Potential System South of Cabo Verde Islands (Is Invest 91L)

This is the general tropical discussion area. Anyone can take their shot at predicting a storms path.

Moderator: S2k Moderators

Forum rules

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

Help Support Storm2K
Message
Author
User avatar
Hurricaneman
Category 5
Category 5
Posts: 5595
Age: 37
Joined: Tue Aug 31, 2004 3:24 pm
Location: central florida

Re: Potential System South of Cabo Verde Islands

#21 Postby Hurricaneman » Sat Aug 12, 2017 11:10 pm

cycloneye wrote:But again has two competing vorts to start.

Image

I can believe the GFS with the competing vortices but am a little on the side that the GFS is possibly giving convective feedback and overdeveloping this feature like it did with 99L
1 likes   

User avatar
Siker
Category 2
Category 2
Posts: 600
Age: 20
Joined: Thu Oct 25, 2012 7:36 pm
Location: New Orleans, LA / Williamstown, MA

Re: Potential System South of Cabo Verde Islands

#22 Postby Siker » Sat Aug 12, 2017 11:13 pm

00z CMC pretty much identical to the GFS at 72 hours FWIW.
0 likes   
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

User avatar
Siker
Category 2
Category 2
Posts: 600
Age: 20
Joined: Thu Oct 25, 2012 7:36 pm
Location: New Orleans, LA / Williamstown, MA

Re: Potential System South of Cabo Verde Islands

#23 Postby Siker » Sat Aug 12, 2017 11:20 pm

UKMET continues to show nothing.
1 likes   
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

User avatar
abajan
Category 5
Category 5
Posts: 3213
Joined: Sun Sep 07, 2003 5:10 am
Location: Rendezvous Hill, Christ Church, Barbados

Re: Potential System South of Cabo Verde Islands

#24 Postby abajan » Sat Aug 12, 2017 11:21 pm

GFS has been showing a hurricane passing uncomfortably close to the Leeward Islands next Saturday morning, for the last few runs now. :eek:

Image
0 likes   

RL3AO
Moderator-Pro Met
Moderator-Pro Met
Posts: 15961
Joined: Thu Jun 14, 2007 10:03 pm
Location: Raleigh, NC
Contact:

Re: Potential System South of Cabo Verde Islands

#25 Postby RL3AO » Sat Aug 12, 2017 11:26 pm

If the GFS is anywhere near correct, it will put the Atlantic above average single-handily for some time.
0 likes   
https://twitter.com/codyyeary
Graduate student at NC State studying tropical waves

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#26 Postby USTropics » Sat Aug 12, 2017 11:42 pm

Hurricaneman wrote:
cycloneye wrote:But again has two competing vorts to start.


I can believe the GFS with the competing vortices but am a little on the side that the GFS is possibly giving convective feedback and overdeveloping this feature like it did with 99L


It's most likely overzealous on how fast this system will organize, but genesis isn't a result of convective feedback in this instance. The other models (including the earlier run of the ECMWF) are forecasting a strong vortex signature to exit the African coast and interact with the persistent monsoonal trough in the CATL that extends from 31N50W to 27N56W.

For those that aren't exactly sure what convective feedback is (since it gets thrown around here so often), here is a quick explanation:

Convective feedback usually occurs when the model develops a local bulls eye of convection and heavy QPF over a very short distance and time. The model then overcompensates, as the convective parameter causes a large amount of latent heat to be released into the atmosphere. This produces a maximum of vertical velocity around 500mb over the QPF bulls eye. This also usually results in the development of a local upper-level jet maximum and a small intense bulls eye of vorticity.
Last edited by USTropics on Sat Aug 12, 2017 11:51 pm, edited 1 time in total.
0 likes   

User avatar
Hurricaneman
Category 5
Category 5
Posts: 5595
Age: 37
Joined: Tue Aug 31, 2004 3:24 pm
Location: central florida

Re: Potential System South of Cabo Verde Islands

#27 Postby Hurricaneman » Sat Aug 12, 2017 11:46 pm

The last few runs of the GFS seem to be trending towards a stronger ridge with the trough retreating causing a thumb ridge but also trending south after 156 hrs which is not a trend I want to see as any real shifts could bring the US into the equation
0 likes   

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#28 Postby USTropics » Sun Aug 13, 2017 12:23 am

Always take these long range forecasts with a grain of doubt (especially this year), but the CMC and GFS model have a pretty significant storm through 240 hours.

00z GFS:
Image

00z CMC:
Image
0 likes   

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#29 Postby USTropics » Sun Aug 13, 2017 12:27 am

A significant number of GFS ensemble members are concentrated over or just north of the islands:

Image
0 likes   

User avatar
AubreyStorm
Tropical Storm
Tropical Storm
Posts: 103
Age: 36
Joined: Fri Jun 16, 2017 6:21 pm
Location: Chicago, USA

Re: Potential System South of Cabo Verde Islands

#30 Postby AubreyStorm » Sun Aug 13, 2017 12:57 am

He we go!
Image
1 likes   
The posts are NOT an official forecast. Please REFER to the NHC and NWS for official forecasts and products.

