More Spring 2011 Analogs

Looking at the analogs put out by Dr. William M. Gray and Dr. Philip J. Klotzbach, I took a look at what path they take. The analogs for 2011 posted are 1955, 1996, 1999, and 2008. Here is what the atmospheric and water conditions were based on winter and spring. Winter is from December to January, while spring is from March to May.

1955 (Winter)
ENSO=-10 Moderate La Nina
PDO=-6.1 Weak Negative
NAO=-8.7 Weak Negative
AO=-7.2 Weak Negative
PNA=-6.2 Weak Negative
AMO=+3.8 Neutral

1955 (Spring)
ENSO=-9 Weak La Nina
PDO=-14.8 Moderate Negative
NAO=-6 Weak Negative
AO=-3.8 Neutral
PNA=-9.3 Weak Negative
AMO=+12 Moderate Warm

1996 (Winter)
ENSO=-7 Weak La Nina
PDO=+5 Weak Positive
NAO=-15.7 Strong Negative
AO=-10.6 Moderate Negative
PNA=+2 Neutral
AMO=+2.5 Neutral

1996 (Spring)
ENSO=-3 Neutral
PDO=+15.5 Strong Positive
NAO=-18 Strong Negative
AO=-10.8 Moderate Negative
PNA=+2.1 Neutral
AMO=-1.2 Neutral

1999 (Winter)
ENSO=-14 Moderate La Nina
PDO=-4.7 Neutral
NAO=+17.3 Strong Positive
AO=+6.5 Weak Positive
PNA=-0.2 Neutral
AMO=+16.1 Strong Warm

1999 (Spring)
ENSO=-8 Weak La Nina
PDO=-4.7 Neutral
NAO=+2 Neutral
AO=-3.3 Neutral
PNA=+2.8 Neutral
AMO=+13 Moderate Warm

2008 (Winter)
ENSO=-14 Moderate La Nina
PDO=-7.8 Weak Negative
NAO=+9 Weak Positive
AO=+8.6 Weak Positive
PNA=+1.1 Neutral
AMO=+12.4 Moderate Warm

2008 (Spring)
ENSO=-8 Weak La Nina
PDO=-12 Moderate Negative
NAO=-11 Moderate Negative
AO=-3.6 Neutral
PNA=+0.1 Neutral
AMO=+16.2 Strong Warm

ENSO
1955, 1996, 1999, and 2008 had La Nina that was fading. In some cases they became Neutral or went back to La Nina again (1955 and 1999). The early 1950s and late 1990s had persistent La Nina.

PDO
The analog years were mostly in the cooler or neutral phase of Pacific Decadal Oscillaton. The exception was 1996 when it was in a warmer phase.

NAO
The North Atlantic Oscillation was all over the place, mostly negative NAO. 2008 had a positive to negative NAO.

AO
The Arctic Oscillation for the most part was in the negative to neutral. There were some positive AO, 1999 (winter) and 2008 (winter).

PNA
The Pacific/North America pattern was mostly in the negative to neutral pattern.

AMO
All were in warmer phase of the Atlantic Ocean and warmed up as the days get longer.

Now, let’s look at the path of tropical cyclones go in the analog years.

Notice that the Caribbean, especially Puerto Rico and Cuba, Carolinas, and Texas is at higher risk for landfall. In fact the East Coast is at higher risk for landfalls. Interestingly, Florida sees less landfalls. 1999 and 2008 were bad years for Texas, Bret made landfall 1999, while Dolly, Edouard, and Ike made landfall in 2008.

Keep in mind looking at analog years can help give us an idea what the upcoming hurricane season could be like in terms of how many storms form, path, and even landfall. They are many variables that influence formation, path, and landfall. Example, a tropical wave that comes off of Africa forms in the Atlantic and recurves to the northeast never making landfall. That is one reason why so many storms in 2010 did not hit land. On the other hand, a tropical wave moves and does not develop due to windshear and once over the Caribbean it develops into a hurricane and makes landfall, which would be the case in 2005. Many storms formed closer to land in 2005, while in 2010 most storms formed in the middle of Atlantic.

A storm that forms closer to land is more likely to make landfall than a storm that forms further from land. Reason, a tropical cyclone is more influenced by mid and upper air patterns, especially the deeper they get, which steer it either away or towards land. A tropical wave is less influenced by mid and upper air patterns.

This is all just what I think. I am not in any way suggesting that the 2011 season will resemble those analog years. Anything can change at any moment. As mentioned, I like to use history to predict the future. No season is going to be exactly the same.

Sources
ENSO After 1950
NOAA-ENSO Data

PDO
JISAO-PDO

NAO
UCAR-NAO

AO
NOAA-AO

PNA
NOAA-PNA

AMO
NOAA-AMO

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