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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sry for bringign up on lake effect and if it or could not happen in GOM on circumstances.. thx for the replies.. :)
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting presslord:
here ya go aussie
Link

Thanks, I actually saw it earlier and read all about it. Would it be worth my while joining the competition?
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337. jipmg
Finally dropping, 47 in miami now NNW at 5mph, clear, dew point dropped to 36.
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Quoting atmoaggie:

Really, it is directly inland from Miami Beach by about 5 miles.


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


Man..Baha, I am sorry. I know how much you dislike the cold. Be patient a few more days, and this will pass. I must imagine after 12 mos of high near 90F, lows near 75F, that 60F to you feels like 15F would to me!
Lol was just saying something similar to a family member.... It was so warm last month that this 61 feels like killer cold. Mind u, the avg. low temp here is around 68, so 60 is still chilly for us. The bigger irony of my story is that 2 weeks ago I was in Boston, where it was 21 degrees.

I feel colder now..... lol
Member Since: October 25, 2005 Posts: 19 Comments: 21883
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.
don't listen to that model by thats only good in southern ontario

lol

Member Since: July 15, 2006 Posts: 170 Comments: 53517
Here's a Sci-Fi shift: Poles switch to equators and Ecuador becomes the north pole; Phillipines the south pole. Or would that be Australia? American education in the 50s and 60s was sorely lacking in geography.
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Quoting presslord:


...yea...I've been wonderin' the exact same thing...

Sure you have. LOL!
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Quoting pussinboots:
Dr. Masters,

Could you please comment on the exact definition of error? Is it the simple sum of Euclidean distances between predicted and actual locations, for each prediction? Or is it the L2-norm of the distances (treated as a vector)?

Thanks,

Jason


Track forecast error is defined as the great- circle distance between a cyclone's forecast position and the best track position at the forecast verification time.

Link
Member Since: September 23, 2005 Posts: 14 Comments: 11053
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
Member Since: August 15, 2008 Posts: 0 Comments: 2133
As a native Texan who grew up in New Mexico and then again in Texas real chili contains beef, venison or road kill.

Um. Great receipe.
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Quoting FLPandhandleJG:


But wouldnt the gulf would have to be close to freezing since the great lakes are usually cold half the time or just depends how cold it is?


In the Panhandle the GOM temp would not have much of any bearing since the air would be coming from the North unless an area of Low pressure was to develop and push a NorEAster type event into the Panhandle.
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Quoting atmoaggie:


He is stating that there is something to alarmed about in the SSTs and SST anomalies. I am stating that it is El Nino, a little scary, but alarming only the first time one studies one.

And the great big warm pool in the south-central Pacific? Yep, was present for the mild 2006-2007 Nino, too.



Agree Atmo, Monthly Ocean Briefing had nothing out of the ordinary that I saw.
Member Since: September 23, 2005 Posts: 14 Comments: 11053
Quoting pussinboots:
Dr. Masters,

Could you please comment on the exact definition of error? Is it the simple sum of Euclidean distances between predicted and actual locations, for each prediction? Or is it the L2-norm of the distances (treated as a vector)?

Thanks,

Jason


...yea...I've been wonderin' the exact same thing...
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I saw no "alarming" in his post. Just the facts. Atmo was describing a situation, period.
You can derive and make points all you want.
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Dr. Masters,

Could you please comment on the exact definition of error? Is it the simple sum of Euclidean distances between predicted and actual locations, for each prediction? Or is it the L2-norm of the distances (treated as a vector)?

Thanks,

Jason
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not as bad, but still cold!!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
If the clouds would've held off till morning the temp. would have been allowed to drop thus flurries would've been possible.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting AussieStorm:

So is it or isn't it open to people outside of the USA?


world wide web

enter an email and wunder ground site password or password hit enter you should be in if ya not a wunder ground subscriber shoot me a email and i will give ya a free one year membership i have a link on my blog to contest
Member Since: July 15, 2006 Posts: 170 Comments: 53517
Quoting jipmg:


Do you think the GFS may be correct? Snow in south west florida possible?


The NAM is very good for short term forecasting....Let's see what it does in the next run....seems the Temps for tonite is going to be colder than models first thought even recently.....so Lets watch what the 00Z forecast brings.
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Ahh, not many models showing New Orleans snow any longer...bummer! I am still optomistic about the strength of the disturbance over mexico right now
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If it snows goin to drink meh bottle of 15 yr. old Guyana Rum and fall flat on meh back in that snow.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
here ya go aussie
Link
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314. jipmg
Quoting FLPandhandleJG:


But wouldnt the gulf would have to be close to freezing since the great lakes are usually cold half the time or just depends how cold it is?


Tampa itself was getting that affect last night, the clouds formed, and light rain showers developed, while tampa was into the 30s, but what happened was the gulf's heat made the temperature go up almost significantly when the clouds and light showers started moving in.
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I have seen it snow in SWFL, (Port Charlotte) in 1989 Dec 24th. It was 25 degrees outside. It was very light flurries, but it is possible.
Member Since: December 18, 2006 Posts: 7 Comments: 2686
Quoting Chicklit:


He is stating the obvious.


He is stating that there is something to alarmed about in the SSTs and SST anomalies. I am stating that it is El Nino, a little scary, but alarming only the first time one studies one.

And the great big warm pool in the south-central Pacific? Yep, was present for the mild 2006-2007 Nino, too.

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Quoting Bordonaro:


A combination of both.


Hey Bob.. how r u Sir?? anything interesting today?
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Ego entering observations leads to skewed opinions.
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aussie...I'm sure it must be...Dr. M posted a link to it in the comments earlier...I'll try to find it for you...
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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.