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#31 Postby USTropics » Sun Aug 13, 2017 1:00 am

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Aug 13 2017

1. A tropical wave that has just emerged off the west coast of Africa
is forecast to move westward over the next couple of days and merge
with a broad area of low pressure located southwest of the Cabo
Verde Islands. Thereafter, environmental conditions are expected to
be conducive for gradual development of the system while it moves
westward to west-northwestward at 10 to 15 mph over the open
tropical Atlantic Ocean.

* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.
1 likes   

User avatar
Siker
Category 2
Category 2
Posts: 600
Age: 20
Joined: Thu Oct 25, 2012 7:36 pm
Location: New Orleans, LA / Williamstown, MA

Re: Potential System South of Cabo Verde Islands

#32 Postby Siker » Sun Aug 13, 2017 1:23 am

It looks like the Euro doesn't merge the two waves this run?
0 likes   
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#33 Postby USTropics » Sun Aug 13, 2017 1:46 am

The 00z ECMWF has delayed development, but shows a system just north of the Leeward Islands by 168 hours:

Image
0 likes   

User avatar
AtlanticWind
Category 4
Category 4
Posts: 961
Age: 59
Joined: Sun Aug 08, 2004 9:57 pm
Location: Plantation,Fla

Re: Potential System South of Cabo Verde Islands

#34 Postby AtlanticWind » Sun Aug 13, 2017 1:48 am

USTropics wrote:The 00z ECMWF has delayed development, but shows a system just north of the Leeward Islands by 168 hours:


A threat to the U.S and the islands on this euro run.
0 likes   

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#35 Postby USTropics » Sun Aug 13, 2017 1:49 am

One other environmental variable that we'll really have to watch is the forecasted strengthening of the Bermuda-Azores high. This will increase wind flow to the north, most likely accelerate movement speed of our AOI, and increase SAL spread (although there CURRENTLY appears to be a somewhat favorable absence of SAL between the CATL wave and the EATL wave).
0 likes   

USTropics
Category 5
Category 5
Posts: 1135
Age: 29
Joined: Sun Aug 12, 2007 3:45 am
Location: Deltona, Florida

Re: Potential System South of Cabo Verde Islands

#36 Postby USTropics » Sun Aug 13, 2017 2:01 am

Currently the only model not showing development is the UKMET:

00z ECMWF at 240 hours:
Image

00z GFS at 240 hours:
Image

00z CMC at 240 hours:
Image[/quote]
0 likes   

User avatar
Siker
Category 2
Category 2
Posts: 600
Age: 20
Joined: Thu Oct 25, 2012 7:36 pm
Location: New Orleans, LA / Williamstown, MA

Re: Potential System South of Cabo Verde Islands

#37 Postby Siker » Sun Aug 13, 2017 2:02 am

USTropics wrote:Currently the only model not showing development is the UKMET:


If the UKMET is showing Euro like development we wouldn't actually see it on the text product because it's beyond 144 hours. Need to see graphics.

Edit: It has a further north, stronger version of the Euro.

Image
0 likes   
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

User avatar
Kingarabian
S2K Supporter
S2K Supporter
Posts: 7874
Joined: Sat Aug 08, 2009 3:06 am
Location: Honolulu, Hawaii

Re: Potential System South of Cabo Verde Islands

#38 Postby Kingarabian » Sun Aug 13, 2017 3:42 am

Would be pretty agitating if the models end up doing an about face.
0 likes   
Image

bamajammer4eva
Category 2
Category 2
Posts: 775
Joined: Sun Apr 18, 2010 3:21 am
Location: Daleville, AL

Re: Potential System South of Cabo Verde Islands

#39 Postby bamajammer4eva » Sun Aug 13, 2017 4:03 am

Kingarabian wrote:Would be pretty agitating if the models end up doing an about face.


No way that would happen HA HA
:na:
0 likes   

User avatar
AtlanticWind
Category 4
Category 4
Posts: 961
Age: 59
Joined: Sun Aug 08, 2004 9:57 pm
Location: Plantation,Fla

Re: Potential System South of Cabo Verde Islands

#40 Postby AtlanticWind » Sun Aug 13, 2017 4:38 am

06Z GFS shows a tropical storm by Monday morning.
0 likes   


Return to “Talkin' Tropics”

Who is online

Users browsing this forum: AutoPenalti, Blown Away, chris_fit, CourierPR, crownweather, CyclonicFury, gatorcane, Google Adsense [Bot], Hurricaneman, jlauderdal, Torgo, UFCountryMama85, weatherwindow and 65 guests