April 2013 Hurricane Season Forecast

2013 Hurricane Season is fast approaching. Tropical Storm Risk, ImpactWeather, CrownWeather, and Joe Bastardi have issued their April 2013 forecast. Keep in mind this is very preliminary at this time as things change.

Tropical Storm/Hurricane/Major Hurricane ACE=Accumulated Cyclone Energy ACE/Storm

Colorado State University
18/9/4 ACE: 165

Tropical Storm Risk
15/8/3 ACE: 134

16 to 20 Storms/7 to 9 Hurricanes/Did Not Release Major Hurricane Numbers ACE: None

Joe Bastardi
16/12/5 ACE: 165

North Carolina State University
13 to 17 Storms/7 to 10 Hurricanes/3 to 6 Major Hurricanes ACE: None

Right now, the Pacific Decadal Oscillation (PDO) is in a cool phase, while Atlantic Multidecadal Oscillation (AMO) is in a warm phase. We are right now in a Neutral phase of El Nino Southern Oscillation (ENSO) as this past winter was. Most forecast models have ENSO in a Neutral phase to Fall (Northern Hemisphere) or Spring (Southern Hemisphere) 2013. Forecasting El Nino is very tricky and often comes out incorrect as it happened last year and in 2006.

Mid April 2013 IRI/CPC Plume-Based ENSO Forecast

Mid April 2013 IRI/CPC Plume-Based ENSO Forecast

Mid-April 2013 ENSO Predictions Plume

Mid April 2013 ENSO Predictions Plume

Based on phase of PDO, AMO, and previous winter ENSO, the analog seasons for 2013 are 1952, 1960, 1961, 1966, and 2004. Those years started with a Neutral, Weak El Nino, or Weak La Nina and went Neutral, Weak El Nino, or Weak La Nina by the peak of hurricane season to end of the year. 1966 started with Weak El Nino and went to Weak La Nina by end of that year. 2004 started as Neutral and went to Weak El Nino by end of that year. It shows that ENSO is difficult to predict and left leeway as a result. On the other hand, PDO and AMO does not change much. 1952, 1960, 1961, and 1966 were in cool phase of PDO and warm phase of AMO, while 2004 was in warm phase of PDO and AMO. So, how were the analog seasons like.

Analog Years (TS/H/MH ACE ACE/Storm)
1952 7/6/3 87 12.4
1960 7/4/2 88 12.6
1961 11/8/7 205 18.6
1966 11/7/3 145 13.2
2004 15/9/6 224 14.9

2013 Atlantic Hurricane Season analogs.

2013 Atlantic Hurricane Season analogs.

All were devastating seasons. 1952 had Hurricane Fox make landfall on Cuba as a Category 4 hurricane, making it one of the strongest to make landfall on the island nation. 1960 had a Unnamed Tropical Storm that dumped heavy rain that led to flooding in Texas after a dry spell. Later that season, Hurricane Donna ravaged the the Caribbeans and Florida. 1961 started late, but went into over drive with Carla ravaging the Texas Coast and Hattie ravaging Belize. 1966 had Alma hitting Cuba and Florida, while Inez was a long lived storm that devastated Caribbean, Cuba, Florida, and Mexico. 2004 had Charley, Frances, Ivan, and Jeanne ravaged Florida and Alabama within six weeks.

Let’s look at the statistics of the analog seasons.

10.2/6.8/4.2 149.8 14.4
10/7/4 149.8 14.4

11/7/3 145 13.2

Standard Deviation
3.3/1.9/2.2 63.9 2.6

Let’s look the overall Atlantic Hurricane Season statistics from 1870 to 2012.

Hurricane Season Average (1870-2012)
9.5/5.5/2.1 92.1 9.7
10/6/2/ 92.1 9.7

9/5/2 84.0 9.1

Standard Deviation
4.1/2.6/1.7 54.0 4.2

The analog years about average number of storms as it is within standard deviation. However, major hurricane, ACE, and ACE/Storm are above average. The analog years 1961 and 2004 have some of the highest ACE on record for the Atlantic basin. This shows it is not number of storms that makes it active, it is how many long lived, hurricanes, and major hurricanes are in a season.

This season may not see as many named storms from 2010 to 2012, but they could be powerful and long lived. Since some of the analog seasons started late like 1961 and 2004, while 1952 had an early start in February. The 2013 season could start late, but I think it will start in June.

However, since 2010, there have been 19 named storms due to the use of satellites. My thinking is the 2013 Atlantic Hurricane Season could have more named storms than in the analog years.

What is my prediction for this season?
14 to 20 named storms, likely 16 named storms
7 to 10 hurricanes, likely 9 hurricanes
3 to 6 major hurricanes with 5 major hurricanes
ACE is 170 to 230 with ACE likely of 180 to 220.

I think the 2013 Atlantic Hurricane Season is going to have 16 named storms, 9 hurricanes, and 5 major hurricanes with ACE of 200. This could be a very active season ahead. The number is subject to change at a later date. I do not expect any El Nino or La Nina to develop at this time. I think this season will most likely be a Neutral ENSO season because of cool PDO, which inhibits any potential El Nino development. This is on top of a warm AMO phase we are in, which started in 1995. Most forecast models show Neutral ENSO, neither La Nina or El Nino.

Let’s see how my May 2012 hurricane forecast compare to the actual 2012 season.

9 to 12 named storms, likely 11 named storms
3 to 6 hurricanes, likely 5 hurricanes
1 to 3 major hurricanes with 2 major hurricanes
ACE is 75 to 100 with ACE likely of 75 to 90.

2012 Actual Number
19 Named Storms
10 Hurricanes
2 Major Hurricanes
133 ACE

I was off with the number of storms, hurricanes, and ACE. One can call it a bust. However, I was right with the number of major hurricanes as there were two (Michael and Sandy). The reason I made the lower than normal 2012 hurricane season forecast is that I was expecting El Nino to develop, in which many forecast models forecasted. El Nino never developed in 2012 due to a unusually cool PDO in the Fall of 2012. The 2012 Atlantic Hurricane Season was largely Neutral phase of ENSO, which allowed a more active season.

Regardless of how many storms form and how late it starts, I think no one is going to be safe and there could be multiple major hurricanes making landfall. This could end the drought of major hurricanes making landfall on America, which started after Wilma in 2005. Again, it only takes one to be a devastating season, like in 1983 with Alicia, 1992 with Andrew, or 2012 with Sandy.


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