ATL: HERMINE - Post-Tropical - Discussion

[HurricaneFan]

Is it an average of all the models of track and time,combined with the development possibilities of the NHC?

[TheAustinMan]

:uarrow: Is it an average of all the models of track and time,combined with the development possibilities of the NHC?

Information is available in PDF form (though not very detailed) at http://rammb.cira.colostate.edu/realtime_data/nhc/tcgi/tcgi_README.pdf

Here's the important part:

5) What predictors does TCGI use?
[*]TCGI uses a combination of 6 predictors that include Dvorak satellite intensity estimates,
satellite water vapor fields, and model analysis fields;
[*]The individual predictors are described at the bottom of the TCGI real-time output files

The track is usually the GFS' track, but the system may use the BAMM track I think if GFS doesn't continuously indicate the disturbance.

Predictors include, but are not limited to:

CLIM = Climatological Probability of Genesis (Source: NHC-TAFB Invest Database)
HDIV = 850-mb GFS Horizontal Divergence
DV24 = 24-hr Change in GFS 850-mb Vorticity (VORT)
VSHD = 850-200 mb GFS Vertical Shear
MLRH = 600-mb GFS Relative Humidity
PCCD = % GOES WV Pixels Colder Than -40C
TNUM = TAFB T-Number

[SFLcane]

Latest 18z/August 21 Tropical Cyclone Genesis indices for 99L and 90L (with 99L at center). This is an experimental product and should be taken with a grain of salt, but to me it appears to be a fairly decent product.


Source: http://rammb.cira.colostate.edu/realtime_data/nhc/tcgi/

Can you post direct link to this graphic? Thx

[Steve]

Look at the bottom of your quote.

[Steve]

Also for comedy sake, the WPAC has 3 systems in close proximity as well. One moved North then NNE, one moved W then WSW and one is pegged to move N. Interplay is uncanny for 3 systems potentially in the Western Atlantic in a week or so. Key may be the trough lifting out west of Japan.

http://www.ssd.noaa.gov/PS/TROP/Basin_WestPac.html

[SFLcane]

Curious to see what nhc will say in a few min.

[cycloneye]

A tropical wave located about 1000 miles east of the Lesser Antilles
is producing limited and disorganized shower activity. Dry air near
this system is expected to inhibit significant development during
the next few days while the disturbance moves westward to west-
northwestward at 15 to 20 mph. Environmental conditions could
become more conducive for development late this week when the system
is expected to move near Hispaniola and the southeastern and central
Bahamas.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...medium...40 percent

[SFLcane]

Copy and paste there

[floridasun78]

look like their losing hope that good see this as ts soon i hope 99l don't have surprise for us look trying form storm round storm last loop

sts in this forum are NOT official forecast and should not be used as such.

[Steve]

So who knows because it's never possible for the WPAC and WATL to be 100% symmetrical, but I'm looking at

Kompasu = Fiona

Lionrock = 90L/Gaston(?) (look at its size and relative position to the other 2 storms)

Mindulle = 99L/Hermine(?)

The potential difference would be if 99L was to eventually get kicked out west. If so, you'd have to maybe swap Lionrock's wsw bend with Mindulle moving north, I could see that. Notice also the ridging centered over China. If the teleconnection works, There should be ridging in the SEUS/TN Valley next weekend into early the following week. If any of the storms are east of that ridge, they probably get out. Anything south or southeast of the ridge would get stalled or bent more toward the west. Anything on the SW side would get kicked toward the western periphery of the ridge.

This is a cool thing to watch for all amateurs like me because you have some strong parallels now with what is progged out in a week. Unfortunately the joint typhoon warning center site has been down the last several days, but they'll get that fixed. I'm going through WPAC hurricane forecast as linked above in the interim.

[Blown Away]

8pm Update... 99L moving WNW 15-20 mph, that's fast... If you believe GFS, 99L will just be moving away from Bahamas in 12 days... If you believe Euro, 99L will be N of Bahamas/Landfall Daytona in 7 days...

[Bocadude85]

8pm Update... 99L moving WNW 15-20 mph, that's fast... If you believe GFS, 99L will just be moving away from Bahamas in 12 days... If you believe Euro, 99L will be N of Bahamas/Landfall Daytona in 7 days...

My best guess would be something in between the two speed wise. I'm thinking this may recurve prior to Florida but I do think Fiona will play a significant role in the final outcome. My first guess would be recurve and my second guess would be a ts landfall somewhere between Fort Lauderdale and Vero Beach.

[gatorcane]

popcorn convection is back:

[SouthFLTropics]

8pm Update... 99L moving WNW 15-20 mph, that's fast... If you believe GFS, 99L will just be moving away from Bahamas in 12 days... If you believe Euro, 99L will be N of Bahamas/Landfall Daytona in 7 days...

Gimme $500 on the Euro (said in my best Paul Williams/Little Enos voice from "Smokey and the Bandit").

[Blown Away]

From SFWMD and they have direct line to NHC... So 7 days to SFL is more in line with Euro vs 12 with GFS... This was from 11am today...

[AtlanticWind]

popcorn convection is back:

Good, Some extra butter please

[Blown Away]

TAFB... Heading Over PR and just N of Hispaniola in 3-4 days...

[cycloneye]

00z Best Track:

Location: 14.3°N 46.2°W
Maximum Winds: 20 kt Gusts: N/A
Minimum Central Pressure: 1011 mb
Environmental Pressure: 1013 mb
Radius of Circulation: 180 NM
Radius of Maximum Wind: 90 NM

[TheStormExpert]

Latest Morphed Composite.

[GeneratorPower]

Latest Morphed Composite.

Beastly.