NHC increases hurricane forecast lead times

By: Dr. Jeff Masters , 7:27 PM GMT on January 05, 2010

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The National Hurricane Center (NHC) announced today that beginning with the 2010 hurricane season, their hurricane and tropical storm watches and warnings for the U.S. coast will be extended in time by an additional 12 hours. Warnings will now be issued 36 hours in advance instead of 24 hours, and watches will be issued 48 hours in advance, instead of 36 hours. The increase in lead time for watches and warnings has been made possible by the tremendous improvement in hurricane track forecasts, which have improved by over 50% in the past twenty years (Figure 1). "With increases in population and infrastructure along vulnerable U.S. coastlines, emergency managers need more lead time in order to make life-saving decisions regarding evacuations", said Bill Read, director of NOAA's National Hurricane Center, in today's press release.


Figure 1. Average track errors for NHC Atlantic tropical storm and hurricane forecasts issued between 1990 - 2008. Track errors have improved by over 50% in the past 20 years. Image credit: National Hurricane Center.

Commentary
NHC has been debating for a number of years how best to "invest" the gains accrued from the steady improvement in hurricane track forecasts. One obvious savings from these better hurricane forecasts has come from the reduced evacuation costs. When a hurricane warning is issued 24 hours before the expected arrival of hurricane-force winds at the coast, it costs approximately $1 million to evacuate each mile of U.S. coast warned (Aberson et al., 2006). This number will be higher for more densely populated areas of the coast, such as Miami, and may be a factor of six lower for the North Carolina coast (Whitehead, 2003). According to a 2007 presentation at the 61st Interdepartmental Hurricane Conference, the length of coast warned decreased significantly in the past decade. During the decade of the 1990s, the average length of a hurricane warning was 455 miles, but that fell to just 335 miles between 2000 - 2006. Thus, an average of 120 fewer miles of coast were warned, at an average savings of $120 million per hurricane warning issuance. During this period, 17 storms requiring 25 hurricane warnings occurred. If the costs of coastal evacuations are indeed $1 million per mile, the improved hurricane forecasts between 2000 - 2006 resulted in savings of $3 billion compared to what the forecasts of the 1990s would have cost.

However, the new increased lead times for hurricane watches and warnings will lead to an increase in the length of coast warned, due to the higher uncertainties in hurricane tracks at longer forecast lead times. Between 2004 - 2008, approximately 25% of the coast that was placed under a hurricane warning actually received hurricane force winds; this percentage was 20% for areas placed under a hurricane watch. These percentages will decline with the new increased watch and warning lead times, costing money in unnecessary evacuations, and leading to increased complacency in the warned population due to too much "crying wolf".

Balanced against these increased costs is the potential disastrous loss of life should a hurricane hit an unprepared, heavily populated shoreline. With the U.S. population continuing to increase rapidly in coastal regions, the time needed to evacuate vulnerable populated regions is increasing. For example, evacuation times for the major urban areas of Texas are 28 - 34 hours for a major hurricane. Though the costs of overwarning the coast is significant, the savings in both human lives and dollars from increased warning times should outweigh these costs. In the 2002 book, Hurricane: Coping With Disaster, Dr. Hugh Willoughby, former director of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Marine Laboratory, analyzed hurricane death statistics. In 1950, about 70 U.S. residents died per year in hurricanes. In the 50 years since, the coastal population expanded by a factor of 3.2, so if we were managing the hurricane problem the way we did in 1950, we would be losing about 220 people a year. The long-term average is still about twenty per year, not including the deaths due to the levee failures during Katrina. That means we're preventing about 200 deaths per year compared with 1950. How much are these saved lives worth? A life, is, of course, priceless, but in the cold world of economics, the value of life-saving scientific research and government regulations is estimated using statistics of what people are willing to pay to avoid certain risks, and what extra money employers pay their workers to take on additional risks. This data comes primarily from payroll statistics, but opinion surveys also play a role. In 2004, the Environmental Protection Agency (EPA) valued an American life at $8 million. EPA cut the value of a life by 8% that year, and a further 3% in May 2008, making the economic value of a life $6.9 million in today's dollars. The Department of Transportation gives a lower figure of a life as being worth $5.8 million. Using this number implies a savings of about $1.2 billion per year for the 200 lives saved per year by better hurricane warnings and evacuations. Today's decision by NHC to increase warning times should continue this trend of saving lives, which will also provide considerable monetary benefit. Despite the increased costs and dangers of "crying wolf" too often due to overwarning the coast, I believe that the double value of saving lives--for both the intrinsic and monetary value of a human life--makes NHC's move of increasing warning and watch times the right call.

References
Whitehead, J.C., 2003: "One million dollars per mile? The opportunity costs of Hurricane evacuation", Ocean and Coastal Management 46, 1069.

