CPAC: LANE - Post-Tropical

[gatorcane]

Looks like it's re-intensifying as per latest satellite imagery.

Lane has been defying shear forecasts once he passed 150W

https://images2.imgbox.com/9d/65/BIZM1B5u_o.gif

Wow it looks to be intensifying again I agree. Might a deeper storm get pulled more north into the islands?

[OahuWahine]

So I've been wondering, if the GFS was the only model that was showing Lane moving to the north toward the islands, why isn't it being taken more into consideration with the current track? For a couple runs now it has taken Lane into Maui, but Maui isn't really even in the cone.

[NotoSans]

So I've been wondering, if the GFS was the only model that was showing Lane moving to the north toward the islands, why isn't it being taken more into consideration with the current track? For a couple runs now it has taken Lane into Maui, but Maui isn't really even in the cone.

The cone does not really reflect forecast uncertainty. It is constructed using the mean track forecast error over the past five years, but not based on the spread among different model guidance, nor ensemble spread. Just keep in mind that the effects of a tropical cyclone can extend well away from the cone, and, as mentioned above, rain is going to pose a significant threat to the Hawaiian islands as well. Look at the warnings issued by your local NWS would help, and make sure preparation work is done as soon as possible.

[Yellow Evan]

----- Current Analysis -----
Date : 22 AUG 2018 Time : 160000 UTC
Lat : 15:05:24 N Lon : 155:30:35 W


CI# /Pressure/ Vmax
6.2 / 944.6mb/119.8kt


Final T# Adj T# Raw T#
6.2 6.5 6.5

Estimated radius of max. wind based on IR : 17 km

Center Temp : +10.9C Cloud Region Temp : -69.8C

Scene Type : EYE

[tolakram]

So I've been wondering, if the GFS was the only model that was showing Lane moving to the north toward the islands, why isn't it being taken more into consideration with the current track? For a couple runs now it has taken Lane into Maui, but Maui isn't really even in the cone.

The cone is a simple mathematical equation that factors in historic errors based on forecast points. Maui is under hurricane warnings, that's all that counts right now. The tracks is a blend of models, some given more weight than others. GFS is not one of the top models for storm tracks but 'm sure it's taken into account. In other words, if the GFS didn't exist the forecast tracks would probably be further away from the islands. The blend almost always does better than any single model.

[Yellow Evan]

T7.0.

[boulderrr]

12Z HWRF is quite a bit west of the 06Z.

[wxman57]

So I've been wondering, if the GFS was the only model that was showing Lane moving to the north toward the islands, why isn't it being taken more into consideration with the current track? For a couple runs now it has taken Lane into Maui, but Maui isn't really even in the cone.

First of all, ignore that cone - it has absolutely nothing to do with the current level of track uncertainty. It simply identifies that 66.7% of the time over the past 5 seasons, the center tracked within that cone. The time has long passed to replace the cone with a probabilistic polygon that DOES reflect current track uncertainty. As for why forecasters aren't giving more weight to the GFS, it's because the GFS is pretty much an outlier here. It's the extreme. It's always better to go with a model consensus than to use any single model.

Here (below), I plotted all the latest GFS ensembles (green) and European (purple). That's 72 different tracks, none of which takes Lane into the Big Island and only one or two take Lane into Maui. The GFS is east of all of its ensemble members as well. The dark reddish line is the official CPHC track, which is more or less a consensus from all the models and ensembles. The consensus may actually be a little left of the official track.

[Aric Dunn]

12Z HWRF is quite a bit west of the 06Z.

about 20 miles.. just far enough not hit the big island.. heading for Oahu with a pressure of 954mb..

well the island next to Oahu..

[Macrocane]

After the brief weakeking Lane seems to be intensifying again, the cloud tops are cooling and the core is becoming more symmetric again.

[boulderrr]

12Z HWRF goes into Maui.

[Aric Dunn]

HWRF 970mb landfall on the islands between Oahu and the big island.

[OahuWahine]

Thanks for the explanations. The thing is, that's not at all how the news media is relaying the information. To the average person that doesn't know anything about global models, they are relying solely on this one track and the weather forecasters have always said that the hurricane will be somewhere within this cone at each particular point in time. I don't think I've ever heard anyone suggest that it could be outside of that cone. So my point being, a lot of people are going to assume that Maui is safe, at least from a direct landfall. I just wish they were explaining things to us as thoroughly as you all have done here.

[ncapps]

Why are airlines still flying into Kona? Have to imagine the cutoff for flights to BI is within the next hour or so.

[boulderrr]

12Z HMON no longer threatens Oahu like the 06Z did.

[Alyono]

all recon has been cancelled

[cjrciadt]

all recon has been cancelled

What the!!!!!!

[pgoss11]

all recon has been cancelled

Because???

[supercane4867]

all recon has been cancelled

Because???

Because Lane is heading toward their base?

[NotoSans]

all recon has been cancelled

Because???

The planes need to evacuate now. Reasonable to me because safety is always of utmost importance.