With the start of the Atlantic hurricane season on the horizon, folks at NOAA unveiled their seasonal outlook last Thursday morning in New York City.  The city itself has been the focal point of hurricane research after the devastation witnessed with Super-storm Sandy in October of 2012.  As a new meteorologist on the scene, this set-up is encouraging.  I love that the community is coming together with their common goal in mind, to help those who have been affected by the elements of nature.     

While we don’t usually see the unbearable storm surges or Cat 5 winds associated with some hurricanes that hit all along the coastline of the US, we can learn a few lessons from today.   1) Meteorologists and emergency management personnel are working around the clock to improve forecasts that everyday people depend on.  2)  The information in any forecast can help you prepare in any case, and it can help you alert family and friends who may be in the path of potentially hazardous weather.  And I think you’ll find this next quote pretty close to home! 

“We’re not here to scare you.  We’re here to prepare you.” – Chief Meteorologist Dave Dierks

Back to this week’s main topic…the upcoming hurricane season.

When does it start?  How long does it last?  When do most tropical systems form in the Atlantic?

This graphic below should answer all of those questions.


Source: National Oceanic and Atmospheric Administration

The first day of hurricane season is June 1st, but for folks in North Carolina (I being one of them at the time) the first day last year was June 7th when Tropical Storm Andrea hit.  While that was the only hard-hitting storm of the Atlantic season on the US, I wouldn’t recommend talking about a quiet tropical season to people in Raleigh, Durham and Chapel Hill, North Carolina 

We were expecting activity to then surge into August.  Why?  The peak activity seems to be from late August to early October, according to the graphic above.  Think about the most major hurricanes in recent history: Camille (August 1969), Andrew (August 1992), Dennis and Floyd (September 1999), Katrina (August 2005), Sandy (October 2012).  It’s not to say that ALL major tropical systems happen within this time frame, but the peak of the season is evident. 

So, what about this season?

For years now, Colorado State’s Bill Gray, NC State’s Lian Xie (Go Wolfpack!), and NOAA put out seasonal forecasts.  And in past years, these forecasts have been a very useful tool for forecasters in the US.  This got me thinking.  “Just how good are these forecasts? “ If the general public understands the amount of error in day 7 of the 7-Day Forecast, then how much error must there be in a 2-6 month outlook? 

For the most part, each institution gives a range of what to expect (ie. 12-15 named storms).  Since 2011, Colorado State has broken away from that trend and delivers an exact number.  To calculate the error in each forecast by scale, I have assigned the scale in this way:

                No Error: Number of observed storms appears within forecasted range.

                Very Low: Any number in the forecasted range is within one to two of what is observed.

                Low: Any number in the forecasted range is within three to four of what is observed.

                High: Any number in the forecasted range is within five to six of what is observed.

                Very High: Any number in the forecasted range is above six of what is observed.

NC State Error

Year

Named Storms Error

Hurricane Error

Major Hurricane Error

2010

None

Very Low

Very Low

2011

Low

None

Very Low

2012

Very High

Low

Very Low

2013

None

Very High

High

 

 Colorado State Error

Year

Named Storms Error

Hurricane Error

Major Hurricane Error

2010

Low

High

None

2011

Low

Very Low

Very Low

2012

Very High

High

None

2013

High

Very High

High

 

NOAA Error

Year

Named Storms Error

Hurricane Error

Major Hurricane Error

2010

High

Very Low

Very Low

2011

Very Low

Very Low

Very Low

2012

High

Low

Very Low

2013

None

High

High