2021 Indicators: SST's / SAL / MSLP / Shear / Steering / Instability / Sat Images

[SFLcane]

If the EPac was capable of producing actually decent TCs then this phase with the -VP cell and MJO forcing would be interesting…but it’s not, so now we’re all just stuck nitpicking over shear forecasts and MJO propagation and the most minute VP anomalies while the EPac tosses out slop storm after slop storm that aren’t worth giving much attention.

Well, the thing is it's the convection that matters. As long as the EPAC is convectively active (even if they are slop TCs) it's gonna hinder the Atlantic.

If late week’s wave develops and sticks to a low latitude early on but then gets north of the Caribbean, would it survive? I don’t think the EPac-induced TUTT gets that far east, so maybe it could be something interesting before running into a wall of shear.

The WPac is also out of commission for doing anything worthwhile because the current setup out there is garbage. Only weak, strung-out TCs for the time being it seems.

Yeah although again I wonder if the convection (monsoon trough) is causing some downstream enhancement of the TUTT.

[Category5Kaiju]

EPac storms are often underperforming their expectations by the NHC at least this year. TD 9E was expected to become a tropical storm, yet it never happened. There have been disturbances in the EPac that were given high chances of development (at or above 70%) this year, yet they did not form. This is evidence that the EPac is hostile for tropical cyclogenesis. The only thing that is making the EPac convectively active is a favorable MJO phase.

This is why for what I am seeing for the foreseeable and logical future, I simply do not think a rapid fire succession of major EPAC hurricanes as the GFS has been showing again and again will really come to fruition (sure, maybe one or two more storms, but definitely not expecting a 1980s/1990s like paintball gun of powerful hurricanes). I also think that while it will be eventual, the models will start realizing that the EPAC may not be as favorable as they have been showing and begin to favor showing activity occur in the Atlantic instead (which, mind you, looks to be barren on many of these models, even until mid-month which I find very weird).

[Blown Away]

During above average seasons having a mid August hurricane or major is not that uncommon, many examples. The TW's moving off Africa now will be in the NE Caribbean in the 8+ day window and any CONUS threat is @12+ days out, so the timing is about right and seeing some hints in the long range modeling now is expected IMO. It's nearing go time if this is truly going to be an "Above Average" season as predicted.

[Stormybajan]

 https://twitter.com/webberweather/status/1422196254872805394



Great tweet from Eric Webb on the MJO!

[Teban54]

I see we're approaching the peak of the season cancel season.

[toad strangler]

I see we're approaching the peak of the season cancel season.

[AnnularCane]

I see we're approaching the peak of the season cancel season.

Usually July into the first half of August when a general lack of activity and/or not much on the models prompts season cancelling.

[cycloneye]

 https://twitter.com/AndyHazelton/status/1422231276522774528

[Category5Kaiju]

You know that Avicii top hit song "Wake Me Up?" For some reason I always think of that song everytime we're in late July/early August and I see wx enthusiasts on social media comment about them wanting to like go back to sleep and get up when the real Atlantic action begins or making those sleeping emojis after seeing the Atlantic dry and sheared with the MJO-boosted action in the EPAC and with no model support for any major Atlantic storms anytime soon

[Shell Mound]

I am skeptical of the EPS for the wave just off the African coast currently. Next wave likely has a better chance to develop.

https://twitter.com/AndyHazelton/status/1422155493372481536

https://twitter.com/AndyHazelton/status/1422156861734785028
https://twitter.com/AndyHazelton/status/1422160640752431109
https://twitter.com/dmorris9661/status/1422162833295527941
The tone of the discussion in the thread sounds very bearish in regard to the Atlantic through the last week of August. In particular some contributors mention cooler SST along 15°N that would hinder any system that manages to extricate itself from the ITCZ. Others also note that the EPS has apparently trended slightly toward the GEFS’s slower eastward progression of the -VP over the EPAC. They only intimate that due to climatology (!) the Atlantic “might” become a little more conducive for TCG beyond August 20, particularly during September, and that the -VP over the EPAC needs to be centred east of 60°W for the Atlantic to enter its most favourable state. To me all this sounds extremely bearish.

Sounds like confirmation bias to me. Have only really seen people bearish on the first couple of weeks, then it's really all systems go as MJO and climo align for a peak season burst it looks like

The CFSv2 shows an East-Coast trough, however subtle, developing beneath northward-displaced ridging during the last week of August and first week of September, replacing the landfall-friendly pattern that is forecast for the first two-thirds of August. Mid-level flow is northwesterly over most of the Northern Tier during the peak of the Atlantic season, which would normally favour OTS and/or low-latitude tracks. If the latter were to occur, they might stay well to the south of the CONUS and affect Central America instead. So it appears to be good news for the CONUS that the expected increase in activity during late August and early September is likely to coincide with a pattern-shift that discourages landfalls. Note the textbook-style +EPO/west-based -NAO in place, which would tend to suppress the Bermuda High.

