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

[AlphaToOmega]

Even though the MJO signal per RMM was very weak in 2017, it was at least not in the Atlantic inactive phase for the month of August and most of September. That in itself means the MJO is actually playing a role in enhanced TC activity. This will also be true in about 2 weeks from now. In terms of Climo, the MJO is very weak during the summer months and even through September, compared to late fall and early winter. it takes very little MJO amplitude (which is easier to see on hovmollers than RMM during these months) to trigger TCG.

The current MJO event over the Pacific is actually much stronger than normal considering the time of year, and if it ends up in the Atlantic, we should expect a big uptick in activity similar to what we're currently seeing in the EPAC.

This is why I am very bullish for August. The high amplitude of the MJO was shown in June and July: four tropical storms formed in a 20-day period, and then nothing formed. I expect a very active, impactful August.

[Woofde]

SSTs definitely have warmed up a lot as of recently. The flip side to a calm period is that there are few storms to upwell and use the heat content of the ocean.

It will be interesting to see if this trend continues or if it stops or reverses as we enter a more active period.

Sent from my SM-G988U1 using Tapatalk

[AlphaToOmega]

The CanSIPS still shows a VP anomaly pattern similar to 2010 and 2020. There is no -VP EPac cell.

[aspen]

This phase of EPac activity might give us a hint as to what will happen with the Atlantic starting in a few weeks. While many of these storms are struggling/will struggle due to -ENSO conditions and how close to they are to each other, one thing is clear: the passing MJO has caused a significant spike in TCG in the basin. If the EPac can produce multiple systems like this despite a less favorable base state than the Atlantic, then we could see an activity spike of a similar degree once the MJO has moved basins.

I think it’s possible we could see western development during the early parts of the MJO passage in the August 5-10th range (as tolkram has suggested). Perhaps one of the waves currently in the eastern Atlantic will have lucky timing and arrive in the western part of the basin just as it becomes favorable for genesis and intensification. The CFS hasn’t shown anything like that, but it has proven it cannot catch every single storm, only some of the big ones it seems. Odds are a few slip through the cracks this season too.

[cycloneye]

JB joins the MJO fray.

 https://twitter.com/BigJoeBastardi/status/1421659075553681409

[gatorcane]

A really dry and stable airmass across most of the Atlantic tonight. Here in South Florida, we are experiencing some of this airmass with few clouds and sunny, hot, desert-like conditions. Is very typical for this time of year. Usually by mid August, dry air begins to lose its grip, upper-level winds diminish and the flip switches:

[Shell Mound]

 https://twitter.com/AndyHazelton/status/1421619791761137670



 https://twitter.com/AndyHazelton/status/1421503227573456898



 https://twitter.com/AndyHazelton/status/1421504360908005381



 https://twitter.com/JakeCarstens/status/1421494130706993154



 https://twitter.com/JackSillin/status/1421499426976063489

[Shell Mound]

The current MJO event over the Pacific is actually much stronger than normal considering the time of year, and if it ends up in the Atlantic, we should expect a big uptick in activity similar to what we're currently seeing in the EPAC.

The EPAC systems are actually performing better than one might expect, considering their proximity to one another during -PMM/-PDO/-ENSO. Perhaps this suggests that the background state is more conducive to TCG in the Pacific than the Atlantic in 2021. Until the MJO shifts into the Atlantic systems will struggle due to sinking air and a strong TUTT. I do think we could see some attempts at brief TCG near West Africa during the second week of August, but anything that forms will dissipate rather quickly as it encounters hostile conditions near the islands. Also, the aforementioned TUTT will tend to undercut the WAR and allow avenues for a stronger system to head northward and miss the CONUS.

[AlphaToOmega]

The current MJO event over the Pacific is actually much stronger than normal considering the time of year, and if it ends up in the Atlantic, we should expect a big uptick in activity similar to what we're currently seeing in the EPAC.

The EPAC systems are actually performing better than one might expect, considering their proximity to one another during -PMM/-PDO/-ENSO. Perhaps this suggests that the background state is more conducive to TCG in the Pacific than the Atlantic in 2021. Until the MJO shifts into the Atlantic systems will struggle due to sinking air and a strong TUTT. I do think we could see some attempts at brief TCG near West Africa during the second week of August, but anything that forms will dissipate rather quickly as it encounters hostile conditions near the islands. Also, the aforementioned TUTT will tend to undercut the WAR and allow avenues for a stronger system to head northward and miss the CONUS.

Systems are doing worse than expected in the Pacific. There have been multiple instances in which disturbances were expected to develop (at or above 70% chance of development) in the Pacific but never developed. No such thing has happened in the Atlantic yet.

[MarioProtVI]

The current MJO event over the Pacific is actually much stronger than normal considering the time of year, and if it ends up in the Atlantic, we should expect a big uptick in activity similar to what we're currently seeing in the EPAC.

