Tuesday, September 29, 2015

Tuesday Morning Tropical Update: Starting to Hone in on Solutions

Good morning once again. Now that the stage has been set for at the very least a very wet week ahead lets start to iron out some finer details. I am going tofocus on Tonight into tomorrows rain event then give you updates on Tropical Storm Joaquin. I do not have the time this morning to go into great detail and will save that for tonight.

Here are updated model projections for cold front passing though tonight into tomorrow..

You can see the low pressure center developing on the front and just to the west. This is a little more west than yesterday so the heaviest rains might be more west as well. Here is rainfall through tomorrow..

Now lets focus back on the tropics. Here is the latest projection from the National Hurricane Center..

You can see the cone of possibilities and also the uncertainty with this system.  Right now it appears two potential outcomes are evolving.

Outcome 1: The tropical storm get more absorbed in the frontal boundary and it "sheers off" its major development. This would mean heavy rainfall but no destructive winds.

The GFS operational model is showing this..

The European is also trying to do this as well.

However, many of there ensemble members do in fact show a stronger storm due to..

Outcome 2: The tropical storm does not get sheered off by the frontal boundary and strengthens more. This would then the chance for a very powerful storm to turn into the coast.

The hurricane models (not always reliable) have been consistently hinting at this..

Don't get too worked up yet, I do not this think is a likely outcome. 

We need to now turn to the ensemble guidance which takes the main models and adjusts them for potential error. You can see the GFS ensemble has a big spread still..

Looking closely you can see all the different low pressure centers from the ensemble. This represents where this storm can go based on GFS model.  This shows you how there is high degree of uncertainty of how strong this storm really gets.

To sum it all up, here are the updated tracks from most major models..

You can see the spread but notice many members continue to show the storm effecting somewhere between NYC and the Carolina's. I will note these are not all strong storms for all of those lines but some are quite impressive.

Yes the worst case scenario is on the table but it is not likely at this time. Right now expect heavy rain this weekend and keep checking in for updates. 

I am going to try to nail this thing down sometime tomorrow night or Thursday morning. Right now there is so much going on that its almost impossible for models to nail this down.

Update at 730 tonight after todays model runs. 


  1. Yes, it is kind of creepy how a lot of those model runs converge on a shore strike in south Jersey, pretty close to where Sandy hit. Would be late Sunday or early Monday I gather, whereas Sandy was late Monday / early Tuesday. Luckily, we're still 5 days out, and the model lines will be wiggling all over the place. But then again, the Euro pinned Sandy down pretty early. So keep us posted on that as you have time. Thanks Willy. Jim G

  2. Jim If the 0z gfs agrees w the 18z that just came out along w it's ensembles, the heat is really gunna get turned up on this big time!