'Twas the night before Christmas when all through the house
Meteorologists were stirring, along with the mouse
The forecasts were hung by the chimney with care
In hope that deep powder, soon would be there
Now is not the time to settle your brains for a long winters nap. The latest forecasts from the Utah Snow Ensemble are the most optimistic I've seen all season for the central Wasatch, although that admittedly is a low bar.
Ignoring the outlier minimum and maximum forecasts, there is a tight clustering of forecasts producing 2.04 to 4.73 inches of water and 25 to 58 inches of snow for Alta-Collins by New Year's Day.
The first storm comes in with Santa's sleigh tonight, but excitement should be tempered with the fact that it's a splitter. The GFS shows it to be a "full latitude trough" on the west coast this morning with precipitation extending from off the SoCal coast all the way up into British Columbia.
But by Christmas morning it's split, although the GFS still gives some love to portions of Utah including 0.59" of water and 6.4" of snow for Alta-Collins.
After that, the storms come in frequency if not size. The GFS forecast for Alta-Collins shows both the water equivalent and snowfall (bottom two graphs below) "baby stepping" upward to 7-day totals of 3.32" of water and 35" of snow.
These aren't huge numbers, but change sometimes comes incrementally. I think we'll see better skiing with the approach of the New Year.
For the valley, this first storm is not only splitting, but offering up marginal temperatures for snow. The NWS forecast is as wishy washy as mine, calling for rain possibly mixed with snow for tonight and Christmas.
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| Source: NWS, grabbed 8:35 AM 24 December |
Will we have a white Christmas in the valley?
Only Santa knows.
I notice you put most emphasis on the HRRR short term and the GFS and ECMWF ensemble's longer term. Do you ever consider the NBM model? Have you any thoughts on its accuracy of SLR and accumulated precip vs the others?
ReplyDeleteThe NBM is the National Blend of Models. Rather than being a model, it is a blend of models, with that blend varying with forecast range.
DeleteI have used it some in the past, but it's not always convenient for me to use for a blog post. I also tend to favor the products we have developed in house. In them, we are testing and evaluating new forecast techniques, and that helps me to learn a lot.
My view is that there's no reason not to use the NBM if you find it helpful. It is an operational product provided by the National Weather Service.