Major Hurricane Irma

[LakeEffectKing]

3 minutes ago, DopplerWx said:

12z nam looks like a near landfall in cuba at hr 24 FWIW

No it doesn't.

Edit:  My bad....did see "near landfall"....it is a near landfall by so has every other model...lol

[NJwx85]

2 minutes ago, DopplerWx said:

12z nam looks like a near landfall in cuba at hr 24 FWIW

Please stop posting inaccurate information. Irma does not make LF in Cuba on the 12z NAM.

[Cold Rain]

Probably going to be several hours before any bonafide strengthening trend is well underway, assuming she stays away from Cuba.  She will probably be "working out dry air" or "completing an ERC" or "clearing out the eye" for a healthy portion of the day.

[redbanknjandbigbasslakepa]

4 minutes ago, DopplerWx said:

12z nam looks like a near landfall in cuba at hr 24 FWIW

I can't trust the NAM for a clipper in the coastal plain, I can't take it serious for a cat 5 hurricane.

[NJwx85]

The NAM is going to be really far West this run, still hasn't made a Northerly turn at hr 36.

[RUNNAWAYICEBERG]

calm down. hr 23 gets awfully close to Cuban LF but 6z was way east so this means nada.

[Cold Rain]

3 minutes ago, NJwx85 said:

Please stop posting inaccurate information. Irma does not make LF in Cuba on the 12z NAM.

It wasn't inaccurate.  It's very possibly near enough to inhibit strengthening.  Is it right?  Should the NAM even be looked at?  Those are good questions.

[cwc]

9 minutes ago, Papa Joe said:

You see the train station? 

BTW - still not sure which key will catch the brunt, but if you can imagine, Marathon or Islamorada WILL be looking like this unless the storm develops a conscience and spins out to the GOM to die.

The building code in Monroe County is super strict.  I'm talking insane - people piss and moan when building or renovating, but this is the reason for the strict code.  New construction, at least since the '90s, required all structures to be designed by a Prof. Eng. or an architect.  There is a 35' height moratorium.  Etc., Etc.  Of course, there are a crap ton of mobile homes that will be toast, but the Keys are well prepared.

Less worried about the Keys than anywhere else in FL.  Yes, I know that picture was the result of a 20-25' storm surge.  But the keys aren't going to be wiped clean.

source: was a land surveyor in the keys in a prior life, and my dad was Key West's PE.

[CheeselandSkies]

I don't want to see another word about the NAM output in this thread. It. Is. Useless. for tropical systems.

Dry air, ERC, whatever, Irma still has the satellite presentation of a high-end major hurricane. Nothing "ragged" about it. Bottom line is everyone on both coasts of FL needs to be prepared for the possibility of taking a Cat 4-5 eyewall on the chin and evacuate if possible.

 

 

 

[NJwx85]

Just now, Cold Rain said:

It wasn't inaccurate.  It's very possibly near enough to inhibit strengthening.  Is it right?  Should the NAM even be looked at?  Those are good questions.

The post claimed that the NAM indicated a landfall on Cuba which is not correct. It's a close pass, which has far less implications than an actual landfall.

[psv88]

4 minutes ago, Cold Rain said:

It wasn't inaccurate.  It's very possibly near enough to inhibit strengthening.  Is it right?  Should the NAM even be looked at?  Those are good questions.

No. It had landfall in ANNAPOLIS last night. Enough said. It went from being the eastern outlier by far, to the western outlier, come on folks!

[SnowGoose69]

10 minutes ago, psv88 said:

Disagree here. Most of South Florida can handle cat 1 winds, cat 4 is different.

Probably can handle even up to 110-115.  If this went 70-80 miles west of the PBI-MIA corridor the worst problem would be surge in those prone areas of Miami and tree damage. There are actually a ton of non palms in those areas, particularly inland areas of Broward which were developed later where they planted non native trees.  Those will go down easily.   Palms usually don't go down until you reach 130-140 or higher although the tops generally blow off at 90-100 

[donsutherland1]

1 minute ago, Cold Rain said:

Probably going to be several hours before any bonafide strengthening trend is well underway, assuming she stays away from Cuba.  She will probably be "working out dry air" or "completing an ERC" or "clearing out the eye" for a healthy portion of the day.

If the recent runs of the GFS are right, strengthening would likely resume 6-12 hours from now (sometime after 18z and perhaps around 0z). In terms of historic climatology with hurricanes passing through the Florida Straits, deepening of 10 mb - 15 mb is common. That would bring Irma's central pressure down to 912 mb - 917 mb prior to landfall. There is a cluster of storms that saw 20 mb deepening, as well. So something in the vicinity of let's say 910 mb to 920 mb is probably reasonably likely. The GFS is more aggressive on the strengthening.

[AlaskaETC]

Just now, psv88 said:

No. It had landfall in ANNAPOLIS last night. Enough said.

People really need to understand that the NAM shouldn't be looked at all for this system. Mention it if you want, but we don't need posts dissecting each panel.

[Cold Rain]

1 minute ago, NJwx85 said:

The post claimed that the NAM indicated a landfall on Cuba which is not correct. It's a close pass, which has far less implications than an actual landfall.

