For the past 48 hours, it seems as if every media outlet in the country has been focused on the path of Hurricane Irene. Governors are declaring states of emergencies, NYC has shut down its mass transit system, warning residents to run for their lives. So is this media hype an overreaction, or will Irene really pack the punch that we are being warned of?
Despite her massive size, Hurricane Irene is a very ordinary hurricane taking a rare path up the megalopolis. I’m one of millions of American’s glued to the TV for the wall-to-wall coverage. The reason Irene is capturing this massive media attention is because of her track, not her characteristics.
Irene is currently a weak category one hurricane, as you may know, she just cleared Outer Banks of North Carolina, in a very unimpressive manner. Irene, unlike many Atlantic hurricanes, is taking a rare course; a course that will affect millions of American’s in the metropolitan areas of Washington D.C., Baltimore, Philadelphia, New York, Providence and Boston.
Irene is moving relatively slowly for a hurricane located so far to the north (the westerlies in the higher latitudes will up the speed fairly soon). Newark, JFK and La Guardia are all closed and so is mass transit in NYC, for the first time in history. Mayor Bloomberg shut down the subways hours ahead the storm, making some wonder: was it too soon? Bloomberg has warned citizens in NYC living above the 10th floor in any building that their windows could shatter due to strong winds.
Is the warning an overreaction? Consider this: NYC routinely gets Nor’Easters where wind velocities can be nearly as strong as what is predicted to come with Irene. The Christmas Blizzard of 2010 contained sustained winds of 40-50 mph and wind gusts to 60 mph. These wind velocities are only slightly lower than the winds I expect the city to see with Irene, but I am not aware of any similar “window warnings” ever issued for a winter blizzard.
As I went into work early Friday morning we, in Portland, were facing an unexpected round of severe weather, so I spent most of the morning staying on top of our local weather. As our storms moved east of the Cascades I was able to pull up the latest hurricane models, a familiar practice since I worked in South Florida during the historic year of 2005 and was part of the wall-to-wall coverage of Kartina, Rita, and of course Wilma. In 2005 there were so many storms that we had to adopt the Greek alphabet since the list of potential named storms ran out. I learned more than I cared to know about Hurricane’s during 2005 – more about Hurricane’s by covering them than by any Meteorology course I had ever taken in college.
When I assessed the latest models of Irene and checked her position, strength and track, the first thing I realized was that she had just battered the Bahamas and was now a category 2 storm. Irene would intensify no more and would in fact weaken as she moved into the relatively cooler waters of the Atlantic. Keep in mind, the Gulf Stream is a warm ocean current that extends very far to the north along the East Coast; the only reason hurricanes can even be seen in places like the Carolina’s and up into New England.
Many of my co-workers here in Portland, Oregon have asked why we don’t see hurricanes here in the Pacific Northwest. My response: we frequently get winter winds at the Oregon Coast 50 mph stronger than what NYC will see when Irene hits. On the Pacific Coast of the U.S., by the time you get to the U.S./Mexico border, water temperatures are only in the lower 70s. Hurricane’s are born by massive amounts of latent heat in the ocean where water temperatures are 80 degrees or higher. In fact, 80 degrees is almost marginal and 82 degrees can spawn a much more powerful hurricane.
An example of this was Katrina in 2005. Katrina passed over Miami-Dade and Broward counties in South Florida as a category 1 hurricane. As it entered the Gulf of Mexico it gained strength in the shallower waters which were much warmer and aided by a loop current which blew the storm into a massive category 5 hurricane.
Irene is definitely a large hurricane but is by no means a Katrina, a Hugo or an Isabel. It will continue to weaken as it enters the cooler waters and as it interacts with the friction of the land-masses. We learn through history and really the last major hurricane to impact the Northeast was the Great Hurricane of 1938 – a massive category 5 hurricane that made landfall on Long Island as a category 3. The path was farther to the East and not directly over NYC, but the impacts were much greater than Irene will ever be. Let us also consider Hurricane Gloria in 1985. Its track was almost identical to Irene and was a much more powerful storm. Gloria made a second landfall in Long Island as a strong category 2 hurricane. Wind velocities from Gloria were 85 mph and due to its forward speed of nearly 35 mph, wind gusts were recorded up to 115 mph, or the equivalent of a category 3 hurricane. Damage was extensive with Gloria and its legacy will be remembered much more than Irene.
I believe much of the attention is being focused on the exact track over NYC rather than the reality of the possible impacts. Storm surge and heavy rains will be the biggest impact – especially due to recent record rainfall. Beach erosion and rip-currents are inevitable. Weak tornadoes are also possible. There will be power outages and some downed trees. Of course timing is paramount as well. If Irene rolls into New York at high tide, the storm surge will cause major damage to the immediate coast. Irene will be a costly hurricane since it will affect millions of people in densely populated areas – maybe one of the costliest hurricanes ever. But windows will not be shattered in the big cities and I believe millions of American’s by Monday will be left wondering why all the hype?
This hype concerns me. Right now we are watching an ordinary category 1 hurricane batter the coast of North Carolina. The storm will arrive in NYC as Tropical Storm Irene, not Hurricane Irene. It’s my opinion that it is the unique track of Irene, not the storm itself, headed directly to NYC that has caused so much concern.
What happens when a 920 millibar category 5 batters the North Carolina coast in the near future..and hits NYC as a category 3? If the reaction we are seeing with Irene proves to be an “overreaction” will east coast residents ever heed warnings to evacuate again? Are we crying wolf too soon?