It's time again to for the summer hurricane seasonal forecast. I've been doing these long range forecasts for the past year or so, and I hope to improve each time.
Looking at all the hurricane season forecasts,( NOAA, CSU, AccuWeather, WeatherBELL, Tropical Tidbits, etc)…and all the data and model forecasts, It looks to be a less active season than last year, despite the early start.
Here in south Florida, we really only have two surf seasons, Winter and Summer. As we all know, winter is the ‘ON' season and can be packed with groundswells, refraction swells, and windchop, while the summer ‘OFF' season is predominately controlled by the tropics and Hurricane season. So that's what I'm going to focus on in this forecast.
The consensus is that we are going to have a near normal to below normal hurricane season. Most of that is thanks to a weak El Nino forming. The past two years have had a La Nina pattern, which favors hurricane development.
El Nino's usually favor the East Pacific Hurricane season, which we've already seen the start of with tropical storm Aletta and behind it, Bud. The upper level blow off from an active Pacific creates a lot of wind shear in the tropical Atlantic, impeding tropical cyclone development in the deep tropics of the Atlantic.
Another inhibiting factor is water temperatures in the deep tropics have cooled considerably from the record highs that they were the past two years. And with that we have warmer than normal water to the north, along with the cooler than normal tropical waters. That usually is not favorable for upward motion, which is a big factor in getting systems started in the tropics.
This will also mean we will have less "long track" storms or Cape Verde type storms that track all the way across the Atlantic for weeks. That's unfortunate because those are the ones that send a nice few days of groundswell (upcoast at least). We're not talking none, but there won't be a flurry of them this year.
All-in-all the 2012 season won't be a dud, but will be less active overall from the previous two years.
Here's why it won't be a dud….the storms that do form, will more of the "home grown" variety. Meaning, they will develop close to land, and make landfall somewhere. We will see more storms develop in the sub-tropics, than the deep tropics.(Think of the whole state of Florida as the sub-tropics, drawing a line westward through the gulf and eastward into the Atlantic along the same latitude.)
In fact, Joe Bastardi, a renowned hurricane forecaster who works for WeatherBell now says "development of over 50% of the storms may be within 300 miles of the US coast." And he continues by saying "While the total package(season) may be down, the focus of the package(season) may be close to the coast rather than out to sea."
Here's a great graphic from WeatherBell that sums it up:
The redeeming factor to this is that the storms that form close to the coast, usually don't have time to grow into CAT 5 hurricanes. This would mean some victory at sea surf conditions, but also some really fun clean-up sessions, without getting us kicked off the island. We don't need a hurricane to give us waves, a nice close by tropical storm does the trick. We've already seen this this year with Alberto and Beryl forming close to the coast.
Also, remember Fay and Hanna in 2008?? It They were only tropical storms when they were close to us but gave us epic surf:
Colorado State's prediction is for a slightly below average season. They also go on to say a below average probability of a major hurricane hitting the US. Now, below average doesn't mean none, Look at hurricane Andrew in 1992. This is the 20 year anniversary of that cat 5 storm that hit Homestead. 1992 only had 9 named storm, and was very slow to get going, in fact it was the one of the latest seasons to name a storm, August 17th. Unfortunately that storm was Hurricane Andrew and it made a bee line right for south Florida causing $26 billion dollars in damage and killing 60 people.
As far as timing, The 2012 Hurricane season should get started early, possibly even at the end of May. Some models really want to develop something off that old frontal boundary sitting in the Atlantic. Either off South Carolina, or in the NW Caribbean…or both. The best model to watch for hurricane season is the European, or ECMWF. It has been outperforming the rest for the past 6-8 years now. The GFS is really the only one that goes super long range, but it's out to lunch half the time with it's predictions. Don't be fooled by seeing a big hurricane off our coast every other week by the GFS, especially the start of hurricane season.
The usually quiet first couple months of the season (JUNE-JULY) will
be more active than usual, then as El Nino gets going, the second half of the season will shut down. That's when we normally get some good ‘cane swell. But don't throw in your towel yet, there are early indications that fall will start early in the northeast, and if that's the case, we would be seeing some good early north groundswells that do make it into south Florida instead of having to drive upcoast for hurricane swells.
The NWS in Miami is forecasting near to above normal precip for late may and June, then near normal precip for the rest of the rainy season. Which goes in line with what is forecasted for hurricane season.
- So to recap hurricane season:
- Early start to the season
- More home grown storms then long trackers.
- Generally weaker systems
- Season winds down early
- Early start gives us hope through the flattest months, June and July
- Closer storms offer swell that will make it to south Florida, not just upcoast.
- No big long tracking storms means swells will be short lived.
- Weaker systems mean less evacuations and more time to surf
- Season ends early but fall may start early too so we may get right into north swells while still in hurricane season!
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