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

[CyclonicFury]

The MDR (east Caribbean to Africa south of 18N) isn't looking like it will have a very favorable environment again this year. Storms may struggle until they reach the western Caribbean, as they did last year.

Why do you think so?

[ClarCari]

Those maps suggest more low-riders that rake the upper Antilles ala Georges, Irma, and Maria and move on to the East Gulf or East Coast (or maybe south Florida for once ).
I don’t expect the same amount of WCAR storms we saw like last year or Ivan like Caribbean tours but we’ll see.
2005 had Caribbean activity only at the beginning with Dennis and Emily and at the end with Wilma and Beta, but it was dead in the rest of ASO that year.

[SFLcane]

The MDR (east Caribbean to Africa south of 18N) isn't looking like it will have a very favorable environment again this year. Storms may struggle until they reach the western Caribbean, as they did last year.

Why do you think so?

And that is the worst possible news as the later these waves take to develop the greater odds they have of impacting land.

[aspen]

Do Y'all have a bad feeling about a 2013 Sneak attack? I do have that feeling . . .

Another 2013, as said many times, is highly unlikely. 2013 was abnormal due to a collapse of the Thermohaline Cycle, which led to spring-like atmospheric conditions persisting and ruining the apparently good conditions forecast prior to the Spring Predictability Barrier. For another 2013, we would need to see the THC collapse again, and since we’ve already gone through 2013, we know the warning signs of such an anomalous event occurring.

A 2006 reversal is much more likely than another 2013. While a switch from this strong La Niña (technically now cool-neutral with La Niña atmo) to a full-blown El Niño by ASO is not very likely, it’s still a possibility, and those warm subsurface anomalies bear watching.

[TROPICALCYCLONEALERT]

I guess this can go here, though I admit it’s more or less a curiosity at the moment. With the succession of two large troughs off the East Coast (one of which is bringing cold weather to the region now), we’ve entered a period of -NAO as convection spurred on by strong upper level divergence/diffluence causes air to warm and expand downstream, forcing the development of a ridge. This wavebreaking allows for the development of cut off lows, completing the -NAO footprint. With regards to impact on trade winds in the MDR, placement is key. This particular event appears to be too far north to allow for anomalous westerlies to dominate the tropical Atlantic. Quite interesting nonetheless.

[DorkyMcDorkface]

Currently appears that we have almost a pseudo -AMO look in the Atlantic at the moment with the warm subtropics but slightly cooler than average MDR and Northern Atlantic. However, with that being said something that sticks out to me is the current look of the Canary Current. Note that is is decently warm relative to average at the present time. This is generally unorthodox for a configuration like this.


Historically in the month of April SSTs positive SSTs in this region do correlate with higher seasonal Atlantic activity.


Something else to consider; despite the less-than-optimal configuration at the moment, it looks like we may be in for another strong West African Monsoon (WAM) this year with the Sahel being quite moist in terms of rainfall. Outside of the fact that this could mean a beefier wave train of course, a stronger WAM can also help induce more westerlies in the MDR and thus weaken trade winds, which can thus serve to warm the waters down there. This is something we've seen over the past few years during this streak of active hurricane seasons and it is certainly something to watch for again this year.

[NotSparta]

Do Y'all have a bad feeling about a 2013 Sneak attack? I do have that feeling . . .

Another year, another 2013 post... Never fails
(No offense btw, I just find it amusing)

It's only April too, usually we have to wait until July or August for the 2013 posts

[SFLcane]

Interesting video here he adds a few reasons as to why Florida should watch closely this upcoming season with ridge position.

https://youtu.be/o-ZSC9siKUU

[Category5Kaiju]

I just remember how people were saying "oh look another 2013 about to happen" especially in 2017 and 2020, and of course look how that turned out. As much as I would love for another 2013 to happen again after all the brutal storms from the past 5 years, so far it looks like 2013 and 2021 don't really have much in common in terms of sst anomalies and atmosphere-wise.

[Shell Mound]

With the African monsoon being hyperactive once again, waves are likely to be highly amplified, the ITCZ displaced farther to the north, and systems much slower to develop over the MDR relative to normal. Along with a transition toward neutral or warm neutral ENSO, this means that the MDR is becoming less favourable than originally expected, given that the AMO is lukewarm at best rather than strongly positive at the moment. Additionally, the various models suggest steering may favour OTS tracks that avoid the Caribbean, GoM, and most of the U.S. East Coast (excluding New England). The lack of a busy MDR alone tends to the decrease the risk of major hurricanes striking the CONUS, since climatologically three-fourths of all MH to strike the CONUS since 1851 developed first over the MDR. I think 2006 might be a decent analog in terms of tracks, if not numbers.

