Winds and Weather Flashcards
pass the test
USCG Weather Forecasts are broadcast on What Channel?
VHF 22A
NOAA Weather broadcasts on what channel?
126.55mhz Seattle 162.47mhz Olympia
Nationa; Weather Service Forecast Weather how?
Weather fax
Marine Weather forecasts are transmitted?
4 hours daily with updates every 2-3 hours
Puget Sounds climate is mild because?
Prevailing westerlies bring in mild moist marine air from the pacific ocean
The average annual rainfall in puget sound is?
38 inches
The steady influx of marine air results in?
mild winters and cool summers
Daily temperature range is described as?
small and short duration
How many thunderstorms are averaged annually in Puget Sound?
8 Thunderstorms
What months are the winds strongest at the entrance to the Strait of Juan de Fuca?
October thru March
As low pressure systems approach the coast, what does the wind do?
strengthens and backs to the SE quadrant
As storms pass the coast, what does the wind do?
Wind veers to the SW or NW
Gales usually last ____ days with duration between storms ___________ days?
less then one day, 1-5 day duration
What are the two wind seasons?
Winter- October thru March
Summer- April thru September
From October thru March, winds blow at the entrance mostly from where?
SE-SW with gales 4-6 days per month
Which winds raise dangerous and confused seas off cape flattery?
SE and are consistently the strongest
What makes Vancouver Is a dangerous lee shore betwween Cape Cook and Port San Juan?
Strong winds from the South
Winds near the entrance to the Straits have been recorded at what strength?
65kts with gusts to 90?
In the straits, strong winds have been recorded at what speeds?
50kt winds with gusts near 80 have been reported
Where is it safer when the wind blows from the South?
Usually inside the straits when off-shore
In the summer, what is the predominant wind direction?
SW thru NW around subtropical highs
In the summer, what influences the wind in the late afternoon?
The sea breeze can result in winds up to 30kts
What winds are the most frequent in the Straits of Juan de Fuca in the Summer?
SW thru West
In the winter (Oct-Mar), what are the most frequent winds in the strait of Georgia?
SE’ly are most common
Despite being sheltered by the mountains and Vancouver island from the sea, how often are gales in the winter in the strait of Georgia?
3-4 times per month
What is a Suquamish Wind?
A sudden wind that occurs in most major inlets of the strait of Georgia in the winter months and can result in winds up to 50kts
How can Puget Sound be described with regards to weather?
Open to the North and South and Protected to the East and West by Mountains
Where are the winds from in Puget Sound in the Winter (Sept-Mar)?
Mainly from the SE-SW
Where are the winds from in Puget Sound in the late Spring and Summer?
North thru NW
What is responsible for the mainly S’ly flow in Puget Sound?
Lows moving thru or Near Puget Sound
What best describes the strength of winds in Seattle?
Sustained Winds of 56kts gusts to 60 have been recorded with winds strongest in winter and early spring.
What is the most common type of fog in The straits
sea fog
When is sea fog the worst in the straits?
July to October
When is land fog encountered?
The winter Months
Where is fog the most frequent in the straits?
Western end
How many days annually is visibility reduced on average in the straits of Juan de Fuca?
55 days on the west end, 35 days on the east end
Fog is carried by a sea breeze and usually penetrates further on which shore of the Straits of Juan de Fuca?
Southern Shore
Where is fog less likely to reach in the straits of Juan de Fuca?
Victoria
`Often when thick fog prevails in the straits of Juan de Fuca….
Skies are clear north of Race Rocks
Which type of fog more effects the strait of Georgia?
Land fog more then sea fog
How does land fog form?
Land Fog forms on cool, clear nights with light winds and usually dissipates by early afternoon.
How many days per year does fog cause visibility problems in Puget Sound?
25-40 days annually on average
When is fog most likely to hinder Navigation on Puget Sound?
Autumn and again in Jan/Feb
In Admiralty Inlet, fog limits Navigation to less then .5nm how often?
4-8 days per month during the foggy season
Where is fog less likely to occur in Puget Sound?
Off Point Wells and Three Tree Point
In Seattle, visibility falls below .5nm how often?
3-6 days per month in the foggy season
A significant Navigational Hazard: fog
Land and Sea fog combining at the western straits
A significant Navigational Hazard: Wind/Seas
SE wind meeting heavy SW Swell makes a dangerously confused sea at the entrance to Juan de Fuca
A significant Navigational Hazard: rain
Heavy rains at the entrance from December thru March often reduce visibility below .25 miles