To quote NRAamy "hahahahahaha" :)
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Quoting TampaSpin:


Your gonna get some snow...I am starting to be very confident of that.


But wouldnt the gulf would have to be close to freezing since the great lakes are usually cold half the time or just depends how cold it is?
Member Since: August 15, 2008 Posts: 0 Comments: 2133
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.


Road Kill........ROFLMAO
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Quoting GTcooliebai:
umm... you think soo or could the buildings have anything to do with it I once heard of the term "Urban Heat Island"


A combination of both.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
304. jipmg
Quoting TampaSpin:


Your gonna get some snow...I am starting to be very confident of that.


Do you think the GFS may be correct? Snow in south west florida possible?
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Quoting atmoaggie:


I was getting an SST anomaly map, too.

This is all about 0.5 to 1.5 C SST anomalies? Hey, guy, our planet's fluids are constantly in a highly variable state.



The anomalies are not all 1.0C - 1.5C. Some of the anomalies at the equator are closer to 3C, and the South Pacific pool is more prominent. Also notice the ENSO pool extending to Chile. The Gulf Stream itself has warm anomalies, but the waters surrounding it are cooler than normal. The usually cool areas are warmer than normal.
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So what did the 2002-2003 Nino do in the way of SST anomalies?

This:


Today is not very different or special.
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Quoting atmoaggie:

Yeah? That is what Nino does.

I have to tell ya, so far I think you are playing chicken little. What can I say? Maybe you are onto something that no one else in the field will recognize for months. Or maybe you are looking really hard for climate disaster, and, thus, finding it.


He is stating the obvious. But not everyone can put it so eloquently as this Observer.
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Quoting presslord:
OK...I asked Dr. Masters about a little 'side action' on the forecsst contest...and he didn't say 'no'...he actually didn't say 'yes' either...but I have found it's usually better to ask for forgiveness than permission...

so...I am going to pick someone to back in the contest...and commit to a $500 contribution to Portlight if they win...

so...if you are planning to participate in the contest...and want a shot at being the horse I back...shoot me a WU mail...

I will pick someone by placing all the names in a coffee mug and having my daughter draw one at random...

So is it or isn't it open to people outside of the USA?
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Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting jipmg:


is that why its showing mid and low 40s across most of those observations, while the airport is showing 49


Within the same zone the airport is in the range is currently 46-49.
Member Since: September 23, 2005 Posts: 14 Comments: 11053
Quoting BahaHurican:
Bord, our airport is reporting 61 as of 9 p.m.

The thermometer I stuck outside 20 min ago says 62.... lol


Man..Baha, I am sorry. I know how much you dislike the cold. Be patient a few more days, and this will pass. I must imagine after 12 mos of high near 90F, lows near 75F, that 60F to you feels like 15F would to me!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
296. 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.
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Quoting FLPandhandleJG:

That would be interesting.. I would love to c sum snow.. but my chances r getting slim.. unless something happpens.. so what do u think? just freezing rain maybe sleet if that..


Your gonna get some snow...I am starting to be very confident of that.
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Look at Immokalee sitting cool at 39 just goes to show you the affect water has on surface temp. MIA is at 49, 10 degree diff.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting TampaSpin:
Crazy as this would seem but, i wonder if the GOM could also produce snow bands like the ones seen from the Great Lakes if it was cold enough in Florida.


Hmmmm, maybe?

excerpts from weather.com

Lake Effect Snow
Lake effect snows occur when a mass of sufficiently cold air moves over a body of warmer water, creating an unstable temperature profile in the atmosphere.

As a result, clouds build over the lake and eventually develop into snow showers and squalls as they move downwind.

The most likely setting for this localized type of snowfall is when very cold Arctic air rushes over warmer water on the heels of a passing cold front, as often happens in the Great Lakes region during winter.

Since cold air can hold very little moisture and the low level of the atmosphere is quite unstable, clouds form very rapidly, condensation occurs and snow begins to fall. Lake effect snow is lighter than snow that forms from frontal stratus or nimbostratus.

Cape Cod Bay in Massachusetts and Chesapeake Bay in Maryland and Virginia, on occasion, produce what is called bay effect snow. Bay effect snow forms in the same manner as lake effect snow, only over the ocean.
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Quoting AstroHurricane001:


How are you even supposed to forecast the POP? Do you put either 0 or 100? I think I did an intermediate number similar to normal forecasts.


Was wondering that myself, how do they "score" POP? If you were to say 50% you loose the same no matter if it did/did not?
Member Since: September 23, 2005 Posts: 14 Comments: 11053
Quoting AstroHurricane001:
Here are the subsurface temperature anomalies at the equator. Notice the warm anomaly drifting east and upward.

Yeah? That is what Nino does.

I have to tell ya, so far I think you are playing chicken little. What can I say? Maybe you are onto something that no one else in the field will recognize for months. Or maybe you are looking really hard for climate disaster, and, thus, finding it.
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the warmest waters are not extending from the coast of Peru and Equador, but rather from the Central Pacific, extending farther east. The warm pool in the Southern Pacific is also abnormal, and this "bulge" in oceanic isotherms was created when Mick and other extratropical systems funelled warm ENSO water southward toward Antarctica.

If you look at SST anomalies, the warmest anomalies are along the Gulf Stream (as well as the coldest anomalies) and in the High Arctic. However, the warmest large anomaly is the one in the South Pacific.

AstroHurricane1, well said!
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289. jipmg
Quoting nrtiwlnvragn:


The airport is in the "Metropolitan" zone, and its reading is not much different from other areas in the same zone. Lower readings are seen in the "Inland" zone.

Link


is that why its showing mid and low 40s across most of those observations, while the airport is showing 49
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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.