ATL: DORIAN - Post-Tropical - Discussion

[sphelps8681]

https://www.facebook.com/photo.php?fbid=2580880142027333&set=a.112570355525003&type=3&theaterJust a tip for those in the path of this hurricane.

[Cee235]

Hi!! I made an account years ago but forgot my login. I’m in Melbourne. What should I be expecting? I’ve been dealing with an eye injury for 2 days and haven’t kept up. Did stock up on water though

[ozonepete]

NHC will have to shift the track south this next advisory with the latest GFS track coming more in line with the UK and European models.

They won't shift south on one 18Z GFS model run. With many of the models and ensembles showing a hard right and slow speed near or over Florida the uncertainty at days 4 and 5 is only increasing. You don't make a big shift on day 5 with that kind of uncertainty. NHC will play it safe here until they see the evening run output from GFS and Euro.

[Hammy]

Big dry slot in the west, hopefully this can keep the intensity in check.

[Blinhart]

NHC will have to shift the track south this next advisory with the latest GFS track coming more in line with the UK and European models.

They won't shift south on one 18Z GFS model run. With many of the models and ensembles showing a hard right and slow speed near or over Florida the uncertainty at days 4 and 5 is only increasing. You don't make a big shift on day 5 with that kind of uncertainty. NHC will play it safe here until they see the evening run output from GFS and Euro.

I will politely disagree with you, if they do any adjustments to the track it will be to the South, but most likely since there isn't any watches or warnings right now, they won't make any adjustments to any of the track until the normal time (11 pm) and then they will adjust it south.

[Bocadude85]

Just look how much slower the 5 day forecast has gotten between two days ago and now:

https://i.imgur.com/sMDCxTA.png
https://i.imgur.com/Z9OeZMF.png

It's like it's trying to lengthen its lifespan as much as possible!

At 5PM the NHC slowed the track down and brought it south.
Buys them some time to get tonight's data into the models.
They apparently will be looking at vertical profiles over Bermuda, and Nassau in
the Bahamas.
Maybe Levi will have some insight tonight?

The track was not brought south.

The track was shifted slightly south.

“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.”

https://www.nhc.noaa.gov/text/refresh/MIATCDAT5+shtml/292047.shtml

[ozonepete]

At 5PM the NHC slowed the track down and brought it south.
Buys them some time to get tonight's data into the models.
They apparently will be looking at vertical profiles over Bermuda, and Nassau in
the Bahamas.
Maybe Levi will have some insight tonight?

The track was not brought south.

I thought the disco said it was

The distance was so small you can't see it by eye on the 11AM and 5PM track maps. So I should have said it's negligible. I just don't want people reading on here that the track was shifted southward and thinking it was important in any way. Too many people are looking at day 5 like it was day 3. Day 5 has a very large error in location.

[ozonepete]

At 5PM the NHC slowed the track down and brought it south.
Buys them some time to get tonight's data into the models.
They apparently will be looking at vertical profiles over Bermuda, and Nassau in
the Bahamas.
Maybe Levi will have some insight tonight?

The track was not brought south.

The track was shifted slightly south.

“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.”

https://www.nhc.noaa.gov/text/refresh/MIATCDAT5+shtml/292047.shtml

Slightly is the understatement of the year. See my prior post.

[wjs3]

NHC will have to shift the track south this next advisory with the latest GFS track coming more in line with the UK and European models.

They won't shift south on one 18Z GFS model run. With many of the models and ensembles showing a hard right and slow speed near or over Florida the uncertainty at days 4 and 5 is only increasing. You don't make a big shift on day 5 with that kind of uncertainty. NHC will play it safe here until they see the evening run output from GFS and Euro.

How are you, old friend?

Nope, you don't make a big shift, but--unless the ensembles say otherwise--I think a "nudge" south is prudent, maybe? At least based on the data so far?

[ozonepete]

NHC will have to shift the track south this next advisory with the latest GFS track coming more in line with the UK and European models.

They won't shift south on one 18Z GFS model run. With many of the models and ensembles showing a hard right and slow speed near or over Florida the uncertainty at days 4 and 5 is only increasing. You don't make a big shift on day 5 with that kind of uncertainty. NHC will play it safe here until they see the evening run output from GFS and Euro.

I will politely disagree with you, if they do any adjustments to the track it will be to the South, but most likely since there isn't any watches or warnings right now, they won't make any adjustments to any of the track until the normal time (11 pm) and then they will adjust it south.

So where did we disagree? lol.

