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Major Hurricane Irma- STORM MODE

stormtracker

By stormtracker,
in Tropical Headquarters

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jpeters3

jpeters3

Posted
Posted
12 minutes ago, LakeEffectKing said:

From the NHC at 11pm last night...

If the eye continues to move over the Cuban Keys and does not move
inland over the main island of Cuba, then Irma would likely not
lose much intensity during the next day or so.  As we've stated
many times, fluctuations in intensity are likely during the next 36
hours due to possible and unpredictable eyewall replacement cycles.
After 36 hours, there are some indications that vertical shear may
increase over the hurricane, and a little more weakening is
anticipated at that time.  Because of the concerns in the track
forecast noted above, Irma would be able to maintain a strong
intensity for a longer period of time if the center stays off the
west Florida coast.  Regardless, Irma is still expected to be a
dangerous hurricane as it approaches the Florida Keys and the west
coast of Florida through 48 hours.
 

There has been a secondary wind max not too far from the IEW....I think this played just as important of a part of the weakening (and maybe additive) as was the Cuban proximity.


Lets just call a spade a spade.  A storm interacts with landmass for an extended period of time and weakens.  The simplest and most likely explanation was the land interaction (there doesn't appear to be a well-defined concentric eyewall on radar).  

Interesting call to basically play down the potential effect of the land interaction on storm intensity in the forecast (which in my opinion goes against intuition).  

 

Edit: If the storm struggles to re-intensify, this may end up being the best possible outcome for a Florida landfall.  The northern stretch of Cuba that the eye has been tracking along looks sparsely populated, so hopefully the death and destruction in Cuba is minimized.  A few more hours of land interaction could result in a category 1/2 hurricane landfalling on FL rather than a category 4/5.  This is something we should be excited about, right?  I'm certainly hoping that my friends who live on the southwestern coast of Florida don't lose their homes.

There is probably a chance for strengthening between Cuba and Florida, but that is probably strongly dependent on nuances of the timing of shear interaction with the storm and the degree of internal core disruption.  I for one hope this doesn't happen - Harvey was enough of a mega financial disaster for one year.

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LakeEffectKing

LakeEffectKing

Posted
Posted
5 minutes ago, jpeters3 said:


Lets just call a spade a spade.  A storm interacts with landmass for an extended period of time and weakens.  The simplest and most likely explanation was the land interaction (there doesn't appear to be a well-defined concentric eyewall on radar).  

Interesting call to basically play down the potential effect of the land interaction on storm intensity in the forecast (which in my opinion goes against intuition).  

Not at all "downplaying" the interaction"....I called for a 20mb drop, and a about a 20mph reduction last night....but to assume that land interaction all of a sudden was 100% of it's weakening, is black or white thinking, when internal processes are always on going...the eye/core had not completely recovered to a "stadium" look prior to the interaction with land....thus, IMO, was a bit more susceptible to the close proximity of the land interaction.  Really semantics at this point....

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forecasterjack

forecasterjack

Posted
Posted
Just now, psuhoffman said:

As long as he doesn't keep doing it, for those of us new to that site it's the first chance to test it out on a major event so I get the excitement and I found the links helpful. But I see your point too. 

That was my intention :) I think we have some really great tools to help track Irma, and I wanted everyone to know about those in case they wanted to use them. We're a new site, so not many folks know about us yet. I'll just post the images if the links are a problem

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forecasterjack

forecasterjack

Posted
Posted
2 minutes ago, JoMo said:

That's a ginormous eye showing up at the end of the HRRR run the last few hours after it heads back over water. 

Large but kinda disorganized. And weighted towards the side with more dry air/shear. Think that might be a bit of a model fluke. Curious if anyone has any input as to what might be causing that representation 

us_model-en-087-0_modusarpd_2017090912_18_5797_482.png

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jpeters3

jpeters3

Posted
Posted
2 minutes ago, LakeEffectKing said:

Not at all "downplaying" the interaction"....I called for a 20mb drop, and a about a 20mph reduction last night....but to assume that land interaction all of a sudden was 100% of it's weakening, is black or white thinking, when internal processes are always on going...the eye/core had not completely recovered to a "stadium" look prior to the interaction with land....thus, IMO, was a bit more susceptible to the close proximity of the land interaction.  Really semantics at this point....


