Posted: 5:30 pm Tuesday, June 5th, 2018
By Kirk Mellish
Now that we are in June tropical cyclone season is here, generally just called “hurricane season” running from June through November reaching a peak September 10th:
The most active season was 2005, during which 28 tropical cyclones formed, of which a record 15 became hurricanes. The least active season was 1914, with only one known tropical cyclone developing during that year.
We are in a transition in the Pacific Ocean pattern to an expected El Nino. El Nino usually acts to suppress the tropical cyclone season. However, its predictability in the spring is not very good. Therefore, the speed at which the El Nino comes and how strong it will be and what type are still uncertain. This adds more than usual uncertainty to the hurricane season forecast for now. So there is a greater than usual RANGE in predictions.
Generally speaking the outlook is for a less active season than last year, and a season that is in the ballpark of average or a little below-average in activity.
A “canonical” or basin-wide traditional type El Nino is more likely to limit tropical cyclone production, whereas a central Pacific based “Modoki El Nino” has less of a limiting influence. We should get more clarification on what to expect later this month and beyond.
At this point neutral conditions or a weak El Nino are expected during the fall peak of the season.
The AUSTRALIAN METEOROLOGY BUREAU however keeps it neutral through summer:
The Atlantic Ocean temperatures and those of the Caribbean Sea are also obviously important in storm genesis. The main breeding ground is featuring cooler than normal Atlantic sea-surface temperatures which is a negative factor. There are also indicators for greater than normal wind shear and Saharan dust and a stronger than usual subtropical Atlantic high pressure which are also negative influences.
2018 TROPICAL STORM-HURRICANE NAMES:
I spy with my little eye the name Kirk.
NOAA/NWS is not the only organization to take a stab at forecasting the number of tropical storms and hurricanes that will form. Universities and private companies do as well.
Keep in mind that few even try to predict the most likely zones for them to go once they form until a storm actually exists. That is because so far such outlooks have demonstrated little skill.
On the other hand projections of the total number of storms have shown modest skill. Yet the numbers don’t tell us if many, a few or none will hit land. That takes short-term forecasts not long-range “seasonal” outlooks like these.
Below is a summary of all the forecasts publicly issued.
Charts are courtesy of the Barcelona Supercomputing Center and Colorado State University.
CONSENSUS FOR NAMED TROPICAL SYSTEMS (13):
CONSENSUS FORECAST is for an average season with (6) HURRICANES:
CONSENSUS FORECAST FOR MAJOR HURRICANES (3):
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