Strong Tropical Wave WSW of CV Islands (INVEST 94L is up)

[Siker]

Text output from the 00z UKMET:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 78 HOURS
FORECAST POSITION AT T+ 78 : 9.8N 33.9W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 04.07.2017 84 10.0N 34.3W 1012 25
0000UTC 05.07.2017 96 11.9N 35.6W 1011 29
1200UTC 05.07.2017 108 13.6N 37.7W 1010 32
0000UTC 06.07.2017 120 15.3N 40.5W 1012 34
1200UTC 06.07.2017 132 16.7N 44.0W 1011 33
0000UTC 07.07.2017 144 17.3N 47.6W 1011

[Nimbus]

This one has a pretty good roll to it but the dry air/SAL usually keeps development chances low till about -50W this time of year. They leave out "IF IT DEVELOPS AT ALL"? from the text output of the 00z UKMET or is the model going to be that good with this one?

[AutoPenalti]

This one has a pretty good roll to it but the dry air/SAL usually keeps development chances low till about -50W this time of year. They leave out "IF IT DEVELOPS AT ALL"? from the text output of the 00z UKMET or is the model going to be that good with this one?

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sat Jul 1 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A tropical wave located about 400 miles southwest of the Cabo
Verde Islands is producing an area of disorganized showers and
thunderstorms. Environmental conditions are expected to be
conducive for gradual development during the next several days
while the disturbance moves westward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

Forecaster Stewart

Stewart should have went with "...development, if any, should be slow to occur..."

Maybe the next guy will change it at the 2pm TWO, unless they see something that we don't.

[RL3AO]

The 12Z GFS seems like a realistic scenario. Development north of the islands and intensification while curving out to sea. Obviously, I'm not taking a 300 hr forecast as fact, but it matches what you'd expect from climatology.

[TheStormExpert]

I'm really curious to see what the Euro shows in a little over an hour.

Either way there has been more troughs swinging through the Eastern U.S. as opposed to last summer. OTS seems like it's more than 50% likely to happen.

[AutoPenalti]

I'm really curious to see what the Euro shows in a little over an hour.

Either way there has been more troughs swinging through the Eastern U.S. as opposed to last summer. OTS seems like it's more than 50% likely to happen.

We still have troughs at this time of year? Is that based on climo?

[RL3AO]

I'm really curious to see what the Euro shows in a little over an hour.

Either way there has been more troughs swinging through the Eastern U.S. as opposed to last summer. OTS seems like it's more than 50% likely to happen.

We still have troughs at this time of year? Is that based on climo?

June was a pretty clear trough east/ridge west month. Hence the record heat in the SW US.

[cycloneye]

2 PM:10%-40%

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sat Jul 1 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

A tropical wave located about 450 miles southwest of the Cabo
Verde Islands continues to produce a broad area of disorganized
showers and thunderstorms. Environmental conditions are expected
to be conducive for gradual development during the next several
days while the disturbance moves westward at about 10 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...40 percent.

$$
Forecaster Stewart

[TheStormExpert]

I'm really curious to see what the Euro shows in a little over an hour.

Either way there has been more troughs swinging through the Eastern U.S. as opposed to last summer. OTS seems like it's more than 50% likely to happen.

We still have troughs at this time of year? Is that based on climo?

June was a pretty clear trough east/ridge west month. Hence the record heat in the SW US.

http://i.imgur.com/FdyUtxE.gif

You can also see how the Bermuda High noses south and west which explains why the second half of the month here in S. FL featured drier than normal conditions along the SE coast.

[weathaguyry]

Invest soon?

[TheStormExpert]

Hmmm... I see the 2pm TWO raised percentages to 10/40% maybe we'll see an invest by tomorrow morning at the latest I'd think.

[floridasun78]

look nhc seen models want form area plus more modles picking up after euro pick up it too that put nhc say let bring circle back

[Nimbus]

look nhc seen models want form area plus more modles picking up after euro pick up it too that put nhc say let bring circle back

4th of July is on Tuesday this year since there is no emergency maybe they take Monday off?

The short term pattern looks like it would preserve any low level structure against shear..

"Generally
moderate trades will continue around the southern periphery of
this high over the Atlantic from 10n and 25n between 30w and 50w
through the next 24-48 hours."

[RL3AO]

ECMWF in 96 hours.

[gfsperpendicular]

This doesn't look very impressive...

[TheStormExpert]

12z Euro less enthusiastic than the 00z run.

[RL3AO]

Let's take a look at the ingredients

Positives For Development:

• SSTs - Okay. Right on the tight SST gradient. GFS developing the system around 10 to 12°N.
• http://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_sst_atltropics_1.png
• Westerly 850mb anomalies south of 10°N (actually westerly winds) which supports low level convergence
• http://i.imgur.com/VsK3yfA.png
• Easterly 200mb flow on the south side of a upper ridge. Leads to low shear in the MDR.
• http://i.imgur.com/S3MapTz.png
• http://i.imgur.com/BFaX9Kb.png
• Envelope of above average water vapor associated with the wave
• http://i.imgur.com/69WOFXB.png
  
  Negatives for Development:
• Any deep convection may pull in dry air from the north
• http://i.imgur.com/3xdPmoS.png
• Suppressed MJO over the Atlantic
• https://i.imgur.com/z08m8Ud.png
• Well...it's July 1st.

[cycloneye]

More positives and yeah is July 1.

[AutoPenalti]

Let's take a look at the ingredients

Positives For Development:

• SSTs - Okay. Right on the tight SST gradient. GFS developing the system around 10 to 12°N.
• http://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_sst_atltropics_1.png
• Westerly 850mb anomalies south of 10°N (actually westerly winds) which supports low level convergence
• http://i.imgur.com/VsK3yfA.png
• Easterly 200mb flow on the south side of a upper ridge. Leads to low shear in the MDR.
• http://i.imgur.com/S3MapTz.png
• http://i.imgur.com/BFaX9Kb.png
• Envelope of above average water vapor associated with the wave
• http://i.imgur.com/69WOFXB.png
  
  Negatives for Development:
• Any deep convection may pull in dry air from the north
• http://i.imgur.com/3xdPmoS.png
• Suppressed MJO over the Atlantic
• https://i.imgur.com/z08m8Ud.png
• Well...it's July 1st.

On paper you could see that the positive outweighs the negatives but in reality it seems like this won't really get going until it enters the carribean, I think.

[RL3AO]

On paper you could see that the positive outweighs the negatives but in reality it seems like this won't really get going until it enters the carribean, I think.

Except the negatives are really big negatives. TC genesis in the MDR in early July is fairly rare. TC genesis during a strongly suppressed MJO is rare. Bret forming when and where it did was impressive. If we get Don east of 50W in early July with a strongly suppressed MJO, then that's just more writing on the wall for peak season IMO.