CLIMATE ATLAS OF
WESTERN WASHINGTON

This book is the result of 15 years research and accumulation of various climate features associated with Western Washington. The first 30 pages are basically a revised version of Western Washington Climate, completed in 1986. I am proud to have added much new and relatively exciting material which I have done independent research on, such as "Tree Ring Response to Climate in the San Juan Islands", "Prehistoric Climate Record of the Pacific Northwest", and Atmospheric Circulation Patterns. One can compute a current wind model from the weather radio, and compare it with the modeled wind direction maps (see Miscellaneous section). Studies were also done to compare the phase of the moon and solar cycles with our local climate, and surprising correlations were discovered.

SEASONAL CLIMATE MAPS:

INCLUDING: Annual Precipitation, Temperature, Sea Level Pressure, Prevailing Wind Direction, Wind Speed, and Upper Air Data.

OROGRAPHIC INDUCED
WIND AND PRECIPITATION PATTERNS

The Olympic, Vancouver Island, and cascade Mountains, play a dominant role in directing the prevailing winds, causing con-vergence zones and rainshadows, that are well known to the local residents. The following maps indicate surface wind directions and precipitation patterns correlated to the wind direction at about 10,000 feet (7,000 mbar level), where mountains have little effect upon atmospheric flow over Western Washington.

WIND PATTERNS

PRECIPITATION PATTERNS

Localized surface precipitation is governed by orographic features, and can be correlated to the wind direction at 10,000 feet. The following model maps were computed using 15 ideal days for each wind direction, and consisted of the following variables: wind direction consistent for the duration of one day, moderate winds, sufficient precipitation, and cloud height bases averaging 1500 to 2500 feet. With sufficient amounts of precipitation, station amounts could be standardized for each day, and thus, increased the data resolution.

The average amount of Western Washington precipitation for all directions has been standardized so that each map can be easily cross correlated with another, and thus provides a quick reference of orographic influence. The NE Olympic "rainshadow" observed cloud density (50 observations: 2100, 240°, and 270°) follows a general migration from north of Port Discovery (210°) to south of the San Juan Islands (270°) before merging with the Vancouver Island rainshadow.

HISTORIC RECORD
OF AVERAGE WESTERN WASHINGTON
TEMPERATURE AND PRECIPITATION

TREE RING RESPONSE TO CLIMATE IN THE SAN JUAN ISLANDS

PREHISTORIC CLIMATE RECORD OF THE PACIFIC NORTHWEST

Prehistoric Record of Climate in the Pacific Northwest, the past 6,000 years, derived from pollen records of a dozen lake records in the Pacific Northwest, including lake sedimentation rates per century.

western washington precipitation monthly average and individual stations
western washington temperature daily average 1931-2001
western washington temperature daily station averages
Western Washington Temperature Daily Amplitudes (Hi to Low) 1931-2001
Western Washington Temperature Average (10 Sites) Maximum and Minimum

CORRELATION OF TEMPERATURE TO CLOUDINESS
Using the temperature Hi minus low as an index of cloudiness, this index is correlated to temperature, and shows that summer cycles are warm/clear vs cool/cloudy and winters are warm and cloudy vs cold and clear

(WESTERN WASHINGTON 10 AVG STATIONS 1931-2001)
MONTH OF YEAR     1    2    3    4    5    6    7    8    9    10   11   12
CORRELATION       -.24 -.03 .15  .49  .50  .54  .56  .53  .38  .01  -.20 -.30



COMPARISON OF BAROMETRIC PRESSURE AND CLOUDINESS (USING AMPLITUDE INDEX)
Barometric Pressure consistently preceeds sky cover by an average of 1.2 days, and the correlation of cloudiness (any lag) compared to pressure is strongest in summer and weakest in winter.  (Highest pressure 1.2 days before clearest skies, and lowest pressure 1.2 days before cloudiest skies).

(LYNDEN, WASHINGTON 6 YEARS 2002-2007)
MONTH OF YEAR     1    2    3    4    5    6    7    8    9    10   11   12
CORRELATION       0.29 0.35 0.32 0.35 0.45 0.59 0.42 0.44 0.38 0.33 0.21 0.10     avg  .375 correlation
LAG Amp from PR   1.4  1.8  0.5  1.0  1.1  1.3  1.2  1.2  1.4  1.4  0.6  0.8      avg 1.17 days 

NORTHERN HEMISPHERE SEASONAL CLIMATE MAPS

RECURRENT LARGE-SCALE
ATMOSPHERIC CIRCULATION PATTERNS

BASIC THEORY OF
HOW CLIMATE CYCLES WORK*

The ability to forecast climate has intrigued man for several thousand years. It has been only in the past several decades that we have accumulated a vast understanding of how and why climate varies. It is now apparent that climate does not vary in some disorganized and random behavior, but varies, for the most part, in a very systematically arranged and cyclic pattern. These cycles are associated with variations in the average temperature, precipitation (and cloudiness), wind and atmospheric pressure. They can be cycles a few days to a few millennia in length.