[Category5Kaiju]

And....the NHC has a lemon for the possible quick spinup near the Cabo Verde Islands recently hinted by the GFS and Euro

[captainbarbossa19]

https://twitter.com/AndyHazelton/status/1422156861734785028
https://twitter.com/AndyHazelton/status/1422160640752431109
https://twitter.com/dmorris9661/status/1422162833295527941
The tone of the discussion in the thread sounds very bearish in regard to the Atlantic through the last week of August. In particular some contributors mention cooler SST along 15°N that would hinder any system that manages to extricate itself from the ITCZ. Others also note that the EPS has apparently trended slightly toward the GEFS’s slower eastward progression of the -VP over the EPAC. They only intimate that due to climatology (!) the Atlantic “might” become a little more conducive for TCG beyond August 20, particularly during September, and that the -VP over the EPAC needs to be centred east of 60°W for the Atlantic to enter its most favourable state. To me all this sounds extremely bearish.

Sounds like confirmation bias to me. Have only really seen people bearish on the first couple of weeks, then it's really all systems go as MJO and climo align for a peak season burst it looks like

https://i.ibb.co/K0Rx6XD/Trough-1.png

The CFSv2 shows an East-Coast trough, however subtle, developing beneath northward-displaced ridging during the last week of August and first week of September, replacing the landfall-friendly pattern that is forecast for the first two-thirds of August. Mid-level flow is northwesterly over most of the Northern Tier during the peak of the Atlantic season, which would normally favour OTS and/or low-latitude tracks. If the latter were to occur, they might stay well to the south of the CONUS and affect Central America instead. So it appears to be good news for the CONUS that the expected increase in activity during late August and early September is likely to coincide with a pattern-shift that discourages landfalls. Note the textbook-style +EPO/west-based -NAO in place, which would tend to suppress the Bermuda High.

All it takes it for one storm to fall under a different setup and it can be a completely different story. The general pattern might be this for September, but that does not mean that all the storms are going to stay south of the CONUS.

[captainbarbossa19]

I see we're approaching the peak of the season cancel season.

Usually July into the first half of August when a general lack of activity and/or not much on the models prompts season cancelling.

The best part comes when the experts start to doubt that the season as a whole is going to be active.

One week later: Storms form

Experts:

After this many experts say, "I always knew this was going to happen. Forecast verified!"

[Shell Mound]

Sounds like confirmation bias to me. Have only really seen people bearish on the first couple of weeks, then it's really all systems go as MJO and climo align for a peak season burst it looks like

https://i.ibb.co/K0Rx6XD/Trough-1.png

The CFSv2 shows an East-Coast trough, however subtle, developing beneath northward-displaced ridging during the last week of August and first week of September, replacing the landfall-friendly pattern that is forecast for the first two-thirds of August. Mid-level flow is northwesterly over most of the Northern Tier during the peak of the Atlantic season, which would normally favour OTS and/or low-latitude tracks. If the latter were to occur, they might stay well to the south of the CONUS and affect Central America instead. So it appears to be good news for the CONUS that the expected increase in activity during late August and early September is likely to coincide with a pattern-shift that discourages landfalls. Note the textbook-style +EPO/west-based -NAO in place, which would tend to suppress the Bermuda High.

All it takes it for one storm to fall under a different setup and it can be a completely different story. The general pattern might be this for September, but that does not mean that all the storms are going to stay south of the CONUS.

Yet this general pattern would make a (significant) hurricane impact on the CONUS far less likely than a different pattern would. That is still salient.

[AutoPenalti]

 https://twitter.com/webberweather/status/1422230705300459530

[AnnularCane]

Usually July into the first half of August when a general lack of activity and/or not much on the models prompts season cancelling.

The best part comes when the experts start to doubt that the season as a whole is going to be active.

One week later: Storms form

Experts:

After this many experts say, "I always knew this was going to happen. Forecast verified!"

Almost like a cue for the Atlantic.

"Okay, the experts are showing doubt. Time to start spinning!"

[tolakram]

The CFSv2 shows an East-Coast trough, however subtle, developing beneath northward-displaced ridging during the last week of August and first week of September, replacing the landfall-friendly pattern that is forecast for the first two-thirds of August. Mid-level flow is northwesterly over most of the Northern Tier during the peak of the Atlantic season, which would normally favour OTS and/or low-latitude tracks. If the latter were to occur, they might stay well to the south of the CONUS and affect Central America instead. So it appears to be good news for the CONUS that the expected increase in activity during late August and early September is likely to coincide with a pattern-shift that discourages landfalls. Note the textbook-style +EPO/west-based -NAO in place, which would tend to suppress the Bermuda High.

Since the weather is never static, like a single plot shows, how do we determine what the change in risk % is based on a model that tried to predict long term patterns? It that a 10% greater chance of a trough? Is it a 5% greater change of a stronger ridge? The plots are both useful and potentially confusing if one looks at them as static. There will rarely be a constant ridge like what shows on that diagram, but ridging might be more common.

[cycloneye]

 https://twitter.com/AndyHazelton/status/1422265890767261699

[AlphaToOmega]

The current ECMWF MJO forecast suggests Phase I by August 7, Phase II by August 12, and Phase III by August 22. Phase IV of the MJO should be present by late August and early September. I would ring the bell on August 6, not August 20.

[Blown Away]

JB getting fired up for August.