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

[Category5Kaiju]

Yeah I have no idea what is going on with these models, but I really cannot believe we’ll see no deep tropic system until September. I mean unless this year was another 2013, but so far from my understanding 2021’s background conditions and what we have seen thus far do not compare in any way with what was observed 8 years ago. Instability definitely does not seem to be a concern this year

[toad strangler]

We all knew this depressed background state was coming. It has been advertised very well and is verifying. Yet, we still have a lemon out there to gnaw on as we just start entering the teeth of it. Nobody here has jumped ship yet and that’s very noteworthy LOL

[weeniepatrol]

I continue to wait for August 20th (ringing of the bell) before even looking at models. Anything between now and then is just extra red meat, folks!!!

[Category5Kaiju]

If I had to bet between the chances of having to wait until mid September to see actual action and major hurricanes in the Atlantic or a kangaroo talking to me in Russian, I’d bet on the latter.

[SFLcane]

Guys relax! The Africa signal still looks good so it could be a fluke. It could be something with all the Pacific activity. The real season for me personally starts Aug 20th through October 20th.

[AlphaToOmega]

Near-average shear is expected in the MDR, but above-average shear is expected in the Caribbean for early August. We could see storms that mimic Gonzalo (2020) or Danny (2015) during this time period. This is expected, for Caribbean activity typically does not ramp up until later in the season.

[Category5Kaiju]

I have a question and any insight would be greatly appreciated. What is the purpose of having those models predicting stuff almost 45 days into the future, and has there ever actually been a time when those kinds of extremely long range models actually correctly predicted a storm to form that far into the future (and if so, what about how well it predicted its track and intensity?)

[Category5Kaiju]

Near-average shear is expected in the MDR, but above-average shear is expected in the Caribbean for early August. We could see storms that mimic Gonzalo (2020) or Danny (2015) during this time period. This is expected, for Caribbean activity typically does not ramp up until later in the season.
https://i.postimg.cc/nhHvNpdG/cfs-avg-ashear-Mean-atl-3.png

The Gulf though...

[Stormybajan]

Maybe we’re skipping this season? Lol…

No TCs through September 5 on the EPS control.

https://i.postimg.cc/Vvvcw0Gn/8-B884703-C69-B-4-E72-A970-A0-B34-E90-C874.png

Theres no way we should have to wait until September 5th for a HURRICANE to form much less a storm lol. By August 1st im sure this model will be picking up on something in that 45 day timeframe. If we get to August 10th-15th and models STILL arent picking up on anything then we should be wondering whats going on but thats still 3 weeks away so we have time to chill for now

[Category5Kaiju]

Maybe we’re skipping this season? Lol…

No TCs through September 5 on the EPS control.

https://i.postimg.cc/Vvvcw0Gn/8-B884703-C69-B-4-E72-A970-A0-B34-E90-C874.png

Theres no way we should have to wait until September 5th for a HURRICANE to form much less a storm lol. By August 1st im sure this model will be picking up on something in that 45 day timeframe. If we get to August 10th-15th and models STILL arent picking up on anything then we should be wondering whats going on but thats still 3 weeks away so we have time to chill for now

I mean how reliable is a model that looks out that far into the future when determining individual storm formations? I'd have to think that predicting something 45 days in advance is not as useful and skillful with many error sources possible compared to doing the same even within a 16 day timeframe.

[AlphaToOmega]

Near-average shear is expected in the MDR, but above-average shear is expected in the Caribbean for early August. We could see storms that mimic Gonzalo (2020) or Danny (2015) during this time period. This is expected, for Caribbean activity typically does not ramp up until later in the season.
https://i.postimg.cc/nhHvNpdG/cfs-avg-ashear-Mean-atl-3.png

The Gulf though...

That would only be a problem for storms that form from the Central American Gyre. Waves that develop from Africa would not survive the shear of the Caribbean.

[Deshaunrob17]

45 day model are usually useless - especially coming from the Euro in the Atlantic
However, let’s say the Euro is right and nothing forms in the Tropics during August, the rest of the season still could be jammed pack!!! If anything the last 5 years taught is that August activity doesn’t really correlate with September, October and even November. Furthermore, I really do feel that the Cabo Verde is starting later than it usually does. Even 2017 couldn’t pull off a hurricane in the MDR . These times are different from the days of Dean 2007, Danielle (2010) , Frances (2004)and so on. We’re more seeing jammed packed September and October . Ironically, 2015 (the super El Niño year) probably was the last time we had a MDR hurricane in August ( I think )

[AtlanticWind]

Maybe we’re skipping this season? Lol…

No TCs through September 5 on the EPS control.

https://i.postimg.cc/Vvvcw0Gn/8-B884703-C69-B-4-E72-A970-A0-B34-E90-C874.png

Theres no way we should have to wait until September 5th for a HURRICANE to form much less a storm lol. By August 1st im sure this model will be picking up on something in that 45 day timeframe. If we get to August 10th-15th and models STILL arent picking up on anything then we should be wondering whats going on but thats still 3 weeks away so we have time to chill for now

I mean how reliable is a model that looks out that far into the future when determining individual storm formations? I'd have to think that predicting something 45 days in advance is not as useful and skillful with many error sources possible compared to doing the same even within a 16 day timeframe.