I'll have a new post on Thursday or Friday.

Jeff Masters

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Quoting Jeff9641:


I know they said Key West 62 and I thought they said you 63 maybe at the airport because the airport is just a mile or 2 away from the sea. by the way I love Nassua. I go there several times a year for vacation.
I think it was colder in Key West than here all day. Amazing! As for the airport location, it's impossible to be more than 4 miles away from the sea anywhere on New Providence; the island is only 7 miles wide at its widest point .... lol. But the ocean is only about a mile north at the most. Almost as important, the island's largest lake, Killarney, is immediately adjacent to the airport, which is actually built on the lake's western floodplain.

Glad to know u enjoy your visits here. It's expensive to live here, but I wouldn't trade it for most other places in the world.
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Quoting FLPandhandleJG:


I thought that the lake was dry or something.. b/c i heard a year or 2 ago with the drought that florida had with all the brush and wild fires that it was drying up.. did mother nature saved it.. LOL
chi

Ha, ha, ha!! Good try. Lake Okeechobee is still full of water!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting TampaSpin:


Its full bank now....not a problem.


Okay.. just making for sure.. so u think L will for near the GOM or?
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting Bordonaro:


Or do you like this one better??



haha looks good!
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Darwin Northern Territory Australia
Link
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hmmm.. look at that little bugger staying alive the SW near the jet stream or already in.. thats heading towards the gulf right or ?
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting AussieStorm:

Have you watched the movie 2012?
BTW I hope that never happens


Sci-Fi meets Lord of the Flies meets Gilligan's Island. The poles shift and it's sianara baby...holy cow batman, we've got a situation. That's alarmist.
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Quoting tornadodude:


haha thanks!


Or do you like this one better??


Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Jeff9641:
TWC said Tampa could get 1 to 2" of snow. This can't be true! Right!

Wait. They were discussing a forecast?!? Didn't know they did that anymore...
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Quoting FLPandhandleJG:


I thought that the lake was dry or something.. b/c i heard a year or 2 ago with the drought that florida had with all the brush and wild fires that it was drying up.. did mother nature saved it.. LOL


Its full bank now....not a problem.
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Quoting Grothar:
Anyone consider the possibility of lake effect snow from Lake Okeechobee?? That would be a sight.

Cannot verify, but it looked like NOLA (just east, anyway) got the tiniest bit of lake effect flurries from Lake Pontchartrain early this morning. Just some hints on radar. Usually beyond the clutter area for clear-weather radar VCP, but who knows?
I somewhat doubt it...
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aussie...I'm not sure...
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Quoting Bordonaro:


Funny, and guess where the snow would fall, with a NW wind? Answer: Miami!!


I thought that the lake was dry or something.. b/c i heard a year or 2 ago with the drought that florida had with all the brush and wild fires that it was drying up.. did mother nature saved it.. LOL
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting Grothar:


Hey, you can always call me. I am there all the time. I wouldn't mind giving you a lift, just don't talk about GW or the trip would seem longer. LOL

The trip seems very long as it is.

Work sends me there at least once a year (and pays the bills). I'll be there for a few days around Valentine's Day next month.

You know what stinks? I've been there about a dozen times, and worked every waking moment every time. All I saw there was the inside of a hotel room, the inside of a couple of restaurants, the inside of cabs, and the inside of the convention center. Got to figure out a way to do something fun for 10 minutes this year.
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Quoting Jeff9641:


They were just making fun of the Canadian Model because it was throwing alot of moisture in cold air across north and cental FL. I expect all rain here but fun to talk about.


Not what happened 10 years ago.. Certainly could happen again, I'm watching it, maybe a surprise freak snow event in Northern Florida. CMC is repeating the 1989 Florida Christmas Snowstorm. You got cold air with moisture, it's a slim possibility.
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Quoting Jeff9641:
People are going crazy on TV here in orlando saying that we could have accumalating snow on Saturday! What!! The Canadan Model has moderate to heavy snow across C and N FL of Saturday.


Hmm I wonder if the CMC is biased towards snow :)
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Quoting Bordonaro:


They forgot the penguin and the polar bear!!




haha thanks!
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Quoting Jeff9641:
TWC said Tampa could get 1 to 2" of snow. This can't be true! Right!

Never will happen! What met said that?
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Quoting Grothar:
Anyone consider the possibility of lake effect snow from Lake Okeechobee?? That would be a sight.


Funny, and guess where the snow would fall, with a NW wind? Answer: Miami!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting TampaSpin:


Lake effect snow occurs when a cold air rushes over open water that is not frozen. The open water is warmer than the air above causing Lift and instablitity just like a thunderstorm in a sense therefore Snow because of the cold temps aloft and at surface.

