ATL: BRET - Remnants - Discussion

[GCANE]

Going just by experience, something tracking this low is likely to be GoM bound.

[wxman57]

If this thing does develop quickly and become a cat 3 (or higher) as some models are indicating, has there ever been a major hurricane that formed so far east in June? I cannot think of any off the top of my head.

Currently, the only model indicating anything close to Cat 3 is the GFS and the models based on it. We've seen how badly it's done in the past. Don't trust it when it's the outlier.

[zzzh]

Looks like a TD. Won't be surprised if NHC pulls the trigger at 00z.

[Sciencerocks]

I'd say if a ascat comes in in next couple of hours showing a closed LLC I'd bet that it will be upgraded within the next 12 hours.

[Craters]

I'm just a weather observer here but can someone explain to me, and I read this all the time, why a stronger storm will get pull towards
the pole and weaker one will continue more westerly?

Thanks

I'll preface this by stating the movement of tropical systems are influenced be a variety of factors (e.g., atmospheric conditions, steering currents, characteristics of the system, etc.). If we just look at the general principles behind the movement of weaker/strong systems:

Weaker tropical systems have a much more shallow convective envelope and have less pronounced/organized circulation patterns (i.e., they have weaker winds and a less defined low-pressure center). As such, these systems feel more of a steering influence from the low-level wind regime (e.g., trade winds), which typically blow from east to west in the tropics. In particular in the deep tropics, these trade winds tend to dominate the steering regime, pushing weaker systems in a more westward direction. As such, weak tropical systems often move with the prevailing easterly winds and net result is a more westward track.

Stronger tropical systems are by nature more organized, presented with a well-defined circulation, stronger winds, and a more pronounced low-pressure center. With a stronger tropical system, we have to look beyond just the low-level steering environment, and we must examine how steering mechanisms change with height/altitude. That is, steering currents that reside higher up in the atmosphere (e.g., the mid-level or upper-level winds), have a greater influence on the movement of well-defined tropical systems. These upper-level winds are often influenced by the overall synoptic weather pattern, (i.e., large scale atmospheric conditions, such as high pressure systems, troughs, or ridges). Stronger tropical systems can "feel" the influence of these larger-scale features more than weaker systems. Consequently, their movement is influenced by the flow around these weather systems, leading to a tendency for stronger systems to turn more poleward or northward.

Thanks, that was very helpful. I sort of guessed that was the reason but I'm not any sort of weather expert so I needed to ask.

Then there's the Coriolis force, which pushes every moving thing in the northern hemisphere to the right of its general motion. This often can be offset by the other steering mechanisms detailed by USTropics, but, without doing a statistical analysis, I'd be willing to say that the major fraction of Atlantic tropical storms/hurricanes end up moving with a fairly large northward component, aided by Coriolis-related effects. There are, of course, exceptions.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sun Jun 18 2023

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

1. Central Tropical Atlantic (AL92):
Showers and thunderstorms continue to become better organized in
association with a broad area of low pressure located several
hundred miles southwest of the Cabo Verde Islands. Environmental
conditions appear conducive for additional development, and a
tropical depression or tropical storm is expected to form over the
next day or so. This system is forecast to move westward at 15 to 20
mph across the central tropical Atlantic with further development
through the middle part of the week. Additional information on this
system, including gale warnings, can be found in High Seas Forecasts
issued by the National Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[chaser1]

A good deal more convection this afternoon but seeming displaced to the north and west of center. I'm still not seeing a well enough defined COC to properly classify this a TD yet. That along with no substantiating evidence to justify otherwise, and lacking any near term threat to land and I just dont see NHC bumping it up quite yet

[GCANE]

In almost all 90/90 cases NRL posts a Tropical Cyclone Formation Alert.
In this case, not yet

[zzzh]

TCFA was issued at 15z.

[Nimbus]

A good deal more convection this afternoon but seeming displaced to the north and west of center. I'm still not seeing a well enough defined COC to properly classify this a TD yet. That along with no substantiating evidence to justify otherwise, and lacking any near term threat to land and I just dont see NHC bumping it up quite yet

Its in a moisture envelope right now but tracking west out in front of the ridge like that there is some shear from the south that might blow the tops off later. I'm seeing the Euro solution making more sense around -45 west we should see the dry air intrusion for the Euro to verify. A better organized storm there would build a stronger moisture envelope and perhaps stall to wait for the GFS weakness.

[GCANE]

GFS now has a big UL anti-cyclone over east Cuba by the time 92L gets to 50W.
What that means?
It'll dive into the east Carib and remain weak.
It'll then get on the SW side of the UL anti-cyclone in the west Carib and then intensify and make a recurve to the NW.
Chances increasing this gets in the GOM.
GOM CAPE values 6000 to 7000 every day for the past week. Record highs.
Been fueling tornado outbreaks from Oklahoma across Dixie Alley.

[wxman57]

GFS now has a big ULL over east Cuba by the time 92L gets to 50W.
What that means?
It'll dive into the east Carib and remain weak.
It'll then get on the SW side of the ULL in the west Carib and then intensify and make a recurve to the NW.
Chances increasing this gets in the GOM.
GOM CAPE values 6000 to 7000 every day for the past week. Record highs.
Been fueling tornado outbreaks from Oklahoma across Dixie Alley.

I think that most likely, the remnant vorticity tracks west into Nicaragua in about 8 days. It then crosses into the East Pac. Don't see a Gulf threat.

[GCANE]

GFS now has a big ULL over east Cuba by the time 92L gets to 50W.
What that means?
It'll dive into the east Carib and remain weak.
It'll then get on the SW side of the ULL in the west Carib and then intensify and make a recurve to the NW.
Chances increasing this gets in the GOM.
GOM CAPE values 6000 to 7000 every day for the past week. Record highs.
Been fueling tornado outbreaks from Oklahoma across Dixie Alley.

I think that most likely, the remnant vorticity tracks west into Nicaragua in about 8 days. It then crosses into the East Pac. Don't see a Gulf threat.

I pray that is true

[cycloneye]

00z Best Track:

AL, 92, 2023061900, , BEST, 0, 104N, 357W, 25, 1010, LO

https://ftp.nhc.noaa.gov/atcf/btk/bal922023.dat

[GCANE]

Still looking like shear-induced convection that fires up and then washes out.
Full on protected pouch IMHO.

[zzzh]

[Hurricane2022]

 https://twitter.com/HurricaneManWx/status/1670602905525657600



Of course that ASCAT would miss the system when we really need an pass.

[Sciencerocks]

[Category5Kaiju]

92L (and the wave trailing it) is relatively small, round, and compact. I feel like if you were to completely remove the map and given me the fact that it is June, then I would have thought that we were looking at the EPAC, not the Atlantic.

[Woofde]

On IR it has that look like it's starting to wrap a bit. Certainly looks like its on its way to being a tc. Outflow also looks improved.