The Euro cant pick up storm genesis in 72 hours a lot of the time.

[Shell Mound]

Maybe we’re skipping this season? Lol…

No TCs through September 5 on the EPS control.

https://i.postimg.cc/Vvvcw0Gn/8-B884703-C69-B-4-E72-A970-A0-B34-E90-C874.png

Watch as someone uses this as evidence that the season will be inactive

I could have sworn a while ago that the model was showing an MDR storm circa August 22.

The EPS, whether long-range or otherwise, tends to miss a lot of weak systems and marginal hurricanes, but it does well in terms of gauging the potential for intense activity. So I think it can be used to assess the potential for higher-end long-trackers during the peak of the season. In this case it agrees relatively well with the BoM’s ACCESS, the JMA, and the CFSv2 in suggesting a suppressed ITCZ, a strong TUTT, a fairly coolish MDR vs. the subtropics, and possible sinking air over the basin during the “traditional” peak. Also, the balance of the guidance suggests some additional VWS from EPAC convection/activity during the same timeframe, especially through the first half of September. So while I wouldn’t “cancel” the season per se, I think there is a good chance that it will underperform relative to expectations/forecasts. We shall see.

[Shell Mound]

...

I didn’t count Ike, as it was a CV-type system, and, moreover, it occurred in September; I was only looking at Cat-4+ impacts on the CONUS during the month of August. Among hyperactive seasons, 2005, like 2020, was very unusual in that most of its activity was concentrated in the western part of the basin, whereas most hyperactive seasons tend to feature intense activity farther east, in the MDR. During inactive phases, one actually tends to see more “homegrown” development or formation in the subtropics than activity in the MDR. During inactive cycles storms tend to be smaller, weaker, and concentrated farther west vs. storms that form during active cycles. Inactive cycles also tend to feature a greater proportion of small storms that intensify rapidly close to shore, like the 1935 Labor Day hurricane, Gracie (1959), Camille (1969), Celia (1970), Eloise (1975), Diana (1984), or Michael (2018). Unlike large systems such as Beulah (1967), Agnes (1972), Frances (2004), Ivan (2004), Katrina (2005), or Ike (2008), smaller systems tend to produce fewer tornadoes as they move ashore, usually produce less flooding from either surge or precipitation, and confine their worst wind-related impacts to small areas. Andrew barely produced TS winds just 30 n mi north of its eye, and Charley was even smaller than Andrew. A tiny but intense system would basically need to directly hit the very centre of a populated area to produce extreme impacts within the span of a few miles, with minimal impacts on either side of that swath. So the possibility that large, intense systems, which tend to form farther east before tracking westward, will be less likely in 2021 is very good news for the Western Hemisphere. I’d rather take my chances with another Andrew than with another Audrey, Carla, or Katrina.

So you believe that we are now in a less active cycle aka -AMO?

In effect, yes.

[Category5Kaiju]

Maybe we’re skipping this season? Lol…

No TCs through September 5 on the EPS control.

https://i.postimg.cc/Vvvcw0Gn/8-B884703-C69-B-4-E72-A970-A0-B34-E90-C874.png

Watch as someone uses this as evidence that the season will be inactive

I could have sworn a while ago that the model was showing an MDR storm circa August 22.

The EPS, whether long-range or otherwise, tends to miss a lot of weak systems and marginal hurricanes, but it does well in terms of gauging the potential for intense activity. So I think it can be used to assess the potential for higher-end long-trackers during the peak of the season. In this case it agrees relatively well with the BoM’s ACCESS, the JMA, and the CFSv2 in suggesting a suppressed ITCZ, a strong TUTT, a fairly coolish MDR vs. the subtropics, and possible sinking air over the basin during the “traditional” peak. Also, the balance of the guidance suggests some additional VWS from EPAC convection/activity during the same timeframe, especially through the first half of September. So while I wouldn’t “cancel” the season per se, I think there is a good chance that it will underperform relative to expectations/forecasts. We shall see.

What's interesting imho is why a predicted La Nina year like 2021 would feature TUTTs, sinking air, coolish MDR, and so forth. Aren't these things you would see in a warm neutral or El Nino year?

