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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Lafayette, Purdue University Airport
Lat: 40.43 Lon: -86.93 Elev: 623
Last Update on Jan 6, 10:54 am EST

Fair

11 °F
(-12 °C)
Humidity: 73 %
Wind Speed: SW 7 MPH
Barometer: 30.26" (1025.9 mb)
Dewpoint: 4 °F (-16 °C)
Wind Chill: 0 °F (-18 °C)
Visibility: 9.00 mi.
Member Since: June 28, 2006 Posts: 25 Comments: 8347
Just talked to friend in Basingstoke England and he is snowed in too. Couldn't even think of going to work.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting StormChaser81:


It all depends on were that low goes if it more north Tallahassee and the panhandle could get snow on the back side of it. Because temps should be lower if that happens.


kk
Member Since: Posts: Comments:
Quoting ElConando:
If snow/flurries were to happen I dunno if it could happen thursday, low of 33-34 degrees.


It all depends on were that low goes, if it goes more north Tallahassee and the panhandle could get snow on the back side of it. Because temps should be lower if that happens. I've seen it snow in Tallahassee when it was 39 degrees with really cold air setting on top.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting catastropheadjuster:


PcolaDan, Thanks for answering me, It would be nice. Right know it's just down right cold. It looks like this will be a unique winter for the south.

Sheri


It's just not right to be this cold without snow for so long. LOL
Also finding out how much my house leeks air. Headed to store to find something to seal the windows that still allows me to open them come spring.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
If snow/flurries were to happen I dunno if it could happen thursday, low of 33-34 degrees.
Member Since: Posts: Comments:
Quoting PcolaDan:


Going to be close Sheri.

Thursday
Cloudy. Chance of rain in the morning...then rain... light sleet likely and slight chance of snow in the afternoon. Little or no snow and sleet accumulation. Highs in the mid 40s. Southeast winds 5 to 10 mph becoming west 5 to 15 mph in the afternoon. Chance of precipitation 70 percent.

Thursday Night
Cloudy. Chance of snow in the evening. Lows in the lower 20s. North winds 10 to 20 mph. Chance of snow 30 percent. Little or no snow accumulation in the evening.


PcolaDan, Thanks for answering me, It would be nice. Right know it's just down right cold. It looks like this will be a unique winter for the south.

Sheri
Member Since: Posts: Comments:
Quoting ElConando:


You lived in North Dakota?


Yep, 5 years. USAF. "Why not Minot, freezin's the reason"
Member Since: August 22, 2008 Posts: 12 Comments: 6010
00 GENS zdp Image Loop,64 frames thru Jan 22
Member Since: Posts: Comments:
Quoting ElConando:


you've been getting better and better man, keep it up. You think The Panhandle could get a whiff of snow?


Thanks, I think your forecast up there says rain/snow Thursday night, then Flurries on Friday night. Lets see how models deal with this new evolving situation. I can only imagine what a very cold winter can do to a forecasted active hurricane season for 2010.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
The forecast Thursday night is calling for a 50% chance of snow here in Pensacola. I still don't buy it...we'll see.
Member Since: Posts: Comments:
Quoting PcolaDan:
Don't know how I ever survived this place.



You lived in North Dakota?
Member Since: Posts: Comments:
My cousins live there now. They've had a ton of snow recently.

Quoting PcolaDan:
Don't know how I ever survived this place.

Member Since: December 18, 2006 Posts: 7 Comments: 2686
I wonder if we can pull some lake effect snow off of Lake O.
Member Since: Posts: Comments:
724. unf97
Quoting reedzone:


I had mentioned this a few times, before this pattern evolved. I got bashed for this, even a disgusting MET on here was ignorant to me. I predicted that somehow through this pattern, it can snow in Florida. The pattern could be one with southern storm tracks and very cold weather. Snow is possible, but the ingredients have to be right, so far, the elements are looking tight.


