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

[USTropics]

Also the notion the MDR is cooling is simply false if we're going by simply sea surface skins:



This is reflected in the 7-day SST trend animation below:


Depending on which data set you're using, we're slightly above or below the climo average baseline in the MDR:





We are starting at a lower base compared to hyperactive years at this point, so those type of strong MDR signals are not present currently. This is not an unfavorable look either, so to say the season will bust based on the current SST configuration would be premature.

[USTropics]

This was from 2020, but is just as important for this year:

 https://twitter.com/philklotzbach/status/1266107330417979392

[Shell Mound]

This was from 2020, but is just as important for this year:

https://twitter.com/philklotzbach/status/1266107330417979392

Overall, based on monthly OISSTv2 data to date (image at middle), there seems to be a weakly positive signal for enhanced activity, but not to the degree that CSU is forecasting. The SST gradient is more zonal than meridional so far, befitting EOF2 +AMO (image at bottom). That is why I think a slightly-above-average season with ACE of ~120 or so is more likely than a season with ACE ≥ 150, given that the EOF2 signature is taking its time to transition to EOF1. A similar situation, if I recall, existed in 2019 and the EOF2 +AMO never completed its transition to EOF1 +AMO by ASO.

[toad strangler]

Also the notion the MDR is cooling is simply false if we're going by simply sea surface skins:

Handwringing, just like with SAL. It's quite entertaining TBH. You would think the MDR has icebergs floating around in it. In reality, it's a tik off with 3 months to go.

[SFLcane]

Yeah we're running behind 2020 and 2017 but not as cool as say 2018. Seems reasonable to expect an active season but not hyperactive maybe.

[Category5Kaiju]

So maybe I think the important question here would be are there common distinguishing early indications of a to-be hyperactive season versus a to-be above average season and how 2021 fits into the hyperactive or above average comparisons. I am no expert on this and perhaps somebody else may have better ideas on this, but I do wonder if there are any early tangible indicators common and unique to all hyperactive seasons...

[toad strangler]

Yeah we're running behind 2020 and 2017 but not as cool as say 2018. Seems reasonable to expect an active season but not hyperactive maybe.

Whatever storms are going to form are going to form regardless if SST's are a hair or two below "normal". So perhaps ACE could be effected but I don't buy for a second that storms just won't appear because SST's are a bit off. If this season come in under projection it will be for multiple reasons above and beyond SST's

[SFLcane]

Yeah we're running behind 2020 and 2017 but not as cool as say 2018. Seems reasonable to expect an active season but not hyperactive maybe.

Whatever storms are going to form are going to form regardless if SST's are a hair or two below "normal". So perhaps ACE could be effected but I don't buy for a second that storms just won't appear because SST's are a bit off. If this season come in under projection it will be for multiple reasons above and beyond SST's

Yeah although SST affects stability too. That's gonna hinder the season until ~August probably.

[Category5Kaiju]

If I am not mistaken last year was in a way hindered until August too, like we did not get out first major hurricane until the end of August and I specifically recall people yelling "season cancelled" in July and early August because they thought the SAL would ruin the entire season. Heck, 2017-2019 were also in a way hindered until August once Harvey, Florence, and Dorian occurred. So my overall point is, if we simple were to look at sst anomalies as the deciding factor in this season's activity (it isn't, but just as a theoretical thought process), assuming there indeed is a gradual warmup until the ASO timeframe, this season if anything could be a backloaded one. Sure, we may not get major July hurricanes, but how many seasons in the recent past have featured this anyways (we get it 2005, you were just going crazy back then )?

An additional point I would like to make is if I am also not mistaken, 2020 may have had warmer sst anomalies than 2021, but one thing I believe is working in 2021's favor is that the SAL is not as potent and extensive as it was at this point in time last year.

[tolakram]

I've had to move some useless posts into the moderation room. Please, it's not ok to make fun of others just because you don't like an opinion. If you replied to one of these your post is probably gone as well. Don't worry, but it's a good time for this friendly reminder:

If you have an issue with a post and think it violates S2K rules report it. Yes, every year we go through the same thing with SST's and SAL and no storms until August, and season cancel. It's all part of the conversation, and is only a problem if it's obviously trolling.

Thanks.

[toad strangler]

Ben Noll acknowledging the SST change in May over 2020 but doesn't say anything about it's significance. Which I don't think is much at this point. Again, these are anomalies and I just don't see anything about this signature that says anything other than the warmer anomalies are in the sub tropics. Meat of the season still nearly 2.5 months out from beginning. Something to keep an eye on for sure.
 http://twitter.com/BenNollWeather/status/1397945440809754634

[HurricaneEnzo]

Ben Noll acknowledging the SST change in May over 2020 but doesn't say anything about it's significance. Which I don't think is much at this point. Again, these are anomalies and I just don't see anything about this signature that says anything other than the warmer anomalies are in the sub tropics. Meat of the season still nearly 2.5 months out from beginning. Something to keep an eye on for sure.
http://twitter.com/BenNollWeather/status/1397945440809754634?s=20

Looking at the map he is using I honestly don't see any massive differences. Yes the MDR is slightly cooler and Sub-tropics slightly warmer but I wouldn't say it is an absurd level of difference. I would say the EPAC looks better for Atlantic activity than 2020 as it is cooler over a larger area. Yeah last year overall might be a little better look but I don't see anything that looks like much of a deterrent for this season as it currently stands (strictly looking at SSTs). Still think we are looking at an active season just not 30 named storms active.

