ATL: DORIAN - Models

[hohnywx]

Anyone have the 12z Euro Ens to post?

[catskillfire51]

Anyone have the 12z Euro Ens to post?

https://www.weathernerds.org/tc_guidanc ... ?tcid=AL05

Still shows 00z but thats the site to use

[Aric Dunn]

12z eps.. more north but some stronger ones still South Florida and central florida.. alot of uncertainty still .... dont let you guard down.. the turn is far too close to the florida coast even a few hours longer motion before stalling will bring it too the coast.

[SouthFLTropics]

Aric,

How does the 12z EPS compare to the 06z EPS?

[Palmcitycane]

As you might remember I thought there was a slim change this could miss the coast, or recurve and graze the carolinas. I'm still not confident though because I don't like the coincidence that the models started showing recurve as we lost the extras upper air data due to equipment issues. I'll feel a lot better once that gets back into the modeling.

It's always a bad idea to declare someone in the clear. We go through this silliness every year, some posters seem to get a thrill declaring someone in the clear. It's fine to discuss why you think the storm is going where you think it's going, backed up with data.

The majority of posters here, including me, have no authority to declare anything. These types of posts will be removed and we may issue warnings or suspensions depending on the situation. Please just avoid it.

Here's the latest error chart

https://i.imgur.com/QGl1jJi.png

and here's the bias chart for 12, 24, and 48 hour forecast points.

https://i.imgur.com/vy4bu68.png

source: http://www.atmos.albany.edu/facstaff/tang/tcguidance/al052019/

Thanks for posting these Mark. The error and bias chart is helpful.

I'm try to understand the bias chart, almost all are bottom left from center. Does that mean that forecast model is forecasting each point southwest of the actual position of the storm?

[NDG]

Latest 12z Euro ensembles gives support to the latest NHC's forecast track of Dorian staying offshore.
If memory serves me correct 15 ensembles on its earlier 06z run showed a FL landfall, that number has now come down to 5 or maybe 6 at the most.

[Craters]

I just posted this in the Discussion group, but it can probably go here, too (I hope ).

If you want a very nice, little utility that will convert knots to mph or mph to kph or just about anything in between, try this:

https://joshmadison.com/convert-for-windows/

It's free, it does much more than speeds (pressure, time, volume, etc.), and I've been using it for years for all sorts of conversions. Keep a shortcut on your desktop and it's always right there. It's extremely easy to use and very self-explanatory.

[tolakram]

Thanks for posting these Mark. The error and bias chart is helpful.

I'm try to understand the bias chart, almost all are bottom left from center. Does that mean that forecast model is forecasting each point southwest of the actual position of the storm?

That's my assumption but I honestly don't know.

[Mouton]

FWIW, buoy reports to the NW and N of Dorian's path have begun to fall slowly over the past few hours. Not precipitously but down from what had been a rise to steady readings since all day to that point. They are removed enough to not be affected by Dorian so my theory is the ridge may be withdrawing slowly. Of course, it could also be daytime heating lowing pressure but I think I will stick with my thought anyway. I am a tad concerned that most of the models movement till recently have not been guided by actual readings as our planes have been grounded. I hope the ridge is indeed retreating.

Here is a question I have wrestled with for a long time. Does the GS current affect storms passing over head as is there any transmission of motion to the air mass from the water?

[SouthFLTropics]

FWIW, buoy reports to the NW and N of Dorian's path have begun to fall slowly over the past few hours. Not precipitously but down from what had been a rise to steady readings since all day to that point. They are removed enough to not be affected by Dorian so my theory is the ridge may be withdrawing slowly. Of course, it could also be daytime heating lowing pressure but I think I will stick with my thought anyway. I am a tad concerned that most of the models movement till recently have not been guided by actual readings as our planes have been grounded. I hope the ridge is indeed retreating.

Here is a question I have wrestled with for a long time. Does the GS current affect storms passing over head as is there any transmission of motion to the air mass from the water?

I do believe there is an effect on the track of storms by the Gulf Stream. Whether or not the models are able to pick up on that or not is questionable. My guess would be that they don’t.

[jasons2k]

and the St Mary's river and intercoastal in Nassau County. The Fernandina Beach marina is still under repair from Mathew. The bend at the Fl/Ga coast where the St Mary's/Amelia River outflow is a massive surge collector. Nowhere for the water to go especially during abnormally high "king" tides as the mouth is oriented toward NE winds.

Any idea what conditions would have to be met before they evacuate the island? Is it the strength of the storm or how far west it will be or a combination of both?

Technically almost the entire island is a cat 1 evac zone. The powers that be tend to discount that a bit if the storm is approaching from the SW as surge will be minimal. Storms up the coast or worse like Dora in 64 which came straight into Ponte Vedra are another matter. Mathew was a mandatory evac, few heeded it and had almost zero problem as it jogged east before land fall. Had it jogged west, not so good. The problem if you don't leave is they close the bridge and keep it closed till it is deemed safe on the island for return as in power lines removed from roads and major roads cleared of debris and if the bridge is deemed safe for crossing. We came back to some tree damage on our property but no structural and power off for a short while. Unless the NHC track moves further east, off of 80W, we are planning on leaving on Monday FWIW. Will put up shutters tomorrow and remove all loose stuff from the yard just in case. I'd rather have a short vacation away than sitting here in the dark with no AC! FWIW, the hurricane center shows a 23% chance of Mayport, just to our south, having cat 1 winds. That is interesting is it is the highest percent of all on the east coast at this time.

Another reminder that this thread is for model discussion. Please discuss surge and wind concerns in the discussion thread where it belongs - thanks!

[USTropics]

12z UKMET ensembles:

[Aric Dunn]

12z UKMET ensembles:
https://i.imgur.com/22PtaeH.png

Pretty amazing the operational is literally the farthest right of its members.. the average continue to be mostly through the middle of the state..

[MrJames]

12z UKM close up

[AtlanticWind]

12z UKM close up

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

This a little surprising, and disturbing

[PandaCitrus]

The majority of the ukmet ensembles come on shore of Florida. Everyone better hope this is incorrect because there is a serious lack of concern right now on the Florida coast of a hit. If Dorian is sneaky and stalls over South Florida instead of the Bahamas, a track well within the realm of possibility, that's a serious safety issue. South Florida is currently out of the cone and people are tuning out and the time for evacuations is short. A forecast bust could have life or death implications.

[floridasun78]

12z UKM close up

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

how old is ukmet this runs?

[sma10]

12z UKMET ensembles:
https://i.imgur.com/22PtaeH.png

This is mildly disturbing

[AutoPenalti]

UKMET continues to be east of the ensemble. Yikes.

[toad strangler]

UKMET continues to be east of the ensemble. Yikes.

Left bias though usually, correct?