Major Hurricane Irma

[Maxwell03]

I think we have been looking at the Cuba landfall as a saving grace for FL but still a bad scenario if it survives Cuba in decent shape and emerges in the Florida Keys. Better than a head on Cat 5 strike, but still dicey. 

[NJwx85]

One thing that's been consistent on the Euro is that it pretty much dissipates the storm very quickly once North of the Carolinas. You would think the Northeast would be in for a significant rainfall but that doesn't appear to be the case, kind of reminds me of Hugo.

[jbenedet]

On the euro, trough over the east coast was actually deeper on 12z versus 6z.

The differentiating factor here, resulting in the track further west was the development of a TC in the western Gulf on the 12z euro which acted to build back the ridge, causing the recurve to happen later, into western Fla.

Lots of players on the field here...

[pazzo83]

So Havana is at about 23 degrees N latitude, right now Irma is at 16.9 degrees N.  I guess we'll see how far N she gets.

[McQuackleton]

Even with a direct Cuba hit for about a day, why are the max winds still showing 157 right on the Keys in one of the maps posted 10 minutes ago?

[Ginx snewx]

4 minutes ago, skierinvermont said:

30 hrs over Cuba will weaken it a lot even without mountains. Cat1 would be my guess maybe Cat2. But there's a big difference if it's just 10-20 miles farther north which would keep the eye right on the coast I think and not fully on land for most of the period. Could probably maintain Cat3 if the eye is not fully on land for more than 3-6 hours. 

Given how accurate the Euro has been and usually is, we will probably find out.

even though it is best euro also has a 120KM 4 day track error so keep that in mind

[jayson]

Just now, AcePuppy said:

Even with a direct Cuba hit for about a day, why are the max winds still showing 157 right on the Keys in one of the maps posted 10 minutes ago?

Because the models are awful at forecasting intensity. 

[skierinvermont]

It almost has to thread the needle NOT to be a major for FL. That is an exaggeration of course, but if it stays NE it misses Cuba and hits Miami. If it goes too far SW it will likely track up the west coast of FL giving more time for strengthening on 30-31C surface waters and exposing a large area to the right front quadrant. It would have to take a big chunk of Cuba but then turn north soon enough to hit far South FL. 

[pazzo83]

Just now, AcePuppy said:

Even with a direct Cuba hit for about a day, why are the max winds still showing 157 right on the Keys in one of the maps posted 10 minutes ago?

SSTs right around there are approaching 90F - so I would imagine a rapid intensification upon re-entering the water is possible.

[Stormlover74]

Just now, AcePuppy said:

Even with a direct Cuba hit for about a day, why are the max winds still showing 157 right on the Keys in one of the maps posted 10 minutes ago?

Because it has time over open water to re-strengthen. Also those are gusts not sustained

[Ginx snewx]

3 minutes ago, AcePuppy said:

Even with a direct Cuba hit for about a day, why are the max winds still showing 157 right on the Keys in one of the maps posted 10 minutes ago?

931

[Hoosier]

We're not going to be able to resolve this Cuba/no Cuba/how much of Cuba issue for a while, but it should not affect anybody's preparations at this point.  Plan for the potential of a category 4-5 hurricane and keep watching models and forecasts.

[thewxmann]

Just now, jayson said:

Because the models are awful at forecasting intensity. 

Yeah they did this with Ike too, having it deepen by quite a bit over the Gulf despite its inner core getting shredded.

The Keys and the west coast of FL are more surge prone than the east coast of FL however. So in that track, the surge could still create havoc. Pick your poison really.

[Jaguars]

Can anyone provide Euro images after it gets through central Florida?

[NJwx85]

I feel silly even saying this, but looks like Irma is about to take off again. Outflow has increased again, especially to the South of the center. The eye is about as symmetrical and clear as it has been during its existence. And cloud tops have really begun to cool again over the past hour or so.

[Suncat]

Something not being discussed here is the influence the development of a low near Missouri will have on steering Irma north then northwest.  The timing of the northward turn will depend on the timing of the development and strengthening of this low. NWS Raleigh is leaning toward a faster turn to the north with the hurricane tracking along the eastern coast of Florida and then a turn to the northwest between Georgia and South Carolina.  At this point, some of the models may not taking this low into consideration.

[thewxmann]

Just now, Suncat said:

Something not being discussed here is the influence the development of a low near Missouri will have on steering Irma north then northwest.  The timing of the northward turn will depend on the timing of the development and strengthening of this low. NWS Raleigh is leaning toward a faster turn to the north with the hurricane tracking along the eastern coast of Florida and then a turn to the northwest between Georgia and South Carolina.  At this point, some of the models may not taking this low into consideration.

