Los Angeles received the bulk of its rain in October 2004, and January, and February 2005. Such a pattern is more common for India during its three-month Monsoon.
Eight confirmed tornadoes in the Los Angeles basin also made for an active severe weather period.
* Monthly updates to San Juan Capistrano, CA weather may be of interest to readers.
In Orange County mountains the rainfall storm total during a four-day period of 7-10 January hit 20 inches, or closer to what Saddleback Mountain range typically records in 12 months. Almost anything goes in California; however, long-range forecast models did predict a wet-winter for the Southwestern United States and indicates that such a year could be more common in decades ahead.
The science of long-range weather prediction is an educated guess, but computer models provide information to use for practical purposes and planning rather than alarming residents.
In California, the largest economy in the United States, healthy rainfall and snow pack is the greatest challenge for the state as water demand exceeds what nature typically provides.
Figure 1 combines model data for rainfall
projection increases in California for the next 100 years.
Figure 2 combines model data for expected increases in temperatures in California for the next 100 years.
For the period 2010-2080, the future of water --indeed the state's most valuable resource-- is no sure bet. Canada's department of science for climate change models conflict with worst case drought predictions from the Union of Concerned Scientist, a California-based climate study organization. Canada actually offers California a big break in the long-range forecast, predicting rainfall totals of 150 percent above what has become "average" by year 2080. California governmental agencies are preparing for the drought model.
All long-range models conclude that California's temperatures will warm on the average of 3 to 6 degrees. Meaning, a current average temperature of 50 degrees (high and low temperatures averaged together) would warm to between 53 and 56 degrees. That in and of itself means little without folding out data into average high and low temperature plan at the regional level. For a city with an average high and low of 60 and 40, the temperature could change to 76 and 36 in a drier climate or 66 and 46 in a moist environment.
Statewide, the greatest increase in temperatures is expected during wintertime months. For sunshine lovers, the prediction of yearlong warm weather is good news -- for skiers however, the snow season across the Golden State maybe left to old photographs and memories. Warmer winters mean less snow, more rainfall, thus more rapid and dirty runoff, and little runoff in dry months.
To compare extreme models, we've calculated both possibilities using California's climate study group data, and Canada's research models along with some microclimate data known about California. For the graphics in this story, we've used Canada's data for rainfall estimates and both models for temperature.
California has numerous microclimates. Depending upon inland temperatures and cooler Pacific Ocean temperatures, the future of California's onshore flow hangs in the balance. Many of California's microclimates are in place due to existing climate trends and the availability or absence of the onshore flow. As these trends change, the microclimates will evolve accordingly. They could simply disappear. The Pacific Ocean currents are dependent upon salinity levels and temperature, as well as northern latitudinal ice melt. An increase in salinity levels and warmer water temperatures could lead to permanent waning of the onshore flow, warming coastline temperatures, and a increasing the monsoon influence in southern California during summer months.
When summertime monsoon flows infiltrate the desert regions, coastal areas from San Diego to Malibu experience less onshore flow and warmer temperatures due to cooler and cloudy weather in the desert regions. After two significant tropical waves in summer 2003 brought heavy July rains to the Sacramento Valley, the infamous onshore flow into the Bay Area subsided for the duration of this event as well. It is conceivable that even northern California summers may experience an increase of tropical weather, thus warming the coastline during these spells. What often dissipates tropical waves at the present time is cooler Pacific Ocean temperatures. As the Pacific water warms however, tropical waves are more likely to hold together and in fact maybe enhanced much in the way they are along the Eastern seaboard with warmer ocean temperatures.
On the other hand, the monsoon flow over Mexico, Arizona, and desert regions of California has its own set of dependencies. Both Arizona and New Mexico are in a cycle of less than robust monsoonal seasons, with only that of 2005 registering close to normal after a decade of weak monsoons. Should climate change cause the opposite effect, and decrease moisture influence from the tropics, the desert southwest's climate would be similar to that of the Persian Gulf and drop average rainfall totals to half of what they are today. Natural desert plant life would vanish and underground wells would run dry. The coastline of California's weather would be more alike that of Baja Mexico's dry, cool winters and long, hot dry summers.
Should California experience the worst case drought scenario, technology and resources could make ocean water ready for consumption at the current cost of inland water. Predictions for the Midwestern United States actually fair much worse that California at present time, and conclude that between years 2050-2100, the eastern front range of the Rocky Mountains may become the nation's largest desert region without means to secure consumable water.
If the worst case drought predictions prove correct for California --rainfall in Los Angeles (current 30-year average is 16 inches) will fall to an annual average of 12 inches by year 2050 and 9 inches by 2100-- or more like Las Vegas is today. San Francisco's average annual rainfall (currently 21 inches) would drop to 17 inches in 2050 and 13 inches in 2100. San Diego would drop from 11 inches to 7 inches.
Warming of the earth's surface creates more extreme weather events as the earth dissipates excess heat. As weather systems spawn and track East the influence upon California weather means: |
In viewing the past 30 years of average temperatures across California and comparing them to the previous block of 30 year cycles going back 90 years, there is no doubt that average temperatures have increased especially during winter months.
Predicting future temperatures is easier for Los Angeles and San Diego as they would more reflect those current temperatures along the Baja Mexico Peninsula. San Francisco's temperatures are more dependent upon the tug of air and water currents in the Pacific. But if the eastern Pacific waters warm as some models indicate, water temperatures of 70 degrees are possible in summertime along Northern California and 80 degrees in Southern California -- the onshore flow would diminish a great deal, and could result in coastal city temperature increases of as much as 15 degrees from today's averages. Warmer coastal cities like Santa Cruz would jump from 73 to 83, Long Beach from 81 to 90, and Del Mar from 78 to 87. Warmer ocean temperatures along California are also dependent upon a diminished NW-wind flow.
The average July-August high temperatures in Los Angeles could rise from 85 degrees today to 92 degrees in 2100, while San Francisco's average summertime high temperatures could rise from 71 to 77. San Diego could see a rise from 78 degrees to 86 degrees.
Western-facing beach cities, Monterey, Oxnard, Santa Monica and Oceanside will warm as well, although not as much as those coastal cities facing southern exposures.
If Canada's predictions are correct for rainfall, Los Angeles could see an average annual rainfall total of 23 inches, San Francisco would rise to 32 inches and San Diego would rise to 18 inches in 2050. Due to Los Angeles' and San Diego's proximity to warmer Pacific Ocean waters and the tropical monsoon zone, some of this rainfall could arrive in the form of two or three tropical waves each summer, such a change would be drastic to the current climate in southern California, especially if waters off the coast begin to support hurricane activity, which would pose great threats to residential and commercial property.
Northern California's increase in rainfall would primarily be due to more intense Pacific winter storms. For native plant life across all of California, Canada's prediction treats plant life very well. It is unknown whether or not the migration North of tropical waves would impact Mexico with widespread drought. Mexico is heavily dependent upon long periods of tropical rain showers in summertime for both residential consumption of water and for growing crops.
Averages are, after all, "average," one year's extreme weather averages out over time. For the past 50 years in Los Angeles the rainfall range is 6 inches to 38 inches. Using the new model of average, a dry year in Los Angeles could be 11 inches and a wet year closer to 50 inches. Fifty inches of rainfall in southern California could prove catastrophic without precautionary measures in place. Contrarily, on the dry models, three decades of rainfall less that 10 inches would wipe out all native species of plant life found in the region today. Live oaks, pine trees, and hillside shrubs would die and expose soil to erosion.
Additional and refined research could help long-range preparations for nation's most populous state. While there are no clear answers yet, preparation for climate change is a responsible action when time is on your side.