ATL: IRMA - Post-Tropical - Discussion

[TheStormExpert]

For those thinking SE Florida is out of the woods.

 https://twitter.com/johnmoralesnbc6/status/906169685993021440

Agree, but if this track continues to shift W at some point you can at least report what the reality is.

Id venture to say with .5 degree shifts that the NHC is pretty much zeroed in... John is pretty unfiltered. Even the new track has Cat 2/3 winds over Metro SE FL

Unfortunately does that include the West Palm area?

[Jevo]

What the spaghetti line with Irma should look like based on a 45mi eye vs a silly spaghetti line that people get hung up on.

Don't hate on my MS Paint skill!



This is more accurate

[Patrick99]

For those thinking SE Florida is out of the woods.

 https://twitter.com/johnmoralesnbc6/status/906169685993021440

Agree, but if this track continues to shift W at some point you can at least report what the reality is.

Id venture to say with .5 degree shifts that the NHC is pretty much zeroed in... John is pretty unfiltered. Even the new track has Cat 2/3 winds over Metro SE FL

Which, ever since this whole debacle started, I said I would gladly take (comparatively speaking) and call it a day. I know Cat 3 is no picnic, but it's so much better than having 185mph of Cat 5 inner eyewall directly overhead. Not sure why this is a controversial opinion.

[Aric Dunn]

radar showing no more inner eye convection. what we see on IR is the left over cloud debris from that recent little bit and it will fade quickly. assuming no more convection occurs with the inner. it should be nothing but a clearing eye and some slow deepeing from here on out.

[Aric Dunn]

What the spaghetti line with Irma should look like based on a 45mi eye vs a silly spaghetti line that people get hung up on.

Don't hate on my MS Paint skill!



This is more accurate

the other one is still not wide enough lol..

[Kat5]

What the spaghetti line with Irma should look like based on a 45mi eye vs a silly spaghetti line that people get hung up on.

Don't hate on my MS Paint skill!



This is more accurate

the other one is still not wide enough lol..

And just look at the keys.... they'll be under water regardless.

[tarheelprogrammer]

This storm is so large that the worst part of the storm extends to both coasts of Florida. Surge will be terrible in many places. Please do not take this lightly. Stay safe everyone, and prayers your way from Wilmington, NC.

[Langinbang187]

My god this is one of the longest EWRC's I've ever seen. As long as that inner eyewall refuses to collapse we should continue to see gradual pressure rises.

[GCANE]

Just an FYI.
Mexico was hit by a 8.1 quake a few hours ago.
Biggest in a century.
Small tsunami's reported in the Pacific.

[NDG]

Forecast from 72 hours ago. Had it as a 135 kt cat 4 this morning. Verified as a 130 kt cat 4.



Had a 46 nmi error vs the 5 year average of 110 nmi.

Impressive how their 72hr forecast has verified, I am sure they are thanking the Euro for it

[Jimsot]

Thanks this was quite helpful for here in Roebuck SC. Weather-underground and Accu-weather where showing awfully high winds for here that didn't seem to jive with the NHC Irma track off to our west. The NWS Tabular seemed more realistic. I hope they are correct!

I'm sure many of you have used this resource before, but for those who are inland like myself, and who are still anxiously following forecast wind speeds, this tabular forecast is very helpful:

http://forecast.weather.gov/MapClick.php?w0=t&w1=td&w2=hi&w3=sfcwind&w3u=1&w4=sky&w5=pop&w6=rh&w7=rain&w8=thunder&w10u=0&w12u=1&w13u=1&AheadHour=0&FcstType=digital&textField1=28.3577&textField2=-82.6995&site=all&unit=0&dd=&bw=&AheadDay.x=60&AheadDay.y=6&AheadDay=48

[txwatcher91]

Something to think about here, with so much of Florida being swamp/wetlands and ocean on both sides... a storm the size of Irma will have no problems pulling in moisture and weakening will probably be fairly slow until shear really starts kicking in. I took a look at the Euro max wind gusts and it's portraying 100mph gusts all the way to central Georgia and across a large part of the state. Most of the FL peninsula will likely see winds gusting well over hurricane force and places like Georgia and South Carolina might too. That's a huge swath of downed trees and power lines...

