2023 EPAC Season

[cycloneye]

GFS develops a powerful hurricane from the second AOI.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Fri Jun 23 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Off the Southwestern Coast of Mexico:
A broad trough of low pressure located several hundred miles south
of southern Mexico continues to produce a large area of disorganized
showers and thunderstorms. Environmental conditions appear conducive
for development of this system, and a tropical depression is
expected to form during the next several days while it moves
generally west-northwestward and parallel to the southwestern coast
of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...90 percent.

South of Southern Mexico:
An area of low pressure could form during the early to middle part
of next week several hundred miles south of El Salvador, Guatemala,
and southern Mexico. Some gradual development of this system is
possible thereafter as it moves slowly west-northwestward, remaining
offshore of the southern coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Reinhart

[cycloneye]

The second AOI develops from the remanants of Bret as it crosses CA acording to GFS. (Red line)

[Yellow Evan]

it does not. Forms from AEW currently over Panama and aided by a far eastern Pacific WWB.

[Kingarabian]

:uarrow: it does not. Forms from AEW currently over Panama and aided by a far eastern Pacific WWB.

The remnants of Bret will play a big role. Can clearly see it cross and combine on most of the GFS runs.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Jun 24 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Off the Southwestern Coast of Mexico:
A broad trough of low pressure located several hundred miles south
of the southwestern coast of Mexico continues to produce a large
area of disorganized showers and thunderstorms. Environmental
conditions appear conducive for development of this system, and a
tropical depression is expected to form during the early to middle
part of next week while it moves generally west-northwestward,
parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...90 percent.

2. South of Southern Mexico:
An area of low pressure could form early next week several hundred
miles south of El Salvador, Guatemala, and southern Mexico. Some
gradual development of this system is possible thereafter as it
moves slowly west-northwestward, remaining offshore of the southern
coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

Forecaster Papin/Cangialosi

[aspen]

Looks like the first AOI will be a sprawling, unfocused system. I doubt it gets much stronger than a Cat 1. The GFS is of course aggressive with the second AOI and shows it as a more compact system, but these very strong systems close to Central America are often overhyped by the GFS, so I’ll believe it when I see it.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sat Jun 24 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Off the Southwestern Coast of Mexico:
An elongated trough of low pressure located several hundred miles
south of the southwestern coast of Mexico continues to produce a
large area of disorganized showers and thunderstorms. Environmental
conditions appear conducive for development of this system, and a
tropical depression is expected to form during the early to middle
part of next week while it moves generally west-northwestward,
parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...90 percent.

2. South of Southern Mexico:
An area of low pressure could form early next week several hundred
miles south of El Salvador, Guatemala, and southern Mexico. Some
gradual development of this system is possible thereafter as it
moves slowly west-northwestward, remaining offshore of the southern
coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

Forecaster Papin

[cycloneye]

Second A0I up to 40% in 7 days.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sat Jun 24 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Off the Southwestern Coast of Mexico:
An elongated trough of low pressure located several hundred miles
south of the southwestern coast of Mexico continues to produce a
broad area of disorganized showers and thunderstorms. Environmental
conditions appear conducive for development of this system, and a
tropical depression is expected to form during the early to middle
part of next week as it moves generally west-northwestward, parallel
to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...90 percent.

South of Southern Mexico:
An area of low pressure is forecast to form early next week several
hundred miles south of El Salvador, Guatemala, and southern Mexico.
Some gradual development of this system is possible thereafter, and
a tropical depression could form during the middle to latter part
of next week while it moves slowly west-northwestward, remaining
offshore of the southern and southwestern coasts of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.

$$
Forecaster Reinhart

[Yellow Evan]

First AOI is quite broad as it because the convective nature of the monsoon trough makes it difficult for a compact wrap up to occur. I doubt it has time to become more than a tropical storm or weak hurricane.

Second AOI will have shear due to westerly low level flow and has less model support but will likely have more time over warm SSTs.

[Kingarabian]

06z GFS back with developing both systems. 00z GFS and 00z Euro barely showed development, weak development of the first AOI only.

[cycloneye]

Backtracking a little on AOI #1.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sun Jun 25 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Off the Southwestern Coast of Mexico:
An elongated trough of low pressure located several hundred miles
south of the southwestern coast of Mexico continues to produce a
large area of disorganized showers and thunderstorms. This
disturbance has not become any better organized over the past day or
so, but environmental conditions still appear generally favorable
for gradual development of this broad system. A tropical depression
is likely to form during the middle part of this week as the system
moves generally west-northwestward, parallel to the southwestern
coast of Mexico.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...80 percent.

