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

[Shell Mound]

Most of the cooling in SSTs over the MDR and Caribbean has occurred since 20 April, per Tropical Tidbits’ data. I used ESRL’s plotting and analysis page to compare the change in MSLP, SST, and precipitation-rate (mm/h) anomalies during the period 20 April–1 May vs. the first nineteen days of April. I examined the region between 45°S–45°N and 120°W–40°E. Based on ESRL’s output, I found no significant change in any of these variables over the MDR and Caribbean, so USTropics’ explanation as to the cooling does not seem to hold, at least based on ESRL’s data. Therefore, the significant cooling is likely related to the AMO rather than convection, stronger high pressure, or other factors.

That's not how it works, the AMO can't just magically cool down the MDR. It needs help from other sources like trade wind variability or insolation fluxes. Problem is, the data isn't perfect. The SST data will have problems, missing areas and biases. In addition, the ESRL data isn't perfect as well, so it could be missing some things too. More likely there was a trade wind outbreak or a fall in insolation (SAL would do it and also make SST datasets overdo the fall). AMO variations are much more gradual than this, there have been tons of short term crashes like this even in the peak of the +AMO period.

Based on satellite data, the recent cooling does appear to be largely related to a recent, significant SAL outbreak—well within seasonal norms. If anything, the SST signature over the subtropical and even part of the far North Atlantic has become significantly more favourable over the past several weeks, with the overall look being much closer to a budding +AMO than it was a few months ago. Also, one can note a long-term southward shift in the warm tongue north of the MDR. So if one discards the recent SAL-related cooling over the MDR and Caribbean, the actual evolution over the past several weeks, coupled with the slow but steady +SOI trend and the persistent +IOD (hence enhanced rainfall over the equatorial Sahel due to a strong African monsoon), does not augur well for those hoping for an average or slightly-above-average Atlantic season. Indications are that we may well end up with La Niña conditions and a corresponding -PDO by the peak of the Atlantic season. So the risk of a hyperactive season with steering currents favouring landfalls seems to be increasing.

[toad strangler]

The hype for this season seems a little over the top. Even if it's busy, and last I checked season predictions are not all that good, we don't know how many, if any, will impact land. Hope for the best, prepare for the worst!

I don't see any hype. All I see are Indicators.

[cycloneye]

Most of the cooling in SSTs over the MDR and Caribbean has occurred since 20 April, per Tropical Tidbits’ data. I used ESRL’s plotting and analysis page to compare the change in MSLP, SST, and precipitation-rate (mm/h) anomalies during the period 20 April–1 May vs. the first nineteen days of April. I examined the region between 45°S–45°N and 120°W–40°E. Based on ESRL’s output, I found no significant change in any of these variables over the MDR and Caribbean, so USTropics’ explanation as to the cooling does not seem to hold, at least based on ESRL’s data. Therefore, the significant cooling is likely related to the AMO rather than convection, stronger high pressure, or other factors.

That's not how it works, the AMO can't just magically cool down the MDR. It needs help from other sources like trade wind variability or insolation fluxes. Problem is, the data isn't perfect. The SST data will have problems, missing areas and biases. In addition, the ESRL data isn't perfect as well, so it could be missing some things too. More likely there was a trade wind outbreak or a fall in insolation (SAL would do it and also make SST datasets overdo the fall). AMO variations are much more gradual than this, there have been tons of short term crashes like this even in the peak of the +AMO period.

Based on satellite data, the recent cooling does appear to be largely related to a recent, significant SAL outbreak—well within seasonal norms. If anything, the SST signature over the subtropical and even part of the far North Atlantic has become significantly more favourable over the past several weeks, with the overall look being much closer to a budding +AMO than it was a few months ago. Also, one can note a long-term southward shift in the warm tongue north of the MDR. So if one discards the recent SAL-related cooling over the MDR and Caribbean, the actual evolution over the past several weeks, coupled with the slow but steady +SOI trend and the persistent +IOD (hence enhanced rainfall over the equatorial Sahel due to a strong African monsoon), does not augur well for those hoping for an average or slightly-above-average Atlantic season. Indications are that we may well end up with La Niña conditions and a corresponding -PDO by the peak of the Atlantic season. So the risk of a hyperactive season with steering currents favouring landfalls seems to be increasing.

The evidence keeps mounting for a very active season so good that you finnally see it. The ENSO Thread says it all.

[galaxy401]

I wonder if the Gulf of Mexico will see a cooldown through the month of May. Most of the eastern half of the USA is seeing unusually cold weather right now and I wonder if that contribute to the region cooling down as well.

