ATL: HERMINE - Post-Tropical - Discussion

[gatorcane]

[gatorcane]

maintaining a strong low-level vorticity:

[Blown Away]

Mentions the Bahamas.

A tropical wave located about 1100 miles east of the Lesser Antilles
is producing disorganized showers and a few thunderstorms. The
proximity of this system to dry air 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 be near Hispaniola and
the southeastern Bahamas.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...medium...40 percent

Exactly what we are seeing in the current modeling... The SE Bahamas is where 99L has a chance...

[jason1912]

 https://twitter.com/TropicalTidbits/status/767416033510653953

[HeeBGBz]

The North Gulf Coast usually gets the storms when one goes through the Fla straits or very south Fla. So I watch. Just an opinion not a forecast.

[GeneratorPower]

I am not saying this will be another Katrina. I am interested, however, in Katrina's satellite loop. Watch its sorry, lame formation and tons of dry air surrounding it when it was east of the Bahamas. It only formed when the dry air got moistened. Watch below:



Link: https://youtu.be/wqioiHXzjMo

[chaser1]

"Good get", fascinating to watch that again. Talk about being caught off guard too!

Well just like you, i'm not sayin'.... I'm just sayin'.... lol

[tarheelprogrammer]

Seems as if the spin with 99L has gotten progressively better even without much convection the last 24 hours.

[cycloneye]

I guess recon will be used a lot near Bahamas and beyond.

[JaxGator]

In addition to the good spin, 99L has a lot energy associated with it.

[Blown Away]

JB must have stuck with his original thoughts of a SE CONUS threat.

[tolakram]

live visible

http://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20HURRICANE&lat=15&lon=-40&info=vis&zoom=1&width=1024&height=768&type=Animation&quality=92&palette=ir1.pal&numframes=7&mapcolor=gray

ir

http://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20HURRICANE&lat=15&lon=-40&info=ir&zoom=1&width=1024&height=768&type=Animation&quality=92&palette=ir4.pal&numframes=7&mapcolor=gray

[chaser1]

Seems as if the spin with 99L has gotten progressively better even without much convection the last 24 hours.

I don't think so. I actually thought it looked better during the past day or so. That said however, this is a "big roller" and that large circulation while not deepening in a hurry (especially with present SAL conditions) should begin to tap into some slightly more moist air with SST's warming a tad tomm. and certainly moreso in the days to come. These big systems are slower to just unwind and it would'nt take to many pulls of the rip cord to crank out a small burst of convection perhaps during the next D-max. This should be ample enough to halp maintain a slight surface convergent "status quo" until 55-60W. Here is where I personally think we'll begin seeing some more healthy convection. Keep in mind too, "if" and when conditions improve and we really begin to see some consistant convection or CDO, the point where any deepening might occur will play some role in its own downstream motion and possible impacts. A deeper depression (or T.S.) will likely be a cause for that WNW turn that NHC is anticipating and the timing of which might easily mean a couple degrees or more of northerly latitude - and make a truckload of difference whether 99L hits the shreader over the Islands or possibly just north of the Islands and thus begin an intensification process that the GFS was indicating a couple of days ago.

[colbroe]

As predicted you now see this system wrapping up as it gets closer to 50N,hope it is not an indicator of what will happen down to road,a few hours it was a naked swirl ,to this.

[AutoPenalti]

As predicted you now see this system wrapping up as it gets closer to 50N,hope it is not an indicator of what will happen down to road,a few hours it was a naked swirl ,to this.

Where do you see this?

[colbroe]

I have been watching this wave from the time it became an invest ,this is the best it has looked since it was given the title invest 99L

[Blinhart]

I won't be surprised to see some type of Fujimara (sp)(merging) of Fiona and 99L you can still see that 99L is still stealing some moisture from Fiona. So the timing of this and final location of LLC will have major implications on final motion and strength.

[Weatherboy1]

As predicted you now see this system wrapping up as it gets closer to 50N,hope it is not an indicator of what will happen down to road,a few hours it was a naked swirl ,to this.

Yes, it does appear to be tightening up a bit - even as deep convection is obviously still (mostly) lacking. Will be interesting to see if storms start firing up more overnight and into tomorrow

[chaser1]

I won't be surprised to see some type of Fujimara (sp)(merging) of Fiona and 99L you can still see that 99L is still stealing some moisture from Fiona. So the timing of this and final location of LLC will have major implications on final motion and strength.

Interestingly, I'm pretty sure that one of the global models was indicating just that, on one of its runs a few days back.

[TheAustinMan]

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/