South of Southern Mexico:
An area of low pressure is forecast to form early next week several
hundred miles south of El Salvador, Guatemala, and southern Mexico.
Some gradual development of this system is possible thereafter, and
a tropical depression could form during the middle to latter part
of this week while it moves slowly west-northwestward, remaining
offshore of the southern and southwestern coasts of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Papin/Pasch

[cycloneye]

Good discussion in this twitter thread about what is going on with the lack of activity so far. Read the replies.

 https://twitter.com/dmorris9661/status/1672933952175185921

[cycloneye]

Nothing new with no change in the percents.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sun Jun 25 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Off the Southwestern Coast of Mexico:
An elongated trough of low pressure located several hundred miles
south of the southwestern coast of Mexico continues to produce a
large area of showers and thunderstorms. This activity remains
disorganized, but environmental conditions still appear generally
favorable for gradual development of this broad system. A tropical
depression is likely to form during the middle part of this week as
the system moves generally west-northwestward, parallel to the
southwestern coast of Mexico.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...80 percent.

South of Southern Mexico:
An area of low pressure is expected to form over the next day or so
several hundred miles south of El Salvador, Guatemala, and southern
Mexico. Some gradual development of this system is possible
thereafter, and a tropical depression could form during the middle
to latter part of this week while it moves slowly
west-northwestward, remaining offshore of the southern and
southwestern coasts of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Papin

[cycloneye]

Some change on the language on both systems. more concentrated area on AOI #1 and low is forming south of Costa Rica for AOI #2.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sun Jun 25 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Off the Southern and Southwestern Coast of Mexico:
A more concentrated area of disturbed weather has formed a few
hundred miles southwest of Acapulco, Mexico at the eastern end of an
elongated trough of low pressure. Environmental conditions appear
generally favorable for gradual development of this system, and a
tropical depression is likely to form during the middle part of this
week as the system moves generally west-northwestward, parallel to
the southwestern coast of Mexico.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...80 percent.

2. South of Southern Mexico and Central America:
A low pressure area is forming a few hundred miles southwest of the
coast of Costa Rica. Some gradual development of this system is
possible during the next several days, and a tropical depression
could form during the middle to latter part of this week while it
moves slowly west-northwestward, remaining offshore of the southern
and southwestern coasts of Mexico.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...60 percent.

Forecaster Beven

[Kingarabian]

These should be developing considering their placement and whats going on in the far eastern Pacific, ENSO wise.

But there's still some La Nina atmosphere left north east Pacific with higher than normal pressure still in control. That typically means systems off of Mexico will struggle if they track more NW/NNW vs WNW.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Jun 26 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Off the Southern and Southwestern Coast of Mexico:
An elongated trough of low pressure located several hundred miles
south of the southwestern coast of Mexico continues to produce a
large area of disorganized showers and thunderstorms. Environmental
conditions appear generally favorable for gradual development of
this system, and a tropical depression is likely to form during the
middle part of this week as the system moves generally
west-northwestward, parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...80 percent.

2. South of Southern Mexico and Central America:
A broad area of low pressure area is located a few hundred miles
southwest of the coast of Costa Rica. Some gradual development of
this system is possible during the next several days, and a tropical
depression could form during the middle to latter part of this week
while it moves slowly west-northwestward, remaining offshore of the
southern and southwestern coasts of Mexico.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...60 percent.

Forecaster Papin/Pasch

[cycloneye]

The first one SW of Acapulco gets the invest 91E designation.

Invest 91E

[cycloneye]

The second AOI up to 20%/70%.

South of Southern Mexico and Central America:
A broad area of low pressure located a few hundred miles south of
the coasts of Guatemala and El Salvador is associated with an area
of disorganized showers and thunderstorms. Some gradual development
of this system is possible during the next several days, and a
tropical depression is likely to form during the middle to latter
part of this week while it moves slowly west-northwestward to
northwestward, roughly parallel to the southern and southwestern
coasts of Mexico.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...70 percent.

[Yellow Evan]

GEFS and EPS showing two very different environments in the long range. EPS is more akin to a central based Nino while the GEFS favors rising motion from 80-90W and subsequent easterly shear to west of the -VP cell.