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2023 Tropical Tracking Thread


SnowenOutThere
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The thing I’m proudest of honestly is the pattern recognition. I first highlighted on August 16 that the highest potential of all the potential areas of activity was with the CAG. On August 18 I first said I thought something would develop with a land threat the last week of August.

The first advisory came on August 26. 

Not being a met, it’s a source of pride to be a competent tropical watcher/forecaster. Now to the point where I can effectively chase. 

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6 hours ago, WxWatcher007 said:

We can thank Franklin for nearly single handedly accomplishing this :)

He was getting a bit long in the tooth there. 

 

No longer tropical but it's fascinating watching Jose get absorbed into him. We don't see two named systems collide very often! Maybe we can get all four to kinda squish together...

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Gert came back from the dead, and Katia has formed. 

All eyes should be on 95L. Forecast has been excellent thus far. 

WxWatcher007 Peak Season Forecast (Aug 20-Oct 20)
Named Storms: 13 (7)
Hurricanes: 6 (2)
Major Hurricanes: 3 (2)

Emily, Franklin (MH), Gert, Harold, Idalia (MH), Jose, Katia

40 minutes ago, WxWatcher007 said:

The NHC has designated our AOI in the eastern Atlantic as Invest 95L. It already has a good look to it, with significant spin and some disorganized convection. 

giphy.gif

 

Normally, I am more muted when we're at the invest stage, but not this time. I believe this is the strongest signal we've seen for a long track CV major hurricane in quite some time. 

Why? The environment ahead looks tremendous not just for tropical genesis but significant intensification in the MDR. 

First, it's the moisture. Unlike early August, where SAL and subsidence dominated the MDR, we have a more moist and unstable environment thanks to the presence of much stronger preceeding waves scouring out the SAL. 

UvbR5zq.jpg

giphy.gif

Look at the dramatic rise in instability in the MDR since August. It's more than enough, as we've seen. 

WxXZdE6.gif

Obviously the thermodynamic environment is excellent. We have strong SSTs and OHC through the MDR and basin. 

TfVp8lD.png

vh7AynY.png

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With a strong ridge building in over the Atlantic, wind shear should initially be low. That alone is enough for TC genesis. There is a long runway of low shear in the MDR.

DF2R8sY.gif

However, what sets this apart from other setups, especially in recent years, is that it looks like the orientation of the steering pattern is going to create ideal conditions for ventilation. 

From Eric Webb

PygqIEr.jpg

Folks, that's big time. All systems seem poised to allow for TC genesis, followed by an increasing level of organization and eventually, intensification. 

It's reflected on the guidance consistently. Each operational model has a strong system nearing the Antilles.

 

6GsfVdB.png 

5g4bG2S.png

With a strong ridge over the Atlantic, the Antilles have to watch very closely, including Puerto Rico. Once this gets to the Antilles, as you can see above there is a lot of guidance that tries to round this around the ridge. All bets are off then, as we turn our attention toward the East Coast steering pattern relative to the Atlantic ridge. 

Climo always favors OTS at this stage, but given the presence of strong ridging showing up on the guidance, this may be one that we're watching for a while, especially as guidance tends to underplay the strength of ridging. This is also where we need to watch the orientation of troughing in the eastern US, but that'll be at least 7-10 days away. 

At the very least, this is likely to be a threat to the Antilles and a significant ACE producer. 

In my estimation, 95L has the best chance to be the strongest TC in the basin this season. 

 

 

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That solution would require perfect timing, but everyone should be watching the strength of this Atlantic ridge.

This is not a slam dunk OTS pattern IMO, even if that solution is still favored at this time, and if it’s a threat to the US I think it’s an EC threat rather than buzzsaw through Florida threat.

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18z GFS with one of 877 possible outcomes at this range. Too far to parse details. Timing of northern stream trough pattern, strength of surface ridge in the Atlantic, and perturbations within the mid-level flow that won’t be parsed until another 10 days out will play a role in the path of the storm. 
 

Non-zero number for direct east coast impact, but number for the time-being is small unless noted otherwise. Just follow along per the usual at this range. 

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Did a long post in the main thread. 

9 minutes ago, WxWatcher007 said:

Let's take a look at 95L, which will almost certainly be Tropical Storm Lee by the end of the day. The theme of this post will be managing expectations...

As @Windspeed's post showed, we started to see 95L really take a leap forward last night, and this morning it's basically a TC and the NHC is likely to start issuing advisories at 11am. 

giphy.gif 

That's about as good as you're going to get for a tropical wave in the MDR, a stark contrast from a lot of the slop and slow developing waves we've seen in recent years. 

A wider view shows just how far away this one is, and provides some clues to the landscape ahead. 

giphy.gif

The first thing I notice here is concentrated convection around 95L. While there is drier air around, there's a solid pocket of moisture that's developing around the system. 

In addition, and this is important, there's very little shear. An upper level low to the north is too far north to inhibit development, and will probably do the opposite as an outflow channel gets established further west and an upper level anticyclone develops overhead. 

Intensity guidance is high end as a result. 

QrZErS9.png

Some may look at this and say "Oh boy, a 5 is coming!". Not so fast my friend. This is almost certainly our next major hurricane, and I'd go as far as saying this is our next category four hurricane, our third of many thought in early August would be a quiet season. Once you get to these high end thresholds however, you have to watch for structural changes such as ERCs that could cap intensity. 

