The 7 day period stretching from last Friday to this Friday may go down as one of the best for the Cottonwoods in quite some time (at least since last season…). We’ve already gotten the “dirty” work out of the way with this past storm putting down extraordinarily high amounts of snow water or SWE (> 5 inches in the Upper Cottonwoods) cutting what was a 40% deficit into a surplus!!! The news gets better, though, and for Christmas day things are looking downright scrumptious.
A MUCH COLDER trough (than the previous system) will bring a strong cold front in from the NW with most of the precipitation falling during and after the frontal passage. Winter will finally truly arrive for all of Nrn Utah early on Christmas morning with snow levels crashing down to valley floors, which has prompted the issuance of Winter Storm Watches. The Cottonwoods will likely fair the best once again since at least a portion of the post-frontal period will see NW flow. Here are some of the model snow water or QPF totals: GFS = .6″ NAM = .8″ ECMWF = .8″ 4km NAM = > 1.15″
Like I already mentioned this storm will be COLD with densities around 5%, our first true blower powder of the season. Snow will intially be higher density but the switch will be very quick as the trough ushers in much colder air aloft. Thus .6″ of QPF would yield appx. 12 inches of snow. With all of this said I’ll stick with Matt’s numbers from yesterday:
12 – 24 inches in the Upper Cottonwoods
8 – 16 inches in the Northern Wasatch
6 – 12 inches in Park City
Small caveat: As is often the case with COLD NW flow storms, there will be the potential for a lake effect band to form. Uncertainties in the flow direction precludes a more confident forecast, so I’m sticking with the same #s for the Cottonwoods. Just keep in mind that totals there could easily end up in the upper range or even higher if a lake band forms and parks itself over the Cottonwoods. Hopefully we’ll have some better ideas on this potential tomorrow.