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Karma: 4,686
Check it out we are going to get dumped on thursday.
WEATHER SYNOPSIS FOR TUESDAY AND WEDNESDAY
Following passage of a moderate to strong upper trough late
Monday that brought further moderate to heavy snow
accumulations to most higher elevation mountain locations, a
gradually and briefly decreasing west to northwesterly upper
flow produced decreasing showers Tuesday morning. Scattered
light showers should continue to diminish Tuesday afternoon
along with some partial clearing in the south-central
Cascades as orographic flow and low level moisture
decreases. However, ongoing moderate west to southwesterly
flow around a very deep upper low in the northern Gulf of
Alaska should continue to circulate substantial moisture
over much of south-central BC Tuesday, and as this moisture
sags slightly southward Tuesday afternoon, gradually
lowering clouds should reach the Olympics and northern
Washington Cascades later Tuesday afternoon. Sagging
moisture from the northern disturbances should combine with
incoming moisture from the next strong disturbance to
produce further increasing clouds and some light rain or
snow in the Olympics and northern Washington Cascades late
Tuesday afternoon and night. This should be accompanied by
gradually increasing ridgetop winds and slowly rising
freezing levels overnight.
By Wednesday morning, more significant effects from the next
strong weather system should become apparent as increasing
moderate rain or snow spreads southward along the
substantially rising freezing levels and further
strengthening winds. Heavy rain or snow, very strong winds
and briefly high freezing levels are expected late Wednesday
morning and afternoon before the front moves east of the
Cascades mid-late Wednesday afternoon. While some insulation
is expected from the warming aloft by a strengthening and
cool easterly surface flow through the Cascade passes late
Tuesday through early Wednesday afternoon, a wind shift to
briefly warmer westerly is likely mid-late Wednesday
afternoon, with snow briefly changing to rain below about 5
to 6000 feet in the central Cascades before cooler air
arrives Wednesday evening. As the front slowly exits the
region late Wednesday afternoon and evening, steady rain or
snow should be replaced by moderate to heavy showers.
Moderate orographic snowfall is likely in most areas near
and west of the Cascade crest and along the west slopes of
the Olympics behind the front Wednesday night as the upper
trough moves over the area.
&&
WEATHER FORECAST FOR TUESDAY AND WEDNESDAY
* OLYMPICS-
Mostly cloudy Tuesday afternoon with light showers
increasing late Tuesday afternoon. Occasional light rain
or snow increasing late Tuesday night. Light to moderate
rain or snow increasing and becoming moderate to heavy
Wednesday morning. Heavy rain or snow later Wednesday
morning through early Wednesday afternoon, especially
south and southwest slopes. Cooler with rain or snow
decreasing and becoming more showery mid-late Wednesday
afternoon. Moderate to heavy snow or snow showers
Wednesday night, heaviest west slopes.
* WASHINGTON CASCADES NEAR AND WEST OF THE CREST FROM MT
RAINIER NORTHWARD-
Partly cloudy extreme south Tuesday afternoon, but
mostly cloudy north and central with a chance of showers.
Occasional light rain or snow increasing north Tuesday
night with increasing clouds and occasional light snow
developing central Cascades late Tuesday night.
Increasing clouds and increasing light to moderate rain
or snow spreading southward early Wednesday. Moderate to
heavy rain or snow north and increasing light to moderate
rain or snow south later Wednesday morning. Periods of
heavy rain or snow mid-day and Wednesday afternoon,
decreasing and becoming more showery and mostly snow late
Wednesday afternoon and evening. Moderate to heavy snow
showers Wednesday night.
* WASHINGTON CASCADES NEAR AND WEST OF THE CREST SOUTH OF
MT RAINIER-
Partly cloudy Tuesday afternoon. Mostly cloudy Tuesday
night with occasional light rain or snow developing late
Tuesday night or early Wednesday. Increasing light to
moderate rain or snow spreading southward early
Wednesday. Light to moderate rain or snow increasing
later Wednesday morning becoming moderate to heavy mid-
day and Wednesday afternoon. Precipitation decreasing and
becoming more showery and mostly snow Wednesday evening.
Moderate to heavy snow showers Wednesday night.
* CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE
PASSES-
Mostly cloudy north and central Tuesday afternoon but
partly cloudy. Clouds lowering in the north late Tuesday
with a chance of showers. Occasional light snow
increasing north Tuesday night with increasing clouds and
occasional light snow developing central Cascades late
Tuesday night. Increasing clouds and increasing light to
moderate snow spreading southward early Wednesday.
Moderate to heavy snow north and increasing light to
moderate snow south later Wednesday morning. Periods of
heavy snow mid-day and early Wednesday afternoon becoming
rain or mixed rain and snow during the afternoon. Rain or
snow decreasing and becoming more showery and mostly snow
late Wednesday afternoon and evening. Moderate to heavy
snow showers Wednesday night.
* EAST SLOPES WASHINGTON CASCADES-
Partly cloudy south Tuesday afternoon, but increasing
clouds north with a chance of showers, mainly higher
terrain near the crest late Tuesday afternoon. Occasional
light snow increasing higher terrain in the north Tuesday
night with increasing clouds and occasional light snow or
snow showers developing central Cascades late Tuesday
night. Increasing clouds and increasing light to moderate
snow spreading southward early Wednesday. Moderate snow
north and increasing light to moderate snow south later
Wednesday morning. Moderate to briefly heavy snow mid-day
and early Wednesday afternoon becoming rain or mixed rain
and snow later Wednesday afternoon. Rain or snow
decreasing and becoming more showery and mostly snow late
Wednesday afternoon north and Wednesday evening south.
