ATL: FLORENCE - Models

[TheDreamTraveler]

FV3 GFS 00z landfall is similiar to euro and it also slowly moves inland up the mid atlantic.

[Steve]

168 weakening and in central VA. So forward motion slowed but the system isn’t that strong at that point. Weak TS or whatever.

https://www.tropicaltidbits.com/analysi ... 900&fh=168

[eastcoastFL]

Looks like there's a tiny bit more riding to the west at hour 96

Sadly, yes. This likely will not be going anywhere this run.

Could you post a pic or link?

[TheDreamTraveler]

The rainfall amounts are going to be something else with it stalling like that for days. The models have been showing it stalling and moving slowly for days.

[Steve]

The rainfall amounts are going to be something else with it stalling like that for days. The models have been showing it stalling and moving slowly for days.

Yeah the ridge is flatter but the system drops back into NC at 192. Equivalent of a loop or stall offshore but luckily inland even though the rain is gonna pile up. Hopefully it doesn’t stick around another day or two after this plot. Looked like it would lift out, but that hasn’t happened.

[Steve]

Looks like there's a tiny bit more riding to the west at hour 96

Sadly, yes. This likely will not be going anywhere this run.

Could you post a pic or link?

192
https://www.tropicaltidbits.com/analysi ... 900&fh=192

[Steve]

Heading back down to the coast around landfall point or a bit north at 216. So it’s roughly 95 hours of sticking around with the European.

[PTrackerLA]

Euro is showing over 30" of rain in Virginia...

[TheDreamTraveler]

Euro is showing over 30" of rain in Virginia...

Keep in mind too parts of Virginia have had one of their wettest summers on record...and then combine it with this. It'd be a disaster.

[Aric Dunn]

Alrighty, so just a quick look at everything. Still appears the models are being too quick with the turn. based on the placement of the ridging and the strength we will likely see Florence ( as usual) tracking left of each forecast point. this of course will lead to left shifts each model run do to the initialized position being off. eventually based on the later part of the model runs that yet another strong ridge builds in on the eastern seaboard( hence the stall) but by the time of the stall ( per the models) Florence is already to far north to be trapped. So what we need to watch is the motion of Florence over the next 36 hours... If it starts missing forecast points to the south then we will see sudden shifts in the models to the left.

Currently, Florence has been moving south of west ( per the last known center fix and my current center fix) down to near 24.2 to 24.4N area. The models will almost certainly shift more and given the surrounding environment a US landfall is highly likely. there are still a lot of ensemble members into north florida so we cant narrow down a landfall area. we go through this every year, and every time when a forecast is past 5 days showing ( in this case 2 run trend) the panic starts. 5 days is still borderline useful model output.

IN short. we need a little more data. Once the forecasted ridge builds in and we can sample it we will know. right now that ridge does not fully exist and we don't know the orientation or strength which leads to higher than the usual error in the models.

the 00z Euro has it beginning its turn 24 hours. that is when we must watch for deviations ... i.e continued westward motion beyond that time period. the models are sitting on a razors edge. the stall at the edge of the run is a clear sign that it wont take much for FLorence to get trapped under the next ridge as well.

so yeah.. we wait and hopefully everyone does not kill each other over every silly 5+ day model wabble

[Brent]

No good news on the euro ensembles still a lot to the left

[TheDreamTraveler]

Alrighty, so just a quick look at everything. Still appears the models are being too quick with the turn. based on the placement of the ridging and the strength we will likely see Florence ( as usual) tracking left of each forecast point. this of course will lead to left shifts each model run do to the initialized position being off. eventually based on the later part of the model runs that yet another strong ridge builds in on the eastern seaboard( hence the stall) but by the time of the stall ( per the models) Florence is already to far north to be trapped. So what we need to watch is the motion of Florence over the next 36 hours... If it starts missing forecast points to the south then we will see sudden shifts in the models to the left.

Currently, Florence has been moving south of west ( per the last known center fix and my current center fix) down to near 24.2 to 24.4N area. The models will almost certainly shift more and given the surrounding environment a US landfall is highly likely. there are still a lot of ensemble members into north florida so we cant narrow down a landfall area. we go through this every year, and every time when a forecast is past 5 days showing ( in this case 2 run trend) the panic starts. 5 days is still borderline useful model output.

