ATL: HERMINE - Models

[wflamholtz]

A have a theory on why the GFS runs of the past were producing a different result from the EURO for 99L, and I think it lies in 850 mb vorticity. The GFS of the past had a much healthier 850 vorticity maximum 24-36 hours before interacting with the Greater Antilles, while the EURO has a less healthy, but becoming more consolidated, around the same time frame.

Now this matters when the interaction with land occurs, because a healthier, more consolidated vorticity maximum allows a source for self sufficiency for ascent of air as the system exits into the Bahamas. The GFS still had a decently healthy vorticity maximum, while the EURO does not (obviously). But I think there's a piece missing that people haven't mentioned, and it's evident to me in today's 18z GFS run.

Once the vorticity associated with 99L is in the Bahamas, it starts to interact and get stretched by the vorticity associated with he ghost of Fiona. It is not able to consolidate over the favorable environment near the Bahamas. So the think to watch as 99L approaches the PR, we need to see how organizes it gets, which remains to be seen. The strongest performing models say "not much" but we'll have to wait. A stronger vort maximum on the other side of the land interaction will result in resiliency from the ghost of Fiona.

[AJC3]

NHC has bigger tool box than Storm2k... They had 12z Euro run prior to the 2pm update and they still increased 5 day to 60%... Gotta think if they are considering the Euro showing very little and potential future 90L blowing up affecting 99L they would begin lowering 99L's percentages at the 8pm update...

um... NHC does not have the EC prior to their 18Z TDO. The EC arrives at the same time for those who PAY for it. It starts coming in maybe 10 minutes prior to 18Z

Moreover, the centers get the data before the WFO's. In fact, the WFO's actually get model data into AWIPS about 5-10 minutes AFTER paying customers.

[Bocadude85]

18Z HWRF now showing a significant hurricane at 126 hours....much stronger then the past few runs.

http://www.tropicaltidbits.com/analysis/models/?model=hwrf&region=99L&pkg=mslp_wind&runtime=2016082018&fh=126&xpos=0&ypos=527

[Kazmit]

18Z HWRF now showing a significant hurricane at 126 hours....much stronger then the past few runs.

http://www.tropicaltidbits.com/analysis/models/?model=hwrf&region=99L&pkg=mslp_wind&runtime=2016082018&fh=126&xpos=0&ypos=527

All of these runs have been very uncertain, from no development at all, to a raging Cat 5.

[Hammy]

GFS seems to have finally woken up to the poor environment and dropped development.

[Bocadude85]

GFS seems to have finally woken up to the poor environment and dropped development.

I'm still not ready to jump on the no development bandwagon.

[AutoPenalti]

GFS seems to have finally woken up to the poor environment and dropped development.

No model since 4 days ago are correct if there's not even a centerpoint to start at.

[Kingarabian]

When the GFS and the Euro show no development... then there will likely be no development.

[Stormcenter]

None of the models saw Katrina becoming what she diid this far out,just saying.

[Hammy]

None of the models saw Katrina becoming what she diid this far out,just saying.

I would hope the models have vastly improved in eleven years.

[hurricanehunter69]

Check out the impressive and "improving " signature on (mimic-TPW ). Looking at this, I am not at all surprised with the NHC increasing development chances. As for the GFS backing off....I would chalk that up to too much land interaction. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

[cycloneye]

Very tight.

[gatorcane]

00Z intensity guidance:

[blp]

Check out the impressive and "improving " signature on (mimic-TPW ). Looking at this, I am not at all surprised with the NHC increasing development chances. As for the GFS backing off....I would chalk that up to too much land interaction. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

That MIMIC signature is very impressive. I saw that yesterday and it is much better today. You can almost see it trying to absorb Fiona pulling moisture in.

[Hurrilurker]

Looking very much like yet another storm that will get ripped apart by Hispaniola just as it starts to get its act together.

[PTrackerLA]

Very impressive signature on the MMIC TPW. Fiona is downright tiny compared to 99L's moisture envelope. This seems to be well represented in the precipitable water output of the GFS so I would assume the models see what we see as well .

It's also somewhat strange the HWRF shows such a tiny compact system given this large envelope.

[Kazmit]

00Z intensity guidance:

Intensity going back up again...

[WeatherEmperor]

18z Navgem weaker than before. Low/Td above north coast of Hispanola moving WNW

[blp]

Very impressive signature on the MMIC TPW. Fiona is downright tiny compared to 99L's moisture envelope. This seems to be well represented in the precipitable water output of the GFS so I would assume the models see what we see as well .

It's also somewhat strange the HWRF shows such a tiny compact system given this large envelope.

You bring up a great point about the size. The models keep the vorticity very small. Don't know why the disconnect here something has to give.

[Bocadude85]

I was just going through Hurricane Earls model thread and interestingly enough the models showed development for a few days and then dropped development for a few days only to start showing development again, a lot of the same people who are writing 99L off had written 97L off also. Another thing of interest I saw was that the ensembles continued to show development even when the deterministic models had dropped development....just food for thought.