I thought it said "near landfall".  Like LEK said, that's correct, though in line with most other models.  It was just a comment on the model, not a big deal.

Just now, psv88 said:

No. It had landfall in ANNAPOLIS last night. Enough said.

Agreed.

[lwg8tr0514]

4 minutes ago, RUNNAWAYICEBERG said:

Right. But the difference between a swfl LF and sefl  LF is significant in terms of population and business structures. The difference between 110mph in downtown MIA and 160mph  is massive.

136mph over lake Okeechobee, ummm don't think because of 30 miles with this storm you''l just be raking tree branches off your lawn.  I get what you are saying, that 30-50 swath of the MOST intense winds will be right on the eyewall, so yes I concede eye placement could mean someone losing their house or having 15k in repairs.  I'm not so sure based on 50+ years with these things that the re-curve doesn't happen sooner.  I moved out of South Florida in 2005 after Wilma and she I believe was supposed to miss the peninsula and curve into the GOM, well last minute she recurved and slammed right into the state.  Day before Halloween I think, and what was odd, after Wilma the weather cooled, I was cleaning up in a hoodie

[kenavp]

 

2 minutes ago, CheeselandSkies said:

I don't want to see another word about the NAM output in this thread. It. Is. Useless. for tropical systems.

Dry air, ERC, whatever, Irma still has the satellite presentation of a high-end major hurricane. Nothing "ragged" about it. Bottom line is everyone on both coasts of FL needs to be prepared for the possibility of taking a Cat 4-5 eyewall on the chin and evacuate if possible.

 

 

 

Eh, maybe this is nitpicking, but whether or not an eye is "ragged" is mostly an objective observation. It has nothing to do with whether or not everyone should be prepared for eventual possibilities. And certainly a couple amateur weather watchers on a forum like this noticing a weakening trend isn't going to change anyone's evacuation plans. 

[Cold Rain]

1 minute ago, donsutherland1 said:

If the recent runs of the GFS are right, strengthening would likely resume 6-12 hours from now (sometime after 18z and perhaps around 0z). In terms of historic climatology with hurricanes passing through the Florida Straits, deepening of 10 mb - 15 mb is common. That would bring Irma's central pressure down to 912 mb - 917 mb prior to landfall. There is a cluster of storms that saw 20 mb deepening, as well. So something in the vicinity of let's say 910 mb to 920 mb is probably reasonably likely. The GFS is more aggressive on the strengthening.

I think that's reasonable.  ERCs (and working out of dry air) tend to take longer than we think they will.  And as you mention, using history as a guide, it will be in a favorable location for strengthening.  Plus, by that time, it will have probably worked out whatever dry air it ingested.  I think steady-state is good for the next 12 hours or so, followed by a favorable window for legit strengthening.

[Hurricane Agnes]

3-day animated imagery of Irma convection overlaid on GOES-16 path -

 

[SnowGoose69]

2 minutes ago, lwg8tr0514 said:

136mph over lake Okeechobee, ummm don't think because of 30 miles with this storm you''l just be raking tree branches off your lawn.  I get what you are saying, that 30-50 swath of the MOST intense winds will be right on the eyewall, so yes I concede eye placement could mean someone losing their house or having 15k in repairs.  I'm not so sure based on 50+ years with these things that the re-curve doesn't happen sooner.  I moved out of South Florida in 2005 after Wilma and she I believe was supposed to miss the peninsula and curve into the GOM, well last minute she recurved and slammed right into the state.  Day before Halloween I think, and what was odd, after Wilma the weather cooled, I was cleaning up in a hoodie

I'm thinking the wind strength on the Euro in areas more than 30-40 miles from the center is probably overdone.  I do think we will see 70-80 gusts 100 at distances 60-70 miles east of the center but the 110-125 I'm seeing depicted is probably the Euro overestimating how efficiently those winds aloft will mix 

[bigtenfan]

3 minutes ago, SnowGoose69 said:

Probably can handle even up to 110-115.  If this went 70-80 miles west of the PBI-MIA corridor the worst problem would be surge in those prone areas of Miami and tree damage. There are actually a ton of non palms in those areas, particularly inland areas of Broward which were developed later where they planted non native trees.  Those will go down easily.   Palms usually don't go down until you reach 130-140 or higher although the tops generally blow off at 90-100 

My house in East Boca was built by a very well known national high end builder( not mentioning names but the initials are TB). In their infinite wisdom they put live oak trees both in the front and the back yards of my house. Spent my last day there(Tuesday) trying to figure out which way they will fall based on wind direction.

[Lookout]

9 minutes ago, CheeselandSkies said:

I don't want to see another word about the NAM output in this thread. It. Is. Useless. for tropical systems.

Dry air, ERC, whatever, Irma still has the satellite presentation of a high-end major hurricane. Nothing "ragged" about it. Bottom line is everyone on both coasts of FL needs to be prepared for the possibility of taking a Cat 4-5 eyewall on the chin and evacuate if possible.

 

 

 

Chill with the demands and attitude...and that goes for everyone else too. 

