My 2011 Hurricane Forecast

[Gastonwxman]

After an interesting 2010-2011 winter season despite most forecast calling what they did for the U.S., many are now beginning to wonder what the 2011 hurricane season will behold for folks this summer. During the previous hurricane season, we lucked out by hardly having any of the hurricanes and tropical storms make landfall since winds aided in steering the majority of these systems away from the U.S (just to name a factor). This year though, things are appearing to set up differently this go around as that threat now appears to be on the increase this go around, which we'll get into in a moment. I want to go over some analogs that could be possible candidates for this season. By the way mods, I will have no trouble with it if this topic needs to move if necessary to a more appropriate spot (I assume it would be fine posting a new topic about this on this part of the forum).

Analogs:

The ability to tie in a few years with similar setups for a particular current season can go a long way when analyzing the overall pattern that may or may not be conducive for something, which in this case I believe will help us figure out what could be in store for the US later this year. There are two years in particular that come to my mind: 1996 and 2008. During both of these seasons, there was an observation of a weakening Azores High, progressively warming Atlantic SSTs, and a positive phased AMO with a weakening La Nina/developing neutral (La Nada) ENSO in place but this is just to name a few of the factors that were involved. The 1996 season had 13 named storms, 9 of which were hurricanes and out of them, 6 were major hurricanes and the rest as tropical storms while the 2008 year had 16 named storms, half of which were hurricanes, 5 out of the 8 hurricanes as major hurricanes, and the other half were all tropical storms, though another tropical system before Paloma formed was around but had only made it to tropical depression status (16 to be exact). There are other good ones to use out there I'm sure but out of all the years that I looked at, these two in particular appear to be the closest to what I believe will be forthcoming for the season.

Azores/Bermuda High:

Next part I will discuss is regarding the strength and positioning of the Bermuda High. To recap for those of you who have forgotten, the Bermuda High is a subtropical high pressure system that develops over on the eastern half of the Atlantic aiding in the movement of the several tropical systems that develop as they traverse. Where that high sets up and how strong it is usually determines the track of which those disturbances take. However, that forecast alone is difficult to pinpoint, even as we speak for just a small adjustment can make a difference in the behavior of how tropical systems track. Right now it's anyone's guess on where it eventually sets up for the first half of the season since, just like a low pressure system, it has variability in movement. The Bermuda/Azores High has been known to reposition itself even during the hurricane season, which can cause a much different outcome to occur than previously thought. In any case, here are the three ways that it can affect storm tracks: A placement in the center of the Atlantic would guide systems toward FL and along the East Coast after traversing underneath, further west would steer them into the Gulf and through the Southeast, and further east will increase chances of recurvature to the north away from the U.S. coastline. Another case would be if the high is stronger despite being further east, it can still be powerful enough to push these tropical systems since it acts as a strong barrier, preventing northerly turning and forcing them to take a more southern route so there is that to consider as well. I'm going with an initially strong westerly displacement of the high for the first half of the season before pulling to the east for the second half, which will bring the tropical threats from the Gulf and eastward along the East Coast and New England region.

ENSO:

At this point, we now look to the current ENSO state, which is transitioning to neutral status. There is not much to say in this section except that despite the La Nina fading, the lingering circulation can still have an impact. Despite the warming that has been occurring in the Pacific, I don't foresee us getting saved by a developing El Nino, which may not show until the fourth quarter of this year (if it ever appears) or we regress back into La Nina. The ENSO should remain neutral throughout the period and also believe that it will not be detrimental to the expected conditions of this hurricane season, but it bears watching should there be a significant shift for the next several months.

Multi-Decadal Signal:

There is one important factor that we can tie in with this is something known as the Tropical Multi-Decadal Signal. Considering the signal of an upcoming above average season, this would mean a decrease in vertical shear which promotes increase chances for tropical systems to survive without interference, weak easterly trade winds allowing disturbances rolling off of the Western African Coast to travel along a more favorable African easterly jet and with that, this also acts as a provider for systems to feed off of the energy presented for tropical cyclogenesis. This also means the enhancement of upper level easterlies in the Tropical Atlantic region and increases rising motion beneficial for tropical systems. All of these factors are indeed present as indicated by guidance for about two months now and I would expect these conditions to persist as we progress through the hurricane season, once more continuing the tradition of the increased Atlantic activity that has been evident since the beginning of it 16 years ago (1995-present). This can also be linked with the current positive phase of the AMO, which it too plays a role in all of this by the increase in the appearance of stronger hurricanes but the number of weak systems that arise (tropical storms and weak hurricanes) has been proven to not be as affected by the AMO.

