Tropical Wave in Central Caribbean

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
254 PM AST FRI JUL 27 2012


MODELS SEEM TO HAVE TRENDED FASTER WITH SECOND TROPICAL WAVE
CURRENTLY ALONG 40W. ASSOCIATED WEATHER LOOKS TO ARRIVE BY
DAYBREAK MON ACROSS THE EAST...USVI AND ANEGADA PASSAGE. TC
DEVELOPMENT IS NOT EXPECTED BUT REGARDLESS OF DEVELOPMENT...WAVE
WILL BRING VERY ACTIVE WEATHER MON-TUE WITH HEAVY RAIN POTENTIAL.
DEEP MOISTURE LINGERS FOR SVRL DAYS AFTER WAVE PASSAGE WITH WET
PATTERN EXPECTED TO PERSIST THRU FRI WITH SIG IMPROVEMENT TO THE
WX EXPECTED BY NEXT WEEKEND.

[Blown Away]

12z Euro seems to bring a weak storm to SFL and GFS keeps 07L as a wave as it continues to move it over all the big islands. Still think this wave could develop if it can miss the big island mountains.
http://raleighwx.americanwx.com/models/ ... _loop.html

[floridasun78]

my question is models picking up afica dust well? because you can see dry air front of it

[NDG]

12z Euro seems to bring a weak storm to SFL and GFS keeps 07L as a wave as it continues to move it over all the big islands. Still think this wave could develop if it can miss the big island mountains.
http://raleighwx.americanwx.com/models/ ... _loop.html

This ECMWF run shows that it will be an open strong wave with a good vorticity, not a weak storm.

[Blown Away]

Amazing how consistent the GFS/Euro have been moving this wave over PR, DR, and Cuba and pushing it towards SFL/SE GOM area. 18z GFS no different, keeps this system as a strong wave and interacts w/ all the big islands, does appear like the low wants to deepen as it nears the tip of Florida. 18z GFS has a second system that develops into a weak storm then gets torn apart following the same track as Pouch 07 over the big islands, but does end up moving into the central Gulf coast. America's heartland could use a tropical system bringing some rain!!
http://raleighwx.americanwx.com/models/ ... SLoop.html

Little blow up of convection from our wave, let's see if it can sustain??


http://www.ssd.noaa.gov/goes/east/tatl/loop-avn.html

http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html
Fighting dry air for sure.
http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html

[Aric Dunn]

Thats a sign there is increasing convergence. it will likely collapse and rebuild many times until the mid levels dry air/ sal improve from the convection.

[Blown Away]

12z Nogaps likes Pouch 07 and has it go over PR and miss the big islands just to the North and deepens the low in the SE Bahamas.
http://raleighwx.americanwx.com/models/ ... sLoop.html

[NDG]

This is the largest TW in size so far this season, IMO, though it lacks convection it has a good structure, it just needs to get into a better environment, and if it can end up north of the greater Antilles, it will raise our eyebrows up.

http://tropic.ssec.wisc.edu/real-time/m ... t72hrs.gif

[Blown Away]

I know it's Nogaps, but the 12z run goes WNW over PR and misses the big islands then seems to find better conditions and begins to deepen at the end of the run. Also, Nogaps likes our next wave in the Central Atlantic!

[cycloneye]

Aric,if convection persists they may tag it.

[Blown Away]

JB still watching and tweeting about our wave.



NDG, great point, it does have good structure.

[NDG]

Even looking at the IR sat pix & limited convection it has a great organization look to it.

[Aric Dunn]

Yeah if convection can build enough tonight and maintain at least somewhat intact they might tag it tomorrow morning. then given its current structure it would not take to long to organize at the surface.

[SFLcane]

Dont really see this large TW doing much with all this dry/stable air just about everywere.

Great loop here shows some increase t-storms this evening. http://hoot.metr.ou.edu/satellite/GOES-E/Trop/IR

[Fego]

http://rammb.cira.colostate.edu/ramsdis ... _floater_1

RAMDIS shows a very clear an updated loop of this tropical wave. Looking at it, no wonder the 8:00pm TWD mention again that it has a llc.

[Fego]

Dont really see this large TW doing much with all this dry/stable air just about everywere.

Great loop here shows some increase t-storms this evening. http://hoot.metr.ou.edu/satellite/GOES-E/Trop/IR

That's a very good loop. Look how some clouds begin to grow in the upper left side around the new convection.

[USTropics]

What's a high-amplitude wave?

In essence a high amplitude wave has an enhanced structural presence, with a sharper, well-defined, and more elongated wave axis. Typically a high amplitude wave will have an enhanced moisture envelope that accompanies it. When observing a high amplitude wave from satellite images, distinct inverted V patterns in the cloud formation are evident. Contrary to this would be a low amplitude wave, which is structurally weak, typically void of any moisture, and can be difficult to discern on satellite.

Easterly waves start out as small amplitude waves, producing only mild rain showers during their conception. As these waves traverse over Africa and emerge off the coast, high-altitude winds will aid in amplifying the waves when atmospheric conditions are favorable (i.e. at certain locations in the easterly wave, wind speeds up or slows down causing stretching (divergence) or piling up (convergence) of the air parcels in the wave), forming powerful thunderstorms and gale force winds.

[christchurchguy]

It seems to be moving quite fast

[ROCK]

I see the LLC but its got a rough road ahead with all the stable air around it.

[floridasun78]

but models are picking on this area to get invest upgrade soon