Hurricane Forecast Intensity

[Randall Marable]

Hurricane Paloma is the lastest storm where the computer models appear to not have foreseen this type of rapid intensification (Or maybe I should say they didn't expect this degree of intensification). Except in cases where steering currents may temporarily breakdown, forecast track doesn't appear to be much of an issue. However, forecast intensity appears to be a totally different ballgame. Would anyone like to explain why all of our computer model forecasts have had a tendency to underestimate the strength of some of these hurricanes within the last few years? Lack of data and/or timely data? Lack of quality data? Lack of tropical climate knowledge? Unfortunately, in my opinion, it may be just a matter of time someone gets seriously burned by these types of 'unexpected' rapid intensifications by a landfalling hurricane.

 

[rdale]

Remember that reported NHC extreme intensities are very rarely actually verified at landfall (or even by other branches of NHC) so that changes the equation just a bit. In any case, I can't imagine it's so bad that people will get burned at the last second.

 

[Randall Marable]

I guess I should rephrase landfalling hurricane to forthcoming landfalling hurricane. A 1995 Hurricane Opal scenario comes to mind where a storm strengthens unexpectedly as it approaches the coast. In that particular scenario, fortunately the storm weakened right before landfall. I guess my concern is that the populace forecasted to be affected by a particular storm makes preparations for a Catergory 1 or 2 landfalling storm within 24 hours only to be shocked to find out their storm has intensified explosively into a CAT 4 or CAT 5 right before landfall. We all understand a hurricane is hurricane and everyone should be prepared regardless. However, the preparations an area makes for a CAT 1 storm is quite different from the preparations from a CAT 4 or CAT 5. I understand the chances of a scenario such as this are not great, but at that same time still exists to a degree. Again I think the issue is how can we get a better handle on predicting these type of rapid intensification processes. Regardless of whether or not my concerns are legtimate, I'm still curious on what we can do to improve with respect to this particular area of hurricane forecasting.

 

[IAN GIAMMANCO]

I think the key is understanding the inner-core dynamics of a hurricane, what processes control eyewall replacement cycles and their frequency. Also why do systems develop their inner core more quickly than others... throw in air-sea interaction and you have a very very complex problem. Basically modelers need observations to validate the simulations, but we can gain insight in the actual mechanisms at work through varying individual model parameters and evaluating the outcome to see if it matches what we see in the observatons. Right now the state of modeling is getting better and i think the GFDL and HWRF did a reasonable job this season with intensity. I think there is a tremendous need for more observations from the NOAA Aircraft, plus UAV's offer another tremendous data source. Also GPS dropsondes have provided a good chunk of new data now thats only starting to be analyzed.

 

[Randall Marable]

Thanks Ian for the insight, though I would have liked to get more opinions and feedback from other members regarding this issue. Anyhow, I think a big factor regarding the NOAA issue probably boils down to budgets and the willingness of the agency to spend money and time on such ventures. Personally I think it would be well worth the costs in the long run for everyone concerned, but obviously those in charge may feel otherwise for various reasons.

 

[MClarkson]

The problem comes down to scales of motion. While it can be improved, intensity forecasts will never match track forecasts. The inner core covection adds a mesoscale twist to the intensity forecast. The track is mostly synoptic scale, much higher confidence.

 

[Randall Marable]

I guess I could have went into much greater detailed with respect to my 'burned' statement after Hurricane Paloma in Nov. 2008. I didn't want to drag out a long post with issues most people here who visit these types of forums are already familiar with. I'll try to explain the situation with much more detail this time (Ok maybe too much detail). Here's a few things I've personally noticed over the years with respect to hurricane preparation...

