ATL: MICHAEL - Post-Tropical - Discussion

[xironman]

The two mesos going around now seem to be signaling the development of a huge (outer?) eye.

[Hammy]

Looks like a large eye setting up, but also a huge dry slot to the NW.

[BobHarlem]

Casablanca radar.
La Bajada is down.

http://www.insmet.cu/asp/genesis.asp?TB ... AXw01a.gif

https://flhurricane.com/imageanimator.php?402 is a composite of radars in the area, but it's *very" spotty

[NDG]

Zoomed in vis satellite loop of the eye, the eastern eyewall is over the western tip of Cuba.

[tolakram]

The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal.

I don't mind you giving an opinion, but can you really back up this statement? HWRF is one of the few models to show consistent intensity skill at 3 days. The NHC goes over these stats every year, you can find them on their web page.



That's 110kts at landfall. Can you identify the other models you used?

Here's the NHC 2017 review

An evaluation over the three years 2015-17 (Fig. 11) indicates that the official forecasts
have been consistently performing quite well, but they were outperformed by FSSE from 12 to 72
h and by HCCA from 48 to 120 h. Similar to 2017, HWFI was the best individual model, followed
by LGEM and DSHP.
The 48-h official intensity error, evaluated for all tropical cyclones, is another GPRA
measure for the NHC. In 2017, the GPRA goal was 12 kt and the verification for this measure
was slightly higher, 12.6 kt.

https://www.nhc.noaa.gov/verification/pdfs/Verification_2017.pdf

[xironman]

Looks like a large eye setting up, but also a huge dry slot to the NW.

That will close off once the storm off the tip of Cuba comes around.

[cycloneye]

SAB up to 4.5.

TXNT22 KNES 081758
TCSNTL

A. 14L (MICHAEL)

B. 08/1747Z

C. 21.7N

D. 84.9W

E. THREE/GOES-E

F. T4.5/4.5/D2.0/24HRS

G. IR/EIR/VIS

H. REMARKS...10.5/10 BANDING RESULTS IN A DT OF 4.0. MET IS ALSO 4.0
BASED ON RAPID DEVELOPMENT OVER THE LAST 24 HOURS. PT IS 4.5. FT IS
BASED ON PT BECAUSE BANDING FEATURES ARE NOT CLEAR CUT.

I. ADDL POSITIONS

NIL


...TURK

[xironman]

Gonzo on the way in.
I hope they show their live radar.

That plane is doing synoptic measurements. I am not seeing mission 4.

[vbhoutex]

GBPackman thanks for your thorough analysis. Right or wrong, this is the type of thought I like to see put into these posts. Can't find much to disagree with in your post. Here in Texas the talk is that the first incoming "front" is indeed going to to hold back and or stall/start to dissipate before it even makes it to Houston. If so then you might have nailed landfall or be a little too far East, but not too much.
I grew up in Gulf Breeze and just enjoyed a great week at PB. Glad I am not there now, except if I was they would probably have to drag me off the beach since I would have a front row seat. And yes I do know better!!

[Aric Dunn]

there is a synoptic recon flight out there now that mill make it into the 18z and 00z runs so that will help with steering at least.

[GCANE]

Amazing how 355K PV is clearing out in the GOM.
Will allow the vort column to stack and expand vertically.

At this point, not much to impede intensification.
Currently, two eyewall towers firing off, 180 degrees from each other.

[GBPackMan]

The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal.

I don't mind you giving an opinion, but can you really back up this statement? HWRF is one of the few models to show consistent intensity skill at 3 days. The NHC goes over these stats every year, you can find them on their web page.

That's 110kts at landfall. Can you identify the other models you used?

Some models do well at path, not so much at directional speed or intensity, some do well with intensity but not so much the path or speed, etc. HWRF is one that has done well with intensity, but not so well with path or movement speed. This is where GFS and the Euro model have fared better the last few years.
So looking at the models that have a fairly consistent past accuracy with intensity, points to a high likelihood of a strong Cat 1 being the most likely scenario, with possible bump into Cat 2 before dropping off 12-18h before landfall. Almost all of them show the intensity either leveling or dropping off from 36-48h (from 12z Oct 8 model runs). The 18z should be coming out soon so this may change.

