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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Area snow fell in Florida on Jan 19, 1977

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1038. KEEPEROFTHEGATE (Mod)
evening all finally updated my blog and model runs
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting Bordonaro:


Siberian Express, Flight Number -35, will move into DFW, TX at Midnight tonight, continue into the Deep South and the Southeast US on Sat 1-9-10.

This one is worse than the first piece of Arctic air. The first Arctic front was like dropping 5 ice cubes into a tall glass of water. The SECOND front is like dropping a ton of ice into the backyard swimming pool in comparison. It's a large chunk, covering the Western Half of Canada.

And yes, they're may be a third Arctic outbreak earlier next week. This Arctic front is hauling real fast. And this is not normal by any means :0).


I'm afraid highs will have to be stripped for the weekend and the warming trend(or should I say moderating) delayed til the mi-end of next week before another arctic airmass(I think that mild break will just be the eye of the storm).

Quoting jrweatherman:
Drakoen 11:47 PM GMT on January 06, 2010
Yes, the GFS is forecasting for snow from Central to South Florida as the Arctic airmass dives southward allowing for cold air to mix with the precipitation. This forecast from the GFS appears to be the coldest and wettest.


It is hard to ignore the GFS when it has been consistent for many days. Local mets here in Tampa are all speculating. A common theme is that this type of event is difficult to forecast since it only happens every 30 years or so.


Also it's not just all the GFS members predicting snow for Orlando. But as others have chimed in, let's see if modals stay this consistent.

If that Low is in the right place at the right time, Florida could have a once in a lifetime snowstorm(but let's not get ahead of ourselves lol).
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1036. chawk
Just got home from work, Local Tampa news station is now calling for a 40% chance of sleet snow mix saturday and the coldest night yet to come Sunday.
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Here's a taste of what the Dallas-Ft Worth, TX area will experience from "Siberian Express, Flight # -35" over the next few days:

Wind Advisory
Special Weather Statement
Hazardous Weather Outlook



Tonight: A chance of rain before 3am, then a slight chance of freezing drizzle. Cloudy, with a low around 22. Windy, with a calm wind becoming north between 20 and 25 mph. Winds could gust as high as 40 mph. Chance of precipitation is 40%.

Thursday: Partly sunny and cold, with a steady temperature around 25. Windy, with a north wind between 20 and 30 mph, with gusts as high as 40 mph.

Thursday Night: Partly cloudy, with a low around 15. North wind between 10 and 15 mph, with gusts as high as 25 mph.

Friday: Mostly sunny and cold, with a high near 25. North northwest wind between 10 and 15 mph.

Friday Night: Mostly clear, with a low around 12. North northwest wind between 5 and 10 mph.

Saturday: Sunny, with a high near 34. North wind between 5 and 10 mph.

Saturday Night: Mostly clear, with a low around 17. North wind around 5 mph becoming south
Member Since: August 25, 2009 Posts: 20 Comments: 6785






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1033. aquak9
so much south/central florida taking a hit on agriculture...but it's all across the country.

carry on...
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Quoting aquak9:
heh heh heh unf...if it DOES snow in Jax, I'm gonna need a photographer, hahahahaha...


If you do receive some snow, I am sure your going to take some real good pictures.

Meanwhile the Siberian Blast is singing a new song for the US:

Member Since: August 25, 2009 Posts: 20 Comments: 6785
1031. unf97
Quoting aquak9:
heh heh heh unf...if it DOES snow in Jax, I'm gonna need a photographer, hahahahaha...


Yeah, O.K. LOL..
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yikes!

Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting unf97:


Oh yeah, absolutely. if we get any snow here in Jax area, I'll be happy to post picutres of the event, along with our other Florida bloggers.

But, again, I am tempering my enthusiasm because I know there will be changes to the model runs about this situaton.

We shall wait and see!

