El Nino: Blessing or Curse?
By Benjamin Miller, Ikitesurf.com Meteorologist
El Niño has been the scapegoat of weather phenomena for years. In fact, the Peruvian fishermen who are credited with discovering El Niño in the early 1500’s viewed it as a curse. And not without reason, for the arrival of El Niño marks the beginning of an extended period of poor fishing for these generally productive waters. More recently, climatologists and meteorologists have recognized that El Niño brings many abnormal and adverse weather conditions to North American winters as well. Most well known are the destructive floods across California and the unusually warm temperatures across the Northern Rockies and Plains. But El Niño has been linked to many more subtle effects too. Just how will it impact your winter kiting plans?
WHAT IS EL NIÑO?
Put simply, El Niño is a disruption in typical ocean and atmosphere interactions. Ordinarily, easterly trade winds keep the warmer surface water piled up across Indonesia and north Australia, while cooler water upwells along the South American coast. However, this buildup of water can only last so long before the warmer surface water beings to propagate eastward. This sets off a series of shallow ocean waves called Kelvin waves, which help to transport the warmer water toward Peru and Ecuador. Once the warmer water arrives along South America it begins to spread northward and southward and impacts to North American weather patterns become more prominent. The biggest impacts are generally in the winter and spring months.
Hawaii: During El Niño winters, the North Pacific High dips farther southward than in ordinary winters resulting in a weakening of the northeast trade winds that prevail across the Hawaiian Islands. Because of the sagging North Pacific High, the jet stream is able to dip farther southward as well. This tends to allow storms to get closer to the islands. These storm systems don’t bring much rainfall (moisture gets shoved eastward and drought is a common problem in Hawaii during El Niño winters), but they do bring bigger than normal waves to the North Shore and stronger stints of northeast to northwest winds.
What adds considerable uncertainty to any extended forecast is that not all El Niño’s are created equal. However, preliminary data from the Tropical Atmosphere Ocean (TAO) buoy network and the majority of El Niño climate models indicate we’re in for a moderate El Niño for the 2009/2010 season. So, in general, the effects this season should be a bit muted compared to a strong El Niño year. El Niño will likely impact Hawaii with weaker than normal northeast trade winds, but stronger stints of winds from passing storm systems. El Niño brings cooler air temperatures and less thermal-driven wind.
Baja: iKitesurf.com meteorologist Mike Godsey has spent several winters in Baja and reports that the more southerly storm track of El Niño winters results in two significant impacts. First, Baja experiences cooler air temperatures and more cloudy days, meaning fewer moderate, or even mild, thermally-driven wind days. Second, the more active winter weather pattern, coupled with the more southerly position of the Four Corners high, results in a greater frequency of El Norte wind days, which typically lasts three to eight days. With the more active El Niño-driven storm track, these events will likely be more in the three to five day range.
However, one other factor is that the North Pacific High is generally farther south during El Niño winters somewhat negatively affecting the El Norte wind. As northwest winds come off the North Pacific High, they tend to drive the north-northeast El Norte winds farther from shore. In general, look for kiting conditions to be more challenging as stronger winds tend to remain away from the beaches.
Baja’s famed El Norte wind is often more frequent during El Niño but other factors during this weather pattern can make these winds more gusty and unsettled near shore.
California: El Niño events are infamous for bringing greatly increased amounts of precipitation resulting in disastrous flooding, especially in the January to March time frame. However, impacts to the winds are less obvious. In El Niño years, the jet stream tends to split with the storm track dipping more southward than in typical winters. This split weakens the strength of storms, resulting in plenty of precipitation, but less storm-driven wind.
After analyzing data from the last several years across the iKitesurf.com weather network, an interesting pattern emerges regarding El Niño winters. San Francisco winds tend to be generally weaker across the central coast, Bay, and Delta, due to cooler, cloudy, and rainier weather. However, springtime winds, especially across the Bay, begin to ramp up faster than normal. For instance, over the last three El Niño events at 3rd Ave. Channel (see Graph), the month of April has had 21 to 28 days in which the peak afternoon wind average was over 20 knots. Meanwhile, in non-El Niño years, the number of times in which the winds reached over 20 knots was only in the teens.
The impact of El Niño to southern California also tends to weaken winter winds. This is because of slightly cooler than normal weather and increased cloud cover that a company additional rainy days. As a result, there are less thermal wind days. El Niño is likely to bring a wet winter with more clouds and cooler days, resulting in less of a chance for solid winds. However, El Niño winters generally lend themselves to a faster strengthening of springtime winds (April/May) across the San Francisco Bay (especially the Central Bay and Peninsula sites). Additionally, during El Niño winters the Sierra Nevada typically receive abnormally heavy snows, making for great snowkiting conditions.
Texas: El Niño brings abnormal amounts of rainfall to the Gulf Coast, especially to south Texas. In fact, over the last century, rainfall during El Niño events has been nearly double that of non-El Niño winters. The increased rainfall means more clouds and generally cooler weather. Since Texas beaches are largely dependent on thermally driven sea breezes for winds, it is easy to see how El Niño tends to impact the region with lower winds. This impact is particularly notable in the early spring months (late February to April). For example, over the last 10 years, South Padre Island has seen 20- 25 days where winds peak at over 20 knots in the month of April in non-El Niño years.
However, in El Niño years, April has usually only seen 14-16 days where winds reached above 20 knots. El Niño brings abnormally wet winters to the Gulf Coast. This is particularly noticeable in south Texas. With cloudier and cooler days, solid days of wind will be fewer and farther between. This is especially true in the early spring when the more solid sea breezes are generally slower to return compared with non-El Niño years.
Florida: Impacts from El Niño on the Sunshine State are similar to the rest of the Gulf Coast region. Florida sees more precipitation during El Niño versus a non-El Niño winter. However, climate data reveals an interesting trend. Temperatures actually tend to remain above normal through mid-January. So, although El Niño brings additional rainfall and generally more clouds, winds tend to remain comparable to non-El Niño winters, at least through mid-January.
Then, temperatures tend to cool and thermally-driven sea breezes weaken a bit. Springtime winds (mainly March and April) during El Niño years have been historically a bit weaker across Florida. The lower wind impacts are greater for the Gulf Coast beaches than the Atlantic Coast. El Niño brings increased precipitation, but tends to impact the winds mainly in the spring. Effects seem to be fairly small for the Atlantic Coast, but greater for the Gulf Coast. If you’re planning to go kiting during spring break, I’d say stick to the central or south Florida coast.
CONCLUSION: El Niño is an irregular event that varies in intensity with each occurrence. Wind is driven and effected by countless mechanisms both large and small scale and El Niño is just one such mechanism. To say that El Niño will specifically cause or prevent a windy day is beyond any forecaster’s skill. Your best bet for maximizing your water time is to monitor the forecasts, wind trends, and real-time data for your favorite areas. iKitesurf.com is a powerful FREE weather service which includes access to over 45,000 weather stations and accurate model forecasts for riding spots worldwide.
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