Eastern Pacific Hurricane Watch - "Yo Adrian!"
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Updated June 10, 2011 Rocky Balboa would certainly have something to shout "Yo Adrian" about this past week. The 2011 Eastern Pacific Hurricane Season is off to a flying start with Category 4 Hurricane Adrian. Adrian formed from the first tropical depression of the year and quickly powered up in just 36hrs to a Major Hurricane. (Category 3 or greater) These early season storms rarely threaten land and move off harmlessly into the Pacific. The image left shows Category 4 Hurricane Adrian at full force off the southern coast of Mexico.
Just as a note we are still about 60 days away from the usual "Baja Hurricane Season".
The early season usually spawns one or two of the Eastern Pacific’s three Major Hurricanes of each year, but Adrian was particularly early. Some of the warmest waters are seen off the southern coast of Mexico in the early season. Waters 29°C and warmer exist early in the summer and actually contract as the sun moves further north toward the Tropical of Cancer which runs through southern Baja California Sur. These are the very warm waters which spawned Adrian.
Although the Eastern Pacific Hurricane Season starts on May 15th it is usually the third week of May before we see our first storm. Six years ago, in the cycle of naming hurricanes, Adrian was also a freak storm. Developing off the coast of El Salvador on May 17th, 2005, Category 1 Hurricane Adrian came ashore in the usually ‘hurricane free’ area between El Salvador and Guatemala. Since the area doesn’t get many hurricanes the region was caught unprepared and many died.
As for early June Major Hurricanes, Adrian is again a freak. It has been 10 years since a major hurricane occurred before the third week of June. In 2001 Category 4 Hurricane Adolfo raged the last week of May and the first week of June, just a few days and 10 years ahead of Hurricane Adrian. Hurricane Adolfo was the earliest major Hurricane in the last 15 years, Adrian is the second earliest Major Hurricane.
As you can see from the plot graphic, the two storms followed very nearly the same track. Over the past 15 years these are the two earliest storms to achieve Major Hurricane intensity.
What does it mean? Well, to call a season based on one early storm would be just plain silly. Like last year there is already an apparent dearth of tropical waves. Last year, 2010 provided the fewest number of tropical waves to enter the Eastern Pacific that I have seen in the 8 years of tracking tropical cyclones here on the Insider. In 2001, the year of Adolfo, Baja was hit by Hurricane Juliette. Hurricane Juliette hammer the tip of the peninsula, roaring right up to the coast as a hurricane but making landfall twice as a tropical storm in the third week of September.
In terms of the ENSO (El Nino Southern Oscillation) in 2001 we were coming out of a weak El Nino into a neutral year. This year we are coming out of a moderate to strong El Nino to a neutral year. Neutral years produce few hurricanes in the Eastern Pacific but more landfalls in Baja.
On June 9, 2011 the Climate Prediction Center, part of NOAA analyzed the trends of the ENSO or El Nino current. Despite increased Sea Surface Temperatures along the equator in the Eastern Pacific, The subsurface waters appear to be moving into an El Nino neutral phase, with upper level winds in the Central Pacific diminishing. (see original NOAA Document)
Enough about history, let’s look at this week’s data. The Eastern Pacific is warming up. This weeks SST graphics do not show the full influence of Hurricane Adrian. Hurricanes are nature’s natural engine for displacing equatorial energy northward. Hurricanes release as much energy as a 20 megaton nuclear weapon every 20 minutes. Next week we should see some cooling of the Sea Surface along the path of Adrian.
An interesting aspect to Adrian is how it ‘followed’ warmer waters. Born in +30°C waters along the southern coast of Mexico the storm curved northward as it entered the cooler waters to the west. (see The Sea Attracts Hurricanes) It isn’t like the storms have a sense of warmer waters but they do seem to have a will to survive.
Seasonal Sea Surface Temperatures |
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Animated SST's from May 14 to Present |
What happens is the side of the hurricane that is over warmer waters supports greater evaporation. Thus that side of the storm becomes heavier and drags the storm to the heavy side. Now, there are a lot of factors affecting the path of the storm, upper level winds being the dominate factor. But the availability of warm water certainly affects the path of the storm.
To read the long range season forecast for 2011 click here
We animate the Sea Surface Temperature Analysis and Anomaly graphics for each update and weekly on our Tropical Weather page. On the right we see the Sea Surface Temperatures from May 14 to June 11. The all important 26°C thermo cline has not move significantly in the region south of Cabo San Lucas. The Sea of Cortez has warmed significantly over the last month, but it is that 26°C thermo cline that determines how far north a tropical cyclone can live. Tropical cyclones are usually spawn in waters warmer than 28°C and die quickly when crossing into sub 26°C waters. (this can be seen on the Path graphic above as well)
Seasonal SST Anomaly °C |
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Animated SST Anomaly May 14 to Present |
The sea temps for most of the Eastern Pacific Hurricane Basin are slightly above normal in this graphic for the week ending June 11. This animation left shows the relative temperature difference. We can see a small bubble from the Bay of La Paz southeast that is about 1°C above normal. The rest of the basin is a light shade of yellow, indicating less than 1°C above normal. With the passing of Adrian last week we are likely to see a return to normal conditions in next weeks graphic.
When we look at the wide angle surface chart below we can see we might be in for an active week ahead. There are three tropical waves headed across the Atlantic and Caribbean, headed for the Eastern Pacific. The first tropical wave of the season stimulated the formation of Adrian. The second wave, if you can call it that, sputtered out over the Panamanian Isthmus. The ITCZ in the Atlantic is still traveling south of the 10° latitude, where storms are unlikely to form and energy from these waves unlike to be used up in the Atlantic. With a little more evaporative moisture along the ITCZ in the week ahead it is likely that one of these three waves will spawn a storm.
Looking at the week ahead..
Now for the fun part. Each Hurricane Watch I gaze into the crystal ball and break out the Ouija board and make my predictions for the period ahead.
My first prediction went badly; I didn’t expect any storm formation in the 14 days ahead of the report. Of course you know we had Adrian. But Adrian formed 19 days after my prognostication. But I accept it as a ‘loss’.
In the two week period ahead we WILL have some more tropical cyclones. Late June can be very active in the Eastern Pacific, as by the 15th of the month we move into a period of about 1 storm every other week through the end July. So I’m really hedging my bets to say we will have a tropical cyclone in the next week and one on the way when this forecast ends in two weeks.
I think we’ll see another moderate storm move off into the Pacific and die a lonely death without landfall.
But what do I know…
See you in two weeks!