Warm Atlantic Sea Temperatures suggest an active Hurricane Season

The sea surface temperatures in the tropical North Atlantic recorded the warmest ever April on record according to the UK Hadley Center. In a recent post by Dr. Jeff Masters (Wunderground) this does not bode well for the coming hurricane season[I]. “[/I][I]The three past seasons with record warm April SST anomalies all had abnormally high numbers of intense hurricanes. Past hurricane seasons that had high March SST anomalies include [COLOR=blue]1969 (0.90°C anomaly), 2005 (1.19°C anomaly), and 1958 (0.97°C anomaly). These three years had 5, 7, and 5 intense hurricanes, respectively. Just two intense hurricanes occur in an average year.”[/COLOR][/I]
Link to this blog

The 2009 season ended November 30 had only nine storms, including three hurricanes, and was the quietest since 1997 due in part to El Nino, the eastern Pacific warm water phenomenon that tends to suppress Atlantic hurricanes.
But Phil Klotzbach, lead forecaster with the Colorado State team – whose research is followed closely by energy and commodity markets – said El Nino was expected to dissipate fully by the start of this year’s storm season.
“The dissipating El Nino, along with the expected anomalously warm Atlantic ocean sea surface temperatures, will lead to favorable dynamic and thermodynamic conditions for hurricane formation and intensification,” said Klotzbach.
[B]The Colorado State University team has repeatedly cautioned that extended-range forecasts for hurricane activity are imprecise and can often miss the mark.[/B]
The university team originally expected the 2009 season to produce 14 tropical cyclones, of which seven would become hurricanes. But the season, which ended on November 30 and was the quietest since 1997, had only nine storms, including three hurricanes.

More detailed report: http://hurricane.atmos.colostate.edu/forecasts/2010/april2010/apr2010.pdf

Personally, I would take anything regarding climate info from NASA with a grain of salt. They have been proven wrong countless times.

Several factors seem to be coming together to make this a very interesting season.

  1. Sea surface temperatures in the tropical North Atlantic were at or near record high levels in March and April. Warm ocean water provides the energy to sustain hurricanes.

  2. Currently the El Nino has dissipated and is already in the neutral phase. Forecasts suggest that the [B]El Niño-Southern Oscillation[/B] or [B]ENSO[/B] could go to a weak La Nina state by the main hurricane season. Hurricane activity is highest during neutral and weak La Nina conditions. (Last season tropical storm activity was reduced due to increased wind shear caused by an active El Nino event).

  3. The NAO (North Atlantic Oscillation) continues to be negative which is an indicator that the Azores to Bermuda high pressure ridge is weaker than normal which in turn reduces the intensity of the trade winds. Lower trade winds minimize wind shear and also allow for less cold water upwelling. Low wind shear and warm water are favorable for tropical development. Also a negative NAO tends to be correlated with hurricanes that track farther westward thus more likely to impact the US.