State of our Surf: Summer 2006

Nathan Todd Cool, Chief Forecaster, WetSand.com
June 10, 2006
See also:
   * Hurricanes 2006
   * Global Warming Percolates Long Range Surf Forecasts

While California was getting wet during a precipitation record-breaking April, the southern hemisphere was getting quite active and south swells began to brew. Storms were stirring up down under while rain pelted the west coast of the U.S. Shortly thereafter, the east coast of the U.S. felt some powerful surf and flooding rains. But even more bizarre shifts in surf-producing climate were afoot during this time.

After shifting rapidly from an El Niño in the winter of 2004 to a La Niña in 2005, conditions as of late have quickly returned to normal--whatever that may be, in what now seems to be a wild fluctuation of Mother Nature’s mood swings. After enduring record-breaking hurricanes over the past couple years, all ears are tuned into the sounds of climate change. While it may be premature to ring the global warming alarm bell on recent shifts in weather and resultant surf this year, we do know that 2006 will not be exactly conventional in the way of waves. Although the Atlantic has made the headlines in recent weeks with hurricane predictions for this summer, the Pacific will be seeing some shifts as well.

Taking a look at the state of our surf for the summer of 2006, we can see that there will be a wide variation in surf depending on where you plan on catching some waves this year. To cover this wide gambit of global wide waves for the upcoming months of fun in the sun, I’d first like to discuss a synopsis of the Pacific and Atlantic sea states, then provide a perspective on what to expect in the way of surf in three particular regions:

• California and the West Coast
• The U.S. East Coast
• Travel Destinations including Hawaii, Central America, and the Bahamas

Synopsis

ENSO conditions have recently shifted to a neutral state while lingering from the weak La Niña of last year. This has put the Pacific in a near neutral state for sea surface temperatures, especially in the equatorial zones. This is having a few primary drivers on both Pacific and Atlantic oceanography:

1. The southern jet stream near Antarctica is not as weak as it recently was, and can have an effect on southern hemi southwest swells for Pacific regions like California, Central America and Hawaii.

2. The jet stream in the northern hemisphere will likely be somewhat stronger over hurricane alley, which may increase vertical wind shear ever so slightly, but not enough to diminish hurricane formation significantly. Yet the wind shear will likely be higher in the tropical Pacific.

3. The tropics in the Pacific are now a bit warmer than last year with potential for some additional hurricane activity in the eastern Pacific.

We also appear to be in a decadal cycle for positive hurricane formation; however, this cycle continues to be stronger than normal, primarily due to warmer than normal waters. As mentioned in recent articles (here and here) this may very well be due to global warming effects, yet this is still under investigation. In either case, worldwide ocean waters--especially in the Atlantic--are now warmer than normal, thus providing the primary fuel for cyclone formation.

Additionally, the African Easterly Jet stream (AEJ) is once again favorable for guiding storms across the Atlantic to the U.S. east coast, the Bermuda High is expected to remain in a similar state as recent years, and overall, Atlantic sea surface pressure will likely be lower than normal.

This all adds up to a mixed medley of Mother Nature’s ballads of breakers, symphony of swells, and songs of sweet, yet at times quite sour and savage, summertime surf.

California and the West Coast

The ENSO cycle flip-flop over the past couple years--rapidly shifting from El Niño in 2004 to La Niña in 2005 and now neutral--is playing havoc on jet streams in the north guiding the NW swells and also the southern jet that steers the deep southern hemisphere swells. Since ENSO events displace the normal formation of high and low pressure systems, the radical swings as of late are having an effect on the guidance of forming swell energy. The displacement of high and low pressure systems is kind of like moving around large boulders in a stream of flowing water. When you move a rock in a stream, the water is diverted in different directions depending on where you place the rock. When the ENSO moves the low and high-pressure weather systems, it has a similar effect on the jet streams, which guide along most of our swell making storms.

During a neutral state of ENSO, we could expect things to be considered normal. But with the rapid shifts of late, things are not exactly as they seem. Nevertheless, an overlying trend of southern hemi swells will prevail this summer; they’ll just be affected somewhat differently.