[catdaddyfalcon15]

Thank you. The NAM has screwed me so much for so many winters. 

11 minutes ago, redbanknjandbigbasslakepa said:

I can't trust the NAM for a clipper in the coastal plain, I can't take it serious for a cat 5 hurricane.

 

[wxeyeNH]

I want to comment on storm surge and the Miami area.  Storm surge is very dependent on the way the storm comes into the coast.  I saw the post about Continental shelf etc.  This is all great information but angle of storm or relitive position to any given area is most important. 

For the Miami area the Irma projected track is an absolutely worst case scenario.

1)  Irma has an extremely large wind field and strong east winds will first blow water into Key Biscayne for many hours.  

2)  A track west of Miami puts Miami Metro in the RFQ.  This is the dirty side with the strongest winds.

3) As Irma makes its closest approach to the west of the city the winds increase out of the due south.  This brings all the accumulated water from Key Biscayne Bay into S Miami and up the intercoastal

I am not as familiar with other bays such as Tampa Bay or the Ft Myers area.  I would think a track just to the east of those areas keep a north wind during the worst of the storm.  Remember that most of the area north of the Florida Keys is Everglades.  Very warm surface water temperatures and flat scrub lands.  Unlike a hurricane coming into hilly or mountainous terrain she will not quickly wind down. Actually Irma might be in a reorganizing stage as the storm will be moving north away from Cuba.  The core of destructive winds could continue quite far north.

Last thought:   I have family and friends in S Florida.  I have told them all to just stay put.  None are in tidal surge areas.  As long as your home is not in a flood prone area or does not have tall trees around it I feel most people will be fine.  Even with some 100mph gusts.  Long power outages along with Florida heat is going to be a big long term problem.  Unlike Harvey,  it is not going to be easy for people to just wake up on Monday and drive to the store to get water and supplies.  Millions will not have power and tree damage will be so widespread it will take quite awhile to clear.

All and all this hurricane will be the most destructive and widespread cane that Florida has ever seen.  I can think of no other analogy with a similar path and such a large wind shield.  

Best of luck to everyone down there....

[Papa Joe]

5 minutes ago, cwc said:

The building code in Monroe County is super strict.  I'm talking insane - people piss and moan when building or renovating, but this is the reason for the strict code.  New construction, at least since the '90s, required all structures to be designed by a Prof. Eng. or an architect.  There is a 35' height moratorium.  Etc., Etc.  Of course, there are a crap ton of mobile homes that will be toast, but the Keys are well prepared.

Less worried about the Keys than anywhere else in FL.  Yes, I know that picture was the result of a 20-25' storm surge.  But the keys aren't going to be wiped clean.

source: was a land surveyor in the keys in a prior life, and my dad was Key West's PE.

Thanks for the informed feedback, but if they get 20' storm surge (I'm going to "predict" 15') there will still be significant damage. It sounds like the new codes will certainly help with wind damage.

While the storm surge may not be as high as the '35 storm (for a variety of reasons), I expect it will be wider and affect more islands.

[TAP]

24 minutes ago, NJwx85 said:

As I posted earlier, most of the structures in SE Florida are built to handle strong Easterly winds, when you flip them around to Southwesterly, not so much. It's one of the reasons why Wilma was one of the most damaging hurricanes in recent history.

Sorry but this is totally untrue.  I am a structural engineer (licensed in FL, grew up in south MIA, and was at north edge of eye wall when Andrew hit).  Building codes including the FL building code require us to design for winds in multiple directions.

I have only researched back 60 years to the 1957 South Florida Building Code but see attached.  Requirements have been even more strict since then.

[JasonOH]

It didn't wait to strengthen.  Should be back to Cat 5 next update. (If it isn't flagged)

[Polka1]

33 minutes ago, lwg8tr0514 said:

-yes I concede eye placement could mean someone losing their house or having 15k in repairs.-

It seems you've answered the issue yourself.   Losing a house is a vastly different scenario than 15k of repairs.   

Also keep in mind the max winds near the core will likely be enough to exceed even the strictest building standards which would be important to all that new construction (especially those high rises).   Population density is far higher east and those max winds don't extend as far, so placement as it relates to population density will matter.   The population centers on the west side are a touch further north and one would hope the most extreme effects would be tempered by land interaction by then, if only minimally - plus the fact that they should be on the west side which should bring it down a bit more.  This doesn't even take into account storm surge differences.

It's going to be a mess either scenario, but the problems will be much worse if the eye wall is closer to Miami.

[tdp146]

8 minutes ago, TAP said:

Sorry but this is totally untrue.  I am a structural engineer (licensed in FL, grew up in south MIA, and was at north edge of eye wall when Andrew hit).  Building codes including the FL building code require us to design for winds in multiple directions.

I have only researched back 60 years to the 1957 South Florida Building Code but see attached.  Requirements have been even more strict since then.

Thank you for this. Do you have any similar information on what more recent codes are?

[LakeEffectKing]

1 minute ago, JasonOH said:

It didn't wait to strengthen.  Should be back to Cat 5 next update. (If it isn't flagged)

Rain contaminated....