NOLA Met " unprecedented swing in the computer models&q

[rtd2]

quote fron New orleans Met. (He's a great met IMHO!)

MAJOR SHIFT IN THE MODELS

SE LA THREAT INCREASING RAPIDLY

LANDFALL POSSIBLE ANYWHERE FROM SE LA TO W. FL PANHANDLE

BEGIN TO TAKE HURRICANE PRECAUTIONS TONIGHT AND TOMORROW

KATRINA LIKELY TO BECOME A MAJOR HURRICANE AS IT APPROACHES THE GULF COAST

HURRICANE WATCHES LIKELY TO BE ISSUED FOR US LATE SATURDAY

WARNINGS MAY FOLLOW FOR PARTS OF THE GULF COAST SUNDAY

Over the past 12-24 hours we have witnessed an unprecedented swing in the computer models. I don’t believe I have ever seen anything like this before. Model consensus is now clustered on south Mississippi for what could be a major category 4-5 hurricane. The official forecast track from NHC has just seen one of the most dramatic shifts I ever recall. They now bring Katrina into the Pascagoula/Biloxi area as a major category 4 storm. This is consistent with the consensus of the early 18Z model guidance I am looking at.

Now I usually don’t put much stock in one or two model runs swinging dramatically, but we are looking at overwhelming evidence this storm could come too close for comfort or perhaps closer. With NHC’s current track, the threat to Mobile and the MS coast would be highest, but there would still be a considerable threat to New Orleans if it stuck to that exact path.

Of course we know that it will most likely not stay on that path. In fact, there will be several adjustments. Most disturbing to me is that NHC’s forecast track is on the eastern side of the guidance envelope. This means the computers believe (for now) the storm will come further west. I highly suspect that in the next few model runs we will see the tendency for the models to shift back to the east a bit and I believe NHC is sensing this as well and that is why they have went on the eastern side of the model consensus which seems to be pointing more toward the mouth of the PEARL River.

Keep in mind, during Ivan we saw some model swings that came our way but nothing as dramatic and consistent as this.

What will be most critical to New Orleans will be the timing of the turn to the NW and eventually to the N. This storm is going to turn as a strong trough sweeps into the Midwest and erodes away the upper high that is over us now. The timing of this process is critical to the final forecast track and the models have decided to time this process slower, thus the westerly shift.

Please be advised the timing on this could change again and we could certainly see another shift in the models. Landfall will not occur until Monday, so there will be a lot of track changes between now and then.

I must also point out it is beyond the scope of the science to know where the exact landfall point will be this early. But it is becoming increasingly likely a major hurricane will plow into the Gulf coast somewhere between here and the western FL panhandle early next week. Intensity would be the big wildcard – and there is a lot of uncertainty about that. Any intrusion of dry air or other unseen factors could cause the storm to be weaker than expected. But the models are all pointing to a major hurricane.

So what should you do now? I would begin making plans and preparations for the possible arrival of a major storm at this point. There is no way to tell if we will see a direct impact as of now, but it can not hurt to be prepared.

Tomorrow may certainly bring more dramatic changes to the track, but I think the trends of the past 12 hours speak for themselves. This is not to say you should panic or get all worked up. Things change with the weather. But be smart, level-headed and calm.

New data is constantly coming in and I will be looking at it and will post as much as I possibly can. One thing is for certain – we will likely see more changes to the track. Whether or not is will be a change for the good or bad remains to be seen.

In the meantime I suggest you get away from your computer (the webmaster will kill me for this, but I am being honest), start thinking about what you may do to prepare, enjoy your Friday night as best you can, and start your preparations in earnest early tomorrow. According to NHC we have about 72 hours before this thing makes landfall, sometime early Monday afternoon. Let’s just hope it’s somewhere far from us.

John
_________________
John Gumm
Morning Meteorologist
WWL TV
1024 North Rampart Street
New Orleans, LA 70116

[cajungal]

Don't panic! Just keep an eye to the sky. And take action if neccessary.

[Ola]

new 18 utc GFS

[Florida_TSR]

The dramatic shift is due to the current motion. The NHC thought the storm would turn north much sooner. As I've said - the longer it takes to turn north the greater the risk spreads west. I believe the NHC is still too far east with the current track.

[LAwxrgal]

new 18 utc GFS

18z is similar to 12z. I'll wait until 0z to see what's up. I'm expecting another shift back right.

[hicksta]

Are you expecting. or just wanting?

[LAwxrgal]

Are you expecting. or just wanting?

Both. I'll admit it.

These models do have a tendency to flip-flop.

[btangy]

Flip flop maybe... but usually it occurs with one or two of the global models, but for all of them to shift significant westward is different. Also, there's better evidence this is a trend in the models.. If you look at the ensemble runs of the GFS, there's been an increasing number of the ensembles taking Katrina further W. The operational run is just reflecting the trend in the ensembles.

[btangy]

Remember: The Trend is Your Friend. This is most definitely a trend and not a flip flop:

[canegrl04]

Katrina could be one for the record keepers as far as track predictions go. I pray she won't hit as a cat 4.Especially New orleans