February 8, 2017

MOUNTAIN WEATHER FORECAST

Time and Day: 0600 Wednesday

The Snapshot:  A winter storm warning is in effect for the Cascades Mountains with heavy snow tonight changing to rain tomorrow and back to snow on Friday.   

The Science:  The leading edge of the approaching storm is just south of Olympia as of 5 am this morning, and is expected to reach Stevens Pass in a few hours or so.  This storm has impressive water content values with storm totals exceeding 3” or even 4”.  

Heavy snow will begin the show with a foot or more likely through the night, snow changes to heavy rain as freezing levels rise to +5000’ tomorrow.  A cold front enters the scene late tomorrow night which should produce some nice snow on Friday.   

Yes, there is a chance that the east flow will hold out and minimize the rain potential.  However, when water contents are this high, the atmosphere is pretty warm (8000’ freezing levels over Seattle) so it will be a tough fight for our east flow friend. 

 The Long Range:   Snow showers will persist into Saturday with strong high pressure moving into place on Sunday.  A dry, clear and warm airmass settles in early next week.

Precipitation Ending at 4am:
Today 24hr water = 1-2  Snow = 10-14
Tomorrow’s 24hr water = 1 snow = 2-6

Trend and Timing:
Heavy snow falling through the night with snow changing to rain after 4am tomorrow morning.   


24hr temperature ending at 4 am tomorrow: 
Low:  18   High: 34
Freezing level: 1500’- 4500’

Trend and Timing:   
Surface temperatures will hold below freezing until early tomorrow morning.  Temperatures expected to peak near 360 f around noon tomorrow.

 
24hr Winds (mph) ending at 4 am tomorrow:
Base: 5-10 E   
Ridge Top:  5-10 E shifting SW and strengthening.

Trend and Timing:
Easterly winds hold steady through the night.  Southerly flow aloft takes over early tomorrow morning with strong SW winds likely.





jM

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