Expert forecasts for 2013 N Atlantic season

[TropicalAnalystwx13]

"There are no mitigating factors that we can see that will suppress the activity," said Gerry Bell, Noaa's lead Atlantic hurricane forecaster. "The computer models all point to an active, or very active, hurricane season."

[Hurricane Jed]

Interesting. This could be a nasty season.

[Alyono]

if conditions are more favorable than they were last year, shouldn't there be more storms this year than last?

[ROCK]

i think they hedging their bet some with 13-20 storms and 3-6 majors. JMO

[JonathanBelles]

FSU Will release it's forecast on the 31st.

http://coaps.fsu.edu/hurricanes

[cycloneye]

The TSR folks released their preseason forecast on Friday and is posted on the first post.

The highlights of this May 24 forecast are:

•15 tropical storms including eight hurricanes and three intense hurricanes. This compares to long-term norms of 11, six and three respectively.

•An ACE (Accumulated Cyclone Energy) value of 130. The long-term norm is 103.

•Four tropical storm and two hurricane landfalls on the U.S. mainland.

The key factors behind the TSR forecast for an above-norm hurricane season in 2013 are the anticipated persistence through summer 2013 of warmer-than-normal sea surface temperatures in the tropical North Atlantic, and an expectation of neutral or weak negative ENSO conditions in the tropical Pacific Ocean. These factors would help to energise and sustain more storms.

[RL3AO]

if conditions are more favorable than they were last year, shouldn't there be more storms this year than last?

Number of tropical storms is meaningless now (in my opinion) when it comes to determining how active a season is. 2012 had so many storms that were weak systems that probably don't get named 20 years ago. I think the ACE will be higher and the number of hurricanes/major hurricanes will be higher this season. In addition, just the fact that the Caribbean was so unfavorable last season, a normal season this year could still be worse in terms of impact then last year.

[Alyono]

if conditions are more favorable than they were last year, shouldn't there be more storms this year than last?

Number of tropical storms is meaningless now (in my opinion) when it comes to determining how active a season is. 2012 had so many storms that were weak systems that probably don't get named 20 years ago. I think the ACE will be higher and the number of hurricanes/major hurricanes will be higher this season. In addition, just the fact that the Caribbean was so unfavorable last season, a normal season this year could still be worse in terms of impact then last year.

weren't there 10-11 hurricanes?

[RL3AO]

Yeah there were. I think people, including myself, are relating a more active 2013 with the idea that land impacts seem much more favorable this year. The deep tropics/Caribbean appear much more favorable compared to the sub-tropics favored tracks of last season. Even if its a 15/7/4 season, there will likely be much more impact than 2012 (although hopefully nothing like Sandy).

[ROCK]

TSR really goes out on a limb with their forecast. Remains unchanged from the last 2 updates...

[cycloneye]

Penn State University forecast is posted at first post.

[Cyclenall]

I heard that the Canadian Hurricane Center also issued their forest numbers or general opinion. I heard on TWN that they were going with NOAA's choice of active to extremely active. I don't know if its just a case of them copying NOAA or actually releasing an independent forecast. All the articles just state the CHC's thought but no actual source. Maybe this has something.

[cycloneye]

I heard that the Canadian Hurricane Center also issued their forest numbers or general opinion. I heard on TWN that they were going with NOAA's choice of active to extremely active. I don't know if its just a case of them copying NOAA or actually releasing an independent forecast. All the articles just state the CHC's thought but no actual source. Maybe this has something.

What I read there is they are talking about what NOAA said but I don't see any forecast by them.

[hurricanexyz]

it is unlikely that they will be less than 16 named storms this year

[Hurricaneman]

it is unlikely that they will be less than 16 named storms this year

The conditions in the atlantic would say so but you cant tell if some unknown will knock the numbers down, but it is better than 50% that we see 16+ named storms

[cycloneye]

The next three new forecasts that will be added to the first post list will be FSU on May 31,CSU on June 3 and TSR on June 4 so stay tuned for that.

