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

[SFLcane]

Based on this graphic Phil Klotzbach posted on Twitter, it appears MDR SSTs have caught up very close to the mean of hyperactive seasons - and are above normal overall. With Elsa forming in the MDR earlier this year and becoming a hurricane, as well as Africa remaining wet, I do not think the MDR will be quite as hostile as some expect it will be.

https://i.imgur.com/4aJ32GP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

We are actually above the hyperactive average in terms of MDR SSTs. Over the last 14 days, the MDR has been consistently above 27 C. I believe the graph is underestimating MDR temperatures.

https://i.postimg.cc/Nf3crBLF/sst-graph-atlmdr.png

You have to plot the anomaly trend. Otherwise it's just climo. Actually cooling still relative to average

[USTropics]

Based on this graphic Phil Klotzbach posted on Twitter, it appears MDR SSTs have caught up very close to the mean of hyperactive seasons - and are above normal overall. With Elsa forming in the MDR earlier this year and becoming a hurricane, as well as Africa remaining wet, I do not think the MDR will be quite as hostile as some expect it will be.

https://i.imgur.com/4aJ32GP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

We are actually above the hyperactive average in terms of MDR SSTs. Over the last 14 days, the MDR has been consistently above 27 C. I believe the graph is underestimating MDR temperatures.

https://i.postimg.cc/Nf3crBLF/sst-graph-atlmdr.png

You have to plot the anomaly trend. Otherwise it's just climo. Actually cooling still relative to average

https://i.postimg.cc/TY6003Q0/F6001-F03-C494-42-B4-943-E-221485-CAFA7-F.jpg

Cooling is concentrated in the eastern MDR currently, here is a trend of the last 7 days:


This in part due to the persistent monsoonal trough that has extended off the coast, here are precipitation anomalies from the past 7 days (quite and active WAM):


We can see a slight rising branch has been established in this region for the past week as well:

[captainbarbossa19]

We are actually above the hyperactive average in terms of MDR SSTs. Over the last 14 days, the MDR has been consistently above 27 C. I believe the graph is underestimating MDR temperatures.

https://i.postimg.cc/Nf3crBLF/sst-graph-atlmdr.png

You have to plot the anomaly trend. Otherwise it's just climo. Actually cooling still relative to average

https://i.postimg.cc/TY6003Q0/F6001-F03-C494-42-B4-943-E-221485-CAFA7-F.jpg

Cooling is concentrated in the eastern MDR currently, here is a trend of the last 7 days:
https://i.imgur.com/1Mx2mVQ.png

This in part due to the persistent monsoonal trough that has extended off the coast, here are precipitation anomalies from the past 7 days (quite and active WAM):
https://i.imgur.com/rx38jNY.png

We can see a slight rising branch has been established in this region for the past week as well:
https://i.imgur.com/M9Nu5N8.png

Looks like the Gulf and Bahamas region are still warming too.

[Shell Mound]

This keeps showing up…

https://i.postimg.cc/W4jLpZSd/0-BD164-F4-7455-4983-8425-9-F7-C9-A411891.jpg

...except nothing is likely to be out there before the last few days of August. August 18 is still too early. By early September that ridge is likely to be gone. According to the CFSv2’s weeklies, ridging over southeastern Canada is likely to be strongest during 18–25 August, so if a TC were present near the islands during that timeframe, it would be in a prime position to affect the CONUS. Afterward, however, the CFSv2 shows ridging gradually shifting northward and leaving a trough underneath in time for the peak of the season. So maybe the CONUS will escape serious impacts this season, given that most Category-4+ landfalls tend to be associated with storms that develop in the MDR.



 https://twitter.com/AndyHazelton/status/1422658917344108554

[weeniepatrol]

I know shear maps are extremely transient, but honestly, if this is how insignificant the TUTT is before the MJO is even close to being in a favorable position for the Atlantic and we have weeks and weeks of gradually improving conditions consistent with climatology then i'm terrified for later this month.

Low shear and deep-layered easterlies already dominate from Africa to the Caribbean Sea..

[AlphaToOmega]

There are three disturbances in the Atlantic as of now.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM CCA

Tropical Weather Outlook...Corrected
NWS National Hurricane Center Miami FL
800 AM EDT Wed Aug 4 2021

Corrected order of disturbances

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A small and weak area of low pressure, with limited shower and
thunderstorm activity, is passing near the Cabo Verde Islands.
Significant development of this system is not expected during the
next day or so due to unfavorable environmental conditions.
Thereafter, this system is forecast to move northward or
north-northwestward over cooler waters, ending its development
chances. Locally heavy rainfall and gusty winds are possible over
portions of the Cabo Verde Islands through today.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...near 0 percent.

