2021 EPAC Season

[gatorcane]

EPAC back to be active on the long-range GFS = slower Atlantic:

[Yellow Evan]

18z GFS doing what it does best.

[Kingarabian]

https://i.imgur.com/KFnODhb.png

18z GFS doing what it does best.

Shows 20kts of shear over it too lol

[Yellow Evan]

May explain this but it’s also not that different from the ECMWF.

[AlphaToOmega]

The Atlantic is likely to be very convectively active in the next few weeks, and the East Pacific is already looking convectively quiet aside from Tropical Depression Kevin and Tropical Storm Linda. In the East Pacific, tropical cyclone formation is not expected during the next five days, and neither the GFS nor the ECMWF nor the CanSIPS show any tropical cyclone formation within the next 240 hours. Combined with an MJO phase that is expected to be unfavorable for East Pacific tropical cyclone development, the East Pacific is likely to be quiet for a while.

[Kingarabian]

12z GFS and CMC look pretty quiet after Linda.

12z Euro wants the sloppy storm party to continue:

[Yellow Evan]

 https://twitter.com/andyhazelton/status/1425927832790835212

[Category5Kaiju]

12z GFS and CMC look pretty quiet after Linda.

12z Euro wants the sloppy storm party to continue:
https://i.imgur.com/aaTrY8l.gif

The Euro still doesn't get it, I see.

[Kingarabian]

Time frame is coming in from the CMC and Euro in regards to another TC. Most likely it will be weaker if it tries to form near Mexico.

[Yellow Evan]

0z GFS spins up 3 weak systems the next 16 days.

[Kingarabian]

Looks like another active EPAC monsoon trough is setting up in the next 3-4 days. Models agree that there will be some sort of development(s) from it. But don't agree on that exact location.

Will need a bit more continuity for a NHC circle, but members from the EPS/GEPS/GEFS and now the 18z GFS showing development inside 5 days near 115W.


Good agreement for another separate system in 7-10 days between 100W/120W.



Of course any modeled strong system near Mexico is probably fake news.

[Yellow Evan]

This is a much more favorable SST configuration. Legit +PDO horseshoe and the warm SST's near Japan seem to have faded markedly.

[Yellow Evan]

0z GFS has 3 systems by day 10 although all slop and dropped the short term one from 18z.

[Kingarabian]

https://i.imgur.com/7O5MxZt.png

This is a much more favorable SST configuration. Legit +PDO horseshoe and the warm SST's near Japan seem to have faded markedly.

I don't see the +PDO yet. Maybe some hints closer to Japan but certainly not near or SW of the WCONUS. It's more of a neutral PDO look now.

But the entire picture is starting to look like a 1990 esque rebound though the re-warming is happening different areas.

[Kingarabian]

00z GFS:

[Yellow Evan]

https://i.imgur.com/7O5MxZt.png

This is a much more favorable SST configuration. Legit +PDO horseshoe and the warm SST's near Japan seem to have faded markedly.

I don't see the +PDO yet. Maybe some hints closer to Japan but certainly not near or SW of the WCONUS. It's more of a neutral PDO look now.

But the entire picture is starting to look like a 1990 esque rebound though the re-warming is happening different areas.

https://i.imgur.com/1mPJ2EZ.gif

Yeah it's not full on positive PDO because there's still some pockets of warm water but from the prospective of increased activity of the season, having a +PDO horsheshoe with warm waters off Baja and Gulf of Alaska is a positive development.

[Yellow Evan]

https://www.data.jma.go.jp/gmd/kaiyou/d ... do/pdo.txt

2021-03 -0.8914
2021-04 -0.8143
2021-05 -1.0403
2021-06 -1.0005
2021-07 -1.2792

PDO value probably skewed from the epic July Sea of Japan warming that seems to have faded. August will be interesting.

https://www.aos.wisc.edu/~dvimont/MMode ... me/PMM.txt

2021 1 -1.09 -17.07
2021 2 -2.64 -7.06
2021 3 -3.69 -7.08
2021 4 -1.22 4.65
2021 5 -2.11 -1.40
2021 6 -2.60 2.55
2021 7 -1.38 -1.88

A small improvement in the -PMM department.

Also keep in mind we've had westerlies across the tropics at least for much of early August. It won't exactly last.

[Yellow Evan]

Interestingly, July SSTs in the basin took a turn for the worse. Coldest since 2012 and comparable to May 2015.

2009 23.173 23.256 23.566 24.160 24.759 25.558 26.102 26.735 26.758 26.406 24.951 24.001
2010 23.125 22.875 23.101 23.958 24.666 24.938 25.163 25.690 25.606 24.951 23.976 22.707
2011 22.118 22.064 22.848 23.761 24.471 24.667 24.993 25.656 25.930 25.294 24.273 23.083
2012 22.622 22.687 23.008 23.792 24.602 24.710 25.182 25.781 26.117 25.972 24.981 24.202
2013 22.968 23.083 23.136 24.002 24.960 25.198 25.775 26.308 26.096 25.695 24.727 23.730
2014 22.960 23.397 23.989 24.531 25.226 25.828 26.403 26.953 26.477 26.362 25.208 24.403
2015 23.775 23.811 24.167 25.251 25.677 25.988 26.726 27.321 27.385 27.247 26.263 24.934
2016 23.804 23.654 24.204 24.767 25.385 25.761 26.339 26.773 26.648 26.366 25.780 24.365
2017 23.677 23.522 24.058 24.522 25.060 25.245 26.008 26.641 26.422 26.074 25.657 24.603
2018 23.660 23.841 24.104 24.779 25.373 25.581 26.242 26.740 26.790 26.073 25.073 24.103
2019 23.587 23.760 24.137 24.574 25.167 25.452 25.886 26.813 26.682 26.033 25.209 24.412
2020 23.530 23.292 23.990 24.462 25.173 25.527 26.050 26.501 26.350 26.291 25.437 23.864
2021 22.930 22.842 23.173 24.042 24.674 25.153 25.570 -999.999 -999.999 -999.999 -999.999 -999.999
-999.999

[gatorcane]

The GFS has the wave train cranking up again in the EPAC:

[Kingarabian]

Operational Euro backing off on additional EPAC development for the next 10 days. But the EPS still bullish. So is the CMC and UKMET.

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 114 HOURS
FORECAST POSITION AT T+114 : 18.7N 106.1W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 22.08.2021 120 18.7N 107.5W 996 38
0000UTC 23.08.2021 132 18.6N 110.0W 996 37
1200UTC 23.08.2021 144 18.8N 112.8W 997 34

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 132 HOURS
FORECAST POSITION AT T+132 : 12.8N 98.6W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 23.08.2021 132 12.8N 98.6W 1003 30
1200UTC 23.08.2021 144 13.7N 101.5W 1001 35