MOUNTAIN WEATHER FORECAST

Time and Day: 1130 Thursday

The Snapshot:  The current radar shows the leading edge of the approaching storm just entering Puget Sound.  Snow should arrive early this afternoon and continue through the night.  With luck, we should see around + 6” of snow by noon tomorrow.

The Science: The warm inversion layer will continue to override the cold air trapped in the eastern valley’s today.  A weak warm front followed by a cold front will produce snow this afternoon with light snow showers continuing tomorrow.  The precipitation will taper off tomorrow night as a weak high pressure ridge develops.   Saturday will be mostly dry with sun breaks.

4-7day Long Range:  Another weak system arrives on Sunday with a similar outcome as tonight’s storm.  A large warm high pressure system develops off the PNW coast next week.  This will likely create NW flow over the PNW with weak disturbances passing through from time to time.  Freezing levels will remain at or just above 4000’ through most of next week.  

 

Precipitation:   Water by 4am = .25-.5 Snow equivalent = 4-6”   Total inches of water by noon tomorrow = .5 -.75 Total inches of snow by noon tomorrow = 5-8’   Trends and Timing:   Snow will begin to arrive around noon today.  Light to moderate snow will turn to showers tomorrow afternoon and taper off tomorrow night.

Base Temp and Freezing levels:                                        Low: 30    High: 34 Freezing level: 4000’        4500’   Trend and Timing:   The large warm air mass over the western portion of the state will continue to push the freezing  levels up in the mountains.  Freezing levels will fluctuate between 4000’ and 5000’ through the weekend.

Winds (mph)   Base: 0-5 E shifting SW Ridge Top: 5-10 SW shifting W   Trend and Timing:   Winds will shift westerly in the wake of the front later tonight. Westerly flow will increase tomorrow but should be much of factor.