Hurricane Seasons and El Niño

[donsutherland1]

The impact of the unfolding El Niño on the current hurricane season and the 2005 one arose at another message board. Overall, the arrival of the 2004 El Niño comes too late to have a significant adverse impact on the ongoing season. Moreover, it is a weak El Niño and could be gone by next season.

Also, one should not automatically assume that every El Niño means an inactive season.

With respect to the relationship between El Niño and hurricane seasons, here are some relationships using data from 1950-2003:

Averages:
(Named Storms-Hurricanes-Major Hurricanes)

El Niño: 8.9; 4.8; 1.8
No El Niño: 10.3; 6.5; 2.9

El Niño-East QBO: 6.9; 4.1; 1.3
El Niño-West QBO: 11.4; 5.7; 2.3

MEI +1.00 or above: 6.4; 3.1; 1.0
MEI +1.00 or above-East QBO: 5.5; 3.0; 0.8

MEI < +1.00: 12.1; 6.9; 2.6
MEI < +1.00-West QBO: 14.3; 7.5; 3.5

Notes:
• For seasons with an El Niño for the July-September period
• Averages for the MEI and QBO are for the May-November period

Conclusions:
• In general, hurricane seasons with an El Niño during the July-September period are less active than those without an El Niño during this period.

• El Niño seasons with an East QBO are generally quiet seasons

• El Niño seasons with a West QBO are generally active seasons

• Strong El Niño seasons (using the MEI as a measure) with an East QBO are very quiet

• Weak El Niño seasons (using the MEI as a measure) with a West QBO are very active

[cswitwer]

Much appreciated!

[EarthStormFire]

Remember after El Nino, you have La Nina, and La Nina years means more hurricanes than normal a lot more than normal

[AussieMark]

not always.

El Nino in 2002

no La Nina formed after that

[donsutherland1]

Long-range ENSO predictions point to the possibility of a neutral summer in 2005.

[The RAT]

I'll vote for a "normal" if that might mean dull too!!!

[tronbunny]

Long-range ENSO predictions point to the possibility of a neutral summer in 2005.

I'll take anything less than "active"

[donsutherland1]

Just a quick note, when I refer to a "neutral" summer, I'm referring to a neutral ENSO as opposed to El Niño or La Niña. I am not suggesting that the 2005 season will be active or inactive.

[Skywatch_NC]

I've heard over the next 10 to 15 years or so...that the tropics are supposed to be more active (let's take this year for ie.) since a lull from the early/mid 1990's.

Comments?

Eric