The models are taking it into consideration, and that's why they (almost) unanimously turn Irma northward near Florida.

[wxmx]

10 minutes ago, skierinvermont said:

30 hrs over Cuba will weaken it a lot even without mountains. Cat1 would be my guess maybe Cat2. But there's a big difference if it's just 10-20 miles farther north which would keep the eye right on the coast I think and not fully on land for most of the period. Could probably maintain Cat3 if the eye is not fully on land for more than 3-6 hours. 

Given how accurate the Euro has been and usually is, we will probably find out.

Agree. Look at what happened to Gilbert, Dean or Janet after crossing the flat Yucatan peninsula.

[McQuackleton]

2 minutes ago, Jaguars said:

Can anyone provide Euro images after it gets through central Florida?

 

then heads into Northern NC.

[4waresnowcone]

Just now, Suncat said:

Something not being discussed here is the influence the development of a low near Missouri will have on steering Irma north then northwest.  The timing of the northward turn will depend on the timing of the development and strengthening of this low. NWS Raleigh is leaning toward a faster turn to the north with the hurricane tracking along the eastern coast of Florida and then a turn to the northwest between Georgia and South Carolina.  At this point, some of the models may not taking this low into consideration.

When can we expect a more definitive model?

[Casualbrain]

7 minutes ago, lilj4425 said:

If the GFS verifies you can all forget about it hitting Cuba.

It will be interesting to see what the next initialization incorporating the special midwestern trough radiosonde data does.

[Ginx snewx]

2 minutes ago, Jaguars said:

Can anyone provide Euro images after it gets through central Florida?

Eyes on you?

[WeatherEmperor]

Man, the divergence in the GFS and Euro in terms of Florida is coming at an absolutely horrible time IMO.  Officials should just tell everyone to leave the areas that could be affected, but they won't want to be wrong.  Hopefully the next set of models clarify this divergence.  After watching the Sandy situation closely I am inclined to almost always believe the Euro, as it hit that situation with many days to spare.  But who knows.

[weaponxreject]

First post, thanks for the insight and education. Hoping to make a career out of this!!

Out of curiosity though... As was mentioned a page or two back, the latest Euro initialized with an ~40mb strength higher than where Irma is now. What, if any, impacts would that have on the forecasted track, especially beyond 72hrs?

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[OUGrad05]

2 minutes ago, Casualbrain said:

It will be interesting to see what the next initialization incorporating the special midwestern trough radiosonde data does.

That's for 18Z?  

[Jaguars]

2 minutes ago, AcePuppy said:

 

then heads into Northern NC.

appreciate it

[bdgwx]

It appears to me the main driver in the quicker tug north on the GFS is the upper level trough is a little more potent. They both place Irma favorably in the right entrance region of an anticyclonically curving jet streak, but the GFS does it sooner and with more bravado. If the interaction with the trough doesn't increase wind shear too much then both the GFS and Euro are highly favorable for a strong cyclone at least in terms of the upper air pattern. Land interaction would obviously be a mitigating factor while SSTs are a supporting factor. 

[wxmx]

1 minute ago, weaponxreject said:

First post, thanks for the insight and education. Hoping to make a career out of this!!

Out of curiosity though... As was mentioned a page or two back, the latest Euro initialized with an ~40mb strength higher than where Irma is now. What, if any, impacts would that have on the forecasted track, especially beyond 72hrs?

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Negligible. It's still depicted as a well stacked, deep cyclone, steered by a deep ridge, so that translates to having almost no impact on track.

[weaponxreject]

Negligible. It's still depicted as a well stacked, deep cyclone, steered by a deep ridge, so that translates to having almost no impact on track.

Thank you!! I know not to read too much into the longer range intensity forecasts with some of the models, I just wasn't sure at this stage what bearing current intensity played on forecasting possible paths or intensities.

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[Windspeed]

We're not going to be able to resolve this Cuba/no Cuba/how much of Cuba issue for a while, but it should not affect anybody's preparations at this point.  Plan for the potential of a category 4-5 hurricane and keep watching models and forecasts.

Yes debating semantics on model differences with respect to shapes of coastlines or land interaction with Cuba shouldn't outweigh the greater uncertainty that exists in potential track with this hurricane. We really have no better idea where or when the hard right turn will occur with Irma than the past 24 hours. And that is still likely to remain a huge uncertainty for several more days. Models may still shift greatly as interaction between troughs and the ridge evolves and is modeled with less degree of errors in placement and strength. The NHC track may change drastically with respect to potential landfall with Cuba and Florida even within 72 hrs due to basic geography. The best guess is a major hurricane impacting anywhere along the Florida peninsula to the Carolinas.