Major Hurricane Irma

[olafminesaw]

Why does the eye appear off center?

 

[LibertyBell]

4 hours ago, 40/70 Benchmark said:

I don't think this point has been emphasized enough. The gridlock is going to be incomprehensible as folks try to escape northward out of the peninsula...they need to impose a travel deadline.

Yes, Ray, Rita showed what kind of a disaster the evacuation itself can become!

[forecasterjack]

4 minutes ago, Crazy4Wx said:

I have been asking this question for a little bit now. Anyone have an idea of what the surge + waves rolling into Miami would be in a worst case trajectory?

Don't know about surge which depends on track and local geography, but ECMWF wave data shows significant wave heights approaching 50 feet https://weather.us/model-charts/euro/803-w-241-n/sign-wave-height-direction-ft/20170910-1200z.html

[andyhb]

3 minutes ago, LibertyBell said:

I saw a documentary about Andrew a few years ago and it was scary how much damage it caused.  The only other time I've seen that level of destruction was Haiyan in the Philippines (which I believe was the strongest landfalling hurricane on record at 190 mph, just 5 mph shy of its peak at 195 mph) and the Indonesian Tsunami in 2004.   I didn't see any documentaries about Mitch in 1998 although that must've caused the same kind of catastrophic damage down in Central America (over 10,000 deaths!)  Some of the scenes in the documentary were right out of something out of the Planet of the Apes, with deserted streets and buildings leveled everywhere and no signs of people anywhere but roving bands of chimps and orangutans that had escaped from a zoo during the storm running down the streets of deserted towns and cities.

Mitch's damage was basically entirely due to flooding.

[Neblizzard]

2 minutes ago, olafminesaw said:

Why does the eye appear off center?

 

She encountered a bit of shear on the western side this morning. The 5pm advisory has shown the pressure drop ( now 914 mb) so I predict she will intensify overnight.

[SnowGoose69]

Does anyone know of any surge maps for the intracoastal waterway between Miami and Ft. Lauderdale?   I would assume the closer you are to one of the ocean inlets the worse it would be but I'm not sure if there is any precedent to really know 

[LibertyBell]

1 minute ago, andyhb said:

Mitch's damage was basically entirely due to flooding.

Thanks Andy, was that due to orographic enhancement when it interacted with the mountains down there?

[Crazy4Wx]

Just now, forecasterjack said:

Don't know about surge which depends on track and local geography, but ECMWF wave data shows significant wave heights approaching 50 feet https://weather.us/model-charts/euro/803-w-241-n/sign-wave-height-direction-ft/20170910-1200z.html

So that is 50 ft waves on top of the Storm Surge...so is that 70+ ft?

Also, I have trouble seeing the comparison to Andrew, since it didn't hit Cat 5 status till very late...in the Bahamas. Irma has been a Cat 5 since before the Leewards and has had a long time to build up wave heights. 

[donsutherland1]

41 minutes ago, Crazy4Wx said:

I have been asking this question for a little bit now. Anyone have an idea of what the surge + waves rolling into Miami would be in a worst case trajectory?

Here's a paper that might provide some insight, as it covers two large Category 4 hurricanes that made Florida landfall: http://journals.ametsoc.org/doi/pdf/10.1175/bams-84-10-1367\

Another link (see slide 37): https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwjtypmgxpHWAhVl8IMKHe_NDR4QFghUMAY&url=http%3A%2F%2Fwww.aoml.noaa.gov%2Fhrd%2Fhurdat%2Fpresentations%2Firr_040819.ppt&usg=AFQjCNEoClRe2T_0R_MDsAir4SDUSDythA

[jpeters3]

3 minutes ago, StormChaser4Life said:

First time in many years we have seen three hurricanes lined up in the Atlantic and Gulf. And one of those recording breaking. But back on topic Irma really is remarkable holding this intensity so long. And remaining so symmetrical. Pretty rare esp in Atlantic for very long duration. Here's my question though. If the atmospheric conditions look the same the next few days and water temps get warmer and if it avoids any major land interaction, why can't Irma hold as a high end cat 5 and not weaken as quick as NHC has it? I get ERC's will cause fluctuation and I know as it nears the US some shear will be introduced but up till then I'm not so sure this will weaken as quick as NHC has it

Shear is forecasted to pick up by Sat as the system starts to interact with the midlatitude baroclinic zone:

 

http://rammb.cira.colostate.edu/products/tc_realtime/products/storms/2017AL11/DIAGPLOT/2017AL11_DIAGPLOT_201709061800.png

[andyhb]

4 minutes ago, LibertyBell said:

Thanks Andy, was that due to orographic enhancement when it interacted with the mountains down there?

Yes. Just stalled and dumped for days (sort of Harvey-esque) and led to catastrophic flash flooding and mudslides over Honduras, Nicaragua, etc.

[Chargers09]

3 minutes ago, Neblizzard said:

She encountered a bit of shear on the western side this morning. The 5pm advisory has shown the pressure drop ( now 914 mb) so I predict she will intensify overnight.

Old image, as well. 

