ATL: FRANKLIN - Remnants - Discussion

[cycloneye]

12z HWRF goes bonkers.

[BZSTORM]

Board awfully quiet for a gathering tropical storm in the Caribbean.

Central America / BOC / Mexico storms don't get a lot of interest since few people live in these areas on this board.

I agree this one is looking better and should have higher development chances than 99L.

well were watching closely in Belize, our weather has been running hotter than normal since April, humidity has been really high as well for few days thanks to heavy night rainfalls and I'm told by tour guides sea temps are pretty warm as well, not to mention any lagoon/marshlands have pretty warm water in them right now, so any drift on models that put it near Belize city or any of the coastal marshlands could cause system to organize rapidly it only would need to slow and stall to do that. Water tables are very high so even a depression could cause flash flood issues here right now. So yes were are watching.

[GCANE]

Here's a view of the shear gradient.
Blue line is the axis.
Its firing right on the edge.
A few hot towers could get this spinning.

GCane (or anybody else who'd like to chime in) -- Could you take a minute to explain the relationship between your observation of the shear axis and the enhanced convection below it? Is it because the shear axis is acting like a jet in this situation? High-volume ventilation?

Thanks in advance!

Wind shear helps the development of strong updrafts. The convection from this however doesn't last more than a few hours.
Here's a good link that explains it more.

http://en.wikipedia.org/wiki/Mesoscale_ ... ive_system

[cycloneye]

2 PM TWO 40%-60%

Showers and thunderstorms associated with a strong tropical wave
located over the central Caribbean Sea are beginning to show some
signs of organization, and satellite wind data indicate that the
wave is producing a small area of winds that are just below tropical
storm force. Additional development of this system is possible
while it moves west-northwestward at 10 to 15 mph, and a tropical
depression or tropical storm could form over the northwestern
Caribbean Sea before it reaches the Yucatan peninsula late Monday or
Tuesday. Even if formation does not occur before the system
reaches the Yucatan peninsula, a tropical depression or tropical
storm could form over the Bay of Campeche during the middle part of
next week. Development would likely not occur if the system moves
inland over Central America and southeastern Mexico and does not
re-emerge over water. An Air Force Reserve reconnaissance aircraft
is scheduled to investigate this system tomorrow afternoon, if
necessary. Interests along the coasts of Honduras, Belize, and the
Yucatan peninsula of Mexico should monitor the progress of this
disturbance.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...60 percent.

[GCANE]

A few black dots (towers) firing in the large red blob (cirrus canopy) around 14N 74W,
Obviously building a large MCV here.

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

[tropicwatch]

Kind of surprised with only 60% during five day time frame.

[Craters]

GCane (or anybody else who'd like to chime in) -- Could you take a minute to explain the relationship between your observation of the shear axis and the enhanced convection below it? Is it because the shear axis is acting like a jet in this situation? High-volume ventilation?

Thanks in advance![/quote]


Wind shear helps the development of strong updrafts. The convection from this however doesn't last more than a few hours.
Here's a good link that explains it more.

http://en.wikipedia.org/wiki/Mesoscale_ ... ive_system[/quote]

Great -- thanks!

[wxman57]

Kind of surprised with only 60% during five day time frame.

I'm not surprised. If they went higher, at least in the 48hr time frame, they'd have to start potential tropical cyclone advisories, as the system will be affecting land within 48 hrs. I'm sure that fact will govern how high they go within 48hrs. I think I'd go 60/90 now.

[RL3AO]

Kind of surprised with only 60% during five day time frame.

I'm not surprised. If they went higher, at least in the 48hr time frame, they'd have to start potential tropical cyclone advisories, as the system will be affecting land within 48 hrs. I'm sure that fact will govern how high they go within 48hrs. I think I'd go 60/90 now.

I still think they will hold off PTC advisories until genesis is almost certain (at least 90 within 48 hrs).

[GCANE]

There is a small TUTT over Hispaniola that is filled with mid-level moisture.
And of course the ULL at 24N 60W.
Likely the TUTT will collapse this afternoon when thunderstorms fire over the island due to their updraft.
That could open it up for the ULL to create a poleward outflow channel for 90L.

http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html

[Siker]

12z Euro gets down to 1005mb before crossing the Yucatán. Would be surprised not to see a hurricane out of this in the Gulf if it can organize like that before the Yucatán.

[GCANE]

Another CCW-Walking Tower.
Obviously heating up the core and coupling mid-layer vort down to the surface.

[BobHarlem]

Euro has a pretty solid system in the Bay of Campeche as it moves toward Southern Mexico. It looks like it'll ramp up right before the Yucatan landfall also. This run also has signs of life again for 99L.

[cycloneye]

[TheStormExpert]

Video discussion by Tropical Tidbits Levi Cowan.

 https://twitter.com/tropicaltidbits/status/893895793819750401

[cycloneye]

18z Best Track:

As of 18:00 UTC Aug 05, 2017:

Location: 14.1°N 77.1°W
Maximum Winds: 30 kt Gusts: N/A
Minimum Central Pressure: 1008 mb
Environmental Pressure: 1011 mb
Radius of Circulation: 120 NM
Radius of Maximum Wind: 90 NM

[Cpv17]

The Euro appears to be initializing the storm too far to the south. Once we actually have a closed area of low pressure for the models to initialize from then we'll have a much better idea of where this is headed.

[Steve]

I like the model concensus converging around an intensifying low pressure hitting SE Mexico provided it crosses the Yucatán far enough north where the circulation is at least 100 miles north of the Mexican BoC Coast. Models like that Texas perpendicular effect causing intensification at landfall. I doubt that it hits 2, but a midgrade TS through Cat 1 seems reasonable if it gets the water to work with. I'd give it about a 90% chance in 5 days of being Franklin. I realize that's way more aggressive than I usually am. But this one looks like a go.

[Sanibel]

Will it maintain or will lingering July shear knock it down?

[GCANE]

Lots of deep convection firing now.
Obviously a large updraft has formed.