[psyclone]

The hype for this season seems a little over the top. Even if it's busy, and last I checked season predictions are not all that good, we don't know how many, if any, will impact land. Hope for the best, prepare for the worst!

This is a great point. Recall the hysteria the preceded the 2006 season after the nightmare that was 2005. To be fair it does look active. But sometimes the consensus is wrong

[TheStormExpert]

I wonder if the Gulf of Mexico will see a cooldown through the month of May. Most of the eastern half of the USA is seeing unusually cold weather right now and I wonder if that contribute to the region cooling down as well.

The Gulf of Mexico is cooling as a result. Regardless it is still warm enough to support TC development, I’m sure I’m the summer months once these fronts stop coming as far south as they’re it’ll quickly rebound, so no problems there in terms of lack of service warmth.

[HurricaneEnzo]

I wonder if the Gulf of Mexico will see a cooldown through the month of May. Most of the eastern half of the USA is seeing unusually cold weather right now and I wonder if that contribute to the region cooling down as well.

The Gulf of Mexico is cooling as a result. Regardless it is still warm enough to support TC development, I’m sure I’m the summer months once these fronts stop coming as far south as they’re it’ll quickly rebound, so no problems there in terms of lack of service warmth.

Yeah I would probably expect to see some slight cooling throughout most of May. While still out in fantasy land models are indicating once we get past this cool spell in mid-May the torch is going to return towards the end of the month. If that does happen things have plenty of time to get warmed up for peak season. This prolonged cool could help keep some of those early season junk systems at bay maybe.

[toad strangler]

The hype for this season seems a little over the top. Even if it's busy, and last I checked season predictions are not all that good, we don't know how many, if any, will impact land. Hope for the best, prepare for the worst!

This is a great point. Recall the hysteria the preceded the 2006 season after the nightmare that was 2005. To be fair it does look active. But sometimes the consensus is wrong

Who is hyping anything? Is he talking about some of the pre season pro outlooks or the posts on this forum?

[TheStormExpert]

I wonder if the Gulf of Mexico will see a cooldown through the month of May. Most of the eastern half of the USA is seeing unusually cold weather right now and I wonder if that contribute to the region cooling down as well.

The Gulf of Mexico is cooling as a result. Regardless it is still warm enough to support TC development, I’m sure I’m the summer months once these fronts stop coming as far south as they’re it’ll quickly rebound, so no problems there in terms of lack of service warmth.

Yeah I would probably expect to see some slight cooling throughout most of May. While still out in fantasy land models are indicating once we get past this cool spell in mid-May the torch is going to return towards the end of the month. If that does happen things have plenty of time to get warmed up for peak season. This prolonged cool could help keep some of those early season junk systems at bay maybe.

Yeah there are indications that later this month the pattern flips to less troughiness in the Eastern U.S. and maybe more ridging which will likely cut off the fronts from passing into or even close to the Gulf of Mexico or northern Gulf Coast. Still may have to watch out for potential systems to spin up from the Central America Gyre late-May into early-June.

[TheStormExpert]

The hype for this season seems a little over the top. Even if it's busy, and last I checked season predictions are not all that good, we don't know how many, if any, will impact land. Hope for the best, prepare for the worst!

This is a great point. Recall the hysteria the preceded the 2006 season after the nightmare that was 2005. To be fair it does look active. But sometimes the consensus is wrong

Who is hyping anything? Is he talking about some of the pre season pro forecasts or the posts on this forum?

He’s referring to how people were over-hyping the 2006 Atlantic season in that spring thanks to the recent activity in 2004/2005 which busted big time thanks to a moderate El Niño that summer.

Obviously no one is overhyping anything this year with what’s all going on especially considering there are NO indications of an El Niño.

[TheStormExpert]

Most of the cooling in SSTs over the MDR and Caribbean has occurred since 20 April, per Tropical Tidbits’ data. I used ESRL’s plotting and analysis page to compare the change in MSLP, SST, and precipitation-rate (mm/h) anomalies during the period 20 April–1 May vs. the first nineteen days of April. I examined the region between 45°S–45°N and 120°W–40°E. Based on ESRL’s output, I found no significant change in any of these variables over the MDR and Caribbean, so USTropics’ explanation as to the cooling does not seem to hold, at least based on ESRL’s data. Therefore, the significant cooling is likely related to the AMO rather than convection, stronger high pressure, or other factors.

