NHC forecast 6-7 days out to be kept secret from the public.

[Decomdoug]

Did anyone notice this one in the Sun-Sentinel today by Ken Kaye?

"Hurricane center to develop six- and seven-day forecasts again this year. It also plans to do a better job keeping them secret, as they leaked out to the public last year, cutting the experiment short."

http://www.sun-sentinel.com/news/weathe ... 9056.story

I'm not sure if this is a blessing or not considering the margin of error that far out.

[CrazyC83]

How and when was it leaked? I don't remember that...

I agree, 7 day forecasts have way too large a margin of error and way too much panic potential over such a huge area.

[HurricaneBelle]

I often see references to the 6-7 day forecast in various AFDs and the HPC's 5-7 day outlooks, so that would be once place to get wind of them.

[StarmanHDB]

I hate to say it, but living in Broward County, I've learned to hold almost everything that the Sun Sentinel prints regarding tropical weather suspect. They tend to lean too much on the sensational side.

[MGC]

Still can't forecast the weather with 100% accuracy one day out.......margin of error at 7 days is what?...MGC

[JonathanBelles]

Still can't forecast the weather with 100% accuracy one day out.......margin of error at 7 days is what?...MGC

When the 7-day cone is released in 2-3 years, its 66% probability cone will probably have the same radius at 7 days as the 2000 66% probability cone at 3 to 5 days. I wasn't able to find exact numbers on the radii over the years, so this is just a hunch. I am somewhat supportive of the expansion to 7 days to match the common 7 day forecast seen on the evening news as long as we can be sure that a) a good majority of people actually understand the cone and its uncertainty and b) errors are indeed similar to track errors of less than 10 years ago.

[Hurricanehink]

IDK, there was a big hubbub about 5 day forecasts when they came out for the same rationale. FWIW, last year's 5-day forecast error in the Atlantic was 250 miles, which is 60 miles less than what the 3-day forecast error was in 1990. Also, last year's 5-day intensity error was identical to what the 3-day intensity error. I think going on to 7 days is a great decision. BTW, they've gotten better as well in the EPAC.

[wxman57]

The 7 day fcsts showed up in the model runs, I believe. Although that's a bit far out for the general public, some companies need to take actions that far out

[RL3AO]

I believe the NHC mentioned this in that pdf document showing the changes this year that was released back in February.

[CrazyC83]

With a 7-day cone, people also need to know that it is so far out and there is a good chance of things changing. Sensationalism could set in and people could go overboard, like evacuate a week out.

Somewhat related but different - if a major populated area is threatened by a large and destructive hurricane, would it make sense to put out a Hurricane Watch 72 hours out?

[psyclone]

I'm going to enjoy the lack of a 7 day cone for as long as it lasts. The five day is enough of a mess.

[weatherwindow]

With a 7-day cone, people also need to know that it is so far out and there is a good chance of things changing. Sensationalism could set in and people could go overboard, like evacuate a week out.

Somewhat related but different - if a major populated area is threatened by a large and destructive hurricane, would it make sense to put out a Hurricane Watch 72 hours out?

.........Some areas with high evacuation clearance times would benefit from a 72 hour Hurricane Watch.....as a Keys resident, it would make emminent sense.....rich

[RL3AO]

Hows this for an idea. Past day five they do track only. Intensity skill just isn't there.

[brunota2003]

The main problem is people freaking out because they are in the "7-day cone". 5 to 7 days should be seen as a "keep an eye out, it could head your way, also review your evacuation plans an family safety proceedures". 3 to 5 days should be seen as the "start your prep plans and continue to keep an eye out". The inside 3 day come should be "finish your prepping and evacuate if going to" (subject to change of course if you live in an area that evacs early, or an area that takes longer to evac from).

[MGC]

Well.......on Friday August 26, 2005 at 5am, I was not even close to the cone.....by 5pm I was near dead center. Monday morning August 29th 2005 began my hell on Earth.

You can embrace the 7 day cone if you wish.....I'm still sticking with the 2-3 day cone.

Once bitten.....twice shy.........MGC

[thegreatdr]

In the case of Katrina, the days 7 forecast was close to the Mouth of Mississippi river, before NHC shifted the points eastward from days 3-6, so I wouldn't be overly concerned. Just keep in mind what the error is, and all is fine.

NHC has been coordinating days 6 and 7 points with HPC since 2004, when HPC extended the range of their medium range progs to day 7. They only started keeping track of the information and verifying it a few years ago, from what I understand. Those that think the what you get on the HPC maps is exactly what NHC wants are in for a surprise. Since NHC does not publicly release their forecast, and HPC does and verifies the forecast when its near the United States with their pressure verification, it's ultimately HPC's say about the points, using NHC input. There can be haggling involved, but this won't change the points NHC prepared for the call. They never stopped doing the points last year for the 17z coordination call. Whether or not they placed them into ATCF is another matter. They know about the ftp website information leak, and have been working to try to resolve that prior to advisory issuance.

Sometime in the next few years the plan is to extended medium range to days 8-10, with day 8 possibly coming by next year. Once this happens, the coordination call will naturally be extended out to that range.

[LSU2001]

In my experience the best place to be is dead center of the 7 day cone. If I am in the bulls eye that far out I can pretty much bet that by the time the two day cone is settled my location will out of the cone. I am well aware that this is not always the case but with the margin of error that far out I figure it is a pretty high percentage bet.
tim

[Cyclenall]

In the case of Katrina, the days 7 forecast was close to the Mouth of Mississippi river, before NHC shifted the points eastward from days 3-6, so I wouldn't be overly concerned. Just keep in mind what the error is, and all is fine.

If you saw the 7 day forecast of Katrina, recreate it and post it here .

They know about the ftp website information leak, and have been working to try to resolve that prior to advisory issuance.

I think they should just leave it open for everyone who wants to see it, and stress that its "unofficial". The more open the better.

In my experience the best place to be is dead center of the 7 day cone. If I am in the bulls eye that far out I can pretty much bet that by the time the two day cone is settled my location will out of the cone.

Being dead center of the cone does not increase nor decrease the chances of being hit but since any given point is very low for being hit, it just seems that way. You have access to the 7 day cone, link with access password please .

[Chacor]

Yes, mathematically speaking the chances of being hit if you're dead centre of the 7 day cone or right on the edge are exactly the same.