January 31, 2020
MOUNTAIN WEATHER FORECAST
Stevens Pass Mountain Weather
Forecast
Friday, January 31, 2020. 0730a
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Current Observations:
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24hr Precipitation: .98” swe, 1” snow
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Temperature profile: 38 base. 36 ridge
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Pass level winds: moderate,
WSW, ridge top gusts +20
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Barometer: 1016mb’s and holding
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Sky: overcast and
raining
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Radar: Heavy rain throughout
western Washington with the eastern basin fairly dry.
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The Forecast: Windy and rainy today
with temperatures peaking near 40f. Rain
switches to snow after 4am tomorrow with good snow accumulation expected during
the day.
The Science: The anticipated rain event is in full swing
with freezing levels well above 5000’.
The moist, warm SW flow will continue today with cooler temperatures
arriving tomorrow morning. Winds will be
a player today with models showing 5000’ winds +40 knots this afternoon and tonight.
Tomorrow’s game will begin with a strong cold
front swinging in to save the day. Cold
NW flow aloft will fill in behind the front with freezing levels falling to
4000’ by noon or so. Potential convergence zone with good
orographics will produce some measurable snow. With some luck, we could see a foot of snow on
the ground heading into Sunday.
Long Range. Remnant snow showers will linger into Sunday with
low freezing levels. Sunday and Monday
could shape up to be a great powder days.
More storms on the way for
Tuesday and beyond.
Confidence: Good.
Values from
4am today through 4am tomorrow.
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Precipitation:
Today
24hr
water: 1-1.25
snow: 0
Tomorrow’s
24hr
water: 1-1.25
snow: 10-14
Trend and
Timing:
Rain switches to snow on the upper mountain after 4am tomorrow morning.
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Temperature:
Low: 36 High: 42
Freezing
level: 7000’ – 5000’
Trend and
Timing:
Temperatures will remain well above freezing through the night. Freezing levels fall to 5000’ after 4am,
then reaching 4000’ by 10am or so.
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Winds
Base: 5-15
W gusty
Ridge
Top: 10-20 WSW gust +40 possible
Trend and
Timing:
Winds will be moderate to high throughout the day.
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January 30, 2020
MOUNTAIN WEATHER FORECAST
Stevens Pass Mountain Weather
Forecast
Thursday, January 30, 2020, 1000
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Current Observations:
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24hr Precipitation: .45 swe, 4” snow
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Temperature profile: 27base,
31 ridge
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Pass level winds:
light WSW
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Barometer: bumped
up to 1022mb’s
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Sky: broken
clouds
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Radar: dry conditions throughout the
state.
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The Forecast: Snow turning to rain
arrives late this afternoon with heavy rain and high winds expected through the
night. Windy and rainy conditions
continue all day tomorrow.
The Science: The current temperature inversion is the
indicator of the warm air streaming into the region from the southwest. A strong warm front will charge in tonight
with rising freezing levels and heavy precipitation expected. The moisture source is a long SW fetch strung
out well beyond Hawaii. A fairly
textbook pineapple express weather event.
The good news.
Cold unstable NW flow swoops in Saturday with some possible snow
accumulation on the tail end of this inpressive storm.
Long Range: The rain turns to snow on Saturday with 6-8”
possible heading into Sunday. Snow showers with falling temperatures are
expected on Sunday and Monday.
Forecast confidence: Good.
Values from
4am today through 4am tomorrow.
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Precipitation:
Today
24hr
water:
1-2” snow: 1-2
Tomorrow’s
24hr
water: 1-1.5
snow: 0
Trend and
Timing:
Snow will start sometime after 4pm and change to rain soon
thereafter. Rain is expected all day
tomorrow.
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Temperature:
Low: 32 High: 42
Freezing
level: 4500’ – 7000’
Trend and
Timing:
Freezing levels will rise tonight peaking near 7000’during the day tomorrow. Freezing levels are not expected to drop
back down until sometime on Saturday.
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Winds
Base: 0-5 e shifting WSW and strengthening
Ridge Top:
5-10 E shifting SW
Trend and
Timing:
The winds will shift WSW with the passing of the front later
today. A high wind advisory will go
into effect tonight and continue through morning hours.
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January 29, 2020
MOUNTAIN WEATHER FORECAST
Stevens Pass Mountain Weather
Forecast
Wednesday, January 29, 2020, 0800
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Current Observations:
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24hr Precipitation: .02swe, 0’ of snow thus far
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Temperature profile: 32 base, 30 ridge
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Pass level winds: light, easterly
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Barometer: 1017mb’s and falling
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Sky: OC and lightly
snowing
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Radar: heavy moisture heading into the moisture
with an embedded warm front attached.
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The Forecast: Heavy snow today with
some mixed rain possible below 4500’.
The moisture tapers off tonight with tomorrow being mostly dry. Rain arrives tomorrow night.
The Science: An approaching triple point frontal system,
holding a good batch of moisture, will bring heavy snow to the mountains today.
The leading warm front will spike
freezing levels to +-4500’ this afternoon. The trailing cold front will swing through
tonight, cutting off the moisture, thus this snow event will be relatively
short lived.
A weak high pressure ridge between storms will
bring dry weather with some partial clearing tonight and tomorrow.
The incoming rain event: Models are starting to align with the incoming
rain event starting tomorrow night. Strong
SW flow with warm air convection will push freezing levels to +7000’ by Friday
morning. There may some snow on the front
end and tail end of this storm but, for the most part, it will be full on rain.
Early Storm Water Equivalent (SWE) calculation are
2.5”- 4” between 10pm Thursday and 4am Saturday.
