2020 Indicators: SST's / SAL / MSLP / Steering / Shear / Instability / Sat Images

[cycloneye]

No need for sesaon cancel posts.

 https://twitter.com/BenNollWeather/status/1258030002437632001

[USTropics]

I would recommend using a blend of models, there are too many known biases in each model's seasonal forecasts to accurately use one. The C3S multi-system uses a blend of 5 model data sets: ARPEGE (meteo-france's climate model), ECMWF, UKMET, DWD (German model), and NCEP (GFS/CFS data). Here is the JAS blend:



SSTA mean for all ensembles of 5 models:


You can find these products (along with others), individual model runs, and NINO plumes here - https://climate.copernicus.eu/charts/c3s_seasonal/

[SFLcane]

No need for sesaon cancel posts.

https://twitter.com/BenNollWeather/status/1258030002437632001

Luis, 0.8*100 ACE = 80 ACE looks A cool AMO look like that will really dampen things. Euro tends to underdo things, but last month was showing near average. So it's trending weaker

[SFLcane]

I would recommend using a blend of models, there are too many known biases in each model's seasonal forecasts to accurately use one. The C3S multi-system uses a blend of 5 model data sets: ARPEGE (meteo-france's climate model), ECMWF, UKMET, DWD (German model), and NCEP (GFS/CFS data). Here is the JAS blend:

https://i.imgur.com/vWyWVr9.png

SSTA mean for all ensembles of 5 models:
https://i.imgur.com/YKBxpPc.png

You can find these products (along with others), individual model runs, and NINO plumes here - https://climate.copernicus.eu/charts/c3s_seasonal/

That's a month old for the Euro. It had a warm MDR last month. That has changed.

[TheStormExpert]

ECMWF appears to be too cool for the MDR for May 2020 vs. current SSTs, unless there is a significant cooling rest of May.

Also the SSTs forecast from ECMWF doesn't show much change in most of the MDR from May to Sep. The significant cooling is mainly from the far northern Caribbean into the subtropical Atlantic.

https://ibb.co/CBfHXg2
https://ibb.co/h7jPTyJ
https://ibb.co/HtnLGvn
https://ibb.co/RCkTZqs

Your images you posted aren’t showing up, do you mind reposting them? Thanks!

[USTropics]

I would recommend using a blend of models, there are too many known biases in each model's seasonal forecasts to accurately use one. The C3S multi-system uses a blend of 5 model data sets: ARPEGE (meteo-france's climate model), ECMWF, UKMET, DWD (German model), and NCEP (GFS/CFS data). Here is the JAS blend:

https://i.imgur.com/vWyWVr9.png

SSTA mean for all ensembles of 5 models:
https://i.imgur.com/YKBxpPc.png

You can find these products (along with others), individual model runs, and NINO plumes here - https://climate.copernicus.eu/charts/c3s_seasonal/

That's a month old for the Euro. It had a warm MDR last month. That has changed.

It's a blend of 5 models (and yes it updates on the 13th, so still using last month's data). I'm not seeing much change though in the latest ECMWF. Anomalies are either slightly warm or dead even for September:

(this was posted on Twitter, so think its fine to post here)

[SFLcane]

I would recommend using a blend of models, there are too many known biases in each model's seasonal forecasts to accurately use one. The C3S multi-system uses a blend of 5 model data sets: ARPEGE (meteo-france's climate model), ECMWF, UKMET, DWD (German model), and NCEP (GFS/CFS data). Here is the JAS blend:

https://i.imgur.com/vWyWVr9.png

SSTA mean for all ensembles of 5 models:
https://i.imgur.com/YKBxpPc.png

You can find these products (along with others), individual model runs, and NINO plumes here - https://climate.copernicus.eu/charts/c3s_seasonal/

That's a month old for the Euro. It had a warm MDR last month. That has changed.

It's a blend of 5 models (and yes it updates on the 13th, so still using last month's data). I'm not seeing much change though in the latest ECMWF. Anomalies are either slightly warm or dead even for September:

(this was posted on Twitter, so think its fine to post here)
https://i.imgur.com/WAGNoCb.png

Hi UStropics, What about August? Remember it's the North/south gradient that matters too. If the mid latitude Atlantic is warm while the MDR is cool or even average, it weakens the Hadley Cell and increases stability.

[TheStormExpert]

If the Euro Seasonal Outlooks for the Atlantic were true we would have seen below average hurricane seasons the last 3-4 years. Obviously that wasn’t the case so all in all the Euro showing 80% of normal ACE for the Atlantic Hurricane Season and a developing La Niña is not a good sign to me.