[Shell Mound]

With the MJO entering a low amplitude in Phase 7/8 over the next few weeks, this should be and already is promoting prolonged low-level westerlies over the MDR. Seven-day CDAS trends are finally showing substantial warming setting in over the past few days, just as the 850-mb westerlies (U-anomalies or zonal winds) have begun to kick in on the Hovmöller diagram(s). More importantly, the mid-latitude or subtropical Atlantic has been steadily cooling over the past week and a half, which supports further warming over the MDR, in line with CFSv2 forecasts for early June. Given the increasing likelihood of cool neutral ENSO persisting through ASO, with the warmest anomalies being concentrated near the IDL vs. Niño 1+2, I think I am finally beginning to sign onto the likelihood of a potentially hyperactive season, and have adjusted my seasonal forecast accordingly. A busy Atlantic season looks more and more likely.



On another note, some forecasters are already “sounding the alarm” about 2021 possibly being to peninsular Florida what 2020 was to Louisiana:

But a shift in upper-air patterns over the United States has one leading meteorologist concerned the Bermuda-Azores high will forsake its 2020 stronghold in the western Atlantic – a move that could leave Florida more vulnerable to a tropical attack from the east.

Dan Kottlowski, a senior hurricane forecaster at the Pennsylvania-based AccuWeather...

“The Bermuda High will still nose into the Gulf of Mexico but we don’t think it will do it nearly as frequently,” Kottlowski said. “All we’re saying is that it's a more dangerous pattern for the East Coast.” ...

...National Hurricane Center Director Ken Graham said he is concerned Florida’s reputation as being stormproof last year may lead to a false sense of security.

He has been questioned enough about the lack of tropical cyclones hitting Florida that he made a graphic to show how the state would have faired had the Bermuda High been more to the east, similar to what AccuWeather is predicting.



Instead of Louisiana being in 2020's tropical crosshairs, it would have been Florida with storm landfalls or hurricane-force winds ripping into Panama City, Tampa, Miami and Jacksonville.

“If the community thinks it wasn’t too bad for us last year, well, it wouldn’t take much of a change for that to be very different,” Graham said during a May hurricane preparation meeting. “Think about the high pressure in the Atlantic moving east and then Florida is in the way.”

Climate and weather modelers at the University of Miami's Rosenstiel School of Marine and Atmospheric Science are studying the movement of the Bermuda High, including how it is reacting to the slowing of the Gulf Stream current in reaction to climate change. ...

UM professor Ben Kirtman said a slower Gulf Stream is correlating with a westerly movement of the Bermuda high that could mean more rain for the southeast United States.

More information:

“Florida got really lucky last year given how many storms were out there,” Klotzbach said. “But now the big concern is that one of these storms is going to actually hit a major metropolitan area and cause massive amounts of damage.

“That’s especially the case for Tampa-St. Petersburg, which is so, so prone to storm surge.”

[SFLcane]

 https://twitter.com/hurricanemanwx/status/1398718560801890314

[DorkyMcDorkface]

 https://twitter.com/WxTca/status/1399038129076592644

[aspen]

Took longer than anticipated, but the MDR is clearly warming up. While still a little cooler than normal, SSTs are indeed rising, and the 7-day anomaly change map shows warming throughout much of the MDR, Caribbean, and Gulf.

[cycloneye]

 https://twitter.com/JimCantore/status/1399368774847844355

[JetFuel_SE]

Took longer than anticipated, but the MDR is clearly warming up. While still a little cooler than normal, SSTs are indeed rising, and the 7-day anomaly change map shows warming throughout much of the MDR, Caribbean, and Gulf.
https://i.imgur.com/z3Gq6dG.png
https://i.imgur.com/CEt7ivP.png
https://i.imgur.com/XNL8XRo.png

It's not really colder than average, CDAS has a cold bias, at least in the MDR.

[toad strangler]

Took longer than anticipated, but the MDR is clearly warming up. While still a little cooler than normal, SSTs are indeed rising, and the 7-day anomaly change map shows warming throughout much of the MDR, Caribbean, and Gulf.
https://i.imgur.com/z3Gq6dG.png
https://i.imgur.com/CEt7ivP.png
https://i.imgur.com/XNL8XRo.png

It's not really colder than average, CDAS has a cold bias, at least in the MDR.

And it didn't take longer than anticipated either. There is next to nothing amiss with MDR SST's in relation to average. There hasn't been. I think people get fooled by the negative blue colors of a anomaly map and react like it's far too cool when temps are just off by fractions in reality.

[SFLcane]

It would be an interesting dig to look up ridges and front maps from late May in 2004. Florida’s rainy season started on the late side. Interested to look up NWS Miami AFDs from late May in 2004. Obviously nothing scientific in nature but definitely some similarities.