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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I have a question for everyone. I've been reading the this blog and NWS statements and the models all day. It seems this Siberian High is pushing the storm south and it now seems like South Florida and Central Florida East Coast are in for one hell of a snowstorm saturday evening. Your thoughts?
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Member Since: August 15, 2008 Posts: 0 Comments: 2133
38.6 degrees in Oakland Park, FL @ 8:50 PM. Had frost on my car this AM briefly. I think metro broward county can expect frost tonight bigtime
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Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting hydrus:
Whatever happens, it will definitely feel cold and raw in and around the Florida Capitol tonight.


It was dropping quite quickly. I walked into Walmart at around 6:15 got out around 6:40 and it was so much colder.
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1084. hydrus
Quoting ElConando:
33 degrees in Tallahassee right now. Lows have been lowered to below freezing Thursday night!!! 50% rain chance.
Whatever happens, it will definitely feel cold and raw in and around the Florida Capitol tonight.
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Amazing, btw, that temps are supposed to stay below 75 here during that time period. Last year we were having record highs of 82-83 in January, yet.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
Quoting VAbeachhurricanes:


can you post that same map, but the gfs model? plz TIA


I cant find a GFS map like the NAM Model from Accuweather.com. unless someone can get it.. I know tampaspin has a goodone, but i dont have the link or anything unless sum1 would like to share.. thanks if u do.. sry VAbeach!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting dayton:
Could someone please give me a 10 day forecast for Nassau, Bahamas.
Thanks
Wunderground has one posted here.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
Quoting IKE:
Amarillo, Texas (Airport)
Updated: 15 min 43 sec ago
Light Freezing Drizzle
19 �F

Light Freezing Drizzle Mist
Windchill: -1 �F
Humidity: 93%
Dew Point: 18 �F
Wind: 34 mph from the North
Wind Gust: 44 mph

Pressure: 30.16 in (Rising)
Visibility: 2.5 miles
UV: 0 out of 16
Clouds:
Overcast 600 ft
(Above Ground Level)
Elevation: 3606 ft


Holy lord that is some wind!
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1079. IKE
Amarillo, Texas (Airport)
Updated: 15 min 43 sec ago
Light Freezing Drizzle
19 F

Light Freezing Drizzle Mist
Windchill: -1 F
Humidity: 93%
Dew Point: 18 F
Wind: 34 mph from the North
Wind Gust: 44 mph

Pressure: 30.16 in (Rising)
Visibility: 2.5 miles
UV: 0 out of 16
Clouds:
Overcast 600 ft
(Above Ground Level)
Elevation: 3606 ft
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1078. aquak9
m'eyeballs freezin out here..


ya'll have a warm one.
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1077. dayton
Could someone please give me a 10 day forecast for Nassau, Bahamas.
Thanks
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28 degrees at Tallahassee airport.
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1075. unf97
Quoting aquak9:
unf- - 35.8 here, you must be further inland...well you are a little further north, too. Maybe ten miles further north.


I am inland in northern Duval county within about 5 miles from JIA. (near Dunn Ave. area near I-295)
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1074. IKE
34.9 outside my window.
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Siberian Express Flight # -35 is now arriving for Ponca City, Oklahoma City, OK, Wichita Falls, TX to near Lubbock, TX.

Member Since: August 25, 2009 Posts: 20 Comments: 6785
1072. aquak9
unf- - 35.8 here, you must be further inland...well you are a little further north, too. Maybe ten miles further north.
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Quoting FLPandhandleJG:



can you post that same map, but the gfs model? plz TIA
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Quoting Jeff9641:
There is a chance the winter of 2010 will not stop at record cold and frequent freezes along the Gulf Coast. AccuWeather.com meteorologists are pondering the possibility of snow for the Sunshine State this weekend.


A storm could hook up with fresh cold air in such a way that rain ends a period of snow or sleet Saturday night into Sunday over the Florida Peninsula. That's right, we said Peninsula and not Panhandle.


Snow events in the Florida Panhandle are rare enough. However, the white stuff is almost unheard of farther south.


During Jan. 19, 1977, flurries flew in Miami. A bit of snow fell more recently at Daytona Beach during Jan. 24, 2003.


Will this weekend yield snow in Orlando, Melbourne, Jacksonville and Cape Canaveral? Time will tell.