[cycloneye]

 https://twitter.com/hurricanetrack/status/1258070090257510403

[USTropics]

That's a month old for the Euro. It had a warm MDR last month. That has changed.

It's a blend of 5 models (and yes it updates on the 13th, so still using last month's data). I'm not seeing much change though in the latest ECMWF. Anomalies are either slightly warm or dead even for September:

(this was posted on Twitter, so think its fine to post here)
https://i.imgur.com/WAGNoCb.png

Hi UStropics, What about August? Remember it's the North/south gradient that matters too. If the mid latitude Atlantic is warm while the MDR is cool or even average, it weakens the Hadley Cell and increases stability.

Due to it being a commercial product, I can't post the August image. I can say it is slightly warmer than the September SSTA config. I do have permission to post the latest ASO for the newest ECMWF forecast from yesterday though:


Again this is just one model, which has known biases in the Atlantic MDR and across the tropical regions to take into account. I would still strongly recommend using a blend of at least 3-5 models (and preferably ensemble members). Another aspect I noticed with the latest ECMWF ensembles, is an increase in precipitation across the MDR (particularly far eastern Atlantic). This is likely contributing to some of the cooling from the model forecast (I can't post the current forecast, but I can post last months, which is very similar):

[SFLcane]

It's a blend of 5 models (and yes it updates on the 13th, so still using last month's data). I'm not seeing much change though in the latest ECMWF. Anomalies are either slightly warm or dead even for September:

(this was posted on Twitter, so think its fine to post here)
https://i.imgur.com/WAGNoCb.png

Hi UStropics, What about August? Remember it's the North/south gradient that matters too. If the mid latitude Atlantic is warm while the MDR is cool or even average, it weakens the Hadley Cell and increases stability.

Due to it being a commercial product, I can't post the August image. I can say it is slightly warmer than the September SSTA config. I do have permission to post the latest ASO for the newest ECMWF forecast from yesterday though:
https://i.imgur.com/zS6m24y.png

Again this is just one model, which has known biases in the Atlantic MDR and across the tropical regions to take into account. I would still strongly recommend using a blend of at least 3-5 models (and preferably ensemble members). Another aspect I noticed with the latest ECMWF ensembles, is an increase in precipitation across the MDR (particularly far eastern Atlantic). This is likely contributing to some of the cooling from the model forecast (I can't post the current forecast, but I can post last months, which is very similar):

https://i.imgur.com/O0MAH13.png

Hmmm...I don't think more precip is not gonna cause cooling.That's enhanced trade winds.

[USTropics]

I'm not seeing enhanced trade winds at peak season being an issue, quite the opposite. I'm going to use the CFS forecast model for this (free and a slightly better product verification). This was the May forecast, and we're definitely seeing enhanced trade winds across the MDR all the way to Africa currently. The combination of stronger anomalous southeasterly winds and enhanced pressure gradient has caused upwelling, as you can see in the 200mb zonal wind charts and outlined in my posts last week:


Pretty easy to see why as well, a huge subtropical high pressure area has been setup across the central NATL at an anomalously lower latitude for this time of year, enhancing the pressure gradient:


As we move into July and August, things begin to change. First the high pressure area begins to flatten out and lifts north and away from the equator (lessening the pressure gradient between the ITCZ).


The zonal wind pattern will also respond to this:


To compare to active season composite (using 10 years that were active early):


Nonactive season composite:

[USTropics]

Some other cool things you can do with Copernicus (implemented by ECMWF - https://climate.copernicus.eu/charts/c3 ... rea=area08) is look at probability density function (PDF) forecasts. You can compare the April run of the 51 ECMWF ensemble members with the corresponding model climate PDF, which take into account the hindcast set.



Essentially this is stating there is a 70-100% probability of the MDR being in the top 20% of warmest climatological years selected, compared to previous verifications/hindcasts of ECMWF forecasts. We'll see how this changes on the 13th when the latest ECMWF data for May gets inputted, but not seeing much change on Weatherbell between forecasts to change this.

[SFLcane]

Some other cool things you can do with Copernicus (implemented by ECMWF - https://climate.copernicus.eu/charts/c3 ... rea=area08) is look at probability density function (PDF) forecasts. You can compare the April run of the 51 ECMWF ensemble members with the corresponding model climate PDF, which take into account the hindcast set.

https://i.imgur.com/GkCjMvi.png

Essentially this is stating there is a 70-100% probability of the MDR being in the top 20% of warmest climatological years selected, compared to previous verifications/hindcasts of ECMWF forecasts. We'll see how this changes on the 13th when the latest ECMWF data for May gets inputted, but not seeing much change on Weatherbell between forecasts to change this.

