ATL: KAREN - Models

[ronjon]

What moves it out is not a trough but just the Ridge moving positions. Amazing how quickly the ridge readjusts from 192-240hrs.

Actually I think its also the upper midwest trof that erodes the strength of the ridge and its orientation. But if we think its really going to take 10 days to reach the east US coast, as I said earlier, we can lay odds on an OTS scenario this time of year.

[ava_ati]

I think at this point there is so much consensus among the models, Karen is coming west... How strong and where exactly are what we will be ironing out over the next week and a half.

[Miami Storm Tracker]

With the way that 12 Z run looks the high appears to be strong it may continue WSW to the straits or even Cuba.

[LarryWx]

LarryWX how them EPS lookin'?

12z EPS preliminary of TC's hitting CONUS with SLP of 1003 mb or lower: still a threat with 7 total hitting members out of 51 or 14% vs 16%/8 of the 0Z I don't see any member stalling as a TC just off FL like on the operational

1. 10/1 FL Keys weak TD?
2. 10/1 Just N of WPB TS?
3. 10/3 Just N of WPB TS?
4. 10/3 St. Aug. H
5. 10/4 SE tip FL H
6. 10/4 Cape Canaveral TS?
7. 10/7 FL Keys/far S tip H

[Jr0d]

https://i.imgur.com/rcL0exm.png

All are moving Karen slowly after the west turn. How fast Karen moves after making the turn is going to be crucial.

It initially looked like strong riffing would possibly push Karen quickly west or wsw, however it seemed like that is no longer the case.

Does anyone have an idea why the have slowed Karen down significantly?

[kevin]

ECMWF ensemble 12z

6/51 US landfall = 12% (TS to Cat 1 - strongest member 90mph)
1/51 Cuba landfall = 2% (TD)
Approximately half of the members make the clear turn West

[Frank2]

Irma first made landfall in the Keys as a Cat 4. If I remember correctly, it had weakened to a Cat 3 after interaction with Cuba and then intensified again prior to Big Pine Key/Cudjoe area.

I was referring to mainland Florida landfall but you are correct, though it eeked out a Cat 4 staus by 1 mph, and it began to become extra tropical wth the worst weather to the north of the center. Once the eye passed 50 miles to our west the weather steadily improved during the evening.

[toad strangler]

Karen is large.

[Weatherboy1]

I think the most important thing to be gleaned from all the modeling today is that a sharp turn to the left/west is likely. Many models show some version of it. Two most important questions are: 1) how far east of due north does Karen go in the next couple of days and 2) once she turns, how fast does she head west? The answer to the first is very important because if the starting point of her turn is 60W vs. 64W I doubt she'll get anywhere close to FL. The answer to the second is important because there's only so much ocean between the starting point and the Bahamas/Florida. A slower motion west like the GFS shows likely results in a recurve. A faster motion like the Euro makes the chance of a U.S. hit stronger.

Final point worth making? Any turn/stall is likely at least three days out and any potential landfall is more than a week out (excluding Puerto Rico, obviously). Sooooo lots of things can change that far out with modeling/overall environment!

[chris_fit]

It's gonna be interesting that's for sure...

[StruThiO]

how many TCs poleward of 25N and E of 65W have been steered into the US this time of year or later?

[rbaker55]

I think the most important thing to be gleaned from all the modeling today is that a sharp turn to the left/west is likely. Many models show some version of it. Two most important questions are: 1) how far east of due north does Karen go in the next couple of days and 2) once she turns, how fast does she head west? The answer to the first is very important because if the starting point of her turn is 60W vs. 64W I doubt she'll get anywhere close to FL. The answer to the second is important because there's only so much ocean between the starting point and the Bahamas/Florida. A slower motion west like the GFS shows likely results in a recurve. A faster motion like the Euro makes the chance of a U.S. hit stronger.

Final point worth making? Any turn/stall is likely at least three days out and any potential landfall is more than a week out (excluding Puerto Rico, obviously). Sooooo lots of things can change that far out with modeling/overall environment!

I tend to agree with this in the most part. The further west the turn happens the closer the threat. If the system slows its getting close to October, where fronts and troughs play even more important roles in turning TC's. Climatology wise, we are getting into the season in another week where GOM and Western Caribbean is open for business, where we have less time to watch and if a storm makes it into the GOM, it has to hit somewhere.