With an understanding of four basic concepts, one can rather easily observe any cycle in climate and roughly forecast when the next maximum or minimum (temperature, precipitation, etc.) should occur:

1) Climate variation is primarily composed of periodic oscillations (cycles), half cycles, and half cycles of half cyces, etc. Observed climate oscillations are found at periods of about 27-28, 13 to 15, and 6 to7 days, and long term oscillations occur at about (5600 years), 2800, 1400, 700, 350, (175), 88, (44), 22, 11, 5.6, 2.8, 1.4, 0.7, and (0.35) years. The annual cycle has a semi-annual component in certain climate features. Periodic oscillations apparently not associated with half cycles, are found at about 2.2 years, and 45 (30-60) days. It would be difficult to use the first basic concept without an understanding of the next (second) basic concept.

2) Most all cycles vary in period length and amplitude according to the phase of longer term cycles. A general rule which can be applied to most Pacific NW Climate oscillations is that the period length and amplitude of a cycle (especially temperature) will usually be longer and larger during the warm phase of longer period cycles, and shorter and smaller during the cool phase of longer period cycles. The simple variation of these cycles greatly increases the probability of identifying a cycle. For instance, since the 4-8 day amplitude and period length follows an about 13-15 day rhythm, this makes three ways to identify the two week oscillation. While it is relatively easy to observe climate oscillations, forecasting them is somewhat tricky, and limits relatively accurate forecasts to about one to two cycles in advance.

3) The third basic concept of climate oscillations describes the general nature of atmospheric flow: Short term cycles (less than about 2 months) are generally traveling waves in the atmosphere that propagate eastward (flow with the westerlies), whereas longer term cycles generally are geographically fixed fluctuations(remain stationary). In the Pacific Northwest, these longer term cycles are predominantly associated with mass increases or decreases in Pacific Pressure, with a central point of tendency near the Aleutian Low during winter months, and Pacific High Pressure in summer. Lower Pacific Pressure brings in a southwesterly flow of warm air to our area, whereas higher Pacific Pressure brings in a northwesterly flow of cool air. Short term cycles originate near the mid Pacific to Western Pacific at about the midlatitudes in response to upper air disturbances (two and four week) and tropospheric heating displacement (one week).

4) Most all of climate cycles, from a few days to several millennia in length can be attributed to, or triggered by, solar variations. Lunar variations can account for 18.6 year, and one-two-four week cycles. Solar variations come in two basic forms: Solar radiation and magnetic field variations. While Solar radiation variations disrupt the earth's ozone layer, solar magnetic field variations disrupt the particles of earth's magnetic field. Particle disturbances in the middle and upper atmosphere can be transferred to earth's surface via wave coupling inthe atmosphere. Important solar variations to remember are the 27 day rotation period, the 13.5 day (half) cycle, the 11 year and 88 year sunspot cycles.

FOR A BETTER UNDERSTANDING ABOUT THE SUN, AND HOW IT AFFECT OUR EARTH:
SOLAR BASICS
SOLAR VARIATIONS
EARTH SUN RELATIONSHIPS
SOLAR EFFECTS UPON CLIMATE

The earth itself can produce its own half cycles. With solar (or lunar) forcing, a single wave is formed over the earth. In turn, this wave can produce two separate waves, either because of the two separate continents and oceans, or blocking at the extrema of cycles originating from equatorial/polar heat displacement.

AMPLITUDE AND PERIOD LENGTH MODULATION

The 45 to 11 year cycles show a distinct 50% reduction in amplitude (intensity) with increasing longer periods. For example, the modeled precipitation amplitude is as follows: 45 day67±33%, 0.7 year33±l6%, QBO17±8%, 5-6 year8±4%, and 11 year=4±2%. The two week cycle is about 90±40%. Temperature is less discernible: 45 day (2.48°F), 0.7 year (0.9°), QB0 (0.6°), 5-6 year (1.0°), and 11 year (0.6°).

Cycle period lengths are not directly in phase, and after lag has been removed, have a standard deviation (correlated value) or ±18% of the period length. This is logical, in that it infers a model value of 16.67% and a 1/3 period warm, 1/3 period cold, and 1/3 period transition (1.0 period divided by 3=33.3%, or amplitude ±16.7% or period). It is noted that at about 5-6 years the amplitude approaches ±1.0 year.
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*Based on original manuscript 1987 "Forecasting Pacific Northwest Climate: The Theory Behind How Climate Cycles Work" by Gary J. Morris

MISCELLANEOUS

Modeled Regional Wind Patterns

Modeled 280 Wind Pattern for Northwest Washington

Click on image to enlarge

FRASER WIND OUTBREAK OVER WESTERN WHATCOM COUNTY

Quite often during the winter, Arctic Air blows from the NE, through the Fraser River Canyon, and over much of Western Whatcom County. The pattern expressed here persisted for a period of several weeks during January and February 1992. There is clearly a "wind shadow" that develops below the Sumas Mountain wind boundary, and produces calm winds on a NE to SW gradient. Also, there is a precipitation boundary zone, about 2 miles in width (quite noticeable on the Guide, between Bakerview and Smith Road), forming: (1) very cold, dry air North of the Boundary, and cool, moist (snow) to the south; or (2) cold, moisture-mixed Fraser Air (snow) to the North, and mild-wet (rain) to the south of the boundary.

Click on image to enlarge

BIBLIOGRAPHY

All images are at about 25 percent of clarity, in order for quick download on the internet for older computers. To obtain full file size of pictures, EMAIL the author.

REVISIONS AS OF SEPTEMBER 1996 WESTERN WASHINGTON CLIMATE
[EMAIL me at garymorris93@hotmail.com]