Fri August 23, 2013
Hurricane Season A Bust? Don't Be So Sure
Originally published on Fri August 23, 2013 1:55 pm
Back in May, several independent forecast groups predicted an especially active Atlantic hurricane season this year. But with August drawing to a close, we've yet to see a single one.
Despite being hurricane-free so far, as we reported earlier this month, the National Oceanic and Atmospheric Administration is sticking to its forecast that warned of between seven and 11 hurricanes from the beginning of June to the end of November.
But in case you should think (or hope) that the 2013 hurricane season is a bust, Brian McNoldy, a senior researcher at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, has done some potentially sobering math: Writing for The Washington Post's Capital Weather Gang blog, McNoldy points out that while it's somewhat unusual to have no hurricanes this late in the season, it's by no means unprecedented: It happened in 1984, 2001 and 2002.
McNoldy quotes forecaster Phil Klotzbach at Colorado State University as saying that if you crunch the data back to 1960 and add in seasons where there were hurricanes in June and/or July, but none in August, you get four additional years: 1961, 1982, 1988 and 1997.
"1961 is an especially interesting year, in that August had no tropical cyclones and followed that up with the most active September on record with four major (Category 3-5) hurricanes forming! On the other hand, 1982 and 1997 remained quiet throughout the season."
So, what's the track record for pre-season hurricane predictions?
Two forecasters, Klotzbach and colleague Bill Gray, also at Colorado State University, have done pretty well, and in the years when they were off, it tended to be an underestimate on the number of hurricanes, according to Rick Grow, writing in April for the Capital Weather Gang:
"Eleven of Colorado State's 18 forecasts have come within three hurricanes of nailing the seasonal total and, on four occasions, they have only missed the cumulative number by one. They hit the mark in 2008. ... Of course, Gray and Klotzbach posted a few wayward forecasts as well: for 1995 (a five-storm underestimate), 2005 (undershot the total by eight) and in 2012 (fell short by six hurricanes)."