Looks like a -AMO to me.

[CyclonicFury]

Some other cool things you can do with Copernicus (implemented by ECMWF - https://climate.copernicus.eu/charts/c3 ... rea=area08) is look at probability density function (PDF) forecasts. You can compare the April run of the 51 ECMWF ensemble members with the corresponding model climate PDF, which take into account the hindcast set.

https://i.imgur.com/GkCjMvi.png

Essentially this is stating there is a 70-100% probability of the MDR being in the top 20% of warmest climatological years selected, compared to previous verifications/hindcasts of ECMWF forecasts. We'll see how this changes on the 13th when the latest ECMWF data for May gets inputted, but not seeing much change on Weatherbell between forecasts to change this.

Looks like a -AMO to me.

MDR SSTAs are far more important than the far North Atlantic SSTAs. The warm subtropics have been persistent over the past few years, and it hasn't dampened MDR activity very much.

[SFLcane]

I'm not seeing enhanced trade winds at peak season being an issue, quite the opposite. I'm going to use the CFS forecast model for this (free and a slightly better product verification). This was the May forecast, and we're definitely seeing enhanced trade winds across the MDR all the way to Africa currently. The combination of stronger anomalous southeasterly winds and enhanced pressure gradient has caused upwelling, as you can see in the 200mb zonal wind charts and outlined in my posts last week:
https://i.imgur.com/TkaJBr2.png

Pretty easy to see why as well, a huge subtropical high pressure area has been setup across the central NATL at an anomalously lower latitude for this time of year, enhancing the pressure gradient:
https://i.imgur.com/kDvZ1Gu.png

As we move into July and August, things begin to change. First the high pressure area begins to flatten out and lifts north and away from the equator (lessening the pressure gradient between the ITCZ).
https://i.imgur.com/BeViT4U.png

The zonal wind pattern will also respond to this:
https://i.imgur.com/2Z6PJRz.png

To compare to active season composite (using 10 years that were active early):
https://i.imgur.com/w6C5BYV.png

Nonactive season composite:
https://i.imgur.com/XaC3j4p.png

Upper level winds look favorable because of La Niña. Worried about stability.

[SFLcane]

Some other cool things you can do with Copernicus (implemented by ECMWF - https://climate.copernicus.eu/charts/c3 ... rea=area08) is look at probability density function (PDF) forecasts. You can compare the April run of the 51 ECMWF ensemble members with the corresponding model climate PDF, which take into account the hindcast set.

https://i.imgur.com/GkCjMvi.png

Essentially this is stating there is a 70-100% probability of the MDR being in the top 20% of warmest climatological years selected, compared to previous verifications/hindcasts of ECMWF forecasts. We'll see how this changes on the 13th when the latest ECMWF data for May gets inputted, but not seeing much change on Weatherbell between forecasts to change this.

Looks like a -AMO to me.

MDR SSTAs are far more important than the far North Atlantic SSTAs. The warm subtropics have been persistent over the past few years, and it hasn't dampened MDR activity very much.

We didn't get any big MDR storms outside of Dorian the last two years. We're cooler than 2017.

[CyclonicFury]

Looks like a -AMO to me.

MDR SSTAs are far more important than the far North Atlantic SSTAs. The warm subtropics have been persistent over the past few years, and it hasn't dampened MDR activity very much.

We didn't get any big MDR storms outside of Dorian the last two years. We're cooler than 2017.

I was talking about MDR activity in general, not just storms that threatened land. 2018 had Beryl, Florence, Helene and Isaac. 2019 also had Jerry and Lorenzo. Aside from Florence, these storms either recurved (Helene, Lorenzo) or encountered strong shear near 60W (Beryl, Isaac, Jerry). Shear should be much weaker over the Caribbean this year.

[Chris90]

No big storms in the MDR besides Dorian the past 2 years?

I've got Florence on line 1, and Lorenzo on line 2.

[CyclonicFury]

:uarrow: No big storms in the MDR besides Dorian the past 2 years?

I've got Florence on line 1, and Lorenzo on line 2.

Interestingly Dorian wasn't even a hurricane while it was in the MDR. But what Dorian does show you is the systems that remain weak while in the MDR often pose a greater threat to land.

Both Florence and Lorenzo became strong unusually far east over the basin.

Regardless, the main takeaway is 2020, "on paper" looks more favorable than the last two seasons, both of which ended up above average.