IN short. we need a little more data. Once the forecasted ridge builds in and we can sample it we will know. right now that ridge does not fully exist and we don't know the orientation or strength which leads to higher than the usual error in the models.

the 00z Euro has it beginning its turn 24 hours. that is when we must watch for deviations ... i.e continued westward motion beyond that time period. the models are sitting on a razors edge. the stall at the edge of the run is a clear sign that it wont take much for FLorence to get trapped under the next ridge as well.

so yeah.. we wait and hopefully everyone does not kill each other over every silly 5+ day model wabble

Pretty much agree with everything you said. Also Michael Watkins put out a great tweet earlier showing how far east the gfs operational was and how much farther east it is than the others. Makes sense given how much more alike the FV3 GFS was to the euro.

 https://twitter.com/watkinstrack/status/1038684722975711233

[Brent]

if anything it looks like the Euro ensembles more favor SC

[Aric Dunn]

Alrighty, so just a quick look at everything. Still appears the models are being too quick with the turn. based on the placement of the ridging and the strength we will likely see Florence ( as usual) tracking left of each forecast point. this of course will lead to left shifts each model run do to the initialized position being off. eventually based on the later part of the model runs that yet another strong ridge builds in on the eastern seaboard( hence the stall) but by the time of the stall ( per the models) Florence is already to far north to be trapped. So what we need to watch is the motion of Florence over the next 36 hours... If it starts missing forecast points to the south then we will see sudden shifts in the models to the left.

Currently, Florence has been moving south of west ( per the last known center fix and my current center fix) down to near 24.2 to 24.4N area. The models will almost certainly shift more and given the surrounding environment a US landfall is highly likely. there are still a lot of ensemble members into north florida so we cant narrow down a landfall area. we go through this every year, and every time when a forecast is past 5 days showing ( in this case 2 run trend) the panic starts. 5 days is still borderline useful model output.

IN short. we need a little more data. Once the forecasted ridge builds in and we can sample it we will know. right now that ridge does not fully exist and we don't know the orientation or strength which leads to higher than the usual error in the models.

the 00z Euro has it beginning its turn 24 hours. that is when we must watch for deviations ... i.e continued westward motion beyond that time period. the models are sitting on a razors edge. the stall at the edge of the run is a clear sign that it wont take much for FLorence to get trapped under the next ridge as well.

so yeah.. we wait and hopefully everyone does not kill each other over every silly 5+ day model wabble

Pretty much agree with everything you said. Also Michael Watkins put out a great tweet earlier showing how far east the gfs operational was and how much farther east it is than the others. Makes sense given how much more alike the FV3 GFS was to the euro.

 https://twitter.com/watkinstrack/status/1038684722975711233

Yeah, there is still a lot of unknowns. all I can say is given the amount of ridging throughout the entire western atlantic and eastern US. it is very unlikely we see florence turn so early. especially when there such a strong building ridge. typically with such ridging you will see TC's move wsw or W and a good clip .. something is missing.. but regardless somewhere on the east coast likely going to take a hit from a cat 4.. or high cat 3..

[Aric Dunn]

I know its the NAM> but for what its worth. ridge is slightly stronger and farther west. also the track is about 150 south of the 00z..

[LarryWx]

The low SLP bias of the gfs above 25N for Hs continues to be a joke.

Any chance that bias could also explain the east bias to the tracks? I remember it being well east of Florida with Irma as well even three days out.

Yes, a good chance as that makes sense.

[KWT]

Interesting that the UKMO has flipped, it's usually the one that picks up ridge strength one of the best.

Still more agreement towards the Carolinas than not though.

HWRF has also backed off from it's cat-5 pressures and looks more reasonable based on location.

[bob rulz]

No good news on the euro ensembles still a lot to the left

Oof. Hardly any ensembles taking it out to sea.

[GCANE]

Insane

[KWT]

06z GFS is a little West and does make a direct landfall with pressure at 922mbs...but that is highly improbable in terms of pressure.

Also delays RI a touch as well which may account to slightly left of the 00z track.

NC/SC really do look like they are going to get Florence. .