2021 EPAC Season

[Yellow Evan]

Shower and thunderstorm activity associated with a weak area of low
pressure located more than 1100 miles southwest of the southern tip
of the Baja California peninsula remains disorganized. This system
is forecast to move generally westward at 5 to 10 mph into a drier
and more stable airmass during the next couple of days with little,
if any, further development expected.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.

[Yellow Evan]

Shower and thunderstorm activity associated with a weak area of low
pressure located about 1200 miles southwest of the southern tip of
the Baja California peninsula is limited. The system is forecast to
move generally westward at 5 to 10 mph into a drier and more stable
airmass during the next couple of days with little, if any, further
development expected.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.

[Kingarabian]

50/50 odds between the EPAC and the GOM for the next system(s) in 10-14 days.

[Yellow Evan]

MJO is forecast to linger in the WPAC for a bit. Favorable conditions close the first week of June as sinking motion will likely dominate thereafter and rather than enter the EPAC MJO is likely to become less defined altogether.

[Kingarabian]

viewtopic.php?f=31&t=121667&p=2904384#p2904384 the averaged out hovmollers show a pretty good VP200 setup in the long range for the EPAC/GOM. Makes sense since we're entering the CAG phase.

[Yellow Evan]

:uarrow:

viewtopic.php?f=31&t=121667&p=2904384#p2904384 the averaged out hovmollers show a pretty good VP200 setup in the long range for the EPAC/GOM. Makes sense since we're entering the CAG phase.

In the first 10 days of June? Yea, though with a -PMM and -PDO, I'd definitely favor development on the Atlantic side, and that pattern shown at the end of the forecast shows the ASW pattern kicking into gear by around June 14 (granted more so ECMWF than GFS).

[Yellow Evan]

This use to be in the first post in threads in the past (and shows the -PDO/-PMM I noted earlier).

[Kingarabian]

How much the Nino regions can warm up will be key in just how active this years hurricane season will be.

2002, 2006, 2009 were examples of seasons that at least initially did not have favorable PDO/PMM setups, but still ended up above average.

[Kingarabian]

00z Euro and CMC have more disturbances in about 8-10 days:



Not including the GFS gyre system which is not yet in range for those models.

[Yellow Evan]

12z ECMWF doesn't have it.

[Kingarabian]

12z Euro keeps the open water system disorganized but the 850mb vort is well and alive. The second disturbance attemps to cross over CA but gets caught up over land.

12z CMC more bullish on future EPAC activity:


GFS not showing the first system and favoring the WCaribb this run for the second system.

[Yellow Evan]

 https://twitter.com/andyhazelton/status/1399479447582031872

[Kingarabian]

https://twitter.com/andyhazelton/status/1399479447582031872?s=21

Lack of anomalous sinking motion from 140E-175E might mean a more active EPAC season than I previously thought.

[Yellow Evan]

https://twitter.com/andyhazelton/status/1399479447582031872?s=21

Lack of anomalous sinking motion from 140E-175E might mean a more active EPAC season than I previously thought.

Pretty clear ASW signal. The kind of setup that favors Atlantic MDR activity for an extended stretch during the peak season and raises the floor of that basin. It’s not the best signal for 2021 but it won’t result in an all time dead season either with La Niña gone and the rather vigorous waves that that pattern would favor.

[Kingarabian]

00z CMC has a couple of systems:

[Yellow Evan]

0z ECMWF has zlich.

[Kingarabian]

12z Euro has the 850mb vort that the CMC is showing. 12z CMC still bullish:

[CyclonicFury]

I wouldn't be surprised to see something develop near the Gulf of Tehauntepec around the Day 8-10 timeframe. With the MJO heading for Phase 8/1, we could see a Central American Gyre develop, and we often see genesis on the eastern Pacific side prior to the Atlantic side, with the EPAC system often contributing to the development of a new system on the Atlantic side. The EPS is split between EPAC and Caribbean/GoM development, but it's always possible we see neither or even both.

[Kingarabian]

00z CMC has development starting in about 7 days:


00z GFS has a development around the 300 hour mark:


The difference in TCG times between the CMC and the GFS means that this future CAG will be around for a while and may spawn multiple systems.

[Kingarabian]

Both the 12z GFS and CMC show two systems, one near 110W in 7 days and another off the coast of Mexico in 10 days.