Ok gotcha.  I misunderstood.

I do wonder if there is some westerly shear at play as well, given the restriction of the outflow on the storm's western flank.  There are a lot of complex dynamics at work in these situations where the core hovers near shore and there is at least mildly mountainous terrain (i think there are ~ 300-400 meter hills along this part of the island).

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jpeters3

jpeters3

Posted
Posted
3 minutes ago, forecasterjack said:

Large but kinda disorganized. And weighted towards the side with more dry air/shear. Think that might be a bit of a model fluke. Curious if anyone has any input as to what might be causing that representation 

us_model-en-087-0_modusarpd_2017090912_18_5797_482.png


Looks like the storm is straddling the HRRR's southern domain boundary, so I wouldn't give much credence to its solution right now.  Basically everything on the right flank of the storm is bing passed in from the RAP, which parameterizes convection.  In contrast, explicitly resolved convection is being advected southward on the storm's right flank.  I suspect that's what gives the storm a funny look here.

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LakeEffectKing

LakeEffectKing

Posted
Posted
1 minute ago, jpeters3 said:


Ok gotcha.  I misunderstood.

I do wonder if there is some westerly shear at play as well, given the restriction of the outflow on the storm's western flank.  There are a lot of complex dynamics at work in these situations where the core hovers near shore and there is at least mildly mountainous terrain (i think there are ~ 300-400 meter hills along this part of the island).

From CMISS, I don't think so...maybe a touch more of an influence because of it's fighting whatever impacts land is having...

wg8shr.GIF

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qg_omega

qg_omega

Posted
Posted
31 minutes ago, LakeEffectKing said:

From the NHC at 11pm last night...

If the eye continues to move over the Cuban Keys and does not move
inland over the main island of Cuba, then Irma would likely not
lose much intensity during the next day or so.  As we've stated
many times, fluctuations in intensity are likely during the next 36
hours due to possible and unpredictable eyewall replacement cycles.
After 36 hours, there are some indications that vertical shear may
increase over the hurricane, and a little more weakening is
anticipated at that time.  Because of the concerns in the track
forecast noted above, Irma would be able to maintain a strong
intensity for a longer period of time if the center stays off the
west Florida coast.  Regardless, Irma is still expected to be a
dangerous hurricane as it approaches the Florida Keys and the west
coast of Florida through 48 hours.
 

There has been a secondary wind max not too far from the IEW....I think this played just as important of a part of the weakening (and maybe additive) as was the Cuban proximity.

The NHC forecast from last night at 11pm, about 10 hrs ago:

  

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 22.1N  77.7W  140 KT 160 MPH
 12H  09/1200Z 22.6N  79.1W  140 KT 160 MPH
 24H  10/0000Z 23.3N  80.6W  135 KT 155 MPH
 36H  10/1200Z 24.5N  81.4W  130 KT 150 MPH
 48H  11/0000Z 26.5N  81.9W  115 KT 130 MPH...INLAND
 72H  12/0000Z 31.6N  83.8W   50 KT  60 MPH...INLAND
 96H  13/0000Z 35.0N  87.0W   25 KT  30 MPH...INLAND
120H  14/0000Z 35.5N  87.5W   20 KT  25 MPH...POST-TROP/INLAND

Probably the worst 12hr intensity forecast from NHC in a very long long time.
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qg_omega

qg_omega

Posted
Posted
12 minutes ago, LakeEffectKing said:

Not at all "downplaying" the interaction"....I called for a 20mb drop, and a about a 20mph reduction last night....but to assume that land interaction all of a sudden was 100% of it's weakening, is black or white thinking, when internal processes are always on going...the eye/core had not completely recovered to a "stadium" look prior to the interaction with land....thus, IMO, was a bit more susceptible to the close proximity of the land interaction.  Really semantics at this point....

