Accuweather & NWS predictions

[iceangel]

predictions of Accuweather and the National Weather Service.

NWS
The N.W.S. is calling for 12-15 tropical cyclones, including 7-9 hurricanes, and 3-5 major hurricanes, which means a category three storm or stronger. The Weather Service says 3 to 5 of those storms would hit the U.S. mainland.

Accuweather
Accuweather believes the season will produce 13 named tropical cyclones, 3 to 5 of which will become landfalling hurricanes, 1 of those becoming a major landfalling hurricane.

[caneflyer]

If you read the text of the NOAA forecast:
http://www.cpc.ncep.noaa.gov/products/o ... icane.html
there really is no NOAA forecast of landfalls. Just ranges for the expected values of named storms, hurricanes, major hurricanes, and the ACE index.

[StormChasr]

Nobody forecasts landfalls, as that is impossible. Each season, landfalls are situational, and specific to the conditions that exist at that time, and cannot by nature, be predicted. Number of storms can be accurately estimated to a degree, but not landfalls.

[iceangel]

If you read the text of the NOAA forecast:
http://www.cpc.ncep.noaa.gov/products/o ... icane.html
there really is no NOAA forecast of landfalls. Just ranges for the expected values of named storms, hurricanes, major hurricanes, and the ACE index.

What is the ACE index?
http://pensacolanewsjournal.com/news/st ... ther.shtml

PUBLISHED MONDAY, MAY 16, 2005

Expect more, bigger hurricanes, experts say
Sean Smith
@PensacolaNewsJournal.com

Another hurricane forecast is in. (NOAA)

It ain't pretty.

The National Oceanographic and Atmospheric Administration today predicted 12 to 15 named storms for the 2005 Atlantic hurricane season, with seven to nine of those becoming hurricanes and three to five of those becoming major storms, at least Category 3 storms with sustained winds greater than 115 mph.

That's worse than last year's prediction and more serious than the April 1 forecast by William Gray of Colorada State University. The 2004 NOAA forecast also predicted 12 to 15 named storms, but six to eight hurricanes and two to four major hurricanes.

"It's almost identical to last year. Overall, we are going into a pattern of increased frequency of hurricanes," said John Purdy, meteorologist with the National Weather Service in Mobile. "People need to be prepared. Last year was about as concerned as you can ever be.

"Take the lessons learned from last year. Be prepared for a similar occurrence.

[caneflyer]

The ACE index is an overall measure of TC activity. It is calculated as the sum of the squares of the wind speeds (in kt) for all tropical storms and hurricanes every 6 hours of their existence. This measure favors long-lasting intense storms, such as Ivan or Isabel.

[kevin]

Nobody forecasts landfalls, as that is impossible. Each season, landfalls are situational, and specific to the conditions that exist at that time, and cannot by nature, be predicted. Number of storms can be accurately estimated to a degree, but not landfalls.

That is mathematically improbable, but it doesn't stop people from trying. I will direct you to the fortune tellers and the fallacy of positive occurance. You're into statistics if I remember correctly so you know more about how gullible people are than I do.

[StormChasr]

That is mathematically improbable, but it doesn't stop people from trying. I will direct you to the fortune tellers and the fallacy of positive occurance. You're into statistics if I remember correctly so you know more about how gullible people are than I do.

Absolutely. I would often point out examples of statistical improbability and fallacy all the time, when I taught the probability course. Just like ppl saying that Florida will be pounded by 4 storms again this year--that falls into the fallacy trap. However, one or two majors making landfall somewhere in the CONUS is quite probable.

[hcane]

Nobody forecasts landfalls, as that is impossible. Each season, landfalls are situational, and specific to the conditions that exist at that time, and cannot by nature, be predicted. Number of storms can be accurately estimated to a degree, but not landfalls.

I beg to differ. Landfalls have been forecasted in advance for the lat 3 years with a very high percentage of accuracy. Granted, while not yet 100%, it appears to be well outside the "lucky guess" window.

http://www.hurricanealley.net/Forecast/ ... 005MAY.htm

check the previous years' verifications.

