ATL: Ex COLIN - Discussion

[blazess556]

I just don't buy the east out to sea models on this one either. I also think once the trough lifts out the ridge turns Colin by then back more westward so anywhere from Central Florida up to SC is my hunch.

exactly my thoughts too. it won't feel the complete tug of the trough and then it will head west.

[KWT]

Yeah it is to do with the global wave pattern, I believe the higher the number of waves the more progressive the pattern, so for example you won't be stuck under the same trough for too long, vice versa. A 3-4 wave pattern (the lower number is pretty rare I believe) is a much slower pattern that is mor prone to holding solid.

ps, don't expect any long spells of WNW motion once it does gain latitude, once its at 27-30N, will probably only gain a few degrees more longtitude in the expected pattern aloft...of course that could end up being enough anyway.

[srainhoutx]

Very interesting part of discussion:

THE GFS-BASED SHIPS
INTENSITY MODEL IS FORECASTING THE SHEAR TO INCREASE TO MORE THAN
30 KT...WHICH WOULD NORMALLY RESULT IN WEAKENING OF A TROPICAL
CYCLONE. HOWEVER...THESE HIGH SHEAR VALUES MAY BE AN ARTIFACT OF
THE THE GFS HAVING MUCH STRONGER UPPER-LEVEL WINDS AS COMPARED TO
THE OTHER GLOBAL MODELS...AND ALSO DUE TO 500 KM RADIUS THAT THE
SHIPS USES IN COMPUTING SHEAR VALUES. IF THE DEPRESSION REMAINS
UNDERNEATH THE UPPER-LEVEL ANTICYCLONE RATHER THAN OUTRUNNING IT
...THEN THE CYCLONE WILL END UP STRONGER THAN THE OFFICIAL FORECAST
INDICATES.

I have been wondering about this part of the discussion. Perhaps more issues with the GFS? Time will tell, but if this is a function of a problem in the output, this does not bode well for future systems that will come along in the days ahead and future runs of that model regarding shear forecasts.

[HURAKAN]

anticyclone developing over TD #4

[Gustywind]

T.D. 4 organizes in the central Atlantic
M. Ressler, Lead Meteorologist, The Weather Channel
Aug. 2, 2010 4:50 pm ET
Tropical Depression 4 formed in the central Atlantic Monday morning. It is located 1270 miles east of the Lesser Antilles and moving west-northwest at 16 mph. This tropical depression could quickly become Tropical Storm Colin overnight. Right now, the forecast track takes this system northwestward into the western Atlantic, avoiding the islands of the Caribbean and the Bahamas mid to late week. The track could easily change so stay tuned!
East of the tropical depression, a strong tropical wave continues to produce thunderstorms and bears watching as well.

[jlauderdal]

A very interesting discussion make no mistake.

I remember someone else mention that the SHIPS maybe overdoing the shear levels due to the set-up, interesting to see the NHC make the same point!

Shear forecasts and intensity forecasts are just about as mysterious as woman. We have seen shear and intensity forecasts bust many times so beware.

[Nimbus]

A 3-4 wave pattern (the lower number is pretty rare I believe) is a much slower pattern that is mor prone to holding solid.

With a five wave pattern there are more short waves but they move out quicker and don't dig as far south.

ps, don't expect any long spells of WNW motion once it does gain latitude, once its at 27-30N

I'm using 15N -50W as a benchmark, if it crosses north of that and I will sleep a little better.

[KWT]

Ah there it is Hurakan, you can tell shea ris light with it as it'd have never developed the ball shape in the first place....

Nimbus, yeah thats one benchmark I'm keeping a close eye on as well, right now looks to me like it'll pass 15N probably around 48W which would pretty much put it about where Bill passed 15N as well if my memory is correct.

[Cookie]

A very interesting discussion make no mistake.

I remember someone else mention that the SHIPS maybe overdoing the shear levels due to the set-up, interesting to see the NHC make the same point!

Shear forecasts and intensity forecasts are just about as mysterious as woman. We have seen shear and intensity forecasts bust many times so beware.

Thanks 4 the great updates and information guys keep up the hard work

[KWT]

A very interesting discussion make no mistake.

I remember someone else mention that the SHIPS maybe overdoing the shear levels due to the set-up, interesting to see the NHC make the same point!

Shear forecasts and intensity forecasts are just about as mysterious as woman. We have seen shear and intensity forecasts bust many times so beware.

Gosh yeah the upper level features are horrible to forecast, the models quite often don't handle ULL features at all well, so it may well have an effect.

Convection looking much stronger again, interesting to see its west of where the circulation was before, wonder if we will see a relocation?

[vbhoutex]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

I may be totally wrong but I don't see this gaining a lot of latitude anytime soon. It is approaching both dry air and shear and it is not a well developed system yet. I will not be at all surprised if it ends up becoming an open wave again for a while. I am certainly no pro at this, but unless TD4 gets quite a bit stronger quickly I don't see it doing much anytime soon intensity wise. That would then lead to a probable more Southerly track than currently progged and a track in the the NE Carib would not be a surprise to me. JMHO

[ROCK]

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm1.html

[KWT]

What seems to be happening is the system is sort of stair stepping, the LLC is running near due west but the new convection blows up further WNW and the LLC sorta get tugged towards the convection which is the process which is allowing the system to gain some latitude.

[MGC]

TD#4 looks to be moving almost due west to me, not the WNW the NHC is saying. The depression looks to be slowly becoming better organized and might become a tropical storm later tonight. I expect gradual intensification in the short term. Future track past 5 days is the big question. Would not be surprised to see a east coast threat.....MGC

[Gustywind]

[KWT]

Models really do seem quite suggestive of this system recurving and we are starting to get to the time where recurving becomes increasingly likely.

The system is looking pretty good now though, the NHC may well be tempted to upgrade this one, but doesn't look like its going to have a long shelf-life!

[Gladstone]

What is a "5-WAVE PROGRESSIVE PATTERN"?

I believe the 5-Wave Pattern being referenced is the Polar Vortex. This vortex can take only one of two forms, either a 3-Wave or a 5-Wave pattern. Each 'wave' is a lobe on the vortex.

The best way to view this is from the North Pole:

http://raleighwx.easternuswx.com/models ... TNH120.gif

(Hello everyone!)

[OURAGAN]

It's racing to 275° West for the moment,you can't control mother nature as you think

[tolakram]

What is a "5-WAVE PROGRESSIVE PATTERN"?

I believe the 5-Wave Pattern being referenced is the Polar Vortex. This vortex can take only one of two forms, either a 3-Wave or a 5-Wave pattern. Each 'wave' is a lobe on the vortex.

The best way to view this is from the North Pole:

http://raleighwx.easternuswx.com/models ... TNH120.gif

(Hello everyone!)

Thanks for the info gladstone, and welcome!

[KWT]

It's racing to 275° West for the moment,you can't control mother nature as you think

Yeah that looks about right to me right now, though it does seem to be stair-stepping to a degree. Looks like 35kts to me at the moment.