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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its 35 degrees at my house in Pinellas which is just west of Tampa.
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Quoting presslord:


Excellent!!!!!!!!!!!!!!!!!!!!


Yea Press, get some of that. Every once in a while I have to show off my meteorological skilz. LOL
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Here's a WU SST update for today:



Cyclone Seven has formed in the Indian Ocean, and the western flank is tapping into warm 30C water. The storm will remain over these warm waters for several days, likely to allow the storm to strengthen and become larger in size, and the cyclone's western flank is currently experiencing a flare-up.

The warm 30C+ region of the ENSO warm pool is funelling in two directions: toward the South Pacific warm pool (toward the Ross Ice Shelf and Antarctica) and toward the southeast (Chile Humboldt cut-off). The good news with the Humboldt cold current is that the southeastern 20C limit of the greater ENSO warm pool has not advanced toward the Chilean coast in the past week. The bad news is that the both the length of the current and the width have diminished over the past few days.

Meanwhile, the warm area west of Spitsbergen has warmed to 14C at its center, while the Norwegion section of the Gulf Stream keeps retreating. The warm anomalies indicate a possible diversion toward western Greenland, where generally ice-free SSTs have advanced past Jakobshavn Isbrae.



Member Since: August 30, 2008 Posts: 8 Comments: 2835
1127. doabarrelroll 2:41 AM GMT on January 07, 2010
Quoting jrweatherman:
1116. BahaHurican 2:25 AM GMT on January 07, 2010
Anybody in the Central / South area of FL still "expecting" snow? It looks like the models and mets have backed off the possibility big-time....at least for this particular cold weather event.

Which models have "backed off"? The GFS is still very bullish on frozen precip for Central to South Central FL.


how about north central florida


Looks like the GFS wants to bring frozen precipitation to about the Gainesville area. Also, a little bit in the Tallahasse area. I think we'll have a much better idea this time tomorrow night.
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SnowCoverLoop

heres another good one if u like.. I still cant find a good GFS snow cover map..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Evening Wunderfolks.
Record Broken in Daytona today.
Record Report
Statement as of 4:42 PM EST on January 06, 2010
... Record low temperature set at Daytona Beach... a record low temperature of 28 degrees was set at Daytona Beach this morning. This breaks the old record of 30 set in 1999.

Current conditions:
Daytona Beach (Ponce Inlet), FL, Daytona Beach, Florida (PWS) Updated: 11 sec ago
30.6 %uFFFDF Clear
Windchill: 31 %uFFFDF
Humidity: 78%
Dew Point: 25 %uFFFDF
Wind: 0.0 mphfrom the WSW
Wind Gust: 0.0 mph
Pressure: 30.21 in (Rising)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds: Clear -
(Above Ground Level)
Elevation: 12 ft
Turning in. Have a nice evening everyone.


Member Since: July 11, 2006 Posts: 14 Comments: 11356
Does anybody know what % chance Mobile has of getting snow Thursday night?
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Quoting weatherbro:


Don't know what you mean. The modals still say the same thing. And around Orlando the mets are still talking about the potential snow.

isnt the new models supposed to come out soon or later? idk when they update the models.. i forget.. i know they do it a few times a day..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting BahaHurican:
Anybody in the Central / South area of FL still "expecting" snow? It looks like the models and mets have backed off the possibility big-time....at least for this particular cold weather event.


Don't know what you mean. The modals still say the same thing. And around Orlando the mets are still talking about the potential snow.
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Quoting Chucktown:


We're going with a slight chance on Friday morning. Looks like maybe just a few flurries if the arctic air can get in here quick enough. We're gonna get to 50 tomorrow, so the boundary layer is going to be too warm for snow until very early Friday morning. The next system on Saturday morning looks to be too far south and east before it really "bombs" well offshore. The entire column will definitely be below freezing by Saturday morning but no moisture for dendritic ice crystal growth (snow).


Excellent!!!!!!!!!!!!!!!!!!!!
Member Since: August 13, 2007 Posts: 0 Comments: 10492
Quoting Portlight:
Chuck...You're saying no Holy City snow?


