Tropical Storm Bret

[WxWatcher007]

Unsurprisingly, this evening the NHC designated the area of interest in the eastern Atlantic as Invest 92L. 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Fri Jun 16 2023

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

1. Eastern Tropical Atlantic:
A tropical wave located several hundred miles south of the Cabo 
Verde Islands is currently producing a broad area of disorganized 
showers and thunderstorms. Environmental conditions appear conducive 
for additional development, and a tropical depression is likely to 
form by the early to middle portion of next week while the system 
moves westward at 15 to 20 mph across the eastern and central 
tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...70 percent.

Forecaster Papin

 

TC genesis still needs to occur, but thus far this has been a remarkably well forecasted window for development, which @GaWx notes is highly anomalous against the historical record. There are a few reasons why this seems to be a very favorable window for development in the next week. 

First, SSTs are historically warm for this time of year. It's warm throughout the basin, but in the MDR it is particularly hot. 

Much higher than normal SSTs have allowed the MDR to be conducive at least thermodynamically. 

 

Why? In large part because of the mid/upper level pattern we haven't seen strong trade winds, or SAL, to temper warming in the MDR east of the Antilles. 

Just as important, we see a highly anomalous amount of OHC throughout the basin. This is a gif I quickly put together showing OHC values from 2016-2023 in mid June. 

And today's value as a single image:

This is only one piece of the puzzle, however. In this region we also have reduced shear, and higher moisture levels, critical elements in TC development and survival that are usually hostile this time of year. It's about as good as it gets, currently. 

Here's the 12z EPS using 5 day averaged wind shear anomalies. This is an incredible look that has trended more favorable in recent days.

Just as impressive is the moisture envelope. In recent years, dry air and stability put a cap on TC genesis and development, especially in the central and eastern MDR. That does not appear to be an issue this time, which again, is extremely impressive for mid-June. 

Coupled with the passage of a CCKW, and this all leads to a highly favorable environment IMO for TC genesis. This would be a highly favorable environment in September. 

 

It doesn't look like much now, but ASCAT shows that while elongated, it is trying to gradually consolidate. I think it will, and from there it'll be a question of

1) how quickly 92L can take advantage of the favorable environment, and
2) what the longer range steering pattern evolves into 

There's not much more to say yet, other than the operational guidance has become more bullish on intensification in the last 24 hours for the above reasons. 

As for track, while both ensembles (EPS/GEFS) look to favor an eventual recurve, it is extremely early to look long range on steering, though climo almost always favors a recurve, especially in the current upper level regime.

I would watch closely in the Antilles. 

 

[thunderbolt]

I smell a fish

[Ed, snow and hurricane fan]

11 hours ago, thunderbolt said:

I smell a fish

The GFS and ECMWF ensemble mean is into or just N of the Lesser Antilles.  I'd bet money on the fish as well (TVCN consensus is a fish), but it isn't a lock.  The stronger members tend to recurve.

[Ed, snow and hurricane fan]

On Euro, 92L stays weak enough to make it to the LA.  Dry air and shear are the picadors, Hispaniola is the matador.

 

[NeffsvilleWx]

I don't trust the euro output.

It's got a 102x mb high parked right over venezuela for the entire model period that really just doesn't really move save for a few spurious changes (including 1 panel at hr 69 where it changes to a 1007 mb low before changing back to 102x high on the next panel). Looks to be right over Pico Cristobol Colon.

I'd think if it were accurate, there'd be a little bit of panel to panel wobble to that high. Or maybe I'm just an idiot. That's certainly possible.

 

[Ed, snow and hurricane fan]

28 minutes ago, NeffsvilleWx said:

I don't trust the euro output.

It's got a 102x mb high parked right over venezuela for the entire model period that really just doesn't really move save for a few spurious changes (including 1 panel at hr 69 where it changes to a 1007 mb low before changing back to 102x high on the next panel). Looks to be right over Pico Cristobol Colon.

I'd think if it were accurate, there'd be a little bit of panel to panel wobble to that high. Or maybe I'm just an idiot. That's certainly possible.

 

Pretty sure that is an artifact of Tropical Tidbits display, not the Euro.  If the model had a 1024 high, exceptionally high for the deep tropics, the winds around that H would reflect it.