[KC7NEC]

Urgent, Please share this with those in Irma's path:

Anyone in the path of this Hurricane needs to download the "Firechat App" on iPhone and Android. The app is a messaging and communications tool that DOES NOT require a cellular connection. It works by creating a Bluetooth store-and-forward mesh network. The important thing to note is the more users with the app active in the area the better a message can travel out to reach a network connection. This could be a vital way to get messages out if the cell network is unusable.

For information or links to the app download visit: https://www.opengarden.com/firechat.html

[caneman]

Forecast from 72 hours ago. Had it as a 135 kt cat 4 this morning. Verified as a 130 kt cat 4.



Had a 46 nmi error vs the 5 year average of 110 nmi.

Impressive how their 72hr forecast has verified, I am sure they are thanking the Euro for it

And UKMET. It's been the Most cosnistent with west trend

[stormreader]

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

Major Hurricane Irma [11L]
Track, Intensity, and Impact [TI2] Guidance
15z, September 18, 2017
$$

Current Information (11am, NHC, 6hr trend in parenthesis)
Winds: 130kts / 150mph
Pressure: 927mb
Movement: WNW (285) at 14mph

Track
Irma will continue to move on a west-northwesterly heading over the next twenty-four or so hours, and the center may pass within just a couple miles of the Cuban coastline. Beyond twenty-four hours, Irma will begin to feel the influence of an upper-level trough located in the northeastern United States, and model guidance unanimously agrees that at some point, Irma will turn to the north. Model consensus is fairly high, although shifting, that Irma’s center will make landfall in southern Florida, before tracking on a north-northwesterly heading into Georgia. After that, the guidance diverges on the eventual fate of Irma’s remnants.

Uncertainty remains on several extremely important details. How close will Irma come to Cuba? When will Irma turn to the north? How much time will the storm have over the boiling hot waters of the Florida Straight? These are things that, unfortunately, we may not know a real answer to, beyond an estimate, until they happen.

Intensity
11am Friday [Current] - 130kts / 150mph
11am Saturday [+24] - 135kts / 155mph
(Landfall Intensity - 145kts / 165mph)
11am Sunday [+48] - 120kts / 135mph
11am Monday [+72] - 70kts / 80mph
11am Tuesday [+96] - 30kts / 40mph
11am Wednesday [+120] - 25kts / 30mph

If the track of Irma is somewhat uncertain, the intensity is doubly so. The storm maintained category five intensity for a record length of time, but weakened to a still-catastrophic category four early this morning while undergoing an eyewall replacement cycle, or EWRC. This EWRC appears to be complete, and the model consensus shows pressures ceasing to rise by later tonight, and dropping during the day Saturday and all the way up until landfall. The next forty-eight hours will bring Irma’s core over an area of extremely high ocean heat content, with sea surface temperatures ranging from 30 to 32 degrees celcius. Shear will be minimal until landfall, and dry air should not have an impact until after the +48 forecast period.

The only factor that I can see keeping a lid on Irma is a major one; land interaction. Should the hurricane actually make landfall in Cuba, it is possible it may weaken further, perhaps to a category three hurricane. It will then have twelve to eighteen hours over the Florida Straight, more than enough time to regain strength should any further EWRCs fail to materialize. It is worth noting that should the models shift even further west, additional time will be allotted to this hurricane to strengthen, if only a few hours, an effect that would likely be offset by increased land interaction.

Even a category three landfall will have devastating effects across southern Florida. Hurricanes Katrina, Rita, and Wilma were category three storms at their time of landfall. Category four strikes include Hugo, Charley, and Ivan. For an example of category five effects, look at Andrew, or even Irma’s own effects in the Lesser Antilles.

Make no mistake, this storm will have an extreme effect, no matter if it landfalls as a three, a four, or a five. Irma’s size has increased drastically over the past two days, and nearly all of the Florida Peninsula can be expected to experience hurricane force gusts at a minimum.