[Macrocane]

Number of tropical storms is meaningless now (in my opinion) when it comes to determining how active a season is. 2012 had so many storms that were weak systems that probably don't get named 20 years ago. I think the ACE will be higher and the number of hurricanes/major hurricanes will be higher this season. In addition, just the fact that the Caribbean was so unfavorable last season, a normal season this year could still be worse in terms of impact then last year.

weren't there 10-11 hurricanes?[/quote]

Yes, there were 10 hurricanes. The only storms that probably wouldn't have gotten a name years ago were Oscar, Patty and Joyce.

[vbhoutex]

Jeff Lindner posted this today.

Saturday, June 1 marks the start of the 2013 hurricane season in the Atlantic basin which includes the Gulf of Mexico and Caribbean Sea. As widely noted over the past few days the 2013 season is expected to be active to extremely active with the number of named storms likely exceeding the historical 30 year average of 12. The forecast calls for:

13-20 named storms (tropical storms)

7-11 hurricanes

3-6 major hurricane (category 3 or higher)

Both atmospheric and ocean conditions across the Atlantic and Pacific are looking favorable to very favorable for tropical cyclone formation, but it should be clearly understood that the forecast for an active hurricane season does not indicate where or if a tropical cyclone will impact the coast.

The following factors/indicators point toward an active season:

1. Warmer than normal Atlantic sea surface temperatures especially in the region between the African coast and the eastern Caribbean Sea where tropical cyclones tend to generate in the late July-mid September period. Warm water temperatures add more “fuel” for tropical cyclone formation and intensification.

2. Forecasted sea level pressures in the area from Africa to central America are expected to be near normal during the peak time (Aug-Oct.) this year suggesting favorable conditions for tropical cyclone formation

3. The lack of any significant El Nino event in the Pacific Ocean is another favorable factor which helps to limit wind shear effects on Atlantic tropical systems.

4. The Atlantic Basin has been in an active state since 1995 (known as the Atlantic Warm Phase) in which hurricane seasons tend to be more active with stronger storms.

While these factors point toward an active hurricane season they do not help to indicate where the greatest risk for landfalling systems may be. For this reason it is advised that all coastal regions have a hurricane plan and kit and make sure those kits are stocked and ready to be used should a tropical system threaten your area.

A few items to keep in mind:

Tropical systems are not a point and have far reaching effects and impacts. The typical error cone shown in National Hurricane Center graphics does not represent the location of impacts, but the error in the forecast track over the past 5 years at the forecast point in time. For example the update error circles for 2013 (2008-2012) are:

12hr - 33 miles
24hr - 52 miles
36hr - 72 miles
48hr - 92 miles
72hr - 128 miles
96hr - 177 miles
120hr – 229 miles

Preparation should be the same across the entire error cone regardless of where the center is expected to landfall.

Recent destructive hurricanes have shown the ability of storm surge to inundate and destroy coastal locations (Katrina, Ike, Rita, and Sandy). The forecasted storm surge is a combination of several factors including the coastal topography, the forward motion, and intensity, and most importantly the radius (how far) the strong winds extend from the center. It is incredibly important that residents focus on the forecast of storm surge and not the hurricane category. The category is a wind based scale and does not indicate the storm surge threat. Storm surge forecast will be impact based and noted in both above mean sea level and above ground level.

Computer model guidance is now widely available on the internet and via many media. Model guidance is just that…guidance…it is NOT “what is going to happen”. For anyone who has followed model tracks and guidance they can greatly vary between each model run (every 6 hours). Hurricane forecasters do not make big jumps each time the models jump one way or the other to avoid the “flip flop” effect. Widely varying solutions tend to lead to lower confidence forecast tracks while tight clustering suggest good agreement and higher forecaster confidence on the track. While model guidance is far from prefect, it is significantly better especially on the track forecast than even just a few years ago. Intensity forecast still have large error especially when concerned with rapid intensification which tends to be under-forecast on the models. This is generally a result of a lack of understanding of inner core dynamics.

[SFLcane]

FSU COAPS Atlantic Hurricane Season Forecast http://coaps.fsu.edu/hurricanes

12 to 17 named storms, including 5 to 10 hurricanes

[cycloneye]

FSU forecast is posted at the first post.