[Radtechwxman]

Just now, jpeters3 said:

Shear is forecasted to pick up by Sat as the system starts to interact with the midlatitude baroclinic zone:

 

http://rammb.cira.colostate.edu/products/tc_realtime/products/storms/2017AL11/DIAGPLOT/2017AL11_DIAGPLOT_201709061800.png

I know that. But I'm saying they have it weakening even before that

[hlcater]

3 minutes ago, SnowGoose69 said:

Does anyone know of any surge maps for the intracoastal waterway between Miami and Ft. Lauderdale?   I would assume the closer you are to one of the ocean inlets the worse it would be but I'm not sure if there is any precedent to really know 

http://noaa.maps.arcgis.com/apps/MapSeries/index.html?appid=d9ed7904dbec441a9c4dd7b277935fad&entry=1

[forecasterjack]

1 minute ago, Crazy4Wx said:

So that is 50 ft waves on top of the Storm Surge...so is that 70+ ft?

Also, I have trouble seeing the comparison to Andrew, since it didn't hit Cat 5 status till very late...in the Bahamas. Irma has been a Cat 5 since before the Leewards and has had a long time to build up wave heights. 

That might be a little high, significant wave height is the height of the highest third of all the waves from crest to trough (which is below average sea level). So a 50 foot wave will extend 25 feet above the mean sea level. Also not sure if a 20 foot surge is on the table. Either way, it's a bad situation. 

[forecasterjack]

2 minutes ago, jpeters3 said:

Shear is forecasted to pick up by Sat as the system starts to interact with the midlatitude baroclinic zone:

 

http://rammb.cira.colostate.edu/products/tc_realtime/products/storms/2017AL11/DIAGPLOT/2017AL11_DIAGPLOT_201709061800.png

Based on ECMWF simulated IR, it definitely looks to be working on transitioning to an extratropical system by the time it arrives in the Carolinas https://weather.us/model-charts/euro/724-w-263-n/sat-ir-bright-temperature-1079mu/20170911-1800z.html

[das]

Mesovorticies really starting to stand out on TDWR 1 minute scans.  And, there's plenty of interaction between the eyewall and the feeder bands.  Does not look like an ERC is imminent.  

[LibertyBell]

5 minutes ago, StormChaser4Life said:

I know that. But I'm saying they have it weakening even before that

Weakening is relative though, NHC has it at 145 mph at landfall, worst since Andrew.  I don't know if there is a perceptible amount of difference in damage caused by a 145-150 mph Cat 4 vs a 160 mph Cat 5.  Also remember that Irma will be pushing along the surge it raised from when she was 185 mph.

[friedmators]

[Random Chaos]

Latest IR - bit larger than 24 hrs ago, not fully recovered from the shear earlier, but better than a couple hours ago:

 

[gymengineer]

The Miami 1926 hurricane and Ft Lauderdale 1947 hurricane storm surge were in the 11-14 ft range-- those were head on hits. Andrew's 16.9 ft is the record surge for the east coast of Florida. 

[TriPol]

11 minutes ago, SnowGoose69 said:

Does anyone know of any surge maps for the intracoastal waterway between Miami and Ft. Lauderdale?   I would assume the closer you are to one of the ocean inlets the worse it would be but I'm not sure if there is any precedent to really know 

 

I think Mar-A-Lago is going to get hit pretty hard.

[bluewave]

South Florida needs that track to shift since they aren't remotely prepared  for a hurricane of this magnitude.

https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/08/23/bryan-norcross-hero-of-hurricane-andrew-florida-is-not-remotely-prepared-for-the-next-one/

[salbers]

16 minutes ago, cwc said:

http://frances-a.cs.fiu.edu/gic/

 

Storm surge projector for MIA

In the past I've seen SLOSH (and PSurge) maps updated for the realtime storm. Unsure if they are still being produced.

[Silver Meteor]

7 minutes ago, Crazy4Wx said:

So that is 50 ft waves on top of the Storm Surge...so is that 70+ ft?

Also, I have trouble seeing the comparison to Andrew, since it didn't hit Cat 5 status till very late...in the Bahamas. Irma has been a Cat 5 since before the Leewards and has had a long time to build up wave heights. 

A wave cannot be higher than the water is deep. At about 80% of the water's depth the wave has no choice but to break. This is why large ocean waves never reach the coast. If you can get a good vantage point with good visibility you can even see "near shore" waves break on the horizon before reforming to become final beach breakers.

[Hurricane Agnes]

Clear shot of the eye wall just missing PR.

 

[beanskip]

18z GFS basically giving back the southern trending of the 12z run vs. 6z. In other words, the 18z is almost right on top of the 6z position through 48 hours. 

[Radtechwxman]

15 minutes ago, LibertyBell said:

Weakening is relative though, NHC has it at 145 mph at landfall, worst since Andrew.  I don't know if there is a perceptible amount of difference in damage caused by a 145-150 mph Cat 4 vs a 160 mph Cat 5.  Also remember that Irma will be pushing along the surge it raised from when she was 185 mph.

I get that. And not underplaying it by any means. But just saying I think it could be stronger than that

[EasternLI]

Goes 16 is just amazing right now.

http://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=goes-16/mesoscale_01_band_02_sector_05&width=1000&height=1000&number_of_images_to_display=40&loop_speed_ms=80

 

[Wow]

18z GFS back to 6z and 0z positions.  BTW, Jose is trending much faster.