That you consider the prospect of forecasting landfalls impossible, consider that just a few years ago they thought Dr. Gray's numbers forecasts were impossible. Now, he holds the attention of everyone. Just food for thought.

[cyclonaut]

In the case of Hurricane Alley if you highlight most of the US coast youre bound to score some hits..or at least thats how it appears.

[Steve]

As science has progressed and data collection has improved dramatically (as has our understanding of the weather in general) I think we're pretty much on the cusp of acknowledging that there are indentifiable risks. It's never going to be 100%, but we're moving forward. It wasn't that long ago when quantifying seasons was nearly outside of science. But Dr. Gray kept on researching, and enthusiasts kept on reading. Now most of us amateurs can put together a decent #'s forecast out there.

While not going on pure analogs, if we find ourselves in certain weather patterns that have evolved in certain ways with certain windflows and ocean temperatures (among many other things) and see what similar situations have yielded in the past, we have an idea of what might happen in the future. There's never going to be a guarantee that all of the ingredients will line up to sniff a storm out of a pattern or that a storm will be influenced the same - chances are there will always be different variables, but the potential for certain events follow various rules of nature. For instance, something I'm looking at on the high res SST of the Gulf, there's a pretty warm tongue inching up from the Caribbean to the mouth of the Mississippi River. I would say watch and see what that does over time. Should that water stay anomalously warm compared to heating in the rest of the Atlantic Basin and Gulf, I'd be paying attention if I were in Mississippi or Alabama. We know that some hurricanes like to stay in the warmest currents as they can help even out the differences. If it starts warm and reverses, then either side of that might have potential for something significant. It's just something to watch for down the line.

https://128.160.23.54/products/OFA/gsscofa.gif

Also, you can look at mean trof and ridging positions from the winter and how they backed up or progressed to get an idea where the summer position might be at so-called "high tide". Does it back to 80 West, 90 West, 100 West? And if so, what might be coming up at a given time?

Ultimately, just like many people successfully forecasted greatest areas of winter impact, I think identifying tropical influence is on the horizon. Someone's going to hit it close over a period of time that we'll have to pay attention. And while no one will ever be 100%, as the science continues to mature, we should start to see the who's who over the next 5-10 years.

Here's another one, and it's not me, many respected forecasters and professional mets like the idea for a late May or early June storm this year. Statistical liklihood is low. But recognition of patterns and where we're going toward a deeper trof position after 10-12 days and out for the 2 weeks after that shows that energy backing into a trof or a split could well spawn something in the NW Caribbean or SE Gulf. It's not a call I'm making, but with nothing evident yet for the 2-4 week period, obviously some see the potential.

So in other words, I wouldn't blow it off completely. I'd just be watching to see who's putting out what and how well they're doing. Indepedent Wx is due out with their seasonal forecast on 5/25. I'm pretty sure they delve into some landfall stuff too. They do a very good job, so that's one of the places I'll be watching (among about 10 others).

Steve

[rainstorm]

accuweather says 3-5 canes will make landfall, but do they say landfall in the us? they could hit canada, bermuda, bahamas, mexico, carib islands

[Derek Ortt]

canot predict landfalls on a year to year absis. You can on a month by month, if we can ever get a model that can represent a monthly mean steering flow and shear

[kevin]

Yes guys, there is no way you can predict landfalls a year in advance or even months in advance. For one thing a small deviation can mean a hundred mile error, for instance the small error with Charley and the resulting confussion.

Regardless of what any group says they can do I won't believe they can do it until the methodology is published, the results show a strong correlation, and it is done by others. That is how experiments work. Now I understand there is the hard science of atmospheric equations and the squishy science of forecasting (especially amateur) but we cannot say things like 'it appears they are able to do it' or 'well hurricanealley was right on last season' because this is part of the fallacy of positive occurance.

Do you remember all the times when seasonal forecasts in terms of TS/HUR/INT were wrong? There is almost 100 forecasts on this board. One of them is bound to be correct. The person who is correct unless it is me will think they are special. Really more than likely they were lucky. Some people put significant work into their forecasts but unless their results are studied and their methodologies published they are in essence doing a lot of busy work to be as good as my guess.