NOAA Predicts "Active" Hurricane Season

Oh goody...

2013 Atlantic Hurricane Season Outlook: Summary

NOAA’s 2013 Atlantic Hurricane Season Outlook indicates that an above-normal season is most likely, with the possibility that the season could be very active. The outlook calls for a 70% chance of an above-normal season, a 25% chance of a near-normal season, and only a 5% chance of a below-normal season. See NOAA definitions of above-, near-, and below-normal seasons, which have been slightly modified from previous years. The Atlantic hurricane region includes the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico.

The 2013 seasonal hurricane outlook reflects a combination of climate factors that have historically produced above-normal Atlantic hurricane seasons. The three main climate factors for this outlook are:

1. The ongoing set of atmospheric conditions that have been producing increased Atlantic hurricane activity since 1995, which includes
2. An expected continuation of above-average sea surface temperatures (SSTs) across the tropical Atlantic Ocean and Caribbean Sea, and
3. A likely continuation of ENSO-neutral conditions (i.e., no El Niño or La Niña); meaning El Niño is not expected to develop and suppress the hurricane season.

This combination of climate factors historically produces above-normal Atlantic hurricane seasons. The 2013 hurricane season could see activity comparable to some of the very active seasons since 1995.

Based on the current and expected conditions, combined with model forecasts, we estimate a 70% probability for each of the following ranges of activity during 2013:

13-20 Named Storms
7-11 Hurricanes
3-6 Major Hurricanes
Accumulated Cyclone Energy (ACE) range of 120%-205%

The seasonal activity is expected to fall within these ranges in 70% of seasons with similar climate conditions and uncertainties to those expected this year. These ranges do not represent the total possible ranges of activity seen in past similar years.

Note that the expected ranges are centered well above the official NHC 1981-2010 seasonal averages of 12 named storms, 6 hurricanes, and 3 major hurricanes.

This Atlantic hurricane season outlook will be updated in early August, which coincides with the onset of the peak months of the hurricane season.

A nice safe forecast.  If they've overestimated the number and severity of storms, nobody will be disappointed when they fail to meet expectations, and they'll have to be fairly severe to be outside the range predicted.

So, historically speaking, how good are their forecasts?  Not very, about as good as a coin toss...

An NBC Miami review of nearly a decade of pre-season predictions of hurricane season shows the two major predicting institutions are right about half the time. In some categories, they fail even more frequently.

Imagine how difficult it must be to predict something so intricate, so constantly transforming as a storm four months in advance. Yet our well-being depends on such factors as wind shear, sea surface temperatures, and pressure systems half a world away.

And this year looks busy. "indeed, we are looking for an 85% chance of above normal activity,” said Jack Beven of the National Hurricane Center. “The forecast is anywhere from 14 to 23 named tropical storms, of which 8 to 14 are forecast to become hurricanes, and 3 to 7 are forecast to be major hurricanes."

The National Hurricane Center, also called NOAA Weather, makes its pre-season predictions using a range. It offers wiggle room in the prediction. This year, 14 to 23 storms, is the widest range in a decade.

On the other hand, Dr. Bill Gray of Colorado State University predicts an exact number. Not a range.

Still, predicting these hurricanes and storms is imperfect to be sure, as our review of the success of those pre-season predictions since 2001.

First, in predicting named storms, NOAA has fallen within its range 5 times in 9 years. Dr. Gray has hit his number just once. But if granted a range like NOAA uses, Dr. Gray has been right 5 times also in 9 years.

So don't sweat the forecast. Do your best to be prepared, and wait to find out