000
WWUS86 KSEW 112134
SABNW 
MOUNTAIN WEATHER FORECAST FOR THE OLYMPICS WASHINGTON CASCADES 
AND MT HOOD AREA
NORTHWEST WEATHER AND AVALANCHE CENTER SEATTLE WASHINGTON
130 PM PST WED FEB 11 2009

NWAC Program administered by:
USDA-Forest Service
with cooperative funding and support from:
Washington State Department of Transportation
National Weather Service
National Park Service
Washington State Parks and Recreation Commission
Pacific Northwest Ski Area Association
Friends of the Avalanche Center
and other private organizations.

This forecast is prepared primarily for federal, state and 
private snow safety programs in Washington and Northern 
Oregon.

WAZ513-518-519-019-042-501-502-ORZ011-121700-

&&

WEATHER SYNOPSIS FOR WEDNESDAY AND THURSDAY
A northwest flow over the northeast Pacific Ocean should 
maintain a storm track that mostly misses the Northwest the 
next few days. A series of weak low pressure system should 
move southeast over the Northwest coastal waters to the 
Oregon California border area.

The first weakening low moved past on Tuesday. A weak front 
moved out of this low and across the Northwest. This caused 
some moderate crest level winds and snowfall. NWAC weather 
stations near and west of the crest received about 3-10 
inches of low density snowfall with the most at Paradise and 
Mt Hood.

The first low is moving into the Oregon California border 
area on Wednesday. However some moisture circulating around 
the low is over eastern Washington and causing some lower 
clouds from about Snoqualmie to Mt Hood. But a weak ridge 
and weak surface high pressure should move over the 
Northwest most of Wednesday evening and Thursday morning. 
This should cause light crest level winds, decreasing clouds 
and a slight rise in freezing levels in the Olympics and 
Cascades.

A second weak low should follow the storm track and move 
southeast over the Northwest coastal waters Thursday 
afternoon and night. Flow over the Northwest is indicated to 
remain weak but the low may spread some moisture mainly to 
the Mt Hood area and further south Thursday night.
&&

WEATHER FORECAST FOR WEDNESDAY AND THURSDAY

*OLYMPICS-
Wednesday afternoon: Mostly sunny.
Wednesday night: Mostly clear.
Thursday morning: Increasing high clouds.
Thursday afternoon and night: Mostly cloudy with chance 
of light snow.

*WASHINGTON CASCADES NEAR AND WEST OF THE CREST- 
*CASCADE PASSES INCLUDING STEVENS, SNOQUALMIE AND WHITE 
PASSES-
Wednesday afternoon: Mostly sunny except some clouds 
below about 4-5000 feet at Snoqualmie.
Wednesday night: Mostly clear except some lower clouds 
Snoqualmie.
Thursday morning: Increasing high clouds.
Thursday afternoon and night: Mostly cloudy with chance 
of light snow mainly south part.

*EAST SLOPES WASHINGTON CASCADES-
Wednesday afternoon: Mostly sunny except areas low clouds 
below about 4-5000 feet.
Wednesday night: Mostly clear except local low clouds 
below about 4-5000 feet.
Thursday: Increasing high clouds.
Thursday night: Mostly cloudy with chance of light snow 
mainly south part.

*MT HOOD AREA-
Wednesday afternoon: Partly cloudy.
Wednesday night: Mostly clear.
Thursday morning: Increasing high clouds.
Thursday afternoon and night: Increasing light snow.
&&

SNOW LEVELS-CASCADE MTNS
1000 ft N to S Wed morn
FREEZING LEVELS
2500 ft N, 3500 ft S Wed aft
Lowering Wed night
1000 ft N to S Thu morn
SNOW LEVELS
2000 ft N to S Thu aft
Lowering Thu night

SNOW LEVEL-OLYMPIC MTNS
1000 ft Wed morn
FREEZING LEVELS
3000 ft Wed aft
Lowering Wed night
1000 ft Thu morn
SNOW LEVELS
2000 ft Thu aft
Lowering Thu 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
                    THU     FRI

*HURRICANE RIDGE0     LT .10

*MT BAKER       0     LT .10
*WASHINGTON PASS0     LT .10
*STEVENS PASS   0     LT .10
*SNOQUALMIE PASS0     LT .10
*MISSION RIDGE  0     LT .10
*CRYSTAL MTN    0     LT .10
*PARADISE       0     LT .10
*WHITE PASS     0     LT .10
*MT HOOD        LT .10     .25

&&

WINDS IN MILES PER HOUR (MPH)

*CASCADE PASS LEVEL WINDS
E 5-10 Wed aft
Light variable Wed night to Thu morn
E 5-10 Thu aft and eve

*FREE WINDS AT 5000 FT
E 5-10 Wed aft
Light variable Wed night
SW 5-10 Thu morn
SW 5-15 Thu aft and eve

*FREE WINDS AT 9000 FT
E-NE 5-10 Wed aft
NW 10-15 Wed night
W 10-15 Thu morn
SW 1015 Thu aft and eve
&&

EXTENDED WEATHER SYNOPSIS FOR FRIDAY THROUGH SUNDAY
The second weak low should move into the Oregon California 
border area on Friday. Higher surface pressure should begin 
to build over Canada. Weak flow should be seen over the 
Northwest. This should cause partly or mostly cloudy weather 
over the Olympics and north Cascades and maintain some light 
snow showers over the south Cascades and mainly the Mt Hood 
area.

Yet a third weak low is indicated by the US GFS model to 
follow the storm track southeast over the Northwest coastal 
waters on Saturday and Sunday. This system is indicated to 
be a bit further offshore. Weak flow should continue over 
the Northwest. The surface high pressure over Canada and the 
offshore low should also cause offshore surface flow. This 
should limit the threat of light snow to the south Cascades 
and Mt Hood area Saturday and Sunday.

EXTENDED FORECAST FOR FRIDAY THROUGH SUNDAY
Friday and Friday night: Partly or mostly cloudy Olympics 
and north Cascades and light snow showers ending south 
Cascades.
Saturday and Saturday night: Partly cloudy with slight 
chance of light snow showers.
Sunday and Sunday night: Partly or mostly cloudy north and 
cloudy south with chance of light snow showers mainly south 
part.
 
*SNOW LEVELS
1-2000 ft N to S Fri to Sun lowest morning hours and 
highest afternoon hours.

NWAC weather data and forecasts are also available by calling 
206-526-6677 for Washington, 503-808-2400 for the Mt Hood 
area, or by visiting our Web site at www.nwac.us.

Ferber/Northwest Weather and Avalanche Center

$$