Since we’re moving away from a La Niña, the southern jet will likely become a bit stronger, and tend to hold southern hemi swell making storms in its grip. Still, the jet should not be nearly as strong as it would be in an El Niño cycle, so swell-producing systems should be able to break free and traverse northward, which would throw good amounts of swell energy at the California coast. Combine this with a very active ice cap--where so far this year more storms than normal have been spinning off this icy realm--and we have a good chance to see quite a few southern hemi SW swells, yet nothing that would traverse so well to the north that double overhead becomes the norm. Instead, many of the southern hemi swells this summer will likely be chest to head high. This of course is an average diagnosis and there will inevitably be larger and smaller swells from time to time. Yet if we were in the grips of an El Niño--or if our neutral state starts to shift that way--size and occurrence-frequency of these swells will wane since the southern jet would likely become stronger and hold swell making storms close to the ice cap. Since we are shifting from a La Niña to neutral, this scenario is not out of the question, but is not likely to occur for the next couple months.

The northern hemisphere is still a bit active and the jet stream is just a tad lower than normal. While the California NW swell season is pretty much done and over with, the month of June will likely see some added wind swell from time to time, which should completely fade to rare occurrences by the end of June.

Besides the wind swells, wind itself could be a concern, at least through June. The Gulf of Alaska has a persistent high that has been interacting with lows near the Sea of Cortez. This has built gradients around the California coast that would keep winds more reminiscent of April or May with northerly winds possibly problematic at times. Note that these kinds of winds also affect upwellings, and waters could cool from time to time through June as a result.

Looking at potential hurricane swell, NOAA’s Climate Prediction Center is calling for a mild to moderate hurricane season in the eastern Pacific with an 80% probability of a below hurricane season, a 15% probability of a near-normal season, and only a 5% probability of an above-normal season. This forecast calls for the North Pacific hurricane season to see 12 to 16 tropical storms (average is 15 to 16), with 6 to 8 becoming hurricanes (average is 9), and 1 to 3 becoming major hurricanes (average is 4 to 5).

This aligns with the ENSO neutral state that we’re in at the moment, as well as the decadal oscillation that is enhancing Atlantic hurricanes over the past few years. Additionally, hurricanes that do form will likely not live for very long as waters are in a neutral temperature range at the moment. However, if we do slide more towards an El Niño, the water temperatures in the eastern Pacific will rise, which could then enhance hurricane formation.

Taking into account the state of the Pacific Tropical zone, surf-worthy hurricanes will likely be few, yet as with most neutral state years, some south swells can be expected from these tropical storms in SoCal around August into September. Still, the size of the surf from these hurricane swells should remain moderate at best with better size coming in from deep southern hemisphere swells mentioned earlier.

The East Coast

Of the utmost concern this summer for the east coast will be hurricane formation. As I mentioned in my last article (here), everyone’s been talking about a once again active hurricane season in the Atlantic. Waters are warmer than normal, and seeing as though we’re also in a positive decadal cycle for hurricane formation, all elements are in place for another doosey of a year.

The Climate Prediction Center issued its most recent forecast on May 22nd, which says that there’s an 80% chance of an above normal hurricane season for the Atlantic. This outlook calls for a very active 2006 Atlantic hurricane season with 13 to 16 named storms, 8 to 10 hurricanes, and 4 to 6 major hurricanes.

In gauging hurricane ferocity, NOAA uses an index known as the Accumulated Cyclone Energy index, or just ACE for short. Click here to see the latest ACE chart. This ACE index is a culmination of various factors that relate to just how strong hurricanes on average are over a particular season. In techy terms, the ACE index is a wind energy index, defined as the sum of the squares of the maximum sustained surface wind speed measured every six hours for all named systems while they are at least tropical storm strength. In simple terms, a measure of the ACE index can tell us just how intense a hurricane season is (or is forecast to be). A near-normal ACE measurement in the Atlantic runs around 60 to 103%. The anticipated ACE for 2006 though has been set at an astonishing 135 to 205%.

Most of the intense hurricanes for 2006 in the Atlantic are expected from August to October. But as we saw last year, having water temps warmer than normal, a weaker jet stream, reduced vertical wind shear, a favorable African Easterly Jet and Bermuda High, conditions could spell trouble beyond the bounds of this forecast.

