we’ll see some snow across northeast Colorado Thursday night and into Friday. The question now becomes, how much?
Overnight the National Weather Service issued a Winter Storm Watch for the I-25 urban corridor and Front Range foothills. The watch indicates they think this storm could deliver 6 - 8” for Denver, with 8 - 14” inches for foothills communities. We think, while not unreachable, this is a heavy handed initial forecast, so for the time being you’ll see our numbers lower than this, especially for Denver proper.
An unweighted QPF chart of the 00z and 06z model suite produces 5.88” of snow for KDEN, assuming 15:1 snow water equivalent. Throwing out the upgraded GFS, the 12z suite is very close to this at 5.67”. All models, outside of the EURO are in roughly the same ballpark for Denver, with 0.35 to 0.5” QPF across the city from Thursday evening through Friday. Not bad right?
QPF table Denver
Our current thinking puts Denver in the 2 - 5” snowfall range with this system, with 4 - 7” locally. We’d like to see some of the lower end models come up a bit, and also need to watch carefully where the heaviest snowfall band sets up. A few recent runs by the GEM, and pretty consistently from the EURO have heaviest snowfall totals north of the metro area. There’s still plenty of time to tweak these numbers a bit, so we’ll see what 00z runs look like tonight. You can see in the snowfall forecast map above, we do think the southwestern and foothill communities will do well with this system.
Given that this system will likely favor the Northern Front Range, locations farther south will see less snow. Folks on the Palmer Divide will obviously be in the 2-6” range, with locally higher amounts west of I-25. However, Colorado Springs will likely see less snow and end up in the 1-3” range with even less snow farther south. Mountain locations to the southwest of Pueblo do have a chance for higher totals. However, how much is still somewhat in question…
The interesting thing about this pattern transition (which we talked about a few weeks ago) is how much colder we will be. After a “mild” Christmas Day, the pattern favors a pretty significant intrusion of Arctic air. The pattern will also bring several different shots of Arctic air to the region through the end of 2014. While it is still a ways out, some of our computer models are suggesting the coldest air of the season later next week.
We’ll continue to track this system for you over the next 24 hours. We’re working with a skeleton crew here over the Holiday, so we’ll see when we can get another update out. At the very least we’ll keep the snowfall forecast map (above) updated, and likely pass along any brief updates via our “Live Blog” (these are not emailed out). If there are any big changes to the forecast going into Christmas day, rest assured we’ll pass those along. If you’re not subscribed, now is a great time to do so!
Wishing everyone a Merry Christmas and Happy Holiday, here’s to hoping for a white Christmas (night!).