[Shell Mound]

Watch as someone uses this as evidence that the season will be inactive

I could have sworn a while ago that the model was showing an MDR storm circa August 22.

The EPS, whether long-range or otherwise, tends to miss a lot of weak systems and marginal hurricanes, but it does well in terms of gauging the potential for intense activity. So I think it can be used to assess the potential for higher-end long-trackers during the peak of the season. In this case it agrees relatively well with the BoM’s ACCESS, the JMA, and the CFSv2 in suggesting a suppressed ITCZ, a strong TUTT, a fairly coolish MDR vs. the subtropics, and possible sinking air over the basin during the “traditional” peak. Also, the balance of the guidance suggests some additional VWS from EPAC convection/activity during the same timeframe, especially through the first half of September. So while I wouldn’t “cancel” the season per se, I think there is a good chance that it will underperform relative to expectations/forecasts. We shall see.

What's interesting imho is why a predicted La Nina year like 2021 would feature TUTTs, sinking air, coolish MDR, and so forth. Aren't these things you would see in a warm neutral or El Nino year?

I think AGW-related forcing and the -AMM/-AMO are compounding intra-seasonal variation and offsetting the otherwise conducive background (-PDO/-ENSO). Additionally, the tropical Pacific and Indian basins are considerably warmer than they were just a few decades ago. This, in turn, impacts downstream patterns and offsets relatively slower warming of the tropical Atlantic basin, especially with the far North Atlantic cooling considerably during the same timeframe, owing to AGW-related freshwater intrusion via Greenland-based ice-melt → weakening of the Atlantic THC → -AMM/-AMO.

[aspen]

The setup in the WPac looks like it’ll only allow for weak sloppy systems, and the models have really backed off with the potential strong EPac system that was originally forecast to start developing in a few days. If both Pacific basins end up being rather inactive like this for the next 1-2 weeks, it would probably lower the shear in the Atlantic and allow for activity in the tropics to start once the suppressive CCKW/MJO phase move out at the very end of July and the start of August.

[tolakram]

What's interesting imho is why a predicted La Nina year like 2021 would feature TUTTs, sinking air, coolish MDR, and so forth. Aren't these things you would see in a warm neutral or El Nino year?

TUTTs, especially in that location, are pretty common. I can't find a link between seasonal types, and some above average years had TUTTs that appeared in late August. Dorian formed in a TUTT year.

Welcome to cancel season. Here's an interesting paper on TUTTs and TC variability: https://www.pnas.org/content/117/37/22720

Zhuo Wang, Gan Zhang, Timothy J. Dunkerton, and Fei-Fei Jin
PNAS September 15, 2020 117 (37) 22720-22726; first published August 31, 2020

Although the SST and precipitation correlation maps strongly resemble the impacts of the ENSO (SI Appendix, Fig. S5), we stress that the variability of the summertime stationary waves or TUTTs cannot be completely attributed to the ENSO, which is much weaker in summer than in winter.

Their summary

Summary and Discussion
We demonstrated the strong link between TUTTs and TC activity over the North Pacific and North Atlantic. As part of the summertime stationary waves, TUTTs are related to tropical and extratropical SST and precipitation anomalies in various regions, including the ENSO and monsoons. Additionally, TUTTs are the preferred regions for RWB, and reflect the cumulative effects of RWB beyond the synoptic scale. Active RWB in a strong TUTT year contributes to enhanced VWS and reduced tropospheric humidity, and may help amplify the TUTT via the transient eddy feedback (28, 30). Radiative forcing associated with the changes in the humidity field may play a role in maintaining TUTTs as well (33). Our analysis suggests that stationary waves integrate tropical and extratropical impacts on TC activity and provide a hemispheric perspective on the variability of TC activity over the North Pacific and North Atlantic. In addition, the Atlantic TUTT and the Pacific TUTT tend to vary out of phase due to the PV impermeability nature, and the seesaw relationship of the Pacific and Atlantic TUTTs contributes to an anticorrelation of TC activity between the two basins, which makes the global TC activity less variable. Finally, because TUTTs are connected to monsoons and extratropical Rossby waves, they introduce a factor other than tropical SST for the variability of TC activity. Overall, this study advocates a hemispheric perspective that helps us understand the variability and predictability of TC activity over the North Atlantic and North Pacific. This view may also help us understand the projection of TC activity in future climate.

SEASON CANCEL!

[tolakram]

Here's the current Euro 200mb edit: (sorry, this is the GFS) vorticity to track the upper level low. In order to know if this will actually slow the season down we first have to have a developing wave that gets torn apart by a TUTT. Right now this just looks like a late July typical pattern, but of course I'm not a forecaster or tropical weather specialist.