ATL: MICHAEL - Post-Tropical - Discussion

[Aric Dunn]

From the 11:00 NHC discussion:

The HWRF model is the most robust of the intensity guidance and makes Michael a category 4 hurricane just prior to landfall. However, all of global models and the HWRF and HMON regional models are indicating westerly to west-northwesterly shear keeping the upper-level outflow restricted to the eastern semicircle, which is not a pattern conducive for the development of an intense hurricane. Therefore, the HRWF intensity solution has been discounted, and the new official intensity forecast remains similar to the previous advisory, which is close to but a little lower than the IVCN and ICON intensity consensus models. Although the 72-h forecast shows a decrease to 75 kt, this is due to the cyclone being inland, and should not be interpreted as being an indication of a weakening trend prior to landfall.

technically they are discounting all model intensity guidance exept IVCN and ICON. being that EURO and GFS show a cat 3 borderline cat 4.... so yeah..

[TheStormExpert]

From the 11:00 NHC discussion:

The HWRF model is the most robust of the intensity guidance and makes Michael a category 4 hurricane just prior to landfall. However, all of global models and the HWRF and HMON regional models are indicating westerly to west-northwesterly shear keeping the upper-level outflow restricted to the eastern semicircle, which is not a pattern conducive for the development of an intense hurricane. Therefore, the HRWF intensity solution has been discounted, and the new official intensity forecast remains similar to the previous advisory, which is close to but a little lower than the IVCN and ICON intensity consensus models. Although the 72-h forecast shows a decrease to 75 kt, this is due to the cyclone being inland, and should not be interpreted as being an indication of a weakening trend prior to landfall.

technically they are discounting all model intensity guidance exept IVCN and ICON. being that EURO and GFS show a cat 3 borderline cat 4.... so yeah..

Sounds like shear should keep him in check some. Latest shear tendency shows it increasing in his path not decreasing.

[cycloneye]

Center is consolidating south of western Cuba and notice the intense convective band beginning to wrap into the center from the west.

[=https://imgur.com/ict1yTA]http://i.imgur.com/ict1yTA.gif [/url]

Ozonepete where do you think the center is? I think it is definitely east of 85W. I am thinking 84.7 or so.

Recon is on it's way to Michael so around 1:00 AM - 1:30 AM we will know where it really is.

[blp]

Center is consolidating south of western Cuba and notice the intense convective band beginning to wrap into the center from the west.

[=https://imgur.com/ict1yTA]http://i.imgur.com/ict1yTA.gif [/url]

Ozonepete where do you think the center is? I think it is definitely east of 85W. I am thinking 84.7 or so.

Recon is on it's way to Michael so around 1:00 AM - 1:30 AM we will know where it really is.

Thanks Cycloneye. Hopefully I can stay up till then.

[caneman]

I too believe it is actually East of 85. I fear more East shifts.

[Stormcenter]

Maybe if it keeps on shifting east it will miss all of Florida.

I too believe it is actually East of 85. I fear more East shifts.

[caneman]

Maybe if it keeps on shifting east it will miss all of Florida.

I too believe it is actually East of 85. I fear more East shifts.

I wish. This is hitting someone

[AutoPenalti]

I’m actually a tad bit worried now. People in SE FL should probably watch this as well.

[bamajammer4eva]

Looks like NHC forecast is using Euro for track and GFS for timing

[caneman]

Looks like NHC forecast is using Euro for track and GFS for timing

Not how I read it. I read it that they were giving deference to the UKMET

[SoupBone]

Forgive me, because I've been away a few days, but while the shear surrounding him has dropped some, he has a massive amount of shear, on the increase, directly in front of him. Some small pockets of 60 knot shear. Is it being forecast to quickly vanish?

[ConvergenceZone]

From the 11:00 NHC discussion:

technically they are discounting all model intensity guidance exept IVCN and ICON. being that EURO and GFS show a cat 3 borderline cat 4.... so yeah..

Sounds like shear should keep him in check some. Latest shear tendency shows it increasing in his path not decreasing.

Wait, I though the shear suppose to be decreasing? At least that's what a couple of the Mets were saying, hence the strong intensity forecast. Are you saying that now it's changed as the shear suppose to be strong?

[cycloneye]

 https://twitter.com/RyanMaue/status/1049139084655038465

[Aric Dunn]

https://twitter.com/RyanMaue/status/1049139084655038465

yeah this sums it up.. the NHC is going against all the reliable models in terms of intensity and are leaning towards the UKMET track, not intensity since UKMET is stronger than the ICON. I have to say it is the strangest thing I have seen the NHC do..

[psyclone]

Tampa's ts wind probs went up to 45% but for 50kt winds the number is still low at 9. Cedar key ts probs up to 70%. If the storm lands near Apalachicola the bay area/nature coast may get grazed by the gale windfield but it will be the water rise at the coast that could be problematic. Our trees got a good workover from Irma last year. there's still a lot of longitude between the west coast and the current nhc track...

[ConvergenceZone]

https://twitter.com/RyanMaue/status/1049139084655038465

This make no sense!! if the NHC is expecting shear to keep it from intensifying much, then why are they taking it up to 100mph? That doesn't make any sense...

[Hammy]

https://twitter.com/RyanMaue/status/1049139084655038465

yeah this sums it up.. the NHC is going against all the reliable models in terms of intensity and are leaning towards the UKMET track, not intensity since UKMET is stronger than the ICON. I have to say it is the strangest thing I have seen the NHC do..

They did this with Matthew in 2016 as well if I remember correctly--the models had simultaneously shown shear and intensification, and they went with the former over the latter when it strengthened well beyond forecast despite the shear.

[SoupBone]

https://twitter.com/RyanMaue/status/1049139084655038465

yeah this sums it up.. the NHC is going against all the reliable models in terms of intensity and are leaning towards the UKMET track, not intensity since UKMET is stronger than the ICON. I have to say it is the strangest thing I have seen the NHC do..

They did this with Matthew in 2016 as well if I remember correctly--the models had simultaneously shown shear and intensification, and they went with the former over the latter when it strengthened well beyond forecast despite the shear.

Was the shear surrounding Matthew 40-50kts? My amateur thinking but unless it just simply vanishes, and quickly, Michael will be dealing with west to east screaming shear. Are the shear forecasts showing it diminishing quickly within the next 2 days?

[Rail Dawg]

Harvey kicked up to a Cat 4 very quickly before striking Texas.

Few saw that happening.

Forecast tracks I trust.

Forecast intensities I do not.

[kthmcc7319]

Harvey kicked up to a Cat 4 very quickly before striking Texas.

Few saw that happening.

Forecast tracks I trust.

Forecast intensities I do not.

I agree with your point. My very amateur analysis is that models are generally good at forecasting storm tracks (some better than others) but often miss on storm intensity. That being said, what is your take on Michael’s intensity as it approaches the CONUS?