Weekend Forecast, 2/25/2017 – 2/26/2017:
From Dan Tackett, Sugar Bowl National Ski Patrol Meteorologist Extraordinaire
Updated Thursday, February 23rd, 10:50 am
Occasional snow last Saturday picked up the pace on Sunday, then heavier Sunday night. The most worrisome part of last week’s forecast was the risk of rain on the slopes for Monday. Although a sub-tropical air mass was scheduled to raise snow levels to 7000 feet or possibly more, it was overcome by heavy precipitation rates that pushed snow levels a little lower and the delay of extremely high winds that tend to carry the warmer air mass. With the sub-tropical air mass losing out, it was heavy snow for the entire event at all resort elevations. Snow continued overnight as cooler air begin to filter in, but that’s when the winds became extreme. Around midnight, three separate gusts on the top of Squaw Valley/Alpine Meadows exceeded 190 mph, with the top gust at 199 mph. Those are the highest velocities I can recall ever seeing. I’m not 100% sure about the accuracy since I don’t know if the wind measuring devices are calibrated for those type of numbers. Either way, those type of winds make many hurricanes appear tame.
While most of Northern California was beginning to clear on Tuesday, a low pressure trough and onshore moisture kept the storm going through the day. Although winds weren’t as extreme as the previous night, they were still gusting over 100 mph. Conditions didn’t settle down until the pre-dawn hours of Wednesday. The Monday through Tuesday totals ranged from 2-4 feet. Snow showers on Wednesday afternoon added another couple of inches, then a burst of overnight snow added yet another 5 inches.
Thursday dawned with most snow showers having shifted to the south. With the atmosphere remaining slightly unstable, snow showers will again pop up, mostly in the afternoon or evening. With moisture becoming a little more scarce, additional accumulations are expected to be only an inch or 2. Temperatures have chilled to some of the coolest conditions of February, with highs mostly in the upper teens to mid 20s. Winds are thankfully relatively light.
Conditions are expected to be fairly quiet on Friday. An area of low pressure is expected to approach from the Gulf of Alaska Friday night. The track of the system is keeping most of the moisture and dynamics off the coast, but enough energy will get snow showers going again overnight. Any accumulations by sunrise Saturday will be very light. Friday morning temperatures are expected all the way down into the single digits to low teens.
Scattered snow showers are expected on Saturday as the low pressure center cruises by to our west. Any daytime accumulations again will be very light, maybe up to another inch or 2. Temperatures continue on the cool side with highs in the upper teens to mid 20s.
A second area of low pressure approaches in the pre-dawn hours of Sunday. A couple of days ago, the models had this system merging with sub-tropical moisture and producing heavy accumulations. Today’s models are leaving out the sub-tropical moisture for Northern California. Snow and snow showers are still expected, but total accumulations will be in the moderate category. Daytime accumulations are now expected in the 4-8 inch range, with an additional 3-6 inches overnight. It will be breezy at times, but not the type of wind speeds we saw last Sunday and Monday.
Snow showers decrease on Monday as the system begins to exit. Partial clearing on Tuesday will lead to mostly sunny conditions on Wednesday as a high pressure ridge takes up residence in Northern California. At this time, there could be an extended break in our season of frequent storm cycles. Those storm cycles have created an unbelievable snowpack of many, many feet. It’s hard to believe that only 2 years ago during the very same weekend, only 6 inches of snow covered the lower slopes. The extremes of the Sierra are in full display.
Sugar Bowl Snow Depths as of Thursday, February 23rd:
Station A near the base: 147 inches. Last year at this time: 49 inches.
Station B mid-mountain: 240 inches. Last year at this time: 126 inches.
Current Truckee River Drainage Snowpack Water Equivalent to Normal: 213%
Holiday Weekend forecast for 2/25/2017-2/26/2017:
Mostly cloudy on Saturday with scattered snow showers. Daytime accumulations of up to 2 inches. Lows in the teens, highs in the upper teens to mid 20s. Southwest ridge winds to 30 mph, light elsewhere.
Mostly cloudy on Sunday with snow and snow showers. Daytime accumulations in the 4-8 inch range. Lows in the teens, highs in the upper teens to mid 20s. Southwest winds to 15 mph, to 40 mph on the ridges with higher gusts.
Weekend Travel Weather:
Minimal snow related road problems are expected on Friday. Light snow may create slippery conditions on Saturday, especially with snow levels down to around 1500 feet. Steadier snow on Sunday will likely lead to chain controls.
Snow showers decrease Monday, a dry period begins sometime on Tuesday.
Have a Great Weekend.