2024 Indicators: SST's, MSLP, Shear, SAL, Steering, Instability (Day 16+ Climate Models)

[TheAustinMan]

Josh has a point about closer to land sst's.

https://twitter.com/iCyclone/status/1766584784136847475

Andy and Danny replied that MDR SSTAs have much stronger correlation with seasonal activity than Caribbean and Gulf:
https://twitter.com/dmorris9661/status/1766587386954190898?s=19

In addition, Caribbean and Gulf SSTAs (especially the latter) can fluctuate very quickly due to shallower waters, so we have little idea how they will look in August. MDR SSTAs are comparatively more stable, to the point where it's not too early to speculate.

The GOM and western Caribbean will support major hurricanes every hurricane season, it's more a matter of when they will warm up vs if. Like Teban stated, the shallow waters in this region make them susceptible to quick transitions of cooling and warming due to local parameters. Since we've been locked into an El Nino pattern for most of winter, with the jet stream positioned further south and numerous low pressure systems developing in the GOM, this has caused cooling. You can see from similar El Nino years that this is a common theme in the GOM and NW Caribbean (and why this has 0 correlation to predicting activity during the hurricane season):
https://i.imgur.com/Z39qQhb.jpeg

Indeed, any correlation between sea surface temperatures in the earliest part of the year in the Western Atlantic or Eastern Pacific with Atlantic seasonal activity is very tenuous. The strongest correlations -- albeit still modest at best -- are over in the equatorial Atlantic. And while we're still quite far out from hurricane season, the strongest correlations between sea surface temperature anomalies and ACE in the Gulf of Mexico are actually not found in the Gulf of Mexico (which fluctuates rapidly as aforementioned), but in the tropical Atlantic. Once storms get going, SSTs and oceanic heat content where storms trek are important factors for storm intensity, but from a seasonal activity perspective, MDR SST anomalies are king as far as SST correlations are concerned, and that's true both at the current long-range and during the hurricane season itself.

Source: Me, using ERSSTv5 for sea surface temperatures and IBTrACS for ACE

[Teban54]

Andy and Danny replied that MDR SSTAs have much stronger correlation with seasonal activity than Caribbean and Gulf:
https://twitter.com/dmorris9661/status/1766587386954190898?s=19

In addition, Caribbean and Gulf SSTAs (especially the latter) can fluctuate very quickly due to shallower waters, so we have little idea how they will look in August. MDR SSTAs are comparatively more stable, to the point where it's not too early to speculate.

The GOM and western Caribbean will support major hurricanes every hurricane season, it's more a matter of when they will warm up vs if. Like Teban stated, the shallow waters in this region make them susceptible to quick transitions of cooling and warming due to local parameters. Since we've been locked into an El Nino pattern for most of winter, with the jet stream positioned further south and numerous low pressure systems developing in the GOM, this has caused cooling. You can see from similar El Nino years that this is a common theme in the GOM and NW Caribbean (and why this has 0 correlation to predicting activity during the hurricane season):
https://i.imgur.com/Z39qQhb.jpeg

Indeed, any correlation between sea surface temperatures in the earliest part of the year in the Western Atlantic or Eastern Pacific with Atlantic seasonal activity is very tenuous. The strongest correlations -- albeit still modest at best -- are over in the equatorial Atlantic. And while we're still quite far out from hurricane season, the strongest correlations between sea surface temperature anomalies and ACE in the Gulf of Mexico are actually not found in the Gulf of Mexico (which fluctuates rapidly as aforementioned), but in the tropical Atlantic. Once storms get going, SSTs and oceanic heat content where storms trek are important factors for storm intensity, but from a seasonal activity perspective, MDR SST anomalies are king as far as SST correlations are concerned, and that's true both at the current long-range and during the hurricane season itself.

Source: Me, using ERSSTv5 for sea surface temperatures and IBTrACS for ACE
https://i.imgur.com/gRIvyeG.png
https://i.imgur.com/4EoQ7Fi.png

Great analysis! Is there a reason or hypothesis why early-season SSTAs east of FL Panhandle has such strong negative correlation with GoM ACE? Is it as general as "warmer subtropics leads to stability", or is there something that affects the Gulf in particular?