I agree with ya.. I will wait til its like 2 hours b4 time if we are indeed goin to get any snow or not.. I will b happy that we will, but im not going to get my hopes up to a thing that rarely happens in FL..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
1027. aquak9
heh heh heh unf...if it DOES snow in Jax, I'm gonna need a photographer, hahahahaha...
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1026. aquak9
good evening from the Porch'o'Blog. 38ยบ

unf and SSI- almost think if we were to have ANY chance of flurries, it's be more like after sunday day. But Gainesville and Ocala? not out of the question for thursday night.
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1025. unf97
Quoting FLPandhandleJG:


I agree with that.. im sure most of us will b happy and sum will not.. you cant please anyone in this world.. but i would love to c snow tho.. ;) i will post pictures on here if it does.. ;)


Oh yeah, absolutely. if we get any snow here in Jax area, I'll be happy to post picutres of the event, along with our other Florida bloggers.

But, again, I am tempering my enthusiasm because I know there will be changes to the model runs about this situation.

We shall wait and see!
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let me ask anyone this.. Ive been looking at GFS, NAM, and other models to just name a few.. and most of them have the moisture reaching the panhandle of FL by friday then thursday what are most of everyone is thinking at this point.. is it possible that it will come that late or you think it will switch back in forth until 12hours prior?
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Drakoen 11:47 PM GMT on January 06, 2010
Yes, the GFS is forecasting for snow from Central to South Florida as the Arctic airmass dives southward allowing for cold air to mix with the precipitation. This forecast from the GFS appears to be the coldest and wettest.


It is hard to ignore the GFS when it has been consistent for many days. Local mets here in Tampa are all speculating. A common theme is that this type of event is difficult to forecast since it only happens every 30 years or so.
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1022. Drakoen
Quoting StSimonsIslandGAGuy:
Drak how realistic is that cold and wet GFS run? snow for 18+ hours in central Florida is unprecedented. I don't believe that will really happen---but since many hours of that are at night, it implies accumulating snow in some places.

2" in Gainesville, Ocala or Orlando would be fun :)

I think we are too far north for snow though, here on the GA coast. The Friday morning event doesn't look like it will work out either.


It is not realistic in it's longevity but possible in the idea of wintry precip.
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Quoting unf97:
This situation with the wintry precip forecast in FL is an ever changing situation. It's the perfect wait and see component for forecasting. But it is fun speculating what will happen that is for sure. So very rare even thinking about this for Florida.

However, with this extreme pattern, if it is going to happen, this is the type of set-up. Again, it's all about timing.


I agree with that.. im sure most of us will b happy and sum will not.. you cant please anyone in this world.. but i would love to c snow tho.. ;) i will post pictures on here if it does.. ;)
Member Since: August 15, 2008 Posts: 0 Comments: 2133
1020. Drakoen
Quoting IKE:
Tallahassee weather office is saying no snow for NW FL....Mobile,AL. office is saying yes to Okaloosa...Santa Rosa and Escambia counties of NW FL.

Someone is going to be right....vice versa....


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.
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1019. unf97
This situation with the wintry precip forecast in FL is an ever changing situation. It's the perfect wait and see component for forecasting. But it is fun speculating what will happen that is for sure. So very rare even thinking about this for Florida.

However, with this extreme pattern, if it is going to happen, this is the type of set-up. Again, it's all about timing.
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heres what NOAA says about me in Niceville FL thursday day and night..

Thursday: Rain likely, mainly after noon. Cloudy, with a high near 52. Wind chill values between 15 and 25 early. North wind between 5 and 15 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.

Thursday Night: A 50 percent chance of snow before midnight. Cloudy, with a low around 27. Wind chill values between 20 and 25. Blustery, with a north wind between 15 and 20 mph, with gusts as high as 25 mph. New snow accumulation of less than a half inch possible.
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Took at look at the GFS 18Z run maps. Intersting set up for some wintry precip in parts of FL, however, I am not ready to jump on the bandwagon and call for a SE US/FL snowstorm, yet.

The next 3 or 4 runs ought to be interesting.

However, Siberian Blast, Flight # -35 is proceeding south and eastward, and will arrive "on time". It is gonna get REAL COLD for the S Plains, Deep South, into FL for the next few days.

Looks like a moderating trend and a return to the Arctic Blast at around Day 14?
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting GBguy88:


I'd really like to see some...but not counting chickens before they hatch. Checked the NOAA site as opposed to this one, and their forecast changed to include the possibility of light accumulation. I don't think anyone really has a precise idea on this one.


ya thats y u check back every now and then b/c anything can change.. and plus its harder to predict this type of weather for the south, b/c usually dont c it that much unless u get an artic blast like this and some percipitation.. we got all the ingredients but just depends where L develop and how far south or how close to the gulf coast..
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1014. GBguy88
Quoting IKE:
Andalusia,AL.....

