ATL: Ex-NINE - Models

[gatorcane]

Now we are in the long-range but the 12Z ECMWF has it moving slowly NW over Central Cuba...at 192 hours. Again big change from the 00Z ECMWF.

[northjaxpro]

gatorcane wrote:

ECMWF 144 hours has a stronger low south of Cuba and has not merged with the front yet. On the 00Z it was up and away already. Overall the ECMWF is slower and trending closer to the other guidance.

144 hours below:

http://i59.tinypic.com/210djf8.jpg


Yes, 850 vorticity is still stretched out but staying in the NW Carribean this time instead of Bahamas. I think it gets trapped on this run.

Discussed this possible theory on the discussion thread. There is a scenario down the road where the system could get left behind in the NW Caribbean and get trapped by ridging.

[gatorcane]

192 hour 12Z ECMWF graphic below:

[SouthFLTropics]

So South of Cuba and then the fork in the road. Just camped out strengthening and waiting for the next trough to pull it North and Northeast. Classic October setup for a South Florida hit.

SFT

[gatorcane]

Euro 12Z 216 hours:

[DESTRUCTION5]

Euro 12Z 216 hours:

so euro doing opposite of others by weakening instead of blowing up a monster but agrees with GFS a little more timing wise...lots of changes to come....

[gatorcane]

240 hour 12Z ECMWF below. Still around 10 days from now, not sure I buy that!

[SouthFLTropics]

I know the Euro is good but that is a tough pill to swallow to believe that it will still be hanging out 10 days later. With the fronts we've had draped across the SE all year and now starting to see fronts move through bring the start of Fall I can't imagine it doesn't get kicked out before that.

SFT

[chaser1]

I took a look at the loops of 850 mb. vorticity for the GFS, GEM (Canadian) and NAVGEM. The evolution is quite similar in the three models, though the timing is substantially slower in the GFS. In all these models, the main vorticity of 93L moves eastward into the Western Caribbean, where it becomes an intense tropical cyclone. The vorticity that interacts baroclinically with the front and crosses Florida is related to the vorticity of 93L, but is not the core low-level vorticity of 93L. Rather, it is a "streamer" of vorticity away from the core that is baroclinically enhanced while being ejected northeastward.

So according to my best analysis, it is 93L that is coming out of the western Caribbean in these models.

Do you think that scenario is likely to play out? that seems like a rather odd turn of events.

Right now I lean toward the idea that the main vorticity ends up getting ejected eastward. But it is a weak lean. The scenario shown by the 12Z models look plausible. If the ECMWF shows a similar scenario, it will look even more plausible.

I agree with your view BigA; I won't go so far to suggest that I believe what the 12Z GFS is selling however. Where i think the model may have the right idea, is with a slow motion generally towards the east. I also agree with you that what the models are showing in terms of low pressure over the Florida Straits, is seemingly energy or vorticity eminating from 93L, but not the circulation itself. What the GFS appears to be displaying in the long range is not "Son of Hannah" (sounds like a scary Halloween flick), but 93/Hanna itself, LOL

The only way in the world I can see this play out though, is if 93L were to develop into a formidably large strong tropical storm or minimal hurricane before reaching Yucatan and must occur before 60 hours from now. First off, there would just not seem to be any other reasonable way to otherwise be protected from the advecting cooler air dropping into the Gulf shortly after that point. However, if a large enough storm continue to warm the atmosphere, I would think it might temporarily maintain itself within a warm boundary of air. I don't necessarily see the 500mb flow ahead of this front to be all that strong to lift a fairly large system off to the NE. In fact the flow appears to be more West-East oriented at best. If one looks at the energy from the 500mb low sitting over the Northeast Conus, the energy is quickly lifting up and out with little left other than a lower level surface boundary. Where things get sticky is around 96 hours. Less obvious on the surface maps, is a secondary sharper trough that digs south. Two issues - 1) more dry air pushing southward, and 2) the southwesterly flow though brief, will be fairly strong between 96 - 120 hours. A fairly deep system would seemingly have to be drawn Northeast into such a flow.

Only way I see the 12Z GFS bearing out, is if 93L makes it to over Yucatan (or the W. Caribbean), but then weakens due to land interaction, cooler/dryer air. Hard to imagine this maintaining itself as an identifiable feature to later emerge over the W. Caribbean water and re-intensify though. My guess is that the GFS has it right, right up to the point of W. Yucatan landfall of a named storm, then a weakened depression would traverse SE over land, and perhaps maintain some identity for a couple days before dry air essentially overtakes it.

[gatorcane]

PENN state image of 12Z ECMWF, 144 hours from now just before it makes a turn to the N then NW:

[TheStormExpert]

The 12z Euro solution seems quite possible with it weakening as it heads N/NW out of the W. Caribbean, the GoM has been an unfavorable place for Tropical Cyclones all season (despite the extreme southern BoC), and this late in the season definitely should be no different!

[gatorcane]

18Z BAM guidance and available global guidance (not all are available still on this graphic). Quite a mess to say the least though the TVCN (consensus track) grey line shows a motion east over the Yucatan and a turn to the NE in the NW Caribbean south of Cuba:

[chaser1]

gatorcane wrote:

ECMWF 144 hours has a stronger low south of Cuba and has not merged with the front yet. On the 00Z it was up and away already. Overall the ECMWF is slower and trending closer to the other guidance.

144 hours below:

http://i59.tinypic.com/210djf8.jpg


Yes, 850 vorticity is still stretched out but staying in the NW Caribbean this time instead of Bahamas. I think it gets trapped on this run.

Discussed this possible theory on the discussion thread. There is a scenario down the road where the system could get left behind in the NW Caribbean and get trapped by ridging.

Hmmm, So...., the "Mighty King Euro", bows to the GFS?????? :noteworthy: LOL Hey, I'm not close to buying in, that a hurricane will barrel into South Florida (such as GFS, GEM, or HWRF might suggest), but I did find plausible what NorthJaxPro mentioned earlier in the other discussion thread. Though seemingly unexpected, its not altogether crazy that in spite of the recent long wave pattern AND a sharp trough along the E. Conus.... something just clicks and we have a high pressure ridge in place where "Troughland" previously existed. At least this is what the GFS has been advertising for the last few runs. A bit surprisingly, the EURO has now snapped right in line with regard to the mid level steering flow.

[gatorcane]

12Z GFS ensembles:

[cycloneye]

18z guidance:

[crownweather]

Gotta love the squashed spider look of the models.

18Z BAM guidance and available global guidance (not all are available still on this graphic). Quite a mess to say the least though the TVCN (consensus track) grey line shows a motion east over the Yucatan and a turn to the NE in the NW Caribbean south of Cuba:

[chaser1]

WOW, well "the good news" is that these early ensembles certainly cry "Florida"; All the more reason i'd have to hedge on something at least slightly different ultimately happening.

By the way! While looking at each frame of the new 12Z Euro model, did anyone notice what was developing right along the coast on the Pacific side; perhaps Trudy's little brother???

[MWatkins]

I suppose it's possible the 2nd system in the GFS that spins up at t +120 is this system just hanging around in the western Caribbean, with some vorticity moving out to the east (but the model doesn't have the details down just yet).

If you follow that idea the Euro and GFS aren't too much different in how this evolves by the end of the week.

Could get interesting...

MW

[SFLcane]

This GFS is clearly on to something models now taking 93L in the NW Caribbean Sea.

[cycloneye]

I think we have a consensus among the models now that UKMET completes the 12z package.