ATL: FLORENCE - Models

[Vdogg]

Consensus track now appears to be Morehead City to Greenville to Rocky Mount as opposed to Wilmington to Fayetteville to Raleigh. That slight shift would take millions of people out of the RFQ.

The EPS/ECMWF had a notorious short-term W bias with Irma last year as that hurricane neared South FL and the Keys. I'm not surprised to see the E shifts in guidance. I'm not downplaying this storm, but I've always suspected the worst-case scenario(s) were improbable. This will still be a very serious event, but far less than it could have been, at least in my humble view.

This will be a horrible position for all the Carolina's and DelMarVa. There will be continous powerful winds with rain on top of it for days. This is a horrific situation, just because a system comes in 40 miles further North than one spot doesn't mean it will not be serious. You are talking about serious storm surge going up all the bays, including Chesapeake Bay.

Exactly. That shift is catastrophic for Norfolk/Va. Beach. It takes millions out of RFQ, to only put a different million in it.

[PandaCitrus]

A northern Norfolk/VA Hit with RFQ and then up Chesapeake Bay is the ultimate catastrophic scenario puts many, many millions and DC metro in harms way. There were model runs last week that hinted at this scenario.

[supercane4867]

[Ken711]

[im g]https://i.imgur.com/4E1iGyy.gif[/img]

Very close to Euro landfall location.

[Sciencerocks]

The gfs is truly a funny model.

I'd take its southern North Carolina final landfall inline with the ecmwf as where it is going to make landfall as it will likely be a straight "line" track into the Carolina's.

[hurricaneCW]

Even when the Gfs misses NC on the first try, it still manages to get them. That's what happens when you have nothing but ridges for thousands of miles out.

Gfs essentially loops her around the gulf stream and waits for the next ridge to build to her northeast and send her to the coast. We'd be talking days and days of pounding surf and erosion before the storm even makes LF.

[PandaCitrus]

GFS does a loop de loop stall to get to the same place as Euro. That says it all. CRAZYTOWN.

[Ken711]

A northern Norfolk/VA Hit with RFQ and then up Chesapeake Bay is the ultimate catastrophic scenario puts many, many millions and DC metro in harms way. There were model runs last week that hinted at this scenario.

I'd be surprised to see it move NE up the Chesapeake Bay.

[PandaCitrus]

Now moving NNE through eastern NC.

[PandaCitrus]

I'd be surprised to see it move NE up the Chesapeake Bay.

The models last week had some prolonged NNW runs that went straight to DC after hitting the outer banks. There weren't stalls or loop de loops. It was a parabolic northwest path.

[tallywx]

Even when the Gfs misses NC on the first try, it still manages to get them. That's what happens when you have nothing but ridges for thousands of miles out.

Gfs essentially loops her around the gulf stream and waits for the next ridge to build to her northeast and send her to the coast. We'd be talking days and days of pounding surf and erosion before the storm even makes LF.

That would be the Diana 1984 track and you'd have to expect serious core degradation due to upwelling and continental dry air intrusion during the loop.

[cheezyWXguy]

As ridiculous as this model run is, it's a little unnerving that it isn't the first time the gfs has shown this move, or this intensity. The intensity is obviously overblown, but it does suggest the possibility that Florence could be moving very slowly in an environment that would allow it to strengthen or at least maintain until landfall...wherever that is. I couldn't be further from taking this as gospel, but I can't help but acknowledge the possibility of some version of this occurring.

[Hypercane_Kyle]

FV3-GFS has a far better handle on Florence, 12z FV3-GFS close to the ECMWF/NHC.

[Emmett_Brown]

So, does this mess up the tight clustering and agreement we had yesterday? It appears the new ridge forecasted to build in is giving the GFS and it's new replacement the FV3 fits. The forecast is getting more difficult near landfall it would seem.

[Emmett_Brown]

FV3-GFS has a far better handle on Florence, 12z FV3-GFS close to the ECMWF/NHC.

Even the FV3 shows a terrible looping scenario just inland from the coast, so there is definitely some uncertainty being introduced by that new ridge.

[Ken711]

I'd be surprised to see it move NE up the Chesapeake Bay.

The models last week had some prolonged NNW runs that went straight to DC after hitting the outer banks. There weren't stalls or loop de loops. It was a parabolic northwest path.

Not what the NHC and models are showing presently though.

[meriland29]

Is it likely or possible this change in latitude now will cause her to hit a less populated bit or stay offshore and go out?

[tallywx]

FV3-GFS has a far better handle on Florence, 12z FV3-GFS close to the ECMWF/NHC.

Even the FV3 shows a terrible looping scenario just inland from the coast, so there is definitely some uncertainty being introduced by that new ridge.

The new ridge is concerning and could be the downstream sink of the upward motion now being introduced by the strengthening disturbance over the Carib/GOM. It builds in and blocks the storm from coming in initially, but then provides the shield and steering to loop it back in as opposed to OTS track. Of course one has to wonder what would be left of the system on such a track. Would convection get stripped away during the loop (Diana 1984), or could it maintain or build (Elena 1985)?

[meriland29]

FV3-GFS has a far better handle on Florence, 12z FV3-GFS close to the ECMWF/NHC.

Even the FV3 shows a terrible looping scenario just inland from the coast, so there is definitely some uncertainty being introduced by that new ridge.

The new ridge is concerning and could be the downstream sink of the upward motion now being introduced by the strengthening disturbance over the Carib/GOM. It builds in and blocks the storm from coming in initially, but then provides the shield and steering to loop it back in as opposed to OTS track. Of course one has to wonder what would be left of the system on such a track. Would convection get stripped away during the loop (Diana 1984), or could it maintain or build (Elena 1985)?

Forgive me, but what does 'downstream sink' mean? At least in this case? Would the trajectory take a more W or WSW motion?

[Blinhart]

Is it likely or possible this change in latitude now will cause her to hit a less populated bit or stay offshore and go out?

If it gets within 100 miles of the coast, it will be causing serious hazards all across the East Coast. This storm is probably already over 200 miles wide and growing, so this will have effects all the way up and down the East coast.