Thursday Night: A 40 percent chance of snow before midnight. Cloudy, with a low around 22. Wind chill values between 15 and 20. North wind between 10 and 15 mph, with gusts as high as 20 mph. New snow accumulation of around an inch possible.


Mobile,AL....New snow accumulation of less than a half inch possible.




The system in December was supposed to bring a dusting to an inch, and all we had was a nice wet rain with about 10 minutes of sleet mixed in. I always get hyped up beforehand, and then let down when nothing happens...trying a new approach ;)
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1013. IKE
Tallahassee weather office is saying no snow for NW FL....Mobile,AL. office is saying yes to Okaloosa...Santa Rosa and Escambia counties of NW FL.

Someone is going to be right....vice versa....
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Quoting PensacolaDoug:
I'll believe it when I see it. Meanwhile check out the 18Z GFS, It has another phantom snow storm for the gulf coast at about 256 hrs or so.

looks like they showing a smaller artic blast close to North FL up and sum midwest to east coast.. but thats like 324hours out.. but u never know.. that could b another system to be looking at in the future but right now its not as bad as this artic plunge/so called snowstorm.. but everything changes tho.. ;)
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1011. IKE
Quoting WPBHurricane05:


Have fun.



LOL.
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1010. IKE
Andalusia,AL.....

Thursday Night: A 40 percent chance of snow before midnight. Cloudy, with a low around 22. Wind chill values between 15 and 20. North wind between 10 and 15 mph, with gusts as high as 20 mph. New snow accumulation of around an inch possible.


Mobile,AL....New snow accumulation of less than a half inch possible.


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It's all about the timing of the precipitation. If you get precip during your daily MAX, chances are it's not gonna snow. If it hits during your MIN, you have a better chance, so if the line goes through your area in the middle of the day your chances of seeing snow/mix are not AS great as if it moves through your area at night, or during you temp MIN.
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Quoting IKE:


Look at this for Crestview,FL...WTH?????????


Thursday Night: A 50 percent chance of snow before midnight. Cloudy, with a low around 23. Wind chill values between 15 and 20. North wind between 10 and 15 mph, with gusts as high as 20 mph. New snow accumulation of less than a half inch possible.


Have fun.

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1007. Drakoen
Yes, the GFS is forecasting for snow from Central to South Florida as the Arctic airmass dives southward allowing for cold air to mix with the precipitation. This forecast from the GFS appears to be the coldest and wettest.
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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?
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1005. GBguy88
Quoting FLPandhandleJG:


They probably went by the local mets in Pensacola saying 50% of chance.. but now they raised it to 70% of chance for thursday.. but didnt say what type of percipitation.. but those mets say its a possibility.. I believe we will get something or more.. and Fl better watch out if this L brings alot moisture or not.. depends how close it gets to the coast or not.. but anyways it would be alot of problems no matter what.. But I agree with Tampaspin and Bondonaro, that we will c sum snow or more.. we just got to check up on it, b/c it could change rapidly!


I'd really like to see some...but not counting chickens before they hatch. Checked the NOAA site as opposed to this one, and their forecast changed to include the possibility of light accumulation. I don't think anyone really has a precise idea on this one.
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Siberian air walled up against the Rockies now. Arctic air heading south and east:

Member Since: August 25, 2009 Posts: 20 Comments: 6785
1003. IKE
Quoting PensacolaDoug:
I'll believe it when I see it. Meanwhile check out the 18Z GFS, It has another phantom snow storm for the gulf coast at about 256 hrs or so.


Look at this for Crestview,FL...WTH?????????


Thursday Night: A 50 percent chance of snow before midnight. Cloudy, with a low around 23. Wind chill values between 15 and 20. North wind between 10 and 15 mph, with gusts as high as 20 mph. New snow accumulation of less than a half inch possible.
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I have to drive back all day Saturday from TN to South FL I hope I don't get caught in an icy mess, not fun to drive in...
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Quoting StSimonsIslandGAGuy:
Jedkins those GFS maps I put up would be pretty awesome if they verified :)


yeah I know!

