KNOXVILLE, Tenn. (WVLT) -- This week’s Ask Heather comes from Scott Crass. He wanted to know how the number of hurricanes are predicted each year, with the season outlook.
Hurricane season in the Atlantic starts June 1 and runs through the end of November, and generally picks up around August.
The outlook is issued every year in May and then it will be updated some time in early August by the NOAA Climate Prediction Center, which works with the National Hurricane Center. There are also several major research groups that put out their hurricane season outlooks.
We've had one named storm so far this year, with Category 2 Arthur, which developed July 1.
This year, the NOAA outlook is for a near-normal or below normal Atlantic hurricane season, which is 8 to 13 named storms, 3 to 6 hurricanes, 1 to 2 of which could be major. The other researchers had similar results.
It’s based on predictions of large-scale climate factors that are known to influence seasonal hurricane activity.
Some key indicators:
1. The expected development of El Niño, which is warmer than normal temperatures in the Pacific. This tends to suppress hurricane activity in the East, while making for a rainier season in the West.
2. Expected near or below average Sea Surface Temperatures (SSTs)
3. Atmospheric conditions in the Main Development Region (MDR), the warm, deep area of the Atlantic Ocean. This focuses on vertical motion and wind shear
Uncertainties come down to the timing and strength of El Niño, plus limited confidence in model forecasts for Sea Surface Temperatures.
Also, just recently, the National Center for Atmospheric Research (NCAR) finished a study that shows even the slightest change in the atmosphere can majorly shift the outcome of the hurricane season.
If you have a question about the weather, just Ask Heather.
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