'Katia' could bring East Coast a 919 mb hurricane as per ECMWF

The ECMWF model is projecting a 919 millibar hurricane to aim for the East Coast. In case you don't know how ridiculously strong that is, it is an EXTREMELY big deal. However, remember that ECMWF did not do too well with Irene, so this should not be taken too seriously at this stage.

ECMWF goes west with Invest 92L; East Coast At Risk

Pre-reading notes: ECMWF did well with track of Hurricane Irene but did not do too well with strength in forecasts. We are using ECMWF only because we believe this is the more important model of the GFS/ECMWF comparison. This bulletin is for August 29.

The 12z ECMWF run has fled west with Invest 92L, posing a potentially serious threat to the East Coast yet again. While Hurricane Irene was a minor hurricane (below category 3) at landfall, this system, which would be called Katia, could pose a significant risk to the East Coast (EC) if this verifies.
The time period we are looking at today is the September 6-8 area, when 'Katia' could begin to approach the Florida region. Each image is 24 hours from the previous image.

September 6

So here is 'Katia' on September 6. She is storming NW towards the Florida area. If this were to verify, Katia would likely scrape up the Florida coast and probably come dangerously close to the OBX region again, possibly hitting New England by the time it all ends. However, there remains the potential of Katia going out to sea after the OBX hit instead of New England.

September 7

September 7 features Katia growing massively in size and strengthening as a result. The big question going around is how storms like this manage to sometimes go out to sea. Here's the thing. Another ridge (high pressure) is forecast to develop in the CONUS (continental US) and move eastward. There appears to be a trough of low pressure moving eastward. Depending on how strong or weak it is will determine the ultimate track. If the trough is stronger, the storm will go out to sea (OTS). If it is weaker, as the ECMWF has picked up on here, the storm will have a shot at an East Coast landfall. If you don't understand all of that, focus in on the italicized part.

September 8

At this point, Katia is a monster. She has grown exponentially and strengthened a deal more in a one day period. The ECMWF continues bringing up the storm NW towards the East Coast.

You might be asking 'Okay, so when does the decision making come on whether this trough will make the storm go out to sea or towards the US?' That is an excellent question. Comparing other models against the ECMWF, it looks like we cannot answer that right now, but it would come beyond 5 days from now, so a lot of model watching is to be done.

ECMWF considerably north with Invest 92L

This is a special update for Invest 92L.
The ECMWF, proven to be more accurate than the GFS, has taken a dramatic turn north with Invest 92L, sending it out to sea instead of potentially impacting the East Coast. But first, let's take a look at the invest itself.

Invest 92 is quite a vigorous tropical wave that has barely moved offshore of Africa. Already it has a 70 percent chance of becoming a tropical system. Right now, it is moving westward. It does appear that the ECMWF may have initiated a bit north of where the system is now. While that may not seem like a huge deal, in the long run it could determine where the system goes.

Hour 168

So here is hour 168 of the ECMWF. The ECMWF itself has moved north since the 0z run early this morning. However, the model still keeps Invest 92 strong and positions itself into a hurricane Category 1 at minimum. Wind speeds are expected to top 100 knots, but this is considered long range model guidance and should not be taken too seriously at this stage.

Hour 192

At hour 192, Invest 92L has strengthened in size and wind speed, indicating the system is feeding off of what the Atlantic has to offer. Again, this is north of the 0z run.

In these last 2 frames, we see the transition of how the hurricane begins to swerve OTS (out to sea) in a NE direction.

We will monitor this through the night and brief you tomorrow morning.

August 28: Invest 92 could create more tropical worries for the East Coast in early September

Hour 192 of ECMWF

This is the ECMWF model at hour 192. Anything beyond hour 120 in any model could be inaccurate. So take this information with a fairly large grain of salt. Anyways, the ECMWF is portraying a tropical cyclone to approach the East Coast. Going WNW towards the East Coast, I would expect this system to go OTS (out to sea).

Hour 216

At Hour 216 of the Euro (ECMWF), the system continues a WNW movement. Now, the farther it goes on this WNW movement increases the chance of a landfall. That's right, a landfall on the East Coast. The reason this doesn't happen often is because of many factors that make tropical systems suddenly turn NE, then get thrown out to sea. But again, the more time this system spends going WNW decreases the chances of it going OTS.

Hour 240

This is where it gets concerning. At that point in time - Hour 240 - Invest 92 appears to be too far west to be effectively thrown out to sea. This could spell catastrophe if that doesn't happen, as the ECMWF appears to be gradually strengthening this system at this stage. We have detailed an outline of what this system would have to do to go OTS (out to sea).

Look at just how difficult it would be for this system to go out to sea without affecting land to a certain degree. This is not out of the question, but with every frame of this model run pushing this storm WNW continues to slice off a chance of an OTS ending for this storm.

(Note: It has been discovered that the ECMWF is more accurate than the GFS. Also, I had to regain my energy from the Irene frenzy yesterday, thus the low posting.)
(Note: Anything beyond 120 hours could be inaccurate, no matter what model is used.)