Story By AccuWeather.com Expert Senior Meteorologist Alex Sosnowski

Forums: Chat About This Weather Story


that was from b4 noon.. alot will change with these models.. right now its hearsay.. once L forms or not.. they will have a better idea or how much moisture there will be.. right now its hard to stay .. b/c models keep flip floping.. even with a day b4.. its madness i tell ya.. ;)
Member Since: August 15, 2008 Posts: 0 Comments: 2133
1069. KEEPEROFTHEGATE (Mod)
Quoting Jeff9641:
There is a chance the winter of 2010 will not stop at record cold and frequent freezes along the Gulf Coast. AccuWeather.com meteorologists are pondering the possibility of snow for the Sunshine State this weekend.


A storm could hook up with fresh cold air in such a way that rain ends a period of snow or sleet Saturday night into Sunday over the Florida Peninsula. That's right, we said Peninsula and not Panhandle.


Snow events in the Florida Panhandle are rare enough. However, the white stuff is almost unheard of farther south.


During Jan. 19, 1977, flurries flew in Miami. A bit of snow fell more recently at Daytona Beach during Jan. 24, 2003.


Will this weekend yield snow in Orlando, Melbourne, Jacksonville and Cape Canaveral? Time will tell.


Story By AccuWeather.com Expert Senior Meteorologist Alex Sosnowski

Forums: Chat About This Weather Story


fla is getting snow i got it on special order
Member Since: July 15, 2006 Posts: 174 Comments: 54420
Hey jeff9641 How are you doing. What are your thoughts for after this weekend?
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1066. unf97
Current temp reading 32.8 degrees.

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Member Since: August 15, 2008 Posts: 0 Comments: 2133
I need lot of moisture for my cold air!..lol..
looks like Mobile is going to miss the snow again...:( oh well, maybe next time..
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33 degrees in Tallahassee right now. Lows have been lowered to below freezing Thursday night!!! 50% rain chance.
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Hi All forget the pressure reading. Been wacko for weeks. Its ok on my weather station but stuck on my computer. Its really 1019.5
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1061. KEEPEROFTHEGATE (Mod)
Quoting BahaHurican:
Whoo hoo!!!! not even 8 p.m. yet and already down to 59 degrees here in Nassau!!!! Now that's CHILLY.....

Something u Americanos may not know / realize is that houses in the Bahamas are built sans heating / insulation. This means that the house is coooling down with the outside temps, so that if it's 55 outside, it's likely to be at most 7 - 10 degrees warmer inside. Last night when it was 62 outside, it was 67 inside.

I think I'm going to need a couple pairs of socks with that extra blanket tonight..... LOL....
hey baha a little tip to stay warmer make sure all windows and doors are close in the house and put a full kettle of water to boil away on the stove the evaporating water from kettle will increase humity levels in your house and make the cooler temps feel warmer by creating a humdex in your home
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Quoting charlottefl:
I have a question. Is our low in W. TX the low we're looking to start generating all of this wintry precipitation or has it not formed yet?


Please read this very well written and simply explained Area Forecast Discussion Link for NWS Tampa, FL:
Link
Member Since: August 25, 2009 Posts: 20 Comments: 6785
1059. IKE
Quoting Drakoen:


I think you will get some rain and a brief period of flurries with no accumulation, at this time. he thickness criteria does not look any different to me for you than areas that are farther west in the northwestern panhandle. Thickness values would be between 540dm and 546dm on the 100mb-500mb. The PBL looks around 1260gpm and thickness around 1500gpm in the 850mb-700mb.


Thanks for the information.
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From Wikipedia- snowfall events for Florida.
Link
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Quoting eddye:
will it snow in se fl


The odds are very slim, below is a portion of the NWS Miami Area Forecast Discussion @ 3:56PM EST today:

...THERE IS ALSO A
REMOTE CHANCE THAT SOME SLEET OR ICE PELLETS MAY MIX WITH RAIN IN
THE LAKE OKEECHOBEE AREA ON SATURDAY/SATURDAY NIGHT. REGARDLESS...
A VERY COLD AIR MASS WILL CONTINUE TO SPREAD ACROSS THE AREA ON
SATURDAY NIGHT...WITH RAIN CHANCES AND CLOUD COVER GRADUALLY
DIMINISHING FROM NORTH TO SOUTH. THERE IS AN ELEVATED POTENTIAL
FOR FREEZING TEMPERATURES ON SATURDAY NIGHT...BUT THIS WILL BE
DEPENDENT ON HOW QUICKLY CLOUDS DEPART. THE GFS/ECMWF AGREE THAT A
SECONDARY MID-LEVEL VORT MAX MOVING AROUND BASE OF DEEP UPPER
TROUGH OVER EASTERN NORTH AMERICA WILL MOVE ACROSS THE PENINSULA
ON SUNDAY...AND INDUCE SURFACE CYCLOGENESIS OVER THE ATLANTIC
WATERS EAST OF THE PENINSULA. THIS WILL ALLOW BRISK NORTHWEST
WINDS TO INCREASE EVEN FURTHER...WITH COLD TEMPERATURES EXPECTED
THROUGH THE DAY ON SUNDAY...AND AN EVEN HIGHER FREEZE POTENTIAL ON
SUNDAY NIGHT/MONDAY MORNING. A GRADUAL WARMING TREND IS STILL
EXPECTED FROM MONDAY-WEDNESDAY.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
I have a question. Is our low in W. TX the low we're looking to start generating all of this wintry precipitation or has it not formed yet?
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1055. Drakoen
It's already 39 at my house in suburban Lake Worth
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Whoo hoo!!!! not even 8 p.m. yet and already down to 59 degrees here in Nassau!!!! Now that's CHILLY.....