2. A tropical wave located over the central tropical Atlantic is
producing a broad area of disorganized showers and thunderstorms.
Environmental conditions are expected to be marginally conducive
for some slow development east of the Lesser Antilles by Sunday and
into early next week while the disturbance moves west-northwestward
at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

3. A tropical wave is forecast to move off the west coast of Africa by
late Thursday. Environmental conditions appear somewhat conducive
for some slow development over the far eastern Atlantic through the
weekend into early next week while the system moves generally
westward at about 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.
Forecaster Stewart

If these numbers are to be trusted, the chance of Disturbance II developing is 20%; the chance of Disturbance III developing is 30%. Therefore, the chance of Disturbance II not developing is 80%; Disturbance III, 70%. Therefore, the chance of neither disturbance developing is 0.8 * 0.7 = 56%. There is a 42% chance of a disturbance developing within 5 days.

[Category5Kaiju]

I know shear maps are extremely transient, but honestly, if this is how insignificant the TUTT is before the MJO is even close to being in a favorable position for the Atlantic and we have weeks and weeks of gradually improving conditions consistent with climatology then i'm terrified for later this month.

Low shear and deep-layered easterlies already dominate from Africa to the Caribbean Sea..

https://i.imgur.com/HebEnbA.gif

Hmm, well I guess the ECAR may not be as much as a graveyard as it has been in previous years we’ll see though.

[AutoPenalti]

There are three disturbances in the Atlantic as of now.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM CCA

Tropical Weather Outlook...Corrected
NWS National Hurricane Center Miami FL
800 AM EDT Wed Aug 4 2021

Corrected order of disturbances

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A small and weak area of low pressure, with limited shower and
thunderstorm activity, is passing near the Cabo Verde Islands.
Significant development of this system is not expected during the
next day or so due to unfavorable environmental conditions.
Thereafter, this system is forecast to move northward or
north-northwestward over cooler waters, ending its development
chances. Locally heavy rainfall and gusty winds are possible over
portions of the Cabo Verde Islands through today.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...near 0 percent.

2. A tropical wave located over the central tropical Atlantic is
producing a broad area of disorganized showers and thunderstorms.
Environmental conditions are expected to be marginally conducive
for some slow development east of the Lesser Antilles by Sunday and
into early next week while the disturbance moves west-northwestward
at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

3. A tropical wave is forecast to move off the west coast of Africa by
late Thursday. Environmental conditions appear somewhat conducive
for some slow development over the far eastern Atlantic through the
weekend into early next week while the system moves generally
westward at about 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.
Forecaster Stewart

If these numbers are to be trusted, the chance of Disturbance II developing is 20%; the chance of Disturbance III developing is 30%. Therefore, the chance of Disturbance II not developing is 80%; Disturbance III, 70%. Therefore, the chance of neither disturbance developing is 0.8 * 0.7 = 56%. There is a 42% chance of a disturbance developing within 5 days.

4 days into August and we are at 3 disturbances.

[SFLcane]

[aspen]

The Atlantic is finally starting to wake up…

With so many active waves and many more to come, we really need to watch out for anything that makes it into the Gulf. The entire region is at least 30C, with half of the Gulf having 31-32C SSTs, along with the broiling Loop Current. It’s a powder keg waiting to be lit. I don’t know how much the EPac -VP cell will suppress activity there, however.

[SconnieCane]

This keeps showing up…

https://i.postimg.cc/W4jLpZSd/0-BD164-F4-7455-4983-8425-9-F7-C9-A411891.jpg

...except nothing is likely to be out there before the last few days of August. August 18 is still too early. By early September that ridge is likely to be gone. According to the CFSv2’s weeklies, ridging over southeastern Canada is likely to be strongest during 18–25 August, so if a TC were present near the islands during that timeframe, it would be in a prime position to affect the CONUS. Afterward, however, the CFSv2 shows ridging gradually shifting northward and leaving a trough underneath in time for the peak of the season. So maybe the CONUS will escape serious impacts this season, given that most Category-4+ landfalls tend to be associated with storms that develop in the MDR.

https://i.ibb.co/xf29FNH/Weekly-1.png

https://twitter.com/AndyHazelton/status/1422658917344108554

I think you're putting way too much stock in the CFS at a month out.

