NHC Cone of Uncertainty For After 3 Days Is Not Helpful

[gatorcane]

I know the NHC is working hard to keep us safe, but when a cone of uncertainty is sometimes 300+ miles (it's even larger as a storm is approaching the coast at an angle) for the 3-5 day track, to me that isn't helping much at all. Then we have seen multiple times when they ordered an evacuation and then a day later they rescind it. The FL Keys were hit hard last year economically by all of the close calls and evacuation orders even though none of the 4 storms came anywhere close to them. Furthermore, last year Charley just barely made it into their forecast cone and Ivan went way farther west than they originally thought. I think the NHC should stick to a 3 day maximum track because their forecasting is not accurate enough after that and it can be more costly than effective.

Comments welcome.

[x-y-no]

I think the 3-5 day track and cone is valuable. Generally, evacuations aren't ordered that far out (the partial evacuation of the upper Keys in the face of Ivan was an exception because of the difficulty of doing a full evacuation there and the extreme strength of the storm - cat 5 at that time) but officials and general population can get a heads-up that preliminary preparations are called for.

Jan

[Derek Ortt]

Charley would have leveled Key West had it not have been the smallest Atlantic hurricane in recent memory. If you were not in the eye wall, you basically received nothing. Remember, Charley passed just 10 miles west of Havana, leveling the western subarbs, but leaving the center of the city untouched

[wxman57]

The 4-5 day cone is basically an extrapolation of the 3-day cone. The 3-day cone in no way represents any confidence or lack of confidence in a forecat track. It simply represents a 10-year average error either side of the track. Basically, it represents a 60% likelihood that the storm will be within that cone at each time period. (I believe it's 60 and not 70). So as big as the cone is, 40% of storms in the past 10 years were outside the cone at any time along the track.

Unfortunately (for the public), there's no way for the NHC to represent that they have more or less confidence in a forecast track. The cone is the same for a storm that's stalled and they haven't a clue where it'll be in 5 days as for a storm tracking along at 20 mph in a strong steering flow. On the other hand, it's great for private weather providers who aren't bound by such rules. We can narrow or expand the cone as we wish, conveying our confidence in the forecast track. It's possible we could even display a track with 2 cones - one along the current forecast track and another lobe in a different direction if there's a chance that a storm may turn sharply at some location.

[vacanechaser]

I will disagree with you boca_chris... I did not pay much attention to it last year due to all the activity and being on the road so much, however, the "5 day" cone was right on the money with Isabel.. Besides the 5 day forecast is more or less for the military..

Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

[gatorcane]

But what is the real value in showing a track after 3 days? Evacuations and preparations can be done easily in less than 3 days. That's the whole point of having a projected track right? Anything after 3 days to me is not necessary and can lead to confusion.

[senorpepr]

The need for the extended forecast is needed for many reasons. Just to name a few, emergency centers have an extra 48 hours with the extended cone to prepare before a full evacuation is ordered. The public can also utilize this for the same reason. When residents are in the cone that far out, they can get their personal orders prepared before the evacuation process fully begins. But, as Jesse mentioned, the military really needs this data. Navy ships needs that extra time to change course and get out of harms way. Land bases also need the extra time to prepare to protect billions of dollars in assets. The idea is not to confuse people nor to get people to fully exacuation, but to begin to prepare -- to be on alert.

-Mike

[gatorcane]

Yes, I understand the military piece. But as far as preparations are concerned, if everybody would do them (as they should) long before a hurricane threatens than 3 days is enough.

[cyclonaut]

Yeah I remember the 1st advisory on Frances...the 5 day forecast had Frances right over Miami as a CAT 4..then that changed a few times before it settled in on the Ft.Pierce area.I have mixed emotions on this subject.One of the problems I find with it is that it stirs up alot of frenzy..it makes the storm seem closer than what it really is.The news media goes berzerk before storms even reach the islands & god help us when that 5 day plot has it aimed @ your city or mine.Home Depot may love the premature hype but I would just prefer they go back to just the 3 day forecast.

