ATL: MARIA - Post-Tropical - Discussion

[ROCK]

then it stalls and waits for a trof to give her an exit.....

[KWT]

Hmm does seem a slightly odd run in that the system manages to move NW as the upper high starts to restrengthen again.

[rainstorm]

looks better than 12z. JB hasnt given up!!

[HurricaneWarning92]

Lol suddenly the ridge is just there for decoration with the purple colors without having influnce on the track. Next please.

[ROCK]

so its not there on the 12Z to being massive on the 18Z but does nothing to the track.....GFS must have blown a vacuum tube or something...

[KWT]

I can only guess the upper levels show a different pattern, afterall you can have a feature at 500mbs but have the jet drop southwards at say 200mbs and the hurricane will lift up still...

Still does seem a little unusual...though i admit I HAVE seen it happen like the GFS shows...

[Vortex]

Maybe someone can explain how it can turn right into that ridge...I cant figure it out ...

[cycloneye]

Maybe someone can explain how it can turn right into that ridge...I cant figure it out ...

Maybe one of our resident pro mets can help us understand about this.

[longislandguy]

Is it just me or do the current analytics on TD14 seem eerily similar to that of Irene?

[SFLcane]

18z GFS has a trof which comes and weakens what ever is left of the non-existent ridge this season and recurves the cyclone.

Looks about right to me. Story of the season thus far.

[SouthDadeFish]

Maybe someone can explain how it can turn right into that ridge...I cant figure it out ...

If you look at the 500mb winds it is not moving through the ridge. The ridge extends as far west as where it shows 14L recurving. The GFS shows strong troughing over the E Coast of the United States. The 500mb winds give a better depiction of the pattern than the 500mb heights do.

Here is the 18Z GFS 500mb winds at 144 hours which clearly shows how far west the ridge extends and 14L is getting picked up by the trough over the SE US:



Look how the clockwise flow of the ridge ends far from the E Coast of the U.S.

On a side note I still think the GFS is moving this thing way too quickly.

[painkillerr]

Still due west...

http://www.ssd.noaa.gov/goes/flt/t3/loop-vis.html

[MWatkins]

I don't know how to do the right kind of linking, so here's the link out to the 18Z GFS at 138.

http://mag.ncep.noaa.gov/GemPakTier/Mag ... _rh_ht.gif

If you look at the 500 MB height lines, you can see the difference in the placement of the surface high vs. the mid layers:

The chart referenced before is showing surface pressure. However, as we talk about all the time, the mean layer (500MB) is the place to look for steering with a well-developed tropical cyclone.

Although, it is debatable how well-developed the cyclone is in the model at 138, but it is reflecting at 500MB.

Notice the trough over the US east coast, and how little ridging is left north of the system. The system is also due west of what is left of 594 height contour, so this makes total sense in terms of steering.

Whether the GFS completely handles the evolution of the trough and ridge pattern is another matter, but based on this solution, I would expect this sytem to be moving NNW in the mean layer flow.

Hope this helps.

MW

[KWT]

Will have to see how the shear ahead behaves, suspect we could have a more sheared system soon if the models are right.

[cycloneye]

Still due west...

http://www.ssd.noaa.gov/goes/flt/t3/loop-vis.html

Moved your post from the models thread to here.

[KWT]

Yeah that makes perfect sense, pretty clear there is an upper trough there, I suspect the ECM probably isn't that much different in terms of actual pattern just it keeps TD14 weaker for longer so it gets further west in the first place.

[cycloneye]

I don't know how to do the right kind of linking, so here's the link out to the 18Z GFS at 138.

http://mag.ncep.noaa.gov/GemPakTier/Mag ... _rh_ht.gif

If you look at the 500 MB height lines, you can see the difference in the placement of the surface high vs. the mid layers:

The chart referenced before is showing surface pressure. However, as we talk about all the time, the mean layer (500MB) is the place to look for steering with a well-developed tropical cyclone.

Although, it is debatable how well-developed the cyclone is in the model at 138, but it is reflecting at 500MB.

Notice the trough over the US east coast, and how little ridging is left north of the system. The system is also due west of what is left of 594 height contour, so this makes total sense in terms of steering.

Whether the GFS completely handles the evolution of the trough and ridge pattern is another matter, but based on this solution, I would expect this sytem to be moving NNW in the mean layer flow.

Hope this helps.

MW

Thank you Mike for explaining in detail all about this. So in other words,that turn will occur after the cyclone impacts the NE Caribbean islands right?

[painkillerr]

Still due west...

http://www.ssd.noaa.gov/goes/flt/t3/loop-vis.html

Moved your post from the models thread to here.

... I got lost between threads! Thanks Luis!

[Gustywind]

http://www.weather.com/weather/hurrican ... 2011-09-05


Tropical Depression Fourteen Forms

Tropical Depression Fourteen has formed about midway between Africa and the Windward Islands.

As you can see on the projected path below, Tropical Depression Fourteen is expected to gather strength over the next several days, gaining the name "Maria" once reaching tropical storm status.

It's expected to near the Lesser Antilles Friday, the Virgin Islands/Puerto Rico Saturday. Interests in those areas should pay close attention to the progress of this new system.

It is much too soon to determine if T.D. Fourteen (later, "Maria") will threaten the Bahamas or any part of the U.S. Again, interests in those locations should continue to monitor the progress of this system here at weather.com.

[KWT]

Yep not gaining much latitude now, to be honest the models keep it west and weak for a little while yet so that makes sense. I suspect like the GFS shows a threat to the NE Caribbean is possible but main strengthening to the north of the islands...maybe like some of the 95 hurricanes?