Impact
Hurricanes have many different impacts, all deadly and heavily damaging, including heavy rain, storm surge flooding, high winds, conventional severe weather, and overall infrastructural damage. Below are summaries for three different zones. Note that these zones can change at any time before and during the event, and this should NOT be used as an evacuation guide.

EXTREME IMPACT
Sustained winds of 100-130mph, with higher gusts.
Heavy coastal flooding from storm surge, especially on the western coast. Flooding may be accentuated by heavy waves.
Rainfall totals of ten or more inches, with hourly rates of one to two inches or higher possible during the peak of the storm.
Flash flooding and street flooding is possible to likely, especially in places with poor drainage, as well as low-lying areas and known flood zones.
Widespread, extended power outages are all but inevitable.
Many areas will be impassable for days or even weeks, especially closer to the coast. Some areas may become uninhabitable for an extended period of times.

SEVERE IMPACT
Sustained winds of 70-100mph, with higher gusts, especially in the southern and eastern portions of the zone.
Significant coastal surge flooding, especially on the western coast. Flooding may be accentuated by heavy waves.
Rainfall totals of six or more inches, with hourly rates of one to two inches or higher possible during the peak of the storm.
Flash flooding and street flooding is possible, especially in places with poor drainage, as well as low-lying areas and known flood zones.
Widespread power outages are likely, and power may remain out for an extended period of time.
Many areas will be impassable for days due to debris, standing water, etc.

SIGNIFICANT IMPACT
Sustained winds of 40-70mph, with higher gusts possible, especially of Irma retains her strength further inland than expected.
Moderate coastal surge flooding is possible in coastal areas, along with heavy wave action.
Rainfall totals of six or more inches, with hourly rates of one to two inches or higher possible during the peak of the storm.
Flash flooding and street flooding is possible, especially in places with poor drainage, as well as low-lying areas and known flood zones.
Scattered to widespread power outages are possible, and power may remain out for several days.


Notes
Emergency response will be hindered, if not rendered impossible, both during and after the event throughout much of eastern and southern Florida. If you haven’t evacuated and want to do so, the time is NOW! Every hour, this storm moves closer to landfall.
Focusing on an exact track is pointless; the swath of hurricane force winds is well over a hundred miles wide, and the swath of tropical storm force winds is triple that. No matter where Irma makes landfall, most of the state will see significant to major effects.
Should Irma make landfall as a category five, the wind and infrastructural impacts in the “EXTREME” zone may be higher than stated above. At this point, residents of southern and southeastern Florida should expect a crippling strike.
This storm is an imminent threat to life. Get out, or get safe.

Can't figure out how to upload an image...imageshack is no longer free.

I wonder if Irma is going onshore of Cuba and struggles to get off the coast for 12-20 hrs. this could possible take her down to Cat 2 or weaker. Hopefully not to recover. Weaker storms tend to move more westerly as well. Possible good news for Miami, not so good for Cuba. Prayers for all involved.

Very quickly tuning in. Is that an NHC forecast for a possible landfall at about 165mph?

[NDG]

To make things worst, pressure gradient will make winds worst well ahead of Irma thanks to that 1024 mb surface high over the TN valley.

[Kenderkin17]

It may not be relevant immediately, but can we for a moment look at the similarities between Jose and Irma. Other than their similar rapid intensification and utter strength, are the storms following the same trends / track? Will this, with these storms being so similar, help to promote the science of the models due to how close they are together?

** Not a pro met by any means, just a curious weather nerd.**

[JtSmarts]

I'm interested in seeing the HWRF simulated IR for 12z. I remember being spot on with storms in the past especially Arthur 2014.

[Langinbang187]

Dr. M seems to find it unlikely Irma will ever regain Cat 5 intensity. He mentions it could even potentially weaken to a 3 from interaction with Cuba. At least a bit of good news there, as he was expecting Irma to ramp back up to 185 MPH Yesterday.

[terstorm1012]

Ouch!
CAPE building up to 4000 in the Keys

this is one of my big concerns!