ATL : INVEST 90L - DISCUSSION

[thetruesms]

People still bother watching TWC? There's almost nothing on there you can't get better or faster online

[Blown Away]

You can see the convection from the E wave is now reaching 90L's broad center from the SE. This convection kinda flattens as is reaches 90L's circulation?

[ConvergenceZone]

Thanks HURAKAN and thetrusms for the clarrification on which ones may merge....

[KWT]

The models really aren't as keen as they were a few days ago on this wave, most now don't do anything more then a sharp wave/weak depression. I'd imagine the models are sniffing out on a possible ULL diving south-westwards through the C.Atlantic but these features shouldn't be trusted really.

[ConvergenceZone]

The models really aren't as keen as they were a few days ago on this wave, most now don't do anything more then a sharp wave/weak depression. I'd imagine the models are sniffing out on a possible ULL diving south-westwards through the C.Atlantic but these features shouldn't be trusted really.

Hmmm, then maybe it will be another couple of weeks then before we get Colin?..I was thinking something by August 7th, but I guess we'll have to see if we need to push that date further back.

[KWT]

Too early to tell, could easily get Colin, even if its short lived, based on what the models are doing, wouldn't take much of a change to get something as we saw with Bonnie where all the models called for an open wave but it did manage to briefly hold something together.

Besides as I've said before I don't put any faith in the upper level forecasts!

[Riptide]

It is impossible to simulate something that has not developed yet.

[ConvergenceZone]

KWT, I've always wondered how models can even predict anyway? How is that a model able to see something way in the future that our Mets can't? That's always fascinated me....

[thetruesms]

It is impossible to simulate something that has not developed yet.

sarcasm, I hope?

[Aric Dunn]

It is impossible to simulate something that has not developed yet.

well actually thats is true in someways for this situation.... the models dont develop anything because they dont know what is going on out there.. new data is being inputted that has two waves merging and that is very complicated. if you recall before it was 90L the models were not calling for a merger and they had a stronger system. most do not have the resolution to forecast that detail. so when the data was inputted the became confused.. lol

[cycloneye]

This is what the NWS in San Juan sees at this time about what may unfold late next week.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
312 PM AST FRI JUL 30 2010

THE TUTT LOW TO OUR NORTHEAST IS EXPECTED TO RETROGRADE WESTWARD
EARLY NEXT WEEK...WITH A LOW LEVEL TROUGH OR REFLECTION OF THIS
TUTT EXPECTED TO BRING AN INCREASE IN MOISTURE ACROSS THE VI AND
SECTIONS OF PUERTO RICO BY MONDAY AFTERNOON AND TUESDAY. THE MOST
INTERESTING FEATURE OVER THE NEXT SEVEN DAYS IS THE POTENTIALLY
STRONG TROPICAL WAVE...THAT AT THIS TIME HAS A LOW CHANCE OF
DEVELOPING INTO A TROPICAL CYCLONE...EXPECTED TO REACH THE LOCAL
ISLANDS TOWARD THE MIDDLE TO END OF NEXT WEEK. STILL MUCH
UNCERTAINTY...BUT EITHER WAY...EXPECT A SIGNIFICANT INCREASE IN
SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE LOCAL ISLANDS BY NEXT
WEDNESDAY OR THURSDAY AS THIS WAVE APPROACHES THE LOCAL ISLANDS.

[Riptide]

It is impossible to simulate something that has not developed yet.

sarcasm, I hope?

No, I'm just grasping for straws.

Only joking my friend. All kidding aside, I don't see any inhibiting factors for development in the next 36 hours. This TW is probably under some of the best conditions in the tropical Atlantic, shear is probably under 5 kts now or approaching that mark. It is that imaginary ULL that could screw something up post-48 hours I think. Wouldn't be surprised if 90L was a depression by Sunday.

[thetruesms]

KWT, I've always wondered how models can even predict anyway? How is that a model able to see something way in the future that our Mets can't? That's always fascinated me....

Simply because our poor brains are unable to quickly solve the necessary PDEs to quantitatively describe the motion of the atmosphere accurately. We can quickly figure things in a qualitative sense, but in marginal cases where you really need the actual numbers to be calculated to determine what's going to happen, you need a computer to crunch everything in enough time.

[KWT]

KWT, I've always wondered how models can even predict anyway? How is that a model able to see something way in the future that our Mets can't? That's always fascinated me....

Its real complicated thats for sure, I'm not sure I could give you a 'proper' answer, I'm sure there is a pro met out there that could give a good answer to that sort of question!

What I will say is the models resolutions, esp the GFS/ECM should allow the models to have a better grasp on possible strength of systems, at least on the lower end of the scale compared to say 2004-2006 era due to the upgrades.

Anyway the next 24-48hrs look fairly quiet but I do think there is a pretty good shot by 72-96hrs of something getting going. There appears to be some higher shear aloft to the north and from the looks of things the system really can't gain too much latitude to survive...but its a really messy set-up for sure. Of course the shear may not even occur yet so we will wait and see!

[Riptide]

KWT, I've always wondered how models can even predict anyway? How is that a model able to see something way in the future that our Mets can't? That's always fascinated me....

Simply because our poor brains are unable to quickly solve the necessary PDEs to quantitatively describe the motion of the atmosphere accurately. We can quickly figure things in a qualitative sense, but in marginal cases where you really need the actual numbers to be calculated to determine what's going to happen, you need a computer to crunch everything in enough time.

Our brains aren't "wired" to make such calculations anyhow even though it is theoretically possible. We only use 10-15 % of our brain capacity.

Apparently, That gap is large enough to separate average from genius.

[KWT]

Looks to me like there maybe the first signs of a ULL forming:

http://www.ssd.noaa.gov/goes/east/catl/flash-wv.html

ULL maybe forming to the NW of the current invest, obviously it has a little bit of space but I can only assume if the ULL is there and it strengthens, its going to shear the E.Atlantic region...hence why the models don't do much...

[Riptide]

If ULL's can develop, how do they dissipate?

[StormClouds63]

Any chance that the peak of the 2010 hurricane season will be later than September 10th? Perhaps closer to September 20th, which might account for the somewhat slow start and marginal conditions currently being seen in the Atlantic tropical basin. I know one of the analog years, 1969, would fit that profile.

90L not looking nearly as impressive. If it does develop, a very slow organization likely. Bonnie appears it for July.

[KWT]

Need more time to make sure but that'd certainly explain why the models aren't really all that keen on development past 72-96hrs....

[coreyl]

Looks to me like there maybe the first signs of a ULL forming:

http://www.ssd.noaa.gov/goes/east/catl/flash-wv.html

ULL maybe forming to the NW of the current invest, obviously it has a little bit of space but I can only assume if the ULL is there and it strengthens, its going to shear the E.Atlantic region...hence why the models don't do much...

Crazy question but, wouldn't the ridge push the ULL or whatever that is back to the west far in front of 90L?