Still, with the cooler night time autumn air over the southeastern US, plus the cooler outflow from the jet stream with the southern point slowly adjusting NNE getting drawn into the storm around 24h before landfall, this points to a decent weakening. This is why I believe a weak Cat 2, then approx 24h before landfall the cooler drier air being drawn in weakening it to 80-90mph max winds within a narrow area of the eye.

[meriland29]

GBPackMan: "The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal. The extreme outlier models that haven't ever been correct are pushing the strength into the weak Cat 3 level, and some other outliers that are never right having it drop from Cat 1 back to TS by Tuesday morning until landfall (better chance of this happening than seeing a Cat 3). The rest of the models that are much more trustworthy and tend to be much closer to what really happens with past mid-late season storms, are keeping it as a mid to strong Cat 1 at landfall (80-90mph). Intensity info easily found on tropicaltidbits."

That would be a great outcome, but I truly believe this depends on how strong Michael gets at peak intensity. I have serious doubts he will degrade into a 1 or less at landfall. IMO a 2 or more seems more and more likely as time progresses, and the NHC is coming more into that agreement after every advisory update.

[meriland29]

The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal.

I don't mind you giving an opinion, but can you really back up this statement? HWRF is one of the few models to show consistent intensity skill at 3 days. The NHC goes over these stats every year, you can find them on their web page.

That's 110kts at landfall. Can you identify the other models you used?

https://imgur.com/ENW4YVt


Some models do well at path, not so much at directional speed or intensity, some do well with intensity but not so much the path or speed, etc. HWRF is one that has done well with intensity, but not so well with path or movement speed. This is where GFS and the Euro model have fared better the last few years.
So looking at the models that have a fairly consistent past accuracy with intensity, points to a high likelihood of a strong Cat 1 being the most likely scenario, with possible bump into Cat 2 before dropping off 12-18h before landfall. Almost all of them show the intensity either leveling or dropping off from 36-48h (from 12z Oct 8 model runs). The 18z should be coming out soon so this may change.

Still, with the cooler night time autumn air over the southeastern US, plus the cooler outflow from the jet stream with the southern point slowly adjusting NNE getting drawn into the storm around 24h before landfall, this points to a decent weakening. This is why I believe a weak Cat 2, then approx 24h before landfall the cooler drier air being drawn in weakening it to 80-90mph max winds within a narrow area of the eye.

If you look at the intensity forecast for this specific storm the past 2 days you will see a gradual uptick for every update. Yesterday the max expected in all of the models was a moderate cat 2.

[artist]

The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal.

I don't mind you giving an opinion, but can you really back up this statement? HWRF is one of the few models to show consistent intensity skill at 3 days. The NHC goes over these stats every year, you can find them on their web page.

That's 110kts at landfall. Can you identify the other models you used?

https://imgur.com/ENW4YVt


Some models do well at path, not so much at directional speed or intensity, some do well with intensity but not so much the path or speed, etc. HWRF is one that has done well with intensity, but not so well with path or movement speed. This is where GFS and the Euro model have fared better the last few years.
So looking at the models that have a fairly consistent past accuracy with intensity, points to a high likelihood of a strong Cat 1 being the most likely scenario, with possible bump into Cat 2 before dropping off 12-18h before landfall. Almost all of them show the intensity either leveling or dropping off from 36-48h (from 12z Oct 8 model runs). The 18z should be coming out soon so this may change.

Still, with the cooler night time autumn air over the southeastern US, plus the cooler outflow from the jet stream with the southern point slowly adjusting NNE getting drawn into the storm around 24h before landfall, this points to a decent weakening. This is why I believe a weak Cat 2, then approx 24h before landfall the cooler drier air being drawn in weakening it to 80-90mph max winds within a narrow area of the eye.

I personally think you might be forgetting the storm surge effect.

[nativefloridian]

The 3 most trusted intensity models based on the 12z Oct 8 runs paint this as a mid to strong Cat1 (80-90 mph), with lower potential of weak Cat 2 at or close to landfall (90-100mph). There is better potential of intensifying to Cat 2 within 24-36 hours before landfall, but dropping back off to Cat 1 as it gets closer to land. Nowhere close to Cat 3-4 Opal.