[gatorcane]

Thank you Cyclonaut for your thoughts. I knew there had to be somebody on my side on this one. The 5 day forecast is way too premature. Look at the forecast cone! Typically it's spans more than 300 miles! It causes people to do unnecessary things and panic for no reason. Three days is enough. There's no reason why we can't be ready within 72 hours.

[gatorcane]

I will add that many times I would be vacationing in the Keys and they would order an evacuation only to find out that the storm had turned north (as they always do).

[gatorcane]

well not always but usually.

[Rainband]

Anyone who has been studying storms for any length of time realizes not to pay attention to a thin line. Anyone who watched the news last year realizes that too.....or at last they should.

[Scorpion]

I like the 5 day forecast. If people can't figure out that it is just a broad estimate they need to get their brain checked. I see it as a broad consensus of where the storm might head. If I see the track pointed in the general direction of west for example, and the storm is in the Atlantic, I will be very alert.

[gatorcane]

yes, that is great with the storm is 2000 miles away in the Atlantic. But when it gets closer, the 5 day track creates more confusion because usually it is wrong. The closer the storm gets to land, the more variables are involved. Troughs, dry air infusion, High pressure variance etc.

[gatorcane]

Maybe a compromise is needed. We use 5 day tracks when the storm is farther than X miles from land (where X miles is a pre-determined distance). This rule will let us know well in advance that a storm is headed in the general direction of the US (and not a fish storm). Once we are less than X miles than a 3 day track is used. I say X should be 500 miles. Sorry I'm an Engineering major...lots of math in my career. lol. Comments welcome.

[senorpepr]

I still disagree. I still believe that the five-day forecast should remain. Even if the system is approaching land, the five-day forecast can put up on synoptic-scale features such as troughs that can steer cyclones from one state to another. This leads back to better preperation. You can't assume that everyone is already prepared for a storm before the season begins. Furthermore, even if you are prepared, to have the extra 48 hours to insure things are in order to very helpful. There's no need in getting rid of it. It a 120-hour forecast is confusing for people, a 72-hour forecast shouldn't be any less confusing. If I'm not mistaken, the margin of error used for the 120hr point is extrapolated from the 72hr error-window.

[cyclonaut]

I like the 5 day forecast. If people can't figure out that it is just a broad estimate they need to get their brain checked. I see it as a broad consensus of where the storm might head. If I see the track pointed in the general direction of west for example, and the storm is in the Atlantic, I will be very alert.

I have always been alert when there is something out there moving generally west..I dont need a 5 day forecast for that.

I don't care if they keep or throw it out!However(**goes off on a rant**) IMO,the general public like the media & the average person that does'nt follow the tropics as closely as you & I take that 5 day forecast & cause asemi-panic..The local news media in my area were in a feeding frenzy last season with every storm the appeared to be a threat.A entire week + before the hurricane was even suppose to be in our vicinity the news was reporting from Home Depot & Publix talking about people that were buying supplies.To me it felt like the storm was 2-3 days way instead of 7.

Evacuating the Keys for what turns out to be no reason is going to come back & bite someone in the rear.I have heard talk about people not leaving the next time because of these false alarms.Those are some of the glitches I see but its nothing I lose sleep over.

[Rainband]

yes, that is great with the storm is 2000 miles away in the Atlantic. But when it gets closer, the 5 day track creates more confusion because usually it is wrong. The closer the storm gets to land, the more variables are involved. Troughs, dry air infusion, High pressure variance etc.

I disagree. The cone is usually verified.

[wlfpack81]

I think the 5-day cone should stay as well. It's not so much the NHC/NOAA's fault as it's the freaking media's fault for overhyping in order to get the better ratings for the 11pm news slot. The NHC even says that 5 days out there will be so much error yet the media as someone gave an example of will take a storm 7 days out and create the mass panic in the given vicinity.