National Weather Service United States Department of Commerce



Probabilistic snowfall forecasts will resume this fall.


The purpose of these experimental probabilistic snowfall products is to provide customers and partners a range of snowfall possibilities, in complement to existing NWS deterministic snowfall graphics, to better communicate forecast uncertainties during winter weather events. For more information visit this project's Product/Service Description Document, and please provide us your feedback here.
Other Snow/Ice Information
Storm Track Onset of Wintry Precipitation Reported Snow/Ice Totals
Storm Total Ice Graphic
Winter Precipitation Onset
Latest snow report
What's this? What's this? What's this?

Low Tracks Graphic

The graphic depicts the forecast location of significant surface lows impacting the 48 contiguous United States in 12 hour increments out to 72 hours into the future.

The low position and track forecast by NCEP WPC meteorologist is in white. Each low position is accompanied by a lead time (Eastern Time). The circles around each low represents a 75% probability the observed low will be located with the circle. Note: The probability is derived using previous season's verification data. For reference, existing surface lows are depicted with a red marker without yellow circles.

Precipitation Onset

Most likely time of winter precipitation onset (snow, sleet, freezing rain). Rain is not included here. This information is provided when we issue a Warning or Advisory for expected snow or ice accumulation; typically six to 24 hours in advance. Times are only given for places that are under a Warning or Advisory. They will be blank in areas outside Warnings or Advisories.


As snow and/or ice reports come into the NWS (you can email reports to or Tweet to @NWSBoulder), we will pass them on here. With the map linked here, and the supporting reports below it, you can keep tabs on how much has fallen.


Boulder, CO Products
Long-Range Forecast
Days 4-5 Forecast Precipitation Days 6-7 Forecast Precipitation
Days 4-5 Precip Days 6-7 Precip

Days 6-10

Temperature Precipitation
6-10 day temperature 6-10 day precipitation

Days 8-14

8-14 day temperature 8-14 day precipitation

Week 3-4



Week 3-4 Temperature Week 3-4 precipitation