Something u Americanos may not know / realize is that houses in the Bahamas are built sans heating / insulation. This means that the house is coooling down with the outside temps, so that if it's 55 outside, it's likely to be at most 7 - 10 degrees warmer inside. Last night when it was 62 outside, it was 67 inside.

I think I'm going to need a couple pairs of socks with that extra blanket tonight..... LOL....
Member Since: October 25, 2005 Posts: 19 Comments: 22322
Quoting code1:
Isn't it funny how the change of seasons makes us change our wishcasting talk? Cane season, we wish them to go elsewhere, snow season....bring it to FL! LOL


Couldn't have said it any better.
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1052. eddye
will it snow in se fl
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you guys in the freeze areas:

REALLY BE CAREFUL DRIVING SNOW IS NOT THE PROBLEM IT'S THE BLACK ICE. IF YOU THINK YOU HAVE HIT SOME DO NOT BRAKE!!!
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SNOW!!

The GFS 18Z is forecasting quite a bit of snow for central FL.

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NOAA NWS Houston-Galveston, TX link below:

Link

A portion of NWS Houston/Galveston, TX Area Forecast Discussion, 5:38PM Today:

HAVE ADJUSTED HOURLY
TEMPS THURSDAY CLOSER TO WHAT GFS BUFR GUIDANCE IS SUGGESTING.
STILL EXPECT GOOD COVERAGE OF LIGHT RAIN OVERNIGHT ESPECIALLY
SOUTHERN HALF. 18Z BUFR SOUNDINGS REMAIN SUPPORTIVE OF A PERIOD
OF SLEET OVER OUR NW ZONES MAINLY 13-18Z THURSDAY...POSSIBLY
DEVELOPING AS FAR SOUTH AS IAH FOR A SHORT WINDOW 16-18Z.
SOUNDINGS SUPPORT A MIX OF RAIN AND SLEET. REMOVED MENTION OF
SNOW. WHILE A FEW FLURRIES ARE POSSIBLE THE SOUNDINGS ARE MUCH
MORE SUPPORTIVE OF SLEET. STILL EXPECT WINTRY PRECIP TO BE VERY
LIGHT AND TEMPS MAINLY ABOVE FREEZING SO NO ADVISORY WILL BE
ISSUED.
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Quoting nrtiwlnvragn:
Area snow fell in Florida on Jan 19, 1977



LOL @ the wind chill factors.
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1046. code1
Isn't it funny how the change of seasons makes us change our wishcasting talk? Cane season, we wish them to go elsewhere, snow season....bring it to FL! LOL
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Crazy cold is approaching! My barometer here in Arlington, TX, has jumped from 29.99" to 30.05" in the last 45 minutes and yes, it's working properly and was set properly!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Canekid98:
uhhh, can i please have a Houston wx discussion? Also what is the chance for snow here? it says highs tommorow of 37 and rain?

The non-Florida weather blog is on vacation. Please check back in a week.

honestly though, snow here in Houston isn't looking very likely. The moisture will likely miss the super-cold air on Thursday. As for Saturday, two models (NAM and Canadian) are saying there is a chance, and two models (GFS and ECMWF) are saying it will be too dry.
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1043. KEEPEROFTHEGATE (Mod)
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1042. KEEPEROFTHEGATE (Mod)
img src="http://" width="1024" height="791" alt="" />
Member Since: July 15, 2006 Posts: 174 Comments: 54420
Quoting aquak9:
so much south/central florida taking a hit on agriculture...but it's all across the country.

carry on...


The freezing weather country destroyed my potato plants; they went from a captivating green to an ominous dark color.
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And if "Siberian Blast, Flight# -35" does bring wintery precip to FL, many will be doing this:



Member Since: August 25, 2009 Posts: 20 Comments: 6785
Area snow fell in Florida on Jan 19, 1977

Member Since: September 23, 2005 Posts: 14 Comments: 11215

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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.

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