For intensity, the expectation should be a high end hurricane, but while it is possible, expecting a 5 is asking too much IMO. 

Now to why I'm actually writing this post.

The forecast track

If we're being honest with one another, everyone has their rooting interest. Whether you want a land threat, eye candy that stays out to sea, or just to be right with whatever it is you've already posted, we all see posts with bias. That's not necessarily a bad thing if you know how to sort through it. 

I'd hope that after all these years most of you see me as an objective poster with regard to tropical, but I'm often working to check my bias too.

Taking a step back, I think it's essential for everyone to remember how far out this system still is from having a well defined track evolution in the long range. 

I'm sure there are some reading that line and saying "well, that's what weenies always say". I agree. But I urge everyone to look past prior storms and analyze this current setup. 

Mb1Hyk3.png

 

Step I--WNW Movement Around Atlantic Ridge (High Confidence in 0-5 Days)
The current phase we're in is high confidence on the guidance and it makes sense in analyzing the steering environment. 95L is a relatively low rider currently, but as it moves westward it will intensify rapidly and will begin to gain latitude. This is a saving grace for the Antilles, as it should allow future Lee to travel WNW around an Atlantic ridge. Even accounting for the lack of an established low level center, this one should pass to the north of the Antilles. 

5W3nnOw.png

xwCg7RQ.png

I am posting the op runs from 00z for comparison purposes because they are similar 5 days out. 

Step II--Turn Northward (Moderate Confidence in 6-9 Days)
I think there's high confidence that a turn occurs, but when and how sharp are open questions. On both the GFS and Euro, and by extension their ensembles, it's easy to see why a turn happens and why a turn itself is high confidence.

There's troughing in the E CONUS that provides a pathway for a northward turn. How far west future Lee can get before a turn may be very important to New England and especially Atlantic Canada. 

Once again, looking at the 00z operational GFS and Euro, you see the evolution. This first trough you see very early in the period allows for the turn, followed by a second and critical piece of troughing later in the 6-9 day period.

giphy.gif

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I'm inclined to trust the ensembles that show a turn between 65-70W, but this is something that is of lower confidence than the turn itself. This is where interests in Bermuda must watch closely. The degrees may matter if the next step gets tricky. 

ahu4tHG.png

Part III--The Final Turn (Low Confidence in 10+ Day Period)
This stage is the whole reason why I think it's far too early to lock in any land or OTS solutions. This is where you consider the probabilities rather than deterministic solutions. 

Recall the D6-9 GFS and Euro runs. The first trough is only enough to turn 95L north. It's not enough as currently modeled to sweep 95L out to sea as the models are trying to show a ridge attempting to build over the Maritimes/Atlantic.

That means that a second trough is required for a kick.

The problem is, while a Midwest trough is looking like it will try to dive in quickly after the first, it's unclear whether we see a positively tilted trough where the westerlies effectively kick 95L to the northeast and OTS, or a cutoff low that would effectively capture future Lee and pull it 1) northward into Atlantic Canada, or 2) northwestward into New England. 

Here are the ensembles at D10. This is a trend gif, showing the various solutions over the past two days at 240. Look at the ridging and troughing. The EPS has shown deeper eastern US troughing in recent runs with more ridging over the north Atlantic while the GEFS are kind of all over the place. Verbatim, it still may not be enough for a bona fide land threat outside of Bermuda, but there's enough uncertainty in the long range to pay attention along New England and Canadian Maritimes. 

giphy.gif

giphy.gif


Again, it's about keeping expectations in check. Long range consensus does not necessarily imply accuracy. We are going to need time to figure out what the steering pattern looks like after that northward turn occurs. A trend toward the coast can easily reverse at this range, and so can the current OTS solutions. 

If I were placing odds at this moment on what would happen it'd be the following: 

  • 65% OTS--because it is extremely hard to trust a cutoff low being positioned and timed "perfectly" as 95L turns north to create a land threat.
  • 20% Atlantic Canada Threat--because an extended northward track with a slight bend (a la Fiona) is more likely with any kind of cutoff or negatively tilted trough. 
  • 15% New England Threat--because the turn north is more likely to happen east of the region and a threat would require the aforementioned positioning and timing to be precise for what'd likely be some type of extended NNW to NW heading.

These numbers will change, but the overall message in this very long analysis is that while we have higher confidence in the 0-5 and perhaps even higher confidence in some aspects of the 6-9 day period, there is a lot that needs to be sorted out given the steering pattern potential beyond ~day 8. 

 

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4 hours ago, H2O said:

Saw a tweet the other day about how long track systems historically turn but not all. 
 

Florence is a good example. Odds favor OTS but it’s just too far out to know today. 
 

In other words..we just don’t know. 

100% the euro today just jumped well west 

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Back on August 11 when I predicted in this thread that the Atlantic would come alive in the next few weeks I was basing this on the ECM predicted Sept. MSLP.   This has shifted a little with the 9/01 update but the August MSLP for Sept. was certainly a harbinger.

Jose and Katia were so quick and gone that they fell through the cracks for me.  Just as well!!

The NHC progs Lee to be a major cat. 4 on Sunday at 65w.

The 18z GFS takes Lee north 200 miles west of Bermuda on Thursday.  It may later threaten Atlantic Canada.

The spaghetti models still re-curve Lee by 70w but that may become problematic.

If we can pump that NA ridge and hold the trough over the OV, we may be in business. A long shot but better than no shot.

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