Ahh, yes, but (always one of those, right?). Yes, but is the lift enough to overcome a steep inversion? This one is huge (for Tampa):



Another yes but: Yes, but is the lift and condensation/freezing still going to happen when saturated air at the surface would not be saturated aloft? It would take a lot of evaporative cooling aloft to cool all of the air above down to temps that no longer maintain a vapor of any moisture that rises and starts out with the surface temps.
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Quoting Jeff9641:
TWC said Tampa could get 1 to 2" of snow. This can't be true! Right!


no not the TWC.. lol could b possible, that would b cool if ya'll want snow or not.. ;)
Some reason i think the panhandle is going to miss the snow.. its like a halo here lol
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Member Since: July 15, 2006 Posts: 171 Comments: 53809
Looks like the timing of the front during the nite for Florida with the extra nite time cooling and the front coming through is perfect timing for Snow into Central Florida very possible.....look at the 7pm map forecast...

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Jeff, is that Nassau, like Bahamas? Because if so, we actually got up to 70 around 1 today (very briefly).
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I believe theres goin to b alot of moisture building up tomorrow.. it has a chance to build into the L that we r waiting for if it does..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting Jeff9641:
I hope we don't get snow in Orlando. I really want the warm air back. Nassua's high was 63 today Key West 62 and the low there is forecast to hit 47. WOW!!!


I've been watching the CMC, noticing the GFS hinting towards the CMC solution. I dunno where you saw METS saying heavy snow Saturday, would love to see that link if you have if. I live in Flagler County, North/Central Florida.
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Anyone consider the possibility of lake effect snow from Lake Okeechobee?? That would be a sight.
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Quoting tornadodude:


They forgot the penguin and the polar bear!!


Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting HTV:
Can I step in here and comment on the weather and the chili discussion? First I think we can all agree it's cold. Now for more important matters, chili ain't chili if it's got chicken in it. As a native Texan who grew up in New Mexico and then again in Texas real chili contains beef, venison or road kill. I guarantee there ain't been anybody go out of their way to run over a chicken to add to a pot of chili.


Thank you ;)
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Quoting atmoaggie:

Boy does that make me feel better about the 75 dollar cab fare...


Hey, you can always call me. I am there all the time. I wouldn't mind giving you a lift, just don't talk about GW or the trip would seem longer. LOL
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Quoting TampaSpin:


Definitely so...that warmer air from the Lake caused a lot more lift .....hence alot more snow as long a the Air was very cold.


well my mets and noaa saying rain/snow.. if there is goin to be snow, that it will b after 9pm.. b/c they expecting warmer temperatures through most of the day.. but i think it will b lil colder than expected.. I believe there will sum moisture til early friday afternoon too.. just my opinion..
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Quoting presslord:
it sounds like fun aussie...and the Grand Prize is a years' worth of serious braggin' rights...

Is it in rounds or just a cumulative points system.
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Weel, me hearties, methinks I'll have a spot of tea, then jump into me jammies and thence into me wee bed....

Ta-Ra!
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Quoting Jeff9641:


Some of the biggest lake effect events occured when the lake temps were in the 50s. Example Oct. 2007 or 2008 Buffalo had 21" in 24 hours.


Definitely so...that warmer air from the Lake caused a lot more lift .....hence alot more snow as long a the Air was very cold.
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Quoting tornadodude:

Hey tornadodude.. how did u get the map.. I like the graphics on it lol
Member Since: August 15, 2008 Posts: 0 Comments: 2133
it sounds like fun aussie...and the Grand Prize is a years' worth of serious braggin' rights...
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Quoting Chicklit:
Here's a Sci-Fi shift: Poles switch to equators and Ecuador becomes the north pole; Phillipines the south pole.

Have you watched the movie 2012?
BTW I hope that never happens
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Quoting Grothar:


Try 14! It is about 8 miles from downtown Miami, but about 14 from Miami Beach.

Boy does that make me feel better about the 75 dollar cab fare...
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Quoting FLPandhandleJG:
well if u get a big artic air mass that dives south to the GOM.. To me, if bands were to form like lake effect, wouldnt u have to have a stall warm front in the GOM with alot of moisture pumping in with the jet stream, bc when they get lake effect snow is it usually the wind from the north bring the moisture or depends on a L or front? or please explain if it could happen.. thx


Lake effect snow occurs when a cold air rushes over open water that is not frozen. The open water is warmer than the air above causing Lift and instablitity just like a thunderstorm in a sense therefore Snow because of the cold temps aloft and at surface.
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Quoting TampaSpin:


Road Kill........ROFLMAO
heheheheheheh
Member Since: July 15, 2006 Posts: 171 Comments: 53809
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sry for bringign up on lake effect and if it or could not happen in GOM on circumstances.. thx for the replies.. :)
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.