Seasonal Forecasts

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CyclonicFury
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Re: Seasonal Forecasts

#21 Postby CyclonicFury » Wed Aug 12, 2020 4:01 pm

al78 wrote:
CyclonicFury wrote:2. 2006 did not have a top-5 warmest Atlantic MDR on record.


I don't think we do this year either. MDR mean July SST was near average. It has warmed through July up to now and the anomaly is around +0.4. I'd be surprised if that was in the top five. It might be if it were an August-September mean, but not for a current value.

Depends on the dataset. The NCEP/NCAR showed near average MDR SST for July, but the other datasets (OISST, Reynolds, Coral Reef Watch) were well above average. There was an interesting thread about this on Twitter.
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Re: Seasonal Forecasts

#22 Postby al78 » Wed Aug 12, 2020 4:07 pm

CyclonicFury wrote:It's important to remember approximately 85% of all Atlantic major hurricanes form after August 20. We have a long way to go. Sure the season could underperform the very bullish forecasts, but there are not many similarities between 2006 and 2020 other than the very bullish seasonal forecasts.


Yes, I recall August 1998 was quiet up until the end of the third week, then it took off and it stayed active all through September, culminating in the incredibly destructive category 5. hurricane Mitch That was the year of hurricane Georges which seemed to deliberately aim for as much land as possible. The seasonal ACE that year was around 180 which is close or a bit under what the seasonal forecasts are predicting for this year. One difference between now and 1998 is 1998 was a strong La Nina year, whereas this year looks to be more a weak La Nina, so not quite as favourable.
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Re: Seasonal Forecasts

#23 Postby al78 » Wed Aug 12, 2020 4:14 pm

CyclonicFury wrote:
al78 wrote:
CyclonicFury wrote:2. 2006 did not have a top-5 warmest Atlantic MDR on record.


I don't think we do this year either. MDR mean July SST was near average. It has warmed through July up to now and the anomaly is around +0.4. I'd be surprised if that was in the top five. It might be if it were an August-September mean, but not for a current value.

Depends on the dataset. The NCEP/NCAR showed near average MDR SST for July, but the other datasets (OISST, Reynolds, Coral Reef Watch) were well above average. There was an interesting thread about this on Twitter.


The NCEP/NCAR data is the re-analysis I use to generate seasonal forecasts.

Interesting that you say other re-analysis datasets give well above average SST for July MDR. Normally they are not that far out from each other. I may at some point look at what our seasonal forecast would be if we used different re-analysis datasets. If the seasonal outlook is strongly dependant on the re-analysis data used, that needs to be addressed. I have to say I am not familiar with those others you posted, I am only familiar with NCEP/NCAR, ERA5, ERA Interim, 20th Century, MERRA2, HADISST and JMA55.
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Re: Seasonal Forecasts

#24 Postby gatorcane » Wed Aug 12, 2020 4:19 pm

I agree ACE makes more sense. Some of the storms we have seen this year probably wouldn’t have even been caught decades ago yet we say how active this year has been because of the number of storms. Also I am skeptical of seasonal forecasts seeing how models can’t always accurately forecast steering and intensity just days in advance. What do these seasonal forecasts do anyway? I understand the scientific need for better forecasting but if the goal is to keep the public informed, does it matter if the forecast is for an extremely active or less active season? If we don’t know where these storms will go who cares? The preparations for any hurricane season should be the same right? We can already see what it is doing to some of us on this board right now when there is weak activity and we are heading into mid August. I think some had some expectations of a 1933, 2004, or 2005 repeat by now and it is not happening like those years to date :D
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Re: Seasonal Forecasts

#25 Postby toad strangler » Wed Aug 12, 2020 5:55 pm

gatorcane wrote:I agree ACE makes more sense. Some of the storms we have seen this year probably wouldn’t have even been caught decades ago yet we say how active this year has been because of the number of storms. Also I am skeptical of seasonal forecasts seeing how models can’t always accurately forecast steering and intensity just days in advance. What do these seasonal forecasts do anyway? I understand the scientific need for better forecasting but if the goal is to keep the public informed, does it matter if the forecast is for an extremely active or less active season? If we don’t know where these storms will go who cares? The preparations for any hurricane season should be the same right? We can already see what it is doing to some of us on this board right now when there is weak activity and we are heading into mid August. I think some had some expectations of a 1933, 2004, or 2005 repeat by now and it is not happening like those years to date :D


