ATL: IRMA - Models

[sma10]

Amazing how subtle this stuff is. Why was the 00Z GFS so in line with the Euro, but the 06Z GFS much further north and a threat only to Bermuda? The cutoff trough in the 6Z run was a touch closer to Irma, only by a tiny bit, but enough to affect her track ever so slightly further North.

The 0Z GFS and 0Z Euro had the trough moving west ahead of Irma, maintaining a bit of distance; the 6z GFS had it moving southwest, a subtle enough difference to affect the entire endgame.

The little bugger currently near 25N 50W, may hold all the cards.

[WeatherEmperor]

The NAO forecast has more little red lines in positive territory indicating the NAO is more likely to be positive as we head into the first week of September.


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[ConvergenceZone]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

[AutoPenalti]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

In what way is the general trend a recurve? At the moment, all I see is a due west and then WSW track for the next couple of days and after that some hook it back west.

If you're comparing this based on climo then it's kind of wrong already because most models have it moving WSW after the first 4 days then on a due west to WNW track for the last 2.

CMC has been consistent though with ensembles hitting Bahamas and then Florida, but too early to tell.

If anything, I'd say 45% chance of recurve, 55% of a hit somewhere.

[Frank2]

Most storms that develop at 15N recurve - right now the models are split, but I'd bet it will recurve. Very few start that far north and don't...

Frank

[ConvergenceZone]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

In what way is the general trend a recurve? At the moment, all I see is a due west and then WSW track for the next couple of days and after that some hook it back west.

If you're comparing this based on climo then it's kind of wrong already because most models have it moving WSW after the first 4 days then on a due west to WNW track for the last 2.

CMC has been consistent with ensembles hitting Bahamas and then Florida.

What I mean is that yesterday, the models were depicting this continuing Westward towards the US mainland, and one of them showed it even hitting the Eastern Gulf. But today, not so much? but yes the CMC is the exception

[hurricaneCW]

Most storms that develop at 15N recurve - right now the models are split, but I'd bet it will recurve. Very few start that far north and don't...

Frank

I hope that's true, the last thing we need is another major hurricane on our tail.

[txwatcher91]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

As it stands right now the trend is definitely not for a recurve. You have the Euro and CMC ensembles both showing a threat to the US and areas like PR/Antilles. The Euro itself has a powerful storm heading for the Bahamas and takes it through the Herbert Box, as do the Euro ensembles. If it goes through that then not only would it probably impact the islands but increase the chance for a Bahamas/US impact. The GFS and it's ensembles are really the only ones showing a recurve and it has performed the worst of models this year. Climo suggests a storm going through the Herbert Box will impact land; along with the Euro/CMC ensembles and you have a pretty good agreement for potential landfall.

[blp]

Even though the 06z operational run of GFS was very different than the 00z. The ensembles are primarily still in line with the 00z so it could have been outlier run.

[Scorpion]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

Wow, so the 06z GFS recurves and now that is the general trend?

[SouthFLTropics]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

Wow, so the 06z GFS recurves and now that is the general trend?

It started with the 00z GFS last night which had it further east than yesterday's 18z. I've watched these models too much over the years to get excited about swings in the 7 to 10 day range. As always they will swing right and then left with the windshield wiper effect, until it locks in on a solution. Before this is all said and done I guarantee the GFS will swing back to a hit on Hispaniola and a slide into the GOM and then a few runs later it will be back towards Bermuda. Usually the answer lies somewhere in between which is why my early bet is on a close call for Florida with a possible brush or direct impact on the Carolinas. This could end up very much like Floyd in 1999.

[Bocadude85]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

Wow, so the 06z GFS recurves and now that is the general trend?

It started with the 00z GFS last night which had it further east than yesterday's 18z. I've watched these models too much over the years to get excited about swings in the 7 to 10 day range. As always they will swing right and then left with the windshield wiper effect, until it locks in on a solution. Before this is all said and done I guarantee the GFS will swing back to a hit on Hispaniola and a slide into the GOM and then a few runs later it will be back towards Bermuda. Usually the answer lies somewhere in between which is why my early bet is on a close call for Florida with a possible brush or direct impact on the Carolinas. This could end up very much like Floyd in 1999.

What everyone should be taking note of is the ensembles. The Euro,GFS and CMC ensembles all have Irma in the Western Bahamas/Florida region in 10-12 days. It's pretty remarkable to me that all of the Global model ensemble members are in relatively same area.

[ConvergenceZone]

So glad that the general trend is to recurve. I'd probably give it about a 90% chance to recurve. But that 10% chance of not recurring is probably higher then most storms that form this far out in the Atlantic

Wow, so the 06z GFS recurves and now that is the general trend?

If the other models trend this way today, then yes. As they say, the trend is your friend

[SouthFLTropics]

Wow, so the 06z GFS recurves and now that is the general trend?

It started with the 00z GFS last night which had it further east than yesterday's 18z. I've watched these models too much over the years to get excited about swings in the 7 to 10 day range. As always they will swing right and then left with the windshield wiper effect, until it locks in on a solution. Before this is all said and done I guarantee the GFS will swing back to a hit on Hispaniola and a slide into the GOM and then a few runs later it will be back towards Bermuda. Usually the answer lies somewhere in between which is why my early bet is on a close call for Florida with a possible brush or direct impact on the Carolinas. This could end up very much like Floyd in 1999.

What everyone should be taking note of is the ensembles. The Euro,GFS and CMC ensembles all have Irma in the Western Bahamas/Florida region in 10-12 days. It's pretty remarkable to me that all of the Global model ensemble members are in relatively same area.

This is an excellent point Bocadude85...The Ensembles have been extremely consistent for that range.

[HurricaneEric]

At this point, I will just refer to the forecast cone. It'll show the more likely track in the medium-range, which is what will most likely happen.

People should refrain from expecting or putting odds on this storm beyond what the cone shows. All we can say for sure right now is Irma will gradually intensify, going on a WNW to NW heading before making some sort of WSW to SW dip/dive. This should be a concern, as of right now, for the northern Lesser Antilles, Puerto Rico, and possibly the Bahamas. We'll see who else needs to monitor closely beyond that.

But again, I hope people can refrain from absolute certainties just based off climatology (or anything else for that matter). There are so many factors and technically this storm will already be going against climatology if this WSW/SW movement verifies. Lots of moving parts that will get ironed out in the coming days. This is what makes it so interesting!

[SouthFLTropics]

Here we go...12z GFS initiated

[SouthFLTropics]

A little further SW than 06z

[Siker]

GFS was 2mb off in its 6hr forecast from 6z. Now down to 1003mb at 18 hours vs. 1007mb on the 6z.

[forecasterjack]

ECMWF continues to consistently throw down a monster near the Bahamas D10: https://weather.us/model-charts/euro/72 ... 0000z.html other parameters via menus

Will this link still display the 00z run when the 12z is out in a few hours? Would be great to have some of these ECMWF HRES maps saved for future reference

Sorry for the late reply, indeed when 12Z data populates 0Z will disappear. However, I can post from the internal archives if you want to compare! Just let me know what parameters/times

[forecasterjack]

Also does anyone have the website that shows the individual member runs for the ECMWF ensembles? Someone posted it a week or two ago but lost the link.

https://weather.us/model-charts/euro can select each ensemble under "members" menu. Use other menus to adjust domain and parameters