ATL: ISAIAS - Models

[HurricaneFrances04]

CMC strengthens it as it gets kicked OTS near the Bahamas.

[TheStormExpert]

Now watch the Euro go all out again on it’s 12z run as the others seem to be less enthusiastic on significant development.

[ConvergenceZone]

Looks like conditions may not be as favorable in the SW Atlantic as I previously thought for 92l...if 92l even makes it there:

https://i.postimg.cc/GphYddQv/gfs-shear-watl-21.png

Based off of one run? The problem this run is that it accelerates too fast into the dry air and becomes decoupled thus not allowing it to form a ULAC because it stays too weak.

Based also on yesterday’s JMA which showed weakening between hours 168 and 192 in the same general area.

And the only reason is because it's July. Had this been happening in late August, the conditions would be different and we would probably be looking at a cat 4/cat 5 hurricane....

[northjaxpro]

Based off of one run? The problem this run is that it accelerates too fast into the dry air and becomes decoupled thus not allowing it to form a ULAC because it stays too weak.

Based also on yesterday’s JMA which showed weakening between hours 168 and 192 in the same general area.

My point is that it's way too early to look at any of the intensity trends. Should've learned that from Gonzalo and Hanna but here you are using the models to predict and storm without an LLC out at 120 something hours. There is a reason the NHC doesn't do cones for invests. Please at least wait until we have a Depression to start doubting the Tropical cyclone.

Preach on!! You are so on point here NewEnglandWX. I could not have said this any better!

[HurricaneFrances04]

It doesn't look like many of the GFS ensembles show much weakening, although they don't really show a major hurricane either. All pretty much show a recurve, some further west than others. Classic EURO vs GFS battle

[HurricaneFrances04]

UKMET a smidge closer to Puerto Rico. Shows a strengthening storm. Side note, for some reason the UKMET ensembles haven't updated on Weather Nerds since the 00Z run yesterday for some reason.


NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 13.5N 47.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 28.07.2020 48 13.3N 50.0W 1008 33
0000UTC 29.07.2020 60 14.3N 52.6W 1006 38
1200UTC 29.07.2020 72 15.5N 56.3W 1003 43
0000UTC 30.07.2020 84 16.5N 59.3W 999 49
1200UTC 30.07.2020 96 17.7N 62.4W 993 53
0000UTC 31.07.2020 108 19.2N 65.3W 981 64
1200UTC 31.07.2020 120 20.7N 68.3W 975 64
0000UTC 01.08.2020 132 22.6N 71.0W 970 66
1200UTC 01.08.2020 144 24.9N 73.6W 963 74

[blp]

Looks like conditions may not be as favorable in the SW Atlantic as I previously thought for 92l...if 92l even makes it there:

[l]https://i.postimg.cc/GphYddQv/gfs-shear-watl-21.png[/url]

Just remember Dorian last year. When it was Invest 99l all the models had it barely surviving only to then change their tune and flourish in the Bahamas. We have seen this picture many times before. Once Dorian became classified and had an established position models got a better handle and things started to change. Shear forecast are garbage at this point.

Pending the Euro all we know is the models have not wavered on developing a system that may hit the Caribbean and Bahamas and make a close approach to the US.

[MississippiWx]

Just curious, but did any of you pay attention to basically every model missing out on a HURRICANE forming in the Gulf of Mexico this week-even as little as 1-2 days out?

So yeah...I’m sure these 5-6 day model outputs are solid. Until 92L can decide which vort is the dominant one, long range model output is useless.

[TheStormExpert]

UKMET a smidge closer to Puerto Rico. Shows a strengthening storm. Side note, for some reason the UKMET ensembles haven't updated on Weather Nerds since the 00Z run yesterday for some reason.


NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 13.5N 47.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 28.07.2020 48 13.3N 50.0W 1008 33
0000UTC 29.07.2020 60 14.3N 52.6W 1006 38
1200UTC 29.07.2020 72 15.5N 56.3W 1003 43
0000UTC 30.07.2020 84 16.5N 59.3W 999 49
1200UTC 30.07.2020 96 17.7N 62.4W 993 53
0000UTC 31.07.2020 108 19.2N 65.3W 981 64
1200UTC 31.07.2020 120 20.7N 68.3W 975 64
0000UTC 01.08.2020 132 22.6N 71.0W 970 66
1200UTC 01.08.2020 144 24.9N 73.6W 963 74

The 12z UKMET must be the only global model left (at least that I’ve seen) that actually develops 92L into a hurricane.

[TheStormExpert]

Just curious, but did any of you pay attention to basically every model missing out on a HURRICANE forming in the Gulf of Mexico this week-even as little as 1-2 days out?

So yeah...I’m sure these 5-6 day model outputs are solid. Until 92L can decide which vort is the dominant one, long range model output is useless.

The thing is they’re or were developing something significant from 92L only to back off on intensity due to unfavorable atmospheric conditions. I see your point but the atmosphere was more favorable in the Gulf for Hanna than what it likely is for 92L.

[Ubuntwo]

UKMET a smidge closer to Puerto Rico. Shows a strengthening storm. Side note, for some reason the UKMET ensembles haven't updated on Weather Nerds since the 00Z run yesterday for some reason.


NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 13.5N 47.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 28.07.2020 48 13.3N 50.0W 1008 33
0000UTC 29.07.2020 60 14.3N 52.6W 1006 38
1200UTC 29.07.2020 72 15.5N 56.3W 1003 43
0000UTC 30.07.2020 84 16.5N 59.3W 999 49
1200UTC 30.07.2020 96 17.7N 62.4W 993 53
0000UTC 31.07.2020 108 19.2N 65.3W 981 64
1200UTC 31.07.2020 120 20.7N 68.3W 975 64
0000UTC 01.08.2020 132 22.6N 71.0W 970 66
1200UTC 01.08.2020 144 24.9N 73.6W 963 74

The 12z UKMET must be the only global model left (at least that I’ve seen) that actually develops 92L into a hurricane.

12z ICON and CMC both make it a hurricane as it recurves.

[TheStormExpert]

Looks like conditions may not be as favorable in the SW Atlantic as I previously thought for 92l...if 92l even makes it there:

[l]https://i.postimg.cc/GphYddQv/gfs-shear-watl-21.png[/url]

Just remember Dorian last year. When it was Invest 99l all the models had it barely surviving only to then change their tune and flourish in the Bahamas. We have seen this picture many times before. Once Dorian became classified and had an established position models got a better handle and things started to change. Shear forecast are garbage at this point.

Pending the Euro all we know is the models have not wavered on developing a system that may hit the Caribbean and Bahamas and make a close approach to the US.

I think at this point most of us have amnesia of what happened in prior seasons with prior storms, especially with all that’s been going on this year.

[toad strangler]

Looks like conditions may not be as favorable in the SW Atlantic as I previously thought for 92l...if 92l even makes it there:

[l]https://i.postimg.cc/GphYddQv/gfs-shear-watl-21.png[/url]

Just remember Dorian last year. When it was Invest 99l all the models had it barely surviving only to then change their tune and flourish in the Bahamas. We have seen this picture many times before. Once Dorian became classified and had an established position models got a better handle and things started to change. Shear forecast are garbage at this point.

Pending the Euro all we know is the models have not wavered on developing a system that may hit the Caribbean and Bahamas and make a close approach to the US.

I think at this point most of us have amnesia of what happened in prior seasons with prior storms, especially with all that’s been going on this year.

You won't ever see me making definitive statements based off one or a few model runs. It makes for just poor understanding of modeling and what their usefulness is. Those doing that who end up being correct are just lucky and learn nothing

[TheStormExpert]

Just remember Dorian last year. When it was Invest 99l all the models had it barely surviving only to then change their tune and flourish in the Bahamas. We have seen this picture many times before. Once Dorian became classified and had an established position models got a better handle and things started to change. Shear forecast are garbage at this point.

