December 4, 2017

MOUNTAIN WEATHER FORECAST

Time and Day: 0630 Monday

The Snapshot: Clearing and cold today.  Dry, clear and warmer weather will continue through the week.

The Science

Current Observations:
It is beginning to clear over the mountains this morning. The temperature is 240f on the lower mountain and 190f on the upper ridge.  The RH is 91% and the barometer is 1021mb and rising.  The winds are a bit gusty and out of the west.  

The Forecast:
High pressure has begun to build over the PNW and is expected to bring a dry and relatively warm weather for the remainder of the week. 

The feature of interest: With warm air advection occurring along the western slopes and cold air setting in the eastern basin, a temperature inversion will form.  This creates of few things for Stevens Pass.  East/west pressure gradients along the Cascade crest will increase easterly winds.  Freezing levels to the east will be near 4000’ while the freezing levels west of the crest could peak near 9000’.   Some areas could see a low elevation cloud layer form or a best dense early morning fog.  Sunshine will be abundant in the high mountains.  


The Long Range:  The high pressure strengthens under strong southerly flow through the week.  This trend of warm, clear, dry weather is likely to continue through the upcoming weekend.     

24hr Precipitation ending at 4am:
Today 24hr water: 0 snow:0
Tomorrow’s 24hr water:  0 snow: 0

Trend and Timing:
No precipitation is expected for the next 7+ days.


24hr temperature ending at 4 am: 
Low: 22    High: 32
Freezing level: +- 4500’

Trend and Timing:   
Diurnal temperatures fluctuations will occur over the next few days with peak daytime temperatures reaching into the high 30’s tomorrow.

 
24hr Winds (mph) ending at 4 am:
Base: 0-5 W
Ridge Top: 5-10 W

Trend and Timing:
Westerly flow will diminish today and shift easterly tomorrow.



jM

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