When it comes to hurricane preparation, most of the population living in a region susceptible to the impacts of a landfalling hurricane take a passive approach. For one, most people don't make any of the necessary preparations before hurricane season begins. Nine times out of ten (just a guesstimate), most people will wait until the local TV stations begin giving an approaching storm extensive coverage before they rush out and begin making any type of preparations. In addition, most people will sit back and wait on what the local authorities are saying about the hurricane on the local news channels in order to decide what type of actions they will take regarding the approaching storm. Meaning these people will make no attempt to find out what the NHC is saying about the storm. They will not find out what the NHC and local NWS advisories, watches, and warnings will mean to them and what impacts those warnings will have for their area. They will not try to get familar with some of the products offered by the NHC, the NWS, NOAA, and/or any other helpful online weather websites. Nor will they even take the time to learn anything about the simple basics of a hurricane period. In other words, most people depend upon what the local televison stations are saying or what their friends and family are saying about the storm. This is pretty much it when it comes to their storm preparation. Bottomline, most people limit their source for information regarding an approaching hurricane exclusively to the local news media, without putting forth an effort to educate themselves accordingly. (Let me emphasize there is absolutely nothing wrong with tuning in to local media coverage of an approaching storm. And I would highly recommend it.) The ironic part about some of these people is that even when they are warned accordingly, they still don't take the appropriate actions necessary, but that's a whole totally different topic.

Now can one get away with this type of approach to hurricane preparation? I guess technically they can. Am I over-generalizing people in hurricane impact zones? May-be. The only problem with this passive approach is that sometimes local news media, local authorities, friends and family may not necessarily fully understand the importance of some of the things I just listed above. So though "the state of the science and forecast ability (or lack of) is quite well known", question is, has the local media conveyed this idea to their 'passive preparing public locals' with respect to an approaching hurricane and do some of these local officials even fully understand this concept themselves? Personally, Rich Horodner I agree with this statement regarding forecast ability. However, the only issue I have is since most people don't take the time to educate themselves regarding hurricane preparations and hurricane topics and resources in general, they will depend exclusively upon local media to obtain information regarding an approaching storm. Now if the local media and local officials haven't conveyed the fact that those hurricane forecasts of that approaching storm are not an exact science, then these exact same people will most likely not take into account any other possibilities. Thus might explain why some people get 'pissed' in the Florida Keys when a hurricane misses them. And it's just not the Keys, this happens everywhere. Which may explain why Mayor Nagin hesitated to order the mandatory evac before the approaching Katrina.

So in essence, what I eventually see happening one day is that a hurricane will be forecasted to strike a certain area with a forecasted intensity (with the usual disclaimers and margins for error issued by the NHC). The local media and authorities will respond accordingly. Then we have all of our people who use the 'passive' approach to hurricane preparation following suit and making plans accordingly. Unfortunately, this particular hurricane significantly intensifies unexpectedly before making landfall. All of our passive preparing population is totally taken offguard and now wants to know what went wrong with that intensity forecast.

In retrospect, I kinda saw this happen in South Florida with Hurricane Andrew, though this situation is not the best example of what I eventually see happening one day. After reading over most of the newspaper articles leading up to 1992's Hurricane Andrew, most of the population affected, which seemed to take the ill-advised, but most popular 'passive hurricane preparation approach', appeared to be caught off guard by a Category 5 landfalling hurricane. Andrew made landfall on a Monday morning. Most of the people appeared to make most if all not all of their preparations on that Saturday afternoon thru Sunday before the storm struck. It also appeared that most people began making their first hurricane preparations of the 1992 hurricane season that Saturday morning and afternoon, only after local news television stations began reporting just how much Andrew was intensifying. Many of the people who felt the full impacts of Andrew appeared to be taken totally offguard by the sheer ferocity of the storm. (On second thought, maybe this is just a bad example totally, because after reading through all of those pre-Andrew articles, even the NHC and everyone else appeared to be somewhat taken offguard by the intensity and widespread devastation of Hurricane Andrew.)

Let me make it clear I don't disagree with anything anyone has said thus far. I guess one of the main issues I see involving 'someone getting burned' is derived from a possible combination of an unexpected intensification by an approaching hurricane coupled with the 'passive hurricane preparation approach'. Many may argue that people don't have to be weather ethusiasts and geeks to prepare for a hurricane. I would agree this is true. And I guess one can successfully argue that this so-called 'passive approach' I've described above most times is sufficient in hurricane preparation. I will concede this point as well. One may also argue 'who has the time to be learning about hurricanes, NHC and NWS products, etc. I would answer anyone who lives in a region prone to the impacts of hurricanes. In addition, one may argue that the chances of a hurricane rapidly intensifying right before landfall is fairly low and not a real issue or threat. This also may be true as well to a certain degree.

