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2024 Atlantic Hurricane Season

First NHC forecast cone on TD2.
203520_5day_cone_no_line_and_wind.png
 
wx_guy said:
Point taken, but the designation difference between a TD/TS and Invest 95L is basically zero at this point. The models have been running for Invests for several seasons now, and while they weren't designed with Invests in mind, the models do a decent job predicting even at the Invest level.
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@wx_guy I have not personally seen this in recent years. Do you have some evidence to back this up?
wx_guy said:
Yes, SHIPS uses the GFS for some of its variables, but it also uses satellite data and other data sources besides the GFS. There's waaaaay too much hate in the amateur wx community on the GFS -- it is still consistently a great model most of the time in the short and medium range, slightly sub-par to the Euro.
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The GFS, if anything, has done worse with intensity in the short to medium term since its “upgrade” some years ago.
wx_guy said:
But so much of our existing infrastructure is GFS-derived, including the HAFS-A and HAFS-B and the GEFS and parts of the SHIPS model. So lamenting about the GFS does us not much good, because a large part of our forecasting suite is reliant upon it. You might as well say "Don't trust the modeling ever", which is not useful.
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The problem is that people have, in my view, come to rely excessively on models and have neglected the lost art of forecasting. Forecasting involves the ability to recognise biases and patterns, thereby accounting for the deficiencies of modelling.

Anyway, the 12Z GEFS has trended sharply toward the EPS vs. 00Z. Many 00Z members showed a fairly robust hurricane impacting the Lesser Antilles. Many fewer 12Z members do so, and the ones that do are notably weaker. The mean is much farther southwest as well, hence faster.

Needless to say, I do not agree with the NHC’s call for a Cat-2 in three to four days. At all. Especially when the more-reliable EPS indicates a tropical storm at most during this timeframe, while the GEFS is likely starting to shift rather dramatically toward the EPS in all respects. I really can’t see more than a middling TS right now...
 
NHC is watching both the current system in the Caribbean Sea and the wave behind TD2 for some possible limited development in the longer term.
1. Northwestern Caribbean/Southwestern Gulf of Mexico (AL94):
A broad area of low pressure over the northwestern Caribbean Sea
continues to produce widespread but disorganized shower and
thunderstorm activity. Development of this low is not anticipated
before it moves inland over the Yucatan Peninsula on Saturday. The
system is then forecast to move west-northwestward, emerging over
the Bay of Campeche Saturday night or early Sunday, where conditions
appear generally conducive for further development. A tropical
depression could form before the system moves inland again early
next week over Mexico. Regardless of development, heavy rainfall
associated with the area of low pressure will affect portions of
Central America and Mexico through early next week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...40 percent.

2. Eastern Tropical Atlantic:
A tropical wave located several hundred miles south-southwest of the
Cabo Verde Islands is producing an area of disorganized showers and
thunderstorms. Environmental conditions appear generally conducive
for additional development of this system, and a tropical depression
could form by the middle of next week while it moves generally
westward at 15 to 20 mph across the eastern and central tropical
Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.
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1719619250058.png
 
If the ADT is correct (or if the NHC takes it on board), we should have a Tropical Storm Beryl at 11 PM. 34 knots is TS-force. 1719621657903.png
 
Officially Beryl, according to the latest SHIPS. At 55%, it is essentially explicitly forecasting a 65kt growth in 72 hours, to around 100 knots (about 110 mph). Still looking potent at 5-6 days out, assuming it avoids major land masses.

EDIT: I'll also note -- for the GFS detractors, the SHIPS model gets some of its predictors from the GFS, but all of its model is a purely statistical approach based on a large dataset of historical storms. It is continuously refined by the NHC and its statistically validity is tested on an ongoing basis. It uses a multiple linear regression model to factor in many key variables in intensity forecasting. It is still imperfect, though, and has a tough time with RI and RW sometimes (as all models do currently -- it'd be essentially the holy grail of TC forecasting if we could find a model to accurately predict RI and RW). Just wanted to point this out. SHIPS uses some of the GFS's data, for example, for Relative humidity forecasted. But it is much more than just what the GFS gives.

1719622658002.png
 
wx_guy said:
Officially Beryl, according to the latest SHIPS. At 55%, it is essentially explicitly forecasting a 65kt growth in 72 hours, to around 100 knots (about 110 mph). Still looking potent at 5-6 days out, assuming it avoids major land masses.