Pending the Euro all we know is the models have not wavered on developing a system that may hit the Caribbean and Bahamas and make a close approach to the US.

I think at this point most of us have amnesia of what happened in prior seasons with prior storms, especially with all that’s been going on this year.

You won't ever see me making definitive statements based off one or a few model runs. It makes for just poor understanding of modeling and what their usefulness is. Those doing that who end up being correct are just lucky and learn nothing

Well I mean I remember Dorian and it’s effects but I vaguely remember it in its early stages and what models were doing prior to it’s development. Same goes with storms such as Irma, and Matthew.

[HurricaneFrances04]

[Aric Dunn]

I just really hope no one is actually taking any model seriously right now.. lol

before Hanna developed ...and every other system this year.. the globals showed almost no development. it was not until after it was an actual TD/TS that the models were finally force-fed data and then they still got intensity wrong.


Hanna was the worst I have seen a long time..

Global models just absolutely refused to acknowledge the surrounding environment and steering.. nothing until it had become a TS..


SO dont even think about taking any of these models right now seriously until it is a well established system.

[chaser1]

UKMET a smidge closer to Puerto Rico. Shows a strengthening storm. Side note, for some reason the UKMET ensembles haven't updated on Weather Nerds since the 00Z run yesterday for some reason.


NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 13.5N 47.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 28.07.2020 48 13.3N 50.0W 1008 33
0000UTC 29.07.2020 60 14.3N 52.6W 1006 38
1200UTC 29.07.2020 72 15.5N 56.3W 1003 43
0000UTC 30.07.2020 84 16.5N 59.3W 999 49
1200UTC 30.07.2020 96 17.7N 62.4W 993 53
0000UTC 31.07.2020 108 19.2N 65.3W 981 64
1200UTC 31.07.2020 120 20.7N 68.3W 975 64
0000UTC 01.08.2020 132 22.6N 71.0W 970 66
1200UTC 01.08.2020 144 24.9N 73.6W 963 74

The 12z UKMET must be the only global model left (at least that I’ve seen) that actually develops 92L into a hurricane.

12z ICON and CMC both make it a hurricane as it recurves.

Correct. 960's pressures for ICON, and 970's for CMC. Oh wait..... add the BADGEM oops, meant NAVGEM also bring this to a 960's hurricane. Seems like nearly every model brings this to a hurricane at some point.

[Cpv17]

I just really hope no one is actually taking any model seriously right now.. lol

before Hanna developed ...and every other system this year.. the globals showed almost no development. it was not until after it was an actual TD/TS that the models were finally force-fed data and then they still got intensity wrong.


Hanna was the worst I have seen a long time..

Global models just absolutely refused to acknowledge the surrounding environment and steering.. nothing until it had become a TS..


SO dont even think about taking any of these models right now seriously until it is a well established system.

100% agree!

[Nuno]

Yeah, I don't get this waiting on baited breath for each long range run. Models have been poor at cyclogenesis to begin with, and we know the wiper effect will be on. I'll wait until we have an established LLC.

[TheProfessor]

As always timing is the key. The first thing we need to figure out is where the center forms, until that happens just about anything is on the table. Second we need to see how quickly the trough in Canada is able to erode the ridge. This determines how far west the storm gets initially. The third thing to watch is where exactly the storm is at when that cutoff low occurs. If the storm is already on its way out then there's not much worry for the mainland U.S, however if the storm is a bit delayed(like on the 6z GFS Parallel) then the cutoff low could actually increase the chance of a U.S landfall. The reason is because on both GFS models it sort of works to amplify the ridge and if the storm gets trapped under the ridge then a U.S landfall becomes extremely likely.

There's a lot that needs to be worked out still, if 92L's southerly energy is the one that forms and it take a more southerly track through the Caribbean, we could see some weird things track wise if it isn't quite able to feel the weakness to the north to escape but enough of it to move north in the short term before it gets shunted to the west. Something like Matthew with a more westward bend could happen if it doesn't take the first escape route.