All the local MET's are saying as rare as it is, dont be suprised to see some sleet or snow flakes this weekend>

That sounds like they are pretty confident that we will at least see a few flakes, which is pretty darn crazy, the mentioned high temps may not even reach 40 all weekend with mid 20's at night! this is gonna be something else!
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I'll believe it when I see it. Meanwhile check out the 18Z GFS, It has another phantom snow storm for the gulf coast at about 256 hrs or so.
Member Since: July 25, 2006 Posts: 0 Comments: 553
Quoting GBguy88:


If it snows in Central/South Florida and not up here, I'll be...well, I don't know, but not happy. I'll probably try to ride up to Montgomery if snow is out of the question here. I will see it tomorrow if it kills me :)

ya but driving in that nasty rain/sleet/snow mix isnt fun or heavy snow.. or maybe icy conditions.. its no fun.. be careful if u decide or not!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting JGreco:
They just changed the forecast for Pensacola on Thursday night...went from a 50% chance of snow to being all rain with a slight chance of sleet. I think this will be a big non-event for the panhandle...

The forecast for Fort Walton Beach according to the NOAA website still stands for Thursday night with a 50% chance of snow. I don't know where you got your forecast from. It seems odd that we get only rain up here in the panhandle and there are talks of a significant snow event for Central Florida. Can anybody explain the weather dynamics for this.


They probably went by the local mets in Pensacola saying 50% of chance.. but now they raised it to 70% of chance for thursday.. but didnt say what type of percipitation.. but those mets say its a possibility.. I believe we will get something or more.. and Fl better watch out if this L brings alot moisture or not.. depends how close it gets to the coast or not.. but anyways it would be alot of problems no matter what.. But I agree with Tampaspin and Bondonaro, that we will c sum snow or more.. we just got to check up on it, b/c it could change rapidly!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting PensacolaDoug:


Big surprise there! Thats how it aways works out down here. Wouldn't it be something if they get it in central part of the state?


If it snows in Central/South Florida and not up here, I'll be...well, I don't know, but not happy. I'll probably try to ride up to Montgomery if snow is out of the question here. I will see it tomorrow if it kills me :)
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They just changed the forecast for Pensacola on Thursday night...went from a 50% chance of snow to being all rain with a slight chance of sleet. I think this will be a big non-event for the panhandle...

The forecast for Fort Walton Beach according to the NOAA website still stands for Thursday night with a 50% chance of snow. I don't know where you got your forecast from. It seems odd that we get only rain up here in the panhandle and there are talks of a significant snow event for Central Florida. Can anybody explain the weather dynamics for this.
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Way back at #969. Apologize if there was any confusion. Presslord answered my "inferred" question...asked in a rather obscure way. My bad.
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994. unf97
Quoting tampahurricane:
all the local news stations for the Tampa area are talking about possible snow now so it looks like a pretty good chance.


Remember this is a highly uncertain forecast. The models can and will likely change with this. Stay tuned!
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993. unf97
Quoting FLPandhandleJG:

could b possible.. we will c ;)


yes, it all depends on where the low forms. This can change with the model runs of course.
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Quoting FLPandhandleJG:

could b possible.. we will c ;)


Albeit I despise cold weather, it would be interesting to see snow here in St lucie county.
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all the local news stations for the Tampa area are talking about possible snow now so it looks like a pretty good chance.
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Greetings.
The weather here in the Southern Carib. Islands is getting very dry, very fast.
First wave of Sahara Dust is clearly evident this week, and the winds are gusting to 25 mph. Heavy surf conditions last week damaged coastal infrastructure, and the the wind 'feels' like April.
Looks to be a long, hard dry season coming... Nov. and Dec. rains were very short of average. The trees are losing leaves fast.
Temps very pleasant at 76 min and 82 max. But water is going to be a real issue in a few short months.
Sorry to see that it is a dread cold time for so many people in so many areas.
Glad I am not there!!
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If it did snow in Central/South Florida, with all the crazy drivers we have FHP would be working overtime.
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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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