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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24F here along the ICW on Johns Island
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just got home from work and the temp on the drive home reached 23 in places.
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1287. IKE
Morning low has been 28.6, so far.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Morning All.

More significant than the evening lows

Statement as of 6:30 PM EST on January 06, 2010

... Record low maximum temperature set at West Palm Beach...

A record low maximum temperature of 55 degrees was set at West Palm Beach
today. This breaks the old record of 57 set in 1919.
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This is to strange.You folks are the same temp as here. Updated: 3:54 AM CST on January 07, 2010
22 °F
Overcast
Windchill: 12 °F
Humidity: 85%
Dew Point: 18 °F
Wind: 8 mph from the NNW
Pressure: 30.11 in (Steady)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds: Overcast 700 ft
(Above Ground Level)
Elevation: 1181 ft

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1283. RTLSNK
26.6*F in Macon Georgia right now at 0400 hrs.

Weather statement has lowered the totals we are supposed to get, but still calling for rain/snow. Macon has no salt or sand trucks so it just shuts down here when it snows or ices up the roads. I have a supply of rock salt to clear the driveway. When I tell people here that they go - Rock Salt? What's that for? LOL

Special Weather Statement
Statement as of 3:16 AM EST on January 07, 2010


... Wintry precipitation possible for portions of central
Georgia Thursday evening and overnight...

A frontal system will approach Georgia this afternoon ushering
another round of Arctic air across the area. A wave of low pressure is
developing this morning over the northwest Gulf of Mexico... and
will move into portions of North Florida by this evening. Moisture
from the Gulf of Mexico will spread across Georgia along and ahead
of the frontal boundary.

For areas generally south of a La Grange to Monticello to
Washington line... rain is expected to begin Thursday afternoon
and gradually turn to a rain snow mix during the evening. Precipitation
is then expected to turn to snow by midnight and end Friday
morning. Any snow accumulations across this area will be light
with amounts less than one quarter inch.

For areas north of a La Grange to Monticello to Washington line... please
see the Winter Weather Advisory that has been issued by the
National Weather Service in Peachtree City.

Be especially cautious as wet surfaces refreeze... resulting in patchy
ice on sidewalks and roadways late Thursday night and Friday
morning. Drivers should use extra caution when traveling.

Residents of central Georgia should continue to monitor for
updates to the developing winter weather situation.

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Great minds think alike.
Member Since: July 25, 2006 Posts: 0 Comments: 662
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1279. Patrap
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1278. Patrap
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Snow in Florida is now becoming more of a possibility, will be interesting to see what models show tomorrow. See? I told you that this pattern would favor possible snow all the way down south. Now will the elements come together? Or will we get ripped off? Time will tell. Saturday night will be an interesting night.
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whoa!! whats that i see on my local radar.. lol i doubt we will c that.. its a possibility :P
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I wonder if i broke my all time low lol
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Still not a record but Tallahassee readjusted its low from yesterday from 17 to 16 degrees still one degree off the record of 15.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Tallahassee airport has a reading of 21 degrees... toasty.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting scottsvb:
forecast is really tricky entering the picture for central and north florida this weekend. Alot of issues on things will matter if we see snow in this area.

Cold air in the lower levels will move down into northern and central florida Friday night.. over-running precip as a wave axis rides the front will happen later on Saturday in the midlevels. Its too early and hard to tell exactly how far south the freezing line will be over central florida and how far north the impulse will pull moisture ENE across central florida. Currently it looks like temps by Sat morning will be around 36 in Tampa to 35 in Orlando but in Ocala it could be down to 29-32.By then the mositure should be mainly in S Florida (south of I-4). Now the moisture overide in the midlevels isnt forecasted to really go thru until mid day. Temps by then should be around 41 in Tampa 40 Orlando 37 in Ocala as highs. Cold showers in Central florida.. and probably staying dry in Ocala. As the evening wears on and the moisture starts exiting Saturday night...cold air advection will trail the mositure and a light snow may happen from Pasco Hernado ENE across north central florida to near Orlando-Daytona line.. may see a light coating in the somwhat higher terrain in eastern Hernado area easterward. Temps will fall down to the lower 30s in the evening and 20s before midnight north of I-4 as the flurries-showers end. Morning lows will probably be in the 22-26 range in Ocala Sunday morning and 29-33 along I-4 line. Pinellas county should stay between 35-42 along the coast and near the intercoastal of east florida will probably only drop to the mid 30s. Sunday will be cold will isolated showers coming onshore and highs struggling to reach 45 along the coast to 40 dg inland. Sunday night will be in the 20s most areas with isolated upper 10s.