You could very well turn out correct in your skepticism of the many lofty seasonal forecasts out there now but you haven't allowed for the down time that has been well forecasted to run it's course. This consists of at least 10 more days to 2 weeks. In the end I hope your skepticism wins the day, as always, it's a safe bet :D
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Re: Seasonal Forecasts

#26 Postby al78 » Thu Aug 13, 2020 5:07 am

gatorcane wrote:I agree ACE makes more sense. Some of the storms we have seen this year probably wouldn’t have even been caught decades ago yet we say how active this year has been because of the number of storms. Also I am skeptical of seasonal forecasts seeing how models can’t always accurately forecast steering and intensity just days in advance. What do these seasonal forecasts do anyway? I understand the scientific need for better forecasting but if the goal is to keep the public informed, does it matter if the forecast is for an extremely active or less active season? If we don’t know where these storms will go who cares? The preparations for any hurricane season should be the same right? We can already see what it is doing to some of us on this board right now when there is weak activity and we are heading into mid August. I think some had some expectations of a 1933, 2004, or 2005 repeat by now and it is not happening like those years to date :D


Seasonal forecasts aim to predicts the overall seasonal activity using predictors which are known to have a moderate to strong correlation based on historical data. These forecasts do have skill over a zero-intelligence climatology forecast. There is a correlation between total activity and landfalling activity, so advance notice of a very active season will suggest an increased probability of more hurricane damage during the season. This doesn't always hold up in individual years (e.g. 2010), but assessed over the last 60 years, there is a modest link between total and U.S. landfalling activity. It is not unreasonable to think an active season will increase the odds of a damaging landfall. The more storms that spin up, the more chance there is that one of them will form at the time the subtropical high is ridging across to the U.S. east coast. For individual residents, it doesn't really matter, they should be prepared whatever the seasonal forecasts say, and it only takes one for it to be a terrible season for them, but the insurance industry, who deal with managing risk and uncertainty, appreciate a heads up on whether hurricane destruction is likely or not to be higher than average.

It is too early now to say whether the seasonal forecasts are playing out. Almost every hurricane season, even the hyperactive ones have the occasional quiet week. It would be premature to write off the forecasts now just because there hasn't been an explosion in activity yet or because one currently active MDR tropical depression seems to be fighting for its life and isn't expected to intensify beyond a moderate tropical storm. The time to judge the seasonal forecasts is when the season is over.
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Re: Seasonal Forecasts

#27 Postby tolakram » Thu Aug 13, 2020 7:56 am

Frank2 wrote:With all due respect you were only 6 or 7 in 2006, so you might not recall after the disasterous 2005 season forecasters expected the same would carry over into the '06 season, but were surprised when stronger than forecast shear developed in mid-summer (members of this very board insisted it would decrease) and remained that way through August and September.

This year factors are different, they're different every year, but cyclones rely on every factor being enough to support a major hurricane. It's not something that just happens because any combination appear to favor the formation of a hurricane.

For example, the new long-range GFS shows the Bermuda high anchored over the Azores, which favors recurving systems if that turns out to be true.

Every season is different.

Frank


Makes sense Frank, so if an el nino starts to develop we can look at this year and say, aha, same as 2006, maybe time to back off the numbers. That's not happening though, so if you are going to bring up 2006 why not also bring up 2005, which was forecast way below what actually happened? The correction we are seeing this year is by forecasters who are trying to apply lessons learned all the way back to 2005 when making a seasonal forecast.

I strongly reject the notion that forecasts should not be made because the public can't handle them. We went through the dark ages once, we don't need to do it again. Information is not the enemy, technology is not the enemy.
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Re: Seasonal Forecasts

#28 Postby Frank2 » Thu Aug 13, 2020 8:58 am

I agree that hiding truth is not right, but even today if you want to hear a snicker from an operational meteorologist, talk to them about the 360-384 Hour GFS. They still consider it fiction based on climatology, so why make forecasts based on what might happen 3 or 4 months in advance? What is the right or wrong percentage of a 10-day or even a 5-day forecast?

It'd be interesting to know the accuracy percentage of all CSU seasonal forecasts since Dr. Gray began issuing them in the mid-1980's.

In weather forecasting a person can only be 50% wrong, but the public is so overwhelmed at this point, why torment them with breaking news of a disasterous season when they have so much to deal with already? This is what the forecasters I worked for feared - needless worry.

In tough moments I often refer to the Apollo 13 incident, when a controller told Gene Kranz that the spacecraft was shallowing, and his question, "Can they do anything about it?" and hearing they could not, his response, "Then they don't need to know." and the same is true of a disasterous seasonal prediction - not forecast, but prediction.

