2014 Atlantic hurricane season activity forecast to be near-normal

by Artemis on December 17, 2013

The first quantitative forecast for the 2014 Atlantic tropical storm and hurricane season has been published by Tropical Storm Risk (TSR). The early forecast calls for Atlantic hurricane season activity to be near-normal during 2014.

As with any early forecast of tropical storm and hurricane activity in the Atlantic there is considerable uncertainty associated with the forecast from Tropical Storm Risk (TSR). TSR is the first this year to put numbers to the amount of tropical storms and hurricanes it expects in 2014. The Colorado State University forecasting team has published a qualitative discussion of forecast potential, but no longer forecasts the number of storms this far out.

TSR forecast 14 named tropical storms, 6 hurricanes and 3 major (Category 3+) hurricanes between the months of June and November in 2014. This is very close to the long-term average since 1950, but around 20% under the average from 2004 to 2013. The average to compare this with is 11 named storms, 6 hurricanes and 3 major hurricanes, so not much different in terms of loss potential to the insurance and reinsurance industry.

TSR cites two primary factors which led it to a forecast for a near-normal, to slightly above normal, Atlantic hurricane season in 2014. First, model projections indicate that trade winds over the Caribbean Sea and the tropical North Atlantic will be a little stronger than normal from July to September, which could help suppress cyclogenesis. These slightly higher trade winds coincide with the expectation of weak positive ENSO (El Niño) conditions in August and September 2014. This could help to suppress activity in the tropical Atlantic.

Secondly, there is a long-range forecast for slightly warmer than normal sea surface temperatures in the Atlantic Ocean’s main development region during the peak months of August and September. TSR said that this should have a small enhancing effect on activity, so offsetting the tradewinds and El Niño a little.

The Colorado State University tropical meteorology team do not give forecasts for the number of storms this early on anymore. However they do give a qualitative forecast of the potential for hurricane activity in the 2014 Atlantic season.

Two factors will affect the amount of activity in the 2014 hurricane season, according to the Colorado State researchers, the strength of Atlantic thermohaline circulation and the phase of ENSO (El Niño or La Nina). Thermohaline circulation refers to the ocean circulation that occurs due to water density and freshwater content of seawater.

The researchers believe that the level of hurricane activity in the Atlantic in 2014 will be driven by the strength of this circulation and whether an El Niño occurs in 2014. The researchers give four outcomes based on their analysis of the likelihood of these factors occurring and give a probability for each scenario.

  1. THC circulation becomes unusually strong in 2014 and no El Niño event occurs (resulting in a seasonal average net tropical cyclone (NTC) activity of ~ 180) – 15% chance.
  2. THC continues in the above-average condition it has been in since 1995 and no El Niño develops (NTC ~ 140) – 35% chance.
  3. THC continues in above-average condition it has been in since 1995 with the development of a significant El Niño (NTC ~ 75) – 40% chance.
  4. THC becomes weaker and there is the development of a significant El Niño (NTC ~ 40) – 10% chance.

Net tropical cyclone activity (NTC) is a similar kind of measure to accumulated cyclone energy (ACE), so gives an approximation of the amount of activity in the season based on a numerical scale. The researchers explain that the NTC’s given above can typically be expected to translate into activity as below.

  • 180 NTC – 14-17 named storms, 9-11 hurricanes, 4-5 major hurricanes
  • 140 NTC – 12-15 named storms, 7-9 hurricanes, 3-4 major hurricanes
  • 75 NTC – 8-11 named storms, 3-5 hurricanes, 1-2 major hurricanes
  • 40 NTC – 5-7 named storms, 2-3 hurricanes, 0-1 major hurricanes

So, with the researchers suggesting that there will be somewhere between 75 and 140 NTC of activity in the 2014 Atlantic hurricane season that would suggest somewhere between 8-15 named storms, 3-9 hurricanes and 1-4 major hurricanes.

It should be noted that all forecasters were a distance out with their forecasts for this years hurricane season, both of these groups of forecasters said the season would be above average in terms of activity and it actually turned out to be below average. So long-range hurricane forecasts do need to be taken as an approximation of the potential for activity in the forthcoming season, rather than a guide to the number of storms and hurricanes to expect in 2014.

We will update you as we move through 2014 and more forecasts for Atlantic hurricane season activity are released. We will also have our 2014 Atlantic hurricane season page up and running and will begin to collect information on it as we approach the season. Make sure to bookmark the page so you can refer to it when the season begins.

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