That's not how it works, the AMO can't just magically cool down the MDR. It needs help from other sources like trade wind variability or insolation fluxes. Problem is, the data isn't perfect. The SST data will have problems, missing areas and biases. In addition, the ESRL data isn't perfect as well, so it could be missing some things too. More likely there was a trade wind outbreak or a fall in insolation (SAL would do it and also make SST datasets overdo the fall). AMO variations are much more gradual than this, there have been tons of short term crashes like this even in the peak of the +AMO period.

Based on satellite data, the recent cooling does appear to be largely related to a recent, significant SAL outbreak—well within seasonal norms. If anything, the SST signature over the subtropical and even part of the far North Atlantic has become significantly more favourable over the past several weeks, with the overall look being much closer to a budding +AMO than it was a few months ago. Also, one can note a long-term southward shift in the warm tongue north of the MDR. So if one discards the recent SAL-related cooling over the MDR and Caribbean, the actual evolution over the past several weeks, coupled with the slow but steady +SOI trend and the persistent +IOD (hence enhanced rainfall over the equatorial Sahel due to a strong African monsoon), does not augur well for those hoping for an average or slightly-above-average Atlantic season. Indications are that we may well end up with La Niña conditions and a corresponding -PDO by the peak of the Atlantic season. So the risk of a hyperactive season with steering currents favouring landfalls seems to be increasing.

What happen to your optimistic predictions from the other day?

[toad strangler]

This is a great point. Recall the hysteria the preceded the 2006 season after the nightmare that was 2005. To be fair it does look active. But sometimes the consensus is wrong

Who is hyping anything? Is he talking about some of the pre season pro forecasts or the posts on this forum?

He’s referring to how people were over-hyping the 2006 Atlantic season in that spring thanks to the recent activity in 2004/2005 which busted big time thanks to a moderate El Niño that summer.

Obviously no one is overhyping anything this year with what’s all going on especially considering there are NO indications of an El Niño.

I wasn't on this forum 14 years ago so I can't speak for that. All I can say is that I don't see any hype. I see feedback on some very bullish indicators for sure. Is that hype? Don't know about all that but I digress.... back to Indicators

[weathaguyry]

Even though the MDR is cooling, the Subtropics off the East Coast are also cooling. I believe the MDR anomalies usually fluctuate around this time of year due to strong trades and SAL outbreaks causing upwelling. However, the Subtropics off the East Coast should be in a warming trend this time of year, but they are cooling since there has been cold outbreaks moving off the East Coast. Perhaps this could be a factor that stops the subtropics from outperforming the tropics this year, and this also may help the AMO take more of a + appearance as we go into hurricane season. Just throwing in my 2 cents here, obviously SSTs are always fluctuating and The Atlantic may look very different by August and September.

[tolakram]

The hype about my post about the hype seems a little over the top.

I'm talking about some of the tweets. I should have been very clear, I don't think anyone here is hyping, the discussion is good.

My personal view is we have no idea whatsoever, beyond a few slight hints, how bad the season will be.

[SFLcane]

https://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta7diff_global_1.png

Even though the MDR is cooling, the Subtropics off the East Coast are also cooling. I believe the MDR anomalies usually fluctuate around this time of year due to strong trades and SAL outbreaks causing upwelling. However, the Subtropics off the East Coast should be in a warming trend this time of year, but they are cooling since there has been cold outbreaks moving off the East Coast. Perhaps this could be a factor that stops the subtropics from outperforming the tropics this year, and this also may help the AMO take more of a + appearance as we go into hurricane season. Just throwing in my 2 cents here, obviously SSTs are always fluctuating and The Atlantic may look very different by August and September.

The Pacific is heading towards La Niña no doubt about that. Conditions across the Atlantic could be quite favorable to say the least come August.

Edit; after looking at the May euro it’s not as favorable as it looked the previous month for the Atlantic. 1973, 2012 are pretty extreme examples of a la Niña not amounting to much. Just going with the euro which as a whole is usually the best model it’s showing a near average season IF it’s right.

[SFLcane]

Phil k in his June update will likely account for the cooling in the Atlantic if it persists.

[cycloneye]

Phil k in his June update will likely account for the cooling in the Atlantic if it persists.

But he wrote this twit on May 4th.

 https://twitter.com/philklotzbach/status/1257340716637925382

[SFLcane]

Phil k in his June update will likely account for the cooling in the Atlantic if it persists.

But he wrote this twit on May 4th.

https://twitter.com/philklotzbach/status/1257340716637925382

Hi Luis, The Euro cools from that look.

[TheStormExpert]

Season cancel posts already!? It’s not even June 1st!

[jconsor]

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.