Major Hurricane Irma

[SN_Lover]

4 minutes ago, Mdecoy said:

But to me, that option is still very much on the table at this point. Models are not reliable at this range and I think we need to be cautious.

By 0z tonight GFS could easily be showing a fish and it could be game over. Seen it MANY times. Not saying it will or that we should become complacent, but people have a tendency to take long range models as gospel and then get burned bad, over and over again. I think Tuesday and Wed is a good time to get serious about specifics.

This. if the 18z and 0z comes out with the SW/ULL weaker, than that should be a good indication to not feel to comfortable in a CONUS landfall. GFS barely pulled this one off. 

[Hoosier]

3 minutes ago, NJwx85 said:

Why is it that you could have all things pointing towards a US landfall, and people still try to pick it apart and find reasons for it not to happen?

While anything is possible at thing range, this is all about pattern recognition. Does the setup at H5 support the solution? Yes it does.

Dude, that's what any good forecaster does. Find the negatives in any setup.  It's not about saying it can't happen.

[donsutherland1]

11 minutes ago, WxWatcher007 said:

This will be a fascinating evolution. As I said in my local thread, we won't know surface details for a while but we may be able to get a better sense of the upper level pattern sooner, which will be a big piece in solving this puzzle. 

One thing that continues to bother me is the fact that the globals are almost lockstep IMO in showing a very deep system near the EC. Some of these pressures near and north of the Outer Banks are something to behold. Intensity forecasting for tropical systems leaves much to learn and be desired, but I find that kind of consistency to be...interesting...

I agree. This will be a remarkable event from a meteorological perspective. Considering the consistency of the guidance, the prospects of landfall are rising.

[larrye]

5 minutes ago, NJwx85 said:

Why is it that you could have all things pointing towards a US landfall, and people still try to pick it apart and find reasons for it not to happen?

While anything is possible at thing range, this is all about pattern recognition. Does the setup at H5 support the solution? Yes it does.

Because models can be unreliable at this range? Because their representation of the upper air features have been changing over the past bunch of runs and could change again? Yes, it looks (to me, a novice) like there is more run to run consistency and some degree of convergence between different models. But I don't know if there are many people who would say that "all things pointing towards a US landfall" right now.

[donsutherland1]

11 minutes ago, WxWatcher007 said:

This will be a fascinating evolution. As I said in my local thread, we won't know surface details for a while but we may be able to get a better sense of the upper level pattern sooner, which will be a big piece in solving this puzzle. 

One thing that continues to bother me is the fact that the globals are almost lockstep IMO in showing a very deep system near the EC. Some of these pressures near and north of the Outer Banks are something to behold. Intensity forecasting for tropical systems leaves much to learn and be desired, but I find that kind of consistency to be...interesting...

I agree. This will be a remarkable event from a meteorological perspective. Considering the consistency of the guidance, the prospects of landfall are rising.

[NJwx85]

1 minute ago, larrye said:

Because models can be unreliable at this range? Because their representation of the upper air features have been changing over the past bunch of runs and could change again? Yes, it looks (to me, a novice) like there is more run to run consistency and some degree of convergence between different models. But I don't know if there are many people who would say that "all things pointing towards a US landfall" right now.

You could say that if you were unable to make sense of what was going on. But to me, it makes perfect sense. And while it's going to be difficult to pin down the exact path for sometime, I don't see how it makes it OTS, at least not a hard right. 

Another option is that the trough pulls out faster, the energy wrapping around the backside is weaker, and Irma simply stalls near the Bahamas. If that happens then all bets are off.

[Hoosier]

1 minute ago, NJwx85 said:

Oh I agree, but for someone to say the odds of this going OTS are still at or near 50% seems stupid to me. I guess this is what makes forecasting so much fun, because in the end we could have all the right tools in hand and still not get it right.

However...a solid met once told me that models are tools, and that good pattern recognition is the key.

We are 8-9 days out or so.  As others have said, when your baseline for storms in this location overwhelmingly favors recurve, the idea of even giving it 50% odds of landfall (or 40%, or 30%) is saying something.

[csnavywx]

9 minutes ago, Hoosier said:

Dude, that's what any good forecaster does. Find the negatives in any setup.  It's not about saying it can't happen.

Exactly.

Especially in extreme scenarios.

[donsutherland1]

2 minutes ago, WxWatcher007 said:

I remain floored that the globals have exceptionally low central pressures north of the Outer Banks on the runs that hit our neck of the woods. Right or not, it is a sight to behold see and would be incredible to watch unfold (LF or OTS). 

Sure, but that's today. What is it going to look like 5 days from now? The orientation/strength/timing of the ridge-trough combo make all the difference in the world. I'm not yet confident enough to go all in on a complex 500h evolution this far out, but I can recognize that this is a higher than normal threat given the current potential setup. 

I have sometimes wondered whether Hugo might have reached category 5 strength if it had a few more hours to landfall. Irma might provide some insight.

[larrye]

3 minutes ago, NJwx85 said:

You could say that if you were unable to make sense of what was going on. But to me, it makes perfect sense. And while it's going to be difficult to pin down the exact path for sometime, I don't see how it makes it OTS, at least not a hard right. 

Another option is that the trough pulls out faster, the energy wrapping around the backside is weaker, and Irma simply stalls near the Bahamas. If that happens then all bets are off.

Perhaps not a hard right. And you may turn out to be right. But you also have to look at climatology. And like I said, the very features that you are using to make your judgement could change again over 9 days. If the models continue with this with some consistency as we get inside a 7 day, 6 day, 5 day period ... I think many will say that the probability is increased significantly. Right now, it's increased over what it was a few days ago ... yes.