[chaser1]

With regard to "threat analysis" I can fully appreciate, and in fact agree with Josh's perspective regarding his greater interest in high SST'S much closer in. I think some are viewing Josh's perspective a bit out of context. As I see it, the conversation at hand for most of us address what type of season we are all anticipating. When you look at it from the perspective of a homeowner near the coast (or a hurricane chaser), it's very fair to think that their level of concern or interest for what potential RI may occurr during a hurricanes approach address real life impact potential For those folks there is understandably less interest whether the '24 Atlantic Hurricane season reaches a hyperactive state or not, or whether 30 or more named storms managed to all dart northward sharply out to sea.

[cycloneye]

The C3S for August.

 https://twitter.com/catinsight/status/1766819839639687423




 https://twitter.com/Souza101Matt/status/1766825566945017931

[Deshaunrob17]

https://twitter.com/AndyHazelton/status/1766105786445406710

That would probably be the worst case scenario for impacts, indeed: warming of MDR in spring, then strong ridging at the peak of the hurricane season to send storms further west (while being too late to erode the MDR warmth significantly).

I also wonder if the ECMWF animation's fading out of warm anomalies may simply be averages of ensemble members that cancel out the most extreme values (notice the same thing happening to other warm anomalies worldwide, such as east of Japan). But looks like that's a deterministic model so IDK.

Aren’t the anomalies in the tropics naturally supposed to weaken during the warmest time of the year? I always thought so when they are very warm in the winter and spring since there isn’t much room for extra warmth in the traditionally already warm tropics in the summer. They’ve reached their peak. Like the waters could be 2-4 C degrees warmer in the winter , but it’s hard to keep those anomalies in summer/fall.

[USTropics]

The GOM and western Caribbean will support major hurricanes every hurricane season, it's more a matter of when they will warm up vs if. Like Teban stated, the shallow waters in this region make them susceptible to quick transitions of cooling and warming due to local parameters. Since we've been locked into an El Nino pattern for most of winter, with the jet stream positioned further south and numerous low pressure systems developing in the GOM, this has caused cooling. You can see from similar El Nino years that this is a common theme in the GOM and NW Caribbean (and why this has 0 correlation to predicting activity during the hurricane season):
https://i.imgur.com/Z39qQhb.jpeg

Indeed, any correlation between sea surface temperatures in the earliest part of the year in the Western Atlantic or Eastern Pacific with Atlantic seasonal activity is very tenuous. The strongest correlations -- albeit still modest at best -- are over in the equatorial Atlantic. And while we're still quite far out from hurricane season, the strongest correlations between sea surface temperature anomalies and ACE in the Gulf of Mexico are actually not found in the Gulf of Mexico (which fluctuates rapidly as aforementioned), but in the tropical Atlantic. Once storms get going, SSTs and oceanic heat content where storms trek are important factors for storm intensity, but from a seasonal activity perspective, MDR SST anomalies are king as far as SST correlations are concerned, and that's true both at the current long-range and during the hurricane season itself.

Source: Me, using ERSSTv5 for sea surface temperatures and IBTrACS for ACE
https://i.imgur.com/gRIvyeG.png
https://i.imgur.com/4EoQ7Fi.png

Great analysis! Is there a reason or hypothesis why early-season SSTAs east of FL Panhandle has such strong negative correlation with GoM ACE? Is it as general as "warmer subtropics leads to stability", or is there something that affects the Gulf in particular?

Below are 4 composites of years where the GOM/NW Caribbean had negative SSTA in Jan-March (all of these years were active). There is a strong correlation to negative NAO in the months of October-December from the previous years:


Looking at RAPID AMOC values for these years, there's also a correlation of a weaker AMOC (less transport of warm water to the North Atlantic, which is why we see warmth in the MDR but not the western Atlantic/GOM):

[USTropics]

With regard to "threat analysis" I can fully appreciate, and in fact agree with Josh's perspective regarding his greater interest in high SST'S much closer in. I think some are viewing Josh's perspective a bit out of context. As I see it, the conversation at hand for most of us address what type of season we are all anticipating. When you look at it from the perspective of a homeowner near the coast (or a hurricane chaser), it's very fair to think that their level of concern or interest for what potential RI may occurr during a hurricanes approach address real life impact potential For those folks there is understandably less interest whether the '24 Atlantic Hurricane season reaches a hyperactive state or not, or whether 30 or more named storms managed to all dart northward sharply out to sea.

I understand Josh's take, but it wouldn't be prudent to look at SSTA in the GOM for March or April (there's no tropical cyclones in this region). Just look at the change in the CANSIP from Feb to March:

[USTropics]

https://twitter.com/AndyHazelton/status/1766105786445406710

That would probably be the worst case scenario for impacts, indeed: warming of MDR in spring, then strong ridging at the peak of the hurricane season to send storms further west (while being too late to erode the MDR warmth significantly).