[Kingarabian]

We'll know for sure when recon gets there but the inner core continues to look largely the same. The eyewall not completely organized and overshooting tops are clouding the eye. It's been consistently trying to mix out dry air all day, so that's probably the reason why.

[AutoPenalti]

There’s been noticeably drier than normal air near the Bahamas.

[EquusStorm]

With dry air still causing issues, I wonder if it's going to be able to get organized overnight; it's a pretty constant cycle of slowly mixing out the dry air, trying to organize, and sucking in a dry slot again as long as it's close enough to the Caribbean to keep drawing it in. Of course that could mean RI doesn't start until later which gives it less time to weaken and cycle before landfall...

[ronjon]

Ozonepete agree...NHC takes a conservative approach and will wait to digest the 00z model suite before adjusting track. The 00z model runs will all have the benefit of all the upper air sampling and hopefully the speed issue is better resolved (or closer than euros left curve today). It would not surprise me now if the trend is further west with time and that Dorian makes it into the GOM with a faster solution aka UKMET and HWRF.

[hipshot]

https://www.facebook.com/photo.php?fbid=2580880142027333&set=a.112570355525003&type=3&theaterJust a tip for those in the path of this hurricane.

What a great idea, thanks for sharing. I won't need it but I'll bet someone can use it.

[ozonepete]

NHC will have to shift the track south this next advisory with the latest GFS track coming more in line with the UK and European models.

They won't shift south on one 18Z GFS model run. With many of the models and ensembles showing a hard right and slow speed near or over Florida the uncertainty at days 4 and 5 is only increasing. You don't make a big shift on day 5 with that kind of uncertainty. NHC will play it safe here until they see the evening run output from GFS and Euro.

How are you, old friend?

Nope, you don't make a big shift, but--unless the ensembles say otherwise--I think a "nudge" south is prudent, maybe? At least based on the data so far?

Hello old friend!

The problem is the track at days 4 and 5 is highly suspect. It's going to move west-northwestward into the northern Bahamas, then turn west-southwest, but only for a few hours (!), then make a sharp right to due north. The sharp right and slow down always indicate model uncertainty that isn't resolved until day 3, which is terrible for Florida because day 3 keeps moving away. But those kind of tracks at day 4 and 5 almost never pan out. And imo most later day right turn forecasts for FL hurricanes forecast the turn too late. I just want to be more certain of what the STR is going to do.

P.S. And of course the models have realy blown the track so far and seem like they are still not doing that well. Any movement now more north than forecast is going to start to force a more northward landfall, even if the ridge strengthens.

[Hurricane Jed]

Definitely one of the trickier systems I’ve tracked in 20+ years of following storms.

[ozonepete]

Btw, in light of my P.S. in my last post there, I don't want to leave out that the ULL which is currently steering Dorian NW is still a key player. It could move more slowly and push Dorian further north tomorrow or move SW faster and allow Dorian to track more westward faster. It must be watched closely.

[robbielyn]

Just in the off chance this misses FL, or rides the coast, for all of us who got our supplies ready gassed up, bought a generator, made plans where to go for safety including animals, we will be set for the next one, as we haven’t even made it to peak season yet. It will be a good dry run and got us all stocked up. so if some of us get no affects be glad you are now prepared for the rest of the season.

[wjs3]

How are you, old friend?

Nope, you don't make a big shift, but--unless the ensembles say otherwise--I think a "nudge" south is prudent, maybe? At least based on the data so far?

Hello old friend!

The problem is the track at days 4 and 5 is highly suspect. It's going to move west-northwestward into the northern Bahamas, then turn west-southwest, but only for a few hours (!), then make a sharp right to due north. The sharp right and slow down always indicate model uncertainty that isn't resolved until day 3, which is terrible for Florida because day 3 keeps moving away. But those kind of tracks at day 4 and 5 almost never pan out. And imo most later day right turn forecasts for FL hurricanes forecast the turn too late. I just want to be more certain of what the STR is going to do.

P.S. And of course the models have realy blown the track so far and seem like they are still not doing that well. Any movement now more north than forecast is going to start to force a more northward landfall, even if the ridge strengthens.

The uncertainty is killing me. I tried to describe the possible range of outcomes to some people earlier today (I won't repeat those outcomes here. I'll get roasted) and they laughed me off. Massively uncertain.

imo you have to respect the latest GFS and Euro (pending 18z Euro) and nudge south. Maybe slow it down too. Maybe both. Nudge.

As more synoptic data gets ingested into models (more balloon launches and G-IV sampling) and the players get on the field so to speak, things should stabilize. At least that's my theory!

Always good to talk to you!