ATL: DORIAN - Models

[Jonny]

Which is more reliable ECMWF or UK?

[jfk08c]

Which is more reliable ECMWF or UK?

Really tough question as each model has their own biases. Euro is widely considered the best global model, however, UK has been doing pretty well as of late.

[Agua]

I think, as Aric previously alluded to, that much will depend on when that bend to the west happens. If it happens earlier than forecasted then things will get very interesting.

Things aren't interesting enough for ya now?

[stauglocal]

https://twitter.com/DTVaWeatherman/status/1167169829805133826

DT is a good met, his best statement on FaceBook:

"However given that it still late Summer and just turning into early Autumn it is quite possible that the weather models are overdoing the depth of this trough. They often do that in the extended range. If that is the case we should know in a subsequent weather models over the next 36 hours and we may see less of a turn to the northwest and increased chance of Dorian getting into the eastern Gulf of Mexico."

Yup, happens consistently at this time of year

Good point!!!

[caneman]

I posted this on the other thread.

To see how much the 12z Euro is an outlier, here's travel times for landfalls from today's 12z model suite. The average landfall time from the nine other models not named Euro is 100 hrs.

GFS - 99 hrs (Vero Beach)
GFS Legacy - 99 hrs (Jupiter)
CMC - 117 hrs (Jupiter)
NAVGEM - 108 hrs (WPB)
ICON - 108 hrs (Ft Laud)
HWRF - 96 hrs (Melbourne)
HMON - 102 hrs (Miami)
NAM - 84 hrs (WPB)
UKMET - 84 hrs (WPB)
Euro - 144 hrs (WPB)

That is really eye opening. We should track this over the next 24 hours model runs and see if the group moves towards euro or euro towards the group

This is misleading. Almost all of the models show some sort of stall or slowdown and some degree of a northern turn. The Euro is showing this slowdown further east rather than already over Florida thus the wider gap in time before landfall. The significant feature is the more eastern stall.

However, the Ukmet has been the most accurate inside of 96 hours. And they have landfall inside if 96 hours so it must be taken seriously

[USTropics]

Good news for tonight's 00z runs:

The National Weather Service has begun 6-hourly upper-air soundings
across portions of the mid-Atlantic and southeastern United States.
Six-hourly balloons are also being launched in Bermuda and Nassau in
the Bahamas. A NOAA G-IV synoptic surveillance mission is ongoing,
and the data from this flight will be assimilated into the 0000 UTC
model cycle.

[caneman]

Which is more reliable ECMWF or UK?

Really tough question as each model has their own biases. Euro is widely considered the best global model, however, UK has been doing pretty well as of late.

UKMET has been most accurate with Dorian inside of 96 hours

[ronjon]

And this from the 5 pm Disc:

A west-northwestward to westward motion should then continue into the weekend with Dorian
moving near or over the northwestern Bahamas and toward the Florida
peninsula. The guidance envelope has nudged southward this cycle,
with the ECMWF and HMON along the southern side, and the GFS
bracketing the northern side. There has also been an increase in
along-track spread or speed differences with day 5 positions among
the dynamical models ranging from near the northwestern Bahamas to
the northeastern Gulf of Mexico. This appears to be the result of
differences in the models' depiction of the strength or lack thereof
of the western portion of the ridge by day 5. The new NHC track
forecast is essentially unchanged through the first 2 to 3 days, but
has been adjusted southward and somewhat slower than the previous
advisory at 96 and 120 hours. Users are reminded to not focus on
the exact forecast track, as typical forecast errors at days 4 and 5
are around 155 and 205 miles, respectively.

[BensonTCwatcher]

Well the whole story of the Euro this run is leaning on no Florida landfall if you factor out the operational- the mean EPS and quite enough of the members keep this offshore or lessen the FL impacts. Feels like we're starting over here...

https://ruc.noaa.gov/hfip/tceps/2019/2019082912/esrl.eps.ecmb.hit.loop.05L.2019.2019082912.gif

[Hypercane_Kyle]

I do agree with the user (I'm sorry, I forgot who) who pointed out that hurricanes very rarely take that sharp of a turn so quickly. ECMWF shows Dorian almost doing a complete 180 from drifting WSW to going NNW in ~12 hours. That's breakneck for a hurricane. Usually the track looks up being more rounded and smooth looking.

[RL3AO]

A few posts deleted. This is a model thread. Not make a random post without data or logic thread.

[Aric Dunn]

So here is the deal.. image below shows the current Upper low placement VS the 12z initialized positions from the GFS and Euro.. both are quite far where it currently is. This has ramifications of course.

This is why the bend to the wnw is likely to start sooner and be more gradual rather than the sharper turn left as it rounds the top of the ULL. With the ULL farther away from dorian the turn will possibly be gradual.

Are there any signs of this ?

well yes .. notice the direction of the outflow pointing more WNW to nw ? well that is also the direction of the steering being imparted on Dorian by the ULL. IF the ULL was closer to Dorian the flow would be more out of the SSW right now.

in the image the red line the rough current track by both euro and GFS around the ULL position the models have it.

blue line is the direction steering from where the ULL is now.

if the blue line is taken then more ridging can build north of it which intern will keep in on a more westerly track longer ( UKMET and others).

As dorian Deepens this evening and overnight the upper low will have more of an influence and we may start seeing it staying on the left side of the forecast envelope.

Just something that needs to watched. the models have a good handle of the general setup but it seems there are discrepancies with the location and motion of some features.

[syfr]

Your blue line follows the aim of the NHC track pretty closely

[gatorcane]

18Z ICON slightly SW of 12Z at 75 hours near Grand Bahama

[EnnisTx]

A few posts deleted. This is a model thread. Not make a random post without data or logic thread.

So you're saying there are no models taking Dorian to or towards Texas?

[invest man]

Well the whole story of the Euro this run is leaning on no Florida landfall if you factor out the operational- the mean EPS and quite enough of the members keep this offshore or lessen the FL impacts. Feels like we're starting over here...

[url]https://ruc.noaa.gov/hfip/tceps/2019/2019082912/esrl.eps.ecmb.hit.loop.05L.2019.201908
2912.gif[/url]

NHC must not be considering the wsw dip. At least the cone map does not show the “dip”. Perhaps a less wsw dip would allow for a smoother n then nne track to eventually commence. Or perhaps it is a kind of blend of both euro and gfs models. Who knows throw a dart at a map! One thing for sure. All bets are off if it stalls of shore. And NOBODY needs a stall on shore!!! IM

[sma10]

18Z ICON slightly SW of 12Z at 75 hours near Grand Bahama

I'll say this - love it or hate it, the ICON definitely wins the award for persistence. I don't think it has wavered very much at all in the last 6-8 runs.

[beachman80]

I do agree with the user (I'm sorry, I forgot who) who pointed out that hurricanes very rarely take that sharp of a turn so quickly. ECMWF shows Dorian almost doing a complete 180 from drifting WSW to going NNW in ~12 hours. That's breakneck for a hurricane. Usually the track looks up being more rounded and smooth looking.

Irma did. She hit the brakes in Cuba and went north. It’s actually common when storms slow down they can change directions quickly. When they’re trucking they don’t usually change abrupt course.

[supercane4867]

[syfr]

I do agree with the user (I'm sorry, I forgot who) who pointed out that hurricanes very rarely take that sharp of a turn so quickly.

Agree.

Flo's left turn last year at the NC/SC line took the better part of 2.5 days to complete