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Re: Seasonal Forecasts

#29 Postby Steve » Thu Aug 13, 2020 10:27 am

gatorcane wrote:I agree ACE makes more sense. Some of the storms we have seen this year probably wouldn’t have even been caught decades ago yet we say how active this year has been because of the number of storms. Also I am skeptical of seasonal forecasts seeing how models can’t always accurately forecast steering and intensity just days in advance. What do these seasonal forecasts do anyway? I understand the scientific need for better forecasting but if the goal is to keep the public informed, does it matter if the forecast is for an extremely active or less active season? If we don’t know where these storms will go who cares? The preparations for any hurricane season should be the same right? We can already see what it is doing to some of us on this board right now when there is weak activity and we are heading into mid August. I think some had some expectations of a 1933, 2004, or 2005 repeat by now and it is not happening like those years to date :D


Science.

Those years aren't the same as each other either. Plus the idea that something might not have been classified before either of us was born is completely irrelevant.

I say put your money where your keyboard is. If you want to bet the under on a baseline - say 18 named storms/8 or 9 Hurricanes I'm all in on the over for a $50.00 donation to the site. If we end up at the baseline, we can each donate $25.00 and call it even. That way you can cheer for what you post every day and have something riding on it. :sun:

Alternatively, we can bet over/under on ACE = 150. I'd be down for that which I'm less certain of.
Last edited by Steve on Thu Aug 13, 2020 10:30 am, edited 1 time in total.
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Re: Seasonal Forecasts

#30 Postby Steve » Thu Aug 13, 2020 10:29 am

Frank2 wrote:I agree that hiding truth is not right, but even today if you want to hear a snicker from an operational meteorologist, talk to them about the 360-384 Hour GFS


That's cool because everyone here laughs at it too. But the fact that there is any skill at all in that time frame shows progress. Knowledge = power.
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Re: Seasonal Forecasts

#31 Postby toad strangler » Thu Aug 13, 2020 10:59 am

Steve wrote:
Frank2 wrote:I agree that hiding truth is not right, but even today if you want to hear a snicker from an operational meteorologist, talk to them about the 360-384 Hour GFS


That's cool because everyone here laughs at it too. But the fact that there is any skill at all in that time frame shows progress. Knowledge = power.


This. The goal is to have the Mets snickering at the 600 hour GFS one day .. way down the road. It's called #progress
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Re: Seasonal Forecasts

#32 Postby Frank2 » Thu Aug 13, 2020 11:05 am

Josephine was named late this morning and of course the media is into their Noon news "Breaking" mode about a system - that is forecast to weaken and recurve - and this is what I mean about stressing a public already over-stressed about problems that do exist.

It was the purpose of this topic - the meteorology community should have remained silent about questionable long-term hurricane predictions, at least for this season, because of everything else going on in the country and world. No one needs more to worry about at this point, and in fact it was selfish of them to release such a troubling predction during a time of extreme stress.
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Re: Seasonal Forecasts

#33 Postby toad strangler » Thu Aug 13, 2020 11:07 am

Frank2 wrote:Josephine was named late this morning and of course the media is into their Noon news "Breaking" mode about a system - that is forecast to weaken and recurve - and this is what I mean about stressing a public already over-stressed about problems that do exist.

It was the purpose of this topic - the meteorology community should have remained silent about questionable long-term hurricane predictions, at least for this season, because of everything else going on in the country and world. No one needs more to worry about at this point.


It's never a good idea to hold information back. Never ever EVER. That is a slippery slope you should want no part of.
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Re: Seasonal Forecasts

#34 Postby Frank2 » Thu Aug 13, 2020 11:10 am

They should just include it as part of the normal weather segment. It's only done to attract viewers and increase ad revenue. There are times in life that withholding or delaying news is the wise choice - it does happen.
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Re: Seasonal Forecasts

#35 Postby Steve » Thu Aug 13, 2020 11:17 am

Frank2 wrote:They should just include it as part of the normal weather segment.


I agree with you on this. A named storm is certainly "Breaking News" on Storm2k but probably shouldn't be overhyped in Josephine's case particularly when it doesn't really pose a threat to South Florida. I also hate so-called "teasers" where the weatherperson comes on early in a broadcast to tell you to "stay tuned for the weather"
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Re: Seasonal Forecasts

#36 Postby psyclone » Thu Aug 13, 2020 11:19 am

Frank2 wrote:They should just include it as part of the normal weather segment. It's only done to attract viewers and increase ad revenue. There are times in life that withholding or delaying news is the wise choice - it does happen.


