ATL: ERIKA - Remnants - Discussion

[NDG]

Everybody is acting surprised that the LLC is clearly seen now separated from the MLC but the HWRF has been showing this for a number of runs now.
It shows not to start getting better vertically stacked not until it gets north of Mona's Pass.

[Hammy]

I have never seen such discrepancies in posts in the 11 years I have been on here. One saying it will fish, one saying it won't. One saying it has decoupled one saying not. One saying it is firing back up and one saying it is dying down. I think I need to take a break and go and get some water.

Make sure you water Erika, it's looking a bit dry on the western side

In
fact, Erika could degenerate into a trough of low pressure due to
the shear and interaction with the Greater Antilles.

Latest NHC discussion leaving open the possibility of degeneration in the short term prior to restrengthening, possibly so people don't let their guard down should it occur.

Edit: Erika's pressure is dropping, how is this happening with the circulation getting farther from the convection?

[gatorcane]

New track:

[NDG]

New track is very similar to the 12z GFS run.

[SFLcane]

Nice shift...

[ img]http://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL0515W5_NL+gif/205325W5_NL_sm.gif[/img]

[SouthFLTropics]

INIT 26/2100Z 16.6N 58.9W 40 KT 45 MPH
12H 27/0600Z 17.1N 61.2W 40 KT 45 MPH
24H 27/1800Z 18.1N 64.0W 40 KT 45 MPH
36H 28/0600Z 19.2N 66.8W 40 KT 45 MPH
48H 28/1800Z 20.5N 69.6W 40 KT 45 MPH
72H 29/1800Z 22.7N 74.3W 40 KT 45 MPH
96H 30/1800Z 25.0N 77.7W 55 KT 65 MPH
120H 31/1800Z 27.5N 80.0W 65 KT 75 MPH

New NHC forecast still tops out at 75mph

Looks to be nudged a hair NE at the final point. Almost had to due to the shift in the 12z models. I'm very curious to see if the 18z GFS trends further east.

SFT

[ozonepete]

Regarding shear, the tendency map here shows that Erika is actually going from an area of higher shear to an area of somewhat lower shear. If you use the "-3 hours" feature and go back 12-18 hours, you see she is in an area of brighter yellows/oranges. Now, she's entering a more green/light yellow zone. Would seem to me she's poised to enter a more favorable shear zone by tomorrow morning, assuming she holds together until then no? Or am I reading this wrong?

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

Semi-educated amateur ... listen to the experts as always!

The one thing you're reading wrong is that that is a current status of shear and not a forecast. Now since shear in the tropics almost never changes really quickly (faster than 6 hours time period) you can assume that Erika is indeed moving into an are of less shear overnight. But when you are talking 12 hours or more ahead, now you need to look at the shear forecast. So you cant use that chart to say what the shear will be like from tomorrow morning onward. For that you need a shear forecast chart.

[ozonepete]

New track is very similar to the 12z GFS run.

Starting to look like a recurve. Like Floyd.

[SFLcane]

All of the models have shifted eastward at days
four and five, but the normally reliable GFS and ECMWF define
the western edge of the guidance. Out of respect of
these models and the previous NHC forecast, the updated track
has only been moved slightly eastward late in the period. As a
result, the new forecast lies west of the multi-model consensus at
96 and 120 h. One should remember to not focus on the exact forecast
track, especially at the long range where the average NHC track
errors during the past 5 years are about 180 miles at day 4 and 240
miles at day 5.

[SouthFLTropics]

New track:

Good analog would be Erin 1995

[tgenius]

INIT 26/2100Z 16.6N 58.9W 40 KT 45 MPH
12H 27/0600Z 17.1N 61.2W 40 KT 45 MPH
24H 27/1800Z 18.1N 64.0W 40 KT 45 MPH
36H 28/0600Z 19.2N 66.8W 40 KT 45 MPH
48H 28/1800Z 20.5N 69.6W 40 KT 45 MPH
72H 29/1800Z 22.7N 74.3W 40 KT 45 MPH
96H 30/1800Z 25.0N 77.7W 55 KT 65 MPH
120H 31/1800Z 27.5N 80.0W 65 KT 75 MPH

New NHC forecast still tops out at 75mph

Looks to be nudged a hair NE at the final point. Almost had to due to the shift in the 12z models. I'm very curious to see if the 18z GFS trends further east.

SFT

It appears (of course subject to change) to keep inching up.. if 18z GFS and subsequent runs keep pointing east then SFLA may avoid the brunt of it (but will probably get some nasty rain out of it)

[Bocadude85]

New track is very similar to the 12z GFS run.

Really isn't much different then the 12z Euro either.

[tolakram]

You can view the GFS shear forecast on this page: http://moe.met.fsu.edu/tcgengifs/

For the GFS model run select 850-200mb shear and submit.

http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?time=2015082612&field=850-200mb+Shear&hour=Animation

You can do something very similar on TropicalTidbits.

http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=shear&runtime=2015082612&fh=6&xpos=0&ypos=535

[Evil Jeremy]

New track is very similar to the 12z GFS run.

Really isn't much different then the 12z Euro either.

Creates a tricky situation... Do you go with the two most successful models agreeing with each other, or all the other (outnumbering) models showing option B?

[NDG]

I get the feeling the NHC will not go with the 18z tropical model guidance concensus unless the GFS & Euro shift eastward on their next run, lets remember that most tropical model guidances were right biased with Danny.

All of the models have shifted eastward at days
four and five, but the normally reliable GFS and ECMWF define
the western edge of the guidance. Out of respect of
these models and the previous NHC forecast, the updated track
has only been moved slightly eastward late in the period.

[hurricanedude]

ozone pete..Floyd was horrible for north carolina and virginia....i assume that these two states are in the cards as well as florida?

[SouthFLTropics]

Something else to consider...I know it's been 11 years since Frances but take a look at the track then...forecast for a Jax landfall and then tracked back South and the rest is history. I'd be willing to bet the models will oscillate back and forth for the next day or so...

[Hammy]

Recon found a wind shift well SW of the previous fix, showing that Erika is still closed, albeit barely, but also probably has multiple "centers" rotating around.

[NDG]

Recon found a wind shift well SW of the previous fix, showing that Erika is still closed, albeit barely, but also probably has multiple "centers" rotating around.

Thanks for the info, it also clearly seen on vis satellite that Erika has a vigorous large surface circulation, unlike Danny when was in this area.

[ozonepete]

ozone pete..Floyd was horrible for north carolina and virginia....i assume that these two states are in the cards as well as florida?

Yes, I'm aware of that. And a really close call for Florida. And I was only referring to track. As far as the Carolinas and north, they are only in play because there is no reliable way to forecast past 5 days. Now the first very slight indications right now are for it to go out to sea if it does recurve east of Florida. But once again it's way too early. I would just keep a close eye and trust the forecasts a lot more when we get within 3 days of landfall.