We're going with a slight chance on Friday morning. Looks like maybe just a few flurries if the arctic air can get in here quick enough. We're gonna get to 50 tomorrow, so the boundary layer is going to be too warm for snow until very early Friday morning. The next system on Saturday morning looks to be too far south and east before it really "bombs" well offshore. The entire column will definitely be below freezing by Saturday morning but no moisture for dendritic ice crystal growth (snow).
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Quoting BahaHurican:
Something else I'm remembering by looking at today's temps is how small our diurnal range usually is. We got up to 69 today. Our record LOW for today is only 57, which is only 2 degrees cooler than we are now. It seems we rarely range much more than 12 degrees between daily highs and lows, from my quick look back at recent temp records.

Big contrast with places in the US where it can be 70 in the day - and 35 at night!


Tallahassee is like that especially in September. It the low can be 49 and the high can be 82-83.
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1116. BahaHurican 2:25 AM GMT on January 07, 2010
Anybody in the Central / South area of FL still "expecting" snow? It looks like the models and mets have backed off the possibility big-time....at least for this particular cold weather event.


Which models have "backed off"? The GFS is still very bullish on frozen precip for Central to South Central FL.
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Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting BahaHurican:
Anybody in the Central / South area of FL still "expecting" snow? It looks like the models and mets have backed off the possibility big-time....at least for this particular cold weather event.


I hope not. I bought gloves and a ruler (with millimeters) to measure any potential snowfall.

I guess we won't really know till Saturday.
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So is the rain in front of this cold air supposed to be bad? Im in SELA. The rain should start tomorrow.
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Quoting tornadodude:


hey there, um I'm expecting 5-6 inches, hopefully you will get some snow!

I sure hope so.. but most the models i check have the percipitation coming in mostly on friday.. and maybe sum showers sat and sun b/c sum moisture could hug the coast of the panhandle.. but the weekend is a big IF.. But I believe they might have to extend the forecast.. any thoughts from u or anyone else? or am im seeing this wrong or the models might flip flop again b/c of a possible rare event that could happen?
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1120. Ossqss
Howdy, stumbled across a site packed with some free media/documentaries and stuff and thought I would share it. I missed the beginning of a show on the science channel and found the whole thing on the site linked. :)

L8R

http://factualtv.com/documentary/The-Crystal-Ocean
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Chuck...You're saying no Holy City snow?
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Member Since: July 25, 2006 Posts: 0 Comments: 575
I think we will see Pinellas County go under a freeze warning during the 11 o'clock news.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Anybody in the Central / South area of FL still "expecting" snow? It looks like the models and mets have backed off the possibility big-time....at least for this particular cold weather event.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
Something else I'm remembering by looking at today's temps is how small our diurnal range usually is. We got up to 69 today. Our record LOW for today is only 57, which is only 2 degrees cooler than we are now. It seems we rarely range much more than 12 degrees between daily highs and lows, from my quick look back at recent temp records.

Big contrast with places in the US where it can be 70 in the day - and 35 at night!
Member Since: October 25, 2005 Posts: 19 Comments: 22322
Quoting GTcooliebai:

No I'm talking about when temps are near freezing. I think the winds have to calm down and there has to be high humidity.


Humidity doesn't have to be all that high - I have seen frost form with a temp below freezing and a dewpoint near 0. Frost can actually form when the air temperature is above 32. The proper height to read the air temperature is 4-6 feet above the ground, but cold air being more dense than warm air tends to settle along the ground. Sometimes you will see an official low temperature being recorded as 34 or 35 degrees, but still a widespread frost had occurred becuse it was at freezing right along the ground.
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Quoting FLPandhandleJG:

Hey Tornadodude.. how r u doing.. and how much u expecting from the snow storm..hopefully i can get sum snow in the fl panhandle.. but right now its a wait and c.. just my opinion..


hey there, um I'm expecting 5-6 inches, hopefully you will get some snow!
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1112. GBguy88
Well...I think I'll go ahead and call this a non-event for the Pensacola area. Call me crazy or a downcaster or whatever you may. Guess I better fill the tank for a ride to mid-Alabama tomorrow...thank goodness for 32mpg and a $1000 set of tires.
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Quoting tornadodude:
If that band across Missouri and Kansas moves across me, I would be quite happy (:


Hey Tornadodude.. how r u doing.. and how much u expecting from the snow storm..hopefully i can get sum snow in the fl panhandle.. but right now its a wait and c.. just my opinion..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Nassau @ 9 p.m. Airport reports 59; outside my door, 59. But it is "sticky".... forecast low for tonight is only 59, but I think it will get lower than that. The skies are clear, so nothing to keep temps from plummeting, and it's already 59....

