Stevens Pass
Mountain Weather Forecast
Day and Time: Monday 0630
Current Observations:
24hr Precipitation: 0
Temperature profile: 29 base, 23 ridge
Pass level winds: light and out of the east
Barometer: 1026mbs steady
Sky: clear
Radar: clear
The Forecast: More
sunshine today but with cooler temperatures.
The same but with some added high level clouds can be expected tomorrow.
Long
Range: Snow for
Friday and Saturday? Possibly.
The Science:
Easterly flow, that formed overnight,
has begun to usher in cooler air from the interior west. This change is due to
the center of the high pressure drifting east toward the intermountain west and
a weak cut-off low forming along the Oregon Washington border. Disturbances trying to make their way east
will still be blocked or split by this feature through early Thurssday.
Thursday through Saturday,
the northern jet stream makes a visit to the Gulf of Alaska. This will provide
a period of NW flow with a few winter storms forming within the jet.
Good confidence is still a
day or two out, so for now, we can anticipate some potential measurable snow
heading into the weekend. Stay tuned.
Values from 4am today through
4am tomorrow.
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Precipitation:
Today 24hr
water: 0 snow: 0
Tomorrow’s 24hr
water: 0 snow: 0
Trend and Timing:
0
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Temperature:
Low: 24 High: 32
Freezing level: +-2500
Trend and Timing:
Freezing levels will drop to +- 2500’
today. Daytime temps will recover to
near freezing with the aid of the sun.
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Winds
Base: 5-10 E
Ridge Top: 5-15 E
Trend and Timing:
Gusty easterly winds will persist
through the next 24-36hrs.
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Glossary of PNW Weather Terms:
Storm Water Equivalent (SWE)…. how much water is in the
snow or rain
Orographic lift…. an airmass that is lifted as it moves up
and over higher terrain. This promotes cloud development, and enhances
precipitation.
Dirty Ridge…. a weak, unorganized high pressure ridge.
Advection…. the transfer of heat by the flow of
fluid. For the PNW, this is usually from warm moist air entering the
region from the south.
Flow…. wind direction. In meteorology, the wind
direction is always noted where the wind is coming from. East flow
is wind coming from the east; SW is from the south west…
The Inter-mountain West….. the region between the Rock
Mountains and the Cascade Mountain ranges.
Mainly Idaho and Western Montana.
Puget Sound Convergence Zone….. This is formed when large
scale westerly flow splits around the Olympic Mountains and then converges over
Puget Sound. The flow then accelerates
up the river valley’s enhancing the orographic effect at the Passes.
Occluded Front…..The boundary that separates the cold air
mass behind a cold front and the warm air associated with a warm front. When
the cold front overtakes the warm front it occludes.
High/Low Pressure…. High pressure is associated with
sinking air that rotates clockwise. High pressure often results in dry and
clear weather. Low pressure is rising
air that rotates counter clockwise and results in condensation, cloud formation
and precipitation.
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