Wednesday, September 5, 2012

Leslie Still In No Hurry To move..

We are starting with a look at ADT and where the center is located for Tropical Storm Leslie. According to ADT : 25:20:04 N Lon : 62:51:28 W . It seems as if the center is trying to contract more and move under neath the heavier convection. If you look at the movement focusing on the center 
Center Movement! 

You can see that the movement has been relatively stationary.  The next thing we take notice to is the pressure is dropping and is now down to 992 mbs. However..it appears as if the winds are not yet catching up to the pressure dropping.


Next thing that one has to take notice to is the extremely large size of Tropical Storm Leslie. This is one contributing factor as to why this has not become a hurricane yet. Another contributing factor which the models I do not believe take into consideration is the fact that since this has been stationary for quite some time now it is causing cooler waters to upwell which also will slow down the intensification process.
Still yet another reason that we have not really seen Leslie become a hurricane yet is because the shear is kind of high across the system from 10-30 knots...

The good news is that the shear is starting to decrease. Once this shear decreases it should be easier for Tropical Storm Leslie to become better organized. 
Another factor is the system has still yet to become vertically stacked as the 200, 500, 700 mb levels show.


And for the first time since we been tracking this system it is no longer in the best convergence and divergence. 

Those areas are mainly to the south of the system or in the case of the bottom image over the southern part of Leslie.
Steering currents suggest very weak flow ..However a slow Northwest ward movement is occurring. But as we mentioned the system is not in a hurry ..as it has only been moving or jogging about .2 N and .2 W so about 2 MPH..

Guidance is starting to come into better agreement ..However we still have some timing issues and in addition to timing issues ..it would appear that the GFS is the right side outlier. Majority of your guidance is pointing towards a Nova Scotia landfall..



This is the GGEM which gets the system down to about 956 mbs and makes landfall in Nova Scotia. 


As you can see this is the 00z NOGAPS and it is slightly west of the GGEM but it still has the general theme with landfall in Nova Scotia..

This is the 00z ECM and it appears somewhat west again of the 12 Z ECM and is really more consistent with its prior two runs before the 12 Z run yesterday and this would appear to take Leslie into Nova Scotia as well..

Then we have the GFS which comes close to Nova Scotia but never makes any actual landfall..
We sincerely feel that the GFS would be an outlier to the east ..and is to far to the east. Just in is some better pictures of the ECM..

As we stated earlier yesterday when we received a comment about it should be now safe to say that SNE is out of the game for Leslie that with guidance still showing as close as what it is showing and still being 5-6 days away it is never safe to "assume" anything.
The ultimate track is all going to depend on how strong the ridge is able to build to the north and east of Leslie. If the ridge ends up being stronger then expected then a more western track can be anticipated. 
We have no change in our thinking with the track from over night last night with the landfall being in Nova Scotia..However..since the guidance does get kind of close to southern New England and the fact that Leslie will only grow in size this means that the wind shield will also grow in size.
Also earlier in the evening NHC mentioned a jog to the west..If this occurs more frequently this would also help with bringing this system closer to the east coast. So things still need to be monitored and we will update this in another 24 hrs...

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