Long Range. The rain is expected to stop sometime early
Saturday morning with cold air arriving over the weekend. With some luck, we could see a little snow accumulation
Saturday morning as this storm exist the region.
Confidence: Good.
Values from
4am today through 4am tomorrow.
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Precipitation:
Today
24hr
water: .75
snow: 6-8
Tomorrow’s
24hr
water: .75-1
snow: trace
Trend and
Timing:
The snow will be the most intense this afternoon with drying beginning
after 7pm tonight. Little snow is
expected overnight.
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Temperature:
Low: 28 High: 34
Freezing
level: 4500’
Trend and
Timing:
Freezing levels will spike up to 4500’ today and then fall back to 4000’
tomorrow.
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Winds
Base: 0-5
E
Ridge
Top: 5-15 SWS gusty
Trend and
Timing:
Light east flow at the surface will switch SW overnight. Gusty ridge top winds will kick-in this
afternoon as the front passes, but they should be fairly short lived.
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January 28, 2020
MOUNTAIN WEATHER FORECAST
Stevens Pass Mountain Weather
Forecast
Tuesday, January 28, 2020, 1030
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Current Observations:
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24hr Precipitation: .65swe, 10” of snow
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Temperature profile: 30 base, 26 ridge
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Pass level winds: light easterly
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Barometer: holding steady at 1011,b’s
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Sky: overcast, light snow
falling
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Radar: A frontal boundary just passing
over the crest with wide spread precipitation over the western coastal
region.
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The Forecast:
Diminishing snow showers today with temperatures in the low 30’s. Tonight
will be quiet with moderate to heavy snow during the day tomorrow. Temperature will be consistently near
freezing.
Another, relatively short-lived punch of moisture arrives tomorrow with
4-6” of snow accumulation likely during the daylight hours.
The Science:
The low pressure trough that brought the snow
early this morning is expected to sag south today. The associated weak frontal band will keep
the light snow falling above 3500’ through the day. The moisture will diminish this afternoon as
the barometric pressure pushes up a few notches.
Friday and Saturday are looking very wet (rain)
with high freezing levels (6-7000’) Descriptive terms such as an atmospheric
river, and or pinnacle express are being thrown around in other forecast discussions.
More on that tomorrow.
Long Range.
Thursday will be relatively quiet with moderate to heavy rain and high
freezing levels expected Friday and Saturday. A cold and dry weather pattern
develops during the first full week of February.
Confidence: Good.
Values from
4am today through 4am tomorrow.
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Precipitation:
Today
24hr
water:
.25 snow: 2-4
Tomorrow’s
24hr
water: .75
snow: 4-6
Trend and
Timing:
Light snow today will diminish tonight with the next push of moisture
arriving mid-morning tomorrow.
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Temperature:
Low: 30 High: 34
Freezing
level: +-4500’
Trend and
Timing:
Freezing levels will remain around 4500’ through the night.
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Winds
Base: 0-5
W
Ridge
Top: 0-10 WSW
Trend and
Timing:
The wind will be light today and shifting westerly.
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January 27, 2020
MOUNTAIN WEATHER FORECAST
Stevens Pass Mountain Weather
Forecast
Date: Monday, January 27, 2020
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Current
Observations:
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24hr Precipitation: .5” SWE / 5” snow
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Temperature profile: 31 base / 27 mid mtn
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Pass level winds: Light-mod westerly
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Barometer: 1016 rising slowly
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Sky: Few clouds
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Radar: Spotty showers in the mountains with a convergence zone near Glacier
Peak
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The Forecast: Mostly dry and mild during daylight hours today, with
moderate to heavy snow overnight. Snow showers continuing Tuesday.
The Science: A quick moving trough made landfall
overnight and is currently east of the Cascade Crest. It brought a shot of 4”
of snow in a couple hours and slightly lowering freezing levels with some
colder air aloft. The most recent balloon sounding on the Olympic Peninsula had
the freezing level at 3200’, a welcome change from the past few days. A short
lived high pressure ridge is sweeping thru this morning, but won’t last long in
this progressive pattern. Most of the daylight hours Monday will be dry and
calm, however, the next low pressure system is rapidly approaching with the
warm front lifting from south to north this afternoon.
The warm front will spread moderate to heavy precipitation
across the Cascades after 10pm, reasonably high hourly precip rates can be
expected overnight before the trailing cold front swings thru and dials down
the intensity. Post frontal westerly flow will keep snow showers going most of
the day Tuesday.
Long Range:
Similar to the past 24 hours, a transitory ridge will move thru Wednesday
morning for a relatively dry start to the day before yet another low pressure
cell approaches, bringing moderate snow Wednesday night. A higher amplitude
ridge builds behind that for a mostly dry Thursday. Things may get sporty at
the end of the week with an atmospheric river event taking shape. Details on
exactly where the firehouse will be aimed are still coming together.
Confidence: Fair for snow amounts overnight. Poor for details on timing
middle to late in the week.
Values from
4am today through 4am tomorrow.
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Precipitation:
Today
24hr
water: .75-1.0
snow: 8-12”
Tomorrow’s
24hr
water: .5”
snow: 6-8”
Trend and
Timing:
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Temperature:
Low: 27 High:
32
Freezing
level: 3000-4000’
Trend and
Timing:
There could be some daytime warming, and a slight bump in freezing
levels with the warm front passage.
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Winds
Base: W-E-W
@ 5-10 with a few gusts
Ridge
Top: W-E-W @ 5-15
Trend and
Timing:
As the low approaches today, winds should shift to easterly thru the
Pass. After the low passes tonight they will shift back west as per usual.
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