[NJwx85]

ADT numbers have shot up quite a bit the last two hours. 

                     UW - CIMSS                     
              ADVANCED DVORAK TECHNIQUE       
                  ADT-Version 8.2.1                
         Tropical Cyclone Intensity Algorithm       

             ----- Current Analysis ----- 
     Date :  02 SEP 2017    Time :   161500 UTC
      Lat :   18:42:33 N     Lon :   43:37:55 W

     
             Final T#  Adj T#  Raw T# 
                5.3     5.6     5.6

 Estimated radius of max. wind based on IR : 12 km

[csnavywx]

1 minute ago, donsutherland1 said:

I have sometimes wondered whether Hugo might have reached category 5 strength if it had a few more hours to landfall. Irma might provide some insight.

The traditional peak location is right as the hurricane starts to recurve. SSTs are typically near peak, shear is still low and outflow channels are usually opening up as the hurricane finds the weakness in the ridge. Incidentally, that's about where the EC and GFS bottom out the pressure. The GFS is obviously overdone, but the EC has been dropping into the 920s there, so it may not be totally out to lunch.

[SN_Lover]

1 minute ago, larrye said:

Perhaps not a hard right. And you may turn out to be right. But you also have to look at climatology. And like I said, the very features that you are using to make your judgement could change again over 9 days. If the models continue with this with some consistency as we get inside a 7 day, 6 day, 5 day period ... I think many will say that the probability is increased significantly. Right now, it's increased over what it was a few days ago ... yes.

Speaking of climo, here are the top analog tracks... I see a "I" in there!

[packfan98]

By looking at the 12z GEFS mean, it looks as though there is a split between a northern and southern solution:

[Windspeed]

I have sometimes wondered whether Hugo might have reached category 5 strength if it had a few more hours to landfall. Irma might provide some insight.

 

I think it's quite possible. That's exactly the type of setup you would want to see to get a Cat 5 into the Carolinas.

 

A rapidly intensifying hurricane being squeeze between an strong mid-to-upper low to its WSW and a strong 500mb ridge to its ENE. Fast moving in a low shear environment with amazing upper level outflow channels to its northwest and southeast.

 

[MattPetrulli]

The ceiling is the roof with this one

Unsettling to think about since it'll probably at least  make a close pass by the US. 

[Jackstraw]

3 minutes ago, SN_Lover said:

Speaking of climo, here are the top analog tracks... I see a "I" in there!

I couldn't imagine reading this board if this thing pulled an Esther lol

[packfan98]

from Ryan M. on twitter:

[Hazey]

Pattern recognition is not to be confused with model recognition. The pattern the models are showing in day 6-8 might be different when we get to that point.

[HKY1894]

Hard to weight analogs much considering how anomalous the atlantic ridging is compared to climo 

[NJwx85]

Looks to me like most of the 12z GEFS members show an East coast hit. Some as far South as FL

[Windspeed]

I think it's quite possible. That's exactly the type of setup you would want to see to get a Cat 5 into the Carolinas. 

A rapidly intensifying hurricane being squeeze between an strong mid-to-upper low to its WSW and a strong 500mb ridge to its ENE. Fast moving in a low shear environment with amazing upper level outflow channels to its northwest and southeast.

 

I should reiterate that I am not saying we will see the same setup with Irma but it's too early to know how that cutoff feature evolves IRL, if at all, and what its position will be.

[SnoSki14]

You can't use the climo argument under such an anamalous pattern otherwise storms like Sandy should have gone OTS.

 

[NorthArlington101]

Looks to me like most of the 12z GEFS members show an East coast hit. Some as far South as FL

[donsutherland1]

9 minutes ago, csnavywx said:

The traditional peak location is right as the hurricane starts to recurve. SSTs are typically near peak, shear is still low and outflow channels are usually opening up as the hurricane finds the weakness in the ridge. Incidentally, that's about where the EC and GFS bottom out the pressure. The GFS is obviously overdone, but the EC has been dropping into the 920s there, so it may not be totally out to lunch.

Something in the 920s would be very impressive. Like you, I suspect that the GFS is overdone.

[Jackstraw]

2 minutes ago, Windspeed said:

7 minutes ago, Windspeed said:

I think it's quite possible. That's exactly the type of setup you would want to see to get a Cat 5 into the Carolinas. 

A rapidly intensifying hurricane being squeeze between an strong mid-to-upper low to its WSW and a strong 500mb ridge to its ENE. Fast moving in a low shear environment with amazing upper level outflow channels to its northwest and southeast.

 
 

I should reiterate that I am not saying we will see the same setup with Irma but it's too early to know how that cutoff feature evolves IRL, if at all, and what its position will be.

Not to mention model skills at forecasting cutoff's, especially this far out, are not that impressive.

[Wow]

12Z GEFS by 228 hrs have a cluster of members over the SE, and another off the NE/MA coast.  

[packfan98]

1 minute ago, Wow said:

12Z GEFS by 228 hrs have a cluster of members over the SE, and another off the NE/MA coast.  

and it looks like only one member recurves...

[Tibet]

6 minutes ago, Hazey said:

Pattern recognition is not to be confused with model recognition. The pattern the models are showing in day 6-8 might be different when we get to that point.

Thank you, why are we all getting uppity about what the models are "suggesting" at this range... just about none of us would be looking at what the models these are spitting out... let alone accepting it with any sort of confidence. A week out is a crapshoot, at all levels.

[Foulkey]

Question: it's been a fairly cool summer in New England. Are we assuming the cooler ocean water will knock Irma down quite a bit before any potential NYC landfall?

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