Invest 91L E Windwards,Comments,Sat Pics,Models Thread #2

[Bailey1777]

Buoy 41041

Wind-ENE
Wind Speed-17.5
Gust-21.4
Pressure-29.90

[Derek Ortt]

just look at the low-cloud motions. if they are converging toward the center, we have convergence

[Bailey1777]

Simple enough. Thanks for answering Derek, I'm sure you get tired of the questions.

[cycloneye]

WHXX04 KWBC 072331
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST 91L

INITIAL TIME 18Z AUG 7

DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)

0 11.7 42.0 275./18.0
6 12.0 43.3 282./13.4
12 12.2 44.8 279./14.9
18 12.5 46.5 278./16.6
24 12.7 47.8 280./13.5
30 13.0 49.6 278./17.0
36 13.4 51.4 282./17.8
42 13.2 53.4 266./19.8
48 13.6 55.4 280./19.4
54 13.6 57.4 271./20.0
60 13.7 59.8 271./23.3
66 13.5 61.9 267./19.9
72 13.0 64.8 260./28.9
78 11.6 65.6 209./16.0

STORM DISSIPATED AT 78 HRS AT THE ABOVE PSN.


18z GFDL.

This 18z run of the GFDL gives 78 hours of life to 91L,a change from the 12z run which only gave 30 hours.

[Thunder44]

Is it just me or is this system looking more elongated or stretched out this evening?

[Bailey1777]

It is ugly. I think there's a really good spin underneath it all though.

[Derek Ortt]

the weakening of the vortex is the result of little convergence. the change in vorticity is reletaed ot the convergence, and when you dont have much, you lose the vorticity.

This could slowly devleop, but it could also open into a wave and a weak one at that in the not too distant future

[Bailey1777]

So if we have convergence then you would see more convection popping at the vortex itself is that correct?

[Derek Ortt]

if this had the same dynamics as Chris had, you'd see a healthy TS now, not a supttering and weakening tropical low

[Thunder44]

the weakening of the vortex is the result of little convergence. the change in vorticity is reletaed ot the convergence, and when you dont have much, you lose the vorticity.

This could slowly devleop, but it could also open into a wave and a weak one at that in the not too distant future

It does appear to be weakening at the moment.

[marcane_1973]

The disturbed area Northwest of Puerto Rico looks healthier and more interesting than 91L in my opinion. 91L looks terrible on satellite tonight. http://www.ssd.noaa.gov/goes/east/watl/avn-l.jpg

[Sanibel]

See if it shoots a new central convective burst. That'll mean it has something.

[wxman57]

See if it shoots a new central convective burst. That'll mean it has something.

That would be true. Convection draws inflow. Inflow aids convection. The mroe this continues, the more the pressure lowers. The more the pressure lowers, the greater the inflow. It's a positive feedback mechanism. The key is to get convection over the center to kick start it.

[Bailey1777]

WXMAN typically speaking how low doe's shear have to be for convection to stay with a system or is it dependent on the direction it's coming from.

[SouthFloridawx]

wxman57 do you think it's possible that besides the lack of low level convergence that the smaller Upper level low that I have indicated here has had an effect on the mid to upper level synoptics of this feature?

[cycloneye]

...SPECIAL FEATURE...
A 1009 MB ATLANTIC OCEAN LOW PRESSURE CENTER IS NEAR 12N42W
MOVING WEST NEAR 15 KT. THUNDERSTORM ACTIVITY IS CURRENTLY
LIMITED NEAR THE CENTER. A BAND OF CONVECTION IS W OF THE
CENTER...IS MOVING AWAY FROM THE CENTER...AND IS DISSIPATING.
FURTHER DEVELOPMENT TO A TROPICAL DEPRESSION IS POSSIBLE
TOMORROW WHEN THE SYSTEM MOVES OVER WARMER SEA TEMPERATURES.

8 PM Discussion.

[Recurve]

Come on, ULLs! Tear this puppy apart. Don't want no TCs getting north of Hispanola with a persistent ridge. No no.

Have to admit it, I'm a cheerleader for the other side. Like to see things go poof and have just tropical waves coming by. It's been a great normal to above rainy summer here, everything's lush, the broken trees are full of new growth. Let's keep this setup. Keep the ULLs or whatever is nearby working this season.

[Bailey1777]

In all our post today we never brought up the sea temps. in the area.

[destro34]

uhmmm!! i would not write this off, iam like the nhc....let us wait and see..when it get to 50 we will talk..till now do not worry...wait...

[Derek Ortt]

the SST's ar eplenty warm enough where its at for development. Over 27C