I guess the real challenge is hurricane education. Everyone concerned needs to take the necessary time in order to find out what types of things they need to know when it comes to hurricane preparation and hurricanes in general. Thus, if we do eventually have a situation as I descibed above involving an intensifying hurricane, we may be able to avoid the 'burn factor'. From what I've observed over the years, this appears to be a very tall order.

 

[Randall Marable]

The reason the NHC did this in the 1970's and 1980's is because Dr. Neil Frank was a strong advocate of uniformity when it came to the dissemination of hurricane information, data, and forecasts to the general public. He didn't want the NHC to forecast one thing, the Weather Channel forecasting something different, and Accuweather forecasting something totally on the contrary. (I know they weren't around during some of his tenure and I'm just using these entities as examples to illustrate a point and not as a personal attack on anyone.) He felt this would cause a great deal of confusion within the possible affected areas and possibly compromise the goals and missions of the NHC. He would always emphasize how important it was that everyone was on the 'same page' when it came to this dissemination of the NHC info and hurricane preparation. So in essence maybe his actions probably tells us he didn't trust very many local, state, and national entities with interpreting NHC information and relaying it to the public. This makes sense. The NHC are the trained and experienced experts.

Since Dr. Neil Frank's tenure, today we have quite a few 'experts' that know how to interpret and disseminate this data. Some of who may or may not have the general public's best interests in mind.

As far as Hurricane Andrew, I think the NHC made some changes on how they estimate hurricane surface winds with respect to the flight level winds recorded by the recon flights. I think this is one of the reasons the NHC upgraded Hurricane Andrew to a Category 5 storm ten years later. For those of you who haven't read this yet, here is a very good Disaster Survey Report concerning Hurricane Andrew...http://www.nws.noaa.gov/om/assessments/pdfs/andrew.pdf. Here is a very small excerpt from this report...

"The DST found that NOAA performed exceptionally well both prior to and during Hurricane
Andrew. The hurricane forecast track error was 30 percent less than average. Lead times on
hurricane watches and warnings were 3 to 6 hours better than average. Hurricane watches
were issued with 36 hours of lead time in south Florida and 43 hours in Louisiana. Hurricane
warnings were issued with 21 hours lead time in south Florida and 36 hours in Louisiana.
Throughout the event, NWS personnel, despite enormous personal hardship, supplied timely,
high quality information to the public via NOAA Weather Radio (NWR), NOAA Weather Wire
Service (NWWS), direct links with emergency management, and the mass media. To assure this
flow of vital information, contingency plans were activated for backup of the NHC and for the
Weather Service Forecast Office (WSFO) at Miami should they have become unable to function.
Those plans were not needed for the NHC, but WSFO Atlanta and Weather Service Offices
(WSO) at Tampa Bay and West Palm Beach provided forecasting issuance and backup warnings,
respectively, for WSFO Miami.

State, county/parish, and local emergency management agencies, working in concert with law
enforcement and based on information supplied by the NWS, coordinated some of the largest
evacuations in United States history. In south Florida, as well as Louisiana, literally hundreds
of thousands of people left their homes.

The DST found that the collection and dissemination of information, through appropriate
warnings and statements, need improvement. In particular, hurricane local statements (HLS)
need to be shortened and reorganized to provide more timely and specific information pertaining
to the local area. The DST found also that WSOs and WSFOs need to address storm-scale
events occurring within hurricanes by using appropriate severe weather warnings and
statements, including tornado warnings. Additionally, Andrew re-emphasized the need for
improvement in hurricane intensity forecasting. Finally, the DST found that wind, not storm
surge, was the major cause of direct deaths in Andrew. Still, these statistics need to be kept in
perspective: 12 of the 15 deaths directly attributed to Andrew in Florida were caused by wind
as compared to the potential for hundreds of fatalities that could have occurred from storm
surge. The reality is that evacuation from wind would involve far too many people to be
accomplished; alternative shelter may be necessary."