ATL: IRMA - Models

[SouthDadeFish]

Really starting to get annoyed by all these spaghetti plots of deterministic models, half of which are trash. I know many on this board understand what they mean and that they can change, but from social media, I get the feeling a good chunk of the public is being deceived.

Use the ensembles to your advantage. Even in the notoriously under-dispersive GEFS, there are still multiple members that hit FL, including the west side of FL. The EC ensembles are actually centered on FL. The ensembles are designed to represent the amount of uncertainty in a given forecast. With the large spread in the members, it is clear there is a lot we are still unsure about in the track forecast of Hurricane Irma. Anyone within this spread should not let their guard down. There is a reason the NHC's cone is as wide as it is. This is a tricky forecast. Prepare for the worst and hope for the best.

Sorry for the rant.

[Voltron]

So Local 10 showed fellow viewers this spaghetto plot.


upload an image

Not sure why but they really hammered it hard.

That's very irresponsible of them IMO...I can't believe they are showing that on TV

Why is that irresponsible? Models are models, they need to understand all of the information and be informed to make a decision, this is massive people movement we are talking about. If the models continue to trend east and up the coast to the carolinas as projected then that is great news for FL.

[LoveWeather12]

So Local 10 showed fellow viewers this spaghetto plot.


upload an image

Not sure why but they really hammered it hard.

That's very irresponsible of them IMO...I can't believe they are showing that on TV

Why is that irresponsible? Models are models, they need to understand all of the information and be informed to make a decision, this is massive people movement we are talking about. If the models continue to trend east and up the coast to the carolinas as projected then that is great news for FL.

We can't let our guard down tho. It's very bad to say we are out the woods. You are playing with people's lives. I don't call a cat 5 20 miles off the coast a good trend

[AdamFirst]

Really starting to get annoyed by all these spaghetti plots of deterministic models, half of which are trash. I know many on this board understand what they mean and that they can change, but from social media, I get the feeling a good chunk of the public is being deceived.

Use the ensembles to your advantage. Even in the notoriously under-dispersive GEFS, there are still multiple members that hit FL, including the west side of FL. The EC ensembles are actually centered on FL. The ensembles are designed to represent the amount of uncertainty in a given forecast. With the large spread in the members, it is clear there is a lot we are still unsure about in the track forecast of Hurricane Irma. Anyone within this spread should not let their guard down. There is a reason the NHC's cone is as wide as it is. This is a tricky forecast. Prepare for the worst and hope for the best.

Sorry for the rant.

A needed rant. People also look at the line and think that just because it's offshore to the east it won't be an impact event for South Florida.

[Category6]

Really starting to get annoyed by all these spaghetti plots of deterministic models, half of which are trash. I know many on this board understand what they mean and that they can change, but from social media, I get the feeling a good chunk of the public is being deceived.

Use the ensembles to your advantage. Even in the notoriously under-dispersive GEFS, there are still multiple members that hit FL, including the west side of FL. The EC ensembles are actually centered on FL. The ensembles are designed to represent the amount of uncertainty in a given forecast. With the large spread in the members, it is clear there is a lot we are still unsure about in the track forecast of Hurricane Irma. Anyone within this spread should not let their guard down. There is a reason the NHC's cone is as wide as it is. This is a tricky forecast. Prepare for the worst and hope for the best.

Sorry for the rant.

Amateur here, don't know much about models. Can you explain the difference between the singular model tracks posted on here and the ones you see on the news vs. the ensembles? Thanks!

[LoveWeather12]

Looking better for Florida. Unfortunately, with that comes an increase in danger for the Carolina's. Yesterday although Florida was going to get nailed it was better for us because it would have taken most of the energy out of Irma. In fact in yesterday’s run the Outer Banks would have been one of the least affected because it is so far east. I guess we're not out of it yet. Best hope is still out to sea.

Based on what you're saying , I guess I should take my hurricane supplies back. Since I live on the east coast of Florida

[Ken711]

So Local 10 showed fellow viewers this spaghetto plot.


upload an image

Not sure why but they really hammered it hard.

That's very irresponsible of them IMO...I can't believe they are showing that on TV

Why is that irresponsible? Models are models, they need to understand all of the information and be informed to make a decision, this is massive people movement we are talking about. If the models continue to trend east and up the coast to the carolinas as projected then that is great news for FL.

First off, it's lacking the Euro. Second, as others have said post the NHC cone that's what is matter for preparedness purposes.

[SouthFloridian92]

I wish it was Friday already so we could know what's going to happen!!

[NJWxHurricane]

Looking better for Florida. Unfortunately, with that comes an increase in danger for the Carolina's. Yesterday although Florida was going to get nailed it was better for us because it would have taken most of the energy out of Irma. In fact in yesterday’s run the Outer Banks would have been one of the least affected because it is so far east. I guess we're not out of it yet. Best hope is still out to sea.

Based on what you're saying , I guess I should take my hurricane supplies back. Since I live on the east coast of Florida

Please stop exaggerating his translation that's not what he meant.

[Voltron]

Why is that irresponsible? Models are models, they need to understand all of the information and be informed to make a decision, this is massive people movement we are talking about. If the models continue to trend east and up the coast to the carolinas as projected then that is great news for FL.

First off, it's lacking the Euro. Second, as others have said post the NHC cone that's what is matter for preparedness purposes.

100% agree.

Now that I can get on board with!!!! Everyone needs to just stay on top of the models. I worry for the Carolinas with the trend, but if you review it has a sharp turn We once in the Carolinas, I find that rather hard to believe but rather more of a middle solution at the end of the day.