[Category5Kaiju]

The Atlantic is finally starting to wake up…

With so many active waves and many more to come, we really need to watch out for anything that makes it into the Gulf. The entire region is at least 30C, with half of the Gulf having 31-32C SSTs, along with the broiling Loop Current. It’s a powder keg waiting to be lit. I don’t know how much the EPac -VP cell will suppress activity there, however.

For real, let's hope we don't get any storm that is able to take full advantage of those conditions and blow up into a monster stronger than the most powerful Gulf storm recorded, Rita. If in recent years RI Gulf storms have been the norm, then I can only imagine what those really warm waters and highly pronounced Loop Current would be capable of supporting; it ain't pretty one bit.

[AlphaToOmega]

The Atlantic is finally starting to wake up…

With so many active waves and many more to come, we really need to watch out for anything that makes it into the Gulf. The entire region is at least 30C, with half of the Gulf having 31-32C SSTs, along with the broiling Loop Current. It’s a powder keg waiting to be lit. I don’t know how much the EPac -VP cell will suppress activity there, however.

An EPAC -VP cell will not hinder West Atlantic tropical activity. Remember 2005: there was an EPac -VP cell; yet there was Dennis, Emily, Katrina, Rita, Wilma, and Beta, all powerful Western Atlantic hurricanes. The warm Gulf of Mexico will likely be enough to support a major hurricane.

[psyclone]

The Atlantic is finally starting to wake up…

With so many active waves and many more to come, we really need to watch out for anything that makes it into the Gulf. The entire region is at least 30C, with half of the Gulf having 31-32C SSTs, along with the broiling Loop Current. It’s a powder keg waiting to be lit. I don’t know how much the EPac -VP cell will suppress activity there, however.

Speaking on a hyperlocal basis...the shelf waters over much of the gulf are at very warm levels that would permit a storm to strengthen right up until landfall. We've had quite a bit of onshore flow here lately and it has been just obnoxious at night as that marine layer advects landward. temps in the mid 80's at night with upper 70's dewpoints have been common...true "head in the dishwasher" conditions. If a storm is able to take advantage of that...it's going to be problematic.

[Category5Kaiju]

If you looks closely at the Gulf, you can definitely see patches of water near the dreaded 32 C mark (especially off of Key West and the South Florida tip). Nice to swim in, until you realize that that is just sitting rocket fuel for any hurricanes that go over it.

[aspen]

What’s up with that persistent stream of -SST anomalies coming from the ABC islands? It’s been there for weeks, and in SST maps from 2020 that have been posted, it is either very weak or non-existent.

[Shell Mound]

...we really need to watch out for anything that makes it into the Gulf. The entire region is at least... It’s a powder keg waiting to be lit.

For real, let's hope we don't get any storm that is able to take full advantage of those conditions and blow up into a monster

Regarding the Gulf: we say the same thing every year. It’s a broken record. The Gulf is always sufficiently warm to support Category-5 cyclones, even during -AMO cycles. “Record-high” SST and/or THC in the Gulf are irrelevant, whereas shear and dry air are relevant. Anyway, vertical wind shear was above average in the Caribbean during July 2021, which would actually correlate with lower seasonal ACE. Combined with the -VP over the EPAC, this could indicate more hostile conditions over the Gulf, Caribbean, and western MDR during the peak period of ASO.

[AlphaToOmega]

What’s up with that persistent stream of -SST anomalies coming from the ABC islands? It’s been there for weeks, and in SST maps from 2020 that have been posted, it is either very weak or non-existent.

[AlphaToOmega]

...we really need to watch out for anything that makes it into the Gulf. The entire region is at least... It’s a powder keg waiting to be lit.

For real, let's hope we don't get any storm that is able to take full advantage of those conditions and blow up into a monster

Regarding the Gulf: we say the same thing every year. It’s a broken record. The Gulf is always sufficiently warm to support Category-5 cyclones, even during -AMO cycles. “Record-high” SST and/or THC in the Gulf are irrelevant, whereas shear and dry air are relevant. Anyway, vertical wind shear was above average in the Caribbean during July 2021, which would actually correlate with lower seasonal ACE. Combined with the -VP over the EPAC, this could indicate more hostile conditions over the Gulf, Caribbean, and western MDR during the peak period of ASO.

A -VP cell in the EPac is irrelevant. 2005 had a -VP cell in the EPAC; yet Hurricanes Dennis, Emily, Katrina, Rita, Wilma, and Beta formed, all of which were Western Atlantic major hurricanes.

[AlphaToOmega]

Notice the below-average wind shear in the Caribbean Sea and the Gulf of Mexico

It is nothing but wishful thinking to assume the Caribbean Sea and/or the Gulf of Mexico will be hostile for tropical development.