ATL: ISAAC - Models

['CaneFreak]

It's inability to resolve the lowest pressure has NOTHING to do with the intensity forecast...no one uses the gfs for intensity anyways...it is only a global model

I would ignore the intensity in this run I don't see anyway it could get that strong (especially considering the GFS' inability to accurately resolve intensity).

Just my opinion, use the NHC/NWS for all weather-related decisions.

[Meteorcane]

I would ignore the intensity in this run I don't see anyway it could get that strong (especially considering the GFS' inability to accurately resolve intensity).

Just my opinion, use the NHC/NWS for all weather-related decisions.

Could you explain why you don't think it would get that strong? It seems quite a few models show it getting pretty strong now.

Conditions in the GULF are at least marginally conductive for development (An upper level AC to ventilate the system, most of the drier air concentrated in the Western Gulf, moderate heat content), however this storm has not at any point in its development shown the ability to organize at a rapid rate. That could change (there are many storms in history that have struggled throughout their lifetime and then blew up at some point ie.Katrina) however, this storm just does not seem to have the internal structure to take full advantage of its envirnoment.

[Jevo]

18z GFS+ 114

[PTPatrick]

This this still sitting At 114 hours...flooding east of center would be horrendous. My folks house would be in surge/fresh flooding from Tuesday afternoon through Wednesday night

[BigB0882]

18z GFS is about 6 hours faster to landfall....instead of Tuesday night, could be Tuesday afternoon

That is frightening because it would mean we are within 3 days of landfall and it gets harder and harder to argue with some of these models within 3 days. Of course, the models I am thinking of aren't exactly agreeing on a landfall (not that they are hundreds of miles apart) so the argument may continue...lol

[Blinhart]

So if more and more models other than the 18z GFS shows a more West solution, do you guys think the cone will finally start moving West. This is actually a very important thing, because the further West he goes the more likely there will be overwash of the levees of Lake Pontchartrain from the influx of the winds from the East and North. Do most of the people on here forget that Katrina actually didn't make landfall in New Orleans but more like Pass Christian, Ms. So these slight adjustments to the West have a huge effect on what will be happening in New Orleans. I'm not really worried about where I live, but for those that live in New Orleans and the areas around New Orleans. and the bay areas in between New Orleans and Pensacola.

[Shawee]

I'd be just as nervous in New Orleans as I would be in PC or here in Mobile. No telling where he goes between those points. The models seem to be doing a good job, but there's a huge difference in what 50 miles can get you. Just hope I'm on the "good" side or no side at this point.

We have that (nervous) covered. Still curious if/when the NHC will adjust the advisory to reflect the latest model runs. I'm not saying the K-word, but it was about this far out that the big advisory move was made, from about the same area. Again... not comparing this one to that one, or predicting a major shift, just comparing timing and wondering the same thing everyone else is.

[BigB0882]

I just wish the Euro and GFS would agree on a landfall for 3 runs in a row so we can all start the fun of wobble watching instead of spending so many times seeing which model shifts where.

[PTrackerLA]

I'd be just as nervous in New Orleans as I would be in PC or here in Mobile. No telling where he goes between those points. The models seem to be doing a good job, but there's a huge difference in what 50 miles can get you. Just hope I'm on the "good" side or no side at this point.

We have that (nervous) covered. Still curious if/when the NHC will adjust the advisory to reflect the latest model runs. I'm not saying the K-word, but it was about this far out that the big advisory move was made, from about the same area. Again... not comparing this one to that one, or predicting a major shift, just comparing timing and wondering the same thing everyone else is.

This just seems all too eerie, I remember that evolution of models/tracks like it was yesterday. Let's see what the 00z brings, once again...

[Frank P]

I would ignore the intensity in this run I don't see anyway it could get that strong (especially considering the GFS' inability to accurately resolve intensity).

Just my opinion, use the NHC/NWS for all weather-related decisions.

Remember what the NHC stated in its late update... conditions in Gulf per the models could be allow Isaac to be significantly stronger than forecast...

[BigB0882]

I think I said this earlier but one thing that worries me is that it FEELS like the GFS has been one step ahead of the Euro on Isaac from the very beginning. I am not saying that the Euro will go West into LA tonight but I can't really remember a time where the GFS was following the Euro with this. The GFS had its shifts and the Euro seems to follow a day or so later. Maybe my memory is completely warped from all the model watching but that's how it feels. Needless to say, I can't wait for the 0z tonight.