Member Since: October 25, 2005 Posts: 19 Comments: 22322
If that band across Missouri and Kansas moves across me, I would be quite happy (:

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Quoting tornadodude:
good evening


Are you enjoying your snow? My anemometer got "broken in" today, was the breeziest day since Christmas Day, gusts up near 20MPH out of the SE. About midnight tonight, it will get a "real, good workout", NW winds of 20MPH gusts to 40MPH+.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Chucktown:


condensation forms - best example is fog

No I'm talking about when temps are near freezing. I think the winds have to calm down and there has to be high humidity.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
1106. unf97
It is now just below the freeze mark here. Currently 31.8 degrees.
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Quoting GTcooliebai:
Is it true when the actual air temp. and dew point are the same frost forms?


condensation forms - best example is fog
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Quoting VAbeachhurricanes:


haha its ok :) thanks for checkin


no problem.. i will try to get it from sum1 soon.. hope tampaspin or some1 has it.. I know for sure tampaspin unless i stumble upon it..
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1103. IKE
Quoting nrtiwlnvragn:


Link


Thanks...you always provide excellent information and links.
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good evening
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Quoting FLPandhandleJG:


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!


haha its ok :) thanks for checkin
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Is it true when the actual air temp. and dew point are the same frost forms?
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Can someone please post a link to the latest models. Are we suppose to get snow in West Palm Beach? Waht is going on? If someone could please post a detailed explanation and what models are forecasting this event to happen? This is very exciting!!!
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Thursday Night: Snow likely, mainly after midnight. Mostly cloudy, with a low around 29. West wind between 5 and 10 mph. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.

I have to drive from NC to Cincinnati on Friday. ARGH!
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1097. eddye
i say 50 percent chance of snow in se fl
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Quoting IKE:
Does anyone on here know how I can go back and get the moonrise for my location on January 1st?


Link
Member Since: September 23, 2005 Posts: 14 Comments: 11215
Quoting mara0921:
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?


less than 1% chance
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Quoting weatherbro:


Eh...But this isn't a long range(10 or even 7 day) forecast. If models do change, the snow belt will probably be to the north or south of where they currently expect it to be(based on how models performed in the past for events unfolding in about 3 days).

The good news is models seem to be handling this system better(as opposed to 12-24 hours ago).


ya finally.. but most models having the moisture come in on thursday night into friday into FL panhandle then move east, then east northeast when hits near east coast of central FL.. but if it does snow great if it doesnt then it wasnt meant to be.. but right now im not going to guess yet until that L forms.. I do c the storm from the midwest coming more to the south more as the artic air comes south.. I have a feeling theres goin to b alot more moisture with this system when the L forms..
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Largo Fl, Largo, Florida (PWS)
Updated: 3 min 23 sec ago
36.1 °F
Clear
Windchill: 36 °F
Humidity: 96%
Dew Point: 35 °F
Wind: Calm
Pressure: 30.19 in (Rising)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds: Clear -
(Above Ground Level)
Elevation: 40 ft

Member Since: August 31, 2009 Posts: 0 Comments: 5628
1092. IKE
Does anyone on here know how I can go back and get the moonrise for my location on January 1st?
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Quoting FLPandhandleJG:


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.. ;)


Eh...But this isn't a long range(10 or even 7 day) forecast. If models do change, the snow belt will probably be to the north or south of where they currently expect it to be(based on how models performed in the past for events unfolding in about 3 days).

The good news is models seem to be handling this system better(as opposed to 12-24 hours ago).
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its droppin again.. hmm
Member Since: August 15, 2008 Posts: 0 Comments: 2133
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?
Member Since: November 23, 2009 Posts: 0 Comments: 19

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.