Question...

[wx247]

I was reading another thread here today and I was wondering what the exact changes were from last year to this year? Five day forecasts now? In the past they were three day ones, correct?

Thanks!
Garrett

[Guest]

Yeah official forecast were only three day. I think the new format will be official 5 day forecast.

Experts - your comments!

PMH

[ColdFront77]

If we don't see a new format in the new five day forecast, then we will apparently see "larger cones" with the new method.

The 72 hour (three day) forecasts had quite a margin of error beyond the first 24 to 48 hours. We shall see how the graphics indicate these five day forecasts.

[chadtm80]

Any idea what prompted the change?

[Guest]

Thanks for the post Coldfront (Tom) - I agree the degree of error on the three day wasn't anything to write home about - and now the five day - we shall see. Is model mongering a part of this decision?

PMH

[ColdFront77]

You're welcome Patricia. It may be that there is now more technology, which apparently is part of the equation. As we move into the future attempting to and improving weather forecasting including tropical meteorology forecasting may make five day forecasts more useful than "just three day forecasts."

[Kevin_Wx]

Any idea what prompted the change?

Many officials (Navy and city) believed that a 5-day forecast used for guidance was necessary to increase the amount of time for preparations. At the same time, these 5-day forecasts should be used as *guidance* only and that they have a high error rate.

We are going to see some HUGE cones on projected storm tracks this season.

[Anonymous]

Well, the NHC extending its forecast period 2 extra days has its pros and cons. The positive change in this is that it will give Navy officials more confidence in route planning. Not just the Navy, but all US and Caribbean residents will have more time to evacuate when necessary. In other words, the benefit of this change is simply more time to prepare for an approaching storm.

However, unfortunately, this change may indeed have tragic consequences. Let's say (hypothetically speaking), a category 4 hurricane well out at sea heading for Miami, FL. What does this cause? Well, obviously, a lot of public panic, media hype, and MILLIONS of evacuations. The majority of the public will NOT be aware of the error rate in 5 day predictions; no second thoughts on accuracy. To everyone's surprise, instead of hitting Miami, the hurricane makes a sharp turn before even getting close. Almost everyone in S FL just evacuated for nothing. SO, the next time a hurricane threatens their area, what will they do? Nothing! Less evacuations = more fatalies.

Another bad-case scenario would be if the NHC doesn't see a strong hurricane hit a certain landmass in 5 days. 5 days later; a hurricane hits. The public had listened to the NHC 5 days earlier in calling for the hurricane to miss, thus, they did not see the need to evacuate. Again, this would translate to more fatalies.

When all is weighted, I do not support the NHC making 5 day forecasts. I mean, they still sometimes bust badly on 3-day forecasts. Add 2 more days and busts become the norm. The smartest thing would have been to wait until they nail 3 day forecasts to perfection, or only have the 4 and 5 day forecasts available to the Navy. I just don't think the public OR the NHC are ready for such long-range forecasts.

[cycloneye]

I dont have to say anymore of what Kevin and Supercane as they are correct on what they said but what I can say is that wishcasting will be prime this season because of that.

[Steve H.]

Or in a worse case, the 5 day forecast shows it going out to sea, everyone ignoring it, then it hitting the coast as a cat 5. Or hitting the coast on the day 5 forecast, going out to sea on the 3 day forecast, then turn and hit the coast on the 2-day forecast. Lots of flexibility and very murky. Clear as mud but covers the ground.

[vbhoutex]

IMO, there is some validity to some of what the "naysayers" are stating here and at the same time I feel that some of the scenarios put forth are somewhat farfetched.

Indeed the "cone of probabillity will widen with each day that a storm is away from land, as it always has. Now, at 5 days out it will be even bigger. Yes it could frighten some unknowledgeable(never been around this type of storm or storm prediction before)or unaware(just don't pay attention to anything going on)people, but to the point of panic ,I doubt it, unless they just do not have a brain in their head and do not listen to what is being broadcast concerning the possibilities. Remember it is the NHC that determines what is going to be given out to the public. Your scenarios assuming mass evacuations 4 or 5 days before a possible landfall seem to me to leave out the IMPORTANT factor that all coastal areas have OEM teams that make the decisions concerning evacuations being needed, not the general public or uneducated broadcasters. In fact, I have seen OEM's make an "informed" decision based on NHC information and order an evacuation 3 days early and the storm went elsewhere. A lot of people were upset and vowed to not evacuate next time. My only response to that is if one is so stubborn and stupid as to not realize that mistakes can be made and they want to endanger their lives by ignoring official directives to evacuate I would hand them a sheet asking for contact information of next of kin and have them sign a waiver of responsibility stating they had been warned. Obviously, there will be those that think they know better than the authorities that will make there own decisions, but not millions. Another consideration I see here is the fact that some areas of all three coasts need at least a 3 day lead time to conduct an orderly evacuation. This has been proven over and over due to lack of adequate evacuation routes almost everywhere.

