ATL: ISAAC - Post-Tropical - Discussion

[Craters]

I am curious, if Isaac becomes something in the future, would he still be Isaac or would he be Kirk?

On the basis of past experience (hopefully remembered correctly!) Isaac would still be Isaac. My guess at the reasoning would go like this: a named storm hits a small but intense "unfavorable environment," loses its closed circulation, and its winds drop to 30 kt for just a short time, say 8 hours. Then it reorganizes. No need to change its name just because of a hiccup.

Granted, Isaac lost its status and name quite a while ago, but with all of the resources available these days, its remnants can't hide, even if it doesn't want to go on the cart...

Almost forgot -- if a storm's remnants cross, say, from the Caribbean to the EPAC and reorganize there, it would get the next name in line for the EPAC. (Somebody please correct me if that's wrong.)

[EquusStorm]

If a storm totally dissipates and its disheveled remnants with no continuation of surface low reorganize in the Epac, it gets the next Epac name (Katia-Otis 2017) and is considered a separate storm; current policy is, if it survives as a coherent circulation it keeps the name (Otto 2016) though this has only happened a handful of times and only once since it was changed. Before I think 2000, the policy was to change the name when crossing basins no matter how organized it was even if it survived (Cesar-Douglas for example) Otto 2016 is the only time that's happened since that policy change and thus the only one ever to keep its name when crossing

[SoupBone]

No model support whatsoever at this point.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Sep 17 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Depression Joyce, located a few hundred miles south of the Azores.
The NOAA Weather Prediction Center has issued the last advisory on
Post-Tropical Cyclone Florence, located inland over the central
Appalachian mountains.

1. Disorganized showers and a few thunderstorms extending from Jamaica
and eastern Cuba westward for a few hundred miles across the
northwestern Caribbean Sea are associated with the remnants of
Isaac. Environmental conditions are expected to remain unfavorable
for re-development while the system moves west-northwestward to
westward across the northwestern Caribbean Sea. Even though
development is unlikely, brief periods of locally heavy rainfall and
gusty winds are possible over portions of Jamaica, as well as
eastern and central Cuba, during the next couple of days.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...near 0 percent.

[Audreyadele]

I’ve been trying to find the Harvey Discussion from last year and haven’t had any luck. Is that not possible? From my understanding, Harvey and Isaac had similar beginnings with very different outcomes. For me, it would be very helpful to compare the discussions to understand the why.

Side note: I stumbled upon this site last summer when Harvey wasn’t Harvey and from my understanding he was just a wave. I had no clue about the models y’all were referring to and thought it was crazy that a google search for “Port Mansfield, TX Hurricanes” led me to Storm2K when Harvey wasn’t at all Harvey! I believe it was page 9 or 10 on an invest at that point. I googled that because my husband was trying to tell me that Port Mansfield, TX is not susceptible to hurricanes because of the Laguna Madre. He built a fishing camp there and all his uncles said they were safe. His uncle’s house survived Allen in 1980 and that became the precedent. Now, I’m watching the news on Florence and after experiencing Harvey I’m still amazed I sometimes have to still argue with my husband that Port Mansfield does not have a hurricane shield. Although, he does ask me now (and has been since Harvey) what “my storm tracker people” are saying.
Thank you for your posts. All of you might not think of it this way, but your knowledge and willingness to share it are saving lives. So, wanted to say Thank you!

[tailgater]

Someone please explain why this system isn’t redeveloping, just curious because with my very limited skills I don’t see why it isn’t? Maybe it’s substance, a little dry air or is it some other factor I don’t see?
I hate just going by what the models say, I’ve been around long enough to know they are usually right but I still enjoy trying to figure out what will happen from looking at satellites and other data maps.

[SconnieCane]

My guess would be lack of synoptic scale upward motion. It can pulse convection but can't seem to sustain it, much like 95L before it. I've heard rumblings of the MJO returning to a favorable state over the Atlantic basin in a week or two, perhaps when that occurs any waves that can evade the SAL gauntlet will have better luck.

[bbadon]

Someone please explain why this system isn’t redeveloping, just curious because with my very limited skills I don’t see why it isn’t? Maybe it’s substance, a little dry air or is it some other factor I don’t see?
I hate just going by what the models say, I’ve been around long enough to know they are usually right but I still enjoy trying to figure out what will happen from looking at satellites and other data maps.

I'm wondering the same thing. It sure looks like its making another go at it to me. (According to visible sat)

[wxman57]

Someone please explain why this system isn’t redeveloping, just curious because with my very limited skills I don’t see why it isn’t? Maybe it’s substance, a little dry air or is it some other factor I don’t see?
I hate just going by what the models say, I’ve been around long enough to know they are usually right but I still enjoy trying to figure out what will happen from looking at satellites and other data maps.