That's right. Because the Polar Jet is placed so far to the south, these shortwaves diving rapidly S-SE down the jet can trigger snow events with Arctic air in place in the Deep South. It's simply a matter of timing and the location of where a developing area of low pressure takes shape. It's a fascinating weather extreme, which makes following and analyzing weather so intriguing!
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting reedzone:


Heck, I was even bashed and ignored by lots of bloggers for saying Hurricane Bill would scrape the New England coastline when the models had it hitting Bermuda at the time.. We all aren't perfect, no reason to bash people for predictions, even if they are stupid.


you've been getting better and better man, keep it up. You think The Panhandle could get a whiff of snow?
Member Since: Posts: Comments:
Don't know how I ever survived this place.

Member Since: August 22, 2008 Posts: 12 Comments: 6010
NAM has been quite consistent at bringing the 0C isotherm right on CFL along with a band of moisture as depicted below:

Link

If this pans out then a wintry mix to SNW/RW could be possible across CFL and north on Sat.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
Quoting catastropheadjuster:
Hey Everyone, I was wondering with all this snow floating around does anyone think Mobile,Alabama might get any. I would love it. So would my grandson.

Sheri


Going to be close Sheri.

Thursday
Cloudy. Chance of rain in the morning...then rain... light sleet likely and slight chance of snow in the afternoon. Little or no snow and sleet accumulation. Highs in the mid 40s. Southeast winds 5 to 10 mph becoming west 5 to 15 mph in the afternoon. Chance of precipitation 70 percent.

Thursday Night
Cloudy. Chance of snow in the evening. Lows in the lower 20s. North winds 10 to 20 mph. Chance of snow 30 percent. Little or no snow accumulation in the evening.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Jeff9641:


I had my doubts but i have to admit you were right.


Heck, I was even bashed and ignored by lots of bloggers for saying Hurricane Bill would scrape the New England coastline when the models had it hitting Bermuda at the time.. We all aren't perfect, no reason to bash people for predictions, even if they are stupid.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
The GOM IR Loop shows the Low level clouds on the move E Ne..



Member Since: Posts: Comments:
Quoting Jeff9641:


With snow or ice no sun for sure. The models are just now latching on to this so a change in those forecast will be fourth coming. A cut off low on the coast of Fl or just off shore with arctic air in place is amazing.


Even if the GFS verifies, flurries will be hitting the coastline from a wicked band out in the ocean.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Quoting unf97:


Oh yeah, I remember that rare ice and snow event here Dec. 22-23,1989. That was something alright.. I suffered some painful experiences during that event. I won't bore people here discussing that.. Ughh..

But, like then, it was an extreme weather patter pattern similar to what is currently going on right now. We'll see if the models continue to pick up on what the GFS is trending about in future runs.


I had mentioned this a few times, before this pattern evolved. I got bashed for this, even a disgusting MET on here was ignorant to me. I predicted that somehow through this pattern, it can snow in Florida. The pattern could be one with southern storm tracks and very cold weather. Snow is possible, but the ingredients have to be right, so far, the elements are looking tight.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
713. unf97
Quoting reedzone:


I would love to see 2 inches here, nothing more, it's beautiful. I used to live on Long Island 8 years ago, as a kid, I loved the snow. It would be awesome to see some snow here. Hasn't happened in 20 years.


Oh yeah, I remember that rare ice and snow event here Dec. 22-23,1989. That was something .. I suffered some painful experiences during that event. I won't bore people here discussing that.. Ughh..

But, like then, it was an extreme weather pattern similar to what is currently going on right now. We'll see if the models continue to pick up on what the GFS is trending about in future runs.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
So far my local forecasts from wunderground, accuweather, weather, and local news says partly sunny Saturday lol, temps around the low 40s, which I believe if this storm happens, will be more likely to see upper 30s for highs, which is wayy to weird for Florida.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Quoting ElConando:
Storm seems kinda odd that Central Florida gets light snow while the panhandle gets nada. Possibly it could grow. I wonder if freezing rain is possible.


