2017 EPAC Season

[gatorcane]

The GFS is showing again that the remnants crossover into the Caribbean but encounters hostile conditions and struggles to redevelop.

GFS is showing development with about 4 days now so I imagine the NHC will need to issue an outlook maybe today that development is possible within 5 days (maybe even likely looking at the GFS and ECMWF).

Little surprised about development as we are still about 10 days before the EPAC season starts but the two big models continue to insist it will development and have near ideal conditions.

[cycloneye]

 https://twitter.com/TropicalTidbits/status/860202851569676288

[Yellow Evan]

12z ECMWF stalls it offshore and delays everything. Might be back to a classic recurve in a few runs, but I'm getting less bullish on this possible system.

[TheStormExpert]

12z GFS has landfall at El Salvador/Honduras on May 12. It moves slowly since formation on May 8 as steering is weak.

That's pretty far South and East in Central America for an East Pacific system to be making landfall.

[cycloneye]

12z ECMWF continues with a powerful Hurricane but differs with GFS on track.

[NDG]

12z GFS has landfall at El Salvador/Honduras on May 12. It moves slowly since formation on May 8 as steering is weak.

http://i.imgur.com/jijTzlR.png

That's pretty far South and East in Central America for an East Pacific system to be making landfall.

Not an uncommon track for this time of the year.

[Yellow Evan]

12z ECMWF stalls it offshore and delays everything. Might be back to a classic recurve in a few runs, but I'm getting less bullish on this possible system.

Take that back,



Likely headed for landfall looking at the setup. Jova 11, but further south.

[cycloneye]

Euro has something in 72 hours, perhaps this is the area starting to show signs? 90W, 10N

https://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20HURRICANE&lat=10&lon=-95&info=vis&zoom=2&width=1024&height=768&type=Animation&quality=92&palette=ir1.pal&numframes=7&mapcolor=gray

In the very beginning stage.

[cycloneye]

EricBlake12
@pppapin If weren't so tied into the MJO/CCKW coming through, I'd be more skeptical but given the forcing, little reason to doubt it other than climo

 https://twitter.com/EricBlake12/status/860246177211703296

[gatorcane]

The ECMWF and GFS continue to have vastly different solutions with the ECMWF moving this west and the GFS pulling it north into the Caribbean. Will be interesting to see what happens. One thing is for sure, convection is on the increase:

[cycloneye]

It would be a not good situation for Central America if what GFS has is a slow moving system making landfall in El Salvador/Honduras.

[NDG]

The ECMWF and GFS continue to have vastly different solutions with the ECMWF moving this west and the GFS pulling it north into the Caribbean. Will be interesting to see what happens. One thing is for sure, convection is on the increase:

https://s2.postimg.org/rp6aw5msp/avn-l.jpg

My thinking is right up the middle between these two is what is usually the right solution at the end.

[cycloneye]

Now what? 12z ECMWF almost doesn't develop.

[Florida1118]

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1130 AM PDT Fri May 5 2017

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

1. A broad area of low pressure is expected to form by early next week
over the far eastern North Pacific Ocean to the south of El Salvador
and Guatemala. Environmental conditions are forecast to be favorable
for gradual development of the system through the middle of next
week while it moves slowly toward the northwest or north. The next
Special Tropical Weather Outlook will be issued by 12 PM PDT
Saturday afternoon.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Stewart

[Yellow Evan]

12z GFS and 6z parallel GFS bring this into El Salvador as a potent hurricane.

12z ECMWF rolling in and has it turning west out to sea with much more agreement on short-term motion than the GFS.

[gatorcane]

If you look closely, it looks the last two runs of the ECMWF develop a second low and turns it north with a similar track to the GFS's first low it develops. Looks like we will have a big monsoon gyre / broad low where development is possible anywhere in the gyre.

[Yellow Evan]

12z ECMWF has this getting blocked by a ridge and make a U turn at the end of the run. Synoptic pattern is similar, the storm forms in a similar spot, but weaker, and the ridge is a little stronger, so it gets blocked.

[gatorcane]

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1130 AM PDT Fri May 5 2017

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

1. A broad area of low pressure is expected to form by early next week
over the far eastern North Pacific Ocean to the south of El Salvador
and Guatemala. Environmental conditions are forecast to be favorable
for gradual development of the system through the middle of next
week while it moves slowly toward the northwest or north. The next
Special Tropical Weather Outlook will be issued by 12 PM PDT
Saturday afternoon.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Stewart

[Yellow Evan]

Classic GFS overdoing the monsoonal gyre setup.

[TheStormExpert]

00z Euro barely develops it now into a weak/moderate TS then kills it a few days later. The GFS blows this up into a decent hurricane still. In my opinion this is likely another case of convective feedback with the models, development chances are likely 50/50 at very best and that's probably being too generous.