The scenario where NHC doesn't call for a storm to hit and 5 days later one hits is so far fetched, IMO, that I really can't believe anyone posted it. Come on, an active TC has complete information on its' location, direction, strength, etc. given out at a minimum, every 8 hours and at 4 hour intervals or less when within 36 hours of possible landfall. I may be incorrect on the timeframes, but I do know there is a point where this does happen. I fail to see how a Hurricane could sneak up on anyone except those who would not know about it anyway because they have absolutely no knowledge of storms and absolutely no communication with the "normal" world.

The key word in all of this is the one Kevin pointed out-GUIDANCE-which means to use the information along with other available information to plan and make decisions, not as an absolute "only use this for decisions".
I'm sorry, but in this age of technology that we live in I just can't support the "disaster" scenarios put forward.

Unfortunately, as already pointed out, the 3 day forecasts are not even "that accurate". In fact they are sometimes a major bust, but what is accurate when you are dealing with a storm system that can be anywhere from 100-500 miles across? TC's are not the eye, but an entire very large system that can affect a very large area in some very devastating ways, even when not near the center of the storm.

Is the 5 day forecast good or bad? Will it enhance the military's route planning and protection decisions for it's billions of dollars of equipment? Will it befuddle the public? That remains to be seen.

Personally, I don't think the decision was made to go to 5 day forecasts without every possible thought being given to different scenarios that could arise due to it's implementation.

[ColdFront77]

The National Hurricane Center issues advisories every 6 hours at 5:00 AM, 11:00 AM, 5:00 PM and 11:00 PM in the time zone the tropical cyclone is located in. When they are close to land (not sure exactly how many miles, perhaps about 400 miles) they issue intermediate advisories, which do not include updated model information and some other items that are updated in the above four times a day.

When an intense system is even closer to the coast, two intermediate advisories are issued, thus updates come out every two hours, twelve per day. Again, only updated forecast tracks are updated at 5:00 AM, 11:00 AM, 5:00 PM and 11:00 PM.

[wx247]

So, in essence, the reasoning behind extending it to 5 days was much like the NWS extending the 5-Day local forecast to 7?

[photopete]

Perhaps the folks at the NHC have a new and improved model that they feel confident in. If not then the cone in some cases might reach 180 degrees at its base at the five day point. In any case, using current technology, a five day forcast will tend to make the residents of costal areas pay more attention as the potential landfall area will be huge.

[ColdFront77]

I think so, too, Garrett. Good points, Pete.

Great issues for discussion.

[jabber]

Do not think they are changing the warning issue times... so I do not think folks will panic....

[Stormsfury]

I believe that the hurricane watches and warning criteria are indeed staying the same ... a lot of the less-than-versed on tropical weather people pay attention to those more than the 3 day and 5 day forecasts anyway (thank goodness)...

Great points made here by everyone...and excellent discussions everyone.

[Derek Ortt]

I've said it before and I'll say it again, the exact forecast points are not intended for the general public and IMO should NOT even be made available to them. The discussions and forecast advisories are intended for colleagues in the field and for emergency officials only. The public advisories are what are intended for the public and are the only product that the general public should focus on and for the most part do, and these are not changing at all, so there will not be any excessive hype or cry wolf scenario

[Kevin_Wx]

The public advisories are what are intended for the public and are the only product that the general public should focus on and for the most part do, and these are not changing at all, so there will not be any excessive hype or cry wolf scenario

That's an assumption to me....I think we are forgetting about the hype that the news media brings about when the probability cone is placed close to a certain location. Let's take a little example here: Suppose 5-day forecasts were out when Debby (2000). Around the 19th, I believe, much of the hype about Debby making landfall as a category 4 hurricane in South Florida cranked up. My questions is this: What would a 5-day forecast on the 17th conveyed to Floridians? What would the media do if it the cone of probability was pointing in S. Fla's general direction? If any decent CV storms threaten the US this year, I'll be very interested to see how the media conveys a hurricane hitting a certain location at 5 days.

Other points:
1. The NHC should regulate how the media conveys information. Unless a storm is threatening an area enough to raise a hurricane watch, no claims of a landfall should be made. Instead, warnings should be conveyed in an informational, non-sensational way.
2. People should ignore the media when a storm seems destined towards their location during days 4-5 period of a forecast. Instead, I'd acutally recommend that people listen to a NOAA weather radio or get advisories VIA computer. The media should only be used if a storm is very close or if interests in a certain area have no other means of information.
3. Making 5-day forecasts available this soon may prove to be a mistake simply because of misinterpretation by users.

Finally, Derek, I was wondering by what you meant when you said that the public only uses Public Advisories. Well, the general public also sees forecasted tracks, which is actually a seperate product from the public advisory. The public advisory gives little more than current information on the intensity and current heading of a storm. Just wanted to clarify there.

[ColdFront77]

I agree Mike and Derek.

I don't see why watches and warnings would change with the new forecast format.

For those not interested in tropical meteorology during the off-season and pre-season (April and May), are more likely not going to understand what the "five day forecast cones" really mean. I also hope the media doesn't overhype these situations, the local meteorologists in hurricane prone areas tend to be more conservative (or should be more conservative).