I'm wondering the same thing. It sure looks like its making another go at it to me. (According to visible sat)

I'm not seeing anything to be concerned about in the visible satellite loop. Just a couple of thunderstorms moving through the NW Caribbean. Pressures are relatively high. TPW (moisture) is a bit low. No model support at all - less than with 95L last week, and 95L was a lot stronger of a wave (which didn't develop anything but a very weak low).

[tolakram]

I’ve been trying to find the Harvey Discussion from last year and haven’t had any luck. Is that not possible? ...

Hi Audrey,

You can find archived threads off the Talkin Tropics forum, Storm Archives.

viewforum.php?f=54

Harvey is in the 2017 folder, right here: viewtopic.php?f=85&t=118961

[Hammy]

I'm amazed there's still a closed circulation at the moment. Is the lack of moisture the primary block for regeneration?

[EquusStorm]

Part of me wonders if it can survive its trip across Mexico/Central America and emerge as a coherent wave in the Epac to slowly reorganize. Doubt it, but could be an interesting legacy.

[EasyTiger]

The environment is starting to look more "tropical" again surrounding the remnants of Isaac. Sleeping with one eye open...

[lrak]

I know no model support but the northern remnants of Issac look to be moving into the S. GOM soon. It appears to be moving NW or WNW. What's stopping it from developing? Sure looks good on visible satellite.

[Audreyadele]

I had to have some basic understanding, which I didn't.

I looked up what the NHC said today and zeroed in on 3 things...

1. Upper Level Low
2. Upper Level Diffluence
3. High Pressure

Yes, I know these are the basics, but I have to start somewhere.

Anyways, I started with High Pressure and that basically solved the mystery... I think. Then, I looked up Upper Level Low and Upper Level Diffluence and I'm thinking these would be the "factors" that could possibly change the forecast. I'm assuming this is why the NHC included them in their report.
I read more about diffluence than Upper Level Low because Convergence, Divergence and Diffluence all required some serious brain power to understand their basic differences. I'll go back to Upper Level Low soon, but for some reason my brief research led me to want to read more about diffluence.

Now, how the upper level low over South Texas and the upper level diffluence over the western gulf could possible change the forecast... I have not gotten their yet and going to rely on the experts.
I just want to know if I'm reading the report correctly. Opinions, corrections, thoughts or any advice on where to keep looking, classes/workshops etc I'm all ears.

057
AXNT20 KNHC 200005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Wed Sep 19 2018

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2330 UTC.

...DISCUSSION...

GULF OF MEXICO...

The northern extent of a surface trough, the remnants of Isaac,
is over the Yucatan Peninsula. Scattered moderate convection is
over the Yucatan Channel and the eastern Yucatan Peninsula. Weak
surface ridging is over the remainder of the Gulf of Mexico with
axis along 28N.

In the upper levels an upper level low is centered over S Texas
near 28N98W. Upper level diffluence is over the W Gulf. Scattered
showers are from 20N-25N between 95W-98W. The remainder of the
Gulf has mostly fair weather.

High pressure will build over the eastern United
States through tonight, allowing gentle to moderate E to SE
breezes and 2 to 4 ft seas across the Gulf through Sun. A trough
over the northwest Caribbean and Yucatan Channel will shift
westward across the south central Gulf and Yucatan Peninsula
through tonight, and across the southwest Gulf Thu and Fri, before
dissipating Sat.

[lrak]

Hi Audrey,

I have been watching weather since "Athletics" back in grammar school. "Watching the weather" lol no internet back then except for gubberments.

I only have a basic understanding of the weather and rely on these peeps to set me straight. Oh and welcome to the forums, this is the best bunch you'll get for learning about the weather. So many variables, that's why most professional meteorologist will only bank on data about 2-3 days out is what I've learned. Have fun here and learn a new hobby

By the way Isaac is a poor naked swirl this morning.

[gfsperpendicular]

Hi Audrey,

I have been watching weather since "Athletics" back in grammar school. "Watching the weather" lol no internet back then except for gubberments.

I only have a basic understanding of the weather and rely on these peeps to set me straight. Oh and welcome to the forums, this is the best bunch you'll get for learning about the weather. So many variables, that's why most professional meteorologist will only bank on data about 2-3 days out is what I've learned. Have fun here and learn a new hobby

By the way Isaac is a poor naked swirl this morning.

How does he still have a swirl?! Interesting...