EDIT: I'll also note -- for the GFS detractors, the SHIPS model gets some of its predictors from the GFS, but all of its model is a purely statistical approach based on a large dataset of historical storms. It is continuously refined by the NHC and its statistically validity is tested on an ongoing basis. It uses a multiple linear regression model to factor in many key variables in intensity forecasting. It is still imperfect, though, and has a tough time with RI and RW sometimes (as all models do currently -- it'd be essentially the holy grail of TC forecasting if we could find a model to accurately predict RI and RW). Just wanted to point this out. SHIPS uses some of the GFS's data, for example, for Relative humidity forecasted. But it is much more than just what the GFS gives.

View attachment 28905
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I imagine if it rubs up against the mountains of Hispaniola and Cuba, it could have a rough time, but it will likely handle itself better if it avoids them. Would be concerned regardless if I was in the Lesser Antilles.
 
The latest imagery indicates that mid-level easterly shear is still preventing the circulation from becoming vertically stacked. If I recall correctly shear was forecast to begin decreasing by now, but if anything, it seems to have increased since daybreak. Overnight Beryl’s eastern semicircle was able to become more organised, owing to a temporary abatement of shear, but now the shear has returned, resulting in a more disheveled, asymmetric presentation, even though the storm is still generating a lot of persistent convection. The longer the delay in the reduction of shear, the less likely Beryl will become a hurricane over the next three days, before conditions become more hostile. And there is still dry air to deal with in the meantime...

As far as the path is concerned: the NHC’s track is too dependent on the GFS and related output and is therefore almost certainly much too far north.
 
I disagree, Beryl is getting its act together very quickly, *astonishingly quickly* for June. I think everything is lining up pretty well for this storm to strengthen, and I believe we will have a hurricane later today and a major hurricane by Monday before it reaches the islands. I've been an amateur hurricane tracker for 25 years, and to me, this storm has "the look and feel" of a big storm for the season, and I stand by that. I think Beryl is going to be a storm to reckon with. I don't think shear, SAL dust, or anything else is going to significantly impede it.
 
wx_guy said:
I disagree, Beryl is getting its act together very quickly, *astonishingly quickly* for June. I think everything is lining up pretty well for this storm to strengthen, and I believe we will have a hurricane later today and a major hurricane by Monday before it reaches the islands. I've been an amateur hurricane tracker for 25 years, and to me, this storm has "the look and feel" of a big storm for the season, and I stand by that. I think Beryl is going to be a storm to reckon with. I don't think shear, SAL dust, or anything else is going to significantly impede it.
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Yeah. It’s strengthening pretty quickly and has the “look” to it, for lack of a better term. Dust is the only thing I can see being a slight issue, but the environment is overall still supportive for (at least gradual) intensification. It’s already up to 60 MPH sustained.
 
Here's the latest SHIPS at 12z. Pretty strong signal from it that Beryl will rapidly strengthen over the next 24 hours and 72 hours, despite an increase in shear. SHIPS does predict a weakening to TS force towards the end of the period, though, so will have to watch that and any possible land interaction

1719667253155.png
 
wx_guy said:
I disagree, Beryl is getting its act together very quickly, *astonishingly quickly* for June.
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Microwave imagery shows easterly shear on the east side, which does not favour rapid short-term intensification. A budding hurricane would not be facing this at the moment. Furthermore, climatology seems irrelevant to the discussion at hand, which concerns official forecasts and intensity guidance.

I know that the NHC officially upped the winds to 55 knots (65 mph), but normally a strong tropical storm would exhibit a formative eye-like feature; Beryl currently does not. Furthermore, Dvorak estimates only support 45 knots (50 mph) right now. Given the shear, I think that this is still on the weak side, probably 45–50 knots.
 
Casuarina Head said:
Microwave imagery shows easterly shear on the east side, which does not favour rapid short-term intensification. A budding hurricane would not be facing this at the moment. Furthermore, climatology seems irrelevant to the discussion at hand, which concerns official forecasts and intensity guidance.

I know that the NHC officially upped the winds to 55 knots (65 mph), but normally a strong tropical storm would exhibit a formative eye-like feature; Beryl currently does not. Furthermore, Dvorak estimates only support 45 knots (50 mph) right now. Given the shear, I think that this is still on the weak side, probably 45–50 knots.
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With the most recent satellite loop, Beryl does actually appear to be generating an (albeit faint) eye-like signature. It is definitely getting its act together, the convection is bubbling quite substantially all around its core. While I don’t know the most favorable quadrant for convection when looking at intensifying TCs, it certainly seems to be blowing up all around the core of Beryl at the moment, so I’m still on the side that this thing is intensifying quite quickly.
 
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