Friday, September 2, 2011

Early analyses of Katia, Lee, other things of interest.

The Atlantic basin (The Atlantic and Caribbean) took its time to produce a hurricane this year. However, as we're all unfortunately aware, that all came to an end last week.  Now One week after Irene, we have Katia starting to flex her muscles , newly named Lee in the GOM (Gulf Of Mexico), a low pressure system south of Halifax Nova Scotia that is being monitored.  What I'm going to try to do is sort it out a bit....and give a little insight into how things look at this early stage.  Mind you things can and most likely will change next week....this analyses will be a good overview of how it looks at this time; it will set the stage for  more later... when more detailed information and better model data become available.

First, how is a forecast made? I can't speak for anyone but myself. However, this is how I do it.  I was taught that when making a forecast;  the first thing I had  to do was get a feel of what's going on. Then apply  my insight and knowledge on how I thought things would unfold weather-wise (I guess sort of hearing what the storm is thinking). Then and only then, should I look at the weather models. After looking at the models I would apply what I knew about their strengths and weaknesses, then based on that  throw out model runs that didn't look right.  Then watch the existing  models a bit and see if they trend toward my original thinking...If they do I'm on the right track. IMO this makes how the storm unfolds easier to understand and makes the forecast much more accurate.  Also, you don't want to spend all your time watching the models. I feel it's better to see how the atmosphere is responding to what's going on. If you know what you're doing you should pick things up faster than the models will. Remember models are only a tool....a  forecast is based on many things not the least of which is a feeling.

Katia was downgraded to a tropical storm during the overnight , However, She  regained her status as a hurricane this morning,  The downgrade happened because of the dry to her north. This dry air as been effecting Katia for a few days. it's been what's been keeping her growth in check. However, she is now over waters that are more inductive of intensification. The National Weather Service was her moving in a west-northwesterly direction. We will see strengthening over the next few days. Katia is  expected reach major hurricane status by early next week. The models continue to shift farther west, as does the forecast track. At this time Katia looks to track west enough to give us a scare at least. As of right now, there were no coastal warnings or watches in effect for the east coast.


As of this morning Tropical Depression 13 now has the name Lee. An upper low over southwest Louisiana to the northwest of the storm is still imparting some shear  , but not as much as yesterday. Also, there is dry air that is affecting the storm . All of this is responsible for Lee's lopsided look . Lee's outflow is very limited on the western side; with most of the convection off to the eastern side, it should  keep the storm from intensifying  too quickly.   The storm looks to dump between 10 to 15 inches of rain on much of the Louisiana, Mississippi and Alabama coastlines.This is because Lee is moving extremely slow ( at this time 2 mph). So what does this have to do with  Upstate NY and New England? Right now, it looks like next week  moisture from TS Lee in Louisiana  might move up a front that should stall. Some of the models are showing  1-4" totals from the Mid Atlantic up into New England.

                                             QPF forecast for the next 5 days

First off we're going to have rain / t-storms this weekend. Some of the thunderstorms could drop locally heavy rain fall.  If we tap into any moisture from Lee/Katia it would make things that much worse.  

As for Katia and Lee, This is in no-way a forecast, this is where my thinking is right now. We are way to far out for track forcast. However, here is a general overview of what could happen

1) If the trough takes too long  to establish itself in the east. Katia come far enough west to brush the Outer Banks of NC.....this would be similar to Irene.  However, she most likely would move out to sea before a landfall and go out to sea. That said she would still bring heavy rainfall to the Mid Atlantic states.  In this scenario Lee would most likely dissipate in the SEUS.  

2)  If the trough reaches the east in time Katia would be turned  out to sea. However,  Lee  could sneak behind the trough and move NE. Most likely staying just west of the Appalachians. which would bring heavy rain into both western PA and NYS

3) WE also could end up with both systems effecting us. If Lee tracks over or just east of the Appalachians and Katia comes fairly close to the east coast  we would have rain from both systems.

At this time I see no way the tropical systems would give us the kind of rain we saw with Irene. However, do to the historic flooding we've already seen....rainfall of 3-5 inches would have a huge impact.

Other things of interest:

Invest 94L  Is a low pressure system located about 460 miles south-southeast of Halifax Nova Scotia . upper level winds are becoming unfavorable , however it still has a medium chance (40%) of becoming a tropical system. I think this system will fall apart over the next few days....but their is a chance I could be wrong........regardless of what it would have no impact on us.

Like I said,  Katia is too far out to forecast a track along or near the east coast. However, I think she will come close enough to scare us.  but not make a US landfall.  Right now, I'm more worried about possible rain from Lee than anything from Katia. Things will most likely change in the next few days.......I will keep you up to date as I get a better feel for what's going to happen.


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