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

[TheStormExpert]

The problem isn't being able to reach average seasonal levels, it's being able to reach above-hyperactive seasonal levels as many are forecasting (especially NOAA).

[RL3AO]

The problem isn't being able to reach average seasonal levels, it's being able to reach above-hyperactive seasonal levels as many are forecasting (especially NOAA).

Who are the "many" predicting a hyperactive season?

[tolakram]

They are not forecasting hyperactive, just above normal.

I think one of the big mistakes with understanding hurricane season, especially the Atlantic, is the fact that generally the Atlantic is hostile for development. Right now we have the African wave gun (think teeshirt gun) spitting out disturbances and these are spreading out into the Atlantic. If/when one finds a good spot it will develop. The more waves the better the chance one will develop. 2005 was a record year because waves were plentiful AND conditions were much better than average further west. This year conditions seem average but disturbances above average which should result in an above average season.

But in the end it's all luck, chance, being in the right place at the right time. Andrew is the textbook example of that.

So here we go into the peak of the season with 3 and pretty soon 4 significant disturbances travelling through the Atlantic. No clue if these will actually result in anything but it certainly increases the odds.

I'm posting this now so I can look back once the season is over knowing what happened. I have to think 91, 92, soon to be 93, or what may be 94 next week is going to develop, and one will probably be a major. Where it goes, who knows, but the further west a wave gets the higher the risk for the US.

[SFLcane]

 https://twitter.com/Adriansweather/status/897965369733918720

[Steve]

Right Mark. That's what I see too. NOAA has a big spread of 14-19, 5-9 and 2-5. I guess if they hit the top of the range, 19-9-5 that's probably hyper. 2010 was the last year that saw a ton of storms. And then 2005 and 1933 are the benchmarks. If average is 12-6-3 and we end up like 15-5-2, that's not hyper. I'm not even sure if there is an actual definition or where I'd come in at. 18NS maybe or more than 11 hurricanes?

[RL3AO]

I'm not even sure if there is an actual definition or where I'd come in at. 18NS maybe or more than 11 hurricanes?

Usually defined as at least 175% of average ACE.

[Steve]

I'm not even sure if there is an actual definition or where I'd come in at. 18NS maybe or more than 11 hurricanes?

Usually defined as at least 175% of average ACE.

Gotcha. I guessed 106. I don't think that many entities predict ACE, do they? Weatherbell does, and know Bastardi was like 90-115. Average I remember was somewhere around 100ish. I don't think in the context of ACE that many people are calling for hyperactive? I only remember 2 of the 100 S2K guesses being at 200. Maybe there were a couple in the high 100s? Wiki counts ACE and numbers of storms the way they present Hyperactive. I don't know. But I don't see 175 ACE this year at all. I guess it's possible with some long trackers (Ivan '04 I think was near 65-70), but I wouldn't bet a dollar that we'd hit that bar this year. I haven't seen anyone else saying that, but maybe I haven't looked hard enough?

[RL3AO]

I'm not even sure if there is an actual definition or where I'd come in at. 18NS maybe or more than 11 hurricanes?

Usually defined as at least 175% of average ACE.

Gotcha. I guessed 106. I don't think that many entities predict ACE, do they? Weatherbell does, and know Bastardi was like 90-115. Average I remember was somewhere around 100ish. I don't think in the context of ACE that many people are calling for hyperactive? I only remember 2 of the 100 S2K guesses being at 200. Maybe there were a couple in the high 100s? Wiki counts ACE and numbers of storms the way they present Hyperactive. I don't know. But I don't see 175 ACE this year at all. I guess it's possible with some long trackers (Ivan '04 I think was near 65-70), but I wouldn't bet a dollar that we'd hit that bar this year. I haven't seen anyone else saying that, but maybe I haven't looked hard enough?

Most forecasts I've seen have been in the 115 to 135 range. Average is about 95 to 105 depending on the time-period you use.

[Andrew92]

I totally agree with those that say a major is coming down the pipe, likely with at least 91L, 92L, and the next two waves. The fact of the matter is it is that time of year and the western half of the Atlantic looks mighty favorable. You add in a strong ridge steering storms in the direction of those favorable conditions, and it really feels like a matter of when, not if.

I don't trust the models per se, but I think 91L will likely form first into Harvey, and careen across the Caribbean. I just really hope the Gulf of Honduras doesn't do its "magic" and allow it to ramp up quickly like many have done there, but this is certainly a good candidate for that first major. I smell a track overall similar to Franklin, but quite possibly stronger unfortunately.