Atlantic SSTs:

As previously mentioned, with the AMO in the warm (positive) phase, the Atlantic for the most part should remain with above average water temperatures fueling developing systems. As of June 2nd, the Carribean region has been experiencing continued warmth with values at least 0.5°C; a good indicator of where cyclogensis would be most favorable in and would fit the idea of an area for initial tropical threat (along with the Gulf) with values exceeding that in the eastern tropical Atlantic region. The warmth is expected to continue for much of this season even as we get into the late months. The above average anomalies of the MDR SST and the difference of that with the Global Tropics shows that the result between the two is supportive for the idea of an active Atlantic season.

Predicted Storm Totals:

After reviewing much of the material and modeling, I have come up with the following for the number of storms. Here they are:

Number of Total Named Storms: 16

Number of Hurricanes: 8

Number of Major Hurricanes: 5

For the beginning of the season, I suspect that the Western Gulf and parts of the Southern Caribbean region will experience the storms first. During the mid and a part of the late period, this threat will shift further north and east, threatening areas such as FL and the interior Southeast, eventually shifting to more of a track along the East Coast and the New England region for the rest of the season.

Keep in mind that just as any other seasonal forecast, a great deal of things can change and may yield something that most, if not, all forecasts called for. This past winter proved just that with a prolonged cold period due to strong dual blocking making the winter colder than forecast. I expect the multi-decadal cycle to remain supportive for continuous active Atlantic hurricane seasons until at least 2015, if not later. Much can easily change once we get the season going but we shall see what plays out in the end. Here's to another year of hurricane watching. Hope you enjoyed my forecast. Would love to hear some comments out of you folks, or even suggestions. TIA.

[Cyclonicjunkie]

Very excellent writeup

[buckeyefan1]

I'll second the above post.

[buckeyefan1]

I'll second the above post.

[jrips27]

Nicely done!

[Carvers Gap]

It will be interesting to watch the ENSO signal. If it goes to a Nino state early, the hurrican season will evaporate. On the plus side(which I hope you are correct!), if is switches late in the year to a weak Nino this winter could be banner or even if the ENSO stays neutral. In E TN, weak El Nino's have the potential to produce incredible winters.

http://www.cpc.ncep.noaa.gov/products/predictions/90day/fxus05.html

[Gastonwxman]

It will be interesting to watch the ENSO signal. If it goes to a Nino state early, the hurrican season will evaporate. On the plus side(which I hope you are correct!), if is switches late in the year to a weak Nino this winter could be banner or even if the ENSO stays neutral. In E TN, weak El Nino's have the potential to produce incredible winters.

http://www.cpc.ncep....day/fxus05.html

That will definitely be something to keep watch of. I have seen neutral years where a sudden swing took place in a matter of a couple of months during a particular season, resulting in some interesting effects which caused a great deal of variability in the model data output (and ultimately a series of unexpected turn of events regarding tropical activity). If I had to take a guess at what we would be looking at come the SON period, I'd say a weak nino would be developing and reaching its peak by sometime in December. However, considering the fact that this is way out there and from what you can see from the ENSO chart I posted, most of the modeling agree toward a continuation of a neutral status, which would oppose my thinking of what happens during the second half of the hurricane season. In this case, it is for the worst of the activity to occur between mid September and mid October. We'll see. I'd be surprised if we somehow pull off getting warmer SSTs in the Pacific emerging in time for the next winter but won't hold my breath for that just yet.

Speaking of winter, I'm already seeing some folks mentioning possibilities about this upcoming winter already for the Southeast. I won't go into details about my thoughts for the upcoming 2011-2012 winter season until much later this year (which I'm aiming for the release of that forecast to be during early November when the time is right). By then, either the majority of the modeling pans out and we stay neutral or we potentially shift to an El Nino but will not rule out a back-to-back Nina episode occurring either so it all bears watching. No guarantees on where we go from here obviously but there are a lot of things to look at and that just further decreases my confidence in the latter part of this year. Just a matter of patience now and hopefully we will have a much better handle of this winter compared to the one we just went through. That one was one of, if not, the toughest I've ever tried to get a handle on amongst all others.

No tropical troubles to speak of at this point. Our little disturbance that had potential to become our first active system is long gone through the Atlantic now after experiencing several days of strong upper level wind shear. Highest wind was reported at 30mph with several showers and thunderstorms erupting around the center in the Caribbean, gradually losing its organization the further north (and eventually northeast) it went and was eliminated from future predictions since it only had a 10% chance of significant tropical development at that point. However, if you had heard about it like a week ago, just off the west coast of Mexico, Adrian immediately became the first major hurricane (reached Cat. 4) to develop not too long ago. Even it has since fizzled out the further it traveled from warmer waters. Here were the stats on it for its life span:

Name: Hurricane Adrian

Highest Category: 4

Location: East Pacific

Max Wind Speed: 140mph

Minimum Pressure: 27.94 (946mb)

Lifespan: 6 days (June 6-12)

Current Atlantic View (Rainbow satellite imagery)