Moderate snow showers Wednesday night, mainly higher
terrain near the crest with light showers and partial
clearing lower elevations.
* MT HOOD AREA-
Partly cloudy Tuesday afternoon and evening. Occasional
light rain or snow developing late Tuesday night and
early Wednesday, increasing Wednesday morning and
becoming moderate later Wednesday morning. Moderate to
heavy rain or snow mid-day and Wednesday afternoon,
decreasing and becoming more showery and mostly snow
Wednesday evening. Moderate to heavy snow showers
Wednesday night.
&&
SNOW LEVELS-CASCADE MTNS
2500 ft N, 4500 ft S Tuesday night
3000 ft N, 6500 ft C, 7000 ft S Wednesday morning
6000 ft N, 7500 ft C, 8500 ft S mid-day
5500 ft N, 6000 ft C, 7500 ft S Wednesday afternoon
2000 ft N, 2500 ft C, 3500 ft S Wednesday night
1500 ft N, 2500 ft C, 3000 ft S late Wednesday night,
except snow levels lowering to near the surface Cascade
passes and east slopes late Tuesday, rising to near free
air levels mid-late Wednesday afternoon
SNOW LEVELS-OLYMPIC MTNS
3000 ft Tuesday afternoon and night
7500 ft Wednesday morning
7000 ft mid-day and early Wednesday afternoon
2500 ft mid-late Wednesday afternoon
1500 ft Wednesday night
Cascade Snow/Freezing Levels refer to the northern Washington Cascades
(N) through Mt Hood area (S). Central Washington Cascade snow levels
(typically near Snoqualmie Pass) are normally midway between indicated N
and S levels. Note that surface snow/freezing levels are common near
the passes during easterly pass flow and may result in multiple
snow/freezing levels.
&&
24 HOUR FORECAST OF PRECIPITATION IN INCHES OF WATER
EQUIVALENT ENDING AT 4AM
WED THU
* HURRICANE RIDGE .25 1-1.5
* MT BAKER .25 2-3
* WASHINGTON PASS LT .25 .75
* STEVENS PASS LT .25 1-1.5
* SNOQUALMIE PASS LT .25 1.5
* MISSION RIDGE LT .25 .75
* CRYSTAL MTN LT .10 2
* PARADISE LT .25 2
* WHITE PASS LT .10 1-1.5
* MT HOOD LT .10 1.5-2
[LT = less than]
&&
WINDS IN MILES PER HOUR (MPH)
* CASCADE PASS LEVEL WINDS
Variable 0-10 early Tuesday afternoon
E 0-10 later Tuesday afternoon
E 5-15 Tuesday night
E 10-20 Wednesday morning
E 15-25 later Wednesday morning and mid-day
E 10-15 early Wednesday afternoon
W 5-15 mid-late Wednesday afternoon
W 10-20 with higher gusts Wednesday night
* FREE WINDS AT 5000 FT
SW 10-20 Cascades, 15-30 Olympics Tuesday afternoon
SW 20-40 Cascades, 30-50 Olympics Tuesday night
S-SW 30-45 Cascades, 40-60 Olympics Wednesday morning
S-SW 40-60 Cascades, 50-70 Olympics mid-day and early
Wednesday afternoon
S-SW 30-45 Cascades, W 30-45 Olympics later Wednesday
afternoon
W 15-30 Wednesday night
* FREE WINDS AT 9000 FT
W-SW 15-30 N, 15-25 S Tuesday afternoon
SW 30-50 N and Olympics, 20-40 S Tuesday night
W-SW 40-60 N, 30-50 S early Wednesday morning
W-SW 60-80 N, 40-60 S later Wednesday morning
W-SW 60-80 N and S mid-day and Wednesday afternoon
W 25-40 N, 40-60 S Wednesday night
W 30-50 N and S early Thursday
&&
EXTENDED WEATHER SYNOPSIS FOR THURSDAY THROUGH SATURDAY
Behind the trough Wednesday night a weak to moderate west to
southwesterly flow should continue around the slightly
filling upper low to maintain a cool and intermittently
moist west to southwesterly flow over the region Thursday,
especially in the northern Washington Cascades and Olympics
which is most likely to be brushed by stronger disturbances
moving by mainly to the north. This should produce periods
of light to moderate snow in the north and generally lighter
snow or snow showers in the south along with some partial
clearing. Slightly stronger weather systems moving by to the
north should produce generally increasing snow or snow
showers in the north-central Washington Cascades and
Olympics late Thursday and early Friday and again later
Friday and early Saturday along with a lesser increase in
light to moderate showers in the south-central Washington
Cascades and Mt Hood area. The next strong weather system
now appear likely to begin affecting the region later
Saturday into Sunday, when moderate to heavy rain or snow,
strong winds and rising freezing levels are likely.
Fortunately, this warming looks rather short lived with a
return to a significantly cooler and still moist westerly
flow likely early next week.
EXTENDED FORECAST FOR THURSDAY THROUGH SATURDAY
Periods of light to moderate snow or snow showers north-
central Cascades and Olympics Thursday and Friday,
especially late Thursday through early Friday and again
later Friday into early Saturday. Otherwise partly to mostly
cloudy south with light to occasionally moderate showers,
mainly late Thursday through early Friday and again later
Friday into early Saturday. Gradual warming with increasing
winds and increasing light to moderate rain or snow
spreading southward late Saturday. Moderate rain or snow
north with increasing light to moderate rain or snow south
Saturday night into early Sunday.
* SNOW LEVELS
1500-3000 ft N, 2-4000 ft S Thursday
2-4000 ft N, 3-5000 ft S Friday
3-4500 ft N, 4-5000 ft S Saturday
3-5000 ft N and S late Saturday, rising on Sunday