The EPAC systems are actually performing better than one might expect, considering their proximity to one another during -PMM/-PDO/-ENSO. Perhaps this suggests that the background state is more conducive to TCG in the Pacific than the Atlantic in 2021. Until the MJO shifts into the Atlantic systems will struggle due to sinking air and a strong TUTT. I do think we could see some attempts at brief TCG near West Africa during the second week of August, but anything that forms will dissipate rather quickly as it encounters hostile conditions near the islands. Also, the aforementioned TUTT will tend to undercut the WAR and allow avenues for a stronger system to head northward and miss the CONUS.

Actually the EPac is struggling considering Hilda stopped intensifying and 09E literally fell flat on its head. That shows the EPac is less favorable then thought IMO, and makes me believe Felicia found more of a sweet spot. Also the latest GFS run has a strong TS in the MDR within the next ten days so that point about storms getting sheared near the coast seems moot.

[AlphaToOmega]

What is happening with the CanSIPS? Why is the MDR near-average? Is this a new climatology?

[Shell Mound]

From the Florida weather thread:

Is it just me, or has this been one of the "cooler" SFL summers recently? Obviously it's still hot, but it seems to me that we've seen more breezy and overall cloudy periods than usual.

We haven't seen many of those days with light westerly flow when the temp gets to 95+ in Miami/FLL/WPB before the east coast seabreeze kicks in later PM and all hell breaks loose.

Yes overall this summer has not been one of the hottest summers I can remember. That said the last few weeks have been rather hot but really early morning and late evening haven’t been too bad.

Clearly the Bermuda High has been quite dominant since May and has kept most of the summertime convection inland or along the west coast of the peninsula:



Note that cutoff low along the northwestern Gulf Coast and south-southeasterly flow over most of FL. One can almost envision another Irma- or Elsa-type track:



Overall view of the mid-level (500-mb) regime during the aforementioned timeframe (note the pronounced ridging over and just south of Newfoundland):



A comparison with the H5 pattern during the same timeframe in 2017 shows a similar weakness or cutoff low along the northwestern Gulf Coast:



The major difference is that ridging is farther north thus far in 2021 vs. 2017, so there is more of a chance for impacts farther north along the East Coast.

As an aside, I looked for years that featured TS or stronger tracks similar to Elsa’s that passed within 50 n mi of Steinhatchee, FL, and found the following:



The years were 1853, 1885, 1889, 1902, 1924, 1960, 1996, 2000, and 2013. The above image highlights all MH tracks that occurred in those seasons.



This H5 configuration from late August 1880 looks similar to the H5 pattern since early June 2021 and yielded a strong hurricane impact on eastern FL.

[cycloneye]

 https://twitter.com/GregPostel/status/1421814774279647233

[Shell Mound]

https://twitter.com/GregPostel/status/1421814774279647233

 https://twitter.com/Souza101Matt/status/1421205921401909250



 https://twitter.com/JohnnyParker012/status/1421684637844312068

[AlphaToOmega]

[Category5Kaiju]

The current MJO event over the Pacific is actually much stronger than normal considering the time of year, and if it ends up in the Atlantic, we should expect a big uptick in activity similar to what we're currently seeing in the EPAC.

The EPAC systems are actually performing better than one might expect, considering their proximity to one another during -PMM/-PDO/-ENSO. Perhaps this suggests that the background state is more conducive to TCG in the Pacific than the Atlantic in 2021. Until the MJO shifts into the Atlantic systems will struggle due to sinking air and a strong TUTT. I do think we could see some attempts at brief TCG near West Africa during the second week of August, but anything that forms will dissipate rather quickly as it encounters hostile conditions near the islands. Also, the aforementioned TUTT will tend to undercut the WAR and allow avenues for a stronger system to head northward and miss the CONUS.

From my understanding the depression on Hilda’s left was supposed to become a NS soon, and now it is forecast to remain as remnants of a depression. Hilda to the right was getting sheared by the systems around it many times recently. So I am not very sure if saying that the EPAC have been performing better than expected would be a suitable description; in fact, recent years in the EPAC since 2014 (even -ENSO years) typically would have already had at least 2 majors in the basin by August 1st, and so far we have only seen 1.

[AlphaToOmega]

I believe 1995 is a good analog in terms of steering and landfalls: +NAO, SE Canada ridge, Atlantic Niño, and -ENSO.

[Shell Mound]

The MJO’s being in 8/1/2 while entering a lower amplitude would support a retrogressive “blocking” pattern emerging by mid August, favouring potential impacts.

[Category5Kaiju]

I believe 1995 is a good analog in terms of steering and landfalls: +NAO, SE Canada ridge, Atlantic Niño, and -ENSO.

I personally think a combination between 1996, 1999, 2004, and 2007 would be a good analog too

[aspen]

I believe 1995 is a good analog in terms of steering and landfalls: +NAO, SE Canada ridge, Atlantic Niño, and -ENSO.

Perhaps the possible future Fred could be analogous to 1995’s Hurricane Felix. It formed in the far eastern MDR on August 8th — around the same time Fred has been modeled to develop — and remained weak for most of its time in the MDR before it really got going between 20-25N. Felix’s track is similar to the 06z GFS track (although that’s likely to change). I can see future Fred taking a while to get going while it’s stuck in the MDR, before finding better luck further NW in mid-August, just like Felix.

I’m not saying it’s gonna become a Cat 4 though.