[Category5Kaiju]

With the African monsoon being hyperactive once again, waves are likely to be highly amplified, the ITCZ displaced farther to the north, and systems much slower to develop over the MDR relative to normal. Along with a transition toward neutral or warm neutral ENSO, this means that the MDR is becoming less favourable than originally expected, given that the AMO is lukewarm at best rather than strongly positive at the moment. Additionally, the various models suggest steering may favour OTS tracks that avoid the Caribbean, GoM, and most of the U.S. East Coast (excluding New England). The lack of a busy MDR alone tends to the decrease the risk of major hurricanes striking the CONUS, since climatologically three-fourths of all MH to strike the CONUS since 1851 developed first over the MDR. I think 2006 might be a decent analog in terms of tracks, if not numbers.

Just curious but is there a specific reason why you think 2006 is a good analog year for tracks? Years like 2001 or 2012 were what came to my mind as well

Also a busy MDR alone does not actually mean less major US hurricane strikes; Wilma, Dennis, Katrina, Opal, Rita, Charley are some examples of this.

[toad strangler]

Do Y'all have a bad feeling about a 2013 Sneak attack? I do have that feeling . . .

Another year, another 2013 post... Never fails
(No offense btw, I just find it amusing)

It's only April too, usually we have to wait until July or August for the 2013 posts

Yes, but first we have to get through a long spell of SAL hand wringing.

[NDG]

I remember clearly that what killed the 2006 season's active forecast in the Atlantic was a weak El Nino developed unforecasted by many, along with a fairly active far eastern EPAC it was enough for shear to take over the GOM and Caribbean. I remember Ernesto hitting a brick wall of shear especially in the mid levels south of Hispaniola. PDO was also not as cool as it is now.

[Shell Mound]

With the African monsoon being hyperactive once again, waves are likely to be highly amplified, the ITCZ displaced farther to the north, and systems much slower to develop over the MDR relative to normal. Along with a transition toward neutral or warm neutral ENSO, this means that the MDR is becoming less favourable than originally expected, given that the AMO is lukewarm at best rather than strongly positive at the moment. Additionally, the various models suggest steering may favour OTS tracks that avoid the Caribbean, GoM, and most of the U.S. East Coast (excluding New England). The lack of a busy MDR alone tends to the decrease the risk of major hurricanes striking the CONUS, since climatologically three-fourths of all MH to strike the CONUS since 1851 developed first over the MDR. I think 2006 might be a decent analog in terms of tracks, if not numbers.

Just curious but is there a specific reason why you think 2006 is a good analog year for tracks? Years like 2001 or 2012 were what came to my mind as well

Also a busy MDR alone does not actually mean less major US hurricane strikes; Wilma, Dennis, Katrina, Opal, Rita, Charley are some examples of this.

Vice versa. I pointed out that an inactive MDR tends to mean fewer MH impacts on the CONUS, based on climatology, given that approximately three-fourths of all historical MH to strike the CONUS developed at first in the MDR. As far as analogs are concerned, I chose 2006 because ENSO will likely be warming through the peak of the season, and we are transitioning out of moderate Niña conditions to neutral or even warm neutral ENSO, unlike 2001 or 2012. Additionally, in line with NDG’s observation, most of the recent guidance suggests above-average precipitation over the easternmost tropical Pacific either during or around ASO, suggesting that shear may be above average over the Caribbean basin during the peak of the season, owing to outflow from convection induced by warming SSTs over the NINO zones. Warming ENSO also tends to result in more sinking air over the MDR, a somewhat stronger TUTT, and higher MSLP, meaning more hostile conditions over the MDR as well as the Caribbean. The more persistent TUTT may also pull storms that do form northward and/or OTS.

[GrayLancer18]

 https://twitter.com/webberweather/status/1378716276357353472

[Category5Kaiju]

https://twitter.com/webberweather/status/1378716276357353472

Hang on, is this model run assuming that an El Nino will form? Because unless I am mistaken, I cannot think of how a neutral or La Nina would make the Atlantic that dry?

[toad strangler]

https://twitter.com/webberweather/status/1378716276357353472

The trend on that canSIPS progression is welcoming but don't misread the map. Those are anomalies and don't mean bone dry. The yellow shading isn't much below normal.

[aspen]

I’m seriously starting to get vibes that 2021 will end the steak of above-average seasons, due to the less and less conductive moisture model runs and, most importantly, the growing possibility that a La Niña will not be present by ASO. A full-blown El Niño, while still not super likely, has become more probable than back in January.

[Category5Kaiju]

All I can say is at this point I am going to wait until summer because I remember hearing people look at some of the early models and believe 2017, 2018, and 2019 would be below average and not bad seasons, and look how that turned out. Not trying to point out anybody in particular, but I'm just saying based on what we've seen in recent years I am going to assume that 2021 will be a busy and active season just as a precaution unless I know for sure the signs point otherwise.

[AnnularCane]

Do Y'all have a bad feeling about a 2013 Sneak attack? I do have that feeling . . .

Another 2013, as said many times, is highly unlikely. 2013 was abnormal due to a collapse of the Thermohaline Cycle, which led to spring-like atmospheric conditions persisting and ruining the apparently good conditions forecast prior to the Spring Predictability Barrier. For another 2013, we would need to see the THC collapse again, and since we’ve already gone through 2013, we know the warning signs of such an anomalous event occurring.

By the way, what are the signs of a thermohaline collapse?