92L is the best immediate bet to head to the United States. However, it may pass through the unfavorable TUTT on its way, and there is the wrinkle of whether or not it passes over especially Hispaniola, but also Cuba. I tend to think this one will track further north and eventually become Irma, but I am not confident in going a lot further especially with intensity due to the variables in play. The Bahamas and Florida would do well to pay attention though, to be sure. Beyond there, I probably lean towards the Gulf.

Beyond that, too early to tell, and models are all over the place. However, a powerful hurricane or two continue to be consistently on a lot of recent and/or current plots, so it feels like it's coming. Hopefully I am wrong about a lot if not all of what I am saying, but I would be lying if I said I wasn't nervous. But for now, it's still just a time to wait, watch, and be ready just in case.

-Andrew92

[Steve]

Thanks RL3AO. To bring it current, it looks like Gert added some ACE, and we're around 14-15. So to be average, we'd have about 85% of the ACE left to go. What's interesting about the moment is we have 91L, 92L, the wave after that (not sure if it's been classified yet) and the next one yet to come off Africa. WPAC has recently been sort of shut down because most of the energy is rolling our way. On the one hand, none of these 4 systems might form into anything or even if they did could recurve. On the other hand if there was ever a time I didn't want to see a burst of storms it's the second half of August. You'd have to think in the near term with these 4 we'll get at least something to develop. So maybe max 25 ACE to come out of the 4 areas? That would still leave at least half more to go for future systems.

[Alyono]

 https://twitter.com/Adriansweather/status/897965369733918720

and that's why a Kelvin wave is not going to aid in genesis. That is at least as bad as 2013 for the tropical Atlantic

[Hammy]

Could this year end up going without a major if Gert doesn't make it?

[Steve]

Yeah but will it matter (was response to Alyono)? MJO looks like it will go into 1 slightly amplified. That's probably enough of a signal to say that it's not going to be dead right now due to the mid level dry air whereas in some other circumstances, you might not have any development at all. Maybe in this instance it will have helped to hold things back a bit or kept them from getting completely out of hand?

[AxaltaRacing24]

:uarrow: Could this year end up going without a major if Gert doesn't make it?

That's highly unlikely. The western ATL is far too favorable for that.

[Alyono]

:uarrow: Could this year end up going without a major if Gert doesn't make it?

no, the west Caribbean could easily spawn a cat 5 given how favorable it is. It's only the tropical Atlantic itself that is as bad, if not worse than, 2013

[Hammy]

:uarrow: Could this year end up going without a major if Gert doesn't make it?

no, the west Caribbean could easily spawn a cat 5 given how favorable it is. It's only the tropical Atlantic itself that is as bad, if not worse than, 2013

Any idea what's causing this level of dry air?

[tarheelprogrammer]

:uarrow: Could this year end up going without a major if Gert doesn't make it?

no, the west Caribbean could easily spawn a cat 5 given how favorable it is. It's only the tropical Atlantic itself that is as bad, if not worse than, 2013

Any idea what's causing this level of dry air?

I second this. I heard several people the last few months talk about how the SST configuration was going to rid the Atlantic of dry air problems, and instead it is as dry or drier than 2013. What could be the cause of that?

[TheStormExpert]

Here's something people like Levi Cowan was worrying about allowing the Subtropical Atlantic to potentially rob the Tropical Atlantic of it's energy. The SST configuration now screams unfavorable for an active rest of the season with warm tropics, warm mid-latitude, and warm far North Atlantic. I've had a feeling this was going to happen for weeks now.

[TheStormExpert]

The problem isn't being able to reach average seasonal levels, it's being able to reach above-hyperactive seasonal levels as many are forecasting (especially NOAA).

Who are the "many" predicting a hyperactive season?

I guess I made a typo.

But surely NOAA's prediction of an potential hyperactive season will likely bust with the latest SST configuration. Luckily for them they have a wide range of outcomes on the table with numbers as low as a near average season.

[Steve]

The problem isn't being able to reach average seasonal levels, it's being able to reach above-hyperactive seasonal levels as many are forecasting (especially NOAA).

Who are the "many" predicting a hyperactive season?

I guess I made a typo.

But surely NOAA's prediction of an potential hyperactive season will likely bust with the latest SST configuration. Luckily for them they have a wide range of outcomes on the table with numbers as low as a near average season.

So what do you think happens?