[BigB0882]

Did they collect any new data during the day that will be in the 0z runs tonight like they have the last 2 days? Dropsondes? The G-IV data or whatever it is called?

[Jevo]

Did they collect any new data during the day that will be in the 0z runs tonight like they have the last 2 days? Dropsondes? The G-IV data or whatever it is called?

The G-IV was up today.. Data will most likely be in 0z

[thetruesms]

Missed Earlier 12z WRF +69:

Big Bend Landfall

[img]http://desmond.imageshack.us/Himg651/scaled.php?server=651&filename=mexicometwrf.gif&res=landing[img]

Want to note that "WRF" is not a singular model to be referred to as the GFS or the Euro. The WRF is a regional model that can be customized and implemented by anyone who wants to. I can immediately think of more than 10 independent WRF implementations, including my own organization, and that's just a tiny fraction of what's out there. Sometimes you're looking at the WRF and you may not even realize it (HWRF, well I guess that's a little obvious. But the NAM is also a WRF instance). It's important when posting a WRF run, that you mention where it's actually coming from. In this case, it is from the Mexican version of the National Weather Service.

Why would you say the ensembles don't really count? From what I understand they do. If you look at all the models, the majority of the models are west of where the NHC puts it. So I'm just confused.

Bear in mind that ensembles are not meant to be thought of as independent model runs. Every member of the GFS ensemble is just another run of the GFS, at a lower resolution (for computational speed), with some conditions tweaked slightly. Rather than think of them as a bunch of model runs, it's really more to get an idea of how much variability is possible in the GFS. If you have a really tight envelope around the operational GFS, you can feel more confident that any errors in the initial conditions aren't having a strong impact. The wider it gets, the more small variations (which could be errors in the initial conditions) have an impact on the quality of the forecast.

[Portastorm]

Thank you for the great information and for clarifying!

[stormreader]

Very reasonable chance now that this thing will come right up the mouth of the Mississippi River or perhaps even just a tad west of that over the Grand Isle area in SE La (I would put my money there for landfalling eye.) Posted SE La earlier this afternoon with the first hints of these new runs. This is the period (72 hours pre landfall) when models really come into line. Isaac should maintain a steady heading (as forecast) just along the north Cuban Coast and into the Gulf. We had hints for the last several days (earlier runs of Euro) of a more westerly landfall, and now with the 72 hour timeframe upon us, we see this significant switch left. I think this is the real deal.

Don't know anything just an amateur!

[Frank P]

I've heard many people over the years say "The water in the Gulf is so warm...a hurricane can just explode!" when in reality it can't. It doesn't matter of SSTs are exceedingly warm or not. If the atmospheric conditions aren't right (and it lacks the structure) the storm simply cannot intensify to any great extent, to say nothing of RI. That being said, that *may not* be the case here.

Going along with NHC's estimation, a Cat 2 certainly isn't out of the realm of possibility here by any means. We've seen many storms get their act together in a hurry.

Also size of wind field play a hugh factor in surge heights..

Frank, great point a lot of folks (myself included) overlook. Camille was a 5; massive destruction, but not nearly as broad as the K/R sisters of 05. Not discounting anything with this one... or belittlinging the distruction that can be caused by even a "small" storm. We all have to keep our guards up and pray for the best with good preparations. hopefully the dry air to the west will keep in somewhat disorganized and the surge manageable for who ever gets this one.

Also remember Katrina was a slow mover, really piling up the water on the MS/LA/AL coasts... which only exacerbates the surge... hopefully this latest GFS run does NOT come to fruition...

[jhpigott]

18z GFS looks close to SO FL at hr 24

Yea. In the short term, 18z GFS appears to make a run at the upper Keys/extreme southern tip of the FL peninsula whereas last run it was closer to the lower keys.

[southerngale]

This is the models thread. Please take general discussions to the Discussion thread, please. We're having to move a lot of posts.

Also, for chat style conversation, visit the chatroom. You just might like it in there, too.

[ROCK]

hey look the 18Z GFS is further west... now we need the EURO to correct itself and we will be good to go...