I also wonder if the ECMWF animation's fading out of warm anomalies may simply be averages of ensemble members that cancel out the most extreme values (notice the same thing happening to other warm anomalies worldwide, such as east of Japan). But looks like that's a deterministic model so IDK.

Aren’t the anomalies in the tropics naturally supposed to weaken during the warmest time of the year? I always thought so when they are very warm in the winter and spring since there isn’t much room for extra warmth in the traditionally already warm tropics in the summer. They’ve reached their peak. Like the waters could be 2-4 C degrees warmer in the winter , but it’s hard to keep those anomalies in summer/fall.

SSTA is simply a departure from the climatological norm. Sea surface temperatures will naturally continue to warm as we head towards summer solstice in the NH (i.e., the Northern Hemisphere will tilt back towards the sun, which always induces warming of the actual sea surface temperatures). I think of it more as where is the launching point when we enter May? If SSTA is already positively correlated (e.g., they are 1°C above normal before we enter May), this means additional warming will only increase those values. Other factors will determine the rate of warming, such as if we get a burst of trade winds/heavy SAL outbreaks (or vice versa) heading into summer, the difference being the ocean temperatures could be higher before such occurrences.

A simpler way to think of it, if solar radiation adds 2°C of warmth in June no matter what, but we established from May SSTA that the water temperatures were already 1°C above normal, this is additional warmth compared to a year where SSTA was negligible or negative in May.

[cycloneye]

Classic setup. Interesting to see the different ENSO/ATL SST outcomes. The question is whether July/1st half of Aug produces something of quality.

 https://twitter.com/webberweather/status/1766825494077460663

[Steve]

I skimmed through some of Joe B’s Saturday summary. He had a map that he said was the ECMWF hotspots which were in line with weatherbell’s forecast. If you watch it, note the cluster of red off the mouth of the Mississippi and a couple spots just off the Atlantic coast. I’d post the graphic but I don’t think I’d have access to it anyway. But scary for people who live down there and also the MS Gulf Coast.

[cycloneye]

C3S has very positive vorticity for August.

[DorkyMcDorkface]

 https://twitter.com/cyclonicwx/status/1766896734301512029

[Teban54]

The C3S for August.

https://twitter.com/catinsight/status/1766819839639687423

https://twitter.com/Souza101Matt/status/1766825566945017931

The only hope I have (from an impact standpoint) is that some of the models showing warmer SSTAs in the subtropics will play out, and result in less favorable deep tropics. However, even that can be interpreted in the opposite fashion, as indicating stronger ridging and thus MDR storms rolling further west. So I dunno.

[zzzh]

 https://twitter.com/jhomenuk/status/1767272544820686966



The canary current warmth is gradually getting wiped out due to NAO+. And models are trending toward a prolonged NAO+ in the next several weeks so the cooling will continue. The MDR doesn't seem to be affected by this though.

[DorkyMcDorkface]

https://twitter.com/jhomenuk/status/1767272544820686966
The canary current warmth is gradually getting wiped out due to NAO+. And models are trending toward a prolonged NAO+ in the next several weeks so the cooling will continue. The MDR doesn't seem to be affected by this though.

Been noticeable as of late.

[ChrisH-UK]

https://twitter.com/jhomenuk/status/1767272544820686966
The canary current warmth is gradually getting wiped out due to NAO+. And models are trending toward a prolonged NAO+ in the next several weeks so the cooling will continue. The MDR doesn't seem to be affected by this though.

Been noticeable as of late.
https://i.ibb.co/5jv0YZm/crw-ssta-change-natl.png

The reason it looks this way is that the waters around the equator and Africa are already warm with 29-30c temps. The rest of the atlantic is now starting to warm up to it summer levels as the days get longer and more heat is absorbed by the oceans like that red part off the coast of Tampa is 22c.

[Teban54]

 https://twitter.com/catinsight/status/1767331876862050500



 https://twitter.com/catinsight/status/1767333848675688745

[cycloneye]

JB continues with the same hell idea from December.

 https://twitter.com/BigJoeBastardi/status/1767359225678725410

[DorkyMcDorkface]

UKMET ensemble mean in line with the rest of the guidance pretty much.

[DorkyMcDorkface]

https://twitter.com/catinsight/status/1767331876862050500?s=20
https://twitter.com/catinsight/status/1767333848675688745?s=20

 https://twitter.com/webberweather/status/1767503237756674489