NHC called for no reduction last night at 11pm:

  

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 22.1N  77.7W  140 KT 160 MPH
 12H  09/1200Z 22.6N  79.1W  140 KT 160 MPH
 24H  10/0000Z 23.3N  80.6W  135 KT 155 MPH
 36H  10/1200Z 24.5N  81.4W  130 KT 150 MPH
 48H  11/0000Z 26.5N  81.9W  115 KT 130 MPH...INLAND
 72H  12/0000Z 31.6N  83.8W   50 KT  60 MPH...INLAND
 96H  13/0000Z 35.0N  87.0W   25 KT  30 MPH...INLAND
120H  14/0000Z 35.5N  87.5W   20 KT  25 MPH...POST-TROP/INLAND
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jpeters3

jpeters3

Posted
Posted
2 minutes ago, LakeEffectKing said:

From CMISS, I don't think so...maybe a touch more of an influence because of it's fighting whatever impacts land is having...

wg8shr.GIF

 

You might be right about the land interaction thing.  If the land interaction slows the system motion relative to the mean flow, that would result in a net increase in shear.

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Kelathos

Kelathos

Posted
Posted
10 minutes ago, JoMo said:

That's a ginormous eye showing up at the end of the HRRR run the last few hours after it heads back over water. 

I expect, if that happens, it would be a result of collapsing the IEW and having the next band take over acting as a OEW.

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F-5

F-5

Posted
Posted

Looking at the shape of the Cuban shoreline, Irma had a burst of intensification shortly after being more over open water as she went past that little dip in the shoreline.  Possible indicator the core is still in good shape or maybe just coincidence? 

 

Looks like about 4-6 hours until the shoreline starts flattening to a more westerly orientation and barring a jog, Irma will start separating from the coast by early afternoon.

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jpeters3

jpeters3

Posted
Posted
2 minutes ago, LakeEffectKing said:

From CMISS, I don't think so...maybe a touch more of an influence because of it's fighting whatever impacts land is having...

wg8shr.GIF

 

You might be right about the land interaction thing.  If the land interaction slows the system motion relative to the mean flow, that would result in a net increase in shear.

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WeatherMimmi

WeatherMimmi

Posted
Posted

Can someone tell a novice at what point and/or time does the current track indicate we should see the N turn ? I guess what I'm asking , as I don't understand a lot of what is being said as this terminology is way above my skill set, but how do i tell when she misses a modeled point  prediction and she is more west  than current euro model. ?

 

Way back  in 1985 Hurricane Elana was very hard to figure out and all over the GOM. I'm sure technology is better, but this has also been all over the place from totaly east to Fl to now the GOM which was  very unlikely from earler posts.  

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LakeEffectKing

LakeEffectKing

Posted
Posted
3 minutes ago, qg_omega said:

The NHC forecast from last night at 11pm, about 10 hrs ago:

  


FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 22.1N  77.7W  140 KT 160 MPH
 12H  09/1200Z 22.6N  79.1W  140 KT 160 MPH
 24H  10/0000Z 23.3N  80.6W  135 KT 155 MPH
 36H  10/1200Z 24.5N  81.4W  130 KT 150 MPH
 48H  11/0000Z 26.5N  81.9W  115 KT 130 MPH...INLAND
 72H  12/0000Z 31.6N  83.8W   50 KT  60 MPH...INLAND
 96H  13/0000Z 35.0N  87.0W   25 KT  30 MPH...INLAND
120H  14/0000Z 35.5N  87.5W   20 KT  25 MPH...POST-TROP/INLAND

Probably the worst 12hr intensity forecast from NHC in a very long long time.

Yes, they certainly over zealous...I really believe they were banking on a continued "strengthening" phase (via EWRC almost complete) as it was approaching the Cuban landmass...in a sense, a draw between the negating factors and the intensification phase ATT...

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Lookout

Lookout

Posted
Posted
28 minutes ago, jasons said:

Same thing happened to Ike, and Ike was never the same.

a little different though...Ike had a lot more interaction with cuba...it went across/interacted with.. the entire length  of cuba...

Ike_2008_track.png

 

 

FWIW, right now irma is a bit north of the 0z euro last night...and if it continues on this path it would be significantly north...not in miles per se but just the fact the euro had irma actually fully inland over the next few hours. The reason i find this is interesting is that irma might/should be in a little better shape than the euro showed it to be when it moves away from cuba which is important i think considering how much the euro restrengthens it...929 mbs at landfall. 

 

 

 

 

us_model-en-087-0_modez_2017090900_15_1457_149.png

us_model-en-087-0_modez_2017090900_18_1457_149.png

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