Colorado State University (CSU) has issued their initial 2019 Seasonal Atlantic Hurricane Forecast. Keep in mind, hurricanes prefer warm ocean temperatures and weak wind shear to both form, intensify and thrive.
Overall, here are the main takeaways:
CSU forecasts a slightly below normal season
13 named storms (12.1 on average)
5 hurricanes (6.4 on average)
2 major hurricanes (2.7 on average)
The reasoning behind the present forecast:
Cooler North Atlantic and tropical Atlantic sea surface temperatures (SST’s) along with warmer SST’s off the East Coast indicate the The Atlantic Multi-decadal Oscillation (AMO), which has been in a positive phase since 1995, may be shifting to the negative (cool) phase.
Climatologically, fewer tropical cyclones form during the negative AMO phases, which are characterized by cooler SST’s in the main development region for tropical cyclones.
AMO phases generally last between 25 and 40 years. If the AMO indeed is shifting to the negative phase, we could see future seasons of below-normal Atlantic tropical cyclone activity.
A weak El Nino which has been in place is forecast to persist or intensify
El Nino tends to suppress hurricane activity in the western Atlantic by increasing wind shear.
CSU did note that there is little certainty what the tropical Atlantic SST’s will look like during the peak of hurricane season (August-October) so it may be possible that the AMO is not yet shifting to the negative phase.
NOAA typically issues their official hurricane forecast at the end of May.
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