I don't mind you giving an opinion, but can you really back up this statement? HWRF is one of the few models to show consistent intensity skill at 3 days. The NHC goes over these stats every year, you can find them on their web page.

That's 110kts at landfall. Can you identify the other models you used?

Here's the NHC 2017 review

An evaluation over the three years 2015-17 (Fig. 11) indicates that the official forecasts
have been consistently performing quite well, but they were outperformed by FSSE from 12 to 72
h and by HCCA from 48 to 120 h. Similar to 2017, HWFI was the best individual model, followed
by LGEM and DSHP.
The 48-h official intensity error, evaluated for all tropical cyclones, is another GPRA
measure for the NHC. In 2017, the GPRA goal was 12 kt and the verification for this measure
was slightly higher, 12.6 kt.

https://www.nhc.noaa.gov/verification/pdfs/Verification_2017.pdf

With all due respect the poster did start out by saying....."Remember this is just my opinion, so take it as such..." despite not ending their post with the disclaimer. I personally don't mind reading other's opinions on hurricanes, models, and the atmospheric influences that affect their course, strength, and/or demise.

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

[cheezyWXguy]

Michael's satellite appearance is interesting. Looks like its starting to get rounder, and the band wrapping around it to the east seems to be gradually wrapping into the storm, instead of remaining almost a separate entity. However, there is quite a large dry slot between Michael's inner core and outer banding on the N quadrant. This is observed on mimic as well, and I am wondering if such a prominent band would flatten the pressure gradient, preventing the inner core from tightening and the winds from catching up if Michael's pressure continues to fall.

[supercane4867]

For the future intensity of Michael, I think there are three possible options:

1) RI in the southern gulf, then weakens on approach to the gulf coast due to EWRC and shear like most major hurricanes did (Opal, Ivan, Katrina, etc.)

2) Can't get its act together until approaching the coast because of large size and shear, RI in the last minute fueled by poleward outflow jet from the incoming trough (Eloise)

3) RI in the southern gulf, completes an EWRC before approaching land and re-intensifies up to landfall (Camille)


Based on current trend, 1 seems most likely at this point. 3 is also possible depending on forward speed.

[tolakram]

Some models do well at path, not so much at directional speed or intensity, some do well with intensity but not so much the path or speed, etc. HWRF is one that has done well with intensity, but not so well with path or movement speed. This is where GFS and the Euro model have fared better the last few years.
So looking at the models that have a fairly consistent past accuracy with intensity, points to a high likelihood of a strong Cat 1 being the most likely scenario, with possible bump into Cat 2 before dropping off 12-18h before landfall. Almost all of them show the intensity either leveling or dropping off from 36-48h (from 12z Oct 8 model runs). The 18z should be coming out soon so this may change.

Still, with the cooler night time autumn air over the southeastern US, plus the cooler outflow from the jet stream with the southern point slowly adjusting NNE getting drawn into the storm around 24h before landfall, this points to a decent weakening. This is why I believe a weak Cat 2, then approx 24h before landfall the cooler drier air being drawn in weakening it to 80-90mph max winds within a narrow area of the eye.

This should probably be in the models thread. The problem I have with that chart is that it gives equal weight to the good and bad models for intensity.

The 18Z chart should be used for the 12Z runs, but the values are similar.



One of the reasons intensity forecasts are so bad is that most models are bad. The HWRF is one of the few that comes closer, the Florida State Super Ensemble is the best, and as the NHC discussed outperformed the NHC intensity forecast. In past years the NHC has had a low bias, and in the latest discussion they revealed they were on the high side of guidance. So with that said I could easily see a moderate to strong cat 2 rather than a cat 3, but not a weak cat 2. In my opinion, of course.

[xironman]

Add in the fall temperatures over land in the southeastern US dipping into the 60s at night getting drawn into the storm.

I took a look at Columbus GA http://www.nws.noaa.gov/cgi-bin/mos/getmav.pl?sta=KCSG and it is still pretty warm an humid. Low Wednesday around 75 and dews close to 70.