ATL: HERMINE - Post-Tropical - Discussion

[RL3AO]

What effect would that have on 09L?

Very likely would see a convective ramp up when it tracks into it.

GCANE, do you know if any of the models can process Theta-E Ridge data and incorporate it into their tracks to show what kind of effect it would have on the developing system?

Theta-e is a basic thermodynamic quantity. It's the temperature a parcel would have if lifted adiabatically to the top of the atmosphere and brought down again to 1000 mb. From my thunderstorm forecasting experience, a theta-e ridge is useful for forecasting where convection may develop BEFORE there are any storms. Of course there is higher theta-e values ahead of the system. That's because there are lower theta-e values underneath the convection (because it's cooler).

Plus theta-e only lifts a parcel from a certain level (surface, 1000 mb, 850 mb etc). It's not going to tell you anything about mid-level dry air, wind shear, jet level divergence, etc. All are much more important things to look at IMO.

[otterlyspicey]

new hwrf is slower and more west initially then accelerates quickly the last day before landfall. interesting.

And much weaker. Who knows what's going on. Lol

[JaxGator]

new hwrf is slower and more west initially then accelerates quickly the last day before landfall. interesting.

And much weaker. Who knows what's going on. Lol

Besides track, it's more nowcasting on intensity but yes, interesting model run.

[chaser1]

I'm thinking that a slightly more westward motion in the near term, coupled with a weaker than anticipated trough would spell a greater threat for points west of Tallahassee. Its all conjecture still at least up to when we finally have a better defined storm on our hands (which might be fairly soon but have to wait and see).

[JaxGator]

Levi says the eastern side is good while Cuba is still inhibiting the inflow but other than that, it looks good (but it also shows the center almost being clear of Cuba too).
The storm looks healthy.

[Aric Dunn]

also the models initialized it a little far to the north by about 30 to 50 miles.. or like the gfs like 100 miles to far west. the hwrf initialized an open wave... guess we have to keep waiting..

[Dave C]

Nice feeder band forming from the west side.

[StormHunter72]

All this speculation is confusing. I am sure the NHC has a handle on this.

[wxman57]

also the models initialized it a little far to the north by about 30 to 50 miles.. or like the gfs like 100 miles to far west. the hwrf initialized an open wave... guess we have to keep waiting..

Your statement about the poor initialization made me curious so I took a look at the 12Z initialization. I'm looking at a high-res plot of the 12Z EC & GFS, with pressure plotted at 1/2 mb increments (I can plot pressure down to 0.1mb increments). The 12Z GFS initialized the center at 23.08N / 84.95W. The EC had it at 23.62N / 84.76W. The Euro is a bit closer than the GFS, which is too far south. Both initialized it pretty well, I think.

[chaser1]

Levi says the eastern side is good while Cuba is still inhibiting the inflow but other than that, it looks good (but it also shows the center almost being clear of Cuba too).
The storm looks healthy.

Definitely seems to be inhibiting a southerly inflow, but not enough to retard what appears to be a CDO over center. Interestingly and for the first time, we're now beginning to see some semblance of a feeder band attempting to develop to the west. If such a band were to continue to expand and maintain itself prior to being knocked down by shear, than this would seemingly help to import an additional flow of moist air. This, and aid moisten drier air to the systems' west too. I think here is where we might see the greatest evidence that T.D. 9 is not only becoming distinctly better organized but also potentially developing a deeper and broader envelope that would in turn effectively insulate a developing T.S. from light vertical shear

[CrazyC83]

000
URNT15 KWBC 291802
NOAA3 0709A CYCLONE HDOB 07 20160829
175230 2510N 08554W 6457 03839 0073 +079 +026 065014 014 018 000 00
175300 2509N 08556W 6442 03857 0074 +078 +027 063014 014 020 000 03
175330 2508N 08558W 6421 03881 0073 +077 +033 062014 015 021 000 00
175400 2507N 08600W 6435 03864 0073 +078 +033 063015 015 020 000 00
175430 2506N 08602W 6438 03863 0070 +082 +029 066015 016 021 000 03
175500 2506N 08605W 6427 03878 0072 +080 +027 065015 017 021 000 00
175530 2506N 08607W 6429 03870 0075 +076 +036 064016 016 021 000 00
175600 2506N 08610W 6448 03846 0072 +078 +037 061016 016 021 000 00
175630 2506N 08612W 6455 03838 0074 +079 +033 056018 019 022 000 00
175700 2506N 08614W 6440 03859 0078 +076 +034 054019 019 021 000 03
175730 2505N 08616W 6476 03815 0074 +081 +044 060019 019 014 001 03
175800 2503N 08615W 6447 03851 0075 +077 +038 062019 020 017 000 03
175830 2502N 08614W 6447 03849 0075 +075 +039 062019 020 017 000 00
175900 2500N 08612W 6438 03862 0076 +075 +036 064018 019 018 000 00
175930 2459N 08611W 6488 03793 0075 +079 +034 061019 020 017 000 03
180000 2457N 08609W 6778 03433 0079 +098 +036 053016 017 018 000 03
180030 2457N 08607W 7116 03025 0086 +116 +065 058018 019 014 002 03
180100 2457N 08604W 7476 02610 0090 +142 +092 065019 019 /// /// 03
180130 2456N 08602W 7949 02099 0101 +163 +141 066018 018 /// /// 03
180200 2454N 08601W 8191 01837 0102 +177 +152 062018 018 022 000 03