You guys in the panhandle are right on the verge of freezing rain for those days, wouldn't be surprised to see NWS change your forecast to freezing rain or sleet.

Thursday
Night
Chance Rain Chance for Measurable Precipitation 50%
Chance
Rain
Lo 34 F Friday

Mostly Sunny
Mostly
Sunny
Hi 42 F Friday
Night
Mostly Cloudy
Mostly
Cloudy
Lo 18 F
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting Jeff9641:


Hey Buddy, the models have shifted west from earlier runs. We'll see if this continues. SE TX could get snow or ice if this disturbance as well as it enters the Gulf on Sat.


This is sort of what the CMC predicted, but I don't think it latched on to the cut off storm off the East Coast like the NOGAPS did last night.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Hey Everyone, I was wondering with all this snow floating around does anyone think Mobile,Alabama might get any. I would love it. So would my grandson.

Sheri
Member Since: Posts: Comments:
Storm seems kinda odd that Central Florida gets light snow while the panhandle gets nada. Possibly it could grow. I wonder if freezing rain is possible.
Member Since: Posts: Comments:
Quoting Jeff9641:


I live in Longwood which is about 10 miles north of Winter Park. I hope this doesn't verify but the models are indicating this possiblity. I've seen this disturbances come through like this before and we got unforeseen rain in cold air but this time it might be snow.


Only seen snow twice in Florida, once in Orlando in 1989 and 2006 in Tallahassee. Both looked like somebody blew little baby packing peanuts into the air. But I have never seen more than that.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting unf97:


Reedzone, it is a wait and see thing. Things can change so quickly with such an extreme pattern like this in which we are experiencing currently.

I am always skeptical about wintry precip in these parts, but I admit it certain factors come together, we may have some intersting weather around here this weekend.


I would love to see 2 inches here, nothing more, it's beautiful. I used to live on Long Island 8 years ago, as a kid, I loved the snow. It would be awesome to see some snow here. Hasn't happened in 20 years.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
703. unf97
Quoting reedzone:


Hey, I live in Palm Coast. I wonder if the GFS will back it west more and create a "Florida snowstorm".. Guess it's a wait and see thing, looks like a nor'easter right off our doorstep.


Reedzone, it is a wait and see thing. Things can change so quickly with such an extreme pattern like this in which we are experiencing currently.

I am always skeptical about wintry precip in these parts, but I admit if certain factors come together, we may have the potential for some interesting weather around here this weekend.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
701. PcolaDan
4:30 PM GMT on January 06, 2010
Where our oldest lives.

Forecast for Rapid City
Updated: 3:26 am MST on January 6, 2010
Winter Weather Advisory in effect until 5 am MST Thursday...
chancesnow
Today
Windy...cloudy. Snow in the morning...then chance of snow in the afternoon. Blowing snow in the morning...then areas of blowing snow in the afternoon. Snow accumulation around 1 inch. Highs around 8. Northwest winds 25 to 35 mph. Chance of snow 80 percent. Wind chill readings 17 below to 27 below zero.

Member Since: August 22, 2008 Posts: 12 Comments: 6010
699. conchygirl
4:29 PM GMT on January 06, 2010
So, I guess hope for warmer weather for the Disney Half Marathon on Saturday might be wishful thinking! Yikes, it is going to be cold.
Member Since: June 11, 2008 Posts: 24 Comments: 5910
698. reedzone
4:28 PM GMT on January 06, 2010
Quoting unf97:
Officially, the Jax NWS WFO recorded a moring low temperature of 21 degrees, which tied the record for this date.

They are just a few short miles from where I live, and I registered a morning low of 20.6 degrees. Makes sense the temps registered the same.

I did see the latest GFS runs and I dare not say what I saw, which is a possible storm brewing just off the NE FL coast, which definitely would make weather here in Jax exteremely interesting.

