ATL: FLORENCE - Models

[Emmett_Brown]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

[txwatcher91]

Flo isn’t even at 60W, I’ve never seen such good model concensus over 1200 miles away... Wow!

Is it going to be this easy to predict?

Models usually handle steering under a strong high quite well especially when no troughs/critical timing of short waves is involved.

[Blinhart]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

So that is over 200 miles off closer to 250 miles.

[PTrackerLA]

[Emmett_Brown]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

For fun, I just did the same comparison with the Euro 0z 9/6 run. It had Flo at approx 26.0N, 58.4W at 0z 9/10 (now). This is a bit closer, but still 1.5 degrees too far N. So models appear to have had a right bias 4 days out.

[weathaguyry]

I just looked and it seems like some of the GFS ensembles had this riding up the coast and being an issue for the NE, is this a possibility that should be payed attention to, or is it just the GFS up to its doomsday tricks?

[smithtim]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

So that is over 200 miles off closer to 250 miles.

1 minute = 1 nautical mile, so 1 degree = 60nm or 3 degrees =180 which you're right is over 200 standard miles. That's pretty mich the difference of a state...

Hopefully we'll see the expected turn to NW soon and really be able to nail down exactly, but if not and she continues heading due west longer than expected will be very interesting to see what the models have to say about that tommorow?? Time will tell, as with every storm you just never really know until the storm decides what it's gonna do...

[reds37win]

not directly related to models but kinda is....this will probably produce a monster storm surge for coastal nc. The water was nearly on NC12 tonight on Ocracoke where the dunes are washed away. Higher than normal tide cycle right now. If this comes in at high tide, like it very well may, it will add another 2 feet or so to the surge, and I am not sure that surge models take king tides into consideration.

The longer it takes to come in and slower speed, the surge will be just building on top of itself and the Waves will be building constantly also. Not a very good set up, some of these barrier islands might be completely washed away, if they don't have the Concrete walls like Galveston has there is no way they will be able to rebuild because all the dirt and everything else will be washed away and to the main shore.

I can appreciate the fact that this will be a seriously strong storm, but let's not get carried away. The outer banks is not a series of sandbars - they are a series of barrier islands. Now, it's likely there will be extensive beach erosion and even a breach or three cannot be ruled out, but thinking the barrier islands will be washed away is just not going to happen.

[Aric Dunn]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

So that is over 200 miles off closer to 250 miles.

1 minute = 1 nautical mile, so 1 degree = 60nm or 3 degrees =180 which you're right is over 200 standard miles. That's pretty mich the difference of a state...

Hopefully we'll see the expected turn to NW soon and really be able to nail down exactly, but if not and she continues heading due west longer than expected will be very interesting to see what the models have to say about that tommorow?? Time will tell, as with every storm you just never really know until the storm decides what it's gonna do...

So far, I have been tracking anywhere from 24.3 to 24.6 with every convective burst. unfortunately, because of said convection, we do not know the true motion yet. however it is still likely 270 with a lot of wobbles.

[Emmett_Brown]

It is interesting that we have such good agreement this far away from the landfall point. Just for fun, I went back to a randomly chosen GFS run (I love TropicalTidbits, where would we be without this amazing tool).

The 0z 9/6 run of the GFS predicted that at 0z Monday 9/10 (as in now...) Florence would be near 27.8N, 57.3W. It got the longitude pretty close, but is pretty far off on the latitude... it was over 3 degrees too far N. So, it shows how far off it can be 4 days out.

For fun, I just did the same comparison with the Euro 0z 9/6 run. It had Flo at approx 26.0N, 58.4W at 0z 9/10 (now). This is a bit closer, but still 1.5 degrees too far N. So models appear to have had a right bias 4 days out.

To extend the comparison one step further, the NHC 03Z 9/6 advisory predicted that Flo would be located at: OUTLOOK VALID 10/0000Z 27.2N 58.1W. So they have had a right bias 4 days out as well. Don't misunderstand my post as saying it won't hit along the NHC forecasted path, they do a great job, but I think we should be aware so that we stay vigilant. That 4 day cone is big for a reason.

[hohnywx]

I just looked and it seems like some of the GFS ensembles had this riding up the coast and being an issue for the NE, is this a possibility that should be payed attention to, or is it just the GFS up to its doomsday tricks?

I mean, anything is possible, but virtually no other guidance is showing a path like the 18z GEFS mean, so I wouldn’t really give it much credence.

[tolakram]

18Z HWRF run save

[tolakram]

18Z GFS run

[Aric Dunn]

Here comes the wild west of MOdels.. drumm rollllll... GFS>>

[reds37win]

Many in NC will use Fran as a comparison for this storm. Looking through old articles, Fran was a Cat-3 hurricane with max sustained winds of 115 mph. Wake County (home to Raleigh) saw about 8 inches of rain. The forecast for Florence looks much worse in terms of both wind and rainfall amounts.

What made Fran especially bad was the soft soil as a result of heavy rainfall the week before landfall. The trees were ripe for a nice wind. There is a chance of T-storms before Flo arrives, but the ground will not be nearly as saturated as it was before Fran. I'm hoping this makes a big difference. The amount of rain is really going to be a concern and reminds of Floyd which resulted in 500 year flood levels.

It's going to be a tough week.

[tolakram]

[emeraldislenc]

The models do not look good for me here in Emerald Isle. We are hoping for the best.

[tolakram]

[tarheelprogrammer]

GFS slightly weaker with the ridge.

[tarheelprogrammer]

When does the UKMET come out?