Another concern for the Atlantic’s hurricane season this year will be strike potentials. Accuweather issued a report on May 15th ( click here for report) that summarizes their expectations for hurricane strikes along the east coast. Based primarily on historic weather patterns that are correlated to prior hurricane seasons, the Accuweather report calls for a surprising strike zone with six tropical storms making landfall along the U.S. coastline. Of these six, Accuweather feels there will be three major hurricane hits this year on the United States coast, two hurricanes of Category 2 or less and one tropical storm. AccuWeather is also forecasting that two areas will be sitting in the danger zone:

1. The Carolinas northward at the heart of the hurricane season and
2. The Western Gulf Coast and Southern Florida earlier in the season.

While the Atlantic hurricanes could indeed produce surf for many locales along the east coast, the risks of damaging winds, rain, and loss of life are of grave concern. One item we’ll be watching closely over the next few months that could determine whether we’ll see safe surf or horrendous hurricanes, will be the position of the Bermuda High. This area of high-pressure sets up around Bermuda and stays put for much of the hurricane season in the Atlantic, and like all high-pressure systems in the northern hemisphere, spins clockwise. As this massive high-pressure system spins, hurricanes passing under it get caught in the periphery of its circulation and get steered one way or another. If the Bermuda High is small, and located where it normally is, hurricanes passing underneath of it caught in the spin of the Bermuda High are thrown northward, thus being diverted away from a direct hit on the east coast of the U.S. But in 2005 and in 2004, the Bermuda High was not sitting in its usual position. With its leading edge precariously close to the east coast, the Bermuda High was swinging incoming hurricanes directly at America’s eastern seaboard and the Gulf of Mexico.

If the Bermuda High can maintain a normal state (or reduced), then Atlantic hurricanes have a better chance of staying away from the coastline, and only providing waves to east coast beaches. But, if the Bermuda High continues its recent trend, then land-falling hurricanes will be a much greater point of interest.

Travel Destinations

With a very active hurricane season expected in the Atlantic, Bermuda and Bahama vacations this summer may not be ideal. Looking towards the Pacific however, things are looking much brighter.

Central American Pacific regions like Costa Rica will be seeing similar southern hemi swells as California. As mentioned earlier, we will likely see an average or slightly above average southwest swell season. For Central America, this means a good deal of southerly swells running a few feet overhead to double overhead. The regularity of swell occurrence though is looking moderate--just as with California’s outlook. Thus, there could be days or even a week or more between SW swells that bring in surf bigger than head high.

While timing will be critical in planning a trip to the equatorial Pacific regions this summer, the conditions will likely remain moderately favorable. Hurricane formation should remain at or below normal, so wind swells, winds, and land-falling storms should be rare to nil. If however we shift further from our current neutral state to an El Niño--which is not out the question given the rapid shifts in ENSO over the past couple of years--then hurricane formation could intensify later this summer into the fall months. Current thinking rules that out, but Mother Nature is the one holding the cards on this one.

Hawaii is less iffy in that the Climate Prediction Center is only calling for 2 to 3 tropical systems in all for the Central Pacific region. While being at a far lower risk of effects from tropical storms this summer, Hawaii should still see a good deal of southern hemi south swells, similar to California in size.

Mother Nature is sure a tricky ole gal. Just when we think we have her all figured our, she tends to throw curve balls our way. Who would have guessed that 2005 would see 28 named storms in the Atlantic? And who would have guessed that the ENSO cycle would shift so radically from El Niño to La Niña to neutral state over the past couple years? Our world of weather and the surf created by nature’s most powerful storms across our planet’s oceans is a force controlled not only by the laws of physics, but also by chaos and unpredictability. While confidence is high on my forecast for the summer of 2006, only time will tell as we keep an eye on the horizon, and watch time and weather unfold before us.

As always, we’ll maintain a close watch on the ocean waters and the surf headed our way, so that you’ll always, Know When with WetSand WaveCast.

--Nathan Cool

Nathan Cool is the founder of WaveCast, the Chief Forecaster for WetSand.com, an associate member of the American Meteorological Society, a professional member of the American Association for the Advancement of Science, and a member of the National Weather Association. Nathan is the author of many books including The WetSand WaveCast Guide to Surf Forecasting and most recently, Rhythm of the Ocean. More information on Nathan can be found at his web site:
http://nathancool.com/

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