What a turnaround with the models for the past 24 hours.


Hey, I live in Palm Coast. I wonder if the GFS will back it west more and create a "Florida snowstorm".. Guess it's a wait and see thing, looks like a nor'easter right off our doorstep.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
697. unf97
4:26 PM GMT on January 06, 2010
Officially, the Jax NWS WFO recorded a moring low temperature of 21 degrees, which tied the record for this date, which was set in 1884!

They are just a few short miles from where I live, and I registered a morning low of 20.6 degrees. Makes sense the temps registered the same.

I did see the latest GFS runs and I can't believe what I saw, which is a possible storm brewing just off the NE FL coast, which definitely would make weather here in Jax exteremely interesting.

What a turnaround with the models for the past 24 hours.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
696. WxLogic
4:25 PM GMT on January 06, 2010
Quoting StormW:
Possible?
Look at Florida:
img src="gfs.snowcover" alt="" />


That'll sure be an interesting Saturday if it happens. I'll have my Camera ready just in case... hehe.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
695. TheCaneWhisperer
4:20 PM GMT on January 06, 2010
Quoting StormW:
Possible?
Look at Florida:
img src="gfs.snowcover" alt="" />


May have to take a short drive up north with the family if that comes to pass. Any chance of the snow line moving south of lake o a tad and east :-D ?
694. StormChaser81
4:19 PM GMT on January 06, 2010
Quoting Jeff9641:


The new GFS is looking a very much like snow will fall in C FL and for a good rate for a couple of hours or so.


Well if it does ill be about 10 miles north of Orlando in Winter Park Florida and ill take pictures and post them. That would be amazing. =)
Member Since: August 11, 2008 Posts: 0 Comments: 2315
693. jeffs713
4:18 PM GMT on January 06, 2010
Quoting Bordonaro:


On 12-27-09, when NWS DFW, TX started talking about Siberian Air and the Polar Vortex, it came a "big shock/surprise".

On 1-6-10, a whopping 10 calendar days since they mentioned this, HERE IT COMES!! Talking about a LOW NEAR 12F EARLY SAT. Now, I am beginning to think ALL the NWS offices in TX are probably being CONSERVATIVE with the morning lows. Might be single digits for N TX??

I don't think the NWS offices are being intentionally conservative with the temps. The wildcards right now are the positioning of the high, and also the shortwave coming in. If the shortwave comes in and spreads clouds like the Canadian is predicting, lows are higher. If it doesn't, like the GFS is predicting, lows are lower.

The NWS here in Houston has been following the GFS pretty closely, and actually extending out the super-cold low temps through Sunday. Also, keep in mind the most cold air is 24-36hr out, and exact numbers will be hard to pin down this far out.

edit- to clarify, by "exact numbers", I mean that right now, the NWS is using a range for low temps, and just putting down the midpoint. (for example, the low forecast for Friday night is "lows near 20")
Member Since: August 3, 2008 Posts: 16 Comments: 5882
692. reedzone
4:17 PM GMT on January 06, 2010
A classic "Nor'easter" type storm is off the Florida Coastline in 102 hours, the question is, how far west can the band of snow/wind get to the coastline. Very interesting weekend. Right off my doorstep!
Member Since: July 1, 2008 Posts: 13 Comments: 7390
690. mara0921
4:12 PM GMT on January 06, 2010
Good Morning. I recorded 32.7 F in Oakland Park, FL for a morning low on my digital thermometor. And was surprised to find that dew formed on top of that cars. This was around 7:15 AM that I went out to walk my dog and see how cold it was. Turned out that dew was frost, which was gone within 30 minutes. I imagine tonight if temps fall to same level then there will be a more widespread frost event even in metro broward countty. Anyoen else in broward see frost on their cars?
Member Since: November 23, 2009 Posts: 0 Comments: 19

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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.