Very well done Scott! It is all about the timing and arrival of everything....if it all comes together at nite more white stuff is possible......during the day less likely...Could be very interesting and it truly is very complicated to predict what will happen when dealing with frozen precip.
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forecast is really tricky entering the picture for central and north florida this weekend. Alot of issues on things will matter if we see snow in this area.

Cold air in the lower levels will move down into northern and central florida Friday night.. over-running precip as a wave axis rides the front will happen later on Saturday in the midlevels. Its too early and hard to tell exactly how far south the freezing line will be over central florida and how far north the impulse will pull moisture ENE across central florida. Currently it looks like temps by Sat morning will be around 36 in Tampa to 35 in Orlando but in Ocala it could be down to 29-32.By then the mositure should be mainly in S Florida (south of I-4). Now the moisture overide in the midlevels isnt forecasted to really go thru until mid day. Temps by then should be around 41 in Tampa 40 Orlando 37 in Ocala as highs. Cold showers in Central florida.. and probably staying dry in Ocala. As the evening wears on and the moisture starts exiting Saturday night...cold air advection will trail the mositure and a light snow may happen from Pasco Hernado ENE across north central florida to near Orlando-Daytona line.. may see a light coating in the somwhat higher terrain in eastern Hernado area easterward. Temps will fall down to the lower 30s in the evening and 20s before midnight north of I-4 as the flurries-showers end. Morning lows will probably be in the 22-26 range in Ocala Sunday morning and 29-33 along I-4 line. Pinellas county should stay between 35-42 along the coast and near the intercoastal of east florida will probably only drop to the mid 30s. Sunday will be cold with isolated showers coming onshore and highs struggling to reach 45 along the coast to 40 dg inland. Sunday night will be in the 20s most areas with isolated upper 10s.
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okay i wanted to sleep but i am wide awake and i know i wont sleep now.. booo but heres 84 hour temps
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1266. Patrap

Ahh yes,the OOZ run is cool,thankie
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1265. Patrap
That would be "spookie Cold" I guess
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Quoting Patrap:
18 GENS zdp Image Loop,64 frames


hey pat.. when u watch that model run.. does it look like the midwest had an icy question mark during the middle of the run.. u will c ice/red i think that look like a question mark.. lol
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Quoting Patrap:
18 GENS zdp Image Loop,64 frames


Pat the 00 GENS Loop is out.
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1262. Patrap
18 GENS zdp Image Loop,64 frames
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or what happens that L comes past that cold front/artic blast then they think? that would be crazy if that happens.
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1260. Motttt
Current Conditions


Ridge Lake, Sarasota, Florida (PWS)
Updated: 2 min 45 sec ago
35.9 °F
Clear
Windchill: 36 °F
Humidity: 88%
Dew Point: 33 °F
Wind: 0.0 mph
Wind Gust: 0.0 mph
Pressure: 30.22 in (Falling)


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Possible percipitation amounts!
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Quoting TampaSpin:


We should know or have a better idea tomorrow nite....as it will be 24hrs out.

if its 24hours out then they would have to extend the forecast like i was mentioning earlier today when i was looking at most of the models.. if thats true then the temps on friday will be little colder than thursday temps.. what ya think Tim?
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Quoting FLPandhandleJG:

it could go either way or vice versa! ha


We should know or have a better idea tomorrow nite....as it will be 24hrs out.
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Quoting TampaSpin:
New model just came out......

I would say Florida is back for wintery stuff.......LOL


it could go either way or vice versa! ha
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Quoting TampaSpin:


Hey JG i lived up north in Indiana and winter precip is the hardest to call by far. Even as good as technology is today they don't do a good job at forecasting winter precip until the last 24hrs and then it can be very wrong.


ya its pretty bad down here, even the mets close to me dont know how to track a hurricane right or they blow it off, then boom that storm is form and there like well its b/c it was in the GOM and pretty warm thats y and it fought a great fight to b where it is.. lol thats just for example.. Im like okay and u call urself a chief Meteorologist(spelling).. im about to fall asleep sry if i didnt spell anything right.. but ya i dont trust them mets down here one bit.. sry if sum ppl do down here..
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New model just came out......

I would say Florida is back for wintery stuff.......LOL

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I still think and believe the Florida Panhandle and North Florida will see winter white stuff in some form.
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Quoting FLPandhandleJG:


Hey Tim.. How was ur day Sir.. Ya Models and forecast discussions have been goin back and forth.. now its rain/sleet for me for now.. but anything can happen I will b def on in the morning or so..