Descending to operational altitude. I can watch this for about 45 minutes.

[DucaCane]

Hello everyone. Long time lurker, first time poster from SE LA. I do have a question. Since most computer models already have TD9 on a wnw to nw track, how will it's current wsw movement affect the result? We all remember what wsw did to Katrina.

[Aric Dunn]

also the models initialized it a little far to the north by about 30 to 50 miles.. or like the gfs like 100 miles to far west. the hwrf initialized an open wave... guess we have to keep waiting..

Your statement about the poor initialization made me curious so I took a look at the 12Z initialization. I'm looking at a high-res plot of the 12Z EC & GFS, with pressure plotted at 1/2 mb increments (I can plot pressure down to 0.1mb increments). The 12Z GFS initialized the center at 23.08N / 84.95W. The EC had it at 23.62N / 84.76W. The Euro is a bit closer than the GFS, which is too far south. Both initialized it pretty well, I think.

well I dont have the higher resolution .. the GFS is quite a bit farther west than where it is now..maybe your better resolution fixes the issue idk..

but most of the models were off a little to well quite a bit like the gfs.

[adam0983]

Does anyone think tropical depression 9 can go more to the south and east towards southern Florida since it is moving southwest. Hurricane Charley was supposed to hit Tampa and the went south towards Port Charlotte so anything is possible.

[HurriGuy]

ECMWF more west this run fwiw

[Aric Dunn]

recon descending going for NW to SE pass still about 30 min away.

[JaxGator]

Levi says the eastern side is good while Cuba is still inhibiting the inflow but other than that, it looks good (but it also shows the center almost being clear of Cuba too).
The storm looks healthy.

Definitely seems to be inhibiting a southerly inflow, but not enough to retard what appears to be a CDO over center. Interestingly and for the first time, we're now beginning to see some semblance of a feeder band attempting to develop to the west. If such a band were to continue to expand and maintain itself prior to being knocked down by shear, than this would seemingly help to import an additional flow of moist air. This, and aid moisten drier air to the systems' west too. I think here is where we might see the greatest evidence that T.D. 9 is not only becoming distinctly better organized but also potentially developing a deeper and broader envelope that would in turn effectively insulate a developing T.S. from light vertical shear

Yeah, been seeing that too. Sounds ominous and imo, the models don't have a grasp at all with the strength of this thing. Future Hermine wants to make up her own mind.

[StormHunter72]

Hello everyone. Long time lurker, first time poster from SE LA. I do have a question. Since most computer models already have TD9 on a wnw to nw track, how will it's current wsw movement affect the result? We all remember what wsw did to Katrina.

two totally different systems. this is way further west and conditions don't support a major. Good news for you since yall flooded so bad.

[wxman57]

also the models initialized it a little far to the north by about 30 to 50 miles.. or like the gfs like 100 miles to far west. the hwrf initialized an open wave... guess we have to keep waiting..

Your statement about the poor initialization made me curious so I took a look at the 12Z initialization. I'm looking at a high-res plot of the 12Z EC & GFS, with pressure plotted at 1/2 mb increments (I can plot pressure down to 0.1mb increments). The 12Z GFS initialized the center at 23.08N / 84.95W. The EC had it at 23.62N / 84.76W. The Euro is a bit closer than the GFS, which is too far south. Both initialized it pretty well, I think.

well I dont have the higher resolution .. the GFS is quite a bit farther west than where it is now..maybe your better resolution fixes the issue idk..

but most of the models were off a little to well quite a bit like the gfs.

https://s17.postimg.io/mzne2ixlr/gfs_ms ... 09_L_1.png

That automated chart on Levi's page has the low in the wrong place. If you look at the surface low with the 10m winds plotted then you can see the low is well east of where it was placed on his map.

[Aric Dunn]

also clearly from the resolution i have.. even the Euro is about 75 miles to far to the NW initially..