ATL: BRET - Remnants - Discussion

[Category5Kaiju]

That crescent-shaped banding of 92L kind of reminds me of Sam 2021 during that storm's primitive stages.

[cycloneye]

90%/90%

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

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

Eastern Tropical Atlantic (AL92):
Showers and thunderstorms have 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.

&&

High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFAT1, WMO header FZNT01
KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php

$$
Forecaster Blake

[AtlanticWind]

Bold Prediction…still another 48-72 hrs before TCG from 92L. Convection will wain tonight and 92L will be a shell of what it was by morning…it will struggle all Sunday into Sunday night producing any convection, and will start to come back Monday. Will probably see designation Tuesday. This is given past experience with these early season systems.

Not too bold. I'm issuing our first 7-day track now. Have it reaching TD at 48 hrs (Tuesday AM) and 35 kts Tuesday night. Peaks 45 kts Thursday then weakens to 35 kts as it passes Guadeloupe Friday morning and a remnant low south of PR over the weekend. I totally ignored the GFS.

That seems a little conservative to me looking at the intensity models
I think 60 to 70 knots based on modeling seems likely.
Just an amateur opinion though

[Hammy]

Bold Prediction…still another 48-72 hrs before TCG from 92L. Convection will wain tonight and 92L will be a shell of what it was by morning…it will struggle all Sunday into Sunday night producing any convection, and will start to come back Monday. Will probably see designation Tuesday. This is given past experience with these early season systems.

Not too bold. I'm issuing our first 7-day track now. Have it reaching TD at 48 hrs (Tuesday AM) and 35 kts Tuesday night. Peaks 45 kts Thursday then weakens to 35 kts as it passes Guadeloupe Friday morning and a remnant low south of PR over the weekend. I totally ignored the GFS.

That seems a little conservative to me looking at the intensity models
I think 60 to 70 knots based on modeling seems likely.
Just an amateur opinion though

Most of the hurricane-centered models drastically overintensity, especially in absence of recon data, and had a mid-range tropical storm by now.

[wxman57]

Now I'm thinking a little earlier arrival in east Caribbean - Thursday evening. Could peak at 35 kts before then, but it may be weakening to a TD or even a remnant low when it reaches the Caribbean. I do not trust the GFS at all, so don't pay much attention to its favorable upper-air environment. It could make it to TS Bret in a couple days, but it will likely be weakening by Thursday morning. Not much impact at all in the islands. 12Z EC may be pretty good, though it may still be too slow

[cycloneye]

18z Best Track:

AL, 92, 2023061818, , BEST, 0, 97N, 340W, 25, 1010, LO

[JetFuel_SE]

Now I'm thinking a little earlier arrival in east Caribbean - Thursday evening. Could peak at 35 kts before then, but it may be weakening to a TD or even a remnant low when it reaches the Caribbean. I do not trust the GFS at all, so don't pay much attention to its favorable upper-air environment. It could make it to TS Bret in a couple days, but it will likely be weakening by Thursday morning. Not much impact at all in the islands. 12Z EC may be pretty good, though it may still be too slow

The Euro sucks with developing systems, and almost always underestimates them. I'd say you're putting way too much weight on it.

[wxman57]

Now I'm thinking a little earlier arrival in east Caribbean - Thursday evening. Could peak at 35 kts before then, but it may be weakening to a TD or even a remnant low when it reaches the Caribbean. I do not trust the GFS at all, so don't pay much attention to its favorable upper-air environment. It could make it to TS Bret in a couple days, but it will likely be weakening by Thursday morning. Not much impact at all in the islands. 12Z EC may be pretty good, though it may still be too slow

The Euro sucks with developing systems, and almost always underestimates them. I'd say you're putting way too much weight on it.

In this case, I don't think so. The environment in its path is not very favorable (ignoring the GFS). Lots of dry air ahead of it and behind it. Could see it (the SAL) on the morning visible shot. I think it will struggle to maintain convection, but the NHC will probably call it Bret on Tuesday. Should peak Wednesday morning then weaken.

[chaser1]

Looks like we're beginning to see a couple towers building over center.

[USTropics]

The Euro trended stronger overnight so you might be on a bit of the bearish side. 65-75 kt seems like a good range IMO, since models seem to agree with a 995-980 range it seems. We’ll see.

If it's stronger, then it won't reach the NE Caribbean, it'll turn north like the GFS.

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.

[Yellow Evan]

GFS has the environment that would support a system of substantial intensity given the high SST's, ideal upper level conditions, and about 10 knots of mid level shear (not perfect for a strong hurricane but manageable). ECMWF's upper environment at least as of 6z would favor a sheared tropical storm because easterly mid-level flow is much faster. Answer as usual probably lies somewhere in between but I definitely think the 12z ECMWF is developing this too slowly in the next 24-36 hours given recent satellite trends.

[cycloneye]

Tropical tidbits site has 92L now in the MESO section. Convection is increasing but the most important thing is to have a well defined circulation. I guess DMAX will cause a boost contrary to last night.

https://www.tropicaltidbits.com/sat/

[cycloneye]

Video by Levi.

 https://twitter.com/TropicalTidbits/status/1670525750984998912

[Sciencerocks]

[aspen]

https://imagizer.imageshack.com/img923/3853/uUekcR.gif

I’m on mobile so I can’t post an image, but the latest 850mb vorticity map from CIMSS shows that, while still a little oblong, the vorticity signature for 92L is concentrated roughly where that big convective burst is occurring (~11N/35W). This DMAX could be enough to further concentrate the system and push it to TC status.

[hipshot]

If it's stronger, then it won't reach the NE Caribbean, it'll turn north like the GFS.

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.

[Hybridstorm_November2001]

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.

[cycloneye]

 https://twitter.com/Yellow_Evan/status/1670531186077343744




 https://twitter.com/Yellow_Evan/status/1670531194931535873

[Category5Kaiju]

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.

No, never at least in recorded history. June has had 2 major hurricanes in recorded history from what I understand: Audrey in 1957 and Alma in 1966. Bother were in the Gulf of Mexico though. Hence why if, for whatever reason 92L ends up defying expectations and becoming a major hurricane, that would be exceptional and pretty much unprecedented.

[Category5Kaiju]

 https://twitter.com/VegaBajaWx/status/1670533143172984832




Oh snap, it's close