It sounds like you're fine with a seasonal forecast as long as it says what you want. Otherwise we must be "protected". No thanks. If you're worried about panic and unwarranted fear..that's valid. choose not to participate in it. I turn off the tv all the time and go fishing or on bike rides. It's fair to say seasonal forecasts are of limited utility right now. Just as the Wright brothers first flight was of limited utility. we're learning. that's good. A dearth of utility today could yield enormous benefit tomorrow. You need to walk before you can crawl. Onward and upward.
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Re: Seasonal Forecasts

#37 Postby Spacecoast » Thu Aug 13, 2020 11:57 am

Frank2 wrote:It'd be interesting to know the accuracy percentage of all CSU seasonal forecasts since Dr. Gray began issuing them in the mid-1980's.
Frank


Yes, it would be interesting. I think I read that NOAA seasonal forecast has a 70% accuracy, with a 70% confidence level, which does not seem to be very high %.
Does this mean it is 70% accurate 70% of the time?

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Re: Seasonal Forecasts

#38 Postby Spacecoast » Thu Aug 13, 2020 12:47 pm

al78 wrote:There is a correlation between total activity and landfalling activity, so advance notice of a very active season will suggest an increased probability of more hurricane damage during the season. This doesn't always hold up in individual years (e.g. 2010), but assessed over the last 60 years, there is a modest link between total and U.S. landfalling activity. It is not unreasonable to think an active season will increase the odds of a damaging landfall.


Landfalling probability is included in CSU Seasonal forecast.

Probability of major hurricanes making landfall:
69 percent for the entire U.S. coastline (average for the last century is 52 percent)
45 percent for the U.S. East Coast including the Florida peninsula (average for the last century is 31 percent)
44 percent for the Gulf Coast from the Florida panhandle westward to Brownsville (average for the last century is 30 percent)
58 percent for the Caribbean (average for the last century is 42 percent)

**The Landfalling Hurricane Probability Project has been co-developed by the Tropical Meteorology Project at Colorado State University and the GeoGraphics Laboratory at Bridgewater State University
This website http://hurricanepredictor.com/ displays landfall probabilities for the United States and Caribbean based on both historical hurricane data as well as the latest forecast from Colorado State University.

I looked up the probability of landfall for my county. Latest Regional Data (Climatology in Parenthesis)

Probability of 1 or more Storms making landfall: 6.9% (3.8%)
Probability of 1 or more Hurricanes making landfall: 3.1% (1.7%)
Probability of 1 or more Intense Hurricanes making landfall: 0.9% (0.5%)
Probability of Tropical Storm force winds in the county: 17.0% (9.6%)
Probability of Hurricane force winds in the county: 4.8% (2.7%)
Probability of Intense Hurricane force winds (>115mph) in the county: 1.8% (1.0%)
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Re: Seasonal Forecasts

#39 Postby al78 » Thu Aug 13, 2020 3:50 pm

Frank2 wrote:Josephine was named late this morning and of course the media is into their Noon news "Breaking" mode about a system - that is forecast to weaken and recurve - and this is what I mean about stressing a public already over-stressed about problems that do exist.

It was the purpose of this topic - the meteorology community should have remained silent about questionable long-term hurricane predictions, at least for this season, because of everything else going on in the country and world. No one needs more to worry about at this point, and in fact it was selfish of them to release such a troubling predction during a time of extreme stress.


Why?

Hiding from the truth or the most likely scenario just because you don't like it doesn't stop it happening, but it does stop you preparing for it, which is highly sub-optimal.
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Re: Seasonal Forecasts

#40 Postby TROPICALCYCLONEALERT » Thu Aug 13, 2020 4:04 pm

Frank2 wrote:Josephine was named late this morning and of course the media is into their Noon news "Breaking" mode about a system - that is forecast to weaken and recurve - and this is what I mean about stressing a public already over-stressed about problems that do exist.

It was the purpose of this topic - the meteorology community should have remained silent about questionable long-term hurricane predictions, at least for this season, because of everything else going on in the country and world. No one needs more to worry about at this point, and in fact it was selfish of them to release such a troubling predction during a time of extreme stress.


To paraphrase (and make it more obvious how ridiculous this sounds), we should ignore a hurricane because the area it's impacting is dealing with a volcano. No need to frighten them before their impending doom, right?
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