2017 indicators: SST's / MSLP / SAL / Steering / Instability

[SFLcane]

Could be a long season folks i.e. the return of the long track major hurricanes. It's been sooo long hope many living in particularly Florida be prepared for what could be a rude awaking. Hoping all stay out to sea.

[TheAustinMan]

RAMMB/SSD's instability archives haven't been updating past 2013, so I browsed around for instability charts people happened to save on forums, blogs, and etc. and found enough early season material to stitch together a graph of 2013, 2014, 2015, 2016, and 2017's tropical Atlantic instability. Unfortunately the other graphs aren't posted as often so I probably can't stitch together a similar quantity of data for other regions or tropical cyclone formation potential variables like wind shear or cold water vapor areal coverage.
http://i.imgur.com/Ifzyz7d.png

How did you get this graphic? I'd like to keep it updated for 2017.

I manually made the graphic myself by photoshopping together the various graphs I found that people happened to save on various blogs and forums over the years. Unfortunately that means the graphic isn't updated live online. I will occasionally update the chart and post it here, though of course anyone with a bit of image manipulation skill could update the chart as well. I might forget to update it though at the very end of the year, so I might need to be pinged.

I recently messaged the Satellite Services Division and NESDIS about their archives. They said that while updating the archives is being considered, it's been slipping on their priority lists as the project is no longer funded. However, they also said they would update the archives through 2016 soon, so hopefully we'll be able to access the complete archives for the various products soon.

[cycloneye]

JB says sst's look like the bonanza years for area of West Atlantic.

 https://twitter.com/BigJoeBastardi/status/874309503776370688

[Hammy]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

[tarheelprogrammer]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

Earlier run:


Now:


A lot more shear in key areas on the CFS run recently. However lower pressure trend as shown below.

Earlier run:


Now:

[Bocadude85]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

Models can hardly predict shear accurately a few days in advance. I wouldn't put much stock into shear forecasts 2 months away.

[TropicalAnalystwx13]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

If we had a nickel for every time you were pessimistic about something, we'd all be rich. Shear forecasts at this range are volatile and unreliable. What isn't volatile is a well above-average Atlantic basin with a favorable configuration, as well as a Neutral ENSO which should promote a fairly conducive environment.

[RL3AO]

So if you're putting faith in the CFS showing the eastern Caribbean with above average shear, I'm assuming that means it showing the western Caribbean with below average shear is also significant?

[tarheelprogrammer]

So if you're putting faith in the CFS showing the eastern Caribbean with above average shear, I'm assuming that means it showing the western Caribbean with below average shear is also significant?

Yes, I would say the trend is a positive for western Atlantic development, but if the MDR/Eastern Carib is blasted with shear then long trackers may struggle to get going. I did point out how the pressure trend is to lower pressures across the Atlantic.

[TheStormExpert]

Could be a long season folks i.e. the return of the long track major hurricanes. It's been sooo long hope many living in particularly Florida be prepared for what could be a rude awaking. Hoping all stay out to sea.

Yes it could be somewhat close to the activity and intensity of the storms in 2010. But I now have a gut feeling that the majority of the storms that form will 1) Recurve out to sea, or 2) Hit Central America or Mexico.

[TropicalAnalystwx13]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

If we had a nickel for every time you were pessimistic about something, we'd all be rich. Shear forecasts at this range are volatile and unreliable. What isn't volatile is a well above-average Atlantic basin with a favorable configuration, as well as a Neutral ENSO which should promote a fairly conducive environment.

Even more importantly, the claim isn't even true! Vertical instability has been increasing:

[Ntxw]

2013 would be an example not to assume a huge season is on the way. If not for that fresh memory it would be pretty much a home run big season, got to learn the lessons. It would be easier to call for a monster season with a La Nina of some sort to help. That being said, many indicators are looking favorable than per say if you had a raging Nino inducing 70kts of shear daily which is not present either so a dud season is pretty low in chance also.

[BigA]

Be cautious when analyzing those CFS shear maps for a couple of reasons.

1) The maps are created from the mean of a small number of forecasts, so there is a large amount of volatility.

2) The shear anomaly vectors are as important, or more important, than the shear anomaly shading. Easterly shear sometimes exists, but the primary shear directions that damage or prevent TCs in the MDR are westerly and southwesterly shear.

Thus, look at this image below. Yes, the shading over much of the MDR would indicate above-average shear. But the vectors indicate an anomalous easterly/northeasterly shear, which is the same as saying an anomalously negative westerly or southwesterly shear.



All regions of orange/blue should not be treated equally. I find it more useful to look at the 200 mb and 850 mb zonal wind anomaly maps. Favorable conditions in the MDR tend to occur when the 850 mb zonal wind is anomalously westerly (red), while 200 mb winds are anomalously easterly (purple). Such a situation indicates weaker trade winds and less westerly shear.

[gatorcane]

Very impressive over Africa right now:
http://i.imgur.com/44JmOVS.gif

The latest ECMWF develops a robust closed low in the South-Central Atlantic from one of these waves...in mid-June?!?

[tolakram]

Just keep an eye out for the 2013 like flip of conditions. Don't rely on models, look at actuals in my opinion.

Also, for instability, make sure you are not using the experimental site I usually link to. It's way behind in updates this year and most likely where hammy got her chart from.

[weathaguyry]

This is a link to the website with the updated data, if you scroll all the way down you can find the maps for instability, shear, etc...

http://www.ssd.noaa.gov/PS/TROP/TCFP/atlantic.html

[TheAustinMan]

Speaking of that instability chart, here's an update on the chart I posted earlier with partial data from some of the past few seasons. Instability over the tropical Atlantic at this point of the year is the highest since at least 2013, whose instability tanked in this time period. We'll see what happens over the coming days.

[weathaguyry]

Yes, it looks like now is where the Instability tanked in prior years, so if it stays around average, that may signal an active tropics

[Hammy]

Speaking of that instability chart, here's an update on the chart I posted earlier with partial data from some of the past few seasons. Instability over the tropical Atlantic at this point of the year is the highest since at least 2013, whose instability tanked in this time period. We'll see what happens over the coming days.

Is that massive sudden drop in mid-June of 2013 about when the thermohaline circulation weakened, which is what the quiet season has since been attributed to?

[TheStormExpert]

Vertical instability is slipping below normal yet again. The longer range models are also starting to trend towards less favorable conditions (particularly more shear) during August and September, and I've had a gut feeling since about April that this season is going to massively under-perform everyone's expectations.

Weren't you just the other day calling for the opposite?