[SunnyThoughts]

Can't determine where this storm may go by watching one day's worth of model runs. Rick Scott just finished a press briefing. He said the entire state still needs to watch, from the east coast, to the west coast, and even the panhandle. Nobody is out of the woods yet.

[Emmett_Brown]

Not sure if anyone has already mentioned it, but Irma's current position is almost 1 degree S/SW of where the 6z GFS forecasted for 18z. So, it got the short term motion wrong.

[AutoPenalti]

So Local 10 showed fellow viewers this spaghetto plot.


upload an image

Not sure why but they really hammered it hard.

That's very irresponsible of them IMO...I can't believe they are showing that on TV

Why is that irresponsible? Models are models, they need to understand all of the information and be informed to make a decision, this is massive people movement we are talking about. If the models continue to trend east and up the coast to the carolinas as projected then that is great news for FL.

People are not educated enough about this stuff, they think lines are shifting east means that it's out to sea or that it won't be threatening SFL. I have friends who shared that same exact plot and are all angry at me and telling me that "I'm scarying people for no reason", "I knew this was going out to sea to begin with" "It's not coming", "I bought all this stuff for no reason", little do they know that they can change right back to the spine.

[SouthDadeFish]

Really starting to get annoyed by all these spaghetti plots of deterministic models, half of which are trash. I know many on this board understand what they mean and that they can change, but from social media, I get the feeling a good chunk of the public is being deceived.

Use the ensembles to your advantage. Even in the notoriously under-dispersive GEFS, there are still multiple members that hit FL, including the west side of FL. The EC ensembles are actually centered on FL. The ensembles are designed to represent the amount of uncertainty in a given forecast. With the large spread in the members, it is clear there is a lot we are still unsure about in the track forecast of Hurricane Irma. Anyone within this spread should not let their guard down. There is a reason the NHC's cone is as wide as it is. This is a tricky forecast. Prepare for the worst and hope for the best.

Sorry for the rant.

Amateur here, don't know much about models. Can you explain the difference between the singular model tracks posted on here and the ones you see on the news vs. the ensembles? Thanks!

My attempt at explaining:

Basically, different organizations run a main model (deterministic), if you will, at a relatively high spatial resolution, using the best observations we have. Then we also run ensembles, which are slightly lower resolution versions of the same model (for the most part) that try to account for things we are unsure of. For example, one ensemble member may have a stronger ridge to the N of Irma than the deterministic model to account for potential error in observations or a lack of observations. Another ensemble member may have a stronger trough than the deterministic model. As a result, the outcome of the ensemble simulations will be different. By running many different ensemble simulations, we hope to capture the total range of realistic possible outcomes. We can then use this information to get an idea for what the probability of a certain outcome is. If many ensemble members are predicting a similar outcome, then that forecast is believed to be more likely.

That explanation was crudely summarized and those mets more familiar with modeling can feel free to correct anything I said.

More info here: https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-ensemble-forecast-system-gefs

[jlauderdal]

Why are folks saying that South Florida is looking better? Actually it looked better yesterday with the core passing around Key West. Now the consensus of the GFS and ECMWF has the core just offshore the SE Coast of Florida coming in from the SOUTH raking the entire SE Florida coastline. If that track holds, Matthew's impacts on SE Florida will pale in comparison! Matthew came in from the SE and was far enough away SE Florida to not cause a big issue.

Here is what the best performing model is doing. Things are looking better? I don't think so:

its about the trend, if the trend continues its good but the danger is now we coudl take a direct hit where yesterday it looked as though it had a chance to go into the gulf and that seems to be decreasing...our risk for a direct hit has actually increased today but so has east of us...high stakes for sure

[hurricaneCW]

People also forget that hurricanes are not points, they have far-reaching impacts hundreds of miles from the center.

While not the greatest example, Sandy hit S NJ but had tremendous impacts across LI and the NYC metro. Irene caused massive flooding in New England hundreds of miles away.

To say Florida is in the clear is the most foolish thing you can say at this juncture.

[jlauderdal]

And then Ryan Maue tweets this... :

 https://twitter.com/RyanMaue/status/905419696740151296

well based on the modeling and nhc track we should prepare for a direct hit, chances of a direct hit and chances of east have went up while gulf has went down...at this point we are just slicing up the pie differently in terms of risk

[gatorcane]

IRMA is south of even the 6 hour GFS track already. That should tell you something not to mention the model has been right-biased for most of this storm. Remember when it showed it going north of the Leewards several days ago?

[Emmett_Brown]

Why are folks saying that South Florida is looking better? Actually it looked better yesterday with the core passing around Key West. Now the consensus of the GFS and ECMWF has the core just offshore the SE Coast of Florida coming in from the SOUTH raking the entire SE Florida coastline. If that track holds, Matthew's impacts on SE Florida will pale in comparison! Matthew came in from the SE and was far enough away SE Florida to not cause a big issue.

Here is what the best performing model is doing. Things are looking better? I don't think so:

its about the trend, if the trend continues its good but the danger is now we coudl take a direct hit where yesterday it looked as though it had a chance to go into the gulf and that seems to be decreasing...our risk for a direct hit has actually increased today but so has east of us...high stakes for sure

Good point. Also, on that Euro run, there are 24 hour increments between positions.... so it is possible that a direct SFL landfall occurs but is not visible due to the time increment.

[caneman]

Not sure if anyone has already mentioned it, but Irma's current position is almost 1 degree S/SW of where the 6z GFS forecasted for 18z. So, it got the short term motion wrong.

If that's true, that's not good. A more Southerly and westerly track would likely favor more of a Florida hit. Anyone else agree?