[Stormchaserchuck1]

Early season storms are more likely to track W->E

20N/60W is a huge point difference to pass north or south of. 70/30 vs 10/90 or something. 

[tiger_deF]

We're on the cusp

[WxWatcher007]

Yeah, certainly looks like an organizational trend the last 12 hours.

[Superstorm93]

Shallow but consistent convection has really done its job to help organize the circulation. 

I'd imagine this is a depression by early Monday

[Ed, snow and hurricane fan]

Most GFS ensembles are a 'fish', because most are strong, most Euro ensembles are into the Caribbean, because most are weak.  I think strength determines path, but the Lesser Antilles are in decent shape either way, a miss or a weak system.  Hispaniola might have flood issues with a weaker system just because it reaches them.  GFS and Euro shear and moisture currently looking favorable.  Satellite makes me thing it won't close off immediately, but when it does, it could intensify quickly.  Or either the GFS family stronger and recurve or the Euro family weaker and make it to the LA seem reasonable.

[GaWx]

Up to 90%/90% in 2PM EDT TWO:

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.

Forecaster Blake

[WxWatcher007]

Pretty consistent convection tonight with a robust mid level circulation (at least). Hard to tell if there’s a LLC under there.

[WxWatcher007]

Well, morning visible imagery shows that 92L has organized considerably overnight, and is on the cusp of becoming a tropical cyclone. It may very well be a close call for the Antilles as both the Euro and GFS have modest intensification before a close pass/hit.

[Drummer]

Here we go.

.

[WxWatcher007]

We’re about to find out the NHC’s first thoughts on track and intensity.

If I were to hazard a guess, I’d say the first forecast would bring it to the northern Lesser Antilles as a 65kt system. 

[WxWatcher007]

Tropical Depression Three Discussion Number   1
NWS National Hurricane Center Miami FL       AL032023
1100 AM AST Mon Jun 19 2023

Satellite images indicate that the tropical wave over the central 
Atlantic has become better organized this morning.  GOES-16 1-min 
visible imagery shows that the center has become well defined near 
a developing central dense overcast with prominent convective 
banding in the northern semicircle.  The initial intensity is set to 
30 kt, based on Dvorak estimates from SAB and TAFB, and recent 
satellite trends indicate this system is close to tropical-storm 
status.

The initial motion estimate is 275/18 kt, a bit uncertain because 
the center has just recently become trackable.  A large ridge of 
high pressure over the central Atlantic Ocean is forecast to cause 
the depression to move westward over the next several days. As the 
system nears the Lesser Antilles late this week, the ridge should 
weaken, causing the system to move more toward the west-northwest.  
However, there is considerable uncertainty in how much of a right 
turn could occur because it is somewhat tied to the intensity of the 
cyclone.  A stronger system would tend to move more to the right due 
to the upper-level flow, while a weaker system would continue more 
westward into the Caribbean.  For now, this forecast lies near the 
model consensus, and adjustments are likely in future advisories.  
This should be considered a low confidence track forecast since 
this type of forecast situation can result in large errors.

Environmental conditions appear conducive for strengthening over 
the next few days, with a much warmer than normal ocean in the 
depression's path, along with plentiful mid-level moisture and 
light shear.  This should promote strengthening through midweek.  
However, vertical wind shear is forecast to increase by most of the 
model guidance around day 3 in response to an upper-level trough.  
Thus the NHC forecast shows the intensity leveling off at the end 
of the forecast, consistent with the middle of the guidance 
envelope.  This intensity forecast is also more uncertain than 
normal, due to the differences in the model suite, along with the 
aclimatological nature of this system. 

KEY MESSAGES:

1. The depression is forecast to strengthen and move across the 
Lesser Antilles as a hurricane on Thursday and Friday, bringing a 
risk of flooding from heavy rainfall, hurricane-force winds, and 
dangerous storm surge and waves. 

2. Given the larger than usual uncertainty in the track forecast, 
it is too early to specify the location and magnitude of where 
these hazards could occur. However, everyone in the Lesser 
Antilles, Puerto Rico, and the Virgin Islands should closely monitor 
updates to the forecast for this system and have their hurricane 
plan in place. 



FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 11.0N  40.3W   30 KT  35 MPH
 12H  20/0000Z 11.2N  42.9W   40 KT  45 MPH
 24H  20/1200Z 11.7N  45.9W   45 KT  50 MPH
 36H  21/0000Z 12.2N  48.6W   55 KT  65 MPH
 48H  21/1200Z 12.8N  51.2W   60 KT  70 MPH
 60H  22/0000Z 13.3N  53.9W   65 KT  75 MPH
 72H  22/1200Z 13.8N  56.3W   70 KT  80 MPH
 96H  23/1200Z 14.9N  61.5W   70 KT  80 MPH
120H  24/1200Z 16.5N  66.5W   65 KT  75 MPH

$$
Forecaster Blake/Kelly

[WxWatcher007]

Hmm. The long range shear forecast is critical for intensity, and possible track. 

[MJO812]

1 hour ago, WxWatcher007 said:

Hmm. The long range shear forecast is critical for intensity, and possible track. 

Gfs is already shifting more west 

[WxWatcher007]

Pretty divergent solutions still on track and intensity. Looking at TD 3 though, it’s continuing to organize at a modest pace. 

[BYG Jacob]

Hi Bret

[WxWatcher007]

Should be there at 5pm 

[cptcatz]

Structure looks nice but all models have it go poof as soon as it enters the Caribbean. If the NHC is right and it maintains at a 75-80 mph hurricane through the Caribbean, they would get mad respect. 

[GaWx]

1 hour ago, WxWatcher007 said:

Should be there at 5pm 

It appears that it will be upgraded at 5PM EDT per this:

AL, 03, 2023061918, , BEST, 0, 112N, 414W, 35, 1008, TS

 This would tie it with Bret of 2017 as the earliest TS in the MDR east of the Caribbean on record back to 1851.

[WxWatcher007]

30 minutes ago, cptcatz said:

Structure looks nice but all models have it go poof as soon as it enters the Caribbean. If the NHC is right and it maintains at a 75-80 mph hurricane through the Caribbean, they would get mad respect. 

It’s an aggressive opening bid, particularly for the Caribbean portion. I thought it would make it to the islands as a minimal cane, but get blown to bits by shear afterward.

That said, we have numerous examples of TCs in this basin recently that were either resilient in the face of shear due to sound structure, or exceeded initial expectations to an extent because of shear intensity/vector forecasts missing. 

Hopefully with a well defined LLC now we can get some kind of convergence on guidance in subsequent suites. 

[CarbondaleWX]

https://twitter.com/NHC_Atlantic/status/1670895245998067722

[Floydbuster]

I remember Claudette in early July of 2003. Developed into a strong TS/minimal Cat 1, quickly died in the Eastern and Central Caribbean, but found it's way back in the Western Caribbean and Gulf of Mexico and struck Texas as a 90 mph hurricane.

I always am wary of systems like Bret because even if it "dies" in the Eastern Caribbean, that doesn't preclude it returning and striking land further west as a stronger system down the road.

[WxWatcher007]

I don’t think it’ll get that far west, but I was saying in the Mid-Atlantic thread that I like Elsa as an early analog. I think there will be shear, but the euro is too aggressive tearing it apart and driving it due west into the Caribbean. IMO.

[Floydbuster]

2 minutes ago, WxWatcher007 said:

I don’t think it’ll get that far west, but I was saying in the Mid-Atlantic thread that I like Elsa as an early analog. I think there will be shear, but the euro is too aggressive tearing it apart and driving it due west into the Caribbean. IMO.

I'm actually quite surprised at how favorable things look ahead compared to other early systems. It's not ideal but far from complete obliteration like Danny 2015.

[WxWatcher007]

21 minutes ago, Floydbuster said:

I'm actually quite surprised at how favorable things look ahead compared to other early systems. It's not ideal but far from complete obliteration like Danny 2015.

I really am starting to think the MDR being open like this may be an early signal of a more active season. It’s not just that much of the basin is historically warm…the TUTT is displaced northward and with this early wave train we are seeing no issues with stability and SAL like past years. 

To get one TC is historic for this time of year, the guidance is trending toward multiple TC genesis opportunities in the next 10-14 days.