Tropical Storm Leslie Update #4

Once again we are going to get into the heart of the matter right away in regards to Leslie. Above is the steering currents assuming that the pressure on Leslie is less then 999 mbs. This shows a general west to northwest steering with a break or weakness in the ridge. This will allow Leslie to take a turn more towards the Northwest and then eventually to the north...
As we mentioned on our facebook page earlier in the afternoon yesterday things have not been going to plan (at least according to NHC plan) as this was suppose to be a hurricane at one point and time already but as we pointed out that the shear and the dry air and the fact that earlier in the day the decoupling had occurred between the mid level vortex and the lower level center. 

As we look at some recent images of Leslie with the visible at the top and then the wide view water vapor in the middle and then a closer look at the water vapor. Water vapor images continue to show dry air off to the west of the system and also into or just north of the system. Visible shows a blow up of some colder cloud tops but all this convection is occurring south of where they feel that the center is located. 

We are curious to see , especially when viewing the 700, 500, 200 vorticity levels if by chance because the convection is further south and the system is over all a weaker system and still disorganized if the center is not trying to relocate further to the south. At this point and time this is speculation but it is something we need to keep an eye on.

Again, you can see that Leslie is still NOT a vertically stacked system and this is just one of the reasons why leslie has not become a hurricane yet. Another reason is because of the Anti cyclone on her western side which is producing shear across the system. National Hurricane Center had placed the intensity at 55 knots but based on latest water vapor and satellite images this may actually be to generous.

As has been the case the Divergence and convergence have been decent for this system.. This is normally a positive factor for developing cyclones but there are two things that are presently working against this strengthening.
1. Its forward speed... (this should slow down once the North turn commences)
2. The Shear.. Remember shear is good for Severe thunderstorms but in Tropical cyclones it hinders and slows development..

As you can see to the north , west and east and even to the south the shear is increasing across the system. This very fact alone should keep the strength of the system in check for the immediate future. Matter of fact we would not be surprised to see it weakening more with shear expected to even increase further over the next 24 or so hours..

Lets look at tonights guidance and one common theme seems to be in place tonight with the Global Models and that is track is slightly further west and in some cases such as the ECM it takes this system very close to Nova Scotia...

This is well west and well stronger compared to its 00z run...

Here we have the GGEM which has also come west..followed by the GFS ..followed by the NOGAPS.. As you can see pretty much all the models are expecting Leslie to regain strength after the environmental conditions improve across the Atlantic. They also continue to indicate a very large system down the road by about 120-144 hrs.

One thing that we like to mention is that the guidance is starting to build back a ridge to the east of the system in the medium range..

Depending on how strong that ridge gets will determine how far west Leslie will be able to get to the USA . Right now ..It would appear that Nova Scotia may be a reasonable point for where this is heading. However we are still a good 7-10 days away before it would even be a threat towards that region and as we know these model runs can change in 6-12 hrs. 

Latest on Leslie from NHC as of 5 AM is as follows:

..LESLIE STRENGTHENS SLIGHTLY AS IT CONTINUES TO MOVE NORTHWESTWARD AWAY FROM THE LEEWARD ISLANDS...

5:00 AM AST Sun Sep 2 Location: 20.8°N 59.5°W Moving: NW at 15 mph Min pressure: 994 mb Max sustained: 70 mph

We will continue to monitor the situation thru the days ahead ..and the next update will be with in 24 hrs...

From all of us to all of you and your loved ones a very Happy Labor Day! We will be here tracking Leslie and keeping you aware of the latest current conditions..