[Frank2]

how many TCs poleward of 25N and E of 65W have been steered into the US this time of year or later?

Not many and if only 12% call for a US landfall, I wouldn't bet a week's pay on that happening, because it means an 88% chance it won't...

P.S. GFS now showing a strong CF through FL by hour 240, so the pattern is very active and does not favor landfall - landfalling CV hurricanes are usually a Mid-July to Mid-September event...

[sma10]

I think the most important thing to be gleaned from all the modeling today is that a sharp turn to the left/west is likely. Many models show some version of it. Two most important questions are: 1) how far east of due north does Karen go in the next couple of days and 2) once she turns, how fast does she head west? The answer to the first is very important because if the starting point of her turn is 60W vs. 64W I doubt she'll get anywhere close to FL. The answer to the second is important because there's only so much ocean between the starting point and the Bahamas/Florida. A slower motion west like the GFS shows likely results in a recurve. A faster motion like the Euro makes the chance of a U.S. hit stronger.

Final point worth making? Any turn/stall is likely at least three days out and any potential landfall is more than a week out (excluding Puerto Rico, obviously). Sooooo lots of things can change that far out with modeling/overall environment!

All good points.
I'll just add that orientation and strength of ridge will be very hard to model perfectly at this time, and even though 65W to 80W is a relatively long way (and can feel like an eternity when tracking a slow moving TC), a due westward bowling ball of a system under the properly structured ridge can cover that ground in 2, 2.5 days, easy.

[Ubuntwo]

how many TCs poleward of 25N and E of 65W have been steered into the US this time of year or later?

Not many and if only 12% call for a US landfall, I wouldn't bet a week's pay on that happening, because it means an 88% chance it won't...

P.S. GFS now showing a strong CF through FL by hour 240, so the pattern is very active and does not favor landfall - landfalling CV hurricanes are usually a Mid-July to Mid-September event...

Thing is, it’s not like 88% of the ensemble members have it OTS. No, most have it turning west. The majority just have it too weak or dissipate it thereafter.

[kevin]

All 29 TC's in September to pass through the current position of Karen within 75 miles. None of them show real Karen-like behavior of nearly only North movement over Puerto Rico (at least if the models verify). The only one that looks kinda similar is Jeanne (and perhaps Gabrielle), which made the turn North after the Dominican Republic and hit Florida as a cat 3.

[SFLcane]

 https://twitter.com/shawnmilrad/status/1176583617327317009

[sma10]

how many TCs poleward of 25N and E of 65W have been steered into the US this time of year or later?

Not many and if only 12% call for a US landfall, I wouldn't bet a week's pay on that happening, because it means an 88% chance it won't...

P.S. GFS now showing a strong CF through FL by hour 240, so the pattern is very active and does not favor landfall - landfalling CV hurricanes are usually a Mid-July to Mid-September event...

Thing is, it’s not like 88% of the ensemble members have it OTS. No, most have it turning west. The majority just have it too weak or dissipate it thereafter.

For the record, I think you'll find that 12% chance of a Florida landfall 8 days out, is a very, very significant chance indeed.

[fci]

What moves it out is not a trough but just the Ridge moving positions. Amazing how quickly the ridge readjusts from 192-240hrs.

Actually I think its also the upper midwest trof that erodes the strength of the ridge and its orientation. But if we think its really going to take 10 days to reach the east US coast, as I said earlier, we can lay odds on an OTS scenario this time of year.

For sure. The TRUE exception would be a climatological-defying westward movement to FL from so far out at the beginning of October.
But we didn’t expect Ike to turn SW through Cuba or Irma to hug the North coast of Cuba or (MANY years ago) Betsy to get as far north as 29.0 before looping back and hitting Key Largo.
But....OTS is the obvious solution here but, with weird conditions and climate change effect; one never knows...

[CreponChris]

00 Zulu EPS for ya.



And here's yer 06 as well. G



ave you guys a 100 milisecond delay between frames as otherwise it's too fast, really. Interesting to see the NHC official track even showing that 90 degree or so turn in about 4 days or so. I never really saw what others seemed to be seeing on yesterday's GFS in terms of the two storms merging. Jerry and Karen, I mean. I saw Jerry weakening and then sending convection somehow back toward Florida. They seem too far apart to be able to 'merge' effectively, but I'm far from an expert. Keep up the good work. ~C Norman Crepon