Sunday Update: Snowfall Forecast Update, Storm on Track

We're coming down to the wire on very tricky forecast for the next 24 to 36 hours. As we've been saying all week, this system has the potential to go a number of ways. Generally speaking, models have upped snowfall totals across the forecast area for this afternoon through Monday evening. The greatest potential for heaviest snow will be for areas in, and immediately adjacent to, the Foothills.

The National Weather Service has issued a Winter Weather Advisory for Denver through Monday afternoon. There will be a chance for snow off and on from early afternoon Sunday through much of the day Monday. Snow will be heavy at times.

Snowfall Forecast
We've upped totals a bit from our discussion yesterday. For Denver we're going with 2 - 5" north and east, to 3 - 7" south and west. While some models have come in with quite a bit more snow than this for Denver proper, there's enough uncertainty that we'll keep on lower-end for broad-brushed forecast for now. The EURO remains far less intense as compared to the GFS, with the Canadian and UKMET somewhere in between. 2 - 5" should cover the 'bust low' potential of 1 - 2" for the city, and 'bust high' potential of 6"+. It is important to note that with all these forecast totals, locally higher amounts will be possible where banded snowfall occurs.

We can be a little less wishy-washy for those living closer to the foothills, and in the foothills where the snowfall forecast is higher confidence than across lower elevations to the east. Some foothill communities could reach or exceed a foot of snow.

Timing and impacts
We're already feeling the effects of our storm system across northeast Colorado this morning. Temperatures are near 40 across the Denver metro area, but the clouds have thickened and north of the city temperatures have already dipped below freezing as our storm sytem digs southward.

18z Obs and GFS 6 hour forecast | Univ Washington

The chance for snow increases this afternoon and this evening, then again Monday. This is a longer duration storm, so not all snowfall will come in a brief window as we sometimes see. I think we'll know pretty quickly by this evening if this storm will end up on the higher or lower end of snowfall forecasts.

If you are traveling on the roads over the next 24 hours, please be prepared for winter driving conditions. Greatest road impacts will be from Denver westward.

Snow will decrease in coverage and intensity as we head into Monday evening, with drier conditions returning for Tuesday.

Additional thoughts
The nature of these systems is that some are going to be disappointed and some will certainly not. While tricky to pin down exact placement of heavier snow bands, I do like this setup for someone to do pretty well with snow. As we saw with out last northwest flow event and convection – it doesn't take much for any give location to overperform, while others see very little snow.

Overall I think this fits very nicely with our narrative, and if you're to believe the medium range models, we've got more chances for snow in the forecast. If you've been waiting for winter to return, this is a very exciting time indeed.

We'll offer updates as needed, and if need be post additional snowfall forecasts / update on our Live Blog through the duration of the storm. If you are not subscribed to Weather5280, now is a great time to do so! Also, don't forget to follow us on Twitter @weather5280.

Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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