Hey JG i lived up north in Indiana and winter precip is the hardest to call by far. Even as good as technology is today they don't do a good job at forecasting winter precip until the last 24hrs and then it can be very wrong.
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Quoting ElConando:


Snow in Mexico? oy ye meh!!!!


sure looks like it.. i would doubt it if they do or not.. or im not counting us out, but right now its up in the air.. but we will c .. if i would say maybe a mix but got a feeling we will get a surprise thursday night into early friday morning.. ;)
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Quoting FLPandhandleJG:


sorta sounds 'like day after tomorrow,' when the temps went down in seconds.. but it wont b like that with over -150 degree's, that would b rediculous.. burrrr.. stay warm bob and maybe we can get sum snow.. i guess im goin to get sum shut eye and catch up in the AM or later sumtime.. Ya'll have a good night..


Not gonna happen like that movie, thankfully! Sleep well, I am about to lay down. I know the strong N winds will howl and wake me up!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting TampaSpin:
Good early morning everyone......The models have only backed of slightly.....LOOKS like a Sleet event rather than a snow event for Florida will be likely.


Hey Tim.. How was ur day Sir.. Ya Models and forecast discussions have been goin back and forth.. now its rain/sleet for me for now.. but anything can happen I will b def on in the morning or so..
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Here is why it will probably be Sleet. We will have 3 different layers of Air....at the highest levels a flake will fall.....then it will turn into a raindrop as the LOW will pump some warmer air to the MId Levels then at the surface we will have colder air below freezing in Northern Florida...JUst my opinion but, i see a Sleet event in the North Florida area and maybe as far south into Central Florida possible.
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Quoting ElConando:


Well of course the sirens went off, you were SAM-MOKIN!!!


The "tornado sirens" normally don't pull the "false alarm number". The Dallas Ft Worth area has a whole slew of severe t-storms to deal with every spring. They also use them when high winds move in. A North wind at 20-30MPH doesn't fit the criteria.

I was smoking a 100% Marlboro Medium?!? Honest!

Update, Arctic front arrived at 12:34AM CST 1-7-10..Let the fun begin..
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Bordonaro:
Extremely weird. I was outside, smoking a cigarette, and the Severe Weather Sirens were going off!

The leading edge of the Arctic Cold Front is moving through the Dallas-Ft Worth, TX area from NW to SE.

The Ft Worth Naval Air Station has N winds at 25 G 33MPH.

Arlington AP has SW winds at 6MPH.

Gonna get nasty cold, quick!


sorta sounds 'like day after tomorrow,' when the temps went down in seconds.. but it wont b like that with over -150 degree's, that would b rediculous.. burrrr.. stay warm bob and maybe we can get sum snow.. i guess im goin to get sum shut eye and catch up in the AM or later sumtime.. Ya'll have a good night..
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Quoting TampaSpin:
Good early morning everyone......The models have only backed of slightly.....LOOKS like a Sleet event rather than a snow event for Florida will be likely.

What about the cold? Will it be even colder here than the last two days?
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Quoting TampaSpin:
Good early morning everyone......The models have only backed of slightly.....LOOKS like a Sleet event rather than a snow event for Florida will be likely.


Quite frankly raining at 40 degrees for me is bad enough lol. If I want snow i go to it, it does not come to me!!!
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Good early morning everyone......The models have only backed of slightly.....LOOKS like a Sleet event rather than a snow event for Florida will be likely.
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Quoting FLPandhandleJG:


Snow in Mexico? oy ye meh!!!!
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting Bordonaro:
Extremely weird. I was outside, smoking a cigarette, and the Severe Weather Sirens were going off!

The leading edge of the Arctic Cold Front is moving through the Dallas-Ft Woth, TX area from NW to SE.

The Ft Worth Naval Air Station has N winds at 25 G 33MPH. Arlingto AP has SW winds at 6MPH.

Gonna get nasty cold, quick!


Well of course the sirens went off, you were SAM-MOKIN!!!
Member Since: September 6, 2009 Posts: 2 Comments: 3784
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1239. unf97
Going to get some shut-eye for now. As I turn in for some sleep, the temperature now down to 25.2 degrees in north Jax.

Back on in awhile to check the updated model runs!

Have a good night/early morning everyone.
Member Since: September 25, 2007 Posts: 0 Comments: 1193

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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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